PURIFICATION OF GLYOXYLIC ACID

摘要

PROBLEM TO BE SOLVED: To provide a purification method enabling high purity glyoxylic acid hardly containing glyoxal to be obtained. SOLUTION: When obtaining glyoxylic acid by purifying a reaction product liquid containing glyoxylic acid obtained by oxidation of glyoxal with nitric acid, this method is to convert glyoxylic acid in the reaction product liquid into a hemiacetal ester with alcohol and then to distill a distillate of a glyoxylic acid hemiacetal ester-alcohol-water out of the system, followed by adding water to the distillate to hydrolyze the glyoxylic acid hemiacetal ester into glyoxylic acid.