Monoxide and Sulfur

Chemica.1 Properties. Reviews of carbonyl sulfide chemistry are available (18,23,24). Carbonyl sulfide is a stable compound and can be stored under pressure ia steel cylinders as compressed gas ia equiUbrium with Hquid. At ca 600°C carbonyl sulfide disproportionates to carbon dioxide and carbon disulfide at ca 900°C it dissociates to carbon monoxide and sulfur. It bums with a blue flame to carbon dioxide and sulfur dioxide. Carbonyl sulfide reacts... 

Phosphoric acid-based systems, for cellulosics, 11 488 Phosphoric acid esters, 24 159 Phosphoric acid fuel cells (PAFC), 13 858— 860 12 203-204, 216-219 19 626 effects of carbon monoxide and sulfur in, 12 219... 

COS flames exhibit two zones. In the first zone, carbon monoxide and sulfur dioxide form and in the second zone, the carbon monoxide is converted into carbon dioxide. Since these flames are hydrogen-free, it is not surprising that the CO conversion in the second zone is rapidly accelerated by adding a very small amount of water to the system. 

This positive value for the free energy of reaction means that the reaction will not proceed to the right. Instead, the reverse reaction is favored, with CO and SO3 reacting to yield CO2 and SO,. Moving to the left minimizes the free energy. Of course, this reaction can take place only if both carbon monoxide and sulfur trioxide are present initially. If you start with only carbon dioxide and sulfur dioxide, no reaction can occur. 

When the carbon dioxide is replaced with carbonyl sulfide, generated in situ from carbon monoxide and sulfur, 4-thioxo-2-quinazolinones 818 are produced <2000HAC428>. 

Chemicals can be labeled as either a primary air pollutant or secondary air pollutant. Primary air pollutants are those such as carbon monoxide and sulfur dioxide that enter the atmosphere directly as a result of human or natural events. Carbon monoxide s primary source in the atmosphere is the incomplete combustion of gasoline. Hundreds of different chemicals are present in gasoline. The combustion of octane, C Hj, can be used to represent the general reaction of hydrocarbons in an automobile engine to produce energy ... 

Thermal extrusion of a sulfur atom is the most common thermal reaction of a thiepin. The mechanism of this thermal process involves two orbital symmetry controlled reactions (69CC1167). The initial concerted step involving a reversible disrotatory electrocyclic rearrangement is followed by a concerted cheleotropic elimination of sulfur (Scheme 29). Similar aromatization reactions occur with thiepin 1-oxides and thiepin 1,1-dioxides, accompanied by the extrusion of sulfur monoxide and sulfur dioxide respectively. Since only a summary of the major factors influencing the thermal stability of thiepins was given in Section... 

A study of the gas phase reactions of sulfur atoms with ethylene and propylene lias been recently carried out by Strausz and Gunning (98). Atomic sulfur, presumably in the (lD) metastable state, was generated by photolysis of carbonyl sulfide in the wavelength region 2550-2290 A., and the study was restricted to 25°C. Pure carbonyl sulfide yields carbon monoxide and sulfur as the main products. When ethylene and propylene are added, the carbon monoxide yield is decreased, tending to a value one half as large as in the absence of the olefins. Cyclic sulfides are simultaneously formed by addition of S atoms to the two olefins. The mechanism which accounts for the main features of the process is... 

Some aspects of the reactivity of the A-frames formed by Reaction 1 have been explored. Carbon monoxide and sulfur dioxide are readily lost from the respective adducts upon mild heating or exposure to vacuum. The insertions of isocyanides or sulfur have not been reversed. However the oxidation of Pd2(dpm)2(/Lt-S)Cl2 to Pd2(dpm)2-(/x-S02)Cl2 can be effected by using m-chloroperbenzoic acid as oxidant. Acetylene addition is photoreversible photolysis of Pd2(dpm)2-(/Lt-C2 C02CH3 2)C12 forms dimethylacetylene dicarboxylate and Pd2(dpm)2Cl2 (14). Pd2(dpm)2X2 is a catalyst for converting dimethyl-acetylene dicarboxylate into hexamethyl mellitate, and Pd2(dpm)2-(/it-C2 C02CH3 2)X2, which forms during the reaction, is presumed to be an intermediate. 

