GB1601250A - Aluminosilicate powders and sols - Google Patents

Description

(54) ALUMINOSILICATE POWDERS AND SOLS (71) We, E.I. DU PONT DE NEMOURS AND COMPANY, a corporation organized and existing under the laws of the State of Delaware, located at Wilmington, State of Delaware, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention concerns porous amorphous aluminosilicate powders having uniform pore sizes which may be used as catalysts.

Our Application 36574/77 Serial No. 1587236 describes and claims an amorphous aluminosilicate powder comprising aggregates of spheroidal particles which are 3 to 90 nanometers in diameter and have a uniformity such that the maximum standard deviation of the particles is 0.37d where d is the weight average particle diameter; which particles comprise a core of silica, aluminosilicate or one or more refractory metal oxides, and a coating of at least 0.5 nanometers in depth around said core of an amorphous hydrous aluminosilicate compound having a molar ratio of Si:Al of from 1:1 to 19:1, which core and coating may be integral when formed of the same material; the powder having a specific surface area of 30 to 750 m2/g, a bulk density of 0.5 g/cc or more and a uniform median pore diameter between the spheroidal particles in the range of 20 to 1500A, said uniformity being such that 90% or more of the pore volume is of pores of from 0.6D to 1.41D in size, where D is the median pore diameter.

Our earlier application 36574/77 Serial No. 1587236 also describes and claims a process for the preparation of such powders, which comprises separately and simultaneously adding solutions of (a) sodium or potassium silicate (containing 1 to 36g of silica per 100 cc) or silicic acid (containing 1 to 12% by weight silica) and (b) sodium or potassium aluminate (containing 1 to 15% by weight alumina) to a heel sol of discrete colloidal aluminosilicate, silica or refractory oxide particles of uniform or substantially uniform size within the range 2 to 87 nanometers, said feed solutions being added in relative rates and proportions to maintain a constant or substantially constant molar ratio of Si:Al in the feed streams of from 1:1 to 19:1 with the rate of addition of silica not exceeding 10g of SiO2 per 1,000 square meters of total surface area of the particles in the heel sol per hour, and the pH of the heel being maintained at a constant pH between 9 and 12 during the additions of (a) and (b) until the desired particle size is reached; and further comprises drying to a powder at a rate at which no gelling will occur.

The aluminosilicate powders described in our Application 36574/77 Serial No. 1587236 are useful as catalysts, particularly in petroleum refining and catalyst cracking processes, and the uniformity of their pore size is an important factor in their effectiveness in this respect.

We have now found that aluminosilicate powders similar to those described in our earlier application but having a different pore size uniformity and/or different pore diameters are also useful as catalysts.

The invention thus provides an amorphous aluminosilicate powder as defined in any one of claims 1 to 14 of Application 36574/77 Serial No. 1587236 but having a uniform median pore diameter between the spheroidal particles in the range 45 to 250to, with pore diameters of 45 to 150A having a uniformity such that 80 to 90% of the pore volume is of pores of from 0.6D to 1.4D in size, where D is the median pore diameter, and with pore diameters of 150 to 250A having a uniformity such that at least 80% of the pore volume is of pores of from 0.6D to 1.4D in size.

In all respects other than those just mentioned the powders of this invention are as described in our Application 36574/77 Serial No. 1587236. Thus the chemical nature, the physical properties and the structure of the powders are otherwise the same as described in detail in our earlier application.

The powders of the invention may be prepared by the same methods as described in Application 36574/77 Serial No. 1587236, and in this respect it will be appreciated that the differences in pore diameter and pore size uniformity between the powders of the invention and those of our earlier application materialise in the drying step. The powders may be analysed and their properties measured to confirm that they have the requisite characteristics by the methods described in our earlier application, and they may be used as catalysts in the same way as described in that application.

Thus it has been found that aluminosilicate porous powders with uniform pore size distribution comprising spheroidal colloidal particles of uniform size can be prepared by first growing uniform size particles at a constant pH to prepare a uniform particle size amorphous aluminosilicate sol and then drying said uniform particle size sol to a powder without gelling the sol.

