Simultaneous determination of equilibrium constants and enthalpy changes by titration calorimetry: Methods, instruments, and uncertainties.

The development of a continuous isothermal titration calorimetric method for equilibrium studies.

In this work we report the thermodynamic parameters for the protonation of a homologous series of linear dicarboxylates having the molecular formula, HOOC-(CH 2 ) n -COOH, with n = 0 - 7 (n = 0 oxalate; n = 1 malonate; n = 2 succinate; n = 3 glutarate; n = 4 adipate; n = 5 pimelate; n = 6 suberate; n = 7 azelate). The investigation was performed by potentiometry (H + -glass-electrode) at 25°C in different ionic media and different ionic strengths (NaCI: 0 ≤ / [mol-L -1 l ≤ 4.9; Et 4 NI: 0 ≤ I (mol-L -1 ] ≤ 1). General equations for the dependence on ionic strength of the thermodynamic parameters were used, and the relative parameters are reported. The influence of the length of the alkyl chain on protonation constants and on their dependence on ionic strength is discussed. Some recommended values of protonation constants are reported by considering present results and literature ones.

Medium and Alkyl Chain Effects on the Protonation of Dicarboxylates in NaCl(aq) and Et4NI(aq) at 25°C

Apparent molar enthalpies have been determined as a function of concentration by heat conduction calorimetry for aqueous solutions of the phenothiazine drugs chlorpromazine hydrochloride, promethazine hydrochloride, and promazine hydrochloride in the presence of added electrolyte (0.025−0.10 mol dm-3 NaCl). The concentration dependence of the apparent molar enthalpy could be quantitatively described using a mass action model of association based on the Guggenheim equations for the activity coefficients for mixed electrolytes. Derived values of the monomer−counterion interaction coefficient became increasingly negative with increase of salt concentration, suggesting that electrolyte addition promoted association at concentrations below the critical micelle concentration (cmc). Calculations of the fraction of each drug in the form of micelles as a function of concentration further confirmed the tendency for premicellar association. Significant differences in properties were observed between promethazine and...

A calorimetric study of the influence of electrolyte on the micellisation of phenothiazine drugs in aqueous solution

Thermogenese: Application des filtrages electronique et numerique inverses en calorimetre a conduction

Développement du domaine d'application de la calorimétrie à conduction et de l'analyse calorimétrique différentielle en thermodynamique et en cinétique

M. Barres

Papers

Développement du domaine d'application de la calorimétrie à conduction et de l'analyse calorimétrique différentielle en thermodynamique et en cinétique

Filtrage electronique inverse en microcalorimetrie application a la correction automatique des signaux

Détermination des constantes thermodynamiques d'équilibres en solution par calorimétrie à conduction et flux de réactif: I. Description de la méthode