QCM法测定醇和酯蒸气在[Bmim][PF_6]中的溶解性能

Determination of solubility of alcohol and ester vapor in [Bmim][PF_6]by QCM method

利用石英晶体微天平(QCM)测定了4种典型的挥发性有机物(VOCs)——甲醇、乙醇、正丙醇和乙酸甲酯蒸气在疏水性离子液体1-丁基-3-甲基咪唑六氟磷酸盐([Bmim][PF_6])中的溶解行为。测定结果表明所测组分在[Bmim][PF_6]中均有较好的溶解性能,并受到组分与离子液体分子间作用力的影响,正丙醇溶解度>乙醇溶解度>甲醇溶解度>乙酸甲酯溶解度。重点考察了298.15~328.15K间不同压力对乙醇溶解性能的影响,其溶解度随压力升高、温度下降而增大,符合物理吸收特征。据此通过理论计算获得其亨利系数、溶解熵和焓等热力学数据,与实验数据一致。研究表明了QCM测定气体溶解度的可行性,该设备具有原料用量少、精度高等优点,为离子液体处理VOCs提供了参考。

The dissolution behaviors of four typical volatile organic compounds(VOCs),i.e.,methanol,ethanol, n-propanol and methyl acetate in the hydrophobic ionic liquid 1-butyl-3-methimidazole six fluorophosphate([Bmim][PF_6 ])are determined by the quartz crystal microbalance(QCM). The determination results show that the measured components have good solubility in [Bmim][PF_6]and are affected by the interaction between the group and the ionic liquid.The solubility is as follows:n-propanol>ethanol> methanol> methyl acetate.The effect of different pressure on the solubility of ethanol between298.15—328.15 K is mainly investigated. The solubility increases with the increase of pressure and temperature,which conforms to the characteristics of physical absorption. According to this,the thermodynamic data of Henry coefficient,dissolving entropy,enthalpy,etc.,are obtained by the theoretical calculation,which is in agreement with the experimental data.The research shows that QCM is feasible for the determination of gas solubility,and the device has the advantages of less raw material consumption and high accuracy,and also provides some reference for ionic liquid treatment of VOCs.