Mechanism and kinetics of liquid-liquid solid-phase transfer catalysis

IEC 185

Ganapati D. Yadav and Suguna S. Naik. Department of Chemical Engineering, Mumbai University Institute of Chemical Technology, Nathalal Parekh Road, Matunga, Mumbai, 400019, India
The drawbacks associated with the recovery and reuse of expensive phase transfer catalysts and avoiding waste are overcome by supporting the catalyst on a suitable solid matrix. Quaternary ammonium salts, phosphonium salts, macrocyclic polyethers, polar solvent residues and/ or poly(ethylene glycols) immobilized on cross-linked polystyrene resins are effective catalysts for phase transfer reactions. These liquid-liquid-solid (L-L-S) PTC reactions are inherently slow due to intraparticle diffusion limitation and their mechanism is obscure. Despite of several attempts to analyse the kinetics and mechanisms of polymer supported PTC, there are several lacunae in published literature of the precise mechanism and kinetics. This work was undertaken to develop a mechanism and kinetics of L-L-S PTC by conducting the SN2 type of reaction between aqueous sodium azide and benzyl chloride located in the organic phase.So we have attempted to analyse the polymer supported PTC by using the concept of wettability of pore matrics and the exact locale of the reaction in them.