Continuous Hydroformylation with Phosphine-Functionalized Polydimethylsiloxane Rhodium Complexes as Nanofilterable Homogeneous Catalysts

Abstract

Commercially available polydimethylsiloxane (PDMS) was functionalized with phosphine and used to form a Rh complex catalyst. The PDMS-based Rh catalyst complex shows promise as an inexpensive, readily synthesized and nanofilterable homogeneous catalyst for performing continuous hydroformylation. Batch hydroformylation of several substrates including 1-octene, 1-decene, 1-dodecene and styrene showed good activity and selectivity. For 1-octene hydroformylation, the observed catalyst activity with the PDMS-based Rh complex is 2-fold greater compared to that with a conventional Rh-triphenylphosphine complex under similar conditions. Continuous 1-octene hydroformylation for up to 120 h was demonstrated in a membrane nanofiltration system, showing stable conversion (∼60%) and high chemoselectivity (>95%). The total turnover number (TON) after 120 h was approximately 12 000 and the permeate Rh concentration was <2 ppm.