Mechanism of the acidic hydrolysis of epichlorohydrin

The present studies show that the currently accepted scheme for the hydrolysis of epichlorohydrin (ECH) needs to be extended by an additional path which makes allowance for the formation and decomposition of glycidol (GL). It was shown experimentally and through UB3LYP/6‐11 + +G(3D,P) calculations that the formation of 3‐chloro‐1,2‐propanediol (MCPD) from ECH should also take into account GL formation as an intermediate product. A modified mechanism for the course of ECH hydrolysis in acidic and neutral medium is proposed. It was shown that ECH hydrolysis in acidic medium in the presence of chloride ions also results in the formation of 1,3‐dichloro‐2‐propanol (DCPD) in addition to GL and MCPD. The possibility of a parallel pathway for water molecule addition to epichlorohydrin was shown which as a consequence led to the parallel appearance of GL and MCPD. It was confirmed by kinetic calculations that the state of equilibrium, reached in the process of ECH chlorination, did not result in GL formation. However, its appearance in the reaction mechanism has been ignored in the literature thus far. Copyright © 2011 John Wiley & Sons, Ltd.