Ibrahima BALDE¹, Cheikhou KANE^1,, Abdou K.D. DIME², Samba BALDE³, Khady NDIAYE¹

Abstract This article is a contribution on vegetable oils epoxidation mechanisms understanding which is of great of interest in these last five years. Vegetable oils epoxidation mechanism is a chemical reaction that takes place at the double bonds. Most of the time, fats such as:myristic acid, palmitic acid, stearicacid, oleic acid, linoleic acid, alpha linoleic acid and arachidic acid are found in these oils. However, temperature, oxygen and light are among the factors that destroy oils. Two methods are used for the epoxidation of the later: - Prilezhaev epoxidation which consists in the in situ formation of an organic per acid such as performic acid or peraceticacid. The latter is obtained by the action of hydrogen peroxide on the carboxylic acid in the presence of sulfuric acid; -The use of enzymes is a process for the elimination of sulfuric and the decreasing of the amount of secondary reactions. The use of enzymes gives a better selectivity on soybean and linseed oils, for example, respectively 94 and 98% with an exceptional conversion rate higher than 98% and showing almost no side reactions in this enzymatic epoxidation process. However, if the pH is very low or the temperature is higher than 60°C, the formed epoxy rings can react with the peracid and open up intohydroxyl and acetoxy groups. In addition, solvents such as dimethylformamide as well as chlorinated solvents are increasingly being excluded in industry for environmental reasons. Epoxidation with hydrogen peroxide is less demanding in terms of pH, temperature and solvent use. Moreover, this epoxidation method is not subject to side reactions. The peak characteristics of the epoxy function by Fourier Transform Infrared is located around 822cm^-1.

vegetable oil, epoxidation, oxirane, environment