The Simultaneous Spectrophotometric Determination of Osmium and Ruthenium

Abstract

A spectrophotometric procedure is described for the simultaneous determination of osmium and ruthenium in the form of bromo complexes. It was found that a blue ruthenium-thiourea complex could be formed in 6.7 M HBr solutions while the osmium could be maintained as the hexabromoosmate complex. Absorption maxima were at 620 μ for the ruthenium complex and at 446 μ for the osmium complex. Molar absorptivities for the ruthenium complex were 2.47 × 10³ at 620 μ and 763 at 446 μ. For the osmium complex molar absorptivities were 328 at 620 μ and 6.81 × 10³ at 446 μ. The method is useable over the range of 5 to 30 ppm with an absolute error of = 1 ppm over the range. Other platinum metals interfere.     

高碘酸盐氧化罗丹明B催化光度法测定钌

在０．７２ｍｏｌ／Ｌ磷酸和９０℃水浴条件下,钌催化高碘酸盐氧化罗丹明Ｂ（ＲＢ）,据此建立了高灵敏催化光度测定钌的方法。方法的检出限为８．０×１０＾－１２ｇ／ｍＬ,测定范围为０．２～１５ｎｇ／２５ｍＬ,对５、１０、１５ｎｇ／２５ｍＬＲｕ（Ⅲ）测定的相对标准偏差分别为８．６７％,５．９４％和１．８５％。本反应对Ｒｕ（Ⅲ）、ＲＢ、ＫＩＯ４和Ｈ３ＰＯ４均为一级反应,表观活化能为３６．０５ｋＪ／ｍｏｌ。１３     

流动注射催化分光光度法测定钌的研究

利用钌（Ⅲ）对过氧化氢氧化还原型百里酚酞显色反应的显著催化作用，建立了钌的新流动注射催化分光光度分析法，该法快速灵敏、简便，用于实际样品分析，结果良好。     

活性炭负载钌系氨合成催化剂中钌含量的分析

采用分光光度法测定活性炭负载钌系氨合成催化剂中的钌含量．在强酸和乙醇体系中,Ru（Ⅲ）与硫脲生成蓝色物,于最大吸收波长λ=620am处测定催化剂中的钌含量．测试结果表明,该方法操作简单、干扰小,相对标准偏差为1％～3％,加标回收率在97．5％～102．0％之间,适用于活性炭负载钌系氨合成催化剂中钌含量的准确测定．     

耐尔蓝-高碘酸钾催化光度法测定痕量钌

在磷酸介质和加热条件下,钌（Ⅲ）对高碘酸钾氧化耐尔蓝（ＮＢ）有强催化作用,详细研究了动力学条件,建立了动力学光度测定钌的新方法,１g（Ａ０／Ａ）与ＣＲu（Ⅲ）呈线性关系的范围为０．００８～１．２ｕｇ／Ｌ,检出限为０．００８ｒｇ／Ｌ,对０．００８和０．８ｕｇ／ＬＲｕ（Ⅲ）测定的ＲＳＤ分别为１４．３０％６和１．７３（n＝１１ ）。本催化反应对Ｒu（Ⅲ）、ＮＢ和ＫＩＯ４为一级反应,表观活化能为７３．４３ＫＪ     

Single‐Atom Catalyst of Platinum Supported on Titanium Nitride for Selective Electrochemical Reactions

As a catalyst, single‐atom platinum may provide an ideal structure for platinum minimization. Herein, a single‐atom catalyst of platinum supported on titanium nitride nanoparticles were successfully prepared with the aid of chlorine ligands. Unlike platinum nanoparticles, the single‐atom active sites predominantly produced hydrogen peroxide in the electrochemical oxygen reduction with the highest mass activity reported so far. The electrocatalytic oxidation of small organic molecules, such as formic acid and methanol, also exhibited unique selectivity on the single‐atom platinum catalyst. A lack of platinum ensemble sites changed the reaction pathway for the oxygen‐reduction reaction toward a two‐electron pathway and formic acid oxidation toward direct dehydrogenation, and also induced no activity for the methanol oxidation. This work demonstrates that single‐atom platinum can be an efficient electrocatalyst with high mass activity and unique selectivity.     

A Simple Sensitive Spectrophotometric Method for the Determination of Ce4+ Using Variamine Blue as a Chromogenic Reagent

A rapid and sensitive spectrophotometric method is described for the determination of trace amounts of cerium using Variamine Blue (VB) as a chromogenic reagent. The proposed method is based on the reaction of cerium with potassium iodide in acidic medium to liberate iodine, which oxidizes Variamine Blue to give a violet colored species with an absorption maximum at 560nm. Beers law was obeyed in the range 2–10µg mL^–1 of cerium. The molar absorptivity and Sandells sensitivity are found to be 1.65×10⁴L mol^–1cm^–1 and 8.48×10^–3µgcm^–2, respectively. The proposed method has been successfully applied to the determination of cerium in alloy and synthetic mixtures.     

