METHOD FOR PRODUCING HIGH-PURITY TEREPHTHALIC ACID

Title:

METHOD FOR PRODUCING HIGH-PURITY TEREPHTHALIC ACID

Document Type and Number:

WIPO Patent Application WO/2018/051775

Kind Code:

A1

Abstract:

Provided is a method for producing high-purity terephthalic acid, said method including the following steps (a) through (e): (a) a step for liquid-phase oxidizing a p-phenylene compound to obtain crude terephthalic acid crystals; (b) a step for dissolving the crude terephthalic acid crystals in water, followed by performing a catalytic hydrogenation treatment; (c) a step for using at least two stages of crystallization tanks to gradually decrease the pressure and temperature of the catalytically hydrogenated reaction liquid, crystallize the terephthalic acid, and obtain a terephthalic acid slurry; (d) a step for introducing the terephthalic acid slurry into the top of a mother liquor substitution column, bringing the slurry into contact with a rising stream of substitution water introduced from the bottom of the mother liquor replacement column as terephthalic acid crystals are precipitated within the column, and removing the terephthalic acid crystals from the bottom of the column in the form of a slurry with the substitution water; and (e) a step for solid-liquid separating the slurry removed from the bottom of the column into water and terephthalic acid crystals, and drying the separated terephthalic acid crystals; wherein when the quantity of crystals subjected to the catalytic hydrogenation treatment is designated as Q (ton/hr), the residence time within the first of the at least two stages of crystallization tanks is designated as T1 (hr), and the cross-sectional area of the mother liquor substitution column is designated as A[m2], the following conditions (1) through (3) are met: (1) 0.07 ≦ T1 ≦ 0.5; (2) 0.3 ≦ A/Q ≦ 0.8; (3) 0.035 ≦ T1 × A/Q ≦ 0.25. Such a method for producing high-purity terephthalic acid allows for efficient mother liquor substitution, has a low heating load when drying the purified terephthalic acid cake following solid-liquid separation, and is capable of producing terephthalic acid that exhibits good behavior as a feedstock material for polyester.

Inventors:

NAKAMURA GOH (JP)
FUJITA HIDEAKI (JP)
MURAKAMI KOTARO (JP)
SHIGEMATSU RYUSUKE (JP)

Application Number:

PCT/JP2017/030795

Publication Date:

March 22, 2018

Filing Date:

August 28, 2017

Export Citation:

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Assignee:

MITSUBISHI GAS CHEMICAL CO (JP)

International Classes:

C07C51/47; C07C63/26

Foreign References:

JP2002522406A	2002-07-23
JP2014524928A	2014-09-25
JPH07291896A	1995-11-07
JPH10195016A	1998-07-28
JPH11228492A	1999-08-24
JP2006096710A	2006-04-13

Other References: