Conductance of dilute sodium acetate solutions to 469 K and of acetic acid and sodium acetate/acetic acid mixtures to 548 K and 20 MPa

摘要

In order to obtain accurate association constants for sodium acetate,a very precise flow method was sued to measure the electrical conductivity of dilute aqueous solutions of sodium acetate at ambient conditions and 469 K and 20 MPa.Measurements at ambient conditions,469 and 548K and 20 MPa,were also made on sodium acetate/acetic acid mixtures and acetic acid.In order to determine the limiting the equivalent conductances and the association constant for sodium acetate,and dissociation constant for acetic acid,the results were fitted to two modern conductance equations (Fuoss-Hsia-Fernandez-Prini and Turq-Blum-Bernard-kunz) with accompanying activity coefficient models (mean spherical appproximation and the Debye-Huckel with the Bjerrum distance).The choice of conductance equation,activity coefficient model,assumed values for the limiting equivalent conductance for the limiting equivalent conductance for minor species,and assumed equilibrium constants for minor reactions,did not significantly change the results are the most accurate sodium acetate ion-pairing constants published to date.Our results for acetic acid are in good agreement with previously published results from other laboratories.