Degradation of unsaturated triglycerides injected into a pressurized reactor

To evaluate the precombustion chemistry of vegetable oils under conditions that exist in a diesel engine, several pure unsaturated triglycerides (triolein, trilinolein, trilinolenin) were injected into a pressurized reactor where they were subjected to thermal and oxidative degradation under varying conditions of atmosphere (air or nitrogen), temperature and pressure. Vapor samples were collected and then analyzed by gas chromatography/mass spectrometry techniques. In general, the samples consisted of similar mixtures regardless of the reaction conditions or triglyceride used as starting material. The most prominent compounds identified in these samples were fatty acids of different chain lengths and a variety of aliphatic hydrocarbons. Smaller numbers of other classes of compounds, such as aldehydes, were also detected.