摘要
采用反相气相色谱(IGC)技术研究了不同温度下1-烯丙基-3-甲基氯代咪唑([AMIM]Cl)的表面性质。以正己烷、正庚烷、正辛烷和正壬烷作为非极性探针分子测定[AMIM]Cl在343.15、353.15、363.15和373.15 K温度下的表面色散自由能;以二氯甲烷、三氯甲烷、丙酮、乙酸乙酯、四氢呋喃作为极性探针分子测定离子液体Lewis酸碱性质,并测定了吸附自由能和吸附自由焓变等热动力学参数。实验结果表明,[AMIM]Cl的酸解离平衡常数Ka为0.34,碱解离平衡常数Kb为1.68,其表面呈Lewis两性偏碱性特点。在343.15、353.15、363.15和373.15 K温度下,[AMIM]Cl的表面色散自由能分别为52.26、50.82、46.08和42.05 mJ/m2。这一结果对研究离子液体的表面性质及应用有指导作用。
The determination of the dispersive component of surface free energies (γds) at different temperatures and Lewis acid-base parameters of 1-allyl-3-methylimidazolium chloride ionic liquid ( [ AMIM ] C1) 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] C1 and the solvents. The IGC characterizations encompassed the adsorption thermodynamic parameters to acid-base surface interactions, including the standard enthalpy (AH~) and the free energy change of adsorption ( ΔGsa) at different temperatures. The results showed that the Lewis acid parameter Ks, of [ AMIM ] C1 was 0. 34, and the base parameter Kb, was I. 68, which indicated it was Lewis amphoteric with predominantly basic character. Furthermore, the free energy of adsorption AG: was also figured out. It was found that the γds of the [ AMIM ] C1 were 52.26, 50.82, 46.08 and 42.05 mJ/m2 at 343. 15, 353. 15, 353. 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.
出处
《色谱》
CAS
CSCD
北大核心
2013年第2期147-150,共4页
Chinese Journal of Chromatography
基金
新疆大学石油天然气精细化工重点实验室开放课题基金项目(XJDX0908-2010-05)
关键词
反相气相色谱
1-烯丙基-3-甲基氯代咪唑
离子液体
表面性质
表面色散自由能
Lewis酸碱参数
Key words: inverse gas chromatography (IGC)
1-allyl-3-methylimidazolium chloride
ionicliquid
surface properties
dispersive component of surface free energy
Lewis acid-baseparameters