N-vinylimidazoles Ionic Liquids

Disubstituted imidazolium-based ionic liquids can be simply divided into N-methylimidazole ionic liquids and N-vinylimidazole ionic liquids according to the different substituents on the nitrogen atom. The introduction of vinyl functional groups endows imidazole ionic liquids with special properties, making them have the advantages of easy addition of imidazole ionic liquids and vinyl bonds. N-vinylimidazole ionic liquids with special properties can be used in more refined fields, such as the dissolution and processing of specific cellulose, the recognition of bovine hemoglobin, the modification of flame-retardant materials, and the preparation of polymer electrolytes.

Figure 1. Common chemical structures of N-vinylimidazole ionic liquids

Applications:

• Dissolution and processing of cellulose: N-vinylimidazole ionic liquids have the advantages of low melting point, low viscosity and good thermal stability, and can quickly dissolve cellulose in a short time. The presence of the double bond in the imidazole cation increases the electron deficiency of the cation, prompts it to attack the oxygen atom on the cellulose hydroxyl group, and accelerates the dissolution of cellulose. N-vinylimidazole ionic liquids can also be used as reaction solvents to prepare cellulose fibers and cellulose films.
• Recognition of bovine hemoglobin: Molecular imprinting technology is a separation and purification technology in which specific molecules and functional monomers are polymerized together in a solution under the action of a crosslinking agent to obtain polymers. Then remove the specific molecule by a suitable method and retain the three-dimensional structure of the specific molecule, so as to realize the recognition of the specific molecule. As an organic salt, N-vinylimidazole ionic liquid can be used for the separation and purification of bovine hemoglobin in combination with molecular imprinting technology, showing good selection effect and stability.
• Improved performance of flame retardant coatings: UV curing epoxy acrylate coating has the advantages of fast curing, high hardness, environmental protection and energy saving, chemical corrosion resistance, etc., and can be used as a transparent flame-retardant coating. N-vinylimidazole ionic liquids can improve the flame retardancy and transparency of epoxy acrylate polymers as modifiers.
• Application of polymer electrolyte: The polymer electrolyte can eliminate the shortcomings of liquid electrolyte leakage, flammability, and poor stability. Ionic liquids with ethylenic bonds can be prepared into polymer electrolytes through polymerization reactions. Using the cation of N-vinylimidazole as a monomer and azobisisobutyronitrile as an initiator, a rubber-like material with a low glass transition temperature can be obtained. The material can increase the ion conductivity and improve the conversion efficiency of the battery.

Reference

• Csaba Fodor, Bernadetta Gajewska, Omar Rifaie-Graham,Edward A. Apebende, Jonas Pollard, Nico Bruns. Laccase-catalyzed controlled radical polymerization of N-vinylimidazole [J]. Polym. Chem., 2016, 7, 6617-6625.