Extraction of lanthanide ions with N,N,N′,N′-tetrabutyl-3-oxadiglycolamide from nitric acid media

Extractability and extraction mechanism of lanthanide ions were investigated by using a new extractant,N,Nn,N′,N′-tetrabutyl-3-oxa-diglycolamide(TBDGA),in toluene from nitric acid media.The effects of HNO_3 and TBDGA concentrations,and temperature,on extraction of lanthanide ions were studied.Stoichiometrics of the main extracted species were HNO_3·TBDGA and M(NO_3)_3-3TBDGA(M = Er,Dy,Tb,Gd,La,Ce,Nd,Sm and Eu).The extracted species for metal ions were established to be ionic complex.In this complex,nitrate anion was not coordinated to the central ion.The extraction pattern increased gradually across the lanthanide ions series,showing enhanced affinity of TBDGA toward heavy lanthanide ions.Thermodynamic parameters were investigated for the exothermic extraction reaction.

Solvent extraction of nitric acid, uranium(VI) and thorium(IV) by N,N,N',N'-tetrahexylsuccinylamide

A new kind of diamide N,N,N’,N’-tetrahexylsuccinylamide（THSA） was synthesized, characterized and used for the extraction of HNO3, U（VI） and TI（IV） in a diluent composed of 0.5 volume fraction 1,2,4-trimethy benzene（TMB） and 0.5 volume fraction kerosene（OK）. Extraction distribution coefficients of U（VI） and TI（IV） as functions of aque- ous nitric acid concentration, extractant concentration, temperature and salting-out agent （LiNO3 ） have been studied, and it is found that THSA as an extractant is superior to TBP for extraction of U（VI） and TI（IV）. Back extraction was also studied. At low acidity, the main adduct of THSA and HNO3 is HNO3.THSA. THSA.（HNO3）2 and THSA.（HNO3）3 are also found at high acidity. The compositions of extracted species, apparent equilibrium constants and enthalpies of extraction reactions have also been calculated.

Synthesis of N,N'-dimethyl-N,N'-didecyl-3-oxa-diglycolamide for extraction of lanthanides

A novel extractant,N,N'-dimethyl-N,N'-didecyl-3-oxa-diglycolamide(DMDDDGA),was designed and synthesized for extraction of lanthanides in the nuclear fuel reprocessing.The extraction behaviors of Gd,Dy,Er and Ho from nitric acid solution were investigated using DMDDDGA in chloroform.The effects of nitric acid concentration,extractant concentration,and temperature on the extraction were investigated.The distribution ratio of lanthanides increases with concentrations of the extractant and nitric acid,but decreases with increasing temperature,which indicates that the extraction process is exothermic.FT-IR spectra indicated that the C=0 in DMDDDGA is coordinated with metal ion in the extracted species and the stoichiometries of lanthanides(Ⅲ)complex are Gd(NO_3)_3·3DMDDDGA,Dy(NO_3)_3·4DMDDDGA,Er(NO_3)_3·4DMDDDGA,and Ho(NO_3)_3·4DMDDDGA.

稀释剂对N,N-二丁基十二酰胺萃取硝酸平衡的影响

本文研究了新萃取剂Ｎ，Ｎ二丁基十二酰胺（ＤＢＤＯＡ）萃取硝酸的机理。考察了不同稀释剂如：二甲苯、甲苯、四氯化碳、正辛烷、苯、环己烷、氯仿等对萃取平衡的影响，分析了萃取有机相的红外光谱。得到在不同稀释剂中萃取反应均为：ＨＮＯ３＋ＤＢＤＯＡ（０）＝ＨＮＯ３·ＤＢＤＯＡ（０）利用不同的稀释剂参数与萃取平衡常数进行了关联，发现任一参数都难以定量描述稀释剂的影响。

盐酸介质中N,N'-二甲基-N,N'-二辛基-3-氧戊二酰胺萃取Cu^(2+)的研究

研究盐酸介质中N,N'-二甲基-N,N'-二辛基-3-氧戊二酰胺对Cu2+的萃取行为,考察了不同稀释剂、水相酸度、氯化钠浓度、萃取剂浓度和温度对萃取分配比的影响.结果表明:体系酸度、氯化钠浓度或萃取剂浓度任意一个增大,萃取分配比随之增大;温度升高时,萃取分配比下降,说明该萃取反应是放热反应.通过热力学研究,得到了萃合物的组成.

TBP从盐酸溶液中萃取锡的稀释剂效应

TBP从盐酸溶液中萃取Sn^(4+)时,其稀释剂的影响不仅与稀释剂的性质有关,而且与盐酸浓度,萃取剂浓度,初始水相中锡的浓度等有关。只有[HCl]<6mol/L,[TBP]<40%,[Sn^(4+)]_(in)<1.5g/L时,才能排除这些因素的影响,因为这时各种稀释剂对Sn^(4+)的分配比D_(Sn^(4+))随这些因素的变化趋势相一致。在TBP-SnCl_4-HCl体系中,对于非极性类稀释剂,若按D_(Sn^(4+))的大小来排列,则烷烃类(环己烷、正己烷、正庚烷)>芳烃类(苯)>卤代烃类(四氯化碳),且可用稀释剂的极化率与摩尔体积等因素来解释;对于极性类有接受电子基团的稀释剂,则硝基苯>1,2-二氯乙烷>氯苯>氯仿,可用稀释剂的偶极矩、介电常数、溶解度参数或粘度等物性参数来解释其规律。