Abstract
Improving the antioxidant and antiwear properties of alternative ethanol-based motor fuels is a pressing problem in petrochemistry. The most rational way to solve this problem is currently considered to be the addition of metal complex compounds in small concentrations to the composition of such fuels. Copper(II) chelates with fluorinated 1,3-diketones, hexafluoroacetylacetone, etc., due to their high volatility and stability, are used in many application areas. However, the use of copper(II) chelate with hexafluoroacetylacetone as an additive to high-tonnage petroleum products (motor fuels and oils) is hindered by the high price of fluorinated 1,3-diketones. The use of fluorinated 1,3-ketoaldehydes, trifluoroacetylacetaldehyde, etc. can solve this problem and increase the stability of such copper(II) chelates. A series of copper(II) chelates with fluorine-containing ligands of different structures was synthesized, their structure and influence on the chemical properties of alternative ethanol-containing motor fuels were investigated. The antioxidant activity of copper(II) chelates was determined by the volumetric method (gasometric setup) on a model reaction of initiated radical-chain oxidation of benzyl alcohol (thermal initiator – 2,2΄-azo-bis-isobutyronitrile, free radical generation rate Wi = 2.98 10–8 М·s–1, temperature – 50±0.2 °C, partial oxygen pressure – 0.02-0.1 MPa). The dependence of the antiwear properties of ethanol solutions on the concentration of copper(II) chelates was evaluated by the change in the bearing capacity (dynamic strength) of the solution according to the ASTM D2783 method on a four-ball tribometer at the critical load value. It was established that the synthesized fluorine-containing copper(II) chelates are inhibitors of the catalytic action of chain breakage in the oxidation of benzyl alcohol, which leads to a long-term inhibition of its oxidation process. The fact of a significant (by 40-65 %) increase in the antiwear properties of ethanol solutions when copper(II) chelates are introduced into their composition in low concentrations of 0.001-0.01 wt. % was revealed. The prospects of using ultra-low concentrations of synthesized metal complexes for improving the chemical properties of alcohol-containing motor fuels were shown.
References
Ковтун Г.А., Плужников В.А. Химия ингибиторов окисления органических соединений. – Наук. думка, Киев, 1995. – 284 с..
Joshi K.S., Pathak V.N. Metal Chelates of Fluorinated 1,3-Diketones and Related Compounds. Coord. Chem. Rev., 1977, 22, 31–122.
Belford R. Linn, Martell A.E., Calvin M. Influence of fluorine substitution on the properties of metal chelate compounds. I Copper(II) chelates of bidentate ligands. J. Inorganic and Nuclear Chemistry, 1956, 2, 11–31.
Gerus I.I., Gorbunova M.G., Kukhar V.P. β-Ethoxyvinyl polyfluoroalkyl ketones - versatile synthones in fluoroorganic chemistry. J. Fluorine Chem., 1994, 69, 195–198.
Hojo M., Masuda R., Kokuryo Y., Shiods M., Matsuo S. Electrophilic substitutions of olefinic hydrogens ii. acylation of vinyl ethers and n-vinyl amides. Chem. Lett., 1976, 5, 499–502.
Dolomanov O.V., Bourhis L.J., Gildea R.J., Howard J.A.K., Puschmann H. OLEX2: a complete structure solution, refinement and analysis program. J. Appl. Crystallogr. 2009, 42, 339–341.
Sheldrick G.M. SHELXT – Integrated space-group and crystal-structure determination. Acta Crystallogr. Sect. A Found. Adv. 2015, 71, 3–8.
Sheldrick G.M. Crystal Structure Refinement with SHELXL. Acta Crystallogr. Sect. C, 2015, 71, 3–8.
Gerus I.I., Balabon O.A., Pazenok S.V., Lui N., Kondratov I.S., Tarasenko K.V., Shaitanova E.N., Ivasyshyn V.E., Kukhar V.P. Synthesis and Properties of Polyfunctional Cyclic-Alkoxy-α, Unsaturated Ketones Based on 4-Methylene-1,3-dioxolanes. Eur. J. Org. Chem., 2018, 27–28, 3853–3861. 10.1002/ejoc.201800786.
Ковтун Г.А., Каменева Т.М., Нестеров Д.С., Кокозей В.Н. Гетерополиядерный комплекс [CuCoCd((L)2(H2L)2(NCS)Br2]·CH3OH в катализе обрыва цепей окисления спиртов. Доп. НАН України, 2006, 8, 168–171.
Yadav G., Tiwari S., Jain M.L. Tribological analysis of extreme pressure and anti-wear properties of engine lubricating oil using four ball tester. Materials Today: Proceedings, 2018, 5(1), 248–253.
Ковтун Г.А., Моисеев И.И. Металлокомплексные ингибиторы окисления. – Наук. думка, Киев, 1993. – 224 с.
Бойченко С.В. Раціональне використання вуглеводневих палив. – НАУ, Київ, 2001. – 216 с.
Hadley J.W. A method for the evaluation of the boundary lubricating properties of aviation turbine fuels. Wear, 1985, 101, 219–253.
Hsieh P.Y., Bruno T.J. A perspective on the origin of lubricity in petroleum distillate motor fuels. Fuel Processing Technology, 2015, 129, 52–60.