Zeolite catalyzed alkylation of toluene by alcohol

Vapor-phase methylation of toluene using methanol and its isopropylation with 2-propanol has been investigated ina down flow reactor under atmospheric conditions using N2 carrier over a series of surface modified andunmodified ZSM-5 (Si/Al= 60-170) loaded with H3PO4, differing in the external surface treatment of the zeolites.The feed molar ratios of toluene/methanol and toluene/2-propanol were varied over a wide range (8-0.125), andthe optimum feed ratio of toluene/alcohol was less than 0.5 in both cases. Space velocity employed in toluenemethylation reported as WHSV (toluene) = 1.2114, and the space velocity employed in toluene isopropylationreported as WHSV (toluene) = 0.8 III. The methylation reactions were carried out in the temperature range of 623-773 K, and the isopropylation reactions were carried out in the temperature range of 483-583 K. Atmosphericpressures was maintained in all runs. Catalysts containing 0-4.9 wt.% P were prepared using modified andunmodified ZSM-5 zeolites, and their catalytic performance for vapor-phase alkylation of toluene with methanoland 2-propanol were investigated. The optimum phosphorous content for methylation was 2.1 wt.% P which wasgreater than the optimum phosphorous loading for isopropylation (0.7 wt.% P)