大气中OH引发的有机磷农药MTMPDA降解机理的研究

OH-initiated degradation reaction mechanisms of MPMTDA in the atmosphere

采用量子化学方法在ωB97XD/6-311++G(3df,2pd)//ωB97XD/6-31+G(d,p)和M062X/6-311++G(3df,2pd)//M062X/6-31+G(d,p)水平下对大气中MTMPDA在OH自由基引发下的反应机理及其产物的后继反应进行理论研究.结果表明MTMPDA+OH反应主要通过OH抽提与N原子相连的—CH3上的H原子、以及抽提与O原子相连的—CH3上的H原子的方式进行.此外,抽提与N原子相连的—CH3上的H原子生成的产物与大气中的O2和NO发生进一步反应并没有导致MTMPDA毒性明显地降低;而抽提与O原子相连的—CH3上的H原子的产物发生一系列后继反应可以降低MTMPDA的毒性.

Using ωB97XD/6-311＋＋G（3df,2pd）//ωB97XD/6-31＋G（d,p） and M062X/6-311＋＋G（3df,2pd） //M062X/6-31＋G（d,p） levels of quantum chemistry theory, the reaction mechanism and subsequent reactions of MTMPDA with OH in the atmosphere were investigated. The results indicate that OH-initiated MTMPDA undergoes via two H-abstraction channels, i.e., N— CH3 and O— CH3. Moreover, the product of abstraction from N— CH3 has no obvious influence on the toxicity of MTMPDA after reaction with O2 and NO in the atmosphere, while the product of abstraction from O— CH3 will reduce the toxicity of MTMPDA.