The State of Copper

The State of Copper in Ceruloplasmin. The early room temperature 

Since it is well known that at least part of the Cu of ceruloplasmin undergoes cyclic reduction by substrate and oxidation by molecular oxygen (88), the availability of the various Cu binding sites to small solute molecules is of importance. One of the first observations which suggested that at least part of the Cu was 

Andreasson and Vdnng rd (179) have presented convincing evidence that azide ion binds to Type 2 Cu2+, and they have suggested that this effects inhibition of oxidase activity. Results concerned with the relation between ion binding and 

A number of studies have dealt with the binding of anions to ceruloplasmin. Kasper 144) demonstrated that azide, cyanide, thiocyanate, and cyanate at fairly high concentrations produced spectral alterations of ceruloplasmin by liganding a portion of the Cu. He also found that approximately 12% of the total Cu could be removed irreversibly by 0.1 M KCN with only a 50% loss in oxidase activity. Byers et at. (72) have carried out an extensive study of the binding of several anions to the oxidized form of ceruloplasmin. Their results suggest the presence of two binding sites for azide and thiocyanate, with the stability constant of the second being approximately 100-fold less than the first. The authors have interpreted their data in terms of anation of the Type 3 Cu atoms for all anions except F which binds to the Type 2 Cu +. 

If all the assumptions which have been made in the interpretation of the above described perturbation experiments are correct, dl Types of Cu are accessible to perturbants this seems very unlikely. 

---

Malmstrom, B.G., Mosbach, R., and Vanngard, T. 1959. An electron spin resonance study of the state of copper in fungal laccase. Nature 183 321-322. 

Neumann, P. Z., Sass-Kortsak, I., The State of Copper in Human Serum ... 

The data on the state of copper-containing phases and acid—base properties of active sites occurring at the surface of mixed cement systems, which were presented above, enable us to conclude that these catalysts can be employed in the oxidative ehlorination of ethane. 

Studies on the State of Copper anc the Formation of its Oxidic and Metallic Phases in Zeolite CuNaY... 

Based on the above mentioned data the paper shows the results of research performed for a Cu-ZSM-5 catalyst production to the purpose of purification of vehicle engines exhaust gases. The influence of the ion exchange level in ZSM-5 upon the catalytic performances is also studied. The catalysts used were Cu-ZSM-5 granules or Cu-ZSM-5 coating on a ceramic monolith. The trials of correlation between the catalysts performances and the state of copper in catalysts prepared is also showed. 

The state of copper in the prepared catalysts was studied by ESR spectroscopic technique and by thermal analysis in flow hydrogen medium. Experimental measurements were performed with a spectrometer ART-6 in X frequency bands analysis (u = 9010 MHz) and a thermoanalitical instrument SETARAM. 

The main changes in the chemical bonding take place in Cu-0 chains. The results in Table 9.3 show that the charge state of Cu I atoms (in Cu-0 chains) in YBa2Cus06 crystal is close to the state of copper atoms in Cu I oxides, but that in YBa2Cus07 they are close to copper atoms in Cu III oxides. 

Y. Kuroda, T. Mori, Y. Yoshikawa, S. Kittaba, R. Kumashiro, M. Nagao, What are the important factors determining the state of copper ion on various supports Antilysis using spectroscopic methods and adsorption calorimetry. Phys. Chem. Chem. Phys. 1,3807-3816 (1999). doi 10. 1039/A9047541... 

Chlorine reacts with most elements, both metals and non-metals except carbon, oxygen and nitrogen, forming chlorides. Sometimes the reaction is catalysed by a trace of water (such as in the case of copper and zinc). If the element attacked exhibits several oxidation states, chlorine, like fluorine, forms compounds of high oxidation state, for example iron forms iron(III) chloride and tin forms tin(IV) chloride. Phosphorus, however, forms first the trichloride, PCI3, and (if excess chlorine is present) the pentachloride PCI5. 

Even ia 1960 a catalytic route was considered the answer to the pollution problem and the by-product sulfate, but nearly ten years elapsed before a process was developed that could be used commercially. Some of the eadier attempts iacluded hydrolysis of acrylonitrile on a sulfonic acid ion-exchange resia (69). Manganese dioxide showed some catalytic activity (70), and copper ions present ia two different valence states were described as catalyticaHy active (71), but copper metal by itself was not active. A variety of catalysts, such as Umshibara or I Jllmann copper and nickel, were used for the hydrolysis of aromatic nitriles, but aUphatic nitriles did not react usiag these catalysts (72). Beginning ia 1971 a series of patents were issued to The Dow Chemical Company (73) describiag the use of copper metal catalysis. Full-scale production was achieved the same year. A solution of acrylonitrile ia water was passed over a fixed bed of copper catalyst at 85°C, which produced a solution of acrylamide ia water with very high conversions and selectivities to acrylamide. 

