Étude thermodynamique des acides phtalique, isophtalique et téréphtalique

1999 ◽  
Vol 77 (9) ◽  
pp. 1508-1513 ◽  
Author(s):  
Raphaël Sabbah ◽  
Laurence Perez
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Resonance Energy ◽  
Intermolecular Forces ◽  
Enthalpies Of Formation ◽  
Enthalpy Of Sublimation ◽  
Gaseous State ◽  
Combustion Enthalpy ◽  
The One ◽  
Triple Point Temperature

A thermodynamic study of phthalic, isophthalic, and terephthalic acids (general formula: C8H6O4) was carried out by sublimation calorimetry and differential thermal analysis. With values of combustion enthalpy taken from the literature, it was possible to determine their enthalpies of formation in the gaseous state and at 298.15 K and their resonance energy. The results enabled us to do a comparative study of the relative stability of the three acids, on the one hand, and of different benzene disubstituted derivatives, on the other hand. From the enthalpy of sublimation, it was possible to determine the energetic contribution of the different intermolecular forces in the crystals of the three acids.Key words: thermodynamic, calorimetry, differential thermal analysis, phthalic, isophthalic, terephthalic acids, enthalpy of fusion, of sublimation, of formation, of intermolecular bonds, resonance energy, triple point temperature.

Energétique des liaisons inter et intramoléculaires dans les trois isomères de l'aminophénol

1996 ◽  
Vol 74 (4) ◽  
pp. 500-507 ◽  
Author(s):  
Raphaël Sabbah ◽  
Meriem Gouali
Keyword(s):  
Thermal Analysis ◽  
Hydrogen Bond ◽  
Differential Thermal Analysis ◽  
Resonance Energy ◽  
Enthalpy Of Combustion ◽  
Atomization Enthalpy ◽  
Resonance Energies ◽  
Heat Capacity Measurements ◽  
Intramolecular Hydrogen ◽  
Triple Point Temperature

The prsesent work is concerned with a thermodynamic study of the three aminophenol isomers (general formula: C6H7NO). It was achieved using four techniques: combustion calorimetry of small amounts of substance (a few milligrams), sublimation calorimetry, differential thermal analysis, and heat capacity measurements. From this study, it was possible: to determine the enthalpies of combustion, sublimation, and fusion of these compounds; to discuss the relative stability of the three molecules; to determine the intermolecular enthalpy bonds; to determine the experimental resonance energies and to compare them with the theoretical values; to determine the atomization enthalpies and to compare them with the values calculated from the energetical contributions previously determined in our laboratory; to consider the existence of an intramolecular hydrogen bond in the ortho isomer. Key words: thermodynamics; thermochemistry; calorimetry; differential thermal analysis; 2-aminophenol or ortho-aminophenol; 3-aminophenol or meta-aminophenol; 4-aminophenol or para-aminophenol; enthalpy of combustion, of sublimation, of fusion, of atomization, enthalpy of inter and intramolecular bonds; hydrogen bond; resonance energy; triple point temperature.

Étude thermodynamique de l'acridone et de la thioxanthone

1992 ◽  
Vol 70 (1) ◽  
pp. 24-28 ◽  
Author(s):  
Raphaël Sabbah ◽  
Lahcen El Watik
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Resonance Energy ◽  
Experimental Result ◽  
Thermodynamic Quantities ◽  
A Value ◽  
Experimental Enthalpy ◽  
The Difference ◽  
Heat Capacity Measurements ◽  
Triple Point Temperature

In the present work we studied acridone and thioxanthone by combustion calorimetry of small amounts of substance, by sublimation calorimetry, by differential thermal analysis, and by heat capacity measurements. The thermodynamic quantities derived are as follows: For acridone: [Formula: see text] [Formula: see text] [Formula: see text] [Formula: see text] For thioxanthone: [Formula: see text] [Formula: see text] [Formula: see text] [Formula: see text] ΔfusHm = (35.50 ± 0.28) kJ mol−1, Ttp = (487.88 ± 0.02) K. The experimental results permitted us to determine for each molecule its resonance energy and to compare it with the theoretical value. This comparison fits well for acridone, which is planar. The difference observed in the case of thioxanthone shows that this molecule is not planar, in accord with literature structural results. From the experimental enthalpy of atomization of acridone, we determined an enthalpy value for the Cb—N bond. Using the enthalpy contributions previously determined in our laboratory, we found a value for the enthalpy of atomization of thioxanthone in accord with the experimental result. Keywords: thermodynamics; calorimetry; differential thermal analysis; acridone; thioxanthone; enthalpies of combustion, of sublimation, of fusion; resonance energy; enthalpies of atomization, of intramolecular bonds; triple point temperature.

