CH466235A - Process for preparing a catalyst - Google Patents

Description

  

  
 



  Process for preparing a catalyst
 The present invention relates to a process for preparing a catalyst and its use for the catalytic cracking of hydrocarbons.



   It has already been pointed out that various chemical reactions can advantageously be carried out by a contact catalysis process, using crystalline zeolites of the metal aluminosilicate type as catalysts having a rigid three-dimensional network consisting of unit cells characterized by the absence almost total variation in the dimensions of the unit cell when it is dehydrated and rehydrated, and by a very uniform homogeneous porous structure. The above conditions are fulfilled by certain crystalline zeolites called molecular sieves.



  Reactions effectively catalyzed by these bodies include, for example, hydrocarbon cracking, alkylation, dealkylation, disproportionation, isomerization and polymerization. Since these catalysts have the property of influencing and directing the course of chemical conversion, they have a remarkable degree of catalytic selectivity. In short. there are two types of selectivity: on the one hand, the geometric selectivity which depends on the relation between the diameter of the pores of the crystalline structure of the aluminosilicate zeolite and the diameter of the molecules of reagents and products, and of on the other hand, the intrinsic catalytic selectivity which depends on the choice of the cation present on the surfaces of the crystalline metallic aluminosilicate.



   A wide variety of zeolites of natural and synthetic origin are known, for example chabazite, gmelinite, mesolite, mordenite, natrolite, sodalite, scapolite, lazurite, leucrite and cancrinite.



  Synthetic zeolites can be of type A,
X, type Y or other well known forms of molecular sieve. The preparation of the above synthetic zeolites is described in the literature, for example that of zeolite A in US Pat. No. 2882,243 of April 14, 1959, that of zeolite X in US Pat. America No. 2882244 of April 14, 1959 and that of zeolite Y in Belgian patents Nos. 577642 and 598582. In the form initially prepared, the metal of the aluminosilicate is an alkali metal, usually sodium. This alkali metal can undergo base exchange with a wide variety of other metal ions.

   The molecular sieves thus obtained are remarkably porous, the pores exhibiting very uniform molecular dimensions, generally between 3 and 15 A in diameter approximately. Each molecular sieve crystal contains an extremely large number of tiny cavities or cages interconnected by channels of invariable diameter. The size and proportion of the metal ions contained in the crystal determines the effective diameter of the communication channels.



   It has been found that a highly active and selective catalyst for the conversion of organic compounds is prepared by contacting a crystalline alkali metal aluminosilicate, in which the silica / alumina molecular ratio is greater than 3, with a solution containing ions. of a metal lower than sodium in the electromotive series, calcium ions and / or organic nitrogen ions, so as to replace at least 70% of the alkali metal initially contained in the almminosilicate.



   The organic nitrogen ions can be quaternary ammonium ions, as well as those of guanidine salts and amine salts. Particularly preferred replacement ions are those of alkaline earth metals, those of rare earth metals and the manganese ion. The treatment solution may further contain ammonium ions and hydrogen ions.



   Before or after the ion exchange, the crystalline aluminosilicate, in finely divided form, can be intimately mixed with a suitable binder, under conditions such that the aluminosilicate is intimately distributed and remains in suspension in a matrix of the binder. In cases where the alkali aluminosilicate is initially mixed, the ion exchange is then carried out on the composition obtained.



   Unexpectedly, the catalyst thus obtained was found to exhibit greater activity and selectivity than comparable catalysts prepared from other synthetic aluminosilicates such as those of type X in which the silica: alumina molar ratio is lower. to 3: 1.



   Unlike the previously usual cracking catalysts, the catalyst prepared according to the invention is preferably prepared from a crystalline aluminosilicate of type Y having a structure with rigid three-dimensional networks characterized by uniform pores with a diameter of 6-15. And in which the original alkali metal has been replaced, preferably substantially all, by a metal lower than sodium in the electromotive series, by calcium, ammonium ions and hydrogen, separately or together. The uniform pore openings in the mentioned range come in all dimensions and allow access to the catalyst surface of all hydrocarbon reagent molecules and allow easy release of the product molecules.



  Further, unexpectedly, the catalyst has remarkable stability when in the form of hydrogen aluminosilicate or Y-type acid, which has been exchanged into a hydrous oxide matrix. The great stability of such a catalyst is attributable to the apparent synergistic action between the acid aluminosilicate and the hydrated oxide matrix which encloses it.



   In one embodiment of the process according to the invention, a finely divided crystalline aluminosilicate of type Y, the cation of which is constituted, separately or jointly, by ions of metals lower than sodium in the electromotive series, is intimately associated with a suitable binder. calcium, ammonium or hydrogen ions, the catalyst obtained having, after drying and calcination, an exchangeable alkali metal content of less than 3 Olo by weight.



   In another embodiment of the process according to the invention, a finely divided aluminosilicate Y in which at least 70% of the initial alkali metal content has been replaced by ions or several types chosen from the group is dispersed in a suitable matrix. which comprises the metals lower than sodium in the electromotive series, calcium, ammonium and hydrogen ions, this aluminosilicate having uniform pore openings of between 6 and 15 A approximately, then the catalyst obtained is dried, calcined and treated with water vapor at a temperature of 200 790O C for a time greater than approximately 2 hours.



   In another embodiment of said process, resulting in a catalyst intended for the conversion of hydrocarbons, a finely divided aluminosilicate Y given by the ion exchange described above is dispersed in an inorganic oxide sol. gelation of the sol containing the finely divided aluminosilicate, the catalyst obtained is washed to free it from soluble matters, dried, calcined and the calcined catalyst is treated with steam.



   In another embodiment of said process, the catalyst obtained comprises an aluminosilicate in suspension uniformly distributed in a gangue, the cation of the aluminosilicate being constituted by one or more ions from the group which comprises the metals less than sodium in the series electromotive, calcium, ammonium and hydrogen ions.



   In yet another embodiment, resulting in a cracking catalyst of exceptional activity and selectivity, the latter consists essentially of 1-90 by weight of a crystalline aluminosilicate of type Y resulting from 1. ion exchange mentioned, the particle size of the aluminosilicate being less than 40 microns and preferably less than 15 microns in diameter, and the aluminosilicate being distributed in suspension in a matrix of a hydrated oxide which may be formed clay or mineral oxide gels.



   In another embodiment of the process according to the invention, the catalyst obtained comprises spheroidal particles essentially formed of 1-50 by weight of an aluminosilicate resulting from an ion exchange as above, having an average diameter of particles of 2-7 microns, in suspension uniformly distributed in a matrix of mineral oxide gel which may be formed of alumina, silica or compounds formed by silica with at least one metal from groups IIA,
IIIB and WA of the periodic table.



   The use of the catalyst obtained by the process according to the invention consists in a catalytic conversion of organic compounds, in particular the catalytic cracking of hydrocarbon oils in the presence of said above catalyst and under cracking conditions, achieving an increased conversion of the raw material into useful products.



