Method for preparing zeolites

BACKGROUND OF THE INVENTION
The prior art described synthetic zeolites, different methods of preparing same and the use of synthetic or natural zeolites in the catalytic conversion of hydrocarbons. The zeolites according to the invention are very stable to heat and acids, what makes them particularly suited for processes involving high temperatures, such as isomerization of xylenes; other advantages will appear from the description.
DESCRIPTION OF THE INVENTION
The invention relates to a method for preparing zeolites having the formula: (1.5.+-.0.6) M.sub.2/n O.Al.sub.2 O.sub.3.ySiO.sub.2.zH.sub.2 O, where y ranges from 20 to 90, preferably from 40 to 80 and z from 2 to 12, preferably from 3 to 8, M is at least one cation and n is the valence of M, and where Al and Si may be optionally replaced, at least partially, by Ga and Ge respectively. M is preferably selected from the monovalent cations, the cations of the rare earths, the cations of the 2nd and 8th Groups of the Periodic System, and mixtures thereof; in particular the cations can be selected from alkaline ions, hydrogen ion, ammonium ion, diethyl-piperidinium ion and mixtures thereof. The formula of diethyl-piperidinium ion (DEPP).sup.+ is: ##STR1## The method according to the invention comprises the admixture of (DEPP)OH or of a salt thereof with H.sub.2 O and with at least one compound containing Na, one compound containing a metal selected from amongst Al, Ga and mixtures thereof and one compound containing an element selected from amongst Si, Ge and mixtures thereof, the molar ratios, expressed as oxides ratios, being comprised in the following ranges;
SiO.sub.2 :Al.sub.2 O.sub.3 =from 20 to 120 (preferably from 40 to 85)
Na.sub.2 O:SiO.sub.2 =from 0.07 to 0.50 (preferably from 0.07 to 0.25)
(DEPP).sub.2 O:SiO.sub.2 =from 0.05 to 0.50 (preferably from 0.10 to 0.20)
H.sub.2 O:Na.sub.2 O=from 50 to 600 (preferably from 150 to 400).
According to a preferred embodiment, the cation dilution ratios, namely the molar ratios:
r1=H.sub.2 O:(DEPP).sub.2 O (organic cation ratio)
r2=H.sub.2 O:[(DEPP).sub.2 O+Na.sub.2 O] (global cation ratio) are respectively equal to or higher than 160 (preferably 190) and 80 (preferably 90) and the r2:r1 ratio (namely the sodium factor SF) is equal to or lower than 0.6 (preferably between 0.20 and 0.60). A very important factor, the cation mineralization factor (CMF), defined as:
[(DEPP).sub.2 O+Na.sub.2 O]:[SiO.sub.2 +2Al.sub.2 O.sub.3 ]
should be higher than 0.20 (preferably from 0.22 to 0.38).
The synthesis can be carried out under autogenous pressure, in an autoclave equipped with stirrer, in one or more steps at, between 130.degree. to 200.degree. C. for one or more days, and preferably between 160.degree. to 200.degree. C.; the solid is then separated from the liquid, for instance by filtration or centrifugation. Sources of Si, Al, Ga, Ge and Na can be compounds providing for the corresponding oxides, such as Al silicates, Na aluminates, Na silicates, silica hydrosol, silica gel, silicic acid and NaOH; (DEPP).sup.++ ion can be provided for by the hydroxide, a halide (in particular bromide or iodide), a sulphate, a phosphate or the nitrate. Zeolites can undergo exchange of the original ion with the proton (from acids) or with the ammonium ion; it is possible to obtain zeolites in the acid form by exchange with ammonium (using for instance NH.sub.4 Cl, NH.sub.4 NO.sub.3 or NH.sub.4 OH) and by successive calcination of the zeolite. The ammonium ion decomposes and a proton is left in the structure; the protons (or the original ions) can be exchanged with all the cations of the Periodic System, in particular with the cations of the 8th group, according to known technologies. The new zeolites can be used in acid form or partially exchanged with different ions; it is possible to add active components by means of known techniques, such as dry or wet impregnation and mechanical mixing.
Zeolites can be prepared in a variety of shapes, for instance in granules or extrudates; in such cases it is advisable to admix the obtained powder with a binding material, such as clays, silica, alumina or other metal oxides. Before being used, zeolites should be at least partially dehydrated, for example by a heat-treatment at high temperatures, under vacuum or not; activation in the air, at temperatures from 450.degree. C. to the temperature at which the structural collapse of the zeolite starts (about 850.degree. C.) is recommendable.
The invention relates also to the use of the new zeolites for the conversion of hydrocarbons by means of acid-catalyzed reactions, such as cracking, hydrocracking, isomerization, aromatization, polymerization, reforming, alkylation, disproportionation and dealkylation, for which reactions a very high activity and selectivity have been determined.
When zeolites are used as catalysts, it is advisable to mix them with a binder such as silica, alumina, clays (in particular bentonite), metal oxides and in general all the binders considered in U.S. Pat. No. 3,702,886.
In such a case moreover, one can add metals having hydrogenating properties, like Ni or other metals of the VIII group, which can be added either by exchange or impregnation or by any other known technology. They lower the fouling of the catalyst and cause its life to be longer.
Best results have been obtained in the isomerization of meta-xylene to ortho and para isomers; isomerization of meta-xylene, optionally in admixture with ethylbenzene and with lower amounts of desired products (ortho- and para-xylene), can be carried out in vapor phase, in the presence of hydrogen (molar ratio H.sub.2 /hydrocarbon from 3 to 10), at temperatures from 250.degree. to 450.degree. C., preferably from 275.degree. to 420.degree. C., at pressures from 10 to 20 kg/cm.sup.2 and at space velocities from 1 to 10 volumes of liquid hydrocarbon per apparent volume of catalyst and per hour (LHSV=from 1 to 10, preferably from 2 to 8 h.sup.-1).
The following examples illustrate the invention, without being however a limitation thereof.

