Hydrogen sulfide, solution preparation

Hydrogen sulfide, H2S prepare a saturated aqueous solution. 

The procedure should be carried out in an efficient fume hood. A solution of ammonium hydrogen sulfide is prepared by saturating a concentrated ammonium hydroxide solution with... 

Mercaptopyrazine (151a) is best prepared by the action of sodium hydrogen sulfide on chloropyrazine in dimethylformamide.147 It decomposes on heating with evolution of hydrogen sulfide and formation of di-2-pyrazinyl sulfide. The latter compound is also obtained together with mercaptopyrazine on treatment of chloropyrazine with aqueous potassium hydrogen sulfide solution. Comparison of the... 

Lead Paper. This reagent for hydrogen sulfide, is prepared by soaking filter paper in a solution containing 5 grams of lead nitrate per liter, and drying in air free from H2S. Instead of this paper, one can use paper moistened widi ferrous sulfate or lead acetate solution. 

Many quinoxaline-2,3-dithiones have been prepared from the corresponding 2,3-dichloroquinoxalines by heating under reflux with excess of aqueous potassium hydrogen sulfide solution. The alkali-soluble product on acidification with acetic acid yields the quinoxaline-2,3-dithione. When 2,3-dichloroquinoxaline is treated with two molecular proportions of thiourea in ethanolic solution, S-2-(3-mercaptoquinoxalinyl)-isothiouronium chloride is formed in almost quantitative yield. This on treatment with boiling aqueous sodium hydroxide solution yields quinoxaline-2,3-dithione (15). Substituted quinoxaline-2,3-dithiones have also been prepared by this method. Quinoxaline-2,3-dithione has also been prepared from quinoxaline-2,3-dione by treatment with phosphorus pentasulfide in pyridine, thus avoiding the necessity of first forming the dichloroquinoxaline from the dione. ... 

Chrysean (10), prepared by bubbling hydrogen sulfide through a sodium cyanide solution, was among the first described thiazoles (53-57). Other 5-aminothiazoles are also most easily prepared bv hetero-cyclization (see Chapter 11. Section II.5.A). 

Hydroiodic acid, the colorless solution formed when hydrogen iodide gas dissolves in water, is prepared by reaction of iodine with hydrogen sulfide or hydrazine or by an electrolytic method. Typically commercial hydroiodic acid contains 40—55% HI. Hydroiodic acid is used in the preparation of iodides and many organic iodo compounds. 

Nickel sulfide, NiS, can be prepared by the fusion of nickel powder with molten sulfur or by precipitation usiag hydrogen sulfide treatment of a buffered solution of a nickel(II) salt. The behavior of nickel sulfides ia the pure state and ia mixtures with other sulfides is of iaterest ia the recovery of nickel from ores, ia the high temperature sulfide corrosion of nickel alloys, and ia the behavior of nickel-containing catalysts. 

The H2S sulfanes are the subject of several reviews (129,133). Except for hydrogen sulfide these have no practical utiUty. Sodium tetrasulfide [12034-39-8] is available commercially as a 40 wt % aqueous solution and is used to dehair hides in taimeries, as an ore flotation agent, in the preparation of sulfur dyes (qv), and for metal sulfide finishes (see Leather Mineral recovery and processing). 

Arsenic pentasulfide (arsenic(V) sulfide), As S q, is stable in air up to 95°C, but at higher temperatures begins to dissociate into arsenous sulfide and sulfur. It is prepared by the fusion of arsenic with sulfur foUowed by extraction with ammonia and reprecipitation at low temperatures by addition of hydrochloric acid. Arsenic pentasulfide is precipitated at low temperatures from strongly acidic arsenate solutions by a rapid stream of hydrogen sulfide. It is hydrolyzed by boiling with water, yielding arsenous acid and sulfur. Salts derived from a number of thioarsenic acids are formed from arsenic pentasulfide and alkaH metal sulfides. 

Heretofore, no economical method for preparing pure phytic acid was known. The classical method was to dissolve calcium phytate in an acid such as hydrochloric acid, and then add a solution of a copper salt, such as copper sulfate to precipitate copper phytate. The latter was suspended in water and treated with hydrogen sulfide, which formed insoluble copper sulfide and released phytic acid to the solution. After removing the copper sulfide by filtration, the filtrate was concentrated to yield phytic acid as a syrup. 

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. 

Ammonium pentasulfide is usually prepared according to Eq. (17) by suspending elemental sulfur in aqueous ammonia (35%) and bubbling hydrogen sulfide into the solution [20, 31, 32] ... 

