The influence of the solvent on organic reactivity. Part 5. Kinetics of the reaction of diazodiphenylmethane with benzoic acid in branched-chain alkanols and in electronegatively substituted alcohols

Abstract

Rate coefficients at 30.0 °C are presented for the reaction of diazodiphenylmethane and benzoic acid in five branched-chain alkanols and in nine electronegatively substituted alcohols. As in earlier work, correlation analysis of log k values involves multiple regression on the σ* value of the group R¹ in the alcohol R¹OH, the Kirkwood function of dielectric constant f(ε)=(ε– 1)/(2ε+ 1), and n_γH, the number of hydrogen atoms in the γ-position of the alcohol. The results for branched-chain alcohols provide further examples of the acceleratory effect of γ-hydrogen atoms. A correlation equation based on 27 alkanols and phenyl-substituted alcohols, for which σ* lies between –0.325 and +0.215, can be applied with reasonable success to seven electronegatively substituted alcohols, for which σ* lies in the range 0.07–0.92. 2-Methoxy- and 2-phenoxy-ethanol show marked deviations. Correlation equations properly incorporating the data for the electronegatively substituted alcohols are finally presented.