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用密度泛函理论B3LYP方法对煤炭燃烧过程中N2O的消除反应进行研究。选用6-311++G**和aug-cc-pVTZ基组,优化了反应通道上反应物、过渡态和产物的几何构型。预测了它们的热力学性质(总能量、焓、熵和吉布斯自由能)及其随温度的变化。预测N2O+CO反应的活化能为200kJ·mol-1,与实验值193±8kJ·mol-1较一致。计算了500~1800K温度范围的反应速率常数。在N2O的分解中,N2O与H和CN自由基的反应为动力学优先进行的反应,其活化能为50~55kJ·mol-1。在B3LYP/aug-cc-pVTZ level水平下,N2O+CN反应是热力学最有利的自发反应,其吉布斯自由能变化为-407kJ·mol-1。
The B3LYP method of density functional theory was used to study the elimination reaction of N2O in coal combustion. The 6-311 ++ G ** and aug-cc-pVTZ basis sets were chosen to optimize the geometry of reactants, transition states and products on the reaction channels. Their thermodynamic properties (total energy, enthalpy, entropy and Gibbs free energy) and their changes with temperature are predicted. The activation energy of N2O + CO reaction is predicted to be 200 kJ · mol-1, which is consistent with the experimental value of 193 ± 8 kJ · mol-1. The reaction rate constant in the temperature range of 500 ~ 1800K was calculated. In the decomposition of N2O, the reaction of N2O with H and CN radicals is a kinetically preferred reaction with an activation energy of 50-55 kJ · mol-1. At B3LYP / aug-cc-pVTZ level, the N 2 O + CN reaction is the thermodynamically most favorable spontaneous reaction with a Gibbs free energy change of -407 kJ · mol -1.