Synergistic Effect of Mixed Methanol/Ethanol on Transesterification of Waste Food Oil Using p-Toluenesulfonic Acid as Catalyst

In this study, pensive waste food oil was used as raw material, the p-toluenesiilfonic acid as catalyst; the nzethanoli ethanol as a transesterification agent to m-q-)are hiodiesel was reported. The results indicated that the mixed methanol ethano' contributed to improving the biodiesel perjbrmance. Specifically when mole percentage of ethanol in the total alcohol was 30%, the yield reached 99. 59%, and heating value reached 40.47 11/ Kg. /1 was higher than that of single methanol and single ethanol as transesterification agent, respectively. The concentration of saturated fatty acid esters iii the biodiesel were also increased by mixed methanol/zethanol as transesterification agent (i.e. increase in the proportion of H in C/P1); resulting ill higher biodiesel heating value. The 'mixed methanol ethanol also showed a good synergistic effect iii the biodiesel preparation process. The solubility of ethanol iii oil is superior to that in methanol, and ethanol plots a double role of the cosolvent and the transesterification agent. Methanol weakened the drawbacks of the steric effect and emulsification efject of ethanol. This study showed that the methanol can be partially substituted by ethanol. It reduced not only the dependence on methanol, but also the yield and healing value biodiesel can be increased. (C) 2015 American Institute Chemical Engineers Environ Prog, 34: 1547-1553, 2015