Hydrocracking catalysts and processes employing non-zeolitic molecular sieves

FIELD OF THE INVENTION
The present invention relates to hydrocracking catalysts comprising non-zeolitic molecular sieves and to processes employing such hydrocracking catalysts.
BACKGROUND OF THE INVENTION
The literature on such catalysts and processes is quite extensive. Certain technical areas have been addressed as of particular interest as is readily apparent based on the large numbers of patents on certain technical topics, e.g., the use of certain zeolites in hydrocracking catalysts. Representative of the patents in this area are those relating to the use of ZSM-type zeolites in hydrocracking and include: U.S. Pat. No. 3,894,934 (ZSM-5); U.S. Pat. No. 3,871,993 (ZSM-5, ZSM-11, ZSM-12 and ZSM-21); U.S. Pat. No. 3,702,886 (ZSM-5); and U.S. Pat. No. 3,758,403 (ZSM-5 in combination with zeolite Y) of and U.S. Pat. No. 3,972,983 (ZSM-20).
Although the aforementioned patents on the use of ZSM-type zeolites in hydrocracking catalysts are of interest, the use of these zeolites has not been of significant commercial interest to date. The commercially significant activity in the hydrocracking area has been for the most part directed to further elaboration on the basic hydrocracking technology which has arisen in relation to zeolite Y, as disclosed in U.S. Pat. No. 3,130,007.
The development of hydrocracking catalysts based on a Y-type zeolite has taken many directions. Illustrative of the various processes which have arisen are those disclosed in the following patents:
U.S. Pat. No. 3,293,192 discloses a "synthetic ultra stable zeolitic aluminosilicate of the Y-type (see: U.S. Pat. No. 3,594,331 which discloses that Z-14HS is zeolite Y) which has been prepared by calcining a low alkali metal Y zeolite and successively base exchanging the calcined product with a base solution containing ammonium or complex amino salts until the alkali content is less than 1 weight percent and the calcining this product.
Although there has been extensive development of Y-type hydrocracking catalysts there has been little development of truly new hydrocracking catalysts based on the development of new molecular sieve components. This paradox, the lack of new catalytic materials despite the sizable economic interest, is readily understood by an appreciation of the fact that the work horse of the commercial hydrocracking business is zeolite Y. As a result, the patent literature discloses the clear preference towards improving zeolite Y.
The existence of zeolite Y and its use as a catalyst for hydrocracking processes is now well accepted if not, in fact, legendary. Still, the state of the art relating to zeolite Y and its use in hydrocracking catalysts has been generally limited to ion-exchange techniques, aluminum extraction techniques, catalyst formulation techniques and to secondary treatment processes which tend to remove aluminum from zeolite Y.
The instant invention is distinguished from the hydrocracking catalysts and processes of the prior art by employing a novel family of non-zeolitic molecular sieves which may be employed alone or in conjunction with the catalysts traditionally employed in hydrocracking processes. These novel non-zeolitic molecular sieves are unique in their ability to provide products with product distributions different from those obtained by use of catalysts derived from zeolitic aluminosilicates.

BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plot of the yield of the light gasoline fraction as a function of conversion for a reference catalyst (Catalyst A) and a catalyst (Catalyst B) of this invention.
FIG. 2 is similar to FIG. 1 except Catalyst C, according to this invention, is depicted.
FIG. 3 is plot of the calculated RON (Research Octane Number) of the light gasoline fraction as a function of conversion for Catalyst A and Catalyst B.
FIG. 4 is similar to FIG. 3 except Catalyst C is depicted.
FIG. 5 is plot of the yield of the heavy gasoline fraction as a function of conversion for Catalyst A and Catalyst C.
FIG. 6 is a plot of the yield of the heavy gasoline fraction as a function of conversion for Catalyst A and Catalyst B.
FIG. 7 is a plot of the iso to normal ratio for C.sub.5 hydrocarbons as a function of conversion for Catalyst A and Catalyst C.
FIG. 8 is a plot of the iso to normal ratio for C.sub.6 hydrocarbons as a function of conversion for Catalyst A and Catalyst C.
FIG. 9 is a plot of the iso to normal ratio for C.sub.5 hydrocarbons as a function of conversion for Catalyst A and Catalyst B.
FIG. 10 is a plot of the iso to normal ratio for C.sub.6 hydrocarbons as a function of conversion for Catalyst A and Catalyst B.
FIG. 11 is a plot of the iso to normal ratio as a function of carbon number for Catalyst A and B.
FIG. 12 is a plot of the C.sub.3 yield as a function of conversion for Catalyst A and Catalyst C.
FIG. 13 is a plot of the C.sub.3 yield as a function of conversion for Catalyst A and Catalyst B.

SUMMARY OF THE INVENTION
The present invention relates to hydrocracking catalysts and to hydrocracking employing such catalysts. The catalysts comprise at least one non-zeolite molecular sieve, as hereinafter described, at least one hydrogenation catalyst (noble or base metal) component and, optionally, particles of a traditional hydrocracking catalyst as heretofore employed and having catalytic activity for hydrocracking hydrocarbon feedstocks at effective hydrocracking conditions, e.g., particles of a traditional hydrocracking catalyst containing a zeolitic aluminosilicate(s) of the type generally employed in such hydrocracking catalysts. The non-zeolitic molecular sieves employed in the instant invention are characterized in their calcined form by an adsorption of oxygen of at least 4 percent by weight at a partial pressure of 100 torr and a temperature of -186.degree. C. The traditional catalyst component, e.g., a zeolitic aluminosilicate, if any, is characterized as being a hydrocracking catalyst component, such as heretofore traditionally employed in hydrocracking processes, e.g., the various forms of zeolite Y, silica-alumina, and hydrogenation components. The non-zeolitic molecular sieves employed in this invention are unique in that such are not zeolitic aluminosilicates (See: Zeolite Molecular Sieves, by D. W. Breck (1973)), as heretofore employed in the prior art, but are novel non-zeolitic molecular sieves, as hereinafter described.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to hydrocracking wherein high boiling hydrocarbon feedstocks are converted to lower boiling products by cracking the high boiling hydrocarbon feedstock components and hydrogenating unsaturates in the present product.
Hydrocracking processes and the effective conditions for carrying them out are well known in the art (see: Zeolite Chemistry and Catalysis, by Jule A. Rabo, ACS Monograph 171, Chapter 13 (1976)). Hydrocracking is known to be of several general types. Two well known types of hydrocracking include the single-stage type and the two-stage type. In the single-stage type (Unicracking-J.H.C. or Jersey Hydrocracking) process the feedstocks are pretreated to remove essentially all sulfur and nitrogen, e.g., by a hydrotreater, wherein desulfurization and denitrification are effected. The hydrocarbon stream is then hydrocracked in a reactor in the presence of a catalyst at a single pass conversion of between 40 and 70 percent. Any unconverted hydrocarbon may be recycled to extinction following scrubbing for ammonia removal and fractionation for separation of converted products. The two-stage process (Unicracking-JHC) has been developed which provides a second stage that employs the effluent from the single-stage type hydrocracking process (after passage through an ammonia scrubber) and from a second hydrocracking reactor as the input feed for a fractionation unit. The unconverted feedstock is then recycled to extinction in the second hydrocracking reactor. Because the catalyst in the second hydrocracking reactor operates in an essentially ammonia-free environment the rate of conversion in this reactor can be maintained at a higher level, e.g, 60 to 80 percent and typically is carried out at a lower temperature than the first-stage reactor.
It has been found that the use of specific non-zeolitic molecular sieves provide different product distributions when such non-zeolitic molecular sieves (associated with a hydrogenation component) are employed and, optionally, when employed in conjunction with conventional hydrocracking catalysts having activity at effective hydrocracking conditions. Heretofore, the zeolite-containing hydrocracking catalysts of the prior art have required that certain penalties be endured for the optimization of particular process variables or product characteristics, e.g., octane. For example, an improvement in gasoline octane of the products, as indicated by an increased ratio of isoparaffins to normal paraffins, has been observed to occur with a concurrent decrease in gasoline yield and in feed conversion when zeolitic aluminosilicate-based catalysts are employed. The isoparaffin to normal paraffin ratio in the gasoline product has long been employed as an indication of higher octane products and its increase or decrease used as an indication of the octane of the gasoline product. The increase in the isoparaffin in the light gasoline product (boiling below 185.degree. F.) relative to the normal paraffins occurs without increasing or significantly increasing the loss in gasoline yield and feed stock conversion and is of significant commercial importance. This increase in the isoparaffin to normal paraffin ratio in the light gasoline fraction is particularly significant, since this fraction is not generally subjected to further processing to improve its octane number.
The non-zeolitic molecular sieves employed in the instant invention are selected from the hereinafter described group of non-zeolitic molecular sieves as being characterized in their calcined form by an adsorption of oxygen of at least 4 percent by weight at a partial pressure of 100 torr and a temperature of -186.degree. C. The non-zeolitic molecular sieves are preferably characterized in their calcined form by an adsorption of isobutane of at least 2 percent by weight at a partial pressure of 500 torr and a temperature of 20.degree. C. The non-zeolitic molecular sieves employed in the instant invention are most preferably characterized by one of the aforementioned adsorption criteria and also characterized by an adsorption of triethylamine from zero to less than 5 percent by weight, preferably less than 3 percent by weight, at a partial pressure of 2.6 torr and a temperature of 22.degree. C.
NON-ZEOLITIC MOLECULAR SIEVES ("NZ-MS")
The term "non-zeolitic molecular sieves" or "NZ-MS" is defined in the instant invention to include the "SAPO" molecular sieves of U.S. Pat. No. 4,440,871, "ELAPSO" molecular sieves as disclosed in U.S. Ser. No. 600,312, filed Apr. 13, 1984 and certain "MeAPO", "FeAPO", "TiAPO" and "FCAPO" molecular sieves, as hereinafter described. Crystalline metal aluminophosphates (MeAPOs where "Me" is at least one of Mg, Mn, Co and Zn) are disclosed in U.S. Ser. No. 514,334, filed July 15, 1983; crystalline ferroaluminophosphates (FeAPOs) are disclosed in U.S. Ser. No. 514,335, filed July 15, 1983; titanium aluminophosphates (TAPOs) are disclosed in U.S. Ser. No. 480,738; and non-zeolitic molecular sieves ("ELAPO") are disclosed U.S. Ser. No. 599,978, filed Apr. 13 1984. The aforementioned copending applications are incorporated herein by reference thereto. The nomenclature employed herein to refer to the members of the aforementioned NZ-MSs is consistent with that employed in the aforementioned copending applications. A particular member of a class is generally referred to as a "-n" species wherein "n" is an integer, e.g., SAPO-11, MeAPO-34 and ELAPSO-31.
"ELAPSO" molecular sieves are described in copending U.S. Ser. No. 600,312, filed Apr. 13, 1984, as crystalline molecular sieves having three-dimensional microporous framework structures of ELO.sub.2, AlO.sub.2, PO.sub.2, SiO.sub.2 oxide units and having an empirical chemical composition on an anhydrous basis expressed by the formula:
mR: (EL.sub.w Al.sub.x P.sub.y Si.sub.z)O.sub.2
wherein "R" represents at least one organic templating agent present in the intracrystalline pore system; "m" represents the molar amount of "R" present per mole of (EL.sub.w Al.sub.x P.sub.y Si.sub.z)O.sub.2 and has a value of from zero to about 0.3; "EL" represents at least one element capable of forming a three dimensional oxide framework, "EL" is characterized as an element having a mean "T-O" distance in tetrahedral oxide structures between about 1.51 Angstroms and about 2.06 Angstroms, "EL" has a cation electronegativity between about 125 kcal/g-atom to about 310 kcal/gm-atom and "EL" is capable of foming stable M-O-P, M-O-Al or M-O-M bonds in crystalline three dimensional oxide structures having a "M-O" bond dissociation energy greater than about 59 kcal/g-atom at 298.degree. K.; and "w", "x", "y" and "z" represent the mole fractions of "EL", aluminum, phosphorus and silicon, respectively, present as framework oxides said mole fractions being within the limiting compositional values or points as follows:
______________________________________Mole FractionPoint x y (z + w)______________________________________A 0.60 0.39-(0.01)p 0.01(p + 1)B 0.39-(0.0l p) 0.60 0.01(p + 1)C 0.01 0.60 0.39D 0.01 0.01 0.98E 0.60 0.01 0.39______________________________________
where "p" is an integer corresponding to the number of elements "El" in the (El.sub.w Al.sub.x P.sub.y Si.sub.z)O.sub.2 constituent.
The "ELAPSO" molecular sieves are also described as crystalline molecular sieves having three-dimensional microporous framework structures of ELO.sub.2, AlO.sub.2, SiO.sub.2 and PO.sub.2 tetrahedral oxide units and having an empirical chemical composition on an anhydrous basis expressed by the formula:
mR: (EL.sub.w Al.sub.x P.sub.y Si.sub.z)O.sub.2
wherein "R" represents at least one organic templating agent present in the intracrystalline pore system; "m" represents the molar amount of "R" present per mole of (EL.sub.w Al.sub.x P.sub.y Si.sub.z)O.sub.2 and has a value of from zero to about 0.3; "EL" represents at least one element capable of forming a framework tetrahedral oxide and is selected from the group consisting of arsenic, beryllium, boron, chromium, cobalt, gallium, germanium, iron, lithium, magnesium, manganese, titanium, vanadium and zinc; and "w", "x", "y" and "z" represent the mole fractions of "EL", aluminum, phosphorus and silicon, respectively, present as tetrahedral oxides said mole fractions being within the limiting compositional values or points as follows:
______________________________________Mole FractionPoint x y (z + w)______________________________________a 0.60 0.39-(0.01)p 0.01(p + 1)b 0.39-(0.01 p) 0.60 0.01(p + 1)c 0.10 0.55 0.35d 0.55 0.10 0.35______________________________________ where "p" is as above defined.
The "ELAPSO" molecular sieves include numerous species which are intended herein to be within the scope of the term "non-zeolitic molecular sieves" such being disclosed in the following copending and commonly assigned applications, incorporated herein by reference thereto:
______________________________________U.S. Ser. No. Filed NZ-MS______________________________________600,174 April 13, 1984 CoAPSO600,173 April 13, 1984 FeAPSO600,180 April 13, 1984 MgAPSO600,175 April 13, 1984 MnAPSO600,179 April 13, 1984 TiAPSO600,170 April 13, 1984 ZnAPSO600,168 April 13, 1984 CoMgAPSO600,182 April 13, 1984 CoMnMgAPSO______________________________________
TiAPSO Molecular Sieves
The TiAPSO molecular sieves of U.S. Ser. No. 600,179, filed Apr. 13, 1984 have three-dimensional microporous framework structures of TiO.sub.2, AlO.sub.2, PO.sub.2 and SiO.sub.2 tetrahedral oxide units having an empirical chemical composition on an anhydrous basis expressed by the formula:
mR: (Ti.sub.2 Al.sub.x P.sub.y Si.sub.z)O.sub.2
wherein "R" represents at least one organic templating agent present in the intracrystalline pore system; "m" represents the molar amount of "R" present per mole of (Ti.sub.w Al.sub.x P.sub.y Si.sub.z)O.sub.2 and has a value of from zero to about 0.3; and "w", "x", "y" and "z" represent the mole fractions of titanium, aluminum, phosphorus and silicon, respectively, present as tetrahedral oxides and each has a value of at least 0.01. The mole fractions "w", "x", "y" and "z" are generally defined being within the limiting compositional values or points as follows:
______________________________________Mole FractionPoint x y (z + w)______________________________________A 0.60 0.38 0.02B 0.38 0.60 0.02C 0.01 0.60 0.39D 0.01 0.01 0.98E 0.60 0.01 0.39______________________________________
In a preferred subclass of TiAPSO molecular sieves the values "w", "x", "y" and "z" in the above formula are within the tetragonal compositional area defined by points a, b, c and d of the ternary diagram which is FIG. 2 of the drawings, said points a, b, c and d representing the following values for "w", "x", "y" and "z".
______________________________________ Mole FractionPoint x y (z + w)______________________________________a 0.55 0.43 0.02b 0.43 0.55 0.02c 0.10 0.55 0.35d 0.55 0.10 0.35______________________________________
TiAPSO compositions are generally synthesized by hydrothermal crystallization from a reaction mixture containing active resources of titanium, silicon, aluminum and phosphorus, and preferably an organic templating, i.e., structure-directing, agent, preferably a compound of an element or Group VA of the Periodic Table, and/or optionally an alkali or other metal. The reaction mixture is generally placed in a sealed pressure vessel, preferably lined with an inert plastic material such as polytetrafluoroethylene and heated, preferably under autogeneous pressure at a temperature between 50.degree. C. and 250.degree. C. and preferably between 100.degree. C. and 200.degree. C. until crystals of the TiAPSO product are obtained, usually a period of from hours to several weeks. Generally, the crystallization time is from about 2 hours to about 30 days and typically from about 4 hours to about 20 days. The product is recovered by any convenient method such as centrifugation or filtration.
In synthesizing the TiAPSO, it is preferred to employ a reaction mixture composition expressed in terms of the molar ratios as follows:
aR: (Ti.sub.w Al.sub.x P.sub.y Si.sub.z)O.sub.2 :bH.sub.2 O
wherein "R" is an organic templating agent; "a" is the amount of organic templating agent "R" and has a value of from zero to about 6 and is preferably an effective amount within the range of greater than zero (0) to about 6; "b" has a value of from zero (0) to about 500, preferably between about 2 and about 300; and "w", "x", "y" and "z" represent the mole fractions of titanium, aluminum, phosphorus and silicon, respectively, and each has a value of at least 0.01.
In a preferred embodiment the reaction mixture is selected such that the mole fractions "w", "x", "y" and "z" are generally defined as being within the limiting compositonal values or points as follows:
______________________________________Mole FractionPoint x y (z + w)______________________________________F 0.60 0.38 0.02G 0.38 0.60 0.02H 0.01 0.60 0.39I 0.01 0.01 0.98J 0.60 0.01 0.39______________________________________
In the foregoing expression of the reaction composition, the reactants are normalized with respect to the total of "w", "x", "y" and "z" such that (w+x+y+z)=1.00 mole. Molecular sieves containing titanium, aluminum, phosphorus and silicon as framework tetrahedral oxides are prepared as follows:
Preparative Reagents
TiAPSO compositions were prepared using numerous regents. The reagents employed and abbreviations employed herein, if any, for such reagents are as follows:
(a) Alipro: aluminum isopropoxide;
(b) LUDOX-LS: LUDOX-LS is the tradename of DuPont for an aqueous solution of 30 weight percent SiO.sub.2 and 0.1 weight percent Na.sub.2 O;
(c) H.sub.3 PO.sub.4 : 85 weight percent aqueous phosphoric acid;
(d) Tiipro: titanium isopropoxide;
(e) TEAOH: 40 weight percent aqueous solution of tetraethylammonium hydroxide;
(f) Pr.sub.2 NH: di-n-propylamine, (C.sub.3 H.sub.7).sub.2 NH.
(g) Pr.sub.3 NH: tri-n-propylamine, (C.sub.3 H.sub.7).sub.3 N;
(h) Quin: Quinuclidine, (C.sub.7 H.sub.13 N);
(i) MQuin: Methyl Quinuclidine hydroxide, (C.sub.7 H.sub.13 NCH.sub.3 OH); and
(j) C-hex: cyclohexylamine.
Preparative Procedures
Preparative examples were carried out by forming a starting reaction mixture by adding the H.sub.3 PO.sub.4 and the water. This mixture was mixed and to this mixture the aluminum isopropoxide was added. This mixture was then blended until a homogeneous mixture was observed. To this mixture the LUDOX-LS was added and the resulting mixture blended (about 2 minutes) until a homogeneous mixture was observed.
The titanium isopropoxide was added to the above mixture and the resulting mixture blended until a homogeneous mixture was observed. The organic templating agent was then added to the resulting mixture and the resulting mixture blended until a homogeneous mixture was observed, i.e., about 2 to 4 minutes. When the organic templating agent was quinuclidine the procedure was modified such that the quinuclidine was dissolved in about one half the water and accordingly the H.sub.3 PO.sub.4 was mixed with about one half the water. (The pH of the mixture was measured and adjusted for temperature). The mixture was than placed in a lined (polytetrafluoroethylene) stainless steel pressure vessel and digested at a temperature (150.degree. C. or 200.degree. C.) for a time or placed in lined screw top bottles for digestion at 100.degree. C. All digestions were carried out at the autogenous pressure.
All digestions were carried out at the autogenous pressure. The products were removed from the reaction vessel cooled and evaluated as set forth hereinafter.
