Reduction of the Oxides of Nitrogen to Ammonia Stability of Nitric Oxide

1919 ◽  
Vol 87 (2249supp) ◽  
pp. 91-91
Keyword(s):  
Nitric Oxide ◽  
Oxides Of Nitrogen

THE Hg 6(3P1)-PHOTOSENSITIZED DECOMPOSITION OF NITRIC OXIDE

1961 ◽  
Vol 39 (12) ◽  
pp. 2549-2555 ◽  
Author(s):  
Otto P. Strausz ◽  
Harry E. Gunning
Keyword(s):  
Nitric Oxide ◽  
Quantum Yield ◽  
Ground State ◽  
Pressure Range ◽  
Oxides Of Nitrogen ◽  
Total Rate ◽  
A Value ◽  
Electronically Excited ◽  
Static Conditions ◽  
Observed Behavior

The reaction of NO with Hg 6(3P1) atoms has been studied under static conditions at 30°, over the pressure range 1–286 mm. The products were found to be N2, N2O, and higher oxides of nitrogen. At NO pressures exceeding 4 mm, the total rate of formation of N2+N2O was constant, while the ratio N2O/N2 increased linearly with the substrate pressure. The rate was found to vary directly with the first power of the intensity at 2537 Å, and a value of 1.9 × 10−3 moles/einstein was established for the quantum yield of N2 + N2O production. In the proposed mechanism, reaction is attributed to the decomposition of an energy-rich dimer, (NO)2*, which is formed by the collision of electronically excited (4II) NO molecules with those in the ground state. The (NO)2* species is assumed to decompose by the steps: (NO)2* → N2 + O2 and (NO)2* + NO → N2O + NO2. The mechanism satisfactorily explains the observed behavior of the system.

scholarly journals A study of the chemical quality of ambient air at selected intersections in the Durban Metropolis

2003 ◽  
Author(s):  
◽  
Shalini Singh
Keyword(s):  
Nitric Oxide ◽  
Air Pollution ◽  
Nitrogen Dioxide ◽  
Ambient Air ◽  
Urban Environments ◽  
Motor Vehicles ◽  
Chemical Quality ◽  
Oxides Of Nitrogen ◽  
Combustion Processes

Motor vehicles are considered a major source of air pollution in urban environments. Nitrogen dioxide (N02) and nitric oxide (NO) which are collectively referred to as oxides of nitrogen (NOx) are formed at high temperatures during combustion processes in the engines of motor vehicles and are emitted via the exhaust into the atmosphere. Nitrogen dioxide is regarded as an irritant of the respiratory system.

scholarly journals Comment on “Isotopic evidence for dominant secondary production of HONO in near-ground wildfire plumes.”

2021 ◽  
Author(s):  
James Roberts
Keyword(s):  
Nitric Oxide ◽  
Secondary Production ◽  
Nitrous Acid ◽  
Nitrogen Compound ◽  
Decomposition Reaction ◽  
Organic Radicals ◽  
Organic Nitrates ◽  
Oxides Of Nitrogen ◽  
Wild Fire ◽  
Model Reactions

Abstract. Chai et al. recently published measurements of wild fire (WF) derived oxides of nitrogen (NOx) and nitrous acid (HONO) and their isotopic composition. The method used to sample NOx, collection in alkaline solution, has a known 1:1 interference from another reactive nitrogen compound, acetyl peroxynitrate (PAN). Although PAN is thermally unstable, subsequent reactions with nitrogen dioxide (NO2) in effect extend the lifetime of PAN many times longer than the initial decomposition reaction would indicate. This, coupled with the rapid and efficient formation of PAN in WF plumes, means the NOx measurements reported by Chai et al. were severely impacted by PAN. In addition, the model reactions in the original paper did not include the reactions of NO2 with hydroxyl radical (OH) to form nitric acid, nor the efficient reaction of larger organic radicals with nitric oxide to form organic nitrates (RONO2).

scholarly journals Study on the Pollution Characteristics and Sources of Ozone in Typical Loess Plateau City

Atmosphere ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 555
Author(s):  
Bin Li ◽  
Zhuangzhi Zhou ◽  
Zhigang Xue ◽  
Peng Wei ◽  
Yanjun Ren ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Loess Plateau ◽  
Ground Level ◽  
Photochemical Reactions ◽  
Oxides Of Nitrogen ◽  
Ozone Pollution ◽  
Pollution Characteristics ◽  
Nitric Oxide Concentration ◽  
Standard Value ◽  
High Level

