Hydrogen sulfide obtaining sulfur from

The reaction at Eq. (12) allows the preparation of Na2S4 and K2S5 from the alkali metals, hydrogen sulfide and sulfur in anhydrous ethanol (ROH). First the metal is dissolved in the alcohol with formation of ethanolate (MOR) and hydrogen. Bubbling of H2S into this solution produces the hydrogen sulfide (MHS). To obtain the polysulfide the solution is refluxed with the calculated amount of elemental sulfur. After partial evaporation of the solvent and subsequent cooling the product precipitates. 

The alkali-soluble protein of the peel of lemons treated with hydrogen sulfide, sulfur dioxide, and sulfuric acid contained radioactive sulfur, but the fruit treated with hydrogen sulfide had a significantly lower per cent specific activity in the alkali-soluble protein fraction than did the sulfur dioxide or sulfuric acid treated fruits (Table VII). These results suggest that sulfur dioxide and sulfuric acid react with protein more directly, while hydrogen sulfide perhaps must be oxidized first, as indicated in Table III. It also appears (from Table VII) that the alkali-soluble protein may have been dismuted as the amounts isolated were less in both the hydrogen sulfide and sulfur dioxide treated fruit than in the incubated or nonincubated controls. Other evidence of dismutation has been obtained in experiments where incubation at 60° C. was accompanied by the production of free ammonia (18), and the recovery of free ammonia and six amino acids in the exudates of incubated and sulfur-dusted fruits (18). 

The most important applications of hydrogen sulfide involve the production of sodium sulfide and other inorganic sulfides. Hydrogen sulfide obtained as a by-product often is converted into sulfuric acid. It also is used in organic synthesis to make thiols or mercaptans. Other applications are in metallurgy for extracting nickel, copper, and cobalt as sulfides from their minerals and in classical qualitative analytical methods for precipitation of many metals (see Reactions). It also is used in producing heavy water for nuclear reactors. 

Emissions. An environmental assessment has been carried out to evaluate the effects of sulfur-asphalt during and after construction. Ambient air samples were taken from points around the pugmill and paver and analyzed for hydrogen sulfide (H2S), sulfur dioxide (S02), carbon disulfide (CS2), carbonyl sulfide (COS), mercaptans (RSH), and total hydrocarbons. The results indicated that no problems exist in terms of current health standards during construction or after. Typical test results obtained at the pugmill and methods used are given in Table II. 

The chemiluminescence spectrum obtained from the reaction of ozone with methyl mercaptan at a pressure of 0.2 torr is shown in Figure 5. Reaction of hydrogen sulfide with dimethylsulfide with ozone give identical spectra consisting of a broad structureless band centered at approximately 370 nm (uncorrected for spectral sensitivity of the detection system). We have recently shown that this emission is identical to the fluorescence spectrum of sulfur dioxide (16). Since ozone oxidizes hydrogen sulfide to sulfur dioxide and water in the gas phase 17, 18), this result is not surprising. 

Four samples of sulfur from four different condensers were obtained from the Petrogas plant in Balzac, Alberta. At the plant the hydrogen sulfide level varied from 168 to 18.5 ppm. Table I indicates that substantially lower values were obtained in the laboratory before the samples had been remelted. A further reduction occurred as a result of remelting and storage. 

Thiols can be obtained from carbonyl compounds, the oxygen atom of the latter being replaced by SH and H, if hydrogen sulfide or sulfur is used in the presence of hydrogen and a catalyst that is not poisoned by sulfur 391... 

Studies by Mayer and his school have shown that replacement of the nitrogen group of enamines provides a synthetic method capable of considerable variation and especially useful for the preparation of sulfur heterocycles.486 For example, 3i/-l,2-dithiol-3-thiones are obtained by the action of hydrogen sulfide and sulfur on enamines, particularly in a polar solvent, at room temperature.487 If the sulfur is omitted, then at higher temperatures and in an apolar solvent 2JE7-thiopyrone-2-thiones are formed preferentially.488 Also, enamines can be cleaved to 1,1-dithiols by sulfur 489 enamines obtained from p-oxo carboxylic esters thus give 60-90% yields of / -thioxo carboxylic esters.490... 

