METHOD OF PRODUCING HIGHLY PURE TEREPHTHALIC ACID Russian patent published in 2010 - IPC C07C51/235 C07C51/265 C07C63/26 

FIELD: chemistry.

SUBSTANCE: terephthalic acid production method involves a step A) for oxidising paraxylene to terephthalic acid with air in the presence of a liquid reaction phase kept at temperature between 180°C and 230°C, where the liquid reaction phase contains paraxylene, acetic acid, water and a catalyst composition, where amount of water is 5-12% of the weight of acetic acid, the mass ratio of acetic acid to paraxylene is not less than 30:1 and must be such that 15-50% of reacted terephthalic acid is present in solid form at oxidation temperature and the catalyst composition contains cobalt, manganese and bromine combined with at least one element selected from a group consisting of zirconium and hafnium, where atomic ratio Co:Mn:Br is in the range 1:0.2-1.0:1.1-2.7, and atomic ratio of cobalt to elements selected from a group consisting of zirconium and hafnium is equal to 1:0.03:0.3, where total mass of Co and Mn is equal to 100-500 mg per 1 kg of the liquid reaction phase; and B) extraction of terephthalic acid through crystallisation at temperature between 150°C and 80°C.

EFFECT: method gives terephthalic high purity without a secondary purification step currently used in practice.

3 cl, 19 ex, 3 tbl