Dual Optimization in Phase Transfer Catalyzed Synthesis of Dibenzyl Sulfide using Response Surface Methodology

Abstract

A new reaction protocol has been developed to prepare dibenzyl sulfide (DBS), a value-added organosulfur fine chemical, by utilizing toxic hydrogen sulfide (H2S). H2S absorbed in monoethanolamine (MEA) has been used as a sulfiding agent for benzyl chloride (BC) under liquid–liquid phase-transfer-catalyzed condition. Response surface methodology was used to model and optimize the process parameters for simultaneous dual-maximization of BC conversion and DBS selectivity. BC/sulfide mole ratio, MEA/sulfide mole ratio, temperature, and catalyst concentration were chosen as independent variables, and conversion of BC and selectivity of DBS were chosen as responses. A quadratic regression model was derived with satisfactory prediction. Dual optimization with desirability function predicts a maximum BC conversion of 100% and a maximum DBS selectivity of 95.2% under experimental conditions: temperature 353 K, catalyst concentration 0.14 kmol/m3, BC/sulfide mole ratio 2.83, MEA/sulfide mole ratio 3.7. The analysis...