The compositions of this invention, which are particularly useful as a catalyst, consist essentially of uniformly porous powders comprising spheroidal colloidal particles of uniform size packed into porous aggregates having a uniform pore diameter between the particles, a bulk density of 0.5 glcc or more, preferably from 0.5 to 0.9 g/cc and a specific surface area of 30 to 750 m2/g of said particles having a surface of amorphous aluminosilicate.

The uniform spheroidal discrete colloidal particles of the sol to be dried have particle diameters which range from 3 to 90 nanometers.

The spheroidal particles have a coating that consists of an amorphous aluminosilicate.

Said aluminosilicate is coated or deposited on a pre-formed core of more or less spheroidal colloidal particles which may or may not have the same composition as the deposited aluminosilicate. For catalytic activity it is only essential that the required colliodal particles have a coating or surface of catalytically active amorphous aluminosilicate. This coating composition extends within the surface to a depth of at least 0.5 nanometer, preferably 0.5 to 1.5 nanometers. Although this composition can extend to a depth of greater than 1.5 nanometers, depths greater than 1.5 nanometers are seldom required.

Thus, in accordance with the invention, the porous powder composition may comprise porous aggregates of spheroidal particles which are 3 to 90 nanometers in size and nonporous to nitrogen and contain: (a) a core silica, aluminosilicate or one or more refractory metal oxides selected from alumina, zirconia, titania, thoria and rare earth oxides; (b) a coating around said core of at least 0.5 nanometer in depth of an amorphous hydrous aluminosilicate compound having a molar ratio of Si:Al of from 1:1 to 19:1 and comprising one or more cations selected from sodium, potassium, ammonium, hydrogen and Groups I to VIII metals selected from Cs, Li, Mg, Ca, Sr, Ba, Sc, Ti, V Cr, Mn, Fe, Co, Ni, Cu, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, La, Ce, rare earthmetals, Hf, Ta, W, Re, Os, Ir, Pt, Au, Sn, Cd, Bi and Sb; and (c) a surface layer over said coating of 0 to 15% by weight of a metal or metal oxide selected from Cs, Li, Mg, Ca, Sr, Ba, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, La, Ce, rare earth metals, Hf, Ta, W, Re, Os, Ir, Pt, Au, Sn, Cd, Bi and Sb; said powder composition having a specific surface area of 30 to 750 m2/g, a bulk density of 0.5 glcc or more and substantially uniform size pore diameters as defined above.

The aluminosilicates of this invention are prepared by a process comprising: (a) preparing a heel sol of discrete colloidal particles selected from sodium, potassium or ammonium aluminosilicate, silica and one or more refractory metal oxides selected from the group consisting of titania, alumina, zirconia, lanthana, thoria and rare earth metal oxides, said heel sol comprising particles of a substantially uniform diameter within the range of 2 to about 85 nanometers, the initial concentration in the heel sol of sodium, potassium, ammonium aluminosilicate or total refractory metal oxide being at least 0.2% by weight with the particles stabilized against aggregation in the pH range 9 to 12; (b) adding to said heel, separately but simultaneously, two feed solutions, one being a solution of sodium or potassium silicate having from 1 to 36 grams of silica per 100 cc, or a sol of silicic acid containing from 1 to 12% silica, the other being a solution of sodium or potassium aluminate containing from 1 to 15% alumina, said feed solutions being added in relative rates and proportions to maintain a constant molar ratio of Si:Al in the feed streams of from 1:1 to 19:1 with the rate of addition of silica not to exceed 10 grams of SiO2 per 1000 square meters of total surface area of particles in the heel sol per hour; (c) maintaining the pH of the heel sol at a constant value between 9 and 12 by adding a cation exchange resin in the hydrogen or ammonium form until the particles in the heel sol have attained an increase in diameter of at least 1 nanometer and a maximum size of 90 nanometers; (d) filtering the sol from (c) to remove the cation exchange resin and optionally adjusting the concentration of the resulting aluminosilicate sol to a solids content of up to 60% by weight; and (e) drying the resulting substantially gel-free sol of particles having an aluminosilicate surface to a powder by removing water at a rate at which no gelling will occur.

