A dynamic recirculation apparatus has been used to determine the isobaric phase equilibria of binary 1-propoxy-2-propanol mixtures with water and different alcohols (methanol, ethanol, 2-butanol and 1 hexanol). The systems exhibit both positive and negative deviations from Raoult's law. No azeotropic mixture is found in any of the systems under investigation. The binary diagram of water/1-propoxy-2-propanol (PnP) shows the well-known liquid-liquid-separation. The experimental results are correlated with the Wilson, NRTL and UNIQUAC model and also compared to the COSMO-RS predictive model and the modified UNIFAC group-contribution method. Additionally, the vapour pressure of PnP has been determined experimentally up to 140 degrees C as prerequisite for modelling of the data. (c) 2008 Elsevier B.V. All rights reserved.