Temperature and Ionic Strength Dependence of NO3-radical Reactions with Substituted Phenols in Aqueous Solution
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C. Weller
Abstract
NO3 oxidation reactions contribute to the chemical conversion processes of organic compounds in the tropospheric multiphase system. Substituted phenols are known pollutants in cloud droplets, rain, fog and (deliquescent) particles. This study presents rate constants obtained from kinetic investigations of NO3 reactions with different substituted phenolic compounds in the aqueous solution. Effects of the temperature as well as the ionic strength on the reaction rates were measured using a laser flash photolysis – laser long path absorption (LP-LLPA) set-up. The following rate constants at T = 298 K in M-1s-1 were obtained for reactions of the NO3 radical with 4-nitrophenol (k = (8.8±4.6) · 108), 2-nitrophenol (k = (8.3±1.4) · 108), 4-hydroxybenzoic acid (k = (1.5±0.4) · 109), 4-methylphenol (k = (1.7±0.3) · 109), 4-methoxyphenol (k = (2.5±0.4) · 109), 4-aminophenol (k = (2.0±0.3) · 109), 2,6-dichlorophenol (k = (1.3±0.2) · 109), 2,6-dihydroxyphenol (k = (1.7±0.2) · 109), 2,6-dimethylphenol (k = (1.8±0.3) · 109), 2,6-dimethoxyphenol (k = (1.6±0.4) · 109), 2,6-dinitrophenol (k = (2.8±0.9) · 108), 4-hydroxy-3,5-dimethoxybenzaldehyde (k = (1.7±0.3) · 109), 4-hydroxy-3,5-dimethoxybenzoic acid (k = (1.4±0.6) · 109), 4-hydroxy-3-methoxybenzaldehyde (k = (1.1±0.2) · 109), 4-hydroxy-3-methoxybenzoic acid (k = (1.0±0.3) · 109), 3-hydroxy-4-methoxybenzoic acid (k = (1.3±0.4) · 109). Averaged activation energies of: para-substituted phenols are EAߙpara = 11±6 kJ mol-1; 2,6-substituted phenols EAߙ2,6 = 15±4 , poly-substituted phenols EAߙpoly = 16±4 kJ mol-1. From reactivity correlations it is concluded that 4-nitrophenol, 2,6-dinitrophenol and 4-hydroxybenzoic acid react via direct electron transfer. The majority of investigated compounds react in a mixed regime with contribution of both electron transfer and H-atom abstraction. Surprisingly, changes in ionic strength do not affect the reactions dominated by electron transfer but have an influence on the rate constants of reactions with a mixed mechanism.
© by Oldenbourg Wissenschaftsverlag, Leipzig, Germany
Artikel in diesem Heft
- Physico-Chemical Aspects of Global Atmospheric Change. Dedicated to Reinhard Zellner on the occasion of his 65th birthday
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- Sources and Cycling of Tropospheric Hydroxyl Radicals – An Overview
- Kinetics and Products of the Reaction O2(1Σg+) with N2O
- An Experimental and Theoretical Study of the Reaction Between NH(X3Σ−) + SO(X3Σ−)
- Pressure Dependence of Iso-Propyl Nitrate Formation in the i-C3H7O2 + NO Reaction
- Photolysis of Trichloronitromethane (Chloropicrin) under Atmospheric Conditions
- The Gas-phase Ozonolysis of 1-Penten-3-ol, (Z)-2-Penten-1-ol and 1-Penten-3-one: Kinetics, Products and Secondary Organic Aerosol Formation
- Theoretical Study of the HOCH2OO• + HO2• Reaction: Detailed Molecular Mechanisms of the Three Reaction Channels
- Studies of the Formation and Growth of Aerosol from Molecular Iodine Precursor
- Heterogeneous Chemistry of Cl2O and HOCl on Frozen Natural Sea Salt, Recrystallized Sea Salt, KCl and NaCl Solutions at 200 and 215 K
- Atmospheric Heterogeneous Reactions of Benzo(a)pyrene
- Time Resolved Infrared Spectroscopy of Formation and Processing of Secondary Organic Aerosol
- Probing the Equilibrium Size and Hydrogen Bonding Structure in Aqueous Aerosol Droplets
- Interaction of NO2 with Soot: Oxidation and Gasification at Temperatures Between 300 and 670 K
- Uptake of Organic Acids on Ice Surfaces: Evidence for Surface Modification and Hydrate Formation
- Aqueous Phase Reactivity of Nitrate Radicals (NO3) Toward Dicarboxylic Acids
- Temperature and Ionic Strength Dependence of NO3-radical Reactions with Substituted Phenols in Aqueous Solution
Artikel in diesem Heft
- Physico-Chemical Aspects of Global Atmospheric Change. Dedicated to Reinhard Zellner on the occasion of his 65th birthday
- The Quest for the Hydroxyl-Peroxy Radical
- Sources and Cycling of Tropospheric Hydroxyl Radicals – An Overview
- Kinetics and Products of the Reaction O2(1Σg+) with N2O
- An Experimental and Theoretical Study of the Reaction Between NH(X3Σ−) + SO(X3Σ−)
- Pressure Dependence of Iso-Propyl Nitrate Formation in the i-C3H7O2 + NO Reaction
- Photolysis of Trichloronitromethane (Chloropicrin) under Atmospheric Conditions
- The Gas-phase Ozonolysis of 1-Penten-3-ol, (Z)-2-Penten-1-ol and 1-Penten-3-one: Kinetics, Products and Secondary Organic Aerosol Formation
- Theoretical Study of the HOCH2OO• + HO2• Reaction: Detailed Molecular Mechanisms of the Three Reaction Channels
- Studies of the Formation and Growth of Aerosol from Molecular Iodine Precursor
- Heterogeneous Chemistry of Cl2O and HOCl on Frozen Natural Sea Salt, Recrystallized Sea Salt, KCl and NaCl Solutions at 200 and 215 K
- Atmospheric Heterogeneous Reactions of Benzo(a)pyrene
- Time Resolved Infrared Spectroscopy of Formation and Processing of Secondary Organic Aerosol
- Probing the Equilibrium Size and Hydrogen Bonding Structure in Aqueous Aerosol Droplets
- Interaction of NO2 with Soot: Oxidation and Gasification at Temperatures Between 300 and 670 K
- Uptake of Organic Acids on Ice Surfaces: Evidence for Surface Modification and Hydrate Formation
- Aqueous Phase Reactivity of Nitrate Radicals (NO3) Toward Dicarboxylic Acids
- Temperature and Ionic Strength Dependence of NO3-radical Reactions with Substituted Phenols in Aqueous Solution
