1-Aminopropyl-3-methy-limidazolium bromide([APMIm][Br])is a functional ionic liquid(IL)for good absorption to carbon dioxide and its aqueous solution can be employed to the process of high efficiency absorption and desorption cycle.It is important to study the property of its aqueous solutions.In this study

reliable experimental data on the vapor-liquid equilibrium of[APMIm][Br]aqueous solution were obtained under the condition of middle-low temperatures.The vapor pressures of the binary system was measured at 278.15-384.15 K and in a range of 10.0%-90.9% ionic liquid(g·g-1).An activity coefficient model with an idle factor for association of IL moles was applied by taking into account the aggregation effects of IL molecules in aqueous solutions.The model can effectively present the vapor-liquid equilibrium characteristics of IL solution for middle-low temperatures and full range of mole concentration and correlate the experimental data very well with a relative mean deviation of 2.15%.