The darzens condensation. Part III. Effects of substituents on the rate of condensation of substituted phenacyl chlorides with benzaldehyde

Abstract

The rates of condensation of phenacyl chloride and its p-methyl, and p-chloro-derivatives with benzaldehyde were measured polarographically in methanol with sodium methoxide as catalyst, and in ethanol with hydrogen chloride gas as catalyst. A proposal is made for the mechanism and the rate-determining step in the acid-catalysed condensation. In both the base- and acid-catalysed reactions the rates were increased by electron-donating substituents. The Hammett relation is valid for the reaction.