Gold-rhenium compounds

Propylene oxide is also produced in Hquid-phase homogeneous oxidation reactions using various molybdenum-containing catalysts (209,210), cuprous oxide (211), rhenium compounds (212), or an organomonovalent gold(I) complex (213). Whereas gas-phase oxidation of propylene on silver catalysts results primarily in propylene oxide, water, and carbon dioxide as products, the Hquid-phase oxidation of propylene results in an array of oxidation products, such as propylene oxide, acrolein, propylene glycol, acetone, acetaldehyde, and others. 

Phillips and Timms [599] described a less general method. They converted germanium and silicon in alloys into hydrides and further into chlorides by contact with gold trichloride. They performed GC on a column packed with 13% of silicone 702 on Celite with the use of a gas-density balance for detection. Juvet and Fischer [600] developed a special reactor coupled directly to the chromatographic column, in which they fluorinated metals in alloys, carbides, oxides, sulphides and salts. In these samples, they determined quantitatively uranium, sulphur, selenium, technetium, tungsten, molybdenum, rhenium, silicon, boron, osmium, vanadium, iridium and platinum as fluorides. They performed the analysis on a PTFE column packed with 15% of Kel-F oil No. 10 on Chromosorb T. Prior to analysis the column was conditioned with fluorine and chlorine trifluoride in order to remove moisture and reactive organic compounds. The thermal conductivity detector was equipped with nickel-coated filaments resistant to corrosion with metal fluorides. Fig. 5.34 illustrates the analysis of tungsten, rhenium and osmium fluorides by this method. 

Other metal complexes of titanium, zirconium, vanadium, chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver and gold to synthesize a wide variety of interesting new compounds. It utilizes Hoffmann s [51] isolobal relationship between the C=C bond and the metal-carbon triple bond. 

Humans have at all times made use of the components of the earth s crust. As a consequence of the discovery that even rare materials may have technically interesting properties, there has been a drive to widen the exploitation of natural resources. New separation methods have made the extraction of desirable elements possible. Such rare elements are often obtained as by-products of the mining of common ores. Gold and platinum, for instance, are present in the anode sludge from electrolytic copper refining. The mineral molybdenite, a sulfide, is roasted at 800°C to the oxide from which molybdenum metal and its alloys are produced. During the roasting process the oxide of a rare element, rhenium, volatilizes and its compounds can be extracted from the gas phase as a by-product. Several examples of this type are treated in the different element chapters of this book. 

Iron and gold are coupled together in the compound [(Ph3p)2N][Fe3(CO)9(/i -PMeX/i "P)]2Au and rhenium is partnered with either rhodium or iridium by Haupt et... 

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