Energetics, Kinetics, and Product Distributions of the Reactions of Ozone with Ethene and 2,3-Dimethyl-2-butene

Olzmann, Matthias; Kraka, Elfi; Cremer, Dieter; Gutbrod, Roland; Andersson, Stefan

doi:10.1021/jp971663e

Cited by 210 publications

(323 citation statements)

References 57 publications

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“…It can be noted here, that the addition of diffuse or polarization function does not affect the energy barrier of the TS 1 A. Moreover, the activation energy of the phenanthrene ozonolysis, determined using the B3LYP/6-31G(d) method, is comparable with those reported previously for the ozonolysis reaction of ethene [46], isoprene [47,48], and butadiene [49].…”

Section: Potential Energy Surface Of the Ozonolysis Reaction Of Phenasupporting

confidence: 85%

A Computational Study of the Ozonolysis of Phenanthrene

et al. 2017

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A computational study of the ozonolysis of phenanthrene has been carried out using DFT methods (B3LYP and M06-2X). The reaction mechanism for the ozonolysis was studied in both gas phase and in solution, using the polarizable continuum solvation model. The structures for all proposed reaction mechanisms were optimized using M06-2X and B3LYP methods with 6-31G(d), 6-31+G(d), and 6-31G(2df,p) basis sets. In solution, all structures were optimized using B3LYP/6-31+G(d,p) and polarizable continuum solvation model. Six different mechanistic pathways were explored for the ozonolysis of phenanthrene that forms aldehyde compounds. The activation energy of the formation of the primary ozonide intermediate in pathway A is 13 kJ mol −1 in the polarizable continuum model with the B3LYP/6-31+G(d,p) method. This reaction is followed by a dissociation into a zwitterionic Criegee intermediate with an activation energy of 76 kJ mol −1 in polarizable continuum model with B3LYP/6-31+G(d,p). Furthermore, the nucleophilic addition reactions of methanol to the Criegee intermediate have been studied along two pathways, B1 and B2. The water-mediated mechanism for pathways B2 and C2, where the water molecule acts as a mediator through a 1,5-proton shift, dropped the activation barriers by 18 and 26 kJ mol −1 , respectively, based on B3LYP/6-31G(2df,p) method. The solvation model (polarizable continuum) reduces the energy barriers for all pathways except for the reaction of methanol with the Criegee intermediate. This study provides an insight into understanding the mechanism of transformation of this pollutant into non-toxic compounds.

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Section: Potential Energy Surface Of the Ozonolysis Reaction Of Phenasupporting

confidence: 85%

A Computational Study of the Ozonolysis of Phenanthrene

et al. 2017

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“…This exothermicity is comparable with the experimental value of 45 AE 6 kcal mol À1 and other theoretical estimates (in the 43.7 ± 57.3 kcal mol À1 range). [14,23,29,72] The activation energy relative to the reactants is computed to be 5.0 kcal mol À1 at 0 K. If we take into account the prediction from ab initio results in the literature that the , [68] we can conclude that the computed activation energy should be about 5.8 kcal mol…”

Section: Resultsmentioning

confidence: 95%

“…The concerted mechanism leads to the Criegee intermediates, which have been discussed in the literature. [14,22,29] The stepwise path begins with the cleavage of the O ± O bond leading to the biradical OCH 2 CH 2 OO, which in turn decomposes into different molecular fragments. …”

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confidence: 99%

The Ozonolysis of Ethylene: A Theoretical Study of the Gas-Phase Reaction Mechanism

