GB2451864A - Composite core-shell catalysts and absorbents having outer inorganic layers - Google Patents

Abstract

Materials are disclosed which comprise inorganic composites having a core-shell structure and an additional inorganic material deposited or grown on or from the shell. The core may be a zeolite or a hollow polymer particle. The shell layer is a particulate inorganic material and may be a zeolite or other molecular sieves such as silcates or a mixed metal oxide such as a perovskite. The additional inorganic material may be an active layer such as zeolite or a matrix material. The structures may be manufactured by methods utilizing charge reversal to ensure that inorganic particulate material of the shell layer is attracted and bonded to the core particle and then subsequent deposition of an additional inorganic material upon the shell layer and/or growth of an additional inorganic material on and/or from the shell layer. The materials find use as catalysts and adsorbents and separation media.

Description

COMPOSITE INORGANIC STRUCTURES

INTRODUCTION

100011 The present invention is concerned with composite inorganic structures, methods for their preparation and processes that utilize these structures as catalysts andlor adsorbent materials and/or separation materials. More specifically, this invention is concerned with composite inorganic structures manufactured using inorganic core-shell structured intermediates derived from two or more particulate inorganic materials.

BACKGROUND TO THE INVENTION

10002] Composites of active inorganic materials are known in the art. One group of such materials p I is uiiipusie iflufg11IlL LaLclIySLS dilu 4USOIUCIILS ueriveu irom, iou exaiiipie, iiioieeuiar sieve iiiateriais and/or metal oxides especially mixed metal oxides.

100031 Molecular sieves find many uses in physical, physicochemical, and chemical processes; most notably as selective sorbents, effecting separation of components in mixtures, and as catalysts.

In these applications pore structure within the molecular sieve material is normally required to be open; it is then a prerequisite that any structure-directing agent, or template, that has been employed in the manufacture of the molecular sieve be removed, usually by calcination. Numerous materials are known to act as molecular sieves, among which zeolites form a well-known class.

[0004] In International Application WO 94/25151 is described a supported inorganic layer comprising optionally contiguous particles of a crystalline molecular sieve, the mean parcle size being within the range of from 20 nm to I.tm. This is a membrane.

100051 In International Application WO 96/0 1683 a membrane structure is described which comprises a planar support, a seed layer and an upper layer.

f0006J In International Application WO 97/25 129 a membrane structure is described which comprises a crystalline molecular sieve layer on a planar support and an additional layer of refractory material to occlude voids in the molecular sieve layer.

[0007] In International Application WO 96/0 1686 a membrane structure is described which comprises a substrate, a zeolite or zeolite-like layer, a selectivity enhancing coating in contact with the zeolite layer and optionally a permeable intermediate layer in contact with the substrate.

100081 In International Application WO 99/2803 1 a zeolite catalyst is described which is partially coated with a second zeolite and having controlled surface acidity and which may be used as a catalyst for hydrocarbon conversion processes.

100091 In International Application WO 99/28032 a zeolite catalyst is described which is bound by MFI structure type zeolite and which may be used as an adsorbent or as a catalyst for hydrocarbon conversion processes.

[0010] In International Application WO 2000/66263 is described a zeolite bound catalyst containing at least three different zeolites and its use as a catalyst for hydrocarbon conversion processes.

[0011) In Published United States Patent Application No. US2002/0 179887 is described an Inorganic composite comprising perovskite supported on an alumina support. The composite is prepared by the physical mixing of perovskite and alumina followed by sintering.

10012) In United States Patent No. 6,372,686 is described an inorganic composite comprising perovskite supported on a cordierite or an alumina support. The composite is prepared by VCiIIUGLIII LL.c,jIIIIUc.

100131 In International Application WO 97/33684 there is described a process for the manufacture of molecular sieve films which utilizes colloidal zeolites in combination with charge reversal to deposit a monolayer of colloidal zeolite on a substrate which is then grown into a thin continuous and dense film.

100141 In United States Patent No. 5,705,222 is described a process for preparing nanocomposite particles. The particles have an inner core covered with a polymer layer and an outer layer of shell particle coatings, The nanocomposites are used in the manufacture of ceramic bodies and are derived from nitrides, carb ides or metal oxides.

100151 Various techniques have been used in the art to prepare composite catalysts but these techniques have problems and limitations. One particular challenge is to be able to effectively incorporate multiple catalytic and/or adsorbent functionalities in a single composite catalyst. It is particularly difficult to produce core-shell catalyst and adsorbent composite structures without detrimentally affecting the properties of the core component of the composite, whilst at the same time obtaining the desired type and quality of shell component of the composite. It is often found that in attempting to prepare a particular shell material the core material is changed or its properties are detrimentally affected. In some instances it has been found to be impossible to prepare certain shell structures in the presence of certain core materials; the nature of the core material is such that conventional synthesis and manufacturing techniques are unable to provide the desired shell material. A further problem is that in many applications it is envisaged that the ratio of core material to shell material in the final composite will be critical in obtaining optimum performance from the composite. The problem here is that obtaining the desired proportions of core to shell is fraught with difficulty due to the lack of control provided by conventional manufacturing techniques and material limitations.

[0016] Therefore, there is a continuing need for new composite inorganic structures and for easily controllable methods for their manufacture that provide catalytic and/or adsorbent materials and/or separation materials of good quality and acceptable performance.

SUMMARY OF THE INVENTION

[0017J It is an object of the present invention to provide composite inorganic structures that are catalytically active and/or have adsorbent and/or separation properties, methods for the manufacture O of such structures and their use in adsorption and/or separation and/or hydrocarbon conversion processes.

10018] The present invention accordingly provides a composite inorgailic structure comprising (i) an inorganic composite having a core-shell structure, the core comprising particulate material and the shell layer comprising a plurality of inorganic particles and (ii) at least one additional inorganic material deposited upon the shell layer or grown on and/or from the shell layer.

[0019J In a preferred embodiment the composite inorganic structures of the present invention comprise at least one active inorganic material. The term "active" in relation to the materials used and composite structures of the present invention and as used herein refers to inorganic materials that are catalytically active and/or have adsorbent and/or separation properties. Thus the composite inorganic structures, when "active", are characterised by the presence of catalytic and/or adsorbent and/or separation functionality, otherwise termed active hinctionality', preferably multiple such active functionalities.

10020J In a further aspect the present invention provides a method for the manufacture of a composite inorganic structure, which method comprises (a) providing an inorganic composite having a core-shell structure prepared by (I) treating (i) a particulate core precursor material A and/or (ii) a plurality of particles of one or more inorganic shell precursor materials B, so as to induce a change in the surface charge of the particle(s) of A and/or B such that the particulate core precursor A has an opposite surface charge from that of the particles of shell precursor materials(s) B and (II) bringing the oppositely charged particles of A and/or B into contact with each other under conditions such that the particles of inorganic shell precursor material(s) B become bonded to the surface of the particulate core precursor A to form the inorganic composite having a core-shell structure, (b) providing a precursor to an additional inorganic material, and (c) contacting and/or treating the inorganic composite provided in (a) and the precursor provided in (b) under such conditions that additional inorganic material is deposited upon and/or grown onto or from the shell layer of the inorganic composite.

10021) The above is alternatively stated as a method for the manufacture of a composite inorganic structure, which method comprises (a) providing an inorganic composite having a core-shell structure prepared by (I) treating (i) a particulate core precursor material A or (ii) a plurality of particles of one or more Inorganic shell precursor materials B, or (iii) a particulate inorganic core precursor material A and a plurality of particles of one or more inorganic shell precursor materials B, so as to induce a change in the surface charge of the particle(s) of A and/or B such that the particulate core precursor A has an opposite surface charge from that of the particles of shell precursor material(s) B and (II) bringing the oppositely charged particles of A and B into contact with each other under conditions such that the particles of inorganic shell precursor material B become bonded to tile surface of the particulate core precursor material A to form the inorganic composite having a core-shell structure, (b) providing a precursor to an additional inorganic material, and (c) subjecting the inorganic composite provided in (a) and the precursor provided in (b) to conditions such that at least one of the following effects occurs: -additional inorganic material is deposited upon the shell layer of the inorganic composite; -additional inorganic material is grown upon the shell layer of the inorganic composite; -additional inorganic material is grown from the shell layer of the inorganic composite.

100221 In a further aspect the present invention provides a conversion process for converting hydrocarbons comprising contacting a hydrocarbon feedstream under hydrocarbon conversion conditions with a composite inorganic structure of the invention as defined above or a structure manufactured by the method as defined above to effect conversion of the hydrocarbon feedstream.

[0023) Yet another aspect of the present invention provides an adsorption or separation process which comprises contacting a feedstream containing one or more adsorbates under adsorption or separation conditions with a composite inorganic structure of the invention as defined above or a structure manufactured by the method as defined above to effect adsorption or separation of one or more of the adsorbates from the feedstream.

100241 Other features, aspects and advantages of the invention will become better understood with reference to the following description of the invention, the claims, and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

100251 FIGURE 1 is the Scanning Electron Micrograph (SEM) of a composite inorganic structure according to the invention having an LTL zeolite core and continuous MFI zeolite layer grown from an MFI zeolite shell layer over the core.

100261 FIGURE 2 is an SEM of a composite inorganic structure according to the invention having a core of FAU zeolite crystals and a continuous layer ofZSM-5 zeolite grown from a silicalite-I shell laycr over the core.

100271 FIGURE 3 is an SEM of a composite inorganic structure according to the invention having a core of ZSM-48 zeolite crystals covered with a continuous layer of ZSM-5 zeolite grown from a silicalite- I shell layer over the core.

[0028] FIGURE 4 is an SEM of a composite inorganic structure according to the invention having a core of ZSM-23 zeolite crystals covered with a continuous layer of ZStvi-5 zeolite grown from a silicalite-l shell layer over the core.

100291 FIGURE 5 is an SEM of a composite inorganic structure according to the invention having a core of crystalline FAU zeolite covered with a continuous layer of MFI zeolite grown from a silicalite-I shell layer over the core.

100301 FIGURE 6 is an X-ray diffraction (XRD) pattern of the material of Figure 5.

100311 FIGURE 7 is an SEM of a composite inorganic structure according to the invention having a core of crystalline FAU zeolite covered with a continuous layer of MFI zeolite grown from a silicalite-I shell layer over the core, the shell layer being relatively thin.

100321 FIGURE 8 is an XRD pattern of the material of Figure 7.

100331 FIGURE 9 is an SEM of a composite inorganic structure according to the invention having a core of crystalline FAU zeolite with an MFI zeolite binder grown from converted silica binder and the core having a shell layer of silicalite-1.

[0034J FIGURE 10 is a graphical representation of the liquid phase adsorption analysis for the samples of Examples 9, 10 and II.

100351 FIGURE 11 is the XRD pattern for a mixed metal oxide (perovskite) precursor of formula: (Lao 6Ca0 4Fe0 2Mn0 803).

[0036J FIGURE 12 is the SEM of the material of Figure II.

100371 FIGURE 13 shows the SEM of a perovskite treated ZSM-5 core crystal without removal of excess cationic polymer.

100381 FIGURE 14 shows the SEM of an inorganic composite having a shell core-shell structure and as used in the present invention, having a perovskite shell on a ZSM-5 core crystal.

100391 FIGURE 15 shows the XRD pattern for the material of Figure 14.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

100401 The composite inorganic structures of the present invention comprise and are manufactured through the use of a key intermediate being an inorganic composite having a core-shell structure.

Such intermediate inorganic composites are now discussed in more detail. Thus, the core of these intermediate composites may comprise inorganic materials that are active or inactive or mixtures of such materials. Alternatively the core may comprise solid organic particles or hollow organic particles e.g. polymeric spheres or hollow particles of other shapes. It is also envisaged that these core particles may be made of metals or ceramic materials. It is envisaged in one embodiment that the core material may comprise an active material imparting the desired activity to the composite iliorgaHic structure of the invention. The core material may comprise a single material or a mixture of different materials. The particulate core may be a single particle or alternatively an agglomerated particle comprising a plurality of smaller particles. The particles of such plurality of smaller particles may be of the same material or may be two or more particles of different materials In this embodiment one or more or all of the particles making up the agglomerated particle may be an active material. Hereinafter the particulate core, whether comprising a single particle or an agglomeration of particles, may simply be referred to as a "core or "particle" for convenience.