Concentrated sulfuric acid Evolution of carbon monoxide and sulfur dioxide (poisonous)... 

Prompted in part by the results obtained in the previous section, the effects of adsorbed carbon monoxide and sulfur on the voltammetric behavior of single crystal Ni surfaces were examined in more detail. 

The dimeric Pd(I) complex Pd2(dpm)2X2 involves two planar metal centers linked by a metal-metal bond. The Pd-Pd separation in these molecules is about 2.7 A. (16,17) These dimers readily undergo insertion of small molecules to give molecular A-frames via reaction (10). (14,18-22) Carbon monoxide and sulfur dioxide... 

In further purification, carbon dioxide, residual carbon monoxide, and sulfur compounds (only present in the synthesis gas from partial oxidation) have to be removed as they are not only a useless ballast but above all poisons for the ammonia synthesis catalyst. 

Hong Y. and Fegley B. (1997) Formation of carbonyl sulfide (OCS) from carbon monoxide and sulfur vapor and applications to Venus. Icarus 130(2), 495-504. 

The stable dithiirane 5-oxide (4) is converted to sulfine (15) and triphenylphosphine sulfide upon treatment with triphenylphosphine (93JA4914). When heated, (4) decomposes to give thioketone (16), sulfine (15), and dicarbonyl compound (17). Compounds (16) and (15) result from loss of sulfur monoxide and sulfur, respectively, from (4). Thioketone (16) exists in equilibrium with oxathietane (18). The rate of thermal decomposition of (4) was found to be dependent on its concentration, with higher rates at higher concentrations. The authors suggest that this observation is indicative of a decomposition pathway involving the sulfur and sulfur monoxide products. Thermolysis of (4) also leads to isomerization of (12) in addition to the products described above. 

Supported ruthenium carbido-cluster catalysts for the catalytic removal of nitrogen monoxide and sulfur dioxide the preparation process monitored by sulfur K-edge X-ray absorption near-edge structure... 

Fumigants containing potassium nitrate, sulfur, charcoal powder and sawdust should be mentioned. These exterminate field rodents in their burrows by the evolution of carbon monoxide and sulfur dioxide. In a similar way, carbon disulfide kills by this vapour phase effect. 

In some cases the insertion reactions are reversible. This is the case with the palladium complexes for carbon monoxide and sulfur dioxide. With acetylenes, preliminary studies indicate that the insertion products can be made to eliminate the acetylene on photolysis. The remaining A-frames shown in Figure 5.16 are formed irreversibly. 

Some examples of the reaction involving the addition of carbon monoxide and sulfur dioxide to rhodium(I) and iridium(I) A-frames are shown in equation... 

Reactant ligands for this series of reactions appear to be limited so far to carbon monoxide and sulfur dioxide. It would be interesting to learn what othfer potential ligands (isocyanides, acetylenes, etc.) can also be added to the A-frame and face-to-face reactants in this fashion. 

Although the occupational human health impact of bioelectricity is smaller than that of coal-fired electricity, the overall human health impact of bioelectricity is higher than that of electricity because of the large contribution of environmental human health impact (Table 14.7). In both systems, the environmental human health impacts come from the emission of carbon monoxide, methane, and sulfur oxides. The hotspots are also similar for the two product systems, because most of these emissions come from the electricity and bioelectricity generation stages. However, the contributions of these emissions are a htde bit different, as sulfur dioxide from coal contributes mostly to human health impacts of electricity, while in the bioelectricity product system there is a small difference in contribution of carbon monoxide and sulfur oxides to human health impact. Fig. 14.5 represents the contributions of main emissions to environmental human health impact for the two product systems. 

Asanuma, H., et al.. Adsorption of nitrogen monoxide by the chelate resin-immobilized iron(ll) complex and its application for simultaneous removal of nitrogen monoxide and sulfur dioxide. Ind. Eng. Chem. Res., 29( 11). 2267-2272(1990). 

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