Abstract: An improved process is disclosed for the selective disproportionation of toluene. The process preferably uses a disproportionation catalyst comprising MFI bound with alumina phosphate. Running the process at a hydrogen to hydrocarbon ratio between 0.2 to 0.5 improves the yield of para-xylene. Optional periodic rejuvenation by increasing the hydrogen to hydrocarbon ratio removes some carbon deposits and restores catalyst activity.

Abstract: A simultaneous process for simulated moving-bed dismutation and separation of a toluene feedstock into benzene and xylenes in the presence of a hydrogen-rich desorbent in at least one adsorber-reactor (100) that contains beds of a solid and comprises at least three zones (23, 24, 25) is described. Vapor-phase or supercritical feedstock (1) is introduced at the inlet of a reaction and adsorption zone (25) (zone III), and a raffinate (15) that is high in benzene and desorbent is recovered at the outlet. Desorbent (5, 7) is introduced at the inlet of a desorption zone (23) (zone I), and an effluent from which is drawn off a portion (8) in the form of an extract that is high in xylenes and desorbent is recovered at the outlet. The other portion of the effluent of zone I is introduced at the inlet of a reaction and desorption zone (24) (zone II), and an effluent is recovered at the outlet that is sent back to the inlet of reaction and adsorption zone III.

Abstract: A method for producting a solid acid catalyst is provided which produces a shaped material of a solid acid catalyst containing a sulfureous component but have a high activity and having a practically sufficient handleability and mechanical strength involves the steps of (a) fabricating a support containing a portion of zirconia and/or hydrated zirconia and a portion of alumina and/or hydrated alumina and having a peak diameter in the range of 0.05 to 1 &mgr;m in a pore diameter distribution of 0.05 to 10 &mgr;m; and having a sulfuerous component supported on the support or (b) fabricating a support containing a portion of zirconia and/or hydrated zirconia and a portion of alumina and/or hydrated alumina and including pores having a pore diameter of not less than 0.05 &mgr;m and not more than 1 &mgr;m occupying a pore volume of 0.05 to 0.5 ml/g and pores having a pore diameter of about 1 &mgr;m and not more than 10 &mgr;m occupying a pore volume of below 0.

Abstract: A pressure swing adsorption process to separate para-xylene and ethylbenzene from a C8 aromatics stream produced by toluene conversion uses a para-selective adsorbent, preferably a non-acidic, medium pore molecular sieve of the MFI structure type, and is operated isothermally in the vapor phase at elevated temperatures and pressures. A fixed bed of adsorbent is saturated with pX and EB, which are preferentially adsorbed, then the feed to the process is stopped. Lowering the partial pressure desorbs the pX and EB giving a pX/EB-rich effluent. A stream of non-adsorbed mX and oX may be obtained before desorbing pX and EB.

Abstract: Process for the preparation of 2,6-dimethylnaphthalene comprising reacting with at least one aromatic hydrocarbon, in the presence of a zeolitic catalyst, a mixture of naphthalenes comprising a cut obtained by the fractionation of suitable petrochemical streams and subsequent treatment of the product thus obtained with a solid acid.

Abstract: This invention provides a process for conducting Stille coupling reactions. The processes of the present invention make use of N-heterocyclic carbenes as ancillary ligands in Stille couplings of aryl halides.

Abstract: Disclosed herein is a catalyst composition for transalkylation of alkylaromatic hydrocarbons which exhibits the percent conversion of ethyltoluene higher than 50 wt %, is composed of mordenite (100 pbw), inorganic oxide and/or clay (25-150 pbw), and at least one metal component of rhenium, platinum, and nickel, and contains mordenite such that the maximum diameter of secondary particles of mordenite is smaller than 10 &mgr;m. Disclosed also herein is a process for producing xylene by the aid of said catalyst from alkylaromatic hydrocarbons containing C9 alkylaromatic hydrocarbons containing more than 5 wt % ethyltoluene and less than 0.5 wt % naphthalene, in the presence of hydrogen.

Abstract: An improved process is disclosed for the selective disproportionation of toluene. The process uses a zeolitic catalyst which is oil-dropped in an amorphous aluminum phosphate binder and optionally is selectively precoked prior to toluene disproportionation. The catalyst and process provide enhanced selectivity for the production of paraxylene.