Accordingly, the uniform size amorphous aluminosilicate particle sols of this invention are produced by steps a, b and c of the aforesaid process followed by removal of the exchange resin. The uniformity of said particles is such that the maximum standard deviation of the particle size is 0.37d where d is weight average particle size diameter.

Thus, the amorphous aluminosilicate sols of this invention have uniform particles of from 3 to 90 nanometers in diameter with a molar ratio of Si/Al of 1:1 to 19:1, said uniformity defined by particles having a maximum standard deviation of 0.37d, where d is the weighted average particle size diameter.

In the process of making the sol of this invention, the silica reacting with the aluminate ions is either largely monomeric or polymeric. When the silica is monomeric, most of the individual silicon atoms become associated directly with the Alto2 ions forming SiAlO4 ions in the colloidal particles, accompanied in the colloidal particle by the alkali ion present in the reaction such as Na+. On the other hand, in conventional gel processes, substantially more of the silica is polymerised before it can be linked to alumina, therefore less silica units are directly associated with alumina. For these reasons the aluminosilicate compositions of this invention are believed to have a more uniform SiO2 to AlO2 distribution than the conventional silica-alumina gels. This kind of uniformity at a submicron range scale combined with narrow pore size distribution is of great importance in determining the performance of this composition as catalysts and catalyst supports, for example when mixed with active zeolite catalysts.

The powders of this invention have substantially uniform pore sizes because the particles in the aluminosilicate sol before drying are substantially uniform in diameter. The uniform particle size of the sol results because the two individual species, the aluminate ions and silica or silicate ions, are not allowed to react to form new particles or precipitate. The aluminate ions and silica or silicate ions are converted to soluble forms of alumina and silica or silicate which are deposited on the substantially uniform sized nuclei or initial particles in the heel. When the alkaline solutions of silicate and ahlminate are added, the pH of the mixture, but for the addition of ion exchange resin, would rise. The addition of ion exchange resin is regulated to maintain the pH constant in the range of 9 to 12. This control of pH and the maximum addition rate of silicate and aluminate described hereinafter (10 g of SiO2 per 1000 sq. meters of surface area per hour) results in the aluminosilicate particles being of the uniformity described herein.

The refractory oxide sols must be so constituted that the particles remain nonaggregated in a pH range wider than that at which the aluminosilicate is deposited, namely 9 to 12.

Many refractory oxides including alumina, zirconia and thoria are stable by virtue of a positive charge on the particles with nitrate or chloride counter-ions at a pH below 5 or 6.

Ordinarily, when the pH of such a sol is raised to 7 or 8 or higher, the particles coagulate or gel.

In the process of the present invention what is meant by constant pH is maintaining the pH within 1 0.2. The addition of a cation exchange resin in the hydrogen or ammonium form removes sodium ions and prevents the accumulation of sodium salt in the reaction medium that would cause coagulation of the colloidal particles.

The nuclei or particles in the heel are caused to grow into a uniform particle size by the simultaneous but separate addition of a silica sol or a sodium or potassium silicate and sodium or potassium aluminate into a heel in the presence of a cationic exchange resin in the hydrogen or ammonium form for pH control. The nuclei or particles in the heel grow by an accretion process. The cationic exchange resin in the hydrogen or ammonium form may be added to the heel prior to the simultaneous but separate addition of the silica sol or the silicate and aluminate solutions, or it may be added at the time the addition starts or shortly thereafter. Thereafter said resin is added to maintain a constant pH + 0.2.

The aluminosilicate sols of this invention are made up of uniform particles of aluminosilicate having a uniformity such that the maximum standard deviation is 0.37d where d is the weight average particle diameter. The aforesaid sols are especially useful when the maximum standard deviation is 0.30d. The uniformity of the particles in the sols of this invention can also be expressed in a form based on the number average of particles rather than weight average. The uniformity based on particle number average is a maximum standard deviation of 0.43d where d is the number average particle diameter.

