Atmospheric aqueous phase radical chemistry of the isoprene oxidation products methacrolein, methyl vinyl ketone, methacrylic acid and acrylic acid – kinetics and product studies

2014 ◽  
Vol 16 (13) ◽  
pp. 6257 ◽  
Author(s):  
Luisa Schöne ◽  
Janine Schindelka ◽  
Edyta Szeremeta ◽  
Thomas Schaefer ◽  
Dirk Hoffmann ◽  
...  
Keyword(s):  
Acrylic Acid ◽  
Aqueous Phase ◽  
Methacrylic Acid ◽  
Vinyl Ketone ◽  
Methyl Vinyl Ketone ◽  
Oxidation Products ◽  
Methyl Vinyl ◽  
Radical Chemistry ◽  
Isoprene Oxidation ◽  
Isoprene Oxidation Products

scholarly journals Production of methyl vinyl ketone and methacrolein via the hydroperoxyl pathway of isoprene oxidation

2013 ◽  
Vol 13 (11) ◽  
pp. 5715-5730 ◽  
Author(s):  
Y. J. Liu ◽  
I. Herdlinger-Blatt ◽  
K. A. McKinney ◽  
S. T. Martin
Keyword(s):  
Reaction Pathway ◽  
Vinyl Ketone ◽  
Methyl Vinyl Ketone ◽  
Oxidation Products ◽  
Peroxyl Radicals ◽  
Cold Trap ◽  
Product Analysis ◽  
Methyl Vinyl ◽  
Isoprene Oxidation ◽  
Tof Ms

Abstract. The photo-oxidation chemistry of isoprene (ISOP; C5H8) was studied in a continuous-flow chamber under conditions such that the reactions of the isoprene-derived peroxyl radicals (RO2) were dominated by the hydroperoxyl (HO2) pathway. A proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS) with switchable H3O+ and NO+ reagent ions was used for product analysis. The products methyl vinyl ketone (MVK; C4H6O) and methacrolein (MACR; C4H6O) were differentiated using NO+ reagent ions. The MVK and MACR yields via the HO2 pathway were (3.8 ± 1.3)% and (2.5 ± 0.9)%, respectively, at +25 °C and < 2% relative humidity. The respective yields were (41.4 ± 5.5)% and (29.6 ± 4.2)% via the NO pathway. Production of MVK and MACR via the HO2 pathway implies concomitant production of hydroxyl ((6.3 ± 2.1)%) and hydroperoxyl ((6.3 ± 2.1)%) radicals, meaning a HOx recycling of (12.6 ± 4.2)% given that HO2 was both a reactant and product. Other isoprene oxidation products, believed to be mostly organic hydroperoxides, also contributed to the ion intensity at the same mass-to-charge (m/z) ratios as the MVK and MACR product ions for HO2-dominant conditions. These products were selectively removed from the gas phase by placement of a cold trap (−40 °C) inline prior to the PTR-TOF-MS. When incorporated into regional and global chemical transport models, the yields of MVK and MACR and the concomitant HOx recycling reported in this study can improve the accuracy of the simulation of the HO2 reaction pathway of isoprene, which is believed to be the fate of approximately half of atmospherically produced isoprene-derived peroxy radicals on a global scale.

Within‐plant isoprene oxidation confirmed by direct emissions of oxidation products methyl vinyl ketone and methacrolein

2011 ◽  
Vol 18 (3) ◽  
pp. 973-984 ◽  
Author(s):  
Kolby J. Jardine ◽  
Russell K. Monson ◽  
Leif Abrell ◽  
Scott R. Saleska ◽  
Almut Arneth ◽  
...  
Keyword(s):  
Vinyl Ketone ◽  
Methyl Vinyl Ketone ◽  
Oxidation Products ◽  
Methyl Vinyl ◽  
Isoprene Oxidation

scholarly journals Aqueous-phase ozonolysis of methacrolein and methyl vinyl ketone: a potentially important source of atmospheric aqueous oxidants

