Enthalpy of formation of acetonyl radical and its analogs in the gas phase

Орлов, В. М.; Misharev, A. D.; Takhistov, V. V.; Ryabinkin, I. I.

doi:10.1007/bf00962734

Cited by 3 publications

(13 citation statements)

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“…• CH 2 CHCH 2 Radical. Our selected methods generally give values for the heat of formation for allyl radical that lie within the range spanned by the experimental values of Seetula,42g Berkowitz et al,30g and Ellison et al42e A recent high level study by Feller and Dixon,6d involving extrapolations to the complete one-particle basis set limit, obtained a value of 178.6 ± 6.3 kJ mol -1 for the heat of formation of allyl radical, in close agreement with our Wn results. In addition, we have previously 9c calculated values for Δ f H 0 (•CH 2 CHCH 2 ) at a range of levels including G2, G2-RAD(QCISD), G3, G3//B3-LYP, CBS-RAD, CBS-QB3, CBS-APNO, and Martin-3.…”

Section: Resultsmentioning

confidence: 97%

“…C. Radical Heats of Formation: Predictions. Table contains a small selection of radicals for which there are greater uncertainties associated with the experimental heats of formation . On the basis of our assessment study, we use the G3-RAD, G3X-RAD, G3X, W1h, W1, W2h, and W2 methods to attempt to assign reliable heats of formation.…”

Section: Resultsmentioning

confidence: 99%

“…b From Curtiss et al 3f, c From Parthiban and Martin. 5i, d From the JANAF Thermochemical Tables. 25d e From Seetula 42g42e g From Berkowitz et al30g h From Lafleur et al42h i From Shea et al,42f back-corrected to 0 K using theoretical temperature correction from B3-LYP/6-31G(d) frequencies (scaled by 0.9989) …”

Section: Resultsmentioning

confidence: 99%

“…25d e From Seetula 42g42e g From Berkowitz et al30g h From Lafleur et al42h i From Shea et al,42f back-corrected to 0 K using theoretical temperature correction from B3-LYP/6-31G(d) frequencies (scaled by 0.9989) 42d back-corrected to 0 K using theoretical temperature correction from B3-LYP/6-31G(d) frequencies (scaled by 0.9989) …”

Section: Resultsmentioning

confidence: 99%

“…k From Wenthold and Squires 42c42b back-corrected to 0 K using theoretical temperature correction from B3-LYP/6-31G(d) frequencies (scaled by 0.9989) 42a…”

Section: Resultsmentioning

confidence: 99%

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An Assessment of the Performance of High-Level Theoretical Procedures in the Computation of the Heats of Formation of Small Open-Shell Molecules

2002

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The heats of formation at 0 K (Δf H 0) of 29 small (containing up to 3 heavy atoms) open-shell molecules, with accurately known experimental values, have been calculated using a number of high-level theoretical procedures. The theoretical methods examined include variants of Gaussian-n (G2, G2-RAD(RMP2), G2-RAD(B3-LYP), G2-RAD(QCISD), G3, G3-RAD, G3X, G3X-RAD, G3(MP2), G3(MP2)-RAD, G3X(MP2) and G3X(MP2)-RAD), CBS (CBS-APNO, CBS-Q, CBS-RAD and CBS-QB3), and Martin extrapolation (Martin-2, Martin-3, W1, W1‘, W1h, W2h and W2) procedures. The open-shell systems include doublet radicals (•BeH, •CH, •CH3, •NH2, •OH, •SiH3, •PH2, •SH, •N2 +, •NO, •ONO, •O2 -, •CN, •CO+, •CS+, •CCH, •CHO, •OOH, •CHCH2, •CH2CH3, •CH2OH, •OCH3, •SCH3 and •COCH3) and triplet biradicals (:CH2, :NH, :SiH2, :O2, and :S2). The results for these systems are used to assess the performance of the various theoretical methods. The smallest mean absolute deviations (MADs) from experiment are found with the G3-RAD, G3X-RAD, G3X, W1h, W2, W1, and W2h procedures with MADs lying in the range 2.0−2.5 kJ mol-1. The smallest values for the largest deviation (LD) from experiment are found with the G3X, G3X-RAD, W2, and W2h procedures and are ±6.4 kJ mol-1. A selection of the most accurate theoretical procedures (G3-RAD, G3X-RAD, G3X, W1h, W2, W1, and W2h) is used to predict the heats of formation for several radicals (•OF, •CH2CHCH2, •CH2CN, •CH2COOH, and •CH2C6H5) for which there are greater uncertainties associated with the experimental values.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“…k From Wenthold and Squires 42c42b back-corrected to 0 K using theoretical temperature correction from B3-LYP/6-31G(d) frequencies (scaled by 0.9989) 42a…”

Section: Resultsmentioning

confidence: 99%

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An Assessment of the Performance of High-Level Theoretical Procedures in the Computation of the Heats of Formation of Small Open-Shell Molecules

2002

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Thermochemistry of C−C and C−H Bond Breaking in Fatty Acid Methyl Esters

et al. 2007

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Thermochemistry of Acetonyl and Related Radicals

et al. 2006

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Density functional and ab initio calculations at CBS-QB3 levels of theory were employed with a series of isodesmic reactions to determine the thermochemistry of the 2-oxopropyl or acetonyl radical (CH(3)COC*H2). In turn, this was used to determine formation enthalpies of 2-oxoethyl or formylmethyl (C*H(2)CHO), 2-oxobutyl (C*H(2)COC(2)H(5)), 1-methyl-2-oxopropyl or methylacetonyl (C*H(CH(3))COCH(3)), 1-methyl-2-oxobutyl (C*H(CH(3))COC(2)H(5)), and 3-oxopentyl (C*H(2)CH2COC(2)H(5)). Our computed standard enthalpy of formation of -34.9 +/- 1.9 kJ mol-1 and a resonance stabilization energy of approximately 22 kJ mol(-1) for acetonyl are in good agreement with recent re-determinations, which have indicated a substantial lowering in the long-established value for DeltaH(f)o (298.15 K). A bond dissociation energy of 401 kJ mol(-1) is suggested for the C-H bond in acetone with consistent values for the others. The calculations support the enthalpy of formation of acetaldehyde obtained from combustion experiments of -166.1 kJ mol(-1) rather than the figure of -170.7 kJ mol(-1) extracted from enthalpies of reduction and, in addition, serve to reduce the uncertainty in DeltaH(f)o the 2-oxoethyl radical to +13 +/- 2 kJ mol(-1).

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Enthalpy of formation of acetonyl radical and its analogs in the gas phase

Cited by 3 publications

References 2 publications

An Assessment of the Performance of High-Level Theoretical Procedures in the Computation of the Heats of Formation of Small Open-Shell Molecules

An Assessment of the Performance of High-Level Theoretical Procedures in the Computation of the Heats of Formation of Small Open-Shell Molecules

Thermochemistry of C−C and C−H Bond Breaking in Fatty Acid Methyl Esters

Thermochemistry of Acetonyl and Related Radicals

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