Chemical Extraction and Property Analyses of Marula Nut Oil for Biodiesel Production
ABSTRACT
To identify and develop alternative and renewable sources of fuel for the transport sector is a present challenge for engineers and researchers. This work was carried out to assess yield of marula (Sclero carrya/birrea) nut and chemical properties of crude marula nut oil for biodiesel production in Botswana. Chemical extraction of marula oil was done to establish actual oil content by use of hexane / iso-propyl alcohol solvent in a soxhlet set up. Distillation was carried out on a Rotavapor system prior to oil purging using nitrogen gas. The results indicated that marula nuts have about 58.6% oil content. Characterisation of the extracted crude oil was carried out to determine its chemical composition using the Waters GCT Premier Time of Flight (TOF) Mass Spectrometer (MS) coupled to the Agilent 6890N Gas Chromatography (GC) system. Ethyl oleate (ethyl ester) was found to be the dominant fatty acid. Trans-Oleic acid was also abundant but could not be quantified because it was not found in the standard mixture. Crude marula oil was also found to have an ester content of 93.7%, acid value of 1.4mgKOH/g, and free fatty acid content of 0.7%. These results are marginally out of specifications for biodiesel by international standards, implying that crude marula oil is a potential substrate for biodiesel production.
To identify and develop alternative and renewable sources of fuel for the transport sector is a present challenge for engineers and researchers. This work was carried out to assess yield of marula (Sclero carrya/birrea) nut and chemical properties of crude marula nut oil for biodiesel production in Botswana. Chemical extraction of marula oil was done to establish actual oil content by use of hexane / iso-propyl alcohol solvent in a soxhlet set up. Distillation was carried out on a Rotavapor system prior to oil purging using nitrogen gas. The results indicated that marula nuts have about 58.6% oil content. Characterisation of the extracted crude oil was carried out to determine its chemical composition using the Waters GCT Premier Time of Flight (TOF) Mass Spectrometer (MS) coupled to the Agilent 6890N Gas Chromatography (GC) system. Ethyl oleate (ethyl ester) was found to be the dominant fatty acid. Trans-Oleic acid was also abundant but could not be quantified because it was not found in the standard mixture. Crude marula oil was also found to have an ester content of 93.7%, acid value of 1.4mgKOH/g, and free fatty acid content of 0.7%. These results are marginally out of specifications for biodiesel by international standards, implying that crude marula oil is a potential substrate for biodiesel production.
Cite this paper
nullJ. Gandure and C. Ketlogetswe, "Chemical Extraction and Property Analyses of Marula Nut Oil for Biodiesel Production," Advances in Chemical Engineering and Science, Vol. 1 No. 3, 2011, pp. 96-101. doi: 10.4236/aces.2011.13016.
nullJ. Gandure and C. Ketlogetswe, "Chemical Extraction and Property Analyses of Marula Nut Oil for Biodiesel Production," Advances in Chemical Engineering and Science, Vol. 1 No. 3, 2011, pp. 96-101. doi: 10.4236/aces.2011.13016.
References
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[1] M. S. Graboski, R. L. McCormick, “Combustion of Fat and Vegetable Oil Derived Fuels in Diesel Engines,” Progress in Energy and Combustion Science, Vol. 24, 1998, pp. 125-164. doi:10.1016/S0360-1285(97)00034-8 [2] P. M. Adriano, C. T. Richard, M. Luciano, C. Jonas and F. A. Dejanira, “Biodegradability of Diesel and Biodiesel Blends,” African Journal of Biotechnology, Vol. 7, No. 9, 2008, pp. 1323-1328. [3] C. Shu-Mei, H. Yuh-Jeen, C. Shunn-Cheng, Y. Hsi-Hsien, “Effects of Biodiesel Blending on Particulate and Poly-cyclic Aromatic Hydrocarbon Emissions in Nano/Ul- trafine/Fine/Coarse Ranges from Diesel Engine,” Aerosol and Air Quality Research, Vol. 9, No. 1, 2009, pp. 18-31. [4] M. J. Haas, A. J. McAloon, W. C. Yee, T. A. Foglia, “A Process Model to Estimate Biodiesel Production Costs,” Bioresource Technology, Vol. 97, 2006, pp. 671-678. doi:10.1016/j.biortech.2005.03.039 [5] J. D. MacFarlane, “Determining Total Acid in Biodiese,” 2011.www.LaboratoryEquipment.com. [6] W. Kyamuhangire, “Perspective of Bioenergy and Jatro-pha in Uganda,” International Consultation on Pro-Poor Jatropha Development, Casa Son Bernadu, via Lawren-tina, Rome, Vol. 289, 2008. [7] Committee for Standardization, “European Standards for Biodiesel,” 2010. www.EN14214.com.