Acid-catalysed Fischer esterification of fatty acids with methanol as a reagent and solvent is regularly used to prepare long chain alkyl methyl esters. Transesterification of palm oil in basic media using methanol is also a synthesis route to prepare methyl esters of fatty acids. In this work, we report a Fischer esterification in methanol of a sample of local palm oil sludge (rich in fatty acids) where a column chromatography fraction analysed by gas chromatography-mass spectrometry matched an unexpected mixture of ethyl esters of oleic and palmitic acids, probably as result of a transesterification reaction that occurred during the extraction step using ethyl acetate in basic media.
