Oxidation metal peroxides

The second catalyst paste of the two-paste product is a curing agent. A wide variety of materials convert the Hquid polysulfide polymers to elastomeric products. Alkalies, sulfur, metallic oxides, metallic peroxides, organic peroxides, and many metal—organic salts, ie, paint driers, are all potential curing agents. 

Keywords Sulfur ylides, Carbenes, Betaines, Polyamino acids. Nucleophilic oxidation. Metal peroxides, Epoxidation... 

Magnesium Air, beryllium fluoride, ethylene oxide, halogens, halocarbons, HI, metal cyanides, metal oxides, metal oxosalts, methanol, oxidants, peroxides, sulfur, tellurium... 

Inorganic Methods. Before the development of electrolytic processes, hydrogen peroxide was manufactured solely from metal peroxides. Eady methods based on barium peroxide, obtained by air-roasting barium oxide, used dilute sulfuric or phosphoric acid to form hydrogen peroxide in 3—8% concentration and the corresponding insoluble barium salt. Mote recent patents propose acidification with carbon dioxide and calcination of the by-product barium carbonate to the oxide for recycle. 

Berzehus (19) further appHed and amplified the nomenclature introduced by Guyton de Morveau and Lavoisier. It was he who divided the elements into metalloids (nonmetals) and metals according to their electrochemical character, and the compounds of oxygen with positive elements (metals) into suboxides, oxides, and peroxides. His division of the acids according to degree of oxidation has been Httie altered. He introduced the terms anhydride and amphoteric and designated the chlorides in a manner similar to that used for the oxides. 

Alkali metal peroxides are stable under ambient conditions in the absence of water. They dissolve vigorously in water, forming hydrogen peroxide and the metal hydroxide. They are strong oxidizing agents and can react violendy with organic substances. Only lithium peroxide and sodium peroxide have been commercialized. 

Etch Mechanisms. Most wet etches for the compound semiconductors employ oxidation of the semiconductor followed by dissolution of the oxide. For this reason, many wet etches contain the oxidant hydrogen peroxide, although nitric acid can also be used. One advantage of wet etching over dry is the absence of subsurface damage that is common with dry etching. Metal contacts placed on wet-etched surfaces exhibit more ideal characteristics than dry-etched surfaces. 

The Hquid polymer is then compounded with metal oxides or peroxides, as weU as fillers (carbon black) and can undergo cold vulcanization, ie, chain extension and cross-linking iato a soHd matrix. It is largely used as a sealant and gasket material for wiadows, automobile wiadshields, etc. 

In addition to the oxides MO, peroxides MO2 are known for the heavier alkaline earth metals and there is some evidence for yellow superoxides M(02)2 of Ca, Sr and Ba impure ozonides Ca(03)2 and Ba(03)2 have also been reported. As with the alkali metals, stability... 

Adam and Lohray122 have used thianthrene 5-oxide (88) as a mechanistic probe in oxidations with transition metal peroxides. They oxidized 88 with various diperoxo complexes of chromium, molybdenum and tungsten and formulated a plausible mechanism on the basis of the products formed, 89 and 90. 

Hydrogen sulfide is rapidly oxidised, and may ignite in contact with a range of metal oxides, including barium peroxide, chromium trioxide, copper oxide, lead dioxide, manganese dioxide, nickel oxide, silver(I) oxide, silver(II) oxide, sodium peroxide, and thallium(III) oxide. In the presence of air, contact with mixtures of calcium oxide or barium oxide with mercury oxide or nickel oxide may cause vivid incandescence or explosion. 

See related METAL peroxides See other METAL OXIDES, OXIDANTS 4657. Potassium trioxide (Potassium ozonide)... 

See related metal peroxides See other METAL oxides... 

Iodine pentafluoride Metals Lead(IV) oxide Metals Nitryl fluoride Metals Potassium perchlorate Metal powders Sodium peroxide Metals See other metals... 

Metal oxides or peroxides MRH values below references... 

Hydrogen peroxide Metals, Metal oxides, Metal salts Hydrogen sulfide Oxidants... 

The UV/Vis, Mossbauer, EXAFS, and EPR spectroscopic data suggest a rather complicated picture regarding the speciation of oxidized TAML species derived from 1 and various oxidants in aqueous solution (Scheme 5). Peroxides ROOH have the capacity to function as two-electron oxidants and usually do. In cases where prior coordination occurs, they can oxidize metal ions via one-electron processes where the 0-0 bond is cleaved homo-lytically or two-electron processes where it is cleaved hetero-lytically. The two-electron oxidation of 1 presumably would give the iron-oxo intermediate 6, two electrons oxidized above the iron(III) state (see below). Before 6 was actually isolated, there... 

Two basic methods have been used to grow metal oxide thin films by the SILAR technique (see Table 8.1). The more common of these methods consists of the adsorption of metal hydroxide ions on the substrate surface followed by thermal treatment to convert hydroxide to an oxide. Another way to produce metal oxide films is to use hydrogen peroxide as the anion precursor and then to convert the formed metal peroxide film to an oxide film. Several examples of each approach are discussed in more detail below. 

Copper(II) sulfate Cumene hydroperoxide Cyanides Cyclohexanol Cyclohexanone Decaborane-14 Diazomethane 1,1-Dichloroethylene Dimethylformamide Hydroxylamine, magnesium Acids (inorganic or organic) Acids, water or steam, fluorine, magnesium, nitric acid and nitrates, nitrites Oxidants Hydrogen peroxide, nitric acid Dimethyl sulfoxide, ethers, halocarbons Alkali metals, calcium sulfate Air, chlorotrifluoroethylene, ozone, perchloryl fluoride Halocarbons, inorganic and organic nitrates, bromine, chromium(VI) oxide, aluminum trimethyl, phosphorus trioxide... 

Metal oxide sensors (MOS), smart, 22 717 Metal oxide supported catalysts, 5 336-337 coke formation on, 5 267—270 Metal passivation, in industrial water treatment, 26 137 Metal peroxides, 18 410 Metal phosphates, tertiary, 18 840 Metal-phosphorus alloys, 19 59 Metal phthalocyanines, electrochromic materials, 6 572t, 576-577 Metal prefinishing, detersive systems for, 8 413t... 

Acting on hydrogen peroxide as accep- 1.16 Oxidizing metal ions... 

Palladium and platinum. These are resistant to chemical attack (Pt more than Pd). Both metals dissolve in fused alkali metal oxides and peroxides. Pt is attacked, at high temperature, by molten alkali and alkaline earth halogenides and by several compounds of B, Si, Pb, P, As, Sb, Bi. Pd dissolves slowly in oxidizing acids Pt is dissolved by aqua regia. 

This group contains many powerful oxidants, the most common being sodium peroxide. Undoubtedly one of the most hazardous is potassium dioxide or superoxide, readily formed on exposure of the metal to air (but as the monovalent O2 ion it is not a true peroxide). Many transition metal peroxides are dangerously explosive. Individually indexed peroxides are ... 

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