Carboxylation of Formic Acid in Aqueous Solutions Under the Influence of U.V.‐LIGHT

Carboxylation of various organic substances by dissolved carbon dioxide or bicarbonate is achieved by the action of U.V. ‐Light of 184.9 and 253.1 mμ on water. The transformation of formic acid to oxalic acid was investigated in more detail as a function of u.v.‐dose, pH‐values and the formate concentration. For an irradiation period of 12 hr of 0.1 M formate, a yield of about 2 m mol.1‐‐1 oxalic acid was obtained. A reaction mechanism for the photochemical carboxylation process is presented. The results are of some interest in respect of the synthesis of organic compounds under the primitive earth conditions.