Kinetic modeling on ionic liquid mediated bi-liquid phase transfer catalyzed synthesis of bis-(2-phenylethyl) sulfide with H2S-rich methyldiethanolamine.

Abstract A kinetic investigation was carried out on the utilization of H 2 S for the synthesis of bis-(2-phenylethyl) sulfide (PES) using ionic liquid catalyst trihexyltetradecylphosphonium chloride as a phase transfer catalyst. The method involved the absorption of H 2 S into aqueous N -methyldiethanolamine (MDEA) which is followed by reaction of this aqueous H 2 S-laden MDEA with organic reactant 2-bromoethylbenzene (2-BEB) to yield PES under liquid–liquid (L–L) phase transfer catalytic condition. The effect of various reaction parameters on the conversion of 2-BEB was studied and the product selectivity was found as 100%. A suitable reaction mechanism involving the possible paths of product formation was proposed. A novel mathematical model was developed to explain the experimental findings. This method will be helpful in overcoming the cost of disposal of organic solvents which have been used often in multiphase organic synthesis. Graphical abstract Unlabelled Image Highlights • An Ionic liquid catalyzes thioetherification of an aromatic halide utilizing H 2 S. • 100% selectivity of thioethers observed with high reaction rate and conversion. • Hydrosulfide found to be main species involved in reaction media. • Kinetic modeling successfully explained the mechanism and kinetics data. • The process can be used an alternative to Claus process. [ABSTRACT FROM AUTHOR]