   Catalytic cracking is commercially carried out by bringing a hydrocarbon feedstock in contact, in the vapor state or in the liquid state, with a catalyst of the above type, under the desired conditions of temperature, pressure and time. to achieve almost complete conversion of the feed to lower boiling point hydrocarbons. The reaction which occurs is essentially cracking with the formation of lighter hydrocarbons but it is accompanied by several complex side reactions such as aromatization, polymerization, alkylation, etc.

   As a result of these complex reactions, a carbonaceous deposit (commonly called coke) is formed on the catalyst. The deposition of coke tends to seriously decrease the efficiency of the catalyst for the main reaction, and then the conversion stops once the coke has accumulated on the catalyst in the amount of a few units / o by weight.



  The surface of the catalyst is then regenerated by burning the coke in a stream of oxidizing gas and the catalyst is returned to the conversion stage of the cycle.



   As will be appreciated, coke and other undesirable products are formed at the expense of useful products such as gasoline. It is evident that during the regeneration time the catalyst is not effectively used for the conversion. Accordingly, it is very desirable not only to achieve a high overall conversion of the hydrocarbon feedstock, i.e. to adopt a high activity catalyst, but also to obtain an increased yield of useful product such as. gasoline while keeping unwanted products such as coke to a minimum. The ability of a cracking catalyst to thereby direct the course of the conversion is called selectivity.

   Thus, a very useful and highly desirable advantage for a cracking catalyst is high selectivity and also high steam stability, so that it withstands the steam treatment which serves to regenerate the catalyst.



  Preferably, a catalyst is used in a cracking process which consists essentially of a crystalline Y-type hydrogen aluminosilicate having a rigid three-dimensional network structure characterized by uniform pores of 6-15 diameter.



   It has been discovered that it is possible to effectively carry out the catalytic conversion of hydrocarbons in the presence of a very active and very selective catalyst essentially consisting of a crystalline hydrogen aluminosilicate of type Y. This latter aluminosilicate is obtained by preferably replacing almost all the alkali ions of a crystalline alkaline aluminosilicate of type Y by hydrogen ions. To make this replacement, the crystalline alkaline aluminosilicate of the type
Y in contact with a fluid containing hydrogen ions, under conditions such that the zeolite structure of the aluminosilicate is not destroyed.

   Another effective way to replace alkali ions is to contact the alkali aluminosilicate with a fluid containing ammonium ions, then heat the obtained ammonium aluminosilicate to effect the decomposition of ammonium ions with release of NH5, the ions hydrogen remaining in place of the initial ions. It has been found that cracking carried out using crystalline hydrogen aluminosilicate of the type
Y thus obtained gives a high yield of useful cracked products.



   The alkali metal aluminosilicates which can be used in the preparation of the catalyst by the process according to the invention are those which are called Y zeolites in the technique.



  The latter are particularly described in Belgian patents No. 577642 described above and No. 598582 described above and can be advantageously prepared by the process of these patents. The molar composition of these zeolites falls into the general formula:
 0.9 t 0.2 NIO GARLIC / OS. 3-6.5 SiO .9 HO.



  The above zeolite, used in the preparation of the present catalyst, exhibits a uniform pore structure comprising openings characterized by an effective pore diameter of 6-15.



   Such a catalyst is generally prepared by subjecting the crystalline alkali aluminosilicate Y above to a base exchange with ions of the type already mentioned, so as to replace at least 70O / o and preferably more than 80 / o of the alkali ions. initials. The electromotive series)> which we are talking about here is that defined in the Handbook of Chemistry and Physics, 431st edition, edited by Chemical Rubber Publishing
Company.

   These catalysts can be prepared by intimately mixing, on the one hand, a crystalline alkaline aluminosilicate Y having a rigid three-dimensional network structure characterized by an effective and uniform pore diameter of 6-15, in a finely divided form in which the particles generally have an average diameter of less than about 40 microns and preferably less than about 15 microns, on the other hand a suitable binder such as a metal powder, a clay or an inorganic oxide gel, then subjecting the composition obtained to an exchange of bases with almost complete elimination of the alkali metal, by treatment with a solution containing ions of one or more types chosen from the group which includes metals lower than sodium in the electromotive series, calcium, ammonium and hydrogen ions, and then,

   by washing, drying and calcining the composition obtained. Alternatively, preferably, the alkali aluminosilicate can be subjected to base exchange as above before it is thoroughly mixed with the binder. In this method, the mixture formed by the finely divided aluminosilicate is washed beforehand subjected to the exchange of bases, distributed and kept in suspension in a gangue of the binder, an exchange of bases is carried out if necessary to remove binding the zeolite alkali metal, dried and calcined as above. The exchangeable alkali metal content of the catalytic compositions obtained by the above processes is preferably less than 3 o / o and more especially less than 2 O / o by weight.



   The maximum alkali metal content that can be tolerated in the final catalyst composition depends in part on the nature of the cation present. Thus, when the cation is a rare earth metal or a combination of metal ions and hydrogen ions, up to 3% by weight of exchangeable alkali metal can be tolerated. In the case of manganese and alkaline earth metals such as calcium, the residual amount of exchangeable alkali metal is generally kept below 20% and preferably below 1.5% by weight.



   To obtain the intimate mixture of the finely divided aluminosilicate and the binder such as a metal powder, a clay or an inorganic oxide hydrogel, the two materials can for example be passed together in a ball mill for an extended time, from preferably in the presence of water, under the conditions desired to reduce the particle size of the aluminosilicate to an average diameter of less than 40 microns and preferably less than 15 microns. However, this mixing process is less advantageous than that which consists in dispersing the aluminosilicate in finely divided form in a hydrated inorganic oxide, for example a hydrosol or a hydrogel.

   According to this embodiment, the finely divided aluminosilicate can be dispersed in an already prepared hydrogel or hydrosol or, which is preferable when the hydrosol is characterized by a short gel time, the finely divided aluminosilicate can be added to a or more of the reagents which serve to form the hydrosol, or mix it, as a separate stream, with streams of hydrosol-forming reagents, in a mixing nozzle or other device in which the reagents are placed in intimate contact. As noted above, it is desirable that the aluminosilicate introduced into the hydrosol have an average particle diameter of less than about 40 microns and preferably less than 15 microns, and between 2 and 7 microns when desired. large particles.

   It has been found that the use of an aluminosilicate having an average particle diameter greater than 40 microns gives a physically small product, while the use of an aluminosilicate having an average particle diameter less than 1 micron gives a product of low diffusibility.



   The inorganic oxide hydrosol containing the powder sets into a hydrogel after an appropriate time and the resulting hydrogel is subjected to base exchange if zeolite alkali metal has been introduced due to the use. of an alkali silicate, and then washed, dried to a gel and thermally activated at a temperature above the melting point of the incorporated aluminosilicate powder. It has been found that the product obtained, which is essentially formed of an aluminosilicate of type Y, the cation of which consists, separately or jointly of a metal lower than sodium in the electromotive series, or of calcium, ammonium or hydrogen ions, and which in suspension uniformly distributed in a matrix of mineral oxide gel, has remarkable properties as a catalyst for the conversion of hydrocarbons.



