Solutions Of Copper Salts Research Articles

Thermodynamic molar properties of aqueous solutions of copper salts using sound velocity measurements

Abstract The partial molar volumes and compressibilities of copper m-benzene disulphonate , copper acetate , copper perchlorate , copper nitrate and copper sulfate are calculated from densities and sound velocity measurements at 25°C . The investigated concentration range is between 0.01 and 1 molar . The partial molar volume at infinite dilution was found to decrease in the following order ; copper mbenzene disulphonate > copper(II) acetate > copper(II) perchlorate > copper(II) nitrate > copper(II) sulfate . However , the apparent molar compressibilities at infinite dilution were found to follow the trend ; copper(II) sulfate > copper m- benzene disulphonate > copper (II) perchlorate > copper (II) nitrate > copper (II) acetate

Methanol-reforming reaction over copper-containing catalysts—The effects of anions and copper loading in the preparation of the catalysts by kneading method

Methanol-reforming reaction CH 3OH + H 2O = 3H 2 + CO 2 was carried out over copper-containing catalysts which were prepared from hydroxides of copper or from the hydroxide kneaded with various metal oxides. The specific activity (activity per weight of copper used) either of supported or support-free catalyst was markedly increased when the hydroxide was prepared from alkali solution with addition of copper salt solution at higher pH or when the weight percentage of copper on the support was decreased. However, other kinetic parameters such as activation energy and selectivity of the reaction were unaffected by the preparation of the catalyst unless copper chloride was employed as a starting material of the hydroxide preparation at lower pH. DTA, ir, XPS, AES and other chemical analyses of the catalysts revealed that hydroxide ion in the hydroxide precipitate prepared at lower pH exchanged in part with the anionic group of its starting material during the course of the preparation. The anion or its fragment was found to be strongly held on the surface and inhibited the reaction to a great extent. On the other hand, the anion held was markedly decreased when the catalyst was prepared at higher pH. This catalyst was found to be highly active for the title reaction. The surface area of metallic copper was considerably increased when copper was kneaded with the support. This gave rise to the increase in the specific activity of the catalyst. The effect of the support upon the reaction was examined for the catalyst kneaded with silica, manganese dioxide, ferric oxide, titanium oxide, calcium oxide, and nickel oxide. However, the supports other than nickel oxide exerted no chemical effect upon the reaction. Nickel oxide was suggested to be reduced during the course of the reaction and metallic nickel thus formed catalyzed the methanol decomposition reaction CH 3OH = CO + 2H 2.

Separation and identification of aminocarboxylic acid sequestrants by high-performance liquid chromatography

A simple method has been developed for the separation by high-performance liquid chromatography of some common aminocarboxylic acid sequestrants as their copper complexes. The copper complex is formed in situ by using a copper salt solution as the eluate. Detection using visible light at 760 nm eliminates interference from ultraviolet absorbing compounds often present in mixtures containing sequestrants.

Ammine adduct and Schiff base formation in the copper(II) 1,1,1,5,5,5-Hexafluoropentane-2,4-dione-ammonia system

1,1,1,5,5,5-Hexafluoropentane-2,4-dione (Hhfa) reacts with ammoniacal solutions of copper(II) salts at room temperature to form the ammine adducts Cu(hfa)2,NH3 and Cu(hfa)2,2NH3, and at elevated temperatures or on standing to form the Schiff base complex Cu(hfacim)2 (Hhfacim = 1,1,1,5,5,5-hexafluoro-4-aminopentan-2-one) The magnetic susceptibility data for Cu(hfacim)2 suggest the presence of exchange interaction and is best explained by using a S = � Heisenberg chain model with J=-0.18 cm-1.

