Abstract: Phenolic compounds, such as phenol, cresol and dimethyl phenol, are important substances and intermediates in industry. They are mainly derived from coal liquefaction oil and coal tar. At present, the traditional method to separate phenols from oil is aqueous alkali solution extraction, which consumes large amounts of NaOH and H₂SO₄ and produces a huge amount of phenol-contained waste water. This method results in high cost of separation and pollution controlling, which limits the recovery and application of phenolic compounds from coal liquefaction oil and coal tar. Therefore, it is necessary to develop a new method to use nonaqueous solution as extractant and to avoid using alkali aqueous solution. In this work, it is found that imidazolium based ionic liquids (ILs) are efficient media to extract phenols from toluene as simulated oil. [Bmim]Cl is better among different structure imidazolium based ILs, resulting from strong molecular interaction between IL and phenol. A small amount of [Bmim]Cl, equimolar to that of phenol in toluene, was enough to extract phenol from toluene with high extraction efficiency. The extraction was not sensitive to temperature and could be performed at room temperature. The extracted phenol in ILs could be recovered by vacuum evaporation at high temperatures, and the regenerated ILs could be reused for several cycles with almost same phenol extraction efficiency. [Bmim]Cl was also used to extract real coal liquefaction oil distillate with high extraction efficiency up to 92.5%, which has a potential application.

Key words: solvent extraction, separation recovery, ionic liquid, phenol, oil

摘要： 酚类化合物(如苯酚、甲酚和二甲酚等)是重要的化工原料和化工中间体，主要来自煤加氢液化油和中低温热解的煤焦油中。目前油中酚类化合物的分离方法主要是碱水洗脱法，这种方法不仅要消耗大量强碱、强酸，而且产生了大量含酚废水，导致分离成本和污染治理费用高，制约了煤液化油和煤焦油中酚类化合物的回收和利用。因此，有必要开发新的分离方法，避免使用酸碱溶液、采用非水相分离方法分离油中的酚类化合物。本文研究发现，卤咪唑基离子液体是一种高效的非水介质，可以用来萃取分离油中的酚类化合物。不同阴、阳离子结构的咪唑基离子液体萃取模拟油中苯酚表明[Bmim]Cl是较好的萃取剂，得因于它能形成较强的分子间相互作用。离子液体的用量与油中酚的量相当，用量少。在20~50℃的萃取温度内，温度对酚的萃取率影响很小。通过加热气提的方法可以使萃取酚后离子液体得到再生，并能重复使用，萃取率几乎不变。进一步将离子液体应用于真实油的酚类化合物的分离表明，咪唑基离子液体[Bmim]Cl萃取酚的效率可达92.5%，是一种具有潜在应用前景的萃取剂。

关键词: 溶剂萃取, 分离, 回收, 离子液体, 酚, 油