Characterization of wax esters, free fatty alcohols and free fatty acids of crude wax from sunflower seed oil refineries

The sunflower seed wax (10-12%) from oil refineries was purified through two steps, namely, extraction using solvents and precipitation with chilled acetone. Fatty esters, free fatty alcohols and free fatty acids were separated by thin-layer chromatography (TLC). The fractions of fatty esters and free fatty alcohols were separated and identified by gas chromatography (GC) using a Dexil-300 column and OV-101 column, respectively, at temperatures from 150-290 degrees C and were further confirmed by Gas chromatography-mass spectrometry (GC-MS), using a capillary silica column SPB (TM)-1 coated with polydimethyl siloxane. Among the long chain fatty esters (C-38-C-54), comprised of one unit of fatty alcohol and one unit of fatty acid through an ester linkage, the major esters were C-40-C-44. of which C-42 was predominant. These fatty esters, upon hydrolysis, followed by methylation and subsequent GC-MS analysis, showed the presence of C-16-C-30 fatty acids in the bound form, whereas methylation of native wax indicated the presence of C-18-C-30 fatty acids in the free form. Acetylation of hydrolysis product showed the presence Of C18-C30 fatty alcohols in the bound form, where as acetylation of native wax indicated that the C-18-C-32 fatty alcohols were in the free form. n-Triacontanol (C-30), a plant growth regulator, was found in both free and bound forms. (c) 2006 Elsevier Ltd. All rights reserved.