Thermoanalytical investigations of the decomposition course of copper oxysalts

The thermal decomposition course of copper acetate monohydrate (CuAc) was examined on heating up to 600°C at various rates, by TG, DTA and DSC. Non-isothermal kinetic and thermodynamic parameters were determined in air or nitrogen. SEM was used to describe the decomposition course and the solid products were identified by IR and XRD analysis. The results indicated that CuAc was dehydrated at 190°C and then partially decomposed at 220°C, giving rise to CuO in addition to a minor portion of Cu₂O and Cu₄O₃. The last two oxides seemed to facilitate the decomposition of the rest of the anhydrous acetate. Cu₂O and Cu₄O₃ were oxidized in air at >400°C, in a process that did not occur in nitrogen.It is a pleasure to thank the Queen's University of Belfast, particularly the staff of the Electron Microscope Unit for assistance in obtaining the electron micrographs. Thanks are also due to the Egyptian Government for the granted fellowship.     

Sol-Gel Derived Silica Films with Ultrafine Copper, Copper Sulfide and Copper Selenide Particles

A development of the silica-based sol-gel materials in the form of films containing ultrafine copper compounds and metallic copper is presented. Semiconductor nanoparticles with new optical features due to size effects and unique chemical properties of copper are produced. The chemical state of copper-containing dopants was manipulated by the sequence of chemical transformations monitored with XRD and optical absorption spectroscopy and discussed together with other recent data (XPS, TEM). A number of nanocrystalline phases of sulfides and selenides controllable by preparation conditions were detected in the films. The chemical composition of the dopants controls optical absorption both in the visible and near IR ranges.     

碘量法测定废杂铜屑中的铜含量

采用硝酸-盐酸溶解样品,在硫酸体系下加入氢溴酸,使得氢溴酸与试样中的砷、锑、锡等元素反应生成易挥发的溴化物,从而消除其干扰,滴定前用氟化氢氨掩蔽铁,在pH=3.0～4.0的范围采用碘量法测定废杂铜屑中的铜含量。用于测定金属样废杂铜屑中铜的含量,测定结果的相对标准偏差(RSD,n=7)为0.20%～0.25%,加标回收率在98.8%～101%,方法简单准确,能够满足日常检测需求。     

Zur Reaktion der Alkin‐Kupfer(I)‐Komplexe [CuCl(S‐Alkin)] und [Cu2Br2(S‐Alkin)(dms)] (S‐Alkin = 3,3,6,6‐Tetramethyl‐1‐thia‐4‐cycloheptin,dms = Dimethylsulfid) mit den Lithiumorganylen Phenyllithium und Fluorenyllithium

Organometallic Compounds of Copper. XX On the Reaction of the Alkyne Copper(I) Complexes [CuCl(S‐Alkyne)] and [Cu₂Br₂(S‐Alkyne)(dms)] (S‐Alkyne = 3,3,6,6‐Tetramethyl‐1‐thiacyclohept‐4‐yne; dms = Dimethylsulfide) with the Lithiumorganyls Phenyllithium und Fluorenyllithium The alkyne copper(I) bromide complex [Cu₂Br₂(S‐Alkyne)(dms)] ( 3 b ) (S‐Alkyne = 3,3,6,6‐tetramethyl‐1‐thiacyclohept‐4‐yne; dms = dimethylsulfide) reacts with phenyllithium to form a tetranuclear copper(I) complex of the composition [Cu₄(C₆H₅)₂(S‐Alkenyl)₂] ( 7 ) in low yield (4%). The reaction of the alkyne copper(I) chloride complex [CuCl(S‐Alkyne)] ( 2 a ) with fluorenyllithium in tetrahydrofuran (thf) affords a lithium cuprate of the composition [Li(thf)₄]⁺ [Cu₂(fluorenyl)₃(S‐Alkyne)₂]^– ( 8 ) (yield 32%). The structures of both new complexes 7 and 8 were determined by X–ray diffraction.     

