Abstract: A process for converting a heavy aromatics feed to lighter aromatic products, such as benzene and xylene, by reacting C.sub.9+ aromatic hydrocarbons and toluene or benzene under transalkylation reaction conditions, over a first catalyst composition including a zeolite having a constraint index ranging from 0.5 to 3 and a hydrogenation component and a second catalyst composition including an intermediate pore size zeolite having a constraint index ranging from 3 to 12 and a silica to alumina ratio of at least about 5, to produce a transalkylation reaction product containing benzene or toluene and xylene. The benzene or toluene from the reaction product can then be distilled to obtain a benzene or toluene product.

Abstract: This invention relates to a catalytic reaction of an aromatic stream wherein a guard bed for the removal of nitrogen compounds from the aromatic hydrocarbon stream comprising the nitrogen compounds is provided to contact the hydrocarbon stream with a selective adsorbent having an average pore size less than about 5.5 Angstroms to produce a treated feedstream essentially free of the nitrogen compound. The selective adsorbent is a molecular sieve selected from the group consisting of pore closed zeolite 4A, zeolite 4A, zeolite 5A, silicalite, F-silicalite, ZSM-5 and mixtures thereof. The invention provides significant cost advantages when the feedstream is subject to slugs or surges in levels of nitrogen compounds which can be detrimental to downstream acid catalysts as found in aromatic conversion reactions.

Abstract: A catalyst for transforming aromatic hydrocarbons, preferably for dismutation of toluene to produce benzene and xylenes and transalkylation of toluene and aromatic compounds containing at least 9 carbon atoms per molecule, preferably trimethylbenzenes, to produce xylenes, contains a mordenite in its acid form in a proportion of 40% to 90% by weight and a binder, which is preferably alumina, and which is generally present in a proportion of 10% to 60% by weight. The mordenite contains less than 0.1% by weight of sodium and has a SiO.sub.2 /Al.sub.2 O.sub.3 molar ratio of over 40-60.

Abstract: A catalyst composition, a process for producing the composition and a hydrocarbon conversion process for converting a C.sub.9 + aromatic compound to a C.sub.6 to C.sub.8 aromatic hydrocarbon such as a xylene are disclosed. The composition comprises an acid-treated zeolite having impregnated thereon a metal or metal oxide. The composition can be produced by incorporating the metal or metal oxide into the zeolite. The hydrocarbon conversion process comprises contacting a fluid which comprises a C.sub.9 + aromatic compound with the catalyst composition under a condition sufficient to effect the conversion of a C.sub.9 + aromatic compound to a C.sub.6 to C.sub.8 aromatic hydrocarbon.

Abstract: The invention concerns the use of a catalyst for the dismutation of alkylaromatic hydrocarbons, preferably for the dismutation of toluene to produce benzene and xylenes, and/or for the transalkylation of alkylaromatic hydrocarbons, preferably for the transalkylation of toluene and trimethylbenzenes to produce xylenes. The catalyst is a composite comprising at least one zeolite with structure type mazzite, at least partially in its acid form, at least one zeolite with structure type mordenite, at least partially in its acid form, at least one matrix and, optionally, at least one element selected from the group formed by groups IB and VIII of the periodic classification of the elements.

Abstract: There is provided a process for producing alkylaromatics, especially ethylbenzene and cumene, wherein a feedstock is first fed to a transalkylation zone and the entire effluent from the transalkylation zone is then cascaded directly into an alkylation zone along with an olefin alkylating agent, especially ethylene or propylene.

Abstract: The present invention addresses heat integration in an alkylation/transalkylation process involving alkylation of an aromatic substrate with a C.sub.2 -C.sub.4 alklating agent coupled with separation to recover a monoalkylated aromatic product and liquid phase transalkylation of a polyalkylated product. Aromatic feedstock and a C.sub.2 -C.sub.4 alkylating agent are supplied to an alkylation reaction zone which is operated to produce an alkylated product. The output from the alkylation reaction zone initially travels through an arrangement of heat exchangers. From there, the alkylation effluent passes into the first separation zone which is operated to produce a lower boiling fraction comprising the aromatic substrate, which may be recycled to the alkylation reaction zone, and a higher boiling fraction comprising a mixture of monoalkylated and polyalkylated aromatics.

