疏水性离子液体萃取芳香化合物及其再生

Extraction of Aromatic Compounds with Hydrophobic Ionic Liquid and Its Regeneration

利用疏水性离子液体1-丁基-3-甲基咪唑六氟磷酸盐[Bmim][PF6]、1-丁基-3-乙基咪唑六氟磷酸盐[Beim][PF6]、1-丁基-3-甲基咪唑双三氟甲磺酰亚胺盐[Bmim][Tf2N]对水溶液中的9种芳香化合物进行萃取,以苯胺为代表对萃取工艺进行了优化,考察了乙醚、正丁醇等低极性溶剂对离子液体的再生情况.结果表明,在室温下,当相比O/A?0.2、时间为10 min时,[Bmim][PF6]对苯胺的萃取率达87.2%,分配系数为34.1,效果明显高于甲苯、正辛醇等传统有机溶剂.芳香化合物的分子结构对萃取有较大影响,萃取率及分配系数随溶质疏水性增加而增加.用乙醚作为反萃剂效果较好,苯胺和离子液体的回收率分别为93.1%和95.2%,溶质及离子液体均能实现资源化回收利用.

The performance of three kinds of hydrophobic ionic liquid, 1-butyl-3-methylimidazolium hexafluorophos phate [Bmim][PF6], 1-butyl-3-ethylimidazolium hexafluorophos phate [Beim][PF6] and 1-butyl-3-methylimidazolium bis[（trifluoromethyl）sulfonyl] imide [Bmim][TfzN], on extraction of aromatic compounds such as aniline and phenol derivatives from aqueous solution was investigated, aniline was primarily chosen as representative to optimize the extraction process, and the regeneration of [Bmim][PF6] was studied emphatically. The results showed that IL had good ability in the extraction with the partition coefficient as high as 34.1 when [Bmim][PF6] and aniline aqueous solution was mixed with the phase ratio of 0.2 and stirring for 10 min at 25 ℃. The partition coefficient was higher than the normal organic solvent such as toluene and 1-octanol. Molecular structure of aromatic compounds was found to have a great influence on the extraction. Due to the increase of the hydrophobicity of solute, the partition coefficient of aromatic compounds was increased. When diethyl ether was used as stripping agent, the recovery rate of aniline and IL was 93.1% and 95.2%, respectively. Both of aniline and IL could be recveled.