氯原子引发的甲基过氧化氢大气光化学反应  

Study on Atmospheric Photo-oxidation of Methyl Hydroperoxide Initiated by Cl-atom

作　　者：史飞[1] 陈忠明[1] 

机构地区：[1]北京大学环境学院,环境模拟与污染控制国家重点联合实验室,北京100871

出　　处：《光谱学与光谱分析》2004年第1期65-67,共3页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金 (2 0 1 0 70 0 1 )资助项目

摘　　要：有机过氧化物在大气化学过程中起着重要作用 ,并对城市大气质量有着重要影响 ,然而 ,目前对它们大气化学行为的了解还非常不够 ,尤其缺少定量的研究。文章利用长光路傅里叶变换红外光谱 (长光路FTIR)仪原位跟踪反应进程 ,进行实验室模拟研究大气中非常重要的一种有机过氧化物 ,即甲基过氧化氢(CH3OOH ,MHP)的大气光化学反应。反应在内配有红外光多次反射镜 (White镜 )的 2 8 5L静态石英反应池中进行 ,采用氯原子 (Cl)引发反应 ,温度为 (2 92± 2 )K ,压力为 9 3× 10 4 Pa(2 0 %O2 +80 %N2 )。FTIR光谱表明反应产物中主要包括甲醛 (HCHO)、甲酸 (HCOOH)、一氧化碳 (CO)和二氧化碳 (CO2 ) ,此外还有少量的甲醇 (CH3OH)生成。测定了前三种主要产物在反应 6 0min内的产率 :HCOOH和CO产率分别为 2 4 %和 6 % ;而HCHO浓度先增后减 ,浓度达到峰值时产率为 5 0 %。根据实验结果探讨了可能的反应机理 ,指出MHP是大气中HOx 自由基的储库分子 。Organic peroxides play an important role in chemistry of the atmosphere and in controlling urban air quality; however, accurate knowledge about their atmospheric reactions is lacking. In this paper, the experimental simulation was employed to study the atmospheric photo-oxidation of methyl hydroperoxide (CH 3OOH, MHP), a key organic peroxide in the atmosphere. At the temperature of (292±2)K and pressure of 9.3×10 4 Pa (20% O 2+80% N 2), the MHP photo-oxidation was initiated by Cl-atom and the process of reaction was in-situ observed by long path Fourier transform infrared (Long Path FTIR) spectrometry. From FTIR spectra, the main products observed were formaldehyde (HCHO), formic acid (HCOOH), carbon monoxide (CO) and carbon dioxide (CO 2), and minor methanol (CH 3OH) was found as well. Within the reaction period of 60 min, yields were determined: 24% for HCOOH and 6% for CO; 50% for HCHO at its maximum concentration although its yield was varying with the reaction time. Finally, reaction mechanisms were discussed, which implied that MHP is a reservoir of odd-hydrogen radicals (HO x) and plays an important role in atmospheric photo-reactions.

关 键 词：甲基过氧化氢 大气化学 光化学氧化剂 氯原子 反应机理 自由基 光化学反应 

分 类 号：P402[天文地球—大气物理学与大气环境] O641.3[天文地球—大气科学及气象学]