Abstract: A process for the transalkylation of benzene, toluene and alkylaromatic hydrocarbons containing 9 and 10 carbon atoms and at least one methyl or ethyl group to form alkylaromatic hydrocarbons containing 8 carbon atoms has been developed. The benzene, toluene, and alkylaromatic hydrocarbon reactants are introduced to a fixed bed reaction and adsorption zone operating under conditions effective for transalkylation and containing a catalyst effective to transalkylate the alkylaromatic hydrocarbons and benzene, and an adsorbent effective to selectively adsorb C.sub.9 and C.sub.10 alkylaromatic hydrocarbon reactants relative to the C.sub.8 alkylaromatic hydrocarbon products. Hydrogen and a desorbent capable of desorbing the C.sub.9 and C.sub.10 alkylaromatic hydrocarbons from the adsorbent is introduced to a first portion of the reaction and adsorption zone and an effluent containing at least one C.sub.8 alkylaromatic hydrocarbon product is withdrawn from a second portion of the reaction and adsorption zone.

Abstract: A catalyst composition, a process for producing the composition and a hydrocarbon conversion process for converting a C.sub.9 + aromatic compound to a C.sub.6 to C.sub.8 aromatic hydrocarbon such as a xylene are disclosed. The composition comprises a zeolite having impregnated thereon an activity promoter selected from the group consisting of molybdenum, molybdenum oxides, lanthanum, lanthanum oxides, and combinations of two or more thereof. The composition can be produced by incorporating the activity promoter into the zeolite. The hydrocarbon conversion process comprises contacting a fluid which comprises a C.sub.9 + aromatic compound with the catalyst composition under a condition sufficient to effect the conversion of a C.sub.9 + aromatic compound to a C.sub.6 to C.sub.8 aromatic hydrocarbon.

Abstract: The benzene content of light reformate is reduced by selectively alkylating the toluene contained therein with olefins by contacting the light reformate with the olefins in a catalyst bed. The catalyst structure in the catalyst bed acts as both a catalyst for the alkylation reaction and as distillation structure thus immediately separating the reaction product from the reaction zone to prevent reverse reactions and increase the overall reaction rate. The alkylated toluene is then used to transalkylate benzene to reduce the amount of benzene in the gasoline.

Abstract: A catalyst composition and a process for converting a hydrocarbon stream such as, for example, a C.sub.9 + aromatic compound to C.sub.6 to C.sub.8 aromatic hydrocarbons such as xylenes are disclosed. The catalyst composition comprises an aluminosilicate, and a metal wherein the weight ratio of aluminum to silicon is in the range of from about 0.002:1 to about 0.6:1. The process comprises contacting a hydrocarbon stream with the catalyst composition under a condition sufficient to effect the conversion of a hydrocarbon to a C.sub.6 to C.sub.8 aromatic hydrocarbon.

Abstract: A catalyst composition, a process for producing the composition and a hydrocarbon conversion process for converting a C.sub.9 + aromatic compound to a C.sub.6 to C.sub.8 aromatic hydrocarbon such as a xylene are disclosed. The composition comprises a zeolite having incorporated therein a promoter comprising carbon and a metal or metal oxide. The composition can be produced by incorporating a metal compound into the zeolite followed by thermal treatment of the resulting zeolite with a hydrocarbon. The hydrocarbon conversion process comprises contacting a fluid which comprises a C.sub.9 + aromatic compound with the catalyst composition under a condition sufficient to effect the conversion of a C.sub.9 + aromatic compound to a C.sub.6 to C.sub.8 aromatic hydrocarbon.

Abstract: There is provided a zeolite catalyst, which is first selectivated with a siliceous material and then treated with an aqueous solution comprising alkaline earth metal ions under ion exchange conditions.

Abstract: Process for the production of ethylbenzene by alkylation over a silicalite alkylation catalyst with the subsequent transalkylation of diethylbenzene with the alkylation catalyst and conditions selected to retard xylene production and also heavies production. A feedstock containing benzene and ethylene is applied to a multi-stage alkylation reaction zone having a plurality of series-connected catalyst beds containing a pentasil molecular sieve alkylation catalyst which is silicalite of a predominantly monoclinic symmetry having a silica/alumina ratio of at least 275. The feedstock is supplied to the alkylation reaction zone to cause gas-phase ethylation of benzene at a flow rate to provide a space velocity of benzene over the catalyst to produce a xylene concentration in the product of about 600 ppm or less based upon the ethylbenzene content.

Abstract: An improved process for producing xylene from feedstock containing C.sub.9 alkyl aromatic hydrocarbons with the aid of a catalyst capable of disproportionation, rearrangement, and dealkylation, wherein said improvement comprises performing the reaction in the presence of an aromatic hydrocarbon having one or more ethyl groups in an amount of 5 to 50 wt %.

