Effects of a composition of a binary solvent chlorobenzene—propan-1-ol on the mechanism of the reaction between N , N ’-diphenyl-1,4-benzoquinone diimine and thiophenol

The kinetics of the reaction of N,N’-diphenyl-1,4-beznoquinone diimine with thiophenol in a chlorobenzene—propan-1-ol binary solvent at 343 K was studied spectrophotometrically. The nature of the solvent has a pronounced effect on the reaction rate. On going from chlorobenzene to propan-1-ol, the overall reaction rate increases nearly by an order of magnitude. The reaction has a complex mechanism and follows the two directions. The first direction is the chain reaction with the rate increasing upon addition of an initiator. The second direction is non-chain reaction between the reagents; the initiator does not affect the rate of this reaction. A gross rate constant of the non-chain reaction and the rate constants of some elementary steps of the chain reaction were determined. Based on the obtained results, the overall reaction rate, the rates of both chain and non-chain reactions were calculated depending on the content of propan-1-ol in the binary solvent, concentration of the reagents, and the rate of initiating reaction induced by initiator. It is found that an increase in the propan-1-ol content increases the role of the non-chain process.