Abstract: An industrially excellent method for selectively dealkylating a 1,4-dialkylbenzene in a dialkylbenzene mixture by the use of a specified zeolite catalyst is disclosed, which catalyst is a crystalline zeolite ion-exchanged with sodium ion, potassium ion, potassium ion, rubidium ion, or cesium ion. The specific zeolite catalyst is easy to prepare and allows selective dealkylation of the 1,4-dialkylbenzene and recovery of the formed olefins in a high yield and a high purity.

Abstract: Alkyl aromatic hydrocarbons wherein the alkyl group is a C.sub.1 to C.sub.10 alkyl group are transalkylated or dealkylated in the presence as catalyst of either a cation-exchangeable layered clay or a cation-exchangeable stabilized pillared layered clay.

Abstract: There is provided a mixed catalyst of ZSM-5 and ZSM-12. Alkylbenzenes, especially heavy aromatic bottoms from cumene production, may be cracked over this mixed catalyst.

Abstract: A process is disclosed for dealkylating durene under elevated temperatures and pressures with a polynuclear aromatic compound. The dealkylation is carried out in the presence of a carbon-containing molecular sieve.

Abstract: There is provided a mixed catalyst of ZSM-5 and ZSM-12. Alkylbenzenes, especially heavy aromatic bottoms from cumene production, may be cracked over this mixed catalyst.

Abstract: A process for dealkylating alkylaromatic hydrocarbons using intermediate pore size zeolites substantially free of acidity is disclosed.

Abstract: There is disclosed a system for measuring and controlling the concentration of hydrogen in hydrogen recycle processes used in oil refineries and petrochemical plants. The system is intended to reduce the amount of hydrogen and hydrocarbon vapor circulating in such systems, thus reducing the quantity of utilities needed to operate such systems. Specifically, there is a savings of compressor power and fuel required for heating. The system is dependent on the recognition that a decrease in cooling medium temperature results in an increase in hydrogen flow, which can be decreased to the minimum permissible without endangering catalyst activity and stability and product yield if hydrogen concentration is monitored, and that partial pressure is the key parameter.

Abstract: Titanium-containing molecular sieves are disclosed having use as molecular sieves and as catalyst compositions in hydrocarbon conversion and other processes. The instant invention employs novel titanium-containing molecular sieves comprising titanium, aluminum, phosphorus and oxygen and are generally employable in hydrocarbon conversion processes, including cracking, hydrocracking and hydrotreating.

Abstract: A method for selective dealkylation of 1,4-dialkylbenzene comprising selectively dealkylating a 1,4-dialkylbenzene in a dialkylbenzene mixture using as a catalyst crystalline zeolite having a silica/alumina ratio of at least 12 and a constrained index of 1 to 12 which is modified with an oxide of a metal or mettaloid, said crystalline zeolite being one ion-exchanged with a lithium ion.

Abstract: Molybdenum is ion exchanged into a crystalline aluminosilicate zeolite, replacing metals such as sodium, calcium, and potassium, by contacting the zeolite with an aqueous solution containing molybdenyl cations (i.e., MoO.sub.2.sup.2+) and having a pH below 7.0 but higher than that which would substantially affect the crystallinity of the zeolite. The resulting zeolite, when calcined or sulfided, is useful as a catalyst for hydrocarbon conversion reactions, particularly with respect to the hydrodealkylation of toluene to benzene and methane.

Abstract: Hydrocarbon conversion processes which use catalyst compositions comprising a core of silica with an overlying modified-silica zeolite, preferably containing aluminium, gallium or boron, show improved catalytic activity. The composites are prepared by introducing preformed silica particles, preferably with a crystallite size greater than 0.1.mu., into a reaction mixture comprising a silicon source, a source of the modifying element, and preferably an organic template such as a tetraalkylammonium compound to form the modified-silica zeolite with a constraint index of from 1 to 12. The weight ratio of the silica core to SiO.sub.2 in the reaction mixture is preferably 1:1 to 10:1.