The parent hexathiaadamantane (185) is obtained preparatively when a solution of formic acid and hydrochloric acid in nitrobenzene is allowed to stand for several weeks in a hydrogen sulfide atmosphere the product which separated is almost insoluble in all common solvents and purification presents a problem. Only large volumes of dimethyl sulfoxide at reflux serve for recrystallization.224 The reaction of thioacetic acid with formic acid in the presence of zinc chloride gives tetramethyl-(186), monomethyl-, dimethyl-and trimethylhexathiaadamantane derivatives (187).225 Other variations include the reaction of thioacetic acid with a /i-diketone,226 and the use of boron trifluoride227 or aluminum chloride as a catalyst.228... 

Bagley and coworkers have described the preparation of primary thioamides by treatment of nitriles with ammonium sulfide in methanol solution (Scheme 6.139) [276], While the reactions with electron-deficient aromatic nitriles proceeded at room temperature, other aromatic and aliphatic nitriles required microwave heating at 80-130 °C for 15-30 min to furnish the thioamides in moderate to high yields. This protocol avoids the use of hydrogen sulfide gas under high pressure, proceeds in the absence of base, and usually provides thioamides without the need for chromatographic purification. 

A solution of 64.9 g. (I mole) of 86.5% potassium hydroxide (Note I) in 28 ml. of water is cooled in an ice bath, saturated with hydrogen sulfide, and flushed with nitrogen to ensure complete removal of excess hydrogen sulfide (Notes 2 and 3). The freshly prepared potassium hydrosulfide solution is diluted with 117 ml. of water and stirred under nitrogen at 55-60°. Then 95.3 g. (0.5 mole) of finely ground tosyl chloride (Note 3) is introduced in small portions at a uniform rate so that the reaction temperature is maintained at 55-60° (Note 2). A mildly exothermic reaction ensues, and the solution becomes intensely yellow. After about 90 g. of tosyl chloride has been introduced, the yellow color disappears, and the dissolution of the chloride ceases. The reaction mixture is rapidly filtered with suction through a warmed funnel, and the filtrate is cooled several hours at 0-5°. The crystals of potassium... 

There is a long history of the preparation of explosive solids or oils from interaction of diazonium salts with solutions of various sulfides and related derivatives. Such products have arisen from benzene- and toluene-diazonium salts with hydrogen, ammonium, or sodium sulfides [1,5] 2- or 3-chlorobenzene-, 4-chloro-2-methylbenzene-, 2- or 4-nitrobenzene- or 1- or 2-naphthalene-diazonium solutions with hydrogen sulfide, sodium hydrogen sulfide or sodium mono-, di- or poly-sulfides [l]-[4,7], 4-Bromobenzenediazonium solutions gave with hydrogen sulfide at -5°C a product which exploded under water at 0°C [2], and every addition of a drop of 3-chlorobenzenediazonium solution to sodium disulfide solution... 

Incorporation of n-Si in the mixed CdS-ZnS system results in electron flow from the n-Si to the CdS conduction band, resulting in greater utilization of solar radiation as well as superior electron-hole separation [162,163]. Under direct sunlight (25 mW/cm ), a suspension of n-Si/CdS-ZnS yields 15 mL/h/g of hydrogen from an aqueous sulfite/sulfide solution [162]. Hydrogen evolution of 35 mL/h/g has been recorded for CdS-ZnS (2 1 weight ratio) prepared by coprecipitation and then loaded with n-Si (1.4 - 1.6%) [163]. 

Ternary semiconductors of the I-III-VI groups (I = Cu, Ag III = Al, Ga, In VI = S, Se, Te) with a chalcopyrite structure have attracted attention as new functional materials for solar hydrogen production [164-167]. With the aim of capturing a larger fraction of solar light, solid solutions of two or more sulfides were prepared. A... 

The pure sulphide is obtained from its ore. Stibnite is separated from other ores by grinding and flotation. The ore is then heated to 550-600°C in a perforated vessel. The pure molten material is collected and cooled. It is also prepared by passing hydrogen sulfide into a solution of antimony trichloride ... 

Arsenic pentasulfide is prepared by precipitation from an acidic solution of orthoarsenic acid, H3ASO4, or arsenic pentachloride, AsCls or any other soluble As(V) salt by passing hydrogen sulfide. It may be also prepared by heating a mixture of arsenic and sulfur, extracting the fused mass with ammonia solution and reprecipitating arsenic pentasulfide at low temperature hy addition of HCl. 

The compound occurs in nature as mineral bismuthinite. It can be prepared in the laboratory by passing hydrogen sulfide into a solution of bismuth chloride or any soluble bismuth salt ... 

Cadmium sulfide may be prepared by precipitation from an aqueous solution of its soluble salts such as cadmium chloride or cadmium nitrate by passing hydrogen sulfide. The reactions may he carried out in acidic, neutral or alkaline solutions using various cadmium salts to obtain different crystal modifications as shown in the table below. 

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