The Vespiary

The Hive => Methods Discourse => Topic started by: pHarmacist on December 22, 2002, 05:34:00 AM

Title: Synthesis of Iodobenzene/Chlorobenzene in one pot
Post by: pHarmacist on December 22, 2002, 05:34:00 AM

A mixture of 22.8 g of benzene (0.3 moles), 27.5 g of iodine monochloride (0.169 moles), and 2.0 g of tungstated zirconia calcined at 800 DEG C. for 3 hours was stirred for 20 minutes at 20 DEG C. A copious quantity of HCl off-gassed from the reaction mixture. A GC of the reaction mixture indicated 41% conversion of benzene to a 1.3:1 mixture of chlorobenzene and iodobenzene.

Patent US6225514 (http://l2.espacenet.com/dips/viewer?PN=US6225514&CY=gb&LG=en&DB=EPD)

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Title: And your point is?
Post by: Rhodium on December 22, 2002, 05:44:00 AM

So by using a very expensive reagent and a specialized, hard to prepare catalyst, you can get a 41% yield of a mixture of relatively cheap, commercial products while releasing large amounts of corrosive gasses?

I'm sorry, but I don't think I have seen such a useless synthesis in a long time...  ::)

Title: hehe
Post by: pHarmacist on December 22, 2002, 05:49:00 AM

Don't be sorry.   ;D  I found it interesting that both could be made in one reaction vessel at the same time. Yield sucks, yeah... hehe... But then again, you can just order them :)

Hey! Maybe we can use this as a novel HCl(g) generator for chrystallisations LOL!

EDIT:
Iodobenzene is to prefer in most cases over chlorobenzene.  A better way of making it is:

Post 380729 (https://www.thevespiary.org/talk/index.php?topic=11981.msg38072900#msg38072900)

(pHarmacist: "Iodobenzene by direct benzene iodination", Novel Discourse)

Looking up prices online at various chem suppliers makes me wonder if this realy isn't the most useless/stupid synthesis around..

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