The data correlations from Multiflash and DIPPR were used fo
The data correlations from Multiflash™  and DIPPR  were used for the liquid volume and heat of vaporization. For vapour pressure the curves were regressed from the experimental data present on both the DIPPR  and TRC  databases. As for liquid heat capacities both the latter databases were used but also some other literature data was taken into account , , . For the vapour density data, the data from the TRC database , Polikhronidi et al.  and Bazaev et al.  were considered, elsewhere estimates where generated from the ideal gas law.
Results and discussion
Conclusions Other relevant issue is the alpha function used. Due to the high number of parameters, the optimization of the vapour pressure had to be extended to larger ranges of temperature so that relevant derivative properties presented a correct behaviour. To address this issue it is intended to follow the work of Jaubert and co-workers  in future developments of the CPA parameterization.
Funding and acknowledgments
Introduction Water has frequently been used for enhancing oil production in reservoirs with severe conditions. Owing to the importance of the phase behavior of water + hydrocarbon mixtures at high temperatures and pressures in the petroleum industry and other fossil-fuel processes, it has received wide attention , , , . Evaluating the mutual solubility of water and hydrocarbons at elevated temperature and pressure is a challenging task in designing, developing and optimizing hydrocarbon recovery processes and petrochemical plants. In various thermal recovery processes of heavy vps34 and bitumens, e.g., Steam Assisted Gravity Drainage (SAGD) and Cyclic Steam Stimulation (CSS), hydrocarbons are produced by heating reservoir formations with a hot heat-carrying fluid such as water. Increasing temperature reduces the oil phase viscosity, as the consequence of hot water injection, in a manner that oil can freely move . Increasing oil mobility leads to thermal recovery improvement. Accurate estimation of the amount of water dissolved in heavy oils has a remarkable effect on thermal recovery simulation . It has been widely approved that temperature increase has a significant impact on water solubility in hydrocarbons , . At temperatures above 150OC, water solubility in oil phase increases dramatically  which may reach up to 40 mol% in the oil phase . Comparing the experimental data reveals that at any thermodynamic condition, water solubility in hydrocarbon-rich phase is several orders of magnitude greater than oil solubility in water phase , , . From practical point of view, in petroleum production industry, water solubility in hydrocarbon phase is more important than the latter. Several researchers , ,  measured mutual solubility for various pure hydrocarbons and water mixtures at high temperatures and correlated the solubility data using empirical correlations. Maczynski et al. , , , ,  and Shaw et al. , , , , , ,  published a comprehensive literature review on experimental mutual solubility data of water and pure hydrocarbon mixtures. Griswold and Kasch  measured water solubility in different petroleum fractions. Also, Glandt and Chapman  represented water solubility data in several heavy oils and bitumen; and Amani et al. ,  measured water solubility in Athabasca bitumen and mixtures of Athabasca bitumen and toluene. Beside experimental techniques, several mathematical approaches have been suggested to describe the mutual solubility of water + hydrocarbon mixtures, but just very few models have the potential to calculate the compositions of both phases simultaneously over wide thermodynamic conditions. Some models predict the hydrocarbon solubility in water , , while the others generally focus on water solubility in hydrocarbons , , . The empirical correlations which estimate water solubility in hydrocarbon systems also can be found in API Technical Data  or other references , . Amani et al.  developed empirical equations for water solubility in ill-defined and asymmetric hydrocarbon mixtures at temperatures below the critical point of water. They did a broad literature review on water solubility in hydrocarbons at elevated temperatures , , . These correlated models are limited to specific properties and are generally empirical-based. These correlations cannot be extended to evaluate other important properties of mixtures. From this viewpoint, equations of state are more preferred to describe the properties of fluids and their mixtures under various thermodynamic conditions.