To further understand the development of coal self-heating, the reaction sequences and thermal properties of aliphatic hydrocarbon groups during coal self-heating were analyzed. The structural parameters, frontier orbital characteristics, molecular orbital, and perturbation energy of aliphatic hydrocarbons and oxygen were analyzed by the quantum chemistry method. Then, the reaction pathways of aliphatic hydrocarbon groups and the corresponding reaction model were proposed. The results indicate that the reactions of aliphatic hydrocarbon groups include three kinds, i.e., the hydrogen capture by oxygen, reaction between aliphatic hydrocarbon radicals and the hydroxyl radical, and reaction between aliphatic hydrocarbon radicals and oxygen. The main reactions include the reaction between carbon free radicals and oxygen (E1), the reaction between aliphatic hydrocarbon and the hydroxyl radical (E2), the reaction between methyne and oxygen (E3), and other spontaneous reactions caused by E1 and E3 (E2). There is only one reaction procedure for the carbon free radical (R^•) to turn into peroxide (R–O–O^•) and cause more heat release. Reaction E3 generates less heat compared to reaction E1, but it can form hydroxyl radicals, which then result in other spontaneous reaction sequences (E2) to generate R^•, which will easily start reaction E1. Therefore, reaction sequence E3 includes two aspects of influence during coal reaction with oxygen, i.e., heat supply and the trigger of other further reactions. It shows that the reaction sequence of aliphatic hydrocarbon groups releases more heat than other reaction sequences and plays more important roles in the temperature rise process of coal self-heating. The results are useful for further exploring the reaction mechanism of spontaneous combustion of coal.

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煤自热过程中脂肪烃基的反应机理和热力学性质

为了进一步了解煤自热的发展过程，分析了煤自热过程中脂肪族烃基的反应顺序和热性质。用量子化学方法分析了脂肪族碳氢化合物和氧的结构参数，边界轨道特征，分子轨道和摄动能。然后，提出了脂族烃基的反应途径和相应的反应模型。结果表明，脂族烃基的反应包括三种：氧的氢捕获，脂族烃基与羟基的反应，脂族烃基与氧的反应。主要反应包括碳自由基和氧气（E1）之间的反应，脂肪烃和羟基自由基（E2）之间的反应，次炔与氧之间的反应（E3）以及E1和E3引起的其他自发反应（E2）。碳自由基（R^•）转化为过氧化物（R–O–O ^•）并引起更多的热量释放。与反应E1相比，反应E3产生的热量更少，但是它可以形成羟基自由基，然后导致其他自发反应序列（E2）产生R ^•，这很容易启动反应E1。因此，反应序列E3包括在煤与氧气反应期间的两个方面的影响，即供热和其他进一步反应的触发。结果表明，脂肪族烃基的反应顺序比其他反应顺序释放更多的热量，并且在煤自热的升温过程中起着更重要的作用。该结果对进一步探索煤的自燃反应机理是有用的。