Solid State Formation of Superconducting Phases in the T1-Ca-Ba-Cu-O System

1989 ◽  
Vol 169 ◽  
Author(s):  
T.W. Huang ◽  
M.P. Hung ◽  
T.S. Chin ◽  
H.C. Ku ◽  
S.C. Yang ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Solid State ◽  
Activation Energies ◽  
Kcal Mole ◽  
Preparation Methods ◽  
High Tc ◽  
Superconducting Phases ◽  
The One ◽  
Flowing Oxygen

AbstractDifferential thermal analysis (DTA) and thermal gravitometry analysis (TG A) under flowing oxygen show that the formation temperatures of the high Tc T12Ca2Ba2Cu3Ox (2223) and the low Tc T12CaBa2Cu2Ox (2212) phases lie at around 910 °C and 840 °C, respectively. The activation energies are as low as 50 kcal/mole for the 2223 phase and 35 kcal/mole for the 2122 phase. Thus the time for the formation of these phases can be within 30 minutes.Two preparation methods were tried, and the one with Ca3BaCu3O7 as a precursor was easier to attain pure high Tc 2223 phase than that prepared directly from component oxides and carbonates.

Article

1999 ◽  
Vol 77 (2) ◽  
pp. 249-257
Author(s):  
Raphaël Sabbah ◽  
Safi Ider
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Triple Point ◽  
Isonicotinic Acid ◽  
Picolinic Acid ◽  
Resonance Energy ◽  
Enthalpy Of Combustion ◽  
Pyridine Derivatives ◽  
Temperature Reference ◽  
Heat Capacity Measurements

The present work is concerned with a thermodynamic study of the three carboxypyridinic acids (general formula: C6H5NO2). It was achieved using four techniques: combustion calorimetry of small amounts of substance (a few milligrams), sublimation calorimetry, heat capacity measurements by the drop method, and differential thermal analysis. From this study, it was possible to determine the enthalpies of combustion, sublimation, formation, and fusion of these compounds and their triple point temperatures; to discuss the relative stability of the three molecules and to compare it to those of other pyridine derivatives; to determine the resonance energy and to compare it to those of other pyridine derivatives; to determine the atomization enthalpies of our compounds and an enthalpy value for the bonds of the group (C-N=C); to determine the nature and the enthalpy of the intermolecular bonds.Key words: thermodynamics, calorimetry, differential thermal analysis, carboxypyridinic acids, picolinic acid, nicotinic acid, isonicotinic acid, enthalpy of combustion, of sublimation, of fusion, of formation, of inter- and intramolecular bonds, resonance energy, triple point temperature, reference material.

Étude thermodynamique des trois isomères de l'acide chlorobenzoïque. Partie II

1995 ◽  
Vol 73 (9) ◽  
pp. 1538-1545 ◽  
Author(s):  
Raphaël Sabbah ◽  
Aaron Rojas Aguilar
Keyword(s):  
Nous Avons ◽  
Resonance Energy ◽  
Combustion Calorimetry ◽  
Enthalpies Of Formation ◽  
Condensed State ◽  
Thermodynamic Quantities ◽  
Chlorobenzoic Acid ◽  
Gaseous State ◽  
Calorimetric System ◽  
Experimental Values

