Syntheses and Reactions of Rhodium-Acrolein Complexes

Abstract

New rhodium-acrolein complexes were obtained by the reaction of bis(cyclooctene)chloro, rhodium, [RhCl(CsHM)2]2 (1), with acrolein in the presence of 1, 2-bis(diphenylphos. phino)ethane (DPE) or ev, adipyridy1 (Dipy). Reaction with DPE gave a yellow crystalline. complex, Rh(COCI) (CH2=CH2) (CH2=CHCHO) (DPE) (2), which was presumed to have Rh-COCl bonds. (2) reacted with triphenylphosphine to give RhCI(CO) (PPh3)2 evolving ethylene gas. Red crystalline complex, [RhCl(DPE)]2, was obtained by recrystallization of -(2) tr. oAm.5cetone or h6t benzene. By use of Dipy instead of DPE, . a brown powder complex, RhCl (CH2=CHCHO)2 (Dipy) (3), was obtainedl The same complex (3) was also obta. ined by tT??@feaction of rhodium-acroleitn complex, RhCl(CH2=CH2) (CO) (CH2=CHCHO), with Dipy. However, the reaction of rhodium-acrolein complex with DPE did not yield the abovet copaplgx (2), but RhCl(DPE)2 or [RhCl(DPE)]2. These rhodium-acrolein-complexes-gatalyged. th e forination of diethyl ketone and ethyl vinyl ketone from acrolein, carbon monoxide and ethylene in low yield.