Abstract: A catalytic process is provided for the selective production of para-xylene by contacting, under conversion conditions, an olefinic charge stock with a catalyst comprising a crystalline aluminosilicate zeolite having a silica to alumina ratio of at least about 12, a constraint index, as hereinafter defined, within the approximate range of 1 to 12 and which has combined therewith magnesium in an amount of at least about 0.5 percent by weight.

Abstract: Process for the selective production of para-substituted benzene derivatives characterized by the formula: ##STR1## where R.sub.1 and R.sub.2 are individually methyl or ethyl by alkylation of a mono alkyl benzene wherein the alkyl substituent contains 1 or 2 carbon atoms, i.e. toluene or ethylbenzene, with a methylating or ethylating agent in the presence of a catalyst comprising the crystalline aluminosilicate zeolite ZSM-23. The products selectively produced are para-xylene, para-ethyltoluene or para-diethylbenzene.

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 treatment with steam to reduce the alpha value thereof to less than about 500 and preferably within the range of less than about 20 but greater than zero.

Abstract: Process for the alkylation of aromatic hydrocarbons by contacting same with an olefin alkylating agent in a reaction zone maintained under conditions such that said alkylation is accomplished in the vapor phase and 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, of from 1 to 12, said catalyst having been modified by the addition thereto of phosphorus in an amount of at least about 0.5 percent by weight.

Abstract: V-P-Zr catalysts having high activity and selectivity and good physical strength for the oxidation of alkanes, cycloalkanes and mixtures rich in them to dicarboxylic acid anhydrides (e.g. maleic anhydride) are prepared by reacting an aqueous mixture of vanadium pentoxide and a hydroxy-or oxo- alkanoic acid or formaldehyde, a zirconium salt, and phosphoric acid.

Abstract: V-P-Zr catalysts having good activity and selectivity and high physical strength for the oxidation of alkanes, cycloalkanes and mixtures rich in them to dicarboxylic acid anhydrides (e.g. maleic anhydride) are prepared by refluxing an aqueous mixture of vanadium pentoxide and lower dialkyl phosphonate, adding a zirconium salt, and then adding phosphoric acid.