Iodic acid, iodination with

According to H. Kammerer,25 chloric acid reacts with bromine, giving only traces of bromic acid but with iodine it forms iodic acid, and with iodine chlorides it furnishes iodic acid and chlorine bromic acid is not affected by chlorine, but with iodine it forms iodic acid. When a soln. of potassium chlorate acidified with... 

A. J. Balard showed that bromic acid is decomposed by hydrobtomic add into bromine and water by hydrochloric acid into water an d bromine chloride and by hydriodic acid into water and iodine bromide. There are nine reactions belonging to this set, namely, chloric, bromic, and iodic acids each with each of the three haloid acids—HC1, HBr, and HI. The kinetics of these reactions have been studied extensively.29 W. Bray has shown that the velocity of the reaction between... 

TELLURIUM (13494-80-9) Finely divided powder or dust may be flammable and explosive. Violent reaction with strong oxidizers, bromine pentafluoride, halogens, interhalogens, iodine pentafluoride, hexalithium disilicide, lithium silicide, nitrosyl fluoride, oxygen difluoride, sodium peroxide, sulfur, zinc. Incompatible with cadmium, cesium, hafnium, strong bases, chemically active metals, iodic acid, iodine oxide, lead chlorite, lead oxide, mercury oxides, nitric acid, peroxyformic acid, platinum, silver bromate/iodate/ fluoride, nitryl fluoride, sodium nitrate. 

Iodic acid may be made by oxidising iodine with excess fuming nitric acid according to the equation... 

About 0.5 g of iodine is placed in a small flask fitted with a long reflux air condenser and 15 cm of fuming nitric acid (b.p. 380 K) are added. The mixture is then heated on a water bath at 385-390 K in a fume cupboard until the reaction seems to be complete. This takes about an hour. The solution is then transferred to an evaporating basin and evaporated to dryness on a steam bath. The iodic acid... 

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. 

Hydroiodic acid reacts quantitatively with iodic acid to give iodine ... 

C. HIO is prepared by oxidation of iodine with perchloric acid, nitric acid, or hydrogen peroxide or oxidation of iodine in aqueous suspension to iodic acid by silver nitrate. Iodic acid is also formed by anodic oxidation at a platinum electrode of iodine dissolved in hydrochloric acid (113,114). 

Iodine monochloride [7790-99-0] ICl, mol wt 162.38, 78.16% I, is a black crystalline soHd or a reddish brown Hquid. SoHd ICl exists ia two crystalline modifications the a-form, as stable mby-red needles, d = 3.86 g/mL and mp 27.3°C and as metastable brownish red platelets, d = 3.66 g/mL, mp 13.9°C and bp 100°C (dec). Iodine monochloride is used as a halogenation catalyst and as an analytical reagent (Wij s solution) to determine iodine values of fats and oils (see Fats and fatty oils). ICl is prepared by direct reaction of iodine and Hquid chlorine. Aqueous solutions ate obtained by treating a suspension of iodine ia moderately strong hydrochloric acid with chlorine gas or iodic acid (118,119). 

Most nonmetallic elements (except nitrogen, oxygen, chlorine, and bromine) are oxidized to their highest state as acids. Heated with concentrated acid, sometimes ia the presence of a catalyst, sulfur, phosphoms, arsenic, and iodine form sulfuric, orthophosphoric, orthoarsenic, and iodic acid, respectively. SiHcon and carbon react to produce their dioxides. 

The dependence of reaction rates on pH and on the relative and absolute concentrations of reacting species, coupled with the possibility of autocatalysis and induction periods, has led to the discovery of some spectacular kinetic effects such as H. Landolt s chemical clock (1885) an acidified solution of Na2S03 is reacted with an excess of iodic acid solution in the presence of starch indicator — the induction period before the appearance of the deep-blue starch-iodine colour can be increased systematically from seconds to minutes by appropriate dilution of the solutions before mixing. With an excess of sulfite, free iodine may appear and then disappear as a single pulse due to the following sequence of reactions ... 

Hesse and Mix (29) oxidized a relatively concentrated solution of triose reductone using limited amounts of free periodic acid. In these conditions, the iodic acid formed by the initial reduction of periodic acid could be further reduced and the reduction product could then, in turn, react with the remaining periodic acid and liberate iodine. Thus glyoxylic acid could be isolated from the oxidation mixture, as no periodate was available for its oxidation. 

Introduction of iodine by Sandmeyer processes has been discussed [84AHC(35)83], Direct electrophilic iodination is also observed in the 3-position with reagents such as iodine monochloride, iodine-iodic acid-acetic acid, or molecular iodine. With excess reagent, or when C-3 is blocked, 6-iodination follows [84AHC(35)83 84MI15]. 

Fluorescein (147) is prepared by the same route as Pigment Red 90 (see p. 575). The compound is iodized with iodine and potassium iodate in an acidic medium. The iodic acid reoxidizes the resulting hydrogen iodide back to iodine ... 

The substance is burned on a platinum catalyst in a stream of oxygen and the iodine liberated is oxidised to iodic acid by bromine in acetic acid. After excess bromine has been removed with formic acid, potassium iodide is added to the solution, and the iodine liberated is titrated with thiosulphate. Since the amount of iodine titrated is six times the iodine content of the substance the method yields very accurate results. 

Iodic(V) acid is prepared by oxidising iodine with concentrated nitric acid ... 

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