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Papers by Henoc Flores
The Journal of Chemical Thermodynamics, 2020
Abstract In the present work, a detailed thermochemical, experimental and theoretical, study of b... more Abstract In the present work, a detailed thermochemical, experimental and theoretical, study of benzocaine is presented. The enthalpy of formation in crystalline state at T = 298.15 K was obtained from combustion calorimetry experiments [ Δ f H m ° c r = - 415.2 ± 1.7 k J ∙ m o l - 1 ], within an oxygen atmosphere, using a static bomb calorimeter. The phase transition enthalpies (fusion, vaporization, and sublimation) were obtained by different techniques, namely differential scanning calorimetry, Calvet microcalorimetry, thermogravimetry, and the Knudsen effusion method. The results obtained by the different techniques are as follows: Δ cr l H m ° 298.15 K = 21.4 ± 0.1 kJ⋅mol−1; Δ l g H m ° 298.15 K = 84.9 ± 1.0 kJ⋅mol−1; Δ cr g H m ° 298.15 K = 106.8 ± 0.4 kJ⋅mol−1. From the experimental results, the enthalpy of formation of the aforesaid compound, in the gas phase, was calculated at T = 298.15 K as: Δ f H m ° g = - 308.4 ± 1.8 k J ∙ m o l - 1 . Theoretical enthalpies were computed using the Gaussian G4 composite method, atomization reactions, and the weighted Boltzmann average method. For the latter, the conformational diversity of the molecular structure of the compound was considered. Using the above data and using a similar approach, the theoretical entropy of benzocaine was computed as well. The experimental and theoretical values obtained were compared and an excellent accordance was found. Using the experimental and theoretical results, Gibbs energy of formation in crystalline and gaseous states of benzocaine, at T = 298.15 K were calculated as: Δ f G m ° c r = - 164.4 k J ∙ m o l - 1 and Δ f G m ° g = - 123.9 k J ∙ m o l - 1 , respectively. Finally, the results obtained from the enthalpies of phase change are compared with those previously reported in the literature, in order to propose an exact value for these properties.
Journal of Chemical & Engineering Data
The sublimation enthalpies of some hydroxyflavones and one amineflavone were determined with a th... more The sublimation enthalpies of some hydroxyflavones and one amineflavone were determined with a thermogravimetric device under isothermal conditions. These enthalpies were obtained by measuring the rate of mass loss as a function of temperature. In this methodology, the Clausius–Clapeyron and Langmuir equations were used. The diffusional effect of the gas phase was included in the Langmuir equation. In order to test and validate the experimental methodology, the sublimation enthalpy of three standard materials, anthracene, pyrene, and benzoic acid, were determined. The values obtained are in agreement with the data reported and recommended in the literature. Low uncertainties were obtained in all thermogravimetric measurements. Additionally, by differential scanning calorimetry, the molar fraction, temperature and enthalpy of fusion, and heat capacity of the solid phase were determined for all of the compounds studied. The heat capacities of the gas phase were estimated using computational methods. Isother...
Structural Chemistry, 2017
Calorimetry provides an accurate and reliable method to determine the enthalpies of formation of ... more Calorimetry provides an accurate and reliable method to determine the enthalpies of formation of organic molecules in the gas phase. From the experimental formation enthalpies and the absolute entropies, obtained by theoretical calculations, it is possible to perform Gibbs energy calculations. This thermodynamic function is widely used to describe various thermodynamic processes, such as chemical equilibrium, and allows the calculation of equilibrium constants. The specific standard combustion energies of 3,5-dimethylisoxazole-4-carboxylic acid, 5-methylisoxazole-3-carboxylic acid, 5-amino-3-methylisoxazole, and 3-amino-5-methylisoxazole were determined by using a combustion calorimeter. The sublimation enthalpies of the compounds were determined by means of the Knudsen effusion technique. From these values, the molar standard enthalpy of formation in gaseous phase of each compound was calculated. Theoretical calculations at the G3 and G4 levels were performed, and a study of the molecular and electronic structure of these compounds was carried out. The calculated enthalpies of formation are in very good agreement with the experimental values. From both the experimental and theoretical results, five gas phase chemical equilibria were studied: one of isomerization, two of CO2 loss, and two of NH3 loss. The equilibrium constants for each process were calculated, which allow prediction of the direction of the chemical process from a thermodynamic viewpoint.
