MXPA98009937A - Ceolita catalyst contains metal, its preparation and use for hydrocarbon conversion - Google Patents

Abstract

A zeolite catalyst linked to zeolite is provided which does not contain significant amounts of non-zeolitic binder and a process for converting hydrocarbons using the zeolite catalyst linked to zeolite. The catalyst comprises a first zeolite, crystals, a binder comprising crystals of a second zeolite and a hydrogenation / dehydrogenation metal. The zeolite catalyst linked to zeolite is prepared by converting the silica binder from a silica bonded aggregate containing the first ristals of said first zeolite and at least a portion of the hydrogenation / dehydrogenation metal to said second zeolite, conversion processes such as Naphtha reformation, xylene isomerization / ethylbenzene conversion, and the zeolite catalyst linked to zeolite has an excellent performance when used in hydrocarbon

Description

CATALYST OF CEOI-ITA OUE CONTAINS METAL, ITS PREPARATION AND USE FOR CONVERSION OF HYDROCARBONS Field of the Invention This invention relates to a method of preparing zeolite catalysts linked to zeolite having improved hydrogenation / dehydrogenation metal dispersion, the catalyst itself, and the use of the catalyst in hydrocarbon conversion processes. Background of the Invention The crystalline, microporous molecular sieves, both natural and synthetic, have been shown to have catalytic properties for various types of hydrocarbon conversion processes. In addition, the crystalline, microporous molecular sieves have been used as adsorbents and catalyst carriers for various types of hydrocarbon conversion processes and other applications. These molecular sieves are ordered, porous, crystalline materials that have a defined crystalline structure, as determined by X-ray diffraction, within which there is a large number of smaller cavities that can be connected by several channels or even smaller pores. . The dimensions of these channels or pores are such as to allow the adsorption of molecules with certain dimensions, while rejecting those of larger dimensions. The interstitial spaces or channels formed by the crystalline lattice allow molecular sieves such as crystalline silicates, crystalline aluminosilicates, crystalline siliucoalumino phosphates, and crystalline aluminophosphates to be used as molecular sieves in separation processes and catalysts and catalyst supports in a wide variety of hydrocarbon conversion processes. The zeolites comprise a lattice of silica and optionally alumina, combined with interchangeable cations such as alkali metal or alkaline earth metal ions. Although the term "zeolites" includes materials containing silica and optionally alumina, it is recognized that the portions of silica and alumina can be replaced in whole or in part with other oxides. For example, germanium oxide, tin oxide, phosphorus oxide, and mixtures thereof, can replace the silica portion. Boron oxide, iron oxide, gallium oxide, indium oxide, and their mixtures, can replace the alumina portion. Accordingly, the terms "zeolite", "zeolites" and "zeolite material", as used herein, will not only mean silicon-containing materials, and optionally aluminum atoms in their crystalline lattice structure, but also materials that they contain suitable replacement atoms for such silicon and aluminum, such as galosilicates, silicoaluminum-phosphates (SAPO), and aluminophosphates (ALPO). The term "aluminosilicate zeolite", as used herein, will mean materials that consist essentially of silicon and aluminum atoms in their crystalline lattice structure. Zeolites such as ZSM-5, which have been combined with a Group VIII metal, have been used in the past as catalysts for hydrocarbon conversion. For example, U.S. Patent 3,856,872 discloses a zeolite that preferably contains a binder such as alumina that has been loaded with platinum by impregnation or ion exchange. A problem associated with zeolite catalysts that have been charged with metals by impregnation or ion exchange is that the metal may not disperse well. If the metal is not well dispersed, selectivity, activity and / or preservation of the zeolite catalyst activity may be adversely affected. U.S. Patent 4,312,790 discloses another method of loading platinum into an alumina-bound zeolite. The method involves adding the noble metal to the zeolite after crystallization of the zeolite, but before calcination. Catalysts prepared by this method have not been commercially useful because, as reported in the United States patent 4, 683,214, the use of the method has resulted in catalysts with poor platinum dispersion and large platinum crystallites. Patent document EP-A-0 284 206 involves a zeolite L catalyst without binder containing charged catalytically active metals by ion exchange. Patent document GB-A-1 511 892 involves adsorbents of crystalline aluminosilicate form prepared by converting a mixture containing crystalline aluminosilicate, silica, water, alumina and Na20 into shape products. The document mentions that the crystalline aluminosilicate can be exchanged in ions with a metal of groups II to VIII before including the crystalline aluminosilicate in the mixture. WO-A-96/16004 discloses zeolite bound to zeolite containing catalytically active metal charged by ion exchange. The synthetic zeolites are usually prepared by the crystallization of zeolites from one. mixture of supersaturated synthesis. The resulting crystalline product is then dried and calcined to produce a zeolite powder. Although zeolite powder has good adsorption properties, its practical applications are severely limited because it is difficult to operate fixed beds with zeolite powder. Therefore, before using the powder in commercial processes, the zeolite crystals are usually bound. The zeolite powder is typically bound to form an aggregate of zeolite such as a pill, sphere or extrudate. The extrudate is usually formed by extruding the zeolite in the presence of a non-zeolitic binder and drying and calcining the resulting extrudate. The binder materials used are resistant to temperatures and other conditions, for example mechanical attrition, which occur in various hydrocarbon conversion processes. Examples of binder materials include amorphous materials such as alumina, silica, titania and various types of clays. It is generally necessary that the zeolite be resistant to mechanical attrition, ie the formation of fine particles which are small particles, for example particles having a size of less than 20 microns. Although such bound zeolite aggregates have much better mechanical strength than the zeolite powder, when such bound zeolite is used for conversion of aromatics, the performance of the catalyst, for example activity, selectivity, maintenance of the activity, or combinations thereof, can be reduced due to the binder. For example, since the amorphous binder is typically present in an amount of up to about 50% by weight of zeolite, the binder dilutes the adsorption properties of the zeolite aggregate. In addition, since the bound zeolite is prepared by extruding or otherwise forming the zeolite with the binder and subsequently drying and calcining the extrudate, the amorphous binder can penetrate the pores or otherwise block access to the pores of the zeolite, or reduce the rate of transfer of mass to the pores of the zeolite, which can reduce the effectiveness of the zeolite when it is used in hydrocarbon conversion processes. Furthermore, when such bound zeolite is used in aromatic conversion processes, the binder may affect the chemical reactions that are taking place within the zeolite and may also itself catalyze undesirable reactions which may result in the formation of undesirable products. In certain hydrocarbon conversion processes involving dehydrogenation and dehydrocyclization reactions, it is desirable that the zeolite catalyst used in the process be effective for metal catalyzed reactions, for example conversion of paraffins to aromatics. In order for the catalyst to be effective for metal catalyzed reactions, a catalytically active metal is usually included in the catalyst. The catalytically active metal must be uniformly dispersed. If the metal is not dispersed evenly, activity, selectivity and / or preservation of catalyst activity can be negatively affected. Accordingly, it would be desirable to produce zeolite catalysts having hydrogenation / dehydrogenation metals uniformly dispersed and not containing substantial amounts of non-zeolitic binder. SUMMARY OF THE INVENTION In accordance with the present invention, a zeolite catalyst linked to zeolite and a process for preparing the zeolite catalyst bound to zeolite are provided. The catalyst comprises first crystals of a first zeolite, and a hydrogenation / dehydrogenation metal. The process is carried out by converting the silica binder from a silica bonded extrudate which also contains the first crystals of the first zeolite and the hydrogenation / dehydrogenation metal, into the second zeolite. In another embodiment, the present invention provides a process for the conversion of hydrocarbon feeds using the zeolite catalyst linked to zeolite in a process or a combination of processes employing a hydrogenation / dehydrogenation metal, such as a metal of the group VIII. Examples of such processes include hydrogenation, dehydrogenation, dehydrocyclization, isomerization, disintegration (cracking), dewaxing, reformation, alkyl-aromatic conversion, oxidation, synthesis gas conversion, hydroformylation, dimerization, polymerization, and alcohol conversion. . When used in processes such as naphtha reformation and xylene isomerization, the zeolite catalyst bound to zeolite exhibits a high hydrogenation / dehydrogenation activity which results in the production of desired products, while at the same time exhibiting a reduced activity of disintegration that is undesirable in these processes. Brief Description of the Drawings Figure 1 shows an electron microphotograph of the catalyst prepared in Example 1.1. Figure 2 shows an electron microphotograph of the catalyst prepared in Example l.II.

