Purification of Ionic Liquid [mTBDH][OAc] Utilizing the Short-Path Distillation Technique.

Area of Science:

• Textile Chemistry
• Green Chemistry
• Chemical Engineering

Background:

• The Ioncell process uses ionic liquids (ILs) for sustainable textile production.
• Impurities in ILs negatively impact cellulose dissolution and process efficiency.
• Purification of the IL 7-Methyl-1,5,7-triazabicyclo[4.4.0]-dec-5-enium acetate ([mTBDH]-[OAc]) is essential for process sustainability.

Purpose of the Study:

• To investigate the purification of [mTBDH]-[OAc] in the presence of various impurities.
• To understand IL-impurity interactions for effective base recovery and IL purification.
• To optimize purification conditions for a closed-loop Ioncell process.

Main Methods:

• Utilized short path distillation (SPD) to purify [mTBDH]-[OAc].
• Introduced impurities including KCl, NaCl, CaCl2, lactic acid, xylan, and hydrolysis products (H-mTBD-1, H-mTBD-2).
• Varied feed flow rate during SPD to assess the recovery of the base 7-Methyl-1,5,7-triazabicyclo(4.4.0)-dec-5-ene (mTBD).

Main Results:

• Highest recovery fractions (0.97-1.00) of mTBD were achieved at the lowest flow rate (0.378 kg/h).
• Approximately 75-100% of the base mTBD was recovered under most experimental conditions.
• SPD effectively removed inorganic salts (K, Na, Ca), xylan, and lactic acid from the IL feed.

Conclusions:

• Short path distillation is an effective method for purifying [mTBDH]-[OAc] for the Ioncell process.
• Optimized SPD conditions enable high recovery of the valuable base mTBD.
• This purification strategy enhances the sustainability of IL-based textile production by minimizing waste and maximizing resource utilization.