Vapor-liquid and liquid-liquid equilibria in the water + poly(propylene glycol) system

•New data on phase equilibria in poly(propylene glycol) [Mn = 425] + water system.•VLE were measured at four isotherms 323.15, 333.15, 343.15, and 353.15 K.•LLE solubility was determined at 320–350 K; LCST was found at 320.2 K.•Correlation of equilibrium data with UNIQUAC type models accounting for FV effects.•Models enable prediction of phase equilibria even at extrapolated conditions.