Investigation of the Gas-Phase Photolysis and Temperature-Dependent OH Reaction Kinetics of 4-Hydroxy-2-butanone

详细信息    查看全文

• 作者：Hichem Bouzidi ; Lina Aslan ; Gis猫le El Dib ; Patrice Coddeville ; Christa Fittschen ; Alexandre Tomas
• 刊名：Environmental Science & Technology
• 出版年：2015
• 出版时间：October 20, 2015
• 年：2015
• 卷：49
• 期：20
• 页码：12178-12186
• 全文大小：406K
• ISSN：1520-5851

文摘

Hydroxyketones are key secondary reaction products in the atmospheric oxidation of volatile organic compounds (VOCs). The fate of these oxygenated VOCs is however poorly understood and scarcely taken into account in atmospheric chemistry modeling. In this work, a combined investigation of the photolysis and temperature-dependent OH radical reaction of 4-hydroxy-2-butanone (4H2B) is presented. The objective was to evaluate the importance of the photolysis process relative to OH oxidation in the atmospheric degradation of 4H2B. A photolysis lifetime of about 26 days was estimated with an effective quantum yield of 0.08. For the first time, the occurrence of a Norrish II mechanism was hypothesized following the observation of acetone among photolysis products. The OH reaction rate coefficient follows the Arrhenius trend (280鈥?58 K) and could be modeled through the following expression: k_4H2B(T) = (1.26 卤 0.40) 脳 10^鈥?2 脳 exp((398 卤 87)/T) in cm³ molecule^鈥? s^鈥?. An atmospheric lifetime of 2.4 days regarding the OH + 4H2B reaction was evaluated, indicating that OH oxidation is by far the major degradation channel. The present work underlines the need for further studies on the atmospheric fate of oxygenated VOCs.