The Journal of …, 1999
To understand the relative isomeric stabilities of 1, 3-and 1, 4-diheterocyclohexanes and the ult... more To understand the relative isomeric stabilities of 1, 3-and 1, 4-diheterocyclohexanes and the ultradiagonal strain energy of thiirane, the enthalpies of formation and sublimation of 1, 4-dithiane have been measured. The enthalpy of formation for this compound in the solid ...
The Journal of Chemical Thermodynamics, 2016
Thermochimica Acta, Nov 1, 2006
The enthalpies of combustion of 3-formylchromone (3F), 3-formyl-6-methylchromone (3F6M) and 3-for... more The enthalpies of combustion of 3-formylchromone (3F), 3-formyl-6-methylchromone (3F6M) and 3-formyl-6-isopropylchromone (3F6I) were determined by combustion calorimetry. The molar combustion energies ( c U 0 m (cr, 298.15 K)) of the 3F, 3F6M and 3F6I are: −(4452.4 ± 1.8), −(5115.6 ± 2.7) and −(6411.4 ± 2.5) kJ mol −1 , respectively. The formation enthalpies in the crystalline state ( f H • m (cr, 298.15 K)) are: −(340.2 ± 2.2), −(355.1 ± 3.1) and −(415.5 ± 3.0) kJ mol −1 , respectively.s
The Journal of Chemical Thermodynamics, 2016
The Journal of Chemical Thermodynamics, Mar 1, 2010
The Journal of Chemical Thermodynamics, May 31, 2008
The standard molar energies of combustion, D c U m ðcr; 298:15 KÞ, of a-D-glucoheptono-1,4-lacton... more The standard molar energies of combustion, D c U m ðcr; 298:15 KÞ, of a-D-glucoheptono-1,4-lactone (GH) and a,b-glucooctanoic-1,4-lactone (GO) were obtained by micro-combustion calorimetry. The obtained values are À(2924.6 ± 2.3) kJ Á mol À1 and À(3459.5 ± 2.5) kJ Á mol À1 , respectively. From combustion energies, the standard molar enthalpies of formation in crystalline phase, D f H m ðcr; 298:15 KÞ, for GH and GO were determined as À(1546.2 ± 2.5) kJ Á mol À1 and À(1690.6 ± 2.7) kJ Á mol À1 , respectively. Also it was found that when the hydroxyl group number increases in the aldonolactones their standard molar enthalpies of formation increase too.
Journal of Thermal Analysis and Calorimetry, 2015
Acta Crystallographica Section E-structure Reports Online, 2007
The Journal of Chemical Thermodynamics, 2011
The standard molar energies of combustion, ΔcUm∘ (cr, 298.15K) of 7-hydroxy-4-methylcoumarin, 7-e... more The standard molar energies of combustion, ΔcUm∘ (cr, 298.15K) of 7-hydroxy-4-methylcoumarin, 7-ethoxy-4-methylcoumarin, and 6-methoxy-4-methylcoumarin were obtained by combustion calorimetry. The experimental values are (−4536.4±2.2), (−5888.0±3.2), and (−5267.3±2.3)kJ·mol−1, respectively. From these values, the standard molar enthalpies of formation in the crystalline phase were calculated and found to be (−540.8±2.6), (−545.4±3.6), and (−488.0±2.7)kJ·mol−1, respectively.
The Journal of Chemical Thermodynamics, 2012
ABSTRACT The energies of combustion of benzenesulfonamide (cr), o-toluenesulfonamide (cr), p-tolu... more ABSTRACT The energies of combustion of benzenesulfonamide (cr), o-toluenesulfonamide (cr), p-toluenesulfonamide (cr), 2-aminobenzenesulfonamide (cr), and 4-aminobenzenesulfonamide were determined using a combustion rotating-bomb calorimeter. The molar energies of combustion for these compounds in the condensed phase at T = 298.15 K were determined as: −(3611.4 ± 1.8) kJ · mol−1, −(4280.7 ± 1.1) kJ · mol−1, −(4458.8 ± 1.5) kJ · mol−1, −(3745.7 ± 1.2) kJ · mol−1 and −(3725.6 ± 1.9) kJ · mol−1, respectively. From these values, corresponding standard molar enthalpies of formation were obtained as: −(347.1 ± 1.9) kJ · mol−1, −(356.5 ± 1.4) kJ · mol−1, −(178.4 ± 1.7) kJ · mol−1, −(356.9 ± 1.4) kJ · mol−1 and −(377.1 ± 2.1) kJ · mol−1, respectively. A differential scanning calorimeter was used to determine the purities and heat capacities of the compounds studied here. Polyethene bags were used as a combustion auxiliary in the combustion experiments.