Abstract: Improved aromatic conversion processes are provided by novel regeneration techniques. Aromatic processes that would benefit from this invention include those processes using catalysts comprising zeolites having a silica to alumina mole ratio of at least about 12 and a constraint index within the approximate range of 1 to 12 and which require regeneration to burn off coke from said catalysts. The improvement of the instant invention resides in conducting said regeneration in the presence of steam under controlled conditions to enhance the activity of the catalysts.

Abstract: There is disclosed a method for producing benzene and other useful compounds in high yields and selectivity which comprises hydro-dealkylating alkyl aromatic hydrocarbons in the presence of hydrogen using a catalyst mainly composed of a zeolite 15 to 20 equivalent % of exchangeable cations of which are exchanged with hydrogen ions. The reaction temperature is preferably 500.degree. to 650.degree. C.

Abstract: Incorporation of above about 50 ppm water into feed of a hydrocarbon conversion process using an AMS-1B crystalline borosilicate-based catalyst alters the product distribution produced in such process.

Abstract: A method for regenerating of rhodium-containing catalysts exhausted and sulphur-poisoned in the course of dealkylating alkyl benzenes or mixture thereof with steam or hydrogen, comprising the steps of burning out coke deposits by an oxygen-containing gas and chlorinating the catalyst with chlorine or with a chlororganic compound in a flow of hydrogen, an inert gas or a mixture of an inert gas with oxygen and moisture. The catalyst is additionally treated with ammonia or with a nitrogen-containing compound capable of decomposing under the treatment to yield ammonia in the presence of at least one component selected from the group consisting of: water, hydrogen, and nitrogen-oxygen mixture. The treatment can be conducted both in the liquid and the gaseous phases at temperatures ranging between 20.degree. and 650.degree. C. and at a pressure between 1 and 50 atm.The present invention can be used for regeneration of rhodium-containing catalysts and used for dealkylating alkyl benzenes with steam or hydrogen.

Abstract: Charge hydrocarbon stream containing diisopropyl toluene isomers is catalytically treated to recover product stream containing increased proportions of 1-methyl-3,5-diisopropyl benzene.

Abstract: Charge hydrocarbon stream containing diisopropyl toluene isomers is catalytically treated to recover product stream containing increased proportions of 1-methyl-3,5-diisopropyl benzene.

Abstract: Molybdenum is ion exchanged into a crystalline aluminosilicate zeolite, replacing metals such as sodium, calcium, and potassium, by contacting the zeolite with an aqueous solution containing molybdenyl cations (i.e., MoO.sub.2.sup.2+) and having a pH below 7.0 but higher than that which would substantially affect the crystallinity of the zeolite. The resulting zeolite, when calcined or sulfided, is useful as a catalyst for hydrocarbon conversion reactions, particularly with respect to the hydrodealkylation of toluene to benzene and methane.

Abstract: An improved process for selective cracking of 1,4-disubstituted aromatic compounds whereby the yield of recyclable olefin cracking product is increased. The process is carried out in the presence of a specified type of crystalline zeolite cracking catalyst (e.g. ZSM-5) and the reactor feed is admixed with ammonia or an organic amine.

Abstract: A process for hydrodealkylating alkyl-substituted aromatic hydrocarbons, e.g., toluene, by reaction with hydrogen in the absence of water vapor under relatively mild reaction conditions, and a catalyst therefor are disclosed. The process is effected at a temperature of from about 450.degree. to 650.degree. C., preferably from about 520.degree. to 620.degree. C., and pressures of from about 1 to about 30, preferably from about 5 to about 20 bar, and a liquid hourly space velocity of from about 1 to about 10, preferably from about 3 to about 8, in the presence of a catalyst which comprises a noble metal component comprising rhodium and a support comprising a metal aluminate having a spinel structure and corresponding to the empirical formula M Al.sub.2 O.sub.4.X Al.sub.2 O.sub.3, wherein X represents a value of from 0 to about 200 and M represents a metal selected from the group consisting of nickel, cobalt, copper, zinc, iron, and magnesium.

