TY - JOUR AB - Recycled vegetable oil (RVO) is a relatively cheap raw material for biodiesel production, but biodiesel grade methyl ester yields from RVO were found to be considerably lower than those from pure plant oil. The present paper investigates sources of yield loss during methanolysis of RVOs with free fatty acids (FFA) contents of 0.4-3.3%, and makes suggestions for the improvement of methyl ester yields. Data presented here indicated that yield losses of methyl esters during methanolysis were due to triglyceride and methyl ester hydrolysis and to the dissolution of methyl esters in the glycerol phase. Hydrolysis of triglycerides and methyl esters seemed to be the only side reaction causing yield losses, and the amount of fatty acids from hydrolysis increased with concentration of the potassium hydroxide catalyst. Dissolution of methyl esters in the glycerol phase was probably caused by the detergent effect of potassium salts of fatty acids originating from FFA in the RVO and from triglyceride hydrolysis, and the amount of dissolved methyl esters increased with FFA content of the RVO. The FFA content of the RVO had no effect on hydrolysis, and the amount of triglycerides and methyl esters hydrolysed during methanolysis remained constant with increasing FFA content of the RVO. AD - TEAGASC, Crops Res Ctr, Carlow, Poland AN - WOS:000265966500009 AU - Frohlich, A. AU - Rice, B. DA - Mar DO - 10.1007/s11746-008-1344-5 IS - 3 J2 - J Am Oil Chem Soc KW - recycled vegetable oil LA - English N1 - 444fq PY - 2009 SN - 0003-021x SP - 269-275 ST - Sources of Methyl Ester Yield Reduction in Methanolysis of Recycled Vegetable Oil T2 - Journal of the American Oil Chemists Society TI - Sources of Methyl Ester Yield Reduction in Methanolysis of Recycled Vegetable Oil UR - ://WOS:000265966500009 VL - 86 ID - 18320 ER -