Hydrogen sulfide reaction with

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. 

Cyanamidopyrimidine (15) was converted to the thioureido derivative 16 by reaction with hydrogen sulfide and ammonium hydroxide and then cyclrzed to 18 with hydrazine hydrate. Cyclization to 18 presumably took place by elimination of a molecule of ammonia from the aminoguanidine intermediate 17 (65JCS3357) (Scheme 11). 

These profiles clearly show that in the gas phase the alkylations of both ammonia and water by o-QM are assisted by an additional water molecule H-bonded to o-QM (water-catalyzed mechanism), since S4 and S5 TSs are favored over their uncatalyzed counterparts (SI and S2) by 5.6 and4.0 kcal/mol [at the B3LYP/6-311 + G(d,p) level], respectively. In contrast, the reaction with hydrogen sulfide in the gas phase shows a slight preference for a direct alkylation without water assistance (by 0.8 kcal/mol). 

Examples have been described of cyclization of bis(azostilbene) derivatives by reaction with hydrogen sulfide and hydrochloric acid, by irradiation, and by heat. 2,4,5-Triphenyltriazole is formed in each case. Nonoxidative cyclization of bis arylhydrazones is also reported. A reaction related to these is the oxidation of benzaldehyde... 

Interestingly, compounds 201 can be easily detertbutylated to give the corresponding thiols 202 upon treatment with mercury(II) acetate in trifluoroacetic acid followed by reaction with hydrogen sulfide in 54-79% yield °. 

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. 

In a strongly acidic solution, its reaction with hydrogen sulfide yields an amorphous modification of germanium(IV) sulfide, GeS2. 

Reaction with hydrogen sulfide forms black precipitate of lead sulfide, PbS. A paper soaked with lead acetate solution turns black on exposure to H2S, a test often used to detect sulfide. 

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... 

Exxon s Flexsorb SE solvents achieve high hydrogen sulfide selectivity by virtue of their molecular structure. These solvents are sterically hindered secondary amines. A bulky molecule is used to shield the available hydrogen radical on the nitrogen atom and prevent the insertion of carbon dioxide. The reaction with hydrogen sulfide is not sensitive to the amine s structure, so the steric hinderance affords higher hydrogen sulfide selectivity. 

Furan is readily hydrogenated, hence it is a source of commercial tetrahydrofuran (THF). Reaction with hydrogen sulfide over alumina produces thiophene. A recent patent describes a catalyst based on cobalt and molybdenum oxides supported on alumina for this reaction (105). Furan undergoes the Diels-Alder reaction with strong dienophiles. Hydrogenation of the product resulting from reaction with maleic anhydride, followed by hydrolysis and neutralization gives a herbicide, Endothall. 

The amine 196 upon reaction with hydrogen sulfide in dimethylsulfoxide (DMSO) in the presence of base at 25-50 °C afforded the thiazine 197, allyl(2-mercaptopropyl)amine 198, and 3,7-dimethylperhydro[l,2,5]dithiazepine 199 in 10-17%, 2-31%, and 1-50% yields, respectively (Scheme 43) <2000RJC1243>. The formation of 199 is assumed via thiol 198, which reacted with a second hydrogen sulfide molecule to give dithiol 200. Subsequent oxidation of200 resulted in 199. In an alternative mechanistic pathway, the amine 196 can form the intermediate 201, which could cyclize to give 199. 

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