A method of modifying a zeolite catalyst to increase para-xylene
selectivity of the zeolite catalyst in toluene methylation reactions is
provided. The method includes forming a slurry of a ZSM-5-type zeolite
and an aqueous solution of a phosphorus compound. Water is removed from
the slurry to provide a non-steamed, phosphorus treated ZSM-5 zeolite
catalyst without deposition of phosphorus onto the catalyst by
organophosphorus vapor deposition. The resulting non-steamed, phosphorus
treated ZSM-5 zeolite catalyst has a pore volume of from 0.2 ml/g or less
and provides greater than 80% para-xylene selectivity of mixed xylenes
when used in toluene methylation.