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DBC-偶氮胂-锇-溴酸钾催化光度法测定微量锇 总被引:1,自引:0,他引:1
酸性介质中 Os( )对溴酸钾氧化 DBC-偶氮胂的褪色反应有明显的催化作用 ,据此反应建立了微量锇的催化光度分析法 ,锇在 1 .0~ 2 0 .0 μg·L- 1 符合比耳定律。反应在水相中进行 ,灵敏度高 ,简便快速 ,用于贵金属精矿中锇的测定 ,结果满意。 相似文献
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酸性介质中Os(Ⅳ)对溴酸钾氧化DBC-偶氮肿的褪色反应有明显的催化作用,据此反应建立了微量娥的催化光度分析法,锇在1.0-20.0μg·L-1符合比耳定律.反应在水相中进行,灵敏度高,简便快速,用于贵金属精矿中娥的测定,结果满意. 相似文献
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Ir(Ⅲ)-偶氮胂DBM-KIO4催化分光光度法测定微量铱 总被引:2,自引:0,他引:2
在H2SO4介质中,微量铱的存在对KIO4-偶氮胂DBM的褪色反应有明显的催化作用,探讨了该褪色反应的最佳条件及微量铱的测定方法,检出限为0.1μg/mL,铱含量在0.1~1.0μg/mL范围内符合比尔定律. 相似文献
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DBC—偶氮胂—锇—溴酸钾催化光度法测定微量锇 总被引:1,自引:0,他引:1
酸性介质中Os(Ⅳ)对溴酸钾氧化DBC-偶氮肿的褪色反应有明显的催化作用,据此反应建立了微量娥的催化光度分析法,锇在1.0-20.0μg·L-1符合比耳定律。反应在水相中进行,灵敏度高,简便快速,用于贵金属精矿中娥的测定,结果满意。 相似文献
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催化动力学分光光度法测定微量铅的研究 总被引:10,自引:0,他引:10
本文报道在NH3-NH4C1介质中,利用铅催化H2O2氧化胭脂红腿色这一反应,建立催化动力学光度法测定微量铅的新方法。方法的检出限为0.091μg/25mL,线性范围0.10-0.90μg/25mL,用于分析汽油中的铅,结果满意。 相似文献
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以Os(Ⅳ )催化高碘酸钾氧化丽春红G(PG)的褪色反应为基础 ,在 90℃加热 1 2min和 5 0 0nm波长处采用固定时间法测定丽春红G吸收值的降低 ,建立了测定痕量锇 (Ⅳ )的新方法。锇 (Ⅳ )的质量浓度在 0~ 0 48μg/L范围内呈良好的线性关系 ,检出限为 6 2× 1 0 - 9mg/L。对 0 4μg/L锇 (Ⅳ )测定的相对标准偏差为 0 71 % (n =1 1 )。催化反应对Os(Ⅳ )和丽春红G均为一级反应 ,催化反应的表观活化能为 78 80kJ/mol。所提出的方法在蒸馏分离后已应用于某些岩矿及冶金产品中锇的测定 相似文献
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Peter W. Roesky Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(27):4892-4894
Excellent couplings : Recent developments in the metal‐catalyzed C? H activation of sp3 centers in an α position relative to an amine nitrogen atom are presented. Their reaction with alkenes to give alkylamines (hydroaminoalkylation) is also summarized (see general scheme).
