Simultaneous hypercrosslinking and functionalization of polyHIPEs for use as coarse powder catalyst supports

Abstract

Porous polymers offer desirable properties for heterogeneous catalysis, such as excellent stability, high active site density, and reusability. However, their synthesis is often complicated, requiring expensive reagents and laborious synthetic processes. We produce organophosphorus functionalized polyHIPEs by the polymerization of particle and surfactant stabilized water-in-styrene/divinylbenzene high internal phase emulsion templates, followed by post-functionalization using low-cost hypercrosslinking strategies. Three hypercrosslinking approaches were investigated, including knitting with an external crosslinker, solvent stitching and Scholl coupling reaction. Each approach’s ability to simultaneously create micro/mesoporosity and incorporate organophosphorus moieties into the polyHIPE structure as catalyst anchor sites were assessed, introducing surface areas of up to 410 m2/g and phosphorus concentrations of up to 7.4 wt%. After Pd-loading, the polyHIPEs displayed outstanding catalytic performance in a Suzuki-Miyaura coupling reaction, reaching turnover frequencies of 5722 h−1. The coarse powder form of the polyHIPEs allowed for simple catalyst recovery from the reaction mixture for reuse.