Keywords
biodiesel
potassium butoxide
oxidation stability
antioxidant
How to Cite
Abstract
Current paper deals with production, purification and oxidative stability enhancement of fuel-grade sunflower oil butyl esters as more ecological alternative of methyl esters as biodiesel. The oil feedstock, used in this study, included refined sunflower oil (acid value – 0.05 mg KOH/g; 25.3 % of oleic and 61.2 % of linoleic acids) and wasted frying high-oleic sunflower oil (acid value – 1.20 mg KOH/g; 6.1 % of linoleic and 81.7 % of oleic acids). Butanolysis was carried out using potassium butoxide, obtained from KOH and alcohols via original patent-pending method, under mild reaction conditions (alcohol-to-oil molar ratio – 4.5-5.0, 15°C, 1.4-1.6 %еq. KOH of butoxide, 20-30 min). High molar yield of butyl esters (93-96 %) was achieved, while glycerol and vast majority of alkaline catalyst formed the separate reaction products phase mainly in the course of reaction. Ester enriched phases were purified in order to obtain fuel-grade butanol-based biodiesel. Samples after removing of butanol under vacuum followed by water washing and drying were characterized by not enough high butyl esters content (about 94-95 %), as well as higher than allowed content of unconverted glycerides. Vacuum distillation as final purification step allowed fitting butyl esters samples composition within the requirements for biodiesel fuel. Distilled samples contained about 99 % of butyl esters, 0.4-0.5 % of monoglycerides and almost no n-butanol, glycerol, di- and triglycerides. Oxidative treatment (110°C, 6 h, air bubbling) revealed the high oxidation stability of the sample, originated from wasted high-oleic oil, due to the predominance of oleic acid in its fatty acid composition. The sample, obtained from refined sunflower oil (mainly linoleic acid in fatty acid composition), demonstrated very low stability. Addition of at least 2000 mg/kg of antioxidant 2,6-di-tert-butyl-4-methylphenol was shown to be able to improve this characteristic to the level of biodiesel requirements.
References
The Biodiesel Handbook, 2nd edn. (G. Knothe, J. Krahl, J. van Gerpen). Elsevier, Urbana, Illinois. 2010. 482.
Advances in Biodiesel Production. (R. Luque, J. Melero). Woodhead Publishing, Cambridge. 2012. 304.
Fonseca J.M., Teleken J.G., Almeida V.C., Silva C. Biodiesel from waste frying oils: Methods of production and purification. Energ. Conv. Manage. 2019. 184. 205-218.
Bouaid A., El Boulifi N., Hahati K., Martinez M., Aracil J. Biodiesel production from biobutanol. Improvement of cold flow. Chem. Eng. J. 2014. 238. 234-241.
Trypolska G.S, Podolets R.Z. The biofuels market in Ukraine. Economy and forecasting. 2017. N2. 75-92. [in Ukainian]
Konovalov S., Patrylak L., Zubenko S., Okhrimenko M., Yakovenko A., Levterov A., Avramenko A. Alkali synthesis of fatty acid butyl and ethyl esters and comparative bench motor testing of blended fuels on their basis. Chem. Chem. Technol. 2021. 15. 105-117.
Patrylak L.K., Zubenko S.O., Konovalov S.V., Povazhnyi V.A. Alkaline transesterification of sunflower oil triglycerides by butanol-1 over potassium hydroxide and alkoxides catalysts. Issues of chemistry and chemical technology, 2019. 5. 93-103.
Hájek M., Skopal F., Vávra A., Kocík J. Transesterification of rapeseed oil by butanol and separation of butyl ester. J. Clean. Prod. 2017. 155. 28-33.
Musil M., Skopal F., Hajek M., Varva A. Butanolysis: Comparison of potassium hydroxide and potassium tertpd-butoxide as catalyst for biodiesel preparing from rapeseed oil. J. Environ. Manage. 2017. 218. 28-33.
Homan T., Shahbaz K., Farid M. M. Improving the production of propyl and butyl ester-based biodiesel by purification using deep eutectic solvents. Sep. Purif. Technol. 2017. 174. 570-576.
Patent UA108271. Zubenko S.O., Okhrimenko M.V., Patrylak L.K., Voloshyna Yu.G., Yakovenko A.V., Konovalov S.V., Sushko N.M. The method of the catalyst preparing for biodiesel production. 2016. [In Ukrainian]
Yaakob Z., Narayanan B.N., Padikkaparambil S., Unni S.K., Akbar M.P. A review on the oxidation stability of biodiesel. Renew. Sust. Energ. Rev. 2014. 35. 136-153.
Yamane K., Kawasaki K., Sone K., Hara T., Prakoso T. Oxidation stability of biodiesel and its effect on diesel combustion and emission characteristics. J. Engine Res. 2007. 8. 307-19.
