摘要
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。
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 1 H-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.
引文
[1]Ozturk B,Yilmaz D.Absorptive removal of volatile organic[J].Process Safety and Environment Protection,2006,84(B5):391-398.
[2]Yun J H,Choi D K.Adsorption equilibria of chlorinated organic solvents onto activated carbon[J].Industrial and Engineering Chemistry Research,1998,37(4):1422-1427.
[3]Schlosser P M,Bale A S,Gibbons C F,et al.Human health effects of dichloromethane:key findings and scientific issues[J].Environmental Health Perspectives,2015,123(2):114-119.
[4]Yu J M,Cai W J,Chen J M,et al.Conversion characteristics and mechanism analysis of gaseous dichloromethane degraded by a VUV light in different reaction media[J].Journal of Environmental Sciences,2012,24(10):1777-1784.
[5]Shestakova M,Sillanpaa M.Removal of dichloromethane from ground and wastewater:a review[J].Chemosphere,2013,93(7):1258-1267.
[6]Borkar C,Tomar D,Gumma S.Adsorption of dichloromethane on activated carbon[J].Journal of Chemical and Engineering Data,2010,55:1640-1644.
[7]Lemus J,Martin-Martinez M,Palomar J.Removal of chlorinated organic volatile compounds by gas phase adsorption with activated carbon[J].Chemical Engineering Journal,2012,211/212:246-254.
[8]Zhou L,Zhang X H,Chen Y L.Facile synthesis of Al-fumarate metal-organic framework nano-flakes and their highly selective adsorption of volatile organic compounds[J].Materials Letters,2017,197:224-227.
[9]Zhou L,Zhang X H,Chen Y L.Modulated synthesis of zirconium metal-organic framework UiO-66 with enhanced dichloromethane adsorption capacity[J].Materials Letters,2017,197:167-170.
[10]Leng Y,Wang J,Zhu D R,et al.Heteropolyanion-based ionic liquids:reaction-induced self-separation catalysts for esterification[J].Angewandte Chemie International Edition,2009,48(1):168-171.
[11]Dong K,Liu X M,Dong H F,et al.Multiscale studies on ionic liquids[J].Chemistry Reviews,2017,117(10):6636-6695.
[12]Shang D W,Zhang X P,Zeng S J,et al.Protic ionic liquid[Bim][NTf2]with strong hydrogen bond donating ability for highly efficient ammonia absorption[J].Green Chemistry,2017,19(4):937-945.
[13]Zeng S J,Wang J,Bai L,et al.Highly selective capture of CO2 by ether-functionalized pyridinium ionic liquids with low viscosity[J].Energy Fuels,2015,29(9):6039-6048
[14]Che S Y,Dao R N,Zhang W D,et al.Designing an anionfunctionalized fluorescent ionic liquid as an efficient and reversible turn-off sensor for detecting SO2[J].Chemical Communications,2017,53(27):3862-3865.
[15]Yang D Z,Han Y L,Qi H B,et al.Efficient absorption of SO2 by EmimCl-EG deep eutectic solvents[J].ACS Sustainable Chemistry&Engineering,2017,5(8):6382-6386.
[16]Zeng S J,Zhang X C,Gao H S,et al.SO2-induced variations in the viscosity of ionic liquids investigated by in situ fourier transform infrared spectroscopy and simulation calculations[J].Industrial and Engineering Chemistry Research,2015,54(43):10854-10862.
[17]Wang J F,Petit C,Zhang X P,et al.Simultaneous measurement of CO2 sorption and swelling of phosphate-based ionic liquid[J].Green Energy&Environment,2016,1(3):258-265.
[18]Meng X C,Wang J Y,Jiang H C,et al.Guanidinium-based dicarboxylic acid ionic liquids for SO2 capture[J].Journal of Chemical Technology and Biotechnology,2017,92(4):767-774.
[19]Liu X Y,Huang Y,Zhao Y S,et al.Ionic liquid design and process simulation for decarbonization of shale gas[J].Industrial and Engineering Chemistry Research,2016,55(20):5931-5944.
[20]Zeng S J,Gao H S,Zhang X P,et al.Efficient and reversible capture of SO2 by pyridinium-based ionic liquids[J].Chemical Engineering Journal,2014,251:248-256.
[21]Li Z J,Zhang X P,Dong H F,et al.Efficient absorption of ammonia with hydroxyl-functionalized ionic liquids[J].RSC Advances,2015,5(99):81362-81370.
[22]Shang D W,Bai L,Zeng S J,et al.Enhanced NH3 capture by imidazolium-based protic ionic liquids with different anions and cation substituents[J].Journal of Chemical Technology and Biotechnology,2018,93(5):1228-1236.
[23]Lei Z G,Han J L,Zhang B F,et al.Solubility of CO2 in binary mixtures of room-temperature ionic liquids at high pressures[J].Journal of Chemical and Engineering Data,2012,57(8):2153-2159.
[24]Lei Z G,Dai C N,Chen B H.Gas solubility in ionic liquids[J].Chemistry Reviews,2014,114(2):1289-1326.
[25]Ando R A,Siqueira L J A,Bazito F C,et al.The sulfur dioxide-1-butyl-3-methylimidazolium bromide interaction:drastic changes in structural and physical properties[J].Journal of Physical Chemistry B,2007,111(30):8717-8719.
[26]Ren S H,Hou Y C,Wu W Z,et al.Properties of ionic liquids absorbing SO2 and the mechanism of the absorption[J].Journal of Physical Chemistry B,2010,114(6):2175-2179.
[27]Brown P,Gurkan B E,Hatton T A.Enhanced gravimetric CO2capacity and viscosity for ionic liquids with cyanopyrrolide anion[J].AIChE Journal,2015,61(7):2280-2285.
[28]Feldheim D L,Hendrickson S M,Krejcik M,et al.Kinetics of dichloromethane absorption into the conductive polymers[J].Journal of Physical Chemistry,1995,99(10):3288-3293.
[29]Borisch J,Pilkenton S,Miller L M,et al.TiO2 photocatalytic degradation of dichloromethane:an FTIR and solid-state NMR study[J].Journal of Physical Chemistry B,2004,108(18):5640-5646.
[30]Ding F,He X,Luo X Y,et al.Highly efficient CO2 capture by carbonyl-containing ionic liquids through lewis acid-base and cooperative C-HO hydrogen bonding interaction strengthened by the anion[J].Chemical Communications,2014,50(95):15041-15044.
[31]Noack K,Schulz P S,Paape N,et al.The role of the C2 position in interionic interactions of imidazolium based ionic liquids:a vibrational and NMR spectroscopic study[J].Physical Chemistry Chemical Physics,2010,12(42):14153-14161.
[32]Meng Z,Dolle A,Carper W R.Gas phase model of an ionic liquids:semi-empirical and Ab initio bonding and molecular structure[J].Journal of Molecular Structure:Theochem,2002,585:119-128.
