Cyanogen chlorids

Cyanogen chloride, CICN. Colourless liquid, m.p. — C,b.p. 13 C(aqueousCN plusCl2). Linear molecule, polymerizes to cyanuric chloride (CICN),. Extremely poisonous. 

A solution of 0.40 mol of ethyllithium in about 350 ml of diethyl ether (see Chapter II, Exp. 1) was transferred into the flask, which previously had been filled with nitrogen. The solution was cooled to -50°C and a cold solution (-30°C) of 0.43 mol of propyne in 50 ml of dry diethyl ether was added at a rate such that the temperature could be kept below -20°C. A solution of 0.45 mol of cyanogen chloride in 100 ml of diethyl ether, cooled at about 0°C, was then added in... 

Compare the dipole moments of cyanogen bromide (BrC=N) and cyanogen chloride (C1C=N) Which IS larger" Why" What does this tell you about the electronegativity of the CN group" ... 

Removal of maleic and fumaric acids from the cmde malononitrile by fractional distillation is impractical because the boiling points differ only slightly. The impurities are therefore converted into high boiling compounds in a conventional reactor by means of a Diels-Alder reaction with a 1,3-diene. The volatile and nonvolatile by-products are finally removed by two vacuum distillations. The by-products are burned. The yield of malononitrile amounts to 66% based on cyanogen chloride or acetonitrile. 

Economic Aspects. Malononitrile of minimum 99% purity was available as a soHdifted melt for ca 30/kg in 1993 for ton quantities. Malononitrile is produced by Lon2a Ltd. (Swit2edand) using the cyanogen chloride process. 

Guanidines. Guanidines (10) were one of the first aniline derivatives used as accelerators. They are formed by reaction of two moles of an aromatic amine with one mole of cyanogen chloride. Diphenylguanidine (DPG) has enjoyed a resurgence ia demand as an activator for sulfenamides and a co-accelerator ia tire tread compounds which employ siUca fillers for low rolling resistance. Guanidines alone show too Htde activity to be extensively used as primary accelerators. There were no U.S. producers as of mid-1996. 

Cyanide destmction by alkaline chlorination is a widely used process. With alkaline chlorination, cyanide is first converted to cyanate with hypochlorite [7681-52-9] at a pH greater than 10. A high pH is required to prevent the formation of cyanogen chloride [506-77-4] which is toxic and may evolve in gaseous form at a lower pH. With additional hypochlorite, cyanate is then oxidized to bicarbonate, nitrogen gas, and chloride. The pH for this second stage is 7—9.5 (6). 

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. 

Cyanogen chloride and NaOH give the potentially useful sodium dicyanamide [1934-75-4] salt (14). 

The pH value is usually maintained above 9 to avoid formation of nitrogen trichloride. At lower pH values, aqueous solutions react with chlorine to form cyanogen chloride (52). 

Tetracyanome thane [24331-09-7] methanetetracarbonitdle, is prepared by heating silver tricyanomethanide [36603-81 -3] n.]ic id cyanogen chloride (42). 

It is a very strong cyanating agent eg, it converts chloride ion to cyanogen chloride [506-77-4]. 

On the large scale, cyanuric chloride is produced by the trimerization of cyanogen chloride. The cyanogen chloride is produced by chlorination of hydrogen cyanide and is trimerized by passing it over charcoal impregnated with an alkaline-earth metal chloride at a high temperature (250—480°C). 

Caution Since cyanogen chloride is highly toxic, the preparation and isolaiion of the sulfonyl cyanide should be condwted in a well-ventilated hood. 

When the benzenesulfinates were substituted with electron-withdrawing groups, e.g., p-nitro- and p-cyanobenzenesulfinate, the yields were slightly improved when the reaction time with cyanogen chloride was lengthened to 1 hour. 

Whereas sulfonyl halides have been known for a long time and, especially the chlorides, have become of great synthetic value, sulfonyl cyanides were unknown until 1968. They were first prepared by van Leusen and co-workers from the reaction of sulfonylmethylenephos-phoranes with nitrosyl chloride. The same group also investigated part of their chemistry. Since then, two more, completely different, methods of synthesis were published from sulfinates with cyanogen chloride,and by the oxidation of thiocyanates. ... 

Upper and lower respiratory Eluorine chlorine bromine ozone cyanogen chloride. ... 

Cyanogen chloride (Chlorine cyanide) CNCI Poisonous liquid or gas Vapour highly irritating and very toxic Colourless liquid with a strong irritating smell Boiling point 1 3°C Vapour density 2.1... 

Cyanogens Cyanogens Hydrogen cyanide Cyanogen chloride Cyanogen bromide Cyanogen iodide Acetonitrile Acrylic nitrile... 

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