Halogen-free ionic liquids as high performance extractants for phenols separation.

Area of Science:

• Chemical Engineering
• Materials Science

Background:

• Phenols are valuable chemical raw materials used in pharmaceuticals, new materials, and engineering products.
• Efficient separation of phenols from oil mixtures holds significant economic importance.

Purpose of the Study:

• To design and evaluate halogen-free ionic liquids (HFILs) for effective phenol separation from simulated oil mixtures.
• To identify the most efficient HFIL and characterize its performance metrics.

Main Methods:

• Design and synthesis of five novel HFILs.
• Application of HFILs for phenol separation from simulated oils.
• Analysis of separation efficiency, distribution coefficient, and purity using techniques like FT-IR spectroscopy.
• Regeneration and reuse studies of the HFILs.

Main Results:

• All five designed HFILs demonstrated excellent phenol separation performance.
• 1-ethyl-3-methylimidazolium acetate ([Emim][Ac]) achieved the highest separation efficiency (98.6%) and a low ultimate phenol content (1.96 g dm⁻³).
• High distribution coefficient (431.8) and effective separation of different phenol types were observed. The process was rapid (3 min) and operated at normal temperature.

Conclusions:

• Halogen-free ionic liquids, particularly [Emim][Ac], are highly effective for separating phenols from oils.
• The HFILs are recyclable and reusable for at least 6 cycles without efficiency loss.
• FT-IR analysis suggests hydrogen bonding plays a role in the separation mechanism.