Characterization of insoluble material isolated from Colombian palm oil biodiesel

Palm oil biodiesel (POB) is characterized by a very high precipitate content. Precipitate has caused potential customers to view POB unfavorably, thereby putting the suitability of this biofuel at risk. Therefore, precipitates isolated from POB were characterized in this study. The precipitates were fractionated by column chromatography, and then characterized using thin layer chromatography, FTIR, GC-FID, differential scanning calorimetry, and thermogravimetric analysis. Characterization revealed the preponderant presence of monopalmitin and free steryl glucosides (FSG) in the precipitates. FTIR suggested the presence of acylated steryl glucosides and fatty acid soaps, and thermal analysis revealed the presence of trace contaminants that may have coeluted with the monopalmitin and FSG during fractionation. All these findings should result in the development of techniques to prevent precipitate formation not only focused on the removal of FSG from POB.