Transesterification of triglycerides with ethyl acetate

Transesterification of triglycerides with ethyl acetate instead of methanol seems to be advantageous in respect to glycerin waste elimination. Sodium methanolate and metal sodium dispersion (0.4%) were used as a catalyst. The reaction occurred very quickly (5–30 min) at the temperature of 22–78 °C in a similar way as the common methanolysis but reached an equilibrium with a high content of acetylated monoglycerides (9–13%) and diglycerides (3–6%) in addition to fatty acid ethyl esters (72–81%) and glycerol acetates (4.5–6.2%). A similar product yield could be obtained while using 5% p-toluenesulfonic acid as a catalyst but after 40 h of reaction time. reactive distillation (RD) it was possible to evaporate the light volatile glycerol acetates and fatty acid ethyl esters and to shift the equilibrium towards the desired products. Reactive distillation was performed at the temperature of 200–230 °C by bubbling ethyl acetate vapor through rapeseed oil layer. Dodecylbenzene sulfonic acid (1%) was used as a catalyst. The product yield attained 8 g/h and was composed mainly of fatty acid ethyl esters (90%) and only little amounts of glycerol acetates. During the reaction a rapid decrease in catalyst activity was observed. The use of alkaline catalyst, like sodium methanolate, gave lower product yield of 2.6 g/h with higher content of glycerol acetates (7.7%) besides ethyl esters (90%). Using 2% zinc oxide as a catalyst contributed to obtaining only negligible yield of transesterification products (0.2 g/h).