Amino Functionalized Ionic Liquids

The research of ionic liquids has a long history of development. With the expansion and in-depth research of ionic liquids, the development of ionic liquids has reached the stage of functionalized systems. Amino groups are common functional groups in organic compounds, which have the advantages of containing lone pairs of electrons, forming hydrogen bonds, and being easy to derivatize. Amino groups are common functional groups in organic compounds, which have the advantages of containing lone pairs of electrons, forming hydrogen bonds, and being easy to derivatize. Amino functionalized ionic liquids point to the introduction of amino functional groups into cations, giving ionic liquids unique properties and functions. Due to the introduction of amino groups, ionic liquids have excellent properties such as coordination ability, Lewis basicity and the ability to form hydrogen bonds with substrates, and are widely used in organic synthesis, adsorption and separation, etc.

Figure 1. Common structure of amino functionalized ionic liquids

Applications:

• Catalyst: Ionic liquids have been widely used as catalysts in organic synthesis. Different functionalized ionic liquids are suitable for different organic reactions. Amino functionalized ionic liquid has Lewis basicity and can effectively catalyze the condensation reaction of carbonyl compounds. In addition, the combined use of amino functionalized ionic liquids and transition metals acts as a base, ligand and reaction medium, which can effectively catalyze the cross-coupling reaction of olefin compounds.
• Enzyme immobilization: Enzyme-catalyzed reactions have high substrate specificity and selectivity, and are widely used in industries such as biotechnology, pharmaceuticals, food and washing. Immobilization of enzymes on mesoporous materials can improve the stability, acid and alkali resistance and service life of enzyme catalysts. Moreover, the introduction of ionic liquids can achieve better catalytic performance. Therefore, the use of ionic liquids to modify the mesoporous material to immobilize enzymes can prepare highly efficient catalysts. Amino functionalized ionic liquids can change the affinity/hydrophobicity and biological compatibility of the carrier, and improve the catalytic performance of the immobilized enzyme.
• CO₂ adsorbent: Amino groups have the advantage of easy derivatization and can be polymerized through polymerization. Ionic liquid polymers can improve the selectivity of absorbents and increase the adsorption capacity. The ionic liquid polymer prepared by using amino ionic liquid as a raw material has both chemical functional groups and solid microstructure, integrating physical adsorption and chemical adsorption, and is a class of CO₂ adsorbents with excellent performance.

Reference

• Sehee Kang,Yongchul G. Chung,Jo Hong Kang,Hojun Song. CO₂ absorption characteristics of amino group functionalized imidazolium-based amino acid ionic liquids [J]. Journal of Molecular Liquids 2020, 297, 111825.