The effect of the addition of 1-butyl-3-methylimidazolium tetrafluoroborate （[C4mim][BF4]） on the formation rates of CO2 hydrates was investigate. The isothermal and isobaric methods were used to measure the formation rates of CO2 hydrates. As compared to those of pure water, the data of phase equilibrium changed greatly. The effects of pressure, temperature, and the concentration of [C4mim][BF4] aqueous solution on the formation rates of CO2 hydrates were investigated. With a constant concentration of [C4mim][BF4], the rate of gas consumption was enhanced with the lowering of experimental temperature. However, a decrease in pressure exerted an opposite effect on the rate of gas consumption. Moreover, the addition of [C4mim][BF4] raised the equilibrium pressure of hydrate formation at the same temperature.
Qi ChenYong YuPeng ZengWei YangQianqing LiangXiaoming PengYansheng LiuYufeng Hu
The solubility of β-cyclodextrin （β-CD） in ionic liquid/N, N-dimethyl-acetamide （IL/DMAC） mixed solvent and in LiCI/DMAC mixed solvent was investigated at 323.15 K and 353.15 K. The results showed that the solubility of β-CD in IL/DMAC system increased with increasing temperature, but decreased in LiCI/DMAC system. β-CD had the highest solubility in IL/DMAC system with [Cl]- or [Br]- anions. The solubility of β-CD in LiCl/DMAC system was lower than that in IL/DMAC system with [Cl]- or [Br]- anions but higher than that in IL/DMAC system with weak-coordinated anions （e.g [BF4]- or [PF6]-）. The effects of substituent groups （benzyl and butyl） of cation and the structure of cations on β-cyclodextrin solubility were also investigated.
Yu Yong Li Jiguang Sun Yan Liang Qianqing Peng Xiaoming Liu Yansheng Hu Yufeng
The extractive removal of sulfur compounds （S-compounds） from Dongying and Liaohe diesel fuels with [BF4]^--based ionic liquids were systematically investigated. The results show that the absorption capacity of an ionic liquid for the S-compounds in diesel fuels relies on its structure and its size. In the case of the two examined diesel fuels, both elongating the cation tail length and increasing the mass ratio of ionic liquid/diesel fuel promote the desulfurization ability of the examined ionic liquids. The results also show that imidazolium-based ionic liquids display higher extraction efficiencies than pyridinium-based ionic liquids, presumably owing to the fact that the rings of the S-compounds are similar to the imidazolium head ring. With the 1 ： 1 mass ratio of ionic liquid/diesel fuel, the rates of the first desulfurization of Dongying and Liaohe diesel fuels using [C8mim][BF4] amount to 29.96% and 39.76%, suggesting that [C8mim][BF4] is a promising extractant for desulfurization of these diesel fuels.
Ionic liquids （ILs） have been regarded as the potential novel solvents for improved analytical- and process-scale separation methods.The development of methods for the recovery of ILs from aqueous solutions to escape contamination and recycle samples will ultimately govern the viability of ILs in the future industrial applications. Therefore, in this paper a new method for separation of ILs from their dilute aqueous solutions and simultaneously purification of water was proposed on the basis of the CO2 hydrate formation. For illustration, the dilute aqueous solutions with concentrations of ILs ranging from 2× 10^-3 mol% to 2×10^-1 mol% were concentrated. The results show that the separation efficiency is very impressive and that the new method is applicable to aqueous solutions of both hydrophobic and hydrophilic ILs. Compared to the literature separation method based on the supercritical CO2, the new method is applicable to lower concentrations, and more importantly, its operation condition is mild.
Xiaoming PengYufeng HuYansheng LiuChuanwei JinHuaijing Lin
