Theoretical Study On The Degradation Mechanism Of The Environmental Endocrine In Atmosphere

Environmental endocrine is exogenous chemicals which interfere with endocrine organisms. It is also known as endocrine disrupter. According to preliminary research, it is confirmed that we found at least eighty of environmental endocrine having a harmful effect to human an animal hormones. Common environmental endocrine including phthalate esters, methomyl, alkylphenol, dioxin, PCBs, polychlorinated biphenyls ether, bisphenol A and so on. Most environmental endocrine also belong to "persistent organic pollutants", it is very stable and difficult to decompose, so it can exist a long time and not easy to cleare. Persistent organic pollutants are toxic, hard-degradation and biological cumulative, plus the terrible Grasshopper Effect so it will enhance its contagion.Part of the pollutants in the high temperature area will easy volatilize into the atmosphere, with the wind it will move into low temperature area, then condensation and down with rainfall into ground surface, when temperatures grow up again, pollutants will into the air, and repeat evaporate, migration and sink. Through the air, water and adsorbate it will emit into other clean area. Environment endocrine application give human brought obvious economic benefit, but also brings human increasingly serious environmental problems. Now, people have realized its harmful effects, countries already started to pay attention to and begins the scientists to solve this problem.In this paper we select diethyl phthalate methomly and 4-tert-Butylphenol as the representative environmental endocrine to be investigated. All the results were obtained at the MPWB1K/6-311+G(3df,2p)//MPWB1K/6-31+G(d,p) level using Gaussian 03 program. Major valuable results are listed as follows:1. The OH-initiated oxidation reactions are the main degradation channels for DEP in the atmosphere. The main reactions between OH and DEP are H abstractions and OH additions to benzene ring.2. During the degradation reactions for methomyl, H abstractions from three CH3 groups and the addition reactions to N=C double bond are the main reactions between methomyl and OH. The intermediates of first are readily oxidized by O2/NO in the atmosphere.3. In the daytime the H of TBP will be abstracted by the OH, and at night, the H will be abstracted by the NO3. Then the intermediates IM1 and IM2 will further react with O2, NO and NO2.