Modified ZSM-5-SBA-15 and its alkylation performance for toluene with methanol

ZSM-5 was modified by metal M (M for Mg, Ni or Sr) using impregnation method first, then the micro-mesoporous composite molecular sieve of M-ZSM-5-SBA-15 was synthesized by post synthesis. The samples were characterized by means of XRD, N₂ adsorption-desorption, FT-IR, NH₃-TPD and Py-FTIR. The influence of silica alumina ratio of the HZSM-5 and different metals modification on alkylation performance were investigated. The results showed that the ZSM-5/SBA-15 composite molecular sieve with silica alumina ratio of 80 showed the best performance in alkylation. The introduction of Sr passivated strong Brnsted acid centers and reduced the ratio of Brnsted acid and Lewis acid of ZSM-5-SBA-15(80), resulting in good performance in alkylation with a toluene conversion of 30.15% and a p-xylene selectivity of 77.41%.