Selective production of para dialkyl benzene

Claim 1

Process for selectively producing the para isomer of the compound: ##STR4## where n is 1 or 2 which comprises contacting a hydrocarbon precursor selected from the group consisting of ethylbenzene and mixtures of ethylbenzene or toluene with ethylene in which the molar ratio of ethylbenzene or toluene to ethylene is between about 1 and about 10, under conversion conditions, in the presence of a catalyst comprising a crystalline aluminosilicate zeolite, characterized by a silica to alumina mole ratio of at least about 12, a constraint index within the approximate range of 1 to 12 and a minimum crystal dimension greater than about 0.5 micron, said zeolite having undergone the following prior sequential treatment: (1) steaming at a temperature of between about 250° and about 1000° C. for a period of at least 0.5 hour; (2) impregnation with at least about 0.25 weight percent of phosphorus oxide; (3) impregnation with at least about 0.25 weight percent of magnesium oxide and (4) coking for deposition of at least about 1 weight percent of coke thereon to yield a resulting reaction product mixture in which the para isomer of said compound is present in an amount exceeding 99 percent of the total of said compound produced.