Ammonium hydrogen sulfide, reducing agent

Denitration can be effected by chemical reducing agents (134)- For monomolecular nitrates, reductive denitration with hydrogen and Raney nickel (135) is preferable. Ammonium hydrogen sulfide effectively denitrates the nitrated polysaccharides. 

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.,... 

Reducing agents commonly employed are iron, tin, or SnCI2 in hydrochloric acid and ammonium or alkali-metal sulfides catalytic hydrogenation and electrolytic reduction also are employed (see Section 23-12B). 

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. ... 

AMMONIUM MONOSULFIDE (12124-99-1) NH4 HS (aqueous) (NH4)2S (anhydrous) The anhydrous material is pyrophoric in air it decomposes at room temperature, releasing ammonia and toxic and flammable hydrogen sulfide gas. Stable below 32°F/0°C. The commercial product [a 40% solution in water (NH4HS)] is stable. The aqueous solution is a reducing agent. Violent reaction with strong oxidizers... 

---