Sulfur reactions with hydrogen

Step 2 On reaction with hydrogen chloride m an anhydrous solvent the thiocarbonyl sulfur of the PTC derivative attacks the carbonyl carbon of the N terminal ammo acid The N terminal ammo acid is cleaved as a thiazolone derivative from the remainder of the peptide... 

Toxic or malodorous pollutants can be removed from industrial gas streams by reaction with hydrogen peroxide (174,175). Many Hquid-phase methods have been patented for the removal of NO gases (138,142,174,176—178), sulfur dioxide, reduced sulfur compounds, amines (154,171,172), and phenols (169). Other effluent treatments include the reduction of biological oxygen demand (BOD) and COD, color, odor (142,179,180), and chlorine concentration. 

In the acid-leaching process, the oxide ore is leached with sulfuric acid at elevated temperature and pressure, which causes nickel, but not iron, to enter into solution. The leach solution is purified, foHowed by reaction with hydrogen sulfide and subsequent precipitation of nickel and cobalt sulfides. 

Sulfur combines directly with hydrogen at 150—200°C to form hydrogen sulfide. Molten sulfur reacts with hydrogen to form hydrogen polysulfides. At red heat, sulfur and carbon unite to form carbon disulfide. This is a commercially important reaction in Europe, although natural gas is used to produce carbon disulfide in the United States. In aqueous solutions of alkaU carbonates and alkaU and alkaline-earth hydroxides, sulfur reacts to form sulfides, polysulfides, thiosulfates, and sulfites. 

The Claus process, which involves the reaction of sulfur dioxide with hydrogen sulfide to produce sulfur in a furnace, is important in the production of sulfur from sour natural gas or by-product sulfur-containing gases (see Sulfurremoval and recovery). 

Catalysis. Catalytic properties of the activated carbon surface are useful in both inorganic and organic synthesis. For example, the fumigant sulfuryl fluoride is made by reaction of sulfur dioxide with hydrogen fluoride and fluorine over activated carbon (114). Activated carbon also catalyzes the addition of halogens across a carbon—carbon double bond in the production of a variety of organic haUdes (85) and is used in the production of phosgene... 

Aj Hydrodesulfurization Removal of sulfur compounds from crude oil by reaction with hydrogen on CO - Mo on alumina. 

Barium hydroxide decomposes to barium oxide when heated to 800°C. Reaction with carbon dioxide gives barium carbonate. Its aqueous solution, being highly alkahne, undergoes neutrahzation reactions with acids. Thus, it forms barium sulfate and barium phosphate with sulfuric and phosphoric acids, respectively. Reaction with hydrogen sulfide produces barium sulfide. Precipitation of many insoluble, or less soluble barium salts, may result from double decomposition reaction when Ba(OH)2 aqueous solution is mixed with many solutions of other metal salts. 

Iron(lll) sulfate may be prepared by oxidation of iron(ll) sulfate by hydrogen peroxide, nitric acid or any other suitable oxidizing agent. The reaction is carried out in sulfuric acid. Balanced molecular equations for the reactions with hydrogen peroxide and nitric acid are as follows ... 

Sulfur reacts with hydrogen at 260 to 350°C forming hydrogen sulfide. The reaction is slow at this temperature and does not go to completion. The reaction is catalyzed by activated alumina. 

Sulfur bridging of 2,2 -, 3,3 -, and 4,4 -bipyridines by reaction with hydrogen sulfide over alumina at 630 C affords a synthesis of thieno-dipyridines. For example, 2,2 -bipyridine gives compound 112. Somewhat similarly, dibromo-Af-methylmaleimide with 4,4 -bipyridine forms... 

A modihcation on verapamil uses a spiro-dithiane moiety to supply the quaternary center. Reaction of veratraldehyde (64-1) with propane 1,3-dithiol leads to dithiane (64-2). Reaction with hydrogen peroxide oxidizes the ring sulfur atoms to... 

There are no real thermodynamic limits in the removal of sulfur from any organic sulfur compound by reaction with hydrogen (1, 2, 5). There are, however, limits on the overall rates of conversion that may be achieved by increasing the temperature of the reaction. A classic limitation in rates is the result of the inverse relationship between adsorption on a catalytic surface and temperature. This may be a problem with dialkyldibenzothio-phenes, which have steric limitations for adsorption. 

In addition, several metal-coordinated thials have been described in studies pertaining to hydrodesulfurization (HDS) reactions. This catalytic process is used to remove sulfur from organosulfur compounds present in fossil fuel feedstocks by reaction with hydrogen and a transition metal (Rh, Ir) and possesses both commercial and environmental importance393,394. 

---