Best of biodiesel: Transesterification from vegetable oil

From vegetable oil to high-tech fuel: Transesterification
Source material for biodiesel is usually derived from widely available vegetable oils, depending on region:palm oil, coconut in tropical regions, soybean in the USA, rapeseed(canola) in northern Europe.

Vegetable oils - just as an animal fats - are made from triglycerides, i.e. the combination of trivalent alcohol glycerol with three fatty acids. Their molecular structure precludes their use for conventional combustion diesel engines in their pure form. The key is to replace the trivalent glycerol with a monovalent methanol: this transforms the thick vegetable oil into a biodiesel with excellent flow characteristics. And all it takes is a simple chemical reaction: transesterification with methanol and a small quantity of an alkaline catalyst, Sodium methylate solution in methanol and Potassium methylate solution in methanol have become the industry's preffered choice. The state of vegetable oil determines the efficacy and cost efficiency of these catalyst. To prevent undesired side effects, such as soaping or increase catalyst requirement, the crude oil should be purified to water content of max. 0.3% or a free fatty acid content of max. 1%. In addition to biodiesel, transesterification also yields glycerol as a valuable by-product for pharmaceutical and cosmetics industry.