The particle size and particle size distribution of the colloidal particles of the aquasol can be determined by photomicroscopic counting techniques involving micrographs obtained with the electron microscope by transmission or scanning electron micrography. The electron micrographs show that the ultimate particles of the sol are essentially discrete or unaggregated. The micrograph is used to determine the particle size and particle size distribution of the colloidal particles of the aquasol by employing a photomicroscopic counting technique utilising a Zeiss Particle Size Analiser TGZ3 to assist in the counting.

The technique is described in the literature as, for example, "Semiautomatic Particle Size Analysis", Ceramic Age, December, 1967, and "Applications of Photomicroscopic Technique to the Particle Analysis of a Sample from a Nuclear Cratering Cloud", by G. F.

Rynders, IMS Proceedings, 313 (1969).

The amorphous aluminosilicate powders of this invention are effective catalysts. Their uniform pore openings permit them to discriminate on the basis of size and configuration of molecules in a system. For example, the narrow pore size distribution of the powders of this invention enable them to be more effective catalysts in petroleum refining and catalyst cracking processes by their improved selectivity. The narrow pore size distribution of the powder permits the selection of a pore size for the catalytic operations without the accompanying of widely varying selectivity based on wide pore size ranges. Thus, the powders of this invention give an optimum catalyst selectivity in cat cracking operations whereby the desired isomers are obtained through narrow control of the pore size.

The compositions of this invention are amorphous aluminosilicates. Crystalline aluminosilicate zeolites are known to possess among other properties catalytic activity. However, crystalline aluminosilicate zeolites are so highly active as catalysts that, when used in the pure state, commercial catalytic cracking units cannot easily control the reaction involved to give desirable results. The present trend in the petroleum industry with regard to such zeolites favors the use of Y-type synthetic faujasite crystalline zeolites of silica/alumina ratios of 4.5 to 5.5/1 because they are thermally and hydrothermally more stable than X-type synthetic faujasite crystalline zeolites of silica/alumina ratios of 2.5/1.

The powders of this invention can be used together with crystalline aluminosilicate zeolites. The uniform distribution of crystalline zeolites within said powders as a matrix substantially improves the performance of the zeolites in catalytic cracking by diluting the active zeolite and moderating its activity while taking advantage of the benefits of the powders of this invention. The amorphous aluminosilicates of this invention are specially suited for this purpose because (1) they provide a matrix catalytically active itself (instead of inactive), (2) they provide access of reactants to the zeolite crystals through pores of controlled size and controlled size distribution and therefore controlled selectivity, (3) they are stable to the high temperature hydrothermal treatment received in commercial regenerators, and (4) they form aggregates or grains hard enough to survive interparticle and reactor wall collisions without excessive breakage or attrition. However, the use of the amorphous aluminosilicates as a matrix and co-catalyst is not limited to one type of crystalline zeolite. The choice of crystalline zeolite to be incorporated in the amorphous aluminosilicate of this invention is based on the type of reaction involved and the type of reactor unit available.

Another advantage of the amorphous aluminosilicates as matrices or co-catalysts with crystalline zeolites is that preferred ions, as for example the mixed rare earth ions in the case of catalytic cracking catalysts, can be uniformly and intimately distributed in the matrix by ion exchange techniques described herein for the parent amorphous aluminosilicate aquasol or the powder obtained by drying the aquasol.

The crystalline aluminosilicate zeolites are well known in the art and described in detail, for example, in Donald W. Breck's book on "Zeolite Molecular Sieves", Wiley Interscience, New York, 1974.

Compositions involving known crystalline aluminosilicate zeolites and the amorphous aluminosilicates of this invention can be made by using the mixing, compounding, etc., techniques disclosed in the art to make zeolite-amorphous aluminosilicate catalysts see for example, "Preparation and Performance of Zeolite Cracking Catalysts", by J. J. Magee and J. J. Blazek, Chapter 11 of ACS Monograph 171, "Zeolite Chemistry and Catalysis", edited by J. A. Rabo, ACS, Wash. D.C. 1976) or by other techniques specially suited to the characteristic properties of our compositions. For example, one way of intimately and uniformly distributing crystalline aluminosilicate zeolite crystals in the amorphous aluminosilicate matrix is to disperse the zeolite crystals of microscopic size in the amorphous aluminosilicate aquasols of the present invention, followed by drying of the aqueous dispersion in the manner described herein.

