respectively. The corresponding ρI values were 4.64, 4.94 and 3.64. The dependence of ρI on solvent and temperature in the alkaline hydrolysis of substituted alkyl benzoates was similar to that observed earlier for meta- and para-substituents in the alkaline hydrolysis of substituted phenyl benzoates and tosylates. The substituent dependence of the activation energy, E, was found to be completely caused by
碱性
水解取代的
苯甲酸烷基酯C 6 H 5 CO(O)R的二级速率常数k 2(M -1 s -1)(R = CH 3,CH 2 Cl,CH 2 CN,CH 2分别在2.25 M n -Bu 4 NBr
水溶液和80%(v / v)
DMSO溶液中测量C measuredCH ,CH 2 C 6 H 5,CH 2 CH 2 Cl,CH 2 CH 2 OCH 3)。 。日志k使用等式测井值进行了分析ķ =登录ķ 0 +ρσ+δ Ë小号乙。对于酯的烷基部分中的烷基取代基的空间效应,已经提出了E s B标度:E s B =(log k R -log k CH 3),其中k是取代烷基的酸性
水解速率常数
水中的
苯甲酸酯或
乙酸酯。作为极性取代参数,既塔夫特σ*和σ我使用的常量。使用σ和的log k值的双参数处理E s B常数给出了极好的相关性(R = 0.997)。对于2.25 M n -Bu 4