In situ generated micro-catalytic system for the epoxidation of allyl chloride with hydrogen peroxide

Abstract

The epoxidation of allyl chloride and H2O2 catalyzed by heterogeneous catalyst suffers from inadequate mixing between organic phase, aqueous phase and solid catalyst. This work describes a novel micro-catalytic system for the intensification of this multiphase reaction process. Aqueous phase is capsulated with the loaded phosphotungsten heteropoly acid catalyst to produce microdroplets in situ, the oil-water interface consisting of the catalyst particles facilitates the epoxidation reaction. The regulation of microdroplet size can be achieved by changing the hydrophobicity of the catalyst surface, with a suitable hydrophobicity reducing the diameter of microdroplets and exhibiting optimal catalytic activity. The ECH conversion and selectivity in the micro-catalytic system can be reached as high as 98.02 % and 99 %, respectively. The structure and stability of the catalyst are illustrated by SEM, XPS, FT-IR and TGA. Furthermore, inexpensive commercial polystyrene was used as catalyst carriers, and the synthesis process of the catalyst is simple, which enables the large-scale synthesis of the catalyst. This strategy is a promising approach to designing catalysts for oil-water multiphase reactions.