The amount of crystalline aluminosilicate zeolite that is advantageously incorporated in the amorphous silicate powders of this invention generally is from 5 to 50% by weight.

Thus, catalyst cracking compositions can consist of 5 to 50% by weight (preferably 10 to 25%) of crystalline aluminosilicate zeolites and 95 to 50% by weight (preferably 90 to 75%) of the amorphous aluminosilicates of this invention.

The following examples further illustrate the compositions of this invention and the methods for their preparation. In the examples that follow, all parts are by weight unless otherwise noted. The composition and properties of the powders produced in the Examples were in accordance with the general definition given above.

Example 1 This was an example of the preparation of a hydrous amorphous aluminosilicate powder of the invention where a heel of sodium aluminosilicate was used as the core for the particles making up the powder.

A heel was made by diluting 1166 ml of the aquasol product of Example 3 of Application 36574/77 Serial No. 1587236 (specific surface area 135 m2/g) in the Na form (pH 10.4) containing 10.72% solids, with hot water to complete a total volume of 3 liters. Thus the heel was 4.16% solids and contained 125 g of sodium aluminosilicate. The heel was heated to 1000C and the pH was measured (pH 10). When the heel reached 100"C, the feed solutions of Example 1 of Application 36574/77 Serial No. 1587236 were added each at a rate of 12 ml/min in the manner described in that Example 1 while keeping the temperature of the heel at 1000C + 1"C and the pH at 10.4 + 0.1. The pH was kept constant by periodically adding IRC-84-S ion exchange resin. A total of 3980 ml of each of the feed solutions and 1360 g of resin were used. The build-up ratio (BR) for this first build-up step was therefore 8.96. Build-up ratio is calculated by dividing the total amount of solids in the feed solutions added during the process by the amount of solids present in the heel before starting the addition.

The build-up ratio calculated above and the Sj (specific surface area initially) determined independently by measurement were used to calculate the final specific surface area (SF) with the following formula:

Using the formula d 6000 d DxS where d is the diameter of the particles in nanometers where D is the density of the particles g/cc where S is the specific surface area in m2/g of the particles.

The diameter of the final particles was calculated as follows: 6000 d - 2.2x65 = 42 nanometers.

At the end of the addition the slurry was filtered first through cloth and then through filter paper to separate the ion exchange resin from the aquasol.

The volume of the product recovered was 9700 ml. The concentration was 11.76 g solids per 100 ml. This concentration was determined by evaporating a weighed sample to dryness, calcining the residue and reweighing.

Chemical analysis of the sol gave the following results: 10.5 g SiO2/100 ml, 1.64 g AlO2/100 ml and 0.854 g Na/100 ml. A sample was dried on steam and the specific surface area as measured by the Flow Method of nitrogen adsorption was 70 m2/g. An electron micrograph of the sol showed discrete, dense spherical particles with a uniform particle size distribution, a weight average diameter of 38 nanometers and a number average diameter of 36 nanometers. Standard deviation in both cases was 5 nanometers.

Because of limitations in the size of the vessel and the feed concentration, the above particle build up was continued in a second step. Based on an initial surface area of 70 m2/g, it was calculated that a build-up ratio (BR) of about 5 would be needed to attain a specific surface area of about 40 m2/g. The particle size calculated from SF = 40 was 65 nanometers.

A heel for the second step of the build up was prepared by diluting 850 ml of the sol of concentration 11.76 g solids/100 ml just described with hot tap water to a total volume of 5 liters. The heel was therefore 2% solids and contained a total of 100 g of sodium aluminosilicate.

