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Oxidizing Alkyl substituents on Benzene (-1 C?)

Discussion in 'DAT Discussions' started by bchang57, Feb 17, 2012.

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  1. bchang57

    bchang57

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    According to DAT Achiever, a benzene ring with an ethyl at C-1, and a methyl at C-4 undergoes oxidation with NaCr2O7, H+, and heat to yield a benzene ring with 2 COOH groups at the 1 and 4 position.

    I thought the methyl would become COOH and the ethyl would become CH2COOH.

    Does someone know the reason as to why the ethyl group loses a carbon?
  2. Msmouth

    Msmouth

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    The COOH goes on the benzylic carbon (closest to the ring) every time, and it doesn't matter how long the chain is.
  3. Dotoday

    Dotoday

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    This is a side chain oxidation reaction. Whenever you have a benzylic carbon with a benzylic hydrogen, it gets oxidized to cooh using Group 1 metal with MnO4 or K2Cr2O7. Hope this helps.

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  4. bchang57

    bchang57

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    ahh im still lost as to why the ethyl becomes COOH instead of CH2COOH
  5. Msmouth

    Msmouth

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    The benzyllic carbon is the carbon closest to the benzene ring......no matter how long the chain is, the COOH will be 1 away from benzene and the rest will disappear.
  6. Dotoday

    Dotoday

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    Yes. It is like a tree branch that has little branches. Once you cut the big branch off, all the little branches will go with it.

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