Enthalpies of combustion of the pyridine N-oxide derivatives: 4-methyl-, 3-cyano-, 4-cyano-, 3-hydroxy-, 2-carboxy-, 4-carboxy-, and 3-methyl-4-nitro, and of the pyridine derivatives: 2-carboxy-, and 4-carboxy-. The dissociation enthalpies of the N-O bonds

Silva, Manuel A.V. Ribeiro da; Agostinha, M.; Matos, Rita; Vaz, Maria; Santos, Luı́s M. N. B. F.; Pilcher, G.; Acree, William E.; Powell, Joyce R.

doi:10.1006/jcht.1998.0353

Cited by 46 publications

(24 citation statements)

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“…In terms of Holm's scale, (2) we have r H o m = −(136.1 ± 4.2) kJ · mol −1 for reaction (10) and r H o m = −(35.6 ± 4.8) kJ · mol −1 for reaction (11): 4-nitrosophenol(cr) + 1/2O 2 (g) = 4-nitrophenol(cr),…”

Section: Discussionmentioning

confidence: 99%

Enthalpies of combustion of 2-iodosobenzoic acid and 4-nitrosophenol: the dissociation enthalpy of the I–O bond

Silva

Matos

Ferrão

et al. 1999

The Journal of Chemical Thermodynamics

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Section: Discussionmentioning

confidence: 99%

Enthalpies of combustion of 2-iodosobenzoic acid and 4-nitrosophenol: the dissociation enthalpy of the I–O bond

Silva

Matos

Ferrão

et al. 1999

The Journal of Chemical Thermodynamics

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“…The compound 2-PyCOOCH 3 (CASRN 2459-07-6) was a commercial sample from Aldrich, 99 %. The isomers 3-PyCOOCH 3 (CASRN 93-60-7) and 4-PyCOOCH 3 (CASRN 2459-09-8) were prepared by the esterification of nicotinic acid and isonicotinic acid, respectively, with trimethylorthoacetate according to the published synthetic method of Trujillo and Gopalan. 15 Both products were collected and further purified by fractional distillation under reduced pressure.…”

Section: Methodsmentioning

confidence: 99%

“…The enthalpies of vaporization of 2-PyCOOCH 3 and 4-PyCOOCH 3 were determined in a Calvet high-temperature microcalorimeter (SETARAM HT 1000), using the "vacuum-sublimation drop microcalorimetric method", 25 adapted for liquids. 26 Samples about (6 to 9) mg of the liquid compounds, contained in a thin glass capillary tube sealed at one end, were dropped at room temperature into the hot reaction vessel of a high-temperature Calvet microcalorimeter held at T ) 386 K for 2-PyCOOCH 3 or at T ) 388 K for 4-PyCOOCH 3 and then removed from the hot zone by vacuum evaporation. 27 The microcalorimeter was calibrated in situ using the reported standard molar enthalpies of sublimation of naphthalene 28 and of vaporization of n-decane.…”

Section: Calorimetric Measurementsmentioning

confidence: 99%

“…Both the cooling and heating scans were reproducible after several cycles for the three isomers. The samples were studied over the following temperature ranges: (253 to 303) K for 2-PyCOOCH 3 , (293 to 323) K for 3-PyCOOCH 3 , and (263 to 303) K for 4-PyCOOCH 3 . No solid-solid-phase transitions were observed for the three isomers over these temperature intervals.…”

Section: Calorimetric Measurementsmentioning

confidence: 99%

“…In this context, systematic experimental and theoretical thermochemical studies on heterocyclic molecules derived from pyridine have been done in our Thermochemistry Laboratory for more than a decade in order to evaluate the energetic effects of different substituents on the pyridinic ring. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] The main goal of the present work is to determine the gaseous enthalpies of formation of methyl picolinate (2-PyCOOCH 3 ), methyl nicotinate (3-PyCOOCH 3 ), and methyl isonicotinate (4-PyCOOCH 3 ), represented in Figure 1, together with the measurement of other relevant properties to the thermodynamic characterization of those isomers.…”

Section: Introductionmentioning

confidence: 99%

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Thermodynamic Properties of Three Pyridine Carboxylic Acid Methyl Ester Isomers

et al. 2007

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The present work reports the values of the standard (p°) 0.1 MPa) molar energies of combustion for the liquid isomers methyl picolinate and methyl isonicotinate and for the crystalline isomer methyl nicotinate measured by static bomb calorimetry. The molar enthalpies of vaporization of the three isomers at T ) 298.15 K as well as the molar enthalpies of sublimation of two of them (methyl picolinate and methyl nicotinate) were derived from vapor pressure measurements at different temperatures using a static method. The molar enthalpies of vaporization at T ) 298.15 K of methyl picolinate and methyl isonicotinate were also measured using Calvet microcalorimetry. The thermal behavior of the compounds was studied by differential scanning calorimetry, and the temperatures and the molar enthalpies of fusion were determined using this technique. The experimental results were used to derive the gaseous standard molar enthalpies of formation, at 298.15 K, of the three pyridinecarboxylic acid methyl ester isomers and the triple points of the ortho and meta isomers.

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Thermochemistry and Bond Nature of Oxo and Thio Ligands in Rhenium(V) Catalysts and Rhenium(VII) Intermediates: Density Functional Calculations

Ibdah

Alduwikat

2018

Eur J Inorg Chem

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Models of dithiolate rhenium(V)–oxo and –thio complexes and ReVII (ReVIIO2 and ReVIIOS) intermediates are studied computationally using DFT(B3LYP). The analysis of the Re–E bond (E = O, S) shows that the two lone pairs (Px, Py) on the oxo and thio ligands are strongly polarized to the ReV and ReVII centers, forming partial π bonds, which agree with the bond‐order analysis of 2 (one σ + two partial π bonds). The lone pairs on the thio ligands are less polarized than on the oxo ligand. The ReVO and ReVS bond strengths are calculated to be approximately 163.7 ± 1.8 kcal mol–1 and 123 ± 3 kcal mol–1, respectively. The ReVIIO and ReVIIS bond strengths are calculated to be 118.7 ± 1.2 kcal mol–1 and 80.5 ± 3.5 kcal mol–1, respectively. The calculated oxo– and thio–rhenium bond strengths and the thermochemistry of the OAT (oxygen‐atom transfer) cycle support that ReVIIO2 and ReVIIOS are the key intermediates in the OAT (oxygen atom transfer) and SAT (sulfur atom transfer) reactions.

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Enthalpies of combustion of the pyridine N-oxide derivatives: 4-methyl-, 3-cyano-, 4-cyano-, 3-hydroxy-, 2-carboxy-, 4-carboxy-, and 3-methyl-4-nitro, and of the pyridine derivatives: 2-carboxy-, and 4-carboxy-. The dissociation enthalpies of the N-O bonds

Cited by 46 publications

References 0 publications

Enthalpies of combustion of 2-iodosobenzoic acid and 4-nitrosophenol: the dissociation enthalpy of the I–O bond

Enthalpies of combustion of 2-iodosobenzoic acid and 4-nitrosophenol: the dissociation enthalpy of the I–O bond

Thermodynamic Properties of Three Pyridine Carboxylic Acid Methyl Ester Isomers

Thermochemistry and Bond Nature of Oxo and Thio Ligands in Rhenium(V) Catalysts and Rhenium(VII) Intermediates: Density Functional Calculations

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