Method for preparing conjugated polyunsaturated fatty acid esters

Abstract

The claimed method for preparing conjugated polyunsaturated fatty acid esters consisting of an alcohol radical R1 having from 1 to 5 carbon atoms and a fatty acid radical R2 having from 10 to 24 carbon atoms, together with alkoxides having from 1 to 5 carbon atoms, comprises carrying out the reaction solvent-free using a phase-transfer catalyst. In this method, the contents of the fatty acid ester should be from 85 to 99.9% by weight, those of the alkoxide component from 0.05 to 10% by weight, and those of the phase-transfer catalyst from 0.05 to 5.0% by weight, in each case based on the total reaction mixture. Esters of linoleic acid and linolenic acid are preferred as starting material, just as sodium or potassium methoxide or sodium or potassium ethoxide are preferred as alkoxide. Suitable phase-transfer catalysts are, for example, polyethylene glycols, polyethylene glycol monomethyl ethers or polyethylene glycol dimethyl ethers, crown ethers and quaternary ammonium or phosphonium salts. Using this method, which is preferably carried out in a two-phase system at pressures between 1.0 and 2.0 bar and method temperatures of from 60 to 150° C., products can be obtained in which at least 90% of the theoretically isomerizable double bonds are present in conjugated form. The claimed method is used in particular for producing conjugated linoleic acid methyl esters or linoleic acid ethyl esters and is distinguished, in particular, by an extremely simple and economic procedure.

Dependencies are inferred from the claim text.