The heel was heated to 100"C and feed solutions were added each at a rate of 6 ml/min while keeping the pH constant at 10.3 + 0.2 with the periodic addition of ion exchange resin IRC-84-S. The two feed solutions were the same used in the first build-up step, aqueous silicate solution 20 g SiO2/100 ml and aqueous aluminate solution 5 g NaAlO2/100 ml.

A total of 1640 ml of each of the feed solutions and 560 g of ion exchange resin were used.

At the end of the addition, the slurry was filtered first through cloth and then through filter paper to separate the ion exchange resin from the aquasol.

The volume of the product recovered was 7600 ml. Analysis of the product gave the following results: Concentration = 6.96 g solids/100 ml SiO2 = 5.31 g/100 ml AlO2 = 0.87 g/100 ml Na = 0.466 g/100 ml Specific Surface Area = 46 m2/g.

An electron micrograph of the sol showed discrete, dense spherical particles with a uniform particle size distribution, a weight average diameter of 65 nanometers (standard deviation = 5 nanometers) and a number average diameter of 64 nanometers (standard deviation = 6 nanometers).

The sodium aluminosilicate aquasol was converted to the ammonium form by passing it through an ion exchange column packed with wet Dowex 50W-X8 ion exchange resin (DOWEX is a Registered Trade Mark) in the NH4+ form. pH of the NH4+ sol thus formed was 9.5.

The sol was vacuum drum dried under conditions given in Example 3 of Application 36574/77 Serial No. 1587236 and the dry power obtained was analyzed for pore size distribution and pore volume by nitrogen adsorption-desorption as described in Example 1 of that application. The results obtained are as follows: Experimental average pore diameter = 150 Pore Volume = 0.306 ml/g.

The powder had a narrow pore size distribution: both the upper (229 ) and the lower limit (110 ) of pore size for approximately 90% (87%) of the pore volume were within 40% of the median pore diameter (180 A).

Example 2 The powder of Example 1 was tested for its ability to catalyze the synthesis of methylamines. A continuous flow reactor was used in which NH3 and methanol were pumped continuously through a 1" tube containing 50 g of powder. Feed rate used for liquid methanol was 1.50 cc/min, feed rate for ammonia gas, 1100 cc/min. The tube was kept at a constant temperature of 450"C and at a constant pressure of 1 atm. The exit and inlet streams of the tube were analyzed with a gas chromatograph and the yields of methylamines and the conversion of methanol determined.

The operation was repeated using commercial Davison silica-alumina gel Grade 970, a trademark of the Davison Chemical Division of W. R. Grace & Co., with about the same alumina content of our sample. The results obtained with both catalysts are as follows: Composition Davison's of this Invention Grade 970 Methanol conversion, percent 97 90 Dimethylamine yield* 12 8 Monomethylamine yield 14 11 Trimethylamine yield 20 19 *Moles of DMA over moles of methanol converted Thus, the results show that a composition of this invention gave higher methanol conversion, higher desirable monomethylamine production and more favorable product distribution than standard commercial silica-alumina gel.

Example 3 This was an example of the preparation of a hydrous amorphous aluminosilicate powder of the invention where a heel of silica sol prepared in situ was used in the apparatus described in Example 1 of Application 36574/77 Serial No. 1587236 to form the core of the particles of this invention.

A 1% silica sol heel was prepared in situ at 70"C and pH of 9 by diluting 127 ml of 20% SiO2 sodium silicate JM (SiO2/Na2O weight ratio 3.25) to a total volume of 3000 ml with hot tap water to make 1.270 liters of 1% SiO2 heel (12.7 g SiO2 in 1270 ml of solution). The heel was heated to 70"C and then deionized to pH 9 + 0.1 with 80 g of ion exchange resin Amberlite < D IRC-84-S. AMBERLITE is a Registered Trade Mark.

Feed solutions were added in the manner explained in Example 1 of Application 36574/77 Serial No. 1587236 to buildup with sodium silicate and sodium aluminate, the sodium silicate solution at a rate of 12 ml/min and the sodium aluminate solution at a rate of 27 ml/min while simultaneously heating the heel to 100"C. Heating from 70C to 1000C took about 48 minutes. The two feed solutions of Example 1 of Application 36574/77 Serial No.

