3 oxidation reaction

3 oxidation reaction - Experiment#3 Cyclohexanone by...

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Unformatted text preview: Experiment #3 Cyclohexanone by Hypochlorite Oxida8on Oxida8on States •  Easy for inorganic salts: –  CrO42 ­ reduced to Cr2O3. –  KMnO4 reduced to MnO2. •  Oxida&on: Gain of O, O2, or X2; loss of H2. •  Reduc&on: Gain of H2 (or H ­); loss of O or O2; and loss of X2. •  The gain or loss of H+, H2O, HX, etc. is neither an oxida8on nor a reduc8on. 2 Oxida8on States of Carbons 3 Oxida8on of 2° Alcohols •  2° alcohol becomes a ketone. •  Oxidizing agent is Na2Cr2O7/ H2SO4. •  Ac8ve reagent probably is H2CrO4. •  Color change is orange to greenish ­blue. 4 Oxida8on of 1° Alcohols to Carboxylic Acids •  Chromic acid reagent oxidizes primary alcohols to carboxylic acids. •  The oxidizing agent is too strong to stop at the aldehyde. 5 Pyridinium Chlorochromate (PCC) •  PCC is a complex of chromium trioxide, pyridine, and HCl. •  Oxidizes primary alcohols to aldehydes. •  Oxidizes secondary alcohols to ketones. 6 3° Alcohols Cannot Be Oxidized •  Carbon does not have hydrogen, so oxida8on is difficult and involves the breakage of a C—C bond. 7 Other Oxida8on Reagents •  •  •  •  •  •  •  CuO, 300°C (industrial dehydrogena8on) Collins reagent: Cr2O3 in pyridine Jones reagent: chromic acid in acetone KMnO4 (strong oxidizer) Nitric acid (strong oxidizer) Sodium hypochlorite; NaOCl Swern oxida8on: dimethylsulfoxide, with oxalyl chloride and hindered base, oxidizes 2° alcohols to ketones and 1° alcohols to aldehydes. 8 Hypochlorite Oxida8on Reac8on Mechanism Chemical Tests •  Chemical tests are oaen used to iden8fy the presence of func8onal groups. •  The carbonyl group in aldehydes & ketones can usually be detected by reac8on with 2,4 ­dinitrophenylhydrazine. •  Decomposi8on by acid •  The product of this reac8on is typically an orange precipitate, which can be collected by filtra8on. •  Similar decomposi8on by reac8on with base Procedure Notes •  No new techniques in this experiment •  Work in the HOOD, especially during the extrac8on! •  Must calculate yield ­see p. 23 Zubrick (8e) text if having trouble ...
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