1,3-丁二烯-1-基（n-C4H5）氧化的机理和动力学：理论研究,Physical Chemistry Chemical Physics

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1,3-丁二烯-1-基（n-C4H5）氧化的机理和动力学：理论研究
Physical Chemistry Chemical Physics ( IF 2.9 ) Pub Date : 2021-4-3 , DOI: 10.1039/d1cp00567g
Denis P Porfiriev ₁ , Valeriy N Azyazov , Alexander M Mebel

Affiliation

从头算起，将C ₄ H ₅ O ₂势能面的CCSD（T）-F12 / cc-pVTZ-f12 // B3LYP / 6-311G（d，p）计算与Rice–Ramsperger–Kassel–Marcus Master结合使用通过方程式（RRKM-ME）计算与温度和压力有关的速率常数和产物支化比，以阐明n -C ₄ H ₅ + O ₂反应的机理和动力学。结果表明，该反应是快速的，总速率常数在3.4-5.6×10 ^-11 cm ³分子^-1 s ^-1范围内。主要产品包括1-oxo- n-丁二烯基+ O和丙烯醛+ HCO，在1500 K以上的温度下，它们的累积收率超过90％。通过将O ₂加到n的自由基位置上的简单机理形成了两个构型的1-oxo- n-丁二烯基+O 。-C ₄ ħ ₅随后通过O-O键程序的裂解通过范德华ç ₄ ħ ₅ ö⋯O复合。或者，导致丙烯醛+ HCO的途径涉及重原子骨架的显着重组，可通过一个O原子正式迁移到分子的另一端或插入C1-C2键。不计算初始过氧加合物的热稳定性（在低温和高压下普遍存在），所有其他产品的次要收率均低于5％。显着反应通道的速率常数已拟合到修正的Arrhenius表达式，并被提议用于芳香分子和1,3-丁二烯氧化的动力学模型。作为次级反应，n -C ₄ H ₅ + O ₂可能是丙烯醛在低燃烧温度下的氧化实验中观察到的形成丙烯醛的来源，而C ₆ H的另一个重要（次级）产物₁ +氧代正丁二烯基的单分子分解可形成₅ + O₂反应呋喃。两者Ñ -C₄ ħ₅ + O₂反应及其-1-氧代的单分子分解Ñ -butadienyl初级产物被示出不被烯酮的重要来源。

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Mechanism and kinetics of the oxidation of 1,3-butadien-1-yl (n-C4H5): a theoretical study

Ab initio CCSD(T)-F12/cc-pVTZ-f12//B3LYP/6-311G(d,p) calculations of the C₄H₅O₂ potential energy surface have been combined with Rice–Ramsperger–Kassel–Marcus Master Equation (RRKM-ME) calculations of temperature- and pressure-dependent rate constants and product branching ratios to unravel the mechanism and kinetics of the n-C₄H₅ + O₂ reaction. The results indicate that the reaction is fast, with the total rate constant being in the range of 3.4–5.6 × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹. The main products include 1-oxo-n-butadienyl + O and acrolein + HCO, with their cumulative yield exceeding 90% at temperatures above 1500 K. Two conformers of 1-oxo-n-butadienyl + O are formed via a simple mechanism of O₂ addition to the radical site of n-C₄H₅ followed by the cleavage of the O–O bond proceeding via a van der Waals C₄H₅O⋯O complex. Alternatively, the pathways leading to acrolein + HCO involve significant reorganization of the heavy-atom skeleton either via formal migration of one O atom to the opposite end of the molecule or its insertion into the C1–C2 bond. Not counting thermal stabilization of the initial peroxy adducts, which prevails at low temperatures and high pressures, all other products share a minor yield of under 5%. Rate constants for the significant reaction channels have been fitted to modified Arrhenius expressions and are proposed for kinetic modeling of the oxidation of aromatic molecules and 1,3-butadiene. As a secondary reaction, n-C₄H₅ + O₂ can be a source for the formation of acrolein observed experimentally in oxidation of the phenyl radical at low combustion temperatures, whereas another significant (secondary) product of the C₆H₅ + O₂ reaction, furan, could be formed through unimolecular decomposition of 1-oxo-n-butadienyl. Both the n-C₄H₅ + O₂ reaction and unimolecular decomposition of its 1-oxo-n-butadienyl primary product are shown not to be a substantial source of ketene.

更新日期：2021-04-13

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