Effect of the structure of methyl-substituted carboxylic acids and anhydrides on their activity in gas-phase oxidation

1982 ◽  
Vol 31 (4) ◽  
pp. 817-820
Author(s):  
A. Kh. Sharipov ◽  
R. M. Masagutov ◽  
S. R. Rafikov
Keyword(s):  
Gas Phase ◽  
Carboxylic Acids ◽  
Phase Oxidation ◽  
Gas Phase Oxidation

scholarly journals α-pinene photooxidation under controlled chemical conditions – Part 2: SOA yield and composition in low- and high-NOx environments

2012 ◽  
Vol 12 (4) ◽  
pp. 8579-8615
Author(s):  
N. C. Eddingsaas ◽  
C. L. Loza ◽  
L. D. Yee ◽  
M. Chan ◽  
K. A. Schilling ◽  
...  
Keyword(s):  
Gas Phase ◽  
Ammonium Sulfate ◽  
Carboxylic Acids ◽  
Peroxy Radical ◽  
Organic Aerosol ◽  
Seed Particles ◽  
Field Samples ◽  
Phase Oxidation ◽  
Gas Phase Oxidation ◽  
Chemical Conditions

Abstract. The gas-phase oxidation of α-pinene produces a large amount of secondary organic aerosol (SOA) in the atmosphere. A number of carboxylic acids, organosulfates and nitrooxy organosulfates associated with α-pinene have been found in field samples and some are used as tracers of α-pinene oxidation. α-pinene reacts readily with OH and O3 in the atmosphere followed by reactions with both HO2 and NO. Due to the large number of potential reaction pathways, it can be difficult to determine what conditions lead to SOA. To better understand the SOA yield and chemical composition from low- and high-NOx OH oxidation of α-pinene, studies were conducted in the Caltech atmospheric chamber under controlled chemical conditions. Experiments used low O3 concentrations to ensure that OH was the main oxidant and low α-pinene concentrations such that the peroxy radical (RO2) reacted primarily with either HO2 under low-NOx conditions or NO under high-NOx conditions. SOA yield was suppressed under conditions of high-NO. SOA yield under high-NO conditions was greater when ammonium sulfate/sulfuric acid seed particles (highly acidic) were present prior to the onset of growth than when ammonium sulfate seed particles (mildly acidic) were present; this dependence was not observed under low-NOx conditions. When aerosol seed particles were introduced after OH oxidation, allowing for later generation species to be exposed to fresh inorganic seed particles, a number of low-NOx products partitioned to the highly acidic aerosol. This indicates that the effect of seed acidity and SOA yield might be under-estimated in traditional experiments where aerosol seed particles are introduced prior to oxidation. We also identify the presence of a number of carboxylic acids that are used as tracer compounds of α-pinene oxidation in the field as well as the formation of organosulfates and nitrooxy organosulfates. A number of the carboxylic acids were observed under all conditions, however, pinic and pinonic acid were only observed under low-NOx conditions. Evidence is provided for particle-phase sulfate esterification of multi-functional alcohols.

scholarly journals α-pinene photooxidation under controlled chemical conditions – Part 2: SOA yield and composition in low- and high-NO<sub>x</sub> environments

2012 ◽  
Vol 12 (16) ◽  
pp. 7413-7427 ◽  
Author(s):  
N. C. Eddingsaas ◽  
C. L. Loza ◽  
L. D. Yee ◽  
M. Chan ◽  
K. A. Schilling ◽  
...  
Keyword(s):  
Gas Phase ◽  
Ammonium Sulfate ◽  
Carboxylic Acids ◽  
Peroxy Radical ◽  
Organic Aerosol ◽  
Seed Particles ◽  
Field Samples ◽  
Phase Oxidation ◽  
Gas Phase Oxidation ◽  
Chemical Conditions

Abstract. The gas-phase oxidation of α-pinene produces a large amount of secondary organic aerosol (SOA) in the atmosphere. A number of carboxylic acids, organosulfates and nitrooxy organosulfates associated with α-pinene have been found in field samples and some are used as tracers of α-pinene oxidation. α-pinene reacts readily with OH and O3 in the atmosphere followed by reactions with both HO2 and NO. Due to the large number of potential reaction pathways, it can be difficult to determine what conditions lead to SOA. To better understand the SOA yield and chemical composition from low- and high-NOx OH oxidation of α-pinene, studies were conducted in the Caltech atmospheric chamber under controlled chemical conditions. Experiments used low O3 concentrations to ensure that OH was the main oxidant and low α-pinene concentrations such that the peroxy radical (RO2) reacted primarily with either HO2 under low-NOx conditions or NO under high-NOx conditions. SOA yield was suppressed under conditions of high-NOx. SOA yield under high-NOx conditions was greater when ammonium sulfate/sulfuric acid seed particles (highly acidic) were present prior to the onset of growth than when ammonium sulfate seed particles (mildly acidic) were present; this dependence was not observed under low-NOx conditions. When aerosol seed particles were introduced after OH oxidation, allowing for later generation species to be exposed to fresh inorganic seed particles, a number of low-NOx products partitioned to the highly acidic aerosol. This indicates that the effect of seed acidity and SOA yield might be under-estimated in traditional experiments where aerosol seed particles are introduced prior to oxidation. We also identify the presence of a number of carboxylic acids that are used as tracer compounds of α-pinene oxidation in the field as well as the formation of organosulfates and nitrooxy organosulfates. A number of the carboxylic acids were observed under all conditions, however, pinic and pinonic acid were only observed under low-NOx conditions. Evidence is provided for particle-phase sulfate esterification of multi-functional alcohols.

