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Process for producing high purity terephthalic acid

A terephthalic acid, high-purity technology, applied in the field of preparation of high-purity terephthalic acid, can solve the problems of activity reduction, reduction catalyst poisoning, etc.

Inactive Publication Date: 2007-06-20
MITSUBISHI CHEM CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Carbon monoxide is a catalyst poison of the reduction catalyst used in this reduction step, as a result, the reduction catalyst is poisoned and its activity is reduced

Method used

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  • Process for producing high purity terephthalic acid

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Embodiment 1

[0030] This embodiment is accomplished by using the process shown in FIG. 1 . Specifically, in the mixing tank 11, crude terephthalic acid containing 3,000 ppm of 4CBA and water were charged at 18 tons / hour to prepare a slurry C of 30% by weight of crude terephthalic acid. Pressurize the slurry C to a pressure of 8.9MPa, raise the temperature to 285°C through a multi-tubular heat exchanger 12 to dissolve terephthalic acid, and then inject the aqueous solution D of terephthalic acid into the hydrogenation reactor 13 middle. The hydrogenation reactor 13 had a column diameter of 1,260 mm and a height of 10 m, and 0.5% by weight of palladium attached to activated carbon was used as a reduction catalyst, and the amount of the catalyst charged was 6 tons. In this hydrogenation reactor 13, hydrogen gas was simultaneously injected to reduce the aforementioned aqueous solution D of terephthalic acid, and the resulting reduction treatment liquid E was crystallized in the subsequent cry...

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Abstract

This invention related to the method to produce high pure terephthalic acid, this method control the mol ratio of carbon monoxide / (carbon monoxide + hydrogen) at 0.00003 to 0.03 in steam from crystal groove, and this can prolong catalyzer's service life.

Description

[0001] This application is a divisional application. The international application number of the original application is PCT / JP03 / 16464, the Chinese national application number is 200380100394.8, and the application date is December 22, 2003. The title of the invention is "Preparation of high-purity terephthalic acid" method". technical field [0002] The invention relates to a method for preparing high-purity terephthalic acid. Background technique [0003] Generally, the crude product of terephthalic acid obtained by oxidation of p-xylene contains relatively large amounts of various impurities represented by 4-carboxybenzaldehyde (hereinafter referred to as "4CBA"). Esters are used as raw materials. When purifying the terephthalic acid crude product, a method of separation and purification is adopted, the method comprises a dissolution step, a reduction step and a subsequent crystallization step, the dissolution step is to dissolve the terephthalic acid crude product in w...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C63/26C07C51/487C07C51/42C07C51/265
CPCC07C51/487
Inventor 沼田元干矶贝隆行绪方知彦
Owner MITSUBISHI CHEM CORP