Ground-level ozone is a secondary pollutant produced by photochemical reactions and it adversely affects plant and human health. Taiyuan City, a typical city on the loess plateau, is suffering from severe ozone pollution. We utilized the data from eight national environmental monitoring sites of Taiyuan, including concentrations of O3 and nitric oxide, and meteorological factors, such as air temperature and wind, to study the pollution characteristics and sources of ozone (O3) in Taiyuan in 2018. Results show that during 2018, the maximum value and 90th percentile of the maximum 8-h running average of O3 concentration were 257 μg/m3 and 192 μg/m3, respectively. There were 72 days where the O3 concentration exceeded the standard in 2018, which were mainly during April to August. The O3 concentration increased from March, reached a high level in April through August, and decreased significantly from September. The O3 concentrations displayed a typical “single peak” diurnal variation, which was high during the day with peak at around 13:00–15:00 and low at night. From April to August, the O3 concentrations at Jinyuan was the highest, followed by Xiaodian and Taoyuan, and the O3 concentrations at Shanglan and Nanzhai were the lowest. When the O3 concentration exceeded the standard value, Jinyuan contributed the most to the O3 pollution of Taiyuan, followed by Taoyuan and Xiaodian. High temperature and pressure, south and southwest winds can lead to an increase in O3 concentration. The O3 pollution in the Taiyuan urban area is caused by local generation, and the transportation of polluted air masses containing oxides of nitrogen (NOx) and volatile organic compounds (VOCs) emitted by industries, such as the coking and steel plants in counties of Jinzhong City in southern Taiyuan, and Qingxu County, and some counties in Lyuliang City to the southwest. In addition, the mountain winds and low nitric oxide concentration are the main reasons for the increase of O3 concentration, often observed in Shanglan at night.

scholarly journals Effect of Storage on Levels of Nitric Oxide Derivatives in Blood Components.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2884-2884
Author(s):  
Fabiola G. Rizzatti ◽  
David Stroncek ◽  
Melissa Qazi ◽  
Nathawut Sibmooh ◽  
Barbora Piknova ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Red Blood Cells ◽  
Whole Blood ◽  
Blood Cells ◽  
Vascular System ◽  
Oxides Of Nitrogen ◽  
Blood Components ◽  
Transfusion Therapy ◽  
Hypoxic Conditions ◽  
Nitric Oxide Metabolites

Abstract The important role of erythrocytes in nitric oxide (NO) physiology changed the traditional view of the red blood cells (RBC) as only a carrier of oxygen and carbon monoxide. Nitrite is a primary oxidative NO metabolite and is considered a major intravascular storage pool for NO. In the vascular system, erythrocytes are the major storage sites of nitrite, which can be activated to NO by deoxyhemoglobin, but also are responsible for its rapid destruction after reaction with oxyhemoglobin.The purpose of this study was to quantify the nitric oxide metabolites, nitrite and nitrate, in red blood cells (RBCs) stored as packed cells or whole blood and to evaluate their levels with the time of storage. Whole blood, leukoreduced, and non-leukoreduced packed RBCs were obtained from healthy volunteer donors and were stored in polyvinyl chloride (PVC) bags to up to 42 days at 4°C. Sequential aliquots were taken from the bags using a liquid transfer set to maintain sterile conditions. Nitrite and nitrate were measured in the whole blood and in RBC components using reductive gas phase chemiluminescence. Nitrite concentrations decreased during the storage in the three blood components analyzed. The nitrite concentration in RBCs before storage was 202±45 nM, but fell rapidly upon storage. In the leukoreduced RBCs, nitrite levels were 81±36 nM on day 1 and 51±8 nM on day 42. The concentration of nitrate remained stable during blood storage, 30±14 uM on day 1 and 33±5 uM on day 42 of storage. The pH decreased slightly in all three blood components during storage, from pH 6.7±0.05 on day 1 to 6.5±0 on day 42. The blood pO2 before storage was 40.5±1.5 and increased to 251±4 mmHg on day 42, presumably due to the diffusion of oxygen from the room air. In control experiments, PVC bags were filled with normal saline used for medical purposes and stored up to 42 days at 4°C in room air; nitrite concentrations gradually increased while nitrate values remained stable. Similar results were observed for nitrite and nitrate concentrations in the non-leukoreduced RBCs and whole blood. Both cells and saline controls maintained in an argon chamber at 4°C for 42 days showed decreased levels of nitrite when compared to the bags stored in room air under the same temperature. Our results show that nitrite levels fall in hemocomponents during blood bank storage, nitrate remains stable, while pH decreases and pO2 increases. The decrease in nitrite levels could be explained either by its reaction with oxyhemoglobin, resulting in nitrate and methemoglobin, or with deoxyhemoglobin. The diffusion of oxides of nitrogen gases through the PVC bags could in part explain why nitrite levels do not completely disappear in the RBCs stored for transfusion, under standard transfusion medicine conditions. As erythrocytes may contribute to the control of blood flow and oxygen delivery through reduction of nitrite to NO under hypoxic conditions, our findings may provide insight into the vasodynamic effects of blood transfusion. These measurements of NO derivatives may have implication for transfusion therapy, explaining some adverse effects of RBC transfusion and/or optimizing the preservation of stored hemocomponents.

