Alkali sulfides, reducing agents

The parent compound is quite sensitive to alkali and reducing agents. Aqueous alkali decomposes it to ammonia, hydrogen sulfide and sulfur. Substituents at the 3- and 5-positions... 

Nitro-filter cloths are composed of cellulose nitrate, which is an ester of cellulose. Any chemical compound that will saponify the ester will destroy the cloth. Caustic soda or potash in strengths of 2% at 70° C or over alkali sulfides, polysulfides and sulfohydrates or mixtures of ethyl alcohol and ether, ethyl, amyl and butyl acetates, pyridine, ferrous sulfates, and other reducing agents are detrimental to the cloth. 

The conventional sulfur dye powder is made into a paste with a small amount of soft water and an alkali-stable wetting agent. Boiling for a few minutes in a strong solution of sodium sulfide reduces the dye. The dissolved dye is diluted to the required dyebath volume. When dyeing pale shades, the final bath should contain at least 5 g/L sodium sulfide (60%), irrespective of the amount used to dissolve the dye. 

In its solutions in liquid NIL. cesium is like the other alkali metals, a powerful reducing agent, so that in such solutions, titrations of cesium poly sulfide with cesium are made by eleclrumeiric methods. The solubility of cesium salts in liquid NHi increases markedly with the radius of an anion (the chloride. CsCI. 0.0227 moles per kg. the bromide. CsBr, 0.215 moles per kg. and the iodide. Csl. 5.84 moles per kg), though the values are less than for the corresponding rubidium compounds. 

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). 

Alkali metal polysulfides are added to stabilize alkaline sulfur dye liquors against atmospheric oxygen. This is common for Hydron Blue, especially on the winch beck. An excess of sulfide and reducing agent in the wastewater has to be avoided therefore, low-sulfide dyeing methodes were introduced [71],... 

It should be mentioned incidental that alkali metal sulfides can also be used as reducing agents for this purpose if they happen to be available cheap. ... 

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. ... 

Citric acid is incompatible with potassium tartrate, alkali and alkaline earth carbonates and bicarbonates, acetates, and sulfides. Incompatibilities also include oxidizing agents, bases, reducing agents, and nitrates. It is potentially explosive in combination with metal nitrates. On storage, sucrose may crystallize from syrups in the presence of citric acid. 

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