100411 In a further aspect of the present invention it is envisaged that the shell layer of the inorganic composite having a core-shell structure may comprise one or more active materials that impart the desired activity to the composite inorganic structure of the invention. It is envisaged that the shell layer may comprise particles that are substantially identical to each other in terms of their chemical composition and/or properties and/or size and/or structure and/or shape. Alternatively, the particles making up the shell layer may be two or more materials that differ from each other in some way, such as composition and/or properties and/or size and/or structure and/or shape; it is preferred however that at least one of these particles is an active material and more preferably that all of the particles are active materials. When the shell layer comprises a plurality of different particulate materials it is envisaged that substantially all of the materials may be active materials. It is also envisaged that when there are two or more different particulate materials in the shell layer they may be materials having differing activity, meaning different types and/or magnitudes of activity.

100421 The core and shell may comprise particles of the same material type e.g. they may both be molecular sieve materials such as materials with catalytic activity and/or adsorption and/or separation properties. The core and shell may comprise particles of the same material.

[00431 The inorganic composites having a core-shell structure may have an organic, inorganic or metallic core, which is inactive or active, and an inorganic shell which is inactive or active but which is preferably active.

(0044J The shell of the inorganic composite having a core-shell structure may comprise a single layer of inorganic particles and the layer may be contiguous, meaning that each particle of the shell is in contact with at least one other shell particle. Preferably each shell particle is in contact with at least two, more preferably several, other shell particles. This arrangement results in a film like layer of shell material encapsulating the particulate core (particle or particles). The particles of the shell may be in the form of a monolayer. The term monolayer in the context of the present invention is taken to mean a layer comprising particles which are substantially in the same plane deposited on a substrate, i.e. the particulate core. It will be understood that the monolayer will be disposed on the "plane" (which normally will not be fiat) defined by the surface of the particulate core. The particles and other materials if present may be close packed to provide a classical monolayer. Alternatively the particles and other materials if present are not close packed and therefore are present as a sub-monolayer.

100451 Preferably the shell layers are thin layers. The shell layer may for example have a maximum thickness of 2000 nm, preferably of 1000 nm, more preferably of 500 nm and most preferably of 250 nm. The minimum thickness of the shell will depend on the diameter of the shell particles but may be, for example 10 nm, which thickness is therefore the preferred lower end of the shell thickness ranges where the upper end of those ranges are the maximum values given above.

Preferably the shell thickness and/or the average shell thickness is in the range of from 10 to 2000 nm, more preferably 25 to 1000 nm and most preferably 50 to 500 nm.

[0046J In the inorganic composite having a core shell structure the particulate core is of significantly larger dimensions than the particles that make up the shell layer. I'he particulate core (whether a single particle or an agglomerate of two or more particles) may be considered to have a "particle size" that is the largest dimension of the particle or agglomerate. The "average particle size" of a plurality of core particles andlor agglomerates that are employed in manufacturing the active inorganic composites may be determined by measuring the largest dimension of a representative number (for example, 30) of representative core particles or agglomerates eg by means of scanning electron microscopy. The average particle size can then be calculated by normal mathematical means, that is summing the largest dimensions of'n' (say, 30) representative particles and dividing the sum by n'. It is preferred that the particulate core of the inorganic composite having a core-shell structure has an average particle size of 100 nm or greater, preferably 500 nm or greater, even more preferably 600 nm or greater and most preferably 1000 nm or greater. Preferably the particulate core has an average particle size of 100 to 5000 nm, more preferably 200 to 3000 nm, even more preferably 400 to 2000 nm and most preferably 500 to 1000 nm. It is preferred that the shell particles have an average particle size of 1000 nm, more preferably 500 nm, even more preferably 300 nm such as 200 nm and most preferably 100 nm. Ideally the shell particles have an average particle size within the range of from Ito 300 nm, more preferably within the range of from 2 to 200 nm, even more preferably within the range of from 5 to 150 nm and most preferably within the range oflOto lOOnm.

10047] The particulate core and/or the particles of the shell particles may be of any inorganic material with the preference that at least the shell comprises at least one active inorganic material as hereinbefore defined.

InfliOl:LIt.c_.: -. _:_i_r_L_ _LlI J Uu4oJ JII SUILc2UIC t.IdSS UI 4LLIVC III4LCI I4IS 101 LII SuCh 4IIU hUh USC CISChiCJC III LIIC L0h1IUSILC inorganic structures of the present invention are molecular sieves. Molecular sieves can be classified in various categories, for example according to their chemical composition and their structural properties. A group of molecular sieves of commercial interest is the group comprising the zeolites, which arc defined as crystalline aluminium silicates. Another category of interest is that of the metal silicates, structurally analogous to zeolites, but for the fact that they do not contain aluminium (or only very small amounts thereof). Suitable molecular sieves for use in the present invention therefore include silicates, aluminosilicates, aluminophosphates, silicoaluminophosphates, metalloaluminophosphates and nietalloaluminophosphosilicates. An excellent review of molecular sieves is given in Molecular Sieves -Principles of Synthesis and identification" (R. Szostak, Van Reinhold, New York, 1989).

10049] Apart from their chemical composition molecular sieves are also classified according to their structure type. Representative examples are molecular sieves/zeolites of the structure types AFI, AEL, BEA, CHA, EUO, FAU, FER, KFI, LTA, LTL, MAZ, MOR, MEL, MU, MTW, OFF, TON, MWW and, especially, MFI; as well as other microporous materials for which no structure type code has been assigned such as intergrown materials like ZSM-48 or precursor materials such as members of the MCM-22 family. Some of these materials whilst not being true zeolites as such are frequently referred to in the literature as such. Examples of molecular sieves that are of major interest for the present invention include those of structure type LTL, MFI, FAU, MOR, particularly the materials ZSM-5, ZSM-12 ZSM-23, ZSM-48 and materials of the MCM-22 family.

100501 The term "MCM-22 family material" (or "material of the MCM-22 family" or "molecular sieve of the MCM-22 family" or "MCM-22 family zeolite'), as used herein, includes one or more of: * molecular sieves made from a common first degree crystalline building block unit cell, which unit cell has the MWW framework topology. (A unit cell is a spatial arrangement of atoms which if tiled in three-dimensional space describes the crystal structure. Such crystal structures are discussed in the "Atlas of Zeolite Framework Types", Fifth edition, 2001, the entire content of which is incorporated as reference); * molecular sieves made from a common second degree building block, being a 2-dimensional tiling of such MW\V framework topology unit cells, forming a monolayer of one unit cell thickness, preferably one c-unit cell thickness; * molecular sieves made from common second degree building blocks, being layers of one or more than one unit cell thickness, wherein the layer of more than one unit cell thickness is made from stacking, packing, or binding at least two monolayers of one unit cell thickness.

The stacking of such second degree building blocks can be in a regular fashion, an irregular fashion, a random fashion, or any combination thereof and molecular sieves made by any regular or random 2-dimensional or 3-dimensional combination of unit cells having the MWW framework topology.

100511 Molecular sieves of the MCM-22 family include those molecular sieves having an X-ray diffraction pattern including d-spacing maxima at 12.4�0.25, 6.9�0.15, 3.57�0.07 and 3.42�0.07 Angstrom. The X- ray diffraction data used to characterize the material are obtained by standard techniques such as using the K-alpha doublet of copper as incident radiation and a diffractometer equipped with a scintillation counter and associated computer as the collection system. The MCM-22 family materials are further discussed in W.J. Roth, Stud. Surf. Sc. Cat. 158, 19-26 (2005).

10052] Materials of the MCM-22 family include MCM-22 (described in U.S. Patent No 4,954,325), PSH-3 (described in U.S. Patent No. 4,439,409), SSZ-25 (described in U.S. Patent No. 4,826,667), ERB-l (described in European Patent No. 0293032), ITQ-l (described in U.S. Patent No 6,077,498), ITQ-2 (described in International Patent Publication No. W097/l 7290), MCM-36 (described in U.S. Patent No. 5,250,277), MCM-49 (described in U.S. Patent No. 5,236,575), MCM- 56 (described in U.S. Patent No. 5,362,697), UZM-8 (described in U.S. Patent No. 6,756,030), and mixtures thereof. Molecular sieves of the MCM-22 family are useful as the alkylation catalysts.

Particular members of the MCM-22 family that may be used in alkylation reactions include MCM- 49, MCM-56 and isotypes of MCM-49 and MCM-56, such as ITQ-2.

100531 The morphology of the active material that may be employed as the particulate core and/or as the shell particles in the intermediate inorganic composites used to make the structures of the -10-invention may be varied. For example the particles of core or shell may be substantially spherical or of layered or pillared structure as discussed in Roth (idem).

10054] The preferred molecular sieve that may be employed as core and/or shell will depend on the chosen application for the final composite inorganic structure. This may be for example, separation e.g. by adsorption or catalytic applications or combined reaction and separation. The molecular sieve selected will also depend on the size of the molecules being treated. There are many known ways to tailor the properties of the molecular sieves, for example, structure type, chemical composition, ion-exchange, and activation procedures.

100551 Further classes of active materials that may be used in the composite inorganic structures of the present invention are the active metal oxides and especially the active mixed metal oxides. These are described in, for example, Rodriguez, Catalysis Today 85, 177-192 (2003). Mixed-metal oxides play a very important role in many areas of chemistry, physics, materials science, and geochemistry.

In technological applications, they are used in the fabrication of microelectronic circuits, piezoelectric devices and as catalysts. For example, mixed metal oxides are active catalysts for the 1 5 selective hydrogenation and isomerization of olefins, the water-gas shift reaction, dehydrogenation of alcohols, the oxidation of CO and alkanes, NO reduction, S02 destruction, photolysis of water.

etc. In principle, several phenomena can contribute to the superior performance of these complex systems, so scientific criteria are applied in choosing the "right" combination of elements when designing a mixed-metal oxide catalyst. With respect to single-metal oxides, the chemical behavior of mixed-metal oxides may be different as a consequence of several factors. In some situations, the cations in a mixed-metal oxide can work in a cooperative way catalyzing different steps of a chemical process. Furthermore, the combination of two metals in an oxide matrix can produce materials with structural or electronic properties that can lead to superior catalytic activity or selectivity. At a structural level, a dopant can introduce stress into the lattice of an oxide host, inducing in this way the formation of defects that have a high chemical activity. On the other hand, the lattice of the oxide host can impose on the dopant element non-typical coordination modes with a subsequent perturbation in the dopant chemical properties. Finally, metal/metal or metal/oxygen/metal in teractions in mixed-metal oxides can give electronic states not seen in single-metal oxides.

10056] The nature of the mixed metal oxide is preferably designed in dependence on the type of application envisaged for the active inorganic composite structure of the invention. Thus, from a knowledge of the catalytic function required for the target application, the "right' combination of elements is selected in order to make a mixed metal oxide having suitable catalytic performance for the application. Guidelines for such design of mixed metal oxides have been described in the literature. Examples of such publications, each incorporated herein by reference, include: I.E. Wachs et al., Catalysis Today, 78, 13-24 (2003); I.E. Wachs et al., Catalysis Today, 100, 79-94 (2005); E Bordes et al., Catalysis Today, 61, 197-201 (2000); and E. Bordes et al., Phys. Chem. Chem. Phys., 1, 5735-5744 (1999).

(00571 For some applications, the metal oxides/mixed metal oxides may for example comprise one or more metals selected from La, Ca, Fe, and Mn The mixed metal oxides may have for example a perovskite structure.

100581 It is preferred that the shell layer is derived from particles that are colloidal in nature. When the shell particles are molecular sieve it is preferred that they are nanocrystals and are molecular sieve nanocrystais with a size of less than 200 nm, preferably 120 nm, the crystal structure of which can be identified by X-ray diffraction. There are various methods described in the art for the preparation of such colloidal particles. International Application WO 94/05597, the teaching of 1 5 which is hereby incorporated by reference, describes a method whereby it is possible to synthesize colloidal suspensions of discrete molecular sieve particles. Such particles are suitable for use in the preparation of the shell structures that are employed according to the present invention. Molecular sieves such as zeolites or crystalline microporous metal silicates are generally synthesized by hydrothermal treatment of a silicate solution with a well-defined composition. This composition, as well as the synthesis parameters such as temperature, time and pressure, determine the type of product and the crystal shape obtained. These materials may also be prepared in accordance with the methods set forth in WO 93/08 125 the teaching of which is hereby incorporated by reference. In that method, a synthesis mixture is prepared by boiling an aqueous solution of a silica source and optionally an organic structure directing agent under conditions suflicierit to cause substantially complete dissolution of the silica source. The organic structure directing agent, if used, is advantageously introduced into the synthesis mixture in the form of a base, specifically in the form of a hydroxide, or in the form of a salt, e.g., a halide, especially a bromide. Mixtures of a base and a salt thereof may be used, if desired or required, to adjust the pH of the mixture.