Detailed Description of the Invention The zeolite catalyst linked to zeolite comprises first crystals of a first -ceolite, a binder comprising second crystals of a second zeolite, and a hydrogenation / dehydrogenation metal. In preparing the zeolite catalyst bound to zeolite, the hydrogenation / dehydrogenation metal is present in the silica-bonded extrudate containing the first zeolite before converting the silica binder into the second zeolite. The resulting zeolite catalyst bound to zeolite has an improved dispersion of the hydrogenation / dehydrogenation metal. In addition, the use of second crystals of the second zeolite zeolite as a binder results in a catalyst that provides means for controlling undesirable reactions that take place on or near the outer surface of the first zeolite crystals and may have improved mass transfer of hydrocarbon molecules to and from the pores of the first zeolite. Unlike typical zeolite catalysts used in hydrocarbon conversion processes, which are normally bound with silica or alumina or other commonly used amorphous binders, to improve the mechanical strength of the zeolite, the zeolite catalyst of the present invention generally does not contain significant amounts of non-zeolitic binders. Preferably, the zeolite catalyst bound to zeolite contains less than 10% by weight based on the total weight of the first and second zeolites, of the non-zeolitic binder, more preferably it contains less than 5% by weight, and with the greatest Preferably, the catalyst is substantially free of non-zeolitic binder. Preferably, the second crystals of zeolite bind the first crystals of zeolite by adhering to the surface of the first crystals of zeolite, thereby forming a matrix or bridge structure which also holds together the particles of the first crystals. More preferably, the second zeolite particles bind the first zeolite by interdevelopment to form a partial coating or coating on the larger crystals of the first zeolite and, most preferably, the second zeolite crystals link the first crystals of zeolite by inter-development to form an over-development resistant to attrition on the first zeolite crystals. Although the invention is not intended to be limited by any theory of operation, it is believed that in addition to the improved metal dispersion, another advantage of the zeolite catalyst linked to zeolite of the present invention is obtained by the fact that the second crystals of zeolite control the accessibility of the acid sites on the external surfaces of the first zeolite to the reagents. As the acid sites that exist on the outer surface of a zeolite catalyst are not selective in form, these acidic sites can adversely affect reagents entering the pores of the zeolite and products leaving the pores of the zeolite. In line with this belief, since the acidity and the type of structure of the second zeolite can be carefully selected, the second zeolite does not significantly affect negatively the reagents that come out of the pores of the first zeolite, which can occur with conventionally bound zeolite catalysts and can beneficially affect reagents leaving the pores of the first zeolite. Furthermore, since the second zeolite is not amorphous but instead is a molecular sieve, the hydrocarbons have increased access to the pores of the first zeolite during hydrocarbon conversion processes. Regardless of the theories proposed, the zeolite catalyst linked to zeolite, when used in catalytic processes, has one or more of the improved properties disclosed herein. The terms "acidity", "lower acidity" and "high acidity", as applied to zeolite, are known to those skilled in the art. The acidulated properties of zeolite are well known. However, with respect to the present invention, a distinction must be made between acid intensity and acid site density. The acid sites of a zeolite can be a Bronstead acid or a Lewis acid. The density of the acid sites and the number of acid sites are important to determine the acidity of the zeolite. The factors that directly influence the acid intensity are (i) the chemical composition of the zeolite framework, ie the relative concentration and type of tetrahedron atoms, (ii) the concentration of the extra-framework cations and the species extra-framework resulting, (iii) the local structure of the zeolite, for example, the pore size and location, within the crystal and at or near the surface of the zeolite, and (iv) the pre-treatment and the presence of co-adsorbed molecules. The magnitude of the acidity is related to the degree of isomorphic substitution provided; however, such acidity is limited to the loss of acid sites for a pure SiO2 composition. As used herein, the terms "acidity", "lower acidity" and "higher acidity" refer to the concentration of acidic sites, regardless of the intensity of such acidic sites, which can be measured by adsorption with ammonia. First and second zeolites suitable for use in the zeolite-bound zeolite catalyst of the present invention include large pore size zeolites, intermediate pore size zeolites, and small pore size zeolites. These zeolites are described in "Atlas of Zeolite Structure Types", W.H. Meier and D.H. Olson, editors, Butterworth-Heineman, third edition, 1992, which is incorporated herein by reference. A large pore zeolite generally has a pore size greater than about 7 A and includes, for example, zeolites structure type LTL, VFI, MAZ, MEI, FAU, EMT, OFF, BEA and MOR (IUPAC Ceolite Nomenclature Commission ). Examples of large pore zeolites include, for example, mazzite, offerite, zeolite L, VPI-5, zeolite Y, zeolite X, omega, beta, ZSM-3, ZSM-4, ZSM-18, and ZSM-20. A zeolite of intermediate pore size generally has a pore size of about 5 A to about 7 A and includes, for example, zeolites with structure type MFI, MFS, MEL, MTW, EUO, MTT, HEU, FER, and TON (IUPAC Ceolite Nomenclature Commission). Examples of intermediate size zeolites include ZSM-5, ZSM-12, ZSM-22, ZSM-23, ZSM-34, ZSM-35, ZSM-38, ZSM-48, ZSM-50, silicalite and silicalite 2. A zeolite of small pore size generally has a pore size of about 3 A to about 5.0 A and includes, for example, zeolites with structure type CHA, ERI, KFI, LEV and LTA (IUPAC Ceolite Nomenclature Commission). Examples of small size zeolites include ZK-4, SAPO-24, SAPO-35, ZK-14, SAPO-42, ZK-21, ZK-22, ZK-5, ZK-20, zeolite A, erionite, chabasite, zeolite T, gemlinite, ALPO-17 and clinoptilolite. Generally, the first and second zeolites of the zeolite catalyst bound to zeolite comprise compositions having the following molar ratio: X203: (n) Y02, wherein X is a trivalent element such as titanium, boron, aluminum, iron and / or gallium, And it is a tetravalent element such as silicon, tin and / or germanium; and n has a value of at least 1, said value being dependent on the particular type of zeolite and the trivalent element present in the zeolite.

When any of the zeolites has an intermediate pore size, the zeolite usually comprises a composition having the following molar ratio: X203: (n) Y02, where X is a trivalent element such as aluminum, boron, titanium and / or gallium, and it is a tetravalent element such as silicon, tin and / or germanium; and n has a value greater than 10, said value being dependent on the particular type of zeolite and the particular trivalent element present in the zeolite. When the first or the second zeolite has an MFI structure, n is preferably greater than 10. As is known to those skilled in the art, the acidity of a zeolite can be reduced using many techniques such as dealumination and water vapor formation. . In addition, the acidity of a zeolite depends on the shape of the zeolite, the hydrogen form having the highest acidity and other forms of the zeolite, such as the sodium form, having lower acidity than the acid form. Accordingly, the molar ratios of silica to alumina and silica to galia disclosed herein will not only include zeolites having the molar ratios disclosed, but will also include zeolites that do not have the molar ratios disclosed but have equivalent catalytic activity. When the first zeolite is a zeolite of gallium silicate intermediate pore size, the zeolite usually comprises a composition having the following molar ratio: Ga203: ySi02, where y is between about 10 and about 1,000. The framework of the zeolite may contain only gallium and silicon atoms or may also contain a combination of gallium, aluminum and silicon. When the first zeolite is a gallium silicate zeolite with MFI type structure, the second zeolite will preferably be a zeolite of intermediate pore size having a silica to gallium molar ratio greater than 100. The second zeolite may also have higher molar ratios from silica to galia, for example greater than 200, 500, 1,000, etc. When the first zeolite in the zeolite catalyst bound to zeolite is an aluminosilicate zeolite, the molar ratio of silica to alumina will usually depend on the type of structure of the first zeolite and the particular hydrocarbon process in which the catalyst is used and So much is not limited to any particular relationship. However, generally, and depending on the type of structure of the zeolite, the first zeolite will have a molar ratio of silica to alumina of at least 2: 1 and in some cases from 4: 1 to about 7: 1. For several zeolites, the molar ratio of silica to alumina will be in the range of about 10: 1 to about 1,000: 1. In applications such as when the catalyst is used in acid catalyzed reactions, for example the isomerization of a feed stream containing xylenes and ethylbenzene, the first zeolite will be acidic and preferably, especially when it is an intermediate pore size zeolite. , will have higher molar ratios of silica to alumina, for example 70: 1 to around 700: 1. If the catalyst is used in hydrocarbon conversion processes where acid catalyzed reactions are not desired, for example, reformation of zeolite L, the first zeolite will preferably exhibit reduced acid activity and, more preferably, exhibit little or no acid activity. For these types of processes, the acid activity can be reduced by using higher molar ratios of silica to alumina, by ion exchange or by other techniques known to those skilled in the art. The type of structure of the first zeolite will depend on the particular hydrocarbon process in which the zeolite catalyst system is used. For example, if the catalyst is used for reforming naphtha to aromatics, the type of zeolite will preferably be LTL (eg, zeolite L). If the catalyst is to be used for xylene isomerization, the first zeolite will preferably be a zeolite of intermediate pore size, such as an MFI type structure (eg, ZSM-5). If the catalyst is used for decay (cracking) of paraffins, the preferred pore size and structure type will depend on the size of the molecules to be disintegrated and the desired product. The selection of the type of structure for the hydrocarbon conversion processes is known to the technicians in the matter. When the first zeolite is an LTL type structure, the zeolite is preferably an aluminosilicate zeolite having a composition (expressed in terms of molar ratios of the constituent oxides in anhydrous form) of: (0.9-1.3) M2 / n0: A1203: xSi02, where M is a valence cation n, x is from 4 to 7.5, preferably 5 to 7.5. When the zeolite catalyst bound to zeolite is used for the isomerization of a feed stream containing alkyl-aromatic hydrocarbons, the first zeolite is preferably an aluminosilicate zeolite or a gallium silicate zeolite and the zeolite will usually have a molar ratio silica to alumina from 70: 1 to 700: 1 or a silica to gallium molar ratio of 24 to 500. The term "average particle size", as used herein, means the arithmetic mean of the diameter distribution of crystals on a volume basis. The average particle size of the crystals of the first zeolite is preferably from about 0.1 to about 15 microns. In some applications, the average particle size will preferably be from about 1 to about 6 microns. In other applications, such as the disintegration of hydrocarbons, the average preferred particle size is smaller, for example from about 0.1 to about 3.0 microns.

