Arsenic-aluminum-phosphorus-silicon-oxide molecular sieve compositions

FIELD OF THE INVENTION
The instant invention relates to a novel class of crystalline microporous molecular sieves, to the method of their preparation and to their use as adsorbents and catalysts. The invention relates to novel arsenic-aluminum-phosphorus-silicon-oxide molecular sieves containing framework tetrahedral oxide units of arsenic, aluminum, phosphorus and silicon. These compositions may be prepared hydrothermally from gels containing reactive compounds of arsenic, aluminum and phosphorus and silicon capable of forming framework tetrahedral oxides, and preferably at least one organic templating agent which function in part to determine the course of the crystallization mechanism and the structure of the crystalline product.
BACKGROUND OF THE INVENTION
Molecular sieves of the crystalline aluminosilicate zeolite type are well known in the art and now comprise over 150 species of both naturally occurring and synthetic compositions. In general the crystalline zeolites are formed from corner-sharing AlO.sub.2 and SiO.sub.2 tetrahedra and are characterized by having pore openings of uniform dimensions, having a significant ion-exchange capacity and being capable of reversibly desorbing an adsorbed phase which is dispersed throughout the internal voids of the crystal without displacing any atoms which make up the permanent crystal structure. Other crystalline microporous compositions which are not zeolitic, i.e. do not contain AlO.sub.2 tetrahedra as essential framework constituents, but which exhibit the ion-exchange and/or adsorption characteristics of the zeolites are also known. Metal organosilicates which are said to possess ion-exchange properties, have uniform pores and are capable of reversibly adsorbing molecules having molecular diameters of about 6.ANG. or less, are reported in U.S. Pat. No. 3,941,871 issued Mar. 2, 1976 to Dwyer et al. A pure silica polymorph, silicalite, having molecular sieving properties and a neutral framework containing neither cations nor cation sites is disclosed in U.S. Pat. No. 4,061,724 issued Dec. 6, 1977 to R. W. Grose et al.
A recently reported class of microporous compositions and the first framework oxide molecular sieves synthesized without silica, are the crystalline aluminophosphate compositions disclosed in U.S. Pat. No. 4,310,440 issued Jan. 12, 1982 to Wilson et al. These materials are formed from AlO.sub.2 and PO.sub.2 tetrahedra and have electrovalently neutral frameworks as in the case of silica polymorphs. Unlike the silica molecular sieve, silicalite, which is hydrophobic due to the absence of extra-structural cations, the aluminophosphate molecular sieves are moderately hydrophilic, apparently due to the difference in electronegativity between aluminum and phosphorus. Their intracrystalline pore volumes and pore diameters are comparable to those known for zeolites and silica molecular sieves.
In U.S. Pat. No. 4,440,871, there is described a novel class of silicon-substituted aluminophosphates which are both microporous and crystalline. The materials have a three dimensional crystal framework of PO.sub.2.sup.+, AlO.sub.2.sup.- and SiO.sub.2 tetrahedral units and, exclusive of any alkali metal or calcium which may optionally be present, an as-synthesized empirical chemical composition on an anhydrous basis of:
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, 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 silicoaluminophosphate species involved; and "x", "y", and "z" represent the mole fractions of silicon, aluminum and phosphorus, respectively, present as tetrahedral oxides. The minimum value for each of "x", "y", and "z" is 0.01 and preferably 0.02. The maximum value for "x" is 0.98; for "y" is 0.60; and for "z" is 0.52. These silicoaluminophosphates exhibit several physical and chemical properties which are characteristic of aluminosilicate zeolites and aluminophosphates.
In U.S. Pat. No. 4,500,651, there is described a novel class of titanium-containing molecular sieves whose chemical composition in the as-synthesized and anhydrous form is represented by the unit empirical formula:
mR:(Ti.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 (Ti.sub.x Al.sub.y P.sub.z)O.sub.2 and has a value of between zero and about 5.0; and "x", "y" and "z" represent the mole fractions of titanium, aluminum and phosphorus, respectively, present as tetrahedral oxides.
In U.S. Pat. No. 4,567,029, there is described a novel class of crystalline metal aluminophosphates having three-dimensional microporous framework structures of MO.sub.2, AlO.sub.2 and PO.sub.2 tetrahedral units and 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 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; "M" represents at least one metal of the group magnesium, manganese, zinc and cobalt; "x", "y", and "z" represent the mole fractions of the metal "M", aluminum and phosphorus, respectively, present as tetrahedral oxides.
In U.S. Pat. No. 4,544,143, there is described a novel class of crystalline ferroaluminophosphates having a three-dimensional microporous framework structure of FeO.sub.2, AlO.sub.2 and PO.sub.2 tetrahedral units and having an empirical chemical composition on an anhydrous basis expressed by the formula
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; and "x", "y" and "z" represent the mole fraction of the iron, aluminum and phosphorus, respectively, present as tetrahedral oxides.
The instant invention relates to new molecular sieve compositions comprising framework tetrahedral units of AsO.sub.2.sup.n, AlO.sub.2.sup.-, PO.sub.2.sup.+ and SiO.sub.2 where "n" is -1 or +1.

DESCRIPTION OF THE FIGURES
FIG. 1 is a ternary diagram wherein parameters relating to the instant compositions are set forth as mole fractions.
FIG. 2 is a ternary diagram wherein parameters relating to preferred compositions are set forth as mole fractions.
FIG. 3 is a ternary diagram wherein parameters relating to the reaction mixtures employed in the preparation of the compositions of this invention are set forth as mole fractions.

SUMMARY OF THE INVENTION
The instant invention relates to a new class of arsenic-aluminum-phosphorus-silicon-oxide molecular sieves having a crystal framework structure of AsO.sub.2.sup.n, AlO.sub.2, PO+and SiO.sub.2 tetrahedral oxide units where "n" is -1 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 As.sub.2.sup.n, 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:(As.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 (As.sub.w Al.sub.x P.sub.y.sub.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 arsenic, aluminum, phosphorus and silicon, respectively, present as tetrahedral oxides. These molecular sieve compositions comprise crystalline molecular sieves having a three-dimensional microporous framework structure of AsO.sub.2.sup.n, AlO.sub.2.sup.-, PO.sub.2.sup.+ and SiO.sub.2 tetrahedral units. The instant molecular sieve compositions are characterized in several ways as distinct from heretofore known molecular sieves, including the aforementioned ternary compositions.
The instant molecular sieves are characterized by the enhanced thermal stability of certain species and by the existence of species heretofore unknown for binary and ternary molecular sieves.
The molecular sieves of the instant invention will be generally referred to by the acronym "AsAPSO" to designate the framework of AsO.sub.2.sup.n, AlO.sub.2.sup.-, PO.sub.2.sup.+ and SiO.sub.2 tetrahedral oxide units where "n" has a value of -1 or +1. Actual class members will be identified by denominating the various structural species which make up the AsAPSO class by assigning a number and, accordingly, are identified as "AsAPSO-i" wherein "i" is an integer. 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.
DETAILED DESCRIPTION OF THE INVENTION
The instant invention relates to a new class of arsenic-aluminum-phosphorus-silicon-oxide molecular sieves comprising a crystal framework structure of AsO.sub.2.sup.n, AlO.sub.2.sup.-, PO.sub.2.sup.+ and SiO.sub.2 tetrahedral oxide units, where "n" has a value of -1 or +1. These new molecular sieves exhibit ion-exchange, adsorption and catalytic properties and, accordingly, find wide use as adsorbents and catalysts.