Abstract: An improved process is disclosed for the selective transalkylation of toluene and, optionally, of C9 aromatics. The process preferably uses a bound sulfated zirconia catalyst to provide improved selectivity for the production of xylenes.

Abstract: A process for toluene disproportionation which obtains high xylene yields while minimizing ethylbenzene production employs a dual catalyst bed. The first bed employs an acid zeolite, e.g., ZSM-5 which disproportionates toluene and the downstream second bed uses an acid zeolite having hydrogenation-dehydrogenation activity, e.g., PtZSM-5, to selectively eliminate ethylbenzene.

Abstract: A process for the preparation of at least one spherically shaped porous microcomposite is provided which microcomposite comprises a perfluorinated ion-exchange polymer containing pendant sulfonic and/or carboxylic acid groups entrapped within and highly dispersed throughout a network of inorganic oxide, wherein the weight percentage of the perfluorinated ion-exchange polymer in the microcomposite is from about 0.1 to about 90 percent, and wherein the size of the pores in the microcomposite is about 0.

Abstract: A simultaneous process for simulated moving-bed dismutation and separation of a toluene feedstock into benzene and xylenes in the presence of a hydrogen-rich desorbent in at least one adsorber-reactor (100) that contains beds of a solid and comprises at least three zones (23, 24, 25) is described. Vapor-phase or supercritical feedstock (1) is introduced at the inlet of a reaction and adsorption zone (25) (zone III), and a raffinate (15) that is high in benzene and desorbent is recovered at the outlet. Desorbent (5, 7) is introduced at the inlet of a desorption zone (23) (zone I), and an effluent from which is drawn off a portion (8) in the form of an extract that is high in xylenes and desorbent is recovered at the outlet. The other portion of the effluent of zone I is introduced at the inlet of a reaction and desorption zone (24) (zone II), and an effluent is recovered at the outlet that is sent back to the inlet of reaction and adsorption zone III.

Abstract: A process of preparing an alkylated benzene or mixture of alkylated benzenes involving contacting a benzene feedstock with a solid acid, such as an acidic clay or acid zeolite, in a pretreatment zone at a temperature greater than about 130° C. but less than about 300° C. to form a pretreated benzene feedstock, and thereafter contacting the pretreated benzene feedstock with (a) an alkylating agent in an alkylation zone or (b) a transalkylating agent in a transalkylation zone, in the presence of an alkylation/transalkylation catalyst so as to prepare the alkylated benzene or mixture of alkylated benzenes. The pretreatment step improves the lifetime of the alkylation/transalkylation catalyst. Preferred products are ethylbenzene and cumene.

Abstract: A process for the production of ethylbenzene by the alkylation of benzene over a molecular sieve aromatic alkylation catalyst followed by transalkylation of polyalkylated aromatic components and then liquid phase alkylation. A feedstock containing benzene and ethylene is supplied to a first alkylation reaction zone containing a molecular sieve aromatic alkylation catalyst. The reaction zone is operated at temperature and pressure conditions to cause gas phase ethylation of the benzene with the production of an alkylation product comprising a mixture of ethylbenzene and polyalkylated aromatic components including diethylbenzene with xylene present in only small amounts. The output from the alkylation reaction zone is supplied to an intermediate recovery zone for the separation and recovery of ethybenzene, a polyalkylated aromatic compound component including diethylbenzene.

Abstract: An improved process is disclosed for the selective disproportionation of toluene. The process uses a zeolitic catalyst which is selectively precoked prior to toluene disproportionation in a manner to avoid a large temperature rise across a bed of the catalyst during precoking. The catalyst and process provide enhanced selectivity for the production of paraxylene.

Abstract: A separation arrangement for a cumene process that operates with a relatively wet feed to an alkylation zone and relatively dry feed to a transalkylation zone reduces utilities and capital expenses for the separation and recycle of distinct wet and dry components by using an arrangement that first separates effluent from the trans alkylation and alkylation reaction zone in a benzene column before performing light ends and drying in a downstream depropanizer column. The arrangement uses a portion of the net overhead stream from the benzene column as a wet recycle stream for return to the alkylation reaction zone and sends another portion of the benzene net overhead to the depropanizer to supply a dry benzene recycle for the trans alkylation reaction zone.