The Journal of Chemical Thermodynamics, 2014
ABSTRACT The standard molar energies of combustion of 2-nitrobenzamide, 3-nitrobenzamide and 4-ni... more ABSTRACT The standard molar energies of combustion of 2-nitrobenzamide, 3-nitrobenzamide and 4-nitrobenzamide were determined with an isoperibolic, static-bomb, combustion calorimeter. From the combustion results, the standard molar enthalpies of combustion and formation for these compounds in the condensed phase at T = 298.15 K were derived. Subsequently, to determine the enthalpies of sublimation, the vapour pressure data as a function of the temperature for the compounds under investigation were estimated using thermogravimetry by applying Langmuir's equation, and the enthalpies of vaporisation were derived. Standard enthalpies of fusion were measured by differential scanning calorimetry then added to those of vaporisation to obtain reliable results for the enthalpy of sublimation. From the combustion and sublimation data, the gas phase enthalpies of formation were determined to be (-138.9 +/- 3.5) kJ . mol (1), (-122.9 +/- 2.9) kJ . mol (1) and (-108.5 +/- 3.7) kJ . mol (1) for the ortho, meta and para isomers of nitrobenzamide, respectively. The meaning of these results with regard to the enthalpic stability of these molecular structures is discussed herein.
Thermochimica Acta, 2006
The enthalpies of combustion of 3-formylchromone (3F), 3-formyl-6-methylchromone (3F6M) and 3-for... more The enthalpies of combustion of 3-formylchromone (3F), 3-formyl-6-methylchromone (3F6M) and 3-formyl-6-isopropylchromone (3F6I) were determined by combustion calorimetry. The molar combustion energies ( c U 0 m (cr, 298.15 K)) of the 3F, 3F6M and 3F6I are: −(4452.4 ± 1.8), −(5115.6 ± 2.7) and −(6411.4 ± 2.5) kJ mol −1 , respectively. The formation enthalpies in the crystalline state ( f H • m (cr, 298.15 K)) are: −(340.2 ± 2.2), −(355.1 ± 3.1) and −(415.5 ± 3.0) kJ mol −1 , respectively.s
The Journal of Chemical Thermodynamics, 2006
... Aside to the bath, a sluice R is provided to exclude a convenient volume of water in order to... more ... Aside to the bath, a sluice R is provided to exclude a convenient volume of water in order to place or remove the internal vessel. ... Both, the thermostatic bath and sluice are placed into a wooden box T which has a switchboard U. 3. Experimental procedure. ...
Thermochimica Acta, 2009
The combustion energies for 2-acetylpyrrole (cr) and 2-acetylfuran (cr) were determined using a s... more The combustion energies for 2-acetylpyrrole (cr) and 2-acetylfuran (cr) were determined using a static bomb calorimeter, whereas the combustion energy of 2-acetylthiophene (l) was determined with a rotating bomb calorimeter; both calorimeters have been recently described. The molar combustion energies obtained were: −(3196.1 ± 0.6) kJ mol −1 for 2-acetylpyrrole, −(2933.8 ± 0.7) kJ mol −1 for 2-acetylfuran, and −(3690.4 ± 0.8) kJ mol −1 for 2-acetylthiophene. From these combustion energy values, the standard molar enthalpies of formation in the condensate phase were obtained as: −(163.51 ± 0.97) kJ mol −1 , −(283.50 ± 1.06) kJ mol −1 and −(123.93 ± 1.15) kJ mol −1 , respectively. The obtained values of combustion and formation enthalpies of 2-acetylthiophene are in concordance with the reported previously. For the two last compounds, polyethene bags were used as an auxiliary material in the combustion experiments. The heat capacities and purities of the compounds were determined using a differential scanning calorimeter.
