Nucleophilic Reactivities of Primary and Secondary Amines in Acetonitrile
作者:Tanja Kanzian、Tobias A. Nigst、Andreas Maier、Stefan Pichl、Herbert Mayr
DOI:10.1002/ejoc.200900925
日期:2009.12
kinetics of the reactions of primary and secondaryamines with benzhydrylium ions and quinone methides in acetonitrile have been studied under pseudo-first-order conditions (high excess of amines) by UV/Vis spectrophotometry. Generally, the plots of kobs versus amine concentration were linear, in line with a second-order rate law. However, for some reactions of secondaryamines with quinone methides, the
伯和仲胺与二苯甲基离子和醌甲基化物在乙腈中的反应动力学已通过紫外/可见分光光度法在准一级条件(胺过量)下进行研究。通常,kobs 对胺浓度的图是线性的,符合二阶速率定律。然而,对于仲胺与醌甲基化物的某些反应,kobs 与胺浓度的曲线显示向上弯曲,这表明初始形成的加合物被第二个胺分子限制速率去质子化。根据胺对亲电子试剂的攻击的二级速率常数 k2,胺的亲核性参数 N 和 s 由线性自由能关系 log k2 (20 °C) = s(N + E) 确定。