(CH_3)_2C=CH_2臭氧化的中间产物与二次有机气溶胶形成的关联
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- 英文论文题名：Role of the intermediates for the formation of secondary organic aerosol in 2-methyl propene ozonolysis
- 论文作者：赵强莉 ; 刘峰毅 ; 王文亮
- 英文论文作者：Qiangli Zhao ; Fengyi Liu ; Wenliang Wang ; Key Laboratory for Macromolecular Science of Shaanxi Province ; School of Chemistry and Chemical Engineering ; Shaanxi Normal University
- 年：2016
- 作者机构：陕西省大分子科学重点实验室陕西师范大学化学化工学院;
- 论文关键词：二次有机气溶胶 ; Criegee中间体 ; 结构和构型 ; 密度泛函理论
- 会议召开时间：2016-07-01
- 会议录名称：中国化学会第30届学术年会摘要集-第四十四分会：化学动力学
- 语种：中文
- 分类号：O631.5
- 学会代码：ZGHY
- 会议名称：中国化学会第30届学术年会-第四十四分会 ; 化学动力学
- 会议地点：中国辽宁大连
- 主办单位：中国化学会
- 学会名称：中国化学会
- 页数：1
- 文件大小：467k
- 原文格式：D
- 会议级别：全国
摘要
烯烃臭氧化是二次有机气溶胶(SOA)的重要来源,本文采用M06-2X/6-311+G(2df,2p)//M06-2X/6-311+G(d,p)方法,以2-甲基丙烯(CH_3)_2C=CH_2臭氧化过程为研究对象,研究了由Criegee中间体(CI)为重复单元的氢过氧化低聚物ROO(CI)_nH的生成机理。对比了Sadezky提出的烷基过氧自由基(RO_2)为引发剂,稳定CI(SCI)连续加成并与HO_2自由基反应的生成机理和Sakamoto提出以稳定的CI(SCI)连续加成到氢过氧化物(ROOH)的生成机理,并深入分析了RO_2和ROOH结构和构型,以及SCI结构与低聚物形成的关联。研究表明:除HCOOH外,不同结构的RO_2,ROOH均有螺旋状、锯齿状和环状三种稳定构型,对于三种构型均呈现出CI与RO_2的反应能垒更低的结果,即反应更倾向于以Sadezky所提机理进行(见表1)。反应能垒的高低与RO_2及ROOH的结构和构型紧密相关。CH_2OO参与反应的能垒比(CH3)_2COO参与的能垒更低;随着低聚物链长增加,反应的能垒呈现出整体增大的趋势。均聚低聚物的形成过程的反应能垒低于共聚低聚物的形成过程。
Ozonolysis of alkenes is an important source of secondary organic aerosol in the atmosphere. In this study, ozonolysis of 2-methyl propene, as a proxy for small alkenes, was investigated with an emphasis on formation mechanism of oligomeric hydroperoxides ROO(CI)_nH composed of the Criegee intermediate(CI) as a chain unit. The results shows that, the formations of the oligomers prefer to follow the mechanism involving initiation by the reaction of an alkylperoxy radical(ROO) and stabilized CI(SCI), sequential addition of SCIs, and termination by the HO_2 radical, rather than follow the mechanism that sequential addition of CI to hydroperoxides(ROOH). The height of the reaction energy barrier is closely related to the structures and configurations of RO_2 and ROOH. The energy barriers of the oligomerization involves CH_2OO are lower than that involving(CH_3)_2COO.The energy barriers increases as the chain length increases. Compared with the formation of cooligomer, that of homooligomer proceeds more easily.
Ozonolysis of alkenes is an important source of secondary organic aerosol in the atmosphere. In this study, ozonolysis of 2-methyl propene, as a proxy for small alkenes, was investigated with an emphasis on formation mechanism of oligomeric hydroperoxides ROO(CI)_nH composed of the Criegee intermediate(CI) as a chain unit. The results shows that, the formations of the oligomers prefer to follow the mechanism involving initiation by the reaction of an alkylperoxy radical(ROO) and stabilized CI(SCI), sequential addition of SCIs, and termination by the HO_2 radical, rather than follow the mechanism that sequential addition of CI to hydroperoxides(ROOH). The height of the reaction energy barrier is closely related to the structures and configurations of RO_2 and ROOH. The energy barriers of the oligomerization involves CH_2OO are lower than that involving(CH_3)_2COO.The energy barriers increases as the chain length increases. Compared with the formation of cooligomer, that of homooligomer proceeds more easily.
引文
[1]Sakamoto,Y.;Inomata,S.;Hirokawa,J.Phys.Chem.A 2013,117:12912.
[2],G.;Chaimbault,P.;Moortgat,G.K.Atmos.Chem.Phys.2008,8:2667
[2],G.;Chaimbault,P.;Moortgat,G.K.Atmos.Chem.Phys.2008,8:2667