Reaction of the hydrogen atom with nitrous oxide in aqueous solution – pulse radiolysis and theoretical study

Kazmierczak, Łukasz; Swiatla-Wojcik, Dorota; Wolszczak, Marian

doi:10.1039/c6ra27793d

Cited by 4 publications

(7 citation statements)

References 38 publications

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“…The Arrhenius dependence reported by Kazmierczak, et al, 37 if extrapolated to 100 o C, would predict a rate constant 3.7 times larger than our measurement in Table 1 The transient optical method adopted by Kazmierczak, et al 37 amounts to a competition of the pseudo-first-order reaction 3 against the second order recombination of Cl2 •radical with itself and with H • atoms. The temperature dependence of several second order reaction rates, radiation yields and extinction coefficients must be precisely known in order to extract the desired information from fitting a system of partial differential equations.…”

Section: Discussioncontrasting

confidence: 46%

“…Once this data is collected, and assuming the mechanism is complete, there is no reason that the experiment should give a wrong answer. However, we believe that somehow a systematic error entered into the work of Kazmierczak, et al 37 , and lead them to an erroneous conclusion regarding the mechanism of reaction 3.…”

Section: Discussionmentioning

confidence: 84%

“…Given the very high gas phase barrier for the direct attack at oxygen 30 37 The activation energy is reported as 62.6 kJ/mole, with Arrhenius preexponential of 8.2 x 10 15 M -1 s -1 . They compare this activation energy with ab initio calculations in the literature and additional calculations in dielectric continuum "solvent", and conclude the direct attack of H atom at the oxygen atom of N2O is the preferred mechanism in solution.…”

Section: Discussionmentioning

confidence: 99%

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Reaction rate of H atoms with N2O in hot water

Sargent

Sterniczuk

Bartels

2017

Radiation Physics and Chemistry

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The rate constant of H • atoms with N2O in water has been measured by a competition method up to 300 o C. Radiolysis with 2.5MeV electrons generated H • atoms, and the HD product from their reaction with deuterated tetrahydrofuran (THF-d8) was measured with mass spectroscopy. The concentration of THF-d8 was changed by an order of magnitude in the presence of 25mM N2O to obtain the ratio of rate constants. To determine the rate constant of H • with THF-d8, a similar competition vs. 0.2mM OHion was also measured. The reaction rate of H • with OHhas been accurately determined vs. temperature in previous work, allowing the two unknown rate constants to be deduced. Rate constant of H • with THF-d8 follows the Arrhenius law ln(k/M-1 s-1)= 27.33-(32.30 kJ/mol)/RT. Rate constant of H • with N2O follows the Arrhenius law ln(k/M-1 s-1)=24.50-(30.42 kJ/mol)/RT. In all likelihood, the N2O reaction proceeds via cis-HNNO • radical intermediate as in the gas phase, but with participation of a bridging water molecule in the 1,3 hydrogen shift to form N2 and • OH products.

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Section: Discussioncontrasting

confidence: 46%

Section: Discussionmentioning

confidence: 84%

Section: Discussionmentioning

confidence: 99%

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Reaction rate of H atoms with N2O in hot water

Sargent

Sterniczuk

Bartels

2017

Radiation Physics and Chemistry

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“…The implicit solvation model based on density (SMD) was adopted to investigate the effects of water solvent on the reaction (the dielectric constant was taken to be 78.3553 for water). [30][31][32] The relative energy and rate constants were calculated at 298.15 K, and 1 atm. The single-point energies were further rened employing coupled cluster theory at the level of CCSD(T)/6-311++G(d,p).…”

Section: Methodsmentioning

confidence: 99%

Reactions of hydroxyl radicals with benzoic acid and benzoate

Visscher

Gates

2017

RSC Adv.

