Abstract
Vapor-phase catalytic reaction of pseudocumene with methanol has been studied by flow method using silica-alumina catalyst modified with nineteen kinds of metal salt.
The silica-alumina catalyst containing 3.5wt% Ag showed the best result. The conversion of pseudocumene was 34% and the selectivity to durene and tetramethylbenzenes, 34% and 62%, respectively under the optimum reaction conditions: reaction temperature, 250°C; molar ratio of H2/(pseudocumene+methanol), 0.5-2.0; pseudocumene/methanol, 2.0; LHSV, 1.0hr-1.
Rate of reaction increased in the presence of hydrogen. The activity of the catalyst became constant after three-hours' run, and the catalyst could be regenerated by heating in the air at 600°C for three hours.
Disproportionation of trimethylbenzenes to xylenes and tetramethylbenzenes, and isomerization of xylenes, trimethylbenzenes, and tetramethylbenzenes occurred in addition to methylation of pseudocumene under these reaction conditions.