2008 ◽  
Vol 8 (8) ◽  
pp. 2255-2265 ◽  
Author(s):  
Z. M. Chen ◽  
H. L. Wang ◽  
L. H. Zhu ◽  
C. X. Wang ◽  
C. Y. Jie ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Vinyl Ketone ◽  
Methyl Vinyl Ketone ◽  
Oxidation Products ◽  
Laboratory Simulation ◽  
Aerosol Formation ◽  
Methyl Vinyl ◽  
Gas Phase Oxidation ◽  
Acid Catalyzed ◽  
Catalyzed Oxidation

Abstract. Recent studies indicate that isoprene and its gas-phase oxidation products could contribute a considerable amount of aerosol through aqueous-phase acid-catalyzed oxidation with hydrogen peroxide (H2O2), although the source of H2O2 is unclear. The present study revealed a potentially important route to the formation of aqueous oxidants, including H2O2, from the aqueous-phase ozonolysis of methacrolein (MAC) and methyl vinyl ketone (MVK). Laboratory simulation was used to perform the atmospheric aqueous-phase ozonolysis at different pHs and temperatures. Unexpectedly high molar yields of the products, including hydroxylmethyl hydroperoxide (HMHP), formaldehyde (HCHO) and methylglyoxal (MG), of both of these reaction systems have been seen. Moreover, these yields are almost independent of pH and temperature and are as follows: (i) for MAC–O3, 70.3±6.3% HMHP, 32.3±5.8% HCHO and 98.6±5.4% MG; and (ii) for MVK–O3, 68.9±9.7% HMHP, 13.3±5.8% HCHO and 75.4±7.9% MG. A yield of 24.2±3.6% pyruvic acid has been detected for MVK–O3. HMHP is unstable in the aqueous phase and can transform into H2O2 and HCHO with a yield of 100%. We suggest that the aqueous-phase ozonolysis of MAC and MVK can contribute a considerable amount of oxidants in a direct and indirect mode to the aqueous phase and that these compounds might be the main source of aqueous-phase oxidants. The formation of oxidants in the aqueous-phase ozonolysis of MAC and MVK can lead to substantial aerosol formation from the aqueous-phase acid-catalyzed reaction of H2O2 with MAC, even if there are no other sources of oxidants.

scholarly journals Production of methyl vinyl ketone and methacrolein via the hydroperoxyl pathway of isoprene oxidation

2012 ◽  
Vol 12 (12) ◽  
pp. 33323-33358 ◽  
Author(s):  
Y. J. Liu ◽  
I. Herdlinger-Blatt ◽  
K. A. McKinney ◽  
S. T. Martin
Keyword(s):  
Variable Temperature ◽  
Vinyl Ketone ◽  
Methyl Vinyl Ketone ◽  
Oxidation Products ◽  
Peroxyl Radicals ◽  
Cold Trap ◽  
Product Analysis ◽  
Methyl Vinyl ◽  
Isoprene Oxidation ◽  
Tof Ms

Abstract. The photo-oxidation chemistry of isoprene (C5H8) was studied in a continuous-flow chamber under conditions such that the reactions of isoprene-derived peroxyl radicals (RO2) were dominated by hydroperoxyl (HO2) pathway. A proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS) with switchable H3O+ and NO+ reagent ions was used for product analysis. The products methyl vinyl ketone (MVK; C4H6O) and methacrolein (MACR; C4H6O) were differentiated using NO+ reagent ions. The MVK and MACR yields were 4.3 ± 0.4% and 3.2 ± 0.3%, respectively, for HO2-dominant conditions at +25 °C and < 2% relative humidity. The respective yields were 41.1 ± 2.2% and 28.8 ± 1.2% for NO-dominant conditions. The yields for HO2-dominant conditions imply a concomitant yield (i.e., recycling factor) of hydrogen oxide radicals (HOx) of 15 ± 0.7% from the reaction of isoprene-derived RO2 with HO2. Other isoprene oxidation products, believed to be organic hydroperoxides, also contributed to the ion intensity at the same mass-to-charge (m/z) ratios as the MVK and MACR product ions, and these products were selectively removed from the gas phase using a variable temperature cold trap (−40 °C) in front of the PTR-TOF-MS. These hydroperoxide products were absent for NO-dominant conditions. When incorporated into regional and global chemical transport models, the yields of MVK and MACR and concomitant HOx yields reported in this study will improve the accuracy of simulations of the HO2 reaction pathway of isoprene, which has been shown to make a significant contribution to the total reactivity of isoprene-derived RO2 radicals on a global scale.

