A Search for Alternative Solvent To Hexane During Neem Oil Extraction

The growing environmental concerns on the toxicity and flammability of hexane motivate the need to obtain a more environmentally friendly solvent capable of extracting as much oil as hexane or even more, while giving acceptable oil quality. This study therefore investigated the possibility of replacing Hexane with either Ethanol or the mixtures of both in the extraction of Neem Oil from Neem seed. It was observed that as the extraction time increased, oil yield increased, though there was little or no increase in oil yield at 5hours and 6 hours of operations. At different extraction time, Hexane produced oil yields greater than that obtained from Ethanol. Hence, Ethanol did not prove to be a good replacement for Hexane, even at higher temperature of 750C for Ethanol. Optimum temperature of extraction was found to be 550C. Surprisingly, mixtures of Ethanol and Hexane gave commendable results. Particularly, Ethanol-Hexane mixtures of 60/40, 50/50, and 40/60 % (volume proportions) gave better oil yields of 44%, 43% and 41.2% respectively than that of Hexane (40.25%) at the 6 hours of operation, thereby making the combinations good substitutes for Hexane.