Rate and Product Studies on the Solvolyses of Allyl Chloroforniate

摘要

The solvolysis rate constants of allyl chloroforniate (CH2=CHCH2OCOCl, 3) in 30 different solvents are well correlated with the extended Grunwald-Winstein equation, using the N_t solvent nucleophilicity scale and Y_(C1) solvent ionizing scale, with the sensitivity values of 0.93 ± 0.05 and 0.41 ± 0.02 for / and m, respectively. These l and m values can be considered to support a S_n2 reaction pathway. The activation enthalpies (A/7) were 12.5 to 13.4 kcal-mol~(-1) and the activation entropies (AS) were -34.4 to -37.3 cal·mol~(-1)·K~(-1), which is also consistent with the proposed bimolecular reaction mechanism. The solvent kinetic isotope effect (SKIE, k_(MeOH)/k_(MeOD)) of 2.16 was also in accord with the Sn2 mechanism. The values of product selectivity (S) for the solvolyses of 3 in alcohol/water mixtures was 1.3 to 3.9, which is also consistent with the proposed bimolecular reaction mechanism.