Vapor-liquid and critical behavior of binary systems of hydrogen chloride and n-alkanes: Experimental data and soft-SAFT modeling

The purpose of this work is to check the capability of the crossover soft-SAFT equation of state to predict the phase behavior of hydrogen chloride/n-alkane mixtures based on experimental data. The hydrogen chloride parameters were optimized using the experimental information, while the parameters for the n-alkanes were obtained from published correlations to the molecular weight of the compounds. We have found that a unique binary parameter with a constant value for the whole family provides an excellent description of the behavior of hydrogen chloride + propane and hydrogen chloride + dodecane mixtures in a broad range of temperatures and pressures, as well as the critical line of the mixture. The model confirms that HCl + propane exhibits type-I critical behavior, while HCl + dodecane shows a type-II critical behavior. Taking advantage of the transferability of the parameters, the critical transition from type-II to type-III has been investigated with the equation in a predictive manner. Although results are very sensitive to the binary parameter value, there are indications to assert that type-III is achieved close to the HCl + heneicosane binary system.