Peroxyacids from anhydrides

Dining an attempt to prepare an anhydrous 25% solution of peroxyacetic acid in acetic acid by dehydrating a water-containing solution with acetic anhydride, a violent explosion occurred. Mistakes in the operational procedure allowed heated evaporation to begin before the anhydride had been hydrolysed. Acetyl peroxide could have been formed from the anhydride and peroxyacid, and the latter may have detonated and/or catalysed violent hydrolysis of the anhydride [1], A technique for preparing the anhydrous acid in dichloromethane without acetyl peroxide formation has been described [2],... 

There is a strong single carbonyl band at 5.75 microns similar in shape and wave length to the carbonyl bands of aldehydes, ketones, peroxyacids, and esters, and different from the double carbonyl bands of acids, acid anhydrides, and diacyl peroxides. There is a neighboring, weaker band at 5.4 microns which might be considered a part of a double carbonyl band, but this seems doubtful because the two branches of a double carbonyl band are usually of approximately equal intensity and are usually closer together. The indications are that compound X from diacetyl is an acetyl compound—a logical product. 

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