The AsAPSO molecular sieves of the instant invention comprise a framework structure of AsO.sub.2.sup.n, AlO.sub.2.sup.-, PO.sub.2.sup.+ and SiO.sub.2 tetrahedral oxides units (where "n" is -1 or +1) having an empirical chemical composition on an anhydrous basis expressed by the formula:
mR:(As.sub.w Sl.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 (As.sub.w Al.sub.x P.sub.y Si.sub.z)O.sub.2 and has a value of zero to about 0.3, but is preferably not greater than about 0.15; and "w", "x", "y" and "z" represent the mole fractions of arsenic, aluminum, phosphorus and silicon, respectively, present as tetrahedral oxides The mole fractions "w", "x", "y" and "z" are generally defined as being within the pentagonal compositional area defined by points A, B, C, D and E of the ternary diagram of FIG. 1. Points A, B, C, D and E of FIG. 1 have the following values for "w", "x", "y", and "z":
______________________________________ 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 AsAPSO molecular sieves the values of "w", "x", "y" and "z" in the above formula are within the hexagonal compositional area defined by the points a, b, c, d, e and f of the ternary diagram which is FIG. 2 of the drawings, said points a, b, c, d, e and f representing the following values for "w", "x", "y" and "z":
______________________________________ 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 0.39 0.60e 0.39 0.01 0.60f 0.60 0.01 0.39______________________________________
In an especially preferred subclass of the AsAPS0 molecular sieves the values of "w", "x", "y" and "z" in the formula are within the hexagonal compositional area defined by the points g, h, i, j, k and l of the ternary diagram which is FIG. 2 of the drawings, said points g, h, i, j, k and 1 representing the following values for "x", "y" and "z":
______________________________________ Mole FractionPoint x y z + w______________________________________g 0.50 0.40 0.10h 0.42 0.48 0.10i 0.38 0.48 0.14j 0.38 0.37 0.25k 0.45 0.30 0.25l 0.50 0.30 0.20______________________________________
The AsAPSOs 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.
AsAPSO compositions are generally synthesized by hydrothermal crystallization from a reaction mixture containing reactive sources of arsenic, aluminum, phosphorus and silicon, 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 AsAPSO product are obtained, usually for a period of from several hours to several weeks. Crystallization times of from about 2 hours to about 30 days are generally employed with from about 12 hours to about 10 days being typically employed. The product is recovered by any convenient method such as centrifugation or filtration.
In synthesizing the AsAPSO compositions of the instant invention, it is preferred to employ a reaction mixture composition expressed in terms of the molar ratios as follows:
aR:(As.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, and most preferably not more than about 1.0: "b" has a value of from zero (0) to about 500, preferably between about 2 and about 300, most preferably not greater than about 60; and "w", "x", "y" and "z" represent the mole fractions of arsenic, 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 pentagonal compositional area defined by points F, G, H, I and J of the ternary diagram of FIG. 3. Points F, G, H, I and J of FIG. 3 have the following values for "w", "x", "y" and "z":
______________________________________ 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______________________________________
Especially preferred reaction mixtures are those containing from about 1 to about 2 total moles of aluminum, and from about 1 to 2 moles of silicon and arsenic, per mole of phosphorus.
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, whereas in the examples the reaction mixtures are expressed in terms of molar oxide ratios normalized to the moles of P.sub.2 O.sub.5. This latter form is readily converted to the former form by routine calculations by dividing the number of moles of each component (including the template and water) by the total number of moles of arsenic, aluminum, phosphorus and silicon which results in normalized mole fractions based on total moles of the aforementioned components.
In forming reaction mixtures 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 and quaternary ammonium compounds, the latter two being represented generally by the formula R.sub.4 X.sup.+ wherein "X" is phosphorus or nitrogen 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 r more templating agents can either produce mixtures of the desired AsAPSOs 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; and tetrabutylammonium ions; tetrapentylammonium 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 AsAPSO, i.e., a single templating agent can, with proper manipulation of the reaction conditions, direct the formation of several AsAPSO compositions, and a given AsAFSO composition can be produced using several different templating agents.
The reactive phosphorus source is preferably phosphoric acid, but organic phosphates such as triethyl phosphate 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. Organophosphorus 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.
Most any reactive silicon source may be employed such that SiO.sub.2 tetrahedral units are formed in situ. The reactive silicon source may be silica in the form of a silica sol, may be a fumed silica or may be other conventional sources of silica used in zeolite synthesis such as reactive solid amorphous precipitated silicas, silica gel, alkoxides of silicon, silicic acid, alkali metal silicates, tetraelkyl orthosilicates (for example, tetraethyl orthosilicate), and the like.
The preferred aluminum source is either an aluminum alkoxide, such as aluminum isoproproxide, or pseudoboehmite. Aluminum chlorhydrol (Al.sub.2 Cl(OH).sub.5.2H.sub.2 O) may also be employed. 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 reactive source of arsenic can be introduced into the reaction system in any form which permits the formation in situ of a reactive form of arsenic, i.e., reactive to form the framework tetrahedral oxide unit of arsenic. Compounds of arsenic which may be employed include oxides, alkoxides, acetates, hydroxides, chlorides, bromides, iodides, sulfates, nitrates, carboxylates and the like.
While not essential to the synthesis of AsAPSO compositions, stirring or other moderate agitation of the reaction mixture and/or seeding the reaction mixture with seed crystals of either the AsAPSO species to be produced or a topologically similar aluminophosphate, aluminosilicate or molecular sieve composition, facilitates the crystallization procedure.
After crystallization the AsAPSO product may be isolated and advantageously washed with water and dried in air. The as-synthesized AsAPSO generally contains within its internal pore system at least one form of the templating agent employed in its formation. Most commonly the organic moiety derived from an organic template 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 AsAPSO 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 AsAPSO product and must be removed by calcining the AsAPSO at temperatures of 200.degree. C. to 700.degree. C. to thermally degrade the organic species. In a few instances the pores of the AsAPSO 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 are 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 AsAPSO phase wherein the organic moiety occupying the intracrystalline pore system as a result of the hydrothermal crystalline process has been reduced by post-synthesis treatment such that the value of "m" in the composition formula:
mR:(As.sub.w Al.sub.x P.sub.y Si.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 arsenic, aluminum, phosphorous and/or silicon, 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 AsAPSO material.
Since the present AsAPSO compositions are formed from AsO.sub.2, AlO.sub.2, PO.sub.2 and SiO.sub.2 tetrahedral units which, respectively, have a net charge of "n" (+1 or -1), -1, +1 and 0, 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.sup.- tetrahedra and charge-balancing cations. In the instant compositions, an AlOhd 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 arsenic or aluminum present in the reaction mixture, a proton (H+), or an organic cations derived from the templating agent. Similarly, a AsO.sub.2.sup.- tetrahedron can be balanced electrically by association with PO.sub.2.sup.+ tetrahedra, a cation of arsenic present in the reaction mixture, a simple cation such as an alkali metal cation, an organic cation drived from the templating agent, a proton (H+ ), or other divalent or polyvalent metal anions 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, DC (1971)].
The AsAPSO 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 AsAPSO compositions 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 AsAPSO 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 AsAPSO materials will have various degrees of hydrothermal and thermal stability, some being quite remarkable in this regard, and will function as molecular sieve adsorbents and hydrocarbon conversion catalysts or catalyst bases.
In preparing the AsAPSO composition it is preferred to use a stainless steel reaction vessel lined with an inert plastic material, e.g., polytetrafluoroethylene, to avoid contamination of the reaction mixture. In general, the final reaction mixture from which each AsAPSO composition is crystallized is prepared by forming mixtures of less than all of the reagents and thereafter incorporating into these mixtures additional reagents either singly or in the form of other intermediate mixtures of two or more reagents. In some instances the reagents admixed retain their identity in the intermediate mixture and in other cases some or all of the reagents are involved in chemical reactions to produce new reagents. The term "mixture" is applied in both cases. Further, it is preferred that the intermediate mixtures as well as the final reaction mixtures be stirred until substantially homogeneous.
X-ray patterns of reaction products are obtained by X-ray analysis, using standard X-ray powder diffraction techniques. The radiation source is a high-intensity, copper target, X-ray tube operated at 50 Kv and 40 ma. The diffraction pattern from the copper K-alpha radiation and graphite monochromator is suitably recorded by an X-ray spectrometer scintillation counter, pulse height analyzer and strip chart recorder. Flat compressed powder samples are scanned at 2.degree. (2 theta) per minute, using a two second time constant. Interplanar spacings (d) in Angstrom units are obtained from the position of the diffraction peaks expressed as 2.theta. where .theta. is the Bragg angle as observed on the strip chart. Intensities were determined from the heights of diffraction peaks after subtracting background, "I.sub.o " being the intensity of the strongest line or peak, and "I" being the intensity of each of the other peaks. Alternatively, the X-ray patterns may be obtained by use of computer based techniques using copper K-alpha radiation, Siemens type K-805 X-ray sources and Siemens D-500 X-ray powder diffractometers available from Siemens Corporation, Cherry Hill, N.J.