The type of structure of the second zeolite can be the same or it can be different from the first zeolite. The type of structure of the second zeolite will depend on the intended use of the zeolite catalyst linked to zeolite. For example, if the catalyst system is to be designed to be a bifunctional catalyst, the first and second zeolites can be selected and designed to perform the desired reactions. When the second zeolite is aluminosilicate zeolite, the mole ratio of silica to alumina-of the second zeolite will usually depend on the type of structure of the second zeolite and the particular hydrocarbon process in which the catalyst is used, and therefore is not limited to no particular relationship. However, generally, and depending on the type of structure of the zeolite, the ratio of silica to alumina will be at least 2: 1 to more than 1,000. In certain applications, it is desirable that the second zeolite have reduced acidity or even substantially no acidity. In those applications when the zeolite is a zeolite of intermediate pore size, such as ZSM-5, the second zeolite will usually have a molar ratio of silica to alumina of 200: 1 or greater, for example 300: 1, 500: 1, 1,000: 1, etc. In certain applications, the second zeolite will be a silicalite, ie an MFI-like structure substantially free of alumina, or silicalite 2, ie a MEL-like structure substantially free of alumina. The pore size of the second zeolite will preferably be a pore size that does not adversely restrict access of the desired molecules of the hydrocarbon feed stream to the pores of the first zeolite. For example, when the material of the feed stream to be converted by the first zeolite has a size of 5 to 6.8 A, the second zeolite will preferably be a large pore zeolite or a medium pore zeolite. The second zeolite is usually present in the catalyst system in an amount in the range of about 10 to 60% by weight based on the weight of the first zeolite, and the amount of the second zeolite present will usually depend on the hydrocarbon process in which the catalyst is used. More preferably, the amount of second zeolite present is from about 20 to about 50% by weight. The second crystals of zeolite will usually have a smaller size than the first zeolite particles and preferably have an average particle size of less than 1 miera, for example from about 0.1 to about 0.5 microns. The second crystals of zeolite agglutinate the first crystals of zeolite and preferably inter-develop and form an over-development that coats or partially coats the first zeolite. Preferably, the coating is resistant to attrition. The zeolite bound to zeolite may also contain a hydrogenation / dehydrogenation component. The reference to metal or hydrogenation / dehydrogenation metals is intended to encompass such metals or metals in the elemental state (ie zero valence) or in some other catalytically active form such as an oxide, sulfide, halide, carboxylate and the like. Those skilled in the art are aware of such metals, and include, for example, one or more metals of groups IIIA, IVA, VA, VIA, VIIA, VIII, IB, IIB, IIIB, IVB and VB of the Periodic Table of the Elements . Examples of suitable metals include Group VIII metals (ie, Pt, Pd, Ir, Rh, Os, Ru, Ni, Co and Fe), metals of the IVA group (ie, Sn and Pb), metals of the VB group ( ie, Sb and Bi), and metals of group VIIB (ie, Mn, Te and Re). Sometimes precious metals are preferred (ie, Pt, Pd, Ir, Rh, Os and Ru). The amount of metal present in the zeolite catalyst bound to zeolite will be an effective amount which will generally be from about 0.001 to about 10% by weight, and preferably 0.05 to 3.0% by weight. The amount will vary with the nature of the metal, requiring less of highly active metals, particularly platinum, than less active metals. In preparing the zeolite catalyst bound to zeolite containing the hydrogenation / dehydrogenation metal, the metal will be present in a silica-bonded aggregate containing the first zeolite before converting the silica binder into the second zeolite of the zeolite catalyst bound to the zeolite. zeolite The addition of the metal to the silica bonded aggregate can be achieved at any stage before converting the silica binder into the second zeolite as before, during or after the formation of the silica bonded aggregate. For example, the zeolite catalyst linked to zeolite is preferably made using the following steps: 1. Prepare the first zeolite using known methods. 2. Form an extruded mass containing silica and the first zeolite. 3. Extrude the mass to form an aggregate linked to silica. 4. Calcite the aggregate bound to silica. 5. Aging the silica-bound aggregate in an appropriate aqueous solution. 6. Convert the silica binder from the silica bonded aggregate into the second zeolite by aging. The addition of the metal to the silica bonded aggregate can take place at any time before step 6, for example during steps 1-5. For example, the metal can be incorporated with the first zeolite before the start of step 2 by co-crystallization of the metal and the first zeolite or by loading the metal onto the first zeolite by techniques such as ion exchange or impregnation. The metal can also be added during the formation of the extruded mass, after the formation of the silica-bonded aggregate, before calcination, after calcination, or during the aging of the silica-bonded aggregate. In a preferred embodiment, the metal is added during step 2 by including the metal in the extrudable mass. After converting the silica binder into the second zeolite, the metal may be present on the surface of either or both of the zeolites and may also be present in the intra-crystalline matrix of either or both of the zeolites. The catalysts produced by the method of the invention offer at least one of the following advantages: improved metal dispersion, reduced disintegration activity while maintaining high hydrogenation / dehydrogenation activity, or combinations thereof. The zeolite catalyst bound to zeolite containing the hydrogenation / dehydrogenation metal is preferably prepared by a three-step process. The first step involves the synthesis of the first intermediate pore size zeolite. The processes for preparing the first zeolite are known to those skilled in the art. For example, with respect to the preparation of an aluminosilicate zeolite or a gallium silicate zeolite having an MFI type structure, a process comprises preparing a solution containing tetrapropyl ammonium hydroxide or bromide, alkali metal oxide, aluminum oxide or a gallium oxide, a silicon oxide and water, heating the reaction mixture at a temperature of 80 to 200 ° C for a period of about four hours to eight days. The resulting gel forms solid crystal particles that are separated from the reaction medium, washed with water, and dried. The resulting product can be calcined in air at temperatures of 400-550 ° C for a period of 10-40 hours, to remove tetrapropylammonium cations (TPA). In the second step, a zeolite bound to silica is prepared by mixing a mixture comprising the first crystals of zeolite, a silica gel or sol, water, and the hydrogenation / dehydrogenation metal or a metal-containing compound, and optionally a extrusion coadjuvant, until a homogeneous composition is developed in the form of an extrudable paste. The silica used in the preparation of zeolite aggregate bound to zeolite is preferably a silica sol and may contain various amounts of trivalent elements, for example aluminum or gallium. The amount of silica used is such that the content of the zeolite in the dry extrudate in this step will vary from about 40 to 90% by weight, more preferably from about 50 to 80% by weight, the remainder being mainly silica, for example about 20 to 50% by weight of silica. The resulting paste is then molded, for example extruded, and cut into small filaments, for example 2 mm diameter extrudates, which can be dried at 100-150 ° C for a period of 4 to 12 hours and then calcined in air at a temperature of about 400 to 550 ° C for a period of about 1 to 10 hours.