   In addition to the aluminosilicate Y described above, it has been found desirable in certain cases to include in the catalyst matrix a secondary solid additive also in finely divided form, generally with an average particle diameter of between 1 and 40 microns, capable of making the composition more diffusible. This additive to be inert or else it can contribute to the overall catalytic activity of the final catalyst composition. The amount of this additive can be up to 40q) / o of the weight of the composition. Generally, when the catalyst is in the form of gel beads, the average particle diameter of the additive is less than 10 microns.

   Suitable additives for the above use are, for example, clay, alumina, zircon, barite, charcoal, wood powder, silica, recycled fine particles of catalyst, magnesia, spent fine particles. cracking catalysts, and various ores and natural rocks, These additives can remain in the final composition, or in the case of combustible materials such as charcoal or wood powder, they can be removed beforehand following a treatment of preparation applied to the catalyst, or as a result of its use at high temperature.



   The binder which constitutes the matrix of the catalyst must be thermally stable under the conditions in which the conversion reaction is carried out. Thus, it is contemplated to use solid porous adsorbents and supports of the type previously employed in catalytic operations, in conjunction with the crystalline aluminosilicate of type Y described above. These materials may be catalytically inert or they may possess intrinsic catalytic activity or activity attributable to close association or reaction with crystalline aluminosilicate type Y.

   These materials include, for example, dried gels of inorganic oxide and gelatinous precipitates of alumina, silica, zirconia, magnesia, hafnium oxide, thorium oxide, titanium oxide, boric anhydride and mixtures of these oxides with each other and with other constituents. Other suitable binders include activated metal powders, charcoal, mullite, kieselguhr, activated carbon, bauxite, silicon carbide, sintered alumina, and various clays. Preferably, the aluminosilicate is intimately associated with a hydrated oxide such as an inorganic oxide hydrogel or a clay, as indicated above.



   Although the inorganic oxide gels can be used as gangue in general, it is preferable that the inorganic gel is a cogel of silica and of an oxide of at least one metal of groups IIA, IIIB and IVA of the group. periodic classification. These constituents include, for example, silica-alumina, silica-magnesia, silica-zirconia, silica-hafnium oxide, silica-thorium oxide, silica-beryllium oxide, silica-ti aunt oxide. as well as ternary combinations such as silica-alumina-thorium oxide, silica-aluminezirconia, silica-alumina-magnesia and silica-magnesia-zirconia systems. In the above gels, silica is generally present as the main constituent and the oxides of metals are present in a minority.

   Thus, the silica content of these gels is generally between 55 and 1000 / o by weight, the metal oxide content varying from 0 to 45 o / o by weight. The inorganic oxide hydrosols used herein and the hydrogels derived therefrom can be prepared by any method well known in the art, for example, ethyl orthosilicate can be hydrolyzed, an alkali silicate acidified which can contain a compound of a metal whose oxide it is desired to coogelate with silica, etc.

   The relative proportions of finely divided crystalline aluminosilicate and gangue can vary widely, with the crystalline aluminosilicate constituting about 1-90%, and most usually about 1-50%, by weight of the composition, particularly when it is. ci is prepared in the form of beads.



   The catalyst can be prepared by the process according to the invention in any desired physical form. Preferably, it is used in the form of small fragments of the size most suitable for the job under the particular conditions in question. Thus, the catalyst may be in the form of a finely divided powder or in the form of grains 1.6-3.2 mm in size, which are obtained for example by agglomeration, molding or extrusion according to well known techniques. A hydrosol containing crystalline aluminosilicate powder can be allowed to solidify into a hydrogel which is then dried and divided into pieces of the desired size. The gel pieces thus obtained are generally irregular in shape.

   Uniform shaped gel pieces can be obtained by extruding or granulating the hydrogel containing the aluminosilicate. The hydrosol can also be introduced into the perforations of a perforated plate and held there until the sol has set into a hydrogel, after which the pieces of hydrogel formed are removed from the plate.

   A particularly practical method consists in preparing the catalyst in the form of spherical particles by dispersing the powdered aluminosilicate in a hydrosol and by introducing globules of the hydrosol obtained in a mass of liquid immiscible with water. for example in an oily medium in which the hydrosol globules take in hydrogel and then arrive in a lower layer of water from where they are removed for subsequent processing operations such as base exchange, washing with water, drying and calcination.

   The larger spheres are usually between 0.4 and 6.4 mm in diameter while the smaller spheres, generally called microspheres and formed by drying, spraying or other well known techniques, have a diameter of between 20 and 300. microns approximately. It is particularly advantageous to use particles of spheroidal shape in hydrocarbon conversion processes where the catalyst is subjected to continuous movement, such as the moving compact bed process, the fluidized bed process, etc. In the case of the immobile layer, the spheroidal catalyst particles ensure effective contact between the reactants and the catalyst by avoiding pathways.



   While the initial formation of a hydrosol which sets in a short time to give a hydrogel in the form of beads is one of the advantageous points in the manufacture of a spheroidal catalyst, it is also possible, particularly when preparing the catalyst in a form other than spheroidal, to use a matrix comprising a gelatinous precipitate of hydrooxide in varying degrees of hydration or a mixture of a hydrogel and a gelatinous precipitated gel. The word gel, used here, designates hydrogels, gela precipitates
 tinous and the mixtures of each other. On the other hand, the gangue can be constituted totally or partially by a clay, particularly a clay of the type of montmorillonites or kaolinites, crude or
 treated with acid.



   Another class of materials that can be used as gan
 gues includes powdered metals not subject to oxidation under the reaction conditions. Suitable metal powders include, for example, aluminum and iron alloys such as stainless steel and various other metals characterized by their stability under working conditions. Other clean materials
 To serve as gangue in the composition of a catalyst include charcoal, graphite, bauxite and other binders compatible with the crystalline metallic aluminosilicate and thermally stable under the temperature conditions in which the catalyst is used.



   As stated above, the crystalline alkali aluminosilicate Y is subjected to base exchange. Among the metals which can be used are manganese, alkaline earth metals such as calcium and magnesium, rare earth metals such as cerium, praseodymium, lanthanum, neodymium, samarium, gadolinium and their mixtures. The base exchange is carried out so as to replace at least 70 0 / o and preferably more than 80l / o of the initial alkali ions by ions of the group already mentioned, and to preferably reduce below 3 o / o the exchangeable alkali metal content of the finished catalyst.

   The aluminosilicate in finely divided form, bound as aggregate particles with a suitable binder or gangue, can undergo base exchange before or after intimate mixing with the binder. The base exchange is carried out by treating the product with a solution containing the ions which it is desired to introduce into the aluminosilicate. It is envisaged to use for the exchange of bases any ionizable compound providing ions of hydrogen, ammonium or the metals mentioned above. Usually an aqueous solution of these compounds is used.

