Thesis (M.Eng.)--Chulalongkorn University, 2011

Biolubricants derived from vegetable oils and fatty acids are environmentally compatible products due to their low toxicity and good biodegradability. In this work, biolubricant production by an esterification reaction of oleic acid and propanol was studied, where immobilized Novozym 435 lipase enzyme was used as a biocatalyst. The experiments were carried out in a shaking incubator to investigate effect of reaction time, alcohol structure (propanol vs. isopropanol), enzyme loading, rotation speed, molar ratio of propanol to oleic acid, and reaction temperature. The optimal condition were 45oC, molar ratio of PrOH to Oleic acid of 2:1, Novozym 435 loading at 5% based on oleic acid weight and 250 rpm, in which the maximal FFA conversion at 88.9% was obtained. It was shown that the FFA conversion could be increased to 94.7% (or 6.5% increases) by removal of water during the reaction using molecular sieve. From kinetic study, the activation energy of the esterification reaction was 34.05 kJ/mol. Finally, it demonstrated that Novozym 435 could be used at least 5 cycles without considerable change in the conversion for propyloleate production.