MEASUREMENTS AND CORRELATION OF OSMOTIC COEFFICIENTS AND EVALUATION OF VAPOR PRESSURE FOR SOLUTIONS OF KCH3COO AND NaCH3COO IN METHANOL AT 25 °C†
Karamat Nasirzadeh,a,b* Roland Neuederb
a Department of Chemistry, Faculty of
b Institute of Physical and Theoretical Chemistry,
Fax: +49-941-9434532; E-mail: Karamat.firstname.lastname@example.org
†This paper is dedicated to Prof. Josef Barthel in honour of his 75th birthday.
The osmotic coefficients of potassium acetate and sodium acetate in methanol have been measured by the isopiestic method at 25 °C. Sodium iodide was used as isopiestic standard for the calculation of osmotic coefficients. The molality ranges covered in this study correspond to about 0.17-2.51 mol×kg-1 for potassium acetate and 0.25-1.76 mol×kg-1 for sodium acetate. The system of equations of Pitzer–Mayorga and MSA-NRTL were used to fit osmotic coefficients. The parameters from the fit were used to calculate the vapor pressures. The osmotic coefficient data are successfully correlated with these models, which provide reliable predictions of vapor pressures.
Key words: osmotic coefficient, isopiestic, methanol, models