Iodine complex applications

Iodine makes blue colored complexes with many substances such as starch [1, 2] nylon-6 [3], poly(vinyl pyrrolidone) [4], poly(vinyl alcohol) PVA [5, 6], From the application point of view, the blue PVA-Iodine complex is the most important among them, for it is widely used for film polarizers [7,8]. The polarizers are prepared by soaking PVA films in a solution of iodine and potassium iodide (KI) with boric acid, and subsequent drawing to cause the high... 

A method of determining airborne iodine has also been reported.241 Here, iodine is absorbed into 5% aqueous KI and spectrophotometrically determined at 590 nm in the form of its complex with starch. This method is selective with respect to bromine and chlorine, and the sensitivity of this method is 0.25 mg of I2 per m3 of air. The concentration of the, 31I isotope in water can be determined by a method involving isotope exchange in the starch-iodine complex.242 Flow-injection determination of ascorbic acid (0.1-40 mg/mL) has been proposed.243 Iodine is generated in the flow system as I3- ions, which are in turn exposed to starch to produce a steady signal at 350 and 580 nm. Ascorbic acid provides inversed maxima which are measured. This method is recommended for analysis of ascorbic acid in fruit juice, jam, and vitamin-C preparations. Use of the blue complex has also been reported for determination of sodium dichloro-isocyanurate in air.244 Obviously the blue reaction is applicable in the determination of amylose, amylopectin, and starch,245-252 as well as modified starches.245,253-255... 

Use of the starch-iodine complex has been reported for the disinfection of wounds and for the artificial insemination of animals.310 Food containers may also be disinfected with this complex.311 Uses of the starch-iodine complex in the iodization of food312,313 and ruminant fodder314 have also been described. This complex has been found effective in the storage preservation of cabbage and carrots,315 potatoes,316 and apples 317 The addition of 0.0005 to 0.005% of the complex to bee honey also improves its properties it was reported that the application of a 1% aqueous solution of the complex for spraying bee houses increased the yield of honey.318... 

The application of these techrriques is corrsiderably erthanced by the irttroduction of sarrrple-seeded supersonic jets. Gas-phase spectra are obtained at terrtperatures close to the absolrrte zero arrd the problem of Boltzmaim congestion is effectively overcome. Besides making the artalysis of previously hopelessly congested spectra tractable it has revealed a new farrrily of weakly-botmd van der Waals dimers or clusters. Some of the analyses are limited to general conclusions, as e.g. the distinction between end-on and sideways-on orientation of diatomic iodine in a benzene-iodine complex. Such data are not included in the present compilation. Other analyses, however, yield acciuate intemuclear distances as in the benzene-rate gas complexes. 

The methods evaluated for KHI analyses are colorimetric, iodine complexation, and size exclusion chromatography (SEC). The colorimetric method is subject to intense interference by Cl, limiting its application for KHI determination in the presence of Cl blends. The iodine complexation method is chosen as a practical wet chemical method for KHI analysis.lt is modified to minimize the interferences due to brine concentration, corrosion inhibitor, condensate, and sulfide. However, the selectivity of the iodine complexation method is still not at the desired level. As an improvement to selectivity and accuracy, the SEC method is evaluated. The SEC method offers better selectivity and characterization of KHI. The characterization of molecular weight distribution is critical in the evaluation of treatment and removal efficiency of KHI in produced water streams. 

A UK standard official method [62] has been published for the spectropho-tometric determination of arsenic in sea water. The determination is effected by conversion to arsine using sodium borohydride which is added slowly to the acidified samples by a peristaltic pump. The liberated arsine is trapped in an iodine/potassium iodide solution and the resultant arsenate determined spectrophotometically as the arsenomolybdenum blue complex at 866 nm. The method is applicable down to 0.19 p,g arsenic. 

Applying the pseudo-atom convention to the iron complex in Figure 8, the iodine atom is priority 1, the t1S-C5H3R2 ligand is priority number 2, the phosphorus atom is priority number 3, and carbon is priority number 4.15 When the iron is viewed from the side opposite the priority number 4, the sequence is 1,2,3 in the anticlockwise or 5 direction. The highest priority carbon in the cyclopentadienyl ligand, indicated by an asterisk, is designated with the R chirality symbol by application of the extended CIP sequence rule. 

Minor industrial uses include the application of silver iodide as a smoke for the seeding of clouds to induce rainfall. Compounds used for obtaining some nonflammable plastics and cellulose are benzyltriphenyl-phosphoniumiodides and [2,-(acetyloxy)ethyl] triphenyl-phosphoniumiodides (see Flame RETARDANTS, HALOGENATED FLAME retardants) (142). The addition of iodine to an aromatic hydrocarbon such as -butylbenzene results in the formation of charge-transfer complexes that display outstanding effectiveness as lubricants for hard-to-lubricate metals (143), such as titanium or steels (see also LUBRICATION AND LUBRICANTS). Iodine is also used in the production of high purity metals such as titanium, silicon, hafnium, and zirconium (144). 

Povidone-iodine is a macromolecular complex (poly-I(I-vinyl-2-pyrrolidinone) that is used as an iodophor. It is formulated as a 10% applicator solution, a 2% cleansing solution, and in many topical formulations, for example aerosol sprays, aerosol foams, vaginal gels, ointments, and mouthwashes. Because it contains very little free iodine (less than 1 ppm in a 10% solution) its antibacterial effectiveness is only moderate compared with that of a pure solution of iodine. 

Complexation equilibria are treated in the same manner as acid-base equilibria. The slightly different look of applicable equations is simply the result of the direction of the equilibria in acid-base and complex formation reactions. The former is conventionally written as proton dissociation, and the latter as metal-ligand association, as exemplified by the reaction of Run(NH3)5isn2 + (isn = isonicotinamide) with iodine in acidic aqueous solutions, Equation 8.108. 

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