Centre for Green Chemistry and Catalysis, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, China.
Phys Chem Chem Phys. 2010 Feb 28;12(8):1971-81. doi: 10.1039/b920556j. Epub 2010 Jan 25.
A series of nanocomposites of ionic liquids (ILs) were prepared via a modified sol-gel method. The ILs were physically confined in mesoporous silica gels with 5-40% content. ILs from imidazolium, thiophenium and ammonium with different anions were prepared and used. Characterization using the Brunauer-Emmett-Teller (BET) method, Fourier transform infrared (FT-IR) spectroscopy, temperature-programmed desorption (TPD), differential scanning calorimetry (DSC), inverse gas chromatography (IGC), temperature-controlled Raman and fluorescence emission spectroscopies was conducted to explore any confinement effects. BET results showed that, depending on the ILs and their contents, the average pore diameter of the pure silica gel was 3-12 nm after the confined ILs were removed completely. It was suggested that ILs aggregated on the nanoscale in the mesoporous silica gel. In comparison with bulk ILs and ILs coated onto silica gels (IL/sg), IL nanocomposites (IL-sg) displayed remarkably low specific heat capacities (C(p) was in the range 0.3-1.2 J g(-1) K(-1)), disordered vibrational conformations (without phase transitions in the range -100-200 degrees C), greater interactions with hydrocarbon solutes (adsorption capacities of 0.3-0.4 g per 100 g for confined ILs with CO(2) gas), and greatly enhanced fluorescence emission (up to 200 times stronger than bulk ILs). Furthermore, Based on the specific solubility of different compounds, the nanocomposites could also be applied to the separation of CO(2) from CO(2)/N(2) mixtures and thiophene from thiophene/octane mixtures.
通过改进的溶胶-凝胶法制备了一系列离子液体（ILs）的纳米复合材料。将 ILs 物理限制在具有 5-40％含量的中孔硅凝胶中。制备并使用了不同阴离子的咪唑鎓、噻吩鎓和铵基 ILs。使用 Brunauer-Emmett-Teller（BET）方法、傅里叶变换红外（FT-IR）光谱、程序升温脱附（TPD）、差示扫描量热法（DSC）、反气相色谱（IGC）、控温拉曼和荧光发射光谱进行了表征，以探索任何限制效应。BET 结果表明，根据 ILs 及其含量，在完全去除被限制的 ILs 后，纯硅胶的平均孔径为 3-12nm。这表明 ILs 在介孔硅胶中在纳米尺度上聚集。与块状 ILs 和涂覆在硅胶上的 ILs（IL/sg）相比，IL 纳米复合材料（IL-sg）显示出非常低的比热容量（C(p)在 0.3-1.2Jg(-1)K(-1)范围内）、无序的振动构象（在-100-200°C 范围内没有相变）、与碳氢化合物溶质的相互作用更大（对于 CO(2)气体的被限制的 ILs，吸附能力为 0.3-0.4g 每 100g），并且荧光发射大大增强（比块状 ILs 强 200 倍以上）。此外，基于不同化合物的特殊溶解度，纳米复合材料还可应用于从 CO(2)/N(2)混合物中分离 CO(2)和从噻吩/辛烷混合物中分离噻吩。
