CUPROUS CYANIDE

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. Copper compounds form a protective barrier on the plant surface and thereby prevent fungi from entering the plant host. The fungicidal effect of copper compounds as non-systemic fungicides are such as bordeaux mixture, cupric hydroxide, copper arsenate, copper carbonate, cuprous oxide, copper-8-quinolinolate, copper oleate, copper sulfate, or copper oxychloride. Another important biological application of copper compounds, such as copper sulfide is as an antifouling agent in paints.