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

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.

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

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 Seasonal Variation of Biogenic and Anthropogenic VOCs in a Semi-Urban Area Near Sydney, Australia

Atmosphere ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 47
Author(s):  
Jhonathan Ramirez-Gamboa ◽  
Clare Paton-Walsh ◽  
Ian Galbally ◽  
Jack Simmons ◽  
Elise-Andree Guerette ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Urban Area ◽  
Southern Hemisphere ◽  
Seasonal Changes ◽  
Vinyl Ketone ◽  
Methyl Vinyl Ketone ◽  
Oxidation Products ◽  
Atmospheric Composition ◽  
Methyl Vinyl ◽  
Sydney Australia

Volatile organic compounds (VOCs) play a key role in the formation of ozone and secondary organic aerosol, the two most important air pollutants in Sydney, Australia. Despite their importance, there are few available VOC measurements in the area. In this paper, we discuss continuous GC-MS measurements of 10 selected VOCs between February (summer in the southern hemisphere) and June (winter in the southern hemisphere) of 2019 in a semi-urban area between natural eucalypt forest and the Sydney metropolitan fringe. Combined, isoprene, methacrolein, methyl-vinyl-ketone, α-pinene, p-cymene, eucalyptol, benzene, toluene xylene and tri-methylbenzene provide a reasonable representation of variability in the total biogenic VOC (BVOC) and anthropogenic VOC (AVOC) loading in the area. Seasonal changes in environmental conditions were reflected in observed BVOC concentrations, with a summer peak of 8 ppb, dropping to approximately 0.1 ppb in winter. Isoprene, and its immediate oxidation products methacrolein (MACR) and methyl-vinyl-ketone (MVK), dominated BVOC concentrations during summer and early autumn, while monoterpenes comprised the larger fraction during winter. Temperature and solar radiation drive most of the seasonal variation observed in BVOCs. Observed levels of isoprene, MACR and MVK in the atmosphere are closely related with variations in temperature and photosynthetically active radiation (PAR), but chemistry and meteorology may play a more important role for the monoterpenes. Using a nonlinear model, temperature explains 51% and PAR 38% of the isoprene, MACR and MVK variation. Eucalyptol dominated the observed monoterpene fraction (contributing ~75%), with p-cymene (20%) and α-pinene (5%) also present. AVOCs maintain an average concentration of ~0.4 ppb, with a slight decrease during autumn–winter. The low AVOC concentrations observed indicate a relatively small anthropogenic influence, generally occurring when (rare) northerly winds transport Sydney emissions to the measurement site. The site is influenced by domestic, commercial and vehicle AVOC emissions. Our observed AVOC concentrations can be explained by the seasonal changes in meteorology and the emissions in the area as listed in the NSW emissions inventory and thereby act as an independent validation of this inventory. We conclude that the variations in atmospheric composition observed during the seasons are an important variable to consider when formulating air pollution control policies over Sydney given the influence of biogenic sources during summer, autumn and winter.

Oxidation of Poly(Isoprene)

1974 ◽  
Vol 47 (5) ◽  
pp. 1094-1115 ◽  
Author(s):  
J. L. Morand
Keyword(s):  
Prussian Blue ◽  
Experimental Work ◽  
Early Stage ◽  
Colorimetric Method ◽  
Vinyl Ketone ◽  
Methyl Vinyl Ketone ◽  
Oxidation Products ◽  
Methyl Vinyl ◽  
Volatile Oxidation Products ◽  
Conjugated Polyenes

Abstract A Prussian Blue colorimetric method has been developed to determine the number of conjugated polyenes present in commercial elastomers. These groups disappear at the onset of oxidation of unvulcanized lithium-poly (isoprene) : their content decreases by about 50 per cent during the first hour heating at 100° C in air. Simultaneously, a great number of volatile oxidation products are formed since the early stage of aging. The major products, the concentrations of which increase throughout heating until oxidation is advanced, are presumably produced by random attack on the regular isoprene units. The present investigation has made it possible to isolate from this group of compounds 4-methyl-4-vinyl-butyrolactone and 4-hydroxy-2-butanone, previously unrecognized, in addition to levulinaldehyde, methacrolein, and methyl vinyl ketone previously identified by Bevilacqua. An attempt was made to explain their origin. In addition to the compounds just mentioned, minor products corresponding essentially to unsaturated aldehydes and esters were also obtained. They might arise from the decomposition of conjugated polyenes which disappear at the start of oxidation. They have not yet been collected in sufficient amounts to confirm their structures and more experimental work is required to establish the mechanism by which they are formed.

scholarly journals Technical note: Conversion of isoprene hydroxy hydroperoxides (ISOPOOHs) on metal environmental simulation chamber walls

2017 ◽  
Vol 17 (6) ◽  
pp. 4053-4062 ◽  
Author(s):  
Anne-Kathrin Bernhammer ◽  
Martin Breitenlechner ◽  
Frank N. Keutsch ◽  
Armin Hansel
Keyword(s):  
Gas Phase ◽  
Technical Note ◽  
Vinyl Ketone ◽  
Heterogeneous Reactions ◽  
Methyl Vinyl Ketone ◽  
Oxidation Products ◽  
Chemical Mechanism ◽  
Stainless Steel Surface ◽  
Methyl Vinyl

Abstract. Sources and sinks of isoprene oxidation products from low-NOx isoprene chemistry have been studied at the CERN CLOUD (Cosmics Leaving Outdoor Droplets) chamber with a custom-built selective reagent ion time-of-flight mass spectrometer (SRI-ToF-MS), which allows quantitative measurement of isoprene hydroxy hydroperoxides (ISOPOOHs). The measured concentrations of the main oxidation products were compared to chemical box model simulations based on the Leeds Master Chemical Mechanism (MCM) v3.3. The modeled ISOPOOH concentrations are a factor of 20 higher than the observed concentrations, and methyl vinyl ketone (MVK) and methacrolein (MACR) concentrations are up to a factor of 2 lower compared to observations, despite the artifact-free detection method. Addition of catalytic conversion of 1,2-ISOPOOH and 4,3-ISOPOOH to methyl vinyl ketone (MVK) and methacrolein (MACR) on the stainless-steel surface of the chamber to the chemical mechanism resolves the discrepancy between model predictions and observation. This suggests that isoprene chemistry in a metal chamber under low-NOx conditions cannot be described by a pure gas phase model alone. Biases in the measurement of ISOPOOH, MVK, and MACR can be caused not only intra-instrumentally but also by the general experimental setup. The work described here extends the role of heterogeneous reactions affecting gas phase composition and properties from instrumental surfaces, described previously, to general experimental setups. The role of such conversion reactions on real environmental surfaces is yet to be explored.

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