Method for producing aromatic carboxylic acid using nitrogen oxide as catalytic additive

A nitrogen oxide, aromatic carboxylic acid technology, applied in the direction of organic compound/hydride/coordination complex catalysts, physical/chemical process catalysts, chemical instruments and methods, etc., can solve the problem of insufficient acceleration effect and increased combustion side reactions , affecting the refining process and other issues, to achieve the effect of reducing emissions, reducing corrosion, and improving product quality

Inactive Publication Date: 2006-11-22
SINOPEC YANGZI PETROCHEM +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But there are also some problems in application, such as the acceleration effect on the reaction is not obvious enough, some also increase the combustion side reaction, some are expensive, and some will have a certain residue in the solid product that will affect the subsequent refining process, etc. Therefore, Affect the practicality of the above technology

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1～5

[0032] Examples 1 to 5: Examples 1-5 are used to illustrate the catalytic activity of different N=O-based heterocyclic compounds at different concentrations as catalytic activators, so as to select suitable N=O-based heterocyclic additives, and the results are shown于表1。 In Table 1.

Embodiment 1

[0034] Add 300 ml of reaction liquid to a 500 ml titanium high-pressure reactor, and pass nitrogen as a protective gas. While stirring, the reaction liquid is heated to 195° C., and the pressure is increased to 1.7 MPa. The composition of the reaction liquid (ie reaction mixture) is 9% (28.05g, 264.5mmol) of p-xylene and 91% (280.5g) of acetic acid, in which the catalyst concentration is 200ppm of cobalt, 350ppm of manganese, 400ppm of bromine and 107ppm N-oxide pyridine (ppm are based on acetic acid, wherein the molar ratio of cobalt, manganese, bromine and N-oxide pyridine is 3:5.63:4.42:1). Cobalt acetate tetrahydrate, manganese acetate tetrahydrate, hydrogen bromide and pyridine N-oxide are used as catalysts. The reaction was carried out at a temperature of 195°C and a pressure of 1.7MPa. During the reaction, high-pressure air was continuously fed with a constant air flow of 12L / min. The oxygen concentration of the exhaust gas was analyzed online by a magnetic oxygen analyzer,...

Embodiment 2

[0036] The oxidation reaction of p-xylene was carried out in the same manner as in Example 1, except that the N-oxypyridine added in this implementation was changed to N-oxypyrimidine, and the added catalyst composition was 200 ppm of cobalt, 350 ppm of manganese, and 400 ppm of manganese. Bromine and 108 ppm N-pyrimidine oxide (ppm are based on acetic acid, wherein the molar ratio of cobalt, manganese, bromine and N-pyrimidine oxide is 3:5.63:4.42:1). When the oxygen consumption reaches 95% of the theoretical total oxygen consumption, it takes 17.13 minutes, and the COX generation amount is 166.6 mmol. The results are shown in Table 1.

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PUM

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Abstract

This invention provides a method for producing aromatic carboxylic acids with oxynitrides as catalytic additive, which is realized by adding a small amount of oxynitrides with specific structures to the current MC-type liquid catalytic system. Compared to the conventional MC type catalytic oxidation process, the adding of oxynitrides with specific structures significantly accelerates the oxidation reaction of the methyl aromatic hydrocarbons, stimulating the process of transforming methyl aromatic hydrocarbons to aromatic carboxylic acids. The adding of oxynitrides with specific structures can also improve the selectivity of the reaction process, and decrease combustion side reaction. Besides, it can moderately decrease the bromine concentration in the system, thus decrease the etching of the reaction system to the apparatus and the bromine-containing toxic gas discharging.

Description

Technical field [0001] The invention discloses an improved method for liquid phase catalytic oxidation of methyl aromatic hydrocarbons to produce aromatic carboxylic acids. Background technique [0002] Since the emergence of the MC method (US2245528) for liquid phase catalytic oxidation of methyl aromatics to produce aromatic carboxylic acids, this method has been widely used in industry. The catalyst used in this method is a cobalt-manganese-bromine ternary composite system, the solvent used is C1-C6 fatty carboxylic acid (usually acetic acid), the reaction temperature is 100-320°C, and the reaction pressure is maintained to make the fatty carboxylic acid solvent In a liquid state. There are many products commercially produced by this method, such as terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, trimellitic acid, 1,2,4-benzenetricarboxylic acid, Acid anhydride, trimellitic acid, pyromellitic dianhydride, benzene pentacarboxylic acid, mellitic...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/265B01J31/02C07C63/04C07C63/15C07C63/307C07C63/313C07C63/337C07D307/89C07D493/04
Inventor 成有为李希刘建新姚小利李晓强
Owner SINOPEC YANGZI PETROCHEM
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