(00591 The colloidal particles are capable of forming a stable dispersion and produce particularly suitable shell layers for the inorganic composite structures of the present invention. Representative examples of molecular sieves (zeolites) which can be used to prepare the shell layer, for example from colloidal particles, include but are not limited to those of structure types AFI, AEL, BEA, Cl-IA, EUO, FAU (includes zeolite X and zeolite Y), FER, KFI, LTA, LTL, MAZ, MOR, MEL, -12-MTN, MTT, MTW, MWW, OFF, TON zeolite beta, ZSM-48 and especially MFI zeolites. Other suitable molecular sieve particles may be prepared by the methods described in PCT/EP96/03096, PCT/EP96/03097, and PCTIEP96/03098, the disclosures of which are all hereby incorporated by reference.

10060] The core and/or shell of the inorganic composite having a core-shell structure that forms part of the structure of the invention, may each comprise a mixture of more than one material, and when they are mixtures the second and other materials may or may not be inorganic materials and/or may not be active inorganic materials. It is preferred that both the core and the shell comprise at least one active inorganic material. It is preferred that the core comprises a single inorganic active material. It is also preferred that the shell comprises a single inorganic active material that may or may not be the same material as the core. The core and the shell may, and for many uses advantageously do, consist essentially of inorganic active material e.g. molecular sieve or mixed metal oxide catalysts and/or adsorbents, or they may be a mixture of the inorganic active material and intercalating materials which may be organic or inorganic. The intercalating materials may be the same in both the core and the shell. For the shell the intercalating materials may be applied simultaneously with or after deposition of the active inorganic material. The intercalating material is advantageously present in a sufficiently low a proportion of the total material of the shell such that the active inorganic particles remain contiguous. Suitable materials for the core and for the shell include, for example, silica and/or metal oxide; metal particles; metal particles with metal oxides and/or silica. The shell layer may be formed, for example, from a solution containing nanocrystalline or colloidal active inorganic particles or a mixture of metal oxide and nanocrystalline or colloidal active inorganic particles or a mixture of nanocrystalline or colloidal active inorganic particles and colloidal metal. Preferably, nanocrystalline or colloidal active inorganic materials or a mixture of nanocrystalline or colloidal active inorganic material and metal oxide are used to form the shell layer. The metal oxides from which the shell layer may be prepared may be, for example, colloidal metal oxides or polymeric metal oxides prepared from sot-get processing. In this aspect of the present invention the metal oxides which may be used are preferably selected from the group consisting of colloidal alumina, colloidal silica, colloidal zirconia, colloidal titania and polymeric metal oxides prepared Irom sot-gel processing and mixtures thereof. The colloidal metals which can be used include copper, platinum and silver.

(0061] The method of manufacture of the present invention requires that either the surface of the core particles are treated or the surfaces of the shell particles arc treated or both the core and shell particles are treated so as to induce a reversal of the surface charge of one or both of the particle -13 -groups. It is preferred that when the core is treated its surface charge is reversed from negative to positive. Charge reversal may be achieved by pH control or other chemical and/or non-chemical methods. In a preferred embodiment the surface charge reversal of the core and/or shell particles is achieved by chemical treatment. Preferably this is achieved through the use of one or more polymers and most preferably the polymer or polymers used are cationic polymers. In a preferred embodiment the treated particle or particles are washed after treatment so as to remove excess chemical treatment agent.

0O62I When molecular sieve materials are used as the core particle it should be remembered that the majority of the molecular sieves of interest in the present invention are metal silicates and these may be characterized as having a negative charge in neutral or alkaline aqueous suspensions. The magnitude of the surface charge is generally at its highest in the pH range 8-12 and hence this pH range is suitable fbi adsorbing (bonding) shell particles onto these core particles.

100631 In addition certain types of molecular sieves are typically prepared in the presence of tetraalkyl ammonium ions in stoichiometric excess. In such cases, the adsorption (bonding) of shell particles is promoted if the excess tetraalkyl ammonium ions in these particles are replaced by, for instance, ammonium ions. This may be achieved by allowing the shell particle suspension to pass through a column packed with an organic ion exchange resin in the ammonium form, or by adding ion exchange resin in such form to a particle containing suspension and, after complete ion exchange, separating the ion exchange resin from the suspension through for example filtration or centrifugation.

[0064J The charge reversal may be achieved by treating the particles with a cationic polymer, preferably in the form of a solution containing for example 0.1 to 4 weight % cationic polymer. The pH value for the charge reversal is selected after considering both the particle and the polymer chemistry. However, cationic polymers may be used within a wide pH range. The repeat unit in such polymers can be for example quaternary amines with hydroxyl groups in the main chain. An example of such a polymer is Berocell 6100, a water soluble polymer with a repeat unit [CH2CH(OH)CH2N(CI-l3)2]+ and a molecular weight of about 50,000 g/mol, marketed by Akzo Nobel AB, Sweden, Other suitable cationic polymers are well known in the art.

100651 For certain particles it may be advantageous, in order to impart to them satisfactory surface properties, to submit them to one or more pre-treatment steps, aimed at cleaning their surface or modifying their surface chemistry. In such cases, it is advantageous to treat the particles in one or more alkaline, acid or oxidizing cleaning steps, or combinations of such steps. Another way of enhancing shell layer deposition is to carry out the adsorption (bonding to the particulate core) in two -14-or more steps, as the case may be, with an intermediate charge reversal. In some cases coupling agents may be used in the particle that is not subjected to surface charge reversal, for instance of the silane type. These may be used according to known techniques. Such coupling agents are characterized by the fact that they consist of two functional groups, one of them having affinity for one particle surface e.g core particle surface and the second one binding to the other particle surface e.g. of the shell particles. For bonding molecular sieve e.g. zeolite or metal silicate particles to particle surfaces that are highly metallic in nature, silane containing a thiol group is often suitable.

Coupling agents are made by for example Dow Coming and Union Carbide and they are generally used for incorporating inorganic fillers and reinforcing agents into organic polymers. The coupling 1 0 agent may be deposited on the particle and then hydrolyzed to provide the required surface charge or it may have inherent functionality which provides the required charge. Suitable coupling agents are chemicals which are well known in the art. Examples are those supplied by OSi specialties as "Silquest Silanes" and as indicated in their 1994 brochure for these products. The coupling agent may be utilized in conjunction with the cationic polymers as indicated above to provide the required surface charge. Thus the charge reversal or control may be achieved by: utilization of the appropriate pH of the solution into which the substrate is immersed and which contains the particles to induce opposite charges on particle surfaces; deposition of a cationic polymer which imparts appropriate charge reversal; or utilization of a coupling agent with or without hydrolysis and! or with a suitable cationic polymer.

[00661 The shell deposition process may be repeated a number of times in order to ensure the complete formation of a true shell layer e.g. a monolayer or to achieve the desired density of coverage of the core particle substrate surface with a sub-monolayer.

[00671 For certain types of molecular sieves, a final calcination step is desirable and often necessary to bum off the organic molecules in the pore structure, thus providing an internal pore structure available for adsorption, separation, catalysis or ion exchange. It is preferred that the core-shell inorganic composites prepared in order to permit manufacture of the composite structures according to the present invention are calcined. For example this may comprise a treatment in air at a temperature exceeding 400 °C.

100681 In a fUrther embodiment, after formation of the shell via deposition of particles, the resultant inorganic composite having a core-shell structure may not be active because the materials used as the core or as the shell layer may not be active inorganic materials. In this situation a further process step may be used to convert one or more of the materials of the core and/or shell from inactive inorganic materials or precursors into the desired active inorganic material or materials. For -15 -example the shell may comprise silica, which may be converted to molecular sieve e.g. a zeolite under appropriate conditions e.g. hydrothermal synthesis conditions and with use of an appropriate synthesis solution. After hydrothermal treatment the shell is converted from inactive material into active material to produce an inorganic composite having a core-shell structure and active material therein It may be that all of the material of the shell layer is converted to active material or only those portions with the requisite precursor properties for conversion to an active material e.g. zeolite.

100691 The inorganic composites having a core-shell structure as described hereinbefore arc swtable for use to prepare composite inorganic structures according to the invention. These composite inorganic structures comprise the inorganic composites having a core-shell structure in combination with one or more additional inorganic materials. This additional inorganic material may comprise for example, a binder material that has been converted to an active material or a further shell layer of active inorganic material that has been deposited upon and/or grown from or on the shell layer. When used, the binder may be converted in whole or in part into active inorganic material. In some instances the composite inorganic structures are particulate materials that would not normally be used as such and which may as described below be used in the form of a pill, sphere or extrudate with binder. In some instances the composite inorganic structure will be formed from a pill, sphere or extrudate made from binder in which an inorganic composite having a core-shell structure has been dispersed by conversion of the binder to active material.

100701 Thus in one embodiment the composite inorganic structure is formed by additional inorganic material being deposited or grown from the shell layer of the inorganic composite particles having a core-shell structure. In this embodiment the additional inorganic material may be the same material as the shell layer. For example the shell layer may comprise MFI zeolite material and additional MFI zeolite may be grown from this MFI zeolite in the shell layer. The chemical composition of the MFI zeolite of the additional material may be the same as or different from the chemical composition of the NIFI zeolite shell layer. Alternatively the additional inorganic material may be of a different structure type and/or composition from that of the shell layer. Thus in the first case the overall effect may be to increase the thickness and/or the permeability characteristic of the shell layer, whereas in the second case a completely new third inorganic material may be grown on or from the shell layer of the inorganic composite having a core-shell structure to provide the composite inorganic structures of the present invention.

10071] In preferred embodiments the additional inorganic material is grown from the shell layer via crystallization and most preferably crystallization under hydrothermal conditions from a synthesis solution for a molecular sieve. -16-

[0072J The additional inorganic material deposited on or grown from the shell may form a complete Continuous layer over the surface of the shell layer or may be present as a discontinuous layer having discrete regions of material. The morphology of this material (which may be considered a third layer where the composite core-shell structure represents the first and second "layers") may be selected by adjusting the ratio of active material e.g. colloidal material and intercalating material such as metal oxide present in the shell layer. The active inorganic material especially when present as colloidal particles may act as nucleation sites for the growth of the third inorganic layer and the density of these sites in the shell layer may be controlled. The nucleation density can be controlled by the relative proportions of active inorganic particles and metal oxides (with the density decreasing as the amount of the metal oxide utilized increases) as well as the size of the active inorganic particles in the shell layer.

[0073] ifl one method the inorganic composite having a core-shell structure is placed in a synthesis mixture without any further treatment of the shell layer after it has been formed. Even when submerged in the synthesis mixture, the particles of the shell layer, which may be in the non-calcincd state, remain adhered to the core particle and are able to facilitate growth of the third inorganic material e.g. a molecular sieve layer. However, under some circumstances, e.g. during stirring or agitation of the synthesis mixture during hydrothermal synthesis, the adhesion between the shell particles and the core particle may be insufficient and steps must be taken to stabilize the shell layer and fix its position before depositing or growing a third layer.

100741 Preferably therefore in this embodiment the shell layer is stabilized or fixed in place before being placed into the synthesis mixture. This stabilization can be achieved in one aspect by heat- treating the shell layer, e.g. at temperatures between 30 and 1000°C, preferably greater than 50 °C and more preferably between 200°C and 1000°C and most preferably greater than 300°C. A particularly preferred range would be 400 to 600°C. This heat treating is preferably for at least two hours with or without steam. In an alternative method of stabilization the shell layer may be treated with a solution that modifies the surface characteristics of the particles in the shell layer. For example, the layer may be washed with a solution that would cause the particles of the shell layer (if they were in colloidal suspension) to flocculate; without wishing to be bound by theory it is believed that a process similar to flocculation in colloidal solutions may also bind the particles in the shell layer more strongly together. Suitable solutions include those which comprise materials which will ion-exchange with the shell layer. These include solutions of divalent metal ions such as for example solutions comprising alkaline earth metal salts. As an example, a wash with a diluted Ca salt e.g. CaCI2 solution may be mentioned. In this aspect there may be included the additional step of heating of the treated shell layer at a temperature of up to 300°C and preferably up to 200°C.

