Method for replacing p-xylene in crude terephthalic acid filter cake

A technology of crude terephthalic acid and p-xylene, applied in the separation/purification of carboxylic acid compounds, organic chemistry, etc., can solve the problem of high content of p-xylene

Active Publication Date: 2013-05-29
CHINA PETROLEUM & CHEM CORP +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The technical problem to be solved by the present invention is the problem that the residual p-xylene content in the crude terephthalic acid filter cake is too high in the prior art, and a method for replacing p-xylene in the crude terephthalic acid filter cake is provided. The method has the characteristics of low residual p-xylene content in the crude terephthalic acid filter cake and good compatibility with the subsequent hydrofining process and polymerization process

Method used

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  • Method for replacing p-xylene in crude terephthalic acid filter cake

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Embodiment 1

[0011] 8 kg of acetic acid slurry with 36% by weight concentration of crude terephthalic acid from the oxidation reactor was filtered in a filter to obtain a crude terephthalic acid filter cake containing 10% by weight of acetic acid. Then, wash the crude terephthalic acid filter cake with 1.5 times the weight of the crude terephthalic acid filter cake and be heated to 70°C for beating and washing the crude terephthalic acid filter cake, and filter to obtain a p-xylene containing 8% by weight percentage. Crude Terephthalic Acid Cake I.

[0012] Use the sodium lauryl sulfate aqueous solution of 0.5% concentration by weight to carry out beating and washing according to the weight equivalent to 1.5 times of the terephthalic acid filter cake I, then filter and analyze the acetic acid and p-xylene in the filter cake II obtained by sampling content, and the results are shown in Table 1.

[0013] In order to check the impact of residual surfactant on the crude terephthalic acid hydr...

Embodiment 2～26

[0016] Except that the type of surfactant, the concentration of surfactant, and the amount of aqueous surfactant solution are different, other operating conditions are the same as in Example 1. The changes in operating conditions and the experimental results are shown in Table 1.

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Abstract

The invention relates to a method for replacing p-xylene in a crude terephthalic acid filter cake, and is mainly used for solving the problem that in the prior art, residual p-xylene in the crude terephthalic acid filter cake is overhigh in content. The method comprises the following steps of: (a) washing the crude terephthalic acid containing acetic acid by p-xylene and filtering to obtain filter cake I; and (b) washing the filter cake I by a surfactant aqueous solution represented by formula R<1>O(CH2CH2O)nR<2>, and then filtering to obtain filter cake II, wherein R<1> in the surfactant molecules represents C12-18 alkyl or phenyl, R<2> represents C1-8 alkyl, and n represents the number of CH2CH2O structural units and is 3-15. With the adoption of the technical scheme, the problem is better solved, and the method can be applied to industrial production of terephthalic acid.

Description

technical field [0001] The invention relates to a method for replacing p-xylene in a crude terephthalic acid filter cake. Background technique [0002] Terephthalic acid is usually obtained by liquid-phase oxidation of p-xylene in acetic acid solvent with Co-Mn-Br as a catalyst. The crude terephthalic acid obtained by the above method needs further hydrofining to remove p-carboxybenzaldehyde (4-CBA), p-toluic acid (PT acid) and some colored impurities to obtain purified terephthalic acid. Before hydrofining, the acetic acid in the crude terephthalic acid slurry must be removed to prepare a terephthalic acid aqueous slurry. The traditional process is to remove the acetic acid in the crude terephthalic acid mother liquor by centrifugal filtration and drying equipment, and then beat with water to obtain a terephthalic acid water-based slurry. The drying process of this process consumes a lot of energy and the cost of the drying equipment is high. . [0003] In order to solve...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C63/26C07C51/42
Inventor 朱庆才畅延青陈大伟
Owner CHINA PETROLEUM & CHEM CORP
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