Alkylation of phenol with methanol over zeolite H-MCM-22 for the formation of p-cresol

Abstract

The alkylation of phenol with methanol over H-MCM-22 was investigated and the performance of this catalyst compared with that of H-ZSM-5 and amorphous silica-alumina. The reaction was studied in the liquid phase (batch reactor) at temperatures between 200–250°C and pressures between 20–42 bar and in the gas phase (flow reactor) at temperatures between 250–400°C and feed partial pressures of 0.2 bar. The C (ring) : O (side chain)-alkylation ratio was found to be more dependent on reaction conditions (i.e. gas/liquid phase, pressure and temperature) than catalyst type. The highest C : O alkylation ratios were obtained using gas phase reactions and were similar for all three catalysts. The highest p/o -cresol ratios were obtained using H-MCM-22 in the liquid phase at 200°C. Reasons are proposed to explain the different ring vs side chain alkylation and cresol isomer distributions for the different catalysts and the different reaction conditions.