作者:Han Joong Koh、Suk Jin Kang
DOI:10.5012/bkcs.2012.33.12.4117
日期:2012.12.20
The solvolysis rate constants of allyl chloroformate ($CH_2=CHCH_2OCOCl$, 3) in 30 different solvents are well correlated with the extended Grunwald-Winstein equation, using the $N_T$ solvent nucleophilicity scale and $Y_Cl}$ solvent ionizing scale, with the sensitivity values of $0.93\pm}0.05$ and $0.41\pm}0.02$ for l and m, respectively. These l and m values can be considered to support a $S_N2$ reaction pathway. The activation enthalpies ($\Delta}H^\neq}$) were 12.5 to 13.4 $kcal\cdot}mol^-1}$ and the activation entropies ($\Delta}S^\neq}$) were -34.4 to -37.3 $cal\cdot}mol^-1}\cdot}K^-1}$, 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 $S_N2$ 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.
丙烯氯酸酯($CH_2=CHCH_2OCOCl$, 3)在30种不同溶剂中的溶解反应速率常数与扩展的Grunwald-Winstein方程有很好的相关性,使用了 溶剂亲核性尺度和 溶剂电离尺度,其灵敏度值分别为<0.93\pm}0.05> 和<0.41\pm}0.02>。这些 l 和 m 值可以被视为支持 $S_N2$ 反应途径。活化焓($\Delta}H^\neq}$)为12.5到13.4 $kcal\cdot}mol^-1}$,活化熵($\Delta}S^\neq}$)为-34.4到-37.3 $cal\cdot}mol^-1}\cdot}K^-1}$,这也与所提议的双分子反应机制一致。溶剂动力学同位素效应(SKIE,$k_MeOH}/k_MeOD}$)为2.16,也符合 $S_N2$ 机制。在醇/水混合物中3的溶解反应的产物选择性值(S)为1.3到3.9,这也与所提议的双分子反应机制一致。