Identification of organic compounds : LXXXIX. Paper and thin-layer chromatography of monohydric phenols as antipyrylquinoneimine dyes

Abstract

The conversion of phenols into coloured derivatives using the reaction with 4-aminoantipyrine and an oxidizing agent has been described. p-Unsubstituted phenols or phenols substituted with halogeno, carboxy or sulpho groups in the p-position react to form red antipyrylquinoneimines. Phenols with p-alkoxy groups react only partially. p-Alkylphenols give yellow products under the same conditions. The red dyes are most effectively separated using the partition system formamide/ n-hexane—benzene (1:1) on paper or thin layers of cellulose, whereas the solvent system dimethylformamide/ n-hexane is suitable for the yellow products. The separation of isomeric m- and p-alkylphenols is carried out on Silufol sheets using benzene—acetone (3:1) as the mobile phase. The separation of m- and p-halogenophenols is achieved by the elimination of the halogen in p-position. The yellow products are relatively less stable both in solution and on chromatograms, and therefore the coloured derivatives should be freshly prepared.