摘要
采用量子化学计算方法,几何构型在M062X/6-31+G(d,p)理论水平,单点能在M062X/6-311++G(3df,2pd)理论水平下,对大气中O,S-二甲基-甲基硫代磷酸酯(OSDMMP)与OH自由基反应的降解过程进行了详细的机理研究。结果显示:整个反应过程需要经历3个氢抽提反应通道,经过这3个反应通道分别生成3种不同的产物,即产物1 CH_3SP(O)(CH_3)OCH_2、产物2 CH_2SP(O)(CH_3)OCH_3和产物3 CH_3SP(O)(CH_2)OCH_3,其中生成产物1和产物2所需要跨越的能垒比生成产物3要低,在发生反应时的竞争优势更为明显;产物1CH_3SP(O)(CH_3)OCH_2和产物2 CH_2SP(O)(CH_3)OCH_3在环境中与氧化剂NO和O_2发生后继反应所生成的最终产物其毒性比反应物OSDMMP有明显的降低,而产物3 CH_3SP(O)(CH_2)OCH_3的最后降解产物其毒性与OSDMMP相近。
Using quantum chemistry methods,the mechanisms of O,S-dimethyl methylphosphonothioate(OSDMMP)with OH reaction and the subsequent reactions in atmosphere were investigated.Optimization was performed with density functional theory(DFT)at the M062X/6-31+G(d,p)levels of theory,and the singlet point energy was refined by M062X/6-311++G(3df,2pd).The results indicate that hydrogen-abstraction mechanism involved with three different products are formed,i.e.,CH3SP(O)(CH3)OCH2,CH 2SP(O)(CH3)OCH3 and CH 3SP(O)(CH2)OCH3.The formations of CH 3SP(O)(CH3)OCH2 and CH2SP(O)(CH3)OCH3 surpass much lower barriers than that of CH 3SP(O)(CH2)OCH3,so the former two products are dominant in the title reaction.Subsequent reactions of the former two products with O2 and NO in atmosphere reduce toxicity of the initial reactant OSDMMP obviously,while eventual degradation products of CH 3SP(O)(CH2)OCH3 makes minor contributions to the toxicity of OSDMMP.
作者
路成刚
童毅
唐沂珍
冯兰
吕谋
LU Chenggang;TONG Yi;TANG Yizhen;FENG Lan;LYU Mou(School of Environmental and Municipal Engineering,Qingdao University of Technology,Qingdao 266033,China;Shandong Province Department of Environmental Protection,Jinan 250012,China)
出处
《济南大学学报（自然科学版）》
CAS
北大核心
2018年第6期459-462,共4页
Journal of University of Jinan(Science and Technology)
基金
国家自然科学基金项目(41775119
51478230)
青岛市博士后基金项目(A2014-083)
关键词
有机磷农药
O
S-二甲基-甲基硫代磷酸酯
降解机理
organophosphorus pesticide
O,S-dimethyl methylphosphonothioate
degradation mechanism