活性炭负载Pt-Fe双金属催化剂催化对氯硝基苯选择性加氢

采用浸渍还原法制备了活性炭负载Pt-Fe双金属催化剂(Pt-Fe/AC),考察了其催化对氯硝基苯加氢性能。 与Pt/AC催化剂比较,该催化剂对催化对氯硝基苯加氢表现出高活性和优异的抑制脱氯性能,在乙醇为溶剂、催化剂Pt_0.003-Fe_0.04/AC(下标为元素在催化剂中的质量分数)用量为0.02 g/g对氯硝基苯、1 MPa H₂和30 ℃条件下反应150 min,对氯硝基苯完全转化为对氯苯胺,而且即使在较高的反应温度和H₂压力下,脱氯反应也得到了完全抑制。 采用X射线衍射(XRD)、透射电子显微镜(TEM)及X射线光电子能谱(XPS)等技术手段对Pt-Fe/AC催化剂进行了表征。 结果表明,Pt、Fe高度分散在活性炭上,Pt与Fe之间的相互作用对纳米Pt粒子的电子结构有一定的调变作用,使纳米Pt处于缺电子态,减弱了Pt与对氯苯胺苯环之间的电子反馈,这可能是Pt-Fe/AC对催化对氯硝基苯加氢表现出高活性和优异的抑制脱氯性能的主要因素。     

邻苯二酚紫退色光度法测定微量锰(Ⅱ)

在硫酸介质中．高锰酸根氧化邻苯二酚紫使其退色，退色程度在一定范围内与高锰酸根加入量成良好的线性关系。据此建立了一种测定微量锰（Ⅱ）的新方法。最大吸收波长λmax＝550nm，表观摩尔吸光系数ε＝4．2×104L·mol-1·cm－1·。锰（Ⅱ）量在0－0．8mg／L范围内符合比耳定律．方法应用于求和面粉中微量锰（Ⅱ）的测定，结果满意。     

氯对钌基氨合成催化剂的影响

氯离子的脱除是制备高性能钌催化剂的一个重要步骤。本文综述了新型钌基氨合成催化剂制备过程中的脱氯环节。介绍了以RuCl₃·3H₂O作为活性前驱体的钌催化剂中氯离子的来源、氯在催化剂中的存在方式、它对催化剂的毒害作用以及去除氯离子的方法。     

催化动力学光度法测定钌

在磷酸介质中,痕量钌（Ⅲ）对溴酸钾氧化二安替比林对氨基苯基甲烷（DApAM）的显色反应具有明显的催化作用,研究了反应的最佳条件,并测定了一些动力学参数,据此建立了一种测定痕量钌（Ⅲ）的新方法,其检测限为2．10×10－9g／mL,针含量在0－20μg／L内符合比尔定律,方法用于贵金属精矿中痕量钌的测定,结果满意。     

A New Spectrophotometric Method for the Determination of Arsenic in Environmental and Biological Samples

Abstract

A simple and selective spectrophotometric method has been developed for the determination of trace amounts of arsenic using azure B as a chromogenic reagent. The proposed method is based on the reaction of arsenic(III) with potassium iodate in acid medium to liberate iodine. The liberated iodine bleaches the violet color of azure B and is measured at 644 nm. This decrease in absorbance is directly proportional to the As(III) concentration, and Beer's law is obeyed in the range 0.2–10 µg ml^?1 of As(III). The molar absorptivity, Sandell's sensitivity, detection limit, and quantitation limit of the method were found to be 1.12×10⁴ l mol^?1cm^?1, 6.71×10^?3 µg cm^?2, 0.02 µg ml^?1 and 0.08 µg ml^?1, respectively. The optimum reaction conditions and other analytical parameters were evaluated. The proposed method has been successfully applied for the determination of arsenic in various environmental and biological samples.     

