☰ MENU

Synthesis and purification of Ionic Liquids

Synthesis of Ionic Liquids


Protic Ionic Liquids (PILs)
Protic ionic liquid (PIL) is a subclass of ionic liquid that has a protonated cation and can be synthesized through a neutralization reaction which involves transferring a proton from a Brønsted acid to a Brønsted base.

B + A → HB+ + A-

  • PILs are a good conductor of protons and ions.

  • Water may be used as a solvents or titration can be performed without any solvent. Example

  • Complete proton transfer between the acid and base must occur for optimal production.

  • The cation on which the proton resides determines the proton activity of the IL.

  • To achieve this, there must be a high pKa difference between the acid and base.

  • In aqueous solutions, a difference greater than 10 is sufficient for more than 99% proton transfer.

  • Various factors, such as the physical and chemical properties of the base and acid determine the extent of proton transfer and ionicity of the IL.

  • A highly recommended procedure is to determine an acid-base titration curve for the two components dissolved in water.

  • The equivalence point and pH at the end point confirm the purity of the IL after synthesis and any subsequent handling procedures.

  • Diluting an IL sample in water to the standard concentration confirms the previously determined equivalence point pH.
Example:


(Click to close)
Titration curve:


(Click to close)

Copyright © 2022 - All Rights Reserved

Website by NECTAR-COST