Biodiesel fuel synthesis by interesterification of triglycerides with carboxylate esters of low molecular weight

Abstract

Abstract The ever-increasing environmental pollution from greenhouse gases motivates the search for methods to reduce it. One such method is the use of biodiesel fuels in the transport sector. Conventional biodiesel production generates up to 10% of a by-product, raw glycerol, whose amount continues to increase as biodiesel production volumes expand, but its demand remains limited. Recently, options have been analysed to replace the triglyceride transesterification process generally used in biodiesel production with an interesterification process that does not generate raw glycerol, instead yielding triacylglycerol that can be directly used as fuel for diesel engines by mixing with fatty acid esters. Additionally, triacylglycerol improves the low-temperature properties of fuel. The present article discusses triglyceride interesterification processes using various carboxylate esters of low molecular weight. Information is provided on raw materials that can be subjected to interesterification for biodiesel synthesis. The possible applications of chemical and enzymatic catalysis for triglyceride interesterification are discussed, and the influence of the catalyst amount, molar ratio of reactants, temperature and process duration on the effectiveness of interesterification is examined. The conditions and effectiveness of noncatalytic interesterification are also discussed in the article. Qualitative indicators of the products obtained and their conformity to the requirements of the European standard for biodiesel fuel are discussed.