2,6-Naphthalenedicarboxylic acid → 2,6-Dimethylnaphthalene

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Reaction Steps

Crystals of a crude 2,6-naphthalenedicarboxylic acid (the content of formylnaphthoic acid: 2,500 ppm; OD400: 1.5; the average particle diameter of the crystals: 5 μm) which was obtained by oxidation of 2,6-dimethylnaphthalene in the liquid phase in the presence of a Co/Mn/Br-based catalyst was mixed with water to prepare a slurry having a concentration of 20% by weight, and 300 g of the obtained slurry was placed into a 500 ml autoclave equipped with a stirrer under an atmosphere of nitrogen and heated at 280° C. Then, crystals of a crude 2,6-naphthalenedicarboxylic acid similar to the material used above was mixed with water to prepare a slurry having a concentration of 20% by weight, and the prepared slurry was supplied continuously into the autoclave at a rate of 120 g/hour at the room temperature. The residence time in the aging tank at 280° C. was kept at 3 hours, and a slurry was continuously taken out of the bottom portion of the autoclave at a rate of 120 g/hour. The crystals of 2,6-naphthalenedicarboxylic acid taken out of the bottom portion of the autoclave had an average particle diameter of 50 μm. The solubility of 2,6-naphthalenedicarboxylic acid in water at 280° C. is about 6 g in 100 g of water.

Provenance & Evidence