Kinetic Studies on the Reaction of Terephthalic Acid with Ethylene Oxide to Form Ether Linkage

Abstract

Kinetic studies on the reaction of terephthalic acid with ethylene oxide to form bis[2- (2- hydroxyethoxy) ethyl] terephthalate (BEET) were made in the presence of quaternary ammonium terephthalate (HOOC-C6H₄-000eN0 (C₂H₅) 3C₂H₄0H) in nitrobenzene. When an excess of ethylene oxide was allowed to react with terephthalic acid, esterification of terephthalic acid proceeded in the initial stage, then hydroxyl groups, generated in the initial stage, reacted with ethylene oxide to give BEET.
Such an etherification already proceeded in the initial stage as a side reaction and yielded small amounts of BEET. It was concluded that this reaction proceeded in terms of two different mechanisms depending upon the presence or absence of terephthalic acid in the presence of terephthalic acid free hydroxyl groups reacted directly with ethylene oxide, forming hydrogen bonding with acid or alcohol, to form ether linkage while in the absence of terephthalic acid occurring after its consumption, quaternary ammonium alkoxide (HOC₂H₄0OC-C6H₄-COOC₂H₄09N(C₂1-15) 3C, H₂OH) reacted with activated ethylene oxide.