redfish
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Williamson Ether Synthesis of Acetic Anhydride
So I was thinking about alternative syntheses of acetic anhydride, and I stumbled upon the williamson ether synthesis method. Do you think this could
work to synthesize acetic anhydride? In case you're not familiar with the method, it combines an alkyl halide and an alkoxide to form an ether. Since
acetate is an alkoxide, theoretically all you'd have to do is mix acetyl chloride or similar with acetic acid, and you'd get the mineral acid of the
halide and acetic anhydride, right?
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barley81
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Acetic acid is not an alcohol, acetate is not an alkoxide, and acetyl chloride is not an alkyl halide. Acetic acid is a carboxylic acid! The
Williamson ether synthesis has nothing to do with the synthesis of acetic anhydride.
However, acetic anhydride <i>can</i> be prepared by the combination of sodium acetate and acetyl chloride. There is a thread on this forum
concerning that procedure.
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Lambda-Eyde
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I think people are having a harder time getting acetyl chloride or its precursors than acetic anhydride. I have never seen anyone on SM say that they
have prepared or used acetyl chloride in an amateur setting.
This just in: 95,5 % of the world population lives outside the USA
Please drop by our IRC channel: #sciencemadness @ irc.efnet.org
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Magic Muzzlet
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I have used AcCl to prepare Ac2O in an amateur setting, from NaOAc which works great. More info is also at versuchschemie and LambdaSyn I believe, but
now you have heard it!
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Lambda-Eyde
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Quote: Originally posted by Magic Muzzlet  | | I have used AcCl to prepare Ac2O in an amateur setting, from NaOAc which works great. More info is also at versuchschemie and LambdaSyn I believe, but
now you have heard it! |
How did you prepare or acquire the acetyl chloride? That's the interesting part.
This just in: 95,5 % of the world population lives outside the USA
Please drop by our IRC channel: #sciencemadness @ irc.efnet.org
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mnick12
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I don't know why everyone gets the impression AA and acetyl chloride are so difficult to come by. Many suppliers who ship to individuals often carry
acetic anhydride or acetyl chloride at some point. I purchased a liter of acetyl chloride a while back for about $100 dollars, and while I have not
seen any for sale recently acetic anhydride is always popping up.
Anyway yes AA can be made from anhydrous sodium acetate and an acetyl halide, but I would recommend a mechanical stirrer and watch out for charring.
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Magic Muzzlet
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Lambda-Eyde - The AcCl was just commercial material purchased from a chemical distributor. It would be totally impractical for me to make it myself. I
think people's paranoia about Ac2O being on a list is the only thing making it hard to get, not its actual availability.. Nowadays you can buy it in
the US without signing anything, so what is the problem.
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Nicodem
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Thread Moved
3-1-2013 at 10:27 |
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