助手标题  
全文文献 工具书 数字 学术定义 翻译助手 学术趋势 更多
查询帮助
意见反馈
   lanthanide extraction 的翻译结果: 查询用时:0.192秒
图标索引 在分类学科中查询
所有学科
更多类别查询

图标索引 历史查询
 

lanthanide extraction
相关语句
  镧系元素萃取
     PACKING DIAGRAM——APPLICATION OF PACKING MODEL IN LANTHANIDE EXTRACTION
     堆积图——堆积模型在镧系元素萃取中的应用
短句来源
  “lanthanide extraction”译为未确定词的双语例句
     STUDIES ON THE SYNTHESIS OF OCTYL PHOSPHONIC ACID MONOOCTYL ESTERS AND THEIR STRUCTURE-REACTIVITY RELATIONSHIP IN LANTHANIDE EXTRACTION
     辛基膦酸单辛酯的合成及其萃取镧系元素的结构-性能研究
短句来源
  相似匹配句对
     PACKING DIAGRAM——APPLICATION OF PACKING MODEL IN LANTHANIDE EXTRACTION
     堆积图——堆积模型在镧系元素萃取中的应用
短句来源
     Extraction equilibria of mono and binary systems of lanthanide with PMBP
     镧系元素一元和二元体系与PMBP的萃取平衡
短句来源
     Extraction of Pection
     果胶的提取
短句来源
     Extraction of the Nicoline
     烟碱的提取
短句来源
     MAGNETOCHEMISTRY OF LANTHANIDE COMPOUNDS
     镧系化合物的磁化学
短句来源
查询“lanthanide extraction”译词为用户自定义的双语例句

    我想查看译文中含有:的双语例句
例句
为了更好的帮助您理解掌握查询词或其译词在地道英语中的实际用法,我们为您准备了出自英文原文的大量英语例句,供您参考。
  lanthanide extraction
dm-3) and, among the cations, Zn(II) Cu(II), Co(II) and Fe(III) reduced the lanthanide extraction.
      
Actinide and lanthanide extraction from nitric acid solutions by flotation
      
Semi-empirical relations were derived describing lanthanide extraction in lanthanide macro- and microconcentrations as a function of the extraction of lanthanide macroconcentrations.
      
The effect of macroconcentration (Ma) lanthanide extraction on the microcomponent (Mi) extraction by D2EHPA was investigated.
      
Solvation effects in the second organic phase in lanthanide extraction by benzyldialkylamines have been investigated by means of chemical analysis of the second organic phase, liquid chromatography, osmometric data and logarithmic analysis.
      
更多          


Solvent extraction of metal ions may be regarded as a multicomponental coordinative chemical reaction between two immiscible phases. This thermodynamic process is evidently influenced by the spatial configuration of both ligand and metal ion to be extracted. The steric feature consisting of shielding, conformational and spatial effects are, however, determined by the composition, structure and configuration of the coordination compounds. Steric effects play an important role in the investigation of organic extractants...

Solvent extraction of metal ions may be regarded as a multicomponental coordinative chemical reaction between two immiscible phases. This thermodynamic process is evidently influenced by the spatial configuration of both ligand and metal ion to be extracted. The steric feature consisting of shielding, conformational and spatial effects are, however, determined by the composition, structure and configuration of the coordination compounds. Steric effects play an important role in the investigation of organic extractants with high selectivity. In the mathematical model of the molecular design of extractants, the steric constant is one of the most important terms.The great similarities in chemical and physical properties of rare earths tend to the difficulties in their separation. The present paper describes the successful trial on extractive separation of these elements based on the steric effects of ligands which is enhanced by lanthanide contraction.As shown by our early studies[4] that the spatial configuration of the ester alkyl group in the molecule of dialkyl methylphosphonates has a remarkable effect on the extraction of uranium and thorium. These significant differences were contributed to the steric effect of ligands in the various composition of the extracted species. It is reasonable to predict that similar structural condition exist in the lanthanide extraction as in thorium extraction due to the similar atomic radius and identical composition of the extracted coordination compounds. An evident steric effect of ester alkyl group of both dialkyl phenylphosphonates and dibutyl alkylphosphonates was observed in extraction of cerium, promethium and yttrium. The extraction behaviour of lanthanum, praseodymium, neodymium, samarium and ytterium by dialkyl isopropylphosphonates was influenced in a certain extent by the spatial configuration of the ester alkyl group. The dependence of structural feature of these organophosphorus ligands on the thermodynamic functions △H, △Z and T△S of the extraction reaction are discussed.The structure-reactivity studies of various types of acidic organophosphorus compounds in extraction of light, medium and heavy rare earths as neodymium, samarium, ytterbium and ytterium as representatires demonstrated that both di(2-ethylhexyl)phosphinic acid and di-n-octylphosphinic acids are isomeric compounds with almost the same pKa values, but the difference in their K_(ex) for Nd, Sin, Y and Yb extraction is of four orders of magnitude. This is attributed to the apparent steric hindrance arising from two branched alkyl radical directly linked to the coordinating group. In the former molecule, there are two octyl groups with substituent on the β-position, which inhibit the coordination of the extractants with metal ions. The steric effect in extraction of rare earths was weakened with the increasing in atomic number while the atomic radius was decreased due to the lanthanide contration. Similar structural effects have been found in the extraction of rare earths by dioctyl aralkylphosphonates. The steric effect or acidic organophosphorus ligands on lanthanide extraction is well demonstrated by the fact that the lgK_(ex) and the △S calculated in the extraction reaction of rare earths by 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester increase with the increase of the atomic number and reveals the "tetrad effect".On the basis of experimental data the steric constants of various alkyl and alkyloxyl groups in mono-basic acidic phosphorus ester in extraction of rare earths was estimated.

