论文部分内容阅读
采用量子化学的QCISD(T)/6-311+G(d,p)//BHandHLYP/6-311G(d,p)方法研究了氟代甲烷CH4-nFn(n=1~3)与CH3自由基氢抽提反应的微观动力学性质.并利用Polyrate程序分别计算了3个反应在200~3000K范围内的速率常数.计算结果表明,R1a,R2a和R3三个反应路径的反应能量分别为-12.7,-9.5和11.8kJ/mol,相应的能垒依次为67.0,62.2和67.5kJ/mol.在437K时,kCVT/SCT分别为6.72×10-19,8.01×10-18和8.82×10-20cm3/(molecule.s).计算结果还表明,在低温段反应的量子隧道效应显著,在计算温度范围内变分效应对反应速率常数的影响可以忽略.
The results show that the CH 4 -nFn (n = 1 ~ 3) and CH 3 free (CH 3) n The hydrogenation reaction was carried out by the Polyrate program and the rate constants of three reactions were calculated in the range of 200-3000 K. The calculated results show that the reaction energies of the three reaction paths R1a, R2a and R3 are - 12.7, -9.5 and 11.8 kJ / mol, respectively, and the corresponding energy barriers were 67.0, 62.2 and 67.5 kJ / mol, respectively.The kCVT / SCT at 437K were 6.72 × 10-19, 8.01 × 10-18 and 8.82 × 10- 20cm3 / (molecule.s). The calculated results also show that the quantum tunneling effect is significant at low temperature, and the effect of the variational effect on the reaction rate constant can be neglected within the calculated temperature range.