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Side chain oxidation

Side chain oxidation. Lab 2 . Side chain. It’s the aliphatic portion of the alkylbenzene . . Benzylic Radicals and Cations. Free Radicals: An atom or group of atoms that has at least one unpaired electron ,so: Unstable Highly reactive . Benzylic Radicals and Cations.

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Side chain oxidation

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  1. Side chain oxidation Lab 2

  2. Side chain It’s the aliphatic portion of the alkylbenzene.

  3. Benzylic Radicals and Cations • Free Radicals: • An atom or group of atoms that has at least one unpaired electron ,so: • Unstable • Highly reactive

  4. Benzylic Radicals and Cations • Benzyl radical: is a specific name for the radical produces from the Hydrogen abstraction from the methyl group of methylbenzene (tolune).

  5. Benzylic Radicals and Cations • Benzylic radical: is the general name applies to all radicals that have unpaired electron on the side- chain carbon atom that attached directely to the benzene ring.

  6. Benzylic Radicals and Cations • Benzylic hydrogen atoms: is the hydrogen atom of the carbon atom that directly attached to the benzene ring.

  7. Benzylic Radicals and Cations • Benzyliccation: is the departure of a leaving group (LG) from a benzylic position.

  8. Benzylic Radicals and Cations • They have approximately the same stabilities, this stability can be explained by resonance theory.

  9. Halogenation of the side chain

  10. Bromination Chlorination

  11. Benzylichalogenation Chain Initiation Step 1 Chain propagation Step 2

  12. Benzylichalogenation Step 3 Chain Termination Step 4

  13. Oxidation of the side chain • The oxidation can be carried out by the action of hot alkaline potassium permanganate.

  14. Oxidation of the side chain • Oxidation of the side- chain take place initially at the benzylic carbon; alkylbenzenes with alkyl group longer than methyl are ultimately degraded to benzoic acids:

  15. Oxidation of the side chain • Reaction:

  16. Procedure: • Dissolve 1 gm NaOH in 75 ml of distal water in round flask (500ml). • Add 7 gm of potassium permanganatr KMnO4, and 4 ml of toluene. And heat it on hot plate for 3 hr.

  17. Procedure: • In case if the KMnO4 color don’t change, add few drops of ethanol until the violet color disappear. • Filtre by Buchner, take the filtrate and heat it until the volume reduced to 10- 20 ml.

  18. Procedure: • Cool the filtrate on a iced cold water, then add HCL drop wise until the ppt stop. • Fitre by Buchner.

  19. Thank you

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