Optionally, the aggregate bonded to silica can be made into extremely small particles that have application in fluid bed processes such as catalytic disintegration (cracking). This preferably involves mixing the zeolite with a matrix solution containing silica so that an aqueous solution of zeolite and silica binder is formed which can be spray dried to result in small fluidizable particles of silica-bonded aggregate. The methods for preparing such aggregate particles are known to those skilled in the art. An example of such a procedure is described by Scherzer (Octane-Enhancing Zeolitic FCC Catalysts, Julius Scherzer, Marcel Dekker, Inc., New York, 1990). The fluidizable particles of silica-bonded aggregate, such as the silica-bonded extrudates described above, would then be subjected to the final step described below to convert the silica binder into a second zeolite. The final step in the three-step catalyst preparation process is the conversion of the silica present in the silica-bound zeolite into a second zeolite which binds the first crystals together. To prepare the second zeolite, the silica-bonded aggregate can be first aged in an appropriate aqueous solution at an elevated temperature. Next, the content of the solution and the temperature at which the aggregate is aged should be selected to convert the amorphous silica binder into the desired second zeolite. The second newly formed zeolite is produced as crystals. The crystals can develop on and / or adhere to the first crystals of zeolite, and can also be produced in the form of new inter-developed crystals, which are generally much smaller than the first crystals, for example, of sub-size. -micras. These newly formed crystals can develop together and interconnect. The nature of the zeolite formed in the secondary synthesis conversion of silica to zeolite can vary as a function of the composition of the secondary synthesis solution and the conditions of synthetic aging. The secondary synthesis solution is preferably an aqueous ionic solution containing a sufficient hydroxy ion source to convert the silica into the desired zeolite. However, it is important that the aging solution be of a composition such that it does not cause the silica present in the bound zeolite extrudate to dissolve outside the extrudate. In a preferred embodiment of the invention, the aqueous ionic solution in which the silica-bonded aggregate is aged contains a source of hydroxy ions (preferably NaOH). When manufacturing a zeolite with an MFI type structure, the initial molar ratio of OH to SiO2 is preferably at a level of up to about 1.2, with a greater preference of about 0.05 to 1.2, and with the greater preference of about 0.07 to 0.15. This treatment causes the silica binder to be substantially converted into a zeolite with MFI type structure, but of lower acidity, as reflected by having a considerably higher silica to alumina ratio. The solution also contains a template (e.g., a tetraalkyl ammonium ion source for zeolites with MFI type structure) and may optionally include an alumina source and a source of Na + ions. The ratio of silica to alumina of the converted binder is thus controlled by controlling the composition of the aqueous solution. It is important that the aging solution has a pH that is not too alkaline. This can be achieved, when a bound zeolite of the MFI type structure is produced, using a solution having an initial molar ratio of OH: SiO2 of 0.05 to 1.2. Generally, ratios of 0.07 to 0.15 are preferred. The aging of the zeolite extrudate in the aging solution is preferably conducted at elevated temperatures, generally in the range of about 95 to 200 ° C, more preferably in the range of about 130 to 170 ° C, most preferably in the range of about 145 to 155 ° C. The aging time may vary from about 20 to 140 hours, more preferably from about 60 to 140 hours, most preferably from about 70 to 80 hours. After aging, the zeolite bound to zeolite is separated from the solution, washed, dried and calcined.

The first and second zeolites of the zeolite catalyst of the present invention can be further ion exchanged, as is known in the art, either to replace at least in part the original alkali metal present in the zeolite with a different cation, for example from group IB to VIII of the Periodic Table of the Elements, or to provide a more acid form of the zeolites by exchange of the alkali metal with intermediate ammonium, followed by calcination of the ammonium form to provide the acid hydrogen form. The acid form can be easily prepared by ion exchange using a suitable acid reagent such as ammonium nitrate. The zeolite catalyst can then be calcined at a temperature of 400-550 ° C for a period of 10-45 hours to remove ammonia and form the acid hydrogen form. The ion exchange is preferably conducted after the formation of the zeolite catalyst. The zeolite catalysts linked to zeolite of the present invention can be used in the processing of hydrocarbon feedstocks. The hydrocarbon feedstocks contain carbon compounds and can be from many different sources, such as virgin oil fractions, recycle oil fractions, shale sands oil, and in general can be any fluid containing carbon susceptible to reactions. Catalytic catalysts. Depending on the type of processing to which the hydrocarbon feed is subjected, the feed may contain metal or may be free of metals. Also, the feed may also have high or low nitrogen or sulfur impurities. The conversion of the hydrocarbon feeds can take place in any convenient way, for example in fluidized bed, moving bed, or fixed bed reactors, depending on the types of process desired. The zeolite catalyst bound to zeolite can be used as a catalyst for a variety of organic compound conversion processes, for example hydrocarbons, including hydrogenation, dehydrogenation, dehydrocyclization, isomerization, hydrodisintegration, deparaffination, reformation, alkyl-aromatic conversion, oxidation , reforming, converting synthesis gas, hydroformylation, dimerization, polymerization, alcohol conversion, etc. Catalytic conversion conditions for hydrogenation of feedstocks such as alkenes, dienes, polyenes, alkynes, cyclin, aromatics, oxygenates, etc., include a temperature between about 0 and about 1,000 ° F, preferably between about 80 and 900 ° F, a pressure of between about 10 and about 1,000 psia, preferably between about 20 and 200 psia, a hydrogen / feed molar ratio of between about 0.1 and 20, preferably between about 4 and 12, and an LHSV of between about 0.1 and 20, preferably between about 0.5 and 4. The dehydrogenation conditions, for processes such as the conversion of paraffins to the corresponding olefins, or ethylbenzene in styrene, optionally in the presence water vapor or inert gases such as nitrogen, include temperatures of about 400 to 1,800 ° F, preferably of about 650 to 1,000 ° F; partial pressures of the feedstock of about 10,000 to 15,000 psia, preferably about 2 to 20 psia, and an LHSV of about 0.1 to 100, preferably between about 0.5 and 4. Dehydrocyclization conditions, for example for conversion of paraffins to aromatics (eg, octane to ethylbenzene or xylene), include temperatures of about 400 to 1,800 ° F, preferably of about 600 to 1,110 ° F; partial pressures of the feedstock of about 1 to 1,500 psia, preferably about 2 to 20 psia, and an LHSV of about 0.1 to 100, preferably between about 0.5 and 4. Isomerization of normal paraffins, with or without hydrogen, is conducted at a temperature of between about 212 and 500 ° F, preferably between about 400 and 900 ° F, an LHSV of between about 0.01 and 20, preferably between about 0.25 and 5. , and a molar ratio of hydrogen to hydrocarbon of between 0 and 5: 1. The conditions of catalytic conversion for disintegration, with or without hydrogen, include a temperature of between about 1,200 and about 100 ° F, a pressure of between about 25 and about 2,500 psia, a molar ratio of hydrogen / feed between about 0 and about 80, and an LHSV of between about 0.1 and about 10. The catalysts of the present invention are also useful for dewaxing operations. Similarly, the invention can be used in reforming catalysts or as part of a reforming catalyst. Deparaffination and reformation can be carried out in the presence or absence of hydrogen under conditions that include a temperature of about 500 to 1,100 ° F, preferably of about 800 to 950 ° F.; a pressure of 1.5 to 1.470 psia, and a WHSV of about 0.01 to about 100, preferably of about 0.1 to 10. In this way, hydrocarbon conversion processes that find particular application include the following: (A) The catalytic disintegration of a naphtha feed to produce light olefins. Exemplary reaction conditions include from about 500 to about 750 ° C, pressures from sub-atmospheric to atmospheric, generally varying up to about 10 atmospheres (gauge) and residence time (volume of catalyst feed rate) of around from 10 milliseconds to around 10 seconds.

