CHEM 269 Lecture Notes - Lecture 10: Propiophenone, Acetophenone, Spatula
30 Jun 2016
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Purpose: to identify an unknown liquid as an aldehyde, ketone, or alcohol by carrying out classification tests, preparing a solid derivative of the unknown, getting a melting point, and analyzing the nmr spectrum of the unknown. In a reaction tube, add 2ml of dnp reagent (2,4-nitrophenylhydrazine dissolved in. H3po4 and etoh) and 2ml of unknown, and then mix thoroughly. Keep at room temper- ature for a few minutes, and observe if precipitate forms. If no precipitate forms, then un- known is alcohol, so move onto ceric nitrate test. If precipitate forms, test is positive, which indicates unknown is aldehyde/ketone. The precipitate should be collected via suc- tion filtration and washed with water until indicator paper turns purple. To 3 reaction tubes, add 0. 7ml of schiff"s reagent, and 0. 1ml of compound to be tested. Three tests will be run: benzalaldehyde will give positive result (magenta hue), acetone gives negative result (pale pink), then compare the result of unknown.
