Liquid–liquid equilibrium for the quaternary system water + tetrahydrofuran + n-heptane + butyl acetate mixture at 25 °C and atmospheric pressure

Liquid–liquid equilibrium for the quaternary system water + tetrahydrofuran + n-heptane + butyl acetate mixture was measured at 25 °C and atmospheric pressure. Binodal curves, tie-lines, distribution, and selectivity for the quaternary system have been determined in order to investigate the effect of using binary solvents, n-heptane and butyl acetate, on extracting tetrahydrofuran from aqueous solution. In addition, these experimental tie-line data were also compared with the values predicted by the UNIFAC model. It is found that the UNIFAC group interaction parameters used for LLE could not provide a good prediction.