Observation of the Unimolecular Decomposition Pathways of Chemically Activated Acetic Acid by Fourier Transform Infrared Emission Spectrometry

Butkovskaya, N. I.; Manke, Gerald C.; Setser, D. W.

doi:10.1021/j100028a011

Cited by 25 publications

(46 citation statements)

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“…Our measured rate constant data show that the tendency of the dehydration reaction to occur is about two times higher than that of the decarboxylation reaction, as observed previously by [19][20][21]. Mackie and Doolan [18], on the other hand, argued that both reactions have about the same probability.…”

Section: Acetic Acid Pyrolysissupporting

confidence: 86%

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Unimolecular decomposition of formic and acetic acids: A shock tube/laser absorption study

Elwardany

Nasir

Es-sebbar

et al. 2015

Proceedings of the Combustion Institute

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The thermal decomposition of formic acid (HCOOH) and acetic acid (CH 3 COOH), two carboxylic acids which play an important role in oxygenate combustion chemistry, were investigated behind reflected shock waves using laser absorption. The rate constants of the primary decomposition pathways of these acids:were measured using simultaneous infrared laser absorption of CO, CO 2 and H 2 O at wavelengths of 4.56, 4.18 and 2.93 microns, respectively. Reaction test conditions covered temperatures from 1230 to 1821 K and pressures from 1.0 to 6.5 atm for dilute mixtures of acids (0.25 -0.6%) in argon. The rate constants of dehydration (R1) and decarboxylation (R2) reactions of formic acid were calculated by fitting exponential functions to the measured CO, CO 2 and H 2 O time-history profiles. These two decomposition channels were found to be in the fall-off region and have a branching ratio, ! ! , of approximately 20 over the range of pressures studied here. The best-fit Arrhenius expressions of the first-order rates of R1 and R2were found to be:! 6.5 atm = 9.12 ×10 !" exp −30275 s -1 (±32%)The rate constants for acetic acid decomposition were obtained by fitting simulated profiles, using an acetic acid pyrolysis mechanism, to the measured species time-histories. The branching ratio, ! ! , was found to be approximately 2. The decarboxylation and dehydration reactions of acetic acid appear to be in the falloff region over the tested pressure range:! 1 atm = 3.18×10 !! ×exp −28679 s -1 (±30%)! 6 atm = 3.51×10 !" ×exp −31330 s -1 (±26%)! 1 atm = 7.9 ×10 !! exp −29056 s -1 (±34%).! 6 atm = 6.34×10 !" ×exp −31330 s -1 (±31%).

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Section: Acetic Acid Pyrolysissupporting

confidence: 86%

“…Another study by Butkovskaya et al [19] used a flow reactor and IR emission of CO 2 and H 2 O to study acetic acid decomposition. They concluded that the !…”

Section: Introductionmentioning

confidence: 99%

Unimolecular decomposition of formic and acetic acids: A shock tube/laser absorption study

Elwardany

Nasir

Es-sebbar

et al. 2015

Proceedings of the Combustion Institute

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“…As there is no literature value for the 3 and v 3 ϭ0 levels, respectively, we obtained a ratio of ͓HOD͔/͓D 2 O͔Ӎ3.1Ϯ0.8, which corresponds to a kinetic isotope effect of reaction ͑4͒ of k H /2k D ϭ1.5Ϯ0.4. The error limits correspond to a total uncertainty of about 26%, as estimated for reaction ͑3͒.…”

Section: E Vibrational Distribution For D 2 O From Reaction (4)mentioning

confidence: 83%

“…1,[3][4][5] Based upon the experimental relaxation rate constants for H 2 O in Ar and H 2 , 8,9 it was concluded that at Ar pressures Ϸ0.7 Torr and reaction times Ϸ0.3 ms, equilibration exists between populations in the 1 and 3 levels in H 2 O and D 2 O and between the 1 and 2 2 levels in HOD. However, extensive studies of the OHϩHBr reaction 4 for 0.5 Torr ͑0.25 ms͒, 0.7 Torr ͑0.35 ms͒, and 1.0 Torr ͑0.5 ms͒ show no evidence for any significant loss of vibrational energy for experiments at pressure Ͻ1 Torr and observation time Ͻ0.4 ms.…”

Section: A Chemiluminescent Spectramentioning

confidence: 99%

“…Since the stretching normal modes 1 ͑O-D stretching͒ and 3 ͑O-H stretching͒ of the HOD molecule have quite different frequencies, the populations in these individual modes can be obtained by analysis of the spectra from HOD formed from the deutero-substituted ethanol molecules. The assignment of the vibrational energy of HOD was the main objective of this study, but we also have improved the analysis for H 2 O spectra.…”

Section: Introductionmentioning

confidence: 99%

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Unimolecular decomposition of chemically activated deutero-substituted ethanol molecules studied by infrared chemiluminescence from H2O, HOD, and D2O

Butkovskaya

Setser

1996

The Journal of Chemical Physics

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The isotope effect in solvation dynamics and nonadiabatic relaxation: A quantum simulation study of the photoexcited solvated electron in D2OThe farinfrared vibration-rotation-tunneling spectrum of the water tetramerd8 with an excitation energy of about 100 kcal mol Ϫ1 were observed by infrared chemiluminescence in the 2400-3900 cm Ϫ1 range. The activated ethanol molecules were produced via the successive reactions HϩCH 2 ICH 2 OH→HIϩCH 2 CH 2 OH and HϩCH 2 CH 2 OH→CH 3 CH 2 OH* in a fast flow reactor that was observed with a Fourier transform spectrometer. The vibrational distributions of the H 2 O, HOD, and D 2 O molecules were determined by computer simulation of the experimental spectra; the distributions decline with increasing vibrational energy giving ͗ f v ͘ϭ0.15 and ͗ f v ͘ϭ0.14 for H 2 O and HOD from the decomposition of C 2 H 5 OH* and C 2 H 5 OD*, respectively.The vibrational energy in the bending mode of H 2 O is comparable to the energy in the stretching modes. Comparison with the statistical vibrational distributions shows a substantial overpopulation of the bending levels and a preferential excitation of one O-H or O-D stretching quantum in HOD from C 2 H 5 OD or CH 2 DCH 2 OH, respectively, i.e., in the newly formed bond. Kinetic isotope effects of ͓H 2 O͔/͓HOD͔ϭ3.6Ϯ0.8 and ͓HOD͔/͓D 2 O͔ϭ3.1Ϯ0.8 were found for the two elimination pathways of CH 2 DCH 2 OH* and CH 2 DCH 2 OD*, respectively, which agree with calculated RRKM values of k H 2 O /k HOD ϭ 3.2 and k HOD /k D 2 O ϭ 2.7.

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Structure and optical properties of iron oxide films prepared by a modified wet-chemical method

Carbajal-Franco

Eastman

Ramana

2013

Ceramics International

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Observation of the Unimolecular Decomposition Pathways of Chemically Activated Acetic Acid by Fourier Transform Infrared Emission Spectrometry

Cited by 25 publications

References 4 publications

Unimolecular decomposition of formic and acetic acids: A shock tube/laser absorption study

Unimolecular decomposition of formic and acetic acids: A shock tube/laser absorption study

Unimolecular decomposition of chemically activated deutero-substituted ethanol molecules studied by infrared chemiluminescence from H2O, HOD, and D2O

Structure and optical properties of iron oxide films prepared by a modified wet-chemical method

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