On the Physical Meaning of the Isothermal Titration Calorimetry Measurements in Calorimeters with Full Cells

We have performed a detailed study of the thermodynamics of the titration process in an isothermal titration calorimeter with full cells. We show that the relationship between the enthalpy and the heat measured is better described in terms of the equation Δ H = Winj + Q (where Winj is the work necessary to carry out the titration) than in terms of ΔH = Q. Moreover, we show that the heat of interaction between two components is related to the partial enthalpy of interaction at infinite dilution of the titrant component, as well as to its partial volume of interaction at infinite dilution

Thermodynamics and Thermokinetics to Model Phase Transitions of Polymers over Extended Temperature and Pressure Ranges Under Various Hydrostatic Fluids

We are grateful to InTech the publisher of the book "Thermodynamics - Interaction Studies - Solids, Liquids and Gases", for letting this publication being archived in this Open Access repository. The publication is available from Intech Open Access Publisher: http://www.intechopen.com/articles/show/title/thermodynamics-and-thermokinetics-to-model-phase-transitions-of-polymers-over-extended-temperature-aInternational audienceA scientific understanding of the behaviour of polymers under extreme conditions of temperature and pressure becomes inevitably of the utmost importance when the objective is to produce materials with well-defined final in-use properties and to prevent the damage of materials during on-duty conditions. The proper properties as well as the observed damages are related to the phase transitions together with intimate pattern organization of the materials. Thermodynamic and thermokinetic issues directly result from the thermodynamic independent variables as temperature, pressure and volume that can stay constant or be scanned as a function of time. Concomitantly, these variables can be coupled with a mechanical stress, the diffusion of a solvent, and/or a chemically reactive environment. A mechanical stress can be illustrated in a chemically inert environment by an elongation and/or a shear. Diffusion is typically described by the sorption of a solvent. A chemical environment is illustrated by the presence of a reactive environment as carbon dioxide or hydrogen for example. Challenging aspects are polymer pattern multi scale organizations, from the nanometric to the macrometric scale, and their importance regarding industrial and technological problems, as described in the state of the art in Part 2. New horizons and opportunities are at hands through pertinent approaches, including advanced ad hoc experimental techniques with improved modelling and simulation. Four striking illustrations, from the interactions between a solvent and a polymer to the growth patterns, are illustrated in Part 3

On the Physical Meaning of the Isothermal Titration Calorimetry Measurements in Calorimeters with Full Cells

We have performed a detailed study of the thermodynamics of the titration Process in an isothermal titration calorimeter with full cells. We show that the relationship between the enthalpy and the heat measured is better described in terms of the equation ΔH = Winj + Q (where Winj is the work necessary to carry out the titration) than in terms of ΔH = Q. Moreover, we show that the heat of interaction between two components is related to the partial enthalpy of interaction at infinite dilution of the titrant component, as well as to its partial volume of interaction at infinite dilution

Enthalpies de mélange des α, ω-dichloroalcanes avec des hydrocarbures

Les auteurs rapportent les enthalpies d’excès, hE, des mélanges binaires suivants : de l’heptane n avec le 1,3-dichloropropane, le 1,4-dichlorobutane, le 1,5-dichloropentane et le 1,6-dichlorohexane ; du benzène avec le 1,3-dichloropropane, le 1,4-dichlorobutane, le 1,5-dichloropentane et le 1,6-dichloro- hexane. Les données expérimentales sont interprétées en utilisant les équations dérivées du modèle réticulaire, en ternies d’interaction entre surfaces moléculaires, dans l’approximation quasi chimique. La comparaison des valeurs de hE ainsi calculées avec les valeurs expérimentales fait apparaître l’existence d’une interaction intramoléculaire chlore-chlore dans les α,ω-dichloroalcanes, croissante avec le rapprochement des atomes de chlore

Isothermal Titration Calorimetry: Application of the Gibbs-Duhem Equation to the Study of the Relationship Between Forward and Reverse Titrations

International audienceIn this work we rigorously demonstrate that, in dilute solutions, the partial enthalpy of interaction of the ligand can be measured by a forward titration and that the partial enthalpy of interaction of the macromolecule with the ligand can be calculated from the Gibbs–Duhem equation. Using a reverse titration, it is possible to experimentally obtain the partial enthalpy of interaction of the macromolecule and to calculate that of the ligand. Based on this fact, we propose a thermodynamic criterion to experimentally discern when the forward process is equal to or different from the reverse process: they are equal (or different) if the interaction partial enthalpies obtained experimentally are equal to (or different from) those calculated from the Gibbs–Duhem equation. The above criterion is applied to four systems taken from the literature. The first system features the interaction between a bilayer and a surfactant. The second system features a binding interaction with two binding sites that are equivalent and independent. The final two systems feature binding interactions with two non-equivalent binding sites

Enthalpies de mélange d’alcanoates d alcoyle et d’alcanones-2 en séries homologues avec un alcane linéaire

Les enthalpies de mélange de l’heptane-n avec les esters et les cétones suivants en séries homologues ont été déterminées, à 298,15 K, à l’aide d’un microcalorimètre Picker à écoulement : atétate de méthyle, propanoate de méthyle, butanoate de méthy- k, pentanoate de méthyle, hexanoate de méthyle, butanone-2, pentanone-2, hexanone-2 et heptanone-2. Les enthalpies d’excès à dilution infinie, [math] du composé carbonylé dans l’alcane, déduites de ces mesures, ainsi que les [math] des acétates d’alcoyle dans l’hexane-n, déduites d’un travail antérieur, semblent compatibles avec l’existence d’une structure quasi-cyclique intramoléculaire dans le cas de l’acétate de propyle

Enthalpies de mélange des chlorures organiques avec des hydrocarbures

Les auteurs rapportent les enthalpies de mélange des systèmes binaires suivants : 1-chlorobutane avec l’heptane n, le décane n, l’hexadécane n, le benzène, le toluène, l'éthyl-benzène, le propylbenzène et le butylbenzène ; chloroben- zène, chloromélhylbenzène et (2-chloroéthyl)benzène. avec l’heptane n. Les données expérimentales sont interprétées en utilisant des équations dérivées essentiellement du modèle réticulaire, mais en termes d’interaction entre surfaces moléculaires dans l’approximation quasi chimique.Les enthalpies d’excès expérimentales de presque tous les systèmes étudiés ont pu être reproduites à l’aide de deux paramètres caractérisant les surfaces de contact du benzène ft du chlore, et de 3 paramètres représentant les enthalpies d’interéchange des paires de surface de contact : aliphatique/aromatique, aliphatique /chlore, aromatique /chlore.On constate l’effet inductif du groupement alkyl sur les interactions entre les hydrocarbures aromatiques substitués et les chlorures aliphatiques, ainsi que la forte interaction filtre l’atome de chlore et le noyau benzénique du chloro- benzène

Thermodynamics of organic mixtures. A generalized quasichemical theory in terms of group surface interactions

A general quasi chemical theory in terms of group surface interactions is presented. The theory is applied to several basic classes of organic mixtures comprising n-alkanes, aromatic hydrocarbons, cyclohexane, tetrachloromethane, ethers and chloroalkanes. Interchange Gibbs energies and enthalpies are tabulated for ten contact pairs. Comparison with experimental Gibbs energies and enthalpies shows quite satisfactory agreement for all of the systems investigated. Possible sources of discrepancy and ways of refining the model are discussed