Kinetic study of the reactions of 1,1-diphenylallene in ethanol in the presence of sodium ethoxide

Abstract

The rates of dimerisation and of ethoxide-ion addition of 1,1-diphenylallene in ethanol at temperatures from 70 to 100° have been measured by gas-chromatographic analysis. Second-order rate constants for the concurrent reactions (of type A + A and A + B, respectively) have been derived. It has been confirmed that 2-chloro- and 2-bromo-1,1-diphenylpropene react with ethoxide ion with diphenylallene as an intermediate. The rate constants, separately determined for the stages of the system of consecutive-competitive reactions, account well for the experimental concentration–time results of the complete system.