(B) The catalytic disintegration of high molecular weight hydrocarbons to lower molecular weight hydrocarbons. Exemplary reaction conditions for catalytic disintegration include temperatures of about 400 to about 700 ° C, pressures of about 0.1 to about 30 atmospheres, and space hourly rates in weight of about 0.1 to about 100 hr "1. C) Isomerization of aromatic components (eg, xylene) of feedstock Exemplary reaction conditions for this include a temperature of from about 230 to about 510 ° C, a pressure of about 0.5 to about 50 atmospheres, a space velocity hourly in weight of about 0.1 to about 200, and a hydrogen / hydrocarbon molar ratio of about 0 to about 100. (D) The hydrodisintegration of heavy oil feed materials, cyclic materials, and others Hydrodegradation charging materials The zeolite catalyst system will contain an effective amount of at least one hydrogenation component of the type used in hydrodes-integration catalysts. (E) The conversion of light paraffins into olefins and / or aromatics. Exemplary reaction conditions include temperatures of about 425 to about 760 ° C and pressures of about 10 to about 2,000 psig. '(F) The conversion of light olefins in gasoline, distillates, and hydrocarbons of lubrication range. Exemplary reaction conditions include temperatures of about 175 to about 375 ° C and a pressure of about 100 to about 2,000 psig. (G) Hydro-disintegration in two stages to improve hydrocarbon streams having initial boiling points of more than about 200 ° C to special distillates and products with boiling range of gasoline or as feed for additional steps of fuel or product processing chemical The first step would be the zeolite catalyst comprising one or more catalytically active metals, for example a metal of group VIII, and the effluent from the first stage would be reacted in a second step using a second zeolite, for example beta zeolite, comprising one or more catalytically active substances, for example a metal of group VIII, as a catalyst. Exemplary reaction conditions include temperatures of about 315 to about 455 ° C, a pressure of about 400 to about 2,500 psig, hydrogen circulation of about 1,000 to about 10,000 SCF / barrel and a liquid hourly space (LHSV) of about 0.1 to 10. (H) A hydrodeintegration / dewaxing process in combination, in the presence of zeolite catalyst bound to zeolite comprising a hydrogenation component and a zeolite such as zeolite beta. Exemplary reaction conditions include temperatures of about 350 to about 400 ° C, pressures of about 1,400 to about 1,500 psig, LHSV of about 0.4 to about 0.6, and a hydrogen circulation of about 3,000 to about 5,000 SCF / barrel. (I) The reaction of alcohols with olefins to provide mixed ethers, for example the reaction of methanol with isobutene and / or isopentene to provide the methyl-t-butyl ether (MTBE) and / or the methyl t-amyl ether (TAME) . Exemplary conversion conditions include temperatures from about 20 to about 200 ° C, pressures from 2 to about 200 atmospheres, WHSV (grams of olefin per grams of zeolite hour) from about 0.1 to about 200 hr "1, and a mole ratio of alcohol to olefin feed of about 0.1 / 1 to about 5/1. (J) The conversion of naphtha (eg, C6-C10) and similar mixtures into highly aromatic mixtures. normal and slightly branched chain, preferably having a boiling range above about 40 ° C, and less than about 200 ° C, can be converted into products having a substantial higher octane aromatics content by contacting the hydrocarbon feedstock with the zeolite at a temperature in the range of about 400 to 600 ° C, preferably 480 to 550 ° C, at pressures that they vary from atmospheric to 40 bar, and LHSV ranging from 0.1 to 15. (K) The conversion of oxygenates, for example alcohols, such as methanol, or ethers, such as dimethyl ether, or mixtures thereof, into hydrocarbons including olefins and aromatics with reaction conditions that include a temperature of about 275 to about 600 ° C, a pressure of about 0.5 to about 50 atmospheres, and LHSV of about 0.1 to about 100. (L) Oligomerization of olefins straight and branched chain having from about 2 to about 5 carbon atoms. The oligomers which are the products of the process are medium to heavy olefins which are useful both for fuels, ie gasoline or a physical mixture of gasoline, and for chemical products. The oligomerization process is generally carried out by contacting the olefin feed material in a gas phase with a zeolite bound to zeolite at a temperature in the range of about 250 to about 800 ° C, a LHSV of about 0.2 to about 50, and a partial hydrocarbon pressure of around 0.1 to about 50 atmospheres. Temperatures below about 250 ° C can be used to oligomerize the feedstock when the feedstock is in the liquid phase when it contacts the zeolite catalyst bound to zeolite. In this way, when the olefin feedstock contacts the catalyst in the liquid phase, temperatures of about 10 to about 250 ° C can be used.

(M) The conversion of unsaturated C2 hydrocarbons (ethylene and / or acetylene) into aliphatic C6_12 aldehydes and conversion of said aldehydes to the corresponding C6_12 alcohols, acids or esters. (N) The conversion of alkyl-aromatic hydrocarbons, such as the dealkylation of ethylbenzene in benzene. (O) The saturation of olefins having from 2 to 20 carbon atoms. (P) The isomerization of ethylbenzene in xylenes. Exemplary conversion conditions include a temperature of 600 to 800 ° F, a pressure of 50 to about 500 psig, and an LHSV of about 1 to about 10. In general, the conditions of catalytic conversion on the zeolite catalyst of the invention independently and in combination include a temperature of about 100 to about 760 ° C, a pressure of about 0.1 to about 200 atmospheres (bars), a WHSV of about 0.08 to about 2,000 hr "1 Although many hydrocarbon conversion processes prefer that the second crystals of zeolite have lower acidity, some processes prefer that the second crystals of zeolite have higher acidity.The processes that find particular application using the zeolite catalyst linked to zeolite are those where two or more reactions are taking place within the zeolite catalyst system.The zeolite catalyst bound to zeolite would comprise two different it is zeolites, which are each designed separately to promote or inhibit different reactions. A process using such a catalyst benefits not only from the increased apparent activity of the catalyst, greater accessibility to the zeolite, and reduced non-selective surface acidity that are possible with zeolites bound to zeolite, but also from a catalyst system designed at the measure. The process of the present invention finds particular application for isomerizing one or more isomers of xylene in a C8 aromatic feed to obtain ortho, meta and para-xylene in a ratio approaching the equilibrium value while substantially converting ethylbenzene. In particular, xylene isomerization is used in conjunction with a separation process to manufacture para-xylene. For example, a portion of the para-xylene can be recovered in a stream of mixed C8 aromatics using processes known in the art, for example crystallization, adsorption, etc. The resulting stream is then reacted under xylene isomerization conditions to restore ortho, meta and para-xylenes to a close to equilibrium relationship. At the same time, it is also desirable that the ethylbenzene in the feed be converted with very little net loss of xylenes. The acidity of the first zeolite and the second zeolite of the zeolite catalyst bound to zeolite can be selected to balance the isomerization of xylene and the dealkylation of ethylbenzene while minimizing undesirable side reactions, for example ethylation of xylenes and transalkylation of ethylbenzene / ethylbenzene or ethylbenzene / xylene. The isomerization process is carried out by contacting the C8 aromatic stream containing one or more xylene or ethylbenzene isomers, or mixtures thereof, under isomerization conditions, with the zeolite catalyst bound to zeolite. The catalyst of the present invention is useful for saturating ethylene formed during dealkylation of ethylbenzene and offers the benefit of reduced aromatics saturation and the subsequent disintegration of naphthenes. Suitable isomerization conditions include a temperature in the range of 250 to 600 ° C, preferably 300 to 550 ° C, a pressure in the range of 0.5 to 50 absolute atmospheres, preferably 10 to 25 absolute atmospheres, and a space weight hourly speed (WHSV) from 0.1 to 100, preferably 0.5 to 50. Optionally, isomerization in the vapor phase is conducted in the presence of 0.1 to 30.0 moles of hydrogen per mole of alkylbenzene. If hydrogen is used, the catalyst should comprise 0.01 to 2.0% by weight of a hydrogenation / dehydrogenation component selected from group VIII of the Periodic Table, especially platinum, palladium or nickel. By metal component of group VIII is meant the metals and their compounds, such as oxides and sulfides. The zeolite catalysts linked to zeolite find particular application in reactions involving aromatization and / or dehydrogenation. They are particularly useful in a process for the dehydrocyclization and / or isomerization of acyclic hydrocarbons, where the hydrocarbons are contacted at a temperature of 370 to 600 ° C, preferably 430 to 550 ° C, with the zeolite catalyst. bound to zeolite, preferably zeolite L bound by zeolite L, preferably having at least 90% of the cations exchangeable as alkali metal ions and incorporating at least one metal of group VIII having dehydrogenation activity, so as to convert