| 摘要 |
PURPOSE:To prepare high purity terephthalic acid useful as a raw material of polyester fiber, continuously, in high yield, by contacting slurry containing crude terephthalic acid obtained by the oxidation of p-tolualdehyde in the presence of Br<->, with hot water. CONSTITUTION:Slurry containing crude terephthalic acid obtained by the oxidation of p-tolualdehyde with an O2-containing gas in the presence of Br<-> in water, is introduced into the ascending stream of hot water at 180-310 deg.C. The mother liquor flows upward accompanied by the ascending flow of the hot water, and the crystals of terephthalic acid is precipitated in the hot water, extracted together with a part of the hot water from the reactor, and separated from the reaction solvent to obtain the objective high purity terephthalic acid. The separation of the cystal and the reaction solvent is carried out in a column separator, e.g. the one having baffle plates, wherein the ascending stream of the hot water is not so high as to cause the back-mixing of the components. |
