Thermodynamics Research Center / ThermoML | Fluid Phase Equilibria

ABSTRACT

Limiting activity coefficients were measured for 1-chlorobutane in water and in aqueous solutions of the additives 1-methylimidazole (MeIm), ionic liquid 1-butyl-3-methylimidazolium chloride (BMImCl), and sodium chloride (NaCl) at temperatures from (273.35 to 308.15)K and additive concentrations from (0 to 0.6)mol kg-1 employing the methods of inert gas stripping and exponential saturator. The data measured in this work enabled us to establish recommended temperature dependence for limiting activity coefficients of 1-chlorobutane in water. To this end, the present data were supplemented with (i) compiled and critically evaluated limiting activity coefficient data from the literature and (ii) an estimated value of infinite dilution partial molar heat capacity and subsequently fitted to a suitable model equation. The recommended values of limiting activity coefficients and from them inferred values of solubility, Henry fs law constant, and air-water partition coefficients are reported at several temperatures. The effect of the additives corresponds to either salting-in (MeIm, BMImCl) or salting-out (NaCl). The temperature and additive concentration dependence of limiting activity coefficients were fitted simultaneously using a five-parameter model equation. The enthalpy and entropy of the transfer of 1-chlorobutane from water to aqueous solutions of the additives were further derived, disclosing the thermodynamic origin of the observed salting-in/salting-out processes.