The influence of vegetable oils composition on separation of transesterification products, especially quality of glycerol

Abstract

The paper describes the properties of glycerol produced by transesterification, especially the ester content in the glycerol phase (ester losses) including the distribution of esters according to higher fatty acids. Glycerol, produced by transesterification of oil as a side product – the polar glycerol phase, is an important chemical raw material. The decreasing of ester losses is important because it (i) increases the ester yield and especially (ii) decreases the cost of glycerol purification. The transesterification of oils (rapeseed, olive, palm, sunflower and Camelina Sativa) with various distributions of fatty acids was carried out by methanol, ethanol and butanol including different transesterification stopping. The losses of ethyl and butyl esters are much higher than losses of methyl ester (approximately 2–3x). The distribution of ethyl and butyl esters in the glycerol phase is the same as in the ester phase, whereas distribution of methyl ester is different and depends on the way of transesterification stopping. The reason is the different polarity of methyl esters, which depends on the type of fatty acid. The polarity increases with increasing of double bonds, i.e. the most soluble is methyl ester of linolenic acid in the glycerol phase.