Solubilities of carbon dioxide in n-octadecane and its binary mixtures with n-decane have been reported at 372.8K over the pressure range 1-6 MPa. The binary mixtures of n-octadecane and n-decane were prepared at 0.25, 0.5, and 0.75 mole fractions of n-decane. The density and viscosity of n-octadecane and its binary mixtures were first measured. Then, the phase behaviour measurements were undertaken with a designed PVT apparatus to investigate the solubility, gas-expanded liquid density and viscosity when the liquid hydrocarbon was saturated with carbon dioxide. The solubility data showed that the solubility of carbon dioxide in n-decane, n-octadecane, and their binary mixtures rose with pressure and reduced as the mixture became heavier. The data indicated the dissolution of carbon dioxide in pure species or their binary mixtures caused a decline in the viscosity of saturated liquid phase and led to an increase in density of gas-expanded liquid. The solubility and density measurements were then correlated with Soave-Redlich-Kwong and Peng-Robinson equations of state. The volume translation technique and the adjustment of binary iteration parameters were applied to fit the generated data. The modelling results indicated that the volume translation technique should be applied to all components present in the mixture for the densities to be accurately predicted. (C) 2012 Elsevier B.V. All rights reserved.