Conversion of aromatic hydrocarbons over MCM-22 and MCM-36 catalysts

Swelling the layered MCM-22 precursors with large organic molecules and then pillaring the resulting material with polymeric silica MCM-36 materials have been prepared. The BET surface area of MCM-36 was 2 times higher than that of MCM-22. The catalytic activity and selectivity of both MCM-36 and MCM-22 were investigated in the gas-phase alkylation of toluene with methanol at reaction temperatures ranging from 498 to 673K. The methylation of toluene produces a mixture of xylenes as main products. The influence of reaction temperature, pulse number, and toluene/methanol ratio upon the conversion of toluene and selectivities of the products were investigated. The superior catalytic performance of MCM-36 compared with MCM-22 for this reaction indicates that the open mesoporous structure can be successfully utilized to make acid sites of the layers accessible to large molecules.