Analysis of optimal conditions for biodiesel production from Jatropha oil in supercritical methanol: Quantification of thermal decomposition degree and analysis of FAMEs

•Non-edible Jatropha oil to produce biodiesel in supercritical methanol.•Maximum FAME yield of 99.5 wt% is obtained at 325 °C, 90 min and 42:1 methanol/oil.•Thermal decomposition is evidenced at the temperature of 350 °C.•The maximum thermal cracking degree (24.16%) is obtained at 350 °C and 90 min.•The individual FAMEs thermally degraded are oleic and linoleic.

Recent years have seen great efforts made to optimise the production of biodiesel as an alternative to fossil fuel. This study looks at the optimal conditions for producing second generation biodiesel in supercritical methanol from Jatropha oil. Triglyceride conversion and the yield of monoglycerides, diglycerides and fatty acid methyl esters (FAMEs) are analysed for different ranges of temperature and time. The maximum conversion of triglycerides (100 wt%) and maximum yield of FAMEs (99.5 mol%) were achieved at 325 °C with a reaction time of 90 min. The thermal decomposition of the biodiesel produced was greatest (24.16%) at 350 °C and 90 min. Quantification of individual methyl esters showed that the fatty acid chains affected by temperature were those of oleic and linoleic acids. Finally, a lineal regression model was applied to predict the effect of temperature on the biodiesel produced.

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