Sciencemadness Discussion Board

Acetic anhydride

mbrown3391 - 20-6-2007 at 19:43

Im trying to synthesize acetic anhydride, and i read something on wikipedia about the condensation reaction of acetic acid forming it. Any idea what catylist would used for this? Also, any other methods of production would be appreciated. I know you can make it by the reaction of acetyl chloride and sodium acetate. Sodium acetate is obviously not a problem, but so far the only synths for acetyl chloride that ive read of involve hard to find chemicals like various phosphorous compounds and Thionyl chloride. Are there any more common chemicals that can be used to synthesize Acetyl chloride from acetic acid?

Ozone - 20-6-2007 at 20:29

No. So far as I know, acyl chlorides are impossible to make with "more common chemicals".

Please use the search engine, above and left, just under the Sciencemadness symbol. There is a ton of stuff on this subject.

alternatively, UTFSE.

Best,

O3

Sauron - 20-6-2007 at 22:19

There are threads on making acetic anhydride, and there are threads on making acetyl chloride and other lower acy chlorides notably propionyl chloride. Brother Ozone is correct that no additional thread is really required as even if someone comes up with something new it can be added to one or more of the existing threads profitably.

If you would like an encapsulation of the main conslusions I have come to on this subject feel free to PM me and I will expound.

mbrown3391 - 21-6-2007 at 12:18

Ive found two promising options-- the reaction of acetylene and acetic acid, and the reaction of acetaldehyde and sodium acetate. Any idea what catylists, if any, would be used in these reactions?

Eclectic - 21-6-2007 at 12:54

Google "acetylene acetic site:sciencemadness.org"

chemkid - 21-6-2007 at 13:18

On the organic chemistry section there is a thread

Sauron - 22-6-2007 at 02:02

The much more likely preparations are from acetyl chloride and anhydrous sodium acetate.

And there are two maybe three really reliable methods of [preparing the requisite acetyl chloride.

1. Benzoyl chloride and acetic acid per H.C.Brown in JACS, available on this site

2. TCT (cyanuric chloride) and acetic acid, by several methods all referenced from this site

3. Phthaloyl chloride and acetic acid. Article by Kyrides, JACS, available from this site. As phthaloyl chloride is more expensive than benzoyl chloride, this is a secondary choice, although you can equalize the cost somewhat by preparing the phthaloyl chloride from benzotrichloride and phthalic anhydride.

Note that either acetyl chloride or acetic anhydride itself can be prepared from oxalyl chloride, and oxalyl chloride can be made from oxalic acid and TCT.

I do not recommend thionyl chloride, nor any of the phosphorus halides for this purpose. I also do not recommend the ketene method as it is slow and extremely hazardous.

vulture - 22-6-2007 at 14:19

We have a HUGE thread on this. Don't be so fucking lazy.

Closed.