| 摘要 |
PROBLEM TO BE SOLVED: To produce 2,6-naphthalenedicarboxylic acid dimethyl (2,6-NDCM) at a low cost on an industrial scale by efficiently removing, with a simple process, impurities contained in the reaction product of the esterification of 2,6-NDCA, which is obtained by liquid phase oxidation of dialkylnaphthalene, with methanol to obtain high purity 2,6-NDCM and recovering the metal of the oxidation catalyst. SOLUTION: 2,6-Dialkylnaphthalene is oxidized in the presence of a catalyst composed of a heavy metal compound and a bromine compound in a solvent containing a lower aliphatic carboxylic acid using a molecular oxygen-containing gas to produce 2,6-NDCA. The 2,6-NDCA is esterified with methanol, and the obtained crude ester is purified by recrystallization and distillation. In this process for producing the high purity 2,6-NDCM, an aromatic hydrocarbon is used as a solvent for separating insoluble materials in the crude ester and recrystallization. |
