Organic reactions in emulsions—Preparation of glycerol and polyglycerol esters of fatty acids by transesterification reaction

Abstract Monoglycerol and polyglycerol esters of fatty acids have been prepared in an emulsion medium of polyglycerol in esters of fatty acids. Transesterification between glycerol or polyglycerols and methyl esters of fatty acids is made at relatively low temperatures (95–150 C) in the presence of alkaline catalyst and anionic or nonionic emulsifiers. The reaction system consists of two immiscible phases transformed into a “milky” (macro) or transparent (micro) emulsion throughout the heating process. The product obtained using this technology is not a highly substituted ester since the transesterification reaction is selective. The type and the amount of emulsifier have to be carefully selected. Unsuitable emulsifiers which will not stabilize the emulsion are ineffective in enlarging the contact between the reactants; therefore, the conversion of the reactants is very poor. With suitable emulsifiers, the conversions and the yields improved due to a better contact between reactants.