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。
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（[C_4MIm]NTf_2）,liquid-liquid extraction system B15C5-[C_4MIm]NTf_2/LiA（anions were bis（trifluoromethylsulfonyl）imide（NTf-2）,trifluoromethanesulfonate（OTf^-）and Cl^-）-H_2O 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[Li_4（B_（15）C_5）_4（OH）_2（H_2O）]（NTf_2）_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.
出处
《核化学与放射化学》
CAS
CSCD
北大核心
2017年第2期151-157,共7页
Journal of Nuclear and Radiochemistry
