Iodine cyanide, reaction

In his first experiment (1987) Zewail studied the unimolecular disintegration of iodine cyanide into iodine atom and cyano radical ICN I + CN. They managed to observe a transition state corresponding to the I-C bond breaking. The whole reaction was over in 200 fs. 

Micellar sodium dodecyl sulfate and polyoxyethylene(23) dodecanol, on the other hand, did not significantly affect the rate constants for nucleophilic aliphatic substitution reactions between neutral reactants (equations 39 and 40) in spite of the fact that anisylthioethane (see equation 40) is appreciably solubilized by the micelles while iodine cyanide is excluded (Herries et al., 1964). 

Lang found that, in the presence of cyanide, iodine is oxidized quantitatively to iodine cyanide. The standard potential of the half-reaction... 

Potassium periodate has been used in place of iodate for various titrations involving the iodine-chloride, iodine-bromide, and iodine-cyanide end points. Reaction of periodate with iodide involves transfer of an oxygen atom rather than an electron, followed by rearrangement of the structure of the IO4" ion. In the oxidation of the active oxidant appears to be 104 . An intermediate... 

The reaction of two uncharged species, anisylthioethane and iodine cyanide... 

Diazonium salts are quite useful in organic synthesis as the diazonium group can be easily replaced by fluorine, chlorine, bromine, iodine, cyanide, hydroxy, and hydrogen. In these diazonium replacement reactions, nitrogen gas is evolved. 

Alkyl iodyl derivatives, RIO2, usually lack stability and cannot be isolated. For example, the matrix isolation and FTIR spectra was reported of the unstable iodylalkanes, generated by the co-deposition and photolysis of ozone with iodoethane, 2-iodopropane, pentafluoroiodoethane, 1,1,1-trifluoroiodoethane, 1,1,2,2-tetrafluoroiodoethane, 1,1,1,2-tetrafluoroiodoethane, or iodine cyanide in an argon matrix at 14-16 K [668-670]. A relatively stable iodyltrifluoromethane, CF3IO2, was prepared by the reaction of CF3IF4 with silicon dioxide [671]. 

Acidification of the solution of pH 2.5 with H2SO4 causes the reaction between iodine cyanide and iodide as shown in reaction [VIII] ... 

One of the seven iodide ions formed reacts, at acid pH, with the iodine cyanide as shown in reaction [XV] ... 

When carried out according to Procedure I, this test is specific for cyanide with the sole exception of azide which behaves in the same manner as cyanide. If azide is present, it may be eliminated by prior treatment of the test portion of the sample with iodine and thiosulfate as described in Procedure II. See page 442 for details of this catalyzed iodine-azide reaction. 

Another methodology consists of operating in the presence of cyanide ions. Iodine is quantitatively oxidized into iodine cyanide (which may also be called cyanogen iodide). The half-redox reaction is... 

Nucleophilic aromatic substitutions involving loss of hydrogen are known. The reaction usually occurs with oxidation of the intermediate either intramoleculady or by an added oxidizing agent such as air or iodine. A noteworthy example is the formation of 6-methoxy-2-nitrobenzonitrile from reaction of 1,3-dinitrobenzene with a methanol solution of potassium cyanide. In this reaction it appears that the nitro compound itself functions as the oxidizing agent (10). 

Assay of hydrogen cyanide can be done by specific gravity or silver nitrate titration. Sulfur dioxide in hydrogen cyanide can be deterrnined by infrared analysis or by reaction of excess standard iodine solution and titration, using standard sodium thiosulfate or by measurement of total acidity by... 

Another process using butadiene as the starting material was developed by Esso. This involved the reaction of butadiene with iodine and cuprous cyanide to give the cuprous iodide complex of dehydroadiponitrile. This is further reacted with HCN to give a high yield of dehydroadiponitrile and regeneration of the iodine and cuprous iodide. 

The nitration of l,2,5-selenadiazolo[3,4-/] quinoline 77 with benzoyl nitrate affords the 8-nitro derivative 78, whereas methylation with methyl iodide or methyl sulfate afforded the corresponding 6-pyridinium methiodide 79 or methosulfate 80, respectively (Scheme 29). The pyridinium salt 80 was submitted to oxidation with potassium hexacyanoferrate and provided 7-oxo-6,7-dihydro derivative 81 or, by reaction of pyridinium salt 79 with phenylmagnesium bromide, the 7-phenyl-6,7-dihydro derivative 82. Nucleophilic substitution of the methiodide 79 with potassium cyanide resulted in the formation of 9-cyano-6,9-dihydroderivative 83, which can be oxidized by iodine to 9-cyano-l,2,5-selenadiazolo [3,4-/]quinoline methiodide 84. All the reactions proceeded in moderate yields (81IJC648). 

