The Liquid Phase Oxidation of Acrolein. IV. A Postulated Configuration of the Divalent Cobalt Acetylacetonate Catalysts in the Initiation Reaction

Abstract

Abstract A possible configuration of the pale blue precipitated divalent cobalt catalyst, synthesized by the addition of a saturated solution of deionized water in acrolein to a vigorously stirred solution of Co(acac)2 in benzene, is deduced from the infrared spectrum and thermal analyses; it is considered to be Co(acac)2-H2O-acrolein, in which acrolein is coordinated through its aldehyde oxygen. When the precipitated catalyst is used in the oxidation of acrolein, the induction period of oxygen absorption is shorter, the rate of oxygen absorption is higher, and the amount of oxygen absorbed is more than when any other divalent cobalt-acetyl-acetonate are employed. From these results, it is considered that the precipitated catalyst contains a species which is converted into a more active trivalent form faster than the other divalent catalysts. Furthermore, Co(acac)2 and Co(acac)2·2H2O are considered to take part in the oxidation via Co(acac)2-H2O-acrolein.