New approaches to studying the kinetics of the radical reaction of N-phenyl-1,4-benzoquinone monoimine with 2-mercaptobenzothiazole

The kinetics of the reaction of N-phenyl-1,4-benzoquinone monoimine with 2-mercaptobenzothiazole in chlorobenzene at 298 and 343 K under argon has been studied by kinetic spectrophotometry. The reaction orders have been determined. The influence of tetraphenylhydrazine and azobisisobutyronitrile initiators has been investigated. An accelerating effect of one of the reaction products, 4-hydroxydiphenylamine, has been discovered. The accelerating effect strenthens with an increasing 2-mercaptobenzothiazole concentration. Two methods are proposed for determination of the kinetic parameters of the reaction. The first method uses data on the consumption rate of quinoneimine in the noninitiated reaction in the presence of 4-hydroxydiphenylamine. In the second method, the accumulation of quinone monoimine is studied during initiator decomposition in the presence of mixtures of 4-hydroxydiphenylamine and 2-mercaptobenzothiazole and parameters are estimated from the dependences of the limiting concentration of accumulated quinone monoimine on the initiation rate and on the concentrations of the reactants Using the proposed approaches, the numerical values of a number of kinetic parameters of the radical reactions of the quinone compounds with thiols have been determined for the first time for the reaction studied.