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首页> 外文学位 >Oxidation of dimethyl-ether and ethylene in the atmosphere and combustion environment and thermodynamic studies on hydrofluorocarbons usingab initio calculation methods.
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Oxidation of dimethyl-ether and ethylene in the atmosphere and combustion environment and thermodynamic studies on hydrofluorocarbons usingab initio calculation methods.

机译：使用从头算方法在大气和燃烧环境中对二甲醚和乙烯进行氧化，并对氢氟烃进行热力学研究。

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摘要

Reaction pathways and kinetics are analyzed on CH3OC .H2 unimolecular decay and on the complete CH3OC .H2 + O2 reaction system using thermodynamic properties DH&j0;f 298,S&j0; 298, and Cp(T) 300 ≤ T/K ≤ 1500) derived by two ab initio calculation methods, CBS-q and G2. These are used to determine thermodynamic properties of reactants, intermediate radicals and transition state (TS) compounds. Quantum Rice-Ramsperger-Kassel (QRRK) analysis is used to calculate energy dependent rate constants, k(E), and master equation is used to account for collisional stabilization. Comparison of calculated fall-off with experiment indicates that the CBS-q and G2 calculated Ea,rxn for the rate controlling transition state (beta-scission reaction to CH 2O + C.H2OOH) needs to be lowered by factor of 3.3 kcal/mol and 4.0 kcal/mol respectively in order to match the data of Sehested et al. Experimental results on dimethyl-ether pyrolysis and oxidation reaction systems are compared with a detailed reaction mechanism model. The computer code CHEMKIN II is used for numerical integration. Overall agreement of the model data with experimental data is very good.;Reaction pathways are analyzed and kinetics are determined on formation and reactions of the adduct resulting from OH addition to ethylene using the above ab initio methods. Hydrogen atom tunneling is included by use of Eckart formalism. Rate constants are compared with experimentally determined product branching ratios (C.H2CH 2OH stabilization: CH2O + CH3 : CH3CHO + H).;ab initio calculations are performed to estimate thermodynamic properties of nine fluorinated ethane compounds (fluoroethane to hexafluoroethane), eight fluoropropane (1-fluoropropane, 1,1- and 1,2-difluoropropane, 1,1,1- and 1,1,2-trifluoropropane, 1,1,1,2- and 1,1,2,2-tetrafluoropropane and 1,1,1,2,2-pentafluoropropane), and 2-fluoro,2-methylpropane. Standard entropies and heat capacities are calculated using the rigid-rotor-harmonic-oscillator approximation with direct integration over energy levels of the intramolecular rotation potential energy curve. Enthalpies of formation are estimated using G2MP2 total energies and isodesmic reactions. Thermodynamic properties for fluorinated carbon groups C/C/F/H2, C/C/F2/H, C/C/F3, C/C2/F/H, C/C2/F2 and C/C3/F for fluorinated alkane compounds, CD/F/H and CD/F2 for fluorinated alkene compounds and CT/F for fluorinated alkyne compounds are estimated. Fluorine-fluorine interaction terms F/F, 2F/F, 3F/F, 2F/2F, 3F/2F and 3F/3F for alkane compounds, F//F, 2F//F and 2F/2F for alkene compounds, and F///F for alkyne compound are also estimated.
机译：利用热力学性质DH＆j0; f 298，S＆j0;对CH3OC.H2单分子衰变和整个CH3OC.H2 + O2反应系统的反应途径和动力学进行了分析。 298和Cp（T）300≤T / K≤1500）通过两种从头算计算方法CBS-q和G2得出。这些用于确定反应物，中间自由基和过渡态（TS）化合物的热力学性质。量子莱斯-拉姆斯珀格-卡塞尔（QRRK）分析用于计算能量依赖的速率常数k（E），主方程式用于解决碰撞稳定问题。计算出的衰减量与实验值的比较表明，对于速率控制过渡态（对CH 2O + C.H2OOH的β-分裂反应），需要将CBS-q和G2计算出的Ea，rxn降低3.3 kcal / mol。为了匹配Sehested等人的数据，分别为4.0kcal / mol和4.0kcal / mol。将二甲醚热解和氧化反应体系的实验结果与详细的反应机理模型进行了比较。计算机代码CHEMKIN II用于数值积分。该模型数据与实验数据的总体一致性非常好。；使用上述从头算方法，分析了反应路径并确定了由OH加成至乙烯所产生的加合物的形成和反应的动力学。使用Eckart形式主义包括氢原子隧穿。将速率常数与实验确定的产物支化比（C.H2CH 2OH稳定度：CH2O + CH3：CH3CHO + H）进行比较;从头算来估算九种氟化乙烷化合物（氟乙烷与六氟乙烷），八种氟丙烷（ 1-氟丙烷，1,1-和1,2-二氟丙烷，1,1,1-和1,1,2-三氟丙烷，1,1,1,2-和1,1,2,2-四氟丙烷和1 （1,1,2,2-五氟丙烷）和2-氟，2-甲基丙烷。使用在分子内旋转势能曲线的能级上直接积分的刚性-转子-谐波-振荡器近似来计算标准熵和热容。利用G2MP2的总能量和等电势反应估算形成焓。氟代烃C / C / F / H2，C / C / F2 / H，C / C / F3，C / C2 / F / H，C / C2 / F2和C / C3 / F的热力学性质估算了氟代烯烃化合物的CD / F / H和CD / F2以及氟代炔烃化合物的CT / F。对于烷烃化合物，氟-氟相互作用项为F / F，2F / F，3F / F，2F / 2F，3F / 2F和3F / 3F，对于烯烃化合物为F // F，2F // F和2F / 2F，以及还估计了炔烃化合物的F /// F。

著录项

  • 作者

    Yamada, Takahiro.;

  • 作者单位

    New Jersey Institute of Technology.;

  • 授予单位 New Jersey Institute of Technology.;
  • 学科 Chemistry Organic.;Physics Atmospheric Science.;Environmental Sciences.;Chemistry Physical.
  • 学位 Ph.D.
  • 年度 1999
  • 页码 274 p.
  • 总页数 274
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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