Chen Yali, Wang Qiang, Deng Lishuang, Zhang Zhengfang, Tang Jun
Center for Physical and Chemical Analysis, Xinjiang University, Urumqi 830046, China.
Se Pu. 2013 Feb;31(2):147-50. doi: 10.3724/sp.j.1123.2012.10006.
The determination of the dispersive component of surface free energies (gamma(s)d) at different temperatures and Lewis acid-base parameters of 1-allyl-3-methylimidazolium chloride ionic liquid ([AMIM]Cl) were investigated by means of inverse gas chromatography (IGC). Four n-alkanes, including n-hexane (C6), n-heptane (C7), n-octane (C8) and n-nonane (C9), were chosen as the apolar probes to characterize the dispersive component of the surface free energies at 343.15, 353.15, 363.15 and 373.15 K, respectively; and dichloromethane (DCM), trichloromethane (TCM), tetrahydrofuran (THF), ethyl acetate (EtAc), acetone (Acet) as the polar probes to estimate the Lewis acid-base parameters to judge the interactions between [AMIM] Cl and the solvents. The IGC characterizations encompassed the adsorption thermodynamic parameters to acid-base surface interactions, including the standard enthalpy (deltaHa(s)) and the free energy change of adsorption (deltaGa(s)) at different temperatures. The results showed that the Lewis acid parameter Ka of [AMIM] Cl was 0.34, and the base parameter Kb was 1.68, which indicated it was Lewis amphoteric with predominantly basic character. Furthermore, the free energy of adsorption deltaGa(s) was also figured out. It was found that the gamma(s)d of the [AMIM] Cl were 52.26, 50.82, 46.08 and 42.05 mJ/m2 at 343.15, 353.15, 363.15 and 373.15 K, respectively. The results are of great importance to the study of the surface properties and the application of ionic liquid.
通过反相气相色谱法（IGC）研究了1-烯丙基-3-甲基咪唑氯化物离子液体（[AMIM]Cl）在不同温度下表面自由能的色散分量（γ(s)d）以及路易斯酸碱参数。选择了四种正构烷烃，包括正己烷（C6）、正庚烷（C7）、正辛烷（C8）和正壬烷（C9）作为非极性探针，分别在343.15、353.15、363.15和373.15 K下表征表面自由能的色散分量；并选择二氯甲烷（DCM）、三氯甲烷（TCM）、四氢呋喃（THF）、乙酸乙酯（EtAc）、丙酮（Acet）作为极性探针来估算路易斯酸碱参数，以判断[AMIM]Cl与溶剂之间的相互作用。IGC表征涵盖了酸碱表面相互作用的吸附热力学参数，包括不同温度下的标准焓（ΔHa(s)）和吸附自由能变化（ΔGa(s)）。结果表明，[AMIM]Cl的路易斯酸参数Ka为0.34，碱参数Kb为1.68，表明它是具有主要碱性特征的路易斯两性物质。此外，还计算出了吸附自由能ΔGa(s)。发现[AMIM]Cl在343.15、353.15、363.15和373.15 K下的γ(s)d分别为52.26、50.82、46.08和42.05 mJ/m2。这些结果对于离子液体表面性质的研究和应用具有重要意义。