1999

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The gas-phase reaction mechanism of ethylene ozonolysis has been investigated from a theoretical point of view. The formation of the ethylene primary ozonide (1,2,3-trioxolane, POZ) from the ozone ± ethylene reaction is calculated to be exothermic by 49.2 kcal mol À1 with an activation energy of 5.0 kcal mol À1 at 0 K, in agreement with experimental estimates. We have found two different paths for the cleavage of POZ, namely a concerted and a stepwise mechanism. The concerted path leads to the formation of Criegee intermediates (carbonyl oxide ± formaldehyde pairs), for which we have calculated an activation energy of 18.7 kcal mol À1 at 0 K. The non-concerted mechanism involves three different routes for the POZ decomposition, leading to the formation of Criegee intermediates with a computed activation energy of 21.6 kcal mol À1 at 0 K; to hydroperoxyacetaldehyde with a calculated activation energy of 22.8 kcal mol À1 at 0 K; and to oxirane excited molecular oxygen ( 1 D g ) with a higher activation energy. Moreover, hydroperoxyacetaldehyde is formed with an excess of energy, so that it can decompose yielding OH radicals. The reaction of carbonyl oxide and formaldehyde produces the ethylene secondary ozonide (1,2,4-trioxolane, SOZ) and involves the formation of a van der Waals complex on the reaction coordinate, prior to the transition state. The process is calculated to be exothermic by 46.0 kcal mol À1 and the energy of the transition state is computed to be lower than that of the reactants: this process can therefore be considered barrierless. SOZ cleaves by a stepwise mechanism and we have found two different fates for its decomposition: dioxymethane formaldehyde, and hydroxymethyl formate. The former is calculated to be endothermic by 33.3 kcal mol À1 with an energy barrier of 48.7 kcal mol À1, whereas the tautomerization of SOZ leading to hydroxymethyl formate is highly exothermic (72.2 kcal mol À1) and has an activation energy of 32.6 kcal mol À1 at 0 K. The unimolecular decomposition of dioxymethane, following three different paths, is also reported: dissociation into CO 2 H 2 , which is highly exothermic (111.6 kcal mol À1) and has a low energy barrier (3.0 kcal mol À1 ); isomerization to formic acid, also highly exothermic (101.9 kcal mol À1 ) with a low activation energy (2.2 kcal mol À1 at 0 K); and radical fragmentation into H HCOO, in a slightly endothermic process (4.9 kcal mol À1) with an activation energy of 18.4 kcal mol À1 at 0 K. The dissociation of formic acid into H 2 , CO 2 , CO and H 2 O and the decomposition of HCOO into H radicals CO 2 are also discussed.

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“…Again, direct measurements of the lifetimes of the stabilized intermediates have not been possible so far, and reported values span orders of magnitudes (e.g. Welz et al, 2012;Olzmann et al, 1997).…”

Section: Uncertaintiesmentioning

confidence: 99%

Oxidation of SO<sub>2</sub> by stabilized Criegee intermediate (sCI) radicals as a crucial source for atmospheric sulfuric acid concentrations

et al. 2013

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Abstract. The effect of increased reaction rates of stabilized Criegee intermediates (sCIs) with SO2 to produce sulfuric acid is investigated using data from two different locations, SMEAR II, Hyytiälä, Finland, and Hohenpeissenberg, Germany. Results from MALTE, a zero-dimensional model, show that using previous values for the rate coefficients of sCI + SO2, the model underestimates gas phase H2SO4 by up to a factor of two when compared to measurements. Using the rate coefficients recently calculated by Mauldin et al. (2012) increases sulfuric acid by 30–40%. Increasing the rate coefficient for formaldehyde oxide (CH2OO) with SO2 according to the values recommended by Welz et al. (2012) increases the H2SO4 yield by 3–6%. Taken together, these increases lead to the conclusion that, depending on their concentrations, the reaction of stabilized Criegee intermediates with SO2 could contribute as much as 33–46% to atmospheric sulfuric acid gas phase concentrations at ground level. Using the SMEAR II data, results from SOSA, a one-dimensional model, show that the contribution from sCI reactions to sulfuric acid production is most important in the canopy, where the concentrations of organic compounds are the highest, but can have significant effects on sulfuric acid concentrations up to 100 m. The recent findings that the reaction of sCI + SO2 is much faster than previously thought together with these results show that the inclusion of this new oxidation mechanism could be crucial in regional as well as global models.

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Energetics, Kinetics, and Product Distributions of the Reactions of Ozone with Ethene and 2,3-Dimethyl-2-butene

Cited by 210 publications

References 57 publications

A Computational Study of the Ozonolysis of Phenanthrene

A Computational Study of the Ozonolysis of Phenanthrene

The Ozonolysis of Ethylene: A Theoretical Study of the Gas-Phase Reaction Mechanism

Oxidation of SO<sub>2</sub> by stabilized Criegee intermediate (sCI) radicals as a crucial source for atmospheric sulfuric acid concentrations

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Energetics, Kinetics, and Product Distributions of the Reactions of Ozone with Ethene and 2,3-Dimethyl-2-butene

Cited by 210 publications

References 57 publications

A Computational Study of the Ozonolysis of Phenanthrene

A Computational Study of the Ozonolysis of Phenanthrene

The Ozonolysis of Ethylene: A Theoretical Study of the Gas-Phase Reaction Mechanism

Oxidation of SO&lt;sub&gt;2&lt;/sub&gt; by stabilized Criegee intermediate (sCI) radicals as a crucial source for atmospheric sulfuric acid concentrations

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Oxidation of SO<sub>2</sub> by stabilized Criegee intermediate (sCI) radicals as a crucial source for atmospheric sulfuric acid concentrations