CONDITIONS COMMON TO ALL THE EXAMPLES
X-rays analysis was carried out by the powder diffraction method, using a wide-angle diffractometer equipped with a proportional counter with a discriminator of the pulse-height, using the K.sub..alpha. radiation of copper (.lambda.=1.54178 A), filtered with a nickel foil, and using the followng conditions:
______________________________________scanning rate: 1.degree. min.sup.-1, 1/4.degree. min.sup.-1divergence slit: .gamma. = 1.degree.receiving slit: .nu. = 0.1 mmtime constant 4 seconds.______________________________________
Heights I and angular positions of the diffraction peaks were deduced from the diffractograms; relative intensities 100 I/I.sub.o and interplanar distances "d" expressed in Angstrom were determined on the basis of height I.sub.o of the most intense diffraction peak and of diffraction angle 2.theta. of the recorded lines. Angle 2.theta., indicated by the goniometer, was calibrated by means of reflections (111), (311) and (620) of a high purity silicon standard (a.sub.o =5.43088 A). The exchange of Na.sup.+ ion with other cations and the activation treatment at 540.degree. C. provided crystalline products; the X-rays pattern did not show substantial variations, with respect to the Na.sup.+ form, but for a few little shifts in interplanar distances and for the relative intensities of the bands. The adsorption properties of zeolites towards vapors help to point out their structures, as suggested by Landolt G. R. [Anal. Chem. 43 (4), 613 (1971)]. As to the adsorption, H.sub.2 O, n-hexane and cyclohexane contact zeolite samples (degasified at 350.degree. C. under vacuum) at 25.degree. C., under a pressure lower than their vapor pressure at 25.degree. C. (22 torr for H.sub.2 O, 45 torr for n-hexane and 28 torr for cyclohexane). Difference of weight before and after adsorption indicated the value of the adsorption.*
*R. Le Van.Mao, React. Kinet Catal. Lett., Vol. 12 (1) 69-76 (1979)
EXAMPLE 1
75 g of (DEPP) Br, 3 g of Na aluminate and 7.5 g of NaOH were dissolved in 300 cm.sup.3 of H.sub.2 O. The solution was heated at 60.degree.-70.degree. C., whereupon 225 g of silica sol (Ludox AS) were added, and then again at a temperature from 60.degree. to 70.degree. C. under intense stirring for 10 minutes. Ludox AS is a colloidal aqueous solution containing 30.5% by weight of silica and 0.25% by weight of ammonia. The composition (by mols) was:
______________________________________SiO.sub.2 = 1.144 Na.sub.2 O = 0.113 (DEPP)Br = 0.338Al.sub.2 O.sub.3 = 0.017 H.sub.2 O = 25.4______________________________________
The gel was transferred into a Hastelloy C autoclave and heated at 150.degree. C. for 8 days and then at 175.degree. C. for 5 days, under stirring (30 rpm). After cooling, the suspension was discharged and filtered; the solid was washed until the washing liquid had a pH value lower than 9 and then dried at 120.degree. C. for 12 hours.
The product was crystalline and exhibited the X-rays pattern of Table 1; its chemical composition was (% by weight):
______________________________________Si = 40.7 Na = 0.9 C = 5.7Al = 1.2 H = 1.5 N = 0.7______________________________________
After activation in the air at 540.degree. C. for 10 hours, the solid exhibited the following vapor adsorption at 25.degree. C.:
______________________________________water = 10.4 b.w.n-hexane = 8.7 b.w. cyclohexane = 5.4 b.w.______________________________________
EXAMPLE 2 (acid form)
The compound, washed and dried at 120.degree. C. (but not activated) as in example 1, was poured into a flask equipped with a reflux cooler, in contact with an aqueous solution of NH.sub.4 Cl at 5% by weight, using 19 cm.sup.3 of solution per gram of zeolite. Under moderate stirring, the flask was heated at from 70.degree. to 80.degree. C. and kept at such temperature for 1 hour; after decantation, the operation was repeated four times using a fresh solution of NH.sub.4 Cl. At the end the compound was washed with distilled water until disappearance of the Cl.sup.- ions in the washing liquid, and dried at 120.degree. C. for 12 hours. Its composition (% by weight) was:
______________________________________Si = 41.7 Na = 0.2 C = 5.2Al = 1.0 H = 0.9 N = 0.8______________________________________
By activation of the compound in the air at 540.degree. C. for 10 hours, the acid form or "H-zeolite" was obtained; the X-rays diffraction pattern is reported on Table 2.
EXAMPLE 3
2.0 g of Na aluminate, 50 g of (DEPP) Br and 5 g of NaOH were dissolved in 200 cm.sup.3 of H.sub.2 O. We heated at 60.degree. C. and 150 g of silica sol (Ludox AS) were added; after intense stirring for 10 minutes, the gel, having the following composition by moles:
______________________________________SiO.sub.2 = 0.763 Na.sub.2 O = 0.075 (DEPP) Br = 0.225Al.sub.2 O.sub.3 = 0.011 H.sub.2 O = 16.9______________________________________
was transferred into the autoclave of example 1, where it was heated at 150.degree. C. for 8 days and then at 190.degree. C. for 6 days.
After discharge, the solid was washed and dried as in example 1. The product exhibited the diffraction pattern recorded in Table 3; its chemical composition (% by weight) was:
______________________________________Si = 41.1 Na = 0.5 C = 5.4Al = 1.15 H = 0.6 N = 0.7______________________________________
The solid, activated as in example 1, exhibited the following
______________________________________vapor adsorption at 25.degree. C.: water = 9.6% b.w.n-hexane = 8.2% b.w. cyclohexane = 4.5% b.w.______________________________________
EXAMPLE 4 (acid form)
The product, washed and dried at 120.degree. C. (but not activated) as in example 3, was exchanged with NH.sub.4.sup.+ (see example 2) and dried at 120.degree. C. for 12 hours. Its composition was (% by weight):
______________________________________Si = 41.7 Na = 0.2 C = 5.0Al = 1.15 H = 0.8 N = 0.8______________________________________
By activation of the compound as in example 2, the "H-zeolite" was obtained; the product, in acid form, showed the X-rays diffraction pattern of Table 4.