[0075] In one method for the manufacture of composite inorganic structures according to the present invention, the deposited particles of the shell layer especially particles of active material are allowed lo grow. The growth from or of the initially discrete shell particles leads to their intermeshing or the growth of intermeshing particles from their surfaces and the shell layer is transformed into a continuous and dense film of inorganic material grown on or from the shell layer.

The thickness of the thinnest film necessary to obtain a continuous and dense film over the shell layer is dictated by both the size of the deposited or grown inorganic material and the degree of close-packing of the particles of the shell layer and also their orientation within the shell layer. With maximum close-packing, it is in most cases sufficient to grow the material of the third layer into a film thickness corresponding to one and a half times the thickness of the shell layer which when the particles are approximately spherical corresponds to one and a half times the diameter of the initially deposited particles in the shell layer, in order to obtain a continuous third inorganic layer. When the particles of the shell layer have a geometric shape other than spherical then they may be deposited Onto the core particle to provide active inorganic material in the shell layer, which is oriented in some way and may also be close packed. In this case the faces of the particles in the shell layer which are in a plane other than the plane of the shell layer surface, may in fact be the faces of the particles from which the new material growth for the third layer is greatest. The result of this arrangement is that the material of the third layer grows from these faces and forms a dense thin film with little or no growth from the surface plane of the shell layer. Thus in this case a dense third inorganic layer may be produced, which has a thickness which corresponds substantially to the thickness of the original shell layer.

[0076] When the additional inorganic material is a molecular sieve the additional material layer may be grown from a suitable synthesis solution. Suitable molecular sieve synthesis solutions are well known in the art and are described in for example in International Application WO 94/25 151, International Application PCT/EP9310 1209, International Application WO 96/0 1687 and International Application WO 96/0 1685, the teachings of which are all incorporated herein by reference.

(00771 One of the benefits of the method of the present invention is that a composite inorganic structure may be prepared from two different materials e.g. two molecular sieve materials; one a core material and the second a material (the "third layer") grown on or from the shell material, under such conditions that would normally result in one or other of the materials either being chemically attacked under the reaction conditions or not being formed at all. It is believed that the adsorbed (bonded) shell layer of cationic polymer and inorganic shell particles provides some form of protection against such chemical attack and synthesis difficulties, thus enabling complete encapsulation of the inorganic composite (i.e. the core particle and shell layer) by the inorganic third layer, whilst keeping the core material relatively intact and undamaged by the synthesis conditions.

[0078] It is preferred that the shell layers and the "third layers" of the structures of the invention are manufactured to be complete where possible. Of course, the thickness can be controlled by management of manufacturing conditions to a thickness that is appropriate for the intended use of the composite structure.

10079) The method of the present invention allows the preparation of relatively thin films of an additional inorganic material from or on the shell layer. Such thin films may be for example of hI,..-.,.. nflh1.. cnn ii uuv uiii ui ui cvii ui LIIILPJISS.iuu 11111 UI iSS. LolIveIllelILly, tue LiIIu.k1Iess 0' we "thin" films is from 100 to 2000 nm, such as from 500 to 2000 nm. However the method is equally applicable to the preparation of thicker films of an additional inorganic material from the shell layer e.g. films olmaterial up to 150000 nm (150 Ilm) may be prepared using this technique. Thus, the additional inorganic material layer may be for example from 100 to 150000 nm thick, such as from 500 to 150000 nm thick.

100801 In a further approach the composite inorganic structure of the present invention may he prepared from an extrudate comprising inorganic composite having a core-shell structure material within an inorganic matrix; the inorganic matrix being a precursor to an active inorganic material.

The inorganic matrix may be converted in whole or in part into one or more active inorganic materials. One procedure for making such a composite inorganic structure involves converting the silica present in a silica binder of an aggregate of the silica-binder and an inorganic composite having a core-shell structure, to an active material binder e.g. a zeolite binder. The procedure involves aging the silica bound aggregate for sufficient time in an aqueous alkaline solution. A further procedure may be used where seed crystals of an active inorganic material e.g. MFI structure type zeolite seeds, are included in a silica bound aggregate forming mixture containing inorganic composite having a core-shell structure material. The silica binder of the silica bound aggregates can be converted in an aqueous alkaline mixture optionally containing an organic template to form an active material binder.

The seed crystals may be crystalline materials similar to those used to provide the shell layer.

100811 The silica binder used in preparing the silica-bound active material composite aggregate may be commercially available silica The silica does not need to contain significant amounts of alumina and can even contain less than 2000 ppm of alumina.

10082] The seed crystals when used may be added to the silica-bound aggregate forming mixture at any time prior to extruding the mixture. For example, the seed crystals can be added to the silica or inorganic composite having a core-shell structure material used in forming the mixture or can be added directly to the forming mixture. The seed crystals will be present in an amount effective to promote growth of the active material. This will usually be an amount in the range of from about 0.01 to about 2% by weight based on the dry weight of the silica bound extrudate.

[0083] The active composite aggregate used in this embodiment of the present invention to make a composite inorganic structure will usually be prepared by, in a first stage, forming the inorganic 0 composite having a core-shell structure, which is then washed, dried, and optionally calcined to produce a powder. This powder can then in a second stage be mixed with a source of silica e.g. silica 501, togetherw itii the optional seed crystals arid optionally an extrusion aid to form a thick, smooth paste. The paste is then extruded to form the silica-bound extrudate of the core-shell material, which is dried and optionally calcined. The dried or optionally calcined extrudate may then be aged at elevated temperature in a suitable solution. A suitable aging temperature may range from 95 to 200°C. Generally the extrudate is aged at temperatures from 130 to]70°C, preferably 145 to 155°C, most preferably around 150°C. The time during which the extrudate is aged is for example from 10 to 80 hours.

[0084] i'he aqueous ionic solution in which the silica-bound core-shell material is aged preferably contains reduced amounts of hydroxyl ions as higher amounts can result in substantial reduction in the active material composite and aggregate integrity. The amount of hydroxyl ions present in the aqueous ionic mixture will typically be a molar ratio of (0H):(Si02) of less than 0.20, preferably less than about 0.16, or even less depending on the composition of the active material being formed from the binder.

100851 The active material from the binder is usually present in this embodiment of the composite inorganic structure in an amount in the range of from about 10 to about 60 % by weight based on the weight of the inorganic composite having a core-shell structure material present and, more preferably from about 20 to about 50% by weight.

10086] Optionally, the silica binder may contain alumina. The silica binder used in preparing the silica bound active material composite aggregate is preferably a silica sol and may contain various amounts of trivalent elements, e.g., aluminum, gallium, boron, iron, zinc, or mixtures thereof. The amount of silica used is preferably such that the content of the active material in the composite in the dried extrudate at this stage will range from about 40 to 90% by weight, more preferably from about to about 80% by weight, with the balance being primarily silica, e.g. about 20 to 50% by weight silica.

100871 The resulting paste can then be molded, e.g. extruded, and cut into small strands, for example approximately 2 mm diameter extrudates, which are dried for example at 100°C to 150°C for a period of for example 4-12 hours. The e xtrudate may then be calcined for example in air at a temperature of preferably from about 400 to 550°C for a period of for example from about Ito 10 hours.

100881 Optionally, the silica-bound core-shell material can be made into very small particles, which have application in fluid bed processes such as catalytic cracking. This preferably involves mixing the core-shell material with a silica and seed crystals so that an aqueous solution or suspension of core-shell material and silica binder is formed which can be sprayed dried to result in small fluidizibie silica bound core-shell particles. Procedures for preparing such aggregate particles are known to persons skilled in the art. An example of such a procedure is described by Scherzer (Octane-Enhancing Zeolitic FCC Catalyst, Julius Scherzer, Marcel Dekker, Inc. New York, 1990).

The fluidizible silica-bound aggregate particles, like the silica bound extrudates described above, would then undergo the final step described below to convert the silica binder to an active material binder.

100891 The key step of this embodiment of the method is the conversion of the silica binder present in the silica-bound active material composite to an active material binder to bind the active material composite core-shell particles together to form the composite inorganic structure of the invention.

The core-shell particles are thus held together without the use of a significant amount of non-active material binder. The newly-formed active material binder is, when a molecular sieve e.g. MFI zeolite is produced in crystalline form. The crystals may have grown on and/or from the shell layer of the composite core-shell material.

100901 Catalytically active sites may be incorporated in the molecular sieve film of the structure, for example by selecting as the additional material a zeolite with a finite Si02:A1203 ratio, preferably lower than 300. The strength of these sites may also be tailored by ion-exchange. The structure may also be steamed, or treated in other manners known per Se, to adjust properties.

100911 The composite inorganic structures of the present invention may be used in the form of an extrudate with binder, in which the composite inorganic structure may be dispersed within a conventional binder. They are typically bound by forming a composite binder aggregate such as a pill, sphere, or extrudate. The extrudate is usually formed by extruding the inorganic composite structures in the presence of a binder and drying and calcining the resulting extrudate. The binder -21 -materials used are resistant to the temperatures and other conditions, e.g., mechanical attrition, which occur in various chemical or petrochemical processes such as hydrocarbon conversion processes.

Examples of binder materials include amorphous materials such as alumina, silica, titania, and various types of clays.

10092] The composite inorganic structures of the present invention, particularly but not exclusively in the form of pills, spheres or extrudates with or without conventional binder find particular application in hydrocarbon conversion processes and adsorption or separation processes. Examples of preferred processes include hydrocarbon conversion process where reduced non-selective acidity is important for reaction selectivity and/or the maintenance of catalyst activity, such as alkylation, dealkylation, disproportionation, and transalkylation reactions. The conversion of hydrocarbon feeds can take place in any convenient mode, for example, in fluidized bed, moving bed, or fixed bed reactors depending on the types of process desired. Examples of hydrocarbon conversion processes include, as non-limiting examples, the following: 100931 (A) The catalytic cracking of a naphtha feed to produce light olefins. Typical reaction conditions include temperature of from about 500°C to about 750°C, pressures of subatmospheric or atmospheric, generally ranging up to about 1.01 Mpa (10 atmospheres) gauge and residence time (volume of the catalyst feed rate) from about 10 milliseconds to about 10 seconds.

100941 (B) The catalytic cracking of high molecular weight hydrocarbons to lower molecular weight hydrocarbons. Typical reaction conditions for catalytic cracking include temperatures of from about 400°C to about 700°C, pressures of from about 10.1 kpa (0.1 atmosphere)to about 3.04 MPa (30 atmospheres), and weight hourly space velocities of from about 0.1 to about 100 hr'.

100951 (C) The transalkylation of aromatic hydrocarbons in the presence of polyalkylaromatic hydrocarbons. Typical reaction conditions include a temperature of from about 200°C to about 500°C, a pressure of from about atmospheric to about 20.3 MPa (200 atmospheres), a weight hourly space velocity of from about Ito about 100 hf' and an aromatic hydrocarbon/polyalkylaromatic hydrocarbon mole ratio of from about 0.5/I to about 16/1.

100961 (D) The isomerization of aromatic (e.g., xylene) feedstock components. Typical reaction conditions for such include a temperature of from about 230°C to about 5 10°C, a pressure of from about 51 kPa (0.5 atmospheres) to about 5.1 MPa (50 atmospheres), a weight hourly space velocity of from about 0.1 to about 200 hr and a hydrogen /hydrocarbon mole ratio of from about 0 to about 100.

10097] (E) The dewaxing of hydrocarbons by selectively removing straight chain paraffins. The reaction conditions are dependent in large measure on the feed used and upon the desired pour point. 22 -

Typical reaction conditions include a temperature between about 200°C and 450°C, a pressure up to 20.7 MPag (3,000 psig) and a liquid hourly space velocity from 0.1 to 20.

100981 (F) The alkylation of aromatic hydrocarbons, e. g., benzene and alkylbenzenes, in the presence olan alkylating agent, e. g, olefins, formaldehyde, alkyl halides and alcohols having I to about 20 carbon atoms. Typical reaction conditions include a temperature of from about 100°C to about 500°C, a pressure of from about atmospheric to about 20.3 MPa (200 atmospheres), a weight hourly space velocity of from about lhr1 to about lOOhr' and an aromatic hydrocarbon/alkylating agent mole ratio of from about I/I to about 20/1.

