Peracid or peroxyacid

Alkenes are also oxidized to epoxides hy peracid or peroxyacid (RCO3H), e.g. peroxyhenzoic acid (C6H5CO3H). A peroxyacid contains an extra oxygen atom compared with carboxylic acid, and this extra oxygen is added to the double bond of an alkene to give an epoxide. For example, cyclohexene reacts with peroxyhenzoic acid to produce cyclohexane oxide. 

When a ketone is treated with a peracid (or peroxyacid), RCO3H, in the presence of an acid catalyst,... 

In the Baeyer-Villiger rearrangement, a ketone is treated with a peracid (or peroxyacid), in the presence of an acid catalyst, and the related ester of the ketone is produced by the equivalent of an insertion of an oxygen atom. If a cyclic ketone is treated in this manner, a lactone with a ring size one larger than the original ketone results. 

The Baeyer-Villiger process for conversion of open-chain ketones to esters, or cyclic ketones to lactones by a peracid involves an intermediate a-hydroxyperester (235) step, as shown in equation 83. Determination of 235 in the reaction mixture involves selective reduction of the peroxyacid with diphenyl sulfide and reduction of 235 with excess iodide, followed by titration of the liberated iodine. The presence of various transition metal ions may affect the determination by accelerating the final step of the synthetic process, thus... 

If the radical is electrophilic, the reaction does not occur at the 0—0 bond but, probably, there is addition onto the C = 0 or abstraction of the H of the peroxyacid group. The peracid is decomposed to the acid by a mechanism not well understead and which is still under investigation. 

Heat- and shock-sensitive peroxyacids (peracids) are formed when carboxylic acids react with hydrogen peroxide in the presence of methanesulfonic acid or sulfuric acid, or a strong acid cation-exchange resin ... 

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