Cuprous hydrometallurgy Party VI. Activation of chalcopyrite by reduction with copper and solutions of copper(I) salts

Chalcopyrite is reduced by solutions of copper(I) sulfate and copper(I) chloride to chalcocite (Cu 2S) and bornite (Cu 5FeS 4) whilst the iron reports to the solution. Factors which affect the rate and efficiency of reduction are examined. The reaction is rapid on fresh surfaces of chalcopyrite but slows markedly as a film of chalcocite or bornite forms. The reduction in the presence of copper metal goes to completion and gives a material which is more readily leached by oxidising agents than is chalcopyrite. Thus 99% of the copper in the reduced chalcopyrite is leached when copper(II) sulfate in aqueous acetonitrile is the oxidising agent, whereas only 30% of the copper is leached from pure chalcopyrite under similar conditions. Concentrated solutions of copper(I) salts are less effective in reducing CuFeS 2 in a heterogeneous solid-liquid reaction than is copper metal in a “galvanic” solid-solid reaction. Solutions of copper(II) sulfate plus concentrated copper(I) sulfate in dilute acetonitrile (4 M) containing copper sheets are an effective reductant for chalcopyrite.

Complexes of copper(II) with substituted hydrazines

The reactions of ethanolic solutions of copper(II) salts with substituted hydrazines yield green coloured crystalline compounds of the general composition Cu L 2 X 2, where L = hydrazine, phenylhydrazine, N, N′-dimethylhydrazine and N,N-diphenylhydrazine, and X = Cl, Br, I, SCN, NO 3, CH 3, COO and 0.5 SO 4. The structure of these complexes were examined by conventional techniques. The compounds have normal magnetic moment at room temperature. The electronic spectral analysis show them to be tetragonally distorted octahedral, approaching almost to squareplanar geometry in some disubstituted hydrazine complexes. The complexes appear to be polymeric containing hydrazine as a bidentate bridging ligand.

Influence of copper(II) salts on the solubility of caffeine in water: complex formation and the salting-out effect

Saturation curves of caffeine monohydrate cf·H2O and of several complex compounds in the systems H2O–Cu[NO3]2–cf (I) and H2O–CuCl2–cf (II) have been determined at various temperatures. Solubility curves of cf·H2O in solutions of Cu[ClO4]2(III) and Cu[SO4](IV) have also been examined. A regular variation in behaviour of the four systems is observed. A model is proposed and empirical expressions for (I) and (II) are calculated which take into account two different factors affecting the solublization of caffeine by dilute solutions of copper(II) salts, i.e. complex-formation equilibria and the salting-out effect. A qualitatively very good agreement between the model and the experimental data is found. Thermodynamic quantities are also calculated.

Solvation of ions. Some applications. III. Solutions of copper(I) salts in water containing ligands

Solutions of copper(II) and copper(I) sulphate in water containing acetonitrile have applications in the hydrometallurgy of copper. The potentials (n.h.e.) of the Cu+/Cu; the Pt/Cu2+, Cu+, and the Cu2+/Cu electrodes in water containing a large molar excess of various copper(I) bases and various counter-anions have been measured. Free energies of transfer of copper(I) ions from water to water containing the bases are calculated. ΔGtr(Cu+) at 25�C becomes less exoenergetic for water containing the bases in the following order: CN- >> S2O32- > Me2NCHS > KI > NH3 > C5H5N > KBr > KCl > C3H5OH ≥ MeCN, CO, C2H4 > C3H6. The reduction potentials of CuSO4/Cu2SO4 in acidic saturated copper(II) sulphate solutions and a range of Cu2SO4 concentrations in acetonitrile- water mixtures show that CuSO4/MeCN/H2O is a powerful oxidant, comparable in strength to acidic iron(III) sulphate in water. Acetonitrile is the preferred base for the processing of copper by way of solutions of copper(I) sulphate.

