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模糊聚类—偏最小二乘光度法同时测定锇钌 总被引:1,自引:0,他引:1
将模糊聚类分析与偏最小二乘相结合,对锇,钌双组份重叠光谱进行解析;较好地解决了校正分析中校准模型的优化问题,提高了分析结果的准确度;研究了锇,钌-SnCl2-乳化剂O-阿拉伯树胶-丁基罗丹明B高灵敏多元离子缔合物显色体系。锇,钌的检出限分别为0.632μg/L和0.368μg/L,模拟地质样品分析结果的相对误差小于±10%。 相似文献
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用刚果红离子缔合负载形成树脂分离Rh,Ir,Pt,Pd,Au的研究 总被引:3,自引:3,他引:3
研究了锇铱矿的锇钌蒸残液中Rh、Ir、Pt、Pd、Au的分离条件。于pH1.0的HCl介质中将贵金属吸附于刚果红负载形成树脂上,以分离贵贱金属。然后用0.5mol/LHCl洗脱Rh;3mol/LHCl洗脱Ir;0.5%的NaSCN-0.1mol/LHCl洗脱Pt;5g/L硫脲-0.1mol/LHCl洗脱Pd;50g/L硫脲-0.1mol/LHCl洗脱Au。洗脱顺序是Rh>Ir>Pt>Pd>Au。这五种贵金属的回收率在95%~101%之间。 相似文献
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水杨基荧光酮—过氧化氢催化动力学光度法测定痕量锇(Ⅳ) 总被引:5,自引:0,他引:5
在碱性介质中,痕量锇(Ⅳ)对水杨基荧光酮(SAF)与过氧化氢的氧化还原反应有显著的催化作用。本文以此为基础,提出用分光光度催化动力学测定痕量锇(Ⅳ)的新方法。本法未加掩蔽剂时的线性范围是0.08-0.80μg/L,加入掩蔽剂后的线性范围是0.08-0.80μg/L,检出限为0.08μg/L。本法用于实际样品中Os(Ⅳ)的测定,结果良好,本实验还测定了此催伦反应的活化能和反应级数。 相似文献
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1-(2-噻唑偶氮)-2-萘酚螯合物反相高效液相色谱法分离测定铜(Ⅱ)、铁(Ⅱ)和镍(Ⅱ) 总被引:1,自引:0,他引:1
以1-(2-噻唑偶氮)-2-萘酚(TAN)作柱前显色剂,于ODS柱上,用内含0.1mol/LLiCl,5×10-6mol/L TAN和HAc-NH4Ac缓冲溶液(pH 5.5)的甲醇-水溶液(80:20,V/V)作流动相,流速为0.6mL/min,并以紫外-可见检测器于590nm处进行检测,发展了一种RP-HPLC法同时分离测定铜(Ⅱ)、铁(Ⅱ)、镍(Ⅱ)的方法,方法灵敏度高,对于铜、铁、镍的检测限分别为1μg/L, 2 μg/L和 0.4 μg/L。用于实际样品测定,结果满意。 相似文献
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丁基罗丹明B-高碘酸盐动力学催化光度法测定纳克量钌 总被引:1,自引:0,他引:1
提出了在弱酸介质中钌催化高碘酸盐氧化丁基罗丹明B(BRB),以光度法测定钌。催化反应速率与催化剂浓度呈线性关系的范围为0.2~18ng/25m L,检出限为2.8×10- 12 g/m L。相对标准偏差小于14% 。催化反应对Ru(Ⅲ)、BRB、KIO4 和H3PO4 均为一级反应,表观活性能为42.12 kJm ol- 1。探讨了反应机理。本法已用于某些岩矿和冶金产品中钌的测定。RSD为1.02% ~2.29% ,回收率为98.7% ~102.0% 相似文献
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用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%. 相似文献
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Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
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
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The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula. 相似文献
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Rebecca J. Burton Mandy L. CrowtherNeal J. Fazakerley Shaun M. FilleryBarry M. Hayter Jason G. KettleCaroline A. McMillan Paula PerkinsPeter Robins Peter M. SmithEmma J. Williams Gail L. Wrigley 《Tetrahedron letters》2013
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
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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
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N. A. Nedolya 《Chemistry of Heterocyclic Compounds》2008,44(10):1165-1219
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
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Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products. 相似文献
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《Tetrahedron》2014,70(21):3377-3384
The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative. 相似文献
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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