EXAMPLE 5
50 g of (DEPP) Br, 2 g of Na aluminate and 5 g of NaOH were dissolved in 250 cm.sup.3 of H.sub.2 O; the solution was heated at 60.degree.-70.degree. C., whereupon 150 g of silica sol (Ludox AS) were added. Heating of the mixture at 60.degree.-70.degree. C. was carried on under intense stirring for 10 minutes. The composition (by moles) was:
______________________________________SiO.sub.2 = 0.763 Na.sub.2 O = 0.075 (DEPP) Br = 0.225Al.sub.2 O.sub.3 = 0.011 H.sub.2 O = 19.7______________________________________
The gel was poured into the autoclave of example 1 and heated at 150.degree. C. for 9 days and then at 180.degree. C. for 5 days under stirring (30 rpm). After cooling, the suspension was discharged and filtered; the solid was washed and dried as in example 1. The product revealed the diffraction pattern shown in Table 5. Its composition was (% by weight):
______________________________________Si = 40.1 Na = 0.9 C = 4.4Al = 0.9 H = 0.4 N = 0.6______________________________________
The solid, activated as in example 1, exhibited the following
______________________________________water = 7.8% b.w.n-hexane = 5.7% b.w. cyclohexane = 4.3% b.w.______________________________________
EXAMPLE 6 (acid form)
The product, washed and dried at 120.degree. C. (but not activated) as in example 5, was exchanged with NH.sub.4.sup.+ (see example 2) and dried at 120.degree. C. for 12 hours. Its composition was (% by weight):
______________________________________Si = 42.5 Na = 0.2 C = 3.9Al = 1.0 H = 0.5 N = 0.7______________________________________
By activation of the product as in example 2, the "H-zeolite" was obtained; the product, in acid form, showed the X-rays diffraction pattern of Table 6.
EXAMPLE 7
The zeolites in the acid form obtained in examples 2, 4 and 6 were mixed with 10% by weight of bentonite, homogenously kneaded with a suitable amount of water and extruded in pieces having a diameter of 1 mm; the product was then dried for 12 hours between 100.degree. and 120.degree. C. and for 2 hours at 540.degree. C. The resulting catalyst was used in the isomerization of meta-xylene, either as such or in admixture with about 10% by weight of ethylbenzene (see Table 7). To this purpose, 30 cm.sup.3 of catalysts were charged into a steel reactor having an inside diameter of 16 mm, electrically heated; test conditions and results obtained are recorded in Table 7. High approaches to thermodynamic equilibrium are reached, the reaction product consisting essentially of C.sub.8 aromatics, benzene, toluene and higher polyalkyl-aromatics (having more than 8 carbon atoms); non aromatic liquid products, generally derived from the hydrogenation of the aromatic nucleus, were present in negligible amounts, while gaseous products (for instance CH.sub.4) were not revealed by the gaschromatographic analysis. Approach to thermodynamic equilibrium means (% by weight): ##EQU1##
The percentage of para-xylene at equilibrium is calculated in the 3-components system; no ethylbenzene was obtained from the xylenes.
EXAMPLE 8
90 g of (DEPP) Br, 4.5 g of Na aluminate and 15.8 g of NaOH were dissolved in 675 cm.sup.3 of H.sub.2 O. The solution was heated at 60.degree.-70.degree. C., whereupon 330 g of silica sol (Ludox HS) were added, and then heated again at from 60.degree. to 70.degree. C. under intense stirring for 10 minutes. Ludox HS is a colloidal aqueous solution containing 30.5% by weight of SiO.sub.2 and 0.32% Na.sub.2 O as stabilizer; the resulting mixture had the following composition by mols:
______________________________________SiO.sub.2 = 1.678 Na.sub.2 O = 0.242 (DEPP)Br = 0.405Al.sub.2 O.sub.3 = 0.025 H.sub.2 O = 50.3______________________________________
The gel was transferred into the autoclave of example 1 and heated at 190.degree. C. for 4 days in only one step under stirring (30 rpm). After cooling, the suspension was discharged and filtered; the solid was washed and dried as in example 1. The product was crystalline; its composition was (% by weight):
______________________________________Si = 42.6 Na = 0.4 C = 3.4Al = 0.9 H = 0.4 N = 0.4______________________________________
The product revealed the diffraction pattern shown in Table 8. The solid activated as in example 1 exhibited the following vapor adsorption at 25.degree. C.:
______________________________________water = 5.8% b.w.; n-hexane = 4.9% b.w.; cyclohexane = 2.7% b.w.______________________________________
The compound, washed and dried at 120.degree. C., was exchanged with NH.sub.4.sup.+ as in example 2. At the end the compound was washed and dried as in example 2. Its composition (% by weight) was:
______________________________________Si = 42.5 Na = 0.2 C = 3.3Al = 1.1 H = 0.4 N = 0.7______________________________________
By activation as in example 2, the "H-zeolite" was obtained. 35.8 parts by weight of such zeolite in acid form were admixed with 3.6 parts b.w. of bentonite and homogeneously kneaded with a solution obtained by dissolving 2.15 parts b.w. of nickel nitrate (hexahydrate) in 25 parts b.w. of H.sub.2 O; the whole was extruded into granules having a diameter of 1 mm.
The product was dried for 12 hours between 110.degree. and 120.degree. C. and activated for 2 hours at 540.degree. C. 30 cm.sup.3 of the thus obtained catalyst were loaded into the reactor of example 7; test conditions and results are recorded in Table 7.
Zeolites, prepared according to this example and to other examples using DEPP.sup.++ cation, were indicated by us as "MB-28" zeolites. The characterizing molar ratios of starting solutions compositions of examples 1, 3, 5, 8 and 10 are reported in the following table:
__________________________________________________________________________ Ex. ##STR2## ##STR3## SF = r.sub.2 /r.sub.1 ##STR4##__________________________________________________________________________1 150 90 0.60 0.243 150 90 0.60 0.245 175 105 0.60 0.248 248 113 0.46 0.26 10 249 150 0.60 0.22__________________________________________________________________________
It is worthwhile to note that r.sub.1 (organic cation ratio) and r.sub.2 (global cation ratio) of examples 8 and 10 are rather high, with respect to the corresponding ratios of examples 1, 3 and 5; in particular, for the present example 8 the r.sub.2 /r.sub.1 (sodium)factor is lower than for the other examples (<0.5). The CMF (cation mineralization factor) is quite similar for all the examples.
