PURPOSE: To prepare high purity title compound economically, in an industrial scale, with low solvent loss, by re-oxidizing a reaction slurry obtained by the liquid- phase oxidation of p-xylene, while keeping the concentration of p-toluic acid and the color strength of terephthalic acid within specific ranges.
CONSTITUTION: p-Xylene is oxidized in liquid phase in a single step reaction, with an oxygen-containing gas, pref. air, in the presence of a heavy metal catalyst such as Co and Mn, and a bromine compound such as bromine, hydrogen bromide, etc., in a lower aliphatic carboxylic acid such as acetic acid, propionic acid, etc. as a solvent. The redulting reaction mixture is re-oxidized in a re-oxidizing reactor, while keeping the concentration of p-toluic acid in the mother liquor within 300W 1200ppm, and the color strength of terephthalic acid in the slurry within 0.08W0.30. The high purity terephthalic acid thus obtained is useful as a raw material of fiber- grade polyester.
MURAKAMI KATSUYA
MIZUKAMI TETSUO
| JPS52108946A | 1977-09-12 | |||
| JPS51136640A | 1976-11-26 | |||
| JPS5016630A | 1975-02-21 |