| 摘要 |
PURPOSE:p-Xylene is oxidized in liquid phase in the presence of a reaction promotor, etc. to give slurry which is heated to separate terephthalic acid where the mother liquor is oxidized and subsequently recycled to the oxidation process to increase the purity of the terephthalic acid. CONSTITUTION:p-Xylene is oxidized in liquid phase with O2-containing gas in acetic acid at 110-140 deg.C in the presence of a catalyst, e.g. Co compound, and a reaction promotor, e.g. paraldehyde, acetaldehyde, etc. Maintaining the temperature higher than the reaction temperature by 5 deg.C, terephthalic acid is separated from the obtained oxidized slurry. In this process, the residual mother liquor obtained after the separation of terephthalic acid is oxidized with O2-containing gas in the presence of the reaction promotor to transform the harmful substance to the substance which does not decrease the quality of terephthalic acid. The substance obtained is recycled to give high quality terephthalic acid conveniently in an industrial scale. |