The Effects of Copper in Heated Nebulizers

The antibacterial potential of copper mesh in heated nebulizers was evaluated by simulating clnical usage in the laboratory and comparing the relationship between the copper levels achieved in nebulizer water and the growth of Pseudomonas aeruginosa organisms. Mesh size, length of immersion, temperature, water replacement, and nebulization all affected copper concentration. Antibacterial acitivity was demonstrated over a wide range of copper levels for as long as three weeks. Nebulizers driven for one hour by 10 L/min of gas flow and containing 8 gm of copper mesh were inoculated with more than 31,000 organisms and became sterile within 60 minutes of inoculation. Units without copper showed a much slower decline in colony counts. Solutions of copper salts also proved to be effective antibacterial substances but only in much higher concentrations than those achieved with copper mesh. It it is concluded that metallic copper mesh is an effective antibacterial substance when used in water-containing heated nebulizers. Attempts to quantitate aerosolization of copper were not sucessful, and potential upper-airway deposition and human toxicity with this technique remain to be defined.

ChemInform Abstract: THE TRIPLE COMPLEXES OF COPPER AND ITS COMPLEXES WITH THE SCHIFF BASES OF PYRIDINE‐2‐ALDEHYDE OR 2‐ACETYL PYRIDINE WITH ALIPHATIC DIAMINES

AbstractDie Komplexbildung zwischen Cu(II)‐Salzen und Pyridin‐2‐aldehyd oder 2‐Acetylpyridin und ogw‐Alkylendiaminen (n: 2, 3) in alkoholischer Lösung abhängig vom pH‐Wert und den Reaktantenkonzentrationen wird untersucht.

Magnetic and Optical Studies of Copper Caprylate in Dioxane-Ethanol Mixtures

The IR spectrum of copper caprylate exhibits only one absorption band at about 1580 cm-1 which has been assigned to the binuclear configuration of copper soaps. The magnetic and spectroscopic studies confirm that the binuclear structure of copper caprylate persists in solutions. The absorption band near 375 mµ reveals the presence of coppercopper linkage and thus establishes the binuclear configuration of copper soaps in mixed solvents. The behaviour of copper soap and copper salt solutions is quite different and the absorption maxima are observed at different wavelengths.

The Triple Complexes of Copper and its Complexes with the Schiff Bases of Pyridine‐2‐Aldehyde or 2‐Acetyl Pyridine with Aliphatic Diamines

AbstractWhen alcohol solutions of copper salts are mixed with pyridine‐2‐aldehyde (PyA) and aliphatic diamines (A) (either ethylene diamine or 1,3‐propane diamine) at pH ≤ 6.5, a copper complex containing a molecule of the pyridine derivative and a molecule of the diamine is formed, or a complex containing an additional molecule of the pyridine aldehyde is formed, depending on the PyA concentration in the solution. When the molar concentrations are Cu2+: 2PyA: A, and the pH ≥ 10, the copper (II) ion is reduced to monovalent copper, and a Schiff base of the copper complex is formed. When alcoholic solutions of copper, 2‐acetylpyridine (AcPy), and aliphatic diamines are mixed in concentration ratios of Cu2+: 2AcPy: A, and pH > 9.5, again, the copper ion is reduced and a Schiff base is obtained. At pH = 7.5 a triple complex is obtained only from the copper chloride, containing either or one or two molecules of acetylpyridine, depending on the concentration of the latter in the solution.

ADSORPTION BEHAVIOR OF COPPER (II) IONS BY SILK YARNS ON CUPRIC SALT TREATMENTS, WITH REFERENCE TO ITS INHIBITORY EFFECT ON PHOTODEGRADATION

