Cyanide persistence

This is not the case in most fires where some oi the intermediate produces, formed when large, complex molecules are broken up, persist. Examples are hydrogen cyanide from wool and silk, acrolein from vegetable oils, acetic acid from timber or paper, and carbon or carbon monoxide from the incomplete combustion of carbonaceous materials. As the fire develops and becomes hotter, many of these intermediates, which are often toxic, are destroyed—for example, hydrogen cyanide is decomposed at about 538°C (1000°F). 

Substances which have a deleterious effect on the taste and/or smell of the products for human consumption derived from the aquatic environment Toxic or persistent organic compounds of silicon Inorganic compounds of phosphorus and elemental phosphorus Non-persistent mineral oils and hydrocarbons of petroleum origin Cyanides, fluorides... 

Method A. Weigh out accurately about 3.5 g of potassium cyanide from a glass-stoppered weighing bottle, dissolve it in water and make up to 250 mL in a graduated flask. Shake well. Transfer 25.0 mL of this solution by means of a burette and NOT a pipette to a 250 mL conical flask, add 75 mL water, 5-6 mL 6M ammonia solution, and 2 mL 10 per cent potassium iodide solution. Place the flask on a sheet of black paper, and titrate with standard 0.1 M silver nitrate. Add the silver nitrate solution dropwise as soon as the yellow colour of silver iodide shows any signs of persisting. When one drop produces a permanent turbidity, the end-point has been reached. 

Phosgene will persist 5 min or longer in the open in the summer. Hydrogen cyanide, MW=27.02, may persist only a minute under the same circumstances. 

Volatile cyanides occur only occasionally in the atmosphere, due largely to emissions from plating plants, fumigation, and other special operations (Towill et al. 1978). Under normal conditions, cyanide has relatively low persistence in air, usually between 30 days and 1 year (Way 1981), although some atmospheric HCN may persist for up to 11 years (Marrs and Ballantyne 1987). Data are lacking on the distribution and transformation of cyanide in the atmosphere (Towill et al. 1978) and should be acquired. 

Cyanide has low persistence in the environment and is not accumulated or stored in any mammal studied. 

Drinking water of adults contained 150 mg CN/L, as KCN, for 2 weeks, followed by injection with radioselenium-75 and observed for 15 days Cyanide-treated rats excreted significantly more radioselenium in urine than did controls. Half-time persistence of radioselenium in treated group was 28 days vs. 38 days in controls 35... 

When the HCN contained 1-2 % mole of water the yields tended to increase exponentially with dose. This was due to the occurrence of a superimposed thermal reaction, which became faster as the radiation products accumulated and persisted after irradiation ceased. Hummel and Janssen attributed it to the hydrolysis of imino and cyano groups on the polymer chain. They suggested that the ammonia generated in this process reacted with HCN to form cyanide ions, which then initiated the polymerisation. 

While the cuprous cyanide solution is warmed gently (to 60°-70°) on the water bath, a solution of p-tolyldiazonium chloride is prepared as follows Heat 20 g. of p-toluidine with a mixture of 50 g. of concentrated hydrochloric acid and 150 c.c. of water until dissolution is complete. Immerse the solution in ice-water and stir vigorously with a glass rod so that the toluidine hydrochloride separates as far as possible in a microcrystalline form. Then cool the mixture in ice and diazotise with a solution of 16 g. of sodium nitrite in 80 c.c. of water, added until the nitrous acid test with potassium iodide-starch paper persists. The diazonium chloride solution so obtained is poured during the course of about ten minutes into the warm cuprous cyanide solution, which is meanwhile shaken frequently. After the diazo-solution has been added the reaction mixture is heated under an air condenser on the water bath fox a further quarter of an hour, and then the toluic nitrile is separated by distillation with steam (fume chamber, HCN ). The nitrile (which passes over as a yellowish oil) is extracted from the distillate with ether, the p-cresol produced as a by-product is removed by shaking the ethereal extract twice with 2 A-sodium hydroxide solution, the ether is evaporated,... 

Most reported cases of chronic cyanide poisoning involve workers with a mixture of repeated acute or subacute exposures, making it unclear whether symptoms resulted simply from multiple acute exposures with acute intoxication or from prolonged, chronic exposure. Some symptoms persisted after cessation of such exposures, perhaps because of the effect of anoxia from inhibition of cytochrome oxidase. Symptoms from chronic exposure are similar to those reported after acute exposures, such as weakness, nausea, headache, and vertigo. A study of 36 former workers in a silver reclaiming facility chronically exposed to cyanide demonstrated some residual symptoms 7 or more months after cessation of exposure frequent headache, eye irritation, easy fatigue, loss of appetite, and epistaxis occurred in at least 30% of these workers. ... 

Brombenzyl cyanide (CA)—also called a-bromobenzyl cyanide, o-bromotolunltrlle, bromobenzylnitrlle, and a-bromophenylaceto-nitrile--was the most powerful lacrlmator used In World War I (see Table 4-1). It was Introduced by the French army and adopted as the standard U.S. lacrlmator In 1918. It was temporarily abandoned because of its reactions with metal and instability in storage.3 10 Interest in it revived when a need arose for a chemical that was more persistent than CS and CN in enclosed areas, such as rooms and earthen tunnels. In this connection, vapors of CA from ground contamination are lacrlmatory for 15-30 d.6... 

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