EXAMPLE 9
The "H form" for the zeolite prepared according to example 8 was tested in an apparatus as in example 7 and at the beginning the results were better, but after a few hundreth of hours lower results were obtained, with respect to the nickel impregnated zeolite tested in example 8; it is clear that nickel exerts a beneficial action on the catalyst life.
EXAMPLE 10
50 g of (DEPP)Br and 2 g of Na aluminate were dissolved in 400 cm.sup.3 of H.sub.2 O. The solution was heated at 60.degree.-70.degree. C., whereupon 15 g of an aqueous solution of sodium silicate and 150 g of silica sol (Ludox HS) were added; the silicate solution contained 20% by weight SiO.sub.2 and 23% by weight Na.sub.2 O, which practically corresponds to the formula of metasilicate. We heated again at from 60.degree. to 70.degree. C. under intense stirring for 10 minutes. The solution had the following composition by mols:
______________________________________SiO.sub.2 = 0.813 Na.sub.2 O = 0.075 (DEPP) Br = 0.225Al.sub.2 O.sub.3 = 0.011 H.sub.2 O = 28.1______________________________________
The gel was transferred into the autoclave of example 1 and heated at 170.degree. C. for 7 days, under stirring (30 rpm). After cooling, the suspension was discharged and filtered; the solid was washed and dried as in example 1; its composition was (% by weight):
______________________________________Si = 39.9 Na = 0.5 C = 6.9Al = 1.0 H = 1.1 N = 0.9______________________________________
The solid, activated as in example 1, exhibited the following vapor adsorption at 25.degree. C.;
water=10.1% b.w.; n-hexane=9.5% b.w.; cyclohexane=5.0% b.w.
The compound, washed and dried at 120.degree. C., was exchanged with NH.sub.4.sup.+ as in example 2. At the end the compound was washed and dried as in Example 1. Its composition (% by weight) was:
______________________________________Si = 41.2 Na = 0.2 C = 6.5Al = 1.0 H = 0.8 N = 0.9______________________________________
By activation as in Example 2, the "H-zeolite" was obtained; 30 g of such "H form" of the zeolite were admixed with 3 g of bentonite and homogeneously Kneaded with 25 cm.sup.3 of H.sub.2 O; the whole was then extruded into granules having a diameter of 1 mm. The granules were dried for 12 hours between 110.degree. and 120.degree. C. and activated again for 2 hours at 540.degree. C. 30 cm.sup.3 of catalyst were loaded into the reactor of example 7; test conditions and results are reported on Table 7.
EXAMPLE 11
The catalyst of example 10 was regenerated in air at 540.degree. C. for 16 hours and 15.5 g of the regeneraed granules were impregnated with 18 cm.sup.3 of an aqueous solution containing 0.85 g of Ni(NO.sub.3).sub.2.0.6H.sub.2 O. After drying at 120.degree. C. for 12 hours the granules were loaded in the reactor of example 7 and identical conditions were used as in example 10. The results are reported in Table 7. The best performance, when nickel is present, is reached after many hours, which is an index of stability and long life.
EXAMPLE 12
60 g of (DEPP)Br, 3 g of Na aluminate and 10.5 g of NaOH were dissolved in 450 cm.sup.3 of H.sub.2 O. The solution was heated at 60.degree.-70.degree. C., whereupon 150 g of silica sol (Ludox HS) were added, and then heated again at a temperature from 60.degree. to 70.degree. C. under intense stirring for 10 minutes. The composition by moles was:
______________________________________SiO.sub.2 = 0.763 Na.sub.2 O = 0.157 (DEPP)Br = 0.270Al.sub.2 O.sub.3 = 0.017 H.sub.2 O = 30.8______________________________________
The following molar ratios and factors were used:
r.sub.1 =228; r.sub.2 =105; SF=0.46; CMF=0.37
It is worthwhile to note that CMF (cation mineralization factor) of this example is higher than previous examples.
The gel was transferred into the autoclave of example 1 and heated at 190.degree. C. for 4 days under stirring (30 rpm). After discharge, the solid was washed and dried as in example 1. The product was crystalline and exhibited the X-rays pattern of Table 9; its chemical composition was (% by weight):
______________________________________Si = 40.4 Na = 0.7 C = 4.9Al = 1.3 H < 0.1 N = 0.7______________________________________
After activation as in example 1, the solid exhibited the following vapor adsorption at 25.degree. C.:
______________________________________water = 9.4 b.w.n-hexane = 6.7 b.w. cyclohexane = 4.1 b.w.______________________________________
The compound, washed and dried at 120.degree. C. (but not activated) was exchanged with NH.sub.4.sup.+ (see example 2) and dried at 120.degree. C. for 12 hours. Its composition was:
______________________________________Si = 40.7% b.w. Na = 0.1% b.w. C = 4.9% b.w.Al = 1.5% b.w. H < 0.1% b.w. N = 1.0% b.w.______________________________________
By activation of the compound as in example 2, the "H zeolite" was obtained.
EXAMPLE 13
75 g of (DEPP)Br, 3 g of Na aluminate and 12 g of NaOH were dissolved in 450 cm.sup.3 of H.sub.2 O. The solution was heated at 60.degree.-70.degree. C., whereupon 205 g of silica sol (Ludox HS) were added, and then heated again at a temperature from 60.degree. to 70.degree. C. under intense stirring for 10 minutes. The composition (by moles) was:
______________________________________SiO.sub.2 = 1.042 Na.sub.2 O = 0.179 (DEPP)Br = 0.338Al.sub.2 O.sub.3 = 0.017 H.sub.2 O = 33.0______________________________________
which corresponds to the following ratios and factors:
______________________________________r1 = 195 r2 = 95 SF = 0.49 CMF = 0.32______________________________________
also in this example, the CMF factor is very high.