MgAPSO Molecular Sieves
The MgAPSO molecular sieves of U.S. Ser. No. 600,180, filed Apr. 13, 1984 have three-dimensional microporous framework structures of MgO.sub.2.sup.-2, AlO.sub.2.sup.-, PO.sub.2.sup.+ and SiO.sub.2 tetrahedral oxide units and have an empirical chemical composition on an anhydrous basis expressed by the formula:
mR:(Mg.sub.w Al.sub.x P.sub.y Si.sub.z)O.sub.2
wherein "R" represents at least one organic templating agent present in the intracrystalline pore system; "m" represents the molar amount of "R" present per mole of (Mg.sub.w Al.sub.x P.sub.y Si.sub.z)O.sub.2 and has a value from zero (0) to about 0.3; and "w", "x", "y" and "z" represent the mole fractions of magnesium, aluminum, phosphorus and silicon, respectively, present as tetrahedral oxides and each preferably has a value of at least 0.01. The mole fractions "w", "x", "y" and "z" are generally defined as being within the limiting compostional values or points as follows:
______________________________________Mole FractionPoint x y (z + w)______________________________________A 0.60 0.38 0.02B 0.39 0.59 0.02C 0.01 0.60 0.39D 0.01 0.01 0.98E 0.60 0.01 0.39______________________________________
In a preferred subclass of the MgAPSO molecular sieves the values "w", "x", "y" and "z" in the above formula are within the limiting compositional values or points as follows:
______________________________________Mole FractionPoint x y (z + w)______________________________________a 0.55 0.43 0.02b 0.43 0.55 0.02c 0.10 0.55 0.35d 0.55 0.10 0.35______________________________________
MgAPSO compositions are generally synthesized by hydrothermal crystallization for an effective time at effective pressures and temperatures from a reaction mixture containing reactive sources of magnesium, silicon, aluminum and phosphorus, an organic templating, i.e., structure-directing, agent, preferably a compound of an element of Group VA of the Periodic Table, and may be an alkali or other metal. The reaction mixture is generally placed in a sealed pressure vessel, preferably lined with an inert plastic material such as polytetrafluoroethylene and heated, preferably under autogeneous pressure at a temperature between 50.degree. C. and 250.degree. C., and preferably between 100.degree. C. and 200.degree. C. until crystals of the MgAPSO product are obtained, usually a period of from several hours to several weeks. Generally, the crystallization period will be from about 2 hours to about 30 days with it typically being from about 4 hours to about 20 days for obtaining MgAPSO crystals. The product is recovered by any convenient method such as centrifugation or filtration.
In synthesizing the MgAPSO compositions, it is preferred to employ reaction mixture compositions expressed in terms of the molar ratios as follows:
aR:(Mg.sub.w Al.sub.x P.sub.y Si.sub.z)O.sub.2 :bH.sub.2 O
wherein "R" is an organic templating agent; "a" is the amount of organic templating agent "R" and can have a value within the range of from zero (0) to about 6 and is more preferably an effective amount greater than zero to about 6; "b" has a value of from zero (0) to about 500, preferably between about 2 and about 300; and "w", "x", "y" and "z" represent the mole fractions of magnesium, aluminum, phosphorus and silicon, respectively, and each has a value of at least 0.01.
In a preferred embodiment the reaction mixture is selected such that the mole fractions "w", "x", "y" and "z" are generally defined as being within the limiting compositional values or points as follows:
______________________________________Mole FractionPoint x y (z + w)______________________________________F 0.60 0.38 0.02G 0.38 0.60 0.02H 0.01 0.60 0.39I 0.01 0.01 0.98J 0.60 0.01 0.39______________________________________
In the foregoing expression of the reaction composition, the reactants are normalized with respect to the total of "w", "x", "y" and "z" such that (w+x+y+z)=1.00 mole. Molecular sieves containing magnesium, aluminum, phosphorus and silicon as framework tetrahedral oxides are prepared as follows:
Preparative Reagents
MgAPSO compositions were prepared using numerous regents. The reagents employed and abbreviations employed herein, if any, for such reagents are as follows:
(a) Alipro: aluminum isopropoxide;
(b) CATAPAL: Trademark of Condea for hydrated pseudo-boehmite;
(c) LUDOX-LS: Trademark of DuPont for an aqueous solution of 30 weight percent SiO.sub.2 and 0.1 weight percent Na.sub.2 O;
(d) Mg(Ac).sub.2 : magnesium acetate tetrahydrate, Mg(C.sub.2 H.sub.3 O.sub.2).4H.sub.2 O;
(e) H.sub.3 PO.sub.4 : 85 weight percent aqueous phosphoric acid in water;
(f) TBAOH: tetraethylammonium hydroxide (40 wt. % in water);
(g) Pr.sub.2 NH: di-n-propylamine,
(h) Pr.sub.3 NH: tri-n-propylamine;
(i) Quin: Quinuclidine;
(j) MQuin: Methyl Quinuclidine hydroxide, (17.9% in water);
(k) C-hex: cyclohexylamine.
(l) TEAOH: tetraethylammonium hydroxide (40 wt. % in water).
(m) DEEA: Diethylethanolamine;
(n) i-Pr.sub.2 NH: di-isopropylamine;
(o) TEABr: tetraethylammonium bromide; and
(p) TPAOH: tetrapropylammonium hydroxide (40 wt. % in water).
Preparative Procedures
The MgAPSO compositions were prepared by preparing reaction mixtures having a molar composition expressed as:
eR:fMgO:hAl.sub.2 O.sub.3 :iP.sub.2 O.sub.5 :gSiO.sub.2 :jH.sub.2 O
wherein e, f, g, h, i and j represent the moles of template R, magnesium (expressed as the oxide), SiO.sub.2, Al.sub.2 O.sub.3, P.sub.2 O.sub.5 (H.sub.3 PO.sub.4 expressed as P.sub.2 O.sub.5) and H.sub.2 O, respectively.
The reaction mixtures were prepared by three procedures, designated hereinafter as Methods A, B and C.
Method A
The reaction mixture was prepared by mixing the ground aluminum source (Al-ipro or CATAPAL) with the H.sub.3 PO.sub.4 and water on a gradual basis with occasional cooling with an ice bath. The resulting mixture was blended until a homogeneous mixture was observed. When the aluminum source was CATAPAL the water and H.sub.3 PO.sub.4 were first mixed with the CATAPAL added thereto. The magnesium acetate was dissolved in portion of the water and was then added followed by addition of the LUDOX-LS. The combined mixture was blended until a homogeneous mixture was observed. The organic templating agent was added to this mixture and blended until a homogeneous mixture was observed. The resulting mixture (final reaction mixture) was placed in a lined (polytetrafluoroethylene) stainless steel pressure vessel and digested at a temperature (150.degree. C. or 200.degree. C.) for an effective time. Alternatively, if the digestion temperature was 100.degree. C. the final reaction mixture was placed in a lined (polytetrafluoroethylene) screw top bottle for a time. All digestions were carried out at the autogenous pressure. The products were removed from the reaction vessel cooled and evaluated as set forth hereinafter.
Method B
When method B was employed the organic templating agent was di-n-propylamine. The aluminum source, silicon source and one-half of the water were first mixed and blended until a homogeneous mixture was observed. A second solution was prepared by mixing the remaining water, the H.sub.3 PO.sub.4 and the magnesium acetate. This solution was then added to the above mixture. The magnesium acetate and H.sub.3 PO.sub.4 solution was then added to the above mixture and blended until a homogeneous mixture was observed. The organic templating agent(s) was then added and the resulting reaction mixture digested and product recovered as was done in Method A.
Method C
Method C was carried out by mixing aluminum isopropoxide, LUDOX LS and water in a blender or by mixing water and aluminum iso-propoxide in a blender followed by addition of the LUDOX LS. H.sub.3 PO.sub.4 and magnesium acetate were then added to this mixture. The organic templating agent was then added to the resulting mixture and digested and product recovered as was done in Method A.
MnAPSO Molecular Sieves
The MnAPSO molecular sieves of U.S. Ser. No. 600,175, filed Apr. 13, 1984 have a framework structure of MnO.sub.2.sup.-2, AlO.sub.2.sup.-, PO.sub.2.sup.+, and SiO.sub.2 tetrahedral units having an empirical chemical composition on an anhydrous basis expressed by the formula:
mR:(Mn.sub.w Al.sub.x P.sub.y Si.sub.z)O.sub.2
wherein "R" represents at least one organic templating agent present in the intracrystalline pore system; "m" represents the molar amount of "R" present per mole of (Mn.sub.w Al.sub.x P.sub.y Si.sub.z)O.sub.2 and has a value of zero to about 0.3; and "w", "x", "y" and "z" represent the mole fractions of element manganese, aluminum, phosphorus and silicon, respectively, present as tetrahedral oxides. The moles fractions "w", "x", "y" and "z" are generally defined as being within the limiting compositional values or points as follows:
______________________________________Mole FractionPoint x y (w + z)______________________________________A 0.60 0.38 0.02B 0.38 0.60 0.02C 0.01 0.60 0.39D 0.01 0.01 0.98E 0.60 0.01 0.39______________________________________
The values of w, x, y and z may be as follows:
______________________________________Mole FractionPoint x y (w + z)______________________________________a 0.55 0.43 0.02b 0.43 0.55 0.02c 0.10 0.55 0.35d 0.55 0.10 0.35______________________________________
The MnAPSOs of this invention are useful as adsorbents, catalysts, ion-exchangers, and the like in much the same fashion as aluminosilicates have been employed heretofore, although their chemical and physical properties are not necessarily similar to those observed for aluminosilicates.
MnAPSO compositions are generally synthesized by hydrothermal crystallization from a reaction mixture containing reactive sources of manganese, silicon, aluminum and phosphorus, preferably an organic templating, i.e., structure-directing, agent, preferably a compound of an element of Group VA of the Periodic Table, and/or optionally an alkali or other metal. The reaction mixture is generally placed in a sealed pressure vessel, preferably lined with an inert plastic material such as polytetrafluoroethylene and heated, preferably under autogeneous pressure at a temperature between about 50.degree. C. and about 250.degree. C., and preferably between about 100.degree. C. and about 200.degree. C. until crystals of the MnAPSO product are obtained, usually a period of from several hours to several weeks. Typical effective times of from 2 hours to about 30 days with generally from about 4 hours to about 20 days have been observed. The product is recovered by any convenient method such as centrifugation or filtration.
In synthesizing the MnAPSO compositions, it is preferred to employ a reaction mixture composition expressed in terms of the molar ratios as follows:
aR:(Mn.sub.w Al.sub.x P.sub.y Si.sub.z)O.sub.2 :bH.sub.2 O
wherein "R" is an organic templating agent; "a" is the amount of organic templating agent "R" and has a value of from zero to about 6 and is preferably an effective amount within the range of greater than zero (0) to about 6; "b" has a value of from zero (0) to about 500, preferably between about 2 and about 300; and "w", "x", "y" and "z" represent the mole fractions of manganese, aluminum, phosphorus and silicon, respectively, and each has a value of at least 0.01.
In a preferred embodiment the reaction mixture is selected such that the mole fractions "w", "x", "y" and "z" are generally defined as being within the limiting compositional values or points as follows:
______________________________________Mole FractionPoint x y (w + z)______________________________________F 0.60 0.38 0.02G 0.38 0.60 0.02H 0.01 0.60 0.39I 0.01 0.01 0.98J 0.60 0.01 0.39______________________________________
In the foregoing expression of the reaction composition, the reactants are normalized with respect to the total of "w", "x", "y" and "z" such that (w+x+y+z)=1.00 mole. Molecular sieves containing manganese, aluminum, phosphorus and silicon as framework tetrahedral oxide units are prepared as follows:
Preparative Reagents
MnAPSO compositions were prepared using numerous reagents. The reagents employed and abbreviations employed herein, if any, for such reagents are as follows:
(a) Alipro: aluminum isopropoxide;
(b) CATAPAL; Trademark of Condea Corporation for hydrated pseudoboehmite;
(c) LUDOX-LS: LUDOX-LS is the tradename of DuPont for an aqueous solution of 30 weight percent of SiO.sub.2 and 0.1 weight percent Na.sub.2 O;
(d) H.sub.3 PO.sub.4 : 85 weight percent aqueous phosphoric acid;
(e) MnAc: Manganese acetate, Mn(C.sub.2 H.sub.3 O.sub.2).sub.2.4H.sub.2 O;
(f) TEAOH: 40 weight percent aqueous solution of tetraethylammonium hydroxide;
(g) TBAOH: 40 weight percent aqueous solution of tetrabutylammonium hydroxide;
(h) Pr.sub.2 NH: di-n-propylamine, (C.sub.3 H.sub.7).sub.2 NH;
(i) Pr.sub.3 N: tri-n-propylamine (C.sub.3 H.sub.7).sub.3 N;
(j) Quin: Quinuclidine, (C.sub.7 H.sub.13 N);
(k) MQuin: Methyl Quinuclidine hydroxide, (C.sub.7 H.sub.13 NCH.sub.3 OH);
(l) C-hex: cyclohexylamine;
(m) TMAOH: tetramethylammonium hydroxide;
(n) TPAOH: tetrapropylammonium hydroxide; and
(o) DEEA: 2-diethylaminoethanol.
Preparative Procedures
Preparative examples were carried out by forming a starting reaction mixture by adding the H.sub.3 PO.sub.4 to one half of the quantity of water. This mixture was mixed and to this mixture the aluminum isopropoxide or CATAPAL was added. This mixture was then blended until a homogeneous mixture was observed. To this mixture the LUDOX LS was added and the resulting mixture blended (about 2 minutes) until a homogeneous mixture was observed. A second mixture was prepared using the manganese acetate and the remainder (about 50%) of the water. The two mixtures were admixed and the resulting mixture blended until a homogeneous mixture was observed. The organic templating agent was then added to the resulting mixture and the resulting mixture blended until a homogeneous mixture was observed, i.e., about 2 to 4 minutes. (The pH of the mixture was measured and adjusted for temperature). The mixture was then placed in a lined (polytetrafluoroethylene) stainless steel pressure vessel and digested at a temperature (150.degree. C. or 200.degree. C.) for a time or placed in lined screw top bottles for digestion at 100.degree. C. All digestions were carried out at the autogenous pressure.
CoAPSO Molecular Sieves
The CoAPSO molecular sieves of U.S. Ser. No. 600,174, filed Apr. 13, 1984 have three-dimensional microporous framework structures of CoO.sub.2.sup.-2, AlO.sub.2.sup.-, PO.sub.2.sup.+ and SiO.sub.2 tetrahedral units and have an empirical chemical composition on an anhydrous basis expressed by the formula:
mR:(Co.sub.w Al.sub.x P.sub.y Si.sub.z)O.sub.2
wherein "R" represents at least one organic templating agent present in the intracrystalline pore system; "m" represents the molar amount of "R" present per mole of (Co.sub.w Al.sub.x P.sub.y Si.sub.z)O.sub.2 and has a value of from zero to about 0.3; and "w", "x", "y" and "z" represent the mole fractions of cobalt, aluminum, phosphorus and silicon, respectively, present as tetrahedral oxides, where the mole fractions "w", "x", "y" and "z" are each at least 0.01 and are generally defined, as being within the limiting compositional values or points as follows:
______________________________________ Mole FractionPoint x y (z + w)______________________________________A 0.60 0.38 0.02B 0.38 0.60 0.02C 0.01 0.60 0.39D 0.01 0.01 0.98E 0.60 0.01 0.39______________________________________
In a preferred subclass of the CoAPSO molecular sieves the values of "w", "x", "y", and "z" in the above formula are within the limiting compositional values or points as follows:
______________________________________ Mole FractionPoint x y (z + w)______________________________________a 0.55 0.43 0.02b 0.43 0.55 0.02c 0.10 0.55 0.35d 0.55 0.10 0.35______________________________________
CoAPSO compositions are generally synthesized by hydrothermal crystallization from a reaction mixture containing reactive sources of cobalt, silicon, aluminum and phosphorus, an organic templating, i.e., structure-directing, agent, preferably a compound of an element of Group VA of the Periodic Table, and optionally an alkali metal. The reaction mixture is generally placed in a sealed pressure vessel, preferably lined with an inert plastic material such a polytetrafluoroethylene and heated, preferably under autogenous pressure at an effective temperature which is generally between 50.degree. C. and 250.degree. C. and preferably between 100.degree. C. and 200.degree. C. until crystals of the CoAPSO product are obtained, usually for an effective time of from several hours to several weeks. Generally the effective crystallization time will be from about 2 hours to about 30 days and typically from about 4 hours to about 20 days. The product is recovered by any convenient method such as centrifugation or filtration.
In synthesizing the CoAPSO, it is preferred to employ a reaction mixture composition expressed in terms of the molar ratios as follows:
aR:(CO.sub.w Al.sub.x P.sub.y Si.sub.z)O.sub.2 :bH.sub.2 O
wherein "R" is an organic templating agent; "a" is the amount of organic templating agent "R" and has a value of from zero to about 6 and is preferably an effective amount within the range of greater than zero (0) to about 6; "b" has a value of from zero (0) to about 500, preferably between about 2 and 300; and "w", "x", "y" and "z" represent the mole fractions of cobalt, aluminum, phosphorus and silicon, respectively, and each has a value of at least 0.01. In a preferred embodiment the reaction mixture is selected such that the mole fractions "w", "x", "y" and "z" are generally defined as being within the limiting compositional values or points as follows:
______________________________________Mole FractionPoint x y (z + w)______________________________________F 0.60 0.38 0.02G 0.38 0.60 0.02H 0.01 0.60 0.39I 0.01 0.01 0.98J 0.60 0.01 0.39______________________________________
For reasons unknown at present, not every reaction mixture gave crystalline CoAPSO products when reaction products were examined for CoAPSO products by X-ray analysis. Those reaction mixtures from which crystalline CoAPSO products were obtained are reported in the examples hereinafter as numbered examples and those reaction mixtures from which CoAPSO products were not identified by use of X-ray analysis are reported as lettered examples.
In the foregoing expression of the reaction composition, the reactants are normalized with respect to the total of "w", "x", "y" and "z" such that (w+x+y+z)=1.00 mole. Molecular sieves containing cobalt, aluminum, phosphorus and silicon as framework tetrahedral oxide units are prepared as follows:
Preparative Reagents
CoAPSO compositions were prepared using numerous reagents. The reagents employed and abbreviations employed herein, if any, for such reagents are as follows:
(a) Alipro: aluminum isoproproxide;
(b) CATAPAL: Trademark of Condea Corporation for pseudoboehmite;
(c) LUDOX-LS: Trademark of DuPont for an aqueous solution of 30 weight percent SiO.sub.2 and 0.1 weight percent Na.sub.2 0;
(d) Co(Ac).sub.2 : cobalt acetate Co(C.sub.2 H.sub.3 O.sub.2).sub.2.4H.sub.2 O;
(e) CoSO.sub.4 : cobalt sulfate (CoSO.sub.4.7H.sub.2 O);
(f) H.sub.3 PO.sub.4 : 85 weight percent phosphoric acid in water;
(g) TBAOH: tetrabutylammonium hydroxide (25 wt % in methanol);
(h) Pr.sub.2 NH: di-n-propylamine, (C.sub.3 H.sub.7).sub.2 NH;
(i) Pr.sub.3 N: tri-n-propylamine, (C.sub.3 H.sub.7).sub.3 N;
(j) Quin: Quinuclidine (C.sub.7 H.sub.13 N);
(k) MQuin: Methyl Quinuclidine hydroxide, (C.sub.7 H.sub.13 NCH.sub.3 OH);
(l) C-hex; cyclohexylamine;
(m) TEAOH; tetraethylammonium hydroxide (40 wt. % in water);
(n) DEEA: diethanolamine;
(o) TPAOH: tetrapropylammonium hydroxide (40 wt. % in water); and
(p) TMAOH: tetramethylammonium hydroxide (40 wt. % in water).
Preparative Procedure
The CoAPSO compositions were prepared by preparing reaction mixtures having a molar composition expressed as:
eR:fCoO:hAl.sub.2 O.sub.3 :iP.sub.2 O.sub.5 :gSiO.sub.2 jH.sub.2 O
wherein e, f, h, i, g and j represent the moles of template R, cobalt (expressed as the oxide), Al,.sub.2 O.sub.3, P.sub.2 O.sub.5 (H.sub.3 PO.sub.4 expressed as P.sub.2 O.sub.5), SiO.sub.2 and H.sub.2 O, respectively.
The reaction mixtures were prepared by forming a starting reaction mixture comprising the H.sub.3 PO.sub.4 and one half of the water. This mixture was stirred and the aluminum source (Alipro or CATAPAL) added. The resulting mixture was blended until a homogeneous mixture was observed. The LUDOX-LS was then added to the resulting mixture and the new mixture blended until a homogeneous mixture was observed. The cobalt source (Co(Ac).sub.2, Co(SO.sub.4) or mixtures thereof) was dissolved in the remaining water and combined with the first mixture. The combined mixture was blended until a homogeneous mixture was observed. The organic templating agent was added to this mixture and blended for about two to four minutes until a homogeneous mixture was observed. The resulting mixture (final reaction mixture) was placed in a lined (polytetrafluoroethylene) stainless steel pressure vessel and digested at a temperature (150.degree. C., 200.degree. C. or 225.degree. C.) for time. Alternatively, if the digestion temperature was 100.degree. C. the final reaction mixture was placed in a lined (polytetrafluoroethylene) screw top bottle for a time. All digestions were carried out at the autogenous pressure. The products were removed from the reaction vessel, cooled and evaluated.