   A particularly effective base exchange solution is one which contains one or more metals lower than sodium in the electromotive series and ammonium ions, including complex ammonium ions, the ratio of metal ions to ammonium ions being 10: 1 and 1: 100 so as to replace the alkali ion with the metal ions in question and the ammonium ions. merization of terpenes; The alkylation of isoparaffins and the dealkylation of aromatic hydrocarbons.



   The cracking of hydrocarbons represents a particularly advantageous application of the catalyst of the aluminosilicate type described here, since the nature of the products can easily be regulated. In this process, the catalyst can be used in the form of grains in a fixed bed operation, or in a moving compact bed or fluidized bed operation.



  General working conditions cover a wide range given the wide utility of catalysts. It is generally desirable to carry out these processes at a temperature between approximately 260 and 6500 C and at a pressure varying from a sub-atmospheric level to several hundred atmospheres. In any case, the contact time of the oil with the catalyst is adjusted according to the conditions, the particular raw material and the particular results which are desired, in order to obtain a notable cracking with formation of products with a lower boiling point.



   The cracking activity of the catalyst is a measure of its ability to catalyze various hydrocarbon conversions and is expressed herein as the percent conversion of a mid-US gas oil which has a boiling range. from 232-510 C to gasoline which has an end boiling point of 2100 C, when vapors of this gas oil are passed through the catalyst at 468-482O C, at approximately atmospheric pressure, with a flow rate of 0.6-16 volumes of liquid hydrocarbon per volume of catalyst per hour, with times of 10 minutes between regenerations.



   It has been found desirable, in order to analyze the results obtained with the catalysts described here, to compare them with the results obtained with a commercial cracking catalyst formed from silica and alumina gel and containing about 10% alumina by weight. The exceptional activity, stability and selectivity of the catalyst prepared by the process according to the invention are highlighted by the comparison of the product yields obtained with this catalyst and the product yields obtained with the usual silica-alumina catalyst, at same level of conversion.



   The following examples illustrate the invention.



   Example I
 Crystalline sodium aluminosilicate type Y can be prepared from the following reagents:
   A - Silica solution
 1551 cm (1870 g) of colloidal silica containing
 0.361 g of SiO2 per cm
   B - Sodium aluminate solution
 75 g of NaAIOg (41.7% by weight of Al2O3,
   30 oxo by weight of Na2O)
 330 g of NaOH (77.5% by weight of H2O)
 1345 cm3 of H2O
 The above solutions are mixed at about 270 ° C. pouring solution B into solution A. The mixture is stirred vigorously for about 1/2 hour. Then the slurry obtained is subjected to a heat treatment at about 93O C for 42 hours. The solid material is then filtered off from the supernatant liquid.



  The cake is washed with one volume of water per volume of initial slurry to remove free caustic.



   To prepare the catalyst of this example, 10% by weight of the Y zeolite prepared for example as above is dispersed in a matrix of silica-alumina gel containing approximately 94% of silica and 6 oxo of alumina by weight. .



   The following reagents are used:
   C - Silicate solution
 1. 4.74 kg of sodium silicate (28.5% SiO2,
 8.9% Na2O, 62.6% H2O by weight)
 2.39 kg of water
 2.24 kg of water
 0.30 kg of sodium aluminosilicate Y
   (54.3 0 / o by weight of solids)
 Solution 2 is added to solution 1 with vigorous stirring, to obtain a solution which has a density of 1.182 at 160 C.



   D - Acid solution
 25.90 kg of water
 1.92 kg of Al2 (SO4) 3.18H2O
 0.90 kg of H2SO4 (at 97 0 / o)
 density at 250 C: 1.056
 The above solutions are passed through a mixing nozzle at a rate of 394 cm3 / min of solution D for 374 cm3 / min of solution C. The hydrosol obtained has a pH of 8.5; it is introduced in the form of globules in a mass of oil where it sets in hydrogel beads in 2.2 seconds at 170 C.



   The hydrogel in beads is subjected to a base exchange with an aqueous solution of 2 oxo by weight of rare earth chloride containing: 0.63 0 / o of cerium chloride, 0.33 331O / o of lanthanum chloride, 0.06% praseodymium chloride, 0.23% neodymium chloride and traces of samarium chloride, gadolinium chloride and other rare earth chlorides. The base exchange is carried out using 12 contacts (9 contacts of 2 hours each and 3 contacts of 20 hours each) with 1/2 volume of solution for 1 volume of hydrogel beads.

   The hydrogel which has undergone the exchange to rid it of soluble anions is washed, dried for 24 hours in air at 1320 C, conditioned in air for 10 hours at 5380 C and treated with steam. of water at 1.05 kg / cm2 and 6490 C, for 30 hours and for 60 hours.



   The finished catalyst contains 0.21 0 / o by weight of sodium and its content of rare earth oxides is
   10.8% by weight. The specific surface area of the product steamed for 30 hours is 195 m2 / g and that of the product steamed for 60 hours is 167 m2 / g.



   Table I
Example No 1
Description
 Gangue .............. Si / Al (94/6)
 Fine particles:
 Type .................. Na / Al / Si (13Y)
 Concentration ......... 10
Exchange of bases
 Solution ................... RECl3.6H2O
 Concentration,% by weight .. 2
Composition
 Na, wt% .......... 0.21
   (TR) 2O2 by weight (.:

  .) 10.8
 Table I (continued)
Physical properties
 Specific surface m2 / g
 after steam treatment. . 195 (1) 167 (2)
Catalytic evaluation
 Converstion,% by volume ... 63.0 60.8
 Relative flow, h-1 ......... 4 4
 Diesel 10 RVP, / o by volume 55, 2 53.7
 C4 'excess,% by volume ... 10.2 10.8
 C5 + gasoline,% by volume. 52.5 51.1
 Total C4 ',% by volume .... 12.9 13.3
 Dry gas, wt% ....... 6.4 5.1
 Coke,% by weight .......... 2.4 2.3
Advantage over usual cracking catalyst (**) (1) (2) 10 RVP,% by volume. . . @ +8.8 +8.5
 Excess C4 ,, / o in volume. . . @ 9
 C5 + gasoline,% by volume. +8.4 +8.5
 Total C4 ',% by volume .... -4.2 -3.2
 Dry gas,% by weight .......

   -1.8 -2.6
 Coke, wt% .......... -2.7 -2.5
 Increased yield
 in C5 + gasoline. compared
 to SiO2 / Al2O1-REHX (** *) +2.2 +2.4
 (*) TR = rare earth metals
   (**) Commercial silica-alumina catalyst containing
 about 99% of SiO2 and 10% of Al2O3 (***) 13X zeolite having undergone a base exchange with
 rare earth and ammonium chloride. and con
 held in a SiO2-Al2O3 gel matrix
 (1) Treated for 30 hours at 649 C and 1.05 kg / cm2 with
 100% water vapor
 (2) Treated 60 hours at 6490 C and 1.05 kg / cm2 with
 100% water vapor.



