Transesterification of rapeseed oil with methanol in the presence of various co-solvents

Abstract

In this study, transesterification of rapeseed oil using various co-solvents(diethyl ether (DEE), dibutyl ether (diBE), tert-butyl methyl ether (tBME), diisopropyl ether (diIPE), tetrahydrofuran (THF), and acetone) was studied. The variables affecting the ester yield during transesterification reaction, such as catalyst content, methanol:oil molar ratio, methanol:cosolvent molar ratio, co-solvent type, catalysts type, agitation rate and reaction temperature were investigated. The process was monitored by gas chromatography, determining the concentration of the methyl esters. Biodiesel was characterized according to ISO norms. Among the studied co-solvents, the DEE and tBME take to the best results, however diIPE, diBE and acetone hardly improve the obtained results using only methanol. Within the range of studied variability, the rest of variables do not exercise a very significant influence. The best results are obtained with 0.7 % of KOH, a molar ratio methanol/oil of 9:1, a molar ratio co-solvent/methanol 1:1, an agitation rate of 700 rpm and a temperature of 30 ºC