A new equilibrium cell with variable cell volume for static vapour-pressure measurements

In this work, we present a new equilibrium cell with variable cell volume for static vapour-pressure measurements. This new cell allows a reduction in the time required to reach vapour-liquid equilibria of systems showing strong deviations from ideality. For the system 2-butanone + water, the time to reach equilibrium is reduced from more than 8 h down to 1.5 h. To achieve this, the components are mixed in the liquid phase before the formation of a vapour phase is allowed. A piston moving into the cell is used to condense the vapour. After mixing the liquid components, the piston is retracted and the equilibrium vapour allowed to form. Isothermal total-pressure data for the systems 2-butanone + water and cyclohexane + toluene determined with this new cell are presented.