Liquid-Vapour Equilibria. X. The Systems Acetone+Nitromethane and Acetone+Acetonitrile at 45°C

Abstract

Liquid-vapour equilibrium data are given for the systems acetone+nitromethane and acetone+acetonitrile at 45.00 °C. The data are used to calculate the excess free energy of mixing for these systems. The former system has a negative value of the excess free energy of mixing and shows a change in sign of the deviation of the activity of nitromethane from the Raoults law value at a mole fraction of acetone of 0.36. A value of the virial coefficient β₁₂ in the equation of state of the mixed vapours was estimated from the equilibrium data for this system. The excess free energy of mixing for the system acetone+acetonitrile is zero within the experimental error over the whole concentration range. The Stockmayer potential was used to calculate values of β₁₂, for the binary systems formed from acetone, nitromethane, and acetonitrile. For the system acetone+nitromethane the value estimated from our data is more negative than the value calculated using the Stockmayer potential, indicating a specific interaction, possibly hydrogen bonding, between the acetone and nitromethane molecules.