Solvent and Structural Effects on the Activation Parameters of the Reaction of Carboxylic Acids with Diazodiphenylmethane

The kinetics of the reaction of benzoic, 2-methylbenzoic, phenylacetic, cyclohex-1-enecarboxylic, 2-methylcyclohex-1-enecarboxylic, and cyclohex-1-eneacetic acids with diazodiphenylmethane was studied at 30, 33, 37, 40, and 45 degrees C in a set of 12 protic and aprotic solvents. The reactions were found to follow the second-order kinetics. The activation energy as well as the activation parameters, such as the standard entropy, the standard enthalpy, and the standard Gibbs energy of the activation, was calculated from the second-order rate constants. The solvent and structural effects on the activation energy and the standard Gibbs energy of activation, for each examined compound, were analyzed. The results of KamletTaft multiple correlation analysis show that the specific solventsolute interactions play a dominant role in the governing of the reaction. The signs of the equation coefficients support the proposed reaction mechanism. (C) 2013 Wiley Periodicals, Inc. Int J Chem Kinet 45: 256-265, 2013