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Author: Subject: Acetic anhydride preparation
clearly_not_atara
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[*] posted on 19-5-2021 at 15:11


^Considering I didn't say anything about using "salt" with muriatic, I'm not sure what you think you're critiquing.

In any case, this is tedious. If you have excess liters of sulfuric acid burning a hole in your pocket, obviously your problems are much different from mine. Hydrochloric acid is easily concentrated by distilling it over any number of dehydrating agents -- H3PO4, CaCl2, H2SO4, take your pick. I wish you luck in your efforts.

[Edited on 19-5-2021 by clearly_not_atara]




[Edited on 04-20-1969 by clearly_not_atara]
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[*] posted on 20-5-2021 at 00:45


Then it might be best to boil it under reflux (to get rid of water vapour), and led the HCl gas through a calcium chloride trap. This is slightly more complex than the sulphuric acid/salt generator, but has the definite advantage of not using any sulphuric acid.

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[*] posted on 28-7-2021 at 23:41


"Upon treating sodium acetate with chlorosulfonic acid in a little acetic
anhydride there is formed acetic anhydride". K.E. Jackson "Smoke-forming chemicals". The reference is PYTASZ AND RABEK:
Przemysl Chem. 14, 529-35 (1930).
(sorry if it was already mentioned - it is really hard to re-read the whole thread again)

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[*] posted on 6-3-2022 at 10:11


......it's a long thread , read 20 pages and didn't find any suggestion of doing a transterification of acetic acid with 4- toluene sulfonic acid in toluene using a dean stark trap to trap water. to acquire acetic anhydride ....I hava 4 toluene sulfonyl chloride and want to hydrolize it to attempt the procedure....no, no references only a theory...but would appreciate a method to hydrolyse th 4-toluene sulfonyl chloride to 4-toluene sulfonic acid.......solo



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[*] posted on 7-3-2022 at 13:16


Quote: Originally posted by solo  
......it's a long thread , read 20 pages and didn't find any suggestion of doing a transterification of acetic acid with 4- toluene sulfonic acid in toluene using a dean stark trap to trap water. to acquire acetic anhydride ....I hava 4 toluene sulfonyl chloride and want to hydrolize it to attempt the procedure....no, no references only a theory...but would appreciate a method to hydrolyse th 4-toluene sulfonyl chloride to 4-toluene sulfonic acid.......solo


There is no need for hydrolyzing Tosyl chloride(4-Toluenesulfonyl chloride),Just mix with dry Sodium acetate(1:2) and distill it !

The reaction is exothermic when started( 80-100c)

(Redistillation of product maybe needed if you want odorless and colorless Ac2O)


[Edited on 7-3-2022 by Waffles SS]




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[*] posted on 7-3-2022 at 18:09


Quote: Originally posted by Waffles SS  
Quote: Originally posted by solo  
......it's a long thread , read 20 pages and didn't find any suggestion of doing a transterification of acetic acid with 4- toluene sulfonic acid in toluene using a dean stark trap to trap water. to acquire acetic anhydride ....I hava 4 toluene sulfonyl chloride and want to hydrolize it to attempt the procedure....no, no references only a theory...but would appreciate a method to hydrolyse th 4-toluene sulfonyl chloride to 4-toluene sulfonic acid.......solo


There is no need for hydrolyzing Tosyl chloride(4-Toluenesulfonyl chloride),Just mix with dry Sodium acetate(1:2) and distill it !

The reaction is exothermic when started( 80-100c)

(Redistillation of product maybe needed if you want odorless and colorless Ac2O)


[Edited on 7-3-2022 by Waffles SS]


....thank you, what solvent would you use since tosyl chloride is insoluble in most solvents save benzene , ether and alcohol ( which might work for both tosyl chloride and sodium acetate.).....solo




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[*] posted on 8-3-2022 at 16:38


Sounds like waffles is describing a dry distillation to me.



