Technique for synthesizing oxalic acid from oxalate

The invention relates to a technique for synthesizing oxalic acid from oxalate, which comprises the following steps: preheating liquid-form oxalate and water, and sending into a hydrolysis reaction tower to perform hydrolysis reaction; and in the hydrolysis reaction process, separating the generated oxalic acid from the oxalate and alcohol through reaction rectification, wherein the alcohol is recovered from the tower top, and the oxalic acid is recovered from the tower bottom. The reaction rectification process is utilized to separate the alcohol generated in the oxalate hydrolysis process from the oxalic acid and water, thereby accelerating the oxalate hydrolysis and enhancing the yield and product purity of the oxalate. The generated oxalic acid quality satisfies the requirements for superior goods in Chinese Standard GB/T1626-2008. The technique can implement industrial production and enhance the oxalic acid yield on the premise of overcoming the defects in the prior art, and no waste liquid is discharged in the whole production process.