Linear polymeric ionic liquids as phase-transporters for both cationic and anionic dyes with synergic effects

Abstract

A series of linear polymeric ionic liquids were synthesized from synthetic polyester (PEP) and the following anion exchange reactions. The structure and properties of the obtained polymeric ionic liquids were characterized by ¹H NMR, FTIR, TGA and solubility tests. It was found that the obtained polymeric ionic liquid [PEP-MIM]DBS containing a cationic imidazole group and anionic DBS on the side chain was soluble in chloroform and was demonstrated to be a very effective transporter for the anionic dye methyl orange (MO) and cationic dye methylene blue (MB) from the water phase to the chloroform phase individually as well as simultaneously. The transfer efficiency reached 92% for MO and 80% for MB in the phase-transfer of the single dye. In addition, the phase-transfer experiments of the MO/MB mixed solution showed that the absence of MO improved the transfer efficiency of MB by 20% compared with the single solution.