甲醛与臭氧反应机理的理论研究

Theoretical study on reaction mechanism between ozone and formaldehyde

从量子化学理论角度探讨了甲醛在有水条件与无水条件下的臭氧氧化机理.主要应用密度泛函中的MPW1K方法,结合6-31+G(d,p)基组优化了反应物、中间体、过渡态以及产物的结构,并计算了各个化合物的振动频率.通过内禀反应坐标的计算确认了反应物、过渡态和产物的相关性.为了得到准确的能量信息,用HL方法进一步精确计算了反应路径上所有结构的能量.结果发现,在有水条件下甲醛与臭氧反应活化能更高,对反应不利.

A theoretical study of hydrogen abstraction reactions is presented from formaldehyde by sozone molecule both under water vapor condition and without water vapor condition.The geometries,harmonic vibrational frequencies of all stationary points are calculated at MPW1K level of theory.The energies of all the stationary points are refined by higher-level （denoted as HL） energy calculations.The minimum energy paths （MEPs） were obtained by the MPW1K/6-31＋G（d,p） level of theory.The reaction mechanisms of ozone-formaldehyde at the two conditions are discussed.The results show that hydrogen abstraction reactions will be more favourable at anhydrous condition.