Thermochemical study of arene carboxylic acids

Roux, Marı́a Victoria; Jiménez, Pilar; Notario, Rafael; Temprado, Manuel; Martín-Valcarcel, Gloria; Liebman, Joel F.

doi:10.3998/ark.5550190.0006.931

Cited by 6 publications

(16 citation statements)

References 8 publications

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“…In our work, we showed that 3-thiophenecarboxylic acid is slightly more stable, thermodynamically, than 2-thiophenecarboxylic acid with an isomerization enthalpy of 2.6 kJ‚mol -1 . In the comparison with benzene and its analogous substituted benzene, benzoic acid, we showed that the 2-isomer is destabilized by 2.4 kJ‚mol -1 as a result of the through-space interaction between the oxygen of the hydroxyl group with the sulfur atom, 16 as opposed to stabilization because of an S‚‚‚H‚‚‚O hydrogen bond. With the result obtained with 3-thiophenecarboxylic acid, -0.2 kJ‚mol -1 , we concluded that there are not significant differences between the substituent effects produced by a carboxyl group in benzene and the 3-position in thiophene.…”

Section: Introductionmentioning

confidence: 93%

“…Over the past years, we have been involved in a thermochemical study of the energetic effects of sulfur compounds, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] among them thiophene derivatives. 6,9,16,17 The fundamental interest in this work is the understanding of structural effects on thermodynamic stabilities that are reflected on the enthalpies of formation for the compounds studied.…”

Section: Introductionmentioning

confidence: 99%

“…With the result obtained with 3-thiophenecarboxylic acid, -0.2 kJ‚mol -1 , we concluded that there are not significant differences between the substituent effects produced by a carboxyl group in benzene and the 3-position in thiophene. 16 The purpose of this work is to study the energetic effects of 2,5-thiophenedicarboxylic acid (2,5-dicarboxythiophene) and its relationship with thiophene and 2-thiophenecarboxylic acid. Furthermore, a comparison with the analogous benzene derivatives (benzene, benzoic acid, and 1,4-benzenedicarboxylic acid) has been carried out.…”

Section: Introductionmentioning

confidence: 99%

“…Over the past years, we have been involved in a thermochemical study of the energetic effects of sulfur compounds, − among them thiophene derivatives. ,,, The fundamental interest in this work is the understanding of structural effects on thermodynamic stabilities that are reflected on the enthalpies of formation for the compounds studied. If benzenes are the paradigm of aromatic molecules, thiophenes are the simplest representatives of stable aromatic structures bearing sulfur…”

Section: Introductionmentioning

confidence: 99%

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Thermochemistry of 2,5-Thiophenedicarboxylic Acid

et al. 2006

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The enthalpies of combustion and sublimation of 2,5-thiophenedicarboxylic acid [CASRN 4282-31-9] were measured by rotary-bomb combustion calorimetry and the method of transference in a saturated stream of nitrogen, and the gas-phase enthalpy of formation was determined, Delta(f)H(o)(m)(g) = -(632.6 +/- 2.2) kJ x mol(-1). Standard ab initio molecular orbital calculations at the G2(MP2) and G3(MP2) levels were performed, and a theoretical study on the molecular and electronic structure of the compound has been carried out. The three most stable conformers have been explicitly taken into account. The calculated enthalpy of formation averaged using three different isodesmic reactions, -631.1 kJ x mol(-1), is in very good agreement with the experimental value. A comparison of the substituent effect of the carboxylic groups in benzene and thiophene ring has been made. The relative stability obtained for the substitution of two H atoms by COOH in position 2,5- for thiophene and 1,4- for benzene involve the same energetic effects, DeltaDelta(f)H(o)(m)= -747.6 +/- 2.4 and -748.2 +/- 2.7 kJ x mol(-1), respectively.

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Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Thermochemistry of 2,5-Thiophenedicarboxylic Acid

et al. 2006

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“…In recent years, we have been involved in a thermochemical study of the energetics of thiophene derivatives. − A development of an understanding of the structural effects on thermodynamic stabilities reflected in the gas-phase enthalpies of formation of the compounds studied has been of fundamental interest to us. Substituents on the five-membered ring of thiophene have a different relationship to one another than similar substituents in benzene.…”

Section: Introductionmentioning

confidence: 99%

Thermochemistry of 2- and 3-Acetylthiophenes: Calorimetric and Computational Study

Roux¹,

Temprado²,

Jiménez³

et al. 2007

J. Phys. Chem. A

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The relative stabilities of 2- and 3-acetylthiophenes have been evaluated by experimental thermochemistry and the results compared to high-level ab initio calculations. The enthalpies of combustion, vaporization, and sublimation were measured by rotating-bomb combustion calorimetry, Calvet microcalorimetry, correlation gas chromatography, and Knudsen effusion techniques and the gas-phase enthalpies of formation, at T = 298.15 K, were determined. Standard ab initio molecular orbital calculations at the G2 and G3 levels were performed, and a theoretical study on the molecular and electronic structures of the compounds studied has been conducted. Calculated enthalpies of formation using atomization and isodesmic reactions are compared with the experimental data. Experimental and theoretical results show that 2-acetylthiophene is thermodynamically more stable than the 3-isomer. A comparison of the substituent effect of the acetyl group in benzene and thiophene rings has been carried out.

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