at least part of the acyclic hydrocarbons in aromatic hydrocarbons. The aliphatic hydrocarbons can be straight or branched chain acyclic hydrocarbons, and particularly paraffins such as hexane, although mixtures of hydrocarbons such as paraffin fractions containing a range of alkanes, possibly with minor amounts of other hydrocarbons, can also be used. Cycloaliphatic hydrocarbon such as methylcyclopentane can also be used. In a preferred embodiment, the feed to a process for preparing aromatic hydrocarbons and particularly benzene comprises hexanes. The temperature of the catalytic reaction can be from 370 to 600 ° C, preferably 430 to 550 ° C, and pressures in excess of atmospheric, for example up to 2,000 KPa, more preferably 500 to 1,000 KPa, are preferably used. Hydrogen is usually used in the formation of aromatic hydrocarbons, preferably with a hydrogen to feed ratio of less than 10. The following examples illustrate the invention: Example 1 Preparation of Galium Silicate Catalyst Type MFI Linked to Zeolite I. Catalyst A - Platinum Loaded During the Synthesis Gallium silicate crystals with MFI structure were prepared, as follows: The ingredients of solution A were dissolved by boiling until a clear solution was obtained. Solution A was then cooled to room temperature and the water loss from boiling was corrected. Solution B was poured into a 2 liter glass flask. Solution C was poured into the contents of the flask and mixed. Solution D was then poured into the contents of the flask and the contents of the flask was mixed. The contents of the flask were poured into a 2 liter stainless steel autoclave. Rinse water was used to rinse the flask and added to the autoclave. Solution A was added to the autoclave. The content of the autoclave was mixed around 20 minutes. A pourable, soft gel was obtained. The gel had the following composition, expressed in moles of pure oxide: 0.45 Na2O / 0.90 TPA Br / 0.125 Ga2O3 / 10 Si02 / 147 H20 The gel contained 1.0 ppm by weight of colloidal silica-lita seeds. The autoclave was placed in an oven and heated to 150 ° C for 2 hours and maintained at 150 ° C for 48 hours. The product was removed from the autoclave and divided into three portions. Each portion was washed seven times with about 600 g of water. The product was dried overnight at 120 ° C. The recovered amount of product was 333.70 grams. The product was calcined in air at 475 ° C for 48 hours. The characteristics of the calcined product were the following: XRD: MFI pure SEM: - spherical crystals of 4 microns of Elemental size: Si02 / Ga203 = 80 A portion of the calcined product was formed in 2 mm extrudates linked to silica, as follows: The components were mixed in a food mixer in the order shown. After adding the extrusion coadjuvant for about 7 minutes, a thick and soft paste was obtained. The paste was extruded in 2 mm extrudates and dried at room temperature for 3 hours. The extrudates were broken into smaller pieces of 5 mm and dried in an oven at 120 ° C for 16 hours. The dry extrudates were calcined at 490 ° C for 8 hours in air. The composition of the extrudate bonded to calcined silica was: Silica binder: 30.1% by weight MFI: 69.4% by weight Platinum: 0.5% by weight The silica bonded extrudates were converted to zeolite bound to zeolite, as follows: Solutions A and B were poured into a one liter autoclave and mixed. Finally, 70.0 g of the silica bonded extrudates were added to the autoclave. The molar composition of the synthesis mixture was: 0.48 Na2O / 1.00 TPABr / 10 Si02 / 149 H20 The autoclave was placed in an oven. The oven was heated from room temperature to 150 ° C in two hours and kept at this temperature for 80 hours. The resulting product was washed at 60 ° C four times with 1,700 ml of water. The conductivity of the last wash water was 49 μS / cm. The extrudates were dried at 120 ° C and calcined in air at 490 ° C for 16 hours. The product was analyzed by XRD and SEM with the following results: XRD: excellent crystallinity SEM: crystals of 4 microns in size, coated with crystals of smaller size. There was no visible amorphous silica. Elemental: core crystals: Si02 / Ga203 = 80 binder crystals = silicalite core crystals = 70% by weight platinum = 0.5% by weight The platinum distribution and the platinum particle size were determined by qualitatively examining a sample of the product by transmission electron microscopy (TEM), using a Philips CM12 TEM. Figure 1 represents an electron microphotograph of catalyst A. The images in the microphotograph indicate that the platinum was well distributed. The largest proportion of platinum had a particle size of 5 to 10 nm. II. Catalyst B - Platinum Loaded by Pore Filling A portion of the calcined MFI-type gallium silicate used to prepare catalyst A was formed in 2-mm silica-bonded extrudates, as follows: The above components were mixed in a food mixer in the order shown. After adding the extrusion coadjuvant and mixing for about 14 minutes, a thick and soft paste was obtained. The paste was extruded in 2 mm extrudates. The extrudates were dried at 150 ° C for 7 hours and then calcined in air at 510 ° C for 8 hours. Composition of silica-bonded calcined extrudates: MFI: 70.0% by weight Si02 binder: 30.0% by weight The silica bonded extrudates were converted to zeolite bound to zeolite, as follows: Solutions A and B were poured into a 300 ml stainless steel autoclave and mixed. Finally, 125.0 g of the MFI extrudates bonded to silica were added to the autoclave. The molar composition of the synthesis mixture is: 0.48 Na2O / 0.99 TPA Br / SiO2 / 148 H20 In this mixture, the silica is present as the binder in the extrudate. The autoclave was placed in an oven at room temperature, heated to 150 ° C within 2 hours, and maintained at 150 ° C for 72 hours. The resulting product was washed at 60 ° C with seven 2,000 ml portions of water. The conductivity of the last water wash was 25 μS / cm. The product was dried at 150 ° C and calcined in air at 500 ° C for 16 hours. The resulting product was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), with the following results: XRD: excellent crystallinity SEM: - MFI crystals of 4 microns, coated with smaller crystals. There was no visible amorphous silica. Elemental: core crystals: Si02 / Ga203 = 80 crystals of binder = silicalite core crystals = 70% by weight binder crystals ^ = 30% by weight An amount of 0.31% by weight of platinum was loaded into the catalyst (with base in the weight of the product). The process was carried out first by exchanging the catalyst at 65 ° C for a solution of NH4C1 IN. The exchanged catalyst was washed with water, dried, and then calcined at 530 ° C for 8 hours. Platinum loading was performed by the pore filling method, with an appropriate amount of Pt (NH3) 4Cl2 dissolved in water. After loading, the catalyst was dried and calcined at 480 ° C for 8 hours. Platinum distribution and platinum particle size were determined by qualitatively examining a sample of the product by transmission electron microscopy (TEM) using a Philips C12 TEM. Figure 2 represents an electron microphotograph of catalyst B. The images in the microphotograph indicate that the platinum particle size was predominantly 10-30 nm, and that platinum was not as well distributed as in catalyst A. Example 2 I Catalyst A - Xylene Isomerization / Combined Ethylene Benzene Isomerization Tests A series of combined ethylbenzene xylene / dealkylation isomerization tests were conducted using catalyst A, passing a xylene-rich feed through a bed reactor fixed. Catalyst A was pre-treated in H2 for two hours at 850 ° F and 250 psig. After the temperature had been reduced to 700 ° F, the catalyst was pre-sulphided until disrupted with about 500 ppm H2S in H2 at 250 psig. Subsequent oil tests were run under varying conditions. The conditions and results are shown in Table I below: * It is believed that negative values are due to minor variations in gas chromatography. The percentage of EB reacted was determined by the formula:% Conv. EB = 100 x (moles of EB in the feed - moles of EB in the product) / (moles of EB in the feed); the percentage loss of aromatic rings was determined by the formula: 100 x (moles of aromatics in the feed - moles of aromatics in the product) / (moles of aromatics in the feed). The loss of xylenes was determined by the formula: 100 x (moles of xylenes in the feed - moles of xylenes in the product) / (moles of xylenes in the feed) and the PX approach to equilibrium was determined by the formula: ( PX product / xylene feed PX / Xs) / (PX equilibrium / Xylene x PX / Xs) x 100. II. Catalyst B - Mixed Xylene Isomerization / Ethylbenzene Desalting Tests A series of combined xylene isomerization / dealkylation ethylbenzene tests were conducted using catalyst B, passing artificial feed through a fixed bed reactor. Catalyst B was pre-treated in H2 and pre-sulphided using the same procedure described in Example 2. Subsequent oil tests were run under varying conditions. The conditions and results are shown in Table II below: The data in the Table shows that at a comparable ethylbenzene conversion, ring loss and loss of xylene for catalyst A were considerably lower than for catalyst B. Both catalyst A and catalyst B were effective for isomerizing xylenes and convert ethylbenzene-no. Example 3 Preparation of KL Zeolite Linked by KL I Ceolite. Catalyst C - Platinum Loaded During Synthesis Crystals of aluminosilicate with LTL structure (KL zeolite) were prepared as follows: The ingredients of solution A were dissolved by