高放废液中分离回收镧系-锕系元素萃取剂的研究进展

概述了近十几年来国内外有关用于高放废液镧系-锕系元素萃取分离中新萃取剂的研究进展,并对酰胺类、硫代磷类、硫代吡唑啉酮类等新萃取剂的设计筛选等进行了讨论。     

酰胺类萃取剂萃取分离铕的研究进展

酰胺类萃取剂容易合成,热稳定性好,能完全燃烧,对环境友好等一系列优点,已广泛的用来从核燃料的后循环中萃取分离镧系元素和锕系元素。论述了使用不同类型的酰胺类萃取剂萃取及其分离铕的研究,重点讨论了丙二酰胺类和丁二酰胺萃取剂、酰胺莢醚类萃取剂、吡啶二甲酰胺类萃取剂、乙酰胺基胺类萃取剂萃取分离铕的最新研究成果,同时对这几类催化剂萃取铕的萃取效果进行了比较和讨论。     

N,N,N'''',N''''-四丁基戊二酰胺萃取镧系元素研究

双酰胺萃取剂具有螯合性能，能从硝酸介质中萃取各价态锕系元素。其降解产物对萃取过程影响很小，能够燃尽，易于处理，合成也较容易，因此被认为是在高放废液的分离-嬗变工艺以及稀土湿法冶金等方面很有前途的一类萃取剂，IBGA萃取硝酸、铀(Ⅵ)和钚(Ⅳ)及其配合物结构研究已有报道，但关于从硝酸介质中萃取稀土元素的系统研究报道较少。我们对，IBGA萃取多种稀土元素的性能进行了详细考察，本文报道镧(Ⅲ)、镨(Ⅲ)、钆(Ⅲ)和铒(Ⅲ)的萃取研究结果。     

锕系元素分离研究:不对称双酰胺荚醚的萃取化学及应用

PUREX乏燃料后处理流程排放出的高放废液,集中了乏燃料中95%以上的放射性,其中半衰期长、毒性大的次锕系核素是需要在地质处置库中将高放废液与生物圈隔离10万年以上的因素之一。为了更安全可靠地解决高放废液问题,国际上提出了"分离-嬗变"技术,即利用化学方法,将次锕系元素和长寿命裂变产物元素从高放废液中分离出来,根据分离出来元素的性质,对其加以利用或使其嬗变。分离-嬗变技术中的关键是对高放废液中不同类别元素的有效分离。双酰胺荚醚类萃取剂对高放废液中三价锕系、镧系元素展现出了优异的萃取性能,尤其是不对称双酰胺荚醚,在保持相应的对称性双酰胺荚醚良好的萃取性能的同时,在缓解或避免萃取过程中第三相形成方面也有较大优势。本文就不对称酰胺荚醚的历史沿革、合成方法、萃取性能、配位机理、流程工艺以及三相形成等几个方面进行了综述,就多种不对称双酰胺荚醚萃取剂对锕系、镧系及其他主要裂片元素的萃取分配比、分离系数、三相形成临界参数等进行了比较,对该类萃取剂后续的结构设计、配位机理研究及流程应用等方向提供了参考性建议。     

N,N''-二甲基-N,N''-二辛基丙二酰胺萃取铀(Ⅵ)的研究

双酰胺萃取剂由于具有螯合性能,能从硝酸介质中萃取三价、四价、六价锕系元素,从而引起研究者的广泛兴趣[1～3].其降解产物对萃取过程影响很小,能够燃尽,易于处理,合成也较容易,因此在核燃料后处理方面展示较好的应用前景.     