The gel was transferred into the autoclave of example 1 and heated at 190.degree. C. for 4 days under stirring (30 rpm). After discharge, the solid was washed and dried as in example 1. The product was crystalline and exhibited the X-rays pattern of Table 10; its chemical composition was (% by weight):
______________________________________Si = 42.6 Na = 0.5 C = 4.1Al = 1.0 H = 0.5 N = 0.5______________________________________
After activation as in example 1, the solid exhibited the following vapor adsorption at 25.degree. C.;
______________________________________water = 7.3 b.w.n-hexane = 5.8 b.w. cyclohexane 3.9 b.w.______________________________________
The compound, washed and dried at 120.degree. C. (but not activated) was exchanged with NH.sub.4.sup.+ (see example 2) and dried at 120.degree. C. for 12 hours. Its composition was:
______________________________________Si = 42.1% b.w. Na = 0.2% b.w. C = 3.9% b.w.Al = 1.0% b.w. H = 0.9% b.w. N = 0.7% b.w.______________________________________
By activation of the compound as in example 2, the "H zeolite" was obtained.
EXAMPLE 14
The zeolite in the acid form obtained in examples 12 and 13 were mixed with 10% by weight of bentonite, homogenously kneaded with a suitable amount of H.sub.2 O and extruded in pieces having a diameter of 1 mm; the product was then dried for 12 hours between 110.degree. and 120.degree. C. and for 2 hours at 540.degree. C. The resulting catalyst was used in the isomerization of meta-xylene. 30 cm.sup.3 of catalyst were charged into the reactor of example 7; test conditions and results are recorded in Table 11, where "AEQT para" is the approach to thermodynamic equilibrium, calculated on the basis of the paraxylene amounts and described in example 7. The other two expressions "AEOT meta" and "AEQT ortho" in Table 11 have been obtained by replacing the paraxylene amounts, in the formula of example 7, respectively by the corresponding amounts of metaxylene and orthoxylene.
EXAMPLE 15 (Endurance test)
18.2 parts by weight of the H zeolite of example 12 were mixed with 0.8 parts by b.w. of bentonite and homogeneously kneaded with a solution obtained by dissolving 1.04 parts b.w. of Ni(NO.sub.3).sub.2.6H.sub.2 O in 14 parts b.w. of H.sub.2 O; the whole was then extruded, dried and activated as in example 8 and 30 cm.sup.3 of the catalyst were tested as in example 7. Data and results (after 6, 24, 120 and 240 hours) are reported in Table 11.
__________________________________________________________________________d (A) l/l.sub.o d (A) l/l.sub.o d (A) l/l.sub.o d (A) l/l.sub.o d (A) l/l.sub.o__________________________________________________________________________13.51 13 4.26 18 2.788 1 2.007 11 1.491 111.16 56 4.13 4 2.733 3 1.999 3 1.454 210.02 29 4.08 1 2.703 2 1.982 1 1.436 39.79 3 3.97 52 2.683 1 1.962 1 1.420 29.06 46 3.84 98 2.659 2 1.945 3 1.407 27.45 16 3.83 24 2.607 5 1.916 2 1.396 27.08 8 3.76 11 2.577 2 1.906 3 1.383 46.71 5 3.72 39 2.545 3 1.874 7 1.376 76.55 42 3.65 18 2.508 6 1.820 10 1.374 26.37 9 3.50 1 2.495 3 1.806 2 1.336 <16.06 6 3.46 53 2.458 6 1.787 3 1.288 16.00 13 3.37 8 2.416 4 1.767 1 1.258 35.78 16 3.35 100 2.401 2 1.757 2 1.241 15.73 1 3.24 1 2.283 6 1.720 1 1.230 15.57 14 3.216 30 2.238 3 1.713 2 1.220 <15.42 1 3.195 8 2.216 1 1.690 2 1.212 25.14 6 3.140 3 2.200 1 1.673 5 1.200 35.00 8 3.089 3 2.173 1 1.662 24.85 2 3.053 11 2.131 4 1.641 14.69 2 2.984 12 2.114 1 1.624 14.60 9 2.945 6 2.108 1 1.614 24.51 38 2.924 1 2.080 2 1.591 24.45 1 2.880 13 2.065 1 1.564 24.37 7 2.856 2 2.036 1 1.542 8-- -- -- -- 2.028 5 1.519 3__________________________________________________________________________
TABLE 2__________________________________________________________________________d (A) l/l.sub.o d (A) l/l.sub.o d (A) l/l.sub.o d (A) l/l.sub.o d (A) l/l.sub.o__________________________________________________________________________13.51 13 4.13 1 2.726 1 1.942 2 1.383 311.16 68 4.08 1 2.703 1 1.917 1 1.376 510.02 35 3.96 20 2.683 1 1.904 1 1.374 19.76 3 3.84 48 2.659 1 1.869 3 1.344 19.06 30 3.83 28 2.607 3 1.820 10 1.289 18.14 1 3.75 4 2.545 1 1.784 1 1.254 27.45 1 3.72 23 2.504 4 