Abstract: A process for the production of alkylaromatic hydrocarbons that operates with a high water content in an alkylation zone and a low water content in a transalkylation zone is disclosed. An aromatic feed and an acyclic feed are first passed through the alkylation reaction zone that operates at a high water content. A stripping column receives the effluent of the alkylation reaction zone, removes water and unreacted aromatic feed and produces a bottom stream containing unreacted aromatic feed and alkylated aromatics. A recycle column receives the bottom stream and produces an overhead stream of unreacted aromatic feed having a low water content. The overhead stream and a stream of polyalkylated aromatics are contacted in the transalkylation zone.

Abstract: The present invention relates to new crystalline zeolite SSZ-42 prepared by processes for preparing crystalline molecular sieves, particularly large pore zeolites, using an organic templating agent selected from the group consisting of N-benzyl-1,4-diazabicyclo?2.2.2!octane cations and N-benzyl-1-azabicyclo?2.2.2!octane cations.

Abstract: A catalyst composition and a process for converting a C.sub.9 + aromatic compound to C.sub.6 to C.sub.8 aromatic hydrocarbons such as xylenes are disclosed. The catalyst composition comprises a zeolite and a metal. The process comprises contacting a fluid stream containing a C.sub.9 + aromatic compound with the catalyst composition under a condition sufficient to effect the production of C.sub.6 to C.sub.8 aromatic hydrocarbon. Also disclosed is a process for producing the catalyst composition which can comprise: (1) impregnating a zeolite with an effective and coke-reducing amount of a metal compound under a condition sufficient to effect the production of a metal-promoted zeolite and (2) calcining the metal-promoted zeolite.

Abstract: A catalytic composition is described for the alkylation or transalkylation of aromatic compounds consisting of zeolite Beta, as such or modified by the isomorphic substitution of aluminium with boron, iron or gallium or by the introduction of alkaline/earth-alkaline metals following ion exchange processes, and of an inorganic ligand, wherein the extrazeolite porosity, i.e. the porosity obtained by adding the mesoporosity and macroporosity fractions present in the catalytic composition itself, is such as to be composed for a fraction of at least 25% of pores with a radius higher than 100 .ANG..

Abstract: A catalyst composition and a process for converting a hydrocarbon stream such as, for example, a C.sub.9 +aromatic compound to C.sub.6 to C.sub.8 aromatic hydrocarbons such as xylenes are disclosed. The catalyst composition comprises an aluminosilicate, and a metal wherein the weight ratio of aluminum to silicon is in the range of from about 0.002:1 to about 0.6:1. The process comprises contacting a hydrocarbon stream with the catalyst composition under a condition sufficient to effect the conversion of a hydrocarbon to a C.sub.6 to C.sub.8 aromatic hydrocarbon.

Abstract: The invention concerns the dismutation of alkylaromatic hydrocarbons, preferably the dismutation of toluene to produce benzene and xylenes, and/or the transalkylation of alkylaromatic hydrocarbons, preferably the transalkylation of toluene and trimethylbenzenes to produce xylenes, in a reaction zone comprising at least two catalytic beds each comprising a different catalyst, one of the catalysts containing at least one zeolite with mordenite type structure, at least partially in its acid form, and the other catalyst containing at least one zeolite with mazzite type structure, at least partially in its acid form, each catalyst containing at least one matrix and, optionally, at least one element selected from the group formed by groups IB and VIII of the periodic classification of the elements.

Abstract: A catalyst composition, a process for producing the composition and a process for transalkylation of C.sub.9 + aromatic compounds to C.sub.6 to C.sub.8 aromatic hydrocarbons are disclosed. The composition comprises a zeolite and tungsten wherein tungsten is preferably present as tungsten carbide which is impregnated on the zeolite. A preferred process for producing the catalyst composition which comprises: (1) contacting a zeolite with an effective amount of an acid under a condition sufficient to produce an acid-leached zeolite; and (2) impregnating acid-leached zeolite with an effective amount of tungsten-containing compound under a condition sufficient to effect the production of a tungsten carbide-promoted zeolite. The transalkylation process comprises contacting, in the presence of the catalyst composition, a fluid which comprises a C.sub.9 + aromatic compound with a hydrogen-containing fluid under a condition sufficient to effect the conversion of a C.sub.9 + aromatic compound to a C.sub.6 to C.sub.

