International Journal of Advanced Research in Chemical Science (IJARCS) Volume 6, Issue 10, 2019, PP 22-27 ISSN No. (Online) 2349-0403 DOI: http://dx.doi.org/10.20431/2349-0403.0610003 www.arcjournals.org International Journal of Advanced Research in Chemical Science (IJARCS) Page | 22 The Initiated Formation of Ethylene Glycol from Methanol– Formaldehyde Solutions Michael M. Silaev Chemistry Faculty, Moscow State University, Moscow 119991, Russia 1. INTRODUCTION Ethylene glycol is widely used in the production of polyester fibers and films, antifreezes, hydraulic and quench liquids, alkyds, polyurethanes, etc. The main commercial method of ethylene glycol synthesis is ethylene oxide hydration. The annual world ethylene glycol output is over 20 million tons. These facts stimulate development of new, energetically efficient ethylene glycol synthesis technologies. A possible one is radiation-chemical synthesis using a dual-purpose heterogeneous nuclear reactor in which the graphite moderator is replaced with a methanol –formaldehyde mixture and the heat carrier is steam flowing past fuel elements. A technological analysis of this system demonstrated that, at a reactor thermal power of 2.5 GW, it is possible to profitably manufacture 80 thousand tons of ethylene glycol per year along with producing 677 MW electric power. Here, we report the experimental dependences of the radiation-chemical yield of ethylene glycol on the total formaldehyde concentration at different temperatures and present the reaction network deduced for the process examined. By applying quasi-steady-state treatment to this network, we obtain a rate equation for ethylene glycol formation. 2. EXPERIMENTAL The experimental procedure used in this study, including the gas chromatographic analysis of stable products, was described in our earlier publication [1]. The concentration x of the free formaldehyde species in a methanol solution was determined by high-temperature UV spectrophotometry in the range 375–391 K at the total formaldehyde concentration c 0 (free and bound species including the concentration of polymer solvates) of 1.0–7.0 mol dm –3 .The 60 Со γ-radiation dose rate was 6.9 Gys –1 , as determined with a ferrous sulfate dosimeter. The dose absorbed by the solution with the electron density of methanol taken into account was (1.25–6.28) ×10 4 Gy. The total relative error of the experiment was ≤10%. The rate equations were derived by quasi-steady-state treatment, which is most suitable for describing the processes including at least eight to ten reactions with four to six different free radicals and at Abstract: The mechanism and kinetics are developed for the initiated nonbranched-chain formation of ethylene glycol in methanol–formaldehyde solutions at formaldehyde concentrations of 0.1–3.1 mol dm –3 and temperatures of 373–473 K. The experimental concentrations of the free unsolvated form of formaldehyde are given at the different temperatures and total concentrations of formaldehyde in methanol. The experimental dependence of the radiation-chemical yields of ethylene glycol on formaldehyde concentration in γ-radiolysis of methanol–formaldehyde solutions at 373–473 K is shown. At a formaldehyde concentration of 1.4 mol dm –3 and T = 473 K, the radiation-chemical yield of ethylene glycol is 139 molecules per 100 eV. The effective activation energy of ethylene glycol formation is 25 ± 3 kJ mol –1 . The quasi-steady-state treatment of the reaction network suggested here led to a rate equation accounting for the non-monotonic dependence of the ethylene glycol formation rate on the concentration of the free (unsolvated) form of dissolved formaldehyde. It is demonstrated that the peak in this dependence is due to the competition between methanol and CH 2 =O for reacting with the adduct radical HOCH 2 CH 2 O • . Keywords: Methanol, Formaldehyde, Formation, Ethylene Glycol, Radiation-Chemical Yield, Rate Equation. *Corresponding Author: Michael M. Silaev, Chemistry Faculty, Moscow State University, Moscow 119991, Russia