Enthalpies of combustion of the three aminopyridines and the three cyanopyridines

Bickerton, J.; Pilcher, G.; Al-Takhin, Ghassan

doi:10.1016/0021-9614(84)90175-7

Cited by 113 publications

(70 citation statements)

References 13 publications

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“…14 This calorimeter has been transferred from Manchester to Porto and was used mainly as previously described but with a few changes in technique because of the different auxiliary equipment used. 15 The electrical energy for ignition was determined from the change in potential across a 1400 µF condenser on discharge through the platinum ignition wire.…”

Section: Methodsmentioning

confidence: 99%

Thermochemical and Theoretical Studies of Dimethylpyridine-2,6-dicarboxylate and Pyridine-2,3-, Pyridine-2,5-, and Pyridine-2,6-dicarboxylic Acids

et al. 2005

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The standard (p°) 0.1 MPa) molar enthalpies of formation for gaseous pyridine-2,5-dicarboxylic acid, pyridine-2,6-dicarboxylic acid, and dimethylpyridine-2,6-dicarboxylate were derived from the standard molar enthalpies of combustion, in oxygen, at T ) 298.15 K, measured by static bomb combustion calorimetry, and the standard molar enthalpies of sublimation, at 298.15 K, measured by Calvet microcalorimetry: pyridine-2,5-dicarboxylic acid, -(580.6 ( 5.0) kJ‚mol -1 ; pyridine-2,6-dicarboxylic acid, -(608.0 ( 6.1) kJ‚mol -1 ; dimethylpyridine-2,6-dicarboxylate, -(562.4 ( 4.2) kJ‚mol -1 . The enthalpy of formation for crystalline pyridine-2,3-dicarboxylic acid was also derived from combustion calorimetry measurements as -(733.1 ( 2.0) kJ‚mol -1 . In addition, theoretical calculations using the density functional theory and the B3LYP/6-311G** hybrid exchange-correlation energy functional have been performed for these molecules in order to obtain the most stable geometries and to access their relative stabilities. The good correlation obtained between experimental and theoretical results allowed the estimation of the enthalpy of sublimation for pyridine-2,3-dicarboxylic acid.

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Section: Methodsmentioning

confidence: 99%

Thermochemical and Theoretical Studies of Dimethylpyridine-2,6-dicarboxylate and Pyridine-2,3-, Pyridine-2,5-, and Pyridine-2,6-dicarboxylic Acids

et al. 2005

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“…The energies of combustion of 1 and 2 were measured with a static bomb calorimeter, with a twin valve bomb and an internal volume of 0.290 dm 3 , assembled originally in Teddington, 19,20 and now installed in Thermochemistry Laboratory, at the University of Porto. 21 The energy equivalent of the calorimeter was determined from the combustion of benzoic acid (BDH Thermochemical Standard, batch 693976/01) having a massic energy of combustion, under standard bomb conditions, of À(26435.1 AE 3.5) J Á g…”

Section: Calorimetric Measurementsmentioning

confidence: 99%

Energetic and structural characterization of 2‐R‐3‐methylquinoxaline‐1,4‐dioxides (R = benzoyl or tert‐butoxycarbonyl): experimental and computational studies

Gomes

Sousa

Gonçalves

et al. 2007

J of Physical Organic Chem

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The gaseous standard molar enthalpies of formation of two 2-R-3-methylquinoxaline-1,4-dioxides (R ¼ benzoyl or tert-butoxycarbonyl), at T ¼ 298.15 K, were derived using the values for the enthalpies of formation of the compounds in the condensed phase, measured by static bomb combustion calorimetry, and for the enthalpies of sublimation, measured by Knudsen effusion, using a quartz crystal oscillator. The three dimensional structure of 2-tert-butoxycarbonyl-3-methylquinoxaline-1,4-dioxide has been obtained by X-ray crystallography showing that the two N-O bond lengths in this compound are identical. The experimentally determined geometry in the crystal is similar to that obtained in the gas-phase after computations performed at the B3LYP/6-311 þ G(2d,2p) level of theory. The experimental and computational results reported allow to extend the discussion about the influence of the molecular structure on the dissociation enthalpy of the N-O bonds for quinoxaline 1,4-dioxide derivatives. As found previously, similar N-O bond lengths in quinoxaline-1,4-dioxide compounds are not linked with N-O bonds having the same strength.

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“…The combustion experiments were performed with a static-bomb calorimeter originally assembled in the National Physical Laboratory, Teddington, U.K. [19] and in the University of Manchester, [20] and now installed in the Thermochemistry Laboratory in the University of Porto, Portugal. [21] The twin valve bomb, with an internal volume of 0.290 dm 3 and wall thickness of 1 cm, is made of stainless steel.…”

Section: Combustion Calorimetrymentioning

confidence: 99%

“…Both the apparatus and the operating technique have been described already in the literature. [19][20][21] The energy equivalent of the calorimeter was determined from the combustion of benzoic acid (NIST Standard Reference Material 39j) with a massic energy of combustion, under standard bomb conditions, of À(26434 AE 3) J Á g À1 . From 11 calibration experiments, e(cal) ¼ (15553.3 AE 0.9) J Á K…”

Section: Combustion Calorimetrymentioning

confidence: 99%

The enthalpies of dissociation of the NO bonds in two quinoxaline derivatives

Gomes

Monteiro

Campos

et al. 2008

J of Physical Organic Chem

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The present work reports the first experimental thermochemical study of mono-N-oxides derived from quinoxaline, namely, 3-methoxycarbonyl-2-methyl-quinoxaline N-oxide and 3-ethoxycarbonyl-2-methyl-quinoxaline N-oxide. The values of the enthalpies of formation, in the condensed state, and of the enthalpies of sublimation, derived from static bomb calorimetry and Calvet microcalorimetry measurements, respectively, are combined to derive the standard molar enthalpies of formation in the gaseous phase for these two compounds. From the latter values, the first and second N-O bond dissociation enthalpies for the corresponding di-N-oxides have been obtained. The gas-phase experimental results are also compared with calculated data obtained with a density functional theory approach.

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Enthalpies of combustion of the three aminopyridines and the three cyanopyridines

Cited by 113 publications

References 13 publications

Thermochemical and Theoretical Studies of Dimethylpyridine-2,6-dicarboxylate and Pyridine-2,3-, Pyridine-2,5-, and Pyridine-2,6-dicarboxylic Acids

Thermochemical and Theoretical Studies of Dimethylpyridine-2,6-dicarboxylate and Pyridine-2,3-, Pyridine-2,5-, and Pyridine-2,6-dicarboxylic Acids

Energetic and structural characterization of 2‐R‐3‐methylquinoxaline‐1,4‐dioxides (R = benzoyl or tert‐butoxycarbonyl): experimental and computational studies

The enthalpies of dissociation of the NO bonds in two quinoxaline derivatives

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