Heterogeneous reactions of methacrolein and methyl vinyl ketone: Kinetics and mechanisms of uptake and ozonolysis on silicon dioxide

Chen, Z. M.; Jie, C. Y.; Li, S.; Wang, H. L.; Wang, C. X.; Xu, Jiele; Hua, W.

doi:10.1029/2007jd009754

Cited by 29 publications

(37 citation statements)

References 84 publications

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“…Nighttime is usually more humid than daytime, increasing the significance of aqueous-phase and heterogeneous reactions. Recent laboratory studies have suggested that H 2 O 2 and ROOH could also be produced during aqueous-phase reactions and heterogeneous reactions on particles [Chen et al, 2008a[Chen et al, , 2008bZhang et al, 2009]. On 25 July concentrations of C 2 -C 11 alkenes decreased from 4.5 to 3.3 ppbv during 1800-2000, which is when the peroxides accumulated.…”

Section: Nighttime Production Of Peroxidesmentioning

confidence: 99%

Measurement of atmospheric hydrogen peroxide and organic peroxides in Beijing before and during the 2008 Olympic Games: Chemical and physical factors influencing their concentrations

He¹,

Chen²,

Zhang³

et al. 2010

J. Geophys. Res.

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[1] For the 2008 Beijing Olympic Games full-scale control (FSC) of atmospheric pollution was implemented to improve the air quality from 20 July to 20 September 2008, resulting in a significant decrease in the emission of pollutants in urban Beijing, especially vehicular emissions. The combination of reduced emissions and weather condition changes provided us with a unique opportunity to investigate urban atmospheric chemistry. Hydrogen peroxide (H 2 O 2 ) and organic peroxides play significant roles in atmospheric processes, such as the cycling of HO x radicals and the formation of secondary sulfate aerosols and secondary organic aerosols. We measured atmospheric H 2 O 2 and organic peroxides in urban Beijing, at the Peking University campus, from 12 July to 30 September, before and during the FSC. The major peroxides observed were H 2 O 2 , methyl hydroperoxide (MHP), and peroxyacetic acid (PAA), having maximal mixing ratios of 2.34, 0.95, and 0.17 ppbv (parts per billion by volume), respectively. Other organic peroxides were detected occasionally, such as bis-hydroxymethyl hydroperoxide, hydroxymethyl hydroperoxide, ethyl hydroperoxide, and 1-hydroxyethyl hydroperoxide. On sunny days the concentrations of H 2 O 2 , MHP, and PAA exhibited pronounced diurnal variations, with a peak in the afternoon (1500-1900) and, occasionally, a second peak in the evening (2000-0200). The night peaks can be attributed to local night production from the ozonolysis of alkenes, coupled with the reaction between NO 3 radicals and organic compounds. Sunny-day weather dominated during 16-26 July, and we found that the concentrations of H 2 O 2 , MHP, and PAA increased strikingly on 22-26 July, compared with the concentrations during 16-19 July. This effect was mainly attributed to the NO x (NO and NO 2 ) decline because of the FSC, due to (i) the suppressing effect of NO and NO 2 on the production of peroxides and (ii) the indirect effect of reduced NO x on the concentration of peroxides via O 3 production in the volatile organic compound-sensitive area. Although the time period from 29 July to 15 August fell within the FSC, the concentrations of H 2 O 2 , MHP, and PAA decreased significantly. This can be explained by a combination of chemical and physical factors during this period, when rainy-and cloudy-day weather dominated. Weaker irradiation and lower temperatures resulted in a lower photochemical production of peroxides; the higher humidity resulted in their greater loss through their aqueous-phase oxidation of S(IV) and through heterogeneous removal, and lower temperatures and higher nighttime humidity resulted in a quicker surface deposition of peroxides. Furthermore, our observations seem to imply that the heterogeneous removal of H 2 O 2 is faster than that of MHP, as indicated by the strong negative correlation between the H 2 O 2 -to-MHP ratio and the aerosol surface area.

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Section: Nighttime Production Of Peroxidesmentioning

confidence: 99%

Measurement of atmospheric hydrogen peroxide and organic peroxides in Beijing before and during the 2008 Olympic Games: Chemical and physical factors influencing their concentrations

He¹,

Chen²,

Zhang³

et al. 2010

J. Geophys. Res.

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“…The details of the sample processing and analysis are described in our previous work. [50][51][52] Blanks were sampled and analysed using the same method before the reaction.…”

Section: Instrumentation and Methodsmentioning

confidence: 99%

Photochemical reactions of methyl and ethyl nitrate: a dual role for alkyl nitrates in the nitrogen cycle

Chen

Zhang

2011

Environ. Chem.

