Peroxy acid

As peroxy carboxylic acids - also called peracids - referred to a representative of a group of substances of organic compounds that contain a peroxycarboxyl ( Peroxycarbonsäurengruppe ) as a functional group. All peroxy carboxylic acids containing a free hydroperoxide ( HOO - group) and can therefore be regarded as acyl hydroperoxides. Like most peroxides, peroxy carboxylic acids in the pure or highly concentrated form are explosive. With increasing chain length the explosion potential decreases. Short-chain aliphatic peroxy carboxylic acids are soluble in water up to ~ C6, then outweighs the water-insoluble ( lipophilic ) portion of the molecule. Aromatic peroxy carboxylic acids are more soluble in water than in organic solvents.

Production

Peroxycarboxylic acids can be prepared from carboxylic acids and hydrogen peroxide ( equation 2 by back-reaction ) reactions. Especially aromatic peroxy carboxylic acids are prepared from carboxylic acid chlorides and hydrogen peroxide in a basic medium.

Peroxy carboxylic acids are also formed by autoxidation of aldehydes.

Reactions

Peroxycarboxylic acids are generally unstable and, therefore, prepared in the synthesis only during the reaction of the carboxylic acid and hydrogen peroxide ( in situ). An exception is the meta -chloroperbenzoic acid, which is crystalline and stable.

Peroxy carboxylic acids and alkenes can react at room temperature to give epoxides ( Prileschajew reaction). Next the epoxide is produced a carboxylic acid. Frequently as peroxy carboxylic acid meta- chloroperbenzoic acid ( MCPBA ) is used. Other percarboxylic acids, which can be used for epoxidation are peroxyformic acid and peroxyacetic acid.

Peroxycarboxylic acids are used as the oxidizing agent, for example, the Baeyer-Villiger oxidations.

Peroxy carboxylic acids are weak acids and leave as one such acid -base reactions. Their salts can be used for purification and isolation.