Abstract: Isomerization of xylenes in admixture with ethylbenzene by contact with a zeolite catalyst such as ZSM-5 is improved by use of zeolite which has been steamed at high temperature to reduce activity, the reaction being at a temperature above about 700.degree. F. At these conditions, conversion of ethylbenzene follows a different reaction path which permits high conversion of ethylbenzene to benzene without loss of xylenes of disproportionation.

Abstract: A process for the production of the internal isomers (3-phenyl, 4-phenyl and higher) from linear phenylalkane mixtures via selective cracking of the 2-phenylalkane isomer over crystalline zeolite catalysts having a silica to alumina ratio of at least about 12 and a constraint index, as herein defined, of about 1 to 12.

Abstract: Isomerization of xylenes in admixture with ethyl benzene by contact with a zeolite catalyst such as ZSM-5 is improved by use of zeolite having a substantial alkali metal content at a temperature above about 800.degree. F. At these conditions, conversion of ethylbenzene follows a different reaction path which permits high conversion of ethylbenzene to benzene without loss of xylenes by disproportionation.

Abstract: This invention relates to a method for preparing an acid catalyst which comprises contacting a copolymer of perflurovinyl ether and tetrafluoroethylene containing pendant sulfonate groups with a strong acid having a pKa of less than 1 to convert said sulfonate groups into sulfonic acid groups, removing the excess strong acid and salt formed from such conversion, preferably by washing said sulfonic acid group containing polymer with a solvent in which said salt and said acid are soluble, and removing said solvent from said sulfonic acid group containing polymer. Preferably the strong acid is nitric acid, e.g., aqueous nitric acid, and said solvent is aqueous. The excess solvent may be removed by drying at a temperature of from 50 to 200 degrees C., preferably at reduced pressures. The use of the catalyst prepared by this method for isomerization of hydrocarbons, e.g., xylene, and dealkylation of alkylbenzenes, e.g., diethylbenzene and diisopropylbenzene are also claimed.

Abstract: Isomeric mixtures of non-polar disubstituted aromatic compounds are brought into contact with a shape selective crystalline zeolite catalyst, under cracking or transalkylation conditions, to undergo selective reaction of the 1,4-isomer, thereby leaving the 1,2-isomer and/or 1,3-isomer in excess of equilibrium. The shape selective zeolite catalyst employed herein comprises a crystalline zeolite having a silica to alumina ratio of at least 12 and a constraint index, as herein defined, within the approximate range of 1 to 12.

Abstract: A process for purifying aromatic hydrocarbons contained in liquid products of refining petroleum fractions or liquid products of coal coking or low-temperature carbonization from non-aromatic hydrocarbons which comprises heat-treatment of said liquid products at a temperature ranging from 750.degree. to 950.degree. C. under a pressure within the range of from 1 to 10 atm in the presence of acyclic C.sub.2 -C.sub.4 hydrocarbons employed separately or in various combinations at a weight ratio between said acyclic hydrocarbons and said liquid products being of at least 0.3. The heat-treatment results in a vapor-gas mixture which is cooled to isolate a condensate containing predominantly aromatic hydrocarbons. The process is technologically simple and makes it possible to purify aromatic hydrocarbons practically without decomposition thereof.

Abstract: Isomerization of xylenes in admixture with ethyl benzene by contact with a zeolite catalyst such as ZSM-5 is improved by use of zeolite having a silica/alumina ratio of at least 500 at a temperature above about 800.degree. F. At these conditions, conversion of ethyl benzene follows a different reaction path which permits high conversion of ethyl benzene to benzene without loss of xylenes by disproportionation.

Abstract: Mixtures of C.sub.8 aromatic hydrocarbons are contacted in vapor phase with acid zeolite ZSM-5. The xylene content is thereby isomerized and the ethyl benzene content of the charge is converted in a manner which results in net increase of aromatic rings.