Abstract
The catalytic addition reaction of maleic anhydride to castor fatty acids or their methyl esters by flow method was investigated. It is found that the synthetic silica-alumina composed of 70% of SiO2 and 29% of Al2O3 has high catalytic activity for the addition reaction of maleic anhydride to castor fatty acid methyl esters and that the addition to castor fatty acids is also easily carrieds out by continuously passing the mixed solution of maleic anhydride and castor fatty acids over a catalyst having phosphoric acid deposited on the silica-alumina as a carrier.
The adduct separated by column chromatography was known to be predominantly consisted of the fatty acids and maleic anhydride at a proportion of 1 : 1 and to have a cyclohexene ring structure by IR, NMR, and MS spectral analysis. Then, the addition reaction was considered to be based on the Diels-Alder addition reaction of maleic anhydride to conjugated octadecadienoic acids produced with the dehydration of ricinoleic acid by the catalyst.
