Optimization of Biodiesel Production from Sunflower Oil Using Central Composite Design
The current study investigated the effect of catalyst ratio and methanol to oil ratio on biodiesel production by using central composite design. Biodiesel was produced by transesterification using sodium hydroxide as a homogeneous catalyst, a laboratory scale reactor consisting of flat bottom flask mounts with a reflux condenser and a heating plate was used to produce biodiesel. Key parameters, including, time, temperature and mixing rate were kept constant at 60 minutes, 60 oC and 600 RPM, respectively. From the results obtained, it was observed that the biodiesel yield depends on catalyst ratio and methanol to oil ratio. The highest yield of 50.65% was obtained at catalyst ratio of 0.5 wt.% and methanol to oil mole ratio 10.5. The analysis of variances of biodiesel yield showed the R Squared value of 0.8387. A quadratic mathematical model was developed to predict the biodiesel yield in the specified parameters ranges.
 Marchetti, J. M., Miguel, V. U. & Errazu, A. F., 2007. Possible methods for biodiesel production. Renewable and Sustainable Energy Reviews, 11(6), pp.1300–1311.
 Leung, D. Y. C., Wu, X. & Leung, M. K. H., 2010. A review on biodiesel production using catalyzed transesterification. Applied Energy, pp. 1083–1095.
 Atabani, A. E., Silitonga, A. S., Ong, H. C., Mahlia, T. M. I., Masjuki, H. H., Badruddin, I. A. and Fayaz, H. (2013) ‘Non-edible vegetable oils: A critical evaluation of oil extraction, fatty acid compositions, biodiesel production, characteristics, engine performance and emissions production’, Renewable and Sustainable Energy Reviews. Elsevier, 18, pp.
 Pourzolfaghar, H., Abnisa, F., Mohd, W. and Wan, A. (2016) ‘A review of the enzymatic hydroesteri fi cation process for biodiesel production’, Renewable and Sustainable Energy Reviews. Elsevier, 61, pp. 245–257.
 Yusoff, M., Brask, J., Munk, P. and Guo, Z. (2016) ‘Journal of Molecular Catalysis B: Enzymatic Kinetic model of biodiesel production catalyzed by free liquid lipase from Thermomyces lanuginosus’, ‘Journal of Molecular Catalysis. B, Enzymatic’. Elsevier B.V., 133, pp. 55–64.
 Ediger, V. Ş., Akar, S. and Uǧurlu, B. (2006) ‘Forecasting production of fossil fuel sources in Turkey using a comparative regression and ARIMA model’, Energy Policy, 34(18), pp. 3836–3846.
 Ilmi, M., Hommes, A., Winkelmana, J. G. M., Hidayatc, C. and Heeres, H. J. (2017) ‘Enzymatic biodiesel synthesis using novel process intensification principles’, Biochemical Engineering Journal, 114, pp. 110–118.
 Demirbas, A. (2009) ‘Biofuels securing the planet’s future energy needs’, Energy Conversion and Management. Elsevier Ltd, 50(9), pp. 2239–2249.
 Chouhan, A. P. S. and Sarma, A. K. (2011) ‘Modern heterogeneous catalysts for biodiesel production: A comprehensive review’, Renewable and Sustainable Energy Reviews. Elsevier Ltd, 15(9), pp. 4378–4399.
 Cheng, G., Meng, X. & Wang, Y., 2008. Biodiesel production from wasre cooking oil via alkali catalyst and its engine test., Beijing, China: s. n.
 Lukovi, N., Kneževi, Z. & Bezbradica, D., 2009. Biodiesel Fuel Production by Enzymatic Transesterification of Oils: Recent Trends, Challenges and Future Perspectives, Alternative Fuel, Dr. Maximino Manzanera (Ed.), ISBN: 978-953-307-372-9, InTech, Available from: http://www.intechopen.com/books/alternative-fuel/biodiesel-fuel-production-by-enzymatic-transesterification-of-oils.htm (accessed 12.08.2016).
 Sani, Y. M., Daud, W. M. A. and Abdul Aziz, A. R. (2012) ‘Biodiesel Feedstock and Production Technologies: Succes.
 Kim, H. J. et al., 2004. Transesterification of vegetable oil to biodiesel using heterogeneous base catalyst. Catalysis Today, 93–95, pp.315–320.
 Patil, P. D. and Deng, S. (2009) ‘Optimization of biodiesel production from edible and non-edible vegetable oils’, Fuel. Elsevier Ltd, 88(7), pp.
 Uriarte, F. A. J. (2010) Biofuels from Plant Oils. Jakarta: ASEAN Foundation.
 Romano, S. D., Sorichetti, P. A. and Energy, G. (2011) ‘Introduction to Biodiesel Production’.
 Zhang, L., Sheng, B., Xin, Z., Liu, Q. and Sun, S. (2010) ‘Kinetics of transesterification of palm oil and dimethyl carbonate for biodiesel production at the catalysis of heterogeneous base catalyst’, Bioresource Technology. Elsevier Ltd, 101(21), pp. 8144–8150.
 Thinnakorn, K. and Tscheikuna, J. (2014) ‘Biodiesel production via transesterification of palm olein using sodium phosphate as a heterogeneous catalyst’, Applied Catalysis A: General. Elsevier B.V., 476, pp. 26–33.
 Amoah, J., Ho, S. H., Hama, S., Yoshida, A., Nakanishi, A., Hasunuma, T., Ogino, C. and Kondo, A. (2016) ‘Lipase cocktail for efficient conversion of oils containing phospholipids to biodiesel’, Bioresource Technology. Elsevier Ltd, 211(April), pp. 224–230.
 Al-zuhair, S., Wei, F. and Song, L. (2007) ‘Proposed kinetic mechanism of the production of biodiesel from palm oil using lipase’, Process Biochemistry, 42, pp. 951–960.
 Lam, M.K., Lee, K.T. & Mohamed, A.R., 2010. Homogeneous, heterogeneous and enzymatic catalysis for transesterification of high free fatty acid oil (waste cooking oil) to biodiesel: A review. Biotechnology Advances, 28(4), pp.500–518.
 Samir Najem Aldeen Khurshid (2014) ‘Biodiesel Production by Using Heterogeneous Catalysts’, Royal Institute of Technology, (March), pp. 1–63.
 Silitonga, A. S. et al., 2014. Biodiesel conversion from high FFA crude jatropha curcas, calophyllum inophyllum and ceiba pentandra oil. Energy Procedia, Volume 61, pp. 480-483.
 Shahidi, F., 2005. Bailey"s Industrial Oil and Fats. Sixth Edition ed. s. l.: John Waily and Sons.
 Autino, H., Wnuk, F. & Vacca, P., 1993. Aceites Grasas. Volume 3, p. 21–30.
 Montgomery, D. C., 2005. Design and Analysis of Experiments: Response surface method and designs. New Jersey: John Wiley and Sons, Inc.1302–1306.
 Meher, L. C., Vidya Sagar, D. & Naik, S. N., 2006. Technical aspects of biodiesel production by transesterification - A review. Renewable and Sustainable Energy Reviews, 10(3), pp.248–268.
 Lin, L., Ying, D., Chaitep, S. & Vittayapadung, S., 2009. Biodiesel production from crude rice bran oil and properties as fuel. Applied Energy, 86, pp. 681-688.