反气相色谱测定非对称双阳离子型离子液体的溶解度参数

在343.15~363.15 K下采用反气相色谱法对实验室合成的3种非对称双阳离子型离子液体PyC₅Pi]NTf₂]₂、MpC₅Pi]NTf₂]₂和PyC₆Pi]NTf₂]₂的溶解度参数进行了测定。以正辛烷、正癸烷、正十二烷、正十四烷和正十六烷作为探针溶剂,计算了在不同温度下探针溶剂在3种离子液体中的特性保留体积(V_g⁰)、摩尔吸收焓(ΔH₁^S)、无限稀释摩尔混合焓(ΔH_l^∞)、摩尔蒸发焓(ΔH_v)、无限稀释活度系数(Ω₁^∞)以及探针溶剂与3种离子液体的Flory-HuggirIs相互作用参数(χ₁₂^∞),得到了室温下3种离子液体的溶解度参数(δ₂)为28.52~32.66 (J·cm^-3)^1/2。分子结构中含有4-甲基吗啉比含有吡啶时溶解度参数更大。随着两个阳离子间连接基碳数的增加,溶解度参数增大。这一结果对研究离子液体的溶液性质和应用有指导作用。

Determination of solubility parameters for asymmetrical dicationic ionic liquids by inverse gas chromatography

Inverse gas chromatographic (IGC) technology was used to determine the solubility parameters of three asymmetrical dicationic ionic liquids (PyC₅Pi]NTf₂]₂, MpC₅Pi]NTf₂]₂ and PyC₆Pi]NTf₂]₂) at 343.15-363.15 K. Five alkanes were applied as test probes including octane (n-C₈), decane (n-C₁₀), dodecane (n-C₁₂), tetradecane (n-C₁₄), hexadecane (n-C₁₆). Some thermodynamic parameters were obtained by IGC data analysis, such as the specific retention volumes of the solvents (V_g⁰), the molar enthalpies of sorption (ΔH₁^s), the partial molar enthalpies of mixing at infinite dilution (ΔH_l^∞), the molar enthalpies of vaporization (ΔH_v), the activity coefficients at infinite dilution (Ω₁^∞), and Flory-Huggins interaction parameters (χ₁₂^∞) between ionic liquids and probes. The solubility parameters (δ₂) of the three dicationic ionic liquids at room temperature (298.15 K) were 28.52-32.66 (J·cm^-3)^1/2. The solubility parameters (δ₂) of cationic structure with 4-methyl morpholine are bigger than those of the cationic structure with pyridine. The bigger the solubility parameter (δ₂) is, the more the carbon numbers of linking group of the ionic liquids are. The results are of great importance to the study of the solution behavior and the applications of ionic liquid.