Heterogeneous hydroformylation of long-chain alkenes in IL-in-oil Pickering emulsion

Abstract

An efficient heterogeneous catalytic system for hydroformylation of long-chain alkenes is highly desirable for both academy and industry. In this study, an IL-in-oil Pickering emulsion system was employed for heterogeneous hydroformylation of 1-dodecene with Rh-sulfoxantphos as the catalyst and surface modified dendritic mesoporous silica nanospheres (DMSN) as the stabilizer. The IL-in-oil Pickering emulsion system outperformed IL-oil biphase, water-in-oil Pickering emulsion and IL-oil micelle system under similar reaction conditions to afford n/b ratio of 98 : 2, chemoselectivity of 94% and TOF of 413 h⁻¹, among the highest ever reported for IL-oil biphase hydroformylation of long-chain alkenes. The high efficiency of IL-in-oil Pickering emulsion was primarily attributed to the increased interface area and unique properties of ILs. Studies also revealed that solid stabilizers with large and open pore channels could greatly increase the reaction rate of Pickering emulsion systems by accelerating the diffusion rate. The recyclable IL-in-oil Pickering emulsion is promising not only for hydroformylation of long-chain alkenes but also for catalytic reactions with immiscible liquids.