Polynuclear Aromatics. Napthalene Naphthalene: nomenclature: Mono substituted:α-1- β- 2- Special...

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Polynuclear Aromatics P henanthrene Anthracene Naphthalene
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Transcript of Polynuclear Aromatics. Napthalene Naphthalene: nomenclature: Mono substituted:α-1- β- 2- Special...

  • Slide 1
  • Polynuclear Aromatics
  • Slide 2
  • Napthalene
  • Slide 3
  • Naphthalene: nomenclature: Mono substituted:-1- - 2- Special names:
  • Slide 4
  • Heat of hydrogenation is 61 Kcal/mole lower than predicted (resonance stabilization energy). Benzene is 36 Kcal/mole lower than predicted. - 61 = - 36 - 25 the second aromatic ring is less stable.
  • Slide 5
  • Naphthalene, reactions: 1) oxidation:
  • Slide 6
  • Note: Because naphthalene is sensitive to oxidation, you cannot make naphthoic acids via oxidation of a side chain.
  • Slide 7
  • 2. Reduction:
  • Slide 8
  • 3. Electrophilic Aromatic Substitution:
  • Slide 9
  • Electrophilic aromatic substitution (cont.)
  • Slide 10
  • Why is EAS in naphthalene mostly to the alpha-position?
  • Slide 11
  • EAS in syntheses of substituted naphthalenes: Alpha-substitution via halogenation or nitration.
  • Slide 12
  • Beta-substitution via high temp sulfonation or Friedel-Crafts acylation in nitrobenzene.
  • Slide 13
  • EAS in substituted naphthalenes: a)With an activating group to EAS in the alpha position 4- plus a little 2- in the beta position 1- b)With a deactivating group to EAS the other ring, usually alpha ( 5- & 8- )
  • Slide 14
  • Slide 15
  • Slide 16
  • Haworth Synthesis of naphthalene
  • Slide 17
  • Substituted naphthalenes via Haworth synthesis:
  • Slide 18
  • Slide 19
  • Slide 20
  • Slide 21
  • Oxidation:
  • Slide 22
  • Reduction:
  • Slide 23
  • EAS in anthracene or phenanthrene yields mixtures and is not generally useful. For example, in sulfonation:
  • Slide 24
  • Slide 25
  • Haworth synthesis of anthracene
  • Slide 26
  • Haworth synthesis of phenanthrene