Abstract: A process for reducing the amount of undesirable byproducts, for example multi-ring compounds known as heavy residue in a process for the alkylation of an aromatic hydrocarbon with an olefin using a silicalite catalyst is disclosed. The process comprises supplying a feedstock containing benzene to a reaction zone with an alkylating agent in a molar ratio of benzene to alkylating agent of from about 2:1 to about 20:1 and into contact with an aluminosilicate alkylation catalyst having an average crystallite size of less than about 0.50 .mu.m and wherein the size of about 90% of the crystallites is less than 0.70 .mu.m. The catalyst is characterized by an Si/Al atomic ratio in the range from between 50 and 150 and a maximum pore size in the range from about 1000 to 1800 .ANG.. The catalyst has a sodium content of less than about 50 ppm and the reaction is carried out under conversion conditions including a temperature of from about 250.degree. C. to about 550.degree. C.

Abstract: A catalyst composition and a process for hydrodealkylating C.sub.9 + aromatic compounds such as, for example, trimethylbenzenes, to C.sub.6 to C.sub.8 aromatic hydrocarbons such as toluene and xylenes are disclosed. The composition comprises an alumina and a silica wherein the weight ratio of aluminum to silicon is in the range of from about 0.005:1 to about 0.25:1. The 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.8 aromatic hydrocarbon; and the C.sub.9 + aromatic compound contains at least 9 carbon atoms.

Abstract: An improved process combination is disclosed for the selective disproportionation of toluene. The combination comprises selective hydrogenation of a toluene feedstock followed by disproportionation using a zeolitic catalyst which is oil-dropped in an aluminum phosphate binder to achieve a high yield of paraxylene. Optionally, the catalyst is selectively precoked prior to toluene disproportionation. The catalyst and process provide improved selectivity for the production of paraxylene.

Abstract: An improved catalyst and process are disclosed for the selective disproportionation of toluene. The process uses a zeolitic catalyst which is oil-dropped in an aluminum phosphate binder and has an X-ray diffraction pattern showing characteristic intensities at specified Bragg angles. Optionally, the catalyst is selectively precoked prior to toluene disproportionation. The catalyst and process provide improved selectivity for the production of paraxylene.

Abstract: A supported Lewis acid catalyst system for catalyzing hydrocarbon conversion reactions including cationic polymerization, alkylation, isomerization and cracking reactions is disclosed, wherein the catalyst system comprises an inorganic oxide support having immobilized thereon a least one strong Lewis acid comprising at least one metal salt of a strong Bronsted acid wherein the metal is selected from the group consisting of aluminum, boron gallium, antimony, tantalum, niobium, yttrium, cobalt, nickel, iron, tin, zinc, magnesium barium strontium, calcium, tungsten, molybdenum and the metals of the lanthanide series and wherein the strong Bronsted acid is selected from the group consisting of mineral and organic acids stronger than 100% sulfuric acid.

Abstract: Para-xylene is produced from a paraselective toluene disproportionation reactor, effluent (3) is distilled to eliminate toluene and benzene in at least 2 distillation columns (C1), (C2), and the xylenes (8) are crystallized at least once (10) at between +10.degree. C. and -30.degree. C. The separated mother liquor (14) is adsorbed on a zeolitic sieve in the presence of toluene in a simulated moving bed (15). This latter produces a raffinate (16) containing toluene which is depleted in para-xylene which is distilled in a distillation column (C4), and an extract which is enriched in para-xylene and contains toluene, which is recycled to columns (C1, C2). The para-xylene crystals are purified by washing with toluene and distillation or by partial melting (30) followed by washing with molten high purity para-xylene.

Abstract: There is provided a process for converting hydrocarbons which utilizes a zeolite bound zeolite catalyst that has enhanced performance when utilized in hydrocarbon conversion processes, e.g., catalytic cracking, alkylation, disproportionation of toluene, isomerization, and transalkylation reactions. The catalyst comprises a first zeolite having particles of greater than about 0.1 micron average particle size and a binder comprising second zeolite particles having an average particle size less than said first particles.

Abstract: Aromatic hydrocarbons are efficiently converted by bringing feedstock containing from 5 to 50% by weight of an aromatic hydrocarbon having an ethyl group and a C.sub.9 alkyl aromatic hydrocarbon into contact with a catalyst capable of disproportionation, trans-alkylation and dealkylation, a secondary particle diameter of a zeolite in the catalyst being 10 .mu.m or less.