ZnAPSO Molecular Sieves
The ZnAPSO molecular sieves of U.S. Ser. No. 600,170, filed Apr. 13, 1984 comprise framework structures of ZnO.sub.2.sup.-2, AlO.sub.2.sup.-, PO.sub.2.sup.+ and SiO.sub.2 tetrahedral units having an empirical chemical composition on an anhydrous basis expressed by the formula:
mR:(Zn.sub.w Al.sub.x P.sub.y Si.sub.z)O.sub.2
wherein "R" represents at least one organic templating agent present in the intracrystalline pore system; "m" represents the molar amount of "R" present per mole of (Zn.sub.w Al.sub.x P.sub.y Si.sub.z)O.sub.2 and has a value of zero to about 0.3; and "w", "x", "y" and "z" represent the mole fractions of zinc, aluminum, phosphorus and silicon, respectively, present as tetrahedral oxides and each has a value of at least 0.01. The mole fractions "w", "x", "y" and "z" are generally defined being within the limiting compositional values or points as follows:
______________________________________ Mole FractionPoint x y (z + w)______________________________________A 0.60 0.38 0.02B 0.38 0.60 0.02C 0.01 0.60 0.39D 0.01 0.01 0.98E 0.60 0.01 0.39______________________________________
In a preferred subclass of ZnAPSO molecular sieves the values "w", "x", "y" and "z" in the above formula are within the limiting compositional values or points as follows:
______________________________________ Mole FractionPoint x y (z + w)______________________________________a 0.55 0.43 0.02b 0.43 0.55 0.02c 0.10 0.55 0.35d 0.55 0.10 0.35______________________________________
ZnAPSO compositions are generally synthesized by hydrothermal crystallization at effective process conditions from a reaction mixture containing active sources of zinc, silicon, aluminum and phosphorus, preferably an organic templating, i.e., structure-directing, agent, preferably a compound of an element or Group VA of the Periodic Table, and/or optionally an alkali of other metal. The reaction mixture is generally placed in a sealed pressure vessel, preferably lined with an inert plastic material such as polytetrafluoroethylene and heated, preferably under autogenous pressure at a temperature between 50.degree. C. and 250.degree. C., and preferably between 100.degree. C. and 200.degree. C. until crystals of the ZnAPSO product are obtained, usually a period of from several hours to several weeks. Generally the effective crystallization period is from about 2 hours to about 30 days with typical periods of from about 4 hours to about 20 days being employed to obtain ZnAPSO products. The product is recovered by any convenient method such as centrifugation or filtration.
In synthesizing the ZnAPSO compositions, it is preferred to employ a reactionmixture composition expressed in terms of the molar ratios as follows:
aR:(Zn.sub.w Al.sub.x P.sub.y Si.sub.z)O.sub.2 : bH.sub.2 O
wherein "R" is an organic templating agent; "a" is the amount of organic templating agent "R" and has a value of from zero to about 6 and is preferably an effective amount within the range of greater than zero (0) to about 6; "b" has a value of from zero (0) to about 500, more preferably between about 2 and about 300; and "w", "x", "y" and "z" represent the mole fractions of zinc, aluminum, phosphorus and silicon, respectively, and each has a value of at least 0.01. In a preferred embodiment the reaction mixture is selected such that the mole fractions "w", "x", "y" and "z" are generally defined as being within the limiting compositional values or points as follows:
______________________________________ Mole FractionPoint x y (z + w)______________________________________F 0.60 0.38 0.02G 0.38 0.60 0.02H 0.01 0.60 0.39I 0.01 0.01 0.98J 0.60 0.01 0.39______________________________________
In the foregoing expression of the reaction composition, the reactants are normalized with respect to the total of "w", "x", "y" and "z" such that (w+x+y+z)=1.00 mole. Molecular sieves containing zinc, aluminum, phosphorus and silicon as framework tetrahedral oxide units are prepared as follows:
Preparative Reagents
ZnAPSO compositions were prepared using numerous reagents. The reagents employed and abbreviations employed herein, if any, for such reagents are as follows:
(a) Alipro: aluminum isopropoxide;
(b) LUDOX-LS: LUDOX-LS is the trade name of DuPont for an aqueous solution of 30 weight percent SiO.sub.2 and 0.1 weight percent Na.sub.2 O;
(c) CATAPAL: Trademark of Condea Corporation for hydrated pseudoboehmite;
(d) H.sub.3 PO.sub.4 : 85 weight percent aqueous phosphoric acid;
(e) ZnAc: Zinc Acetate, Zn(C.sub.2 H.sub.3 O.sub.2).sub.2.4H.sub.2 O;
(f) TEAOH: 40 weight percent aqueous solution of tetraethylammonium hydroxide;
(g) TBAOH: 40 weight percent aqueous solution of tetrabutylammonium hydroxide;
(h) TMAOH: Tetramethylammonium hydroxide pentahydrate, (CH.sub.3).sub.4 NOH.5H.sub.2 O;
(i) TPAOH: 40 weight percent aqueous solution of tetrapropylammonium hydroxide, (C.sub.3 H.sub.7).sub.4 NOH;
(j) Pr.sub.2 NH: di-n-propylamine, (C.sub.3 H.sub.7).sub.2 NH;
(k) Pr.sub.3 N: Tri-n-propylamine, (C.sub.3 H.sub.7).sub.3 N;
(l) Quin: Quinuclidine, (C.sub.7 H.sub.13 N);
(m) C-hex: cyclohexylamine; and
(n) DEEA: diethylethanolamine, (C.sub.2 H.sub.5).sub.2 NC.sub.2 H.sub.5 OH.
Preparative Procedure
The ZnAPSO compositions were prepared by preparing reaction mixtures having a molar composition expressed as:
eR:fZnO:gAl.sub.2 O.sub.3 :hP.sub.2 O.sub.5 : iSiO.sub.2 :jH.sub.2 O
wherein e, f, g, h, i and j represent the moles of template R, zinc (expressed as the oxide), Al.sub.2 O.sub.3, P.sub.2 O.sub.5 (H.sub.3 PO.sub.4 expressed as P.sub.2 O.sub.5), SiO.sub.2 and H.sub.2 O, respectively.
The reaction mixtures were prepared by forming a starting reaction mixture comprising the H.sub.3 PO.sub.4 and a portion of the water. This mixture was stirred and the aluminum source added. The resulting mixture was blended until a homogeneous mixture was observed. The LUDOX LS was then added to the resulting mixture and the new mixture blended until a homogeneous mixture was observed. The zinc source (zinc acetate) was dissolved in the remaining water and combined with the first mixture. The combined mixture was blended until a homogenous mixture was observed. The organic templating agent was added to this mixture and blended for about two to four minutes until a homogenous mixture was observed. The resulting mixture (final reaction mixture) was placed in a lined (polytetrafluoroethylene) stainless steel pressure vessel and digested at an effective temperature for an effective time. All digestions were carried out at the autogenous pressure. The products were removed from the reaction vessel, cooled and evaluated.
FeAPSO Molecular Sieves
The FeAPSO of U.S. Ser. No. 600,173, filed Apr. 13, 1984 have molecular sieves having a three-dimensional microporous crystal framework structures of FeO.sub.2.sup.-2, (and/or FeO.sub.2.sup.-), AlO.sub.2.sup.-, PO.sub.2.sup.+ and SiO.sub.2 tetrahedral oxide units and having a unit empirical formula, on an anhydrous basis, of:
mR:(Fe.sub.w Al.sub.x P.sub.y Si.sub.z)O.sub.2 (1)
wherein "R" represents at least one organic templating agent present in the intracrystalline pore system; "m" represents the moles of "R" present per mole of (Fe.sub.w Al.sub.x P.sub.y Si.sub.z)O.sub.2 and has a value of from zero (0) to about 0.3; the maximum value of "m" in each case depends upon the molecular dimensions of the templating agent and the available void volume of the pore system of the particular molecular sieve involved; and "w" , "x", "y" and "z" represent the mole fractions of iron, aluminum, phosphorus and silicon, respectively, present as tetrahedral oxides, said mole fractions being such that they are within the limiting compositional values or points as follows:
______________________________________ Mole FractionPoint x y (z + w)______________________________________A 0.60 0.38 0.02B 0.38 0.60 0.02C 0.01 0.60 0.39D 0.01 0.01 0.98E 0.60 0.01 0.39______________________________________
The values of w, x, y and z may be as follows:
______________________________________ Mole FractionPoint x y (z + w)______________________________________a 0.55 0.43 0.02b 0.43 0.55 0.02c 0.10 0.55 0.35d 0.55 0.10 0.35______________________________________
The FeAPSOs of the instant invention are generally synthesized by hydrothermal crystallization from a reaction mixture comprising reactive sources of iron, aluminum, phosphorus and silicon, and preferably one or more organic templating agents. Optionally, alkali or other metal(s) may be present in the reaction mixture and may act as templating agents. The reaction mixture in generally placed in a pressure vessel, preferably lined with an inert plastic material, such as polytetrafluoroethylene, and heated, preferably under the autogenous pressure, at an effective temperature which is generally between about 50.degree. C., and about 250.degree. C. and preferably between about 100.degree. C. and 200.degree. C. until crystals of the FeAPSO product are obtained, usually a period of from several hours to several weeks. Molecular sieves containing iron, aluminum phosphorus and silicon as framework tetrahedral oxide units are prepared as follows:
Preparative Reagents
FeAPSO compositions were prepared using numerous reagents. The reagents employed and abbreviations employed herein, if any, for such reagents are as follows:
(a) Alipro: aluminum isopropoxide, Al(OCH(CH.sub.3).sub.2).sub.3 ;
(b) LUDOX-LS: LUDOX-LS is the trademark of Du Pont for an aqueous solution of 30 weight percent SiO.sub.2 and 0.1 weight percent Na.sub.2 O;
(c) CATAPAL: trademark for hydrated aluminum oxide containing about 75 wt. % Al.sub.2 O.sub.3 (pseudo-boehmite phase) and about 25 wt. percent water.
(c) Fe(Ac).sub.2 : Iron (II) acetate; (d) FeSO.sub.4 : Iron (II) sulfate hexahydrate;
(e) H.sub.3 PO.sub.4 : 85 weight percent phosphoric acid in water;
(f) TEAOH: 40 weight percent aqueous solution of tetraethylammonium hydroxide;
(g) TBAOH: 40 weight percent aqueous solution of tetrabutylammonium hydroxide;
(h) Pr.sub.2 NH; di-n-propylamine ((C.sub.3 H.sub.7).sub.2 NH);
(i) Pr.sub.3 N: tri-n-propylamine ((C.sub.3 H.sub.7).sub.3 N);
(j) Quin: Quinuclidine (C.sub.7 H.sub.13 N);
(k) MQuin: Methyl Quinuclidine hydroxide (C.sub.7 H.sub.13 NCH.sub.3 OH);
(l) TMAOH: tetramethylammonium hydroxide pentahydrate; and
(m) C-hex; cyclohexylamine.
(a) Examples were carried out to demonstrate the preparation of FeAPSO-34 and FeAPSO-5. The reaction mixtures were prepared by grinding the aluminum isopropoxide in a blender followed by slowly adding the H.sub.3 PO.sub.4 solution with mixing. A solution/dispersion of iron acetate in water was added and then the LUDOX-LS was added. The organic templating agent was then added to this mixture, or in some cases one-half of this mixture, and the mixture blended to form a homogeneous mixture. The number of moles of each component in the reaction mixture was as follows:
______________________________________ Component Moles______________________________________ Al.sub.2 O.sub.3 0.9 P.sub.2 O.sub.5 0.9 SiO.sub.2 0.2** FeO* 0.2 TEAOH 1.0 H.sub.2 O 50______________________________________ *Iron (II) acetate reported as Iron (II) oxide. **SiO.sub.2 was 0.6 in examples 5C to 8C
Each reaction mixture was sealed in a stainless steel pressure vessel lined with polytetrafluoroethylene and heated in an oven at a temperature, time and at the autogenous pressure. The solid reaction product was recovered by filtration, washed with water and dried at room temperature.
(b) Examples were carried out to demonstrate the preparation of FeAPSO-11 and FeAPSO-5. The reaction mixtures were prepared by grinding the aluminum iso-propoxide in a blender followed by addition of a solution/dispersion of iron (II) acetate. H.sub.3 PO.sub.4 was added to this mixture and the resulting mixture blended to form a homogeneous mixture. LUDOX-LS was added to this mixture except that in some examples the LUDOX-LS was added with the H.sub.3 PO.sub.4. The resulting mixtures were blended until a homogeneous mixture was observed. Organic templating agent was added to each mixture and the resulting mixtures placed in a stainless steel pressure vessel lined with polytetrafluoroethylene and heated, washed and the product recovered as in part (a) of this example. The products were analyzed. The number of moles of each component in the reaction mixture was as follows:
______________________________________ Component Moles______________________________________ Al.sub.2 O.sub.3 0.9 P.sub.2 O.sub.5 0.9 SiO.sub.2 0.2 FeO* 0.2 Template 1.0 H.sub.2 O 50______________________________________ *Iron (II) acetate reported as Iron (II) oxide.
CoMnAPSO Molecular Sieves
The expressed by the empirical chemical formula (anhydrous):
mR:(Co.sub.u Mn.sub.v Al.sub.x P.sub.y Si.sub.z)O.sub.2
where "u", "v", "x", "y" and "z" represent the mole. The CoMnAPSO molecular sieves have an empirical chemical composition on an anhydrous basis expressed by the formula:
mR:(Co.sub.u Mn.sub.v Al.sub.x P.sub.y Si.sub.z)O.sub.2
wherein "R" represents at least one organic templating agent present in the intracrystalline pore system; "m" represents the molar amount of "R" present per mole of (Co.sub.u Mn.sub.v Al.sub.x P.sub.y Si.sub.z)O.sub.2 from zero (0) to about 0.3; and "u", "v", "x", "y" and "z" represent the mole fractions of cobalt, manganese, aluminum, phosphorus and silicon, respectively, present as tetrahedral oxides. The mole fractions "u", "v", "x", "y", and "z" are generally defined as being within the limiting compositional values or points as follows, wherein "w", the combined mole fractions of manganese and cobalt, is the sum of "u" and "v";
______________________________________ Mole FractionPoint x y (z + w)______________________________________A 0.60 0.37 0.03B 0.37 0.60 0.03C 0.01 0.60 0.39D 0.01 0.01 0.98E 0.60 0.01 0.39______________________________________
Preferably the mole fractions u, v, x, y and z will fall within the limiting compositional values or points as follows:
______________________________________Mole Fractionx y (z + w)______________________________________a 0.55 0.42 0.03b 0.42 0.55 0.03c 0.10 0.55 0.35d 0.55 0.10 0.35______________________________________
CoMnAPSO compositions are generally synthesized by hydrothermal crystallization from a reaction mixture containing reactive sources of cobalt, manganese, aluminum, phosphorus and silicon and preferably an organic templating agent, i.e., structure-directing, agent. The structure-directing agents are preferably a compound of an element of Group VA of the Periodic Table, and may be an alkali or other metal. The reaction mixture is generally placed in a sealed pressure vessel, preferably lined with an inert plastic material such as polytetrafluoroethylene and heated, preferably under autogenous pressure and at typical effective temperatures between 50.degree. C. and 250.degree. C., preferably between 100.degree. C. and 200.degree. C., until crystals of the CoMnAPSO product are obtained, usually over a period of from several hours to several weeks. Typical effective crystallization times are from about 2 hours to 30 days with from about 4 hours to about 20 days being generally employed to obtain CoMnAPSO products. The product is recovered by any convenient method such as centrifugation or filtration.
In synthesizing the CoMnAPSO compositions, it is preferred to employ a reaction mixture composition expressed in terms of the molar ratios as follows:
aR:(Co.sub.u Mn.sub.v Al.sub.x P.sub.y Si.sub.z)O.sub.2 :bH.sub.2 O
wherein "R" is an organic templating agent; "a" is the amount of organic templating agent "R" and has a value of from zero to about 6 and is preferably an effective amount within the range of greater than zero (0) to about 6; "b" has a value of from zero (0) to about 500, preferably between about 2 and about 300; and "u", "v", "x", "y", and "z" represent the mole fractions of elements cobalt, manganese, aluminum, phosphorus and silicon, respectively, and each has a value of at least 0.01.
In a preferred embodiment the reaction mixture is selected such that the mole fractions "w", "x", "y" and "z" are generally defined as being within the limiting compositional values or points as follows:
______________________________________Mole Fractionx y (z + w)______________________________________F 0.60 0.37 0.03G 0.37 0.60 0.03H 0.01 0.60 0.39I 0.01 0.01 0.98J 0.60 0.01 0.39______________________________________
In the foregoing expression of the reaction composition, the reactants are normalized with respect to the total of "u", "v", "x", "y" and "z" such that (u+v+x+y+z)=1.00 mole. CoMnAPSO compositions were prepared using numerous regents. The reagents employed and abbreviations employed herein, if any, for such reagents are as follows:
(a) Alipro: aluminum isopropoxide;
(b) LUDOX-LS: LUDOX-LS is the tradename of DuPont for an aqueous solution of 30 weight percent SiO.sub.2 and 0.1 weight percent Na.sub.2 O;
(c) H.sub.3 PO.sub.4 : 85 weight percent phosphoric acid;
(d) MnAc: Manganese acetate, Mn(C.sub.2 H.sub.3 O.sub.2).sub.2.4H.sub.2 O;
(e) CoAc: Cobalt Acetate, Co(C.sub.2 H.sub.3 O.sub.2).sub.2.4H.sub.2 O;
(f) TEAOH: 40 weight percent aqueous solution of tetraethylammonium hydroxide; and
(g) Pr.sub.2 NH: di-n-propylamine, (C.sub.3 H.sub.7).sub.2 NH.
Preparative Procedures
Preparative examples were carried out by forming a starting reaction mixture by adding the H.sub.3 PO.sub.4 and one half of the quantity of water. To this mixture the aluminum isopropoxide was added. This mixture was then blended until a homogeneous mixture was observed. To this mixture the LUDOX-LS was added and the resulting mixture blended (about 2 minutes) until a homogeneous mixture was observed. A second mixture was prepared using manganese acetate and one half of the remaining water. A third mixture was prepared using cobalt acetate and one half of the remaining water. The three mixtures were admixed and the resulting mixture blended until a homogeneous mixture was observed. The organic templating agent was then added to the resulting mixture and the resulting mixture blended until a homogeneous mixture was observed, i.e., about 2 to 4 minutes. The pH of the mixture was measured and adjusted for temperature. The mixture was then placed in a lined (polytetrafluoroethylene) stainless steel pressure vessel and digested at a temperature All digestions were carried out at the autogenous pressure.
CoMnMgAPSO Molecular Sieves
The CoMnMgAPSO molecular sieves of U.S. Ser. No. 600,182, filed Apr. 13, 1984 have three-dimensional microporous framework structures of CoO.sub.2.sup.-2, MnO.sub.2.sup.-2, MgO.sub.2.sup.-2, AlO.sub.2.sup.-, PO.sub.2.sup.+ and SiO.sub.2 tetrahedral oxide units and have an empirical chemical composition on an anhydrous basis expressed by the formula:
mR:(Co.sub.t Mn.sub.u Mg.sub.v Al.sub.x P.sub.y Si.sub.z)O.sub.2
wherein "R" represents at least one organic templating agent present in the intracrystalline pore system; "m" represents the molar amount of "R" present per mole of (Co.sub.t Mn.sub.u Mg.sub.v Al.sub.x P.sub.y Si.sub.z)O.sub.2, and has a value of from zero to about 0.3; and "t", "u", "v", "x", "y" and "z" represent the mole fractions of cobalt, manganese, magnesium, aluminum, phosphorus and silicon, respectively, present as tetrahedral oxides, each having a value of at least 0.01. The mole fractions "t", "u", "v", "x", "y" and "z" are generally defined as being within the limiting compositional values or points as follows, wherein "w", the combined mole fractions of cobalt, manganese and magnesium, is the sum of "t", "u" and "v":
______________________________________Mole FractionPoint x y (z + w)______________________________________A 0.60 0.36 0.04B 0.36 0.60 0.04C 0.01 0.60 0.39D 0.01 0.01 0.98E 0.60 0.01 0.39______________________________________
In a preferred subclass of the CoMnMgAPSO molecular sieves the values of "w", "x", "y" and "z" in the above formula are within the limiting compositional values or points as follows:
______________________________________Mole FractionPoint x y (z + w)______________________________________a 0.55 0.41 0.04b 0.41 0.55 0.04c 0.10 0.55 0.35d 0.55 0.10 0.35______________________________________
The CoMnMgAPSOs of this invention are useful as adsorbents, catalysts, ion-exchangers, and the like in much the same fashion as aluminosilicates have been employed heretofore, although their chemical and physical properties are not necessarily similar to those observed for aluminosilicates.
CoMnMgAPSO compositions are generally synthesized by hydrothermal crystallization from a reaction mixture containing reactive sources of cobalt, manganese, magnesium, aluminum, phosphorus and silicon, and preferably an organic templating agent, i.e., structure-directing, agent. The structure-directing agents are preferably a compound of an element of Group VA of the Periodic Table, and/or optionally an alkali or other metal. The reaction mixture is generally placed in a sealed pressure vessel, preferably lined with an inert plastic material such as polytetrafluoroethylene and heated, preferably under autogenous pressure at a temperature between 50.degree. C. and 250.degree. C., and preferably between 100.degree. C. and 200.degree. C. until crystals of the CoMnMgAPSO product are obtained, usually over a perod of from several hours to several weeks. Typical crystallization times are from about 2 hours to about 30 days with from about 4 hours to about 20 days generally being employed to obtain CoMnMgAPSO products. The product is recovered by any convenient method such as centrifugation or filtration.