CuI and CuII salts of group VIA elements as catalysts for living radical polymerization initiated with sulfonyl chlorides

The living radical polymerization of methyl methacrylate initiated from sulfonyl chlorides and catalyzed by the new catalytic systems Cu₂Y/Bpy and CuY/Bpy, where Y is O, S, Se, or Te and Bpy is 2,2′‐bipyridine, is described. An induction time was observed in all polymerization experiments. The values of the experimental rate constants of polymerization (k_p ^exp) increased whereas the corresponding induction times decreased in the order Y = O < S < Se < Te. For the entire series of catalysts, k_p ^exp for CuY was less than k_p ^exp for Cu₂Y. A mechanistic interpretation that involves the in situ generation of the CuCl/CuCl₂ pair, starting from Cu₂Y or CuY, is provided. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3839–3843, 2000     

碘量法测定铜锍中铜含量

根据铜锍的组成结构特点,建立了一种测定铜锍中铜含量的方法,重点讨论了混合酸对铜锍进行溶解的前处理及样品滴定过程。在4.80%~32.00%铜的测定范围内,加标回收率为97.70%~101.26%,相对标准偏差为0.24%~0.53%。方法能够较好地解决铜锍中铜含量测定难的问题。     

电解重量法测定混合铜矿中自由氧化铜

建立了用于混合铜矿石中自由氧化铜测定的方法。试样用含亚硫酸钠(6g/L)的硫酸(10%)溶液浸取2h,选择性溶解铜氧化物,过滤并煮沸滤液,用去离子水稀释后电解。溶液中的铜离子电积至阴极铂网上。用火焰原子吸收光谱法检测残余于电解后液中的铜离子;同时用硝酸(1+1)溶解铂网上的铜,并用火焰原子吸收光谱法检测与阴极铜共电积的杂质元素含量,用铂阴极差重加上电积后液残余铜含量并减去共电积的杂质元素含量可计算出氧化铜矿中酸溶铜含量。与碘量法相比,不用肉眼观察颜色变化确定终点,人为误差小,结果稳定、准确。通过对加拿大氧化铜矿标准物质AMIS0050进行测定(n=12),方法准确度可靠。并选取15批次的氧化铜矿检测,与经典碘量法比对,结果令人满意。     

碘量法与电重法测定氧化铜矿中酸溶铜的方法比较

试料用含亚硫酸钠的硫酸(10%)溶液浸取,使铜的氧化物矿物选择溶解,过滤后加入溴饱和盐酸掩蔽砷和锑等金属,补加少量硫酸,蒸干后用硫酸溶解,用硫代硫酸钠标准溶液滴定测定氧化铜矿中酸溶铜的含量,此方法快速、稳定、准确。选取14个日常分析的样品进行测定,其结果与电解重量法比对,结果令人满意。     

A Simple Coulometric Method for Determining Cu[II] and Cu[I] Contents in Various Solid Samples

Abstract

Determination of copper individual oxidation states (Cu[II] and Cu[I] in various solid samples is a rather difficult problem. Results are here presented to demonstrate that constant current coulametric techniques are useful to realize these determinations with good analytical characteristics. The analytical equivalence points obtained are based on the reversible electron transfer mechanisms: Cu[II] + 3 HC1 + 2 e CuCl^2? ₃ + 2H⁺ and : CuCl^2? ₃ +e = Cu(O) + 3 Cl^?, respectively, after quantitative dissolution in aqueous HC1 6 M. Cyclic voltammetric measurements with a carbon paste electrode are made to characterize the electron transfers involved and to investigate the analytical utility of the technique in various media. Analytical determinations are given, e.g., in the analysis of the CuO/Cu₂ O content of various samples.     

