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But to the best of our knowledge, there has not been comprehensively studied about the reaction between C 2H 3 and HO 2 which would have a big effect on the combustion of ethylene. 14 studied the kinetics of the allyl + HO 2 bimolecular reaction at the level of QCISD(T)/CBS//B3LYP/MG3S, which found that the reaction of allyl + HO 2 will promote chain branching significantly more than previous models suggest. 13 demonstrated that the induction period of propene ignition in the temperature range of 500–800 K is highly sensitive to allyl + HO 2 kinetics, and that omitting this reaction increased the induction period by an order of magnitude. 12 Similarly, allyl + HO 2 reaction also has been confirmed with of great effect on the combustion of propene. And the reaction CH 3 + HO 2 is among the most important reactions in methane ignition which is confirmed by Liu et al.
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11 studied that, in the modeling of CH 4/O 2, the CH 3 + HO 2 reaction was found to be an important source of OH during ignition which needed to be further studied. Similar to the reaction type of C 2H 3 + HO 2, Petersen et al. 7–10 Furthermore, R + HO 2 reactions can promote ignition by converting less reactive radicals into more reactive radicals OH. However, because of its high concentration in the low temperature preignition regime, even relatively slow reactions involving HO 2 can have a significant effect on the combustion process, especially in low-temperature combustion chemistry. At moderate temperature and high pressure, bimolecular reactions involving the hydroperoxyl radical (HO 2) and other radicals are critically important in ignition chemistry. 6 At high temperatures, alkyl radicals rapidly fragment to yield smaller radicals and a corresponding alkene. 1,2 And it is an important species in planetary atmospheres, 3–5 and hydrocarbon plasma chemistry.
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1 Introduction The vinyl radical (C 2H 3) has received increasing attention in recent years, since it is a key intermediate in combustion and pyrolysis of hydrocarbon fuels. It is shown that these parameters have improved the mechanism and that the simulation results for ethylene ignition in a shock tube are similar to the observed values. Finally, in order to investigate the effect of the calculated parameters on ignition delay, they were used to simulate ignition delay with the current mainstream mechanism. The calculated rate constants are in good agreement with limited data from the literature and are given in modified Arrhenius equation form, which are useful in combustion modeling of hydrocarbons. Thermochemical properties of the species involved in the reactions were determined using the QCISD(T)/CBS//M062X/6-311++G(d,p) method and enthalpies of formation of species were compared with literature values. The major product channel of the reaction C 2H 3 + HO 2 is the formation of C 2H 3O 2H via a highly vibrationally excited product. And Rice–Ramsberger–Kassel–Marcus/Master-Equation (RRKM/ME) theory was used to calculate the pressure-dependent rate constants of these channels. Conventional transition state theory (TST) was used to determine the rates where the reaction has a tight transition state variable reaction coordinate transition-state theory (VRC-TST) was used for rate constant calculations corresponding to the barrierless reactions.
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The potential energy surface (PES) for reaction of C 2H 3 + HO 2 was examined by using high-level quantum chemical methods.