Biodiesel production from crude palm oil and evaluation of butanol extraction and fuel properties

Three principal variables, molar ratio of methanol to oil, amount of catalyst, and reaction temperature, affecting the yield of acid-catalyzed production of methyl ester (biodiesel) from crude palm oil were investigated. The biodiesel was then used as an extractant in batch and continuous acetone-butanol-ethanol fermentation, and its fuel properties and that of the biodiesel-ABE product mix extracted from the batch culture analyzed. The optimized variables, 40:1 methanol/oil (mol/mol) with 5% H2SO4 (vol/wt) reacted at 95 degreesC for 9 h, gave a maximum ester yield of 97%. Biodiesel preferentially extracted butanol, and enhanced its production in the batch culture from 10 to 12 g l(-1). The fuel properties of biodiesel and the biodiesel-ABE mix were comparable to that of No.2 diesel, but their cetane numbers and the boiling points of the 90% fractions were higher. Therefore, they could serve as efficient No. 2 diesel substitutes, The biodiesel-ABE mixture had the highest cetane number. (C) 2001 Elsevier Science Ltd. All rights reserved.