1.767 1 1.242 17.11 1 3.65 7 2.491 2 1.754 1 1.229 16.69 5 3.51 1 2.458 6 1.714 1 1.226 16.55 19 3.46 22 2.416 2 1.687 1 1.210 26.35 7 3.35 100 2.392 2 1.673 4 1.200 36.00 14 3.27 1 2.279 6 1.658 35.78 6 3.25 1 2.238 2 1.610 15.71 2 3.215 12 2.211 1 1.588 15.57 8 3.195 4 2.200 1 1.562 15.42 1 3.137 1 2.159 1 1.542 75.36 1 3.085 1 2.131 5 1.515 15.14 2 3.048 5 2.108 1 1.487 15.00 7 2.978 8 2.078 <1 1.471 14.84 1 2.945 3 2.067 <1 1.450 24.69 1 2.920 2 2.028 2 1.447 24.60 5 2.880 4 2.007 5 1.433 14.51 13 2.867 1 1.993 5 1.420 24.36 5 2.784 1 1.981 <1 1.396 14.26 22 2.776 1 -- -- -- --__________________________________________________________________________
TABLE 3__________________________________________________________________________d (A) l/l.sub.o d (A) l/l.sub.o d (A) l/l.sub.o d (A) l/l.sub.o d (A) l/l.sub.o__________________________________________________________________________13.51 4 4.13 2 2.703 1 1.962 1 1.420 111.16 38 4.08 1 2.683 1 1.945 2 1.407 110.02 18 3.97 17 2.659 1 1.916 2 1.396 19.79 5 3.83 72 2.607 4 1.910 1 1.383 29.06 18 3.82 24 2.574 1 1.874 4 1.376 27.45 11 3.75 7 2.545 2 1.820 10 1.374 57.08 6 3.72 26 2.508 4 1.806 1 1.336 <16.71 3 3.65 11 2.495 3 1.787 1 1.288 16.55 16 3.50 1 2.458 6 1.767 1 1.257 26.38 6 3.46 20 2.416 2 1.757 1 1.241 <16.06 3 3.37 9 2.401 1 1.720 1 1.232 16.00 10 3.35 100 2.283 6 1.713 1 1.220 <15.78 7 3.24 1 2.238 3 1.690 1 1.212 15.73 1 3.216 8 2.216 1 1.673 4 1.200 25.57 10 3.195 5 2.200 1 1.662 35.42 1 3.142 1 2.173 1 1.641 <15.37 1 3.089 1 2.131 5 1.624 <15.14 4 3.053 6 2.108 1 1.614 15.01 5 2.984 9 2.080 1 1.591 14.85 1 2.945 3 2.070 1 1.564 14.61 6 2.924 1 2.036 1 1.542 74.51 14 2.880 5 2.028 1 1.520 14.45 1 2.856 2 2.007 2 1.489 14.37 5 2.788 1 1.999 7 1.454 34.26 24 2.733 1 1.982 1 1.436 1__________________________________________________________________________
TABLE 4__________________________________________________________________________d (A) l/l.sub.o d (A) l/l.sub.o d (A) l/l.sub.o d (A) l/l.sub.o d (A) l/l.sub.o__________________________________________________________________________13.51 7 3.96 15 2.455 7 1.714 1 1.228 111.16 50 3.84 48 2.416 2 1.689 1 1.225 110.02 29 3.83 21 2.392 2 1.672 5 1.210 19.79 3 3.75 5 2.281 6 1.659 3 1.200 29.06 19 3.71 24 2.259 1 1.625 17.40 1 3.64 8 2.238 2 1.610 17.05 1 3.46 19 2.211 1 1.588 16.69 4 3.35 100 2.200 <1 1.583 16.55 14 3.26 1 2.170 1 1.564 16.35 7 3.215 8 2.126 5 1.541 76.00 12 3.195 4 2.099 1 1.519 15.78 4 3.131 2 2.075 1 1.514 15.72 2 3.085 1 2.067 1 1.488 15.56 8 3.048 6 2.028 2 1.458 15.36 1 2.975 7 2.007 3 1.451 15.14 2 2.936 3 1.992 5 1.445 15.00 5 2.880 4 1.981 1 1.435 14.84 1 2.784 1 1.942 2 1.420 14.72 <1 2.726 1 1.917 1 1.396 14.60 4 2.679 1 1.904 1 1.383 44.51 10 2.655 1 1.869 3 1.372 64.35 5 2.607 3 1.820 10 1.288 14.26 24 2.545 1 1.784 1 1.286 14.12 1 2.504 1 1.768 1 1.256 24.08 1 2.488 3 1.755 1 1.240 1__________________________________________________________________________
TABLE 5__________________________________________________________________________d (A) l/l.sub.o d (A) l/l.sub.o d (A) l/l.sub.o d (A) l/l.sub.o d (A) l/l.sub.o__________________________________________________________________________13.51 4 4.37 2 2.880 4 2.028 `1 1.521 111.16 11 4.26 20 2.856 1 2.007 3 1.492 110.02 6 4.13 1 2.788 <1 1.999 2 1.454 29.79 1 4.08 <1 2.733 <1 1.982 3 1.437 <19.06 10 3.97 10 2.703 <1 1.962 <1 1.420 17.45 3 3.84 29 2.687 1 1.945 1 1.407 17.28 1 3.83 6 2.659 <1 1.916 1 1.395 17.08 2 3.75 1 2.607 1 1.910 1 1.383 46.71 1 3.72 9 2.577 <1 1.874 1 1.376 26.55 8 3.65 3 2.545 1 1.820 10 1.375 66.38 2 3.56 <1 2.508 2 1.802 3 1.336 26.06 1 3.50 <1 2.495 1 1.787 1 1.290 26.00 3 3.46 18 2.458 7 1.767 1 1.258 25.78 4 3.37 4 2.416 1 1.757 1 1.241 <15.73 1 3.35 100 2.401 <1 1.726 2 1.230 15.57 4 3.27 <1 2.283 7 1.713 <1 1.220 15.42 <1 3.24 <1 2.238 3 1.690 <1 1.212 <15.37 1 3.216 6 2.216 1 1.673 4 1.201 25.14 2 3.195 2 2.173 <1 1.662 25.00 2 3.140 1 2.131 4 1.641 <14.85 1 3.089 <1 2.114 8 1.624 <14.69 1 3.053 2 2.108 <1 1.614 14.60 2 2.984 14 2.080 <1 1.591 14.51 8 2.945 1 2.070 <1 1.563 14.45 <1 2.921 <1 2.036 1 1.543 7__________________________________________________________________________