boiling until a clear solution was obtained. Solution A was then cooled to room temperature and the water loss from boiling was corrected. Solution B was poured into a two liter stainless steel autoclave. Solution A was added to the autoclave. Rinse water was used to rinse the flask and added to the autoclave. The content of the autoclave was mixed until a smooth gel was obtained. The gel had the following composition, expressed in moles of pure oxide: 2.61 K2O / 1.0 Al2O3 / 10 Si02 / 158 H20 The full autoclave was pressurized at 65 psig with nitrogen gas and then heated 48 hours at a wall temperature of 79 ° C , without agitation. The autoclave was then stirred at 20 rpm and heated to a wall temperature of 150 ° C for 56 hours. Stirring was stopped and the autoclave was maintained at 150 ° C for 56 hours. The product was removed from the autoclave and washed three times with cold demineralized water. The pH of the first wash was 12.3, the pH of the second wash was 11.7, and the pH of the final wash was 11.4. The product was dried overnight at 150 ° C. The recovered amount of product was 310 g. X-ray diffraction analysis showed that the dried product was pure KL zeolite. A portion of the calcined product was formed in 2 mm silica bonded extrudates, as follows: The above components were mixed in a domestic mixer in the order shown. After adding metocel, a thickened and extrudable mass was obtained. The total mixing time was around 30 minutes. The mass was extruded in 2 mm extrudates, dried for 2 hours at room temperature, and then for 16 hours at 120 ° C, broken into 5 mm pieces, and then calcined at 490 ° C for 5 hours in air. The recovered amount of calcined product was 139.3 grams. Composition of calcined silica bonded extrudates: KL zeolite: 69.5% by weight Si02 binder: 29.9% by weight Platinum: 0.6% by weight KL zeolite extrudes bonded to silica were converted to KL zeolite bound by KL zeolite, as follows : A solution of potassium aluminate was prepared from the following (weight of chemicals in grams): KOH beads, purity 87.3% = 8.44 Al (OH) 3 powder, purity 98.5% = 6.40 H20 = 56.65 Alumina was dissolved by boiling until a clear solution was obtained. The solution was cooled to room temperature and corrected for water losses due to boiling. The aluminate solution was transferred quantitatively with 5.92 g of rinse water to a 300 ml stainless steel autoclave. Next, 50.0 grams of silica bonded extrudates containing 29.9% by weight of silica binder (0.20 g of adsorbed water in extrudates) were added to the autoclave content. The extrudates have been previously dried to remove adsorbed water. The composition of the mixture in the autoclave, corrected for the water content of the extrudates, was: 2.64 K20 / 1.62 Al2O3 / 10 Si02 / 148 H20 In this mixture, silica is present as the binder in the extrudate. The autoclave was heated to 175 ° C within 4.5 hours and maintained at this temperature for 65 hours. After this aging period, the autoclave was opened and the extrudates of the product were collected.

The extrudates were washed twice with 500 ml of water (temperature of 60 ° C) and then washed with 250 ml of water (temperature of 60 ° C). The pH of the final wash was 10.8, and the conductivity was 321 μS / cm. The extrudates were dried overnight at 120 ° C. The recovered amount of product was 55.8 grams. The extrudates of the product were characterized by XRD and SEM, with the following results: XRD: indicated the presence of zeolite L. SEM: showed the presence of crystals of zeolite L linked by smaller crystals newly formed. II. Catalyst D - Platinum Loaded by Pore Filling A portion of the calcined LTL type aluminosilicate structure (zeolite KL), used to prepare catalyst C, was formed in 2 mm silica bonded extrudates, as follows: The above components were mixed in a domestic mixer, in the order shown. After adding the methocel, a thickened and extrudable mass was obtained. The total mixing time was around 18 minutes. The mass was extruded in 2 mm extrudates, dried by 2 hours at room temperature, and then for 16 hours at 120 ° C, broken into pieces of 5 mm, and then calcined at 490 ° C by hours in air. The recovered amount of calcined product was 147.39 grams. Composition of silica bonded extrudates: KL zeolite: 69.95% by weight Si02 binder: 30.05% by weight The KL zeolite extrudes KL bound to silica were converted to KL zeolite bound by KL zeolite, as follows: An aluminate solution of KL was prepared as follows: potassium from the following chemicals (weight in grams): KOH beads, purity 87.3% = 9.25 Al (OH) 3 powder, purity 98.85% = 6.43 H20 = 56.99 Alumina was dissolved by boiling until a clear solution. The solution was cooled to room temperature and corrected for water losses due to boiling. The aluminate solution was transferred quantitatively with 5.94 grams of rinse water to a 300 ml stainless steel autoclave. Next, 50.0 grams of the silica-bonded extrudates containing 30 wt.% Silica clumping (0.47 grams per water adsorbed on extrudates) were added from the contents of the autoclave. The extrudates had been previously dried to remove the adsorbed water. The composition of the mixture in the autoclave, corrected for the water content of the extrudates, was: 2.88 K20 / 1.62 Al2O3 / 10 Si02 / 148 H20 In this mixture, the silica is present as a binder in the extrudate. The autoclave was heated to 175 ° C within 5.5 hours and maintained at this temperature for 65 hours. After this aging period, the autoclave was opened and the extrudates of the product were collected. The extrudates were washed with 2,000 ml of water for one hour (temperature of 60 ° C), and then washed with 1,000 ml of water for two hours (temperature of 60 ° C). The pH of the final wash water was 10.8, and the conductivity was 662 μS / cm. The extrudates were dried overnight at 120 ° C. The recovered amount of the product was 52.6 grams. The extrudates of the product were characterized by XRD and SEM, with the following results: XRD: indicated the presence of zeolite L. SEM: showed the presence of crystals of zeolite L linked by smaller crystals newly formed. An amount of 0.85% by weight of platinum (based on the weight of the catalyst) was charged to catalyst D by the filling method with an appropriate amount of Pt (NH3) 4Cl2, dissolved in water. After loading, the catalyst was dried. Example 4 Two separate aromatization tests were carried out using catalyst C and catalyst D. Before the start of the tests, each catalyst was subjected to a re-dispersion process and a reduction process, as follows: g of catalyst in a one-inch internal diameter quartz tube, which was placed in an electrically heated oven. For all described treatment steps, gas flowed through the tube and the catalyst sample, at a flow rate of 500 cc / minute. The catalyst was initially heated to 450 ° C with a gas composition of 10% by volume of 02 and 90% by volume of helium. The catalyst was maintained at 450 ° C for one hour. The temperature was then increased to 530 ° C and the gas composition changed to 20% by volume of 02, 2.2% by volume of H20 and 77.8% by volume of helium. The catalyst was exposed to these conditions for 67.5 hours. The catalyst was then cooled to 510 ° C in dry helium. At that point, the gas composition changed to 20% by volume of 02, 2.2% by volume of H20 and 77.8% by volume of helium. After 30 minutes, the composition was changed to 0.8% by volume of chlorine, 20% by volume of 02, 2.2% by volume of H20 and 77.0% by volume of helium. The catalyst was exposed to these conditions for 2 hours. The gas composition was then changed to 20% by volume of 02, 2.2% by volume of H20 and 77.8% by volume of helium. After two hours at these conditions, the 02 was removed and the residual oxygen was purged from the reactor with 2.2% by volume of H20 and 97.8% by volume of helium. At that point, hydrogen was introduced to change the gas composition to 20% by volume of H2, 2.2% by volume of H2O and 77.8% by volume of helium. The catalyst was reduced under these conditions for one hour. The gas composition was then changed to dry helium and the catalyst cooled to room temperature and removed from the reactor. The first aromatization test was carried out at a temperature of 950 ° F and a pressure of 1,000 psig with a mixed feed of C6 comprising 60% by weight and n-hexane, 30% by weight of 3-met-ilpentane, and 10% by weight of methylcyclopenta-no, at a WHSV of 6.0 w / w hr "1 and in the presence of hydrogen, the H2: hydrocarbon ratio being 6. The current time for catalyst C was 14.6 hours, and for catalyst D was 14.4 hours The results are indicated in Table 3 below: Table 3 The data in the Table shows that catalyst C had a benzene yield of 14% more than catalyst D, and had more than 50% fewer undesirable products of the feed stream that disintegrate at C ^ C ^,. The second aromatization test was carried out at a temperature of 860 ° F and a pressure of 100 psig with a light virgin naphtha feed at a WHSV of 1.0 w / w hr "1 and in the presence of hydrogen, the H2 ratio: hydrocarbon being 6. The current time for catalyst C was 16.5 hours and catalyst D was 16.3 hours The composition of the LVN feed comprised: The results of these tests are indicated in Table 4 below. Table 4 The data in the Table shows that catalyst C had more than 50% more net yield of A8 than catalyst D, and had more than 40% reduction in the disintegration of the feed stream at Q.x-Q.z. Catalyst D produced more benzene and toluene than catalyst C, but partially at the expense of more desirable xylenes.

