Single step production of biodiesel from used cooking oil

Single stage production of biodiesel is achieved by the transesterification of used cooking oil. The presence of high free fatty acid (FFA) content showed insignificant effect on the transesterification reaction, and even the FFA was effectively converted into the methyl ester under basic medium. The reaction was done in a closed stainless steel reactor, where the solvothermal condition of methanol was achieved at the reaction temperature (65°C). The FAME (fatty acid methyl ester) content was more than 98% within 1.5 h of the reaction.