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[*] posted on 9-3-2022 at 07:38


" Sounds like waffles is describing a dry distillation to me. "....you are right , that seems to be the case...thanks for pointing it out....solo



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[*] posted on 11-3-2022 at 01:12


Quote: Originally posted by solo  


....thank you, what solvent would you use since tosyl chloride is insoluble in most solvents save benzene , ether and alcohol ( which might work for both tosyl chloride and sodium acetate.).....solo


As swim said,I mean Dry distillation.(i did this method many times with Tosyl chloride and even Benzene sulfonyl chloride)

Try 2:1 and 3:1 ratio of sodium acetate : Aryl Sulfonyl chloride

[Edited on 11-3-2022 by Waffles SS]




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[*] posted on 15-4-2022 at 01:15


so much bickering about acetaldehyde but nothing in this 1000+post thread on the oxidation of acetaldehy into acetic anhydride?

as for the construction its rather easy of what ive been told
i know one person who produced liters of acetaldehyde which he then stored as some type of ammonia adduct in freezer
a regular glass jar with metal screw lid has a hole drilled in one side of the lid, air pumped through here
the middle a piece of copper, copper wire, spiral wound is left hanging in the "air" in the jar
ethanol is put in the jar
and an outlet composed of copper tube- my guess is that soldering wouldnt be required, silicone should do plenty well
it does get quite hot however
prior assembly the copper is heated up, the reaction is autocatalytic, it heats itself as the ethanol reacts with the CuO or Cu2O, then reduced back to copper, then oxygen in air delivered repeats the cycle
i recall something about silver or platinum being able to do the same with less heating- more desirable for making formaldehyde as that reaction tends to blow up more easily

the acetaldehyde is condensed in a container with icewater

since this whole thread mentioning acetaldehyde has only mentioned the construction of acetaldehyde generator, we never got to the actually interesting part, how do we go on from that to acetic anhydride? sodium persulfate? perchloric acid?




~25 drops = 1mL @dH2O viscocity - STP
Truth is ever growing - but without context theres barely any such.

https://en.wikipedia.org/wiki/Solubility_table
http://www.trimen.pl/witek/calculators/stezenia.html
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[*] posted on 15-4-2022 at 06:41


Well, for one thing, why would we choose a precursor (for Ac2O) which is a gas?

Acetaldehyde is a precursor to lots of interesting stuff, like 2-picoline, acetonitrile, glyoxal and chloral, but under most achievable conditions it will oxidize at the 2-position rather than the 1-position, which means that obtaining acetyl anything is going to be hard. Instead, acetaldehyde is interesting because it can be used to make other things.

Radical halogenation of acetaldehyde acetals should give acetals of acetyl halides. If the diol used can undergo a pinacol rearrangement, treatment with HBr@HOAc might give acetyl bromide and pinacolone; hopefully there are no further condensations. This seems unnecessarily laborious, though.




[Edited on 04-20-1969 by clearly_not_atara]
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[*] posted on 15-4-2022 at 09:00


.....cyanuric chloride will produce the acetic acid chloride , this with acetic acid will give you acetic anhydride.....Note:the article of cyanuric acid has been posted in the articles of interest in the Reference section.........solo



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[*] posted on 16-4-2022 at 06:02


i think i figured out why acetaldehyde has even been mentioned in the first place
it has been confused from acetone-glacial acetic acid reaction where acetone is reacted at high temperature to form ketene- which is a gas, a highly deadly gas, this gas however is bubbled into glacial acetic acid in a totally closed apparatus where it then causes it to turn into acetic anhydride

as i see it, it would be best to have 3 glacial acetic acid traps for the ketene gas as well as ventilation.. ketene may be reacted easily with ammonia gas just as a 100% scrubbing mechanism maybe?

video from dougs lab he explains hydrogen cyanide is dangerous in 50ppm where ketene is 5ppm or even less

so it was never about acetaldehyde, it does use a "ketene lamp" kinda construction, which acetaldehyde also does use, but very different setup!

