Al-MCM-41 catalysed alkylation of phenol with methanol

Mesoporous Al-MCM-41 molecular sieve materials with three different SiO2/Al2O3 ratios were used as catalysts for phenol methylation with methanol as the alkylating agent. Reaction conditions such as temperature, feed flow rate, the reactant mole ratio and the catalyst SiO2/Al2O3 ratio have significant influence on the distribution of products. The formation of the predominant product o-cresol was enhanced by lower temperature, less amount of alkylating agent in the feed and lower acidity of the catalyst with an optimum WHSV value of 1.78 h(-1). Higher acidity favoured the formation of C-alkylated products, while O-alkylation required lower acid strength of the catalyst. Formation of double alkylated products was associated with higher temperature, large contact time, excess of methanol in the feed and higher acid strength of the catalyst. (C) 2002 Elsevier Science B.V. All rights reserved.