As will be understood by those skilled in the art, the determination of the parameter 2 theta is subject to both human and mechanical error, which in combination, can impose an uncertainty of about .+-.0.4.degree. on each reported value of 2 theta. This uncertainty is, of course, also manifested in the reported values of the d-spacings, which are calculated from the 2 theta values. This imprecision is general throughout the art and is not sufficient to preclude the differentiation of the present crystalline materials from each other and from the compositions of the prior art. In some of the X-ray patterns reported, the relative intensities of the d-spacings are indicated by the notations vs, s, m, w and vw which represent very strong, strong, medium, weak and very weak, respectively.
In certain instances hereinafter in the illustrative examples, the purity of a synthesized product may be assessed with reference to its X-ray powder diffraction pattern. Thus, for example, if a sample is stated to be pure, it is intended only that the X-ray pattern of the sample is free of lines attributable to crystalline impurities, not that there are no amorphous materials present.
The molecular sieves of the instant invention may be characterized by their X-ray powder diffraction patterns and such may have one of the X-ray patterns set forth in the following Tables A through W, wherein said X-ray patterns are for the as-synthesized form unless otherwise noted. In most cases, the pattern of the corresponding calcined form will also fall within the relevant table. However, in some cases the removal of the occluded templating agent which occurs during calcination will be accompanied by sufficient relaxation of the lattice to shift some of the lines slightly outside the ranges specified in the relevant table. In a small number of cases, calcination appears to cause more substantial distortion in the crystal lattice, and hence, more significant changes in the X-ray powder diffraction pattern.
TABLE A______________________________________(AsAPSO-5)2.theta. d(.ANG.) Relative Intensity______________________________________7.2-7.7 12.28-11.48 m-vs19.4-19.9 4.58-4.46 w-m20.85-21.3 4.26-4.17 w-vs22.1-22.6 4.02-3.93 m-vs25.6-26.1 3.480-3.414 vw-m______________________________________
TABLE B______________________________________(AsAPSO-11)2.theta. d(.ANG.) Relative Intensity______________________________________7.8-8.2 11.19-10.85 m-s9.0-9.8 9.83-9.03 vw-vs12.8-13.6 6.92-6.51 vw-m19.9-20.5 4.46-4.33 m-s20.8-21.8 4.27-4.08 m-vs22.0-22.5 4.04-3.93 m-vs22.5-23.1 3.93-3.85 vw-vs23.1-23.5 3.85-3.79 w-vs______________________________________
TABLE C______________________________________(AsAPSO-14)2.theta. d(.ANG.) Relative Intensity______________________________________8.6-8.9 10.3-9.93 vs13.0 6.81 w21.9-22.2 4.06-4.00 w25.4 3.51 w27.5 3.24 w29.7 3.01 w______________________________________
TABLE D______________________________________(AsAPSO-16)2.theta. d(.ANG.) Relative Intensity______________________________________11.3-11.6 7.83-7.63 w-vs18.55-18.9 4.78-4.70 vw-m21.85-22.2 4.07-4.00 m-vs22.8-23.3 3.900-3.818 w-m26.4-27.3 3.370-3.267 w-m29.6-29.9 3.018-2.988 w-m______________________________________
TABLE E______________________________________(AsAPSO-17)2.theta. d(.ANG.) Relative Intensity______________________________________7.70-7.75 11.5-11.4 vs13.4 6.61 s-vs 15.5-15.55 5.72-5.70 s19.65-19.7 4.52-4.51 w-s20.5-20.6 4.33-4.31 vs 31.8-32.00 2.812-2.797 w-s______________________________________
TABLE F______________________________________(AsAPSO-18)2.theta. d(.ANG.) Relative Intensity______________________________________ 9.6-9.65 9.21-9.16 vs 15.5-15.55 5.72-5.70 m16.9-17.1 5.25-5.19 m20.15-20.25 4.41-4.39 m20.95-21.05 4.24-4.22 m31.8-32.5 2.814-2.755 m______________________________________
TABLE G______________________________________(AsAPSO-20)2.theta. d(.ANG.) Relative Intensity______________________________________13.8-14.2 6.42-6.23 m-vs 19.6-20.15 6.53-4.41 m24.1-24.7 3.695-3.603 m-vs27.9-28.6 3.198-3.121 w 31.3-32.05 2861-2.791 w34.35-35.0 2.610-2.601 w-m______________________________________
TABLE H______________________________________(AsAPSO-31)2.theta. d(.ANG.) Relative Intensity______________________________________8.4-9.5 10.53-9.31 w-s20.2-20.4 4.40-4.35 m22.0-22.1 4.040-4.022 m22.5-22.7 3.952-3.92 vs31.6-31.8 2.831-2.814 w-m______________________________________
TABLE J*______________________________________(AsAPSO-33)2.theta. d(.ANG.) Relative Intensity______________________________________9.25-9.55 9.56-9.26 w-m12.5-12.9 7.08-6.86 vs16.9-17.3 5.25-5.13 w-m20.45-20.9 4.34-4.25 w-m23.85-24.25 3.73-3.67 w-m26.05-26.35 3.42-3.38 w-m27.3-27.6 3.27-3.23 vs______________________________________ *as-synthesized form
TABLE K*______________________________________(AsAPSO-33)2.theta. d(.ANG.) Relative Intensity______________________________________13.15-13.4 6.73-6.61 vs18.05-18.35 4.91-4.83 m18.4-18.6 4.82-4.77 m26.55-26.7 3.36-3.34 m32.0-32.1 2.80-2.79 m______________________________________ *calcined form
TABLE L______________________________________(AsAPSO-34)2.theta. d(.ANG.) Relative Intensity______________________________________9.3-9.8 9.51-9.03 m-vs12.6-13.2 7.03-6.71 w-m15.8-16.3 5.61-5.44 vw-m20.25-21.2 4.39-4.19 w-vs24.8-25.4 3.59-3.507 vw-m30.0-30.9 2.979-2.894 vw-m______________________________________
TABLE M______________________________________(AsAPSO-35)2.theta. d (.ANG.) Relative Intensity______________________________________10.6-11.1 8.35-7.97 vw-vs13.1-13.7 6.76-6.46 vw-vs17.0-17.6 5.22-5.04 w-s 20.6-21.25 4.31-4.18 vw-m21.6-22.3 4.11-3.99 m-vs28.1-28.8 3.175-3.100 vw-m______________________________________
TABLE N______________________________________(AsAPSO-36)2.theta. d (.ANG.) Relative Intensity______________________________________7.45-8.0 11.14-11.05 vs8.1-8.3 10.91-10.65 w-m16.3-16.6 5.44-5.34 w-m18.9-19.4 4.70-4.57 w-m20.7-21.0 4.29-4.23 w-m______________________________________
TABLE O______________________________________(AsAPSO-37)2.theta. d (.ANG.) Relative Intensity______________________________________6.1-6.3 14.49-14.03 vs15.5-15.7 5.72-5.64 w-m18.5-18.8 4.80-4.72 w-m23.5-23.7 3.79-3.75 w-m26.9-27.1 3.31-3.29 w-m______________________________________
TABLE P______________________________________(AsAPSO-39)2.theta. d (.ANG.) Relative Intensity______________________________________9.2-9.6 9.61-9.21 m13.1-13.5 6.76-6.56 m17.8-18.4 4.98-4.82 w-m20.8-21.3 4.27-4.17 m-vs 22.2-22.85 4.00-3.892 m-vs 26.4-27.05 3.376-3.296 w-m______________________________________
TABLE Q______________________________________(AsAPSO-40)2.theta. d (.ANG.) Relative Intensity______________________________________7.5-7.7 11.79-11.48 vw-m8.0-8.1 11.05-10.94 s-vs12.4-12.5 7.14-7.08 w-vs13.6-13.8 6.51-6.42 m-s14.0-14.1 6.33-6.28 w-m27.8-28.0 3.209-3.187 w-m______________________________________
TABLE R______________________________________(AsAPSO-41)2.theta. d (.ANG.) Relative Intensity______________________________________13.6-13.8 6.51-6.42 w-m20.5-20.6 4.33-4.31 w-m21.1-21.3 4.21-4.17 vs22.1-22.3 4.02-3.99 m-s22.8-23.0 3.90-3.86 m23.1-23.4 3.82-3.80 w-m25.5-25.9 3.493-3.44 w-m______________________________________
TABLE S______________________________________(AsAPSO-42)2.theta. d (.ANG.) Relative Intensity______________________________________7.15-7.4 12.36-11.95 m-vs12.5-12.7 7.08-6.97 m-s21.75-21.9 4.09-4.06 m-s 24.1-24.25 3.69-3.67 vs27.25-27.4 3.273-3.255 s30.05-30.25 2.974-2.955 m-s______________________________________
