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Author: Subject: Acetic anhydride preparation
Waffles SS
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[*] posted on 22-11-2018 at 22:03


Quote: Originally posted by clearly_not_atara  

I was expecting that Cu2+ would oxidize SO2.
Fe(OAc)3 may be a somewhat stronger oxidizer, but it is much harder to dry. AgOAc is easy to dry, but expensive and probably insoluble. Pb(OAc)4 is cheaper but toxic. Perhaps Fe2(SO4)3 could be used?


I didnt find any reference for making Ac2O by this method
(i think this is time that you test your idea and publish it)

[Edited on 23-11-2018 by Waffles SS]




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[*] posted on 11-7-2019 at 01:52


Has anyone actually tried the Sodium Pyrosulphate and Sodium Acetate method from the Henry Dreyfus patent? I have seen that some people have had success with it on another forum but it looked like it was quickly dismissed in this thread without anyone actually trying it.
It is also supposed to work with Propionate salts to get Prop. Anhydride.
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clearly_not_atara
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[*] posted on 11-7-2019 at 16:36


IIRC tests by SM members showed that the method does work for propionic anhydride but does not work for acetic anhydride.

One possibility is to use pyrosulfate to make benzoic anhydride and then react this with anhydrous metal acetate to get acetic anhydride. Benzoic anhydride is probably a good case for this rxn since it is not enolizable or easily oxidized. Also sodium benzoate can bee had in bulk and IIRC is not hygroscopic.

[Edited on 12-7-2019 by clearly_not_atara]




[Edited on 04-20-1969 by clearly_not_atara]
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[*] posted on 11-7-2019 at 23:32


Quote: Originally posted by clearly_not_atara  
IIRC tests by SM members showed that the method does work for propionic anhydride but does not work for acetic anhydride.

One possibility is to use pyrosulfate to make benzoic anhydride and then react this with anhydrous metal acetate to get acetic anhydride. Benzoic anhydride is probably a good case for this rxn since it is not enolizable or easily oxidized. Also sodium benzoate can bee had in bulk and IIRC is not hygroscopic.

[Edited on 12-7-2019 by clearly_not_atara]


I tried reaction of Pyrosulfate with acetate and propionate salt without any success.I will be so happy if someone show this method is not bullshit and Henry Dreyfus is not lier !

Ac2O from Benzoic anhydride is possible and i mentioned this method on page 33




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[*] posted on 4-8-2019 at 23:27


Quote: Originally posted by Waffles SS  
Quote: Originally posted by clearly_not_atara  
IIRC tests by SM members showed that the method does work for propionic anhydride but does not work for acetic anhydride.

One possibility is to use pyrosulfate to make benzoic anhydride and then react this with anhydrous metal acetate to get acetic anhydride. Benzoic anhydride is probably a good case for this rxn since it is not enolizable or easily oxidized. Also sodium benzoate can bee had in bulk and IIRC is not hygroscopic.

[Edited on 12-7-2019 by clearly_not_atara]




I tried reaction of Pyrosulfate with acetate and propionate salt without any success.I will be so happy if someone show this method is not bullshit and Henry Dreyfus is not lier !

Ac2O from Benzoic anhydride is possible and i mentioned this method on page 33


I have seen reports that the Propionic salt and Pyrosulphate has worked for people but I just tried it and it failed. Im unsure if I managed to get Pyrosulphate from Bisulphate though which may have been the problem.

What happened when you tried the propionic salt with pyrosulphate?

Has anyone here had success with the pyrosulphate method?


[Edited on 5-8-2019 by NZniceguy]
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[*] posted on 5-8-2019 at 04:24


Quote: Originally posted by NZniceguy  


What happened when you tried the propionic salt with pyrosulphate?



I just got something like propionic acid each time(I even used dry Merck pyrosulfate and propionic salt)

My advise : dont waste your time by this method




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[*] posted on 25-8-2019 at 03:22


Making acetic anhydride is very easy and straightforward if done safely using ketene. The key word here is SAFELY as ketene is on par with hydrogen cyanide. Just follow the setup that doug uses on dougs lab youtube channel or a variation of the setup. Ive had no problem using this method and if done safely it is extremely simple to achieve in a amature home lab with a fume hood. Ive also used the S2Cl2 and sodium acetate method which is also quite easy but a lot more work and messy/smelly because you have to synthesize the S2Cl2. I don't know why so many people ask about making acetic anhydride when its so simple to synthesize. I can also vouch that the pyrosulfate method is bullshit for acetic and for propionic anhydride. I had no luck with either i did however find propionic anhydride extremely simple to synth via ketene and propionic acid.
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[*] posted on 14-12-2019 at 09:10


Ok, I had another thought.

