中文摘要：

通过对1-丁基-3-甲基咪唑四氟硼酸盐（[bmim][PF4]）离子液体＋水体系相平衡及NaCl、NaBF4和氯化1-丁基-3-甲基咪唑（[bmim]Cl）对离子液体＋水体系相平衡的影响进行了研究，结果表明：离子液体[bmim][BF4]＋H2O二元体系具有典型的最高上临界溶解温度（UCST）行为，其最高上临界温度为5．3℃左右，临界组成为50％（水的质量分数）；NaCl和NaBF4降低[bmim][BF4]＋H2O体系的混溶性，而[bmim]Cl增加该体系的混溶性。由此得到一种简单定性地判断离子液体[bmim][BF4]中可能存在的杂质种类和水平的方法，并利用此结果可设计纯化该离子液体的绿色工艺。

英文摘要：

The phase equilibrium of 1-buthy-3-methylimidazolium tetrafluoroborate （[bmim][BF4]） ionic liquid ＋ H2O system and the effect of NaCl, NaBF4 and 1-buthy-3-methylimidazolium chloride （[bmim]Cl） on the phase equilibrium of [bmim][PF4] ＋ H2O system were studied. The results show that [bmim][BF4] ＋ H2O system has the upper critical solution temperature （UCST） type phase behavior; its upper critical solution temperature is about 5.3℃, and the corresponding critical composition of H2O is 50%（wt.）. It was found that NaCl and NaBF4 in [bmim][BF4] ＋ H2O system will decrease the miscibility of the system, while [bmim]Cl in the system will increase the miscibility of the system. According to these results, a simple and qualitative method of estimating the type and the level of the impurity in ionic liquid [bmim][BF4] was obtained, and the technological design of green purification of this ionic liquid can be carried out as well.