Experimental and Theoretical Understanding of the Gas Phase Oxidation of Atmospheric Amides with OH Radicals: Kinetics, Products, and Mechanisms

2014 ◽  
Vol 119 (19) ◽  
pp. 4298-4308 ◽  
Author(s):  
Nadine Borduas ◽  
Gabriel da Silva ◽  
Jennifer G. Murphy ◽  
Jonathan P. D. Abbatt
Keyword(s):  
Gas Phase ◽  
Oh Radicals ◽  
Theoretical Understanding ◽  
Phase Oxidation ◽  
Gas Phase Oxidation

Gas-Phase Oxidation of Methyl Crotonate and Ethyl Crotonate. Kinetic Study of Their Reactions toward OH Radicals and Cl Atoms

2012 ◽  
Vol 116 (24) ◽  
pp. 6127-6133 ◽  
Author(s):  
Mariano A. Teruel ◽  
Julio Benitez-Villalba ◽  
Norma Caballero ◽  
María B. Blanco
Keyword(s):  
Kinetic Study ◽  
Gas Phase ◽  
Oh Radicals ◽  
Phase Oxidation ◽  
Gas Phase Oxidation ◽  
Cl Atoms

Gas Phase Oxidation of Nicotine by OH Radicals: Kinetics, Mechanisms, and Formation of HNCO

2016 ◽  
Vol 3 (9) ◽  
pp. 327-331 ◽  
Author(s):  
Nadine Borduas ◽  
Jennifer G. Murphy ◽  
Chen Wang ◽  
Gabriel da Silva ◽  
Jonathan P. D. Abbatt
Keyword(s):  
Gas Phase ◽  
Oh Radicals ◽  
Phase Oxidation ◽  
Gas Phase Oxidation

scholarly journals An isotope view on ionising radiation as a source of sulphuric acid

2012 ◽  
Vol 12 (2) ◽  
pp. 5039-5064 ◽  
Author(s):  
M. B. Enghoff ◽  
N. Bork ◽  
S. Hattori ◽  
C. Meusinger ◽  
M. Nakagawa ◽  
...  
Keyword(s):  
Gas Phase ◽  
Sulphuric Acid ◽  
Gamma Rays ◽  
Uv Light ◽  
Isotope Ratio Mass Spectrometry ◽  
Ionising Radiation ◽  
Oh Radicals ◽  
Phase Oxidation ◽  
Gas Phase Oxidation ◽  
Mass Dependent

Abstract. Sulphuric acid is an important factor in aerosol nucleation and growth. It has been shown that ions enhance the formation of sulphuric acid aerosols, but the exact mechanism has remained undetermined. Furthermore some studies have found a deficiency in the sulphuric acid budget, suggesting a missing source. In this study the production of sulphuric acid from SO2 through a number of different pathways is investigated. The production methods are standard gas phase oxidation by OH radicals produced by ozone photolysis with UV light, liquid phase oxidation by ozone, and gas phase oxidation initiated by gamma rays. The distributions of stable sulphur isotopes in the products and substrate were measured using isotope ratio mass spectrometry. All methods produced sulphate enriched in 34S and we find a δ34S value of 8.7 ± 0.4‰ (1 standard deviation) for the UV-initiated OH reaction. Only UV light (Hg emission at 253.65 nm) produced a clear non-mass-dependent excess of 33S. The pattern of isotopic enrichment produced by gamma rays is similar, but not equal, to that produced by aqueous oxidation of SO2 by ozone. This, combined with the relative yields of the experiments, suggests a mechanism in which ionising radiation may lead to hydrated ion clusters that serve as nanoreactors for S(IV) to S(VI) conversion.

scholarly journals Why do organic aerosols exist? Understanding aerosol lifetimes using the two-dimensional volatility basis set

2013 ◽  
Vol 10 (3) ◽  
pp. 151 ◽  
Author(s):  
N. M. Donahue ◽  
W. Chuang ◽  
S. A. Epstein ◽  
J. H. Kroll ◽  
D. R. Worsnop ◽  
...  
Keyword(s):  
Human Health ◽  
Gas Phase ◽  
Fine Particles ◽  
Critical Role ◽  
Organic Aerosols ◽  
Basis Set ◽  
Oh Radicals ◽  
Phase Oxidation ◽  
Gas Phase Oxidation ◽  
Oxidation Chemistry

