Conjugation reaction of soybean oil with iodine as a catalyst

Abstract

A method for the iodine-catalyzed conjugation of soybean oil was developed, and the conjugated product was analyzed by UV, IR, and ¹H NMR. The results indicated that the optimal conditions for conjugation included a temperature of 180℃, a catalyst loading of 0.5 wt.% and a reaction time of 3 h, at which the concentration of conjugated linoleic acid was 1.51 mol L^-1, with 92 % conversion, the CLNA reached 0.225 mol L^-1 when the temperature was 130℃, a catalyst loading of 0.5 wt.%, and a reaction time of 3 h with a conversion rate of 99.9 %. The reaction predominantly produced trans-trans, trans-cis and cis-trans isomers. However, at the same temperature, much more trans-trans isomer was produced with the reaction time prolonged. It was also revealed that the conjugation of linolenic acid was much faster than that of linoleic acid. The method possessed the advantages of a short procedure, a high conversion rate, and no methyl esterification of the raw material, and it was an environmentally friendly technology that does not use solvents.