| 摘要 |
A method for preparing highly pure crude terephthalic acid is provided to minimize the loss of acetic acid resulting from an oxidation step, inhibit the formation of organic impurities, and produce a good quality of crude terephthalic acid. The method for preparing highly pure crude terephthalic acid comprises the steps of: liquid-oxidizing para-xylene with oxygen or oxygen-containing gas at 150-200°C in a pressure range of 7-20kg/cm^2 to collect crude terephthalic acid slurry; subjecting the slurry to solid-liquid separation; re-slurrying the crude terephthalic acid; and washing the slurry, and then subjecting the washed slurry to solid-liquid separation. A mixed solvent obtained by mixing 98.8-99.9wt% of acetic acid and 0.1-1.2wt% of methyl acetate is used as a solvent. A catalyst system containing cobalt, manganese, bromine, and copper is used as a catalyst system.
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