摘要
臭氧层损耗是人类面临的重要环境问题之一。平流层中氟氯烃类化合物受紫外线光解所产生的氯代次甲基会消耗臭氧。为了弄清该自由基消耗臭氧的机制,用量子化学计算的方法详细地研究了CCI+O_3反应在二重态势能面上的反应机理。本文在B3LYP/6-311 G(d,p)水平上优化了反应物、中间体、过渡态和产物的几何构型,得到了相应的振动频率和能量值,并在相同水平上用内禀反应坐标计算方法确认了过渡态和中间体之间的联系,理清了该反应详细的路径。研究发现CCI+O_3反应有5种产物通道:CICO+O_2、CO_2+Cl+O、CO_2+CIO、CO+O_2+CI和OCO_2+Cl,通过对各反应路径上的驻点的能量分析得出CICO+O_2是主要的通道,CO_2+Cl+O、CO_2+CIO和OCO_2+Cl是次要通道,通道CO+O_2+Cl在动力学上是最少的。本研究工作将为控制氯代次甲基对臭氧层的破坏提供理论依据。
The depletion of the ozone layer is one of the important environmental problems. The chlorinated methylidyne radical produced by UV photolysis of CFC in the stratosphere will consume the ozone. In order to clarify the ozone depletion mechanism by the radical, we employed quantum chemical calculations to study the reaction mechanisms of CC1 radical with 03 on the doublet potential energy surface. The geometric structures of reactants, intermediates, transition states and products were optimized at the B3LYP/6-311G（d, p） level, and their vibration frequencies and energy values were obtained. Intrinsic reaction coordinate calculations at the same level were implemented to confirm the connections between transition states and intermediates. The detailed reaction pathways were made clear. It is found that the CCI ＋ 03 reaction possesses five product channels： CICO ＋ 02, CO2 ＋ C1 ＋ O, CO2 ＋ C10, CO ＋ 02 ＋ C1, OCO2 ＋ C1. Through the energy analysis of the stationary points on each reaction pathway, we can drawn the conclusion that the CICO ＋ 02 channel is the most feasible, CO2 ＋ C1 ＋ O, CO2 ＋ C10 and OCO2 ＋ CI are all secondary channels, the CO ＋ 02 ＋ CI channel is the least competitive. This research will provide theoretical basis for controlling the destruction of the ozone layer by the chlorinated methylidyne radical.
出处
《计算机与应用化学》
CAS
CSCD
北大核心
2013年第11期1310-1314,共5页
Computers and Applied Chemistry
基金
湖北省教育厅科学技术研究计划重点项目(D20111105)
武汉科技大学绿色制造与节能减排科技研究中心开放基金(C1201)
湖北大学功能材料绿色制备与应用重点实验室开放基金(000-046034)资助
关键词
理论计算
反应机理
氯代次甲基(CCI)
臭氧(O3)
theoretical calculation
reaction mechanism
chlorinated methylidyne radical （CC1）
ozone （03）
