吡啶吡唑基配体C8-BPP对硝酸溶液中Am^(3+)和Eu^(3+)的萃取

Extraction of Am(Ⅲ) and Eu(Ⅲ) from Nitric Acid Solution with the Pyridylpyrazole Based Ligand C8-BPP

合成了吡啶吡唑基配体C8-BPP[2,6-bis(5-(n-octyl)-1H-pyrazol-3-yl)pyridine],并采用红外光谱、核磁共振波谱、质谱等手段对其进行了表征.以正十二烷为稀释剂,2-溴己酸为协萃剂,研究了C8-BPP从HNO3溶液中萃取Am^(3+)和Eu^(3+)的行为.重点考察了萃取时间、酸度和萃取剂浓度等对分配比D和分离因子SF_(Am/Eu)的影响.在HNO3浓度为0.2~1.0 mol/L时,C8-BPP萃取Am^(3+)和Eu^(3+)的D值随HNO3浓度增加而减小,SF_(Am/Eu)值先增大后减小;HNO3浓度为0.5 mol/L时,SF_(Am/Eu)达到55.随着配体浓度的增加,C8-BPP萃取Am^(3+)和Eu^(3+)的D值均增加,SF_(Am/Eu)值缓慢减小,但仍在40以上.斜率分析表明,C8-BPP萃取Am^(3+)和Eu^(3+)均形成了1∶1型的萃合物.还采用紫外滴定、高分辨质谱、红外光谱、拉曼光谱和时间分辨荧光光谱等方法研究了C8-BPP与Eu^(3+)的配位化学行为,并得到了配合物的组成和稳定常数.

Pyridylpyrazole based ligand 2,6-bis [ 5- （n-octyl） - 1H-pyrazol-3-yl ] pyridine （ C8-BPP ） was syn- thesized and characterized by means of mass spectrometry （MS）, nuclear magnetic resonance （NMR） spec- trometry, and Fourier transform infrared spectrometry （FTIR）. In the presence of 2-bromohexanoie acid, using n-dodecane as diluent, the extraction behaviors of Am^3＋ and Eu^3＋ with C8-BPP were investigated. Influences of diluent, contact time, acidity and the ligand concentration on the extraction of Am^3＋ and Eu^3＋ were evaluated in HNO3 solution. The distribution ratio values of Am^3＋ and Eu^3＋ decreased with increasing HNO3 concentration from 0. 2 to 1.0 mol/L, and increased with increasing ligand concentration from 0.01 to 0. 1 mol/L. With the increase of acidity, the separation factors （SFAm/Eu） increased firstly and then decreased. The maximum value of SFAm/Eu can reach 55 at 0. 5 mol/L HNO3. Meanwhile, SFAm/Eu values decreased slowly with increasing the ligand concentration but all the SFAm/Eu values were above 40. The extraction results also showed that C8-BPP exhibited good selective extraction ability for Am^3＋ over RE^3＋. Moreover, slope analyses indicated the formation of 1 ： 1 complexes of C8-BPP with Am^3＋ and Eu^3＋, separately. Besides, the complexation behaviors of C8-BPP with Eu^3＋ were also investigated by means of UV-Vis spectrometry titration, electrospray ionization mass spectrometry（ ESI-MS ）, FTIR, Raman spectrometry and time-resolved laser-induced fluorescence spectroscopy （TRLFS）. The composition and stability constant（lgK） of the complex of C8-BPP with Eu^3＋ were also obtained.