Utilization of crude karanj (Pongamia pinnata) oil as a potential feedstock for the synthesis of fatty acid methyl esters

Methyl esters were synthesized from crude karanj oil (CKO) by single step esterification with methanol using sulfuric acid (H2SO4) and phosphoric acid (H3PO4) as catalysts in a homogeneous batch process. H3PO4 was less active than H2SO4 during the process as it presented very low ester yields (<20%) for the various molar ratios of fatty acid to alcohol studied. With H2SO4 as catalyst, the yield was as high as 89.8% at 65 degrees C after 5 h. The fatty acids profile of the oil (palmitic acid: similar to 12%; stearic acid: similar to 8%; oleic acid: similar to 52% and linolenic acid of 17%) and the different reactivities of the acids were responsible for the observed differences in conversion to methyl esters. The findings attained with this study might contribute to the economic utilization of a non-edible feedstock. (C) 2012 Elsevier Ltd. All rights reserved.