   As can be seen, the data relating to the catalyst of Example 1 is compared with the results obtained using a commercial silica-alumina cracking catalyst at the same conversion, and also with the results of a catalyst comprising 10%. by weight of sodium aluminosilicate of type X dispersed in a gel matrix comprising 94% silica and 66% alumina by weight, the catalyst having undergone base exchange with combined solutions of rare earth chloride and ammonium, to a low residual sodium content.



   The data in Table I demonstrate the catalytic advantages of the gangue type Y exchanged aluminosilicate over the comparable type X aluminosilicate, as well as the very significant improvement in activity and selectivity compared to the commercial catalyst. usual silica-alumina.



   Examples 2-3
 The catalysts of these examples are prepared in the same manner as that of Example 1, except that the base exchange of the beaded hydrogel is carried out with an ammonium chloride solution.



   Thus, the exchange of the hydrogel in beads for these two examples is carried out by contact with an aqueous solution containing 1% by weight of ammonium chloride, using 12 contacts of 2 hours each with 1/2 volume of solution per hydrogel volume. The hydrogel is then washed, dried and conditioned as in Example 1. The catalyst of Example 7 is steamed for 30 hours at 1.05 kg / cm2 and 6490 C while the catalyst of Example 8 is treated for 24 hours under the conditions indicated.



   Example 4
 The catalyst of this example is prepared by subjecting to base exchange 200 g of zeolite Y, which has been prepared for example as mentioned in example 1, with a 5% by weight aqueous ammonium chloride solution. The base exchange is carried out at 820 ° C. using 12 contacts of 2 hours each with 1/2 volume of solution per volume of slurry. The catalyst thus exchanged is washed, dried and conditioned as in Example 1, then treated with steam at atmospheric pressure for 20 hours at 6630 C.



   The catalyst thus obtained contains 1.19% sodium and 27.0% alumina by weight and has a specific surface area of 66 m2 / g.



   Example 5
 The catalyst of this example is prepared for comparison in the same way as for example 2, except that the sodium aluminosilicate is of type X and that it is present in an amount corresponding to 25% by weight. .



   A base exchange of the hydrogel beads of this example is carried out with a 2% by weight aqueous solution of ammonium chloride at room temperature, using 8 contacts of 2 hours each with 1/2 volume of solution by volume. of hydrogel beads.



  The exchanged hydrogel is then washed to rid it of chloride, dried in air at 1100 C, conditioned in air at 5380 C for 10 hours and treated with water vapor at 1, 05 and 649 C for 24 hours.



   The cracking activity of the catalysts of Examples 2-5 was checked as described above, and the results are shown in Table II:
 Table II
Examples N s 2 3 4
Description
 Gangue .................. Si / Al (94/6) Si / Al (94/6) Si / Al (94/6)
Fine materials
 Type ................... Na / Al / Si (13Y) Na / Al / Si (13Y) Na / Al / Si (13Y) Na / Al / Si ( 13X)
 Concentration .............. 10 10 100 25
Exchange of bases
 Solution .......................

   NH4Cl NH4Cl NH4Cl NH4Cl
 Concentration,% by weight ....... 1 1 5 2
 Table II (continued)
Examples NOS 2 3 4 5 **
Composition
 Na, wt% .............. 0.27 0.3 1.19 1.09
 Al2O3, wt% ........... 8.1 27.0 13.6
Physical properties
 Apparent specific weight g / cm2. . . @ 0.86 0.82 0.66 0.81
 specific surface,
   m2 / g after steam treatment. . 137 136 66
Catalytic evaluation
 Conversion,% in volume ....... 43.2 60.3 51.3 43.3 61.9 53.2 30.0
 Relative flow, h- ............. 4 2 3 4 2 4 4
 10 RVP diesel. % by volume @ 38.3 49.4 43.7 37.9 50.7 47.2 27.5
 Excess C4, / o in volume. . . @ 7.6 12.7 10.5 7.5 13.1 9.3 4.2
 C5 + gasoline,% by volume 36.3 47.1 41.7 36.0 48.5 44.7 25.8
 Total C4, / o in volume ......

   9.6 14.9 12.4 9.4 15.4 11.8 5.8
 Dry gas,% by weight .......... 4.5 7.4 5.7 4.4 7.4 5.2 3.1 Coke, 0 / o - by weight 0.9 1, 7 1.1 1.26 2.0 0.99 1.0
Advantage over usual cracking catalyst (*) 10 RVP, e / o by volume +2.5 +4, 3 +3.4 +2.1 +4.9 +59
 C4 excess,% by volume ......... -0.9 -1.1 -0.5 -1.1 -1.4 -2.2
 C5 + gasoline, 0 / o by volume +2.8 +4.3 +3.7 +2.5 +4.9 +5.7
 Total C4. % by volume ......... -1.4 -1.1 -0.9 -1.6 -1.2 -2.0
 Dry gas,% by weight .......... -0.4 -0.4 -0.5 -0.6 -0.6 -1.3
 Coke,% by weight ..............

   -1.0 -3.0 -2.2 -0.7 -2.8 -2.4
 (*) commercial catalyst formed from silica-alumina cogel containing approximately 9O0 / o SiQ2 and 10 0 / o M200
 (**) for comparison
 The catalytic data in the table above show that the Y aluminosilicates are active cracking catalysts which have better selectivity than the usual silica-alumina catalyst. In order to make a direct comparison between the catalysts of Examples 2 and 3 and the rare earth catalyst of Example 1, the former should be operated under conversion conditions at a relative flow rate of 2 h-1. At this flow rate, the activities of the catalysts of Examples 2 and 3 are respectively brought to 60.3 and 61.9% conversion by volume.

   These acid catalysts exhibit good selectivity at this level of conversion, the selectivity being improved to the detriment of coke and dry gas, with a low loss on the total C4.



   The data in Table II further show that the catalyst of Example 2, containing 10 0 / o by weight of sodium aluminosilicate Y, approaches the activity of the pure material, which is the catalyst of Example 4, even though it has been steamed much harsher. These data show that when a Y-type aluminosilicate is incorporated into a silica-alumina matrix and then a base exchange is carried out with an ammonium chloride solution, the stability of the aluminosilicate is increased. Although the reason for this unexpected increase is not known with certainty, it appears to be due to the synergy between the type Y aluminosilicate acid and the matrix that contains it.



   It can also be seen from the data in Table II that the comparative catalyst of Example 5 prepared from type X aluminosilicate is much less
 active than the catalyst of example 2 which contains a smaller amount of the aluminosilicate, but of type Y.



   The following examples serve to demonstrate that hydrated alumina and hydrated clay can be used.
 as gangue to prepare catalysts diluted with
 type Y rare earth aluminosilicate, exhibiting exceptional catalytic properties.



   Example 6
 The crystalline sodium aluminosilicate Y mentioned in Example 1 is used. 230 g of this product are subjected to base exchange with a combined aqueous solution containing 5 / o by weight of LaCl3.6H2O and 20 / o by weight. of NH4C1 for 48 hours continuously, using the equivalent of 24 changes of
 2 hours, with one volume of solution per volume of slurry. The exchanged material is washed to free it from soluble anions and dried.



