Highly efficient extraction of phenols and aromatic amines into novel ionic liquids incorporating quaternary ammonium cation

Abstract

Two novel hydrophobic room temperature ionic liquids (RTIL) incorporating quaternary ammonium cations: tetrahexylammonium dihexylsulfosuccinate (THADHSS) and trioctylmethylammonium salicylate (TOMAS) have been obtained. The mutual solubility of the both RTILs with water and their Reichardt's polarity index have been measured. The extraction of aromatic amines and phenols into novel RTILs and two 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amides has been studied. The dependences of RTIL–water distribution ratio for the studied liquids on the phase volume ratio, the time of phase contact, pH value of aqueous solutions and the solute concentration have been obtained. In some cases, the solute distribution ratios for ammonium-based RTILs are as high as n × 10 4 that is much greater than for imidazolium ones. Notably, unlike the case of imidazolium-based RTILs, the quantitative extraction into ammonium RTILs is achieved even at the phase volume ratio V RTIL: V w = 1:20.