scholarly journals Radical mechanisms of methyl vinyl ketone oligomerization through aqueous phase OH-oxidation: on the paradoxical role of dissolved molecular oxygen

2013 ◽  
Vol 13 (1) ◽  
pp. 2913-2954 ◽  
Author(s):  
P. Renard ◽  
F. Siekmann ◽  
A. Gandolfo ◽  
J. Socorro ◽  
G. Salque ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
High Resolution Mass Spectrometry ◽  
Organic Aerosol ◽  
Vinyl Ketone ◽  
Methyl Vinyl Ketone ◽  
Chemical Mechanism ◽  
Methyl Vinyl ◽  
Phase Chemistry ◽  
Dissolved O2

Abstract. It is now accepted that one of the important pathways of Secondary Organic Aerosol (SOA) formation occurs through aqueous phase chemistry in the atmosphere. However, the liquid phase chemical mechanisms leading to macromolecules are still not well understood. For α-dicarbonyl precursors, such as methylglyoxal and glyoxal, radical reactions through OH-oxidation produce oligomers, irreversibly and faster than accretion reactions. Methyl vinyl ketone (MVK) was chosen in the present study as it is an α, β-unsaturated carbonyl that can undergo such reaction pathways in the aqueous phase and forms even high molecular weight oligomers. We present here experiments on the aqueous phase OH-oxidation of MVK, performed under atmospheric relevant conditions. Using NMR and UV absorption spectroscopy, high and ultra-high resolution mass spectrometry, we show that the fast formation of oligomers up to 1800 Da is due to radical oligomerization of MVK, and 13 series of oligomers (out of a total of 26 series) are identified. The influence of atmospherically relevant parameters such as temperature, initial concentrations of MVK and dissolved oxygen are presented and discussed. In agreement with the experimental observations, we propose a chemical mechanism of OH-oxidation of MVK in the aqueous phase that proceeds via radical oligomerization of MVK on the olefin part of the molecule. This mechanism highlights the paradoxical role of dissolved O2: while it inhibits oligomerization reactions, it contributes to produce oligomerization initiator radicals, which rapidly consume O2, thus leading to the supremacy of oligomerization reactions after several minutes of reaction. These processes, together with the large ranges of initial concentrations investigated (60–656 μM of dissolved O2 and 0.2–20 mM of MVK) show the fundamental role that O2 likely plays in atmospheric organic aerosol.

Development of DNPH/HPLC method for the measurement of carbonyl compounds in the aqueous phase: applications to laboratory simulation and field measurement

2009 ◽  
Vol 6 (5) ◽  
pp. 389 ◽  
Author(s):  
Hongli Wang ◽  
Xuan Zhang ◽  
Zhongming Chen
Keyword(s):  
Aqueous Phase ◽  
Carbonyl Compounds ◽  
Global Climate ◽  
Water Solution ◽  
Field Measurements ◽  
Hplc Method ◽  
Vinyl Ketone ◽  
Methyl Vinyl Ketone ◽  
Laboratory Simulation ◽  
Methyl Vinyl

Environmental context. Carbonyl compounds, a class of oxygenated organic matter, are crucial participants in atmospheric processes. Recently, studies have shown that the aqueous-phase processes of carbonyls have an important contribution to the formation of secondary organic aerosol (SOA), which is considered to have a significant impact on global climate change and human health. We developed the classical DNPH/HPLC method to characterise the aqueous-phase carbonyls, especially methacrolein, methyl vinyl ketone, glyoxal, and methylglyoxal, which are important precursors of SOA, in order to better understand the pathways of SOA formation in the atmosphere. Abstract. The DNPH/HPLC method for characterising monocarbonyls and dicarbonyls in the aqueous phase has been developed. A series of experiments have been carried out using eight atmospheric ubiquitous carbonyl compounds as model dissolved compounds in both acetonitrile and water solution to obtain the optimal derivatisation and analysis qualifications. Compared with the analysis of carbonyls dissolved in acetonitrile, the influence of acidity on the derivatisation efficiency should be carefully considered in determining carbonyls in water and the optimal acidity is pH 2.0. We find that methyl vinyl ketone (MVK) transforms to crotonaldehyde during the derivatisation reaction. This transformation can be controlled to a minor degree by increasing the mixing ratio of DNPH to MVK up to 100 : 1. This improved method has been satisfactorily applied to laboratory simulations and field measurements for better understanding the carbonyl chemistry in the atmosphere.