TABLE 6__________________________________________________________________________d (A) ll/l.sub.o d (A) l/l.sub.o d (A) l/l.sub.o d (A) l/l.sub.o d (A) l/l.sub.o__________________________________________________________________________13.51 3 4.10 <1 2.729 1 1.994 2 1.462 111.16 19 4.06 <1 2.700 1 1.982 3 1.454 210.02 11 3.97 8 2.659 <1 1.963 <1 1.436 <19.77 2 3.85 18 2.607 1 1.945 1 1.420 19.05 9 3.83 9 2.577 <1 1.922 <1 1.406 <17.45 1 3.75 1 2.545 1 1.910 1 1.396 17.32 <1 3.72 9 2.503 2 1.871 2 1.383 37.08 <1 3.65 3 2.491 1 1.840 <1 1.376 26.70 1 3.56 <1 2.458 6 1.820 11 1.375 66.55 7 3.50 <1 2.416 1 1.787 1 1.290 16.35 2 3.46 11 2.401 1 1.767 <1 1.257 25.99 5 3.39 2 2.342 <1 1.758 <1 1.243 <15.78 3 3.35 100 2.327 <1 1.748 <1 1.229 15.73 1 3.27 <1 2.283 6 1.727 <1 1.211 15.57 3 3.24 1 2.238 3 1.714 <1 1.201 25.37 <1 3.216 6 2.216 <1 1.690 <15.14 1 3.198 1 2.173 <1 1.673 35.00 2 3.141 1 2.131 5 1.662 24.84 <1 3.089 1 2.106 <1 1.641 <14.69 <1 3.051 2 2.080 <1 1.623 <14.59 1 2.981 3 2.065 <1 1.613 14.51 6 2.945 1 2.036 <1 1.591 <14.36 2 2.917 <1 2.028 1 1.543 74.26 20 2.880 3 2.007 2 1.519 14.13 <1 2.788 <1 -- -- -- --__________________________________________________________________________
TABLE 7 (*)__________________________________________________________________________ Feeding % by weight of products (**) % by weight Operative Conversion or- ethyl- conditions Ap- Loss ethyl- para- tho- ethyl- higher melaxi- ben- LHSV Temp. proach C.sub.8 arom. benzene meta- xy- xy- ben- ben- tolu- aro-Catalyst lene zene (h.sup.-1) .degree.C. equilib. % b.w. % b.w. xylene lene lene zene zene ene matics__________________________________________________________________________Ex. 2 89.1 10.9 2.0 300 89.0 2.7 15.2 57.0 18.7 12.2 9.4 0.8 1.1 0.8Ex. 2 89.1 10.9 2.0 325 89.8 4.0 20.4 56.6 19.0 13.1 8.3 1.4 1.2 0.4Ex. 2 89.1 10.9 4.2 350 90.9 5.4 39.9 54.4 18.9 14.4 7.0 2.1 1.5 1.7Ex. 2 89.1 10.9 4.1 375 91.8 7.6 49.7 52.6 18.8 15.5 5.6 3.0 2.2 2.3Ex. 2 89.1 10.9 2.1 375 92.8 12.1 68.6 48.8 18.4 16.9 3.8 4.1 3.9 4.1Ex. 4 90.6 9.4 2.1 300 83.9 1.5 17.8 62.3 18.1 9.8 8.3 0.7 0.6 0.2Ex. 4 90.6 9.4 2.0 325 88.2 2.3 25.6 59.1 19.0 12.6 7.0 1.3 0.7 0.3Ex. 4 90.6 9.4 3.8 350 91.1 3.5 34.3 56.9 19.5 14.0 6.2 1.7 0.9 0.8Ex. 4 90.6 9.4 2.0 350 92.9 5.8 51.6 52.8 19.7 16.9 4.9 2.6 1.8 1.3Ex. 4 90.6 9.4 6.0 375 92.3 5.1 44.6 54.8 19.5 15.2 5.0 2.6 1.7 1.2Ex. 6 100 -- 2.0 300 91.7 1.1 / 64.6 21.7 12.6 0 0 0.6 0.5Ex. 6 100 -- 2.0 325 96.5 2.7 / 57.9 22.4 17.1 0 <0.1 1.3 1.3Ex. 6 100 -- 4.0 350 96.6 3.8 / 56.2 22.2 17.9 0 <0.1 1.9 1.8Ex. 6 100 -- 6.0 375 95.8 5.4 / 54.8 21.6 18.2 0 0.1 2.6 2.7Ex. 6 100 -- 4.0 375 97.0 6.2 / 52.7 21.6 19.4 0 0.1 3.1 3.1(***)Ex. 8 100 -- 6.0 350 100.0 2.2 / 55.6 23.2 19.1 0 <0.1 1.3 0.8Ex. 10 100 -- 6.0 325 97.5 0.6 / 53.7 23.1 22.6 0 0 0.4 0.2(****)Ex. 11after 24 hrs 100 -- 5.0 325 99.3 2.9 / 52.7 23.0 21.5 0 <0.1 1.5 1.3after 360 hrs 100 -- 5.0 325 99.5 1.1 / 53.9 23.4 21.5 0 0 0.7 0.5__________________________________________________________________________ (*) All the tests were carried out at 15 atm. and with H.sub.2 O/hydrocarbon molar ratios = 5; data were determined after 2 hours (**) Nonaromatic liquid products: 0.1%; gaseous products (***) Hzeolite extruded with 10% bentonite and then impregnated with 1.1% Nickel before use, in order to reach a longer (****) Hzeolite mixed with 10% b.w. of bentonite and 1.1% Nickel and then extruded
TABLE 8______________________________________d (A) l/l.sub.o d (A) l/l.sub.o d (A) l/l.sub.o______________________________________13.51 3 3.216 3 1.874 111.16 13 3.192 3 1.820 1110.01 7 3.140 1 1.802 19.79 2 3.099 1 1.787 19.05 4 3.053 2 1.768 17.45 3 2.980 4 1.757 17.07 2 2.947 1 1.713 16.71 1 2.921 1 1.694 16.55 3 2.880 1 1.673 46.38 3 2.856 1 1.662 26.05 2 2.788 1 1.622 15.99 3 2.729 1 1.614 15.78 1 2.703 1 1.591 15.71 2 2.687 1 1.565 15.57 4 2.656 1 1.543 75.42 1 2.607 1 1.521 15.37 1 2.573 1 1.491 15.14 1 2.545 1 1.454 25.00 2 2.508 1 1.420 14.85 1 2.491 1 1.408 14.60 2 2.458 7 1.395 14.51 3 2.416 1 1.383 54.45 1 2.397 1 1.376 24.36 2 2.283 7 1.375 64.26 22 2.238 3 1.335 14.13 1 2.202 1 1.290 14.08 1 2.170 1 1.258 23.97 5 2.131 5 1.241 13.84 30 2.114 1 1.230 13.83 5 2.094 1 1.217 13.75 4 2.075 1 1.211 13.72 8 2.070 1 1.201 23.65 6 2.040 13.50 1 2.007 23.46 6 1.995 33.37 2 1.982 43.35 100 1.947 13.27 1 1.917 13.24 1 1.912 1______________________________________
