JPH0324456B

PURPOSE:In methylating toluene with a methylating agent in a gaseous phase, to obtain p-xylene advantageously, by using a catalyst obtained by treating a catalyst containing a crystalline aluminosilicate zeolite modified with phosphoric ester, etc., with a silicic ester. CONSTITUTION:Toluene is methylated with a methylating agent, especially methanol and/or dimethyl ether preferably at 100-700 deg.C, especially 300-700 deg.C at 1-800hr weight hour space velocity (WHSV) preferably in the presence of hydrogen in a gaseous phase in the presence of a catalyst containing crystalline aluminosilicate zeolite (especially zeolite ZSM-5) modified with phosphorus and/or its oxide to give p-xylene useful as an intermediate for polyester, etc., in higher concentration and higher toluene conversion ratio than a well-known method. The content of phosphorus in the catalyst is preferably 0.1-30wt% calculated as phosphorus atom.