Oxime titration

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The oxime titration is a titration method for the quantitative determination of aldehydes (R 1 = Organylgruppe, eg., Alkyl group, R 2 = H) or ketones (R 1 , R 2 = Organylgruppe, eg., Alkyl group). The carbonyl compound 1 reacts under acid catalysis with protonated hydroxylamine 2 to form an oxime 3 .

Usually 2 is used as hydroxylamine hydrochloride .

Oxime titration V.2.svg

The amount of oxonium ions 4 equivalent to the aldehyde / ketone can be determined by titration with sodium hydroxide solution or potassium hydroxide solution (c = 0.5 mol / l). To determine the end point of this titration, indicators such as methyl orange or bromophenol blue , whose transition point is around pH 3.5 , are particularly suitable , since otherwise excess hydroxylamine hydrochloride would also be recorded.

literature

  • E. Ehlers: Analytics II . 9th edition. Deutscher Apothekerverlag Stuttgart, 1999, ISBN 3-7692-2488-4 .