Author Topic: Acetic Anhydride: alternative preparation  (Read 4237 times)

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Acetic Anhydride: alternative preparation
« on: June 28, 2004, 06:28:00 PM »
[patent] uk128282

Tells us of a novel preparation of anhydrides using in the free state, Phoshourous and Chlorine,.

6.CH3CooNa+P+3Cl---=> 3(CH3CO)2O+Na3PO3+3NaCl

Conventionally a compound conataining P & Cl(Ie Pcl3) have been documented in the preparation of the anhydride from the corresponding salt.
Seems, though, the elemental forms will do the job as well.

Hopefully this is of some interest to all, who have this chemical as a stumbling block in sysnthesis of greater compounds,.

The paper mentions not only the use of Red p, but other, allotropic forms?, can be used,.

Chlorine gas is pumped into a intimate mix of Phosphorous and the sodium salt of Acetic acid.A ratio of~ 1:30 (P:Na-acetate) is used to form the anhydride, and the amount of chlorine being the determining factor to then yield Acetyl chloride,)

Maybee this anolologeous application of just enough chlorine, could be a way how to solve the over oxidising of acetaldehyde, in the bleach + etoh effort,.ie, by just adding enough of the oxidiser, as to not catalyse the production of unwanted chlorination of the aldehyde.

Just a thought

Ambi ;)