Rh-PPh3-polymer@mesosilica composite catalyst for the hydroformylation of 1-octene

Abstract

Rh-PPh3-polymer@mesosilica composites were prepared by the polymerization of mixtures of divinylbenzene (DVB) and 4-vinyl-triphenylphosphine monomer in the nanopores of mesoporous silicas followed by coordination with Rh(acac)(CO)2 (acac =acetylacetonate). These catalysts were characterized by XRD, N2 sorption, TEM, FT-IR, and TG, and could efficiently catalyze the hydroformylation of 1-octene with higher activity than a pure polymer catalyst because of their high surface area and large pore volume, which were beneficial for the exposure of active sites and mass transport. Through the control of pore size and pore connectivity by using different mesoporous silica (MCM-41, SBA-15, and FDU-12), the activity and selectivity can be controlled. Rh-PPh3-polymer@FDU-12 with a cage-like mesostrucuture showed lower activity but slightly higher selectivity than the catalyst with a 2-D hexagonal mesostructure (Rh-PPh3-polymer@SBA-15 or Rh-PPh3-polymer@MCM-41). By varying the polymer content in the nanopores of the mesosilica, the activity and selectivity (92%–96%) can also be tuned. The solid composite catalyst can be recycled without loss of activity, but a decrease in selectivity was observed.