Supported phosphotungstic acid catalyst on mesoporous carbon with bimodal pores: A superior catalyst for Friedel-Crafts alkenylation of aromatics with phenylacetylene

摘要

Supported phosphotungstic acid (PTA) catalysts on diverse carriers containing the modified commercially available activated carbon (AC), classical mesoporous carbon via SBA-15 hard template method (CMK-3), and the mesoporous carbon with high surface area and bimodal pores through evaporation induced tri-constituent co-assembly approach (MC) by using a facile wet impregnation method were employed as solid acid catalysts for Friedel-Crafts alkenylation of p-xylene with phenylacetylene. N-2 adsorption desorption, X-ray diffraction (XRD), and NH3 temperature-programmed desorption (NH3-TPD) characterization techniques were employed to reveal the structure-performance relationship. PTA/MC exhibits much superior catalytic performance to the previously reported PTA/AC, and even to PTA/CMK-3. The PTA/MC catalysts were optimized by varying the PTA loading, and the optimum PTA loading is 35%. The close to 100% of conversion towards phenylacetylene can be achieved in the presence of 2.67% of the 35% PTA/MC solid acid catalyst. It is also found that catalytic properties of the solid acids are strongly depended on acidic properties that affected by the textural properties of supports and PTA loading, as well as the accessibility of active sites affected by specific surface area and pore structure of catalyst. Moreover, the 35 wt.% PTA/MC catalyst has demonstrated outstanding catalytic performance for the Friedel-Crafts alkenylation of diverse aromatics to their corresponding alpha-arylstyrenes. (C) 2016 Elsevier B.V. All rights reserved.