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C2H6NC
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C2H6NC + CH3COCI --> C2H5NC(COCH3)Cl —~HCI + C2H6NH3 + CH3CO•CO2H. This view was confirmed by J. See also:Wade (Journ. Chem. See also:Soc., 1902, 81, p. 1596) who showed that the products obtained by the See also:action of alkyl iodides on the isonitriles in alcoholic See also:solution at See also:roe C. yield amine hydroidides and formic See also:acid when hydrolysed. Such a reaction can only take See also:place if the addition of the alkyl See also:group takes" place on the See also:nitrogen See also:atom of the isonitrile, from which it follows that the nitrogen atom must be trivalent and consequently the See also:carbon atom divalent. The reactions may probably be represented as follows: C2H6NC+C2H5I+4C2H6OH=C2H5NH2•HI+HCO2C2H5+2 (C2H5)2O, C2H6NC(+C2HSI)-3C2H6N(C2H5•I)C(+3C2H5OH) -(C2H5)2NH•HI+ H•CO2C2H5 + (C2H5)2O. The isonitriles dissolve See also:silver See also:cyanide readily, forming a soluble silver See also:salt (cf. KNC). At 200° C. the isonitriles are converted into nitrites. Constitution of Metallic Cyanides.—Considerable discussion has taken place as to the structure of the metallic cyanides, since See also:potassium cyanide and silver cyanide react with alkyl iodides to See also:form nitriles and isonitriles respectively, thus apparently pointing to the fact that these two compounds possess the formulae KCN. and AgNC. The metallic cyanides are analogous to the alkyl isocyanides, since they form soluble See also:double silver salts, and the fact that See also:ethyl ferrocyanide on See also:distillation yields ethyl isocyanide also points to their isocyanide structure. J. Wade (loc. cit.) explains
the formation of nitriles from potassium cyanide, and of isonitriles from silver cyanide by the See also:assumption that unstable addition products are formed, the nature of which depends on the relative See also:state of unsaturation of the carbon and nitrogen atoms under the varying conditions
:
KNC-KN:C(:C2H51) –)KI+C2HsCN,
AgNC -AgN(:C2HsI)C-AgI +C2H5NC;
that is, when the See also:metal is highly electro-See also:positive the carbon atom is the more unsaturated, the addition takes place on the carbon atom, and nitriles are produced. The same type of reaction occurs when the metal is relatively electro-positive to the added See also:radical, for example, with ethyl isocyanide and acetyl chloride (see above) ; compare also AgNC --AgN(:Cl•000H3)C -->AgCl+CHa000N. On the other See also:hand, when there is but little electro-chemical difference between the radical of the cyanide and that of the reacting See also:compound then the nitrogen atom is the more unsaturated See also:element and isonitriles are produced. This explanation also accounts for the formation of nitriles by the diazo reaction, thus
:
C6H1N2CI+CuNC–4CuN:C•CI•N2•C,HS~CuCl•}• N :C•N2•CoH6- >C6HsCN+N2.
Detection.—The metallic cyanides may be detected by adding ferrous sulphate, ferric chloride, and hydrochloric acid to their solution, when a precipitate of.Prussian See also:blue is produced; if the See also:original solution contains See also:free acid it must be neutralized by See also:caustic potash before the reagents are added. As an alternative test the cyanide may be decomposed by dilute hydrochloric acid, and the liberated hydrocyanic acid absorbed in a little yellow ammonium sulphide. The excess of reagent is removed by evaporation and a small quantity of a ferric salt added, when a deep red See also:colour is produced. Silver nitrate gives a See also: Robine and M. Lengler, The Cyanide See also:Industry, 1906 (Eng. trans. by J. A. Le Clerc) ; W. Bertelsmann, See also:Die Technologie der Cyanverbindungen,1906. See also:Pharmacology, See also:Therapeutics and See also:Toxicology of Hydrocyanic Acid.—The pharmacopoeial preparations of this acid are a 2% solution, which is given in doses of from two to six minims, the tinctura chloroformi et morphinae composita, which contains a See also:half-See also:minim of this solution in each ten minims, and the aqua laurocerasi, which owes its virtues to the presence of this acid, and is of inconstant strength, besides being superfluous. The acid is also the active ingredient of the preparations of Virginian See also:Prune, to which the same strictures apply. The See also:simple cyanides See also:share the properties of the acid, except those of See also:platinum and See also:iron. With these exceptions, the simple cyanides are readily decomposed even by carbonic acid, free prussic acid being liberated. The double cyanides are innocuous. Hydrocyanic acid is a protoplasmic See also:poison, directly lethal to all living tissues, whether in a plant or an See also:animal. It is by no means the most powerful poison known, for such an See also:alkaloid as pseud-aconitine, which is lethal in dose of about 1/200 of a See also:grain, is some hundreds of times more toxic, but prussic acid is by far the most rapid poison known, a single inhalation of it producing absolutely instantaneous See also:death. The acid is capable of passing through the unbroken skin, where-upon it instantly paralyses the sensory nerves. It is very rapidly absorbed from raw surfaces and may thereby cause fatal consequences. It is naturally an antiseptic. The therapeutic applications of the See also:drug are based entirely upon its anaesthetic or See also:anodyne See also:power. A lotion containing ten minims of the dilute acid to an See also:ounce of See also:water and See also:glycerin will relieve itching due to any cause; and is useful in some forms of See also:neuralgia. It must never be employed when the skin is abraded. The diluted acid is used internally to relieve vomiting or gastric See also:pain. It is also added to cough mixtures, when the cough is of the dry, painful See also:kind, which serves no purpose, as nothing is expectorated. Such a cough is relieved by the sedative action on the central See also:nervous See also:system. Toxicology.—Instantaneous death results from taking the pure acid. The diluted form, in toxic quantities, will cause symptoms usually within a few seconds. The patient is quite unconscious, the eyes are motionless, the pupils dilated, the skin See also:cold and moist, the limbs relaxed, the See also:pulse is slow and barely perceptible, the respirations very slow and convulsive. See also:Post mortem, the See also:body is livid, and the See also:blood very dark. There may be an odour of prussic acid, but this soon disappears. Treatment is only rarely of use, owing to the rapidity of the toxic action. The patient who survives half-an-See also:hour will probably recover, as the volatile acid is rapidly excreted by the lungs. The drug kills by paralysing the nervous arrangements of the See also:heart and respiration. The appropriate drug is therefore atropine, which stimulates the respiration and prevents the See also:paralysis of the heart. One-fiftieth of a grain must be immediately injected subcutaneously. The See also:stomach must be washed out and large doses of See also:emetics given as soon as possible. Every second is of consequence. See also:Ammonia should be given by inhalation, and artificial respiration must never be forgotten, as by it the paralysed breathing may be compensated for and the poison excreted. The use of chemical antidotes, such as iron salts, is futile, as the drug has escaped into the blood from the stomach See also:long before they can be administered. Additional information and CommentsThere are no comments yet for this article.
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