In synthesizing the CoMnMgAPSO compositions, it is preferred to employ a reaction mixture composition expressed in terms of the molar ratios as follows:
aR:(Co.sub.t Mn.sub.u Mg.sub.v Al.sub.x P.sub.y Si.sub.z)O.sub.2 :bH.sub.2 O
wherein "R" is an organic templating agent; "a" is the amount of organic templating agent "R" and has a value of from zero to about 6 and is preferably an effective amount within the range of greater than zero (0) to about 6 and more preferably from greater than zero to about 2; "b" has a value of from zero (0) to about 500, preferably between about 2 and about 300; and "t", "u", "v", "x", "y", and "z" represent the mole fractions of cobalt, manganese, magnesium, aluminum, phosphorus and silicon, respectively, and each has a value of at least 0.01.
In a preferred embodiment the reaction mixture is selected such that the mole fractions "w", "x", "y" and "z", where "w" is the sum of "t"+"u"+"v", are generally defined as being within the limiting compositional values or points as follows:
______________________________________Mole FractionPoint x y (z + w)______________________________________F 0.60 0.36 0.04G 0.36 0.60 0.04H 0.01 0.60 0.39I 0.01 0.01 0.98J 0.60 0.01 0.39______________________________________
In the foregoing expression of the reaction composition, the reactants are normalized with respect to the total of "t", "u", "v", "x", "y" and "z" such that (t+u+v+x+y+z)=1.00 mole. Molecular sieves containing cobalt, manganese, magnesium, aluminum, phosphorus and silicon as framework tetrahedral oxide units are prepared as follows:
Preparative Reagents
CoMnMgAPSO compositions were prepared using numerous reagents. The reagents employed and abbreviations employed herein, if any, for such reagents are as follows:
(a) Alipro: aluminum isopropoxide;
(b) LUDOX-LS: LUDOX-LS is the tradename of Du Pont for an aqueous solution of 30 weight percent SiO.sub.2 and 0.1 weight percent Na.sub.2 O;
(c) H.sub.3 PO.sub.4 : aqueous solution which is 85 weight percent phosphoric acid;
(d) MnAc: Manganese acetate, Mn(C.sub.2 H.sub.3 O.sub.2).sub.2.4H.sub.2 O;
(e) CoAc: Cobalt Acetate, Co(C.sub.2 H.sub.3 O.sub.2).sub.2.4H.sub.2 O;
(f) MgAc: Magnesium Acetate Mg(C.sub.2 H.sub.3 O.sub.2).4H.sub.2 O;
(g) TEAOH: 40 weight percent aqueous solution of tetraethylammonium hydroxide; and
(h) Pr.sub.2 NH: di-n-propylamine, (C.sub.3 H.sub.7).sub.2 NH.
Preparative Procedures
Preparative examples were carried out by forming a starting reaction mixture by adding the H.sub.3 PO.sub.4 and one half of the quantity of water. To this mixture the aluminum isoproxide was added. This mixture was then blended until a homogeneous mixture was observed. To this mixture the LUDOX-LS was added and the resulting mixture blended (about 2 minutes) until a homogeneous mixture was observed.
Three additional mixtures were prepared using cobalt acetate, magnesium acetate and manganese acetate using one third of the remainder of the water for each mixture. The four mixtures were then admixed and the resulting mixture blended until a homogeneous mixture was observed. The organic templating agent was then added to the resulting mixture and the resulting mixture blended until a homogeneous mixture was observed, i.e., about 2 to 4 minutes. The mixture was then placed in a lined (polytetrafluoroethylene) stainless steel pressure vessel and digested at a temperature for a time. All digestions were carried out at the autogenous pressure.
SAPO Molecular Sieves
The silicoaluminophosphate molecular sieves of U.S. Pat. No. 4,440,871 are microporous crystalline silicoaluminophosphates the pores of which are uniform and have nominal diameters of greater than about 3 Angstroms and whose essential empirical chemical composition in the as-synthesized and anhydrous form is
mR:(Si.sub.x Al.sub.y P.sub.z)O.sub.2
wherein "R" represents at least one organic templating agent present in the intracrystalline pore system; "m" represents the moles of "R" present per mole of (Si.sub.x Al.sub.y P.sub.z)O.sub.2 ; "m" has a value of from 0.02 to 0.3; "x", "y" and "z" represent the mole fractions of silicon, aluminum and phosphorus respectively, present as tetrahedral oxides, said mole fractions being such that they are within the pentagonal compositional area defined by points ABCD and E of the ternary diagram which is FIG. 1 of the drawings of U.S. Pat. No. 4,440,871. The SAPO molecular sieves of U.S. Pat. No. 4,440,871 are also described as silicoaluminophosphates having a three-dimensional microporous framework structure of PO.sub.2.sup.+, AlO.sub.2.sup.- and SiO.sub.2 tetrahedral units, and whose essential empirical chemical composition on an anhydrous basis is:
mR:(Si.sub.x Al.sub.y P.sub.z)O.sub.2
wherein "R" represents at least one organic templating agent present in the intracrystalline pore system; "m" represents the moles of "R" present per mole of (Si.sub.x Al.sub.y P.sub.z)O.sub.2 and has a value of from zero to 0.3; "x", "y" and "z" represent respectively, the mole fractions of silicon, aluminum and phosphorus present in the oxide moiety, said mole fractions being within the compositional area bounded by points A, B, C, D and E on the ternary diagram which is FIG. 1, said silicoaluminophosphate having a characteristic X-ray powder diffraction pattern which contains at least the d-spacings set forth below in any one of Tables I, III, V, VII, IX, XII, XVII, XXI, XXIII or XXV of U.S. Pat. No. 4,440,871. Further, such crystalline silicoaluminophosphates may be calcined at a temperature sufficiently high to remove at least some of any organic templating agent present in the intracrystalline pore system. The silicoaluminophosphates of U.S. Pat. No. 4,440,871 are generally referred to therein as "SAPO-n", as a class, or as "SAPO-n" wherein "n" is an integer denoting a particular SAPO as its preparation is reported in U.S. Pat. No. 4,440,871.
MeAPO MOLECULAR SIEVES
There has now been discovered a novel class of framework-substituted crystalline microporous aluminophosphates in which the substituent metal is one of a mixture of two or more divalent metals of the group magnesium, manganese, zinc and cobalt, and which exhibit adsorption, ion-exchange and/or catalytic properties similar to the prior known aluminosilicate, aluminophosphate and silicoaluminophosphate molecular sieve compositions. Members of this novel class of compositions have a three-dimensional microporous crystal framework structure of MO.sub.2.sup.-2, AlO.sub.2.sup.- and PO.sub.2.sup.+ tetrahedral units and have an essential empirical chemical composition, on an anhydrous basis, of:
mR:(M.sub.x Al.sub.y P.sub.z)O.sub.2
wherein "R" represents at least one organic templating agent present in the intracrystalline pore system; "m" represents the moles of "R" present per mole of (M.sub.x Al.sub.y P.sub.z)O.sub.2 and has a value of from zero to 0.3, the maximum value in each case depending upon the molecular dimensions of the templating agent and the available void volume of the pore system of the particular metal aluminophosphate involved; "x", "y", and "z" represent the mole fractions of the metal "M", (i.e., magnesium, manganese, zinc and cobalt), aluminum and phosphorus, respectively, present as tetrahedral oxides, said mole fractions being such that they are representing the following values for "x", "y", and "z":
______________________________________Mole FractionPoint x y z______________________________________A 0.01 0.60 0.39B 0.01 0.39 0.60C 0.35 0.05 0.60D 0.35 0.60 0.05______________________________________
When synthesized in accordance with the novel process of the present invention, the minimum value of "m" in the formula above is 0.02. In a preferred subclass of the metal aluminophosphates of this invention, the values of "x", "y" and "z" in the formula above are representing the following values for "x", "y" and "z":
______________________________________Mole FractionPoint x y z______________________________________a 0.01 0.52 0.47b 0.01 0.39 0.60c 0.25 0.15 0.60d 0.25 0.40 0.35______________________________________
The metal aluminophosphates of this new class of compositions exhibit molecular sieving properties, and, in common with zeolitic aluminosilicates, are capable of reversibly adsorbing water and other molecular species. Many are capable of reversibly undergoing complete dehydration without loss or change in crystal structure. All of the as-synthesized compositions of this invention are capable of withstanding 350.degree. C. calcination in air for extended periods, i.e., at least 2 hours, without becoming amorphous. While it is believed that the M, Al and P framework constituents are present in tetrahedral coordination with oxygen, it is theoretically possible that some minor fraction of these framework constituents are present in coordination with five or six oxygen atoms. It is not, moreover necessarily the case that all of the M, Al and/or P content of any given synthesized product be a part of the framework in the aforesaid types of coordination with oxygen. Some of each constituent may be merely occluded or in some as yet undetermined form and may or may not be structurally significant.
Since the term "metal aluminophosphate" is somewhat cumbersome, particularly in view of the need for numerous repetitions thereof in describing the compositions of the present invention in this specification, the "short-hand" reference "MeAPO" is sometimes employed hereinafter. Also in those cases where the metal "Me" in the composition is magnesium, the acronym MAPO is applied to the composition. Similarly, ZAPO, MnAPO, and CoAPO are applied to the compositions which contain zinc, manganese and cobalt, respectively. To identify the various structural species which make up each of the subgeneric classes MAPO, ZAPO, CoAPO and MnAPO, each species is assigned a number and is identified, for example, as ZAPO-5, MAPO-11, CoAPO-34 and so forth.
The term "essential empirical chemical composition" is meant to include the crystal framework and can include any organic templating agent present in the pore system, but does not include alkali metal or other ions which can be present by virtue of being contained in the reaction mixture or as a result of post-synthesis ion-exchange. Such ionic species, when present, function primarily as charge-balancing ions for AlO.sub.2.sup.- and/or MO.sub.2.sup.-2 tetrahedra not associated with PO.sub.2.sup.+ tetrahedra or an organic ion derived from the organic templating agent.
The aforesaid novel metal aluminophosphates are synthesized by hydrothermal crystallization from a reaction mixture containing reactive sources of the metal "M", alumina and phosphate, an organic templating, i.e., structure-directing, agent, preferably a compound of an element of Group VA of the Periodic Table, and optionally an alkali metal. The reaction mixture is placed in a sealed pressure vessel, preferably lined with an inert plastic material such as polytetrafluoroethylene and heated, preferably under autogenous pressure at a temperature between 100.degree. C. and 225.degree. C., and preferably between 100.degree. C. and 200.degree. C. until crystals of the metal aluminophosphate product are obtained, usually a period of from 4 hours to 2 weeks. The product is recovered by any convenient method such as centrifugation or filtration.
In synthesizing the MeAPO compositions of the present invention, it is preferred to employ a reaction mixture composition expressed in terms of molar ratios as follows:
aR:(M.sub.x Al.sub.y P.sub.z)O.sub.2 :bH.sub.2 O
wherein "R" is an organic templating agent; "a" has a value great enough to constitute an effective concentration of "R" and is within the range of >0 to 6; "b" has a value of from zero to 500, preferably 2 to 30; "M" represents a metal of the group zinc, magnesium, manganese and cobalt, "x", "y" and "z" represent the mole fractions, respectively, of "M", aluminum and phosphorus in the (M.sub.x Al.sub.y P.sub.z)O.sub.2 constituent, and each has a value of at least 0.01, the said points E, F, G, H, I, and J representing the following values for "x", "y" and "z":
______________________________________Mole FractionPoint x y z______________________________________E 0.01 0.70 0.29F 0.01 0.29 0.70G 0.29 0.01 0.70H 0.40 0.01 0.59I 0.40 0.59 0.01J 0.29 0.70 0.01______________________________________
In the foregoing expression of the reaction composition, the reactants are normalized with respect to a total of (M+Al+P)=(x+y+z)=1.00 mole.
In forming the reaction mixture from which the present metal aluminophosphates are crystallized the organic templating agent can be any of those heretofore proposed for use in the synthesis of conventional zeolite aluminosilicates and microporous aluminophosphates. In general these compounds contain elements of Group VA of the Periodic Table of Elements, particularly nitrogen, phosphorus, arsenic and antimony, preferably N or P and most preferably N, which compounds also contain at least one alkyl or aryl group having from 1 to 8 carbon atoms. Particularly preferred nitrogen-containing compounds for use as templating agents are the amines and quaternary ammonium compounds, the latter being represented generally by the formula R.sub.4 N.sup.+ wherein each R is an alkyl or aryl group containing from 1 to 8 carbon atoms. Polymeric quaternary ammonium salts such as [(C.sub.14 H.sub.32 N.sub.2)(OH).sub.2 ].sub.x wherein "x" has a value of at least 2 are also suitably employed. Both mono-, di- and triamines are advantageously utilized, either alone or in combination with a quaternary ammonium compound or other templating compound. Mixtures of two or more templating agents can either produce mixtures of the desired metal aluminophosphates or the more strongly directing templating species may control the course of the reaction with the other templating species serving primarily to establish the pH conditions of the reaction gel. Representative templating agents include tetramethylammonium, tetraethylammonium, tetrapropylammonium or tetrabutylammonium ions; di-n-propylamine; tripropylamine; triethylamine; triethanolamine; piperidine; cyclohexylamine; 2-methylpyridine; N,N-dimethylbenzylamine; N-N-dimethylethanolamine; choline; N,N'-dimethylpiperazine; 1,4-diazabicyclo(2,2,2)octane; N-methyldiethanolamine, N-methylethanolamine; N-methylpiperidine; 3-methylpiperidine; N-methylcyclohexylamine; 3-methylpyridine; 4-methylpyridine; quinuclidine; N,N'-dimethyl-1,4-diazabicyclo(2,2,2)octane ion; di-n-butylamine, neopentylamine; di-n-pentylamine; isopropylamine; t-butylamine; ethylenediamine; pyrrolidine; and 2-imidazolidone. Not every templating agent will direct the formation of every species of metal aluminophosphate (MeAPO), i.e., a single templating agent can, with proper manipulation of the reaction conditions, direct the formation of several MeAPO compositions, and a given MeAPO composition can be produced using several different templating agents.
The most suitable phosphorus source yet found for the present process is phosphoric acid, but organic phosphates such as triethylphosphate have been found satisfactory, and so also have crystalline or amorphous aluminophosphates such as the AlPO.sub.4 composition of U.S. Pat. No. 4,310,440. Organo-phosphorus compounds, such as tetrabutylphosphonium bromide do not, apparently serve as reactive sources of phosphorus, but these compounds do function as templating agents. Conventional phosphorus salts such as sodium metaphosphate, may be used, at least in part, as the phosphorus source, but are not preferred.
The preferred aluminum source is either an aluminum alkoxide, such as aluminum isopropoxide, or pseudoboehmite. The crystalline or amorphous aluminophosphates which are a suitable source of phosphorus are, of course, also suitable sources of aluminum. Other sources of aluminum used in zeolite synthesis, such as gibbsite, sodium aluminate and aluminum trichloride, can be employed but are not preferred.
The metals zinc, cobalt, magnesium and manganese can be introduced into the reaction system in any form which permits the formation in situ of reactive divalent ions of the respective metals. Advantageously salts, oxides or hydroxides of the metals are employed such as cobalt chloride hexahydrate, alpha cobaltous iodide, cobaltous sulfate, cobalt acetate, cobaltous bromide, cobaltous chloride, zinc acetate, zinc bromide, zinc formate, zinc iodide, zinc sulfate heptahydrate, magnesium acetate, magnesium bromide, magnesium chloride, magnesium iodide, magnesium nitrate, magnesium sulfate, manganous acetate, manganous bromide, manganous sulfate, and the like.
While not essential to the synthesis of MeAPO compositions, it has been found that in general, stirring or other moderate agitation of the reaction mixture and/or seeding the reaction mixture with seed crystals of either the MeAPO species to be produced or a topologically similar aluminophosphate or aluminosilicate composition, facilitates the crystallization procedure.
After crystallization the MeAPO product is isolated and advantageously washed with water and dried in air. The as-synthesized MeAPO contains within its internal pore system at least one form of the templating agent employed in its formation. Most commonly the organic moiety is present, at least in part, as a charge-balancing cation as is generally the case with as-synthesized aluminosilicate zeolites prepared from organic-containing reaction systems. It is possible, however, that some or all of the organic moiety is an occluded molecular species in a particular MeAPO species. As a general rule, the templating agent, and hence the occluded organic species, is too large to move freely through the pore system of the MeAPO product and must be removed by calcining the MeAPO at temperatures of 200.degree. C. to 700.degree. C. to thermally degrade the organic species. In a few instances the pores of the MeAPO product are sufficiently large to permit transport of the templating agent, particularly if the latter is a small molecule, and accordingly complete or partial removal thereof can be accomplished by conventional desorption procedures such as carried out in the case of zeolites. It will be understood that the term "as-synthesized" as used herein and in the claims does not include the condition of the MeAPO phase wherein the organic moiety occupying the intracrystalline pore system as a result of the hydrothermal crystallization process has been reduced by post-synthesis treatment such that the value of "m" in the composition formula
mR:(M.sub.x Al.sub.y P.sub.z)O.sub.2
has a value of less than 0.02. The other symbols of the formula are as defined hereinabove. In those preparations in which an aluminum alkoxide is employed as the source of aluminum, the corresponding alcohol is necessarily present in the reaction mixture since it is a hydrolysis product of the alkoxide. It has not been determined whether this alcohol participates in the syntheses process as a templating agent. For the purposes of this application, however, this alcohol is arbitrarily omitted from the class of templating agents, even if it is present in the as-synthesized MeAPO material.
Since the present MeAPO compositions are formed from AlO.sub.2, PO.sub.2, and MO.sub.2 tetrahedral units which, respectively, have a net charge of -1, +1, and -2, the matter of cation exchangeability is considerably more complicated than in the case of zeolitic molecular sieves in which, ideally, there is a stoichiometric relationship between AlO.sub.2 tetrahedra and charge-balancing cations. In the MeAPO compositions, an AlO.sub.2.sup.- tetrahedron can be balanced electrically either by association with a PO.sub.2.sup.+ tetrahedron or a simple cation such as an alkali metal cation, a cation of the metal "M" present in the reaction mixture, or an organic cation derived from the templating agent. Similarly an MO.sub.2.sup.-2 tetrahedron can be balanced electrically by association with PO.sub.2.sup.+ tetrahedra, a cation of the metal "M", organic cations derived from the templating agent, or other divalent or polyvalent metal cations introduced from an extraneous source. It has also been postulated that non-adjacent AlO.sub.2.sup.- and PO.sub.2.sup.+ tetrahedral pairs can be balanced by Na.sup.+ and OH.sup.-, respectively [Flanigen and Grose, Molecular Sieve Zeolites-I, ACS, Washington, D.C. (1971)].
In any event, all of the MeAPO compositions of the present invention examined to date have exhibited cation-exchange capacity, in some cases to a significant degree, when analyzed using ion-exchange techniques heretofore employed with zeolitic aluminosilicates. All have uniform pore diameters which are inherent in the lattice structure of each species and which are at least about 3 .ANG. in diameter. Ion exchange is ordinarily possible only after the organic moiety present as a result of synthesis has been removed from the pore system. Dehydration to remove water present in the as-synthesized MeAPO compositions can usually be accomplished, to some degree at least, in the usual manner without removal of the organic moiety, but the absence of the organic species greatly facilitates adsorption and desorption procedures. As illustrated hereinafter, the MeAPO materials have various degrees of hydrothermal and thermal stability, some being quite remarkable in this regard, and function well as molecular sieve adsorbents and hydrocarbon conversion catalyst or catalyst bases.
FeAPSO MOLECULAR SIEVES
There has now been discovered a novel class of framework-substituted crystalline microporous aluminophosphates in which the substituent metal is iron, and which exhibit adsorption, ion-exchange and/or catalytic properties similar to the prior known aluminosilicate, aluminophosphate and silicoaluminophosphate molecular sieve compositions. Members of this novel class of ferroaluminophosphates have a three-dimensional microporous crystal framework structure of AlO.sub.2, FeO.sub.2, and PO.sub.2 tetrahedral units and have an essential empirical chemical composition, on an anhydrous basis, of:
mR:(Fe.sub.x Al.sub.y P.sub.z)O.sub.2
wherein "R" represents at least one organic templating agent present in the intracrystalline pore system; "m" represents the moles of "R" present per mole of (Fe.sub.x Al.sub.y P.sub.z)O.sub.2 and has a value of from zero to 0.3, the maximum value in each case depending upon the molecular dimensions of the templating agent and the available void volume of the pore system of the particular ferroaluminophosphate involved; "x", "y", and "z" represent the mole fractions of iron, aluminum and phosphorus, respectively, present as tetrahedral oxides, representing the following values for "x", "y", and "z":
______________________________________Mole FractionPoint x y z______________________________________A 0.01 0.60 0.39B 0.01 0.39 0.60C 0.35 0.05 0.60D 0.35 0.60 0.05______________________________________
When synthesized in accordance with the novel process of the present invention, the minimum value of "m" in the formula above is 0.02. In a preferred subclass of the ferroaluminophosphates of this invention, the values of "x", "y" and "z" in the formula above are representing the following values for "x", "y" and "z":
______________________________________Mole FractionPoint x y z______________________________________a 0.01 0.52 0.47b 0.01 0.39 0.60c 0.25 0.15 0.60d 0.25 0.40 0.35______________________________________
The iron of the FeO.sub.2 structural units of the present compositions can be in either the ferric or ferrous valence state, depending largely upon the source of the iron in the synthesis gel. Thus, an FeO.sub.2 tetrahedron in the structure can have a net charge of either -1 or -2. While it is believed that the Fe, Al and P framework constituents are present in tetrahedral coordination with oxygen (and are referred to herein as such), it is theoretically possible that some minor fraction of these framework constituents are present in coordination with five or six oxygen atoms. It is not, moreover, necessarily the case that all of the Fe, Al and/or P content of any given synthesized product is a part of the framework in the aforesaid types of coordination with oxygen. Some of each constituent may be merely occluded or in some as yet undetermined form, and may or may not be structurally significant.
