Rhodium-catalyzed hydroformylation in γ-valerolactone as a biomass-derived solvent

Abstract

Rhodium-catalyzed hydroformylation of styrene, α-methylstyrene, dimethyl itaconate, and (R)-limonene was performed in gamma-valerolactone (GVL) as a proposed biomass-based environmentally benign solvent for hydroformylation referring to toluene as a generally used conventional solvent. Both achiral (triphenylphosphine, 1,3-bis(diphenylphoshino)propane) and enantiopure bidentate phosphine ligands ((S,S)-BDPP, (R)-BINAP, (R)-QUINAP, (R,R)-DIOP, (Rc),(Sp)-JOSIPHOS, (S)-SEGPHOS, (S)-(DM)-SEGPHOS) were investigated in in situ generated Rh-diphosphine catalyst systems. In general, the catalysts' activity in GVL was lower than in toluene; however, remarkable chemo- (>99%) and regioselectivities (>95%) were achieved in GVL under identical conditions. The BDPP-modified Rh-catalyst was recycled for three consecutive cycles; however a decrease in its activity was detected.