Iodination using

Titration Indicators. Concentrations of arsenic(III) as low as 2 x 10 M can be measured (272) by titration with iodine, using the chemiluminescent iodine oxidation of luminol to indicate the end point. Oxidation reactions have been titrated using siloxene the appearance of chemiluminescence indicates excess oxidant. Examples include titration of thallium (277) and lead (278) with dichromate and analysis of iron(II) by titration with cerium(IV) (279). 

A large reserve of caUche ore bearing iodine is being processed in the Atacama Desert. Production of iodine there is relatively inexpensive. About 40% of the world supply of iodine is made from these Chilean deposits. The process consists of leaching the caUche with water. Brine is stripped of iodine using an organic solvent. The iodine is then removed from the solvent to form a slurry. SoHd-phase iodine is separated from the slurry in conventional flotation cells, dried, and packaged. Details of the process are proprietary. 

Economic Aspects and Uses. Most of the iodine used in the United States comes from Japan and Chile. The United States produces 10% of the world supply but consumes 30%. Production in Chile appears to be relatively low cost, and the product there presently controls prices. Iodine is produced in Woodward and Vici, Oklahoma. These two locations produce about 30% of the 4000 tons used yearly in the United States. Total world consumption is 10,000 to 12,000 tons per year. Prices range from 20.00/kg in 1988 to 12.5/kg in 1991. 

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. 

The rate is obtained by following the disappearance of iodine using starch as an indicator. The following data are obtained ... 

Ethyl acrylate is used in approximately 50% molar excess over the expensive, limiting reagent, iodine. Use of an equimolar amount results in a lower yield (85%). The checkers distilled the reagent at 20° (39 mm.) prior to use. 

Aspirate through ammoniacal cadmium chloride strip sulfur dioxide by aeration dissolve cadmium sulfide precipitate in concentrated HC1 titrate with iodine using a starch indicator. Iodometric titration 0.7 qg/L NR EPA 1978... 

A set of Pacific open-ocean samples were analysed for iodate-iodine using both the procedure which incorporates pre-oxidation with iodine water and that which does not. Also, in a similar exercise total iodine was determined using both the method that incorporates pre-oxidation with bromine water and the catalytic method using the reaction between Ce(IV) and As(III) [81]. Variance tests showed that differences between either replicates or methods was not significant. 

The critical datum is not a buret reading, as it was in the case of the volumetric method. Rather, the amount of iodine used is determined coulometrically by computing the coulombs (total current over time) needed to reach the end point. The coulombs are calculated by multiplying the current applied to the anode-cathode assembly (a constant value) by the total time (seconds) required to reach the end point. The modern coulometric titrator automatically computes the amount of moisture from these data and displays it. 

Karl Fischer reagent analy chem A solution of 8 moles pyridine to 2 moles sulfur dioxide, with the addition of about 15 moles methanol and then 1 mole iodine used to determine trace quantities of water by titration. karl fish-or re a-jont Karl Fischer technique analy chem A method of determining trace quantities of water by titration the Karl Fischer reagent is added in small increments to a glass flask containing the sample until the color changes from yellow to brown or a change in potential is observed at the end point. karl fish-or tek nek kauri-butanol value analychem The measure of milliliters of paint or varnish petroleum thinner needed to cause cloudiness in a solution of kauri gum in butyl alcohol. kail-re byut-3n,ol, val-yu ... 

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. 

The isotope iodine-131 is an artificial radioisotope of iodine used as a tracer in biomedical research and as a treatment for thyroid disease. 1-131 has a half-hfe of about eight days, which means it will be eliminated from the body in several weeks. 

Compound 12 displays an altogether different reactivity pattern upon treatment with iodine in the presence of an ether or a thioether. Thus, the sole product of the reaction of 12 in THF with iodine was the anionic Mo complex [N(PPh3)2][2,2,2-(CO)3-2-I-7-0(CH2)4-c/oxo-2,1-MoCBioHio] (67), with the carborane cage having undergone a substitution at a boron vertex. The substitution occurs at a p boron atom in the CBBBB face that ligates the molybdenum atom. When 67 is treated with further iodine in THF no reaction occurs. However, treatment with iodine using... 

Iodized salt prophylaxis. Goiter is endemic in regions where soils are deficient in iodine. Use of iodized table salt allows iodine requirements (150-300 pg/d) to be met and effectively prevents goiter. 

Binding Energy Curve for Iodine Using Laser Spectroscopy 47... 

Less emission against the environmental pollution. The 2, dyes, and iodine used in the DSSCs are nontoxic. The only component that could potentially cause harm is the organic solvents used as the electrolyte solution. Future research should be directed toward developing a solid-state electrolyte. 

Quantitative Determination. Dissolve 1 gin. of potassium stniniosulplinte in u solution of R gni. of sodium hienr-houule innl r, gm. of potassium and sodium tartrate in 1(M) c.o. of wain-, and titrate the dear li( nid with deeinorinal iodine, using standi solution as tlio indicator. 

Yield about 75% of theory based on the iodine used... 

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