Abstract: The invention concerns the use of a catalyst comprising at least one zeolite having a mazzite type structure in its acid form, the catalytic properties of the catalyst having been modified by depositing, on the external surface of the crystals, at least one metal selected from metals from group IIa of the periodic classification of the elements, such as Be, Mg, Ca, Sr or Ba, group IVb, such as Ti, Zr or Hf, group IIb such as Zn, Cd or Hg and group IVa such as Ge, Sn or Pb, said catalyst also comprising at least one matrix and, optionally at least one element selected from the group formed by IB and VIII of the periodic classification of the elements, for the dismutation of alkylaromatic hydrocarbons, preferably for the dismutation of toluene to produce benzene and xylenes, and/or for the transalkylation of alkylaromatic hydrocarbons, preferably for the transalkylation of toluene and trimethylbenzenes to produce xylenes.

Abstract: A process for shape-selective hydrocarbon conversion that involves initially contacting a feed stream which includes an alkylaromatic compound and a co-feed of water, under conversion conditions with a catalytic molecular sieve. Preferably, the catalytic molecular sieve has been modified by being ex situ selectivated with a silicon compound. After an effective amount of time, the water co-feed is omitted from the feed stream and the hydrocarbon conversion process is continued. Optionally, the catalytic molecular sieve can also be in situ trim-selectivated.

Abstract: A heavy aromatics feed is converted to lighter aromatics products, such as benzene, toluene and xylenes by contacting a C.sub.9 + aromatics fraction and benzene and/or toluene over a catalyst comprising a zeolite, such as ZSM-12, and a hydrogenation component, preferably platinum. The catalyst, complete with hydrogenation component, is treated to reduce aromatics loss. Treatment includes exposure to steam and/or sulfur after incorporation of the hydrogenation component. For additional stability and aromatics retention the steamed and/or sulfur treated catalyst is sulfided by cofeeding a source of sulfur. In a further embodiment of the invention a low hydrogen partial pressure is employed to retain aromatics.

Abstract: The present invention relates to a zeolite beta catalyst characterized by critical limits of weak and strong acid species and exceptionally high catalytic activity. The catalyst is activated at a temperature effective to substantially reduce the concentration of strong acid species, i.e., hydronium cations, without substantially reducing the concentration of weak acid species, i.e., hydroxoaluminum cations, preferably following a calcining step wherein a synthesized zeolite beta catalyst containing a templating agent is calcined at a temperature in the range of from about 200.degree. to 1000.degree. C. in order to remove a substantial portion of the catalyst templating agent and an ion-exchanging step wherein the calcined catalyst is ion-exchanged with a salt solution containing at least one hydrogen forming cation selected from NH.sub.4.sup.+ and quaternary ammonium.

Abstract: A process for producing alkylnaphthalene from a feedstock comprising isomers of dialkylnaphthalene and naphthalene by contacting the feedstock with a catalyst composition, in which the process comprising transalkylation between isomers of dialkylnaphthalene and naphthalene to produce monoalkylnaphthalene, and isomerization of dialkylnaphthalene, wherein the catalyst composition comprising a synthetic zeolite characterized by an X-ray diffraction pattern including interplanar d-spacing as set forth in Table A of the specification.

Abstract: There is disclosed a new form of zeolite beta which shows substantially greater stability and greater catalyst lifetime when used in the alkylation and transalkylation of aromatic compounds. The new, surface-modified zeolite beta is characterized by having surface aluminum 2p binding energies as measured by X-ray photoelectron spectroscopy, of at least 74.8 electron volts. This surface-modified zeolite beta is prepared by treating a templated zeolite beta with an acid at a pH between about 0 and about 2 and a temperature up to about 125.degree. C. for a time sufficient to modify the chemical environment of the surface aluminum atom without bringing about dealumination of the zeolite beta.

Abstract: A process for hydrodealkylating C.sub.9 -C.sub.12 alkyl-substituted benzenes (preferably trimethylbenzenes) to C.sub.6 -C.sub.8 aromatic hydrocarbons (in particular, toluene and xylenes) and C.sub.1 -C.sub.5 alkanes employs a catalyst containing zeolite Beta, nickel, molybdenum and sulfur (preferably as sulfides of nickel and of molybdenum).

Abstract: The present invention relates to new crystalline zeolite SSZ-44 prepared by processes for preparing crystalline molecular sieves, particularly large pore zeolites, using a N,N-diethyl-cis-2,6-dimethyl piperidinium cation templating agent.