1587236 aqueous sodium silicate solution 20 g SiO2/100 ml and aqueous sodium aluminate solution 5 g NaAlO2/100 ml were used. In 4 minutes the pH of the heel rose to 11.3 due to the alkalinity of the feed solutions being added. From this point on the heel was kept at 11.3 + 0.1 by periodic additions of IRC-84-S resin.

A total of 3770 ml of sodium silicate solution, 8420 Pore volume distribution analysis was made based on the B. F. Roberts method [J.

Colloid and Interface Science 23, 266 (1967)] and the results computed and plotted using the PORDIS-PORTL computer program.

Eighty-four percent of the volume of the pores was constituted of pores ranging in diameter from 0.6 to 1.4 of the median pore diameter.

The powder was mixed with a rare earth zeolite Y and proved in testing to be an excellent catalyst for the cat-cracking of petroleum.

WHAT WE CLAIM IS: 1. An amorphous aluminosilicate powder as defined in any one of claims 1 to 14 of Application 36574/77 Serial No. 1587236 but having a uniform median pore diameter between the spheroidal particles in the range 45 to 250 , with pore diameters of 45 to 150A having a uniformity such that 80 to 90% of the pore volume is of pores of from 0.6D to 1.4D in size, where D is the median pore diameter, and with pore diameters of 150 to 250A having a uniformity such that at least 80% of the pore volume is of pores of from 0.6D to 1.4D in size.

2. A powder as claimed in claim 1 wherein the aggregates have an average diameter in the range 5 to 200 microns.

3. A powder as claimed in claim 1 substantially as described herein in Example 1 or Example 3.

4. A process as defined in any one of claims 16 to 29 of Application 36574/77 Serial No.

1587236 whereby a powder as claimed in claim 1 or claim 2 is produced.

5. A process as claimed in claim 4 substantially as described herein in Example 1 or Example 3.

6. An amorphous aluminosilicate powder when prepared by a process as claimed in claim 4 or claim 5.

7. A chemical process wherein a powder as claimed in any one of claims 1 to 3 and 6 is used as catalyst.

8. A process as claimed in claim 7 wherein the process is a petroleum refining process.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (8)

**WARNING** start of CLMS field may overlap end of DESC **. Pore volume distribution analysis was made based on the B. F. Roberts method [J. Colloid and Interface Science 23, 266 (1967)] and the results computed and plotted using the PORDIS-PORTL computer program. Eighty-four percent of the volume of the pores was constituted of pores ranging in diameter from 0.6 to 1.4 of the median pore diameter. The powder was mixed with a rare earth zeolite Y and proved in testing to be an excellent catalyst for the cat-cracking of petroleum. WHAT WE CLAIM IS:

1. An amorphous aluminosilicate powder as defined in any one of claims 1 to 14 of Application 36574/77 Serial No. 1587236 but having a uniform median pore diameter between the spheroidal particles in the range 45 to 250 , with pore diameters of 45 to 150A having a uniformity such that 80 to 90% of the pore volume is of pores of from 0.6D to 1.4D in size, where D is the median pore diameter, and with pore diameters of 150 to 250A having a uniformity such that at least 80% of the pore volume is of pores of from 0.6D to 1.4D in size.

2. A powder as claimed in claim 1 wherein the aggregates have an average diameter in the range 5 to 200 microns.

3. A powder as claimed in claim 1 substantially as described herein in Example 1 or Example 3.

4. A process as defined in any one of claims 16 to 29 of Application 36574/77 Serial No.

1587236 whereby a powder as claimed in claim 1 or claim 2 is produced.

5. A process as claimed in claim 4 substantially as described herein in Example 1 or Example 3.

6. An amorphous aluminosilicate powder when prepared by a process as claimed in claim 4 or claim 5.

7. A chemical process wherein a powder as claimed in any one of claims 1 to 3 and 6 is used as catalyst.

8. A process as claimed in claim 7 wherein the process is a petroleum refining process.