Cupric Copper Research Articles

Extraction of Metals with Stearic Acid Involving Radioactive Nuclides

For the separation of metallic ions, stearic acid was introduced as a new extraction reagent. Solid low-melting point reagent such as stearic acid was expected to simplify the procedure of solvent extraction of metallic elements especially of radioactive isotopes and to do the disposal of radioactivity in the wastes. The extraction can be carried out by adding a solid stearic acid to the sample solution heated above its melting point (71 un. Concent 85% C) and by separating the solid stearic acid after being vigorously shaken with the solution and being left standing to solidify at room temperature. The extractabilities of fission products such as Sr/sup 90/-Y/sup 90/ Ce/sup 144/-Pr/sup 144/, Ru/sup 106/ -Rh/sup 106/, and al so of nonactive ferric iron and cupric copper were investigated as functions of pH. It was concluded that the above elements except Ru were extracted almost completely from the solution at pH around 7. (auth)

INTERFACE KINETICS: HYDROGEN PEROXIDE OXIDATION OF CUPROUS ION

It has been established (D. W. Colcleugh and W. F. Graydon. J. Phys. Chem. In press) that hydrogen peroxide is produced during the dissolution of polycrystalline copper in dilute aqueous solutions. The hydrogen peroxide formed during the dissolution further attacked the metal, producing additional cupric copper in solution. The kinetics of this heterogeneous reaction was investigated in aerated sulphuric acid solutions. Under these experimental conditions the ratio of the increase in concentration of cupric ion to the decrease in concentration of hydrogen peroxide was constant at the value of 2. In deaerated sulphuric acid this stoichiometric ratio was constant at the value of 1 under similar experimental conditions.Rate equations for the formation of cupric ion in solution and for the decomposition of hydrogen peroxide in the solution were determined as a function of sample area, corroding solution volume, temperature, hydronium ion concentration, cupric ion concentration, and hydrogen peroxide concentration.A reaction mechanism was suggested to describe the empirical rate equations and the stoichiometry obtained experimentally.

Pro-Oxidants in Spontaneous Development of Oxidized Flavor in Milk

Summary The objective of this study was to clarify the roles of copper, ascorbic acid, and xanthine oxidase in the spontaneous development of oxidized flavor in milk. At a mole ratio as low as 3.5 moles of neocuproine to one of copper, the cuprous chelator neocuproine effectively prevented oxidized flavor. Consequently, of the metals in milk, copper must have been the only one affected, indicating that it is an essential metal catalyst in lipid oxidation. Destruction of ascorbic acid by the relatively specific catalyst ascorbic acid oxidase prevented spontaneous peroxidation; but when the original ascorbic acid level was restored, spontaneous oxidized flavor developed. With less specific light and hydrogen peroxide treatments to destroy ascorbic acid, some anomalies were noted. It was concluded that at the copper concentrations normally present in milk, ascorbic acid is an essential reactant in spontaneous, as in copper-induced, oxidized flavor. At copper levels above 1μg/g, ascorbic acid was not necessary for lipid peroxidation, presumably because at the higher copper-protein ratios, protein substituted for ascorbic acid in reducing cupric copper to cuprous. In milk, in washed milk, and even in a model system containing only copper and a reducing agent in buffered linoleate, ascorbic acid was a more effective promoter of lipid oxidation than any other reducing agent tested. It is postulated that the pro-oxidant activity of ascorbic acid depends on its ability to reduce copper from cupric to cuprous, and on a specific association between copper and ascorbic acid that in some unexplained manner increases its pro-oxidant properties. A number of experiments was directed toward establishing a role for xanthine oxidase in lipid oxidation reactions, but no consistent results were obtained to support the hypothesis that spontaneous development of oxidized flavor depends on the activity of xanthine oxidase in milk.

Simultaneous determination of dichromate and cupric ions

The stage-wise reaction of titanous chloride with a mixture of dichromate and cupric copper is used as the basis of a rapid method for the determination of the individual components of the mixture cited. Diphenylamine is used as indicator for the first reaction while a few drops of ferrous solution in the presence of excess thiocyanate serve as indicator for the second reaction.

