Sulfides reactions atmosphere

Air sparging or reaction of dissolved hydrogen sulfide with atmospheric oxygen could yield elemental sulfur. 

Hydrogen sulfide in the reaction atmosphere has been reported to accelerate liquefaction directly, in addition to controlling the extent of sulfiding of iron, Ni-Mo, and Co-Mo catalysts (39, 40). 

Direct Kinetic and Mechanistic Study of the OH-Dimethyl Sulfide Reaction Under Atmospheric Conditions... 

The ternary phases AMX2 (A = Li, Na, or K M = Cr, Ti, or V X = S or Se) have been synthesized by the reaction of mixtures of the alkali metal carbonate and the transition metal oxide in a hydrogen sulfide gas atmosphere at elevated temperature [73]. The reactions are carried out in graphite crucibles and it is usually found to be advantageous to use an excess of the metal carbonate. Structural characterization by X-ray and neutron diffraction confirmed their layered structure. These ternary phases may serve as a synthetic intermediate to new metastable layered metal dichalcogenides by oxidative removal (i.e., deintercalation) of the alkali metal. For example, this method has been used to prepare VS2 and CrSe2, which are difficult to synthesize by conventional high-temperature combination of the elements [74,75]. 

Ma.nufa.cture. Nickel carbonyl can be prepared by the direct combination of carbon monoxide and metallic nickel (77). The presence of sulfur, the surface area, and the surface activity of the nickel affect the formation of nickel carbonyl (78). The thermodynamics of formation and reaction are documented (79). Two commercial processes are used for large-scale production (80). An atmospheric method, whereby carbon monoxide is passed over nickel sulfide and freshly reduced nickel metal, is used in the United Kingdom to produce pure nickel carbonyl (81). The second method, used in Canada, involves high pressure CO in the formation of iron and nickel carbonyls the two are separated by distillation (81). Very high pressure CO is required for the formation of cobalt carbonyl and a method has been described where the mixed carbonyls are scmbbed with ammonia or an amine and the cobalt is extracted as the ammine carbonyl (82). A discontinued commercial process in the United States involved the reaction of carbon monoxide with nickel sulfate solution. 

Sulfurization of unsaturated compounds and meicaptans is normally carried out at atmospheric pressure, in a mild or stainless steel, batch-reaction vessel equipped with an overhead condenser, nitrogen atmosphere, an agitator, heating media capable of 120—215°C temperatures and a scmbber (typically caustic bleach or diethanolamine) capable of handling hydrogen sulfide. If the reaction iavolves the use of H2S as a reactant or the olefin or mercaptan is a low boiling material, a stainless steel pressurized vessel is recommended. 

Atmosphere—Water Interaction. Although water is a very minor component of the atmosphere, less than 10 vol % of the atmosphere consisting of water, many important reactions occur ki the water droplets of cloud, fog, and rain. The atmosphere is an oxic environment ki its water phase, gigantic quantities of reductants, such as organic substances, Fe(II), SO2, CH SCH (dimethyl sulfide), and nitrogen oxides, are oxidized by oxidants such as oxygen, OH radicals, H2O2, and Fe(III). 

The synthetic pigment is produced by one of several related procedures. The best quahty product is made by reaction of an aqueous solution of CdSO or CdCl with a solution of an alkaline metal sulfide or H2S. Zn, Se, or Hg may be added to the CdS to produce shade vatiations. After precipitation, the color is filtered, washed, and calcined in an inert atmosphere at 500—600°C. 

Chemical Reactivity - Reactivity with Water. Reacts with liquid water or atmospheric moisture to liberate toxic hydrogen sulfide gas Reactivity with Common Materials No reaction Stability During Transport Can be ignited by friction Neutralizing Agents for Acids and Caustics Not pertinent Polymerization Not pertinent Inhibitor of Polymerization Not pertinent. 

The hydrogenation of benzene produces cyclohexane. Many catalyst systems, such as Ni/alumina and Ni/Pd, are used for the reaction. General reaction conditions are 160-220°C and 25-30 atmospheres. Higher temperatures and pressures may also be used with sulfided catalysts ... 

Solid catalysts for the metathesis reaction are mainly transition metal oxides, carbonyls, or sulfides deposited on high surface area supports (oxides and phosphates). After activation, a wide variety of solid catalysts is effective, for the metathesis of alkenes. Table I (1, 34 38) gives a survey of the more efficient catalysts which have been reported to convert propene into ethene and linear butenes. The most active ones contain rhenium, molybdenum, or tungsten. An outstanding catalyst is rhenium oxide on alumina, which is active under very mild conditions, viz. room temperature and atmospheric pressure, yielding exclusively the primary metathesis products. 

Figure 4-13 shows an example from a three-dimensional model simulation of the global atmospheric sulfur balance (Feichter et al, 1996). The model had a grid resolution of about 500 km in the horizontal and on average 1 km in the vertical. The chemical scheme of the model included emissions of dimethyl sulfide (DMS) from the oceans and SO2 from industrial processes and volcanoes. Atmospheric DMS is oxidized by the hydroxyl radical to form SO2, which, in turn, is further oxidized to sulfuric acid and sulfates by reaction with either hydroxyl radical in the gas phase or with hydrogen peroxide or ozone in cloud droplets. Both SO2 and aerosol sulfate are removed from the atmosphere by dry and wet deposition processes. The reasonable agreement between the simulated and observed wet deposition of sulfate indicates that the most important processes affecting the atmospheric sulfur balance have been adequately treated in the model. 

The vast majority of sulfur at any given time is in the lithosphere. The atmosphere, hydrosphere, and biosphere, on the other hand, are where most transfer of sulfur takes place. The role of the biosphere often involves reactions that result in the movement of sulfur from one reservoir to another. The burning of coal by humans (which oxidizes fossilized sulfur to SO2 gas) and the reduction of seawater sulfate by phytoplankton which can lead to the creation of another gas, dimethyl sulfide (CH3SCH3), are examples of such processes. 

Another one is the primary atmospheric sink reaction for carbonyl sulfide ... 

The effect of complex formation on the solubility of a solid can be observed in the home. Silver dinnerware eventually becomes discolored by an unsightly black tarnish of Ag2 S, formed from the reaction of the silver surface with small amounts of H2 S present in the atmosphere. Silver sulfide is highly insoluble in water. Commercial silver polishes contain ligands that form strong soluble complexes with Ag ions. If a tarnished serving pan is rubbed with a polish, the black tarnish dissolves, returning the silver to its brilliant shine. 

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