Three phase catalytic reactions: role of omega aqueous phase in solid-liquid phase transfer catalyzed etherification of 2'-hydroxy acetophenone

Abstract

Phase Transfer Catalyst (PTC) is used in more than 600 commercial processes, with wide ranging applications in the pharmaceuticals, agrochemicals, polymer industries. Despite thousands of publications on the PTC, several intricacies of PTC in reactions are not understood or properly modeled. Liquid-liquid (L-L) PTC is inferior to solid-liquid (S-L) phase transfer catalyzed reactions, which in turn can be converted into Solid (reactant)-Liquid-(aqueous omega)- Liquid (organic) using trace quantities of water to realize 100% selectivity to the product. There is great enhancement in rates of reactions in comparison with corresponding S-L or L-L PTC. Thus, the O-alkylation of sodium salt of 2'-hydroxy acetophenone was achieved using 1-bromopentane using tetrabutylammonium bromide as the catalyst at 90 0C.2-Pentyloxy acetophenone is used as a starting material for synthesis of fungicides. The current study deals with the efficacy of so-called omega phase with special emphasis on kinetic and modeling aspects.