Polarographic Studies on the Complex Between Cupric Copper and Cystine

Polarographic Studies on the Complex Between Cupric Copper and Cystine

A new rapid titrimetric method for copper

A rapid and simple titrimetric method for the estimation of copper is described. Hydrochloric acid solution of cupric copper is titrated directly with stannous chloride in the presence of thiocyanate using a few drops of 2% ammonium molylbdate solution as indicator.

Purification and physico-chemical properties of laccase

Laccase of Rhus vernicifera was purified by column chromatography on an ion-exchange resin and zone electrophoresis. The purity was confirmed by sedimentation and electrophoresis. It was revealed that the enzyme molecule has a molecular weight of 120,000 and carries four atoms of cupric copper per molecule. The oxidation-reduction potential of the enzyme was measured spectrophotometrically in the presence of ferrocyanide-ferricyanide system. The E 0′ value found was + 415 mV at 25° and pH 7.0. The purified enzyme showed two absorption maxima at 280 mμ and 615 mμ with a shoulder at 330 mμ.

The coulometric titration of bromate with cuprous copper

A coulometric procedure has been developed by which 18 to 240 μg quantities of bromate may be determined to within 0.3 μg. The bromate is allowed to react with bromide in an acid solution and electrolytically generated cuprous copper is used for the titration. A dual platinum electrode indicator system is used in an amperometric end-point procedure

The Association of 4-Methylimidazole with the Ions of Cupric Copper and Zinc; with Some Observations on 2,4-Dimethylimidazole

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Association of 4-Methylimidazole with the Ions of Cupric Copper and Zinc; with Some Observations on 2,4-DimethylimidazoleYasuhiko Nozaki, Frank R. N. Gurd, Raymond F. Chen, and John T. EdsallCite this: J. Am. Chem. Soc. 1957, 79, 9, 2123–2129Publication Date (Print):May 1, 1957Publication History Published online1 May 2002Published inissue 1 May 1957https://doi.org/10.1021/ja01566a025RIGHTS & PERMISSIONSArticle Views250Altmetric-Citations61LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (853 KB) Get e-Alerts Get e-Alerts

Metallic components of fruit juices. II.—The nature of some copper complexes in apple juice

AbstractThe interaction of cupric copper with the organic acid, amino‐acid and phenolic components of apple juices has been investigated in juices and model systems. Copper is mainly complexed with malic acid and the dissociation constant of this complex has been calculated; the proportion of copper complexed with amino‐acids is small. Copper forms soluble complexes with the phenolics at the pH of juices, with reduction of cupric copper to the cuprous state and leading to the precipitation of copper and partly degraded phenolics. The significance of these findings is discussed in relation to the storage behaviour of apple juices.

The determination of copper by complexometric titration with ethylenediaminetetraacetic acid

A method has been developed for the determination of cupric copper by complexometric titration with ethylen.ediaminetctraacetic acid. The titrations were followed potentiometrically, and were effected at pH 5–6 in the presence of an ammonium acetate buffer. Interfering metals such as ferric iron, aluminium, cadmium, zinc, manganese, nickel, cobalt and lead must be removed by a preliminary separation.

The Association of Imidazole with the Ions of Zinc and Cupric Copper1a,b,c

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Association of Imidazole with the Ions of Zinc and Cupric Copper1a,b,cJohn T. Edsall, Gary Felsenfeld, DeWitt S. Goodman, and Frank R. N. GurdCite this: J. Am. Chem. Soc. 1954, 76, 11, 3054–3061Publication Date (Print):June 1, 1954Publication History Published online1 May 2002Published inissue 1 June 1954https://doi.org/10.1021/ja01640a068RIGHTS & PERMISSIONSArticle Views1444Altmetric-Citations138LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (907 KB) Get e-Alerts Get e-Alerts

Quinquevalent tungsten as a reducing agent in potentiometric titrations

Qmnquevalcnt tungsten prepared by the electrolytic reduction of tungstate in ION HC1 is sufficiently stable when kept in strong acid solutions under COg to be used as an effective reducing agent in potcntiometric titrations. It can be accurately standardised with dichromate. The formal redox potentials of the W +6 W +5 system as determined at different acidities indicate that quinquevalent tungsten is more reducing than the corresponding molybdenum compound. Quinquevalent tungsten can be applied successfully as a volumetric reagent in the potentiometric titration of ferric iron in 8-ioN HC1 or in a mixture of HCl and H3PO4 0.5.N each and of cupric copper in 8N HCl at 80° C. It can also be applied for the estimation of iodate, provided that the latter is used as the titrant.

