PRODUCTION OF ALKYL ESTER OF OXALIC ACID

摘要

PROBLEM TO BE SOLVED: To provide an industrial production method of an alkyl ester of oxalic acid by which the heat of reaction in the regeneration of RONO is effectively removed to maintain the reaction temperature within a proper range and various problems of a conventional production method can be avoided in the production method by reacting CO with the RONO to provide an alkyl oxalate, regenerating the RONO from the by-produced nitrogen oxide and reusing the RONO. SOLUTION: This production method of an alkyl ester of oxalic acid comprises a first step for reacting CO with RONO to provide an alkyl oxalate, a step for bringing the reaction gas into contact with an absorbing liquid to condense and dissolve the alkyl oxalate, taking out the condensed liquid containing the condensed and dissolved alkyl oxalate and simultaneously taking out the uncondensed gas, a third step for supplying the uncondensed gas to a regenerating column and reacting nitrogen oxide with an alcohol to provide the RONO, and a fourth step for distilling and purifying the condensed liquid to provide the alkyl oxalate. A recycling amount of a bottom liquid of a regenerating column, a molar ratio of the total supplying amount of the alcohol to the nitrogen oxide, and an alcohol concentration in the bottom liquid are maintained within specific values to provide the RONO and the obtained RONO is reused at the first step.