Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only
Publication Acceptance Date: January 15, 2004
Publication Date: May 1, 2004
Citation: Piazza, G.J., Nunez, A., Foglia, T.A. 2004. Fatty epoxide synthesis with peroxygenase and hydrolysis with alumina and perchloric acid [abstract]. 95th Annual Meeting of the American Oil Chemists' Society. p. 28. Technical Abstract: Polyhydroxy fatty acids and esters are known to be natural metabolites in both plants and animals and their chemical derivatives may have commercial uses as natural emulsifiers and surfactants in a variety of functional areas. A main route for the chemical synthesis and biosynthesis of these polyhydroxy materials is through the hydrolysis of epoxides formed from the double bond oxidation of unsaturated fatty materials. We had been studying the promotion of fatty epoxide formation using chemical catalysts and the enzyme peroxygenase from oat seeds, and we were interested in determining the chemical structure of epoxide hydrolysis products. We used perchloric acid and neutral alumina to promote hydrolysis. Structural analysis of the product of methyl 9,10-epoxyoctadecanoate (methyl epoxystearate) hydrolysis showed that the threo isomer of methyl 9,10-dihydroxyoctadecanoate was produced by both acid and alumina. Thus fatty epoxide hydrolysis in this example proceeds by a concerted SN2 type mechanism. We subjected methyl 9,10-12,13-diepoxyoctadecanoate (methyl diepoxystearate) to the action of both neutral alumina and perchloric acid. It was found that two regioisomeric tetrahydrofuran products were produced: methyl 9,12-epoxy-10,13-dihydroxystearate and methyl 10,13-epoxy-9,12-dihydroxystearate. Thus perchloric acid and neutral alumina induce chemical rearrangement leading to dihydroxyfuran products. These are somewhat less polar than a tetrahydroxy hydrolysis product that would be expected without rearrangement, and the results demonstrate that complete structural analysis of lipid products is an important part of the rational design of biobased chemical products for specific industrial uses.