Abstract: There is provided a process for shape selective toluene disproportionation that involves contacting a feedstream which includes toluene under conversion conditions, with ZSM-5 that has been selectivated at least once with an organosilicon selectivating agent. The conversion conditions of the hydrocarbon conversion process provide a toluene conversion of at least 40 wt. %.

Abstract: The present invention relates to new crystalline zeolite SSZ-41 which comprises oxides of (1) silicon or a mixture of silicon and germanium, and (2) zinc, said zinc being present in an amount from about 2 wt % to about 5 wt % of zinc metal based on the total weight of metals in said zeolite. Zeolite SSZ-41 may also optionally contain oxides of aluminum, iron, gallium or mixtures thereof. Zeolite SSZ-41 has the X-ray diffraction lines of Table I and has an argon adsorption capacity of at least about 0.06 cc/gm at 87.degree. K. Also disclosed are methods of making and using zeolite SSZ-41.

Abstract: This invention provides a process for the selective production of cumene comprising reacting benzene with propylene in the presence of a type-Y zeolite modified by treatment with a phosphorous compound. This invention also provides a process for the transalkylation of a polyalkylated benzene which comprises reacting the polyalkylated benzene in the presence of benzene and a type-Y zeolite modified by treatment with a phosphorous compound.

Abstract: An ex situ selectivated catalytic molecular sieve for enhanced shape selective hydrocarbon conversions in which a catalytic molecular sieve is modified by being exposed to at least two selectivation sequences, each sequence including an impregnation of the molecular sieve with a selectivating agent and a subsequent calcination of the impregnated molecular sieve. The ex situ selectivation method is also described, including the use of low volatility organic carriers for the selectivating agent. Also, a method for moderate steaming of the ex situ selectivated molecular sieve. Also a method for in situ trim-selectivating the ex situ selectivated catalytic molecular sieve. Also described is the process for shape selective hydrocarbon conversion comprising contacting a hydrocarbon feedstream under conversion conditions with the modified catalytic molecular sieve.

Abstract: There is provided a continuous toluene disproportionation process to selectively produce para-xylene. The process includes a steady-state of operation, wherein the conversion of toluene and selectivity to para-xylene is maintained at essentially constant target levels. Prior to such a steady-state of operation, the reaction is conducted under a relatively high temperature.

Abstract: There is provided a zeolite catalyst, which is first selectivated with a siliceous material and then treated with an aqueous solution comprising alkali metal ions under ion exchange conditions.

Abstract: Disclosed is a modified zeolite catalyst for the liquid phase alkylation and transalkylation of benzene comprising 30 to 70% by weight of H-beta zeolite with a silicon to aluminium ratio of 20 to 40; 0.5 to 10% by weight of halogen; and .gamma.-Al.sub.2 O.sub.3 of the balance. Also disclosed a method for preparing the said catalyst comprising adding a halogen-containing compound to a mixture of H-beta zeolite and a precursor of .gamma.-Al.sub.2 O.sub.3, forming followed by calcining.

Abstract: A process for shape selective hydrocarbon aromatization that involves contacting a hydrocarbon feedstream, under aromatization conditions, with a catalytic molecular sieve which has been modified by being ex situ selectivated with a silicon compound. The ex situ selectivation involves exposing the catalytic molecular sieve to at least two selectivation sequences, each sequence comprising contacting the catalytic molecular sieve with a silicon compound followed by calcination. Optionally, the modified catalytic molecular sieve may be further selectivated in situ.

Abstract: A process is provided for catalytic conversion of feedstock comprising aromatic compounds to product comprising aromatic compounds which differs from said feedstock. The catalyst required in the process comprises a crystalline material having the structure of MCM-58. Said crystalline material may have been treated with one or more monomeric or polymeric siloxane compounds which decompose to oxide or non-oxide ceramic or solid-state carbon species.

Abstract: This invention relates the use of a catalyst composition having the structure of ZSM-5 and a matrix material, which has been manufactured by a new and useful method, for organic compound, e.g., hydrocarbon compound, conversion. The organic compound conversion processes described include catalytic cracking, gasoline hydrofinishing, toluene disproportionation, xylene isomerization, and ethylbenzene production.

Abstract: This invention relates to use of synthetic porous crystalline MCM-58 as a catalyst component in catalytic conversion of organic compounds.

Abstract: This invention relates to a novel zeolite which has the crystal structure of zeolite beta. The novel zeolite SN-beta has a unique infrared absorbance spectrum, shows enhanced activity for transalkylation of di-isopropyl-benzene and shows less deactivation for cumene synthesis. The zeolite beta is prepared by taking an as-synthesized zeolite beta, steam treating it and then ammonium ion treating it to give a zeolite SN-beta with enhanced catalytic properties.