   30 g of the powder, dried are mixed with 90 g of hydrated alumina containing 66.5% solids to
 5380 C. Mixing is carried out in a mixer by adding 150 cm3 of water to dilute the mixture into a homogeneous mass. The mixture was dried in air at 110 C for 24 hours, then granulated and sieved into particles of 4.8 X 2 mm. The particles were calcined for 10 hours at 5380 C and then steam treated for 24 hours at 6490 C and 1.05 kg / cm2.



   The catalyst obtained contains 0.3% by weight of sodium, 4.25% by weight of La2O3 and has a specific surface area of 172 m2 / g after treatment with steam.



   Example 7
 The catalyst is prepared as in Example 6, except that the base exchange solution contains 5% by weight of rare earth metal chloride (TRCl3.



  6H2O) and 20 / o by weight of ammonium chloride and that a hydrated clay is used as diluent matrix.



   In this example, 22 g of the exchanged and dried material are mixed with 76 g of crude clay (88% solids) at 5380 C. The dry mixed product is then granulated, calcined and steamed as in. the previous example.



   The finished catalyst contains 0.44% by weight sodium, 4.0% by weight rare earth oxide and has a specific surface area of 105 m2 / g after steam treatment.



   The characteristics and the results obtained in testing the catalysts of Examples 6 and 7 with regard to their cracking activity are shown in Table III:
 Table 111
Examples NOS 6 7
Description
   75 .0 / o alumina 75 0 / o clay
 Gangue ............ hydrated hydrated
Fine materials
 Type LaHY TRHY
 Concentration 25 25
Composition
 Na, wt% ..... 0.3 0.44
 (TR) 2O3, / o by weight. 4.25 4.0
Physical properties
 Specific surface
 after treatment
 steam, m2 / g. . . . 172 105
Catalytic evaluation
 Conversion,
 % by volume ..... 64.5 77.2 66.8 Relative flow, h-1. . .

   @ 4 4 8
 Diesel, 10 RVP,
   e / o in volume 59.2 60.6 65.1
 C4 excess,% by volume 8.9 16.2 11.8
 C5 + gasoline,
   '/ o by volume .... .. 55.9 58.1 55.1
 Total C4,% by volume 12.2 18.8 14.8
 Dry gas,% by weight. 5.6 10.1 6.3
 Coke,% by weight. . . @ 2.0 4.4 2,
Advantage over the usual cracking catalyst (*)
 10 RVP,% by volume. +12.2 +8.6 +10.1
 C4 excess, / o in volume - 6.5 -5.4 - 4.7
 Table 111 (continued)
Examples NOS 6 7
 C5 + gasoline.



   % in volume. .. +11.1 +7.7 +9.1
 Total C4, 1 / o by volume. - 5.4 -4.4 - 3.7
 Dry gas,% by weight. - 2.9 -0.9 - 2.6
 Coke,% by weight. . . . - 3.4 6-3, - 3.2
 Yield advantage
 in petrol C5 +
 compared
 to SiO2 / Al203-REHK (**) +5.1 - +3.2
 (*) Commercial silica-alumina catalyst containing
 about 90% SiO2 and 10% Al2O3
 (**) 13X zeolite having undergone a base exchange with
 rare earth and ammonium chlorides and
 contained in a SiO2-Al203 gel matrix.



   Example 8
 This example demonstrates that a catalyst exhibiting good activity and selectivity can be prepared by using a rare earth aluminosilicate Y which has undergone a pre-exchange, together with additional pulverized material to increase diffusibility. The fines consist of 5% by weight of rare earth aluminosilicate Y and 24% by weight of clay which has an average particle diameter of 4-5 microns. The resulting beaded hydrogel is subjected to base exchange, washed, dried, conditioned and steamed.



   The finished catalyst contained 0.18% by weight sodium, 0.950% by weight rare earth oxide and 16.60% by weight alumina. The specific surface area of the composition after steam treatment is 126 m2 / g.



   Table IV shows the results given by the cracking activity test of the catalyst of this example:
 Table IV
Example NO 8
Description
 Gangue ......... Si / Al (94% SiO2-6% Al2O3)
Fine materials
 Type ........... 5% REY + 24% clay
 Concentration
Exchange of bases
 NH4C1 solution
 Concentration,
 % by weight 1
 Contacts. 1-24 hours continuous at
 room temperature, equi
 equal to 12 changes of
 2 hours
Composition
 Na,% by weight. . . . 0.18
   (TR) 2O5, / o by weight. 0.95
   A1205, / o by weight .. 16.6
 Table IV (continued)
Example NO 8
Physical properties
 Specific weight
 apparent, g / cm3. . . . 0.78
 Specific surface
 after treatment
 steam, m2 / g. . .

   126
Catalytic evaluation
 Conversion,
 % by volume ..... 51.6
 Relative flow, h-1 ... 4
 10 RVP diesel,
   0 / o by volume 46.4
 C4 excess,
 % by volume ..... 7.0
 C5 + gasoline,
   0 / o in volume 43.6
 Total C4,% by volume 9.9
 Dry gas,% by weight. 50.0
 Coke,% by weight ... 1.2
Advantage over usual cracking catalyst (;)
 10 RVP, / o in volume +5.9
 C4 excess,
 % by volume ..... -4.0
 C5 + gasoline,
 % by volume ..... +5.4
 Total C4,% By volume -3.4
 Dry gas,% by weight. -1.2
 Coke, 0% by weight. . . -1.9
   (:) Commercial silica-alumina catalyst containing
 about 90% SiO2 and 10% Al2O3.



   Example 9
 This example demonstrates the use of a powdered metal as gangue for the above catalysts.



   One starts with a Y zeolite as in Example 1 and is subjected to base exchange with an aqueous solution containing 2% by weight of ammonium chloride and 5% by weight of mixed earth chlorides. rare products with the following composition: 1.57% cerium chloride, 0.83% lanthanum chloride, 0.17% praseodymium chloride, 0.58% neodymium chloride and traces of samarium chloride, gadolinium chloride and other rare earth chlorides. The base exchange was carried out continuously for 48 hours at 820 ° C. using the equivalent of 24 2 hour changes with 1 volume of solution per volume of slurry.

   The exchanged material is then washed to free it from chloride, it is dried for 24 hours at 1100 C, it is conditioned at 5380 C for 10 hours in air and finally it is brought into contact with 100% water vapor at the atmospheric pressure and at 6630 C for 20 hours. The residual sodium content of the exchanged material is 1.32% by weight. The exchanged aluminosilicate is mixed with aluminum powder, in an amount of 50 g of the aluminosilicate and 150 g of metallic aluminum powder, in a ball mill for 4 hours. The mixture is then granulated, sieved into 4.8 X 2 mm particles, conditioned for 10 hours at 5380 C in air and finally steamed for 24 hours at 649 C and 1.05. kg / cm2.



   The catalyst obtained contains 0.09% by weight of sodium and 2.76% by weight of rare earth oxides. The specific surface of the composition after steam treatment is 76 m2 / g.



