Calcium glyceroxide promoted esterification of oleic acid with glycerol and its mathematical modelling

Abstract

The classical methods of esterification of long-chain fatty acids with glycerol are conducted under extreme conditions (homogeneous acid catalyst, high temperature). Therefore, the development of new catalytic processes for obtaining glycerides of higher carboxylic acids is an important task. This paper presents experimental kinetic data and mathematical modeling of the esterification of oleic acid with glycerol using calcium glyceroxide as a catalyst. The results of comparing the catalytic activity of calcium glyceroxide with calcium oleate are presented. The results showed that the compared catalytic systems have different effects on the reaction progress. It was found that the esterification catalyzed by calcium glyceroxide proceeds with an induction period. However, after 10 hours of synthesis, the difference in conversion exceeds 15% in favor of calcium glyceroxide. The influence of various factors on the induction period of the oleic acid esterification process with glycerol was established. It was shown that the initial autocatalysis of the reaction occurs due to the formation of a surfactant in the reaction mixture – oleic acid monoglyceride, which is confirmed by changes in the viscosity of the reaction mass during the esterification process. A mathematical model of fatty acid esterification with glycerol catalyzed by calcium glyceroxide was developed. The reliability of the approximation R² for the correlation of experimental and calculated concentrations of oleic acid was approximately ∼0.99. The developed mathematical model reflects the essential properties of the modeled process and can be used for further technological reactor design calculations.