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1.
<正>钪作为稀土元素,具有独特的物理化学性质,如钪元素加到铝合金中,可以显著提高合金的再结晶温度,强烈抑制沿晶断裂倾向,提高合金强度、塑性和断裂韧性~([1-2])。近年来,随着新材料技术的迅猛发展,氧化钪(Sc_2O_3)更是广泛应用于固体氧化物燃料电池(SOFCs)~([3])、新一代激光晶体~([4])、大功率金属卤素灯、高能辐射用核能屏蔽、特种陶瓷等领域。但氧化钪中含有的杂质元素会导致这些材料性能极大下  相似文献   

2.
虞磊  吕宝源 《分析化学》2000,28(1):42-45
对电感耦合等离子体原子发射光谱(ICP-AES)法测定高纯三甲基镓(99.9999T,相对于金属镓的含量)中Cu、Fe、Si、Zn等31种痕量杂质元素的含量进行了研究,考察了基体元素镓对杂质元素的光谱和非光谱干扰以及基体浓度对杂质元素谱线信噪比和检出限的影响在优化的实验条件下,获得了满意的结果。  相似文献   

3.
石油亚砜萃取色谱法分离钪和稀土   总被引:1,自引:0,他引:1  
提出以石油亚砜为固定相,硫氰酸铵和盐酸为流动相的萃取色谱法分离钪和稀土。研究了影响钪和稀土分离的条件,本体系中钪和钕的分离系数达到1.3×10~4。该方法可用于混合稀土中小量钪的分离,提取和分析。  相似文献   

4.
采用P507选择性萃取分离赤泥酸浸液中的钪。研究了溶液pH值、P507用量、A/O和萃取时间对钪萃取率和分离效果的影响,同时分析了此体系中钪萃取热力学及钪和铁的萃取分离动力学特征。结果表明:当溶液pH值为0.6,P507用量为8%,A/O为15和震荡时间为6 min时,钪萃取率可达99%。铁离子是影响钪萃取和分离的主要杂质离子,随着震荡时间从2 min提高至10 min,D_(Sc)可由48提高到1650,而D_(Fe)仅提高至3.1,此时钪和铁均未达到平衡。当反应时间为6 min时,钪对铁的分离系数最大,β_(Sc/Fe)可达到776,此体系中钪的萃取焓变为20.46 kJ·mol(-1)。  相似文献   

5.
王子树  董兆权 《分析化学》1993,21(11):1323-1326
利用Sc^3+与SO^2-4形成络阴离子后强烈吸附在强碱性阴离子交换树脂上的性质,分离掉大部分基体钪后,留下一小部分钪作基体。定量加入内标,利用火花源介谱单曝光法测定杂质元素。  相似文献   

6.
高纯金属镱中杂质元素的电感耦合等离子体质谱法测定   总被引:5,自引:1,他引:4  
利用电感耦合等离子体质谱仪(ICP—MS)直接测定了金属镱中除Tm、Lu外其他稀土及非稀土杂质元素;通过P507萃淋树脂色层柱,分离绝大部分Yb基体,避免了基体元素对Tm、Lu的测定干扰?定量加入内标元素Sc、Cs,有效克服了基体效应所带来的偏差。稀土杂质元素的检出限0.010~0.032μg/g,非稀土杂质元素的检出限为0.12~5.0μg/g。加标回收率为83%~105%。方法适用于纯度为99.99%~99.999%的高纯金属镱产品中杂质元素的测定。  相似文献   

7.
电感耦合等离子体质谱法测定高纯金属铋中痕量杂质元素   总被引:8,自引:0,他引:8  
采用电感耦合等离子体质谱法测定了高纯金属铋中14种痕量杂质元素。考察了基体效应对测定元素的干扰影响,通过铋基体元素的分离和以Sc、In、Eu作为内标,有效克服了干扰现象。方法的检出限在0.1~4.7ng/mL;精密度在1.4%~5.0%;加标回收率在89%~114%范围。本法可满足99.999%以上金属铋中痕量杂质测定的要求。  相似文献   

8.
高纯铟及磷化铟中微量硅及金属杂质的测定方法很多。用比色法测定硅时,分离方法复杂,空白值较高。质谱法及中子活化法灵敏度很高,能同时测定多种杂质元素,但由于设备条件的限制,目前还不易普及推广。用普通的化学光谱法测定铟及磷化铟中金属杂质时。通常采用萃取法将基体铟分离.杂质富集浓缩后  相似文献   

9.
刘川楹  陈继  邓岳锋 《应用化学》2018,35(12):1492-1496
稀土元素钪(Sc)在相关原料中含量低,伴生杂质元素多,回收困难。针对这一问题,本文系统对比了直链三烷基氧化膦(Cyanex 923)、2-乙基己基磷酸单-2-乙基己基酯(P507)、环烷酸在硫酸体系中对Sc的萃取、分离和反萃。Cyanex 923在高酸度下能完全萃取Sc,而环烷酸和P507则在低酸度下有较高萃取率。Cyanex 923分离Sc与锆(Zr)、钛(Ti)的最佳水相酸度为1 mol/L,分离系数分别为5. 6和10. 6。P507在水相H~+浓度为2 mol/L时对Sc/Zr、Sc/Ti有最大分离系数,分别是21和59. 7。虽然P507有更好的分离效果,但难以反萃。3种萃取剂中仅有Cyanex 923能被有效反萃,在反酸H+浓度为0. 4 mol/L时有最大反萃率。因此,Cyanex 923更适合从含Sc二次资源浸出液中分离回收Sc。  相似文献   

10.
提出了以La(OH)3为共沉淀剂,对高纯氧化钨中的痕量金属杂质元素经共沉淀预分离富集后进行ICP-AES测定的分析方法。探讨了影响杂质元素回收率和钨残留量的若干因素,确定了合适的分离富集条件。合成试样和标准样品的测试结果表明: Bi、Ca、Cd、Co、Cu、Fe、Mg、Mn、Ni、Pb、Sb、Sn、Ti等元素能被定量分离回收,回收率和精密度均令人满意。  相似文献   

11.
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.  相似文献   

12.
Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.  相似文献   

13.
KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.  相似文献   

14.
The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.  相似文献   

15.
An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.  相似文献   

16.
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.  相似文献   

17.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

18.
The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion.  相似文献   

19.
A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.  相似文献   

20.
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