Synthesis of Monomeric Ionic Liquids Based on 4-Vinylbenzyl Chloride as Precursors of a Material for the Selective Layer of Gas Separation Membranes

Monomeric ionic liquids (MILs) that are based on 4-vinylbenzyl chloride and contain an ammonium cation (VBTEA–Cl, MIL 1) and a pyridinium cation (VBPy–Cl, MIL 2) have been synthesized in accordance with an ingenious solvent-free procedure providing the formation of target products with a yield higher than 90%. Using compounds with a chloride anion, new ionic liquids containing an organic bis(trifluoromethylsulfonyl)imide anion—VBTEA–Tf2N (MIL 3) and VBPy–Tf2N (MIL 4)—have been synthesized by the anion-exchange reaction with high yields (95%). Monomeric ionic liquids 1–4 have been characterized by spectral methods (NMR and IR spectroscopy). The synthesized MILs can be used as precursors for the formation of a polymer selective layer for gas separation membranes. The bis(trifluoromethylsulfonyl)imide anion contained in the compounds provides a facilitated transport owing to a specific interaction with acid gas molecules.