Abstract: The present invention relates to a method for refining 2,6-naphthalene dicarboxylic acid, and particularly to a method for refining 2,6-naphthalene dicarboxylic acid comprising recrystallizing crude 2,6-naphthalene dicarboxylic acid in the form of an amine salt using a solvent comprising a protic polar solvent selected from the group consisting of an alcohol, water, and a mixture thereof, and an acetate. In accordance with the invention, 2,6-naphthalene dicarboxylic acid can be obtained with excellent purity and color, and at the same time, it can be obtained in an economical and environmentally friendly way because the acetate, which is a byproduct of the oxidation process, is used as a solvent.

Abstract: The present invention relates to a method for refining 2,6-naphthalene dicarboxylic acid, and particularly to a method for refining 2,6-naphthalene dicarboxylic acid comprising recrystallizing crude 2,6-naphthalene dicarboxylic acid in the form of an amine salt using a solvent comprising a protic polar solvent selected from the group consisting of an alcohol, water, and a mixture thereof, and an acetate. In accordance with the invention, 2,6-naphthalene dicarboxylic acid can be obtained with excellent purity and color, and at the same time, it can be obtained in an economical and environmentally friendly way because the acetate, which is a byproduct of the oxidation process, is used as a solvent.

Abstract: Disclosed is a method of producing trimellitic acid through the liquid-phase oxidation of pseudocumene in acetic acid. The oxidation comprises a) conducting a first oxidation using an initial oxidizing catalytic system at 120-200iÉ for 5-20 min in an oxidizing reactor, said initial oxidizing catalytic system comprising at least three compounds selected from the group consisting of cobalt compound, manganese compound, zirconium compound and bromine compound; b) conducting a second oxidation in situ at 160-220iÉ for 30-60 min under addition of an additional catalytic system, said additional catalytic system comprising at least two compounds selected from the group consisting of cobalt compound, manganese compound, zirconium compound, and bromine compound; and c) completing the oxidation of pseudocumene at a temperature from 180 to 230iÉ for a time from 5 to 20 min without the addition of catalysts into the reactor. The pressure is adjusted in the range from 100 to 450 psig over the steps a), b) and c).