Claims (29)

1. CLAIMS 1. A zeolite hydrocarbon conversion catalyst linked to zeolite, which does not contain significant amounts of non-zeolitic binder and contains at least one hydrogenation / dehydrogenation metal, comprising: (a) first crystals of a first zeolite, and (b) a binder comprising second crystals of a second zeolite; and (c) an effective amount of at least one hydrogenation / dehydrogenation metal; wherein the zeolite catalyst linked to zeolite is capable of being prepared by: (a) providing said first crystals of said first zeolite; (b) forming an aggregate linked to silica comprising at least a portion of said at least one hydrogenation / dehydrogenation metal and said first crystals of said first zeolite; and (c) converting into the second zeolite the silica binder of said silica-bonded aggregate, said portion of said at least one hydrogenation / dehydrogenation metal being added during the preparation of the catalyst after step (a).
2. 2. A method of preparing a zeolite catalyst linked to zeolite containing a hydrogenation / dehydrogenation metal that does not contain significant amounts of non-zeolitic binder and comprises first crystals of a first zeolite, second crystals of a second zeolite, and said metal of hydrogenation / dehydrogenation, which method comprises converting into the second zeolite the silica binder of a silica-bonded aggregate comprising the first crystals of a first zeolite and at least a portion of said at least one hydrogenation / dehydrogenation metal.
3. The catalyst or method defined in claim 1 or 2, wherein the second crystals are inter-developed and form at least a partial coating on the first crystals.
4. The catalyst or method defined in any of the preceding claims, wherein the catalyst contains less than 5% by weight non-zeolitic binder based on the combined weight of the first zeolite and the second zeolite.
5. 5. The catalyst or method defined in any of the preceding claims, wherein the first crystals have an average particle size greater than 0.1 microns.
6. The catalyst or method defined in any of the preceding claims, wherein the second crystals have an average particle size that is smaller than that of the first crystals.
7. The catalyst or method defined in claims 5 and 6, wherein the average particle size of the first crystals is from 1 to 6 microns and the average particle size of the second crystals is from 0.1 to 0.5 microns.
8. 8. The catalyst or method defined in any of the preceding claims, wherein the second crystals are at least partially resistant to attrition.
9. 9. The catalyst or method defined in any of the preceding claims, wherein the second zeolite has lower acidity than the first zeolite.
10. The catalyst or method defined in any of claims 1 to 8, wherein the second zeolite has higher acidity than the first zeolite.
11. The catalyst or method defined in any of the preceding claims, wherein the first zeolite and the second zeolite are each, independently, a composition having the following molar ratio: X203: (n) Y02, where X is aluminum, boron, titanium, iron and / or gallium, Y is silicon, tin and / or germanium, and n has a value of at least 1.
12. The catalyst or method defined in claim 11, wherein the first zeolite is an aluminosilicate with a molar ratio of silica to alumina from 70: 1 to 700: 1 or a silicate of gallium with a molar ratio of silica to galia from 20: 1 to 500: 1, and / or the second zeolite is an aluminosilicate with a molar ratio of silica to alumina greater than 200 or a gallium silicate with a molar ratio of silica to galia greater than 100.
13. The catalyst or method defined in any of the preceding claims, wherein the first zeolite and the second zeolite independently each have a large pore size or an intermediate pore size, preferably each being of intermediate pore size.
14. The catalyst or method defined in any of the preceding claims, wherein the first zeolite and the second zeolite are each independently of a structure type selected from the group consisting of OFF, BEA, MAZ, MEI, FAU, EMT, LTL , VFI, MOR, MFI, MFS, MEL, MTW, MTT, FER, EUO, HEU, TON, CHA, ERI, KFI, LEV and LTA.
15. 15. The catalyst or method defined in claim 14, wherein the first zeolite and the second zeolite have an LTL-like structure.
16. 16. The catalyst or method defined in claim 14, wherein the first zeolite and the second zeolite each independently have an MFI or MEL structure.
17. 17. The catalyst or method defined in any of the preceding claims, wherein the hydrogenation / dehydrogenation metal comprises a metal of group VIIIA, or a noble metal.
18. The catalyst or method defined in any of the preceding claims, wherein the hydrogenation / dehydrogenation metal is present in the catalyst in an amount of 0.05 to 3.0% by weight.
19. The catalyst or method defined in any of the preceding claims, wherein the conversion of the silica agglutinant is carried out by aging the silica-bonded aggregate containing the hydrogenation / dehydrogenation metal and the first crystals of the first zeolite. elevated temperature in an aqueous ionic solution containing a sufficient hydroxy ion source to convert the silica binder into the second zeolite.
20. The catalyst or method defined in any of the preceding claims, wherein the aggregate bonded to silica is prepared by forming an extrudable mass containing silica and the first crystals of the first zeolite, extruding the extrudable mass to form an extrudate, and optionally calcining the extruding.
21. 21. The catalyst or method defined in claim 20, wherein the metal is present in the first zeolite prior to forming the extrudable mass.
22. 22. The catalyst or method defined in claim 20, wherein the metal is present in the silica of the extrudable mass.
23. 23. The catalyst or method defined in claim 20, wherein the extrudate is calcined and the metal is incorporated into the extrudate after calcination.
24. 24. The catalyst or method defined in claim 19, wherein the metal is introduced into the aggregate by addition to the aqueous solution.
25. 25. A process for converting hydrocarbons or oxygenates, comprising contacting feed material comprising hydrocarbon or oxygenate under hydrocarbon or oxygenate conversion conditions with a zeolite catalyst linked to zeolite according to claim 1, or any of claims 3 to 24 when dependent on claim 1, or with a zeolite catalyst linked to zeolite prepared by the method of claim 2, or any of claims 3 to 24 when dependent on claim 2.
26. 26. The process defined in claim 25, wherein the conversion is selected from the group consisting of disintegration (cracking) of hydrocarbons, isomerization of alkyl-aromatics, dewaxing of hydrocarbons, dealkylation of alkyl-aromatics, reforming of naphtha to aromatics, conversion of paraffins and / or olefins in aromatics, and oxygenate-two conversion into hydrocarbon products.
27. 27. The process defined in claim 25 or 26, wherein the conversion is carried out at conditions comprising a temperature of 100 to 760 ° C and / or a pressure of 10.1 kPa to 10.1 MPa (0.1 to 100 atmospheres) and / or a space hourly speed in weight of 0.09 to 200 hr_1.
28. The process defined in claim 25, 26 or 27, wherein the conversion process is xylene isomerization, isomerization of an aromatic C8 stream comprising ethylbenzene, isomers of xylene, or mixtures thereof, alkyl-aromatic dealkylation, reforming of aliphatic compounds to aromatics, paraffin dewaxing, or combinations thereof.
29. 29. The process defined in claim 25, 26 or 27, which comprises reforming paraffins to aromatic compounds, wherein, in the zeolite catalyst bound to zeolite, the first zeolite is zeolite L and the second zeolite is zeolite L.