电重法测定混合铜矿中自由氧化铜的方法研究

本方法用于混合铜矿石中自由氧化铜的测定。试样用含0.6%（m/v）亚硫酸钠的10%(v/v)硫酸溶液浸取两小时,选择性溶解铜氧化物,过滤并煮沸滤液,用去离子水稀释后电解。溶液中的铜离子电积至阴极铂网上。用火焰原子吸收分光光度法检测残余于电解后液中的铜离子;同时用1 1硝酸溶解铂网上的铜,并用火焰原子吸收分光光度法检测与阴极铜共电积的杂质元素含量,用铂阴极差重加上电积后液残余铜含量并减去共电积的杂质元素含量可计算出氧化铜矿中酸溶铜含量。此方法相比国标碘量法,用肉眼观察颜色变化确定终点,人为误差小,结果稳定、准确。通过对加拿大氧化铜矿标准物质AMIS0050进行测定(n=12),方法准确度可靠。并选取十五批次的氧化铜矿检测,与经典碘量法比对,结果令人满意。     

Thermoanalytical investigation of the decomposition course of copper oxysalts

The thermal decomposition of copper nitrate trihydrate (CuNTH); Cu(NO₃)₂·3H₂O was studied up to 600°C by thermogravimetry (TG) and differential thermal analysis (DTA) in a dynamic atmosphere of air. The thermal events occurring throughout the decomposition course were characterized on the basis of spectral analyses using infrared spectroscopy (IR), X-ray diffractometry (XRD) and scanning electron microscopy (SEM). Non-isothermal kinetic parameters were determined. The results showed that the decomposition course involves two main processes, firstly the formation of hydroxy copper nitrate and secondly, the decomposition of this compound to yield CuO. Pathways were suggested that may be involved in the decomposition course.     

Voltammetric Measurement of [Cu(II)]/[Cu(I)] at a Platinum Rotating Disc Electrode and Control by Electrolysis at a Platinum Net Electrode in Chloride Solutions

ABSTRACT

A method has been described to measure and control the [Cu(II)]/[Cu(I)] bulk concentration ratio in aqueous chloride solutions. A variation of the ratio is achieved by controlled potential electrolysis at appropriate reducing or oxidizing potentials. The concentration ratio can be monitored by a repetitive double potential step amperometric method at a platinum rotating disc electrode. The amperometric signal can be used to control the electrolytic process in order to obtain and maintain a predetermined bulk concentration ratio. Diffusion coefficients of respectively 6.2 10^?6 and 5.6 10^?6 cm² s^?1 have been determined for Cu(II) and Cu(I). Potential applications of the method are the control of polymerisation reactions, of the reduction of textile dyes with the aid of a mediator system and of the colour characteristics of different kinds of glass.     

A Polarographic Method Determing Cu(II), Cu(I) and Metallic Copper Contents in Copper Oxide Samples

Abstract

A polarographic procedure was developed which permits the analysis of powdered cupric and cuprous oxides in the presence of metallic copper. To determine CuO, Cu₂O and metallic copper content in the sample two weight aliquots were used. The first aliquot was dissolved in medium of 50 % ethanol + 3 M hydrochloric acid + saturated ascorbic acid solution. Insoluable metallic copper was determined polarographically after its' separation and additional dissolving in concentrated nitric acid.

The second sample aliquot was dissolved in 6 M hydrochloric acid and the ratio of Cu(I) / Cu(II) in the solution was determined from the polarographic curves. To calculate CuO, Cu₂O and Cu content in a sample the proposed procedure was applied. The developed method provides the accurate results of the determination of CuO, Cu₂O and Cu content in a powdered mixture. The reproducibility expressed as the relative standard deviation is from 1 % to 5 %.     

Organocopper‐catalyzed living radical polymerization initiated with aromatic sulfonyl chlorides

The living radical polymerization of methyl methacrylate initiated from aromatic sulfonyl chlorides and catalyzed by the new catalytic systems CuSBu/bpy CuSPh/bpy and CuCCPh/bpy (bpy = 2,2′‐bipyridine) is described. For a target degree of polymerization of 200, lowering the ratio of catalyst to sulfonyl chloride group from 1/1 to 0.25/1 mol/mol decreases the values of the experimental rate constant of polymerization from 5.12 × 10⁻², 2.4 × 10⁻², and 1.87 × 10⁻² min⁻¹ to 1.8 × 10⁻³, 4.9 × 10⁻³, and 4.2 × 10⁻³ min⁻¹ for CuSBu, CuSPh, and CuCCPh, respectively, whereas the corresponding initiator efficiency increases from 62 to 99%. The external orders of reaction in the catalyst are 0.79 for CuSPh, 0.88 for CuCCPh, and 1.64 for CuSBu. A mechanistic interpretation that involves the in situ generation of, most likely, the real catalyst CuCl, starting from combinations of CuSBu, CuSPh, and CuCCPh and sulfonyl chloride or alkyl halide growing species, is suggested. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4353–4361, 2000     

