The Cobalt Carbonyl-catalyzed Hydroesterification of Butadiene with Carbon Monoxide and Methanol

Abstract

The cobalt carbonyl-catalyzed hydromethoxycarbonylation of butadiene is studied. The reaction proceeds in the presence of a pyridine base to give methyl 3-pentenoate. Isoquinoline is found to be a better solvent for the production of methyl 3-pentenoate than pyridine, not only because the yield of the ester is somewhat higher in the presence of isoquinoline than in the presence of pyridine, but also because it is far less volatile than pyridine, so that the product can be easily separated from the solvent and the catalyst by distillation. Also, the hydromethoxycarbonylation of methyl 3-pentenoate under somewhat different conditions is found to give a good yield of dimethyl adipate. The hydroformylation of methyl 3-pentenoate is studied as well. The effect of such a solvent as THF, benzene, and acetonitrile in increasing the selectivity to methyl 5-formylpentanoate is found to increase in this order: acetonitrile<benzene<THF.