A FT IR spectroscopic study of the ozone-ethene reaction mechanism in oxygen-rich mixtures

Su, Fu; Calvert, Jack G.; Shaw, John H.

doi:10.1021/j100440a003

Cited by 131 publications

(119 citation statements)

References 3 publications

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“…This statement is applicable towards the ozonolysis of most unsaturated compounds. A significant fraction of gas-phase CI undergoes unimolecular decomposition and these channels have been established for the simplest CI, CH 2 OO (Horie and Moortgat, 1991;Su et al, 1980;Herron and Huie, 1977). These products include OH and other free-radicals (Martinez et al, 1981;Neeb et al, 1998;Fenske et al, 2000;Gutbrod et al, 1997;Lewin et al, 2001;Aschmann et al, 2002;Ariya et al, 2000;Atkinson et al, 1995;Gutbrod et al, 1996).…”

Section: Overview Of Ozonolysismentioning

confidence: 99%

The oleic acid-ozone heterogeneous reaction system: products, kinetics, secondary chemistry, and atmospheric implications of a model system – a review

2007

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Abstract. The heterogeneous processing of organic aerosols by trace oxidants has many implications to atmospheric chemistry and climate regulation. This review covers a model heterogeneous reaction system (HRS): the oleic acidozone HRS and other reaction systems featuring fatty acids, and their derivatives. The analysis of the commonly observed aldehyde and organic acid products of ozonolysis (azelaic acid, nonanoic acid, 9-oxononanoic acid, nonanal) is described. The relative product yields are noted and explained by the observation of secondary chemical reactions. The secondary reaction products arising from reactive Criegee intermediates are mainly peroxidic, notably secondary ozonides and α-acyloxyalkyl hydroperoxide oligomers and polymers, and their formation is in accord with solution and liquidphase ozonolysis. These highly oxygenated products are of low volatility and hydrophilic which may enhance the ability of particles to act as cloud condensation nuclei (CCN). The kinetic description of this HRS is critically reviewed. Most kinetic studies suggest this oxidative processing is either a near surface reaction that is limited by the diffusion of ozone or a surface based reaction. Internally mixed particles and coatings represent the next stage in the progression towards more realistic proxies of tropospheric organic aerosols and a description of the products and the kinetics resulting from the ozonolysis of these proxies, which are based on fatty acids or their derivatives, is presented. Finally, the main atmospheric implications of oxidative processing of particulate containing fatty acids are presented. These implications include the extended lifetime of unsaturated species in the troposphere facilitated by the presence of solids, semi-solids or viscous phases, and an enhanced rate of ozone uptake by particulate unsaturates compared to corresponding gas-phase organics.Correspondence to: G. A. Petrucci (giuseppe.petrucci@uvm.edu) Ozonolysis of oleic acid enhances its CCN activity, which implies that oxidatively processed particulate may contribute to indirect forcing of radiation.

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Section: Overview Of Ozonolysismentioning

confidence: 99%

The oleic acid-ozone heterogeneous reaction system: products, kinetics, secondary chemistry, and atmospheric implications of a model system – a review

2007

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“…These values indicate that M14 will be the major product of the SOZ cleavage. Hydroxymethyl formate was initially identified as a transitory product in the gas-phase ozonolysis of ethylene, [21,26,82] and was supposed to be formed as a product of the carbonyl oxide formaldehyde reaction, but further experimental work indicated that this transitory product could be hydroperoxymethyl formate, [32,33] although the mechanism for its formation is only speculative. [32] The energy barriers for the key structures TS11 and TS12, relative to M10 (SOZ), computed at CASPT2 levels of theory, differ by 4.4 and 10.7 kcal mol À1 respectively from the QCISD(T) values (see footnote [c] in Table 2).…”

mentioning

confidence: 99%

“…From the energy barrier heights in Figure 6 one may infer that the yield of CO 2 obtained through this process should be slightly greater than that of CO, which contrasts with the measured yields of these products in gas-phase ethylene ozonolysis. [2,6,21,39,82] However, Neeb et al [39] recently concluded that a fraction of the CO produced in ethylene ozonolysis is due to a bimolecular reaction other than H 2 COO unimolecular decomposition.…”

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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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“…To our knowledge there are no comprehensive product studies of the ozonolysis of MVK or MAC, so little information concerning possible reactions of the Criegee-intermediates is available. However, it is known that HCOOH is a product of the isomerisation of the H 2 COO Criegee-intermediate [18,19] and may react according to reaction (4). The formation of hydroperoxymethyl formate (HPMF, CH 2 (OOH)-O-CHO was observed in all experiments, although no attempts were made to quantify this product.…”

Section: ϫ1 ϫ1mentioning

confidence: 97%

Rate constants for the reactions of methylvinyl ketone, methacrolein, methacrylic acid, and acrylic acid with ozone

Neeb

Kolloff

Koch

et al. 1998

Int. J. Chem. Kinet.

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Rate constants for the reaction of ozone with methylvinyl ketone (H 2 C " CHC(O)CH 3 ), methacrolein (H 2 C" C(CH 3 )CHO), methacrylic acid (H 2 C "C(CH 3 )C(O)OH), and acrylic acid (H 2 C " CHC(O)OH) were measured at room temperature in the pres-(296 Ϯ 2 K) ence of a sufficient amount of cyclohexane to scavenge OH-radicals. Results from pseudofirst-order experiments in the presence of excess ozone were found not to be consistent with relative rate measurements. It appeared that the formation of the so-called Criegee-intermediates leads to an enhanced decrease in the concentration of the two organic acids investigated. It is shown that the presence of formic acid, which is known to react efficiently with Criegee-intermediates, diminishes the observed removal rate of the organic acids. The rate constant for the reaction of ozone with the unsaturated carbonyl compounds methylvinyl ketone and methacrolein was found not to be influenced by the addition of formic acid. Rate constants for the reaction of ozone determined in the presence of excess formic acid are (in ): methylvinyl ketone methacrolein 3 Ϫ1 Ϫ1 Ϫ18

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A FT IR spectroscopic study of the ozone-ethene reaction mechanism in oxygen-rich mixtures

Cited by 131 publications

References 3 publications

The oleic acid-ozone heterogeneous reaction system: products, kinetics, secondary chemistry, and atmospheric implications of a model system – a review

The oleic acid-ozone heterogeneous reaction system: products, kinetics, secondary chemistry, and atmospheric implications of a model system – a review

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

Rate constants for the reactions of methylvinyl ketone, methacrolein, methacrylic acid, and acrylic acid with ozone

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