Synthesized high-silica hierarchical porous ZSM-5 and optimization of its reaction conditions in benzene alkylation with methanol

摘要

In our present work, the high-silica hierarchical porous ZSM-5 with appropriate Br(o|¨)nsted acidity and hierarchical porous structure was synthesized by sol-gel method for continuously catalytic conversion of benzene alkylation with methanol to xylene. The effects of temperature, pressure, benzene/methanol molar ratio and weight hour space velocity(WHSV) on the catalytic performance of the catalyst were investigated as well. As a result, the high-silica hierarchical porous ZSM-5 showed great performance as the yield of xylene was up to 41.1% under the optimum reaction conditions(500 ℃,0.1 MPa,M_(benzene)/M_(methanol)= 1:1.5 and WHSV=4 h 1), while the selectivity to by-product, ethylbenzene, was well suppressed(below 0.1%). In addition, the catalyst structure and properties were characterized by the means of XRD, IR, TPD,SEM, TEM and N_2 physical adsorption technologies.