The behaviour of the partially miscible liquid-liquid system methyl ethyl ketone/water at elevated pressures.

Equilibrium compositions of conjugate liquid phases in the system methylethyl ketone (MEK) - water (H[2]O) have been measured over a range of temperatures from 25°C to 100°C and at pressures up to 17,500 psi extending considerably the range of conditions previously investigated. This method of investigation, which relies on the analysis of equilibrium phases, gives results which are not entirely consistent with the previous methods used. These earlier methods involve the location of the boundary of the two phase envelope in the pressure-temperature-composition (P-T-x) space by detec- ting some discontinuity in (aZ/aP)T,x or (aZ/AT)P,x where Z is the measured property. The densities of a range of methyl ethyl ketone water mixtures which are homogeneous at atmospheric pressure have been determined and their compressibilities measured at three temperatures and pressures up to 30,000 psi. The applicability of a number of simple solutions of the Gibbs-Duhem equation to the observed behaviour of this binary system has been examined but none was found to describe the system's equilibrium and volummetric behaviour adequately