6533b827fe1ef96bd1286496

RESEARCH PRODUCT

Potential of phosphonium-based ionic liquids to purify 1-propanol from water by liquid–liquid extraction at mild conditions

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Abstract In order to reduce the environmental of the separation of 1-propanol from water in a residual industry stream for its reuse, the capability as solvents of two different trihexyl(tetradecyl)phosphonium ionic liquids (ILs) – trihexyl(tetradecyl)phosphonium chloride ([TDTHP][Cl]) and trihexyl(tetradecyl)phosphonium bromide ([TDTHP][Br])-, was studied. The liquid–liquid equilibria data for both ternary systems, {water + 1-propanol + [TDTHP][Cl]} and {water + 1-propanol + [TDTHP][Br]} at different mild work temperatures, (283.2, 303.2 and 323.2) K, and atmospheric pressure were measured. The thermodynamic parameters for both ternary systems at different work conditions were obtained by the non-random two-liquid activity coefficient model (NRTL) in order to achieve a posterior correct equipment design. Finally, the selectivity and distribution coefficient of [TDTHP][Cl] and [TDTHP][Br] were bibliographically benchmarked with different ILs, trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl)phosphinate ([TDTHP][Phosph]) and 1-decyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([dmim][Tf2N]), achieving a solubility of 1-propanol in the IL around 20 times greater than in water and a capability of [TDTHP][Br] to incorporate 1-propanol in its phase instead of in water rich phase around 40, which means, a great selectivity and values of the distribution coefficient close to the double in respect to the ILs researched. It could be concluded that both ILs, [TDTHP][Cl] and [TDTHP][Br], are capable to purify 1-propanol from water with great technical, environmental and economic advantages, in respect of the classical solvents and other ILs researched.