Environmental context Fine particles (aerosols) containing organic compounds are central players in two important environmental issues: aerosol-climate effects and human health effects (including mortality). Although organics constitute half or more of the total fine-particle mass, their chemistry is extremely complex; of critical importance is ongoing oxidation chemistry in both the gas phase and the particle phase. Here we present a method for representing that oxidation chemistry when the actual composition of the organics is not known and show that relatively slow oxidant uptake to particles plays a key role in the very existence of organic aerosols. Abstract Organic aerosols play a critical role in atmospheric chemistry, human health and climate. Their behaviour is complex. They consist of thousands of organic molecules in a rich, possibly highly viscous mixture that may or may not be in phase equilibrium with organic vapours. Because the aerosol is a mixture, compounds from all sources interact and thus influence each other. Finally, most ambient organic aerosols are highly oxidised, so the molecules are secondary products formed from primary emissions by oxidation chemistry and possibly non-oxidative association reactions in multiple phases, including gas-phase oxidation, aqueous oxidation, condensed (organic) phase reactions and heterogeneous interactions of all these phases. In spite of this complexity, we can make a strong existential statement about organic aerosol: They exist throughout the troposphere because heterogeneous oxidation by OH radicals is more than an order of magnitude slower than comparable gas-phase oxidation.

scholarly journals Organic peroxide and OH formation in aerosol and cloud water: laboratory evidence for this aqueous chemistry

2015 ◽  
Vol 15 (12) ◽  
pp. 17367-17396 ◽  
Author(s):  
Y. B. Lim ◽  
B. J. Turpin
Keyword(s):  
Gas Phase ◽  
Organic Compounds ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Organic Peroxide ◽  
Oh Radicals ◽  
Organic Peroxides ◽  
Aqueous Chemistry ◽  
Phase Oxidation ◽  
Gas Phase Oxidation

Abstract. Aqueous chemistry in atmospheric waters (e.g., cloud droplets or wet aerosols) is well accepted as an atmospheric pathway to produce secondary organic aerosol (SOAaq). Water-soluble organic compounds with small carbon numbers (C2-C3) are precursors for SOAaq and products include organic acids, organic sulfates, and high molecular weight compounds/oligomers. Fenton reactions and the uptake of gas-phase OH radicals are considered to be the major oxidant sources for aqueous organic chemistry. However, the sources and availability of oxidants in atmospheric waters are not well understood. The degree to which OH is produced in the aqueous phase affects the balance of radical and non-radical aqueous chemistry, the properties of the resulting aerosol, and likely its atmospheric behavior. This paper demonstrates organic peroxide formation during aqueous photooxidation of methylglyoxal using ultra high resolution Fourier Transform Ion Cyclotron Resonance electrospray ionization mass spectrometry (FTICR-MS). Organic peroxides are known to form through gas-phase oxidation of volatile organic compounds. They contribute secondary organic aerosol (SOA) formation directly by forming peroxyhemiacetals, and epoxides, and indirectly by enhancing gas-phase oxidation through OH recycling. We provide simulation results of organic peroxide/peroxyhemiacetal formation in clouds and wet aerosols and discuss organic peroxides as a source of condensed-phase OH radicals and as a contributor to aqueous SOA.

Kinetics, product distribution and atmospheric implications of the gas-phase oxidation of allyl sulfides by OH radicals

Chemosphere ◽  
2021 ◽  
pp. 132546
Author(s):  
Alejandro L. Cardona ◽  
Rodrigo G. Gibilisco ◽  
Cynthia B. Rivela ◽  
María B. Blanco ◽  
Iulia Patroescu-Klotz ◽  
...  
Keyword(s):  
Gas Phase ◽  
Product Distribution ◽  
Oh Radicals ◽  
Phase Oxidation ◽  
Gas Phase Oxidation ◽  
Allyl Sulfides

Effect of NOx on product yields and Arrhenius parameters of gas-phase oxidation of β-ocimene initiated by OH˙ radicals

RSC Advances ◽  
2016 ◽  
Vol 6 (95) ◽  
pp. 92795-92803 ◽  
Author(s):  
Elizabeth Gaona-Colmán ◽  
María B. Blanco ◽  
Ian Barnes ◽  
Mariano A. Teruel
Keyword(s):  
Gas Phase ◽  
Total Pressure ◽  
Addition Product ◽  
Rate Coefficients ◽  
Oh Radicals ◽  
Phase Reaction ◽  
Gas Phase Reaction ◽  
Phase Oxidation ◽  
P Rate ◽  
Gas Phase Oxidation

