Iodine, requirement

These two equations can be combined by recognizing that a conservation of mass for iodine requires that... 

Direct bromination readily yields the 6-bromo derivative (111), just as with uracil. Analogous chlorination and iodination requires the presence of alkalies and even then proceeds in low yield. The 6-chloro derivative (113) was also obtained by partial hydrolysis of the postulated 3,5,6-trichloro-l,2,4-triazine (e.g.. Section II,B,6). The 6-bromo derivative (5-bromo-6-azauracil) served as the starting substance for several other derivatives. It was converted to the amino derivative (114) by ammonium acetate which, by means of sodium nitrite in hydrochloric acid, yielded a mixture of 6-chloro and 6-hydroxy derivatives. A modified Schiemann reaction was not suitable for preparing the 6-fluoro derivative. The 6-hydroxy derivative (115) (an isomer of cyanuric acid and the most acidic substance of this group, pKa — 2.95) was more conveniently prepared by alkaline hydrolysis of the 6-amino derivative. Further the bromo derivative was reacted with ethanolamine to prepare the 6-(2-hydroxyethyl) derivative however, this could not be converted to the corresponding 2-chloroethyl derivative. Similarly, the dimethylamino, morpholino, and hydrazino derivatives were prepared from the 6-bromo com-pound. ... 

The alkaline solution of thymol is made up to 100 or 200 c.c. as the case may require, using a 5 per cent, soda solution. To 10 c.c. of this solution in a graduated 500 c.c. flask is added a normal iodine solution in shgbt excess, whereupon the thymol is precipitated as a dark reddish-brown iodine compound. In order to ascertain whether a sufficient quantity of iodine has been added, a few drops are transferred into a test tube and a few drops of dilute hydrochloric acid are added. When enou iodine is present, the brown colour of the solution indicates the presence of io ne, otherwise the liquid appears milky by the separation of thymol. If an excess of iodine is present, the solution is slightly acidified with dilute hydrochloric acid and diluted to 500 c.c. From this 100 c.c. are filtered,off, and the excess of iodine determined by titration with normal solution of sodium thiosulphate. For calculation, the number of cubic centimetres required is deducted from the number of cubic centimetres of normal iodine solution added and the resultant figure multiplied by 5, which gives the number of cubia centimetres of iodine required by the thymol. 

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. 

Iodide or iodate are used to iodize salt. The level of salt iodization depends on per capita salt consumption, moisture, light, heat, and contaminants. The recommended daily iodine requirements are 50 pg for infants, 90 pg for children (2-6 yrs), 120 pg for schoolchildren (7-12 yrs), 150 pg for adults and 200 pg for pregnant and lactating women. 

Delange F Iodine requirements during pregnancy, lactation and the neonatal period and indicators of optimal iodine nutrition. Public Health Nutr 2007 10 1571. [PMID 18053281]... 

Zimmermann MB Iodine requirements and the risks and benefits of correcting iodine deficiency in populations. J Trace Elem Med Biol 2008 22 81. 

Coulometric titration is used to determine relatively low concentrations of water (10. ig to 10 mg) and requires two reagents a catholyte and an anolyte (the generating solution). The iodine required for the reaction is generated in situ by the anodic oxidation of iodide. 

Titration of the iodine required 823 p,L of 0.098 8 M thiosulfate. Calculate the number of serine plus threonine residues per molecule of protein. Answer to the nearest integer. 

Assay Mix about 1.5 g of sample, accurately weighed, with 100 mL of recently boiled and cooled water contained in a 250-mL Erlenmeyer flask, add phenolphthalein TS, and titrate with 0.5 N sodium hydroxide to the first appearance of a faint-pink endpoint that persists for at least 30 s. Each milliliter of 0.5 N sodium hydroxide is equivalent to 37.04 mg of C3H602. Aldehydes (as propionaldehyde) Transfer 10.0 mL of sample into a 250-mL glass-stoppered Erlenmeyer flask containing 50 mL of water and 10.0 mL of a 1 80 aqueous solution of sodium bisulfite, stopper the flask, and shake vigorously. Allow the mixture to stand for 30 min, then titrate with 0.1 N iodine to the same brown-yellow endpoint obtained with a blank treated with the same quantities of the same reagents (see General Provisions). The difference between the volume of 0.1 N iodine required for the blank and that required for the sample is not more than 1.75 mL. 

TICI3 Concentration. The stoichiometry of the iodination requires a concentration of TICI3 at least six times as great as the iodide concentration for maximum yield. Higher levels do no apparent harm. 

The amount of iodine required is presumed to vary according to the presence of variable amounts of hydrogen sulfide and to the extent of oxidation by atmospheric oxygen. In one unsatisfactory preparation in which a relatively large amount of hydrogen sulfide must have remained in the solution a total of 493 g. (1.94 moles) of iodine was required and the final product contained free sulfur. 

A solution of sodium thiosulfate was standardized by dissolving 0.1210 g KIO3 (214.00 g/mol) in water, adding a large excess of KI, and acidifying with HCl. The liberated iodine required 41.64 mL of the thiosulfate solution to decolorize the blue starch/iodine complex. Calculate the molarity of the Na2S203. 

A 0.1017-g sample of KBrOj was dissolved in dilute HCl and treated with an unmeasured excess of KI. The liberated iodine required 39.75 mL of a sodium thiosulfate solution. Calculate the molar concentration of the Na2S203. 

The number of grams of iodine that react with 100 grams of oil is called the iodine number. In one case, 43.8 g of I2 was treated with 35.3 g of corn oil. The excess iodine required 20.6 mL of a 0.142 MNa2S203 for neutralization. Calculate the iodine number of the corn oil. 

The normal daily iodine requirement is 65 to < 75 pg, equivalent to 1 pg kg body weight or to 220 pg I per kg consumed DM (Anke 2004a, Anonymous 1996). The daily recommended iodine intake is much higher, at 200 pg. 

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