Study On Phase Behavior Of Ionic Liquid / Acetone / CO <2> / Ternary System And Its Application

With the awareness of environment protection strengthened, the green solvents-ionic liquids and the green technology-supercritical fluids extraction were paid more and more attention. Ionic liquids could be used in homogeneous reaction because of its great solubility to most organic and inorganic compounds, but its low volatility has the disadvantage of the separation of product. Carbon dioxide (CO2) can be a separation switch for ionic liquid and organic mixtures. Based on this phenomenon, it is possible to combine reaction and separation in one system of ionic liquids, organic solvents and CO2. The phase behavior research of CO2/organic solvents/ionic liquids ternary system is the foundation of its application research.The high-pressure phase behavior of the ternary system containing acetone,1-octyl-3-methylimidazolium chloride ([Omim]Cl) and CO2was studied experimentally at temperatures of313.15K,353.15K and393.15K with the pressure at5.8MPa,7.8MPa,9.8MPa,12.1MPa and14.9MPa. It was found that at constant temperature, the mole fraction of CO2increased with the increase of pressure in both top and bottom phases and the mole fraction of acetone in the bottom phase decreased. At constant pressure, the mole fraction of acetone increased with the increase of pressure and the mole fraction decreased in both top and bottom phases. Based on the experiment data, the ternary phase diagrams were drawn. Two phase regions took place in every diagram and the areas of two phase regions decreased with the increase of pressure and increased with the increase of temperature. Simultaneously, the distribution coefficients of the components were calculated on the basis of phase equilibrium data. At14.9MPa, the distribution coefficients of CO2are approximately equal to one at the temperatures of313.15K,353.15K and393.15K and increased with the increment of temperature.The solubility of5-hydroxymethylfurfural in this CO2/acetone/[Omim]Cl ternary system was studied based on the experiment results above. At the same time, illustrated by the case of5-hydroxymethylfurfural production from fructose, the hypothesis of a simultaneous reaction and separation system was proposed and the optimized reaction condition was studied. Compared with the traditional production of 5-hydroxymethylfurfural, the production of5-hydroxymethylfurfural in this ternary system could largely improve the yield of5-hydroxymethylfurfural. It turns out that the yield of5-hydroxymethylfurfural would be highest at393.15K and8MPa with the reaction time of4hours and the solvent ratio of5:1(action:[Omim]Cl) in CO2/acetone/[Omim]Cl ternary system.