Iodine with alcohols

I he methyl iodide is transferred quantitatively (by means of a stream of a carrier gas such as carbon dioxide) to an absorption vessel where it either reacts with alcoholic silver nitrate solution and is finally estimated gravimetrically as Agl, or it is absorbed in an acetic acid solution containing bromine. In the latter case, iodine monobromide is first formed, further oxidation yielding iodic acid, which on subsequent treatment with acid KI solution liberates iodine which is finally estimated with thiosulphate (c/. p. 501). The advantage of this latter method is that six times the original quantity of iodine is finally liberated. 

Iodine compounds are important in organic chemistry and very useful in medicine. Iodides, and thyroxine which contains iodine, are used internally in medicine, and as a solution of KI and iodine in alcohol is used for external wounds. Potassium iodide finds use in photography. The deep blue color with starch solution is characteristic of the free element. 

Chlorine and bromine add vigorously, giving, with proper control, high yields of 1,2-dihaloethyl ethers (224). In the presence of an alcohol, halogens add as hypohaUtes, which give 2-haloacetals (225,226). With methanol and iodine this is used as a method of quantitative analysis, titrating unconsumed iodine with standard thiosulfate solution (227). 

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. 

Magnesium iodide is soluble in alcohols and many other organic solvents, and forms numerous addition compounds with alcohols, ethers, aldehydes, esters, and amines. One example is magnesium iodide dietherate [29964-67-8], Mgl2 prepared by gradual addition of iodine to a... 

Worenine. This alkaloid, also obtained by Kitasato from Coptis japonica was isolated as the tetrahydro-base, C,oHjg04N, which crystallises from alcohol in colourless prisms, m.p. 212-3°, and is oxidised by iodine in alcohol to worenine iodide, yellow crystals from which worenine chloride, thin orange-yellow prisms, m.p. 295° (dec.), can be obtained. Tetrahydro-worenine behaves as a tertiary base, contains methylenedioxy- but no methoxyl groups, and its absorption spectrum closely resembles that of tetrahydrocoptisine from which it differs in empirical composition by. CHj. Worenine is, therefore, represented by (XXX), the alternative position (a) for the methyl group being untenable, since a-methyltetra-hydrocoptisine obtained by Freund s method is not identical with... 

Cucumber cotyledons were inoculated with purified tobacco mosaic virus (TMV) 20 to 24 hours before vacuum infiltration with different concentrations of crude water extracts of plant leaves (4). After 7 days, inoculated leaves were harvested and stored 24 hours in the dark in a moist chamber to remove excess starch. Starch lesions were counted after clearing with alcohol and staining with an iodine-potassium iodide-lactic acid mixture. The inhibitory effects of various extracts were demonstrated by comparing lesion counts of treated cotyledons to counts on control cotyledons. 

There is a risk of acute renal failure when iodi-nated contrast material that is used for radiological studies is administered with metformin. Metformin therapy is stopped for 48 hours before and after radiological studies using iodinated material. Alcohol, amiloride, digoxin, morphine, procainamide, quini-dine, quinine ranitidine, triamterene, trimethoprim, vancomycin, cimetidine, and furosemide all increase the risk of hypoglycemia. There is an increased risk of lactic acidosis when metformin is administered with the glucocorticoids. 

Commercial absolute alcohol was further dried by treatment with magnesium and a little iodine with subsequent redistillation, as described by Lund and Bjerrum.6... 

Gram Stain A staining procedure used in classifying bacteria. A bacterial smear on a slide is stained with a purple basic triphenyl methane dye, usually crystal violet, in the presence of iodine/potassium iodide. The cells are then rinsed with alcohol or other solvent, and then counter-stained, usually with safranin. The bacteria then appear purple or red according to their ability to keep the purple stain when rinsed with alcohol. This property is related to the composition of the bacterial cell wall. 

The procedure given here is essentially that described previously by the submitters. -Chlorophenyl isothiocyanate has been prepared from sym-di-p-chloiophenyl thiourea with iodine in alcoholic solution, from ammonium p-chlorophenyldithio-carbamate and lead nitrate [cf. also Org. Syntheses, Coll. Vol. 1 447 (1932)], by the action of thiophosgene on />-chloroaniline and from -chloroaniline with thiocarbonyl tetrachloride in the presence of stannous chloride. ... 

Although Schardinger did not propose a structure for his crystalline dextrins, he made several observations that can now be attributed to their cyclic structure. For example, he discovered their ability to engage in complex-formation "With various substances, the crystalline dextrins form loose complexes which, like those produced with alcohol, ether, and chloroform, are indeed partly decomposed by water, while the iodine complexes are more stable toward water. He also found, as previously mentioned, that the crystalline dextrins were nonreducing toward copper salts and nonfermentable by yeast. This last observation he considered was "... the most essential thing that I was able to mention concerning the formation of crystalline dextrins by microbes. Both of these observations can be explained by the lack of a chain termination. 

Iodine is the least reactive of the elements in the halogen group 17. Most people associate iodine with the dark-brown color of the tincture of iodine used as an antiseptic for minor skin abrasions and cuts. A tincture is a 50% solution of iodine in alcohol. Although it is still used, iodine is no longer the antibiotic of choice for small skin wounds. Since iodine is a poison that kills bacteria, iodine tablets are often used by campers and others to purify water that is taken from outdoor streams. 

Hydriodic acid is a colorless liquid when pure or freshly prepared becomes yellowish or brown on exposure to light or air strong acid odor pH of 0.1 molar solution, 1.0 a 0.1 M aqueous solution is 95% ionized at 25°C miscible with alcohols dissolves iodine. 

Although in part this order may be affected by subsequent reaction of the iodine with the organic solvent under the influence of catalytic material in the charcoal (Schmidt, Z it KoUoid. Ghem. XIV. 242, 1914) yet similar alterations have been noted by Freundlich (ibid. p. 260) with other solutes, e.g. benzoic and picric acids, who found the following order for decreasing adsorption for benzoic acid water, benzene, ethyl ether, acetone for picric acid, water, ethyl, alcohol, benzene. 

Phosphorus halides react with alcohols to yield alkyl halides at low temperature (0 °C). Primary and secondary alcohols undergo Sn2 reactions with PX3. This type of reaction does not lead to rearranged products, and does not work well with 3° alcohols. PI3 has to be generated in situ via reaction of iodine and phosphorus. 

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