Static Dielectric Constants of Acetonitrile/Water Mixtures at Different Temperatures and Debye-Hückel A and a0B parameters for Activity Coefficients

LEONARDO G. GAGLIARDI; CECILIA B. CASTELLS; CLARA RÀFOLS; MARTÍ ROSÉS; ELISABETH BOSCH

JOURNAL OF CHEMICAL AND ENGINEERING DATA

ACS

Lugar: Washington; Año: 2007 p. 1103 - 1107

0021-9568

<!-- @page { size: 21.59cm 27.94cm; margin: 2cm } P { margin-bottom: 0.21cm } --> Static dielectric constants of acetonitrile/water mixtures in the whole composition range and within the temperature range from 15ºC to 60ºC have been measured. The values were fitted to a unique equation as a simultaneous function of temperature and acetonitrile composition. Densities of these mixtures at temperatures from 5 to 55ºC and different compositions have been collected from the literature. The complete data set was critically analyzed and after excluding outliers the values were also fitted to a unique equation as a function of temperature and acetonitrile composition. From the dielectric constants and densities the activity coefficients of ions can be calculated by means of the Debye-Hückel approach, allowing the study of the ionic equilibria, determination of reference pH values or acidity constants in any acetonitrile/water mixture at any temperature within this range.