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Topic: Acetic anhydride  (Read 26870 times)

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Offline limpet chicken

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Acetic anhydride
« on: July 04, 2005, 12:56:31 PM »
I will soon have need of some acetic anhydride, or acetyl chloride for a reaction I am testing out, but am running into a few problems, I have a source, but I really don't wish to order acetic anhydride, it is one of the very few things I am sketchy about ordering, just a few things like phenylacetic acid, phenylacetone, acetic anhydride, benzyl cyanide, safrole etc, things like that I really wouldn't like to order, even in the UK.

Problem is, I haven't the space at the moment, to run a ketene lamp, and I don't wish to BUY AA, so, I wish to pick a few brains as to the best method.

What about, oxidising anhydrous ethanol to acetaldehyde with permanganic acid, then reducing the anhydrous aldehyde thus formed with a reducing agent, say, sodium dithionite in a solvent-free procedure?

Would this work well enough? yields are reasonably inportant, given the price of anhydrous ethanol? I might just buy some mineralised denatured EtOH, decolorise by shaking over anhydrous NaOH, flush out any pyridine w/ HCl, then distil off most of the methanol.

Any better ideas? if anyone has good UK sources for AA that you trust, I would appreciate a PM ;)

Thanks.
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Offline lemonoman

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Re:Acetic anhydride
« Reply #1 on: July 04, 2005, 01:48:05 PM »
We were taught a couple different ways to 'make' anyhydrides.  To make acetic anhydride, in particular...

One was to simply heat acetic acid (glacial) - so that

CH3COOH + CH3COOH <==> CH3COOOCH3 + H2O

[although this doesn't SEEM like it would work...and heating acids isn't the best idea in the world either]

Another way was to react a carboxlic acid with an acid chloride
CH3COOH + CH3COCl --> CH3COOOCCH3 + HCl

Which requires 'acetyl chloride' as you mentioned you didn't have.  So...how to make THAT...

How about


or

or


(all from ChemGuide)

Hope this helps...

Offline limpet chicken

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Re:Acetic anhydride
« Reply #2 on: July 04, 2005, 02:25:40 PM »
I would rather avoid using phosphorus halides.


Glacial acetic acid forms an azeotrope with H2O, so heating will not work, also AA is flammable, and an AA fire is NOT something I want to be close to ;D
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Re:Acetic anhydride
« Reply #3 on: July 05, 2005, 09:44:07 AM »
GAA+oxallyl chloride+catalytic DMF, rt
this is a common lit. prep, but i dont have a reference now.  you should easily be able to find one.


Offline movies

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Re:Acetic anhydride
« Reply #4 on: July 05, 2005, 04:57:30 PM »
just a few things like phenylacetic acid, phenylacetone, acetic anhydride, benzyl cyanide, safrole etc, things like that I really wouldn't like to order, even in the UK.

Heh, I just think it's funny that I have three of the five chemicals that you mentioned sitting on my lab bench right now.  Four if you count acetyl chloride.

Offline Dude

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Re:Acetic anhydride
« Reply #5 on: July 05, 2005, 05:14:17 PM »
Grad school always has the best inventory.  All of the necessary components were on the shelf (methylamine, phenylacetone, etc) without even an inventory list.  I was ready to set up shop and make about 4 Kg (based upon what was available) if I wasn't on pace to pass my cumulative exams.  Unfortunately, I passed them easily, wussed out, graduated and went about getting money the tedious way (working).  

Offline limpet chicken

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Re:Acetic anhydride
« Reply #6 on: July 05, 2005, 06:57:55 PM »
Damn man, that brings back memories, I haven't had prope dope for years, not since I was about 13, only ever had RP/I2 reduced ice recently.

Uggh, the smell of phenylacetic acid though, it sticks around for days, stinks like stale cat piss ;D

Movies, nice inventory, bet you have at least once been tempted haven't you ;) not that law abiding ppl like us would do such a thing though.

I think psudoephedrine is on its way out, what with the latest inclusions of PEGs and those nasty cellulose gakks in anything above white 8s, P2P, or L-PAC via biosythesis from benzaldehyde are the way of the future, lets see the DEA try to control 'phed when the hillbillies are biosynthesising their own!
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Offline movies

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Re:Acetic anhydride
« Reply #7 on: July 05, 2005, 07:04:44 PM »
Movies, nice inventory, bet you have at least once been tempted haven't you ;) not that law abiding ppl like us would do such a thing though.

Definitely tempting.  We just got some new lab space in the basement of the building so we were all joking about what we were going to do to pay for all the new equipment down there.  Seems obvious enough!

Offline jdurg

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Re:Acetic anhydride
« Reply #8 on: July 05, 2005, 10:33:16 PM »
Ahhh limpet.  I sincerely hope you're not going to be using your acetic anhydride with something you've obtained from your garden in an attempt to make a devil of a compound.  I know you know that stuff is incredibly horrible and one of the worst discoveries ever made, so I'm going to assume that you're not.   ;) ;D
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Offline hmx9123

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Re:Acetic anhydride
« Reply #9 on: July 06, 2005, 02:45:17 AM »
Hey now, AA has plenty of uses outside of the drug-manufacture industry.  Like the synthetic high energy-density materials industry. :)  Helps to make a fantastic nitrating agent.

Offline Borek

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Re:Acetic anhydride
« Reply #10 on: July 06, 2005, 04:14:58 AM »
Ahhh limpet.  I sincerely hope you're not going to be using your acetic anhydride with something you've obtained from your garden in an attempt to make a devil of a compound.

Red flower on a very thin leg?

That was my first idea too when limpet chicken asked about AA.

But IIRC he stated he is afraid of shots. Or was it jdurg?
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Offline limpet chicken

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Re:Acetic anhydride
« Reply #11 on: July 06, 2005, 09:05:29 AM »
Don't worry people, SWIM isn't about to be fiddling with his poppies (doesn't that sound wrong ;D), for some reason, they always seem mysteroiously to get scratches and cuts on the heads, but SWIM wouldn't cut them intentionally.

Besides, one of his friends would have SWIMs head on a plate if he went synthing that certain compound Jdurg mentioned.

And Borek, you are right, I can't stand needles, doesn't prevent insufflation, plugging or smoking though lmao :P

I have legitimate reasons other than heroin, to be making AA, put it that way :)
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Offline jdurg

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Re:Acetic anhydride
« Reply #12 on: July 06, 2005, 09:46:51 AM »
I'm an insulin dependent diabetic.  Let's just say that needles don't bother me at all.   ;D
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