金属的溶剂萃取是两相间多组成的配位化学反应,配位体及被萃离子的空间结构对这个热力学过程有显著影响,它与形成热力学稳定的配位化合物有关。包括屏蔽效应,构象效应和空间张力在内的结构空间效应不仅决定于配位体及金属离子的结构,同时也与所形成的萃合物的结构和构型直接相联系,它是萃取剂分子设计数学模型中的重要结构参数。 稀土配位化合物一般为八面体构型,结构空间效应的影响不显著,但镧系收缩特性,为应用配位体的结构空间效应提供了可能性。 本文着重讨论了中性磷(膦)酸酯及酸性磷(膦)酸酯萃取稀土反应中的结构空间效应对萃取性能的不同影响,以及与反应的熵变值及萃合物结构的联系,同时对萃取稀土反应中有机取代基团Es值的测定作了探讨。

Acidic phosphorus compounds are a type of extractant with powerful extractability for lanthanides, in which alkyl phosphonicacid monoalkyl ester possesses the most excellent separation behaviour. In order to develop a new high efficient extractant, it is meaningful to examine the effect of the alkyl structure in the molecule of alkyl phosphonic acid monoalkyl ester on the separation ability of lanthanides.Nine octyl phosphonic acid monooctyl esters with various alkyl groups have been synthesized for the structure-reactivity...

Acidic phosphorus compounds are a type of extractant with powerful extractability for lanthanides, in which alkyl phosphonicacid monoalkyl ester possesses the most excellent separation behaviour. In order to develop a new high efficient extractant, it is meaningful to examine the effect of the alkyl structure in the molecule of alkyl phosphonic acid monoalkyl ester on the separation ability of lanthanides.Nine octyl phosphonic acid monooctyl esters with various alkyl groups have been synthesized for the structure-reactivity study on lanthanide extraction in this paper. The required extractant with>99% of purity were synthesized using the follwing procedure: the reaction of ethanolamine with dioctyloctylphosphonate which was prepared by P-alkylating of dioctyl phosphite and followed by purification of the crude products by crystallization of its copper salt.The distribution ratios of lanthanum, europium and lutecium between dodecane solution of studied extractant and aqueous solution with constant ionic strength (1.0M) and various acidity in nitrate media were determined. By extrapolation the regressive values of distribution ratios were obtained for the purpose of structure-reactivity study at the identical condition.By examining the obtained values as shown in Table 2, the following order in extraction ability of La. Eu and Lu was observed: Ⅰa>Ⅰb>Ⅲa>Ⅱa>Ⅰc>Ⅱb>Ⅲb>Ⅱc>Ⅲc.The extractants Ⅰa with the alkyls as n-octyl and Ⅲc with the alkyls as sec-octyl possess the strongest and weakest extractability among these acidic phosphonates. The first five extractants in the series all have one straight chain alkyl, n-octyl at least in their molecule. It is evidently shown that the lanthanide extraction by octyl phosphonic acid monooctyl esters decreases with the strengthening of isomerization of the alkyl group as the steric hinderance towards phosphorus atom is enhanced.The steric effect also has the obvious influence on the separation behaviour of octyl phosphonicacid monooctyl esters in lanthanide extraction. For light lanthanides (La-Eu), the acidic phosphonates with less steric effect of straight chain group n-octyl demonstrate smaller separation behaviour. With proper degree of isomerization in alkyl group, both 2-ethylhexyl phosphonicacid mono-2-ethylhexyl ester (Ⅱb) and n-octyl phosphonicacid mono-1-methylheptyl ester (Ⅰc) posses excellent average separation factor 3.04 and 2.89 respectively for whole lanthanide series.In addition, synergetic effect does not appear with the mixture of these acidic phosphonates in lanthanide extraction.

