ZHANGNIUBI
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Need some help about α-Bromination
Hey,guys, I m in trouble with this problem:
when using CH3OH as solvent and Br2, the major production is the first one, and when CCl4 as solvent and Br2, the major production is the second one.
I cant figure out why.
Thank you
[Edited on 17-9-2011 by ZHANGNIUBI]
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ZHANGNIUBI
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That may be about the differences between kinectic production and thermodynamic production. But what is the real reason?
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francis
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Will you post the picture again please? The link doesn't seem to work.
Or just write the names of the products if you can.
The reason is because of the difference in solvent polarity: methanol is a polar solvent, and CCl4 is a nonpolar solvent.
If you are talking about alpha-bromination of a carbonyl, the enolate intermediate will be stabilised by a polar solvent. I don't know if an enolate
forms without the presence of acid or base.
If you post the image again, it would be helpful
[Edited on 17-9-2011 by francis]
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drago57
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Are you excluding light from your reactions? Bear in mind even a fluorescent strip light will be enough to photolyse Br2
I'm wondering if your reaction in CCl4 is going via a radical mechanism whilst the rection in MeOH is going via the enolate intermediate. Try them
again with your flasks wrapped in foil and see what you get out of that
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ZHANGNIUBI
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thank you, guys,here is the document. And the the light was not mentioned..it seems like it s about how solvent control the major production..
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Nicodem
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Quote: Originally posted by ZHANGNIUBI  | | when using CH3OH as solvent and Br2, the major production is the first one, and when CCl4 as solvent and Br2, the major production is the second one.
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In the first post you make it sound like you ask about your own experimental results, but don't provide us the experimental and analytical data. In
the later post you make it sound like you are asking about a literature example, but you don't provide the reference. In any case you are not giving
sufficient data!
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