Dunn Robert O. Effect of temperature on the oil stability index (OSI) of biodiesel. Energy Fuels. 2008. 22. 657-62.
Kim. J.-K., Jeon Ch.-H., Lee H.W., Park Y.-K., Min K., Hwang I., Kim Y.M. Effect of Accelerated High Temperature on Oxidation and Polymerization of Biodiesel from Vegetable Oils. Energies. 2018. 11. 3514.
Nwafor O.M.I. The effect elevated fuel inlet temperature on performance of diesel engine running on neat vegetable oil at constant speed conditions. Renew. Energy. 2003. 28. 171-181.
Chuck C.J., Bannister C.D., Jenkins R.W., Lowe J.P., Davidson M.G., A comparison of analytical techniques and the products formed during the decomposition of biodiesel under accelerated conditions. Fuel. 2012. 96. 426-433.
McCormick R.L. Westbrook S.R. Storage stability of biodiesel and biodiesel blends. Energy Fuels. 2010. 24. 690-698.
Choe E., Min D.B. Mechanisms and factors for edible oil oxidation. Compr. Rev. Food Sci. Food Saf. 2006. 5. 169-186.
Russell G.A. Deterium-isotope effects in the autoxidation of aralkyl hydrocarbons. Mechanism of the interaction of Peroxy radicals. J. Am. Chem. Soc. 1957. 79. 3871-3877.
Wojdyło A, Oszmian ́ski J, Czemerys R. Antioxidant activity and phenolic compounds in 32 selected herbs. Food Chem. 2007. 105. 940-949.
Tang H, Wang A, Salley S, Ng KYS. The effect of natural and synthetic antioxidants on the oxidative stability of biodiesel. J. Am. Oil. Chem. Soc. 2008. 85. 373-82.
Patent UA123473. Zubenko S.O., Konovalov S.V., Patrylak L.K. The method of the catalyst preparing for fatty acid esters production. 2021. [In Ukrainian].
McCurry J.D., Wang Ch.-X. Analysis of Glycerin and Glycerides in Biodiesel (B100) Using ASTM D6584 and EN14105. Agilent Technologies. 2007.
Zubenko S.O. The simple method of vegetable oils and oleochemical products acid value determination. Catalysis and Petrochemistry. 2021. N31. 69-71.
Thoaia D.N., Tonguraia Ch., Prasertsita K., Kumar A. A novel two-step transesterification process catalyzed by homogeneous base catalyst in the first step and heterogeneous acid catalyst in the second step. Fuel Proc. Technol. 2017. 168. 97-104.
Pradhan S., Shen J., Emami S. et al. Synthesis of potassium glyceroxide catalyst for sustainable green fuel (biodiesel) production. J. Ind. Eng. Chem. 2017. 46. 266–272.
Ruiz-Méndez M.V., Marmesat S., Liotta A., Dobarganes M.C. Analysis of used frying fats for the production of biodiesel. GRASAS ACEITES. 2008. 59. 45–50.
Vieitez I., Callejas N., Irigaray B., Pinchak Y., Merlinski N., Jachmanian I. Grompone M. Acid Value, Polar Compounds and Polymers as Determinants of the Efficient Conversion of Waste Frying Oils to Biodiesel. J. Am. Oil Chem. Soc. 2014. 91. 655–664.
Demurin Y., Scoric D., Karlovic D. Genetic variability of tocopherol composition in sunflower seeds as a basis of breading for improved oil quality. Plant Breed. 1996. 115. 33-36.
Aladedunye F., Przybylski R. Frying stability of high oleic sunflower oils as affected by composition of tocopherol isomers and linoleic acid content. Food Chem. 2013. 141. 2373-2378.
Pighinelli A.L.M.T., Ferrari A.R., Miguel A.M.R.O, Park K.J. High oleic sunflower biodiesel: quality control and different purification methods. Grasas Aceites. 2011. 62. 171-180.
Jakeria M.R., Fazal M.A., Haseeb A.S.M.A. Influence of different factors on the stability of biodiesel: A review. Renew. Sust. Energ. Rev. 2014. 30. 154-163.
Pullen J., Saeed K. An overview of biodiesel oxidation stability. Renew. Sust. Energ. Rev. 2012. 16. 5924-5950.
Zubenko S.O., Okhrimenko M.V., Kyrpach K.O., Konovalov S.V., Patrylak L.K. Degradation of ethyl and butyl fatty acids esters obtained from rapeseed and linseed oils during protracted storage and ways of its prevention. XXХІ Scientific conference on bioorganic chemistry and petrochemistry of the Institute of bioorganic chemistry and petrochemistry of the NAS of Ukraine (Kyiv, March 31 – April 1, 2016) Catalysis and petrochemisty. 2016. N25. 95.