Ammonium Sulfide Reagent

C. Ammonium Sulfide Reagent is prepd by mixing 1 volume of (NH4)2S with I vol of alcohol... 

Ethyl -aminobenzoate has been prepared by the esterification of p-aminobcnzoic acid1 and by the reduction of ethyl /i-nitrobenzoate with ammonium sulfide.2 Although commer-dally the reagent used is usually iron and water in presence of a little acid, in the laboratory the catalytic reduction as described in the procedure is by far the most convenient. 

This is by far the most important reaction of tetrazolium salts and accounts for the bulk of their many applications. A large variety of reagents can reduce tetrazolium salts, e.g., 53 to formazans, e.g., 51. Ascorbic acid, hydrazine, and hydroxylamine have been recommended for the preparation of formazans from tetrazolium salts.245 Stronger reducing agents such as ammonium sulfide, sodium amalgam, sodium dithionite, and catalytic hydrogenation can further reduce the formazans to the amidrazones, e.g.,... 

Nickel may he measured quantitatively hy several microanalytical gravimetric methods that include (l)formation of a red precipitate with dimethyl-glyoxime, (2) precipitation as a hlack sulfide with ammonium sulfide, (3) precipitating as a complex cyanide hy treating with alkali cyanide and bromine, and (4) precipitation as a yellow complex hy treating an ammoniacal solution of nickel with dicyandiamide sulfate (Grossman s reagent), followed hy the addition of potassium hydroxide. All of these methods can separate nickel from cobalt in solution. 

Partial reduction of aromatic polynitro compounds leads to nitro amines. The most successful reagents are the alkali metal or ammonium sulfides in aqueous alcoholIn some instances, sodium bicarbonate combined with sodium sulfide gives better results because of the formation of sodium hydrosulfide, which is believed to be the main reducing agent. Also, aqueous methanol is preferred to aqueous ethanol. Nitro compounds that are sparingly soluble in alcohol solutions may be reduced by hydrogen sulfide in pyridine solution. ... 

H). The use of sodium borohydride in the presence of platinum, palladium or Raney nickel [96] has been shown to give greater than 50% yields of benzimidazole )V-oxides, but even this reagent is capable of reducing a nitro group to amino, and combined with product loss on work-up, yields of the Af-oxides are often disappointing [97]. Sulfide reduction procedures (c.g. ammonium sulfide) seem better for 1-substituted benzimidazole 3-oxides than for benzimidazole 1-oxides [88, 92]. 

Additional work with ammonium sulfide has shown that it is a useful reagent for the hydrogenolysis of selenides obtained as by-products in the selenim dioxide dehydrogenation of 3-keto-A -steroids to the corresponding -ketones. 

Other reagents which can effect reduction of furoxans include iodide ion,83,446 sulfur dioxide,247,279 and ammonium sulfide.196... 

There are several complications endemic in this system. First, as was common experience from qualitative analysis with arsenic or tin, reagents of either oxidation state, with an excess of yellow ammonium sulfide, give the same higher oxidation state ... 

The detection of cations on chromatoplates is performed by spraying the solutions of the detection reagents at an appropriate concentration level, followed by visualization of the separated zones. The spraying reagents used as detectors include, 0.04-1 % dithizone in chloroform or carbon tetrachloride, 1% ethanolic solution of dimethylglyoxime, 1% aqueous solution of potassium ferrocyanide, 1% aqueous aluminon containing sufficient amount of ammonium acetate, 1% alcoholic solution of alizarine Red S, freshly prepared 0.1% solution of stannous chloride in 2 M HCl, hydrogen sulfide gas, aqueous saturated solution of ammonium sulfide, aqueous solution of ammonium thiocyanate and dilute solutions of diphenylcarbazide, p-nitroso-yV,A -dimethylaniline and sodium rhodizonate. 

All reagents were of analytical grade (Strem Chemical Company) and used without further purification. Silver powder (0.0545 g, 0.505 mmol), arsenic(II) sulfide (0.0155 g, 0.0724 mmol), and ammonium sulfide (0.100 mL, 40 wt%) are added to a quartz ampoule (7 mm o.d., 5 mm i.d.) approximately 9 cm long inside a glovebox filled with an argon atmosphere. The quartz ampoule... 

Thallous sulfide paper is prepared by bathing filter paper (S S 589 or Whatman 42) in 0.5 % solution of thallous carbonate or acetate for several minutes. The liquid is allowed to drain off and the paper is dried in a blast of heated air. Thallous sulfide is deposited by placing the paper across a beaker containing ammonium sulfide solution warmed to 80° C. The conversion to thallous sulfide is rapid the paper turns perfectly black on the side exposed to the fumes. Cut into strips, it is ready for immediate use. It is best always to use freshly prepared reagent paper when testing for sulfur. The paper deteriorates on standing because the sulfide is partially oxidized. 

Procedure. A drop of the ammoniacal test solution, in a micro crucible, is treated with a drop of colorless ammonium sulfide and, after two minutes, is acidified with several drops of 2 iV sulfuric or hydrochloric acid. A drop of the crucible contents is placed on filter paper, allowed to soak in, and then spotted with the reagent solution. A green ring around the central dark stain of sulfides indicates the presence of zinc. 

Attempts to use colorless ammonium sulfide (no added free sulfur) have been unsuccessful, as the yields of amide are always lower than with the polysulfide reagent, and mixtures of by-products such as diaryl-thiophenes and hydrocarbons predominate among the products isolated. 

The limitations placed upon the scale of preparative reactions in sealed glass tubes have led to attempts to carry out the Willgerodt reaction in a lead-lined autoclave, with disappointing results. Unfortunately, in these experiments a reagent containing only colorless ammonium sulfide instead of anunohium polysulfide was used. The colorless reagent is known... 

Miscellaneous Reactions. Sodium bisulfite adds to acetaldehyde to form a white crystalline addition compound, insoluble in ethyl alcohol and ether. This bisulfite addition compound is frequendy used to isolate and purify acetaldehyde, which may be regenerated with dilute acid. Hydrocyanic acid adds to acetaldehyde in the presence of an alkaU catalyst to form cyanohydrin the cyanohydrin may also be prepared from sodium cyanide and the bisulfite addition compound. Acrylonittile [107-13-1] (qv) can be made from acetaldehyde and hydrocyanic acid by heating the cyanohydrin that is formed to 600—700°C (77). Alanine [302-72-7] can be prepared by the reaction of an ammonium salt and an alkaU metal cyanide with acetaldehyde this is a general method for the preparation of a-amino acids called the Strecker amino acids synthesis. Grignard reagents add readily to acetaldehyde, the final product being a secondary alcohol. Thioacetaldehyde [2765-04-0] is formed by reaction of acetaldehyde with hydrogen sulfide thioacetaldehyde polymerizes readily to the trimer. 

The metal and ammonium salts of dithiophosphinic acids tend to exhibit far greater stability with respect to this thermal decomposition reaction, and consequently these acids are often prepared directly in their salt form for convenience and ease of handling. Alkali-metal dithiophosphinates are accessible from the reaction of diphosphine disulfides with alkali-metal sulfides (Equation 22) or from the reaction of alkali-metal diorganophosphides with two equivalents of elemental sulfur (Equation 23). Alternatively, they can be prepared directly from the parent dithiophosphinic acid on treatment with an alkali-metal hydroxide or alkali-metal organo reagent. Reaction of secondary phosphines with elemental sulfur in dilute ammonia solution gives the dithiophosphinic acid ammonium salts (Equation 24). 

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