Suppose you gas HCl to a solution of succinic anhydride and GAA. The result should be an equilibrium between succinic monochloride and acetyl chloride (I think this leans left, but whatever):

AcOH + HOOCCH2CH2COCl <> AcCl + HOOCCH2CH2COOH

If this solution is heated, acetyl chloride should boil away first by Le Chatelier’s principle. It is dramatically more volatile than anything else in the flask.

This is particularly attractive because succinic anhydride can bee had by simply heating succinic acid to 200-250 C. See:

https://patents.google.com/patent/US3957830A/en

EDIT: this might also work for benzoyl chloride or [m]ethanesulfonyl chloride!

[Edited on 15-12-2019 by clearly_not_atara]




[Edited on 04-20-1969 by clearly_not_atara]
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[*] posted on 31-1-2020 at 07:20


2 Ideas:

Ozonolysis of acetylene

"Decomposition" of acetate salt

I know Wikipedia isn't necessarily a great source, but given the accessibility of both ozone and acetylene I think it's worth some thought. Given the fact that it would be a gaseous mixture of an explosive gas and an extremely strong oxidizer, I'm not recommending that anyone without the proper equipment and experience try.

Again from Wikipedia, heating anhydrous Zinc Acetate apparently releases Acetic anhydride in a vacuum, leaving the basic Acetate salt. A good enough vacuum might be hard to pull, but again due to the accessibility of acetate salts it may be worth a shot.
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[*] posted on 31-1-2020 at 07:30


Ozone + acetylene sounds like a really terrible idea.
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[*] posted on 31-1-2020 at 07:35


Quote: Originally posted by DavidJR  
Ozone + acetylene sounds like a really terrible idea.


It sounds like one of the worst ideas I have seen around here. If you want an explosion I would recommend TATP before I would recommend this one.
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[*] posted on 31-1-2020 at 10:36


Quote: Originally posted by Tsjerk  
Quote: Originally posted by DavidJR  
Ozone + acetylene sounds like a really terrible idea.


It sounds like one of the worst ideas I have seen around here. If you want an explosion I would recommend TATP before I would recommend this one.


Great minds think alike! So alike that I explicitly said it should not be attempted by anyone who's not equipped to deal with it. I can't tell if you actually think I want an explosion, but I'd rather sit on a nail than make TATP again. Do you have anything thoughts on the Acetate salt?

Given the fact that it would be a gaseous mixture of an explosive gas and an extremely strong oxidizer, I'm not recommending that anyone without the proper equipment and experience try.
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[*] posted on 31-1-2020 at 12:04


Wasn't this combo covered in Igntition? It wouldn't be above average for those nutjobs. But yeah, that sounds like premeditated *kaboom*.



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[*] posted on 31-1-2020 at 13:24


Quote: Originally posted by njl  
2 Ideas:

Ozonolysis of acetylene

"Decomposition" of acetate salt

I know Wikipedia isn't necessarily a great source, but given the accessibility of both ozone and acetylene I think it's worth some thought. Given the fact that it would be a gaseous mixture of an explosive gas and an extremely strong oxidizer, I'm not recommending that anyone without the proper equipment and experience try.

Again from Wikipedia, heating anhydrous Zinc Acetate apparently releases Acetic anhydride in a vacuum, leaving the basic Acetate salt. A good enough vacuum might be hard to pull, but again due to the accessibility of acetate salts it may be worth a shot.


Decomposition of zinc acetate has been brought up again and again, but nobody here seems to have actually heated zinc acetate at 2 mm pressure and 250 degrees C to try it out for themselves.

These the parameters quoted in old sources for this decomposition reaction.




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[*] posted on 31-1-2020 at 23:13


Quote: Originally posted by SWIM  
Quote: Originally posted by njl  
2 Ideas:

Ozonolysis of acetylene

"Decomposition" of acetate salt

I know Wikipedia isn't necessarily a great source, but given the accessibility of both ozone and acetylene I think it's worth some thought. Given the fact that it would be a gaseous mixture of an explosive gas and an extremely strong oxidizer, I'm not recommending that anyone without the proper equipment and experience try.

