Catalytic Biodiesel Production Mediated by Amino Acid-Based Protic Salts.
Hetero- and homogeneous acid catalysts are effective catalysts for the production of biodiesel from oils containing high free fatty acids. The protic salts synthesized from natural amino acids were examined for catalytic activity and efficiency for the esterification of oleic acid after structural identification and characterization. In the esterification reaction of oleic acid with methanol, [Asp][NO3] was the best catalyst, and its high activity correlated to its high Hammett acidity. The optimal reaction conditions for the esterification of oleic acid to achieve 97 % biodiesel yield were: 70 °C, 10 % catalyst loading (w/w, on oleic acid basis), methanol/oleic acid ratio 7.5:1, and 5 h. Generally, [Asp][NO3] could be a good catalyst for the esterification of oleic acid with alcohols with chain lengths of up to six. The biodiesel yield of 93.86 % obtained from palm fatty acid distillate implies that the catalyst has potential for industrial application. A study of the kinetics indicated that the reaction followed pseudo-first-order kinetics with an activation energy and pre-exponential of 57.36 kJ mol-1and 44.24×105min-1, respectively. The aspartic acid-derived protic salt is a promising, operationally simply, sustainable, renewable, and possibly biodegradable catalyst for the conversion of free fatty acids into biodiesel.
Department of Engineering, Faculty of Science and Technology, Aarhus University, Gustav Wieds Vej 10, 8000, Aarhus C, Denmark.
Jingbo
0000-0001-5960-806X
J
Li
Department of Engineering, Faculty of Science and Technology, Aarhus University, Gustav Wieds Vej 10, 8000, Aarhus C, Denmark.
Zheng
0000-0002-8436-7082
Z
Guo
D000596:Amino Acids / Q000737:chemistry*; D056804:Biofuels; D066241:Carbon-13 Magnetic Resonance Spectroscopy; D002384:Catalysis; D004951:Esterification; D007700:Kinetics; D066244:Proton Magnetic Resonance Spectroscopy; D012492:Salts / Q000737:chemistry*; D013696:Temperature
D000596:Amino Acids; D056804:Biofuels; D012492:Salts
amino acids; biomass; fatty acids; homogeneous catalysis; waste prevention