Carbon dioxide oxysulfide

Heating cyclic mono-, di- or tri-thiocarbonates, usually in the presence of base, gives thiiranes and carbon dioxide, carbon oxysulfide or carbon disulfide respectively. The methiodide salts of 2-methylimino-l,3-oxathiolanes are converted to thiiranes with high stereoselectivity, except for 5-aryl-substituted oxathiolanes (Scheme 146) (80LA1779). Flash vacuum thermolysis of l,3-oxathiolan-5-ones causes loss of carbon dioxide and nearly quantitative formation of thiiranes of inverted configuration (Scheme 147) (80JA744). For example, thermolysis of c/s-2,4-diphenyl-1,3-oxathiolan-5-one gives trans-2,4-diphenyl-thiirane. 

In analogy to the reaction of decamethylsilicocene 41 with carbon dioxide leading to the generation of intermediary silanone 44, silicocene 41 was allowed to react with carbon oxysulfide under very mild conditions (—78 °C/toluene) to give the corresponding 1,3,2,4-dithiadisiletane derivative 81, a formal head-to-tail [2 + 2] cycloaddition reaction product of the initially formed silanethione 80 (Scheme 29)41b. 

R. A. J. Keijser, M. Jansen, V. G. Cooper, and H. F. P. Knaap. Depolarized Rayleigh scattering in carbon dioxide, carbon oxysulfide and carbon disulfide. Physica, S/ S93-600 (1971). 

Decamethylsilicocene (1) reacts with carbon dioxide already under mild conditions. Surprisingly, the products obtained depend on the solvent used. Bubbling CO2 at room temperature for about 3 through a solution of 1 in pyridine led to the eight-membered cyclic compound 1 in about 65 % yield, whereas in toluene as solvent the spiro heterocyclic compound II was formed in about 70 % yield. 1 reacts with carbon oxysulfide already under very mild conditions A toluene solution of 1 was added to liquid COS at -78°C. The dithiadisiletane III was isolated in about 50 % yield after a reaction time of 2 at this temperature. Compound III, already known in the literature as the reaction product of 1 with sulfur [6], is poorly soluble in organic solvents. 

Heteroallenes (e.g. caibon disulfide, carbon dioxide, carbon oxysulfide, isocyanates, isothiocyanates, ketenes, ketenimines) and vinylidenephosphoranes can form polar intermediates from which two isomeric products may result in a 1,4-cycloaddition (equation 113). The direction of the ring closure depends decisively upon the nucleophilic character of Z compared with that of Y. 

When the carbon dioxide is replaced by carbon disulfide, the reaction takes the p path because the much greater nucleophilicity of the sulfur atom makes the reaction 29 a - 29 b exothermic and, therefore, its transition step should resemble 29 a rather than 29 b. Consequently, the steric barrier impeding the P path to the hydantoin is missing on the P path to the 2,4-dithio-hydantoin, whereas the various steric factors impeding the a path are still present. The observation that, when carbon dioxide is replaced by carbon oxysulfide, the P- rather than the a-4-thiohydantoin is obtained, can be explained by similar reasoning. 

The results of the preparation of polyureas under mild conditions (a pressure of less than 40 atm of carbon dioxide and a temperature around 40 °C) and of poly thioureas (using diphenyl phosphite in pyridine) are compiled in Table 1728). Although the preparation of polyureas from carbon dioxide under drastic conditions (high temperatures and high pressures) or from carbon oxysulfide has been reported, neither preparative method is operative under moderate conditions, nor have the methods for the synthesis of polythioureas from carbon disulfide been described. 

Carbon disulfide—sulfiu dioxide complex Carbon monoselenide Carbon monosulfide Carbon monoxide Carbon monoxide dimer-water complex Carbon oxyselenide Carbon oxysulfide Carbon oxysulfide—carbon dioxide dimer complex Carbon oxysulfide—water complex... 

It is well known that carbon oxysulfide (COS) easily hydrolyzes to carbon dioxide and hydrogen sulfide in the presence of dilute sodium hydroxide. 

C bands 157-158, 170, 175-176, 179 calibration 28, 34, 304 of sealed cells 328 calibration standards 308 carbon dioxide 7,100-101,110,122,138-141, 145-149, 151, 154 carbon disulfide 326 carbon oxysulfide 146 carbon tetrachloride 326 carbonyl compounds 268-276 catechol 298 cells... 

