Zhang Dan, Zhang Renyi
Department of Atmospheric Sciences, Texas A&M University, College Station, 77843, USA.
J Chem Phys. 2005 Mar 15;122(11):114308. doi: 10.1063/1.1862616.
A combined quantum-chemical and RRKM/ME (ME--master equation) approach is employed to investigate the structures, energetics, and kinetics of intermediate and stable species, and the yields of stabilized carbonyl oxides and OH radicals from the alpha-pinene and beta-pinene ozonolysis reactions. The cycloaddition of O(3) is highly exothermic, with the reaction energies of 55.1 and 51.1 kcal mol(-1) for alpha- and beta-pinenes, respectively. Cleavage of primary ozonides yields carbonyl oxides with the barrier height of 12.2-17.5 kcal mol(-1). For the prompt reactions of carbonyl oxides from alpha- and beta-pinene ozonolysis, H migration to hydroperoxides represents the dominant pathway over ring closure to dioxiranes. The kinetic calculations indicate a significant portion of stabilization for alpha- and beta-carbonyl oxides. The yields of stabilized carbonyl oxides are estimated to be 0.34 for alpha-pinene and 0.22 for beta-pinene. The applicability of theoretical methods for investigation of oxidation reactions of large hydrocarbon molecules is demonstrated.
采用量子化学与RRKM/ME（ME——主方程）相结合的方法，研究了α-蒎烯和β-蒎烯臭氧分解反应中中间体和稳定物种的结构、能量学和动力学，以及稳定化羰基氧化物和OH自由基的产率。O(3)的环加成反应是高度放热的，α-蒎烯和β-蒎烯的反应能量分别为55.1和51.1 kcal mol(-1)。初级臭氧化物的裂解产生羰基氧化物，势垒高度为12.2 - 17.5 kcal mol(-1)。对于α-蒎烯和β-蒎烯臭氧分解产生的羰基氧化物的快速反应，氢迁移至氢过氧化物是比环化生成二氧杂环丙烷更主要的途径。动力学计算表明，α-和β-羰基氧化物有很大一部分会发生稳定化。稳定化羰基氧化物的产率估计α-蒎烯为0.34，β-蒎烯为0.22。证明了理论方法在研究大型烃类分子氧化反应中的适用性。
