Kinetics of synthesis of bis‐(benzoxazolyl‐2‐methyl) sulfide under phase‐transfer catalysis conditions

Kinetics of synthesis of bis‐(benzoxazolyl‐2‐methyl) sulfide (BBMS) is investigated under phase‐transfer catalysis conditions. Thus, the reaction of 2‐chloromethylbenzoxazole and sodium sulfide is carried out in a two‐phase (organic/water) medium, and quaternary ammonium salt and quaternary phosphonium salt are used as phase‐transfer catalyst (PTC) in the reaction. The conversion of 2‐chloromethylbenzoxazole is dramatically enhanced by adding a small quantity of PTC and is also greatly affected by the reaction conditions. The effects of various reaction variables on the kinetics are investigated, including the amount of catalyst, the temperature, the kinds of catalysts, the kinds of solvents, and the agitation speed. An interfacial reaction mechanism is proposed to explain the characteristics of the reaction. A pseudo‐first‐order rate model is established to describe the relationship between the fractional conversion and the reaction time. The kinetics data demonstrate that the model is suitable to the reaction of synthesis of BBMS. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 41: 296–302, 2009