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Density functional theory was used to study the mechanism and kinetics of benzoic acid with hydroxyl radicals in both gas and aqueous phases as well as benzoate with hydroxyl radicals in the aqueous phase at the M06-2X/6-311+G(d,p) level of theory. The results show that all reaction pathways involved the formation of pre-reactive complexes which in turn alter reaction energy barriers. The reaction rate constants, calculated based on classical transitional theory, followed the order of meta addition > para addition > ortho addition for the reaction of benzoic acid and hydroxyl radicals in both gas and aqueous media. The energy barrier analysis reveals that the ortho adducts were also less vulnerable to subsequent reaction. In addition, the rate constants for the addition reactions were highest for benzoate in the aqueous phase, followed by benzoic acid in the aqueous phase, then by benzoic acid in the gas phase, consistent with electrostatic potential analysis. However, the rate constants of hydrogen abstraction in the aqueous phase were much lower than that in the gas phase and thus, gas phase reactions are preferred. The incorporation of one explicit water molecule, for addition reactions between benzoic acid and hydroxyl radicals, lowered reaction rates in the aqueous phase by increasing the bond length between the oxygen and reacting carbon in the benzene ring. rsc.li/rsc-advances 35776 | RSC Adv., 2017, 7, 35776-35785 This journal is Scheme 1 Reaction pathways of BA and BZ with hydroxyl radicals. (a) Reaction pathways of BA with hydroxyl radicals. (b) Reaction pathways of BZ with hydroxyl radicals. This journal is a Note: units for gas phase rate constants and aqueous phase rate constants are cm 3 per molecule per s À1 , and M À1 s À1 , respectively. 35782 | RSC Adv., 2017, 7, 35776-35785 This journal is

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“…The reaction rate constants for the elementary reactions were calculated with the transition state theory according to eqs and . , where k Bolt is Boltzmann’s constant, T is temperature, h is Planck’s constant, E TSF and E TSB are the barrier heights with respect to the different reactants for forward and backward reactions, respectively, Γ is the tunneling factor, and are the partition functions, including translational, vibrational, and rotational contributions, of the transition state (forward and backward reactions), , H + , and , respectively. The Wigner tunneling equation was used to calculate the tunneling factor. , Since the Wigner tunneling factor can be easily obtained and only requires the imaginary frequency of transition state, it is one of the most widely used tunneling corrections . The E TSF and E TSB are energy including zero-point energy corrections and were calculated by the Gaussian 09 Software, and the k values of forward and backward reactions were calculated by using eqs and , together with where k F and k B are the rate constants of the forward and backward reactions, respectively.…”

Section: Resultsmentioning

confidence: 99%

Kinetic Modeling of Ozone Decomposition and Peroxone Oxidation of Toluene in an Aqueous Phase Using ab Initio Calculations

Esfahani

Gates

Visscher

2019

Ind. Eng. Chem. Res.

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The application of ozone along with hydrogen peroxide, commonly referred to as peroxone oxidation, is a widely investigated technique for wastewater treatment. Degradation of ozone in water is a key step in the pollutant degradation mechanism, particularly in peroxone oxidation. However, the degradation of ozone in water is not understood at a low pH (<6). This study reveals that current ozone degradation models overestimate degradation at a low pH because the rate constants involved in the dissociation equilibrium of the hydroperoxyl radical are inaccurate. Here, the rate constants of forward and backward reactions were calculated with ab initio quantum chemical calculations computed from the CCSD (T) theory to be 1.45 × 103 s–1 and 8.6 × 107 m3 kmol –1 s–1, respectively. After modifying the current kinetic model by using the calculated rate constants, the predictions of ozone half-lives at a low pH (<6) are improved by 1–2 orders of magnitude in pure water (without organic matter and carbonate species) in comparison with the available experimental results. The ozone decomposition kinetic model was used to develop a comprehensive kinetic model for peroxone oxidation of toluene. The results demonstrate that the new rate constants considerably improve the peroxone oxidation process as well.

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Reaction of the hydrogen atom with nitrous oxide in aqueous solution – pulse radiolysis and theoretical study

Abstract: The UB3LYP/cc-pVTZ computations using three solvent models and pulse radiolysis measurements show predominance of the direct reaction path via [H–ONN]‡ in aqueous solution.

Cited by 4 publications

References 38 publications

Reaction rate of H atoms with N2O in hot water

Reaction rate of H atoms with N2O in hot water

Reactions of hydroxyl radicals with benzoic acid and benzoate

Kinetic Modeling of Ozone Decomposition and Peroxone Oxidation of Toluene in an Aqueous Phase Using ab Initio Calculations

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