High-temperature oxidation and sulfidation

Stringer, J. (1990), in High-Temperature Oxidation and Sulfidation Processes, Embury, J. D. (Ed.). New York Pergamon Press, pp. 257-275. 

Indium also combines with nonmetaUic elements and with metalloids such as N, P, Sb, As, Te, and Se. Many of the latter compounds ate semiconducting as ate the oxide and sulfide. Indium antimonide [1312-41 -0], InSb indium arsenide [1303-11-3], In As and indium phosphide [22398-80-7], InP, ate the principal semiconducting compounds. These ate all prepared by direct combination of the highly purified elements at elevated temperature under controlled conditions. 

Nickel was first isolated in 1751, and a relatively pure metal was prepared in 1804. In nature, nickel is found primarily as oxide and sulfide ores (USPHS 1977). It has high electrical and thermal conductivities and is resistant to corrosion at environmental temperatures between -20°C and +30°C (Chau and Kulikovsky-Cordeiro 1995). Nickel, also known as carbonyl nickel powder or C.I. No. 77775, has a CAS number of 7440-02-0. Metallic nickel is a hard, lustrous, silvery white metal with a specific gravity of 8.9, a melting point of about 1455°C, and a boiling point at about 2732°C. It is insoluble in water and ammonium hydroxide, soluble in dilute nitric acid or aqua regia, and slightly soluble in hydrochloric and sulfuric acid. Nickel has an atomic weight of 58.71. Nickel is... 

At the initial reaction stage, the activity of oxide Mo-Ni catalysts is higher than that of Mo catalysts by a factor of 5. In three hours, this value decreases to 4 (Fig. la). For the sulfide samples, this effect is less pronounced (Fig. lb). In the next run, the catalyst activity was determined at 400 C, then the temperature was decreased to 300 C. This procedure was repeated for several times. For both oxide and sulfide molybdenum catalysts, activity and the product composition are reproduced with high accuracy in a number of experiments (Fig. 2). At high temperature, the bimetallic catalysts are quickly deactivated during the reaction (and the experimental cycles are not reproducible). 

The fact that butane is not found in the reaction products indicates that THF is not dehydrated (scheme 3) on the study catalysts and oxygen is removed from THF by hydrogenolysis (schemes 1 and 2). On the oxide and sulfide molybdenum catalysts, butane is the main reaction product, that is why hydrogenolysis predominantly follows scheme 1. This is also true for bimetallic sulfide catalysts, if the reaction occurs at high temperature. For the rest catalysts, a part of butenes in the reaction products is rather high. This suggests that hydrogenolysis of the most part of THF follows scheme 2. 

Sources of transition metals Copper, silver, gold, platinum, and palladium are the only transition metals that are unreactive enough to be found in nature uncombined with other elements. All other transition metals are found in nature combined with nonmetals in minerals such as oxides and sulfides. Recall that minerals are mixed with other materials in ores. Metallurgy is the branch of applied science that studies and designs methods for extracting metals and their compounds from ores. The methods are divided into those that rely on high temperatures to extract the metal, those that use solutions, and those that rely on electricity. Electricity also is used to purify a metal extracted by high temperatures or solutions. 

In the fifteen years since publication of the first edition of Comprehensive Coordination Chemistry (CCC, 1987), group 5 chemistry has been part of the intensive development of ceramic, optical, and magnetic materials based upon metal borides, nitrides, phosphides, oxides, and sulfides. A major impetus came from the discovery of the high-temperature superconducting oxides. In addition, the search for new routes to these materials via sol-gel or chemical vapor deposition techniques has spurred growth in metal amido, oxo, alkoxo, thio, and carboxylato chemistry. 

There are many organosulfur compounds, which have been used in formulating lubricant additives. The sulfide, disulfide, and polysulfide linkages, incorporated into novel compositions-of-matter, serve various functions, such as corrosion inhibition, oxidation resistance, high-temperature stability, and static prevention. ... 

Bismuth sulfide (Bi2S3) is a dark brown to grayish black solid, readily obtained by heating bismuth with sulfur or by adding an alkali sulfide to the aqueous solution of bismuth(III) salts. It is used as a high temperature lubricant. The sulfide is almost insoluble in water, but dissolves in concentrated nitric acid and hot hydrochloric acid. Concentrated aqueous potassium sulfide dissolves bismuth sulfide to form bismuth thiobismuthate KBi 2, which is readily oxidized in air. Fusion of the sulfide with bismuth halide (BiXa) gives the corresponding halosulfide (BiXS) as an air-stable solid. Bismuth sulfide of 99% purity costs US 153.30 ( 37 9(X)) per 250 g. 

Cuprous Binary Compounds. The oxide and sulfide are more stable than the corresponding Cu11 compounds at high temperatures. Cu20 is made as a yellow powder by controlled reduction of an alkaline solution of a cupric salt with hydrazine or, as red crystals, by thermal decomposition of CuO. A yellow hydroxide is precipitated from the metastable Cu+ solution mentioned above. Cu2S is a black crystalline solidprepared by heating copper and sulfur in absence of air. 

Oxides and sulfides such as Cr203 and MoS2 also catalyse dehydrogenation, although only at rather high temperatures 123 they also catalyse cyclization of saturated and unsaturated aliphatic to aromatic compounds.124 Chemical methods of dehydrogenation are applicable in a large number of... 

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