Thermodynamic and kinetic aspects of epichlorohydrin acetolysis under catalysis by triethylamine in solvents of various polarities

Abstract

The ring-opening reaction of epichlorohydrin with acetic acid in aprotic solvents under the catalysis by triethylamine in the temperature range of 313–353 K was studied by methods of chemical kinetics. The binary mixtures epichlorohydrin:tetrahydrofuran and epichlorohydrin:nitrobenzene (1:1 vol.) were chosen as solvents, which allowed preserving a significant excess of epichlorohydrin in the reaction system and varying the solvent polarity in the range of =15.1–28.7. The kinetic law of the reaction was established for the studied reaction series, and the observed and catalytic constants were obtained for epichlorohydrin acetolysis. It was demonstrated that the increase in temperature and solvent polarity accelerates the reaction. The temperature dependences plotted in Arrhenius coordinates exhibited linear behavior. The joint effect of temperature and solvents on activation parameters (energy, enthalpy, entropy, and Gibbs energy) of the reaction was investigated. The values of Gibbs energy of activation were found to be similar in all studied reaction systems. The isokinetic temperature of the epichlorohydrin acetolysis in epichlorohydrin and binary solvents epichlorohydrin:tetrahydrofuran and epichlorohydrin:nitrobenzene was established, and the enthalpy–entropy compensation effect was stated by correlation methods.