100991 (G) The alkylation of aromatic hydrocarbons, e. g., benzene, with long chain olefins, c. g., C14 olefin. Typical reaction conditions include a temperature of from about 50°C to about 200°C, a pressure of from about atmospheric to about 20.3 MPa (200 atmospheres), a weight hourly space VCI0L1L UI 110111 dUOUL LIII LU 400UL LUUVIII dilU dli dIUI1IdLI riyuiocuruoiiioieiii iiioie 14L10 UI 110111 about I/I to about 20/I. The resulting products from the reaction are long chain alkyl aromatics which when subsequently sulfonated have particular application as synthetic detergents.

101001 (H) The alkylation of aromatic hydrocarbons with light olefins to provide short chain alkyl aromatic compounds, e. g., the alkylation of benzene with propylene to provide cumene or with butene to provide sec. butyl benzene. Typical reaction conditions include a temperature of from about 10°C to about 200°C, a pressure of from about 101 kPa to 30.4 MPa (Ito 30 atmospheres), and an aromatic hydrocarbon weight hourly space velocity (WHSV) of from IhrT to about SOhr'.

101011 (1) The hydrocracking of heavy petroleum feedstocks, cyclic stocks, and other hydrocrack charge stocks. The catalyst will contain an effective amount of at least one hydrogenation component of the type employed in hydrocracking catalysts.

101021 (J) The alkylation of a reformate containing substantial quantities of benzene and toluene with fuel gas containing short chain olefins (e. g., ethylene and propylene) to produce mono-and dialkylates. Preferred reaction conditions include temperatures from about 100°C to about 250°C, a pressure of from about 690 kPag to 5.5 MPag (100 to about 800 psig), a WHSV-olefin from about 0.4hr to about 0.8hr', a WHSV-reformate of from about lh(1 to about 2hr' and, optionally, a gas recycle from about I.5 to 2.5 vol/vol fuel gas feed.

101031 (K) The alkylation of aromatic hydrocarbons, e. g., benzene, toluene, xylene, and naphthalene, with long chain olefins, e. g C14 olefin, to produce alkylated aromatic lube base stocks Typical reaction conditions include temperatures from about 160°C to about 260°C and pressures from about 2.41 kPag to 3.10 MPag (350 to 450 psig).

-23 - 10104] (L) The alkylation of phenols with olefins or equivalent alcohols to provide long chain alkyl phenols. Typical reaction conditions include temperatures from about 100°C to about 250°C, pressures from about 6.9 kPag to 2.07 MPag (1 to 300 psig) and total WHSV of from about 2hr1 to about IOhr'.

101051 (M) The conversion of light paraffins to olelins and/or aromatics. Typical reaction conditions include temperatures from about 425°C to about 760°C and pressures from about 69 kPag to 13.79 MPag (10 to about 2000 psig). Processes for preparing aromatic compounds from light paraffins are described in United States Patent 5,258,563, which is hereby incorporated by reference.

f0106] (N) The conversion of light olcfins to gasoline, distillate and lube range hydrocarbons.

Typical reaction conditions include temperatures of from about 175°C to about 375°C and a pressure of from about 690 kPag to 13.79 MPag(I00 to about 2000 psig).

I.f__._J_LJ_.L__.

tUtU / I I wo-sLage IyulolcKKIlIg 101 upglciulilg iiyuioar 0011 SUC4IIIS iidviiig IiIILIai UolllII points above about 200°C to premium distillate and gasoline boiling range products or as feed to further fuels or chemicals. In a first stage, the composites of the invention are used as catalysts comprising one or more catalytically active substances, for example a Group VIII metal, and the effluent from the first stage is reacted in a second stage using a second zeolite catalyst, e. g., zeolite Beta, comprising one or more catalytically active substances, for example a Group VIII metal.

Typical reaction conditions include temperatures from about 3 15°C to about 455°C, a pressure from about 2.76 to I 7.24 MPag (400 to 2500 psig), hydrogen circulation of from about I 78 to I 780 m3/m3 (1000 to about 10,000 SCF/bbl) and a liquid hourly space velocity (LHSV) of from about 0.1 to 10.

101081 (P) A combination hydrocracking/ dewaxing process in the presence of the zeolite bound zeolite catalyst comprising a hydrogenation metal and a zeolite such as zeolite Beta. Typical reaction conditions include temperatures from about 3 50°C to about 400°C, pressures from about 9.6 to 10.7 Mpag (1400 to about 1500 psig), Ll-ISVs from about 0.4 to about 0.6 and a hydrogen circulation from about 534 to 890 m3/m3 (3000 to about 5000 SCF/bbl).

(0109] (Q) The reaction of alcohols with olefins to produce mixed ethers, e. g., the reaction of methanol with isobutene and/or isopentene to provide methyl-t-butyl ether (MTBE) and/ort-amyl methyl ether (TAME). Typical conversion conditions include temperatures from about 20°C to about 200°C, pressures from 203 kPa to 20.3 MPa(2 to 200 atm), WHSV (gram olelin per hour gram-zeolite) from about 0.lhr1 to about 200hr' and an alcohol to olefin molar feed ratio from about 0.1/1 to about 5/1.

101101 (R) The disproportionation of aromatics, e. g., the disproportionation of toluene, to make benzene and paraxylene. Typical reaction conditions include a temperature of from about 200°C to -24 -about 760°C, a pressure of from about atmospheric to about 6.08 MPa (60 atmosphere) and a WHSV of from about 0.lhr to about 3Ohr* 10111] (S) The conversion of naphtha (e. g. C6-C10) and similar mixtures to highly aromatic mixtures. Thus, normal and slightly branched chained hydrocarbons, preferably having a boiling range above about 40°C, and less than about 200°C, can be converted to products having a substantial higher octane aromatics content by contacting the hydrocarbon feed with the composites of the present invention at a temperature in the range of from about 400°C to 600°C, preferably 480°C to 550°C at pressures ranging from atmospheric to 4 MPa (40 bar), and liquid hourly space velocities (LI-iSV) ranging from 0.1 to 15.

101121 (T) Selectively separating hydrocarbons by adsorption of the hydrocarbons. Examples of hydrocarbon separation include xylene isomer separation and separating olefins from a feed stream containing oiefiiis and parailins.

101131 (U) The conversion of oxygenates, e. g. alcohols, such as methanol, or ethers, such as dimethylether, or mixtures thereof to hydrocarbons including olefins and aromatics with reaction conditions including a temperature of from about 275°C to about 600°C, a pressure of from about 51 kPa to 5.IMPa (0.5 atmosphere to about 50 atmospheres) and a liquid hourly space velocity of from about 0.1 to about 100.

101141 (V) The oligomerization of straight and branched chain olefins having from about 2 to about 5 carbon atoms. The oligomers which are the products of the process are medium to heavy oleuins which are useful for both fuels, i.e. gasoline or a gasoline blending stock, and chemicals. The oligomerization process is generally carried out by contacting the olefin feedstock in a gaseous phase state with a catalyst at a temperature in the range of from about 250°C to about 800°C, a LHSV of from about 0.2 to about 50 and a hydrocarbon partial pressure of from about 10.1 kPa to 5.1 MPa (0.1 to about 50 atmospheres). Temperatures below about 250°C may be used to oligomerize the feedstock when the feedstock is in the liquid phase when contacting the zeolite catalyst. Thus, when the olefin feedstock contacts the catalyst in the liquid phase, temperatures of from about 10°C to about 250°C may be used.

101151 (W) The conversion of C2 unsaturated hydrocarbons (ethylene and/or acetylene) to aliphatic C6.i2 aldehydes and converting said aldehydes to the corresponding C612 alcohols, acids, or esters. In general, the catalytic conversion conditions include a temperature of from about 100°C to about 760°C, a pressure of from about 10.1 kPa to 20.3 MPa (0.1 to 200 atmospheres) and a weight hourly space velocity of from about 0.08hr' to about 2,000hr'.

-25 - 101161 Processes that find particular application using the composite inorganic structure catalysts of the present invention are those where two or more reactions are taking place within the composite structure catalyst. Each of the active materials of this catalyst would be separately tailored to promote or inhibit different reactions. A process using such a catalyst benefits not only from greater apparent catalyst activity, greater catalyst accessibility, and reduced non-selective surface acidity possible with such catalysts, but also from the possibility to obtain tailored catalyst systems.

101171 The present invention is further described by way olthe following examples. These examples are intended to illustrate or be representative of the invention and are not in any way intended to limit its scope.

EXAMPLE I

L'T'T'T (UI IOj VICdIdLIOJI vi au uuiuigiiic couuiposie uiaving d coie sneiu strueture 01 LA L LCO11LC core dilU MFI zeolite shell layer.

(01191 LTL zeolite crystals were prepared from two solutions having the following compositions.

10120] Solution A comprised 178.13 gofKOl-1 [87.5%],40.87gAl(Ol-l)3 [99.3%] and 301.63 g of water.

101211 Solution B comprised 0.2052 g of Mg(N03)2.6H20 in 130.0 g of water.

101221 The synthesis was carried out by mixing 784.17 g of Ludox HS4O (a colloidal silica sol which is supplied byW.R. Grace Davison comprising 4Owt% Si02 and 60% H20) with 442.00 g of water. Solution B was added to this mixture and mixed. 43.20 g of water was used to rinse the solution B container. This water was added to the mixture. The mixture was stirred for another 5 minutes. To this mixture was added solution A using 78.04 gof rinse water. The resulting mixture was stirred for 2 minutes before it was transferred to a 2 liter stainless steel autoclave. The autoclave was heated to 1 70 C over a period of 9 hours and 40 minutes and was kept at this temperature for 96 hrs. After cooling the crystals were separated from the mother liquor and washed with water.

101231 MFI zeolite (molar composition: lOSiO2/0.54Na2O/3.O3TPAOH/150H20) was prepared as follows: 1587.71g of tetrapropylammonium hydroxide [TPAOH] (20% in water, Fluka brand, as supplied by Sigma-Aldrich Corporation) was poured in a glass beaker. Then, 22.47 l2g NaOH (98.7%, Mallinckrodt Baker, Inc.) was added and stirred until it was completely dissolved To the solution was added 352.OOg silicic acid (89.80%, as supplied by Mallinckrodt Baker, Inc.) and the resulting mixture was heated to boiling while stirring. The mixture was allowed to boil until the silicic acid was completely dissolved. Thereafter the solution was allowed to cool down and water was added to -26 -compensate for water loss during boiling. The resulting synthesis mixture was poured into a polypropylene bottle and heated during boiling under reflux for 29 days at 50°C in an oil bath. After the synthesis, the material was washed using a high speed centrifuge until the pH of the wash water was below 1 0 101241 1.04 g of LTL zeolite crystals prepared as described above were weighed on a Whatman 42 filter paper, which was then formed into a cone. These LTL zeolite crystals were treated with 12.07 g of cationic polymer solution (Redifloc 4150, 0.4 wt% and pH 8) by pouring the cationic polymer solution into the filter paper cone and allowing the liquor to pass over the LTL zeolite crystals and through the filter paper. The treated LTL zeolite crystals were washed three times with separate 1 5 g aliquots of 0.IN N1-L1OH to remove excess cationic polymer.

101251 The washed LTL zeolite crystals were treated with 10.0 g of a colloidal suspension of the ___:LL.. I... ......_: iviri LCUULC LUIIUIUc1I i.r)'st4is LIIdL IldU UCCII pIvpaIvu as ucss..jivcu 4UUVC, uy puuulng uic uiiuiua suspension into the filter paper and allowing it to pass over the washed LTL zeolite crystals and through the filter paper. The resultant powder was washed three times with 15 g of 0.IN N1-140H and the washed powder was dried on the filter paper overnight at 120°C.

[0126] The resultant product was an inorganic composite having a core-shell structure comprising a core of LTL zcolite with a thin shell layer of MFI zeolite particles.

EXAMPLE 2

101271 Preparation of a composite inorganic structure using the inorganic composite having a core-shell structure as prepared in Example 1.

