Study On The Extraction Of Lanthanides By Tetrabutyldiamides

Based on the advances of the new extractants for actinides, the new extractants N,N,N,N-tetra-Butylsuccinylamide (TBSA), N,N,N,N-tetrabtylgutramide (TBGA) were synthesized, and the new method to prepare N,N,N',N'-tetrabutylmalonamide(TBMA) was given. The purity of the extractants was checked by IR spectra. The extraction of trivalent by lanthanides with TBMA, TBSA, TBGA from nitric acid media were investigated in detai 1. The following results had been obtained:1. The extraction rule of mechanisms of lanthanides with TBMA in toluene: the extraction efficiency of lanthanides increase firstly and then decrease with the increase in the atomic number, i.e. with the increase in the number of 4f electronics.2. In the nitric acid media, it is propitious to the extraction at low acidity and the TBMA extractability descends with the decrease in acidity.3. Salting-out effect on the extraction equilibrium is notable. The distribution ratio of lanthanides with three diamidese emploied increase with the enhencement of the salting-out agent concentration. The salting-out effect of LiNO3 is bigger than that of NaNO3 and4. The stoichiometries of extracted species are M(NO3)3 ·3TBMA, M(NO3)3 ·3TBSA and M(NO3)3 · 3TBGA respectively.5. The order of the extractability of TBMA for Samalium(III) in different diluents is as follows, benzene, cyclohexane>toluene>xylene>benzene>tetrachloromethane>chloroform. The diluent do not affect the stoichiometry of the extacted complex.6. The extraction distributions ratio decrease with the increase in the temperature ,which shows that the extraction reaction of lanthanides with the tetrabutyldiamides is exothermic, and the the increase in the temperature go agaist extraction.7. the characterization of the extacted complex shows that M3+ is eight -coordinated, whose coordinated configuration is similar to that in aqueous solution. The NO3- is bidentate in the complex.8. The comparison of the extractant's structure with the extracbility shows: the extractbility of TBSA is similar to TBGA and that of TBMA is best, which can be interpreted with the stability of the of the chelated extracted species.