The ferroaluminophosphates of this new class of compositions exhibit molecular sieving properties, and, in common with zeolitic aluminosilicates, are capable of reversibly adsorbing water and other molecular species. Many are capable of reversibly undergoing complete dehydration without loss or change in crystal structure.
For convenience in describing the compositions of the present invention in this specification, the "short-hand" acronym "FAPO" is sometimes employed hereinafter. To identify the various structural species which make up the generic class FAPO, each species is assigned a number and is identified, for example, as FAPO-5, FAPO-11, FAPO-34 and so forth.
The term "essential empirical chemical composition" is meant to include the crystal framework and can include any organic templating agent present in the pore system, but does not include alkali metal or other ions which can be present by virtue of being contained in the reaction mixture or as a result of post-synthesis ion-exchange. Such ionic species, when present, function primarily as charge-balancing ions for FeO.sub.2.sup.- and/or AlO.sub.2.sup.-2 tetrahedra, FeO.sub.2.sup.-2 tetrahedra associated with PO.sub.2.sup.+ tetrahedra or not associated with PO.sub.2.sup.+ tetrahedra or an organic ion derived from the organic templating agent.
The aforesaid novel ferroaluminophosphates are synthesized by hydrothermal crystallization from a reaction mixture containing reactive sources of iron oxide, alumina and phosphate, an organic templating, i.e., structure-directing, agent, preferably a compound of an element of Group VA of the Periodic Table, and optionally an alkali metal. The reaction mixture is placed in a sealed pressure vessel, preferably lined with an inert plastic material such as polytetrafluoroethylene and heated, preferably under autogenous pressure at a temperature of at least 100.degree. C., and preferably between 100.degree. C. and 250.degree. C. until crystals of the metal aluminophosphate product are obtained, usually a period of from 2 hours to 2 weeks. The product is recovered by any convenient method such as centrifugation or filtration.
In synthesizing the FAPO compositions of the present invention, it is preferred to employ a reaction mixture composition expressed in terms of molar ratios as follows:
aR:(Fe.sub.x Al.sub.y P.sub.z)O.sub.2 :bH.sub.2 O
ps wherein "R" is an organic templating agent; "a" has a value great enough to constitute an effective concentration of "R" and is within the range of >0 to 6; "b" has a value of from zero to 500, preferably 2 to 80; "x", "y" and "z" represent the mole fractions, respectively, of iron, aluminum and phosphorus in the (Fe.sub.x Al.sub.y P.sub.z)O.sub.2 constituent, and each has a value of at least 0.01, and "z":
______________________________________Mole FractionPoint x y z______________________________________E 0.01 0.70 0.29F 0.01 0.29 0.70G 0.29 0.01 0.70H 0.40 0.01 0.59I 0 40 0.59 0.01J 0.29 0.70 0.01______________________________________
In the foregoing expression of the reaction composition, the reactants are normalized with respect to a total of (Fe+Al+P)=(x+y+z)=1.00 mole.
In forming the reaction mixture from which the present ferroaluminophosphates are crystallized, the organic templating agent can be any of those heretofore proposed for use in the synthesis of conventional zeolite aluminosilicates and microporous aluminophosphates. In general these compounds contain elements of Group VA of the Periodic Table of Elements, particularly nitrogen, phosphorus, arsenic and antimony, preferably N or P and most preferably N, which compounds also contain at least one alkyl or aryl group having from 1 to 8 carbon atoms. Particularly preferred nitrogen-containing compounds for use as templating agents are the amines and quaternary ammonium compounds, the latter being represented generally by the formula R.sub.4 N.sup.+ wherein each R is an alkyl or aryl gorup containing from 1 to 8 carbon atoms. Polymeric quaternary ammonium salts such as [(C.sub.14 H.sub.32 N.sub.2)(OH).sub.2 ].sub.x wherein "x" has a value of at least 2 are also suitably employed. Both mono-, di- and triamines are advantageously utilized, either alone or in combination with a quaternary ammonium compound or other templating compound. Mixtures of two or more templating agents can either produce mixtures of the desired metal aluminophosphates or the more strongly directing templating species may control the course of the reaction with the other templating species serving primarily to establish the pH conditions of the reaction gel. Representative templating agents include tetramethylammonium, tetraethylammonium, tetrapropylammonium or tetrabutylammonium ions; di-n-propylamine; tri-n-propylamine; triethylamine; triethanolamine; piperidine; cyclohexylamine; 2-methylpyridine; N,N-dimethylbenzylamine; N-N-dimethylethanolamine, choline; N,N'-dimethylpiperazine; 1,4-diazabicyclo(2,2,2)octane; N-methyldiethanolamine, N-methylethanolamine; N-methylpiperidine; 3-methylpiperidine; N-methylcyclohexylamine; 3-methylpyridine; 4-methylpyridine; quinuclidine; N,N'-dimethyl-1,4-diazabicyclo(2,2,2)octane ion; di-n-butylamine, neopentylamine; di-n-pentylamine; isopropylamine; t-butylamine; ethylenediamine; pyrrolidine; and 2-imidazolidone. Not every templating agent will direct the formation of every species of ferroaluminophosphate (FAPO), i.e., a single templating agent can, with proper manipulation of the reaction conditions, direct the formation of several FAPO compositions, and a given FAPO composition can be produced using several different templating agents.
The most suitable phosphorus source yet found for the present process is phosphoric acid, but organic phosphates such as triethylphosphate have been found satisfactory, and so also have crystalline or amorphous aluminophosphates such as the AlPO.sub.4 composition of U.S. Pat. No. 4,310,440. Organo-phosphorus compounds, such as tetrabutylphosphonium bromide do not, apparently serve as reactive sources of phosphorus, but these compounds do function as templating agents. Conventional phosphorus salts such as sodium metaphosphate, may be used, at least in part, as the phosphorus source, but are not preferred.
The preferred aluminum source is either an aluminum alkoxide, such as aluminum isopropoxide, or pseudoboehmite. The crystalline or amorphous aluminophosphates which are a suitable source of phosphorus are, of course, also suitable sources of aluminum. Other sources of aluminum used in zeolite synthesis, such as gibbsite, sodium aluminate and aluminum trichloride, can be employed but are not preferred.
Iron can be introduced into the reaction system in any form which permits the formation in situ of reactive ferrous or ferric ions. Advantageously iron salts, oxides or hydroxides are employed such as iron sulfate, iron acetate, iron nitrate, or the like. Other sources such as a freshly precipitated iron oxide .gamma.-FeOOH, are also suitable.
While not essential to the synthesis of FAPO compositions, it has been found that in general, stirring or other moderate agitation of the reaction mixture and/or seeding the reaction mixture with seed crystals of either the FAPO species to be produced or a topologically similar aluminophosphate or aluminosilicate composition, facilitates the crystallization procedure.
After crystallization the FAPO product is isolated and advantageously washed with water and dried in air. The as-synthesized FAPO contains within its internal pore system at least one form of the templating agent employed in its formation. Most commonly the organic moiety is present, at least in part, as a charge-balancing cation as is generally the case with as-synthesized aluminosilicate zeolites prepared from organic-containing reaction systems. It is possible, however, that some or all of the organic moiety is an occluded molecular species in a particular FAPO species. As a general rule, the templating agent, and hence the occluded organic species, is too large to move freely through the pore system of the FAPO product and must be removed by calcining the FAPO at temperatures of 200.degree. C. to 700.degree. C. to thermally degrade the organic species. In a few instances the pores of the FAPO product are sufficiently large to permit transport of the templating agent, particularly if the latter is a small molecule, and accordingly complete or partial removal thereof can be accomplished by conventional desorption procedures such as carried out in the case of zeolites. It will be understood that the term "as-synthesized" as used herein and in the claims does not include the condition of the FAPO phase wherein the organic moiety occupying the intracrystalline pore system as a result of the hydrothermal crystallization process has been reduced by post-synthesis treatment such that the value of "m" in the composition formula
mR:(Fe.sub.x Al.sub.y P.sub.z)O.sub.2
has a value of less than 0.02. The other symbols of the formula are as defined hereinabove. In those preparations in which an aluminum alkoxide is employed as the source of aluminum, the corresponding alcohol is necessarily present in the reaction mixture since it is a hydrolysis product of the alkoxide. It has not been determined whether this alcohol participates in the syntheses process as a templating agent. For the purposes of this application, however, this alcohol is arbitrarily omitted from the class of templating agents, even if it is present in the as-synthesized FAPO material.
Since the present FAPO compositions are formed from AlO.sub.2.sup.-, PO.sub.2.sup.+, FeO.sub.2.sup.- and/or FeO.sub.2.sup.-2 units the matter of cation exchangeability is considerably more complicated than in the case of zeolitic molecular sieves in which, ideally, there is a stoichiometric relationship between AlO.sub.2 tetrahedra and charge-balancing cations. In the FAPO compositions, an AlO.sub.2.sup.- tetrahedron can be balanced electrically either by association with a PO.sub.2.sup.+ tetrahedron or a simple cation such as an alkali metal cation, a Fe.sup.+2 or Fe.sup.+3 cation present in the reaction mixture, or an organic cation derived from the templating agent. Similarly an FeO.sub.2.sup.- or FeO.sub.2.sup.-2 tetrahedron can be balanced electrically by association with PO.sub.2.sup.+ tetrahedron, a Fe.sup.+2 or Fe.sup.+3 cation, organic cations derived from the templating agent, or other metal cation introduced from an extraneous source. It has also been postulated that non-adjacent AlO.sub.2.sup.- and PO.sub.2.sup.+ tetrahedral pairs can be balanced by Na.sup.+ and OH.sup.-, respectively [Flanigen and Grose, Molecular Sieve Zeolites-I, ACS, Washington, D.C. (1971)].
In any event, all of the FAPO compositions of the present invention examined to date have exhibited cation-exchange capacity, in some cases to a significant degree, when analyzed using ion-exchange techniques heretofore employed with zeolitic aluminosilicates. All have uniform pore diameters which are inherent in the lattice structure of each species and which are at least about 3 .ANG. in diameter. Ion exchange is ordinarily possible only after the organic moiety present as a result of synthesis has been removed from the pore system. Dehydration to remove water present in the as-synthesized FAPO compositions can usually be accomplished, to some degree at least, in the usual manner without removal of the organic moiety, but the absence of the organic species greatly facilitates adsorption and desorption procedures. As illustrated hereinafter, the FAPO materials have various degrees of hydrothermal and thermal stability, some being quite remarkable in this regard, and function well as molecular sieve adsorbents and hydrocarbon conversion catalyst or catalyst bases.
The present invention relates to titanium-containing molecular sieves comprising a three-dimensional microporous crystal framework structure of [TiO.sub.2 ], [AlO.sub.2 ] and [PO.sub.2 ] tetrahedral units which has a unit empirical formula on an anhydrous basis of:
mR:(Ti.sub.x Al.sub.y P.sub.z)O.sub.2 (1)
wherein "R" represents at least one organic templating agent present in the intracrystalline pore system; "m" represents the moles of "R" present per mole of (Ti.sub.x Al.sub.y P.sub.z)O.sub.2 and has a value of between zero and about 5.0, the maximum value in each case depending upon the molecular dimensions of the templating agent and the available void volume of pore system of the particular titanium molecular sieve; "x", "y" and "z" represent the mole fractions of titanium, aluminum and phosphorus, respectively, present as tetrahedral oxides, representing the following values for "x", "y" and "z":
______________________________________Mole FractionPoint x y z______________________________________A 0.001 0.45 0.549B 0.88 0.01 0.11C 0.98 0.01 0.01D 0.29 0.70 0.01E 0.001 0.70 0.299______________________________________
The parameters "x", "y" and "z" are preferably within the following values for "x", "y" and "z":
______________________________________Mole FractionPoint x y z______________________________________a 0.002 0.499 0.499b 0.20 0.40 0.40c 0.20 0.50 0.30d 0.10 0.60 0.30e 0.002 0.60 0.398______________________________________
The molecular sieves of the present invention are generally employable as catalysts for various hydrocarbon conversion processes.
The molecular sieves employed in the instant process will be referred to hereinafter, solely for point of reference herein as "TAPO" molecular sieves, or as "TAPOs" if the reference is to the class as a whole. This designation is simply made for the sake of convenient reference herein and is not meant to designate a particular structure for any given TAPO molecular sieve. The members of the class of TAPO's employed hereinafter in the examples will be characterized simply by referring to such members as TAPO-5, TAPO-11, etc, i.e., a particular species will be referred to as TAPO-n where "n" is a number specific to a given class member as its preparation is reported herein. This designation is an arbitrary one and is not intended to denote structural relationship to another material(s) which may also be characterized by a numbering system.
The term "unit empirical formula" is used herein according to its common meaning to designate the simplest formula which gives the relative number of moles of titanium, aluminum and phosphorus which form the [TiO.sub.2 ], [PO.sub.2 ] and [AlO.sub.2 ] tetrahedral unit within a titanium-containing molecular sieve and which forms the molecular framework of the TAPO composition(s). The unit empirical formula is given in terms of titanium, aluminum and phosphorus as shown in Formula (1), above, and does not include other compounds, cations or anions which may be present as a result of the preparation or the existence of other impurities or materials in the bulk composition not containing the aforementioned tetrahedral unit. The amount of template R is reported as part of the composition when the as-synthesized unit empirical formula is given, and water may also be reported unless such is defined as the anhydrous form. For convenience, coefficient "m" for template "R" is reported as a value that is normalized by dividing the number of moles of organic by the total moles of titanium, aluminum and phosphorus.
The unit empirical formula for a TAPO may be given on an "as-synthesized" basis or may be given after an "as-synthesized" TAPO composition has been subjected to some post treatment process, e.g., calcination. The term "as-synthesized" herein shall be used to refer to the TAPO composition(s) formed as a result of the hydrothermal crystallization but before the TAPO composition has been subjected to post treatment to remove any volatile components present therein. The actual value of "m" for a post-treated TAPO will depend on several factors (including: the particular TAPO, template, severity of the post-treatment in terms of its ability to remove the template from the TAPO, the proposed application of the TAPO composition, and etc.) and the value for "m" can be within the range of values as defined for the as-synthesized TAPO compositions although such is generally less than the as-synthesized TAPO unless such post-treatment process adds template to the TAPO so treated. A TAPO composition which is in the calcined or other post-treatment form generally has an empirical formula represented by Formula (1), except that the value of "m" is generally less than about 0.02. Under sufficiently severe post-treatment conditions, e.g., roasting in air at high temperature for long periods (over 1 hr.), the value of "m" may be zero (0) or, in any event, the template, R, is undetectable by normal analytical procedures.
The molecular sieves of the present invention are generally further characterized by an intracrystalline adsorption capacity for water at 4.6 torr and about 24.degree. C. of about 3.0 weight percent. The adsorption of water has been observed to be completely reversible while retaining the same essential framework topology in both the hydrated and dehydrated state. The term "essential framework topology" is meant to designate the spatial arrangement of the primary bond linkages. A lack of change in the framework topology indicates that there is no disruption of these primary bond linkages.
The molecular sieves of the instant invention are generally synthesized by hydrothermal crystallization from a reaction mixture comprising reactive sources of titanium, aluminum and phosphorus, and one or more organic templating agents. Optionally, alkali metal(s) may be present in the reaction mixture. The reaction mixture is placed in a pressure vessel, preferably lined with an inert plastic material, such as polytetrafluoroethylene, and heated, preferably under the autogenous pressure, at a temperature of at least about 100.degree. C., and preferably between 100.degree. C. and 250.degree. C., until crystals of the molecular sieve product are obtained, usually for a period of from 2 hours to 2 weeks. While not essential to the synthesis of the instant molecular sieves, it has been found that in general stirring or other moderate agitation of the reaction mixture and/or seeding the reaction mixture with seed crystals of either the TAPO to be produced, or a topologically similar composition, facilitates the crystallization procedure. The product is recovered by any convenient method such as centrifugation or filtration.
After crystallization the TAPO may be isolated and washed with water and dried in air. As a result of the hydrothermal crystallization, the as-synthesized TAPO contains within its intracrystalline pore system at least one form of the template employed in its formation. Generally, the template is a molecular species, but it is possible, steric considerations permitting, that at least some of the template is present as a charge-balancing cation. Generally the template is too large to move freely through the intracrystalline pore system of the formed TAPO and may be removed by a post-treatment process, such as by calcining the TAPO at temperatures of between about 200.degree. C. and to about 700.degree. C. so as to thermally degrade the template or by employing some other post-treatment process for removal of at least part of the template from the TAPO. In some instances the pores of the TAPO are sufficiently large to permit transport of the template, and, accordingly, complete or partial removal thereof can be accomplished by conventional desorption procedures such as carried out in the case of zeolites.
The TAPOs are preferably formed from a reaction mixture having a mole fraction of alkali metal cation which is sufficiently low that it does not interfere with the formation of the TAPO composition. The TAPO compositions are generally formed from a reaction mixture containing reactive sources of TiO.sub.2, Al.sub.2 O.sub.3, and P.sub.2 O.sub.5 and an organic templating agent, said reaction mixture comprising a composition expressed in terms of molar oxide ratios of:
fR.sub.2 O:(Ti.sub.x Al.sub.y P.sub.z)O.sub.2 :gH.sub.2 O
wherein "R" is an organic templating agent; "f" has a value large enough to constitute an effective amount of "R" said effective amount being that amount which form said TAPO compositions; "g" has a value of from zero to 500; "x", "y" and "z" represent the mole fractions, respectively of titanium, aluminum and phosphorus in the (Ti.sub.x Al.sub.y P.sub.z)O.sub.2 constituent, and each has a value of at least 0.001 and being within the following values for "x", "y" and "z":
______________________________________Mole FractionPoint x y z______________________________________h 0.001 0.989 0.01i 0.001 0.01 0.989j 0.32 0.24 0.44k 0.98 0.01 0.01______________________________________
Although the TAPO compositions will form if higher concentrations of alkali metal cation are present, such reaction mixtures are not generally preferred. A reaction mixture, expressed in terms of molar oxide ratios, comprising the following bulk composition is preferred:
oR.sub.2 O:wM.sub.2 O:(Ti.sub.x Al.sub.y P.sub.z)O.sub.2 :nH.sub.2 O
wherein "R" is an organic template; "o" has a value great enough to constitute an effective concentration of "R" and is preferably within the range of from greater than zero (0) to about 5.0; "M" is an alkali metal cation; "w" has a value of from zero to 2.5; "n" has a value between about zero (0) and about 500; "x", "y" and "z" represent the mole fractions, respectively, of titanium, aluminum and phosphorus in (Ti.sub.x Al.sub.y P.sub.z)O.sub.2 "x", "y" and "z" represent the mole fractions, respectively of titanium, aluminum and phosphorus in the (Ti.sub.x Al.sub.y P.sub.z)O.sub.2 constituent, and each has a value of at least 0.001 and being within the following values for "x", "y" and "z":
______________________________________ Mole FractionPoint x y z______________________________________h 0.001 0.989 0.01i 0.001 0.01 0.989j 0.32 0.24 0.44k 0.98 0.01 0.01______________________________________
When the TAPOs are synthesized by this method the value of "m" in Formula (1) is generally above about 0.02.
Though the presence of alkali metal cations is not preferred, when they are present in the reaction mixture it is preferred to first admix at least a portion (e.g., at least about 10 weight percent) of each of the aluminum and phosphorus sources in the substantial absence (e.g., preferably less than about 20 percent of the total weight of the aluminum source and phosphorus source) of the titanium source. This procedure avoids adding the phosphorus source to a basic reaction mixture containing the titanium source and aluminum source, (as was done in most of the published attempts to substitute isomorphously "PO.sub.2 ] tetrahedra for [SiO.sub.2 ] tetrahedra in zeolitic structures). Although the reaction mechanism is by no means clear at this time, the function of the template may be to favor the incorporation of [PO.sub.2 ] and [AlO.sub.2 ] tetrahedra in the framework structures of the crystalline products with [TiO.sub.2 ] tetrahedra isomorphously replacing [PO.sub.2 ] tetrahedra.
The reaction mixture from which these TAPOs are formed contains one or more organic templating agents (templates) which can be most any of those heretofore proposed for use in the synthesis of aluminosilicates and aluminophosphates. The template preferably contains at least one element of Group VA of the Periodic Table, particularly nitrogen, phosphorus, arsenic and/or antimony, more preferably nitrogen or phosphorus and most preferably nitrogen and are of the formula R.sub.4 X.sup.+ wherein X is selected from the group consisting of nitrogen, phosphorus, arsenic and/or antimony and R may be hydrogen, alkyl, aryl, araalkyl, or alkylaryl group and is preferably aryl or alkyl containing between 1 and 8 carbon atoms, although more than eight carbon atoms may be present in "R" of group of the template. Nitrogen-containing templates are preferred, including amines and quaternary ammonium compounds, the latter being represented generally by the formula R'.sub.4 N.sup.+ wherein each R' is an alkyl, aryl, alkylaryl, or araalkyl group; wherein R' preferably contains from 1 to 8 carbon atoms or higher when R' is alkyl and greater than 6 carbon atoms when R' is otherwise, as hereinbefore discussed. Polymeric quaternary ammonium salts such as [(C.sub.14 H.sub.32 N.sub.2)(OH).sub.2 ].sub.x wherein "x" has a value of at least 2 may also be employed. The mono-, di- and triamines, including mixed amines, may also be employed as templates either alone or in combination with a quaternary ammonium compound or another template. The exact relationship of various templates when concurrently employed is not clearly understood. Mixtures of two or more templating agents can produce either mixtures of TAPOs or in the instance where one template is more strongly directing than another template the more strongly directing template may control the course of the hydrothermal crystallization wherein with the other template serving primarily to establish the pH conditions of the reaction mixture.
