Cyanides compounds

Cyanide compounds are classified as either simple or complex. It is usually necessary to decompose complex cyanides by an acid reflux. The cyanide is then distilled into sodium hydroxide to remove compounds that would interfere in analysis. Extreme care should be taken during the distillation as toxic hydrogen cyanide is generated. The cyanide in the alkaline distillate can then be measured potentiometricaHy with an ion-selective electrode. Alternatively, the cyanide can be determined colorimetricaHy. It is converted to cyanogen chloride by reaction with chloramine-T at pH <8. The CNCl then reacts with a pyridine barbituric acid reagent to form a red-blue dye. 

Cyanides are dangerously toxic materials that can cause instantaneous death. They occur in a number of industrial situations but are commonly associated with plating operations, and sludges and baths from such sources. Cyanide is extremely soluble and many cyanide compounds, when mixed with acid, release deadly hydrogen cyanide gas. Cyanide is sometimes formed during the combustion of various nitrile, cyanohydrin, and methacrylate compounds. Cyanides (CN ) are commonly treated by chlorine oxidation to the less toxic cyanate (CNO ) form, then acid hydrolyzed to COj and N. Obviously, care should be taken that the cyanide oxidation is complete prior to acid hydrolysis of the cyanate. 

Cyanide Compounds - X CN- where X = H or any other group where a formal dissociation may occur. For example KCN or Ca(CN). ... 

In the blast furnace, the reaction of the nitrogen in the blast with coke leads to the formation of poisonous chemicals such as hydrogen cyanide and cyanogens, and each cubic meter of the blast furnace gas contains from 200 to 2000 mg of these compounds. The blast furnace gas is scrubbed with water in the dust collection system the cyanide compounds dissolve in the water, which is then discharged after the compounds have been destroyed. Another poisonous emission in blast furnace operations is hydrogen sulfide. The sulfur present in the coke is converted into calcium sulfide in the slag, the water-quenching of... 

The use of plant extracts for insect control dates into antiquity the use of Paris green as an insecticide for control of the Colorado potato beetle in 1867 probably marks the beginning of the modern era of chemical control of injurious insects. The development of lead arsenate followed later in the nineteenth century for gypsy moth control. The commercial production of nicotine insecticides, the production of calcium arsenate at the time of the first world war, and the use of fluorine, arsenical, and cyanide compounds, as well as other inorganic chemicals for insect control, were important steps in pest control. These chemicals were applied largely by dilute high pressure sprays or dusts. 

Dunbar, K. R. Heintz, R. A. Chemistry of Transition Metal Cyanide Compounds Modern Perspectives. In Progress in Inorganic Chemistry, Karlin, K. D., Ed. J. Wiley New York, 1997, Vol. 45, pp 283-391. 

Cyanide compounds are useful to society in terms of their key role in synthetic and industrial processes, for certain fumigation and agricultural uses, and for some therapeutic applications (Ballantyne and Marrs 1987). Cyanides are present in effluents from iron and steel processing plants, petroleum refineries, and metal-plating plants, and constitute a hazard to aquatic ecosystems in certain waste-receiving waters (Smith et al. 1979) and to livestock (USEPA 1980 Towill et al. 1978). Cyanide serves no useful purpose in the human body, yet it is present in our food, air, and water (Becker 1985). 

Thiocyanate metabolites resulting from the transulfuration process are about 120 times less toxic than the parent cyanide compound. 

Cyanide compounds have been prescribed by physicians for treatment of hypertension and cancer (Sprine et al. 1982). Sodium nitroprusside (Na2Fe(CN)5NO 2H20) was widely used for more than 30 years to treat severe hypertension and to minimize bleeding during surgery (Solomon-son 1981 Vesey 1987). Laetrile, an extract of ground apricot kernels, has been used for cancer chemotherapy and, in deliberate high intakes, as an attempted suicide vehicle (Gee 1987). 

Numerous biological and abiotic factors are known to modify the biocidal properties of free cyanide, including water pH, temperature, and oxygen content life stage, condition, and species assayed previous exposure to cyanide compounds presence of other chemicals and initial dose tested. There is general agreement that ... 

Organic cyanide compounds, or nitriles, have been implicated in numerous human fatalities and signs of poisoning — especially acetonitrile, acrylonitrile, acetone cyanohydrin, malonitrile, and succinonitrile. Nitriles hydrolyze to carboxylic acid and ammonia in either basic or acidic solutions. Mice (Mus sp.) given lethal doses of various nitriles had elevated cyanide concentrations in liver and brain the major acute toxicity of nitriles is CN release by liver processes (Willhite and Smith 1981). In general, alkylnitriles release CN much less readily than aryl alkylnitriles, and this may account for their comparatively low toxicity (Davis 1981). 

Brimer, L. 1988. Determination of cyanide and cyanogenic compounds in biological systems. Pages 177-200 in D. Evered and S. Harnett (eds.). Cyanide compounds in biology. Ciba Foundation Symposium 140. John Wiley, Chichester. 

Harnett (eds.). Cyanide Compounds in Biology. Ciba Found. Sympos. 140. John Wiley, Chichester. Knudson, T. 1990. Gold mining s deadly life blood. Sacramento (California) Bee (newspaper), March 21, 1990. Kovacs, T.G. and G. Leduc. 1982a. Sublethal toxicity of cyanide to rainbow trout (Salmo gairdneri) at different temperatures. Canad. Jour Fish. Aquat. Sci. 39 1389-1395. 

Nonomura, M. and T. Hobo. 1989. Ion chromatographic determination of cyanide compounds by chloramine-T and conductivity measurement. Jour. Chromatogr. 465 395-401. 

Abstract Investigation of the process of cyanide compounds destruction under... 

Plasma-chemical sample preparation allows breaking-up of cyanide compounds to non-toxic forms, which may be used for purification of technological solutions and galvanic production wastewaters, posing hazard to people s health in the event they are purposely used by terrorists. 

Two- and Three-Dimensional Fe(L)x[M(CN)4] Hofmann-Like Cyanide Compounds... 

T4. Toepfer, E. W., Polansky, M. M., and Hewston, E. M., Fluorometric determination of pyridoxamine by conversion to pyridoxal cyanide compound. Anal. Biochem. 2, 463-469 (1961). 

Hydrogen cyanide (HCN) is a colorless, rapidly acting, highly poisonous gas or liquid that has an odor of bitter almonds. Most HCN is used as an intermediate at the site of production. Major uses include the manufacture of nylons, plastics, and fumigants. Exposures to HCN may occur in industrial situations as well as from cigarette smoke, combustion products, and naturally occurring cyanide compounds in foods. Sodium nitroprusside (Na2[Fe(CN)5 N0]-2H20), which has been used as an antihypertensive in humans, breaks down into nonionized HCN. 

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