词条 | Cyanogen halide | |
释义 |
A cyanogen halide is a molecule consisting of cyanide and a halogen. Cyanogen halides are chemically classified as pseudohalogens. The cyanogen halides are a group of chemically reactive compounds which contain a cyano group (-CN) attached to a halogen element, such as fluorine, chlorine, bromine or iodine. Cyanogen halides are colorless, volatile, lacrimatory (tear-producing) and highly poisonous compounds. ProductionHalogen cyanides can be obtained by the reaction of halogens with metal cyanides or the halogenation of hydrocyanic acid.[1][2] M = metal, X = halogen Cyanogen fluoride can be obtained by thermal decomposition of cyanuric fluoride. PropertiesHalogen cyanides are stable at normal pressure below 20 °C and in the absence of moisture or acids. In the presence of free halogens or Lewis acids[3] they easily polymerize to cyanuric halides, for example cyanogen chloride to cyanuric chloride. They are very toxic and tear-inducing (lachrymatory). Cyanogen chloride melts at -6 °C and boils at about 150 °C. Bromine cyanide melts at 52 °C and boils at 61 °C. Iodine cyanide sublimates at normal pressure.[1] Cyanogen fluoride boils at -46 °C and polymerizes at room temperature to cyanuric fluoride.[3] In some of their reactions they are resembling halogens.[4][3] The hydrolysis of cyanogen halides takes place in different ways depending on the electronegativity of the halogens and the resulting different polarity of the X-C bond.[5] (X = F, Cl) (X = Br, I) Cyanogen fluoride is a gas produced by heating cyanuric fluoride. Cyanogen chloride is a liquid produced by reacting chlorine with hydrocyanic acid. Biomedical Effects and Metabolism of cyanogen halidesCyanide is naturally present in human tissues in very small quantities. It is metabolized by rhodanese, a live enzyme at a rate of approximately 17 µg/kg*min. Rhodanese catalyzes the irreversible reaction forming thiocyanate from cyanide and sulfane which is non-toxic and can be excreted through the urine. Under normal conditions, availability of sulfane is the limiting factor which acts as a substrate for rhodanese. Sulfur can be administered therapeutically as sodium thiosulfate to accelerate the reaction. A lethal dose of cyanide is time-dependent because of the body’s ability to detoxify and excrete small amounts of cyanide through rhodanese-sulfate catalysis. If an amount of cyanide is absorbed slowly, rhodanese-sulfate may be able to biologically render it non-toxic through catalysis to thiosulfate whereas the same amount administered over a short period of time may be lethal.[6] UseHalogen cyans, in particular cyanogen chloride and cyanogen bromide, are important starting materials for the incorporation of the cyanogen group, the production of other carbonic acid derivatives and heterocycles.[7] It has been suggested that cyanogen chloride be used by the military as poison gas. Cyanogen bromide is a solid that is prepared by reacting bromine with hydrocyanic acid salts; it has been used as a chemical pesticide against insects and rodents and as a reagent for the study of protein structure.[8] Cyanogen halides have been found to act as electrolytes in liquid solvents, sulfur dioxide, arsenous chloride, and sulfuryl chloride. See also
References1. ^1 {{citation|surname1=C.R. Noller|title=Lehrbuch der Organischen Chemie|publisher=Springer-Verlag|page=335|isbn=978-3-642-87324-9|date=2013|language=German|url={{Google books|rsrOBgAAQBAJ||page=335}}}} {{DEFAULTSORT:Cyanogen Halide}}2. ^{{citation|title=Houben-Weyl Methods of Organic Chemistry Vol. VIII, 4th Edition Peroxides, Carbonic Acid Derivatives, Carboxylic Acids, Carboxylic Acid Derivatives|publisher=Georg Thieme Verlag|page=90|isbn=978-3-13-180534-8|date=2014|language=German|url={{Google books|w1KGAwAAQBAJ||page=90}}}} 3. ^Georg Brauer (Hrsg.), unter Mitarbeit von Marianne Baudler u. a.: Handbuch der Präparativen Anorganischen Chemie. 3., umgearbeitete Auflage. Band I, Ferdinand Enke, Stuttgart 1975, {{ISBN|3-432-02328-6}}, S. 227. 4. ^{{citation|title=Houben-Weyl Methods of Organic Chemistry Vol. VIII, 4th Edition Peroxides, Carbonic Acid Derivatives, Carboxylic Acids, Carboxylic Acid Derivatives|publisher=Georg Thieme Verlag|page=90|isbn=978-3-13-180534-8|date=2014|language=German|url={{Google books|w1KGAwAAQBAJ||page=90}}}} 5. ^spektrum.de: Halogencyane - Lexikon der Chemie - Spektrum der Wissenschaft, abgerufen am 22. Januar 2017. 6. ^{{ cite web | title = Iodine cyanide | url = https://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=10478 | work = PubChem | publisher = NIH | accessdate = 2012-04-27 }} 7. ^1 2 {{citation|title=Houben-Weyl Methods of Organic Chemistry Vol. E 4, 4th Edition Supplement Carbonic Acid Derivatives|publisher=Georg Thieme Verlag|page=915|isbn=3-13-181144-7|date=2014|language=German|url={{Google books|LCyGAwAAQBAJ||page=915}}}} 8. ^{{ cite encyclopedia | title = Cyanogen halide | encyclopedia = Encyclopædia Britannica | year = 2012 | url = http://www.britannica.com/EBchecked/topic/147758/cyanogen-halide | accessdate = 2012-04-27 }} 2 : Halides|Cyanides |
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