Representative templates include tetramethylammonium, tetraethylammonium, tetrapropylammonium or tetrabutylammonium ions; di-n-propylamine; tripropylamine; triethylamine; triethanolamine; piperidine; cyclohexylamine; 2-methylpyridine; N,N-dimethylbenzylamine; N,N-diethylethanolamine; dicyclohexylamine; N,N-dimethylethanolamine; 1,4-diazabicyclo (2,2,2) octane; N-methyldiethanolamine, N-methylethanolamine; N-methylcyclohexylamine; 3-methylpyridine; 4-methylpyridine; quinuclidine; N,N'-dimethyl-1,4-diazabicyclo (2,2,2) octane ion; di-n-butylamine, neopentylamine; di-n-pentylamine; isopropylamine; t-butylamine; ethylenediamine; pyrrolidine; and 2-imidazolidone. As will be readily apparent from the illustrative examples set forth hereinafter, not every template will produce every TAPO composition although a single template can, with proper selection of the reaction conditions, cause the formation of different TAPO compositions, and a given TAPO composition can be produced using different templates.
In those instances where an aluminum alkoxide is the reactive aluminum source, the corresponding alcohol is necessarily present in the reaction mixture since it is a hydrolysis product of the alkoxide. It has not as yet been determined whether this alcohol participates in the synthesis process as a templating agent, or in some other function and, accordingly, is not reported as a template in the unit formula of the TAPOs, although such may be acting as templates.
Alkali metal cations if present in the reaction mixture may facilitate the crystallization of certain TAPO phases, although the exact function of such cations, when present, in crystallization, if any, is not presently known. Alkali cations present in the reaction mixture generally appear in the formed TAPO composition, either as occluded (extraneous) cations and/or as structural cations balancing net negative charges at various sites in the crystal lattice. It should be understood that although the unit formula for the TAPOs does not specifically recite the presence of alkali cations they are not excluded in the same sense that hydrogen cations and/or hydroxyl groups are not specifically provided for in the traditional formulae for zeolitic aluminosilicates.
Most any reactive titanium source may be employed herein. The preferred reactive titanium sources include titanium alkoxides, water-soluble titanates and titanium chelates.
Most any reactive phosphorous source may be employed. Phosphoric acid is the most suitable phosphorus source employed to date. Accordingly, other acids of phosphorus are generally believed to be suitable phosphorus sources for use herein. Organic phosphates such as triethyl phosphate have been found satisfactory, and so also have crystalline or amorphous aluminophosphates such as the AlPO.sub.4 compositions of U.S. Pat. No. 4,310,440. Organo-phosphorus compounds, such as tetrabutyl-phosphonium bromide have not, apparently, served as reactive sources of phosphorus, but these compounds do function as templating agents and may also be capable of being suitable phosphorus sources under proper process conditions (yet to be ascertained). Organic phosphorus compounds, e.g., esters, are believed to be generally suitable since they can generate acids of phosphorus in situ. Conventional phosphorus salts, such as sodium metaphosphate, may be used, at least in part as the phosphorus source, but they are not preferred.
Most any reactive aluminum source may be employed herein. The preferred reactive aluminum sources include aluminum alkoxides, such as aluminum isopropoxide, and pseudoboehmite. Crystalline or amorphous aluminophosphates which are a suitable source of phosphorus are, of course, also suitable sources of aluminum. Other sources of aluminum used in zeolite synthesis, such as gibbsite, sodium aluminate and aluminum trichloride, can be employed but as generally not preferred.
Since the exact nature of the TAPO molecular sieves of the present invention are not clearly understood at present, although all are believed to contain [TiO.sub.2 ] tetrahedra in the three-dimensional microporous crystal framework structure, it is advantageous to characterize the TAPO molecular sieves by means of their chemical composition. This is due to the low level of titanium present in certain of the instant molecular sieves prepared to date which makes it difficult to ascertain the exact nature of the interaction between titanium, aluminum and phosphorus. As a result, although it is believed that titanium, [TiO.sub.2 ], has substituted isomorphously for [AlO.sub.2 ] or [PO.sub.2 ] tetrahedra, it is appropriate to characterize certain TAPO compositions by reference to their chemical composition in terms of the mole ratios of oxides in the as-synthesized and anhydrous form as:
vR:pTiO.sub.2 :qAl.sub.2 O.sub.3 :rP.sub.2 O.sub.5
wherein "R" represents at least one organic templating agent present in the intracrystalline pore system; "v" represents an effective amount of the organic templating agent to form said TAPO compositions and preferably has a value between and including zero and about 3.0; "p", "q" and "r" represent moles, respectively, of titanium, alumina and phosphorus pentaoxide, based on said moles being such that they are within the following values for "p", "q" and "r".
______________________________________ Mole FractionPoint p q r______________________________________A 0.004 1.0 1.22B 176 1.0 11.0C 196 1.0 1.0D 0.828 1.0 0.0143E 0.003 1.0 0.427______________________________________
The parameters "p", "q" and "r" are preferably within the following values for "p", "q" and "r":
______________________________________ Mole FractionPoint p q r______________________________________a 0.008 1.0 1.0b 1.0 1.0 1.0c 0.80 1.0 0.60d 0.333 1.0 0.50e 0.067 1.0 0.663______________________________________
The instant invention relates to a new class of crystalline molecular sieves in which at least two elements capable of forming three-dimensional microporous framework form crystal framework structures of AlO.sub.2.sup.-, PO.sub.2.sup.+ and MO.sub.2.sup.n tetrahedral oxide units wherein "MO.sub.2.sup.n " represents at least two different elements present as tetrahedral units "MO.sub.2.sup.n " with charge "n" where "n" may be -3, -2, -1, 0 or +1. These new molecular sieves exhibit ion-exchange, adsorption and catalytic properties and accordingly find wide use as adsorbents and catalysts. The members of this novel class of compositions have crystal framework structures of AlO.sub.2.sup.-, PO.sub.2.sup.+ and MO.sub.2.sup.n tetrahedral units and have an empirical chemical composition on an anhydrous basis expressed by the formula:
mR: (M.sub.x Al.sub.y P.sub.z)O.sub.2
wherein "R" represents at least one organic templating agent present in the intracrystalline pore system; "m" represents the molar amount of "R" present per mole of (M.sub.x Al.sub.y P.sub.z)O.sub.2 ; "M" represents at least two elements capable of forming framework tetrahedral oxides; and "x", "y" and "z" represent the mole fractions of "M", aluminum and phosphorus, respectively, present as tetrahedral oxides. "M" is at least two different elements (M.sub.1 and M.sub.2) such that the molecular sieves contain at least two framework tetrahedral units in addition to AlO.sub.2.sup.- and PO.sub.2.sup.+. "M" is at least one element selected from the group consisting of arsenic, beryllium, boron, chromium, gallium, germanium, lithium and vanadium and is at least one element selected from the group consisting of cobalt, iron, magnesium, manganese, titanium and zinc.
The molecular sieves of the instant invention will be generally referred to herein by the acronym or "ELAPO" to designate elements "M" in a framework of AlO.sub.2.sup.-, PO.sub.2.sup.+ and MO.sub.2.sup.n tetrahedral units. Actual class members will be identified by replacing the "EL" of the acronym with the elements present as MO.sub.2.sup.n tetrahedral units. For example, "MgBeAPO" designates a molecular sieve comprised of AlO.sub.2.sup.-, PO.sub.2.sup.+, MgO.sub.2.sup.-2 and BeO.sub.2.sup.-2 tetrahedral units. To identify various structural species which make up each of the subgeneric classes, each species is assigned a number and is identified as "ELAPO-i" wherein "i" is an integer. The given species designation is not intended to denote a similarity in structure to any other species denominated by a similar identification system.
The instant invention relates to a new class of molecular sieves in which at least two elements capable of forming framework tetrahedral oxides are provided to form crystal framework structures of AlO.sub.2.sup.-, PO.sub.2.sup.+ and MO.sub.2.sup.n tetrahedral wherein "M" represents at least two elements capable of forming tetrahedral units "M.sub.1 O.sub.2.sup.n " and "M.sub.2 O.sub.2.sup.n " where "M.sub.1 " and "M.sub.2 " are two different elements, where "n" is -3, -2, -1, 0 or +1 and where "M.sub.1 " is at least one element selected from the group consisting of arsenic, beryllium, boron, chromium, gallium, germanium, lithium and vanadium and "M.sub.2 " is at least one element selected from the group consisting of cobalt, iron, magnesium, manganese, titanium and zinc. These new molecular sieves exhibit ion-exchange, adsorption and catalytic properties and accordingly find wide use as adsorbents and catalysts.
The members of this novel class of compositions have crystalline three-dimensional microporous framework structures of AlO.sub.2.sup.-, PO.sub.2.sup.+ and MO.sub.2.sup.n tetrahedral units and have an empirical chemical composition on an anhydrous basis expressed by the formula:
mR: (M.sub.x Al.sub.y P.sub.z)O.sub.2 ;
wherein "R" represents at least one organic templating agent present in the intracrystalline pore system; "m" represents the molar amount of "R" present per mole of (M.sub.x Al.sub.y P.sub.z)O.sub.2 and has a value of zero to about 0.3; "M" represents at least two elements capable of forming framework tetrahedral oxides where "M" is at least one element selected from the group consisting of arsenic, beryllium, boron, chromium, gallium, germanium, lithium and vanadium; and at least one element selected from the group consisting of cobalt, iron, magnesium, manganese, titanium, and zinc.
The relative amounts of elements "M", aluminum and phosphorus are expressed by the empirical chemical formula (anhydrous):
mR: (M.sub.x Al.sub.y P.sub.z)O.sub.2
where "x", "y" and "z" represent the mole fractions of said "M", aluminum and phosphorus. The individual mole fractions of each "M" (M.sub.1, M.sub.2, M.sub.3, etc.) may be represented by "x.sub.1 ", "x.sub.2 ", "x.sub.3 ", etc. wherein "x.sub.1 ", "x.sub.2 ", and "x.sub.3 ", and etc. represent the individual mole fractions of elements M.sub.1, M.sub.2, M.sub.3, and etc. for "M" as above defined. The values of "x.sub.1 ", "x.sub.2 ", "x.sub.3 ", etc. are as defined for "x", hereinafter, where "x.sub.1 "+"x.sub.2 "+"x.sub.3 " . . . ="x" and where x.sub.1, x.sub.2, x.sub.3, etc. are each at least 0.01.
The molecular sieves of the instant invention have crystalline three-dimensional microporous framework structures of MO.sub.2.sup.n, AlO.sub.2.sup.- and PO.sub.2.sup.+ tetrahedral units having an empirical chemical composition on an anhydrous basis expressed by the formula:
mR: (M.sub.x Al.sub.y P.sub.z)O.sub.2
wherein "R" represents at least one organic templating agent present in the intracrystalline pore system; "m" represents a molar amount of "R" present per mole of (M.sub.x Al.sub.y P.sub.z)O.sub.2 and has a value of zero to about 0.3; "M" represents at least two different elements capable of forming framework tetrahedral oxides, as hereinbefore defined, and "x", "y" and "z" represent the mole fractions of "M", aluminum and phosphorus, respectively, present as tetrahedral oxides; said mole fractions "x", "y" and "z" being generally defined as within the following values for "x", "y", and "z":
______________________________________ Mole FractionPoint x y z______________________________________A 0.02 0.60 0.38B 0.02 0.38 0.60C 0.39 0.01 0.60D 0.98 0.01 0.01E 0.39 0.60 0.01______________________________________
In a preferred sub-class of the ELAPOs of this invention, the values of "x", "y" and "z" in the formula above are within the following values for "x", "y" and "z":
______________________________________ Mole FractionPoint x y z______________________________________a 0.02 0.60 0.38b 0.02 0.38 0.60c 0.39 0.01 0.60d 0.60 0.01 0.39e 0.60 0.39 0.01f 0.39 0.60 0.01______________________________________
The ELAPOs of this invention are useful as adsorbents, catalysts, ion-exchangers, and the like in much the same fashion as aluminosilicates have been employed heretofore, although their chemical and physical properties are not necessarily similar to those observed for aluminosilicates.
ELAPO compositions are generally synthesized by hydrothermal crystallization from a reaction mixture containing reactive sources of the elements "M", aluminum and phosphorus, preferably an organic templating, i.e., structure-directing, agent, preferably a compound of an element of Group VA of the Periodic Table, and/or optionally an alkali or other metal. The reaction mixture is generally placed in a sealed pressure vessel, preferably lined with an inert plastic material such as polytetrafluoroethylene and heated, preferably under autogenous pressure at a temperature between 50.degree. C. and 250.degree. C., and preferably between 100.degree. C. and 200.degree. C. until crystals of the ELAPO product are obtained, usually a period of from several hours to several weeks. Typical crystallization times are from about 2 hours to about 30 days with from about 2 hours to about 20 days being generally employed to obtain crystals of the ELAPSO products. The product is recovered by any convenient method such as centrifugation or filtration.
In synthesizing the ELAPO compositions of the instant invention, it is preferred to employ a reaction mixture composition expressed in terms of the molar ratios as follows:
aR:(M.sub.x Al.sub.y P.sub.z)O.sub.2 :bH.sub.2 O
wherein "R" is an organic templating agent; "a" is the amount of organic templating agent "R" and has a value of from zero to about 6 and is preferably an effective amount within the range of greater than zero (0) to about 6; "b" has a value of from zero (0) to about 500, preferably between about 2 and 300; "M" represents at least two elements, as above described, capable of forming tetrahedral oxide framework units, MO.sub.2.sup.n, with AlO.sub.2.sup.- and PO.sub.2.sup.+ tetrahedral units; "n" has a value of -3, -2, -1, 0 or +1; and "x", "y" and "z" represent the mole fractions of "M", aluminum and phosphorus, respectively, "y" and "z" each have a value of at least 0.01 and "x" has a value of at least 0.02 with each element "M" having a mole fraction of at least 0.01. The mole fractions "x", "y" and "z" are preferably within the following values for "x", "y" and "z":
______________________________________ Mole FractionPoint x y z______________________________________F 0.02 0.60 0.38G 0.02 0.38 0.60H 0.39 0.01 0.60I 0.98 0.01 0.01J 0.39 0.60 0.01______________________________________
In the foregoing expression of the reaction composition, the reactants are normalized with respect to a total of (M+Al+P)=(x+y+z)=1.00 mole, whereas in many of the working examples appearing hereinafter the reaction mixtures are expressed in terms of molar oxide ratios and may be normalized to 1.00 mole of P.sub.2 O.sub.5. This latter form is readily converted to the former form by routine calculations by dividing the total number of moles of "M", aluminum and phosphorus into the moles of each of "M", aluminum ad phosphorus. The moles of template and water are similarly normalized by dividing the total moles of "M", aluminum and phosphorus.
In forming the reaction mixture from which the instant molecular sieves are formed the organic templating agent can be any of those heretofore proposed for use in the synthesis of conventional zeolite aluminosilicates. In general these compounds contain elements of Group VA of the Periodic Table of Elements, particularly nitrogen, phosphorus, arsenic and antimony, preferably nitrogen or phosphorus and most preferably nitrogen, which compounds also contain at least one alkyl or aryl group having from 1 to 8 carbon atoms. Particularly preferred compounds for use as templating agents are the amines, quaternary phosphonium compounds and quaternary ammonium compounds, the latter two being represented generally by the formula R.sub.4 X.sup.+ wherein "X" is nitrogen or phosphorus and each R is an alkyl or aryl group containing from 1 to 8 carbon atoms. Polymeric quaternary ammonium salts such as [(C.sub.14 H.sub.32 N.sub.2) (OH).sub.2 ].sub.x wherein "x" has a value of at least 2 are also suitably employed. The mono-, di- and tri-amines are advantageously utilized, either alone or in combination with a quaternary ammonium compound or other templating compound. Mixtures of two or more templating agents can either produce mixtures of the desired ELAPOs or the more strongly directing templating species may control the course of the reaction with the other templating species serving primarily to establish the pH conditions of the reaction gel. Representative templating agents include tetramethylammonium, tetraethylammonium, tetrapropylammonium or tetrabutylammonium ions; tetrapentylammonium ion; di-n-propylamine; tripropylamine; triethylamine; triethanolamine; piperidine; cyclohexylamine; 2-methylpyridine; N,N-dimethylbenzylamine; N,N-dimethylethanolamine; choline; N,N'-dimethylpiperazine; 1,4-diazabicyclo (2,2,2,) octane; N-methyldiethanolamine, N-methylethanolamine; N-methylpiperidine; 3-methylpiperidine; N-methylcyclohexylamine; 3-methylpyridine; 4-methylpyridine; quinuclidine; N,N'-dimethyl-1,4-diazabicyclo (2,2,2) octane ion; di-n-butylamine, neopentylamine; di-n-pentylamine; isopropylamine; t-butylamine; ethylenediamine; pyrrolidine; and 2-imidazolidone. Not every templating agent will direct the formation of every species of ELAPO, i.e., a single templating agent can, with proper manipulation of the reaction conditions, direct the formation of several ELAPO compositions, and a given ELAPO composition can be produced using several different templating agents.
The most suitable phosphorus source yet found for the present process is phosphoric acid, but organic phosphates such as triethyl phosphate may be satisfactory, and so also may crystalline or amorphous aluminophosphates such as the AlPO.sub.4 composition of U.S. Pat. No. 4,310,440. Organo-phosphorus compounds, such as tetrabutylphosphonium bromide, do not apparently serve as reactive sources of phosphorus, but these compounds may function as templating agents. Conventional phosphorus salts such as sodium metaphosphate, may be used, at least in part, as the phosphorus source, but are not preferred.
The preferred aluminum source is either an aluminum alkoxide, such as aluminum isoproproxide, or pseudoboehmite. The crystalline or amorphous aluminophosphates which are a suitable source of phosphorus are, of course, also suitable sources of aluminum. Other sources of aluminum used in zeolite synthesis, such as gibbsite, sodium aluminate and aluminum trichloride, can be employed but are not preferred.
The elements "M" can be introduced into the reaction system in any form which permits the formation in situ of reactive form of the element, i.e., reactive to form the framework tetrahedral oxide unit of the element. The organic and inorganic salts, of "M" such as oxides, alkoxides, hydroxides, halides and carboxylates, may be employed including the chlorides, bromides, iodides, nitrates, sulfates, acetates, formates, ethoxides, propoxides and the like.
While not essential to the synthesis of ELAPO compositions, stirring or other moderate agitation of the reaction mixture and/or seeding the reaction mixture with seed crystals of either the ELAPO species to be produced or a topologically similar species, such as aluminophosphate, aluminosilicate or molecular sieve compositions, facilitates the crystallization procedure.
After crystallization the ELAPO product may be isolated and advantageously washed with water and dried in air. The as-synthesized ELAPO generally contains within its internal pore system at least one form of the templating agent employed in its formation. Most commonly the organic moiety is present, at least in part, as a charge-balancing cation as is generally the case with as-synthesized aluminosilicate zeolites prepared from organic-containing reaction systems. It is possible, however, that some or all of the organic moiety is an occluded molecular species in a particular ELAPO species. As a general rule the templating agent, and hence the occluded organic species, is too large to move freely through the pore system of the ELAPO product and must be removed by calcining the ELAPO at temperatures of 200.degree. C. to 700.degree. C. to thermally degrade the organic species. In a few instances the pores of the ELAPO product are sufficiently large to permit transport of the templating agent, particularly if the latter is a small molecule, and accordingly complete or partial removal thereof can be accomplished by conventional desorption procedures such as carried out in the case of zeolites. it will be understood that the term "as-synthesized" as used herein does not include the condition of the ELAPO phase wherein the organic moiety occupying the intracrystalline pore system as a result of the hydrothermal crystallization process has been reduced by post-synthesis treatment such that the value of "m" in the composition formula
mR: (M.sub.x Al.sub.y P.sub.z)O.sub.2
has a value of less than 0.02. The other symbols of the formula are as defined hereinabove. In those preparations in which an alkoxide is employed as the source of element "M", aluminum or phosphorus, the corresponding alcohol is necessarily present in the reaction mixture since it is a hydrolysis product of the alkoxide. It has not been determined whether this alcohol participates in the synthesis process as a templating agent. For the purposes of this application, however, this alcohol is arbitrarily omitted from the class of templating agents, even if it is present in the as-synthesized ELAPO material.
