Physicochemical Properties of Rubber (Hevea brasiliensis) Seed Oil, Its Biodiesel and Blends with Diesel

Literature search shows that research on feed stocks for the production of biodiesel in Africa have not been well documented. To close this gap, a research project was initiated to measure the fuel and physicochemical properties of common vegetable oils in Nigeria. The works on cashew nut oil has been reported and that of rubber seed oil is being reported in this paper. Rubber tree seed oil has several industrial applications but not all the fuel and physicochemical properties are available in literature, hence the aim of this study is to provide the properties of not only the oil but also the biodiesel, 20% and 10% blends with diesel. For the purpose of characterization, the oil was extracted by soxhlet extraction and the free fatty acids was measured and found to be 23.68 % which can react with the sodium hydroxide catalyst to form soaps that can inhibit the separation of the esters and glycerin. To prevent this, acid catalyst was first used to neutralize and reduce the high level of free fatty acids in the oil to less than 2% before using sodium hydroxide for the transesterification process. The resulting biodiesel was washed, dried and blended 20% and 10% with diesel. The fatty acid profiles were determined by chromatography analyzer and the oil was found to be unsaturated. The characterization of the oil, its biodiesel, and the blends were done according to ASTM and EU methods and the results obtained show that the properties of the biodiesel and blends are similar to those of diesel which shows conclusively that it can be used as alternative fuel for diesel engines.