Isobaric vapor-liquid equilibrium data for the isopropanolwater-1-octyl-3-methylimidazolium tetrafluoroborate system

Isobaric vapor-liquid equilibrium(VLE) data for the isopropanol-water system containing the ionic liquid(IL) 1-octyl-3-methylimidazolium tetrafluoroborate(BF4) have been measured at 101.32 kPa in a modified Othmer still. The vapor-liquid equilibrium curve for the isopropanol-water system with added IL deviates from the line when the mole fraction of BF4 reaches 10%. When the mole fraction of BF4 reaches 20% or 30%,the deviation from the line increases further.The IL shows a salt effect,which increases the volatility of isopropanol relative to that of water,and even leads to the disappearance of the azeotropic point.As a result,it is concluded that BF4 can be employed as an entrainer for the extractive distillation of the isopropanol-water system.Based on the VLE data,the optimum mole fraction of BF4 is about 20%.The measured ternary data were correlated using the NRTL model,and the correlated result was found to be similar to the experiment data.