   Table V shows the results obtained by checking the cracking activity of the catalyst of this example.



   Table V
Example NO 9
Description
 Gangue ............... metallic aluminum
 in powder
Fine materials
 Type REHY
 Concentration ........ 25%
Composition
 Na, 0% by weight. . . . 0.09
 (TR) 2O3,% by weight. . 2.76
Physical properties
 Apparent specific weight,
 g / cm3 0.76
 Specific surface after milking
 steamed, m2 / g. . 76
Catalytic evaluation
 Conversion,% by volume. 71.9
 Relative flow, h-1 ...... 4
 Diesel 10 RVP,% by volume 64.3
 Excess C4, / e in volume. . 12.0
 C5 + gasoline,% by volume. 61.1
 Total C4,% by volume. . . @ 15.3
 Dry gas, / o by weight. . . 5.9
 Coke, wt% ...... 2.6
 H2, wt% ........ 0.02
Advantage over usual cracking catalyst (:

  )
   10RVP, io / o in volume @ +14.2
 Excess C4, 0 / o by volume. . - 6.9
 C5 + gasoline, 0 / o by volume + + 12.8
 Total C4, 10 / o by volume. . . 5 5.5
 Dry gas, wt% ..... -3.9
 Coke, wt% ......... -4.2
 (*) Commercial catalyst containing approximately 90%
 SiO2 and lO0 / o Al2O3.



   It can be seen from the above data that the catalyst obtained, containing 25% by weight of rare earth aluminosilicate and of hydrogen, has superior catalytic properties. The catalytic data summarized in Table V show that this catalyst is extremely selective and gives an advantage of about 12.8% by volume of C5 + gasoline over the usual silica-alumina catalyst.



   Example 10
 To prepare the catalyst of this example, sodium aluminosilicate Y was continuously base exchanged with a combined solution comprising 5 wt% CaCl2 and 2 wt% NH4Cl at 820 C for 72 hours, using total solution equivalent to 36 changes of 2 hours with 1 volume of solution per volume of slurry.



   The exchanged product was washed, dried, conditioned and steamed for 24 hours at 6490 C and 1.05 kg / cm2.



   The composition, properties and results of the cracking activity test are shown in the table
VI.



   Table VI
Example NO 10
Description ........ aluminosilicate
 sodium
 Type .............. Na / Al / Si (13Y)
 Concentration 100
Exchange of bases
 Solution ................. CaCl2 + NH4Cl
 Concentration,% by weight. 5 2
 Contacts ................. 3 X 24 hours continuous,
 equivalent to 36 changes
 2 hours
Composition Na, 0 / o by weight 0.82
 Ca,% by weight. . . . 6.8
Physical properties
 Specific surface after
 steam treatment, m2 / g 187
Catalytic evaluation
 Conversion,% by volume. 61.8
 Relative flow, h-1 ....... 10
 10 RVP diesel,
 % by volume .............. 57.0
 Excess C4, 0 / o by volume. . 9.5
 C5 + gasoline,% by volume 54.0
 Total C4,% by volume. . 12.5
 Dry gas,% by weight. . . 4.8
 Coke, wt% ........

   1.5
Advantage over usual cracking catalyst (*)
 10 RVP,% by volume ... +11.2
 C4 excess, 0 / o in volume ... - 4.8
 C5 + gasoline,% by volume +10.4
 Total C4,% by volume ... -4.1
 Dry gas, wt% ..... -3.2
 Coke, wt% ....... -3.3
 Yield advantage
 in petrol C5 +
 on REHX (**) ...... + 2,4
 (*) Commercial catalyst containing approximately 90 0 / o
 SiO2 and 10% A1203
 (**) 13X zeolite having undergone a base exchange with
 a solution of rare earth chlorides and ammonium.



   The following example serves to illustrate that an effective catalyst can be prepared by subjecting sodium aluminosilicate Y to base exchange with a solution containing manganese and ammonium cations.



   Example 11
 The catalyst is prepared by subjecting to a continuous base exchange 300 g of sodium Y aluminosilicate with an aqueous solution containing 2% by weight of manganese chloride and 10% by weight of sodium chloride. ammonium. Base exchange is equivalent to 36 contacts of 2 hours with 1 volume of solution per volume of slurry. The product is then washed with water to remove the chloride ions, dried for 20 hours in air at 1320 C and steamed for 24 hours at 6490 C and 1.05 kg / cm2.

 

   The catalysts thus obtained have a sodium content of 1.4% by weight and a specific surface area after steam treatment of 52 m2 / g.



   Table VII shows the results given by the cracking activity test of this catalyst.



   Table VII
Example N 11
Description .............. aluminosilicate
 sodium type Y
Exchange of bases
 Solution ............... MnCl2 + NH4Cl
 Concentration,% by weight. 2 1
 Contacts ............... equivalent
 to 36 changes
 of 2 hours Composition
 N / A. % by weight ......... 1.4
Physical properties
 Specific surface after
 steam treatment, m2 / g. . 52
Catalytic evaluation
 Conversion,% by volume ...



   Example 12
 230 g of zeolite Y, prepared for example as described in Example 1, were subjected to a base exchange with an aqueous solution containing 50% by weight of a mixture of rare earth chloride having the following composition: 1 , 57% cerium chloride, 0.83 <? / O lanthanum chloride, 0.17% praseodymium chloride, 0.580 / o neodymium chloride and traces of samarium chloride, gadolinium chloride and other rare earth metal chlorides.



  The base exchange was carried out continuously for 72 hours at 820 ° C using the equivalent of 36 2 hour changes with one volume of solution per volume of suspension. Then, the base exchanged material was washed until it was free from chloride, dried for 24 hours at 110o C, calcined at 5380 C for 10 hours in air and it was finally contacted with 100% steam at atmospheric pressure for 20 hours at 663 C.



   The catalyst thus obtained has a sodium content of 0.820% by weight and a rare earth metal oxide content of 17.2% by weight and a specific surface area of 512 m2 / g.



   Example 13
 230 g of zeolite Y, prepared for example as described in example 1, were subjected to a base exchange with an aqueous solution containing 5 oxo by weight of the chlorides of rare earth metals having the composition indicated in the example. 12 and 2% by weight of ammonium chloride. The base exchange was carried out continuously for 48 hours at 820 ° C using the equivalent of 24 2 hour changes with one volume of solution per volume of suspension.



  The base exchanged material was then washed with water, dried, calcined and steamed as in the previous example.



   The catalyst thus obtained has a sodium content of 0.99% by weight and a rare earth metal oxide content of 17.7% by weight and a specific surface area of 472 m2 / g.



   To compare the above catalysts, based on type Y zeolite, with catalysts prepared from type X zeolite, the following examples were carried out:
 Example 14 (comparative)
 A crystalline sodium aluminosilicate type X was prepared by mixing the following solutions:
A. Sodium silicate solution
 77.5 kg of sodium silicate containing 8.8% by
 weight of Na2O, 28.5% by weight of SiO2
 and 62.7% by weight of H2O
   11.0 kg of sodium hydroxide
 143.0 kg of water.



