The Cobalt Carbonyl-catalyzed Hydroesterification of Acrylonitrile with Carbon Monoxide and Methanol in the Presence of a Small Amount of Hydrogen and a Limited Amount of Pyridine

Abstract

The present reaction was studied in connection with our preceding research on the hydroesterification of propylene (This Bulletin, 38, 710 (1965)). The cobalt carbonyl-catalyzed reaction was successfully carried out in the presence of a small amount of hydrogen and a limited amount of pyridine; methyl esters of α- and β-cyanopropionic acids were thus obtained, the former in a larger amount than the latter. As the temperature decreased or as the partial pressure of carbon monoxide increased, the selectivity of the reaction toward the methyl α-cyanopropionate grew larger. The reaction mechanism was mainly investigated by kinetic methods. The infrared spectra of the catalyst solutions were measured at −60°C with a low-temperature cell. It was found by the IR study that acylcobalt carbonyls were formed in the acrylonitrile solution of dicobalt octacarbonyl and pyridine when it was treated under the same conditions (temperature and pressure) as in the reaction. It was found from the results of kinetic studies that the mechanisms of reactions at temperatures above and below 100°C were different; each of these mechanisms was discussed.