| 摘要 |
PURPOSE:To obtain the titled substance of high whiteness, by oxidizing p-xylene with molecular oxygen in the liquid phase in a certain limited temperature range while feeding the oxygen to a reactor to keep the O2 concentration in a waste gas discharged from the reactor in a specific range. CONSTITUTION:p-Xylene is oxidized with a gas containing molecular oxygen, e.g. air, in the liquid phase in the presence of a Co-Mn-Br catalyst the give terephthalic acid. In the process, the reaction temperature is kept at 170-195 deg.C, preferably 170-189 deg.C, and the unreacted oxygen is fed into the reactor to give the unreacted oxygen in the noncondensible gas discharged from a reactor is 6.2-12vol% and in the range of 6.2+0.35(182-t)-6.2+0.6(198-t)vol% (t is the reaction temperature) to carry out the reaction. In this case, the concentration of metallic Co based on the solvent, preferably acetic acid, is 0.05-0.5wt%, and the amounts of the Mn and Co compounds are as follows: 0.1-20wt% expressed in terms of metallic Mn based on metallic Co. |