  B. Sodium aluminate solution
 25.6 kg of sodium aluminate
 11.0 kg of sodium hydroxide
 195.0 kg of water.



   Solution B, having a specific gravity of 1.140 at 20.00 C, was added to solution A, having a density of 1.172 at 200 C, with vigorous stirring until a creamy suspension was obtained. This suspension was heated for 12 hours at 960 ° C., then filtered.



  The cake was washed with water until the water in equilibrium with the washed solid had a pH of 11. Then, the washed cake was dried in air at a temperature of 1380 ° C.



   680 g of zeolite X, prepared as described above, were subjected to base exchange with an aqueous solution containing 5 0 / o by weight of a mixture of rare earth metal chloride, by proceeding as described in example 12.



   The catalyst thus obtained has a sodium content of 0.530% by weight, a rare earth metal oxide content of 28.910% by weight and a specific surface area of 423 m2 / g.



   Example 15 (comparative)
 680 g of zeolite X, prepared as in Example 14, was subjected to base exchange with an aqueous solution of rare earth metal chloride and ammonium chloride as in Example 13.



   The catalyst thus obtained has a sodium content of 0.26% by weight, a rare earth metal oxide content of 26% by weight and a specific surface area of 497 m2 / g.



   The catalysts of Examples 12 to 15 were evaluated for their catalytic activity for cracking by charging a gas oil, as described above, at a temperature of 4820 C and at atmospheric pressure, using a flow rate of 16 volumes of liquid oil per hour and per volume of catalyst.



   The results of these tests are given in Table VIII below:
 Table VIII
Example NO 12 13 14 15
Description Sodium aluminosilicate
 Type ................... Na / Al / Si (13Y) Na / Al / Si (13Y) Na / Al / Si (13Y) Na / Al / Si ( 13Y)
 Concentration 100 100 100 100
Exchange of bases
 TRCl8 solution. 6:00 AM TRCl8. 6H20 + NH4Cl TRCl3. 6H2O TRCl3. 6H2O + NH4Cl
   Concentration, e / o by weight. . 5 5 2 5 5 2 Coznposition
 Na,% by weight ........... 0.82 0.99 0.53 0.26
 (TR) 2O3, wt% ..... 17.2 17.7 28.9 26
 Table VIII (continued)
Example NO 12 13 14 * 15 *
Description Sodium aluminosilicate
Physical properties
 Specific surface
 after steam treatment,
 m2 / g (1) ............... 512 472 423 497
Catalytic evaluation
 Conversion,% by volume. .

   61.7 68 59.1 59
 Relative flow, h-1 ........ 16 16 16 16
 Gasoline 10 RVP,% by volume 53.7 57.4 49.6 47.8
 Excess of C4,% by volume. 10.6 13.4 10.5 12.5
 C5 + gasoline,% by volume @ 51.0 54.8 47.4 45.8
 Total C4, 1 / o by volume. . . @ 13.3 16.0 12.8 14.5
 Dry gas, wt% ...... 6.5 7.3 6.4 6.8
 Coke, / o by weight ....... 2.5 2.8 3.6 3.5
Advantage over usual cracking catalyst (2)
 10 RVP,% by volume ..... +8.0 +8.8 +5.2 +3.4
 Excess C4, O / o in volume. . . 9-3, 6-3, 0-1, 0
 C5 + gasoline,% by volume. +7.5 +8.2 +5.2 +3.8
 Total C4,% by volume. . . -3.3 -3.0 -2.8 -1.1
 Dry gas, wt% ......

   -1.5 -1.9 -1.1 -0.7
 Coke,% by weight ........ -2.3 -3.2 -0.9 -0.9 (1) Catalyst steamed for 20 hours at 6630 C with steam at 1000 / o at atmospheric pressure.



  (2) Silica-alumina cogel catalyst containing approximately 90% SiO2 and 10% Al2O3.



   * for comparison
 The results collated in the table above show that the catalysts of Examples 12 and 13, based on aluminosilicate of type Y, are more active and more selective than the catalysts of Examples 14 and 15, prepared under comparable conditions but at from type X aluminosilicate.

   In particular, the results presented in Table VIII show that the catalyst of Example 12 is more active and much more selective than the catalyst of Example 14. It is also interesting to note that the catalyst of Example 14, subjected to an exchange essentially in the same manner as that of Example 12, retained 28.90 / o by weight of rare earth metal oxides, while the catalyst of Example 12 retained only 17.2 10% by weight, showing the differences between Y-type and X-type zeolites in exchangeability.

   Example 13 demonstrates the improvement in properties. catalytic which results from the combined exchange with rare earth metals and ammonium versus exchange with rare earth metals alone, as well as the catalytic improvement of the Y-type aluminosilicate, subjected to the rare earths / ammonium exchange relative to the aluminosilicate of type X, subjected to a corresponding exchange, of Example 15. Thus, as is clear from a comparison between the results of Examples 13 and 15, the catalyst of Example 13 is much more active and selective than that of Example 15.



   CLAIMS
 I. Process for preparing a catalyst, characterized in that a crystalline alkali metal aluminosilicate, in which the silica / alumina molecular ratio is greater than 3, is brought into contact with a solution containing ions of a metal. lower than sodium in the electromotive series, calcium ions and / or organic nitrogen ions, so as to replace at least 70iO / o of the alkali metal initially contained in the aluminosilicate.
  

 

Claims (1)

II. Use of the catalyst obtained by the process according to claim I for the cracking of hydrocarbons. SUB-CLAIMS 1. Method according to claim Ì, characterized in that said solution also contains hydrogen and / or ammonium ions. 2. Method according to claim I or sub-claim 1, characterized in that said solution contains ions of a rare earth metal. 3. Method according to claim I, characterized in that the exchangeable alkali ion content is lowered below 3 / o by weight. 4. Method according to claim I, characterized in that the reaction product is dried and calcined. 5. Method according to claim I, or sub-claim 1, characterized in that said solution contains ions of a rare earth metal, of an alkaline earth metal and / or of lanthanum. 6. Method according to claim I, characterized in that said solution contains ions of magnesium and / or manganese. 7. Method according to sub-claim 1, characterized in that the ions present comprise calcium ions and ammonium ions and in that the metal: ammonium ion ratio is between 10: 1 and 1: 100. 8. Method according to claim I, characterized in that the exchangeable alkali ion content of the aluminosilicate is reduced to below 3 '/ o by weight. 9. The method of sub-claim 4 or 5, characterized in that the calcined product is treated with water vapor between 200 and 8200 C for at least about 2 hours. 10. The method of claim I, characterized in that one starts with an aluminosilicate of type Y. 11. The method of claim I, characterized in that one increases the diffusibility of the catalyst by adding a finely divided solid additive. 12. Method according to sub-claim 1 or 2, characterized in that said solution contains metal ions and ammonium ions in a respective ratio of between 10: 1 and 1: 100.