From hydrogen iodide

Methanol can scarcely be chiefly formed from methoxy radicals since these would abstract from hydrogen iodide to give methane and water in the same way as methyl and hydroxyl radicals. Therefore, methanol must be produced from methyl peroxy radicals by the reaction... 

Iodocyclohexane has been prepared by the action of phosphorus and iodine on cyclohexanol,2 and from hydrogen iodide and cyclo-hexanol,3 chlorocyclohexane,4 or cyclohexyl ether.5 It has also been prepared by reaction of potassium iodide and chlorocyclohexane.6... 

The structural formulae of these compounds, whether written with the usual bonds or with valency electrons, are clearly quite analogous to those of the alkyl derivatives of ammonia (see this Volume, Part I.). Thus the presence of-even one methyl group enables the phosphorus to accept a hydrogen ion from hydrogen iodide, giving a crystalline product which is not dissociated under ordinary conditions —... 

Clearly under these conditions the concentrations of HCl and 12 will be enormously large compared with those of HI and Cl 2 so that we can conclude that chlorine will displace iodine from hydrogen iodide. 

Hydriodic acid, which is used to make pharmaceuticals, is made from hydrogen iodide. The hydrogen iodide is made from hydrogen gas and iodine gas in the following exothermic reaction. 

All A-halo compounds can be readily determined by analysis based on their oxidizing action. They liberate two equivalents of iodine from acidified potassium iodide solution almost instantaneously (1 mmole of A-monohalo compound is equivalent to 20 ml of O.In-thiosulfate solution). The liberation of iodine from hydrogen iodide involves production of the amine or amide parent of the halo compound. Sodium sulfite and hydrogen sulfide also reduce N-halo compounds. UV and IR spectroscopic methods have been worked out for determination of JV-halo compounds.399... 

Pleurotin. This compound (142a) has the empirical formula, C20H22O5, m.p. 209°C. (dec.), yellow or amber needles, [o ]n = —20° in chloroform, absorption peak at 2500 A very soluble in chloroform soluble in alcohol, acetone, ether, and benzene nearly insoluble in water and petroleum ether gives no color with ferric chloride, releases iodine from hydrogen iodide. It reacts with potassium cyanide to give a blue color, which is the basis of a chemical method of assay (101a). One mole of pleurotin reacts... 

These values indicate a rapid fall in thermal stability of the halide from fluorine to iodine, and hydrogen iodide is an endothermic compound. If we now examine the various enthalpy changes involved. we find the following values (in kJ) ... 

For 2-amino-4- m-nitrophenyl) seienazole, the yield is particularly high. This has been explained by the oxidizing effect of the nitro group, which liberates iodine from the hydrogen iodide eliminated in the condensation reaction. 

Catalysts. Iodine and its compounds ate very active catalysts for many reactions (133). The principal use is in the production of synthetic mbber via Ziegler-Natta catalysts systems. Also, iodine and certain iodides, eg, titanium tetraiodide [7720-83-4], are employed for producing stereospecific polymers, such as polybutadiene mbber (134) about 75% of the iodine consumed in catalysts is assumed to be used for polybutadiene and polyisoprene polymeri2a tion (66) (see RUBBER CHEMICALS). Hydrogen iodide is used as a catalyst in the manufacture of acetic acid from methanol (66). A 99% yield as acetic acid has been reported. In the heat stabiH2ation of nylon suitable for tire cordage, iodine is used in a system involving copper acetate or borate, and potassium iodide (66) (see Tire cords). 

Various reducing agents, eg, hydrogen iodide, can abstract chlorine from sulfur monochloride leaving elemental sulfur ... 

Titanium tetraiodide can be prepared by direct combination of the elements at 150—200°C it can be made by reaction of gaseous hydrogen iodide with a solution of titanium tetrachloride in a suitable solvent and it can be purified by vacuum sublimation at 200°C. In the van Arkel method for the preparation of pure titanium metal, the sublimed tetraiodide is decomposed on a tungsten or titanium filament held at ca 1300°C (152). There are frequent hterature references to its use as a catalyst, eg, for the production of ethylene glycol from acetylene (153). 

Zirconium monochloride and zirconium monobromide [31483-18-8] are prepared in better purity by equiUbration of mixed lower haUdes with zirconium foil at 625°C (184—185) or by slowly heating zirconium tetrahaUde with zirconium turnings at 400—800°C over a period of two weeks and hoi ding at 800—850°C for a few additional days (186). Similar attempts to produce zirconium monoiodide [14728-76-8] were unsuccesshil it was, however, obtained from the reaction of hydrogen iodide with metallic zirconium above 2000 K (187). 

Hydrogen iodide (anhydrous) [10034-85-2] M 127.9, b -35.5°. After removal of free iodine from aqueous HI, the solution is frozen, then covered with P2O5 and allowed to melt under vacuum. The gas evolved is dried by passage through P2O5 on glass wool. It can be freed from iodine contamination by repeated fractional distillation at low temperatures. Fumes in moist air. HARMFUL VAPOURS. 

A considerable extension of the synthetic utility of the hypoiodite reaction is achieved if the steroid hypoiodite (2) is generated from the alcohol and acetyl hypoiodite and then decomposed in a nonpolar solvent. In this case ionic hydrogen iodide elimination in the 1,5-iodohydrin intermediate (3) is slow, thereby allowing (3) to be converted into an iodo hypoiodite (5). 

Hydrogen iodide is easily eliminated by strong bases from perfluoroalky lethy 1 iodides to give terminal alkenes With perfluoroalkylpropyl iodides, however, replacement of iodine by nucleophiles predominates over the elimination reacUon [f] (equation 1)... 

Crabtree, Johnson, and Tebby then showed that the methoxymethylindolizine, originally formulated as (109), on successive treatment with hydrogen iodide and diazomethane gave (110). The methoxymethylindolizine must, therefore, be (111) and a similar compound was obtained from 3-methylpyridine. Attempts to convert corresponding labile (77) and stable adducts (78) into (111) by... 

The most characteristic property of the oxaziranes is tlieir strong oxidizing character which is approximately equal to that of hydrogen peroxide. Oxaziranes react with hydrochloric acid the chlorine thus liberated is, however, used up in secondary reactions. " Two equivalents of iodine are formed from acid iodide solutions according to Eq. Titration of the free iodine allows a simple estimation of... 

A variation of the general method for the synthesis of 2-amino-selenazoles is to avoid the use of the free a-halogenocarbonyl compound and in its place react the corresponding ketone and iodine with selenourea.This procedure is also taken from thiazole chemistry. By contrast with thiourea, the reaction with selenourea needs a longer reaction time and the work up of the reaction mixture is somewhat more difficult. Usually an excess of the ketone is used. In the preparation of 2-amino-4-( n-nitrophenyl)selenazole, a very high yield, calculated on the amount of iodine used, was obtained. To explain this peculiar result, the oxidative action of the nitro group was invoked. This liberates free iodine from some of the hydrogen iodide eliminated in the condensation reaction, and the free iodine then re-enters into the reaction. 

In the chemical process industry molybdenum has found use as washers and bolts to patch glass-lined vessels used in sulphuric acid and acid environments where nascent hydrogen is produced. Molybdenum thermocouples and valves have also been used in sulphuric acid applications, and molybdenum alloys have been used as reactor linings in plant used for the production of n-butyl chloride by reactions involving hydrochloric and sulphuric acids at temperatures in excess of 170°C. Miscellaneous applications where molybdenum has been used include the liquid phase Zircex hydrochlorination process, the Van Arkel Iodide process for zirconium production and the Metal Hydrides process for the production of super-pure thorium from thorium iodide. 

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