TABLE T______________________________________(AsAPSO-43)2.theta. d (.ANG.) Relative Intensity______________________________________ 12.3-12.95 7.20-6.83 m-vs 16.8-17.45 5.28-5.09 vw-w21.45-21.85 4.145-4.071 m-vs 27.1-27.85 3.291-3.232 w-vs32.4-33.2 2.763-2.699 vw-m______________________________________
TABLE U______________________________________(AsAPSO-44)2.theta. d (.ANG.) Relative Intensity______________________________________9.2-9.6 9.61-9.21 m-vs15.9-16.3 5.57-5.44 vw-m20.5-21.0 4.33-4.23 m-vs24.3-25.1 3.66-3.548 w-m30.5-31.1 2.931-2.876 vw-m______________________________________
TABLE V______________________________________(AsAPSO-46)2.theta. d (.ANG.) Relative Intensity______________________________________7.2-8.1 12.28-10.92 vs12.9-13.6 6.86-6.51 vw21.2-22.2 4.19-1.501 vw-m 22.5-23.45 3.95-3.793 vw-m26.6-27.9 3.351-3.198 vw-m______________________________________
TABLE W______________________________________(AsAPSO-47)2.theta. d (.ANG.) Relative Intensity______________________________________9.4-9.6 9.41-9.21 vs12.8-13.1 6.92-6.76 vw-m16.0-16.3 5.54-5.44 vw-m20.5-21.0 4.31-4.23 m-vs24.6-25.3 3.613-3.526 vw-m30.6-31.1 2.921-2.876 vw-m______________________________________
The following examples are provided to further illustrate the invention and are not intended to be limiting thereof:
EXAMPLE 1
(Preparation of AsAPSO-5)
(a) AsAPSO-5 is prepared from a reaction mixture having a composition, expressed in terms of the molar oxide ratios of the components of the reaction mixture, of:
1.0-2.0 TPA:0.1-0.2 As.sub.2 O.sub.q : 0.5-1.0 Al.sub.2 O.sub.3 : 0.5-1.0 P.sub.2 O.sub.5 :0.1-0.6 SiO.sub.2 : 40-100 H.sub.2 O
where "TPA" denotes tripropylamine and "q" denotes the oxidation state of arsenic.
The reaction mixture is digested by placing the reaction mixture in a sealed stainless steel pressure vessel and heating it at an effective temperature and for an effective time to produce AsAPSO-5 product. Solids are recovered by filtration, washed with water and dried in air at room temperature.
The AsAPSO-5 product's chemical analysis shows the AsAPSO-5 product contains arsenic, aluminum, phosphorus and silicon in amounts within he pentagonal compositional area defined by points A, B, C, D and E of FIG. 1.
The X-ray powder diffraction pattern of a AsAPSO-5 product is characterized by the following data:
______________________________________2.theta. d (.ANG.) Relative Intensity______________________________________7.2-7.7 12.28-11.48 m-vs19.4-19.9 4.58-4.46 w-m20.8-21.3 4.26-4.17 w-vs22.1-22.6 4.02-3.93 m-vs25.6-26.1 3.480-3.414 vw-m______________________________________
(b) The X-ray powder diffraction pattern for a calcined AsAPSO-5 is also characterized by the X-ray pattern of part (a).
(c) When the calcined AsAPSO-5 of part (b) is utilized in adsorption capacity studies using a standard McBain-Bakr gravimetric adsorption apparatus the measurements are made on a sample after activation at 350.degree. C. in a vacuum. The following data are used in the adsorption studies:
______________________________________ Kinetic Pressure Wt. %Adsorbate Diameter (.ANG.) (Torr) Temp, .degree.C. Adsorbed*______________________________________O.sub.2 3.46 100 -183 7O.sub.2 3.46 750 -183 10Neopentane 6.2 700 24 4H.sub.2 O 2.65 4.3 24 4H.sub.2 O 2.65 20.0 24 12______________________________________ *typical amount adsorbed
The pore diameter of AsAPSO-5 is greater than about 6.2 .ANG..
EXAMPLE 2
(Preparation of AsAPSO-11)
(a) A solution was formed by dissolving 11.5 grams of arsenic(V) oxide (As.sub.2 O.sub.5) and 11.5 grams of 85 wt. percent orthophosphoric acid (H.sub.3 PO.sub.4) in 65.0 grams of water and heating. The resultant solution was cooled and then combined with 10.3 grams of hydrated aluminum oxide in the form of a pseudo-boehmite phase comprising 75.1 wt. percent Al.sub.2 O.sub.3 and 24.9 percent of H.sub.2 O. To this mixture was added 10.1 grams of di-n-propylamine (C.sub.6 H.sub.15 N) and the mixture was mixed until it was homogeneous. The resultant mixture was then divided into two equal portions and one portion was mixed with 3.0 grams of Ludox LS, a commercially available aqueous silica sol containing 30.0 wt. percent SiO.sub.2 to produce the final reaction mixture. The composition of the final reaction mixture, thus produced, expressed in terms of the molar oxide ratios of the components of the reaction mixture,
1.0 (C.sub.6 H.sub.15 N):0.5 As.sub.2 O.sub.5 : 0.75 Al.sub.2 O.sub.3 : 0.5 P.sub.2 O.sub.5 :0.3 SiO.sub.2 :40 H.sub.2 O.
This final reaction mixture was digested by placing the reaction mixture in a sealed stainless steel pressure vessel lined with polytetrafluoroethylene and heating it at an oven at 200.degree. C. under autogenous pressure for 18 hours. The solid reaction product (which was determined by the analyses described below to be mainly AsAPSO-11) was recovered by centrifugation, washed with water and dried in air at 100.degree. C.
A sample of this solid reaction product was analyzed and the following chemical analysis obtained:
______________________________________Component Weight percent______________________________________Carbon 2.7As.sub.2 O.sub.5 10.0Al.sub.2 O.sub.3 37.9P.sub.2 O.sub.5 34.3SiO.sub.2 9.0H.sub.2 O 7.0______________________________________
The above chemical analysis corresponds to a production composition of:
0.03 (C.sub.6 H.sub.15 N) (As.sub.0.06 Al.sub.0.51 P.sub.0.33 Si.sub.0.10)O.sub.2 : 0.27 H.sub.2 O.
Microprobe analysis of an aggregate of crystals having the morphology expected for AsAPSO-11 indicated the following relative proportions of arsenic, aluminum, phosphorus and silicon:
As.sub.0.04 P.sub.0.43 Si.sub.0.11
so that the product contained arsenic, aluminum, phosphorus and silicon in amounts within the pentagonal compositional area defined by points A, B, C, D and E of FIG. 1.
The product was not pure, but the X-ray powder diffraction pattern of the major phase, as synthesized, was characterized by the following Table BA (Hereinafter, Tables designated BA, BB etc. represent Tables containing all the peaks set forth in Table B above, and similarly for Tables LA, LB, etc.):
TABLE BA______________________________________(AsAPSO-11) Relative Intensity2.theta. d (.ANG.) 100 .times. I/I.sub.o______________________________________8.1 10.88 409.5 9.31 5913.2 6.71 1615.7 5.64 3716.3 5.43 420.4 4.36 7321.1 4.21 10022.2 4.01 5522.6 3.94 6822.7 3.91 61 (shoulder)23.2 3.83 7124.8 3.59 926.5 3.361 1528.3 3.155 1028.7 3.108 1331.6 2.831 1032.9 2.726 1334.3 2.616 736.4 2.469 537.9 2.373 1542.9 2.110 544.9 2.017 450.7 1.801 5______________________________________
The X-ray powder diffraction pattern of the major phase, after calcination by heating to 600.degree. C. in air for 2 hours was characterized by the data in the following Table BB:
TABLE BB______________________________________(AsAPSO-11) Relative Intensity2.theta. d (.ANG.) 100 .times. I/I.sub.o______________________________________8.0 10.95 409.6 9.19 4512.8 6.89 1415.9 5.57 3919.8 4.48 1221.5 4.13 10022.2 4.00 7522.5 3.96 6723.3 3.82 5125.9 3.445 826.6 3.347 1027.9 3.196 929.6 3.015 1332.6 2.748 1335.6 2.522 21______________________________________
Other specimens of AsAPSO-11 prepared in a similar manner had similar X-ray powder diffraction patterns. The following general Table BC summarizes the X-ray powder diffraction lines which were obtained from the various specimens of AsAPO-11; the least intense lines were not obtained from every specimen.
