PROCESS FOR PRODUCING HIGH-PURITY TEREPHTHALIC ACID

WIPO Patent Application WO/2005/115956

A1

A process for producing high-purity terephthalic acid which comprises: an oxidation step (a) in which p-xylene is oxidized to obtain crude terephthalic acid; a dissolution step (b) in which the crude terephthalic acid is dissolved in a water solvent to obtain an aqueous solution of the crude terephthalic acid; a reduction step (c) in which the aqueous solution of the crude terephthalic acid is brought into contact with hydrogen to obtain a liquid resulting from a reduction reaction; a crystallization step (d) in which the liquid resulting from a reduction reaction is cooled to crystallize high-purity terephthalic acid; a solid-liquid separation step (e) in which the slurry obtained in the crystallization step (d) is subjected to solid-liquid separation; and a crystallization step (f) in which the isolated mother liquor obtained in the solid-liquid separation step (e) is cooled to form crystals consisting mainly of the terephthalic acid and p-toluic acid contained in the mother liquor, wherein the cooling of the mother liquor is conducted using two or more cooling tanks which have a reduced pressure so as to vaporize the water solvent contained in the mother liquor and in which the last cooling tank is regulated so as to have a pressure below the atmospheric pressure and a temperature of 40-70°C.

FUKUI KATSUHIKO (JP)
NUMATA MOTOKI (JP)

PCT/JP2005/009461

December 08, 2005

May 24, 2005

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MITSUBISHI CHEM CORP (JP)
FUKUI KATSUHIKO (JP)
NUMATA MOTOKI (JP)

C07C51/43; C07C63/26; (IPC1-7): C07C51/43; C07C63/26

WO2002028499A1

2002-04-11

JPH07507291A	1995-08-10
JPH11228492A	1999-08-24

Oguri, Shohei (7-13 Nishi-Shimbashi 1-chom, Minato-ku Tokyo 03, JP)

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