SODIUM CYANIDE (PRUSSIATE SODA)

Hydrogen cyanide is a highly toxic clear to pale blue liquid or gas with the odor of bitter almonds. It melts at -14 C and boils at 25.6 C. It is miscible in water or ethanol and is slightly soluble in ether. Its water solution, called hydrocyanic acid, is a weak acid. Hydrogen cyanide is mainly obtained by the reaction of ammonia with carbon monoxide (Andrussow process) or with natural gas (methane) in the presence of rhodium/platinum catalyst at approximately 1100 C. Very short contact time (milliseconds) is required to obtain the optimum yield and consequently a high operating temperature is required to reach equilibrium. It can be prepared also by the reaction of cyanide salts, e.g., calcium cyanide, with a strong acid (sulfuric acid). Hydrogen cyanide is obtained as a by-product from acrylonitrile production. But the portion is small. It is used as a fumigant in agriculture. The principal use of hydrogen cyanide is in the manufacturing of acrylates, synthetic fibers (as a starting material for nylon 66), plastics and cyanide salts, especially sodium cyanide to extract gold from ore. It is used in the manufacturing of organic chemicals; acrylonitrile, metal polishes, dyes, rodenticides, pesticides, synthetic fibers, plastics, and electroplating solutions. Cyanide salts are utilized in metal cleaning, tempering of steel, gardening, in ore-extracting processes, dyeing, printing and photography, Electroplating (gold and silver bath), various organic reactions (Organic cyanide and nitrile synthesis) manufacture of adiponitril for nylon production. Also used for production of monomers (e.g. acrylates) as well as in fumigants and pesticides. Sodium Cyanide is an extremely poisonous white deliquescent solid; soluble in water and liquid ammonia, and slightly soluble in ethanol; melting at 563 C, boiling at 1496 C; decomposes rapidly when standing. The aqueous solutions are strongly alkaline due to salt hydrolysis. This compound is extremely poisonous due to its reaction with iron in the blood, so blocking oxygen into the tissues of the body. It is prepared by absorbing hydrogen cyanide in caustic soda or liquid soda ash. It is used in extracting gold- and silver-ores, in electroplating baths, in polishing metals, in photographic processes, and in fumigating storage areas, soils and animals. It is also used in manufacturing chemicals; hydrocyanic acid, other cyanides, dyes, pigments, nylon intermediates, insecticides and rodenticides.