Cupric peroxide

It has been concluded from a study of the optical and e.p.r. spectra of Co —Cu bovine superoxide dismutase, in which zinc has been replaced by cobalt, that the cobalt site reactivity should be described in terms of reaction of the Co-imidazolate-Cu system as a whole the crystal structure reported last year indicated that the metals were linked by a common histidine residue. There is an exchange interaction between the cobalt and copper however, this is abolished when the linking imidazole is protonated. Further evidence for the close proximity and interactive dependence of the zinc and copper binding sites was obtained from a study of the 4 Cu protein a two-fold enhancement of the activity of 2 Cu dismutase was observed upon occupation of the zinc sites by the Cu ". On the basis of C1 n.m.r. studies, Fee and Ward have suggested that one co-ordination position of Cu in superoxide dismutase is normally occupied by water they further suggest that superoxide can displace the solvent to form a cupric peroxide complex. 

The mechanism and rate of hydrogen peroxide decomposition depend on many factors, including temperature, pH, presence or absence of a catalyst (7—10), such as metal ions, oxides, and hydroxides etc. Some common metal ions that actively support homogeneous catalysis of the decomposition include ferrous, ferric, cuprous, cupric, chromate, dichromate, molybdate, tungstate, and vanadate. For combinations, such as iron and... 

The hberated iodine, as the complex triiodide ion, may be titrated with standard thiosulfate solution. A general iodometric assay method for organic peroxides has been pubUshed (253). Some peroxyesters may be determined by ferric ion-catalyzed iodometric analysis or by cupric ion catalysis. The latter has become an ASTM Standard procedure (254). Other reducing agents are ferrous, titanous, chromous, staimous, and arsenite ions triphenylphosphine diphenyl sulfide and triphenjiarsine (255,256). 

The most suitable oxidizing agent is potassium ferricyanide, but ferric chloride, hydrogen peroxide ia the presence of ferrous salts, ammonium persulfate, lead dioxide, lead tetraacetate or chromate, or silver and cupric salts may be useful. Water mixed, eg, with methanol, dimethylformamide, or glycol ethers, is employed as reaction medium. 

Copper etchants do not directly influence the electroless plating process, but are used merely to remove unwanted copper, and should not affect the deposit properties. The costs of waste treatment and disposal have led to disuse of throw-away systems such as chromic—sulfuric acid, ferric chloride, and ammonium persulfate. Newer types of regenerable etchants include cupric chloride, stabilized peroxide, and proprietary ammoniacal etchant baths. 

Aluminium nitrate Ammonium persulphate Barium nitrate/peroxide Calcium nitrate/peroxide Cupric nitrate... 

In chemically-cured materials, one example of an initiator/activator system is hydrogen peroxide as initiator, ascorbic acid as activator and cupric sulphate as co-activator. In light-cured materials, camphorquinone is used as a visible-light photochemical initiator, sodium p-toluene-sulphinate as activator and ethyl 4-dimethylaminobenzoate as photoaccelerator. 

Dizdaroglu, M., Rao, G., Halliwell, B. and Gajewski, E. (1991a). Damage to the DNA bases in mammalian chromatin by hydrogen peroxide in the presence of ferric and cupric ions. Arch. Biochem. Biophys. 285, 317-324. 

In the manufacture of printed circuit boards, the unwanted copper is etched away by acid solutions of cupric chloride (Equation 1.1). As the copper dissolves, the effectiveness of the solution tails and it must be regenerated. The traditional way of doing this is to oxidize the cuprous ion produced with acidified hydrogen peroxide. During the process the volume of solution increases steadily and the copper in the surplus liquor is precipitated as copper oxide and usually landfilled. 

In contrast to numerous literature data, which indicate that protein oxidation, as a rule, precedes lipid peroxidation, Parinandi et al. [66] found that the modification of proteins in rat myocardial membranes exposed to prooxidants (ferrous ion/ascorbate, cupric ion/tert-butyl-hydroperoxide, linoleic acid hydroperoxide, and soybean lipoxygenase) accompanied lipid peroxidation initiated by these prooxidant systems. 

Other examples of interfering substances are oxidizing agents such.as peroxides, cupric... 

Among the oxidative procedures for preparing azo compounds are oxidation of aromatic amines with activated manganese dioxide oxidation of fluorinated aromatic amines with sodium hypochlorite oxidation of aromatic amines with peracids in the presence of cupric ions oxidation of hindered aliphatic amines with iodine pentafluoride oxidation of both aromatic and aliphatic hydrazine derivatives with a variety of reagents such as hydrogen peroxide, halogens or hypochlorites, mercuric oxide, A-bromosuccinimide, nitric acid, and oxides of nitrogen. 

---