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Author Topic: grignard  (Read 1986 times)

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Data

  • Guest
grignard
« on: June 14, 2002, 02:38:00 AM »
I have been doing a bit of reasearch on the grignard reaction and ive noticed that no one has discussed the matter of using either from starting fluid for the grignard reaction.If they did i mist it.So can either from starting fluid be used in the grinard.If so is there a cleaning method apart from just distilling.
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Rhodium

  • Guest
You MUST distill it, that's for sure.
« Reply #1 on: June 14, 2002, 02:43:00 AM »
You MUST distill it, that's for sure. Other than that, you should dry it really thoroughly, either over NaOH or KOH, or preferably over sodium wire (but I guess you don't have access to that).
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Data

  • Guest
grignard
« Reply #2 on: June 14, 2002, 03:51:00 AM »
Ok, what is happening when the idine is added, the grignard reaction start's but then stops. everything left looks like mud water.
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Rhodium

  • Guest
The iodine helps by making the more reactive ...
« Reply #3 on: June 14, 2002, 04:02:00 AM »
The iodine helps by making the more reactive alkyl iodide from the alkyl halide, and also by reacting with the oxide coating of the magnesium.

If it starts and then stops again, you probably have wet solvent, and you need to find a more powerful drying agent.
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Data

  • Guest
NaOH
« Reply #4 on: June 14, 2002, 07:29:00 AM »
After searching i found that alot of bees say NaOH is no good for drying Ether but then some say it is.
Is ther a method for this or is it a simpul wash.
if there is any NaOH left in the grignard will it stuff things up.
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lugh

  • Guest
USP Ether
« Reply #5 on: June 14, 2002, 02:00:00 PM »
The procedure mentioned in

Post 247093

(lugh: "Re: Drying Ether With NaOH", Chemistry Discourse) uses USP ether, which isn't the same thing as starting fluid. Starting fluid often primarily contains aromatic hydrocarbons, not diethyl ether, and propellants. Aromatic hydrocarbons won't support a grignard reaction  :(
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El_Zorro

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the starting fluid that comes in a spray can and ...
« Reply #6 on: June 16, 2002, 03:31:00 AM »
the starting fluid that comes in a spray can and says '50% ether' most definately contains diethyl ether.  I kinda like to light a little fire and then spray some at it and watch it make a small little explosion in the open air.  But I'm just weird that way. ::)   I would say spray that out, wash it with water, then distill it, and dry it.  That'd be about the best you could do.

Edit:Actually, I had a thought.  What about dumping in some CaO and then distilling?  If the other drying agents aren't hygroscopic enough to get the water out, will it not react with the CaO?

Do not go gentle into that good night.  Rage, Rage, against the dying of the light.  --Dylan Thomas

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