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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: zeoblade on May 20, 2011, 10:52:05 PM

Title: Friedel-Crafts Acylation of Benzene
Post by: zeoblade on May 20, 2011, 10:52:05 PM

After you add the acylium ion and the carbonyl oxygen complexes AlCl3, water is added to release the product.

Is this the same reason with NaBH4 reduction of ketones?

Title: Re: Friedel-Crafts Acylation of Benzene
Post by: Schrödinger on May 21, 2011, 02:33:35 AM

http://www.chem.ucalgary.ca/courses/351/Carey5th/Ch15/ch15-2-6.html

The above link is for LiAlH₄, but I think the mechanism for NaBH₄ is similar to this.

Title: Re: Friedel-Crafts Acylation of Benzene
Post by: zeoblade on May 21, 2011, 02:39:24 AM

Thank you,

So does this mean you also think adding water to release the ketone from AlCl₃ is the same as adding water when reducing a ketone with NaBH₄?

I'm just not very sure about the mechanism of how the water releases the ketone produced from Friedel-Crafts acylation of benzene

Title: Re: Friedel-Crafts Acylation of Benzene
Post by: BluePill on June 03, 2011, 07:32:51 AM

I am not sure if you really need water in Friedel-Crafts acylation. I thought (by my reckoning) that AlCl₃ requires anhydrous conditions.

If I remember my inorganic chemistry right, AlCl₃ is ionic. Therefore, it would a complex in the presence of water (which I think is undesirable considering that you need AlCl₄^- in the end).

Title: Re: Friedel-Crafts Acylation of Benzene
Post by: Schrödinger on June 06, 2011, 04:18:27 AM

Yes. AlCl3 requires anhydrous conditions.
But I don't think AlCl3 is ionic, although it's aqueous solution is.