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Preparation method of terephthalic acid

A technology of terephthalic acid and acetic acid, applied in carboxylate preparation, organic compound preparation, chemical instruments and methods, etc., can solve the problem of high p-carboxybenzaldehyde content

Active Publication Date: 2014-05-07
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is the excessively high content of p-carboxybenzaldehyde in the crude terephthalic acid produced by air oxidation of p-xylene existing in the prior art

Method used

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  • Preparation method of terephthalic acid
  • Preparation method of terephthalic acid
  • Preparation method of terephthalic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0012] The preparation of terephthalic acid: first according to the mol ratio of quaternary ammonium ion and acetic acid is 25 * 10 -6 (The quaternary ammonium ion is a combination of tetramethylammonium bromide and hexadecyldimethylbenzylammonium bromide, the molar ratio of which is 3:1), and the molar ratio of potassium acetate to acetic acid is 500×10 -6 , The molar ratio of zirconium acetate to acetic acid is 100×10 -6 , the molar ratio of (Co+Mn) to acetic acid is 650×10 -6 , the molar ratio of Co:Mn:Br is 1:1.5:2, the molar ratio of water and acetic acid is 0.05 and the molar ratio of acetic acid and p-xylene is 10. 10mol glacial acetic acid, 18.75×10 -5 mol tetramethylammonium bromide, 6.25×10 -5 mol cetyl dimethyl benzyl ammonium bromide, 500×10 -5 mol potassium acetate, 100×10 -5 mol zirconium acetate, 260×10 -5 molCo(OAc) 2 , 390×10 -5 mol Mn(OAc) 2 , 495×10 -5 Add 1 mol of hydrogen bromide, 0.5 mol of water and 1 mol of p-xylene into the titanium reactor, f...

Embodiment 2

[0015] Carry out the oxidation reaction of p-xylene in the same manner as Example 1, just change the tetramethylammonium bromide added in this embodiment into tetraethylammonium bromide, hexadecyldimethylbenzyl bromide Ammonium is changed to dodecyl dimethyl benzyl ammonium bromide, but the molar amount of its input is not changed, while maintaining the moles of acetic acid, potassium ions, zirconium ions, Co, Mn, Br, water and p-xylene in the reaction system The amount is all constant, then the mass fraction of the terephthalic acid yield of this embodiment gained and 4-CBA in the crude terephthalic acid is shown in Table 1.

Embodiment 3

[0017] Carry out the oxidation reaction of p-xylene in the same manner as Example 1, just change the tetramethylammonium bromide added in this embodiment into trimethylpropylammonium bromide, hexadecyldimethylbenzyl Ammonium bromide is changed to trioctylbenzyl ammonium bromide, but it does not change its input molar weight, while keeping the molar weight of acetic acid, potassium ion, zirconium ion, Co, Mn, Br, water and p-xylene in the reaction system. unchanged, the yield of terephthalic acid obtained in this example and the mass fraction of 4-CBA in the crude terephthalic acid are shown in Table 1.

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Abstract

The invention relates to a preparation method of terephthalic acid, which mainly solves the problem of too high p-carboxybenzaldehyde content in terephthalic acid produced by paraxylene oxidation in the prior art. The method adopts the technical scheme that terephthalic acid is prepared from paraxylene oxidation in the presence of a catalyst and a promoter, wherein the catalyst is a Co-Mn-Br catalyst, the promoter comprises a metal promoter and an ammonium promoter, the metal promoter comprises an alkali metal ion and at least one transition metal ion of Ce<3+>, Nd<3+>, Cr<3+>, Sb<3+>, Hf<4+> or Zr<4+>, and the ammonium promoter comprises a quaternary ammonium ion totally containing 4-8 carbon atoms and a quaternary ammonium ion totally containing 21-30 carbon atoms, so that the problem is better solved, and the method can be used for industrial production of terephthalic acid.

Description

Technical field [0001] The present invention involves a method of preparation of phenyl acidic acid in dysfenyne air. Background technique [0002] PTA polyester industry is an important production process for PTA polyester industry.The cobalt-manganese-bromo composite catalyst is generally used in current industrial production. The price of CO is more expensive. Reducing the amount of CO can reduce the cost of catalyst. For exampleCatalyst) uses HF as a activist. When the reactor adds a HF with a mass score of 30ppm, the amount of CO-MN-BR catalyst can be reduced by 12%, and the generic amount of by-products to the production of carboxylzide (4-cba) can be reduced.10.6%.At the same time, due to the high degree of solubility of HF compounds in acetic acid and water, the amount of residues in p -benzonic acid is small.When the thick phenyl acidic acid was washed with acetic acid / water, the quality score of HF residue was less than 0.3ppm.A certain amount of C 2 , Can significantly...

Claims

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Application Information

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IPC IPC(8): C07C63/26C07C51/265B01J31/32
CPCY02P20/52C07C51/265C07C63/26
Inventor 朱小丽畅延青张绍金
Owner CHINA PETROLEUM & CHEM CORP