Effect of pressure on the solvolysis of benzyl chloride in glycerol-water mixtures

The effect of pressure up to 1.6 kbar on the rate of solvolysis of benzyl chloride in 0 to 75% v/v glycerol-water has been measured at 50 °C. The volume of activation is −10.7 ± ~ 0.4 cm 3 mole −1 , essentially independent of solvent composition. Therefore, the partial volumes of both benzyl chloride and the transition state depend on solvent composition in the same way. The constant-volume energy and entropy of activation are simple functions of the solvent composition, and resemble the constant-volume parameters in ethanol-water mixtures. It is concluded that constant-volume conditions are probably more appropriate than constant-pressure conditions for discussing the solvent dependence of these solvolyses.