Abstract: The residual olefin content of the alkylation reaction product of a single-ring aromatic hydrocarbon with an olefin is reduced by removing at least a portion of the non-alkylated single-ring aromatic hydrocarbon, then reacting the remaining alkylation reaction product at about atmospheric pressure and at a temperature of about from 100.degree. to 250.degree. C. in the presence of an acidic catalyst. The olefin has at least sixteen carbon atoms. The acidic catalyst can be a molecular sieve (such as a natural or synthetic zeolite) or clay.

Abstract: An improved process is disclosed for the selective disproportionation and transalkylation of toluene. The process uses a zeolitic catalyst, preferably comprising a binder, containing a weak metal in a defined reduced state which is believed to provide Lewis acidity in the catalyst. The catalyst and process provide improved selectivity for the production of paraxylene.

Abstract: A process for the transalkylation of benzene, toluene and alkylaromatic hydrocarbons containing nine and ten carbon atoms form alkylaromatic hydrocarbons containing eight carbon atoms has been developed. The fixed bed reaction and adsorption zone contains a transalkylation catalyst 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 are introduced to a first portion of the zone and an effluent containing at least one C.sub.8 alkylaromatic hydrocarbon product is withdrawn from a second portion of the zone. After a period of time, the desorbent is redirected to the second portion of the zone and concurrently the effluent containing at least one C.sub.8 alkylaromatic hydrocarbon product is withdrawn from the first portion of the zone.

Abstract: A process for producing at least one C.sub.8 alkylaromatic hydrocarbon product from a feedstock containing at least one C.sub.9 or C.sub.10 alkylaromatic hydrocarbon reactant using simulated moving bed reactive chromatography has been developed. At least a portion of the reactants are transalkylated to form at least one product in a zone of the simulated moving bed with concurrent separation of at least one alkylaromatic hydrocarbon using the adsorbent. The adsorbed alkylaromatic hydrocarbon is desorbed from the adsorbent in a subsequent zone of the simulated moving bed and the transalkylation of the reactants with concurrent separation of at least one alkylaromatic hydrocarbon using the adsorbent is continued.

Abstract: There is provided a catalyst comprising ZSM-5, rhenium which is impregnated onto the catalyst, and a selectivating agent. The selectivating agent may be coke and/or a siliceous material. The catalyst is particularly useful for catalyzing toluene disproportionation reactions. Methods for making this catalyst and processes for using this catalyst in toluene disproportionation are also provided.

Abstract: Ethylbenzene is produced from benzene and ethylene in an alkylation reactor wherein the feedstocks also contain propylbenzenes and/or components that produce propylbenzene. Polyethylbenzenes are also produced in the process. The ethylbenzene product and unreacted benzene are separated and then the propylbenzenes are separated from the polyethylbenzenes by distillation. The propylbenzenes are destroyed in a vapor-phase reactor and the polyethylbenzenes are transalkylated with benzene in a liquid or partial liquid phase at a lower temperature.

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: 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: Para-xylene is produced from a paraselective toluene disproportionation reactor, effluent is distilled to eliminate toluene and benzene in at least 2 distillation columns, and the xylenes are crystallized at least once at between +10.degree. C. and -30.degree. C. The separated mother liquor is adsorbed on a zeolitic sieve in the presence of toluene in a simulated moving bed. This latter produces a raffinate containing toluene which is depleted in para-xylene which is distilled in a distillation column, and an extract which is enriched in para-xylene and contains toluene, which is recycled. The para-xylene crystals are purified by washing with toluene and distillation or by partial melting followed by washing with molten high purity para-xylene.

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: Carburization and metal-dusting while hydrodealkylating a hydrodealkylatable hydrocarbon are reduced even in the substantial absence of sulfur.

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 transalkylation reactor having a plurality of catalyst beds with individual feed points for each bed for converting poly alkylated benzene, typically products from a alkylation process, to mono alkylated benzene. Only so many of the catalyst beds are used to optimize the conversion of poly substituted benzene to mono substituted benzene. As the catalyst ages more of the beds are utilized to maintain conversion.

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 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 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: 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: 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: 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: 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: 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 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: Relatively short chain alkyl aromatic compounds are prepared by alkylating or transalkylating an alkylatable aromatic compound with a relatively short chain alkylating or transalkylating agent under sufficient reaction conditions in the presence of catalyst comprising an acidic solid material which comprises a Group IVB metal oxide, such as zirconia, modified with an oxyanion of a Group VIB metal, such as tungsten.