The Journal of Chemical Thermodynamics, 2014
2-Aminobenzothiazole 2-Amino-4-methyl-benzothiazole 2-Amino-6-methyl-benzothiazole Enthalpies of ... more 2-Aminobenzothiazole 2-Amino-4-methyl-benzothiazole 2-Amino-6-methyl-benzothiazole Enthalpies of formation in the gas phase Gausian-4 theory a b s t r a c t
The Journal of Chemical Thermodynamics, 2012
Standard energies of combustion of ricinoleic acid and methyl ricinoleate were measured experimen... more Standard energies of combustion of ricinoleic acid and methyl ricinoleate were measured experimentally by using a semi-micro bomb calorimeter. The energies of combustion of ricinoleic acid and methyl ricinoleate were used to derive the corresponding standard molar enthalpies of formation ðÀD f H m Þ in liquid phase at T = 298.15 K. The values of ÀD f H m for these compounds are (À1097.7 ± 11.6) kJ Á mol À1 and (À1027.1 ± 12.4) kJ Á mol À1 , respectively.
The Journal of Chemical Thermodynamics, 2008
The standard molar energies of combustion, D c U m ðcr; 298:15 KÞ, of a-D-glucoheptono-1,4-lacton... more The standard molar energies of combustion, D c U m ðcr; 298:15 KÞ, of a-D-glucoheptono-1,4-lactone (GH) and a,b-glucooctanoic-1,4-lactone (GO) were obtained by micro-combustion calorimetry. The obtained values are À(2924.6 ± 2.3) kJ Á mol À1 and À(3459.5 ± 2.5) kJ Á mol À1 , respectively. From combustion energies, the standard molar enthalpies of formation in crystalline phase, D f H m ðcr; 298:15 KÞ, for GH and GO were determined as À(1546.2 ± 2.5) kJ Á mol À1 and À(1690.6 ± 2.7) kJ Á mol À1 , respectively. Also it was found that when the hydroxyl group number increases in the aldonolactones their standard molar enthalpies of formation increase too.
The Journal of Chemical Thermodynamics, 2020
Abstract In the present work, a detailed thermochemical, experimental and theoretical, study of b... more Abstract In the present work, a detailed thermochemical, experimental and theoretical, study of benzocaine is presented. The enthalpy of formation in crystalline state at T = 298.15 K was obtained from combustion calorimetry experiments [ Δ f H m ° c r = - 415.2 ± 1.7 k J ∙ m o l - 1 ], within an oxygen atmosphere, using a static bomb calorimeter. The phase transition enthalpies (fusion, vaporization, and sublimation) were obtained by different techniques, namely differential scanning calorimetry, Calvet microcalorimetry, thermogravimetry, and the Knudsen effusion method. The results obtained by the different techniques are as follows: Δ cr l H m ° 298.15 K = 21.4 ± 0.1 kJ⋅mol−1; Δ l g H m ° 298.15 K = 84.9 ± 1.0 kJ⋅mol−1; Δ cr g H m ° 298.15 K = 106.8 ± 0.4 kJ⋅mol−1. From the experimental results, the enthalpy of formation of the aforesaid compound, in the gas phase, was calculated at T = 298.15 K as: Δ f H m ° g = - 308.4 ± 1.8 k J ∙ m o l - 1 . Theoretical enthalpies were computed using the Gaussian G4 composite method, atomization reactions, and the weighted Boltzmann average method. For the latter, the conformational diversity of the molecular structure of the compound was considered. Using the above data and using a similar approach, the theoretical entropy of benzocaine was computed as well. The experimental and theoretical values obtained were compared and an excellent accordance was found. Using the experimental and theoretical results, Gibbs energy of formation in crystalline and gaseous states of benzocaine, at T = 298.15 K were calculated as: Δ f G m ° c r = - 164.4 k J ∙ m o l - 1 and Δ f G m ° g = - 123.9 k J ∙ m o l - 1 , respectively. Finally, the results obtained from the enthalpies of phase change are compared with those previously reported in the literature, in order to propose an exact value for these properties.