Kinetics of the gas-phase oxidation of methanol catalysed by nitric oxide

1964 ◽  
Vol 17 (2) ◽  
pp. 172 ◽  
Author(s):  
JJ Batten
Keyword(s):  
Nitric Oxide ◽  
Pressure Change ◽  
Product Distribution ◽  
Published Data ◽  
Static System ◽  
Oxides Of Nitrogen ◽  
Kcal Mole ◽  
Oxidation Of Methanol ◽  
Gas Phase Oxidation ◽  
Kinetics Of

The oxidation of methanol catalysed by nitric oxide has been studied in a static system in the temperature range 300-400°. The kinetics and product distribution were compared with previously published data on the uncatalysed reaction and shoum to dlffer significantly. The reaction vessel was of Pyrex glass and the maximum rate was found to be sensitive to the condition of its surface. The rate of pressure change was shown to be a valid measure of the reaction rate which accelerated rapidly to a maximum, remained constant for some time, and then decreased slowly. The overall activation energy was about 8 kcal mole-1 in the range 300-330°, and 25 kcal mole-1 between 360 and 400°. At 310° (d(Δp)/dt)max. ∝ [CH3OH]00.4[O2]0-1 [NO]01.7 and at 380° (d(Δp)/dt)max. ∝ [CH3OH]00.75[O2]0-1 [NO]00.75 provided that [O2]0 < [CH3OH]0 = 100 mmHg. At [O2]0 > [CH3OH]0, the maxi- mum rates were approximately independent of [O2]0 The pressure of the product, formaldehyde, always rose to a maximum and then decayed in the later stages of an experiment. Oxides of nitrogen appear to participate in the chain reaction.

scholarly journals Comment on “Isotopic evidence for dominant secondary production of HONO in near-ground wildfire plumes” by Chai et al. (2021)

2021 ◽  
Vol 21 (22) ◽  
pp. 16793-16795
Author(s):  
James M. Roberts
Keyword(s):  
Nitric Oxide ◽  
Nitric Acid ◽  
Secondary Production ◽  
Nitrous Acid ◽  
Nitrogen Compound ◽  
Decomposition Reaction ◽  
Organic Radicals ◽  
Organic Nitrates ◽  
Oxides Of Nitrogen ◽  
Model Reactions

Abstract. Chai et al. (2021) recently published measurements of wildfire-derived (WF) oxides of nitrogen (NOx) and nitrous acid (HONO) and their isotopic composition. The method used to sample NOx, collection in alkaline solution, has a known 1:1 interference from another reactive nitrogen compound, acetyl peroxynitrate (PAN). Although PAN is thermally unstable, subsequent reactions with nitrogen dioxide (NO2) in effect extend the lifetime of PAN many times longer than the initial decomposition reaction would indicate. This, coupled with the rapid and efficient formation of PAN in WF plumes, means the NOx measurements reported by Chai et al.​​​​​​​ were severely impacted by PAN. In addition, the model reactions in the original paper included neither the reactions of NO2 with hydroxyl radical (OH) to form nitric acid nor the efficient reaction of larger organic radicals with nitric oxide to form organic nitrates (RONO2).

scholarly journals Reduction of Nitrogen Oxides From Gas Turbines by Steam Injection

1971 ◽  
Author(s):  
N. R. Dibelius ◽  
M. B. Hilt ◽  
R. H. Johnson
Keyword(s):  
Nitric Oxide ◽  
Nitrogen Oxides ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Air Flow ◽  
Steam Injection ◽  
Steam Flow ◽  
Oxides Of Nitrogen ◽  
Gas Turbine Combustors

This paper describes the results of tests to determine the effects of steam injection on the production of nitric oxide in gas turbine combustors. When the steam injected into the compressor discharge was 2 percent of the total air flow, the oxides of nitrogen were reduced to 50 percent of what they were with no steam injection for a given load in a gas fired machine. When the steam flow was increased to 4 percent the oxides of nitrogen dropped to 25 percent of the value with no steam.

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