Related metals

Today, the air oxidation of toluene is the source of most of the world s synthetic benzaldehyde. Both vapor- and Hquid-phase air oxidation processes have been used. In the vapor-phase process, a mixture of air and toluene vapor is passed over a catalyst consisting of the oxides of uranium, molybdenum, or related metals. High temperatures and short contact times are essential to maximize yields. Small amounts of copper oxide maybe added to the catalyst mixture to reduce formation of by-product maleic anhydride. [Pg.34]

In addition to platinum and related metals, the principal active component ia the multiflmctioaal systems is cerium oxide. Each catalytic coaverter coataias 50—100 g of finely divided ceria dispersed within the washcoat. Elucidatioa of the detailed behavior of cerium is difficult and compHcated by the presence of other additives, eg, lanthanum oxide, that perform related functions. Ceria acts as a stabilizer for the high surface area alumina, as a promoter of the water gas shift reaction, as an oxygen storage component, and as an enhancer of the NO reduction capability of rhodium. [Pg.370]

JS/oble Metals. Noble or precious metals, ie, Pt, Pd, Ag, and Au, are ftequendy alloyed with the closely related metals, Ru, Rh, Os, and Ir (see Platinum-GROUP metals). These are usually supported on a metal oxide such as a-alumina, a-Al202, or siUca, Si02. The most frequently used precious metal components are platinum [7440-06-4J, Pt, palladium [7440-05-3] Pd, and rhodium [7440-16-6] Rh. The precious metals are more commonly used because of the abiUty to operate at lower temperatures. As a general rule, platinum is more active for the oxidation of paraffinic hydrocarbons palladium is more active for the oxidation of unsaturated hydrocarbons and CO (19). [Pg.503]

A number of indices relate metal activity to hydrogen and coke production. (These indices predate the use of metal passivation in the FCC process but are still reliable). The most commonly used index is 4 X Nickel + Vanadium. This indicates that nickel is four times as actiw as vanadium in producing hydrogen. Other indices [9] used are ... [Pg.63]

Calcination is performed in crucibles made of platinum or related metals. Tantalum or niobium oxide can be successfully used in the manufacturing of such crucibles. Frolov et al. [505, 506] developed a method for coating various ceramic materials with tantalum or niobium oxide using an optical furnace. [Pg.301]

Two metals that are chemically related and that have atoms of nearly the same size form disordered alloys with each other. Silver and gold, both crystallizing with cubic closest-packing, have atoms of nearly equal size (radii 144.4 and 144.2 pm). They form solid solutions (mixed crystals) of arbitrary composition in which the silver and the gold atoms randomly occupy the positions of the sphere packing. Related metals, especially from the same group of the periodic table, generally form solid solutions which have any composition if their atomic radii do not differ by more than approximately 15% for example Mo +W, K + Rb, K + Cs, but not Na + Cs. If the elements are less similar, there may be a limited miscibility as in the case of, for example, Zn in Cu (amount-of-substance fraction of Zn maximally 38.4%) and Cu in Zn (maximally 2.3% Cu) copper and zinc additionally form intermetallic compounds (cf. Section 15.4). [Pg.157]

See related METAL PERCHLORATES, N-S COMPOUNDS See other silver compounds... [Pg.21]

See related metal azides See other high-nitrogen compounds... [Pg.54]

Preparative hazard See Bromine Germane See related METAL HYDRIDES... [Pg.105]

See related METAL CYANIDES (AND CYANO COMPLEXES) See other SILVER COMPOUNDS... [Pg.128]

See other static initiation incidents See related metal perchlorates... [Pg.177]

See Sodium nitrite Potassium thiocyanate See related metal cyanides... [Pg.228]

See related metal oxalates See other platinum compounds... [Pg.367]

See related metal azotetrazolides See other iv-oxides, tetrazoles... [Pg.374]

See other GOLD COMPOUNDS See related METAL CYANATES... [Pg.431]

See related METAL PERCHLORATES See other MERCURY COMPOUNDS... [Pg.482]

See related metal cyanides See other MERCURY COMPOUNDS 1799.l,4-Diiodo-l,3-butadiyne... [Pg.589]

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