Vapour-liquid, liquid-liquid and liquid-liquid-vapour equilibria in the binary system consisting of trifluoromethane (refrigerant R23) and 1-phenyloctane were determined in the temperature range T=250-400 K and at pressures up to 15 MPa The experiments were carried using a Cailletet apparatus according to the synthetic method The investigated system exhibits type III phase behaviour according to the classification of van Konynenburg and Scott. Modelling of the equilibrium data was done with the Peng-Robinson (PR) and Soave-Redlich-Kwong (SRK) equations of state coupled with classical van der Waals mixing rules In order to predict the global phase behaviour of the system, one single set of binary parameters was used The topology of the phase behaviour was correctly reproduced (C) 2010 Elsevier B V All rights reserved