the ketene in glacial acetic acid is decently attractive, but if one can just wetten anhydrous sodium acetate with glacial acetic acid, and distill that, that would be a lot safer- i didnt quite see anything on temperature of this distillation, i would expect it to be decently high? sodium acetate starts to decompose just over 150*C- so drying out NaAc has to be at most 150*C




~25 drops = 1mL @dH2O viscocity - STP
Truth is ever growing - but without context theres barely any such.

https://en.wikipedia.org/wiki/Solubility_table
http://www.trimen.pl/witek/calculators/stezenia.html
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[*] posted on 27-4-2022 at 13:40


Acetaldehyde with tert-butyl hypochlorite should create acetyl chloride:
"tert-Butyl hypochlorite is a versatile and inexpensive oxidizing agent, that allows the conversion of alcohols to ketones, aldehydes to acid chlorides, sulfides to sulfoxides, and hydroxylamines to nitroso compounds"
-https://www.organic-chemistry.org/chemicals/oxidations/tert-butyl-hypochlorite.shtm#:~:text=tert-Butyl%20hypochlorite%20is%20a,and%20hydroxylamines%2 0to%20nitroso%20compounds.




There wasn't a fire, we just had an uncontrolled rapid oxidation event at the power plant.
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[*] posted on 28-4-2022 at 06:49


Lots of interesting transformations are possible with tBuOCl. It turns amines to N-chloroimines, aldehydes with sodium azide to acyl azides, allylic carbons to allyl halides, incautious chemists to smoldering piles of ash, etc.



[Edited on 04-20-1969 by clearly_not_atara]
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[*] posted on 29-4-2022 at 08:03


Well, there is this really annoying chemist who works 3 hoods away from me at work :P



There wasn't a fire, we just had an uncontrolled rapid oxidation event at the power plant.
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[*] posted on 17-5-2022 at 19:29


In the "acetonitrile method", is it really necessary to gas HCl? Couldn't you get a similar effect by adding an AcOH solution of H2SO4 or TsOH to a solution of NaCl in AcOH/MeCN? Sodium chloride appears to be somewhat soluble in AcOH, and hopefully MeCN will not crash it out:
https://pubs.acs.org/doi/pdf/10.1021/ja01276a009




[Edited on 04-20-1969 by clearly_not_atara]
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[*] posted on 19-5-2022 at 12:22


Quote: Originally posted by clearly_not_atara  
In the "acetonitrile method", is it really necessary to gas HCl? Couldn't you get a similar effect by adding an AcOH solution of H2SO4 or TsOH to a solution of NaCl in AcOH/MeCN? Sodium chloride appears to be somewhat soluble in AcOH, and hopefully MeCN will not crash it out:
https://pubs.acs.org/doi/pdf/10.1021/ja01276a009


Maybe this be unclear for this reaction but i had success on synthesis Methyl Phenyl Butenone(Not for P2P) by AcOH solution of H2SO4 in aldol condensation of BzH and MEK instead of gassing HCl.

I think your idea is worth trying just as much as my idea.



[Edited on 19-5-2022 by Waffles SS]




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[*] posted on 4-6-2022 at 11:20


https://patents.google.com/patent/US3513180

"A mixture of 60 g. of benzoic acid and 0.5 g. of trimellitic anhydride in a 250 ml. flask was heated to reflux for 6 hours. Water vapor (about 2 ml.) produced by the dehydration reaction was condensed in a Dean-Stark trap. The product consisted of a mixture of benzoic acid and benzoic anhydride."

If Bz2O reacts with NaOAc without a proton donor, I think Ac2O is the most volatile possible product. Benzoic acid is about three times as strong as acetic acid.




