The influence of a large molecular alcohol on thermodynamic phase behaviour is investigated for its potential use in CCS: New isothermal (vapour + liquid) equilibria and (vapour + liquid + liquid) equilibria data for the (carbon dioxide + 1-undecanol) system are reported at several temperatures (303.15, 313.15, 323.15, and 333.15) K and pressures up to 15 MPa, together with the pressure-temperature data of the three phases (liquid + liquid + vapour) equilibrium curve up to the upper critical endpoint. A static-analytical method with phases sampling was used. The experimental results of this study are compared with literature data when available, and discussed. The new data and all available literature data for the (carbon dioxide + 1-undecanol) binary system are modelled with three cubic equations of state, namely the General Equation of State, Peng-Rcibinson, and Soave-Redlich-Kwong with classical van der Waals mixing rules. The aforementioned EoS were used to model the phase behaviour of the (carbon dioxide + 1-undecanol) binary system (critical curves, the three phases equilibrium curve, isothermal VLE, and (vapour + liquid + liquid) equilibria, using a semi-predictive approach. The calculations results are compared to the new data reported in this work and to all available literature data. The results show a satisfactory agreement between the models and the experimental values. (C) 2015 Elsevier Ltd. All rights reserved.