Iodine replacement

Halogen (X = fluorine, chlorine, bromine or iodine) replaces -H on hydrocarbon group... 

Carnallite, KCl-MgCh-6H20.—A similar salt is to be expected with ammonium, rubidium, or cesium replacing potassium, zinc, cadmium, iron, nickel, cobalt, or stannous tin, replacing magnesium and bromine and occasionally iodine replacing chlorine. Many of these are known but not all. (Mellor, II, 430.)... 

Yields for chlorine, bromine and iodine replacement and the reaction time required under optimal experimental conditions are given in Table 3. 

The anionic lO-Bi-4 species, (2), has distorted pseudotrigonal bipyramidal geometry about the bismuth atom <92TL6653>. The corresponding iodinium triflate, where tetracoordinate, cationic iodine replaces the bismuth atom, assumes similar geometry <82JA902, 93JA2488>. 

Examples of allylation [39a] and vinylation [39b] are shown in Scheme 24. The dichlorovinylation is especially interesting since the products are immediate precursors of alkynes via the Corey-Fuchs reaction. The process is also applicable to aliphatic iodides, exchange of iodine replacing the exchange of xanthate in the mechanistic manifold in Scheme 22 [39b,c[. 

Fluorine ions, which are similar in diameter to oxygen ions, are believed to substitute directly for NBO on the silicon-oxygen tetrahedra, providing breaks in the vitreous network. In contrast, it has been suggested that chlorine, bromine, and iodine replace BO at low halide concentrations and only replace NBO when the concentration of PbX2 exceeds 5 to 10 mol%. 

The monosubstitution product (iodine replaced) was isolated in 22% yield. 

Alkyl halides are compounds in which a halogen atom (fluorine, chlorine, bromine, or iodine) replaces a hydrogen atom of an alkane. For example, CH3CI and CH3CH2Br are alkyl halides. Alkyl halides are also called haloalkanes. The generic formula for an alkyl halide is R—X where X = fluorine, chlorine, bromine, or iodine. 

The common names of alkyl halides consist of the name of the alkyl group, followed by the name of the halogen—with the ine ending of the halogen name (fluorine, chlorine, bromine, and iodine) replaced by ide (fluoride, chloride, bromide, and iodide). 

The diazonium salts usually decompose when warmed with water to give a phenol and nitrogen. When treated with CuCl, CuBr, KI, the diazo group is replaced by chlorine, bromine or iodine respectively (Sandmeyer reaction). A diazonium sulphate and hydroxyl-amine give an azoimide. The diazonium salt of anthranilic acid (2-aminobenzoic acid) decomposes to give benzyne. ... 

Iodine does not replace hydrogen from saturated hydrocarbons directly, as do both chlorine and iodine. 

It is believed that the red phosphorus is the true reducing agent and the iodine (or iodide) functions as a hydrogen carrier. This proc ure replaces the obsolete method of heating with red phosphorus and concentrated hydriodic acid in a sealed tube. 

This simplified method gives 2-aminothiazole in good yield (50 to 70%) (311, 330), Other reactants can replace iodine, for example, chlorine, bromine, sulfuryl chloride, chlorosulfonic acid, or sulfur monochloride also give good results. 

Hypohahtes replace the acetylenic hydrogen with chlorine, bromine, or iodine (203). 

Mesylated and Tosylated Celluloses. It has been estabUshed that the flame resistance of ceUulose (qv) is improved by oxidation of —CH2OH groups to —COOH (58—60). To correct some of the shortcomings of this treatment, mesyl or tosyl ceUulose was prepared and then the mesyl (CH2SO2) or tosyl (CH2CgH4S02) group was replaced with bromine or iodine (58—60) ... 

The aHphatic iodine derivatives are usually prepared by reaction of an alcohol with hydroiodic acid or phosphoms trHodide by reaction of iodine, an alcohol, and red phosphoms addition of iodine monochloride, monobromide, or iodine to an olefin replacement reaction by heating the chlorine or bromine compound with an alkaH iodide ia a suitable solvent and the reaction of triphenyl phosphite with methyl iodide and an alcohol. The aromatic iodine derivatives are prepared by reacting iodine and the aromatic system with oxidising agents such as nitric acid, filming sulfuric acid, or mercuric oxide. 

The iodine compound is more stable and separates as so-called nitrogen trHodide monoammoniate [14014-86-9], NI NH, an insoluble brownish-black soHd, which decomposes when exposed to light in the presence of ammonia. In reactions of the halogens with the respective ammonium salts, however, the action is different. Chlorine replaces hydrogen and nitrogen chloride [10025-85-1], NCl, separates as oily, yeUow droplets capable of spontaneous explosive decomposition. 

The hydrogen of the ammonium salt is not replaced by bromine and iodine. These elements combine with the salt to form perhaHdes. 

Any radioactive nucUde or isotope of an element can be used as a radioactive tracer, eg, chromium-51 [14392-02-0] cobalt-60 [10198-40-0] tin-110 [15700-33-1] and mercury-203 [13982-78-0],hut the preponderance ofuse has been for carbon-14 [14762-75-5],hydj ogen-3 [10028-17-8] (tritium), sulfur-35 [15117-53-0], phosphoms-32, and iodine-125 [14158-31 -7]. More recendy phosphoms-33 has become available and is used to replace sulfur-35 and phosphoms-32 in many appUcations. By far the greater number of radioactive tracers produced are based on carbon-14 and hydrogen-3 because carbon and hydrogen exist in a large majority of the known natural and synthetic chemical compounds. 

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