101281 1.00 g of the inorganic composite having a core-shell structure of Example I was mixed in a 25 ml Teflon� lined Parr� autoclave with 5.00 g of an MFI synthesis mixture (molar ratios: IOSiO2 0.22Na2O: 0.52 TPABr: 283 H20) . This mixture had been prepared as follows: to a solution of 0.318 gofNaOH [98.6% as supplied by Mallinckrodt Baker, Inc.] in 73.81 g of water, was added 2.46 g of tetrapropylammonium bromide (TPABr) [Fluka purum, as supplied by Sigma-Aldrich Corporation]. To this solution was added 26.53 g of Ludox AS4O [40% of Si02 as supplied by W.R.

Grace Davison]. This mixture was stirred for 2 minutes. The closed autoclave was placed into an oven and the temperature was raised steadily Irom room temperature to 90°C over a period of 30 minutes. The oven was held at this temperature for 36 hours and then allowed to cool to room temperature.

101291 When the autoclave was opened there was a bluish liquor and powder at the bottom of the liquor. The powder was washed with water and dried.

-27 - [0130] The resultant product was analyzed using a scanning electron microscope and the resultant SEM is shown in Figure 1. This showed that the core LTL zeolite crystals were now covered with a continuous layer of MFI zeolite.

EXAMPLE 3

101311 Preparation of an inorganic composite having a core-shell structure of FAU zeolite core and silicalite-l shell layer.

101321 FAU zeolite crystals were prepared according to a standard procedure described in the section "High-silica Faujasite EMC-l" in Verified Synthesis of Zeolite Materials" published on behalf of the international Zeolite Association, H. Robson Ed., Second Edition page 159, Elsevier 2001.

Fn111 I _..l. --I.UU g UI t%U LCUIILC LISL4IS WR SU4IWU III d (.dIIUIIII. poiyiiii SUIULIUII i1'CUUIU'.. t I..flJ, 0.4 wt% and pH 8) with stirring for 5 minutes. The solution with FAU zeolite crystals was then centrifuged for 15 minutes at 3500 rpm in a bench top centrifuge (Heraeus Labofuge 400). After centrifugation the slightly hazy liquor was decanted and the powder was washed 3 times with centrifugation (15 mins @3500 rpm) with 0.IN NH4OI-l. The washed polymer treated FAU crystals were soaked in 10.00 g of a colloidal suspension of silicalite-l colloidal particles (1 wt% and an average particle size about 50 nm, as measured by scanning electron microscopy) for 15 minutes.

The suspension containing the FAU crystals was then centrifuged for 15 minutes at 3500 rpm and the powder that resulted after decanting of the liquor was washed 3 times with centrifugation (IS mins @ 3500 rpm) with 0.1 N NH4OH.

101341 The resultant product was an inorganic composite having a core-shell structure comprising a core of FAU zeolite with a thin shell layer of silicalite-1 particles having an average particle size of approx. 50 nm, as measured by scanning electron microscopy.

EXAMPLE 4

[0135] Preparation of a composite inorganic structure using the inorganic composite having a core-shell structure as prepared in Example 3.

101361 A ZSM-5 synthesis mixture of molar composition: lOSiO2/0.125A1203/0.45Na2O/0.9OTPABr/146H20, I9wt ppm seeds was prepared as follows: 4.67g ofNaOH (98.7%, Mallinckrodt Baker, Inc.), 2.53g of hydrated alumina (ALCOA, 98.5%) and 14.82g H20 were stirred and boiled until a clear solution was obtained. The solution was allowed to cool down and water was added to compensate for the water loss during heating. Then 30.67g TPABr (Fluka purum, as supplied by Sigma-Aldrich Corporation) was dissolved in 125 67g H20 and the resulting solution was added to 191.89g Ludox HS-40 (a colloidal silica sol which is supplied by W.R. Grace Davison comprising 40 wt% Si02 and 60 wt% H20) in a glass beaker.

Remaining solution was rinsed into the beaker with 65.27g H20 and the contents of the beaker was mixed for 2 minutes using a lab stirrer with fixed blades. 0.0488g colloidal (SOnm) silicalite-1 seeds (0. 1 7525 wt%) was mixed into the beaker for 2 minutes using a laboratory stirrer with fixed blades.

Thereafter, the NaOH/hydrated alum inafH2O mixture was added to the TPABr/Ludox HS-40 mixture and mixed for 10 minutes using a laboratory stirrer with fixed blades. I'he synthesis mixture was stored in a plastic bottle.

101371 0.44 g of the inorganic composite having a core-shell structure of Example 3 was mixed with 2.53 g of the ZSM-5 synthesis mixture (prepared as described above) in a 25 ml Teflon� lined I.____. ___:_x__iI r4u 4utuLI2ve, wilil euiitiiiuous stiiiing 101 I iiuui. iii LIUSCU 4UL0IVC W4S piacu IIILO au UVCII and the temperature raised steadily from room temperature to 150°C over a period of 2 hours. The oven was held at this temperature for 16 hours and then allowed to cool to room temperature.

f0138J The resultant product was analyzed using a scanning electron microscope and the resultant SEM is shown in Figure 2. This showed that the core FAU zeolite crystals were now covered with a continuous layer of ZSM-5 zeolite.

EXAMPLES

101391 Preparation of an inorganic composite having a core-shell structure of ZSM-48 zeolite core and silicalite-l shell layer.

[0140) ZSM-48 zeolite crystals were prepared by the following method.

101411 A solution was prepared by combining 0.71 g of A12(S04)3.l81-120, 5.75 g of NaOH [98.7%], and 34.91 g of 1,6 diaminohexane in 428.78 g of water. This solution was added to 148.14 g of Ludox AS4O (4Owt % silica in water,W.R. Grace Davison) and mixed for 5 minutes. 163.29 g of water was used to rinse the container used for starting solution and this water was added to the mixture. To this homogeneous mixture were added 3.028 g of a 0.25 wt% slurry of colloidal zeolite Beta seeds prepared according to EP-A-609304. The resulting mixture was mixed for another 5 minutes before being transferred to a I liter stainless steel autoclave. The autoclave was heated over a period of 2 hrs to 150 C and was kept at this temperature for 40 hrs. After cooling the crystals were separated from the mother liquor and washed with water.

(01421 2 00 g ofZSM-48 zeolite crystals were dispersed in a cationic polymer solution (100 ml, 5 wt% Redifloc 4150 and pH 8) with ultra-sonication. The solution with ZSM-48 zeolite crystals was -29 -then centrifuged for 15 minutes at 3500 rpm in a bench top centrifuge (Heraeus Labofuge 400). After centrifugation the clear supematant was decanted and the powder was redispersed in 125 ml of 0.IN NH4OH in an ultrasonic bath for 10 minutes. This redispersed powder was centrifuged for 15 minutes at 3500 rpm and the clear supernatant was decanted. The redispersion and centrifugation was repeated a further two times. 100 ml of a colloidal suspension of silicalite-I colloidal particles (7.24 wt% and an average particle size about 50 nm as measured by scanning electron microscopy) was added to the powder and mixed for 15 minutes. This suspension was then centrifuged for 15 minutes at 3500 rpm after which the supernatant was still milk white suggesting that excess colloidal seeds had been present in this treatment stage. The supernatant was decanted and the powder was redispersed in 125 ml of0.IN NH4OI-! stirred using a magnetic stirrer for 10 minutes, followed by centrifugation for 15 minutes at 3500 rpm after which the supernatant (still hazy) was decanted.

These redispersion and centrifugation steps were repeated a further 4 times until the final wash water was clear. The resultant washed powder was dried in an oven at 120°C.

101431 The resultant product was an inorganic composite having a core-shell structure comprising a core of ZSM-48 zeolite with a thin shell layer of silicalite-l particles having an average particle size of approximately 50 nm as measured by SEM

EXAMPLE 6

[01441 Preparation of a composite inorganic structure using the inorganic composite having a core-shell structure as prepared in Example 5.

101451 1.00 g of the inorganic composite having a core-shell structure of ExampleS was mixed in an 25 ml Teflon� lined with Parr� autoclave with 10.00 g of a ZSM-5 synthesis mixture (molar ratios: lOSiO2: 0.22Na2O: 0.52 TPABr: 200 H20). This synthesis mixture was prepared in the following way: to a solution of 0.887 g of NaOH (98.6% as supplied by Mallinckrodt Baker, Inc.] in 133.32 g of water, was added 6.84 g of tetrapropylammonium bromide [Fluka purum, as supplied by Sigma-Aldrich Corporation]. To this solution was added 74.03 g of Ludox AS4O [as supplied by W.R. Grace Division]. This mixture was stirred for 2 minutes. The closed autoclave was placed into an oven and the temperature raised steadily from room temperature to 90°C over a period of 30 minutes. The oven was held at this temperature for 18 hours and then allowed to cool to room temperature.

101461 The autoclave was opened to reveal a white liquor with a layer of settled yellow crystals on the bottom. The resultant product was analyzed using a scanning electron microscope and the -30 -resultant SEM is shown in Figure 3. This showed that the core ZSM-48 zeolite crystals were now covered with a continuous layer of ZSM-5 zeolite.

EXAMPLE 7

101471 Preparation of an inorganic composite having a core-shell structure of ZSM-23 zeolite core and silicalite-l shell layer.

101481 29.83 g of ZSM-2 3 zeolite crystals were dispersed in a cationic polymer solution (250,14g, wt% Redifloc 4150 and p1-1 8) for 10 minutes. The ZSM-23 zeolite comprised agglomerates of near-spherical morphology and approximately 5000 nm (5 rim) diameter. A typical method for production of ZSM-23 is given in US-A-4076842. The solution containing ZSM-23 zeolite crystals was then centrifuged for 15 minutes at 3500 rpm in a bench top centrifuge (Heraeus Cryofuge Classic). After centrifugation the supernalant was decanted and the powder was redispersed in 250 ml of 0.IN NH4OH with stirring for 10 minutes. This redispersed powder was centrifuged for 15 minutes at 3500 rpm and the clear supernatant was decanted. The redispersion and centrifugation was repeated a further two times. The powder was then dispersed in 100 ml of a colloidal suspension of silicalite-l colloidal particles (32.8 wt% of unwashed silicalite-l seeds in the slurry) for 10 minutes. This suspension was then centrifuged for 15 minutes at 3500 rpm after which the supernatant was still milk white and was decanted. The powder was washed three times using redispersion in 250 ml of0.lN NH4OH with stirring for 0 minutes followed be centrifugation for IS minutes at 3500 rpm, with decantation of the supernatant between washing cycles. The resultant powder was dried overnight in an oven at 120°C.

101491 The resultant product was an inorganic composite having a core-shell structure comprising a core of ZSM-23 zeolite with a thin shell layer of silicalite-1 particles having an average particle size of approx. 50 nm as measured by scanning electron microscopy.

EXAMPLE 8

(0150] Preparation of a composite inorganic structure using the inorganic composite having a core-shell structure as prepared in Example 7.

10151] 1.45 g of the inorganic composite having a core shell structure of Example 7 was mixed with 5.03 g of a ZSM-5 synthesis mixture (molar ratios: IOSiO2: 0.22Na2O: 0.52 TPABr: 200 1-120) in a 25 ml Teflon� lined Parr� autoclave. The ZSM-5 synthesis mixture had been prepared as described in Example 6. The closed autoclave was placed into an oven and the temperature raised steadily from room temperature to 175°C over a period of 30 minutes. The oven was held at this temperature for 1 hour and then allowed to cool to room temperature.

101521 The autoclave was opened to reveal a solid yellow gel with a small amount of water on top with no free water after stirring. Centrifugation for 30 minutes at 3500 rpm provided a top liquor which was brownish in colour and slightly hazy. The resultant solid product was separated and analyzed using a scanning electron microscope and the resultant SEM is shown in Figure 4. This showed that the core ZSM-23 zeolite crystals were now covered with a continuous layer of ZSM-5 zeo I ite.

EXAMPLE 9-SAMPLE A

f0153] Preparation ola composite inorganic structure using the inorganic composite having a core-shell structure as prepared according to Example 3.

[0154J 1.00 g of the inorganic composite having a core-shell structure prepared according to the procedure of Example 3 was mixed with 10.00 g of a ZSM-5 synthesis mixture (molar ratios: lOSiO2 15: 0.22Na2O: 0.52 TPABr: 200 H20) in a 25 ml Teflon� lined Parr� autoclave. The ZSM-5 synthesis mixture had been prepared as described in Example 6. The closed autoclave was placed into an oven and the temperature raised steadily from room temperature to 1 75°C over a period of 30 minutes.

