Proximity effect on the general base catalysed hydrolysis of amide linkage: The role of cationic surfactant, CTABr
作者:SARAT C DASH、ANADI C DASH
DOI:10.1007/s12039-011-0084-5
日期:2011.7
transition states which can be assembled by favourably oriented phenoxide groups. The solvent kinetic isotope effect for I, k H2O/k D2O + H2O ~1 (20 and 50 volume% D2O), indicates that proton transfer is not involved as a part of the rate controlling process. The observed slowing down of the rate of this reaction for I in the micellar pseudo phase of CTABr also supports the proposed mechanism. Under pre-micellar
(1,2)双(2-羟基苯甲酰胺基)乙烷(I),(1,5)双(2-羟基苯甲酰胺基)3-氮杂戊烷(II),(1,3)双(2-羟基苯甲酰胺基)的双酚盐形式丙烷(III),和(1,8)双(2-羟基苯甲酰胺基)-3,6-二氮辛烷(IV)进行酰胺基团中的一个(0.02≤[OH的容易水解 - ] Ť(摩尔分米 - 3)≤0.5 ,10%甲醇(体积/体积)+ H 2 o中)而不表现出[OH - ]的依赖性。反应性趋势遵循我〜II >> III〜IV具有低活化焓25.7±2.8≤ΔH ≠(千焦耳摩尔 - 1)≤64.8±7.0}。较高的活化熵负值和可比较的活化熵-234±8≤ΔS ≠(JK -1 mol -1)≤-127±20}与紧密相似且有序的跃迁状态相一致,可以通过取向良好的苯酚基团进行组装。为溶剂动力学同位素效应我,ķ H2O / ķ D2O + H 2 O〜1(20和50%(体积)d 2