| 摘要 |
PURPOSE:In producing the titled substance by subjecting paraxylene to the first oxidation reaction in the presence of a catalyst containing a heavy metal and bromine, subjecting the reaction mixture to the second oxidation at a temperature lower than the reaction, subjecting it to the third oxidation at a higher temperature to add the heavy metal and bromine at a stage after the second oxidation. CONSTITUTION:In producing high-purity terephthalic acid by oxidizing paraxylene with oxygen in the presence of a catalyst (e.g., Co-Mn-Br system) containing a heavy metal and bromine at 180-230 deg.C so that >=95wt% paraxylene is converted into terephthalic acid (the first oxidation reaction), subjecting the reaction mixture to the second oxidation with oxygen at a temperature 2-30 deg.C lower than the first reaction, subjecting it to the third oxidation again at a temperature higher than the first oxidation reaction (preferably at 235-290 deg.C), 0.1-1 as much heavy metal and bromine as the heavy metal and bromine used in the first oxidation reaction is added to the reaction mixture during a period from the end of the first oxidation reaction to the third oxidation (especially a period before the second oxidation). |