The oven was held at a temperature of 175°C for a period of 10 hours and then allowed to cool to room temperature. The resultant product was washed to a wash water pH of below 10.

101551 The product was analyzed using a scanning electron microscope and XRD. The resultant SEM is shown in Figure 5 and XRD in Figure 6. The XRD showed that the product was crystalline and had a FAU and MFI pattern. The SEM showed that there was an MFI shell of some 100 nm or greater thickness around a FAU core. The left hand SEM of Figure 5 shows some exposed FAU surfaces where agglomerates were broken during SEM sample preparation; otherwise the surface of the FAU is covered with MFI. Some free MFI "coffins" may also be seen. The right hand SEM shows the MFI shell, several hundred nm thick, on the FAU surface.

101561 The product had an n-hexane adsorption capacity of 14.70%.

EXAMPLE 10-SAMPLE B

(0157j Preparation of a composite inorganic structure using the inorganic composite having a core-shell structure as prepared according to Example 3.

101581 2.00 g of the inorganic composite having a core-shell structure prepared according to the procedure of Example 3 was mixed in a 25 ml Teflon� lined Parr� autoclave with 10.00 g of a ZSM- -32 -synthesis mixture (molar ratios: lOSiO2: 0.22Na2O: 0.52 TPABr: 200 H20). The ZSM-5 synthesis mixture had been prepared as described in Example 6. The closed autoclave was placed into an oven and the temperature raised steadily from room temperature to 175°C over a period of 30 minutes.

The oven was held at a temperature of 175°C for a period of 4 hours and then allowed to cool to room temperature. The resultant product was washed to a wash water pH of below 10.

101591 The resultant product was analyzed using a scanning electron microscope and XRD. The resultant SEM is shown in Figure 7 and XR.D in Figure 8 The XRD showed that the product was crystalline and had a FAU and MFI pattern. The product of this Example had a thinner layer of ZSM-5 (MFI) coating than that of Example 9. i'he left hand SEM shows incomplete coverage of the JO FAU core by MFI shell material, and the right hand SEM shows an FAU edge without MF1 coverage, and isolated MFI crystals on the FAU surface 101601 Tue product had an n-hexaiie adsorption capacity of 10.99%.

EXAMPLE 11 -SAMPLE C 101611 Preparation of a composite inorganic structure using the inorganic composite having a core-shell structure as prepared according to Example 3.

101621 22.9 g of the inorganic composite having a core-shell structure prepared according to the procedure of Example 3 was mixed with 20.00 g of a ZSM-5 synthesis mixture (molar ratios: IOSiO2 0.22Na2O: 0.52 TPABr: 200 H20) and 1.00 g Aerosil� 300 in a Haake Rheomix 30 rpm. Aerosi1 300 is a silica source containing at least 99.8 wt% Si02, supplied by Degussa GmbH. An extra 1.00 g of Aerosil� 300 was added to the mix as it was still too fluid for extrusion. The mixture was mixed For 15 minutes. The resultant paste was extruded through a 1 mm die using a piston extruder. The paste dewatered during extrusion. After extrusion all the material including water was remixed and fed back through the extruder. The sample was again dewatered but to a lower degree. The extrudate was then allowed to dry.

101631 1.1 7g of the dried extrudate was soaked under vacuum in 10.00 g of a synthesis solution made by adding 12.5 g of tetraethyl orthosilicate [98% as supplied by Sigma-Aldrich Corporation.] to a solution containing 7.37 g of tetrapropyl ammonium hydroxide [Fluka, 20% in water, as supplied by Sigma-Aldrich Corporation] in 56 89 g of water. This mixture was stirred for 24 hours at room temperature.The composition thus formed was placed in a 25 ml Teflon� lined Parr� autoclave.

The closed autoclave was placed into an oven and the temperature raised steadily from room temperature to 175°C over a period of 30 minutes. The oven was held ata temperature of 175°C for a -33 -period of 10 hours and then allowed to cool to room temperature. The resultant product was washed in hot de-ionized water until the conductivity of the wash water was below 50 iS/cm.

101641 The resultant product was analyzed using a scanning electron microscope and the resultant SEM is shown in Figure 9. The silica in the extrudate was converted to silicalite-l. The XRD showed that the product was crystalline and had a FAU and MFI pattern. The SEM showed that MFI was present in the treated extrudate.

101651 The product had an n-hexane adsorpflon capacity of 15.46%.

EXAMPLE 12 -Paraxylene selectivities 10166] This example shows the paraxylene selectivities of the composite inorganic structures prepared in samples A, B and C (Examples 9, 10 and 11) respectively compared to silicalite-l and NY LeoIIte.

(0167] The paraxylene (pX) selectivities compared to metaxylene (mX), orthoxylene (oX) and ethylbenzene (EB) were determined by static liquid phase adsorption experiments. Two samples of approximately 70 mg of powdered adsorbent were each calcined at 500°C in I mL glass sampling vials for 8 hours before cooling to below 250°C. The sample vials were capped with a suitable gas chromatograph (GC) septum at about this 250°C temperature in order to prevent hydration of the highly hygroscopic adsorbent. After cooling to room temperature approximately 215 mg of equilibrium aromatics feed (A8 feed containing pX, mX, oX and EB at equilibrium) that contained approximately 10 wt% triisopropylbenzene (TIPB) as internal standard was charged to the vials. The samples were introduced into stainless steel autoclaves, and the autoclaves were sealed with a septum and heated to 100°C for 1 hour. A portion of the liquid was collected by syringe, diluted and analyzed by GC. From the normalized area count for each component relative to TIPB the paraxylene (pX) selectivity of the adsorbent could be calculated using the following equations: = (pXz/pXL)/(nXz/nXI.) nX nX0 -nXL) = [(pXo -pXI}pXL)]/( nX0 -nXL/nXL) = (pXo/pXL-l)/(nXo/nXL-I) nX = part of component nX adsorbed in/on the sample.

nX0 amount of component nX present in unadsorbed feed.

nX.part of component nX in the bulk liquid after adsorption.

pX = paraxylene.

10168] The results of the static liquid phase adsorption analysis are shown in Figure 10 and Table -34 -

TABLE I

pX Selectivities displayed as ci (pXInX) values ci (pXIEB) ci (pXlmX) ci (pXIoX) NaY 1.12 0.66 0.83 Silicalite-l 0.93 3.13 3.45 SampleA 1.15 3.08 2.99 Sample B 137 1.77 1.75 Sample C 1.12 1.01 0.85 101691 The data show that the as synthesized NaY displayed moderate mX and oX selectivity as evidenced by alpha values (pX/nX) of< 1. The silicalite-l is highly selective for pX, due to preferential adsorption ofpX. Sample A displays high pX selectivity similar to that of pure silicalite- 1. Sample B with the incomplete coating does not result in enhanced pX selectivity. Sample C shows medium selectivity for pX.

EXAMPLE 13 -n-Hexane adsorption 101701 As reported in Examples 9, 10 and II, the composite inorganic structures of Examples 9, 10 and 11 (Samples A, B and C respectively) were characterized by scanning electron microscopy and XRD.

101711 The XRD results confirmed that each of Samples A, B and C was crystalline and had FAU and MFI pattern.

[0172] The SEM results allowed the following conclusions: Sample A: MFI shell of several hundred nm thickness around an FAU core.

Sample B: incomplete/thin shell of MFI around an FAU core.

Sample C: MFI shell around FAU core with MFI present in the treated extrudate prepared using ZSM-5 synthesis mixture.

101731 The n-hexanc adsorption capacity of Sample A and also of pure Silicalite-1 and pure FAU was determined by a standard method using thermogravimetric analysis (TGA). The results for n-hexane adsorption capacity were: SampleA: 14.7Owt% Silicalite B: 10.99 wt% FAU: 15.45 wt% -35 - 10174] It is to he noted from Examples 12 and 13 that Sample A (a core-shell of FAU/silicate-1, onto which has been grown a ZSM-5 (MFI) shell or third layer") combines the properties of a very good adsorption capacity (14.70% for n-hexane) with a selectivity for pX comparable to silicalite -1.

It is believed that this preferred selectivity arises because the "third layer" of the structure functions as a selective membrane". Thus, it is postulated that the FAU/MFI composite structure provides a higher pX selective sorption capacity because the MFI layer acts as a pX selective membrane while the FAU core crystal provides a reservoir with increased capacity (as compared to MFI, which has a significantly lower sorption capacity than FAU). A similar performance may be expected regarding the adsorption capacity of sample C comprising a FAU core with silicalite -1 shell having further silicalite -1 "third layer" grown thereon.

101751 Without wishing to be bound by theory, it is believed that the sorption capacity of the structures as exemplified wili depend on the FAU/MF1 ratio of ihe structure. Tue ii-hexane sorption data follow the same trend as in the literature (for example. W. Makowski et al, Applied Surface Science 252 (2005) 707-715): FAU has a higher sorption capacity for n-hexane (approx I 7wt% IS reported in the Makowski et al article; approx. 15.5 wt% as measured in Example 13) than MFI (approx 10 wt% reported in the Makowski et al article; approx 11 wt% as measured in Example 13).

Thus the sorption value obtained for Sample A (14.70 wt%) is consistent with a large proportion of the pore volume of the structure being FAU.

EXAMPLE 14

101761 This Example describes the synthesis of a mixed metal oxide (perovskite) precursor of formula: (La06Cao4Feo 2Mno g03). Its use in the preparation of inorganic composite having a core-shell structure with ZSM-5 is described in Example 15 (comparison) and Example 16.

101771 The perovskite precursor was generally prepared by mixing sufficient quantities of water soluble metal ions in basic aqueous solution containing quaternary ammonium salts and Na2CO3 After precipitation and washing the precursor was calcined Ibr 6 hours at 800°C to effect crystallization.

101781 The following stock solutions were prepared.

IM Fe(N03)3.9H20 40.4 g/100 ml IM La(N03)3.6H20 43.3 g/l00 ml lM Ca(N03)2.4H20 23.62 g/100 ml IM Mn(N03)2.6H20 40.4 g/l00 ml [0179] The following solutions were prepared.

-36 -Solution A (Prepared in glass separation funnel).

6.15 g I M Fe(N03)3.9H20 = 1.77 g Fe(N03)3.9H20 = 0.24 g Fe 18.01 g IM La(N03)3.6H20 = 5.44 g La(N03)3.6H20 = 1.75 g La 25.90 g H20 Solution B (Prepared in glass separation funnel).

11.22 g I M Ca(NOi)3 91-120 = 2.14 g Ca(NOi)3.9H20 = 0.36 g Ca 22.82 g IM Mn(N03)3.6H20 = 5.09 g Mn(N03)3.6H20 = 0.97 g Mn 15.95 g I120 Solution C (Prepared in IL plastic bottle).

15.00 g NaHCO3 II t )UV.U'.) g fl2U 45.03 g TEAOI-1 35% 101801 Solution C was stirred vigorously using a magnetic stirrer. Solutions A and B were added drop wise to solution C over a period of 10 minutes followed by 1 hour of continuous stirring.

101811 The resulting mixture was transferred to a I L centrifuge bottle. The mixture was centrifuged for 10 mins @4000 rpm and the clear top liquor was decanted. The remaining material was redispersed in 750 ml 1-120 and placed in an ultrasonic bath for 1 5 mins. The mixture was centrifuged for 10 mins @4000 rpm and the clear top liquor was decanted. The remaining material was redispersed in 250 ml isopropanol and placed in an ultrasonic bath for IS mins. The mixture was centrifuged for 10 mins 4000 rpm and the clear top liquor was decanted. The remaining material was redispersed for a final time in 250 nil isopropanol and placed in an ultrasonic bath for 15 mins.

The mixture was centrifuged for 10 mins 4000 rpm and the clear top liquor was decanted. The remaining material was dried for 12 hours at 120°C and calcined at 800°C for 6 hours.

101821 The material was analyzed using X-ray diffractions (XRD) and scanning electron microscopy. The material was determined to be a microcrystalline perovskite mixed metal oxide with minor impurities of a second (unidentified) perovskite phase. The primary perovskite particles displayed a particle size of 100-200 nm. According to laser diffraction a bimodal particle size distribution is present in this sample stemming from the agglomeration of the primary perovskite particles. The sample was found to have a surface area of 12.5 m2/g by nitrogen physisorption The XRD pattern for this sample is shown in Figure 11 and the SEM is shown in Figure 12.