Again from Wikipedia, heating anhydrous Zinc Acetate apparently releases Acetic anhydride in a vacuum, leaving the basic Acetate salt. A good enough vacuum might be hard to pull, but again due to the accessibility of acetate salts it may be worth a shot.


Decomposition of zinc acetate has been brought up again and again, but nobody here seems to have actually heated zinc acetate at 2 mm pressure and 250 degrees C to try it out for themselves.

These the parameters quoted in old sources for this decomposition reaction.

If i have nothing going on, I might try it this weekend just for the fun of it. People like to suggest things, not read the thread and then not try it.




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[*] posted on 1-2-2020 at 21:55


Quote: Originally posted by Abromination  

If i have nothing going on, I might try it this weekend just for the fun of it. People like to suggest things, not read the thread and then not try it.


I feel that would be a most valuable contribution to the sum of knowledge on this fine forum. I eagerly await your results, should you perform this experiment. :cool:
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[*] posted on 2-2-2020 at 15:54


Quote: Originally posted by G-Coupled  
Quote: Originally posted by Abromination  

If i have nothing going on, I might try it this weekend just for the fun of it. People like to suggest things, not read the thread and then not try it.


I feel that would be a most valuable contribution to the sum of knowledge on this fine forum. I eagerly await your results, should you perform this experiment. :cool:

I will soon, but weekend was spent fumehood building. Ill read through the whole thread and do some more research first. I dont think it will work, but why not try




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[*] posted on 7-2-2020 at 13:00


Quote: Originally posted by byko3y  
I want to put an end to the discussion of distilling acetate for preparation for acetic anhydride.
https://www.sciencemadness.org/whisper/viewthread.php?tid=9&... - link to the original article on Zinc Acetate.
https://www.sciencemadness.org/whisper/viewthread.php?tid=9&... - report about results by very same Waffles SS.
Now let's look inside the article - at the mass spectrum graph they recorded:

Here I made a spectrum for 260°C :

Now let's take a look at the reference mass spectrum of acetic anhydride from NIST:

Do you see the similarity? Because I don't. How the hell could those douchebags find acetic anhydride in their spectrum - god only knows. Some more spectrums of possible reaction products for reference (major ions in orded of decreasing intensity):
http://webbook.nist.gov/cgi/cbook.cgi?ID=C108247&Mask=20... - Acetic anhydride: 43 (faint 42)
http://webbook.nist.gov/cgi/cbook.cgi?ID=C64197&Mask=200... - Acetic acid: 43, 45, 60 (15, 42)
http://webbook.nist.gov/cgi/cbook.cgi?ID=C67641&Mask=200... - Acetone: 43, small 58 (42, 15)
http://webbook.nist.gov/cgi/cbook.cgi?ID=C123422&Mask=20... - Diacetone alcohol: 43, small 58, 59 (101)
http://webbook.nist.gov/cgi/cbook.cgi?ID=C141797&Mask=20... - Mesityl oxide: 83, 55, 98, 43, small 29, 39 (a lot of faints)
http://webbook.nist.gov/cgi/cbook.cgi?ID=C630080&Mask=20... - Carbon monooxide: 28
http://webbook.nist.gov/cgi/cbook.cgi?ID=C124389&Mask=20... - Carbon dioxide: 44 (28, 16, 12)
http://webbook.nist.gov/cgi/cbook.cgi?ID=C7732185&Mask=2... - Water: 18, small 17
http://webbook.nist.gov/cgi/cbook.cgi?ID=C74828&Mask=200... - Methane: 16, 15, small 14, 13
http://webbook.nist.gov/cgi/cbook.cgi?ID=C74840&Mask=200... - Ethane: 28, small 27, 30, 26, 29
http://webbook.nist.gov/cgi/cbook.cgi?ID=C75070&Mask=200... - Acetaldehyde: 29, 44, 43, 15, small 42, 14
(there're similar spectrums on restek website, e.g.
http://www.restek.com/compound/view/67-64-1/Acetone - Acetone
http://www.restek.com/compound/view/123-42-2/Diacetone%20alc... - Diacetone alcohol )

