Kinetics and mechanism of the hydrolysis of substituted phenyl benzoates catalyzed by theo-iodosobenzoate anion
作者:Omar A. El Seoud、Monica F. Martins
DOI:10.1002/poc.610081003
日期:1995.10
The o-iodosobenzoate (IBA−)-catalyzed hydrolysis of the following esters was studied spectrophotometrically: 4-nitrophenyl 4-X-benzoate (series I, a–e, X = CH3, H, Cl, CN, NO2), 4-Y-phenyl 4-nitrobenzoate (series II, a–d, Y = CH3, H, Cl, CN), 2,4-dinitrophenyl 4-X-benzoate (series III, b–e, X = H, Cl, CN, NO2) and 4-Y-phenyl 2,4-dinitrobenzoate (series IV, a–e, Y = CH3, H, Cl, CN, NO2). Direct detection
的Ô -iodosobenzoate(IBA - )-催化以下的酯的水解用分光光度计研究:4-硝基苯基4-X-苯甲酸甲酯(系列I,A-E,X = CH 3,是H,Cl,CN,NO 2), 4-Y-苯基4-硝基苯甲酸酯(II系列,a–d,Y = CH 3,H,Cl,CN),2,4-二硝基苯基4-X-苯甲酸酯(III系列,b–e,X = H, Cl,CN,NO 2)和4-Y-苯基2,4-二硝基苯甲酸酯(系列IV,ae,Y = CH 3,H,Cl,CN,NO 2)。直接检测反应中间体,即1-(4-硝基苯甲酰氧基)-1,2-苯并三酚-3(1 H) -酮,由离去基团,该小的动力学溶剂同位素效应和快速催化剂“营业额”表明,催化由IBA的机构的情况下(一般碱)催化的-是亲核的。催化速率常数,活化参数和Hammett方程的应用表现出以下机理特征:反应的第一步,即导致上述中间体形成的反应是不可逆的,离去基团