Journal of Chemical & Engineering Data
The sublimation enthalpies of some hydroxyflavones and one amineflavone were determined with a th... more The sublimation enthalpies of some hydroxyflavones and one amineflavone were determined with a thermogravimetric device under isothermal conditions. These enthalpies were obtained by measuring the rate of mass loss as a function of temperature. In this methodology, the Clausius–Clapeyron and Langmuir equations were used. The diffusional effect of the gas phase was included in the Langmuir equation. In order to test and validate the experimental methodology, the sublimation enthalpy of three standard materials, anthracene, pyrene, and benzoic acid, were determined. The values obtained are in agreement with the data reported and recommended in the literature. Low uncertainties were obtained in all thermogravimetric measurements. Additionally, by differential scanning calorimetry, the molar fraction, temperature and enthalpy of fusion, and heat capacity of the solid phase were determined for all of the compounds studied. The heat capacities of the gas phase were estimated using computational methods. Isother...
Structural Chemistry, 2017
Calorimetry provides an accurate and reliable method to determine the enthalpies of formation of ... more Calorimetry provides an accurate and reliable method to determine the enthalpies of formation of organic molecules in the gas phase. From the experimental formation enthalpies and the absolute entropies, obtained by theoretical calculations, it is possible to perform Gibbs energy calculations. This thermodynamic function is widely used to describe various thermodynamic processes, such as chemical equilibrium, and allows the calculation of equilibrium constants. The specific standard combustion energies of 3,5-dimethylisoxazole-4-carboxylic acid, 5-methylisoxazole-3-carboxylic acid, 5-amino-3-methylisoxazole, and 3-amino-5-methylisoxazole were determined by using a combustion calorimeter. The sublimation enthalpies of the compounds were determined by means of the Knudsen effusion technique. From these values, the molar standard enthalpy of formation in gaseous phase of each compound was calculated. Theoretical calculations at the G3 and G4 levels were performed, and a study of the molecular and electronic structure of these compounds was carried out. The calculated enthalpies of formation are in very good agreement with the experimental values. From both the experimental and theoretical results, five gas phase chemical equilibria were studied: one of isomerization, two of CO2 loss, and two of NH3 loss. The equilibrium constants for each process were calculated, which allow prediction of the direction of the chemical process from a thermodynamic viewpoint.
The Journal of …, 1999
To understand the relative isomeric stabilities of 1, 3-and 1, 4-diheterocyclohexanes and the ult... more To understand the relative isomeric stabilities of 1, 3-and 1, 4-diheterocyclohexanes and the ultradiagonal strain energy of thiirane, the enthalpies of formation and sublimation of 1, 4-dithiane have been measured. The enthalpy of formation for this compound in the solid ...
The Journal of Chemical Thermodynamics, 2016
Thermochimica Acta, Nov 1, 2006
The enthalpies of combustion of 3-formylchromone (3F), 3-formyl-6-methylchromone (3F6M) and 3-for... more The enthalpies of combustion of 3-formylchromone (3F), 3-formyl-6-methylchromone (3F6M) and 3-formyl-6-isopropylchromone (3F6I) were determined by combustion calorimetry. The molar combustion energies ( c U 0 m (cr, 298.15 K)) of the 3F, 3F6M and 3F6I are: −(4452.4 ± 1.8), −(5115.6 ± 2.7) and −(6411.4 ± 2.5) kJ mol −1 , respectively. The formation enthalpies in the crystalline state ( f H • m (cr, 298.15 K)) are: −(340.2 ± 2.2), −(355.1 ± 3.1) and −(415.5 ± 3.0) kJ mol −1 , respectively.s
The Journal of Chemical Thermodynamics, 2016
The Journal of Chemical Thermodynamics, Mar 1, 2010
The Journal of Chemical Thermodynamics, May 31, 2008
The standard molar energies of combustion, D c U m ðcr; 298:15 KÞ, of a-D-glucoheptono-1,4-lacton... more The standard molar energies of combustion, D c U m ðcr; 298:15 KÞ, of a-D-glucoheptono-1,4-lactone (GH) and a,b-glucooctanoic-1,4-lactone (GO) were obtained by micro-combustion calorimetry. The obtained values are À(2924.6 ± 2.3) kJ Á mol À1 and À(3459.5 ± 2.5) kJ Á mol À1 , respectively. From combustion energies, the standard molar enthalpies of formation in crystalline phase, D f H m ðcr; 298:15 KÞ, for GH and GO were determined as À(1546.2 ± 2.5) kJ Á mol À1 and À(1690.6 ± 2.7) kJ Á mol À1 , respectively. Also it was found that when the hydroxyl group number increases in the aldonolactones their standard molar enthalpies of formation increase too.
