Reaction of Maleic Anhydride with Unsaturated Fatty Acids in the Presence of Organic Peroxides

Abstract

Reaction of maleic anhydride with linoleic and oleic acids in the presence of organic peroxides was investigated. The peroxides used were benzoyl peroxide (BPO), di-tert-butyl peroxide (DtBPO), and dicumyl peroxide (DCPO). The maleinization reaction was accelerated by the presence of organic peroxides, and was carried out at a temperature that the peroxides decompose (about 130°C). The orders of the activities of the reaction were as follows : (i) On the peroxides DCPO ≥ DtBPO >> BPO (ii) On the maleic anhydride and its related compounds maleic anhydride >> maleic acid > dimethyl fumarate ≥ fumaric acid > dimethyl maleate (iii) On fatty acids linoleic acid > oleic acidIn the case of the reaction of linoleic acid with maleic anhydride, a product of resinous powder (mp ; about 130°C) was obtained. On the structure of maleinized product it was presumed that the main product was dimer, crosslinked by maleic anhydride, of maleic anhydride added to linoleic acid (III), and that the by-product was ketonic compounds derived by decarboxylation from two acid anhydride groups in the main product (III).(III) From the results obtained, a biradical addition reaction mechanism was postulated.