101831 An ultrasound technique was use in an attempt to disperse the perovskite particles in water.

However, the surface charge (zetapotential) of the perovskite particles was found to be a low positive -37 -value favoring agglomeration. The perovskite particles could be dispersed in water, however, with the aid of a cationic polymer and the use of ultrasound. The polymer employed was a quaternary amine polymer, Bewoten C410, supplied by Akzo Nobel. This was mixed with water to form a 0.2 wt% solution, which was brought to a pH value of 8 with 0.1 N NH4OH. 25 ml of the resulting solution were added to 0.3 g of the perovskite mixed metal oxide particles prepared as described above, to form a 1.2 wt % dispersion. The addition of the cationic polymer increased the surface charge of the perovskite particles giving strongly positive values for surface charge. Dispersion results showed that deagglomeration of the perovskite particles was achieved with addition of the cationic polymer. The increase of the surface charge on adhesion of the positively charged polymer onto the perovskite surface led to increased interparticle repulsion and stabilization of the dispersion.

rv A P. ,IFI r' 1 C EAl-%lv1rLL. 1.) 101841 I'he perovskite particles of Example 14 dispersed in water with cationic polymer were used in an attempt to prepare an inorganic composite having a core-shell structure with a ZSM-5 core.

IS 101851 The materials used in this Example were large crystal ZSM-5 prepared using a standard recipe (ZSM-5 particles of about 2000 nm [2 rim]) and the aqueous dispersion of perovskite particles treated with cationic polymer, prepared as described in Example 14. The large crystal ZSM-5 particles were added to the dispersion and then the solids were recovered by centrifugation. The isolated material was evaluated using a scanning electron microscope and the SEM is shown in Figure 13. This figure shows that the material consists of a physical mixture of perovskitc agglomerates and ZSM-5 zeolite crystals. The particles are not bound to each other in core-shell configuration as required for the structures according to the invention. It is believed that the perovskite particle dispersion had an excess of cationic polymer present which also affected the surface properties of the ZSM-5 crystals making it impossible for the perovskite particles to adhere (bond) to the surface of the ZSM-5 particles.

EXAMPLE 16

[01861 The perovskite particles of Example 14 dispersed in water with cationic polymer were used to prepare an inorganic composite having a core-shell structure with a ZSM-5 core.

101871 A sample of the aqueous dispersion of cationic polymer-treated perovskite particles that had been prepared as described in Example 14 was used as one of the starting materials. However, in contrast to Example 15, the dispersion was first centrifuged and the thus-separated perovskite particles were washed with NI-140H solution to remove excess polymer. The washed particles were -38 -then redispersed in water and the resulting despersion was used to treat a sample of the same ZSM-5 crystals as had been used in Example 15. The procedure of Example 15 was repeated and the resultingZSM-5/perovskte agglomerates were removed by centrifugation and calcined in order to remove the polymer and strengthen the zeolite/perovskite bonding. The isolated material was evaluated using a scanning electron microscope and the SEM is shown in Figure 14. The XRD analysis of the material is shown in Figure 15. The SEM shows that the product has an even shell layer of small perovskitc particles adhered to the surface of the ZSM-5 core crystal. The XRD pattern shows a mixture of perovskite and MFI with roughly 30% of the material being perovskite.

101881 This Example shows that by applying careful techniques an inorganic composite of core-shell structure can be prepared where the shell is mixed metal oxide. This composite can then be used as the starting point for applying an additional inorganic material by deposition onto and/or growth on and/or from the mixed metal oxide shell layer, to form a composite inorganic structure according to the invention. The application of the additional inorganic material (or "third layer') may be by, for example, the techniques demonstrated in Examples 2, 4, 6, 8, 9, 10 or II.

101891 While the present invention has been described and illustrated by reference to particular embodiments, those of ordinary skill in the art will appreciate that the invention lends itself to variations not necessarily illustrated herein. For this reason, then, reference should be made solely to the appended claims for purposes of determining the true scope of the present invention.

Claims (1)

1. -39 -

   1. A composite inorganic structure comprising (I) an inorganic composite having a core-shell structure, the core comprising particulate material and the shell layer comprising a plurality of particles and (ii) at least one additional inorganic material deposited upon andlor grown on and/or from the shell layer.

   2. The composite inorganic structure as claimed in claim I wherein the core particle comprises an organic material.

   3. The composite inorganic structure as claimed in claim 2 wherein the core particle is hollow 4. The composite inorganic structure as claimed in claim I wherein the core particle comprises JO an active material and the shell comprises material which is not active.

   5. The composite inorganic structure as claimed in claim I wherein the core is not an active material and the shell comprises active material.

   6, The composite inorganic structure as claimed in claim I wherein both the core and shell comprise active material.

   7. The composite Inorganic structure as claimed in claim I wherein the core comprises molecular sieve.

   8. The composite inorganic structure as claimed in claim I wherein the shell comprises molecular sieve.

   9. The composite inorganic structure as claimed in claim I wherein the shell comprises one or more metal oxides.

   10. The composite inorganic structure as claimed in claim 9 wherein the shell comprises one or more mixed metal oxides.

   11. The composite inorganic structure as claimed in claim 9 or 10 wherein the metal oxide or mixed metal oxide comprises one or more of the oxides of Fe, Ca, Mn and La.

   12. The composite inorganic structure as claimed in claim 10 or II wherein the mixed metal oxide comprises one or more mixed metal oxides of perovskite structure.

   13. The composite inorganic structure as claimed in claim 7 or 8 wherein the molecular sieve is a zeolite 14. The composite inorganic structure as claimed in claim 13 wherein the zeolite is one or more ofZSM-5, ZSM-23, ZSM-48, FAU zeolite, LTL zeolite, silicalite-l and members of the MCM-22 family.

   IS. The composite inorganic structure as claimed in any one the preceding claims wherein the shell layer comprises colloidal particles.

   -40 - 16. The composite inorganic structure as claimed in any one of the preceding claims wherein the shell layer has a thickness of in the range of from 10 to 2000 nm.

   17. The composite inorganic structure as claimed in any one of the preceding claims wherein the core has an average particle size in the range of from 100 to 5000 nm.

   18. The composite inorganic structure as claimed in any one of the preceding claims wherein the shell particles have an average particle size in the range of from Ito 300 nm.

   19. The composite inorganic structure as claimed in claim 1 8 wherein the shell particles have an average particle size in the range of from 5 to 150 nm.

   20. The composite inorganic structure as claimed in any one of the preceding claims wherein the additional inorganic material comprises inorganic material of the same material type as material of the shell layer.

   21. The composite inorganic structure as caimed in any one of claims ito 19 wherein the additional inorganic material comprises inorganic material of a material type that is different from that of material of the shell layer.

   22. The composite inorganic structure as claimed in any one of the preceding claims wherein the additional inorganic material comprises active inorganic material.

   23. The composite inorganic structure as claimed in any one of the preceding claims wherein the additional inorganic material comprises molecular sieve.

   24. The composite inorganic structure as claimed in any one of claims Ito 22 wherein the additional inorganic material deposited on the shell layer comprises mixed metal oxide.

   25. The composite inorganic structure as claimed in any one of the preceding claims, wherein the additional inorganic material is in the form of a shell layer around the inorganic composite.

   26 The composite inorganic structure as claimed in any one of claims I to 24 wherein the additional inorganic material comprises an inorganic matrix.

   27. The composite inorganic structure as claimed in claim 26 wherein the inorganic matrix comprises active inorganic material.

   28. the composite inorganic structure as claimed in claim 26 wherein the inorganic matrix is free of active material.

   29. The composite material as claimed in claim 26 wherein the inorganic matrix comprises precursors to an active inorganic material.

   30. The composite material as claimed in any preceding claim wherein the additional inorganic material is of a thickness in the range of from 100 to 150000 nm. -41 -

   31 A method for the manufacture of a composite inorganic structure, which method comprises (a) providing an inorganic composite having a core-shell structure prepared by (I) treating (I) a particulate core precursor material A andlor (ii) a plurality of particles of one or more inorganic shell precursor materials B, so as to induce a change in the surface charge of the particles of A andlor B such that the particulatecore precursor A has an opposite surface charge from that of the particles of shell precursor material(s) B and (II) bringing the oppority charged particles of A and B into contact with each other under conditions such that the particles of inorganic shell precursor material(s) B become bonded to the surface of the particulate core precursor material A to form the inorganic composite having a core-shell structure, (b) providing a precursor to an additional inorganic material, and (c) contacting and/or treating the inorganic composite provided in (a) and the precursor provided in (b) under such conditions that additional inorganic material is deposited upon and/or grown onto or from the shell layer of the inorganic composite.

   32. The method as claimed in claim 3 1 wherein the core is an active material and the shell comprises material which is not active.

   33. The method as claimed in claim 31 wherein the core is not an active material and the shell comprises active material.

   34. The method as claimed in claim 3 1 wherein both the core and shell comprise active material.

   35. The method as claimed in claim 3 I wherein the core comprises molecular sieve.

   36. The method as claimed in claim 3 1 wherein the shell comprises molecular sieve.

   37. The method as claimed in claim 3 I wherein the shell comprises one or more metal oxides.

   38. The method as claimed in claim 31 wherein the shell comprises one or more mixed metal oxides.

   39. The method as claimed in claim 37 or 38 wherein the metal oxides or mixed metal oxides comprise one or more of the oxides of Fe, Ca, Mn and La.

   40. The method as claimed in claim 38 or 39 wherein the mixed metal oxides comprise one or more mixed metal oxides of perovskite structure.

   41. The method as claimed in claim 35 or 36 wherein the molecular sieve is a zeolite.

   42. The method as claimed in claim 41 wherein the zeolite is one or more of ZSM-5, ZSM-23, ZSM-48, FAU zeolite, LTL zeolite, silicalite-land members of the MCM-22 family.

   43. The method as claimed in any one of claims 31 to 42 wherein the shell layer comprises colloidal particles.

   44 the method as claimed in claim 43 wherein the particles have an average particle size of 500 nm or less.

   45. The method as claimed in any one of claims 31 to 44 wherein the treatment to induce the charge in surface charge is achieved by contact of the core particle or the shell particles with a solution comprising a cationic polymer.

   46. The method as claimed in claim 45 wherein excess cationic polymer is removed from the particles before bringing the particles into contact.

   47. The method as claimed in any one of claims 31 to 46 wherein the additional inorganic material is grown from the shell layer with chemical conversion of one or more materials of the shell layer.

   48. The method as claimed in claim 31 wherein the additional inorganic material is an inorganic matrix in contact with a plurality of core shell particles.

   49. The method as claimed in claim 48 wherein contact with the inorganic matrix material is effected by mixing and/or extrusion.

   50. The method as claimed in claim 48 or 49 wherein the inorganic matrix comprises active inorganic material.

   51. The method as claimed in claim 48 or 49 wherein the inorganic matrix comprises precursors to active inorganic materials.

   52. The method as claimed in claim 51 wherein the precursors to active inorganic materials arc converted to active inorganic material.

   53. The method as claimed in claim 52 wherein the conversion is to one or more molecular sieve materials.

   54. The method as claimed in claim 53 wherein the conversion is effected under hydrothermal synthesis conditions.

   55. A catalyst comprising a composite inorganic structure as claimed in any one claims I to 30 or as prepared by the method of any one of claims 31 to54, and inorganic binder.

   56. A conversion process for converting hydrocarbons comprising contacting a hydrocarbon fcedstream under hydrocarbon conversion conditions with a composite inorganic structure according to any one of claims Ito 30 or as prepared by the method of any one of claims 31 to 54 or a catalyst according to claim 55 to effect conversion of the hydrocarbon feedstream.

   57. An adsorption or separation process which comprises contacting a feedstream containing one or more adsorbates under adsorption or separation conditions with a composite inorganic structure according to any one of claims Ito 30 or as prepared by the method of any one of -43 -claims 31 to 54 to effect adsorption or separation of one or more of the adsorbates from the fcedstream.

   58. The process as claimed in claim 57 wherein the composite inorganic structure comprises an additional inorganic material that is selective for separation of the adsorbate(s) from the feedstream and a core that has a higher sorption capacity for the adsorbate(s) than the additional inorganic material.