N，N′-二甲基-N，N′-二辛基-3-氧戊二酰胺从盐酸介质中萃取三价镧系金属的研究

以煤油/辛醇(7:3,V/V)为稀释剂,研究N,N′-二甲基-N,N′-二辛基-3-氧戊二酰胺(DMDODGA)从盐酸介质中萃取三价镧系金属的性能及反应机理;考察了水相盐酸浓度、萃取剂浓度及温度对其萃取性能的影响。结果表明分配比在所研究酸度范围内随盐酸浓度的增加先增大后减小;随萃取剂浓度的增加而增大;萃合物的组成为MCl3.2DMDODGA(M=Sm,Gd,Dy)或MCl3.DMDODGA(M=Er,Lu)。萃取过程为放热反应,升高温度不利于萃取。同时计算出了萃取反应的平衡常数及热力学函数。萃合物的红外光谱表明羰基氧、醚氧均与镧系离子配位。     

N,N,N‘,N’—四己基丙二酰胺从硝酸介质中萃取铀（Ⅵ）

以甲苯为稀释剂研究了N，N，N'，N'－四己基两二酰胺从硝酸介质中萃取硝酸和铀（Ⅵ）的性能．考察了水相硝酸浓度、李取剂浓度、硝酸钠浓度以及温度对萃取分配比的影响，确定了萃合物的组成．借助红外光谱分析了萃合物的结构．求得了萃取硝酸和硝酸铀酰的平衡常数及反应的热力学焓变．与N，N，N'，N'－四丁基丙二酰胺萃取铀的性能比较，发现烷基链长的增加减少了三相生成的倾向，但酰胺的萃取能力却下降．     

N,N-二烷基酰胺萃取硝酸的性能

酰胺萃取剂的羰基氧具有很强的碱性,易萃取酸.考虑到酰胺萃取酸后对其萃取金属离子的性能有影响,研究酰胺对硝酸的萃取是必要的.     

N,N,N'',N''-四丁基丙二酰胺萃取镧系元素的性能及机理

研究新型萃取剂从硝酸盐介质中萃取分离稀土元素对于后处理工艺具有重要意义.本文报道以甲苯为稀释剂,N,N,N',N'-四丁基丙二酰胺(TBMA)从硝酸盐介质中萃取铈(Ⅲ)、镝(Ⅲ)、铒(Ⅲ)、镨(Ⅲ)、钐(Ⅲ)、铽(Ⅲ)、铥(Ⅲ)、镱(Ⅲ)的机理.考察了硝酸浓度、TBMA浓度、盐析剂浓度以及温度对上述三价镧系离子分配比的影响.得出萃合物的组成主要是三配体配合物M(NO3)3·3TBMA;计算出萃取反应的条件平衡常数、萃取平衡常数.温度效应研究表明萃取反应主要是焓驱动的.对萃取分离系数以及TBMA萃取三价镧系离子的规律进行了初步研究.     

三硝酸根二(N，N，N′，N′-四丁基丙二酰胺)合镨(Ⅲ)配合物的晶体结构及热分解性质

双酰胺萃取剂由于具有螯合性能,能从硝酸介质中萃取三价、四价、六价锕系元素,从而引起研究者的广泛兴趣[1,2]。其降解产物对萃取过程影响很小,能够燃尽,易于处理,合成也较容易,因此在核燃料后处理及绿色萃取化学方面具有很好的发展前景。丙二酰胺类萃取剂原料易得、合成方法简单,因此其萃取锕系[3￣7]、镧系元素[8￣11]以及硝酸[12]等的性能及机理报道较多,但TBMA萃取镧系元素形成的萃合物的晶体结构未见文献报道。对此类配合物空间结构及配位构型的研究不仅有助于萃取机理的分析,同时将为新萃取剂的设计提供理论依据。另外,萃合物的红外…     

Extraction of palladium with acyclic analogs of thiacalix[4]arenes from nitric acid solutions

p-tert-Butylcalix[4]arene was compared with its acyclic analogs in palladium extraction from nitric acid solutions as mononuclear and poly(bi)nuclear complexes with participation of protonated molecules of podands and macrocycle. The extraction ability of podands is similar to that of macrocycle because of the same character of complexation (Pd: S = 1: 1) without formation of new chelates and lower than that of monodentate analog owing to formation of a square complex (Pd: S = 1: 2).     