scholarly journals Isoprene and its oxidation products, methyl vinyl ketone and methacrolein, in the rural troposphere

1993 ◽  
Vol 98 (D1) ◽  
pp. 1101-1111 ◽  
Author(s):  
S. A. Montzka ◽  
M. Trainer ◽  
P. D. Goldan ◽  
W. C. Kuster ◽  
F. C. Fehsenfeld
Keyword(s):  
Vinyl Ketone ◽  
Methyl Vinyl Ketone ◽  
Oxidation Products ◽  
Methyl Vinyl

Isoprene and its oxidation products: Methacrolein and methyl vinyl ketone

1990 ◽  
Vol 95 (D2) ◽  
pp. 1871 ◽  
Author(s):  
David Pierotti ◽  
S. C. Wofsy ◽  
D. Jacob ◽  
R. A. Rasmussen
Keyword(s):  
Vinyl Ketone ◽  
Methyl Vinyl Ketone ◽  
Oxidation Products ◽  
Methyl Vinyl

scholarly journals Gas–particle partitioning of polyol tracers at a suburban site in Nanjing, east China: increased partitioning to the particle phase

2021 ◽  
Vol 21 (15) ◽  
pp. 12141-12153
Author(s):  
Chao Qin ◽  
Yafeng Gou ◽  
Yuhang Wang ◽  
Yuhao Mao ◽  
Hong Liao ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Organic Aerosols ◽  
Water Soluble ◽  
Oxidation Products ◽  
East China ◽  
Particle Phase ◽  
Isoprene Oxidation ◽  
Predicted Values ◽  
Suburban Site ◽  
Isoprene Oxidation Products

Abstract. Gas–particle partitioning of water-soluble organic compounds plays a significant role in influencing the formation, transport, and lifetime of organic aerosols in the atmosphere, but is poorly characterized. In this work, gas- and particle-phase concentrations of isoprene oxidation products (C5-alkene triols and 2-methylterols), levoglucosan, and sugar polyols were measured simultaneously at a suburban site of the western Yangtze River Delta in east China. All target polyols were primarily distributed into the particle phase (85.9 %–99.8 %). Given the uncertainties in measurements and vapor pressure predictions, a dependence of particle-phase fractions on vapor pressures cannot be determined. To explore the impact of aerosol liquid water on gas–particle partitioning of polyol tracers, three partitioning schemes (Cases 1–3) were proposed based on equilibriums of gas vs. organic and aqueous phases in aerosols. If particulate organic matter (OM) is presumed as the only absorbing phase (Case 1), the measurement-based absorptive partitioning coefficients (Kp,OMm) of isoprene oxidation products and levoglucosan were more than 10 times greater than predicted values (Kp,OMt). The agreement between Kp,OMm and Kp,OMt was substantially improved when solubility in a separate aqueous phase was included, whenever water-soluble and water-insoluble OM partitioned into separate (Case 2) or single (Case 3) liquid phases, suggesting that the partitioning of polyol tracers into the aqueous phase in aerosols should not be ignored. The measurement-based effective Henry's law coefficients (KH,em) of polyol tracers were orders of magnitude higher than their predicted values in pure water (KH,wt). Due to the moderate correlations between log⁡(KH,em/KH,wt) and molality of sulfate ions, the gap between KH,em and KH,wt of polyol tracers could not be fully parameterized by the equation defining “salting-in” effects and might be ascribed to mechanisms of reactive uptake, aqueous phase reaction, “like-dissolves-like” principle, etc. These study results also partly reveal the discrepancy between observation and modeling of organic aerosols.

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