Isothermal vapour-liquid equilibrium data were measured for binary mixtures of carbon dioxide with either hexafluoropropylene or hexafluoropropylene oxide at five temperatures in the (233-273) K range. The experimental data presented in this manuscript supplement data which were previously measured at temperatures of 273 K and above. The data is required for the assessment of the operating conditions for a purification process for the production of high purity hexafluoropropylene oxide from a mixture of hexafluoropropylene and hexafluoropropylene oxide. The experimental P-x-y data were measured using an apparatus based on the "static-analytic" method. The experimental data were satisfactorily correlated using the Peng-Robinson Equation of State with the Mathias-Copeman alpha function. (C) 2016 Elsevier B.V. All rights reserved.