TABLE BC______________________________________(AsAPO-11) Relative Intensity2.theta. d (.ANG.) 100 .times. I/I.sub.o______________________________________8.1-8.2 10.83-10.88 27-409.5 9.31 40-5913.2-13.3 6.68-6.71 11-1615.7 5.63-5.64 22-3716.3 5.43 3-420.4 4.36 73-10021.1 4.21 70-10022.2 4.01 40-5522.6 3.94 6822.7-22.8 3.90-3.91 55-61 (shoulder)23.2 3.83 60-7124.8 3.59 6-926.5 3.361 10-1528.3 3.155 3-1028.7 3.108 10-1331.6 2.831 6-1032.9 2.726 8-1334.3 2.616 5-736.4-36.5 2.469 4-537.9 2.373 9-1542.9 2.110 544.8-44.9 2.017-2.021 3-4______________________________________
(b) A sample of the calcined product produced in part (a) was utilized in adsorption capacity studies using a standard McBain-Bakr gravimetric adsorption apparatus. Before being used in the adsorption tests, the sample was activated by heating to 350.degree. C. for 16 hours in vacuum. The following data were generated in the adsorption studies:
______________________________________ Kinetic Pressure Wt. %Adsorbate Diameter (.ANG.) (Torr) Temp, .degree.C. Adsorbed______________________________________O.sub.2 3.46 103 -183 6.1O.sub.2 3.46 750 -183 12.9Cyclohexane 6.0 11 21.6 2.7Cyclohexane 6.0 57 21.6 7.1n-Hexane 4.3 45 21.5 4.4iso-Butane 5.0 101 21.3 2.2H.sub.2 O 2.65 4.6 21.4 8.1H.sub.2 O 2.65 18.0 21.6 18.5______________________________________
From the above data, the pore size of the calcined product was determined to be greater than or equal to 6.ANG., as shown by the adsorption of cyclohexane (kinetic diameter of 6.0.ANG.).
EXAMPLE 3
(Preparation of AsAPSO-17)
(a) AsAPSO-17 is prepared from a reaction mixture having a composition, expressed in terms of the molar oxide ratios of the components of the reaction mixture, of:
1.0-2.0 QN:0.5-0.2 As.sub.2 O.sub.q : 0.5-1.0 Al.sub.2 O.sub.3 : 0.5-1.0 P.sub.2 O.sub.5 : 0.1-0.6 SiO.sub.2 :40-100 H.sub.2 O
where "QN" denotes quinuclidine and "q" denotes the oxidation state of arsenic
The reaction mixture is digested by placing the reaction mixture in a sealed stainless steel pressure vessel and heating it at an effective temperature and for an effective time to produce AsAPSO-17 product. Solids are then recovered by filtration, washed with water and dried in air at room temperature.
The AsAPSO-17 product's chemical analysis shows the AsAPSO-17 product contains arsenic aluminum, phosphorus and silicon in amounts within the pentagonal compositional area defined by points A, B, C, D and E of FIG. 1.
The X-ray powder diffraction pattern of a AsAPSO-17 product is characterized by the following data:
______________________________________2.theta. d(.ANG.) Relative Intensity______________________________________7.70-7.75 11.5-11.4 vs13.4 6.61 s- vs 15.5-15.55 5.72-5.70 s19.65-19.7 4.52-4.51 w- s20.5-20.6 4.33-4.31 vs31.8-32.0 2.812-2.797 w- s______________________________________
(b) The X-ray powder diffraction pattern for a calcined AsAPSO-17 is also characterized by the X-ray pattern of part (a).
(c) When the calcined AsAPSO-17 of part (b) is utilized in adsorption capacity studies using a standard McBain-Bakr gravimetric adsorption apparatus the measurements are made on a sample after activation at 350.degree. C. in a vacuum. The following data are used in the adsorption studies:
______________________________________ Kinetic Pressure Wt. %Adsorbate Diameter (.ANG.) (Torr) Temp, .degree.C. Adsorbed*______________________________________O.sub.2 3.46 100 -183 10O.sub.2 3.46 750 -183 12n-Butane 4.3 100 24 4H.sub.2 O 2.65 4.3 24 13H.sub.2 O 2.65 20 24 14______________________________________ *typical amount adsorbed
The pore diameter of AsAPSO-17 is about 4.3 .ANG..
EXAMPLE 4
(Preparation of AsAPSO-31)
(a) AsAPSO-31 is prepared from a reaction mixture having a composition, expressed in terms of the molar oxide ratios of the components of the reaction mixture, of:
1.0-2.0 DPA:0.05-0.2 As.sub.2 O.sub.q : 0.5-1.0 Al.sub.2 O.sub.3 : 0.5-1P.sub.2 O.sub.5 :0.1-0.6 SiO.sub.2 : 40-100 H.sub.2 O
where "DPA" denotes di-n-propylamine and "q" denotes the oxidation state of arsenic.
The reaction mixture is seeded with crystals of ALPO.sub.4 -31 (U.S. Pat. No. 4,310,440) and digested by placing the reaction mixture in a sealed stainless steel pressure vessel and heating it at an effective temperature and for an effective time to produce AsAPSO-31 product. Solids are then recovered by filtration, washed with water and dried in air at room temperature.
The AsAPSO-31 product's chemical analysis shows the AsAPSO-31 product contains arsenic, aluminum, phosphorus and silicon in amounts within the pentagonal compositional area defined by points A, B, C, D and E of FIG. 1.
The X-ray powder diffraction pattern of a AsAPSO-3 product is characterized by the following data:
______________________________________2.theta. d(.ANG.) Relative Intensity______________________________________8.4-9.5 10.53-9.31 w- s20.2-20.4 4.40-4.35 m22.0-22.1 4.040-4.022 m22.5-22.7 3.952-3.92 vs31.6-31.8 2.831-2.814 w- m______________________________________
(b) The X-ray powder diffraction pattern for a calcined AsAPSO-31 is also characterized by the X-ray data of part (a).
(c) When the calcined AsAPSO-31 of part (b) is utilized in adsorption capacity studies using a standard McBain-Bakr gravimetric adsorption apparatus the measurements are made on a sample after activation at 350.degree. C. in a vacuum. The following data are used in the adsorption studies:
______________________________________ Kinetic Pressure Wt. %Adsorbate Diameter (.ANG.) (Torr) Temp, .degree.C. Adsorbed*______________________________________O.sub.2 3.46 100 -183 4O.sub.2 3.46 750 -183 6Cyclohexane 6.0 90 24 3Neopentane 6.2 700 24 3H.sub.2 O 2.65 4.3 24 3H.sub.2 O 2.65 20 24 10______________________________________ *typical amount adsorbed
The pore diameter of AsAPSO-31 is greater than about 6.2 .ANG..
EXAMPLE 5
(Preparation of AsAPSO-34)
(a) A solution was formed by dissolving 11.5 grams of arsenic(V) oxide (As.sub.2 O.sub.5) and 11.5 grams of 85 wt. percent orthophosphoric acid (H.sub.3 PO.sub.4) in 48.1 grams of water with heating. The resultant solution was cooled and then combined with 30.6 grams of aluminum isopropoxide. The resultant mixture was stirred until homogeneous. To the resultant gel were added 72.0 grams of a 40 percent aqueous solution of tetraethylammonium hydroxide (TEAOH) and the gel was mixed until homogeneous. To this mixture were added 6.0 grams of Ludox LS, a commercially-available aqueous silica sol containing 30 wt. percent of SiO.sub.2, and the resultant mixture was mixed until homogeneous. The composition of the final reaction mixture thus produced, expressed in terms of the molar oxide ratios of the components of the reaction mixture, was:
2.0 TEAOH:0.5 As.sub.2 O.sub.5 :0.75 Al.sub.2 O.sub.3 :0.3 SiO.sub.2 : 0.5 P.sub.2 O.sub.5 :52 H.sub.2 O: 4.5 i-C.sub.3 H.sub.7 OH.
