CATALYTIC COMPOSITION, METHOD OF ITS PREPARATION AND METHOD OF PURIFICATION OF TEREPHTHALIC ACID Russian patent published in 2000 - IPC

FIELD: chemical industry. SUBSTANCE: invention deals with catalytic compositions based on metals of group VIII of Periodic system for purification of terephthalic acid and methods of their preparation, and processes of purification of terephthalic acid suitable for subsequent synthesis of polyester polymers and copolymers used in production of textile fibers. Catalytic composition used for purification of terephthalic acid includes crystallites of catalytically active palladium and at least one metal of group VIII of elements of Periodic system applied to surface of carbon material in the form of mesoporous graphite material with mesopores sizing from 40 to 400 , and mesopore fraction in total volume of pores amounting to at least 0.5 and degree of graphite similarity of at least 20%. Metal crystallites in graphite material are distributed in volume of granules of carbon material so that maxima of distribution of active components are found at a distance from granule outer surface corresponding to 1-30% of granule radius. The method allows to produce selective and stable catalysts, and processes in which raw terephthalic acid with high initial content of n-carboxybenzaldehyde is selectively hydrogenated into n-toluic acid, and/or decarbonized into benzoic acid with low residual content of n-carboxybenzaldehyde. EFFECT: higher efficiency. 18 cl, 6 tbl, 39 ex