Thesis (M.Sc.)--Chulalongkorn University, 2015

This research aims to synthesize pour point depressants from three types of dicarboxylic acids including 1,4-cyclohexanedicarboxylic acid, isophthalic acid and terephthalic acid by esterification using five types of alcohols including 1-propanol, 2-propanol, 1-butanol, 2-butanol and 2-methyl-1-propanol to improve flow properties at low temperature of palm biodiesel. These synthetic pour point depressants were characterized by proton nuclear magnetic resonance spectroscopy technique. The flow properties at low temperature of palm biodiesel were tested according to ASTM D 2500 and ASTM D 97 by adding pour point depressants at 10,000, 50,000, 100,000, 150,000 and 200,000 ppm. The result indicated that di 2-butyl-terephthalate exhibited the best improvement of flow properties at low temperature of palm biodiesel. It can reduce cloud point value from 16.5 °C to 12.0 °C and pour point value from 11.5 °C to 3.0 °C at 200,000 ppm.