溴化N-乙基吡啶+水+盐体系的相行为

Phase behavior of N-ethyl-pyridinium bromide ionic liquid+water+salt aqueous two-phase systems

测定了298.15 K时的离子液体溴化N-乙基吡啶([EPy]Br)+盐(酒石酸钾钠C4O6H4KNa、磷酸氢二钾K2HPO4)离子液体双水相体系的双节线和系线的相关数据,探讨了双水相体系的形成机理和条件,并通过双节线模型计算出了双水相体系的有效排除体积(EEV),得到了磷酸氢二钾的盐析能力更强的结论。实验的双节线数据利用Merchuk等非线性方程成功关联,系线数据利用Othmer-Tobias方程,Bancroft方程,二元参数方程和Setschenow-type方程关联,通过关联得到的各参数数值可知:实验所得数据均很好地满足了各经验方程。证明了两种盐与离子液体[EPy]Br形成双水相的可能性,为进一步从理论和实践上分析及应用该离子液体双水相体系奠定了基础。

The liquid-liquid equilibrium （LLE） data and tie-line data have been investigated experimentally for N- ethyl-pyridinium bromide （ [ EPy] Br） ＋ potassium sodium tartrate （ C406 H4KNa）/dipotassium hydrogen phosphate （K2 HPO4 ） ＋ water aqueous two-phase systems （ATPSs） at T = 298.15 K. Furthermore, the effective excluded vol- ume （EEV） values obtained from the binodal models for the two systems were determined, and the salting-out abil- ity of K2HPO4 was found to be higher than that of C406H4KNa. The binodal data were correlated by the Merchuk and other equations, while the tie-line data were correlated by Othmer-Tobias, Bancroft, two-parameter and Setschenow-type equations. The results obtained using these equations were in fair agreement with the experimental data. Both potassium sodium tartrate and dipotassium hydrogen phosphate were shown to form an ATPS with N-eth- yl-pyridinium bromide, laying a good foundation for further theoretical and practical studies of this kind of ATPS.