Cu++ adsorption on domestic and erie silk spun yarns was treated by copper (II) and its effect on their photodegradation was examined.The spun silk yarns, when treated by the cupric salt solutions, adsorb Cu++ ions about to 0.5% of the weight of fiber in the case of the domestic silk, and about to 1.0% in the case of the erie silk, though the adsorbed amounts of Cu++ ions differ to some extent by the treating conditions.Generally, the adsorbed amount of Cu++ ions in the silk yarns increases with increasing temperature and pH of the cupric salt solutions. The elevation of temperatue causes the increase in the primary adsorption. The effect of the temperature is larger in the erie silk than in the domestic silk. The adsorption amount of Cu++ ions increases with increased in alkali concentration in the copper salt solution. Especially NH4OH addition increases not only the adsorption amount but also Cu++ bonding strength owing to the formation of ammine complex. Steeping of the spun yarns into a NH4OH solution after the copper (II) treatments also increases the adsorbed amount and bonding strength of Cu++ ions, this is also due to the formation of ammine complex.The fixed Cu++ ions in the treated silk yarns show an inhibitory effect on the photodegradation. When the deterioration is tested by Fade meter irradiation for 80 hours, the decrease in the strength and elongation of the Cu++-treated domestic silk was less by above 30% than that of untreated one but in the case of the treated erie silk this inhibitory effect was smaller than in the case of domestic silk.

Reactions of some N,N,N′,N′-tetraalkyl-substituted diamines with concentrated aqueous solutions of copper(II) salts

Reactions of some N,N,N′,N′-tetraalkyl-substituted diamines with concentrated aqueous solutions of copper(II) salts

Amperometric determination of chromium (III) in the presence of chromate, using ethylendiaminetetraacetic acid

1. The formation of less inert complexes of chromium (III) with acetate or bicarbonate ions substantially accelerates the complex formation of chromium with EDTA, which permits an amperometric determination of chromium in the titration of an excess of the reagent with a solution of copper salt. TABLE 2. Determination of Chromium (III) in the Pres-ence of Chromate (n=3; α=0.95). RatioCr3+/Cr (VI) Amount of Cr3+, mg. taken found taken found taken found 1:0 1,14 1,15±0,06 1,71 1,72±0,09 3,50 3,48±0,07 1:50 1,71 1,72±0,04 2,86 2,86±0,08 3,50 3,50±0,04 1:100 1,71 1,69±0,05 2,86 2,85±0,04 3,50 3,52±0,10 2. The method permits the determination of 1–3 mg chromium (III) in 10 ml of a solution with an error of less than 1%. The determination is not hindered by hundredfold amounts of chromate.

Spectrophotometric studies of copper (II)—bis-2-pyridyl glycol complex

An aqueous solution ofbis-2-pyridyl glycol forms a deep blue water-soluble complex with an aqueous solution of copper (II) salts. The complex has an absorption maximum at 600–650 mµ between pH range 3·0–8·7. The complex is stable for four days and obeys Lambert-Beer’s law in the concentration range of 5·08–50·80 ppm. of copper (II) in solution. The optical density of the complex remains constant between pH 3·8–5·9. The molar composition as determined by the method of continuous variation and by the slope ratio method has been found to be 1:1. The limits of interference due to some foreign ions during the estimation of copper (II) have been determined.

Paramagnetic relaxation in solutions of chromium, titanium, and copper salts

Paramagnetic relaxation in solutions of chromium, titanium, and copper salts

Mechanism and kinetics of catalytic oxidation of ethylene in contact with aqueous solutions of palladium and copper salts

Mechanism and kinetics of catalytic oxidation of ethylene in contact with aqueous solutions of palladium and copper salts

The infrared determination of the composition of stearic acid multilayers deposited from salt substrata of varying pH

Infrared techniques were used to determine the effect of pH on the composition of stearic acid films on substrates containing dilute solutions of lead, copper, aluminum, calcium, barium, sodium, and quaternary ammonium salts. It was found that the pH region at which interaction of salts with the film occurs is characteristic for the particular salt and narrower than previously generally reported.

Monochromatic filter for 5461 Å green

a simple method of making a large inexpensive monochromatic filter to isolate the 5461 A mercury green line is given. The filter consists of a glass cell of suitable thickness filled with a solution of didymium, copper and potassium salts in proper proportions.