Process for the preparation of mono- or dicarboxylic acids from aldehydes, from their full acetals or hemiacetals or from mixtures thereof

The process as claimed in claim 2, wherein the aldehyde employed is an aliphatic or aromatic aldehyde having one or two aldehyde groups, hemiacetal or full acetal groups or mixtures thereof.

A process for the preparation of aliphatic or aromatic mono- or dicarboxylic acids of 4 to 22 carbon atoms by oxidation of the corresponding aldehydes having the same number of carbon atoms, which comprises carrying out the oxidation in a carboxylic acid from the group consisting of formic acid, acetic acid and propionic acid, or in a carboxylic acid/water mixture, at a temperature of 50.degree.-130.degree. C. and at from 1 to 25 bar in the presence of an oxidizing agent, wherein the oxidation is carried out in the absence of a catalyst.

A process for the preparation of aliphatic or aromatic mono- or dicarboxylic acids of 4 to 22 carbon atoms by oxidation of the corresponding aldehydes having the same number of carbon atoms, which comprises carrying out the oxidation in a carboxylic acid form the group consisting of formic acid, acetic acid and propionic acid, or in a carboxylic acid/water mixture, at a temperature of 50.degree.-130.degree. C. and at from 1 to 25 bar in the presence of an oxidizing agent, wherein the oxidation is carried out in the absence of a catalyst and an aprotic solvent.

A process for the preparation of aliphatic or aromatic mono- or dicarboxylic acids of 4-22 carbon atoms, which comprises reacting a chemical compound having at least one olefinic double bond with ozone in the presence of a solvent, catalytically hydrogenating the resulting peroxide solution, and then oxidizing the resulting aldehyde, after separating off the solvent and the catalyst, in the presence of a carboxylic acid from the group consisting of acetic acid, formic acid and propionic acid, or of a carboxylic acid/water mixture, at 50.degree.-130.degree. C. and 1-25 bar, in the presence of an oxidizing agent, to give the desired mono- or dicarboxylic acid, wherein the oxidation is carried out in the absence of a catalyst and an aprotic solvent.