HYDROFORMYLATION OF ETHYL ACRYLATE CATALYZED BY RH(ACAC)(CO)2-PHOSPHORUS LIGAND SYSTEMS

In the hydroformylation of ethyl acrylate, Rh(acac)(CO)2-P(O-p-XC6H4)3 (X = H, Me, Cl) catalyst systems exhibit high activities under the co nditions 40-degrees-C and 1 atm of CO-H-2 (1:1), to give beta-formylpr opionate as the main product. Rh(acac)(CO)2-PR3 (R = Ph, Me) systems w ere almost inactive. When P(0-i-Pr)3 is used as the ligand, hydrogenat ion of the acrylate proceeds exclusively. The catalyst with P(OMe)3 or P(OCH2)3CEt mainly affords the alpha-formylated product, although its activity is much lower. Higher molar ratios of P/Rh up to about five, as well as higher catalyst concentration, are favorable for beta-form ylation in the Rh(acac)(CO)2-P(OPh)3 system. Raising the temperature a ccelerated hydrogenation with suppression of alpha-formylation. Increa sing the pressure of CO-H-2 causes selective formation of alpha-formyl propionate.