Since the present ELAPO compositions are formed from MO.sub.2.sup.n, AlO.sub.2, and PO.sub.2.sup.+ tetrahedral oxide units which, respectively, have a net charge of "n", (where "m" may be -3, -2, -1, 0 or +1), -1, the matter of cation exchangeability is considerably more complicated than in the case of zeolitic molecular sieves in which, ideally, there is a stoichlometric relationship between AlO.sub.2.sup.- tetrahedra and charge-balancing cations. In the instant compositions, an AlO.sub.2.sup.- tetrahedron can be balanced electrically either by association with a PO.sub.2.sup.+ tetrahedron or a simple cation such as an alkali metal cation, a proton (H.sup.+), a cation of "M" present in the reaction mixture, or an organic cation derived from the templating agent. Similarly an MO.sub.2.sup.n tetrahedron, where "n" is negative, can be balanced electrically by association with PO.sub.2.sup.+ tetrahedra, a cation of "M" present in the reaction mixture, organic cations derived from the templating agent, a simple cation such as an alkali metal cation, or other divalent or polyvalent metal cation, a proton (H.sup.+), anions or cations introduced from an extraneous source. It has also been postulated that non-adjacent AlO.sub.2 - and PO.sub.2.sup.+ tetrahedral pairs can be balanced by Na.sup.+ and OH.sup.- respectively [Flanigen and Grose, Molecular Sieve Zeolites-I, ACS, Washington, DC (1971)]
The ELAPO compositions of the present invention may exhibit cation-exchange capacity when analyzed using ion-exchange techniques heretofore employed with zeolitic aluminosilicates and have pore diameters which are inherent in the lattice structure of each species and which are at least about 3 .ANG. in diameter. Ion exchange of ELAPO compositions is ordinarily possible only after the organic moiety derived from the template, present as a result of synthesis, has been removed from the pore system. Dehydration to remove water present in the as-synthesized ELAPO compositions can usually be accomplished, to some degree at least, in the usual manner without removal of the organic moiety, but the absence of the organic species greatly facilitates adsorption and desorption procedures. The ELAPO materials have various degrees of hydrothermal and thermal stability, some being quite remarkable in this regard, and function well as molecular sieve adsorbents and hydrocarbon conversion catalysts or catalyst bases.
NZ-MS CATALYSTS
The specific NZ-MSs employed in the instant invention are characterized in their calcined form by an adsorption of oxygen of at least 4 percent by weight at a partial pressure of 100 torr and a temperature of -186.degree. C. Further, the NZ-MSs are preferably characterized in their calcined form by an adsorption of isobutane of at least 2 percent by weight at a partial pressure of 500 torr and a temperature of 20.degree. C. The non-zeolitic molecular sieves are more preferably characterized by one of the aforementioned adsorption criteria and also characterized by an adsorption of triethylamine of from zero to less than 5 percent by weight, preferably less than 3 weight percent, at a partial pressure of 500 torr and a temperature of 20.degree. C.
The NZ-MSs employed herein are characterized by the aforementioned adsorption criteria. Certain NZ-MS species which may be employed herein are designated in one or more of the aforementioned subclasses of the class of NZ-MS by a "-n" designation of -11, -14, -17, -18, -25, -31, -33, -34, -35, -39, -40, -44 and -47. NZ-MSs characterized by the above described adsorption of oxygen include, but are not limited to, ELAPSO-11, ELAPSO-14, ELAPSO-17, ELAPSO-18, ELAPSO-34, ELAPSO-40, ELAPSO-41, ELAPSO-44, ELAPSO-47, CoAPSO-11, CoAPSO-31, CoAPSO-34, CoAPSO-35, CoAPSO-39, CoAPSO-44, FeAPSO-11, FeAPSO-31, FeAPSO-34, FeAPSO-35, FeAPSO-44, MgAPSO-11, MgAPSO-31, MgAPSO-34, MgAPSO-35, MgAPSO-39, MgAPSO-44, MgAPSO-47, MnAPSO-11, MnAPSO-31, MnAPSO-34, MnAPSO-35, MnAPSO-44, MnAPSO-47, TiAPSO-11, TiAPSO-34, TiAPSO-35, TiAPSO-44, ZnAPSO-11, ZnAPSO-31, ZnAPSO-34, ZnAPSO-35, ZnAPSO-39, ZnAPSO-44, ZnAPSO-47, CoMgAPSO-11, CoMgAPSO-34, CoMnMgAPSO-11, MeAPO-11, MEAPO-14, MeAPO-17, MeAPO-34, MeAPO-35, MeAPO-39, MeAPO-44, MeAPO-47, TiAPO-11, TiAPO-18, TiAPO-31, FeAPO-11, FeAPO-17, FeAPO-18, FeAPO-34, FeAPO-35, ELAPO-11, ELAPO-31, ELAPO-34, ELAPO-35, ELAPO-40, ELAPO-41 ELAPO-44, ELAPO-47, SAPO-11, SAPO-17, SAPO-31, SAPO-34, SAPO-35, SAPO-40, SAPO-41, SAPO-44 and mixtures thereof.
The above characterization of the NZ-MSs employed in the instant invention relates to an adsorption characterization that is carried out on a NZ-MS which has been subjected to a post synthesis treatment, e.g., calcination or chemical treatment, to remove a substantial portion of the template "R" which is present as a result of synthesis. Although a particular NZ-MS is characterized herein by reference to its adsorption of isobutane or triethylamine as being to the adsorption characteristics of the NZ-MS in its calcined form, the instant invention necessarily includes the use of a non-calcined or modified NZ-MSs which are characterized by such adsorption in the modified or calcined form, since upon use of such a non-calcined NZ-MS in the instant process at effective hydrocracking conditions the NZ-MS may be calcined or hydrothermally treated in situ so as to have one or more of the characteristic adsorptions of oxygen, isobutane and triethylamine. Thus, the NZ-MS may be rendered in situ to a form characterized by the aforementioned adsorption characteristics and such is within the scope of the instant invention. For example, an as-synthesized MgAPO-11 or MgAPSO-11 are not characterized by the aforementioned adsorption of isobutane due to the presence of template "R" which is present as a result of synthesis, although the calcined form of MgAPO-11 and MgAPSO-11 are characterized by the aforementioned adsorption of isobutane. Thus, reference to a NZ-MS having a particular adsorption characteristic in its calcined form is not intended to exclude the use of the NZ-MS in its as-synthesized form which upon in-situ calcination, hydrothermal treatment and/or other treatment, e.g., ion exchange with suitable atoms, would have such adsorption characteristics.
As discussed above it has been found that this class of NZ-MS provides product distributions not observed by use of traditional hydrocracking catalysts containing zeolitic aluminosilicate components. Heretofore, the catalysts of the prior art (containing zeolite) have generally exhibited a decrease in gasoline yield and/or conversion for the optimization of a particular process variable or product characteristic e.g., octane of the gasoline product. Such penalties are reduced or eliminated by use of the instant catalysts. An increase in the isoparaffin to normal paraffins ratio is desirable in gasoline products and an increase is an indication of higher octane products.
In addition to the above improvement in the octane of the gasoline products, the improvement in octane permits the use of base metal catalysts in processes where noble metal catalysts were heretofore required to obtain high octane products. Since base metal catalysts are generally more resistant to feed contaminants, sulfur-containing organic compounds, the instant invention provides more resistant catalysts without the octane penalty heretofore associated with base metal catalysts. When noble metal catalysts are employed with the instant NZ-MS(s) the instant invention further provides an improvement in the isoparaffin content of the gasoline products.
The NZ-MSs of the instant invention may be employed in conjunction with traditional hydrocracking catalysts and accordingly, optionally, a zeolitic aluminosilicate component may be employed in conjunction with the NZ-MS containing catalysts. The zeolitic aluminosilicate component of such catalysts may be any aluminosilicate heretofore employed as a component in hydrocracking catalysts. Representative of the zeolitic aluminosilicates disclosed heretofore as employable as component parts of traditional hydrocracking catalysts are Zeolite Y (including steam stabilized and ultrastable Y), Zeolite X, Zeolite beta (U.S. Pat. No. 3,308,069), Zeolite KZ-20 (U.S. Pat. No. 3,445,727), Zeolite ZSM-3 (U.S. Pat. No. 3,415,736), faujasite, LZ-10 (U.K. Pat. No. 2,014,970, June 9, 1982), US-Y, ZSM-type zeolites, erionite, mordenite, offretite, chabazite, FU-1-type zeolite, NU-type zeolities and mixtures thereof. Traditional cracking catalysts containing amounts of Na.sub.2 O less than about one percent by weight are generally preferred.
Representative Y-type zeolites believed employable herein include, but are not limited to, those zeolite Y components, disclosed in U.S. Pat. Nos.: 3,130,007; 3,835,032; 3,830,725; 3,293,192; 3,449,070; 3,839,539; 3,867,310; 3,929,620; 3,929,621; 3,933,983; 4,058,484; 4,085,069; 4,175,059; 4,192,778; 3,676,368; 3,595,611; 3,594,331; 3,536,521; 3,293,192; 3,966,643; 3,966,882 and 3,957,623.
Another zeolitic aluminosilicate employable herein is "LZ-210", described in E.P.C. Publication No. 82,211 published June 29, 1983, incorporated herein. In one embodiment the silica-to-alumina mole ratio is between about 7 and about 11 and preferably between about 8 and about 10. Hydrocracking catalysts containing LZ-210 are disclosed in copending U.S. Ser. No. 490,951, filed May 2, 1983, incorporated herein by reference, and such may be employed herein as the optional traditional hydrocracking component.
The term "ZSM-type" zeolites is generally employed in the art to refer to those zeolites denominated by the nomenclature "ZSM-n" where "n" is an integer. The ZSM-type aluminosilicates include but are not limited to ZSM-5, ZSM-11, ZMS-12, ZSM-23, ZSM-35, ZSM-38, ZSM-48; and other similar materials.
ZSM-5 is described in greater detail in U.S. Pat. Nos. 3,702,886 and Re. 29,948. The entire descriptions contained within those patents, particularly the X-ray diffraction pattern of therein disclosed ZSM-5, are incorporated herein by reference.
ZSM-11 is described in U.S. Pat. No. 3,709,979. That description, and in particular the X-ray diffraction pattern of said ZSM-11, is incorporated herein by reference.
ZSM-12 is described in U.S. Pat. No. 3,832,449. That description, and in particular the X-ray diffraction pattern disclosed therein, is incorporated herein by reference.
ZSM-23 is described in U.S. Pat. No. 4,076,842. The entire content thereof, particularly the specification of the X-ray diffraction pattern of the disclosed zeolite, is incorporated herein by reference.
ZSM-35 is described in U.S. Pat. No. 4,016,245. The description of that zeolite, and particularly the X-ray diffraction pattern thereof, is incorporated herein by reference.
ZSM-38 is more particularly describing U.S. Pat. No. 4,046,859. The description of that zeolite, and particularly the specified X-ray diffraction pattern hereof, is incorporated herein by reference.
ZSM-48 is more particularly described in U.S. Pat. No. 4,423,021. The description of that zeolite, and particularly the specified X-ray diffraction pattern thereof, is incorporated herein by reference. In addition, crystalline silicates such as silicalite (U.S. Pat. No. 4,061,724) may be employed with the NZ-MSs of the instant invention.
FORMULATION OF NZ-MS HYDROCRACKING CATALYSTS
The catalysts of the instant invention comprise at least one NZ-MS, as above characterized, and, optionally, may also contain one or more traditional hydrocracking catalysts, including zeolitic aluminosilicate components and hydrogenation/cracking components such as nickel, and tungsten sulfide and the like. The relative amount of the NZ-MS component or traditional hydrocracking catalyst component, if any, will depend at least in part, on the selected crude oil feedstock and on the desired product distribution to be obtained therefrom, but in all instances an effective amount of at least one NZ-MS is employed. When a zeolitic aluminoslicate is employed as a part of the traditional hydrocracking component the relative weight ratio of the zeolitic aluminosilicate to the NZ-MS is generally between about 1:10 and about 500:1, desirably between about 1:10 and about 200:1, preferably between about 1:2 and about 50:1, and most preferably is between about 1:1 and about 20:1. The zeolitic aluminosilicate and NZ-MS may be ion-exchanged with a selected cation(s) and/or thermally treated either before or after mixture with each other or after such have been added separately or concurrently to one or more inorganic oxide matrix components. When the NZ-MS molecular sieves are ion exchanged such are preferably exchanged with a hydrogen-forming cation species, e.g., NH.sub.4.sup.+, H.sup.+, quaternary ammonium cations, etc. The NZ-MS preferably has at least part of its cations as hydrogen-forming cation species.
Any ion-exchange, impregnation and/or occlusion of the NZ-MS and/or zeolitic aluminosilicate(s), if any, may be carried out by contacting such with a solution of at least one cation, including those selected from the group of cations consisting of ammonium, Group IIA, Group IIIA, Group IIB to VIIB and rare earth cations selected from the group consisting of cerium, lanthanum, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium and mixtures thereof. The exact nature of the relationship of rare earth cations and the NZ-MSs and their effect on the activity and/or selectivity of the NZ-MS-containing catalyst is not clearly understood at present. The cation(s), e.g., rare earth cation, may replace at least a portion of the cations initially present in the zeolitic aluminosilicate and/or NZ-MS or may be present as impregnated or occluded species. Such cations may be present in an effective amount which may be between about 0.1 weight percent and about 20 weight percent, typically between about 0.5 and about 10 weight percent, based on the weight of the starting zeolitic aluminosilicate and/or NZ-MS.
The hydrocracking catalysts of this invention contain an effective amount of at least one hydrogenation component of the type commonly employed in hydrocracking catalysts. The hydrogenation catalyst (component) is generally selected from the group of hydrogenation catalysts consisting of one or more metals of Group VI B and Group VIII, including the salts, complexes and solutions containing such metals. The hydrogenation catalyst is preferably selected from the group of metals, salts and complexes of the group consisting of at least one of platinum, palladium, rhodium, iridium and mixtures thereof or the group consisting of at least one of nickel, molybdenum, cobalt, tungsten, titanium, chromium and mixtures thereof. As recognized in the art, the noble and base metals will not generally be employed in the same catalyst system although such are not excluded from the scope of this invention. Reference to the catalytically active metal or metals is intended to encompass such metal or metals in the elemental state or in some form such as an oxide, sulfide, halide, carboxylate and the like.
The hydrogenation component is present in an effective amount to provide the hydrogenation function of the hydrocracking catalyst. When the hydrogenation catalyst is a noble metal it is generally present in an amount between about 0.05% and about 1.5% by weight based on the total weight of the hydrocracking catalyst, including the weight of any binder or matrix material which may be present, as hereinafter discussed, although effective amounts outside this range may be employed. Although effective amounts in excess of 1.5 percent by weight may be employed, the preferred effective amount of the noble metal hydrogenation catalyst is between about 0.3% and about 1.2% by weight. When the hydrogenation catalyst is a base metal(s) the effective amount will generally be between about 1.0% and about 30% percent by weight or more of the base metal, expressed as the oxide(s), based on the total weight of the hydrocracking catalyst, although effective amounts outside this range may be employed.
The final form of the hydrogenation component of the hydrocracking catalyst is not narrowly limited herein but may be a metal oxide, metal sulfide or other catalytically active form. Since sulfur is typically present in the hydrocarbon feedstock being treated, the actual form of some of the hydrogenation component(s) may well in some cases be at least in part a sulfide due to in situ reactions. When a noble metal is employed as the hydrogenation component the catalyst is generally activated in air and then reduced in a hydrogen atmosphere. When a base metal is employed it is usually also treated with a sulfur compound.
The hydrogenation components can be incorporated into the overall catalyst composition by any one of numerous procedures. They can be added either to the NZ-MS component, zeolitic aluminosilicate component, if any, or to any metal oxide or to a combination thereof by ion exchange, impregnation, occlusion and the like. In the alternative, multiple hydrogenation components (two or more) may be added as powders in formulation of the catalyst. They may be added by co-mulling, impregnation, or ion exchange whereby one or more may be added to NZ-MS and/or zeolitic aluminosilicate. For example, noble or base metal compounds, such as the sulfides, oxides or water-soluble salts, can be added by co-mulling, impregnation or precipitation before the composite is finally calcined. In the alternative these components can be added to the finished particle by impregnation with an aqueous, alcoholic, hydrocarbon, or other nonaqueous solution of soluble compounds or precursors. Impregnation or co-mulling are generally the preferred techniques when the hydrogenation component is a base metal while ion-exchange techniques are generally preferred when noble metals are employed as the hydrogenation catalyst.
Although the hydrogenation components can be combined with the NZ-MS and/or zeolitic aluminosilicate, if any, as the oxides, that is generally not the case. They are usually added as a metal salt which can be thermally converted to the corresponding oxide in an oxidizing atmosphere or reduced to the metal with hydrogen or other reducing agent. The composition can be sulfided by reaction with a sulfur donor such as carbon disulfide, hydrogen sulfide, hydrocarbon thiols, elemental sulfur, and the like, described above. The above oxidizing or sulfiding processes are generally carried out on catalyst compositions which have been partially dried (as desired), tableted, pelleted, extruded (with binder or matrix), or formed by other means and then calcined, e.g., at a temperature above 600.degree. F., usually above 800.degree. F.
It is well known in the art that hydrocracking catalysts are generally employed with a binder material or, as commonly referred to, with an inorganic oxide matrix which can be inert or also catalytically active. For example inorganic matrices such as clay silica, alumina silica-alumina, silica-zirconia, silica-magnesia, alumin-boria, alumina-titania and the like and mixtures thereof may be employed. An inorganic oxide need not always be employed such as in the case of a preform containing the NZ-MS or may be employed in an amount between about 1% and about 95% by weight, preferably between about 10% and about 80% by weight, based on the total weight of the hydrocracking composition.
The term "crude oil feedstock" is used herein to denominate any crude oil feedstock or portion thereof and includes full range crude oils from primary, secondary or tertiary recovery from conventional or offshore oil fields and to the myriad of feedstocks derived therefrom. "Crude oil feedstocks" may also be "syncrudes" such as those that can be derived from coal, shale oil, tar sands and bitumens. The crude oil feedstock may be virgin (straight run) or generated synthetically by blending. Such crude oil feedstocks are traditionally desalted prior to use since sodium chloride is known to be a poison in many hydrocracking operations. Further, the term "crude oil feedstocks" is intended to include component parts of crude oils which have heretofore been generally employed as feedstocks or potential feeds and includes feeds such as distillate gas oils, heavy vacuum gas oils, VGO, atmospheric and vacuum resids, syncrudes, pulverized coal and fractions boiling above the traditional end of the gasoline boiling range which generally includes compounds containing greater than about eleven carbon atoms and combinations thereof. The feedstocks employed in hydrocracking generally have boiling points between about 400.degree. F. and about 900.degree. F.
In hydrocracking processes the hydrocarbon feedstock to be charged to the hydrocracking unit typically boils above 300.degree. F., preferably between about 400.degree. F. and 1200 .degree. F. and more preferably between about 400.degree. F. and about 900.degree. F. The hydrocarbon feed may be derived from many sources, as above discussed, including: catalytic cracking processes; coking processes; fractionators from crude oil; hydrocracking; pyrolysis processes; just to name a few. When operating a hydrocracking process to maximize gasoline production, the typical feedstock current in commercial use has an end boiling point not greater than about 800.degree. F. Typically, a light catalytic cycle oil, or a light virgin gas oil, or mixtures thereof, boiling in the range of from about 300.degree. F. to 800.degree. F. is employed as a feedstock. The feed may be pre-treated in a hydrotreater to effect hydrodenitrification and/or hydrodesulfurization. The feed may have a significant sulfur content, present as hydrogen sulfide, ranging from 0.1 to 3 weight percent, and the nitrogen content, present as ammonia, may be present in an amount up to 4000 parts per million or more. Temperature, space velocity, and other process variables may be adjusted to compensate for the effects of nitrogen on the hydrocracking catalyst activity. The feedstock is contacted in the hydrocracking reaction zone with the hydrocracking catalyst in the presence of hydrogen-containing gas and/or a hydrogen generating compound. Hydrogen is consumed in the hydrocracking process and an excess of hydrogen is typically maintained in the reaction zone. Advantageously, a hydrogen-to-oil (feed) ratio of at least 1,000 standard cubic feet of hydrogen per barrel of feed (SCFB) is employed, and the hydrogen-to-oil ratio may range up to 20,000 SCFB, preferably, about 4,000 to 12,000 SCFB is employed. The hydrocracking reaction zone is typically operated under conditions of elevated temperature and pressure. The total hydrocracking pressure is usually between about 400 and about 4,000 pounds per square inch gauge (psig) and, preferably, between about 500 and 2000 psig. The hydrocracking reaction is exothermic and a temperature rise occurs across the catalyst bed. Therefore, the inlet temperature to the hydrocracking reaction zone may be 10.degree. to 40.degree. F. lower than the exit temperature. The average hydrocracking catalyst bed temperature is between about 450.degree. F. and 800.degree. F. depending on the presence or absence of NH.sub.3 and the catalyst's age. The liquid hourly space velocity (LHSV) typically is between 0.2 and 5 volume of feed per hour per volume of catalyst, and preferably between 0.25 and 4 LHSV.
The following examples were carried out to demonstrate the use of the hydrocracking catalysts and hydrocracking processes of the instant invention and are not intended to be limiting thereof.
EXPERIMENTAL PROCEDURE
Hydrocracking catalysts were prepared as described in the following examples and tested for their utility as hydrocracking catalysts. The catalysts were employed as hydrocracking catalysts in a first stage hydrocracking process.
