METHOD FOR PRODUCING OXALIC ACID

PROBLEM TO BE SOLVED: To provide a method for producing oxalic acid, capable of mass-producing oxalic acid in high yield, while excellent in stability and certainty of treatment, initial cost, running cost and the like, by a simplified and facilitated steps and production equipment, thereby attaining much price cutting of oxalic acid.SOLUTION: In the production method, an aromatic compound such as phenol dissolved in an aqueous solution is made to trace the following processes to synthesize the oxalic acid. In the first process, the presence or absence of a hydroxy group is determined, and, when present, an OH radical takes a hydrogen atom in a hydroxy group to oxidize, and returns itself to water and makes an oxygen atom to have a double bond. In the second process, the presence or absence of a hydrogen atom attached to a carbon atom is determined, and, when present, an OH radical takes a hydrogen atom to oxidize, and returns itself to water. In the third process, an OH radical is added to the unpaired electron of a carbon atom to produce a hydroxy group. Further in the fourth process, a polarized carbonyl group is reduced with a nascent state hydrogen.