Liquid−Liquid Equilibria in Binary Mixtures Containing Substituted Benzenes with Ionic Liquid 1-Ethyl-3-methylimidazolium Bis(trifluoromethylsulfonyl)imide

Abstract

Liquid−liquid equilibria in binary mixtures of substituted benzenes (toluene, ethylbenzene, propylbenzene, xylene isomers, trimethylbenzene isomers, aniline, nitrobenzene, phenol, and benzaldehyde) with ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf2N]), have been measured using a mass–volume technique over a temperature range from about (293 to 373) K. Trends in both the polarity and molecular size of the solute with the immiscibility gap were discovered for the alkyl-substituted benzenes. In general, as the polarity increased and the molecular size decreased, the immiscibility gap became smaller. The nonalkyl-substituted benzenes containing functional groups (−NH2, −NO2, −OH, and −CHO) were completely soluble in [emim][Tf2N] over the composition and temperature range studied. The excess molar volumes for the ionic liquid-rich side solutions range from (−1 to −5) cm3·mol−1, and the magnitudes are somewhat larger than those of ordinary liquid solutions. Observed LLE are well correlated by use of the nonrandom two liquid (NRTL) solution model.