A selected catalyst was evaluated for hydrocracking by contacting the hydrocarbon feed (gas oil feed boiling between about 332.degree. F. and about 853.degree. F. (ASTM test method D-2887) and containing about 5000 ppm sulfur and 2000 ppm nitrogen) with the selected catalyst. The feedstock has a density of 0.8341 g/cc at 60.degree. F. The sulfur and nitrogen are present by adding 0.5 weight percent sulfur in the form of thiophene and 0.2 weight percent nitrogen in the form of t-butylamine to the feedstock, wherein the weight percents were based on the total weight of the feedstock. The hydrocracking process was carried out at a pressure of about 1450 psig and an temperature between about 685.degree. F. and about 709.degree. F. and at a LHSV (liquid hourly space velocity) of about 1.7. Hydrogen was introduced at a rate of about 8000 Standard Cubic Feet of hydrogen per barrel of feedstock.
The hydrocracking experiments were carried out by introducing a selected feedstock to a stainless steel reactor having an axial thermowell. The temperature in the reactor was monitored by thermocouple in the thermowell. The catalyst was in the form of extrudates and was placed in the reactor and mixed with quartz chips to minimize reactor hot spots.
The hydrocarbon feedstock employed in the following examples was a gas oil having an IBP (Initial Boiling Point) of 332.degree. F., a FBP (Final Boiling Point) of 853.degree. F. and an API Gravity of 37.9. The feedstock contained less than 0.1 weight percent total nitrogen. Chemical analysis of the feedstock gave:
______________________________________ VOLUME PERCENT______________________________________Total Aromatics 24.7Mono-aromatics 19.0Diaromatics 3.1Triaromatics 1.2Tetraaromatics 0.6Pentaaromatics 0.8Total Saturates 75.4______________________________________
EXAMPLES 1 to 3
A reference catalyst (Catalyst A) and two catalysts according to this invention (Catalyst B and Catalyst C) were prepared as follows. All weight are on an anhydrous basis unless otherwise designated.
Catalyst A was prepared using a zeolitic aluminoslilicate denominated LZ-210. The LZ-210 was prepared according to the disclosure of E.P.C. Publication No. 82,200 and had a SiO.sub.2 to Al.sub.2 O.sub.3 ratio of 9.0, was steamed at 600.degree. C. in 100% steam for 1 hour and was ammonium exchanged by refluxing for 1 hour 1 pound of LZ-210 per pound of NH.sub.4 NO.sub.3 (provided as a 10 percent by weight aqueous solution). Catalyst A was formed into a catalyst by mixing 140 grams of LZ-210 and 60 grams of a pseudoboehmite alumina (peptized with 4.2 milliliters of concentrated nitric acid in 60 ml. of water) and then mulling the mixture for 10 minutes. The mixture was formed into 1/16 inch extrudates, dried at 100.degree. C. for about 10 hours and calcined at 500.degree. C. in air for 2 hours. The calcination at 500.degree. C. was carried out in a stepwise manner by heating the catalyst to 220.degree. C. over a one hour period, heating the catalyst at 220.degree. C. for 1.5 hours, heating the catalyst from 220.degree. C. to 500.degree. C. over a one hour period and then heating the catalyst at 500.degree. C. for 2 hours. The calcined extrudates were pore filled with a Ni(NO.sub.3).sub.2.6H.sub.2 O and ammonium metatungstate solution by mixing and then drying the resulting mixture. The final Catalyst A was prepared to contain the following weight percent (wt.%) of oxides: 5% NiO, 20% WO.sub.3, 52.5% LZ-210 and 22.5% alumina. Chemical analysis of Catalyst A for NiO and WO.sub.3 gave 4.7 wt.% NiO and 20.8 wt.% WO.sub.3.
Catalyst B was prepared by employing SAPO-11 and LZ-210 in the formulation of a hydrocracking catalyst. SAPO-11 was prepared according to example 17 of U.S. Pat. No. 4,440,871 (except that the digestion time was 24 hours) and was employed in the as-synthesized form. The LZ-210 zeolite was the same steamed and ammonium-exchanged LZ-210 employed in Catalyst A. Catalyst B was prepared by mulling 15.0 grams of SAPO-11 and 105 grams of the LZ-210 zeolitic aluminosilicate employed in Catalyst A. A solution containing 42.4 grams of ammonium metatungstate and 33.93 grams of Ni(NO.sub.3).sub.2.6H.sub.2 O in 100 cubic centimeters (cc) of water was added to the mixture of SAPO-11 and LZ-210. Pseudobeohmite alumina (30.0 grams peptized by mixing with 4.2 milliliter of concentrated nitric acid in 60 milliliters in water) was added to the above mixture and the resulting mixture extruded to give 1/16 inch extrudates. The extrudates were dried and calcined at 500.degree. C. as described for Catalyst A. Catalyst B was prepared to contain the following weight percent oxides of: 5.0% NiO, 20% WO.sub.3, 52.5% LZ-210, 7.5% SAPO-11 and 15% Al.sub.2 O.sub.3. Chemical analysis of Catalyst B for NiO and WO.sub.3 gave 4 wt.% NiO and 16 wt.% WO.sub.3.
Catalyst C was prepared by employing SAPO-34 and LZ-210 to formulate the catalyst. SAPO-34 was prepared according to the procedure described in examples 32 to 38 of U.S. Pat. No. 4,440,871. The LZ-210 was the same LZ-210 employed in the preparation of Catalyst A. Catalyst C was prepared by mixing 25.08 grams of SAPO-34 and 175 grams of LZ-210. The mixture was mulled for fifteen minutes and 53.8 grams of the same peptized alumina employed in Catalyst B added. The resulting mixture was then mixed for fifteen minutes. Water was then added to this mixture to form an extrudable mixture and 1/16 inch extrudates formed. The calcined extrudates were pore filled by mixing a solution containing 19.39 grams of Ni(NO.sub.3).sub.2.6H.sub.2 O and 24.2 grams of ammonium tungstate in 53 cc of water. The extrudates were then dried and calcined at 500.degree. C. as described above for Catalyst A. Catalyst C was prepared to contain the following weight percent of oxides 5% NiO; 20% WO.sub.3, 52.5% LZ-210, 7.5% SAPO-34 and 15% alumina. Chemical analysis of Catalyst C for NiO and WO.sub.3 gave 4.99 wt.% NiO and 20.32 wt.% WO.sub.3.
EXAMPLES 4to 6
The catalysts prepared in examples 1 to 3 (Catalysts A, B and C) were evaluated as hydrocracking catalysts according to the above described procedure over a series of conversions as set forth below in Tables A, B and C. The products were analyzed and the light gasoline MON (Motor Octane Number) and RON (Research Octane Number) calculated using a volume average of C.sub.5 and C.sub.6 products using the octane values in ASTM report "Knocking Characterization of Pure Hydrocarbons", Technical Publication No. 225 (1958). The MON and RON were calculated using the compounds measured in the light gasoline fraction and include the following components: 2-methylbutane; n-pentane; 2,3-dimethylpentane; 2-methylpentane; 3-methylpentane; n-hexane; methylcyclopentane; 2,4-dimethylpentane; cyclohexane; and benzene. The "Conversion" is the weight percent of the feedstock converted to products boiling below 420.degree. F. The following products (as weight percent based on feedstock) are reported in Tables A, B and C: "C.sub.3 "=products containing three carbon atoms; "C.sub.1 to C.sub.4 "=the products containing one to four carbon atoms; "% C.sub.5 to 185.degree. F."=products containing at least 5 carbon atoms and boiling below 185.degree. F.; "C185 -420"=products boiling from 185.degree. F. to 420.degree. F., and "C.sub.5 to 420.degree. F.=products containing at least 5 carbon atoms and boiling under 420.degree. F. The C.sub.5, C.sub.6, C.sub.7, C.sub.8 and C.sub.9 products are reported below. The following products were measured in each case: "C.sub.5 "=n-pentane and 2-methylbutane; "C.sub.6 "=n-hexane, 2,3-dimethylbutane, 2-methylpentane and 3-methylpentane; "C.sub.7 "=n-heptane, 2-methylhexane, 3-methylhexane and 2,4-dimethylpentane; "C.sub.8 "=n-octane, 2,2,3-trimethylpentane, 2,4-dimethylhexane; 2,3-dimethylhexane, 2-methylheptane, 3,4-dimethylhexane and 3-methylheptane; "C.sub.9 "=n-nonane, 2,4-dimethylheptane, 2,6-dimethylheptane, 2,5-dimethylheptane, 4-methyloctane, 2-methyloctane and 3-methyloctane. The products are reported on a weight basis. The products are determined by the simulated distillation described in ASTM test method 2887.
Comparison of the product distribution obtained using Catalyst A and those obtained using Catalysts B and C demonstrate the improved octane number of the light gasoline fraction (C.sub.5 to 185.degree. F.) obtained using the catalyst of this invention when compared at similar conversion. Further, the C.sub.5 and C.sub.6 hydrocarbon iso/normal ratio increased for Catalysts B and C. Since iso-alkanes have higher octane numbers, the product obtained by use of Catalysts B and C have improved calculated octane numbers.
The data in Tables A, B and C are graphically depicted in FIGS. 1 to 13 and demonstrate the benefits obtained by use of the catalysts of the instant invention in hydrocracking processes. FIGS. 1 and 2 show a comparison between Catalysts A, B and C of the light gasoline yield (C.sub.5 -185.degree. F.) as a function of conversion. Catalysts B and C produced similar or higher yields of the light gasoline product as compared to that obtained by use of reference Catalyst A. FIGS. 3 and 4 compares the calculated RON (Research Octane Number) of the light gasoline fractions obtained by use of Catalyst A, B and C. Catalysts B and C produced light gasoline fractions having higher RON values as compared to the light gasoline fractions produced by use of Catalyst A. FIG. 5 compares the yield of the heavy gasoline fraction (C.sub.5 to 420.degree. F.) as a function of conversion for Catalyst A and C and shows that the reference catalyst produced more heavy gasoline product. FIG. 6 compares yield of the heavy gasoline fraction as a function of conversion for Catalysts A and Catalyst B. Surprisingly, the yield of the heavy gasoline fraction is similar to reference Catalyst A while the RON of the light gasoline fraction is improved with Catalyst B. FIGS. 7, 8, 9 and 10 compare the iso to normal ratios of the C.sub.5 and C.sub.6 hydrocarbons produced by use of Catalysts A, B and C. In each of these cases, Catalysts B and C produced products having a higher iso to normal ratio than the products produced by use of Catalyst A. FIG. 11 compares the iso to normal ratio of the C.sub.5, C.sub.6, C.sub.7, C.sub.8 and C.sub.9 hydrocarbons as a function of carbon number for Catalyst A and Catalyst B. The products obtained using Catalyst B showed a higher iso to normal ratio for C.sub.5, C.sub.6, C.sub.7, C.sub.8 and C.sub.9 hydrocarbons, thus indicating higher octane products. FIGS. 12 and 13 show the yield of C.sub.3 products as a function of conversion for Catalysts A, B and C. Catalyst C showed a slight increase in C.sub.3 products, as compared to Catalyst A, while Catalyst B was similar to Catalyst A in the yield of C.sub.3 products.
Thus, the above results demonstrate that the RON of the light gasoline fraction was improved by use of Catalyst B and Catalyst C and the iso to normal ratio of C.sub.5 to C.sub.9 products increased while the yield of the light gasoline and heavy gasoline fractions remained substantially unchanged or increased. Thus the octane number of the light gasoline fraction obtained using the SAPO-containing catalyst was increased relative to the same catalyst but without a SAPO component. The results also indicate that Catalyst B (containing SAPO-11) was superior to Catalyst C (containing SAPO-34) in its improvement of the octane number of the light gasoline products without a gasoline yield loss. SAPO-11 is characterized by the above discussed adsorption of isobutane while SAPO-34 is not and, accordingly, SAPO-11 is in the preferred class of NZ-MSs employed in this invention.
EXAMPLE 7
A catalyst was prepared employing SAPO-11 to demonstrate the hydrocracking and dewaxing functionality of the catalysts of this invention. SAPO-11 was prepared according to the procedure described in example 18 of U.S. Pat. No. 4,440,871, except the final molar ratio of di-n-propylamine to Al.sub.2 O.sub.3 was 1.0 to 1. The catalyst was prepared by mixing 150 grams of SAPO-11 with 100 grams of Kaiser medium density alumina and a sufficient amount of water to form an extrudate mixture (paste). The mixture was extruded into 1/16 inch extrudates and dried in air at 100.degree. C. for 16 hours. The extrudates were then calcined in air at 480.degree. C. for 2 hours. The extrudates (153 gram) were then mixed (pore filled) with 150 cc of an aqueous solution containing 40.0 grams of nickel nitrate hexahydrate and 48.8 grams of ammonium metatungstate. The mixture was then dried for 16 hours at 100.degree. C. and then calcined in air at 480.degree. C. for 2 hours. The catalyst was prepared to contain, given as the weight percent oxide: 5 wt.% NiO; 23 wt.% WO.sub.3 ; 36 wt.% SAPO-11; and 36% Al.sub.2 O.sub.3. Chemical analysis for NiO and WO.sub.3 gave 5.4 wt.% NiO and 23.0 wt.% WO.sub.3.
The catalyst was evaluated by contacting a selected feedstock with hydrogen at a total pressure of 2000 psig at a Liquid Hourly Space Velocity (LHSV) of one and a hydrogen flow rate of 10,000 SCFB (Standard Cubic Feed per Barrel) at temperatures between about 700.degree. F. and 840.degree. F. Products boiling below 600.degree. F. were collected and evaluated and the conversion given based on these products. The feedstock employed in this example was a vacuum gas oil having an IBP (Initial Boiling Point) of 560.degree. F. and a FBP (Final Boiling Point) of 1148.degree. F. (both determined by ASTM test method D-2887), API Gravity of 22.3 and having a pour point of greater than 95.degree. F. The feedstock was characterized by the following physical and chemical characteristics:
______________________________________ Weight Percent______________________________________Paraffins 24.1Mono-naphthenes 9.5Poly-naphthenes 8.7Mono-aromatics 13.3Di-aromatics 9.3Tri-aromatics 4.3Tetra-aromatics 2.7Penta-aromatics 0.7______________________________________
The reactor effluents were collected and the fraction of the feed (weight basis) converted to products boiling below 600.degree. F. determined by simulated distillation. The conversion is reported as the weight percent of feedstock converted to products boiling below 600.degree. F. The pour points were determined according to ASTM test method D-97-66 on the reactor effluent after maintaining the effluent at about 130.degree. F. during its collection.
The conversion and pour point were as follows:
______________________________________Temperature (.degree.F.) Conversion Pour Point (.degree.F.)______________________________________700 7.52 85724 9.84 80749 17.95 70769 30.06 55788 41.60 25797 36.64 35788 29.89 40788 33.74 45807 43.64 30821 45.12 30822 45.50 30840 56.88 20______________________________________
The above data demonstrate the conversion of the higher boiling feedstock to lower boiling products in the presence of hydrogen and that such products are characterized by a lower pour point than the initial feedstock.
TABLE A__________________________________________________________________________ (Catalyst A)__________________________________________________________________________ExperimentNo. Conv. C.sub.1 -C.sub.4 C.sub.3 C.sub.5 -185.degree. F. 185-420.degree. F. RON MON i/n-C.sub.5 n-C.sub.5 i-C.sub.5 i/n-C.sub.6 n-C.sub.6 i-C.sub.6 n-C.sub.7__________________________________________________________________________1 42.12 3.85 0.34 4.20 33.99 85.78 80.52 3.08 0.40 1.23 4.79 0.29 1.41 0.5672 41.47 3.91 0.34 4.15 33.28 85.91 80.64 3.12 0.40 1.23 4.88 0.29 1.40 0.5863 46.46 4.50 0.41 5.26 36.21 85.90 80.69 3.13 0.51 1.60 4.99 0.36 1.77 0.6874 46.40 4.40 0.41 5.38 36.09 85.82 80.46 3.13 0.51 1.61 5.00 0.37 1.84 0.5935 49.39 4.94 0.48 6.23 37.79 85.87 80.51 3.15 0.60 1.89 5.15 0.42 2.15 0.7416 49.50 5.07 0.50 6.41 37.68 85.85 80.42 3.20 0.60 1.93 5.15 0.43 2.23 0.608__________________________________________________________________________ Experiment Hours on No. i-C.sub.7 i/n-C.sub.7 n-C.sub.8 i-C.sub.8 i/n-C.sub.8 n-C.sub.9 i-C.sub. 9 i/n-C.sub.9 Stream (.degree.F.)__________________________________________________________________________ 1 3.70 6.53 0.428 4.29 10.02 0.424 3.80 8.97 68 686 2 3.91 6.66 0.415 4.59 11.06 0.431 3.98 9.23 93 687 3 4.75 6.91 0.485 6.34 13.06 0.446 4.29 9.63 118 692 4 4.05 6.83 0.454 5.60 12.33 0.428 4.03 9.42 141 961 5 5.26 7.10 0.540 6.91 12.79 0.482 4.84 10.03 164 695 6 4.31 7.09 0.471 5.89 12.50 0.455 4.27 9.37 188 695__________________________________________________________________________
TABLE B__________________________________________________________________________(Catalyst B)__________________________________________________________________________ExperimentNo. Conv. C.sub.1 -C.sub.4 C.sub.3 C.sub.5 -185.degree. F. 185-420.degree. F. RON MON i/n-C.sub.5 n-C.sub.5 i-C.sub.5 i/n-C.sub.6 n-C.sub.6 i-C.sub.6 n-C.sub.7__________________________________________________________________________1 38.82 3.69 0.31 3.79 31.03 86.58 80.91 3.38 0.34 1.15 5.68 0.23 1.31 0.4172 39.38 3.90 0.33 3.76 31.55 86.61 80.98 3.37 0.34 1.13 5.75 0.23 1.30 0.4513 43.55 3.32 0.39 4.89 33.82 87.10 81.09 3.67 0.41 1.52 6.51 0.27 1.74 0.4204 48.47 4.70 0.48 5.55 37.79 87.01 81.09 3.68 0.48 1.75 6.46 0.31 1.97 0.4845 66.99 7.18 0.73 10.41 48.32 87.33 81.21 4.04 0.85 3.42 7.10 0.53 3.80 0.5616 67.84 7.14 0.81 9.73 49.98 87.39 81.19 4.08 0.78 3.19 7.27 0.49 3.57 0.553__________________________________________________________________________ Experiment Hours on No. i-C.sub.7 i/n-C.sub.7 n-C.sub.8 i-C.sub.8 i/n-C.sub.8 n-C.sub.9 i-C.sub.9 i/n-C.sub.9 Stream (.degree.F.)__________________________________________________________________________ 1 3.41 8.18 0.295 4.76 16.14 0.335 3.54 10.58 68 686 2 3.73 8.27 0.327 5.20 15.90 0.357 3.84 10.75 92 685 3 4.01 9.55 0.297 5.04 16.98 0.327 3.85 11.78 140 692 4 4.52 9.34 0.362 5.93 16.38 0.358 4.13 11.55 165 696 5 5.61 10.0 0.387 6.89 17.80 0.388 4.62 11.90 212 708 6 5.71 10.3 0.399 6.93 17.35 0.388 4.66 12.00 236 707__________________________________________________________________________
TABLE C__________________________________________________________________________(CATALYST C)Experi- Hoursment onNo. Conv. C.sub.1 -C.sub.4 C.sub.3 C.sub.5 -185.degree. F. 185-420.degree. F. RON MON i/n-C.sub.5 n-C.sub.5 i-C.sub.5 i/n-C.sub.6 n-C.sub.6 i-C.sub.6 Stream (.degree.F.)__________________________________________________________________________1 37.89 0.35 3.72 3.37 30.73 86.94 81.07 3.44 0.29 1.01 5.97 0.19 1.16 64 6862 38.18 0.32 3.62 3.53 30.58 86.96 81.22 3.48 0.32 1.10 6.14 0.20 1.22 86 6863 41.18 0.38 3.71 4.29 31.98 87.09 81.06 3.52 0.37 1.35 6.69 0.23 1.54 110 6904 48.30 0.46 4.19 4.91 30.64 87.23 81.19 3.75 0.42 1.59 7.06 0.25 1.78 138 6955 43.70 0.46 4.53 5.45 33.12 87.13 81.10 3.72 0.47 1.74 6.85 0.29 1.97 160 6956 49.41 0.60 5.25 6.56 36.69 87.40 81.22 3.93 0.54 2.13 7.24 0.33 2.39 184 7037 49.80 0.59 5.39 7.00 36.68 87.42 81.11 4.00 0.56 2.24 7.36 0.35 2.58 208 7038 50.41 0.81 5.58 7.43 36.24 87.13 80.12 4.03 0.53 2.15 7.38 0.39 2.89 231 709__________________________________________________________________________

Number	Name	Date
3236762	Rabo	Feb 1966
3755145	Orkin	Aug 1973
3758402	Oleck et al.	Sep 1973
4239654	Gladrow et al.	Dec 1980
4327236	Klotz	Apr 1982
4340465	Miller et al.	Jul 1982
4428862	Ward et al.	Jan 1984
4434047	Hensley, Jr. et al.	Feb 1984
4440871	Lok et al.	Apr 1984
4499327	Kaiser	Feb 1985
4512875	Long et al.	Apr 1985
4513090	Eberly, Jr. et al.	Apr 1985
4567029	Wilson et al.	Jan 1986
4588846	Mitsui et al.	May 1986
4605790	Wojtkowski	Aug 1986
4683050	Ward	Jul 1987

Hydrocracking catalysts and processes employing non-zeolitic molecular sieves

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