【摘要】 以高同位素效应的苯并-15-冠-5(简写为B15C5)为萃取剂,绿色稳定的1-丁基-3-甲基咪唑双(三氟甲烷磺酰)亚胺盐(简写为[C4MIm]NTf2)离子液体为溶剂,建立了B15C5-[C4MIm]NTf2/LiA(阴离子分别为双三氟甲基磺酸亚胺根NTf-2、三氟甲磺酸根OTf~-和Cl~-)-H2O液液萃取体系以高效分离锂同位素。重点考察了体系平衡时间及冠醚浓度、锂盐浓度、温度和pH对分配比D的影响,结果表明:体系萃取平衡较快,t≤30s;提高B15C5浓度和适当降低锂盐浓度有利于分配比D的提高,同等条件下分配比大小为LiNTf2>LiOTf>LiCl,均远高于其他萃取体系;温度和pH对分配比无显著影响。此外,对络合物晶体的研究发现锂盐与B15C5均形成1∶1络合物[Li4(B15C5)4(OH)2(H2O)](NTf2)2,离子液体体系中Li+可能多数以阳离子交换方式萃入有机相。更多还原

【Abstract】 By using high isotope effect extracting agent benzo-15-crown-5（B15C5）and green and stable solvent—ionic liquid 1-butyl-3-methylimidazolium bis（trifluoromethylsulfonyl）imide（[C₄MIm]NTf₂）,liquid-liquid extraction system B15C5-[C₄MIm]NTf₂/LiA（anions were bis（trifluoromethylsulfonyl）imide（NTf-2）,trifluoromethanesulfonate（OTf-）and Cl-）-H₂O was established to separate lithium isotopes efficiently.Equilibrium time,effect of concentration of B15C5 and lithium salts,temperature and pH on distribution coefficient（D）were examined.The results indicate:the extraction equilibrium are short,t≤30s;increasing the concentration of B15C5 and reducing the concentration of lithium salts are conducive to improve the distribution coefficient（D）.Under the same conditions,the order of the Dis LiNTf2>LiOTf>LiCl,much higher than other extraction system;temperature and pH have no significant effect on the distribution coefficient.In addition,single crystal structure analysis of the complexes shows that all lithium salts are formed the same 1∶1complex as[Li₄(B₁₅C₅)₄（OH）₂（H₂O）]（NTf₂）₂with B15C5,indicating that Li+is most likelyextracted into organic phase by cation exchange process in ionic liquid system.The extraction system is efficient,green and has large capacity of lithium,it may have a high application value in industrial production.更多还原