[Edited on 04-20-1969 by clearly_not_atara]
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[*] posted on 4-6-2022 at 23:58


Quote: Originally posted by clearly_not_atara  
https://patents.google.com/patent/US3513180

"A mixture of 60 g. of benzoic acid and 0.5 g. of trimellitic anhydride in a 250 ml. flask was heated to reflux for 6 hours. Water vapor (about 2 ml.) produced by the dehydration reaction was condensed in a Dean-Stark trap. The product consisted of a mixture of benzoic acid and benzoic anhydride."

If Bz2O reacts with NaOAc without a proton donor, I think Ac2O is the most volatile possible product. Benzoic acid is about three times as strong as acetic acid.


As patent mentioned there is no need for NaOAc and Ac2O produced directly from Catalyst and Acetic acid.(I hope this route works because i was unsuccessful in Phthalic anhydride + acetic acid)


Quote:

It has now been found that this objective may be accomplished by carrying out the dehydration reaction in the presence of a small amount of a 1,2-dicarboxylic acid or the corresponding anhydride which acts to catalyze the dehydration of the monocarboxylic acids.

Monocarboxylic acids that may be dehydrated by the process of the invention include saturated and unsaturated aliphatic, alicyclic, aromatic and heterocyclic acids having from about 2 to 18 carbons, as well as derivatives of these acids. Examples are acetic, propionic, caprylic, lauric, stearic, crotonic, oleic, linoleic, cyclopropanecarboxylic, cyclohexanecarboxylic, cyclohexenecarboxylic, cyclodecanecarboxylic, benzoic, toluic, phenylacetic, cinnamic, 1-naphthylacetic, nicotinic and benzofuroic acids.




[Edited on 5-6-2022 by Waffles SS]




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[*] posted on 5-6-2022 at 05:06


You are correct, the patent method can work directly with AcOH. But that doesn't lower the reaction temperature of 230-260 C, meaning that you need a pressurized setup. I thought it would be more practical to use benzoic acid at atmospheric pressure for most members.



[Edited on 04-20-1969 by clearly_not_atara]
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[*] posted on 5-6-2022 at 11:28


Quote: Originally posted by clearly_not_atara  
You are correct, the patent method can work directly with AcOH. But that doesn't lower the reaction temperature of 230-260 C, meaning that you need a pressurized setup. I thought it would be more practical to use benzoic acid at atmospheric pressure for most members.


Thats true.
Monocarboxylic acids with a boiling point of less than 230 degrees do not lead to the formation of anhydride at atmospheric pressure,because below this temperature, mentioned dicarboxylic acid(Phthalic acid) will not lose water and make anhydride itself.

The mechanism of this reaction is interesting for me.
I think each mole of Dicarboxylic acid react with two mole of Monocarboxylic acid and make 1 mole Asymmetric Dicarboxylic anhydride and above 230c 5 members Dicarboxylic anhydride regenerate and lead to formation of carboxylic anhydride.


Untitled-1.jpg - 40kB

[Edited on 5-6-2022 by Waffles SS]




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[*] posted on 15-6-2022 at 11:23


The preferred catalyst in the patent is trimellitic acid, which is not exactly something everyone has. But I'm pretty sure that it could easily be produced by the action of permanganate on naproxen, which is 2-(6-methoxy-naphth-2-yl)-propanoic acid. Naproxen is also known as Aleve:

That permanganate reacts with naproxen is documented in this M.S. thesis:
https://smartech.gatech.edu/bitstream/handle/1853/33870/gibs...
but the products are not identified. However, it is known that phthalic acid is produced by the action of permanganate on naphthalene:
https://researchgate.net/profile/Bijudas-K/publication/31211...
so it is a natural extension to infer that trimellitic acid is produced by oxidation of the naproxen ring and alkyl chain. Permanganate is also known to oxidize phenylacetic acid:
https://research.monash.edu/en/publications/heterogeneous-pe...

So this catalyst might be very easy to get after all. And the method should scale nicely.




[Edited on 04-20-1969 by clearly_not_atara]
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