This final reaction mixture was digested by sealing it in a stainless steel pressure vessel lined with polytetrafluoroethylene and heating it in an oven at 200.degree. C. under autogenous pressure for 208 hours. The solid reaction product (which was determined by the analyses described below to be mainly AsAPSO-34 was recovered by centrifugation, washed with water and dried in air at 100.degree. C.
A sample of this solid reaction product was analyzed and the following chemical analysis obtained:
______________________________________Component Weight percent______________________________________Carbon 9.1As.sub.2 O.sub.5 11.1Al.sub.2 O.sub.3 32.4P.sub.2 O.sub.5 32.2SiO.sub.2 6.9H.sub.2 O 7.5______________________________________
The above chemical analysis corresponds to a product composition of:
0.07 TEAOH: (As.sub.0.07 Al.sub.0.49 P.sub.0.35 Si.sub.0.09)O.sub.2 : 0.32 H.sub.2 O
Microprobe analysis of a clean crystal having the morphology expected for AsAPSO-34 indicated the following relative proportions of arsenic, aluminum, phosphorus and silicon:
As.sub.0.09 Al.sub.0.44 P.sub.0.36 Si.sub.0.11
so that the product contained arsenic, aluminum silicon and phosphorus in amounts within the pentagonal compositional area defined by points A, B, C, D, E and F of FIG. 1.
The product was not pure, but the X-ray powder diffraction pattern of the major phase, as synthesized, was characterized by the data in the following Table LA:
______________________________________TABLE LA (AsAPSO-34) Relative Intensity2.theta. d(.ANG.) 100 .times. I/I.sub.o______________________________________9.5 9.35 10012.8 6.93 1314.0 6.33 1015.9 5.56 4217.9 4.96 1419.6 4.53 220.5 4.33 7022.1 4.03 423.0 3.87 425.1 3.552 1825.7 3.462 1327.5 3.244 228.2 3.161 229.4 3.037 430.4 2.938 2331.1 2.878 1732.2 2.783 334.3 2.617 436.1 2.490 342.9 2.110 343.2 2.096 347.3 1.921 248.8 1.867 550.7 1.800 352.9 1.730 255.5 1.654 3______________________________________
The X-ray powder diffraction pattern of the major phase, after calcination by heating to 390.degree. C. in a vacuum for 16 hours, was characterized by the data in the following Table LB:
______________________________________TABLE LB (AsAPSO-34) Relative Intensity2.theta. d(.ANG.) 100 .times. I/I.sub.o______________________________________9.6 9.25 10013.0 6.81 2116.2 5.48 1517.8 4.98 719.2 4.63 320.8 4.27 2623.2 3.83 525.0 3.564 826.2 3.406 928.0 3.189 428.2 3.160 229.9 2.987 330.9 2.893 1931.2 2.867 1234.8 2.579 3______________________________________
Other specimens of AsAPSO-34 prepared in a similar manner had similar X-ray powder diffraction patterns. The following general Table LC summarizes the X-ray powder diffraction lines which were obtained from the various specimens of AsAPSO-34, the least intense lines were not obtained from every specimen.
______________________________________TABLE LC (AsAPSO-34) Relative Intensity2.theta. d(.ANG.) 100 .times. I/I.sub.o______________________________________ 9.5 9.35 10012.8 6.93 9-1314.0 6.33 7-1015.9 5.56 28-4217.9 4.96 8-1419.6-19.7 4.52-4.53 220.5 4.33 47-7022.0-22.1 4.03-4.04 3-422.9-23.0 3.87-3.88 425.0-25.1 3.552-3.559 10-1825.7 3.462 10-1327.5 3.244 228.1-28.2 3.161-3.170 229.4 3.037 3-430.4 2.938 16-2331.0-31.1 2.878-2.882 13-1732.1-32.2 2.783-2.786 2-334.2-32.3 [???] 2.617-2.621 436.0-36.1 2.490-2.495 342.9-43.1 2.100-2.110 343.1-43.2 2.096-23.100 1-347.3 1.921 1-248.8-48.9 1.863-1.867 3-550.6-50.7 1.800-1.804 2-352.8-52.9 1.730-1.735 2______________________________________
(b) A sample of the calcined product produced in part (a) was utilized in adsorption capacity studies using a standard McBain-Bakr gravimetric adsorption apparatus. Before being used in the adsorption tests, the sample was activated by heating to 350.degree. C. for 16 hours in vacuum. The following data were generated in the adsorption studies:
______________________________________ Kinetic Pressure Wt. %Adsorbate Diameter (.ANG.) (Torr) Temp, .degree.C. Adsorbed______________________________________O.sub.2 3.46 103 -183 22.0O.sub.2 3.46 750 -183 28.7n-Hexane 4.3 45 21.5 10.2iso-Butane 5.0 101 21.3 0.3H.sub.2 O 2.65 4.6 21.4 27.8H.sub.2 O 2.65 18.0 21.6 33.9______________________________________
From the above data, the pore size of the calcined product was determined to be greater than 4.3 .ANG., as shown by the adsorption of n-hexane (kinetic diameter of 4.3 .ANG., but less than 5.0 .ANG., as shown by the low adsorption of iso-butane (kinetic diameter of 5.0 .ANG.).
EXAMPLE 6
(Preparation of AsAPSO-44)
(a) AsAPSO-44 is prepared from a reaction mixture having a composition, expressed in terms of the molar oxide ratios of the components of the reaction mixture, of:
1.0-2.0 CHA:0.05-0.2 As.sub.2 O.sub.q : 0.5-1 0 Al.sub.2 O.sub.3 : 0.5-1.0 P.sub.2 O.sub.5 :0.1-0.6 SiO.sub.2 : 40-100 H.sub.2 O
where "CHA" denotes cyclohexylamine and "q" denotes the oxidation state of arsenic.
The reaction mixture is digested by placing the reaction mixture in a sealed stainless steel pressure vessel and heating it at an effective temperature and for an effective time to produce AsAPSO-44 product. Solids are then recovered by filtration, washed with water and dried in air at room temperature.
The AsAPSO-44 product's chemical analysis shows the AsAPSO-44 product contains arsenic, aluminum, phosphorus and silicon in amounts within the pentagonal compositional area defined by points A, B, C, D and E of FIG. 1.
The X-ray powder diffraction pattern of a AsAPSO-44 product is characterized by the following data:
______________________________________2.theta. d(.ANG.) Relative Intensity______________________________________ 9.2-9.6 9.61-9.21 m- vs15.9-16.3 5.57-5.44 vw- m20.5-21.0 4.33-4.23 m- vs24.3-25.1 3.66-3.548 w- m30.5-31.1 2.931-2.876 vw- m______________________________________
(b) When the calcined AsAPSO-44 is utilized in adsorption capacity studies using a standard McBain-Bakr gravimetric adsorption apparatus the measurements are made on a sample after activation at 350.degree. C. in a vacuum. The following data are used in the adsorption studies:
______________________________________ Kinetic Pressure Wt. %Adsorbate Diameter (.ANG.) (Torr) Temp, .degree.C. Adsorbed*______________________________________O.sub.2 3.46 100 -183 13O.sub.2 3.46 750 -183 16n-Hexane 4.3 100 24 2H.sub.2 O 2.65 4.3 24 15H.sub.2 O 2.65 20 24 17______________________________________ *typical amount adsorbed
The pore diameter of AsPSO-44 is about 4.3.ANG..