婴幼儿铜代谢紊乱与疾病

铜与维持生命的许多生化作用有关，铜代谢紊乱与婴幼儿的许多疾病有着密切相关，可临床诊断和治疗效果的判断提供信息。     

The Coordination Chemistry of Copper Uptake and Storage for Methane Oxidation

Methanotrophs are remarkable bacteria that utilise large quantities of copper (Cu) to oxidize the potent greenhouse gas methane. To assist in providing the Cu they require for this process some methanotrophs can secrete the Cu-sequestering modified peptide methanobactin. These small molecules bind Cu^I with very high affinity and crystal structures have given insight into why this is the case, and also how the metal ion may be released within the cell. A much greater proportion of methanotrophs, genomes of which have been sequenced, possess a member of a newly discovered bacterial family of copper storage proteins (the Csps). These are tetramers of four-helix bundles whose cores are lined with Cys residues enabling the binding of large numbers of Cu^I ions. In methanotrophs, a Csp exported from the cytosol stores Cu^I for the active site of the ubiquitous enzyme that catalyses the oxidation of methane. The presence of cytosolic Csps, not only in methanotrophs but in a wide range of bacteria, challenges the dogma that these organisms have no requirement for Cu in this location. The properties of the Csps, with an emphasis on Cu^I binding and the structures of the sites formed, are the primary focus of this review.     

CuCl2 heterogenized on metformine‐modified polystyrene resin as an antibacterial agent and recyclable nanocatalyst for Ullmann‐type C‐N coupling reactions

Merrifield Resin was functionalized with metformine and applied as a solid support to immobilize the CuCl₂. The Ps‐Met/CuCl₂ was characterized by several techniques including Fourier transform infrared (FTIR), field emission scanning electron microscopy (FESEM), energy‐dispersive X‐ray spectroscopy (EDX), wavelength‐dispersive X‐ray spectroscopy (WDX) and inductively coupled plasma (ICP). The Ps‐Met/CuCl₂ was used as an efficient recyclable solid nanocatalyst for N‐arylation of indole and aniline through coupling reactions of Ullmann‐type C‐N. The advantages of this method are easy workup, improved yields, and simple recovery via filtration. Ultimately, the Ps‐Met/CuCl₂ antibacterial property was examined against two bacteria (Staphylococcus aureus (Staph. aureus) and Escherichia coli (E. coli)) and indicated its antibacterial performance against gram negative (E. coli) bacteria and gram positive (Staph. aureus).     

弹体堆焊铜带测试与分析

某产品的主体零件由弹体和铜带组成,弹体和铜带的传统结合方法是将紫铜或铜合金制成环状铜带,并镶嵌入弹体上的铜带槽内,这种生产方法的弹体与铜带之间是一种机械连接,其缺点为在挤压的过程中薄壁弹弹体易产生变形,有时还出现铜带松动现象,影响和制约该零件作用效果的提高.针对这种情况,提出铜带以TIG电弧焊,采用堆焊的方法将铜合金堆...     

高Tc超导体及相关化合物探索研究新进展

所有已知的层状铜氧化合物超导体结构均可按连接单元、分隔单元和三种不同的铜氧平面进行分类，由这几种基本的结构单元也可组合设计出新的结构类型，通过进一步的实验研究可以获得新结构类型的层状铜氧化合物超导体。以这一思想为出发点，本文从材料设计的角度总结了近五年来在新结构层状铜氧化合物超导体探索中的新进展。