TABLE 9__________________________________________________________________________d (A) l/l.sub.o d/(A) l/l.sub.o d (A) l/l.sub.o d (A) l/l.sub.o d (A) l/l.sub.o__________________________________________________________________________13.51 3 4.12 1 2.656 1 1.912 2 1.363 111.16 43 4.08 1 2.607 4 1.874 4 1.288 210.01 25 3.97 10 2.573 2 1.843 1 1.258 29.79 2 3.84 88 2.549 2 1.820 11 1.241 18.98 11 3.83 22 2.508 5 1.769 1 1.230 17.44 13 3.75 8 2.491 2 1.758 1 1.211 17.07 6 3.72 23 2.458 6 1.713 16.71 3 3.65 15 2.415 3 1.694 16.55 6 3.46 15 2.397 2 1.671 56.38 9 3.37 6 2.281 6 1.661 36.05 2 3.34 100 2.238 3 1.614 15.99 11 3.24 1 2.202 <1 1.565 15.76 2 3.216 5 2.170 <1 1.543 65.71 6 3.192 5 2.127 4 1.521 15.57 11 3.140 2 2.114 2 1.497 15.37 1 3.052 9 2.076 2 1.489 15.14 5 2.980 11 2.067 2 1.454 35.00 5 2.947 4 2.032 2 1.420 24.60 6 2.880 3 2.007 2 1.411 14.50 9 2.856 1 1.995 10 1.396 14.36 6 2.788 1 1.982 2 1.384 44.26 23 2.726 2 1.947 2 1.377 3 1.917 1 1.373 5__________________________________________________________________________
TABLE 10______________________________________d (A) l/l.sub.o d (A) l/l.sub.o d (A) l/l.sub.o d (A) l/l.sub.o______________________________________13.51 3 4.08 1 2.508 2 1.661 211.16 20 3.97 7 2.491 2 1.614 110.01 10 3.84 40 2.458 7 1.565 19.79 2 3.82 10 3.415 1 1.543 88.98 6 3.75 3 2.397 1 1.521 17.44 5 3.72 13 2.282 7 1.489 17.07 3 3.65 8 2.238 3 1.454 26.71 2 3.46 9 2.131 6 1.420 16.55 5 3.34 100 2.110 1 1.408 <16.38 5 3.24 1 2.076 <1 1.396 16.05 2 3.216 3 2.067 1 1.384 45.99 4 3.192 2 2.032 1 1.377 75.78 1 3.140 1 2.007 2 1.374 25.71 3 3.053 4 1.995 4 1.290 25.57 5 2.980 5 1.982 2 1.258 25.37 1 2.947 2 1.947 1 1.230 15.14 2 2.880 2 1.917 1 1.201 25.00 2 2.856 <1 1.912 14.85 1 2.788 1 1.874 24.60 3 2.726 1 1.843 14.51 5 2.656 1 1.820 134.36 3 2.607 2 1.805 <14.26 26 2.573 1 1.787 14.13 1 2.549 1 1.758 1 1.713 1 1.673 4______________________________________
TABLE 11.sup.( *.sup.)__________________________________________________________________________ OPERATIVE CON- DITIONS.sup.( **.sup.) AEQT Loss % BY WEIGHT OF PRODUCTS.sup.( ***.sup.) LHSV T meta para ortho C.sub.8 arom. metha- para- ortho- ethyl- higherCATALYST (h.sup.-1) (.degree.C.) % b.w. % b.w. % b.w. % b.w. xylene xylene xylene benzene benzene toluene aromatics__________________________________________________________________________Ex. 12 6 300 96.5 99.4 93.5 0.6 54.9 23.6 20.9 0.0 0.0 0.1 0.5Ex. 12 6 325 97.9 99.4 96.1 3.2 52.5 22.9 21.4 0.0 <0.1 1.8 1.4Ex. 12 6 350 98.1 99.4 96.7 7.7 49.8 21.7 20.8 0.0 0.1 4.4 3.2Ex. 12 6 375 98.0 99.6 96.3 14.1 46.1 20.2 19.6 0.0 0.4 8.0 5.7Ex. 13 6 300 88.3 98.8 77.1 0.6 58.6 23.5 17.3 0.0 0.0 0.3 0.3Ex. 13 6 325 95.1 99.6 90.3 1.5 54.8 23.4 20.4 0.0 <0.1 0.8 0.6Ex. 13 6 350 96.9 99.6 94.2 3.2 52.7 22.8 21.3 0.0 <0.1 1.9 1.3Ex. 13 6 375 97.6 99.7 95.4 6.5 50.3 22.0 21.2 0.0 0.1 3.7 2.7Ex. 12.sup.( ****.sup.)after 6 hrs 6 300 94.9 99.3 90.2 2.6 54.5 23.1 19.8 -- -- 1.4 1.1after 24 hrs 6 300 95.1 99.1 90.7 3.0 54.2 23.0 19.8 -- -- 2.1 0.9after 120 hrs 6 300 95.6 99.3 91.7 1.5 54.8 23.4 20.3 -- -- 0.9 0.6after 240 hrs 6 300 95.7 100.0 90.8 1.2 54.9 23.7 20.2 -- -- 0.7 0.5__________________________________________________________________________ .sup.(*.sup.) The feed contained 99.80% metaxylene, 0.16% orthoxylene and 0.04 paraxylene? .sup.(**.sup.) All the tests were carried out at 15 atm. with H.sub.2 : hydrocarbon molar ratios = 5; the data were determined after a 2 hours .sup.(***.sup.) Non-aromatic liquid product: 0.1; gaseous products: .sup.(****.sup.) H--zeolite mixed with 10% b.w. of bentonite and 1.1% Ni and then extruded

Number	Name	Date
3702886	Argauer et al.	Nov 1972
4000248	Martin	Dec 1976
4205053	Rollmann et al.	May 1980
4251499	Nanne et al.	Feb 1981

Method for preparing zeolites

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CPC

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