OH自由基引发的甲烷光化学氧化体系中有机过氧化物的研究
STUDIES ON THE FORMATION OF ORGANIC PEROXIDES IN THE OH-INITIATED OXIDATION OF CH4
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摘要: 在1.01325×105Pa,298K,O2-N2气氛下,采用长光路付立叶红外光谱仪跟踪反应进程,高压液相色谱仪测定反应产物中有机过氧化物,研究了OH自由基引发的甲烷光化学反应体系,证实反应产物中有H2O2、甲基过氧化氢(CH3O2H,MHP)和过氧甲醚(CH3O2CH3),并发现羟甲基过氧化氢(HOCH2OOH,HMHP)和一未知有机过氧化物.HMHP的发现表明CH4氧化过程中可能存在过氧甲基CH3O2·自由基自身复合产生Criegee双自由基中间体·CH2OO·的途径.模拟实验显示甲烷光化学氧化产生有机过氧化物的机制比以往认为的要更为复杂.甲烷的光化学氧化可能是大气对流层有机过氧化物的重要来源.Abstract: Formation of Organic peroxides in the OH-initiated photooxidation of CH4 in O2-N2 mixtures at 1. 01325�105 Pa and 298K was studied with HPLC and FT-IR methods. The results of HPLC analysis showed that five peaks were found in the chromatogram .and the four of them were identified as H2O2, HOCH2OOH(HMHP), CH3O2H(MHP) and CH3OZCH3 based on their retention times,among which HMHP was first reported, while the other unknown peak of 8. OSmin was assigned tentatively to HC(O)OOH. The formation of HMHP in the reaction system indicated that there was a probable path for CH3O2 radicals to produce Criegee biradical·CH2OO·. The formation mechanism of organic peroxides in the photooxidation of CH4 was more complicated than it had been assumed before. Photooxidation of CH4 probably was an important source of organic peroxides in the troposphere.
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Key words:
- methane /
- HPLC /
- FT-IR /
- photochemical reaction /
- organic peroxides
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