alpha-Keto amides as precursors to heterocycles--generation and cycloaddition reactions of piperazin-5-one nitrones

alpha-Keto amides 10a,b, formed from reaction of pyruvic or benzoylformic acid with allyl amine are found to present as single rotameric forms whilst their tertiary amido analogues 10c, d present as two rotamers in solution at rt. The hydroxyimino derivatives 8 share the conformational characteristics of their parents. The geometrical make-up of the new alpha-amidooximes is seen to depend on the structure of the starting acid and on the degree of substitution of the amido group. The oxime 8a derived from pyruvic acid and allyl amine is formed solely as the (E)-isomer whilst its tertiary amido analogue 8c is formed as both (E)- and (Z)-isomers. Oximes derived from benzoylformic acid have the opposite selectivity with both geometrical isomers forming from the secondary amide 8b and only the (Z)-isomer from the tertiary amide 8d. With the exception of 8b all oximes were configurationally stable with (Z)-isomers reacting to form isoxazolopyrrolidinones 11--compounds with a relatively rare bicyclic nucleus and (E)-isomers cyclising to piperazin-5-one nitrones 1--ketopiperazine N-oxides have to date only appeared once in the literature. New nitrones were trapped with phenyl vinyl sulfone, dimethyl acetylenedicarboxylate and methyl propiolate yielding isoxazolidine and isoxazoline fused piperazinones 13, 15, 21 and 22. Cycloadducts from dimethyl acetylenedicarboxylate and 8a, b are thermally labile and their rearrangement provides a novel route to pyrrolopiperazinones 16. The structure of a representative isoxazolopyrrolidinone, 11c, and a 2,3-dihydroisoxazoline fused piperazinone, 21b, are unambiguously solved following x-ray structural analysis.     

Design of Extractants for F-Block Elements in a Series of (2-(Diphenylphosphoryl)methoxyphenyl)diphenylphosphine Oxide Derivatives: Synthesis,Quantum-Chemical,and Extraction Studies

With the aim to find new efficient extractants for recovery of f-block elements from processing wastes of different origin, we have compared a series of phosphoryl-containing podands, including (2-(diphenylphosphorylmethoxy)phenyl)diphenylphosphine oxide 1 and its analogues 5–7, where the ArP(O)Ph₂ group of phosphine oxide type is replaced by phosphonic fragments. Quantum-chemical modelling of the structures of phosphoryl-containing podands 1 and 5–7 has been performed, which was later confirmed by the data of X-ray diffraction. The features of extraction of nitric acid, as well as U(VI), Th(IV), Nd(III), and Ho(III) with compounds 1 and 5–7 from nitric acid media into 1,2-dichloroethane have been studied. The compositions of extracted complexes have been determined.     

Aliphatic Hyperbranched Poly（amido amine）s （PAMAMs） ： Preparation and Modification

A series of water soluble aliphatic hyperbranched poly(amido amine)s(PAMAMs) with the same or similar chemical structure of poly(amido amine) dendrimer was successfully synthesized from commercially available AB and Cn types of monomers by one-pot polymerization via the couple-monomer methodology(CMM). The AB type monomer used in this paper was methyl acrylate, and Cn monomers were multi-amino compounds such as ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetraamine (TETA). tetraethylenepentaamine (TEPA) and pentaethylenehexamine (PEHA). The reaction mechanism was investigated by means of the mass spectra of the reaction intermediates. Adjusting the feed ratio of AB to Cn. hyperbranched polymers with different terminal groups and properties were obtained. FTIR, NMR, DSC. and TGA were used to characterize the polymers. It was found that the polymers‘ properties such as solubility, thermal behaviour and encapsulation capability varied with changing the feed ratio of AB to Cn. Benzoyl and palmitoyl groups were introduced into these macromolecules by acidylation to form amphiphilic hyperbranched polymers which have a high capability to encapsulate water soluble dyes such as Congo red. It is expected that the hyperbranched PAMAMs can play an important role in the industrial applications, such as coatings, cross-linking and phase-transferring agents because of their versatility and availability.     

