STUDY OF THE KINETICS AND MECHANISM OF THE ACID-BASE CATALYZED ENOLIZATION OF HYDROXYACETALDEHYDE AND METHOXYACETALDEHYDE

Article abstract of DOI:10.1016/S0008-6215(00)85189-7

In acid and alkaline media, glycolaldehyde (hydroxyacetaldehyde) exists in equilibrium with its enediol form, which is quantitatively oxidized to glyoxal by an excess of Methylene Blue.In acid and alkaline media, the enol form of methoxyacetaldehyde is formed.In alkaline medium, this enol is stable; in acid, it undergoes hydrolysis to glycolaldehyde.The kinetics of enolization of glycolaldehyde and methoxyacetaldehyde were studied polarographically.The mechanisms of enolization of glycolaldehyde and acid hydrolysis of methoxyacetaldehyde were established both from kinetic data and from deuterium-incorporation data.The proposed mechanisms were confirmed by quantum-mechanical calculation of the charge distribution in the two compounds studied and their reaction intermediates.The glyoxal obtained in the oxidation was isolated as quinoxaline and analyzed by mass spectrometry.