Now let's try to analize the spectrum of gaseous products at 260°C: 15, 43, 16, 44, 45.
15 m/z is a methyl ion CH3+.
16 m/z is not oxygen but methane ion CH4+. Prevalence of it together with 15 m/z means methane is a major product. The fact that intensity at 15 is higher than 16 means there are other methyl-producing substances.
44 m/z is a carbon dioxide ion CO2+. CO2 is another major product of the reaction.
There's no 18 ion meaning no water detected. That could be explained by the fact decarboxylative ketonization does not generate water but carbon dioxide is produced instead.
45 m/z is an unknown ion. It could be acetaldehyde, but this substance has a very distinctive 29 ion which was not detected by authors. Acetic acid has smaller ion 45, but it also has a smaller definite 60 ion, which was not detected too. My guess: 60 m/z ion was ignored for some reason (small relative intensity?) and acetic acid is formed in substantial amounts.
43 m/z is acetyl CH3CO+. Could be derrived from any molecule with acetyl fragment. Probably that's acetone and diacetone alcohol which both have much smaller other ions.
I'd guess the detected products were methane, CO2, acetone, diacetone alcohol, small amount of acetic acid. There's also a lot of solid products, formed by polymerization of acetone, but those were not volatile enough to be detected.
Update: corrected ion number for acetaldehyde. Now acetic acid is the only option for 45 m/z.

[Edited on 28-2-2018 by byko3y]


Dont try unsuccessful methods !.

[Edited on 7-2-2020 by Waffles SS]




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[*] posted on 7-2-2020 at 13:30


Waffles is right, I’m still not sure why we get so many people wanting to try stuff we know doesn’t work.

But nobody wants to work on the methods that do or might work. S2Cl2 is too hard, let’s build a ketene lamp. I don’t get it. Because ketene is safer than chlorine, somebody thinks.

I admit I’m just mad because I posted a kind of unlikely idea and everyone ignored me and then went for these obviously terrible ideas. Obviously I’m wasting my time




[Edited on 04-20-1969 by clearly_not_atara]
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[*] posted on 7-2-2020 at 15:28


Hope I don't sound hostile, but I read through the entire thread and determined the same. Someone mentioned an idea, and the same idea had been mentioned several times by others who had not read the full thread. I looked into it, found the idea to be futile and did not bother with saying so assuming anyone else who wanted to would do the same. It was simply an accessible idea, and even though I have no use for acetic anhydride I still found it worth looking into.
If you have an idea, test it yourself and report back. No one is stopping you.

[Edited on 2-8-20 by Abromination]




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[*] posted on 3-5-2020 at 11:03


I had an idea for forming acetic anhydride by transacylation with a more easily prepared cyclic anhydride. For example, maleic anhydride is freely soluble in aromatic solvents, whereas maleic acid is almost completely insoluble, on the order of tens of milligrams per liter of toluene. If there is any sort of equilibrium formation between maleic and acetic acids and anhydrides in toluene, the disproportionation would be driven forward by the extreme insolubility of maleic acid in the solvent.

To my dismay, according to Solvolytic Reactions of Cyclic Anhydrides in Anhydrous Acetic Acid (J. Pharm. Sci.), there is no appreciable equilibrium reaction between maleic or phthalic anhydrides and acetic acid. However, the equilibrium reactions between saturated cyclic anhydrides such as succinic anhydride, glutaric anhydride, and trans-1,2-cyclohexanedicarboxylic anhydride with acetic acid DO take place. But the solubility characteristics of those anhydrides in aromatic solvents are much less favorable! :mad:

From what little information I've found, succinic anhydride doesn't seem to be too soluble in aromatics, and the free acid is possible somewhat soluble as well. Glutaric anhydride/acid could perhaps be more favorable but I haven't found much in the way of solubility data. Perhaps if appropriate solvents could be found, the reaction could be made to work. Or perhaps in the case of maleic anhydride, a sufficiently long period of time could coax the sluggish equilibrium forward. It really seemed like I was on to something!
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[*] posted on 3-5-2020 at 11:29


Tamerlane: I had considered the same with Le Chatelier's principle applied through volatility:

RR=(C2O3) + HCl <> HO2CRRCOCl
HO2CRRCOCl + AcOH <> AcCl + HO2CRRCOCl

AcCl is much more volatile than any of the other rxn components and should distill out. In this case GAA is the ideal solvent.

However, while the preparation of succinic anhydride by thermolysis of succinic acid is commonly talked about, it is difficult to obtain a pure product in decent yield. I wonder if sodium pyrosulfate or metaphosphoric acid could be used to make succinic anhydride?

[Edited on 3-5-2020 by clearly_not_atara]




[Edited on 04-20-1969 by clearly_not_atara]
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