Methane Loss in the Infrared Multiphoton Dissociation of Acetic Acid

Longfellow, Cheryl A.; Lee, Yuan T.

doi:10.1021/j100042a030

Cited by 22 publications

(23 citation statements)

References 13 publications

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“…Methane elimination is one of these new channels, with a hydrogen atom on one methyl group moving to the other group to form a methane molecule and leaving CH 2 N 2 , diazomethane, as the other fragment. A similar process was observed before in the thermal dissociation of acetic acid, in which the hydrogen atom on the hydroxy group could move to the methyl group to form methane. ,− It is obvious that such a reaction requires the two methyl groups on the same side and could happen only for cis -azomethane.…”

Section: Resultssupporting

confidence: 60%

Ab Initio Studies on the Thermal Dissociation Channels of cis- and trans-Azomethane

Hon

Liu

2002

J. Phys. Chem. A

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The unimolecular dissociation of azomethane is studied by first sampling the reaction channels with a density functional theory based ab initio molecular dynamics method and then by mapping out the reaction barrier and transition structure for each channel with Gaussian based ab initio method at G3 and B3LYP/6-31G(d) levels. A number of new dissociation channels are identified, and all of them involve the migration of H atoms or the breaking of a C-H bond. There is also notable difference among these channels for trans-and cis-azomethane. In the gas phase, a CH 4 loss channel could be present in the dissociation of cis-azomethane. For N-N bond cleavage observed on metal surfaces, the hydrogen migration from C to N atoms, by either 1,2-or 1,3-hydrogen shifts, is the first step. Further H migration could result in N-N cleavage and produce HCN and CH 3 NH 2 , both observed in previous surface experiments. The concerted C-H bond cleavages in cis-azomethane could also produce H 2 .

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Section: Resultssupporting

confidence: 60%

Ab Initio Studies on the Thermal Dissociation Channels of cis- and trans-Azomethane

Hon

Liu

2002

J. Phys. Chem. A

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“…The thermal decomposition of acetic acid has been studied in flow systems, 15,16 shock tube experiments, 17,18 and through IR mutiphoton dissociation. 19 Thermal decomposition in the gas phase occurs through two competing processes, dehydration and decarboxylation:…”

Section: Introductionmentioning

confidence: 99%

Photodissociation spectroscopy of the Mg+-acetic acid complex

Abate

Kleiber

2006

The Journal of Chemical Physics

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We have studied the structure and photodissociation of Mg(+)-acetic acid clusters. Ab initio calculations suggest four relatively strongly bound ground state isomers for the [MgC(2)H(4)O(2)](+) complex. These isomers include the cis and trans forms of the Mg(+)-acetic acid association complex with Mg(+) bonded to the carbonyl O atom of acetic acid, the Mg(+)-acetic acid association complex with Mg(+) bonded to the hydroxyl O atom of acetic acid, or to a Mg(+)-ethenediol association complex. Photodissociation through the Mg(+)-based 3p<--3s absorption bands in the near UV leads to direct (nonreactive) and reactive dissociation products: Mg(+), MgOH(+), Mg(H(2)O)(+), CH(3)CO(+), and MgCH(3) (+). At low energies the dominant reactive quenching pathway is through dehydration to Mg(H(2)O)(+), but additional reaction channels involving C-H and C-C bond activation are also open at higher energies.

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“…Experimentally, thermal decomposition in the gaseous phase occurs mainly via the decarboxylation and dehydration channels in a 1:2 proportion, yielding carbon dioxide with methane and ketene (CH 2 dCdO) with water, respectively. 19, 20 The gas-phase photodecomposition of acetic acid was shown to produce mainly acetyl and hydroxyl radicals. [21][22][23][24] The present work has a 2-fold task.…”

Section: Introductionmentioning

confidence: 99%

Photochemistry and Vibrational Spectroscopy of the Trans and Cis Conformers of Acetic Acid in Solid Ar

et al. 2004

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Acetic acid monomer has two stable geometries, the cis and trans conformers. The high-energy cis conformer has been recently detected experimentally for the first time [Maçôas et al. J. Am. Chem. Soc. 2003, 125, 16188]. The cis conformer can be produced in low-temperature rare-gas matrixes upon vibrational excitation of the ground-state trans conformer. Fast tunneling from cis-to trans-acetic acid takes place even at the lowest working temperatures (8 K), limiting the time available to study the high-energy form. Deuteration of the hydroxyl group reduces the tunneling rate by approximately 4 orders of magnitude, increasing accordingly the lifetime of the unstable conformer and its available concentration. In this work, we present a detailed analysis of the vibrational spectra of the cis form of four acetic acid isotopologues (CH 3 COOH, CH 3 COOD, CD 3 COOH and CD 3 COOD). Photolysis (193 nm) of the trans and cis forms of the perdeuterated compound was performed to evaluate the possible conformational dependence of photodissociation of acetic acid. However, no evidence of conformer specific photodissociation was found. The UV photolysis of the matrix-isolated acetic acid reveals very different products from the gas phase. Methanol complexed with carbon monoxide is the major product of photolysis of acetic acid isolated in Ar matrixes whereas it has never been observed as a photolysis product in the gas phase.

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Methane Loss in the Infrared Multiphoton Dissociation of Acetic Acid

Cited by 22 publications

References 13 publications

Ab Initio Studies on the Thermal Dissociation Channels of cis- and trans-Azomethane

Ab Initio Studies on the Thermal Dissociation Channels of cis- and trans-Azomethane

Photodissociation spectroscopy of the Mg+-acetic acid complex

Photochemistry and Vibrational Spectroscopy of the Trans and Cis Conformers of Acetic Acid in Solid Ar

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