| abstract |
(57) [Summary] [Objective] A method for producing high-purity terephthalic acid from a slurry solution of terephthalic acid crystal slurry after catalytic hydrogenation of crude terephthalic acid obtained by liquid phase oxidation. [Structure] Liquid phase oxidation of p-xylene and the like was performed in an acetic acid solution in the presence of a cobalt and manganese catalyst and a bromide compound for 10 times. -30 atm, 150-240 ° C or in the presence of cobalt catalyst, in acetic acid solution, 5-20 atm, 100-170 ° C. And the resulting crude terephthalic acid is subjected to catalytic hydrogenation in high temperature water of 200 ° C. or higher in the presence of a Group 8 noble metal catalyst. After removing the catalyst, the pressure was lowered and the temperature was lowered to form a terephthalic acid crystal slurry solution, the temperature of which was adjusted to 120 to 200 ° C., and the solution was introduced into the solvent displacement tower. The terephthalic acid crystals are separated from the top of the tower, and the terephthalic acid crystals are taken out as a slurry solution together with high temperature water from the bottom of the tower, and the terephthalic acid crystals are separated from the latter slurry solution. |