Hydrogen sulfide cracks to form hydrogen, which produces carbon monoxide by the reverse water gas shift reaction widi the carbon dioxide. Carbon oxysulfide is formed by reaction of the carbon monoxide with sitlphm ... 

Carbon oxysulfide and caibon disulfide also form by reaction of hydrogen sulfide with carbon dioxide ... 

Related Reagents. Acetyl Cyanide Carbon Dioxide Carbon Oxysulfide fV,fV -Carbonyldiimidazole Diethyl Carbonate Methyl Chloroformate Methyl Magnesium Carbonate. 

Related Reactions. p-Keto ester formation from ketones may be achieved directly with dialkyl carbonates and dialkyl dicarbonates, or indirectly with dialkyl oxalates, methyl magnesium carbonate, and ethyl diethoxyphosphinyl formate. Re-giocontrol is problematical, however, and is more reliably effected by trapping enolates with carbon dioxide, carbon disulfide, or carbon oxysulfide followed by methylation. In the latter cases, the dithio and thiol esters are converted into the parent carboxy... 

Research and Bench-Scale Feasibility Studies. The reaction between carbon and sulfur dioxide at elevated temperatures is well known and has been used for numerous processes. For example, sulfur was produced at Trail, British Columbia from 1935 to 1943 by blowing sulfur dioxide and oxygen into the bottom of a coke-fired reduction furnace. Coke was charged at the top and ash was removed on a rotary grate at the bottom of the furnace. The hot zone of the furnace was kept at 1300°C to maintain rapid reaction rates and smooth operation. Sufficient sulfur dioxide was added to the gas to react with the carbon monoxide and carbon oxysulfide contained in the reduction furnace off-gas. Coal was con-... 

Nearly all the sulfur dioxide entering the process was converted selectively to hydrogen sulfide between 660 and 760 °C. The process was also applied to convert sulfur dioxide to sulfur at lower reaction temperatures. As shown in Figure 6, when 100% of the sulfur dioxide is converted, 90% reacts to form elemental sulfur while 10% yields different by-products such as hydrogen sulfide, carbon oxysulfide, carbon disulfide, etc. Nearly 100% selectivity to sulfur can be obtained at lower conversions corresponding to lower reaction temperatures. Lower temperatures caused lower conversions since the maximum contact time,... 

It has not yet been definitely ascertained whether the formation of carbon oxysulfide requires the previous liberation of sulfur from organic compounds or whether there is a direct removal of sulfur by carbon monoxide at higher temperatures from organic compounds or their pyrolysis fission products. It is possible that in some cases sulfur dioxide formed by ignition reacts in the gaseous state ... 

Lemmon, E. W, and Span, R., /. Chem. Eng. Data 51 785, 2006. [hydrogen sulfide, krypton, nitrous oxide, sulfur dioxide, xenon, carbon monoxide, carbon oxysulfide, R41-fluoromethane, neopentane]... 

Baglio, J. A. Lanthanum oxysulfide as a catalyst for the oxidation of carbon monoxide and carbonyl sulfide by sulfur dioxide. Ind. Eng. Chem. Prod. Res. Develop. 1982, 21(1), 38-41. 

Lau, N. T. Fang, M. On the Formation of Carbonyl Sulfide in the Reduction of Sulfur Dioxide by Carbon Monoxide on Lanthanum Oxysulfide Catalyst A study by XPS andTPR/MS. J. Catal 1998, 179,343-349. 

The formation of carbon oxysitlfide and carbon disitlfide in the furnace leads to problems when high overall conversion is reqitired. Alitmina catalysts are not sufficiently active to convert carbon disitlfide and oxysulfide in the first reactor unless a high temperature is reached at the bottom of the bed. When this is not possible, the bottom third of the bed can be loaded with either an iron-promoted alumina or a newer titania catalyst. Cobalt/molybdate/alumina catalysts were also tested in early attempts to hydrogenate the impurities, but it was found that conditions in the first reactor favored sulfur dioxide hydrogenation instead. All of the catalyst types used in Claus sulfur recovery plants are described in Tables 2.10 and 2.11. 

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