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Author: Subject: high-purity Mg needed for Grignards?
Hjalmar_Poelzig
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[*] posted on 12-5-2004 at 02:32
Have you read the patent?


Obviously not :D
Get your lazy ass up and read it! ;)

They use 1% of the weight of magnesium.

Any nitro or nitrate compound will do, as they list hundreds of them. I would use KNO3 however, have a look at the table in the experimental section.

Haven't tried it (yet).
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acx01b
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[*] posted on 12-5-2004 at 03:39


what is the reaction ?

no3- + ?
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Hjalmar_Poelzig
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[*] posted on 12-5-2004 at 04:53
the nitrate salt has a catalytic effect


So the nitrate salt does not get consumed.

I don't know exactly why it does have this promoting effect.

I have tried to search on scirus for other papers by the author but it doesn't turn up much.

Too bad I don't have SciFinder access anymore :(
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euxy
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[*] posted on 10-9-2010 at 11:29


An attempt to prepare phenyl magnesium chloride as per patent US2816937 was made.

An apparatus consisting of 1l RB flask, reflux condenser, heating mantle and magnetic stirrer was used.
The flask was charged with

0,15 mol Mg turnings
0,75 mol of chlorobenzene (5molar excess)
a knife tip of potassium nitrate

condeser had a cotton wool plug.

No special precautions against moisture were taken. The chlorobenzene was pure grade, fresh opened bottle, not dried. Mg was bright and grinded quickly in a mortar, then transferred into flask.

The patent procedure was strictly adhered to.

After 5hrs refluxing still nothing happened.The reaction should become green coloured. A iodine crystal was added, the solution went pink and discoloured approx. in 3 hrf of reflux. In the last attempt 2ml IPA was added with a little I2 but still nothing. After one day of boiling i gave up.

The patent states nothing about drying or the moisture sensitivity of this rxn. They used technical grade chemicals.

Has anyone encountered this problem when performing this patented method?

Any help will be appreciated.
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