Oxidation of acetaldehyde to glyoxal by nitric acid

The liquid phase oxidation of acetaldehyde or paraldehyde by aqueous nitric acid to glyoxal was investigated in a stainless steel autoclave maintained under autogenous pressure. The presence of nitrous acid was necessary for the reaction. Acetic acid and glyoxalic acid were the major by-products. The effects of concentration of nitric acid, nitrous acid and acetaldehyde as well as temperature and period of reaction on the conversion and yield of glyoxal were studied with a view to obtaining the most suitable conditions for the production of glyoxal.