| 摘要 |
PURPOSE:To prepare terephthalic acid for direct polymerizaton, by the liquid phase oxidaton of p-xylene in an acetic acid solvent containing specific concentration of water, in the presence o specific amounts of Co, Mn, and a Br compound, thereby suppressing the decomposition of the acetic acid solvent. CONSTITUTION:Terephthalic acid is prepared by the oxidation of p-xylene with oxygen-containing gas in an acetic acid solvent, in the presence of a catalyst comprising heavy metal compounds and a bromine compound, under the following conditions: The concentration of water in the solvent at the oxidaton reaction zone is maintained between 14 and 16wt%; a Co compound and a Mn compound are used as the heavy metal compounds; the amount of Co is >= 200 wt ppm of the solvent; the ratio of Mn to Co is 0.2-300 to 100; the sum of Co and Mn is <= 2000 ppm of the solvent; and when the sum of Co and Mn is >= 850 ppm, the reaction temp. is 185-210 deg.C; and when it is < 850 ppm, the temperature is kept between 180 and 200 deg.C. |