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Environmental context. Alkyl nitrates are considered to be important intermediates in the atmospheric hydrocarbons-nitrogen oxides-ozone cycle, which significantly determines air quality and nitrogen exchange between the atmosphere and the Earth's surfaces. The present laboratory study investigates reaction products of alkyl nitrates to elucidate their photochemical reaction mechanisms in the atmosphere. The results provide a better understanding of the role played by alkyl nitrates in the atmospheric environment.Abstract. Alkyl nitrates (ANs) are important nitrogen-containing organic compounds and are usually considered to be temporary reservoirs of reactive nitrogen NO x (NO 2 and NO) in the atmosphere, although their atmospheric fates are incompletely understood. Here a laboratory study of the gas-phase photolysis and OH-initiated reactions of methyl nitrate (CH 3 ONO 2 ) and ethyl nitrate (C 2 H 5 ONO 2 ), as models of atmospheric ANs, is reported with a focus on elucidating the detailed photochemical reaction mechanisms of ANs in the atmosphere. A series of intermediate and end products were well characterised for the first time from the photochemical reactions of methyl and ethyl nitrate conducted under simulated atmospheric conditions. Notably, for both the photolysis and OH-initiated reactions of CH 3 ONO 2 and C 2 H 5 ONO 2 , unexpectedly high yields of HNO 3 (photochemically non-reactive nitrogen) were found and also unexpectedly high yields of peroxyacyl nitrates (RC(O)OONO 2 , where R ¼ H, CH 3 , CH 3 CH 2 ,y) (reactive nitrogen) have been found as CH 3 C(O)OONO 2 in the C 2 H 5 ONO 2 reaction or proposed as HC(O)OONO 2 in the CH 3 ONO 2 reaction. Although the yields of HNO 3 from the ANs under ambient conditions are likely variable and different from those obtained in the laboratory experiments reported here, the results imply that the ANs could potentially serve as a sink for reactive nitrogen in the atmosphere. The potential for this dual role of organic nitrates in the nitrogen cycle should be considered in the study of air quality and nitrogen exchange between the atmosphere and surface. Finally, an attempt was made to estimate the production of HNO 3 and peroxyacyl nitrates derived from NO x by ANs as intermediates in the atmosphere.

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“…Methacrolein (MACR) and methyl vinyl ketone (MVK), as two major first-generation products in the oxidation of isoprene, are of great interest due to their large global abundance (Montzka et al, 1993;Griffin et al, 1999;Simpson et al, 1999) and high reactivity (Gierczak et al, 1997;Chen et al, 2008b). The atmospheric transformation of these two carbonyls has received considerable studies, mainly including determining their gas-phase reaction products Atkinson, 1989, 1990;Aschmann et al, 1996;Orlando et al, 1999), measuring aerosol growth from their photooxidation Ng et al, 2006), elucidating reaction pathways in terms of SOA formation (Kroll et al, 2005;Surratt et al, 2006;Szmigielski et al 2007), and investigating their uptake kinetics onto particles (Nozière et al, 2006;Chen et al, 2008a;Zhao et al, 2010). Chamber experiments have demonstrated that MACR is an important intermediate in SOA formation whereas MVK was found to produce no SOA Surratt et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Laboratory simulation for the aqueous OH-oxidation of methyl vinyl ketone and methacrolein: significance to the in-cloud SOA production

2010

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Increasing evidence suggests that secondary organic aerosol (SOA) is formed through aqueous phase reactions in atmospheric clouds. In the present study, the aqueous oxidation of methyl vinyl ketone (MVK) and methacrolein (MACR) via OH radical were investigated, with an emphasis on the composition and variation of small-molecular-weight organic products. In addition, high-molecular-weight compounds (HMWs) were found, interpreted as the ion abundance and time evolution. Our results provide, for the first time to our knowledge, experimental evidence that aqueous OH-oxidation of MVK contributes to SOA formation. Further, a mechanism primarily involving radical processes was proposed to gain a basic understanding of these two reactions. Based on the assumed mechanism, a kinetic model was developed for comparison with the experimental results. The model reproduced the observed profiles of first-generation intermediates, but failed to simulate the kinetics of most organic acids mainly due to the lack of chemical kinetics parameters for HMWs. A sensitivity analysis was performed in terms of the effect of stoichiometric coefficients for precursors on oxalic acid yields and the result indicates that additional pathways involving HMWs chemistry might play an important role in the formation of oxalic acid. We suggest that further study is needed for better understanding the behavior of multi-functional products and their contribution to the oxalic acid formation

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Heterogeneous reactions of methacrolein and methyl vinyl ketone: Kinetics and mechanisms of uptake and ozonolysis on silicon dioxide

Cited by 29 publications

References 84 publications

Measurement of atmospheric hydrogen peroxide and organic peroxides in Beijing before and during the 2008 Olympic Games: Chemical and physical factors influencing their concentrations

Measurement of atmospheric hydrogen peroxide and organic peroxides in Beijing before and during the 2008 Olympic Games: Chemical and physical factors influencing their concentrations

Photochemical reactions of methyl and ethyl nitrate: a dual role for alkyl nitrates in the nitrogen cycle

Laboratory simulation for the aqueous OH-oxidation of methyl vinyl ketone and methacrolein: significance to the in-cloud SOA production

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