对碘偶氮氯膦-高碘酸钾-钌(Ⅲ)的褪色反应用于痕量钌的催化分光光度法测定

在Ｈ２ＳＯ４ 介质中对碘偶氮氯膦与高碘酸钾的褪色反应只有在痕量钌（Ⅲ）的存在下才能定量进行。本文研究了该褪色反应的最佳条件及用于痕量钌的测定方法, 其检出限为０．０２ μｇ·１０ ｍ Ｌ－ １, 钌含量在０．０２～０．３０ μｇ·１０ ｍ Ｌ－ １范围内符合比尔定律。该方法用于贵金属精矿中钌含量的测定, 获得满意结果。     

Simple and Simultaneous Method for Determination of Palladium(II) and Ruthenium(III) using Second-Order-Derivative Spectrophotometry

Abstract

A simple, sensitive, and selective second-order-derivative spectrophotometric method has been developed for the simultaneous determination of palladium(II) and ruthenium(III) using 2-hydroxy-3-methoxy benzaldehyde thiosemicarbazone (HMBATSC) as a chromophoric reagent. The reagent (HMBATSC) reacts with Pd(II) and Ru(III) at pH 3.0, forming soluble yellowish green and dark brown species, respectively. Palladium and ruthenium present in the mixture were simultaneously determined without solving the simultaneous equations by measuring the second derivative amplitudes at 445 nm and 385 nm, respectively. Further, the Beer's law was obeyed in the range 0.21–12.78 µg mL^?1 and 0.25–13.42 µg mL^?1 for Pd(II) and Ru(III), respectively. A large number of foreign ions did not interfere in the present method. The proposed method was successfully applied for the determination of palladium in hydrogenation catalysts and ruthenium in water samples.     

二安替比林对二甲氨基苯基甲烷-高碘酸钾催化光度法测定痕量钌

在磷酸介质和加热条件下,钌（Ⅲ）对高碘酸钾氧化二安替比林对圩甲氨基苯基甲烷（ＤＡＭＡＭ）的显反色应脸强催化作用,建立了催化动力学光度法测定痕量钌的新。方法的线性范围为０－５．４μｇ／Ｌ;检出限为２．１６＊１０＾－８ｇ／Ｌ;对２μｇ／Ｌ的Ｒｕ（Ⅲ）测定的ＲＳＤ为２．２９％（ｎ＝１１）。催化反应的表观活能为９２．２３ｋＪ／ｍｏｌ。考察了４０多种共存离子的影响。大多数常见离子不干扰测定。本法已用于矿样中     

Spectrophotometric Determination of Azide Ion Through Carbon Disulphide - Azide Reaction

Abstract

The azide ion can be converted quantitatively into 1,2,3,4, - thiatriazol - 5 - thiolate ion by treatment with carbon disulphide in aqueous ethanolic medium. The CS₂N₃ ^? concentration is measured spectrophotometrically at 321nm, where ?= 7. 8 × 10³ l mol^?1 cm^?1. The conditions outlined below provide a rapid, simple and precise method to determine the azide ion at the 8 μg/ml level.The influence of several foreign ions on the proposed method is also studied.     

褪色光度法测定氯酸根离子

研究了在盐酸介质中，氨酸根氧化甲基橙使其褪色的最佳条件，提出了一种测定微量氨酸根离子的新方法。最大吸收波长λmax=510nm，表观摩尔吸光系数ε=1．0×105L.mol-1·cm-1，氨酸根离子浓度在0．2－0．6mg／Ｌ范围内符合比耳定律。本法快速、简便、选择性好，可用于化学试剂中氯酸根离子的测定，结果满意。     

多壁碳纳米管负载铂的甲苯加氢脱芳催化剂

以多壁碳纳米管(CNTs)为载体制备了负载型Pt催化剂Pt/CNTs并将其用于催化甲苯加氢脱芳(HDA)反应.结果表明,在1.0%Pt/CNTs催化剂上,在0.4MPa,373K,PhCH3/H2摩尔比=6/94和GHSV=120L/(h.g)的反应条件下,甲苯转化率可达100%,比反应速率为0.0523mmol/(s.m2),分别是γ-Al2O3和AC负载各自最佳Pt负载量催化剂1.4%Pt/γ-Al2O3和2.4%Pt/AC上相应值的1.17和1.18倍.甲苯加氢产物全部为甲基环己烷,其他可能的加氢产物均在气相色谱检测限以下.催化剂的表征研究揭示,用CNTs代替γ-Al2O3或AC作为载体并不会引起所负载Pt催化剂上甲苯HDA反应的表观活化能发生明显变化.与γ-Al2O3或AC负载的相应催化剂相比,一方面,CNTs负载的Pt催化剂易于在较低温度下还原活化,并且其工作态催化剂表面催化活性Pt物种(Pt0)所占表面Pt摩尔分率有所提高;另一方面,CNTs负载的Pt催化剂对H2具有较高的吸附/活化和储存能力.这些促进效应对催化剂HDA活性的提高都有重要贡献.