Copper [7440-50-8] Cu, critically important to the development of civilization, is the only common metal found naturally in the metallic state. It was thus suitable for the production of tools, and ancient people made use of its easy workabiUty and beauty. Furthermore, the ease with which the oxide can be reduced to the metal, together with the tendency of copper to alloy with other metals naturally present in the ores, promoted broad usage. 

The output from brass mills in the United States is spHt nearly equally between copper and the alloys of copper. Copper and dilute copper alloy wrought products are melted and processed from electrically refined copper so as to maintain low impurity content. Copper alloys are commonly made from either refined copper plus elemental additions or from recycled alloy scrap. Copper alloys can be readily manufactured from remelted scrap while maintaining low levels of nonalloy impurities. A greater proportion of the copper alloys used as engineering materials are recycled than are other commercial materials. 

Copper compounds, which represent only a small percentage of ah copper production, play key roles ia both iadustry and the biosphere. Copper [7440-50.8] mol wt = 63.546, [Ar]3/°4.t is a member of the first transition series and much of its chemistry is associated with the copper(II) ion [15158-11-9] [Ar]3i5. Copper forms compounds of commercial iaterest ia the +1 and +2 oxidation states. The standard reduction potentials, for the reasonably attainable valence states of copper are... 

The main by-products of the Ullmaim condensation are l-aniinoanthraquinone-2-sulfonic acid and l-amino-4-hydroxyanthraquinone-2-sulfonic acid. The choice of copper catalyst affects the selectivity of these by-products. Generally, metal copper powder or copper(I) salt catalyst has a greater reactivity than copper(Il) salts. However, they are likely to yield the reduced product (l-aniinoanthraquinone-2-sulfonic acid). The reaction mechanism has not been estabUshed. It is very difficult to clarify which oxidation state of copper functions as catalyst, since this reaction involves fast redox equiUbria where anthraquinone derivatives and copper compounds are concerned. Some evidence indicates that the catalyst is probably a copper(I) compound (28,29). 

The production of copper from sulphide minerals is accomplished with a preliminary partial roast of die sulphides before reaction widr air in the liquid state, known as mattes, to form copper metal (conversion). The principal sources of copper are minerals such as chalcopyrite, CuFeSa and bornite CuaFeSa, and hence the conversion process must accomplish the preferential oxidation of non, in the form of FeO, before the copper metal appears. As mentioned before, tire FeO-SiOa liquid system is practically Raoultian, and so it is relatively easy to calculate the amount of iron oxidation which can be canned out to form this liquid slag as a function of the FeO/SiOa ratio before copper oxidation occurs. The liquid slag has a maximum mole fraction of FeO at the matte blowing temperatures of about 0.3, at solid silica saturation. 

P.S. Follansbee and U.F. Kocks, A Constitutive Description of the Deformation of Copper Based on the Use of the Mechanical Threshold Stress as an Internal State Variable, Acta Metall. 36, 81-93 (1988). 

It is not certain whether Sir Humphrey Davy (Fig. 1-7) knew of these considerations. He accepted a commission from the Admiralty for the protection of copper-clad wooden ships, which had been introduced in 1761. During his numerous laboratory experiments, he discovered the cathodic protection of copper by zinc or iron [3]. Davy had already put forward the hypothesis in 1812 that chemical and electrical changes are identical or at least arise from the same material property. He believed that chemical reaction forces could be reduced or increased by altering the electric state of the material. Materials can combine only if they have different electric charges. If an originally positive material can be artificially negatively... 

When the radicals have p hydrogens, alkenes are formed by a process in which carbocations are probably bypassed. Instead, the oxidation and the elimination of a proton probably occur in a single step through an alkylcopper species. The oxidation state of copper in such an intermediate is Cu(III). 

Now look at the numerical values of the equilibrium constants. The K s listed range from 10+1 to 10 16, so we see there is a wide variation. We want to acquire a sense of the relation between the size of the equilibrium constant and the state of equilibrium. A large value of K must mean that at equilibrium there are much larger concentrations present of products than of reactants. Remember that the numerator of our equilibrium expression contains the concentrations of the products of the reaction. The value of 2 X 10,s for the K for reaction (19) certainly indicates that if a reaction is initiated by placing metallic copper in a solution containing Ag+ (for example, in silver nitrate solution), when equilibrium is finally reached, the concentration of Cu+2 ion, [Cu+2], is very much greater than the square of the silver ion concentration, [Ag+]2. 

What about the state of equilibrium for the reaction represented by equation (11)1 Let us place a strip of metallic copper in a zinc sulfate solution. No visible reaction occurs and attempts to detect the presence of cupric ion by adding H2S to produce the black color of cupric sulfide, CuS, fail. Cupric sulfide has such low solubility that this is an extremely sensitive test, yet the amount of Cu+2 formed cannot be detected. Apparently the state of equilibrium for the reaction (11) greatly favors the products over the reactants. 

---