Our isoperibol rocking-bomb calorimeter, previously described, has been modified to: (i) reduce and stabilize the heat exchange between the calorimetric system and its surroundings; (ii) change its thermometer; (iii) associate with it a computer program for the robotics of different steps of an experiment, data acquisition, and determination of the thermodynamic quantities. After testing these modifications and calibrating the calorimetric system, the enthalpies of formation in the condensed state and at 298.15 K of the three isomers of chlorobenzoic acid have been determined by combustion calorimetry. Associating these values with those of their enthalpies of sublimation previously measured, we determined their enthalpies of formation in the gaseous state. The experimental values of the thermodynamic functions [Formula: see text] [Formula: see text] are given for 2-chlorobenzoic acid, 3-chlorobenzoic acid, and 4-chlorobenzoic acid. From the experimental value of the enthalpy of atomization, it has been possible to determine an enthalpy value for the Cb—Cl bond. The experimental and theoretical values of the resonance energy of the three isomers are compatible. The relative stability of some monosubstituted derivatives of benzoic acid studied in our laboratory is also discussed. Keywords: thermodynamics, combustion calorimetry, differential thermal analysis; 2-chlorobenzoic acid, 3-chlorobenzoic acid, 4-chlorobenzoic acid, enthalpies of combustion, of formation, resonance energy, enthalpies of atomization, of intramolecular bonds, reference material.Notre calorimètre isopéribolique à bombe rotative, précédemment décrit, a été modifié: (i) en diminuant et en stabilisant les échanges thermiques entre le système calorimétrique et le milieu extérieur; (ii) en modifiant son thermomètre de mesure; (iii) en lui associant un système informatisé de robotique, d'acquisition et de traitement des signaux thermiques. Après avoir vérifié la bonne marche de l'appareil ainsi modifié et réalisé l'étalonnage du système calorimétrique, nous avons déterminé à 298,15 K et par calorimétrie de combustion les enthalpies de formation à l'état condensé des trois isomères de l'acide chlorobenzoïque. En associant ces valeurs à celles de leurs enthalpies de sublimation à 298,15 K, nous avons pu déterminer leurs enthalpies de formation à l'état gazeux. Les valeurs expérimentales des fonctions thermodynamiques [Formula: see text] [Formula: see text] sont données pour les acides 2-chloro-benzoïque, 3-chlorobenzoïque et 4-chlorobenzoïque. À partir de l'enthalpie d'atomisation expérimentale de ces trois acides, une valeur enthalpique a été proposée pour la liaison Cb—Cl dans ce type de composés. Les valeurs expérimentale et théorique de l'énergie de conjugaison sont compatibles. Une discussion sur la stabilité relative de quelques dérivés monosubstitués de l'acide benzoïque étudiés au laboratoire est aussi développée. Motsclés: thermodynamique, calorimétrie de combustion, analyse thermique différentielle; acide 2-chlorobenzoïque, acide 3-chlorobenzoïque, acide 4-chlorobenzoïque, enthalpies de combustion, de formation, énergie de conjugaison, enthalpies d'atomisation, de liaisons intramoléculaires, substance d'intercomparaison.

Energetics of intra- and intermolecular bonds in ω-alkanediols. III. Thermochemical study of 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol at 298.15 K

1990 ◽  
Vol 68 (5) ◽  
pp. 731-734 ◽  
Author(s):  
P. Knauth ◽  
R. Sabbah
Keyword(s):  
Thermal Analysis ◽  
Hydrogen Bond ◽  
Differential Thermal Analysis ◽  
Triple Point ◽  
Gaseous Phase ◽  
Enthalpies Of Formation ◽  
Thermochemical Study

The enthalpies of combustion and sublimation or vaporization of the title compounds were determined on milligram samples and used to derive, at 298.15 K, the enthalpies of formation in the gaseous phase and the enthalpies of atomization. The previous conclusions drawn from the investigation of the lower ω-alkanediols were confirmed: the enthalpy of a hydrogen bond in solid ω-alkanediols amounts to 27 kJ mol−1 and the intramolecular C—C and C—OH bond enthalpies to 343.2 and 819.5 kJ mol−1, respectively. The enthalpies of fusion and the triple point temperatures of the ω-alkanediols [Formula: see text] are reported and discussed. Keywords: ω-alkanediols, enthalpies of formation, triple point temperatures, differential thermal analysis, calorimetry.

Étude thermodynamique des trois isomères du dihydroxybenzène

1991 ◽  
Vol 69 (3) ◽  
pp. 481-488 ◽  
Author(s):  
R. Sabbah ◽  
E. N. L. E. Buluku
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Triple Point ◽  
Van Der Waals Interactions ◽  
Enthalpies Of Formation ◽  
Chemical Calculation ◽  
Conjugation Energy ◽  
Heat Capacity Measurements ◽  
Intramolecular Hydrogen ◽  
Enthalpies Of Sublimation

