Alkenyl Functionalized Ionic Liquids

Functionalized ionic liquids are compounds with certain functions obtained by modifying the structure of anions and cations. Among them, by introducing different functional groups into organic cations, new ionic liquids can be designed. Olefinic compounds have unsaturated bonds that are prone to addition reactions. The introduction of ethylenic bonds can change the physicochemical properties of ionic liquids. At present, alkenyl functionalized ionic liquids are mainly ionic compounds prepared by introducing ethylenic bonds into imidazole groups to form cations. The introduction of ethylenic bonds can reduce viscosity, increase stability, increase conductivity, increase density, and realize applications in the biological, electrochemical, and fine chemical fields.

Figure 1. The chemical structure of common alkenyl functionalized ionic liquids

Applications:

• Degradation of cellulose: Due to its unique polarity, alkenyl functionalized ionic liquids have excellent solubility for biopolymers. The anion and cation of the low-viscosity ionic liquid have high ion mobility. This facilitates the interaction between ions and cellulose and promotes the dissolution of cellulose. The introduction of ethylenic bonds into the ionic liquid reduces its viscosity and speeds up the dissolution of cellulose. Furthermore, the existence of unsaturated bonds increases the electron deficiency of the cations, which is beneficial to the attack of the cations on the hydroxyl oxygen atoms on the cellulose during the dissolution process, and accelerates the completion of the degradation of the cellulose. Therefore, alkenyl functionalized ionic liquids can accelerate the degradation of cellulose.
• Electrochemical field: The alkenyl functionalized ionic liquids have double bonds that are prone to addition reactions. As a monomer for preparing polymer materials, the functionalized ionic liquid can be used to prepare polyionic liquid functional polymer through polymerization reaction. The obtained material overcomes the defect of easy leakage on the electrochemical device due to fluidity, and improves the safety and durability of the electrochemical device.
• Refined solvent oil: Solvent oils are widely used in chemical products and fine chemicals such as plastics, chemical fibers and rubber. Liquid-liquid extraction is a method of refining mineral spirits with simple operation and low energy consumption. In the selection of extractant, alkenyl functionalized ionic liquid can be widely used as a high-efficiency, clean and non-toxic extractant. The presence of ethylenic bonds improves the selectivity coefficient, increases the density, reduces the viscosity, and obtains a better separation effect.

Reference

• Cedric Maton,Neil R. Brooks,Luc Van Meervelt,Koen Binnemans,Stijn Schaltin,Jan Fransaer,Christian V. Stevens. Synthesis and Properties of Alkoxy- and Alkenyl-Substituted Peralkylated Imidazolium Ionic Liquids [J]. ChemPhysChem 2013, 15(14), 3503-3516.