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Peter G. Schultz 《Angewandte Chemie (International ed. in English)》1989,28(10):1283-1295
The vast binding repertoire of the immune system has been exploited for the generation of tailor-made biological catalysts. A number of strategies have been developed to generate catalytic antibodies that carry out a wide range of reactions with exquisite specificities. The generation and characterization of these novel catalysts is not only providing new insights into the nature of biological recognition and catalysis, but may also lead to novel catalysts for applications in chemistry, biology, and medicine. 相似文献
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Catalytic Applications of Aerogels 总被引:1,自引:0,他引:1
This paper is a review of studies on aerogel synthesis and its application for catalytic uses, which have been conducted for
the past decade at the Clean Technology Research Center, Korea Institute of Science and Technology. Various organic and inorganic
aerogels employing sol–gel modifications exhibited catalytically favorable textural and chemical properties such as extremely
high porosity, high surface area, well-developed mesoporosity, good thermal stability, and high dispersion, which eventually
led to excellent performance in catalytic reactions. Reactions observed in these studies include hydrogenation, photodecomposition,
selective oxidation, complete oxidation, ammoxidation, reforming, and electrooxidation. The specific catalytic behaviors can
be explained in terms of the strong active sites-support interactions, high thermal stability, and extremely high dispersion. 相似文献
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Catalytic decomposition of CCI2F2 was studied over a number of single and complex metal oxides using a fixed-bed reactor. The ZrO2–Cr2O2 catalyst exhibited the highest activity and CO2 and CCIF3 were formed at 350–450°C. Selective decomposition of CCI2F2 required the presence of both oxygen and water vapor over the catalyst. Catalytic activity gradually declined with time on stream because of the fluorination of ZrO2. Treatment of the catalyst with both oxygen and water vapor promoted the removal of fluoride ions in sub-surface layers of the catalyst, which is effective for the recovery of the activity. CCI2F2 was decomposed at 300–450°C over AIPO4. No fluorination of the AIPO4 catalyst took place after the reaction for 1000 h. CH2FCF3, an alternative CFC, was completely decomposed over the mixed catalyst of Ce promoted AIPO4 and Cr2O3 at 400–500°C. Catalytic decomposition is a rational method for destruction of used CFCs. 相似文献
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Juan Urbano Brigitte Korthals M. Mar Díaz‐Requejo Pedro J. Pérez Stefan Mecking 《Journal of polymer science. Part A, Polymer chemistry》2010,48(20):4439-4444
Catalytic cyclopropanation of commercial 1,2‐ or 1,4‐cis‐polybutadiene, respectively, with ethyl diazoacetate catalyzed by [TpBr3Cu(NCMe)] (TpBr3 = hydrotris(3,4,5‐tribromo‐1‐pyrazolyl)borate) at room temperature afforded high molecular weight (Mn > 105 mol?1) side‐chain or main‐chain, respectively, carboxyethyl cyclopropyl‐substituted polymers with variable and controlled degrees of functionalization. Complete functionalization of 1,4‐cis‐polybutadiene afforded poly[ethylene‐alt‐(3‐ethoxycarbonyl‐cyclopropene)]. Catalytic hydrogenation of residual double bonds of partially cyclopropanated polybutadienes provided access to the corresponding saturated polyolefins. Thermal properties are reported. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(49):15909-15913
We have developed a catalytic method for the hydroalkylation of allenes using alkyl triflates as electrophiles and silane as a hydride source. The reaction has an excellent substrate scope and is compatible with a wide range of functional groups, including esters, aryl halides, aryl boronic esters, sulfonamides, alkyl tosylates, and alkyl bromides. We found evidence for a reaction mechanism that involves unusual dinuclear copper ally complexes as catalytic intermediates. The unusual structure of these complexes provides a rationale for their unexpected reactivity. 相似文献
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E. I. Goryunov G. N. Molchanova P. V. Petrovskii L. S. Zakharov M. I. Kabachnik 《Russian Chemical Bulletin》1998,47(9):1728-1731
Phosphorylation of α-polyfluoroalkylbenzyl alcohols by an excess of phenylphosphonic dichloride in the presence of Mg or CaCl2 as the catalyst givesO-(α-polyfluoroalkylbenzyl) phenylphosphonochloridates (63–79% yield). The reaction proceeds stereoselectivity, and the phosphonochloridates
obtained are mixtures of two diastereomers with predominance (approximately by 10%) of one of them.
For Part 15, see Ref. 1.
Deceased.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1776–1779, September, 1998. 相似文献