咪唑类离子液体高效吸收二氯甲烷

合成了一系列常规离子液体1-丁基-3-甲基咪唑四氟硼酸盐(Bmim]BF4])、1-丁基-3-甲基咪唑六氟磷酸盐(Bmim]PF6])、1-丁基-3-甲基咪唑双三氟甲磺酰亚胺盐(Bmim]NTf2])、1-丁基-3-甲基咪唑双氰胺盐(Bmim]DCA])、1-丁基-3-甲基咪唑硫氰酸盐(Bmim]SCN])、1-乙基-3-甲基咪唑硫氰酸盐(Emim]SCN])和N-丁基吡啶硫氰酸盐(BPy]SCN])，用智能重量分析仪(IGA)测定不同温度和分压下离子液体吸收二氯甲烷(DCM)的容量。结果表明，Bmim]SCN]具有最高的二氯甲烷吸收容量(1.46 g/g, 303.15 K, 60 kPa)，5次循环后吸收能力无明显下降，Bmim]SCN]基本可完全再生，能循环使用。量化计算结果表明SCN]?可与二氯甲烷形成氢键，增强其对二氯甲烷的吸收能力。

Efficient absorption of dichloromethane using imidazolium based ionic liquids

In recent years, environment problems have been a hot issue of concern to the public. Chlorinated volatile organic compounds such as dichloromethane (DCM) have been a serious threat to the public health and environment as hazardous chemical substances. Solving these problems has become an urgent issue in nowadays society. Ionic liquids (ILs) are supposed to be potential solvents to absorb gases due to their unique structures and properties, which have exhibited excellent absorption capacity in NH3, SO2, CO2 and other gases. In this paper, a series of conventional ILs including Bmim]BF4], Bmim]PF6], Bmim]DCA], Bmim]SCN], Bmim]NTf2], Emim]SCN], BPy]SCN] were synthesized and used as absorbents for dichloromethane (DCM) capture at different temperatures and partial pressures. The absorption capacities of DCM by ILs were measured by a highly sensible microbalance-intelligent gravimetric analyzer (IGA). It was found that Bmim]SCN] has the highest absorption capacity to DCM (1.46 g/g, 303.15 K, 60 kPa) among these investigated ILs, and the absorption capacity of Bmim]SCN] had no obvious decline after five absorption?desorption cycles. The densities and viscosities of Bmim]SCN] with different mass fraction of DCM absorbed were measured in this work as well. And with the increase of the mass fraction of DCM absorbed, the density of DCM absorbed Bmim]SCN] increased slightly, while the viscosity decreased dramatically. In addition, mechanism of DCM absorption by Bmim]SCN] was investigated through FT-IR and 1H?NMR, implying the interaction between DCM and Bmim]SCN] was physical interaction. Furthermore, the interactions between cations or anions of ILs and DCM were investigated by quantum chemical calculation, which demonstrated that the anions of ILs had a more significant influence on the absorption capacity than cations, on account of the strong hydrogen bond interaction between anion and DCM, which has a great agreement with the results of experiment. This work will provide a new sight for designing more competitive ILs for DCM capture.