Kinetics of amidation of free fatty acids in jatropha oil as a prerequisite for biodiesel production

- It is a comprehensive study on amidation of FFA present in jatropha oil using monoethanolamine.
- Fatty acid amide obtained as by-product was established by with analytical tools such as IR, 1H NMR and ESI-MS.
- Optimization of amidation process parameters.
- Development of a kinetic model for amidation of FFA Present in jatropha oil.

Owing to the growing demand for transportation fuel, enormous efforts are being carried on development of alternate fuels mainly biodiesel from various renewable sources. Different pretreatment methods are adopted for the preparation of biodiesel, major one of the them is the removal of free fatty acids (FFA). Literature reveals esterification as an essential unit process for the reduction of FFA by conversion into its respective esters. In this study, FFA present in jatropha oil were reduced by amidation reaction using monoethanolamine for use in biodiesel. The by-product obtained is fatty acid amide. The fatty acid amide obtained was separated from the feedstock by filtration or centrifugation. This pre-treated oil can be directly transesterified for the preparation of biodiesel without undergoing any process step for removal of unreacted amine. Also, the reaction kinetics of jatropha oil with monoethanolamine was studied with batch experiments at 34-64 °C and at molar ratios of FFA-monoethanolamine varying from 1:0.5 to 1:2 with different speeds of agitation. Based on the experimental results, 1:1.5 FFA-monoethanolamine molar ratio at 34 °C and 550 rpm gave maximum reduction in free fatty acids. The effect of reaction conditions such as temperature and molar ratio on the kinetics has been studied. Observed reaction rate data was fitted to the regression technique. Estimated kinetic model reaction rate constants and equilibrium constant were fitted to the Arrhenius and van't Hoff equations respectively. The deacidified jatropha oil was transesterified by conventional method and was characterized for its physico-chemical properties.

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