Application of the Cell Method to the Statistical Thermodynamics of Solutions. II. Experimental

Abstract

In connection with the theory of solutions proposed by Prigogine and Mathot [J. Chem. Phys. 20, 49 (1952)], total vapor pressures and volume changes on mixing have been measured for the systems: $${\mathrm{CCl}}_4–\mathrm{C}(\mathrm{Me}{)}_4\mathrm{\hspace{0.17em}\hspace{0.17em}}\mathrm{I}$$ $${\mathrm{C}}_6{\mathrm{H}}_{12}–\mathrm{C}(\mathrm{Me}{)}_4\mathrm{\hspace{0.17em}\hspace{0.17em}}\mathrm{II}$$ $${\mathrm{C}}_6{\mathrm{H}}_6–\mathrm{C}(\mathrm{Me}{)}_4\mathrm{\hspace{0.17em}\hspace{0.17em}}\mathrm{III}.$$ Volume changes only for the systems: $$\mathrm{CCl}(\mathrm{Me}{)}_3–{\mathrm{CCl}}_4\mathrm{\hspace{0.17em}\hspace{0.17em}}\mathrm{IV}$$ $${\mathrm{CCl}}_2(\mathrm{Me}{)}_2–{\mathrm{CCl}}_4\mathrm{\hspace{0.17em}\hspace{0.17em}}\mathrm{V}$$ $${\mathrm{CCl}}_3(\mathrm{Me}\mathrm{)–}{\mathrm{CCl}}_4\mathrm{\hspace{0.17em}\hspace{0.17em}}\mathrm{VI}$$ $$\mathrm{C}(\mathrm{Me}{)}_3\mathrm{OH}–{\mathrm{CCl}}_4\mathrm{\hspace{0.17em}\hspace{0.17em}}\mathrm{VII}.$$ For the first three systems I, II, and III, one observes a positive excess free energy (positive deviations to the Raoult law) together with a negative excess volume (contraction on mixing), whereas for the last four IV, V, VI, and VII there is a gradual passage from negative (IV) to positive (VII) excess volume. These results are discussed in terms of the molecular interactions AA, BB, and AB. Reasonable agreement is observed between Prigogine and Mathot's theory and experiment.