Thesis (M.Sc.)--Chulalongkorn University, 2012

The research aimed to improve the cold flow property of biodiesel from neem oil (NME) by using 14 types of synthesized pour point depressants (PPDs) which were isopropyl ester (IPE), 2-butyl ester (BE), methyl laurate (ML), methyl palmitate (MP), methyl oleate (MO), methyl linoleate (MLi), isopropyl laurate (IPL), isopropyl palmitate (IPP), isopropyl oleate (IPO), isopropyl linoleate (IPLi), 2-butyl laurate (BL), 2-butyl palmitate (BP), 2-butyl oleate (BO), and 2-butyl linoleate (BLi). All of these PPDs were synthesized by esterification reaction and characterized by Nuclear magnetic resonance spectroscopy (1H NMR). The results indicated that cloud point (CP) and pour point (PP) of biodiesel from neem oil (NME) could be decreased in the range of 1.0±1.0 °C to 7.0±1.0 °C and from 1.0±1.0 °C to 6.0±1.0 °C, respectively. BL gave the best result on improving cold flow property of biodiesel due to the steric hindrance of branched chain alcohol. At 300,000 ppm of BL, cloud point (CP) and pour point (PP) of NME were decreased from 15.0±1.0 °C to 8.0±1.0 °C and from 10.0±1.0 °C to 4.0±1.0 °C, respectively.