[Benzoic Acid]

Hello, would potassium permanganate just dehydrate an alkane to form an alkene? Also could anyone point me into a direction on how pyridinium hydrobromide perbromide, brominates an alkene? Do the bromines just add to both carbons involved in the double bond, or is it an allylic type bromination?


My carey and williamson books have left me pretty helpless with these reagents.

thanks

[Alberto_Kravina]

Hello, would potassium permanganate just dehydrate an alkane to form an alkene?

Dehydration is a reduction, permanganate is a strong oxidizing agent, it can't dehydrate an alkane, so there is something wrong.

[FeLiXe]

dehydration is an oxidation:

C^(-III)H₃-C^(-III)H₃ - H₂ ->
C^(-II)H₂-C^(-II)H₂

carbon is oxidized and the substance that reacts with  H₂ is reduced

--

I don't think permanganate reacts with alkanes. If it did form an alkene, the alkene would be much more reactive and you'd only get the diole.

[movies]

Dehydration is neither an oxidation nor a reduction.  It's just loss of water.

Dehydrogenation is an oxidation (e.g., alkane to alkene)

[Alberto_Kravina]

Dehydration is neither an oxidation nor a reduction.  It's just loss of water.

Sorry movies, this is a germanism.
In German Dehydrogenation is spelled "Dehydrierung"....stupid germanism....

[movies]

Dehydration is neither an oxidation nor a reduction.  It's just loss of water.

Sorry movies, this is a germanism.
In German Dehydrogenation is spelled "Dehydrierung"....stupid germanism....

Heh, that's okay.  Lots of subtleties get lost in translation, I'm sure!