Gold-molybdenum compounds

Minerals and Metals. HCl is consumed in many mining operations for ore treatment, extraction, separation, purification, and water treatment (see Mineral recovery and processing). Significant quantities are also used in the recovery ofmolybdenum (see Molybdenum and molybdenum alloys) and gold (see Gold and gold compounds). This market consumed about 36 thousand metric tons in 1993. 

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. 

Nonpolar molecular compounds dissolve in nonpolar solvents. Polar molecular compounds and ionic compounds may dissolve in polar solvents. Metals dissolve in other molten metals. These can range from copper, silver, gold, alkali metals dissolving in mercury at room temperature, to chromium, molybdenum, and tungsten dissolving in molten iron. 

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. 

Cr(II) may be used to carry out all the reactions of Ti(III), but usually under milder conditions. Applications of Cr(II) as a reductant have been reviewed. The applications include Sn(IV) chloride in the presence of catalysts such as Sb(V) or Bi(III), Sb(V) in 20% HCl at elevated temperatures, Cu(II), silver, gold, mercury, bismuth, iron, cobalt, molybdenum, tungsten, uranium, dichromate, vanadate, titanium, thallium, hydrogen peroxide, oxygen in water and gases, as well as organic compounds such as azo, nitro, and nitroso compounds and quinones. Excess Cr(II) in sulfuric acid solution reduces nitrate to ammonium ion. The reduction is catalyzed by Ti(IV), which is rapidly reduced to Ti(III). 

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