Effect of Water Molecule on the Complete Series Reactions of Chlorothiobenzenes with H/·OH: A Theoretical Study

Atmosphere

Yanhui Sun¹  Fei Xu²  Zhuochao Teng²  Mohammad Hassan Hadizadeh²  Yanan Han²  Qi Zhang²  Siyuan Zheng³ 

[1] College of Environment and Safety Engineering, Qingdao University of Science & Technology, Qingdao 266042, China;Environment Research Institute, Shandong University, Qingdao 266237, China;Institute for Energy and Climate, Forschungszentrum Jülich, 52425 Jülich, Germany;

关键词: chlorothiobenzenes;    chlorothiobenzyl radicals;    H/·OH;    water molecule;    catalysis effect;   

DOI  :  10.3390/atmos13050849

来源: DOAJ

【 摘 要 】

The chlorothiobenzenes (CTBs) are the principal precursors for the formation of polychlorinated thianthrene/dibenzothiophenes (PCTA/DTs), which have high toxicity and wide distribution in the environment. Under the pyrolysis or combustion conditions, CTBs can react with H/·OH radicals to form the chlorothiobenzyl radicals (CTBRs) through abstraction of the chlorothiobenzyl-hydrogen. The water molecule can play an important role in this process. The coupling of CTBRs is the essential first step in forming PCTA/DTs. In this paper, quantum chemical calculations were carried out to investigate the formation of CTBRs from the complete series reactions of 19 chlorothiobenzene (CTB) congeners with H/·OH radicals in the presence of the water molecule. Using the MPWB1K/6-311 + G(3df,2p)//MPWB1K/6-31 + G(d,p) energy level, schematic energy profiles were constructed with the water molecule and then compared with the non-hydrated case. The present study shows that structural parameters and thermal data, as well as CTBRs formation potential from CTBs, are strongly dominated by the chlorine substitution at the ortho-position of CTBs. Meanwhile, the water molecule can promote the CTBR formation from CTBs abstracted by H/·OH, which has a stronger catalysis effect on the H abstraction from CTBs by OH than from CTBs by H. This study may provide reference parameters for future experimental research, which would enhance measures to reduce dioxin emission and establish dioxin control strategies.

【 授权许可】

Unknown