The reaction is a sensitive one, but is subject to a number of interferences. The solution must be free from large amounts of lead, thallium (I), copper, tin, arsenic, antimony, gold, silver, platinum, and palladium, and from elements in sufficient quantity to colour the solution, e.g. nickel. Metals giving insoluble iodides must be absent, or present in amounts not yielding a precipitate. Substances which liberate iodine from potassium iodide interfere, for example iron(III) the latter should be reduced with sulphurous acid and the excess of gas boiled off, or by a 30 per cent solution of hypophosphorous acid. Chloride ion reduces the intensity of the bismuth colour. Separation of bismuth from copper can be effected by extraction of the bismuth as dithizonate by treatment in ammoniacal potassium cyanide solution with a 0.1 per cent solution of dithizone in chloroform if lead is present, shaking of the chloroform solution of lead and bismuth dithizonates with a buffer solution of pH 3.4 results in the lead alone passing into the aqueous phase. The bismuth complex is soluble in a pentan-l-ol-ethyl acetate mixture, and this fact can be utilised for the determination in the presence of coloured ions, such as nickel, cobalt, chromium, and uranium. 

Fig. 7.2.9 Influence of cyanide and iodine on the Odontosyllis luciferin-luciferase luminescence reaction. Luciferin solution (0.1 ml) was first mixed with a HCN solution (0.1ml), and then the mixture was injected into 8 ml of 20 mM magnesium acetate containing luciferase. The concentrations of HCN shown in the figure are the final concentrations. In the control experiment, HCN was omitted. In the experiment labeled added at 0.5 min, 0.1 ml of HCN solution was injected to the control mixture 0.5 min after the start of the luminescence reaction to give a final concentration of 0.1 mM HCN. Arrows indicate the injection of a solution of I2-3KI to the control mixture to give a final concentration of 0.1 mM I2. From Shimomura et al., 1963d, with permission from John Wiley Sons Ltd.

Cyanide and thiocyanate anions in aqueous solution can be determined as cyanogen bromide after reaction with bromine [686]. The thiocyanate anion can be quantitatively determined in the presence of cyanide by adding an excess of formaldehyde solution to the sample, which converts the cyanide ion to the unreactive cyanohydrin. The detection limits for the cyanide and thiocyanate anions were less than 0.01 ppm with an electron-capture detector. Iodine in acid solution reacts with acetone to form monoiodoacetone, which can be detected at high sensitivity with an electron-capture detector [687]. The reaction is specific for iodine, iodide being determined after oxidation with iodate. The nitrate anion can be determined in aqueous solution after conversion to nitrobenzene by reaction with benzene in the presence of sulfuric acid [688,689]. The detection limit for the nitrate anion was less than 0.1 ppm. The nitrite anion can be determined after oxidation to nitrate with potassium permanganate. Nitrite can be determined directly by alkylation with an alkaline solution of pentafluorobenzyl bromide [690]. The yield of derivative was about 80t.with a detection limit of 0.46 ng in 0.1 ml of aqueous sample. Pentafluorobenzyl p-toluenesulfonate has been used to derivatize carboxylate and phenolate anions and to simultaneously derivatize bromide, iodide, cyanide, thiocyanate, nitrite, nitrate and sulfide in a two-phase system using tetrapentylammonium cWoride as a phase transfer catalyst [691]. Detection limits wer Hi the ppm range. 

As esters the alkyl halides are hydrolysed by alkalis to alcohols and salts of halogen acids. They are converted by nascent hydrogen into hydrocarbons, by ammonia into amines, by alkoxides into ethers, by alkali hydrogen sulphides into mercaptans, by potassium cyanide into nitriles, and by sodium acetate into acetic esters. (Formulate these reactions.) The alkyl halides are practically insoluble in water but are, on the other hand, miscible with organic solvents. As a consequence of the great affinity of iodine for silver, the alkyl iodides are almost instantaneously decomposed by aqueous-alcoholic silver nitrate solution, and so yield silver iodide and alcohol. The important method of Ziesel for the quantitative determination of alkyl groups combined in the form of ethers, depends on this property (cf. p. 80). 

In addition to anion adsorption, there exists the possibility of adsorption of cations at negative potentials along with coadsorption phenomena. For example, mixed layers of alkali cations with iodine on Au(llO) [291] or cyanide on Pt(lll) [292] have been reported. In fact, coadsorption has proven to be quite common among numerous underpotential metal deposition reactions as described below. 

The Ag2 S ISE has Nemstian response dE/d log a( = 0.0296 V in the sulphide concentration range 10" to 10" M and silver ions from 10 to 10 M if the solutions are prepared from pure salts, as a further concentration decrease is prevented by adsorption on the glass (see p. 76 and [87, 163]). After prolonged use, the limit of the Nemstian behaviour shifts to about 10" m [130] as a result of formation of mixed potentials on accumulation of metallic silver in the membrane surface. An analogous deterioration in the membrane function in the presence of iodine results from surface oxidation [23]. Cyanide interferes only at large concentrations the equilibrium constant of the reaction... 

Cyanogen iodide is prepared by the reaction of iodine on sodium cyanide NaCN -I-12 —> CNI -I- Nal... 

Methylbenzene halogen complex of, 3 122 iodine monochloridecomplese, 3 109 Methylchlorosilanes hydrolysis, 42 149-150, 157 pyrolysis products of, 7 356-363 Methylcobalamin, 19 151, 152 Methyl-coenzyme M reductase, 32 323-325 EPR spectra, 32 323, 325 F43 and, 32 323-324 function, 32 324-325 Methyl-CoM reductase, 32 329 Methyl cyanide, osmium carbonyl complexes, reaction, 30 198-201 Methylcyclophosphazene salts, 21 70 synthesis, 21 109... 

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