Grignard reagent prep

thilo_wolfe · Thu Mar 17, 2005 4:39 am

The Grignard reagent employed in the second half of the reaction (phenyl magnesium bromide) is inevitably prepared within the laboratory, as it is felt that commercially prepared material is carefully watched. endquote

Any info/leads on preparing phenyl Mag bromide in the lab? I only found one commercial source (bells and whistles here!0 It was SA at $180 for 800 ml. And teh SA mol diagram did NOT seem to match the name(phenyl ring with ONE mol off it). This is for academic experiment NOT involving ANY controlled substances. But paying $180 for less that a liter of reagent goes against my grain. I found ONE reference to grig. reg prep in the hive archive (and it was responded to by rhodium) No hits otherwise. Im doing the digging, anyone know?

ApprenticeCook · DILLIGAF

Your kidding right?
Your doing academic work and cant prepare a grignard reagent?

Bromobenzene + Mg --> DEE --> PMB

... Anyway...
-AC

Lief · Thu Mar 17, 2005 5:25 am

This might be useful:
Preparation of phenyl magnesium chloride
http://v3.espacenet.com/pdfdocnav?DB=EPODOC&IDX=US2816937&F=128&QPN=US2816937

IndoleAmine · Dreamreader Deluxe

More exactly: aryl- and alkyl halides react with Mg under strictly anhydrous conditions (and preferably in ethereal, or other oxygen-containing nonpolar solvents like THF) to form metallorganic magnesium complexes (like phenylmagnesiumbromide); and if the grignard takes place, the Mg will insert between the halogen and hydrocarbon.

ethyl bromide in anhydrous ether will react violently to form ethylmagnesium bromide when coming into contact with Mg turnings suspended in anhydrous ether, for example.

Now go and figure out by yourself how this could work with phenyl bromide (sure you didn't mean benzyl bromide BTW?)... Wink

i_a

thilo_wolfe · Fri Mar 18, 2005 2:00 am

Thanks - the actual reagent desired was 4-chloro phenyl mag bromide.

The patent helped (react under reflux with nitrogen catalist).

On the third reply - how voilent is violent - are we talking large reaction vessel (like mercury fulminate) or just duck and cover and kiss Y. A. goodbye.

I need a bigger libruary.;. and I forgot the obvious - check US Pat office for prep patent.