Vapor-phase tertiary butylation of phenol over mesoporous gallosilicate molecular sieves

Abstract

Isomorphously substituted Ga-MCM-41 molecular sieves with different Si:Ga ratio were synthesized and characterized systematically by various analytical and spectroscopic techniques. Temperature programmed desorption of ammonia was used to identify the nature of acidic sites. For the first time, the vapor-phase tertiary butylation of phenol reaction was carried out over protonated GaMCM-41. The catalysts showed higher(phenol) conversion and good (para tertiary-butyl phenol) selectivity over the Al and Fe-analogs of MCM-41. Further the gallosilicates showed good stability both before and after the reaction compared to the aluminosilicates and ferrosilicates.