Abstract: There is provided a method for selectivating a zeolite, such as ZSM-5 which may result in functionalization of the zeolite with at least one organosiliceous group of the formula, SiR.sub.n (OX).sub.4-n, where R is at least one hydrocarbyl group, n is 1 or 2 and X is Si or H. This selectivation method involves vapor phase treatment of a zeolite with an organosilicon compound having at least 2 silicon atoms. This organosilicon compound may be a silicone compound, such as hexamethyldisiloxane, or a silane compound such as hexamethyldisilane. This contacting may take place in the presence of hydrogen and an organic carrier. The functionalized zeolites may provide a catalyst which is both highly active and highly selective for converting aromatic hydrocarbons, especially alkylbenzene compounds, to products comprising the para-isomer of dialkylbenzenes. The disproportionation of toluene is an example of such a reaction.

Abstract: A mixture of aromatic hydrocarbons, comprising ethylbenzene and at least one xylene, is isomerized using a two component catalyst system to convert the ethylbenzene to compounds that may be removed from the aromatic hydrocarbon stream and to produce a product stream wherein the para-xylene concentration is approximately equal to the equilibrium ratio of the para-isomer. The first catalyst comprises an intermediate pore size zeolite that is effective for ethylbenzene conversion. The first catalyst is preferably silica-bound. The second catalyst comprises an intermediate pore size zeolite, which further has a small crystal size and which is effective to catalyze xylene isomerization. Each of the catalysts of this invention may contain one or more hydrogenation/dehydrogenation component.

Abstract: A process and catalyst for Shape Selective Hydrocarbon Conversions such as the regioselective disproportionation of toluene to para-xylene wherein hydrocarbon to be converted is passed over a catalytic molecular sieve which is trim selectivated with a reaction stream comprising toluene and a silicon-containing high efficiency p-xylene selectivating agent under toluene conversion conditions. The toluene disproportionation process attains a single-pass para-xylene product over 95% coupled with a toluene conversion of at least 15%. The present invention also includes the highly para-selective catalyst which results from the treatment of a catalytic molecular sieve with a high efficiency p-xylene selectivating agent under the recited conditions.

Abstract: A process is provided for selective catalytic conversion of certain hydrocarbon feedstocks to product rich in para-dialkyl substituted benzenes. The catalyst required in the process comprises a crystalline material having the structure of PSH-3, MCM-22 or MCM-49, or a mixture of said crystalline materials, said crystalline material having been treated with one or more monomeric or polymeric siloxane compounds which decompose to oxide or non-oxide ceramic or solid-state carbon species.

Abstract: A process is provided for the disproportionation of a toluene feedstock over a metal promoted mordenite catalyst. The catalyst may contain between 1.0-1.5 weight percent nickel. The toluene feedstock is supplied to the reaction zone and into contact with the catalyst. The reaction zone is operated under disproportionation conditions. During disproportionation, heavy aromatic reformates, in concentration of at least 4 weight percent, are introduced into the reaction zone. Disproportionation product containing benzene and xylene is continuously withdrawn. The addition of the heavy aromatic reformate does not adversely affect toluene conversion rates, product selectivity to benzene, catalyst activity or catalyst life. Moreover, production of xylenes increase at the expense of production of heavies.

Abstract: There is provided a catalyst comprising a heteropoly acid, such as phosphotungstic acid, supported on a mesoporous crystalline material, such as M41S. A particular form of this M41S support is designated as MCM-41. There is also provided a method for preparing this catalyst by impregnating the heteropoly acid on the support. There is also provided a process for using this catalyst to catalyze acid catalyzed reactions, such as the isomerization of paraffins and the alkylation of aromatics.

Abstract: A method for the selective disproportionation of a substituted aromatic compound wherein the aromatic compound is passed over a catalytic molecular sieve which has been pre-selectivated with a silicon deposit and then subsequently treated with a silicon-containing, high efficiency p-xylene selectivating agent at conversion conditions. The present invention attains para-xylene product over 95% at a toluene conversion of at least 20%. The present invention also includes the highly para-selective catalyst which results from the pre-selectivation and subsequent treatment of a catalytic molecular sieve with a high efficiency p-xylene selectivating agent under the recited conditions.

Abstract: A zeolite, designated NU-85, is an intergrowth of zeolites EU-1 and NU-87. The zeolite is a useful catalyst in a wide variety of hydrocarbon conversion reactions including isomerisation and alkylation.