Selective Synthesis of p‐Cresol by Alkylation of Phenol with Methanol over SiO2‐Modified HMCM‐22 Catalyst

Abstract

AbstractA series of xSiO2/HMCM‐22 were prepared by chemical liquid deposition of HMCM‐22 with tetraethyl orthosilicate and evaluated in the catalytic synthesis of p‐cresol by alkylation of phenol with methanol. Several characterization techniques including N2 adsorption‐desorption, X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FT‐IR), Pyridine‐IR, temperature‐programmed desorption of NH3 (NH3‐TPD) as well as the probe reaction of m‐xylene isomerization and 1,3,5‐triisopropyl benzene (1,3,5‐TIPB) cracking have been used to analyze the physicochemical properties of xSiO2/HMCM‐22 catalyst. The conversion of phenol decreased with increasing SiO2 loading of xSiO2/HCM‐22 catalyst; while the selectivity for p‐cresol maximized at x=1 %. The 1 %SiO2/HMCM‐22 catalyst was identified as the most efficient catalyst, showing the highest p‐cresol selectivity for longer than 15 h under optimized reaction conditions. The high p‐cresol selectivity of the catalyst is attributed to the fact that SiO2 covered the acid sites of the external surface of the HMCM‐22 and preserved the acid sites in the micropores of zeolite.