The Copper Technique for Dyeing Acrylonitrile Fibers

The use of small amounts of dissolved copper in the dye bath to improve the dyeing of acrylonitrile fibers is described. Cuprous copper, obtained by reducing cupric acetate or sul fate in the dye bath, is the preferred form. The technique appears to be specific to acrylonitrile fibers, and is most effective with acid, direct, and soluble acetate dyes. Data on sorption of cop per and of other metal ions by acrylonitrile fibers and various non-acrylonitrile fibers are pre sented, and possible complexes between copper ions and polymeric acrylonitrile are postulated.

Polarographic Investigations of Reactions in Aqueous Solutions Containing Copper and Cysteine (Cystine). I. Cuprous Copper and Cysteine in Ammoniacal Medium. The Dissociation Constant of Cuprous Cysteinate

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPolarographic Investigations of Reactions in Aqueous Solutions Containing Copper and Cysteine (Cystine). I. Cuprous Copper and Cysteine in Ammoniacal Medium. The Dissociation Constant of Cuprous CysteinateW. Stricks and I. M. KolthoffCite this: J. Am. Chem. Soc. 1951, 73, 4, 1723–1727Publication Date (Print):April 1, 1951Publication History Published online1 May 2002Published inissue 1 April 1951https://doi.org/10.1021/ja01148a087RIGHTS & PERMISSIONSArticle Views210Altmetric-Citations53LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (592 KB) Get e-Alerts Get e-Alerts

Mercurous nitrate as a reductimetric reagent : The determination of copper

It has been found that in the presence of excess thiocyanate ions, cupric copper will oxidise ferrous ions. Use has been made of this reaction to determine copper by titration of the ferric iron produced, with mercurous nitrate. Although this reaction is the reverse of that usually observed, where the cuprous ion reduces the ferric iron, it has been found that the large excess of thiocyanate is responsible for this effect.

Destruction of cyanide in waste waters by chlorination

AbstractA study of the reactions of sodium and calcium hypochlorites with buffered alkaline solutions of potassium cyanide indicated that the first product was always cyanogen chloride, which was rapidly hydrolysed at pH II or above without further absorption of available chlorine. At lower pH values additional chlorine was absorbed up to a total of 5·75 gram‐atoms per gram‐molecule of cyanide. At pH II the reaction of hypochlorites with the complex cyanides of zinc and cadmium was similar to that with potassium cyanide; cupro‐cyanide was also rapidly attacked, with oxidation of cuprous copper to the cupric state, but nickelocyanide was only slowly attacked.A process was developed for treating electroplating wastes, or other waste waters containing cyanide, by reaction with calcium hypochlorite at pH II. The process would be applicable to liquids containing simple cyanides and the complex cyanides of zinc, cadmium, and copper, but not to solutions containing nickel.

Studies on the Ammoniacal Copper Solutions I The Reaction Order of the Reduction by Carbon Monoxide and a Correction for the Escaping Carbon Monoxide

Abstract 1. It is experimentally verified that the reduction of cupric copper by the carbon monoxide absorbed in the copper solution is a reaction of the second order. 2. In the calculation of the velocity constant for the reduction, it is found that the correction made for the carbon monoxide escaping unreacted, under the assumption that the escaping velocity of the carbon monoxide is proportional to its concentration in the solution at that time, is appropriate.

The Coulometric Titration of Chromate and of Vanadate by Means of Electrolytically Generated Cuprous Copper and an Amperometric End-Point

The Coulometric Titration of Chromate and of Vanadate by Means of Electrolytically Generated Cuprous Copper and an Amperometric End-Point

Microdetermination of Copper in Biological Substances

IN the course of a series of investigations by F. Buscarons and E. Loriente1,2 on analytical applications of 3,3', 4,4'-diamine-3,3'-dimethoxy-biphenilo (o-dianisidin), these authors have shown that this substance in certain conditions possesses extreme sensitivity for cupric copper. We have used this reactant for colorimetric determinations of copper in the blood and in other biological substances.