合成了九个不同辛基结构的辛基膦酸单辛酯,测定了它们的正十二烷溶液在恒定离子强度和不同酸度的硝酸介质中萃取镧、铕和铅的分配比,并以外推法得到了归一化的分配比数值,从而进行了萃取剂结构与性能关系的研究。考察了辛基膦酸单辛酯的烷基支链化程度时萃取镧系元素的能力和分离性能的影响:随着邻近配位基团的烷基支链化程度的增加,其萃取能力下降;但一定的支链对萃取剂分子是必需的,如2-乙基已基膦酸单2-乙基己基酯和正辛基膦酸单1-甲基庚基酯皆具有最佳的分离性能。从空间效应解释了所得的结果。

The structure and reactivity studies on the extraction of lanthanides by six dialkyl alkoxycarbonylmethanephosphonates with various alkyl groups are described. The steric effect shows obvious influence on the behaviour of dialkyl alkoxycarbonylmethanephosphonate in the lanthanide extraction. There are two peaks in the extraction curve of lanthanide. The extraction increases with the increasing of atomic number from La to Eu, but decreases at Gd, and increases again with the atomic number...

The structure and reactivity studies on the extraction of lanthanides by six dialkyl alkoxycarbonylmethanephosphonates with various alkyl groups are described. The steric effect shows obvious influence on the behaviour of dialkyl alkoxycarbonylmethanephosphonate in the lanthanide extraction. There are two peaks in the extraction curve of lanthanide. The extraction increases with the increasing of atomic number from La to Eu, but decreases at Gd, and increases again with the atomic number thereafter. There is another peak at Dy. The extraction mechanism studied by slope method is similar to that for normal neutral solvent complex extraction. The composition of the extracted coordination compound is Ln:L=1:3, where Ln=La, Dy, Lu and L=(R,O)_2—CH_2—OR_2.The elemental analysis and molecular weight determination of the coordination compound formed by La(NO_3)_3 and (C_4H_9O)_2—CH_2—OC_3H_7(i) give the same conclusion. The IR absorption spectra of the dialkyl alkoxycarbonylmethanephosphonate complexes with the nitrate of lanthanide are investigated. We have shown that the P=O is the primary donor and the carbonyl group involves partly in the coordination.

报道了6个具有不同烷基结构的新型中性双配位有机磷萃取剂——二烷氧基膦酰乙酸酯(R_1O)_2PO-CH_2-CO-OR_2对镧系元素的萃取性能和规律。该类萃取剂中二个配位基团P=O和C=O附近的酯烷基R_1和R_2的结构变化明显地影响其对镧系元素的萃取能力,分配系数随着镧系元素原子序数的增大而呈双峰效应,萃取机理与一般中性溶剂化络合萃取相似。萃取配台物中镧系元素与配体的摩尔比为1:3,并用元素分析、分子量测定和红外光谱对二丁氧基膦酰乙酸异丙酯与硝酸镧配合物进行了研究。

 
图标索引 相关查询

 


 
CNKI小工具
在英文学术搜索中查有关lanthanide extraction的内容
在知识搜索中查有关lanthanide extraction的内容
在数字搜索中查有关lanthanide extraction的内容
在概念知识元中查有关lanthanide extraction的内容
在学术趋势中查有关lanthanide extraction的内容
 
 

CNKI主页设CNKI翻译助手为主页 | 收藏CNKI翻译助手 | 广告服务 | 英文学术搜索
版权图标  2008 CNKI-中国知网
京ICP证040431号 互联网出版许可证 新出网证(京)字008号
北京市公安局海淀分局 备案号:110 1081725
版权图标 2008中国知网(cnki) 中国学术期刊(光盘版)电子杂志社