The dissolution of petroleum asphaltenes with ionic liquids is studied for the first time. The results show that the ionic liquids could be used as novel solvents for asphaltenes. The important parameters governing the ability of ionic liquids for dissolution of asphaltenes are discussed. It is found that, the ionic liquids based on the cations containing a conjugated aromatic core or the anions which are strong hydrogen bond acceptors are most effective, whereas the ionic liquids containing ＇non coordinating＇ anions such as [BF4]^- and [PF6]^- are nonsolvents for asphaltenes. Increase in the effective anion charge density enhances the ability of ionic liquids to break the extensive asphaltene associations and thus enhances the solubility of asphaltenes in the ionic liquid. The dissolution ability of ionic liquid decreases apparently with increasing the substituted alkyl chain length of its cationic head ring. Temperature is found to play an important role on dissolution of asphaltenes, and the dissolution can be significantly imoroved bv microwave heatinz.
To check the applicabilities of the simple density equation and viscosity equation in the semi-ideal solution theory to nonelectrolyte solutions, the densities and viscosities were measured for the quaternary system mannitol-sorbitol-D-glucose-HzO and its ternary subsystems mannitol-D-glucose-H2O and sorbitol-D-glucose-H2O at 298.15K. The results were used to test the applicability of the simple equations for the density and viscosity of the multicomponent nonelectrolyte solution. The agreements between the predicted and measured results are good.
The simple equation relating the activity coefficient of each solute in mixed electrolyte solution to its value in binary solutions under isopiestic equilibrium was tested by comparison with the experimental data for the 18 electrolyte solutions consisting of 1：1, 1：2, and 1：3 electrolytes. The isopiestic measurements were made on the quaternary system BaCl2-NH4Br-NaI-H2O and its ternary subsystems NaI-NH4Br-H2O, NaI-BaCl2-H2O, and NH4Br-BaCl2-H2O at 298.15K. The results were used to test the applicability of the Zdanovskii＇s rule to the mixed electrolyte solutions which contain no common ions, and the agreement is excellent. The activity coefficients of the solutes in the above quaternary and ternary systems calculated from the above-mentioned simple equation are in good agreement with the Pitzer＇s equation.
The effects of the structure of typical cations and anions of ionic liquids on the separation of benzene and toluene from aromatic/paraffin mixtures were studied. The .results showed that the corresponding separation factors were considerably larger than those of the traditional solvents （Benzene＋Hexane＋sulfolane）, and that the ionic liquids could be used as novel solvents for the separation of aromatics from hydrocarbon mixtures. The key parameters governing the ability of ionic liquids for separating aromatics from hydrocarbon sources were investigated. It was found that the effectiveness of the ionic liquids, based on the same anion, changed in the cation order of [BIqu]^＋〈 [BPy]^＋〈 [BMIM]^＋. The selectivity of the ionic liquid toward aromatics decreased apparently with the increasing length of the substituted alkyl chain of its cationic head ring. The separation factors, based on the same cation, changed in the anion order of [Tf2N]^-〈[PF6]^-〈[BF4]^-〈[C2H5SO4]^-. The solubilities of the aromatics were greater in the ionic liquids based on the former three anions than that in the ionic liquids involving [C2H5SO4]^-.
Liu Yansheng Zhang Zhongxin Zhang Guofu Liu Zhichang Hu Yufeng Shi Quan Ji Dejun
The equation of Patwardhan and Kumar for water activities of mixed electrolyte solutions is extended to aqueous solutions containing non-electrolytes. This equation and the linear isopiestic relation are used to predict water activities of 56 ternary aqueous solutions in terms of the data of their binary subsystems. Both equation of Patwardhan and Kumar and the linear isopiestic relation can provide good predictions for water activities of the present 40 electrolyte solutions, and the linear isopiestic relation generally yields better predictions. The predictions of the extended equation of Patwardhan and Kumar and the linear isopiestic relation are in general quite reasonable for the present 8 ternary solutions of electrolytes and non-electrolytes, and the results of the linear isopiestic relation are usually better. The predictions of these two methods generally agree well with the experimental data for the 8 non-electrolyte mixtures being studied, and the linear isopiestic relation is better.