Journal of Thermal Analysis and Calorimetry, 2015
Acta Crystallographica Section E-structure Reports Online, 2007
The Journal of Chemical Thermodynamics, 2011
The standard molar energies of combustion, ΔcUm∘ (cr, 298.15K) of 7-hydroxy-4-methylcoumarin, 7-e... more The standard molar energies of combustion, ΔcUm∘ (cr, 298.15K) of 7-hydroxy-4-methylcoumarin, 7-ethoxy-4-methylcoumarin, and 6-methoxy-4-methylcoumarin were obtained by combustion calorimetry. The experimental values are (−4536.4±2.2), (−5888.0±3.2), and (−5267.3±2.3)kJ·mol−1, respectively. From these values, the standard molar enthalpies of formation in the crystalline phase were calculated and found to be (−540.8±2.6), (−545.4±3.6), and (−488.0±2.7)kJ·mol−1, respectively.
The Journal of Chemical Thermodynamics, 2012
ABSTRACT The energies of combustion of benzenesulfonamide (cr), o-toluenesulfonamide (cr), p-tolu... more ABSTRACT The energies of combustion of benzenesulfonamide (cr), o-toluenesulfonamide (cr), p-toluenesulfonamide (cr), 2-aminobenzenesulfonamide (cr), and 4-aminobenzenesulfonamide were determined using a combustion rotating-bomb calorimeter. The molar energies of combustion for these compounds in the condensed phase at T = 298.15 K were determined as: −(3611.4 ± 1.8) kJ · mol−1, −(4280.7 ± 1.1) kJ · mol−1, −(4458.8 ± 1.5) kJ · mol−1, −(3745.7 ± 1.2) kJ · mol−1 and −(3725.6 ± 1.9) kJ · mol−1, respectively. From these values, corresponding standard molar enthalpies of formation were obtained as: −(347.1 ± 1.9) kJ · mol−1, −(356.5 ± 1.4) kJ · mol−1, −(178.4 ± 1.7) kJ · mol−1, −(356.9 ± 1.4) kJ · mol−1 and −(377.1 ± 2.1) kJ · mol−1, respectively. A differential scanning calorimeter was used to determine the purities and heat capacities of the compounds studied here. Polyethene bags were used as a combustion auxiliary in the combustion experiments.
The Journal of Chemical Thermodynamics, 2014
ABSTRACT The standard molar energies of combustion of 2-nitrobenzamide, 3-nitrobenzamide and 4-ni... more ABSTRACT The standard molar energies of combustion of 2-nitrobenzamide, 3-nitrobenzamide and 4-nitrobenzamide were determined with an isoperibolic, static-bomb, combustion calorimeter. From the combustion results, the standard molar enthalpies of combustion and formation for these compounds in the condensed phase at T = 298.15 K were derived. Subsequently, to determine the enthalpies of sublimation, the vapour pressure data as a function of the temperature for the compounds under investigation were estimated using thermogravimetry by applying Langmuir's equation, and the enthalpies of vaporisation were derived. Standard enthalpies of fusion were measured by differential scanning calorimetry then added to those of vaporisation to obtain reliable results for the enthalpy of sublimation. From the combustion and sublimation data, the gas phase enthalpies of formation were determined to be (-138.9 +/- 3.5) kJ . mol (1), (-122.9 +/- 2.9) kJ . mol (1) and (-108.5 +/- 3.7) kJ . mol (1) for the ortho, meta and para isomers of nitrobenzamide, respectively. The meaning of these results with regard to the enthalpic stability of these molecular structures is discussed herein.
