Effect of solvent on the kinetics of the reaction between dialkylbenzimidamides and 4-nitrophenylnitromethane
作者:Colin D. Hubbard、Delbert L. Harris、David W. Hooper、Arthur F. Tucci
DOI:10.1039/f19827803619
日期:——
for the proton-transfer reaction of 4-nitrophenylnitromethane, NO2C6H4CH2NO2, with two NN-dialkylbenzimidamides, HNC(C6H5)NR2, where R = 1-butyl, or 1-propyl, in the temperature range 273–303 K in some aprotic solvents of low polarity. In the concentration ranges used the reaction to form an ion-pair product is first-order in acid and first-order in benzimidamide. The reactions were monitored spectrophotometrically
已经确定了4-硝基苯基硝基甲烷,NO 2 C 6 H 4 CH 2 NO 2与两种NN-二烷基苯甲酰胺,HN C(C 6 H 5)NR 2的质子转移反应的速率常数。在一些低极性非质子传递溶剂中,在273–303 K的温度范围内,R = 1-丁基或1-丙基。在所使用的浓度范围内,形成离子对产物的反应在酸中为一级,在苯并咪酰胺中为一级。反应采用分流光度法分光光度法监测。在六种溶剂中,在298 K下正向质子转移速率常数的关系对于二丁基化合物而言,与溶剂介电常数函数和溶剂极性参数(E T)表明形成了极性活化的复合物; 这与产生离子的反应相容。在三种溶剂中二丙基类似物的相应动力学参数与此模式一致。对苯并咪酰胺中烷基变化的动力学参数没有显着影响。正向质子传递的活化能很小,在10–23 kJ mol –1范围内,而反方向的活化能在65–114 kJ mol –1范围内。使用正向速率常数和在298 K下导