Oxygen reaction with copper

Oxychlorination of Ethylene to Dichloroethane. Ethylene (qv) is converted to dichloroethane in very high yield in fixed-bed, multitubular reactors and fluid-bed reactors by reaction with oxygen and hydrogen chloride over potassium-promoted copper(II) chloride supported on high surface area, porous alumina (84) ... 

The reaction of binuclear copper complexes with oxygen as models for tyrosinase activity was also markedly accelerated by applying pressure (106408 ). Tyrosinase is a dinuclear copper protein which catalyses the hydroxylation of phenols. This reaction was first successfully modeled by Karlin and co-workers (109), who found that an intramolecular hydroxylation occurred when the binuclear Cu(I) complex of XYL-H was treated with oxygen (Scheme 5). 

Terminal alkenes can be selectively oxidized to aldehydes by reaction with oxygen, using a palladium-copper catalyst in tertiary butanol (equation 35)160. This reaction is contrary to the normal oxidation process which yields a ketone as the major product. The palladium(II) oxidation of terminal alkenes to give methyl ketones is known as the Wacker process. It is a very well established reaction in both laboratory and industrial synthesis161162. The Wacker oxidation of alkenes has been used in the key step in the synthesis of the male sex pheromone of Hylotrupes bajulus (equation 36)163. 

Toluene was oxidized to a mixture of benzyl acetate (31) and benzylidene diacetate (32) on reaction with oxygen in the presence of a silica supported Pd-Sn catalyst.A reaction run in HOAc/KOAc at 70°C under an atmosphere of oxygen gave a near 3 1 ratio of the monoacetate to the diacetate at 98% conversion (Eqn. 21.40). The two products are formed in parallel reactions as the benzylacetate does not react further under these reaction conditions. Substituted diphenylmethanes were oxidized to the diphenyl ketones by refluxing them in air in a DMF solution containing a copper powder catalyst.""... 

Figure 20-4 Proposed function of ceruloplasmin copper (CpCu " ) as a proton (hydrogen ion) recipient from cellular ferrous iron.The resulting oxidation of Fe to the ferric state permits its binding and transport by plasma transferrin. CpCu" is oxidized (regenerated to CpCu ) by reaction with oxygen, oxidized thiol groups, or other oxidizing substances, (Modified from Johnson AM. Ceru/op/osm/n. In Ritchie RF, Navolotskaia 0, editors. Serum proteins in clinical medicine. Vol. I Laboratory section. Scarborough, ME Foundation for Blood Research, 1996 13.01-13.03.)...

The reaction of 1,1-dimethylhydrazine with dissolved oxygen in water may proceed by a process catalyzed by copper ions or by an uncatalyzed reaction (Baneijee et al. 1984). The products include dimethylnitrosamine, formaldehyde, dimethylamine, and other related chemicals. Dimethylnitrosamine did not form in dilute solutions, which might be encountered in ambient waters, but was reported in concentrated solutions, which could be present in the vicinity of spills (EPA 1984a). The reported half-life of 1,1-dimethylhydrazine in ponds and seawaters ranged from 10 to 14 days, presumably because of reaction with oxygen and other free radicals (EPA 1984a). 

The high redox potentials of copper proteins make them highly suitable for reactions with oxygen. In the course of evolution, six different types of copperbinding centers have evolved for catalyzing the various reactions and will be described in the following. 

Here, a copper atom loses two electrons just as it did in the reaction with oxygen - it is oxidized. Sulfur gains two electrons and is reduced. 

Galvanic Cell Formation When dissimilar metals are in contact in an electrolyte, a galvanic cell is established because of the electrochemical potential difference (24). The consequence of the galvanic cell is the corrosion of the less noble metal. For example, when copper is in contact with iron in the presence of an electrolyte, the iron anode will corrode to generated Fe " " ions, which on further reaction with oxygen forms brown iron oxide while oxygen reduction occurs at the copper cathode. The reactions are... 

Use the information about the reaction of copper sulfide with oxygen to answer the following questions ... 

The use of hydrazine is not subject to similar objections, but its slow reaction with oxygen and partial decomposition into NH3 should be taken into account in calculating proper dosages. Also, NH3 is a possible cause of stress-corrosion cracking of copper-base alloys in the condenser system, should oxygen accidentally contaminate the condensate. 

The reaction of alcohols and dioxygen in the presence of metal complexes often gives rise to aldehydes or ketones [307]. An early patent reports that methanol may be converted to formaldehyde in 80% yield by reaction with oxygen at 25 °C in the presence of copper-amine complexes [308]. Gas phase oxidation of 2-propanol to acetone and water was catalyzed by j3-Cu-phthalocyanine [309]. 

Applications of Radioactive Kryptonates [32], 92J. 94]-[96]. The determination of oxygen is performed by surface oxidation of copper or pyro-graphite kryptonate, at elevated temperature, resulting in destruction of the surface layer and release of Kt proportional to the oxygen mass. Detection limits are at the 10 ng/m level. Ozone oxidizes copper kryptonate at temperatures below 100 °C. whereas reaction with oxygen starts well above 200 °C, so this detector can detect Ox and O2 differentially. Determination of ozone in air is feasible over a concentration range of 10 - 10 g/m with hydroquinone kryptonate ... 

The reactions with oxygen, water, and hydrochloric add show that iron is more reactive than copper. Now look at this experiment ... 

Kau LS, Spira-Soloman DJ, Penner-Hahn JE, Hodgson KO, Solomon El. X-ray absorption edge determination of the oxidation state and coordination number of copper. Application to the type 3 site in Rhus vemicifera laccase and its reaction with oxygen. J Am Chem Soc 1987 109 6433-6442. 

Oxidation. Acetaldehyde is readily oxidised with oxygen or air to acetic acid, acetic anhydride, and peracetic acid (see Acetic acid and derivatives). The principal product depends on the reaction conditions. Acetic acid [64-19-7] may be produced commercially by the Hquid-phase oxidation of acetaldehyde at 65°C using cobalt or manganese acetate dissolved in acetic acid as a catalyst (34). Liquid-phase oxidation in the presence of mixed acetates of copper and cobalt yields acetic anhydride [108-24-7] (35). Peroxyacetic acid or a perester is beheved to be the precursor in both syntheses. There are two commercial processes for the production of peracetic acid [79-21 -0]. Low temperature oxidation of acetaldehyde in the presence of metal salts, ultraviolet irradiation, or osone yields acetaldehyde monoperacetate, which can be decomposed to peracetic acid and acetaldehyde (36). Peracetic acid can also be formed directiy by Hquid-phase oxidation at 5—50°C with a cobalt salt catalyst (37) (see Peroxides and peroxy compounds). Nitric acid oxidation of acetaldehyde yields glyoxal [107-22-2] (38,39). Oxidations of /)-xylene to terephthaHc acid [100-21-0] and of ethanol to acetic acid are activated by acetaldehyde (40,41). 

Reactions of the Hydroxyl Group. The hydroxyl proton of hydroxybenzaldehydes is acidic and reacts with alkahes to form salts. The lithium, sodium, potassium, and copper salts of sahcylaldehyde exist as chelates. The cobalt salt is the most simple oxygen-carrying synthetic chelate compound (33). The stabiUty constants of numerous sahcylaldehyde—metal ion coordination compounds have been measured (34). Both sahcylaldehyde and 4-hydroxybenzaldehyde are readily converted to the corresponding anisaldehyde by reaction with a methyl hahde, methyl sulfate (35—37), or methyl carbonate (38). The reaction shown produces -anisaldehyde [123-11-5] in 93.3% yield. Other ethers can also be made by the use of the appropriate reagent. 

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