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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: pixie on October 17, 2005, 04:06:30 PM

Title: bromination with AlCl3?
Post by: pixie on October 17, 2005, 04:06:30 PM

On looking at the mechanism of bromination of benzene I was wondering if it was possible to brominate using AlCl3 instead of AlBr3 as catalyst. What do you think? Is it possible?

Title: Re:bromination with AlCl3?
Post by: movies on October 17, 2005, 08:39:00 PM

There is the risk of chlorinating benzene instead of brominating when you use AlCl₃.  In reality, however, I think it still works out pretty well.  Another, possibly more common, Lewis acid for aromatic bromination is FeBr₃.  You can also use acetic acid sometimes.

Title: Re:bromination with AlCl3?
Post by: pixie on October 18, 2005, 12:54:42 PM

How is it possible to chlorinate? Isnt it that the delta positive Br  attacked by benzene and the delta negative Br goes to the ALCl3?

Title: Re:bromination with AlCl3?
Post by: movies on October 18, 2005, 06:20:23 PM

Yeah, you're right.  It is possible that there are chlorides floating around that could swap in as well though.