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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: zeoblade on May 20, 2011, 10:08:32 PM

Title: Hydration inactivating FeBr3 in Electrophilic Aromatic Substitution
Post by: zeoblade on May 20, 2011, 10:08:32 PM

In a section on halogenation of benzene, a question asks, "why does hydration inactivate FeBr3?"

Maybe I can't understand what they are asking. Are they asking to add water to benzene? Or hydrating FeBr3?

Water coordinating to Fe as a ligand will inactivate FeBr3 to catalyse halogenation of benzene?

Title: Re: Hydration inactivating FeBr3 in Electrophilic Aromatic Substitution
Post by: Schrödinger on May 21, 2011, 02:23:27 AM

Well, I'm guessing that H2O, as you said binds to FeBr3, which is a Lewis acid, and prevents breakdown of the Br-Br bond.
    Br2 + FeBr3 = Br+ + [FeBr4]-
   The above reaction might not occur due to the absence of FeBr3

Please correct me if I'm wrong.