Cuprous components

Early catalysts for acrolein synthesis were based on cuprous oxide and other heavy metal oxides deposited on inert siHca or alumina supports (39). Later, catalysts more selective for the oxidation of propylene to acrolein and acrolein to acryHc acid were prepared from bismuth, cobalt, kon, nickel, tin salts, and molybdic, molybdic phosphoric, and molybdic siHcic acids. Preferred second-stage catalysts generally are complex oxides containing molybdenum and vanadium. Other components, such as tungsten, copper, tellurium, and arsenic oxides, have been incorporated to increase low temperature activity and productivity (39,45,46). 

Diol Components. Ethylene glycol (ethane 1,2-diol) is made from ethylene by direct air oxidation to ethylene oxide and ring opening with water to give 1,2-diol (40) (see Glycols). Butane-1,4-diol is stiU made by the Reppe process acetylene reacts with formaldehyde in the presence of catalyst to give 2-butyne-l,4-diol which is hydrogenated to butanediol (see Acetylene-DERIVED chemicals). The ethynylation step depends on a special cuprous... 

The principal components of the cut are butene-1, butene-2, isobutylene and butadiene-1,3. Methyl, ethyl, and vinyl acetylenes, butane and butadiene-1,2 are present in small quantities. Butadiene is recovered from the C4 fraction by extraction with cuprous ammonium acetate (CAA) solution, or by extractive distillation with aqueous acetonitrile (ACN). The former process is a liquid-liquid separation, and the latter a vapor-liquid separation. Both take advantage of differences in structure and reactivity of the various C4 components to bring about the desired separation. 

Its addn at a level of 0.1—5.0% was found to improve the octane rating of diesel fuels (Ref 10) Cuprous Chloride Complex. For prepn see above. It is a red cryst solid, readily decompd into its components at 135—40° (Refs 4 13). X-ray diffraction showed that the azomethane mols lie betw the infinite folded sheets of the Cu(I) chloride (Ref 11). The complex is used in the prepn of highly pure samples of azomethane (Ref 7)... 

From the first of the two reactions shown, it can be seen that in the acid cleaning solution the cupric ion (Cu2+) is formed from cupric oxide. The thiourea component then reduces the cupric ion to the cuprous ion (Cu+) and, in a series of reactions, complexes it, essentially preventing the cupric ion from ultimately plating out as copper. 

Most corrosion processes in copper and copper alloys generally start at the surface layer of the metal or alloy. When exposed to the atmosphere at ambient temperature, the surface reacts with oxygen, water, carbon dioxide, and air pollutants in buried objects the surface layer reacts with the components of the soil and with soil pollutants. In either case it gradually acquires a more or less thick patina under which the metallic core of an object may remain substantially unchanged. At particular sites, however, the corrosion processes may penetrate beyond the surface, and buried objects in particular may become severely corroded. At times, only extremely small remains of the original metal or alloy may be left underneath the corrosion layers. Very small amounts of active ions in the soil, such as chloride and nitrate under moist conditions, for example, may result, first in the corrosion of the surface layer and eventually, of the entire object. The process usually starts when surface atoms of the metal react with, say, chloride ions in the groundwater and form compounds of copper and chlorine, mainly cuprous chloride, cupric chloride, and/or hydrated cupric chloride. 

FIGURE 41 Bronze disease. Bronze disease, one of the most serious corrosive processes besetting recovered bronze antiquities, results from the interaction of one component of the patina on ancient bronze, namely, cuprous chloride with atmospheric oxygen, in a damp environment. Small spots of a light green powder (composed mainly of cuprous chloride) that grow rapidly on the surface of the patina are indicative that the bronze disease process is active. Unless the chemical activity of cuprous chloride is inhibited by some conservation procedure, bronze disease generally results in the eventual total destruction of bronze objects. 

Recently, Batthyany et al. [133] pointed out that the reduction of cupric ions bound to apolipoprotein B-100 by endogenous LDL components might be an initiation step in copper-mediated LDL oxidation. They suggested that this reaction proceeds to form cuprous ion and the protein-tryptophanyl free radical the latter was identified on the basis of EPR spectrum with spin-trap 2-methyl-2-nitrosopropane. 

It would be possible to consider chloride as a type 1 component in this system so that the diagram could reveal areas in which Cl2(gas), Cl, CIO3 and CIO4 predominated. However, to do so here would obscure the question of how to deal with the various chloride complexes of cuprous and cupric ions, which is the principle concern of this section. 

Cuprous acetylide is used as the chief component of match heads in electric fuses, being particularly susceptible to ignition by sparks or a glowing wire to give a sharp, hot flame. 

In a large variety of detonators, in which LA has been loaded into brass containers, cuprous azide is formed on the surface of containers stored under hot and humid con ditions. Extreme care should be exercised in handling cuprous azide or any components of ammunition in which it may be formed... 

Cupric oxide dissociates into cuprous oxide and oxygen. Two independent components, cuprous oxide and oxygen, form the system, which] bdow a certain temperature is divided among three phases, solid cupric oxide, solid cuprous oxide, oxygen gas. The system is monovariant, admitting a curve of dissociation tensions. 

---