An electron paramagnetic resonance study of nitrogen dioxide dissolved in water, carbon tetrachloride and some organic compounds

Mendiara, S. N.; Sagedahl, A.; Perissinotti, L. J.

doi:10.1007/bf03162326

Cited by 9 publications

(8 citation statements)

References 25 publications

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“…In the following scheme, it is possible to observe the hydrolysis reaction of nitrogen dioxide and the dissociation equilibrium of dinitrogen tetraoxide, which were thoroughly studied and investigated [8,9] Therefore, in this work, the focus was placed in the nitrogen dioxide because it is a primary gas emitted from the vehicular sources, and participates in several reactions in the atmosphere.…”

Section: Resultsmentioning

confidence: 99%

NO₂ measurements at the bus station area in a big tourist city in Argentina

Mendiara¹,

Sagedahl²,

García³

et al. 2006

WIT Transactions on Ecology and the Environment, Vol 86

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Ambient air concentrations of Nitrogen dioxide (NO 2 ) were monitored, together with the main meteorological parameters, at Mar del Plata's bus station. This city is located in the southeast of Buenos Aires province, in Argentina, and by the sea. Nitrogen dioxide was selected because its effects on health are particularly critical and it is considered a hazardous substance.The standard sample analysis method for nitrogen dioxide was used, which is under the jurisdiction of ASTM committee (ASTM Designation: D 1607-76(1), 1979), based on the Griess-Saltzman reaction, and the IRAM 29268 (Argentina norm). Sampling was carried out in a fritted-tip bubbler. The absorbing device was installed at the places where people wait for the buses and at approximately 60 cm from the floor.The concentrations measured were considerably higher than those corresponding to other urban sites. However, the resulting NO 2 levels were always below the existing air quality standards. Moreover, the results obtained may alert and guide the development of future controls and may be applied in the evaluation of air quality models. It is also an important step towards improving the knowledge of driver and passenger exposure in the urban area.

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Section: Resultsmentioning

confidence: 99%

NO₂ measurements at the bus station area in a big tourist city in Argentina

Mendiara¹,

Sagedahl²,

García³

et al. 2006

WIT Transactions on Ecology and the Environment, Vol 86

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“…Some authors had interpreted them as the spectrum of NO [11]. However, it was confirmed that those UV-vis spectra were obtained in polar solvents and could be attributed to the formation of HNO 2 [1,12].…”

Section: β-Carotene and Free Radical Reactions With Nitrogen Oxidesmentioning

confidence: 93%

“…The signal is not resolved, due to the movement of the free radical and to the collisions that usually take place at the working temperature. Noticed that our research was always carried out under argon atmosphere [1,9].…”

Section: β-Carotene and Free Radical Reactions With Nitrogen Oxidesmentioning

confidence: 99%

β‐Carotene and Free Radical Reactions with Nitrogen Oxides

Mendiara¹,

Perissinotti²

2017

Carotenoids

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The following presentation is based on experimental work we have already developed and published. We investigated the nitrogen oxides in different solvents and analyzed their reaction with β-carotene. The electron paramagnetic resonance spectroscopy (EPR) and ultraviolet and visible (UV-vis) spectroscopy were applied to investigate the reaction of β-carotene with nitrogen dioxide and nitric oxide in both pure dioxane and dioxane/ water solvent. Free radicals were detected and evaluated with the EPR technique, which is highly selective and sensitive. A reaction mechanism was proposed on the basis of the experimental kinetic and EPR results. The validity of the mechanism was checked by applying simulation set up conditions that reproduced the results achieved. The radical intermediates proposed in the reaction: the β-carotene neutral radicals and the cyclic nitroxide neutral radicals were theoretically studied. For that purpose, the density functional theory (DFT) level was applied, selecting the most suitable method, the unrestricted Becke-style 3-parameter with the Lee-Yang-Parr correlation functional (UB3LYP) and the 6-31G(d) basis sets (d orbital functions). We developed an appropriate discussion on the importance of carotenoids compounds and their reactions in biological media. Also, we evaluated the role and the possible reactions of nitroxide intermediates.

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“…mol-~) is intermediate between that of a typical covalently bound molecule anda van der Waals complex [1]. We have gathered extensive gas-phase equilibrium data [24]. Nowadays interest persists, particularly, at the educational level, because this equilibrium is readily shifted upon changes in the temperature, pressure or volume of the gaseous mixture [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

“…We have already carried out and analyzed electron paramagnetic resonance (EPR) spectra of N204-NO 2 in different solvents [24]. In the present paper we report the measurement of equilibrium constants, enthalpies and other thermodynamic properties for the dissociation in hexane, carbon tetrachloride and chloroform.…”

Section: Introductionmentioning

confidence: 99%

Dissociation equilibrium of dinitrogen tetroxide in organic solvents: An electron paramagnetic resonance measurement

Mendiara

Perissinotti

2003

Appl. Magn. Reson.

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The dissociation equilibrium of N204-NO 2 has been measured in hexane, carbon tetrachloride and chloroform at different temperatures. The equilibrium constants at 298.15 K (25~ K,, (molality basis), are 3.5.10 -~ in hexane, 5.9-10 -6 in carbon tetrachloride and 5.3 9 l0 -6 in chloroform. The EPR technique has been used to quantify the NO_, radical. These data are compared with gas-phase and solution data of previous reports. The applicability of Hildebrand and Scatchard theory of solutions is also discussed and some thermodynamic properties are deduced, such as Henry's N204 and NO 2 constants in different solvents.

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An electron paramagnetic resonance study of nitrogen dioxide dissolved in water, carbon tetrachloride and some organic compounds

Cited by 9 publications

References 25 publications

NO₂ measurements at the bus station area in a big tourist city in Argentina

NO₂ measurements at the bus station area in a big tourist city in Argentina

β‐Carotene and Free Radical Reactions with Nitrogen Oxides

Dissociation equilibrium of dinitrogen tetroxide in organic solvents: An electron paramagnetic resonance measurement

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An electron paramagnetic resonance study of nitrogen dioxide dissolved in water, carbon tetrachloride and some organic compounds

Cited by 9 publications

References 25 publications

NO2 measurements at the bus station area in a big tourist city in Argentina

NO2 measurements at the bus station area in a big tourist city in Argentina

β‐Carotene and Free Radical Reactions with Nitrogen Oxides

Dissociation equilibrium of dinitrogen tetroxide in organic solvents: An electron paramagnetic resonance measurement

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Product

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NO₂ measurements at the bus station area in a big tourist city in Argentina

NO₂ measurements at the bus station area in a big tourist city in Argentina