Rate coefficients for the gas-phase reaction of OH˙ radicals with β-ocimene were measured over the temperature range 288–311 K at 760 Torr total pressure of nitrogen. In addition, product studies have been performed in the absence and presence of NOx.

scholarly journals An isotopic analysis of ionising radiation as a source of sulphuric acid

2012 ◽  
Vol 12 (12) ◽  
pp. 5319-5327 ◽  
Author(s):  
M. B. Enghoff ◽  
N. Bork ◽  
S. Hattori ◽  
C. Meusinger ◽  
M. Nakagawa ◽  
...  
Keyword(s):  
Gas Phase ◽  
Sulphuric Acid ◽  
Gamma Rays ◽  
Uv Light ◽  
Isotope Ratio Mass Spectrometry ◽  
Isotopic Analysis ◽  
Ionising Radiation ◽  
Oh Radicals ◽  
Phase Oxidation ◽  
Gas Phase Oxidation

Abstract. Sulphuric acid is an important factor in aerosol nucleation and growth. It has been shown that ions enhance the formation of sulphuric acid aerosols, but the exact mechanism has remained undetermined. Furthermore some studies have found a deficiency in the sulphuric acid budget, suggesting a missing source. In this study the production of sulphuric acid from SO2 through a number of different pathways is investigated. The production methods are standard gas phase oxidation by OH radicals produced by ozone photolysis with UV light, liquid phase oxidation by ozone, and gas phase oxidation initiated by gamma rays. The distributions of stable sulphur isotopes in the products and substrate were measured using isotope ratio mass spectrometry. All methods produced sulphate enriched in 34S and we find an enrichment factor (δ34S) of 8.7 ± 0.4‰ (1 standard deviation) for the UV-initiated OH reaction. Only UV light (Hg emission at 253.65 nm) produced a clear non-mass-dependent excess of 33S. The pattern of isotopic enrichment produced by gamma rays is similar, but not equal, to that produced by aqueous oxidation of SO2 by ozone. This, combined with the relative yields of the experiments, suggests a mechanism in which ionising radiation may lead to hydrated ion clusters that serve as nanoreactors for S(IV) to S(VI) conversion.

scholarly journals Laboratory evidence of organic peroxide and peroxyhemiacetal formation in the aqueous phase and implications for aqueous OH

2015 ◽  
Vol 15 (22) ◽  
pp. 12867-12877 ◽  
Author(s):  
Y. B. Lim ◽  
B. J. Turpin
Keyword(s):  
Gas Phase ◽  
Organic Compounds ◽  
Aqueous Phase ◽  
Organic Aerosol ◽  
Organic Peroxide ◽  
Oh Radicals ◽  
Organic Peroxides ◽  
Aqueous Chemistry ◽  
Phase Oxidation ◽  
Gas Phase Oxidation

Abstract. Aqueous chemistry in atmospheric waters (e.g., cloud droplets or wet aerosols) is considered a potentially important atmospheric pathway to produce secondary organic aerosol (SOAaq). Water-soluble organic compounds with small carbon numbers (C2–C3) are precursors for SOAaq; products include organic acids, organic sulfates, and high-molecular-weight compounds/oligomers. Fenton reactions and the uptake of gas-phase OH radicals are considered to be the major oxidant sources for aqueous organic chemistry. However, the sources and availability of oxidants in atmospheric waters are not well understood. The degree to which OH is produced in the aqueous phase affects the balance of radical and non-radical aqueous chemistry, the properties of the resulting aerosol, and likely its atmospheric behavior. This paper demonstrates organic peroxide formation during aqueous photooxidation of methylglyoxal using ultra-high-resolution Fourier transform ion cyclotron resonance electrospray ionization mass spectrometry (FTICR-MS). Organic peroxides are known to form through gas-phase oxidation of volatile organic compounds. They contribute secondary organic aerosol (SOA) formation directly by forming peroxyhemiacetals and epoxides (i.e., IEPOX), and indirectly by enhancing gas-phase oxidation through OH recycling. We provide simulation results of organic peroxide/peroxyhemiacetal formation in clouds and wet aerosols and discuss organic peroxides as a source of condensed-phase OH radicals and as a contributor to aqueous SOA.

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