EXAMPLE 7
(Preparation of AsAPSO-35)
(a) A solution was formed by dissolving 11.5 grams of arsenic(V) oxide (As.sub.2 O.sub.5) and 11.5 grams of 85 wt. percent orthophosphoric acid (H.sub.3 PO.sub.4) in 42.9 grams of water with heating. The resultant solution was cooled and then combined with 33.4 grams of quinuclidine (QN). The resultant solution was combined with a gel prepared by mixing 32.5 grams of 50 wt. percent aqueous aluminum chlorhydrol (Al.sub.2 (OH).sub.5 Cl . 2.5 H.sub.2 O; Al.sub.2 O.sub.3 content 23.5 wt. percent) and 12.0 grams of Ludox LS, a commercially-available aqueous silica sol containing 30 wt. percent of SiO.sub.2. The resultant mixture was mixed until homogeneous. The composition of the final reaction mixture thus produced, expressed in terms of the molar oxide ratios of the components of the reaction mixture, was:
3.0 QN:0.50 As.sub.2 O.sub.5 : 0.75 Al.sub.2 O.sub.3 : 0.50 P.sub.2 O.sub.5 :60 SiO.sub.2 :40 H.sub.2 O.
This final reaction mixture was digested by sealing it in a stainless steel pressure vessel lined with polytetrafluoroethylene and heating it in an oven at 150.degree. C. under autogenous pressure for 188 hours. The solid reaction product (which was determined by the analyses described below to be AsAPSO-35) was recovered by centrifugation, washed with water, and dried in air at 100.degree. C.
A sample of this solid reaction product was analyzed and the following chemical analysis obtained:
______________________________________Component Weight percent______________________________________Carbon 13.3As.sub.2 O.sub.5 4.6Al.sub.2 O.sub.3 29.7P.sub.2 O.sub.5 32.6SiO.sub.2 12.9H.sub.2 O 6.3______________________________________
The above chemical analysis corresponds to an empirical chemical composition of:
0.12 QN:(As.sub.0.03 Al.sub.0.45 P.sub.0.35 Si.sub.0.17)O.sub.2 :0.27 H.sub.2 O.
Microprobe analysis of clean crystals having the morphology expected for AsAPSO-35 indicated the following relative proportions of arsenic, aluminum, phosphorus and silicon:
As.sub.0.04 Al.sub.0.46 P.sub.0.33 Si.sub.0.17
so that the product contained arsenic, aluminum, phosphorus and silicon in amounts within the pentagonal compositional area defined by points A, B, C, D and E of FIG. 1.
The product was not pure, but the X-ray powder diffraction pattern of the major phase, as synthesized, was characterized by the data in the following Table MA:
TABLE MA______________________________________(AsAPSO-35) Relative Intensity2.theta. d(.ANG.) 100 .times. I/I.sub.o______________________________________8.6 10.25 1711.0 8.06 6111.8 7.51 613.3 6.66 2715.9 5.58 717.3 5.13 7617.8 4.98 1521.2 4.20 8621.9 4.07 10022.2 4.01 9 (shoulder)22.7 3.92 623.1 3.85 1923.7 3.76 1125.1 3.552 826.8 3.332 1728.5 3.132 2928.8 3.103 3731.3 2.854 3 (shoulder)32.0 2.796 4334.6 2.591 1235.7 2.518 537.6 2.392 240.7 2.216 242.1 2.145 542.3 2.134 443.0 2.102 548.5 1.878 1149.3 1.849 551.4 1.777 955.1 1.666 6______________________________________
The X-ray powder diffraction pattern of the major phase, after calcination by heating at 600.degree. C. in air for 2.25 hours, was characterized by the data in the following Table MB:
TABLE MB______________________________________ (AsAPSO-35) Relative Intensity2.theta. d(.ANG.) 100 .times. I/I.sub.o______________________________________8.8 10.07 1511.1 7.98 10011.7 7.54 9 (shoulder)13.6 6.50 8817.6 5.05 2721.1 4.21 3822.3 3.99 5523.0 3.86 823.6 3.76 1525.2 3.538 1626.2 3.407 827.4 3.260 1828.6 3.116 4929.6 3.020 931.7 2.818 932.7 2.741 2534.7 2.586 835.5 2.529 651.8 1.766 6______________________________________
Other specimens of AsAPSO-35 prepared in a similar manner had similar X-ray powder diffraction patterns. The following general Table MC summarizes the X-ray powder diffraction lines which were obtained from the various specimens of AsAPSO-35; the least intense lines were not obtained from every specimen.
TABLE MC______________________________________ (AsAPSO-35) Relative Intensity2.theta. d(.ANG.) 100 .times. I/I.sub.o______________________________________8.5-8.6 10.25-10.37 12-1710.9-11.0 8.06-8.11 61-6211.8-12.1 7.33-7.51 5-613.2-13.3 6.66-6.69 22-2715.8-15.9 5.58-5.61 717.2-17.3 5.13-5.15 54-7617.7-15.8 4.98-5.02 10-1521.1-21.2 4.20-4.22 36-8621.8-21.9 4.07-4.08 10022.2 4.01 9-50 (shoulder)22.7 3.92 623.1 3.85 19-2723.7 3.76 1125.1 3.552 826.7-26.8 3.332-3.338 17-1828.5 3.132 19-2928.7-28.8 3.103-3.112 20-3731.3 2.854 3 (shoulder)32.0 2.796 27-4334.6-34.7 2.586-2.591 7-1235.7 2.518 537.6 2.392 240.7 2.216 242.1 2.145 542.3 2.134 443.0 2.102 548.5 1.878 8-1149.3 1.849 5-651.4 1.777 955.1 1.666 6______________________________________
(b) A sample of the calcined product produced in part (a) was utilized in adsorption capacity studies using a standard McBain-Bakr gravimetric adsorption apparatus. Before being used in the adsorption tests, the sample was activated by heating to 350.degree. C. for 16 hours in vacuum. The following data were generated in the adsorption studies:
______________________________________ Kinetic Pressure Wt. %Adsorbate Diameter (.ANG.) (Torr) Temp, .degree.C. Adsorbed______________________________________O.sub.2 3.46 100 -183 14.0O.sub.2 3.46 750 -183 18.5H.sub.2 O 2.65 4.6 21.4 21.0H.sub.2 O 2.65 18.0 21.6 28.6n-Hexane 4.3 45 21.5 6.2iso-Butane 5.0 101 21.3 0.7______________________________________From the above data, the pore calcined product Was determined to begreater than about 4.3.ANG., as shown by the adsorption of n-hexane(kinetic diameter of 4.3.ANG.), but less than about 5.0.ANG. as shown bythe negligible adsorption of iso-butane (kinetic diameter of 5.0.ANG.).
The AsAPSO compositions of the present invention are, in general, hydrophilic and adsorb water preferentially over common hydrocarbon molecules such as paraffins, olefins and aromatic species, e.g., benzene, xylenes and cumene. Thus the present molecular sieve compositions as a class are useful as desiccants in such adsorption separation/purification processes as natural gas drying, cracked gas drying. Water is also preferentially adsorbed over the so-called permanent gases such as carbon dioxide, nitrogen, oxygen and hydrogen. These AsAPSOs are therefore suitably employed in the drying of reformer hydrogen streams and in the drying of oxygen, nitrogen or air prior to liquifaction.
The present AsAPSO compositions also exhibit novel surface selectivity characteristics which render them useful as catalyst or catalyst bases in a number of hydrocarbon conversion and oxidative combustion reactions. They can be impregnated or otherwise loaded with catalytically active metals by methods well known in the art and used, for example, in fabricating catalyst compositions having silica or alumina bases. Of the general class, those species having pores larger than about 4A are preferred for catalytic applications.
Among the hydrocarbon conversion reactions catalyzed by AsAPSO compositions are cracking, hydrocracking, alkylation for both the aromatic and isoparaffin types, isomerization including xylene isomerization, polymerization, reforming, hydrogenation, dehydrogenation, transalkylation, dealkylation, hydrodecyclization and dehydrocyclization.
Using AsAPSO catalyst compositions which contain a hydrogenation promoter such as platinum or palladium, heavy petroleum residual stocks, cyclic stocks and other hydrocrackable charge stocks, can be hydrocracked at temperatures in the range of 400.degree. F. to 825.degree. F. (204.degree. C. to 441.degree. C.) using molar ratios of hydrogen to hydrocarbon in the range of between 2 and 80, pressures between 10 and 3500 p.s.i.g. (0.171 to 24.23 MPa.), and a liquid hourly space velocity (LHSV) of from 0.1 to 20, preferably 1.0 to 10.
The AsAPSO catalyst compositions employed in hydrocracking are also suitable for use in reforming processes in which the hydrocarbon feedstocks contact the catalyst at temperatures of from about 700.degree. F. to 1000.degree. F. (371.degree. C. to 538.degree. C.), hydrogen pressures of from 100 to 500 p.s.i.g. (0.791 to 3.448 MPa.), LHSV values in the range of 0.1 to 10 and hydrogen to hydrocarbon molar ratios in the range of 1 to 20, preferably between 4 and 12.
