Isomerization method of cyclohexane dicarboxylic acid

An isomerization method of cyclohexane dicarboxylic acid, comprising the step of isomerizing a cis isomer to a trans isomer by heat-treating a mixed solution which is prepared by mixing cyclohexane dicarboxylic acid comprising the cis isomer, water, and an isomerization catalyst,

• wherein the mixed solution comprises the cyclohexane dicarboxylic acid in an amount of 0.5% by weight to 30% by weight with respect to the total weight of the mixed solution, and
• the isomerization catalyst comprises one or more of oxide of a transition metal of Group 4, and is added in an amount such that a weight ratio of the isomerization catalyst to the cyclohexane dicarboxylic acid (a weight ratio of isomerization catalyst/cyclohexane dicarboxylic acid) of 0.1 or more.