The liquid-phase oxidation of a naphthene-paraffin concentrate obtained from a mixture of Azerbaijan oils is studied in the presence of a nanostructured Mn-containing catalyst with a carbon basis. It is found that the catalyst system represents a dispersion medium containing catalyst particles with a hydrodynamic diameter of 0.5-1.3 A mu m. It is shown that the catalyst can be used for the production of carboxylic acids with yields as high as 42.9%.