Hydrogen sulfide, H2S, recovered from natural gas and petroleum is also a source of free sulfur. The sulfur is obtained from the hydrogen sulfide gas by the Claus process, a method of obtaining free sulfur by the partial burning of hydrogen sulfide. The partial burning of hydrogen sulfide produces some sulfur, as well as sulfur dioxide. 

Sulfur, another Group VIA element, occurs in sulfate and sulfide minerals. Free sulfur, Sg, occurring in deep underground deposits is mined by the Frasch process. Sulfur is also produced by the Claus process, in which hydrogen sulfide (obtained from natural gas and petroleum) is partially burned. Most of the sulfur is used to prepare sulfuric acid by the contact process. In this process, sulfur is burned to sulfur dioxide, SO2, which in the presence of a catalyst and oxygen forms sulfur trioxide, SO3. This oxide dissolves in concentrated sulfuric acid, which when diluted with water gives additional sulfuric acid. Sulfuric acid is the most important compound of sulfur. 

Other sulfur compounds such as thiourea, ammonium dithiocarbamate, or hydrogen sulfide also lead to 2-mercaptothiazoles. Thus thiourea has been used in the syntheses of 4,5-dimethyl (369) and 4-aryl-2-mercapto-thiazoles (Table 11-30) (519). The reactions were carried out by condensing the ia -thiocyanatoketones with thiourea in alcohol and water acidified with hydrochloric acid. By this procedure, 4-aryl-2-mercaptothiazoles were obtained in yields of 40 to 80% with bis-(4-aryl-2-thiazolyl) sulfides as by-products (519). These latter products (194) have also been observed as a result of the action of thiourea on 2-chloro-4-arylthiazole under the same experimental conditions. They can be separated from 2-mercaptothiazoles because of their different degrees of solubility in sodium hydroxide solution at 5%. In this medium bis-(4-phenyl-2-thiazolyl)sulfide is... 

Sulfur, another inorganic petrochemical, is obtained by the oxidation of hydrogen sulfide 2H2S + O2 — 2H2 0 + 2S. Hydrogen sulfide is a constituent of natural gas and also of the majority of refinery gas streams, especially those off-gases from hydrodesulfurization processes. A majority of the sulfur is converted to sulfuric acid for the manufacture of fertilizers and other chemicals. Other uses for sulfur include the production of carbon disulfide, refined sulfur, and pulp and paper industry chemicals. 

Reactions with Sulfur Compounds. Thiosuccinic anhydride [3194-60-3] is obtained by reaction of diethyl or diphenyl succinate [621-14-7] with potassium hydrogen sulfide followed by acidification (eq. 10). Thiosuccinic anhydride is also obtained from succinic anhydride and hydrogen sulfide under pressure (121). 

Hydrogen sulfide has been produced in commercial quantities by the direct combination of the elements. The reaction of hydrogen and sulfur vapor proceeds at ca 500°C in the presence of a catalyst, eg, bauxite, an aluminosihcate, or cobalt molybdate. This process yields hydrogen sulfide that is of good purity and is suitable for preparation of sodium sulfide and sodium hydrosulfide (see Sodium compounds). Most hydrogen sulfide used commercially is either a by-product or is obtained from sour natural gas. 

In a modem carbon disulfide plant, all operations are continuous and under automatic control. On-stream times in excess of 90% are obtainable. The process is in three steps melting and purification of sulfur production and purification of carbon disulfide and recovery of sulfur from by-product hydrogen sulfide. A typical process appears in the flow diagram of Figure 1 (50). 

Sulfur is a reactive, nonmetallic element naturally found in nature in a free or combined state. Large deposits of elemental sulfur are found in various parts of the world, with some of the largest being along the coastal plains of Louisiana. In its combined form, sulfur is naturally present in sulfide ores of metals such as iron, zinc, copper, and lead. It is also a constituent of natural gas and refinery gas streams in the form of hydrogen sulfide. Different processes have been developed for obtaining sulfur and sulfuric acid from these three sources. 

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