The present work is concerned with a thermodynamic study of the three isomers of dihydroxybenzene. By combustion calorimetry of small amounts of substance, sublimation calorimetry, differential thermal analysis, and heat capacity measurements, it was possible to determine the enthalpies of formation of 1,2-, 1,3-, and 1,4-dihydroxybenzene in the condensed and gaseous phases, their enthalpies of fusion and transition, and the temperature of their triple point and transition. The experimental results are used to discuss the relative stability and determine the conjugation energy of the three compounds. The values are in good agreement with the theoretical values obtained from a quantum chemical calculation. The enthalpies of atomization enabled us to determine an energy value for the intramolecular Cb—OH bond in dihydroxybenzenes and to correlate it with previous results obtained from a study of alkane-diols. The enthalpies of sublimation were discussed. An intramolecular hydrogen bond was displayed in the ortho isomer. Intermolecular hydrogen bonds associated with van der Waals interactions exist in dihydroxybenzenes. Their energy contributions were determined. Key words: thermodynamics, calorimetry, differential thermal analysis, 1,2-benzenediol or 1,2-dihydroxybenzene or catechol; 1,3-benzenediol or 1,3-dihydroxybenzeneorresorcinol; 1,4-benzenediol or 1,4-dihydroxybenzene or hydroquinone or quinol; enthalpies of combustion, of sublimation, of fusion, of transition, energy of conjugation, enthalpies of atomization, of inter- and intramolecular bonds; triple point and transition temperatures.

The germanium–selenium phase diagram

1969 ◽  
Vol 47 (14) ◽  
pp. 2555-2559 ◽  
Author(s):  
L. Ross ◽  
M. Bourgon
Keyword(s):  
Thermal Analysis ◽  
Phase Diagram ◽  
Differential Thermal Analysis ◽  
Composition Range ◽  
The One ◽  
Good Agreement

The Ge–Se phase diagram was determined in the composition range 0–66.67 at. % Se by the method of differential thermal analysis. The diagram differs totally from the one reported by Liu etal. (1) but is in good agreement with the diagram recently reported by Karbanov etal. (13). In its broad features the Ge–Se phase diagram is quite similar to the diagrams of the Ge–S, Sn–S, and Sn–Se systems.

Zeolites Fit For A Crown: Probing Host-Guest Interactions with Thermogravimetric Methods

2018 ◽  
Author(s):  
Asel Sartbaeva ◽  
Paul R. Raithby ◽  
Remi Castaing ◽  
Antony Nearchou
Keyword(s):  
Mass Spectrometry ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Petrochemical Industry ◽  
Rational Use ◽  
New Methodologies ◽  
First Time ◽  
Kinetics Of

Through a combination of thermogravimetry, mass spectrometry and differential thermal analysis, we demonstrate for the first time that all four zeolites show experimental differences in their host-guest interactions with 18C6. In addition, we have estimated the kinetics of 18C6 decomposition, which is a technique that has not been applied to zeolites previously. Using these findings as a toolkit, a more rational use of OSDAs can be utilised to prepare designer zeolites. Furthermore, the new methodologies presented herein can be applied to current zeolites, such as MFI-type zeolites used in the petrochemical industry.

PHASE EQUILIBRIUM IN THE AS2TE3-TM2TE3 SYSTEM.

2020 ◽  
Vol 5 (8(77)) ◽  
pp. 65-68
Author(s):  
Teymur Mammad Ilyasly ◽  
Rahman Hasanaga Fatullazade ◽  
Zakir Islam Ismailov ◽  
Nigar Nadir Jafarova
Keyword(s):  
Thermal Analysis ◽  
Solid Solution ◽  
Differential Thermal Analysis ◽  
Phase Equilibrium ◽  
Physicochemical Properties ◽  
Thermal Effects ◽  
Isothermal Annealing ◽  
Intermediate Phase ◽  
Physicochemical Analysis ◽  
Two Phases

The synthesis of alloys of the system was carried out stepwise in rotary furnaces. The synthesis mode was selected based on the physicochemical properties of the elementary components. For homogenization, the alloys were subjected to isothermal annealing at 750 and 1275 K, depending on the Tm2Te3 concentration, for 250 h after homogenization of the alloys, they were subjected to physicochemical analysis. The results of differential thermal analysis showed that reversible thermal effects are observed in the alloys of the system. In alloys in a 1: 1 ratio, a new intermediate phase is formed with a composition corresponding to the TmAsTe3 compound. The homogeneity area is observed in the concentration range 52.5-47.5. It was found that in the concentration range 98.5-52.5 Tm2Te3 there are two phases - a mixture of β and of the solid solution, and in the concentration range of 47.51 mol% Tm2Te3 phases and α are in equilibrium. ) 66 The eutectic has coordinates of 11.5 mol Tm2Te3 at a temperature of 575 K.

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