Abstract: Process for the selective production of para-xylene by methylation of toluene in the presence of a catalyst comprising a crystalline aluminosilicate zeolite, said zeolite having a silica to alumina ratio of at least about 12 and a constraint index, as hereinafter defined, within the approximate range of 1 to 12, which catalyst has undergone prior modification by the addition thereto of phosphorus oxide and magnesium oxide, each in an amount of at least about 0.25 percent by weight.

Abstract: Disproportionation of toluene with high conversion thereof to produce benzene and xylenes rich in the para isomer is accomplished by subjecting toluene to disproportionation conditions in the presence of a catalyst comprising a crystalline aluminosilicate zeolite, said zeolite having a silica to alumina ratio of at least about 12 and a constraint index, as hereinafter defined, within the approximate range of 1 to 12, which catalyst has undergone prior modification by treatment with an ammonium hydrogen phosphate to deposit at least about 0.5 weight percent of phosphorus thereon.

Abstract: Process for the selective production of para-xylene by methylation of toluene in the presence of a catalyst comprising a crystalline aluminosilicate zeolite, said zeolite having a silica to alumina ratio of at least about 12 and a constraint index, as hereinafter defined, within the approximate range of 1 to 12, which catalyst has undergone prior modification by treatment with an ammonium hydrogen phosphate to deposit at least about 0.5 weight percent of phosphorus thereon.

Abstract: Disproportionation of toluene to produce benzene and xylenes rich in the para isomer is accomplished by subjecting toluene to disproportionation conditions in the presence of a catalyst comprising a crystalline aluminosilicate zeolite, said zeolite having a silica to alumina ratio of at least about 12 and a constraint index, as hereinafter defined, within the approximate range of 1 to 12, said catalyst having been modified by initial treatment with an ammonium phosphate followed by treatment with a magnesium compound to yield a composite containing a minor proportion of an oxide of phosphorus and a minor proportion of an oxide of magnesium.

Abstract: Disproportionation of toluene to produce benzene and xylenes rich in the para isomer is accomplished by subjecting toluene to disproportionation conditions in the presence of a catalyst comprising a crystalline aluminosilicate zeolite, said zeolite having a silica to alumina ratio of at least about 12 and a constraint index, as hereinafter defined, within the approximate range of 1 to 12, said catalyst having been modified by initial treatment with an ammonium phosphate followed by treatment with a magnesium compound to yield a composite containing a minor proportion of an oxide of phosphorus and a minor proportion of an oxide of magnesium.

Abstract: Disproportionation of toluene to produce benzene and xylenes rich in the para isomer is accomplished by subjecting toluene to disproportionation conditions in the presence of a catalyst comprising a crystalline aluminosilicate zeolite, said zeolite having a silica to alumina ratio of at least about 12 and a constraint index, as hereinafter defined, within the approximate range of 1 to 12, said catalyst having been modified by the addition thereto of a minor proportion of an oxide of phosphorus and a minor proportion of an oxide of magnesium.

Abstract: Process for the selective production of para-xylene by methylation of toluene in the presence of a catalyst comprising a crystalline aluminosilicate zeolite, said zeolite having a silica to alumina ratio of at least 12 and a constraint index, as hereinafter defined, within the approximate range of from 1 to 12, which catalyst has undergone prior treatment to deposit a coating of between about 15 and about 75 weight percent of coke thereon.

Abstract: Catalyst of a crystalline aluminosilicate zeolite, said zeolite having a silica to alumina ratio of at least about 12 and a constraint index, as hereinafter defined, within the approximate range of 1 to 12, the surface of which catalyst has been modified by contact with a polymer made up of meta-carborane units connected by siloxane units and process for the selective production of para-xylene by methylation of toluene in the presence of said catalyst.