Thermochimica Acta, 2006
The enthalpies of combustion of 3-formylchromone (3F), 3-formyl-6-methylchromone (3F6M) and 3-for... more The enthalpies of combustion of 3-formylchromone (3F), 3-formyl-6-methylchromone (3F6M) and 3-formyl-6-isopropylchromone (3F6I) were determined by combustion calorimetry. The molar combustion energies ( c U 0 m (cr, 298.15 K)) of the 3F, 3F6M and 3F6I are: −(4452.4 ± 1.8), −(5115.6 ± 2.7) and −(6411.4 ± 2.5) kJ mol −1 , respectively. The formation enthalpies in the crystalline state ( f H • m (cr, 298.15 K)) are: −(340.2 ± 2.2), −(355.1 ± 3.1) and −(415.5 ± 3.0) kJ mol −1 , respectively.s
The Journal of Chemical Thermodynamics, 2006
... Aside to the bath, a sluice R is provided to exclude a convenient volume of water in order to... more ... Aside to the bath, a sluice R is provided to exclude a convenient volume of water in order to place or remove the internal vessel. ... Both, the thermostatic bath and sluice are placed into a wooden box T which has a switchboard U. 3. Experimental procedure. ...
Thermochimica Acta, 2009
The combustion energies for 2-acetylpyrrole (cr) and 2-acetylfuran (cr) were determined using a s... more The combustion energies for 2-acetylpyrrole (cr) and 2-acetylfuran (cr) were determined using a static bomb calorimeter, whereas the combustion energy of 2-acetylthiophene (l) was determined with a rotating bomb calorimeter; both calorimeters have been recently described. The molar combustion energies obtained were: −(3196.1 ± 0.6) kJ mol −1 for 2-acetylpyrrole, −(2933.8 ± 0.7) kJ mol −1 for 2-acetylfuran, and −(3690.4 ± 0.8) kJ mol −1 for 2-acetylthiophene. From these combustion energy values, the standard molar enthalpies of formation in the condensate phase were obtained as: −(163.51 ± 0.97) kJ mol −1 , −(283.50 ± 1.06) kJ mol −1 and −(123.93 ± 1.15) kJ mol −1 , respectively. The obtained values of combustion and formation enthalpies of 2-acetylthiophene are in concordance with the reported previously. For the two last compounds, polyethene bags were used as an auxiliary material in the combustion experiments. The heat capacities and purities of the compounds were determined using a differential scanning calorimeter.
The Journal of Chemical Thermodynamics, 2014
2-Aminobenzothiazole 2-Amino-4-methyl-benzothiazole 2-Amino-6-methyl-benzothiazole Enthalpies of ... more 2-Aminobenzothiazole 2-Amino-4-methyl-benzothiazole 2-Amino-6-methyl-benzothiazole Enthalpies of formation in the gas phase Gausian-4 theory a b s t r a c t
The Journal of Chemical Thermodynamics, 2012
Standard energies of combustion of ricinoleic acid and methyl ricinoleate were measured experimen... more Standard energies of combustion of ricinoleic acid and methyl ricinoleate were measured experimentally by using a semi-micro bomb calorimeter. The energies of combustion of ricinoleic acid and methyl ricinoleate were used to derive the corresponding standard molar enthalpies of formation ðÀD f H m Þ in liquid phase at T = 298.15 K. The values of ÀD f H m for these compounds are (À1097.7 ± 11.6) kJ Á mol À1 and (À1027.1 ± 12.4) kJ Á mol À1 , respectively.
The Journal of Chemical Thermodynamics, 2008
The standard molar energies of combustion, D c U m ðcr; 298:15 KÞ, of a-D-glucoheptono-1,4-lacton... more The standard molar energies of combustion, D c U m ðcr; 298:15 KÞ, of a-D-glucoheptono-1,4-lactone (GH) and a,b-glucooctanoic-1,4-lactone (GO) were obtained by micro-combustion calorimetry. The obtained values are À(2924.6 ± 2.3) kJ Á mol À1 and À(3459.5 ± 2.5) kJ Á mol À1 , respectively. From combustion energies, the standard molar enthalpies of formation in crystalline phase, D f H m ðcr; 298:15 KÞ, for GH and GO were determined as À(1546.2 ± 2.5) kJ Á mol À1 and À(1690.6 ± 2.7) kJ Á mol À1 , respectively. Also it was found that when the hydroxyl group number increases in the aldonolactones their standard molar enthalpies of formation increase too.