Organic 2 Review Problem 513

Organic 2 Review Problem 513 - QUANTITATIVE ANALYSIS 497...

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Unformatted text preview: QUANTITATIVE ANALYSIS 497 10-76 x 14 x 0-025 x I 0 .'. ioo g. glycine contain g. nitrogen iooo X 0*02035 = 18-5%. Theoretical for C 2 H 5 NO 2 ; 18-7% N. Substances suitable for the estimation: acetanilide, diphenylamine, giycine, benzanilide. Estimation of Methoxyl (CH 3 O-) Groups. (ZeisePs Method.) Principle. A definite amount of the substance (ca. 25 mg.) is weighed out and transferred to the reaction bulb of the apparatus where it is decomposed by refluxing with constant-boiling hydriodic acid, the essential reaction being: R-OCH 3 + HI > R-OH + CH 3 I The 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 AgI, 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...
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This note was uploaded on 09/19/2011 for the course CHM 2211 taught by Professor Castalleano during the Fall '06 term at University of Florida.

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