Characteristics of third phase for reaction of benzyl chloride with sodium sulfide in phase transfer catalytic system

The purpose of this study is to investigate how the property of third phase affects the reaction rate in a phase transfer catalytic reaction system. Dibenzyl sulfide was produced by the reaction between sodium sulfide in an aqueous phase and benzyl chloride in an organic phase by using tetrahexylammonium bromide ((Hex)(4)NBr) as a phase transfer catalyst. As the concentration of sodium sulfide in the aqueous phase and the temperature increased, the third phase was more easily formed. Three types for temperature dependencies on the reaction rate were observed. The reaction rate in one type initially increased, suddenly decreased, and then increased again. The other reaction rates in two types increased with the increase in temperature but the difference between them was 20-50 times at the same temperature. These behaviors could be explained by the property of third phase, especially, the lipophilicity or the hydrophilicity. (C) 2000 Elsevier Science B.V. All rights reserved.