The transesterification reactions were carried out in a 250 ml 3-necked round bottomed flask. The middle neck was used to insert a mechanical stirrer (BioLab BL 232 D), one of the side necks was fitted with a water-cooled condenser, and the other neck was fitted with a temperature indicator. The speed of the mechanical stirrer was monitored by using an analog tachometer (Fuji Kogyo Co. Ltd., Kyoto). The desired amount of catalysts, methanol and waste frying oil was introduced into the round bottomed flask and the reactions were carried out at 65 °C for 1 h. After the reaction is completed, the catalyst was separated by filtration and the transesterification products were allowed to settle overnight for the clear separation of biodiesel and glycerol. The conversion of oil to fatty acid methyl esters was analyzed by 1H Nuclear Magnetic Resonance Spectroscopy (1H NMR) using a Bruker Avance III 500 MHz (AV 500) spectrometer. CDCl3 was used as solvent. An equation has been given by Knothe [12] to calculate the percentage conversion of methyl esters