Hydrogen sulfide, viii

Gruzdkov, Yu.A., Savinov, E.N., and Parmon, V.N., Photocatalytic decomposition of hydrogen sulfide in the presence of polymer immobilized cadmium sulfide. Promotion by I and VIII group metals, Int.. Hydrogen Energ., 12, 393, 1987. 

Clarke, E.C.W. and D.N. Glew (1971), Aqueous nonelectrolyte solutions, Part VIII. Deuterium and hydrogen sulfides solubilities in deuterium oxide and water, Can. J. Chem., 49, 691-698. Corsi, R.L., S. Birkett, H. Melcer, and J. Bell (1995), Control of VOC emissions from sewers A multi-parameter assessment, Water Sci. Tech, 31(7), 147-157. 

Part VIII. Deuterium and Hydrogen Sulfides Solubilities in Deuterium Oxide and Water," Can. J. Chem., 1971, 49, 691-98. 

Group VIII sulfides are obtained by the low-temperature precipitation described above. However, a preferred synthesis involves the direct sulfidation with hydrogen sulfide of ammonium hexachlorometallates. A good example is found in the synthesis of RuS2 and Rh2S3 (28). However, synthetic techniques and the solid-state chemistry of the Group VIII sulfides are not as well developed as those for the Group VII sulfides, and much research needs... 

Since the evolution of hydrogen sulfide could have a major bearing on the final acceptance of the S-A-S material in pavement construction, a study of the extent of hydrogen sulfide gas evolution encountered over a range of process variables was undertaken. A number of concentration levels and their associated environmental effects are shown in Table VIII. 

Samplings were taken during the mixing and compaction phases of sample preparation. The results of these tests are given in Table IX and show that the concentrations of hydrogen sulfide evolved ranged from 0.1 to 2.75 ppm. These concentrations are well within the safe level for exposure to hydrogen sulfide as set forth in Table VIII. 

The ease with which thiophenes are formed in the reaction of acetylenic epoxides " " and of polyacetylenes with hydrogen sulfide is of great interest in connection with the biosynthesis of the naturally occurring thiophenes (cf. Section VIII,A) and also of preparative importance. 2-Methyl-l,2-oxido-5-hexene-3-yne (56) in water containing barium hydroxide reacts with H2S at 50°C to give 4-... 

These reactions take place normally in a trickle bed downflow reactor at high hydrogen pressures (1500 to 4000 psi) and temperatures in excess of 600°F. The catalyst is frequently referred to as dual function since it promotes both cracking and hydrogenation. The catalyst base material is usually silica-alumina with metal oxides from groups VI and VIII (nickel, cobalt, molybdenum, tungsten). The active forms are the metal sulfides. Fractionation provides the waxy lubes cuts which are subsequently dewaxed and hydrofinished. 

VIII. Reactions Catalyzed by Nickel Sulfide 1. Destructive Hydrogenation... 

Catalysts suitable for selective hydrogenation of acetylenic compounds in cracked gas streams contain elements of group VI and VIII of the periodic table. An early catalyst was molybdenum sulfide supported on activated alumina (Key and Eastwood, 1946). This was followed by the development of cobalt molybdate and nickel based catalysts (Giaro, 1956 Barry, 1950). Modem catalysts for impure (sulfur-bearing) cracked gas streams typically contain nickel, cobalt, and chromium on a silica-alumina base (United Catalysts, 1993). 

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