MBr(M=Na,K)在离子液体[Bmim]Br水溶液中的溶解度

为探索溴化1-丁基-3-甲基咪唑(Bmim]Br)离子液体对无机溴化物MBr(M=Na,K)在水中溶解度的影响,采用等温溶解平衡法在常压下测定了298.15~328.15 K范围内MBr在Bmim]Br(1)+H₂O(2)溶液中的溶解度,考察了离子液体含量对溶解度的影响。实验结果表明,Bmim]Br的加入会显著降低MBr(M=Na,K)在水中的溶解度,离子液体Bmim]Br对KBr的盐析作用比对NaBr的盐析作用大。不同温度下的溶解度数据可用Pitzer混合电解质溶液模型进行关联,得到了混合离子相互作用参数以及MBr在混合溶剂中的平均活度因子和溶剂的渗透系数。模型计算的溶解度与实验结果吻合良好,平均活度因子和溶剂的渗透系数均随离子液体含量的增加而增加。

Solubilities of MBr(M=Na,K)in aqueous systems containing ionic liquid [Bmim]Br

In order to understand the effect of ionic liquid 1-butyl-3-methylimidazolium bromides(Bmim]Br)on the solubility of bromides MBr(M=Na,K)in aqueous solutions,isothermal solubilities of MBr inBmim]Br(1)+H₂O(2)systems were measured in a temperature range of 298.15 K to 328.15 K at atmospheric pressure.It was found that the addition of Bmim]Br triggered a remarkable decrease of salt solubilities in aqueous solutions.The results also showed thatBmim]Br had more evident salting-out effect on KBr than NaBr.The solubility data were correlated and calculated with the Pitzer model.The interaction parameters of the mixed electrolyte solutions,the average activity coefficients of MBr in mixed solutions,and the osmotic coefficients of solvent were obtained by using experimental results.The Pitzer model gave a satisfactory prediction for the solubilities of KBr and NaBr in aqueous systems containing ionic liquid Bmim]Br.Both the average activity coefficients of MBr in mixed solutions,and the osmotic coefficients of solvent increased with increasing ionic liquid concentration.