Glycerine Esterification with Free Fatty Acids: Homogeneous Catalysis

MAIRA MAQUIRRIARIN; CARLOS QUERINI; MARIA LAURA PISARELLO

CHEMICAL ENGINEERING RESEARCH & DESIGN

INST CHEMICAL ENGINEERS

Año: 2021 vol. 171 p. 86 - 99

0263-8762

tThe esterification of glycerine with free fatty acids using sulfuric, p-toluenesulfonic, andmethanesulfonic acids as catalysts is studied in detail analyzing the effect of different vari-ables. These catalysts resulted to be much more active than the heterogeneous catalysts,which require very high temperatures in order to convert high fractions of free fatty acids.The differences in activities among these homogeneous catalysts are explained based ontheir surface tensions.This parameter plays a key role in the kinetic behavior, affecting the interface area. Aninductive period in the reaction was observed and explained on the basis of the surfacetension changes that occur during the reaction due to the formation of monoglycerides,which are compounds that decrease the interfacial tension.In this reacting system there is a formation of important amount of secondary productswith a darkening of the reaction media. In this work these products have been quantifiedunder different reaction conditions, showing the best way of conducting this reaction inorder to minimize this loss of yield. Using methanesulfonic acid at a low concentration of0.35 equiv/L and low temperature (100◦C) complete conversion is obtained with a yield of95% without darkening of the product.