These same catalysts, i.e. those containing hydrogenation promoters, are also useful in hydroisomerization processes in which feedstocks such as normal paraffins are converted to saturated branched chain isomers. Hydroisomerization is carried out at a temperature of from about 200.degree. F. to 600.degree. F. (93.degree. C. to 316.degree. C.), preferably 300.degree. F. to 550.degree. F. (149.degree. C. to 288.degree. C.) with an LHSV value of from about 0.2 to 1.0. Hydrogen (H) is supplied to the reactor in admixture with the hydrocarbon (Hc) feedstock in molar proportions (H/Hc) of between 1 and 5.
At somewhat higher temperatures, i.e. from about 650.degree. F. to 1000.degree. F. (343.degree. C. to 538.degree. C.), preferably 850.degree. F. to 950 .degree. F. (454.degree. C. to 510.degree. C.) and usually at somewhat lower pressures within the range of about 15 to 50 p.s.i.g. (205 to 446 KPa.), the same catalyst compositions are used to hydroisomerize normal paraffins. Preferably the paraffin feedstock comprises normal paraffins having a carbon number range of C.sub.7 -C.sub.20. Contact time between the feedstock and the catalyst is generally relatively short to avoid undesirable side reactions such as olefin polymerization and paraffin cracking. LHSV values in the range of 0.1 to 10, preferably 1.0 to 6.0 are suitable.
The unique crystal structure of the present AsAPSO catalysts and their availability in a form totally void of alkali metal content favor their use in the conversion of alkylaromatic compounds, particularly the catalytic disproportionation of toluene, ethylene, trimethyl benzenes, tetramethyl benzenes and the like. In the disproportionation process, isomerization and transalkylation can also occur. Group VIII noble metal adjuvants alone or in conjunction with Group VI-B metals such as tungsten, molybdenum and chromium are preferably included in the catalyst composition in amounts of from about 3 to 15 weight-% of the overall composition. Extraneous hydrogen can, but need not, be present in the reaction zone which is maintained at a temperature of from about 400 to 750.degree. F. (204 to 399.degree. C.), pressures in the range of 100 to 2000 p.s.i.g. (0.791 to 13.89 MPa.) and LHSV values in the range of 0.1 to 15.
Catalytic cracking processes are preferably carried out with AsAPSO compositions using feedstocks such as gas oils, heavy naphthas, deasphalted crude oil residua, etc., with gasoline being the principal desired product. Temperature conditions of 850 to 1100.degree. F. (454 to 593.degree. C.), LHSV values of 0.5 to 10 and pressure conditions of from about 0 to 50 p.s.i.g. (101 to 446 KPa.) are suitable.
Dehydrocyclization reactions employing paraffinic hydrocarbon feedstocks, preferably normal paraffins having more than 6 carbon atoms, to form benzene, xylenes, toluene and the like are carried out using essentially the same reaction conditions as for catalytic cracking. For these reactions it is preferred to use the AsAPSO catalyst in conjunction with a Group VIII non-noble metal cation such as cobalt and nickel.
In catalytic dealkylation wherein it is desired to cleave paraffinic side chains from aromatic nuclei without substantially hydrogenating the ring structure, relatively high temperatures in the range of about 800.degree.-1000.degree. F. (427.degree.-538.degree. C.) are employed at moderate hydrogen pressures of about 300-1000 p.s.i.g. (2.17-6.895 MPa.), other conditions being similar to those described above for catalytic hydrocracking. Preferred catalysts are of the same type described above in connection with catalytic dehydrocyclization. Particularly desirable dealkylation reactions contemplated herein include the conversion of methylnaphthalene to naphthalene and toluene and/or xylenes to benzene.
In catalytic hydrofining, the primary objective is to promote the selective hydrodecomposition of organic sulfur and/or nitrogen compounds in the feed, without substantially affecting hydrocarbon molecules therein. For this purpose it is preferred to employ the same general conditions described above for catalytic hydrocracking, and catalysts of the same general nature described in connection with dehydrocyclization operations. Feedstocks include gasoline fractions, kerosenes, jet fuel fractions, diesel fractions, light and heavy gas oils, deasphalted crude oil residua and the like. Any of these may contain up to about 5 weight-percent of sulfur and up to about 3 weight-percent of nitrogen.
Similar conditions can be employed to effect hydrofining, i.e., denitrogenation and desulfurization, of hydrocarbon feeds containing substantial proportions of organonitrogen and organosulfur compounds. It is generally recognized that the presence of substantial amounts of such constituents markedly inhibits the activity of hydrocracking catalysts. Consequently, it is necessary to operate at more extreme conditions when it is desired to obtain the same degree of hydrocracking conversion per pass on a relatively nitrogenous feed than with a feed containing less organonitrogen compounds. Consequently, the conditions under which denitrogenation, desulfurization and/or hydrocracking can be most expeditiously accomplished in any given situation are necessarily determined in view of the characteristics of the feedstocks, in particular the concentration of organonitrogen compounds in the feedstock. As a result of the effect of organonitrogen compounds on the hydrocracking activity of these compositions it is not at all unlikely that the conditions most suitable for denitrogenation of a given feedstock having a relatively high organonitrogen content with minimal hydrocracking, e.g., less than 20 volume percent of fresh feed per pass, might be the same as those preferred for hydrocracking another feedstock having a lower concentration of hydrocracking inhibiting constituents e.g., organonitrogen compounds. Consequently, it has become the practice in this art to establish the conditions under which a certain feed is to be contacted on the basis of preliminary screening tests with the specific catalyst and feedstock.
Isomerization reactions are carried out under conditions similar to those described above for reforming, using somewhat more acidic catalysts. Olefins are preferably isomerized at temperatures of 500.degree.-900.degree. F. (260.degree.-482.degree. C.), while paraffins, naphthenes and alkyl aromatics are isomerized at temperatures of 700.degree.-1000.degree. F. (371.degree.-538.degree. C.). Particularly desirable isomerization reactions contemplated herein include the conversion of n-heptene and/or n-octane to isoheptanes, iso-octanes, butane to iso-butane, methylcyclopentane to cyclohexane, meta-xylene and/or ortho-xylene to paraxylene, 1-butene to 2-butene and/or isobutene, n-hexane to isohexene, cyclohexene to methylcyclopentene etc. The preferred form of the catalyst is a combination of the AsAPSO with polyvalent metal compounds (such as sulfides) of metals of Group II-A, Group II-B and rare earth metals. For alkylation and dealkylation processes the AsAPSO compositions having pores of at least 5.ANG. are preferred. When employed for dealkylation of alkyl aromatics, the temperature is usually at least 350.degree. F. (177.degree. C.) and ranges up to a temperature at which substantial cracking of the feedstock or conversion products occurs, generally up to about 700.degree. F. (371.degree. C.) The temperature is preferably at least 450.degree. F. (232.degree. C.) and not greater than the critical temperature of the compound undergoing dealkylation. Pressure conditions are applied to retain at least the aromatic feed in the liquid state. For alkylation the temperature can be as low as 250.degree. F. (121.degree. C.) but is preferably at least 350.degree. F. (177.degree. C.). In the alkylation of benzene, toluene and xylene, the preferred alkylating agents are olefins such as ethylene and propylene.

Number	Name	Date
3941871	Dwyer et al.	Mar 1976
4061724	Grose et al.	Dec 1977
4310440	Wilson et al.	Jan 1982
4397825	Whittam	Aug 1983
4420467	Whittam	Dec 1983
4440871	Lok et al.	Apr 1984
4456582	Marosi et al.	Jun 1984
4486397	Eshraghi et al.	Dec 1984
4500651	Lok et al.	Feb 1985
4554143	Messina et al.	Nov 1985
4564511	Desmond et al.	Jan 1986
4567029	Wilson et al.	Jan 1986

Number	Date	Country
0054364	Jun 1982	EPX
0055046	Jun 1982	EPX
0055529	Jul 1982	EPX
0059059	Sep 1982	EPX
0984502	Feb 1965	GBX

Arsenic-aluminum-phosphorus-silicon-oxide molecular sieve compositions

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Continuation in Parts (1)