Micro-mechanism and rate constants for OH-initiated degradation of methomyl in atmosphere.
The atmospheric degradation reactions of the two isomers of methomyl (MTL) initiated by OH radical in the presence of O2, NO and H2O have been investigated by density functional theory (DFT). The calculations were all carried out at MPWB1K level. The geometrical parameters and vibrational frequencies of stationary points were calculated with 6-31+G (d, p) basis sets. Single-point energy calculations were performed with 6-311+G (3df, 2p) basis sets. Profiles of the potential energy surface were constructed and all possible channels involved in the reactions were discussed. The rate constants of main elementary reactions were calculated over a temperature range of 200-400 K and mostly fitted to Arrhenius formulas. The atmospheric lifetimes of reaction species were discussed for the first time, which can be applied to the study on model simulation and management of hazardous materials.
Environment Research Institute, Shandong University, Jinan 250100, PR China.
Xiuchao
X
Wu
Environment Research Institute, Shandong University, Jinan 250100, PR China. Electronic address: sxmwch@sdu.edu.cn.
Xiaomin
X
Sun
Environment Research Institute, Shandong University, Jinan 250100, PR China.
Chenxi
C
Zhang
Environment Research Institute, Shandong University, Jinan 250100, PR China.
Chen
C
Gong
Environment Research Institute, Shandong University, Jinan 250100, PR China.
Jingtian
J
Hu
D001272:Atmosphere / Q000737:chemistry*; D004785:Environmental Pollutants / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry*; D007700:Kinetics; D008724:Methomyl / Q000737:chemistry*; D009569:Nitric Oxide / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D011789:Quantum Theory; D013696:Temperature; D013816:Thermodynamics
D004785:Environmental Pollutants; D008724:Methomyl; D009569:Nitric Oxide; D017665:Hydroxyl Radical; D010100:Oxygen
Degradation mechanism; Hydroxyl radical; Methomyl; Rate constant