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碳前驱体热解机理的理论研究──反应能量、自由基的轨道能级及相对稳定性

王惠1,4; 翟高红1; 冉新权1; 史启祯1; 文振翼2; 罗瑞盈3; 杨延清4   

  1. 1.质西北大学化学系, 西安 710069; 2. 西北大学现代物理研究所, 西安 710069; 3. 北京航空航天大学, 北京 100083; 4. 西北工业大学材料科学系, 西安 710072
  • 收稿日期:2000-03-07 修回日期:2000-03-27 出版日期:2001-03-20 网络出版日期:2001-03-20

Quantum Chemistry Research of Pyrolysis Mechanism of Carbon Matrix Precursor─ Reaction energy change, orbital energy and relative stability

WANG Huil1,4; ZHAI GaD-Hong1; RAN Xin-Quan1; SHI Qi-Zhen1; WEN Zhen-Yi2; LUO Rui-Ying3; YANG Yan-Qing4   

  1. 1. Chemistry Department; Northwest University; Xi an 710069; China; 2. Institute of Modern Physics, Northwest University, Xi'an 710069, China; 3. Beijing University of Aeronautics and Astronautics, Beijing 100083, China, 4. Department of Material Science, Northwestern Polytechnic University, Xi'an 710072, China
  • Received:2000-03-07 Revised:2000-03-27 Published:2001-03-20 Online:2001-03-20

摘要: 运用Gaussian 98程序包中的 AM1方法,通过对间二甲苯系列化合物设定的8种热裂解过程的反应能量、生成自由基的轨道能级、自由基的相对稳定性的量子化学理论计算,研究了间二甲苯系列化合物的热反应活性及热裂解机理.计算结果表明:(1)各反应物的主反应路径均是苯环上甲基C-H键首先断裂.该结论与实验结果一致;(2)各反应物之间的热反应活性由大到小顺序为: COH(d)>CSH(d)>C10(a)> CCN(d).同时亦说明,自由基前线轨道能级差及生成自由基的相对稳定性和热力学等理论参数一样,亦适合于研究间二甲苯系列反应物的热解机理和热反应活性.

关键词: 碳前驱体, 热裂解机理, AM1法

Abstract: Standard enthalpy change, free energy change, entropy change, the frontier orbital energy and relative
stability of free radicals about the 8 types of design pyrolysis processes of the series of m-xylene compounds were calculated by the AM1 method in
Gaussian 98 program package. The results show that the pyrolysis process of these compounds first starts from the C--H bonds of the methyls on the
benzene rings. This conclusion is in accord with the experimental result. The activity sequence of the series of m-xylene compounds is
C8H9OH(d1)>C8H9SH(d2)>C8H10(a)>C8H9-CN(d3). At the same time, it is also proved that the frontier orbital energy difference
and the relative stability of these free radicals are the same as the thermodynamics parameters, so that they can be used to the study of the
pyrolysis mechanism and thermoreactive activity of this series of xylene compounds.

Key words: carbon matrix precursor, pyrolysis mechanism, AM1 method

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