The Reaction Products of the Hydroformylation of Acrolein Acetals and Acetates

Abstract

Abstract The hydroformylation reactions of acrolein acetals and acetates were carried out in order to discuss the side reactions and any subsequent reactions. Acrolein cyclic acetals reacted with carbon monoxide and hydrogen in the presence of a dicobalt octacarbonyl catalyst to give n- and iso-aldehydes in a 2:1 ratio; they gave no further reaction products. Acrolein diethylacetal underwent hydroformylation using a rhodium catalyst to give n- and iso-aldehydes in a 1:2 ratio. In the presence of a cobalt catalyst, however, various products were obtained. As a result of the acidity of cobalt hydrocarbonyl and a high reaction temperature, n-aldehyde, first formed in benzene, underwent change to 2,5-diethoxytetrahydrofuran and 1,1,4-triethoxybutane. In ethanol, n- and iso-aldehydes gave the corresponding acetals. In the hydroformylation of acrolein acetate, only n-aldehyde was obtained. Iso-aldehyde seemed to be converted into 2-methyl-3-acetoxyacrolein by deacetylation. In ethanol, besides n-acetal, iso-acetal and propionaldehyde acetate, 2,5-diethoxytetrahydrofuran and 2-methyl-3-ethoxyacrolein were recognized. The former seemed to be formed from n-aldehyde by ring closure and ethanolysis. The latter seemed to be formed by the ethanolysis of 2-methyl-3-acetoxyacrolein. In ethyl orthoformate, no side reaction was observed and the yield of the main product, 1,1-diacetoxy-4,4-diethoxybutane, amounted to 80%.