NO_x存在下异戊二烯与OH自由基大气化学反应

An Experimental Study for Atmospheric Chemistry of Isoprene with OH Radicals in the Presence of NO x

采用长光路傅立叶变换红外光谱（ＬＰＦＴＩＲ）技术，研究ＮＯｘ存在下异戊二烯与氢氧自由基（ＯＨ）的模拟大气化学反应。ＯＨ自由基由亚硝酸甲脂（ＣＨ３ＯＮＯ）黑光灯光解产生。结果表明，产物中主要有羰基化合物、硝酸酯或过氧硝酸酯、甲酸（ＨＣＯＯＨ）及ＣＯ等。鉴定出的羰基化合物为甲基丙烯醛（ＣＨ２Ｃ（ＣＨ３）ＣＨＯ）、甲基乙烯基酮（ＣＨ３Ｃ（Ｏ）ＣＨＣＨ２）和甲醛（ＨＣＨＯ）。在２９８Ｋ、９３３ｋＰａ时，甲基丙烯醛和甲基乙烯基酮的产率分别为（２０８±１５）％和（３３４±２２）％。压力变化对这两种羰基化合物的产率几乎无影响。最后对ＮＯｘ存在下的异戊二烯／ＯＨ自由基反应进行了简略讨论。

The experimental simulation was employed to study the atmospheric chemistry of i soprene with OH radicals in the presence of NO x,using long path Fourier trans form infrared (LP FTIR) method.OH radical was produced from photodissociation o f CH 3ONO under irradiation of black lights.Results showed that carbonyl compou nds,organic nitrates,HCOOH and CO,were formed.Methacrolein (CH 2 C(CH 3)CHO) ,methyl vinyl ketone (CH 3C(O)CH CH 2) and HCHO were identified.At the temperature of 298?K and the pr essure of 93.3?kPa,yields of methacrolein and methyl vinyl ketone were (20.8±1 .5)% and (33.4±2.2)% respectively.The pressure variation did not influence thei r yields.Finally the reaction of isoprene with OH radical in the presence of NO x was discussed brieflly.