Synthesis and Ionophoric Properties of α,ω-Diphosphorylated Aza Podands: II. Kabachnik-Fields Reaction as a Method for Design of α,ω-Diphosphorylated Aza Podands and Their Use for Determination of Metal Ions

Methods of the design of podands with α-aminomethylphosphine oxide terminal groups with the purpose of investigation of the ionophoric properties of the podands and their use as components of ion-selective electrodes are analyzed. The most convenient procedure is a one-pot synthesis based on the Kabachnik-Fields reaction in a system comprising a dialkyl(aryl)phosphinous acid, formaldehyde, and a diamine. An alternative procedure is two-stage and involves the reaction of a primary amine with a phosphinous acid and formaldehyde to form an α-aminomethyldialkyl(aryl)phosphine oxide in the first stage and cross-linking of two molecules of this compound via reaction with a dihalooligoether of the corresponding length in the second. Advantages and disadvantages of both procedures are considered. Electrode-active properties of the prepared aza podands are studied to show that ion-selective electrodes on their basis can be used for selective determination of low concentrations of alkali and alkaline-earth metal ions.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 2, 2005, pp. 244–252.Original Russian Text Copyright © 2005 by Garifzyanov, Vasil’ev, Cherkasov.For communication I, see [1].     

Relation between the structure and extracting power of higher tertiary amines

The effect of the composition and structure of higher tertiary amines on their efficiency in extracting nitric acid has been examined. The ionization constants of the amines in methanol have been determined by potentiometric titration. The extraction constants for nitric acid have been determined at constant ionic strength in the aqueous phase (μ=1). The dependence of these constants upon the concentrations and the degree of association of the amine salts in the organic phase has been examined. For the cases in which the role of steric factors is negligible it has been shown that at low amine salt concentrations in the organic phase there are quantitative regularities between the ionization constants of the amines in methanol, their extraction constants for nitric acid and the inductive effects of the substituents on the nitrogen atom.     

Effect of diluents in U(VI) extraction with N,N'-dihexanoylpiperazine

A systematic investigation has been carried out on the extractive behavior of N,N'-dihexanoylpiperazine (DHPEZ) with respect to U(VI) in five diluents, from aqueous nitric acid media. The variation of U(VI) distribution ratio with the concentrations of aqueous nitric acid, extractant, salting-out agent and with temperature has been investigated and discussed. The increasing order of extractive ability of DHPEZ towards U(VI) is: chloroform, carbon tetrachloride, 1,4-dimethyl-benzene, toluene, benzene. The composition of the extracted species and extraction constants as well as the enthalpy changes are given.     

Aggregation states and molecular motion of polymer ultrathin films prepared at the air/water interface

Surface structure and dynamics in three different polymeric ultrathin systems, such as organosilane monolayers, poly(methyl methacrylate) (PMMA) brushes and poly(amido amine) dendrimer monolayers are discussed.     

新法合成酰胺荚醚萃取剂

采用混合酸酐法,通过氧杂单酰胺酸与二烷基胺反应,合成了3种酰胺荚醚萃取剂N,N,N'N'-四烷基-3-氧-戊二酰胺(烷基为正丁基、异丁基和正辛基),产率分别为84%,80%和57%.采用1H NMR和MS对合成的酰胺荚醚萃取剂的结构进行了表征.     

Novel Tailored Polymeric Surfactant for Dispersing Clay into the Non Polar Polymer

Polymers have entropy nearly zero which cause mixing of different polymers or with the fillers become very difficult. There is generally a third component necessary which is called surfactant to enhance the miscibility. The surfactant reduces interfacial tension and improves the interfacial adhesion. In this work, tailored polymeric surfactant is designed and utilized for dispersing the clay in nano scale in to the polymer matrix Polypropylene (PP). These were prepared directly from Na⁺ Bentonite by reactive processing in which melt intercalation technique was carried. They are Polypropylene-g-acrylic amido Poly(oxypropylene) ammonium chloride (POPA). This ammonium salt was prepared from diamine and Polypropylene-g-acrylic acid by the formation of amido amine and sequentially neutralized it with the hydrochloric acid solution. The amido amine formation was verified by the FTIR technique. Clay loading was kept at 5 weight % by this new technique. Their structures were characterized by x-ray diffraction (XRD). The distribution of clay in the matrix was also studied through optical microscope (OM) and scanning electron microscope (SEM). These techniques revealed that the polymeric surfactant enhances the dispersion and the dispersed clay is hardly found in the SEM images.