Gas phase oxidation of furfural to maleic anhydride on V 2 O 5 /γ-Al 2 O 3 catalysts: Reaction conditions to slow down the deactivation

2017 ◽  
Vol 348 ◽  
pp. 265-275 ◽  
Author(s):  
N. Alonso-Fagúndez ◽  
M. Ojeda ◽  
R. Mariscal ◽  
J.L.G. Fierro ◽  
M. López Granados
Keyword(s):  
Maleic Anhydride ◽  
Gas Phase ◽  
Reaction Conditions ◽  
Phase Oxidation ◽  
Gas Phase Oxidation

scholarly journals Volatility of secondary organic aerosol during OH radical induced ageing

2011 ◽  
Vol 11 (21) ◽  
pp. 11055-11067 ◽  
Author(s):  
K. Salo ◽  
M. Hallquist ◽  
Å. M. Jonsson ◽  
H. Saathoff ◽  
K.-H. Naumann ◽  
...  
Keyword(s):  
Gas Phase ◽  
Organic Aerosol ◽  
Oh Radical ◽  
High Concentration ◽  
Volatile Material ◽  
Phase Oxidation ◽  
Gas Phase Oxidation ◽  
Institute Of Technology ◽  
Set Up ◽  
Pinic Acid

Abstract. The aim of this study was to investigate oxidation of SOA formed from ozonolysis of α-pinene and limonene by hydroxyl radicals. This paper focuses on changes of particle volatility, using a Volatility Tandem DMA (VTDMA) set-up, in order to explain and elucidate the mechanism behind atmospheric ageing of the organic aerosol. The experiments were conducted at the AIDA chamber facility of Karlsruhe Institute of Technology (KIT) in Karlsruhe and at the SAPHIR chamber of Forchungzentrum Jülich (FZJ) in Jülich. A fresh SOA was produced from ozonolysis of α-pinene or limonene and then aged by enhanced OH exposure. As an OH radical source in the AIDA-chamber the ozonolysis of tetramethylethylene (TME) was used while in the SAPHIR-chamber the OH was produced by natural light photochemistry. A general feature is that SOA produced from ozonolysis of α-pinene and limonene initially was rather volatile and becomes less volatile with time in the ozonolysis part of the experiment. Inducing OH chemistry or adding a new portion of precursors made the SOA more volatile due to addition of new semi-volatile material to the aged aerosol. The effect of OH chemistry was less pronounced in high concentration and low temperature experiments when lower relative amounts of semi-volatile material were available in the gas phase. Conclusions drawn from the changes in volatility were confirmed by comparison with the measured and modelled chemical composition of the aerosol phase. Three quantified products from the α-pinene oxidation; pinonic acid, pinic acid and methylbutanetricarboxylic acid (MBTCA) were used to probe the processes influencing aerosol volatility. A major conclusion from the work is that the OH induced ageing can be attributed to gas phase oxidation of products produced in the primary SOA formation process and that there was no indication on significant bulk or surface reactions. The presented results, thus, strongly emphasise the importance of gas phase oxidation of semi- or intermediate-volatile organic compounds (SVOC and IVOC) for atmospheric aerosol ageing.

Experimental and Modeling Study of the Selective Homogeneous Gas Phase Oxidation of Methane to Methanol

1995 ◽  
Vol 34 (4) ◽  
pp. 1044-1059 ◽  
Author(s):  
Rune Lodeng ◽  
Odd A. Lindvaag ◽  
Paal Soraker ◽  
Per T. Roterud ◽  
Olav T. Onsager
Keyword(s):  
Gas Phase ◽  
Oxidation Of Methane ◽  
Phase Oxidation ◽  
Gas Phase Oxidation ◽  
Modeling Study

Effect of Vanadia Doping and Its Oxidation State on the Photocatalytic Activity of TiO2 for Gas-Phase Oxidation of Ethene

2008 ◽  
Vol 112 (48) ◽  
pp. 19102-19112 ◽  
Author(s):  
K. Bhattacharyya ◽  
S. Varma ◽  
A. K. Tripathi ◽  
S. R. Bharadwaj ◽  
A. K. Tyagi
Keyword(s):  
Photocatalytic Activity ◽  
Gas Phase ◽  
Oxidation State ◽  
Phase Oxidation ◽  
Gas Phase Oxidation
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