One pot synthesis of phenyl acetate and o-hydroxyacetophenone via esterification and fries rearrangement over zeolite catalysts

Abstract Acylation of phenol over zeolites (Y, s and ZSM5) and their protonated forms as catalysts has been investigated. The catalytic activity studies have been conducted both in liquid and gas phases. Acetic acid and acetic anhydride have been used as the acylating agents. The catalytic activity of other solid acids such as A1 2 O 3 , SiO 2 and ZrO 2 have also been studied and compared with that of zeolites. The results have been found to be interesting. In the liquid phase reactions all the catalysts i.e., zeolites, protonated zeolites and the oxides exhibited 100% selectivity towards the formation of only phenyl acetate (via O-acylation) as the product. However, vapour phase reactions revealed different results. Zeolite catalysts formed phenyl acetate followed by the Fries rearrangement to yield o-hydroxyacetophenone, when acetic acid is used as the acylating agent. Acetic anhydride on the other hand resulted in addition p-hydroxyacetophenone also. H-ZSM5 exhibited highest activity towards the formation of o-hydroxyacetophenone. Reaction conditions have been optimized to get good yield & selectivity of the desired products. Studies on catalyst deactivation indicated a stable activity over 120 minutes.