Acid-Catalytic Effect of Alcohol Dissociation on Pinacol Rearrangement in Hot Compressed Water

Abstract

The acid-catalytic effect of alcohol on pinacol rearrangement in hot compressed water was investigated at temperatures ranging from 210 to 270 °C and a pressure of 30 MPa. The reaction order in hot compressed water depended on the pH. Kinetic analysis was conducted based on the reaction pathway, including the dissociation of pinacol. The reaction was found to be mainly catalyzed by H + produced from the dissociation of both water and pinacol. The kinetic analysis indicated that the dissociation constant of pinacol in hot compressed water was approximately 10 6 times higher than that in ambient water. Moreover, the acid-catalytic effect of pinacol increased with an increasing concentration and was greater than that of water.