Rates and temperature coefficients in resin-catalyzed hydrolysis of aliphatic esters

Rate constants for the resin-catalyzed hydrolysis of ethyl formate were determined in acetone-water mixtures for compositions varying from 0 to 45% acetone (V/V) at different temperatures ranging from 20 °C to 40 °C. The experimental results indicated a linear dependence of the logarithm of rate constant on the reciprocal of the dielectric constant. For solutions of the same composition, the activation energy, EC, tends to decrease as the acetone content increases, while for solutions of the same dielectric constant, the activation energy, ED, increases as the dielectric constant of the solvent increases. The trends of variation of the activation parameters are correlated with the solvantion mechaninism and dielectric behavior of the medium. The linear plot of TδS* against δH* represents what is known as the “compensation effect”.