CO_(2)捕集是实现碳减排的重要技术之一。其中,化学吸收法是一种有效的、适用于低CO_(2)分压的CO_(2)捕集技术。开发出一种高效、低能耗、环保的吸收剂是该领域的研究难点和热点。离子液体(ILs)作为一类绿色溶剂,在CO_(2)捕集中具有结...CO_(2)捕集是实现碳减排的重要技术之一。其中,化学吸收法是一种有效的、适用于低CO_(2)分压的CO_(2)捕集技术。开发出一种高效、低能耗、环保的吸收剂是该领域的研究难点和热点。离子液体(ILs)作为一类绿色溶剂,在CO_(2)捕集中具有结构可调节、反应速率快、吸收量高等优势,但存在黏度大、价格昂贵等问题,本工作提出将超强碱离子液体1,8-二氮杂二环[5,4,0]十一碳-7-烯咪唑([HDBU][Im])与单乙醇胺(MEA)复配得到离子液体复配溶剂,来提高吸收剂的CO_(2)吸收量并降低吸收CO_(2)后溶剂的黏度。研究了离子液体浓度、吸收温度、CO_(2)分压等对离子液体复配溶剂捕集CO_(2)性能的影响,测定了离子液体复配溶剂在不同CO_(2)负荷下的密度和黏度等物性。结果表明,30wt%MEA+10wt%[HDBU][Im]具有较好的吸收能力,在40℃下,CO_(2)吸收量达到0.1453 g CO_(2)/g溶剂,且吸收CO_(2)前后溶剂的黏度分别为2.312和4.303 mPa·s,显著低于离子液体吸收剂,是一种具有潜力的CO_(2)捕集溶剂。展开更多
The theoretical calculation and spectroscopic experiments indicate a kind of triangular three bonding supramolecular complexes CBr4…X^-…-H-C, which consist of carbon tetrabromide, halide, and protic solvent molecule...The theoretical calculation and spectroscopic experiments indicate a kind of triangular three bonding supramolecular complexes CBr4…X^-…-H-C, which consist of carbon tetrabromide, halide, and protic solvent molecule （referring to dichloromethane, chloroform and acetonitrile）, can be formed in solution. The strength of halogen and hydrogen bonds in the triangular complexes using halide as common acceptor obeys the order of iodide〉bromide〉chloride. The halogen and hydrogen bonds work weak-cooperatively. Charge transfer bands of halogen bonding complexes between CBra and halide are observed in UV-Vis absorption spectroscopy in three solvents, and then the stoichiometry of 1：1, formation constants K and molar extinction coefficients ε of the halogen bonding complexes are obtained by Benesi-Hildebrand method. The K and ε show a dependence on the solvent dielectric constant and, on the whole, obey an order of iodide〉bromide〉chloride in the same solvents. Furthermore, the C-H vibrational frequencies of solvent molecules vary obviously with the addition of halide, which indicates the C-H…X- interaction. The experimental data indicate that the halogen bond and hydrogen bond coexist by sharing a common halide acceptor as predicted by calculation.展开更多
文摘CO_(2)捕集是实现碳减排的重要技术之一。其中,化学吸收法是一种有效的、适用于低CO_(2)分压的CO_(2)捕集技术。开发出一种高效、低能耗、环保的吸收剂是该领域的研究难点和热点。离子液体(ILs)作为一类绿色溶剂,在CO_(2)捕集中具有结构可调节、反应速率快、吸收量高等优势,但存在黏度大、价格昂贵等问题,本工作提出将超强碱离子液体1,8-二氮杂二环[5,4,0]十一碳-7-烯咪唑([HDBU][Im])与单乙醇胺(MEA)复配得到离子液体复配溶剂,来提高吸收剂的CO_(2)吸收量并降低吸收CO_(2)后溶剂的黏度。研究了离子液体浓度、吸收温度、CO_(2)分压等对离子液体复配溶剂捕集CO_(2)性能的影响,测定了离子液体复配溶剂在不同CO_(2)负荷下的密度和黏度等物性。结果表明,30wt%MEA+10wt%[HDBU][Im]具有较好的吸收能力,在40℃下,CO_(2)吸收量达到0.1453 g CO_(2)/g溶剂,且吸收CO_(2)前后溶剂的黏度分别为2.312和4.303 mPa·s,显著低于离子液体吸收剂,是一种具有潜力的CO_(2)捕集溶剂。
基金ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China （No.20675009 and No. 90922023）. The basis set aug-cc-pVDZ-PP for iodine atom is downloaded at the website http：//bse.pnl.gov/ bse/portal.
文摘The theoretical calculation and spectroscopic experiments indicate a kind of triangular three bonding supramolecular complexes CBr4…X^-…-H-C, which consist of carbon tetrabromide, halide, and protic solvent molecule （referring to dichloromethane, chloroform and acetonitrile）, can be formed in solution. The strength of halogen and hydrogen bonds in the triangular complexes using halide as common acceptor obeys the order of iodide〉bromide〉chloride. The halogen and hydrogen bonds work weak-cooperatively. Charge transfer bands of halogen bonding complexes between CBra and halide are observed in UV-Vis absorption spectroscopy in three solvents, and then the stoichiometry of 1：1, formation constants K and molar extinction coefficients ε of the halogen bonding complexes are obtained by Benesi-Hildebrand method. The K and ε show a dependence on the solvent dielectric constant and, on the whole, obey an order of iodide〉bromide〉chloride in the same solvents. Furthermore, the C-H vibrational frequencies of solvent molecules vary obviously with the addition of halide, which indicates the C-H…X- interaction. The experimental data indicate that the halogen bond and hydrogen bond coexist by sharing a common halide acceptor as predicted by calculation.
