Kinetic studies on oil extraction and biodiesel production from underutilized Annona squamosa seeds

The present investigation involves the production of biodiesel from non-edible Annona squamosa oil. Oil extraction has been done using aqueous HCl, H2SO4, and H3PO4 solutions with hexane at various temperatures. The optimum acid concentration is 20 wt.% H2SO4 containing hexane with the maximum oil yield of 28.5%. The reaction order has been found to be first-order kinetics and the activation energy is 44.054 kJ mol (1). Solid acid catalyst prepared by impregnation with phosphoric acid has proved to be an efficient catalyst for the transesterification process. An optimum conversion of 85% has been achieved at 65 degrees C; methanol-oil molar ratio 18: 1; 5 wt.% catalyst. The conversion of triglycerides into methyl esters obeys the first-order mechanism and Ea = 9.042 kJ mol (1). Physico-chemical characteristics have been determined as per American Oil Chemists Society (AOCS) methods and the fuel properties complied the limits prescribed in the ASTM D6751 standards. (C) 2016 Elsevier Ltd. All rights reserved.