Transesterification Of Pistacia Chinensis Seed Oil To Biodiesel Catalyzed By Immobilized Compound Lipase

Firstly, the influences of lipase, solvent, the molar ratio of substrates, the reaction temperature and time were optimized and the best result was obtained by transesterification from compound lipases (N435 and TLIM) at a concentration of 10% base on the oil weight, the molar ratio of methyl acetate to Pistacia Chinensis Seed Oil was 7, the molar ratio of Tert-butyl alcohol to oil was 20, the addition of organic base 3-hydroxymethyl-methane at a concentration of 10% base on the oil weight. The reaction mixture was stirred at 150 r·min-1 agitation speed with 45℃. In these conditions, after reaction 15 hours, the methyl ester yield was 54%.By orthogonal experiments on the reaction conditions are optimized to be suitable reaction conditions: 12% compound lipases base on the oil weight, the molar ratio of methyl acetate to Pistacia Chinensis Seed Oil was 7, the molar ratio of Tert-butyl alcohol to oil was 10, the addition of organic base 3-hydroxymethyl-methane at a concentration of 9% base on the oil weight, the reaction temperature was 45℃.The reaction mixture was stirred at 150 r·min-1 agitation speed. In these conditions, after reaction 15 hours, the methyl ester yield was 68.7%.Secondly, kinetics of compound lipase-catalyzed transesterification has been investigated. The reaction rate could be described in terms of the Michaelis-Menten equation with a Ping-Pong Bi-Bi mechanism and competitive inhibition by both the substrates. The values of the apparent kinetic parameters were computed as: Vmax =0.0359 mmol·( mL·min·g)-1, KA = 0.907 mol·L-1, KMA = 1.320 mol·L-1, KiA = 4.962 mol·L-1, KiMA = 1.432 mol·L-1. Compared with kinetics of single lipase, transesterification of Pistacia Chinensis Seed Oil to biodiesel catalyzed by immobilized compound lipase was better than single lipase.Finally, the products were tested by GC-MS and FT-IR: the main composition was methyl ester.