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Method for preparing high-purity naphthalic acid by taking beta-methylnaphthalene as raw material

A technology of naphthalene dicarboxylic acid and methylnaphthalene, which is applied in the field of coal chemical industry, can solve the problems of difficulty in obtaining raw materials and high cost, and achieve the effect of abundant sources, mild reaction conditions and high purity

Pending Publication Date: 2019-08-09
BEIJING INSTITUTE OF PETROCHEMICAL TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] At present, the biggest problem in the production of 2,6-NDCA by oxidation of 2,6-dialkylnaphthalene is the difficulty in obtaining raw materials, and the high cost of preparation, separation and purification of high-purity 2,6-dialkylnaphthalene
2,6-Dimethylnaphthalene, 2,6-Diethylnaphthalene and 2,6-Diisopropylnaphthalene decrease successively according to the oxidation activity, but according to the sources of raw materials, high-purity 2,6-Diisopropylnaphthalene can be obtained The cost of isopropylnaphthalene is much lower than that of 2,6-dimethylnaphthalene. The melting point difference between 2,6-dimethylnaphthalene and 2,7-dimethylnaphthalene is only 0.5°C, and it is difficult to separate them by conventional separation methods; while 2,6-diisopropylnaphthalene and 2,7-dimethylnaphthalene The melting points of isopropylnaphthalene are 69°C and -3°C respectively, and the boiling points also differ by 2.9°C. It is relatively easy to separate the two

Method used

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  • Method for preparing high-purity naphthalic acid by taking beta-methylnaphthalene as raw material
  • Method for preparing high-purity naphthalic acid by taking beta-methylnaphthalene as raw material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Put the stirred reactor into a low-temperature tank, add 300g of nitrobenzene, then add 50g of anhydrous aluminum trichloride, and finally add 26g of propionyl chloride, control the temperature at 0°C, and react for 10 minutes to prepare an acylation solution. Add 300g of nitrobenzene in a stirred reactor, and then add 30g of 2-methylnaphthalene to prepare a raw material solution. The two materials were mixed and reacted in a stirring reactor, the reaction time was 120min, and the reaction temperature was controlled at 35°C. The reacted products enter the hydrolysis reactor, and the reaction temperature is controlled at 40°C. After washing with water, distill under reduced pressure to obtain a crude product, which is then recrystallized with methanol containing 20% ​​water. Finally, 2-methyl-6-propionylnaphthalene with a yield of 91% and a purity of 98.5% can be obtained.

[0034] Add 2-methyl-6-propionylnaphthalene to the gas-liquid stirred bubbling reactor, add 100g...

Embodiment 2

[0036] Put the stirred reactor into a low-temperature tank, add 200g of nitrobenzene, then add 35g of anhydrous aluminum trichloride, and finally add 20g of propionyl chloride, control the temperature at 5°C, and react for 15 minutes to prepare an acylation solution. Add 200g of nitrobenzene in a stirred reactor, and then add 22g of 2-methylnaphthalene to prepare a raw material solution. The two materials were mixed and reacted in a stirring reactor, the reaction time was 180min, and the reaction temperature was controlled at 40°C. The reacted products enter the hydrolysis reactor, and the reaction temperature is controlled at 50°C. After washing with water, distill under reduced pressure to obtain a crude product, which is then recrystallized with methanol containing 10% water. Finally, 2-methyl-6-propionylnaphthalene with a yield of 90% and a purity of 98.6% can be obtained.

[0037] Add 2-methyl-6-propionylnaphthalene to the gas-liquid stirred bubbling reactor, add 80g gl...

Embodiment 3

[0039] Put the stirred reactor into a low-temperature tank, add 100g of nitrobenzene, then add 20g of anhydrous aluminum trichloride, and finally add 9g of propionyl chloride, control the temperature at 0°C, and react for 30 minutes to prepare an acylation solution. Add 100 g of nitrobenzene into a stirred reactor, and then add 10 g of 2-methylnaphthalene to prepare a raw material solution. The two materials were mixed and reacted in a stirring reactor, the reaction time was 60min, and the reaction temperature was controlled at 25°C. The reacted products enter the hydrolysis reactor, and the reaction temperature is controlled at 30°C. After washing with water, distill under reduced pressure to obtain a crude product, and then recrystallize with methanol containing 30% water. Finally, 2-methyl-6-propionylnaphthalene with a yield of 90% and a purity of 98.8% can be obtained.

[0040] Add 2-methyl-6-propionylnaphthalene to the gas-liquid stirred bubbling reactor, add 70g glacia...

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Abstract

The invention discloses a method for preparing high-purity naphthalic acid by taking beta-methylnaphthalene as a raw material. The method comprises the following steps of (1) preparation of an acylation solution, wherein propionyl chloride is added into nitrobenzene and anhydrous aluminium trichloride, and it is controlled that the temperature is below 0 DEG C, so that a mixed solution is mixed into a uniform and transparent solution; (2) an acylation reaction, wherein the acylation solution obtained in step (1) is added into a nitrobenzene solution of 2-methylnaphthalene dropwise, it is controlled that the temperature is below 0 DEG C, and the acylation reaction is carried out; (3) hydrolysis of an acylate, wherein distilled water is added into the product obtained in step (2) for cleaning until the pH value of a mixed solution is 6-7; (4) reduced pressure distillation, wherein the product obtained in step (3) is subjected to reduced pressure distillation, the acylate flows out at 165-180 DEG C, cooling is carried out, and a white solid is obtained; (5) purification of the acylate, wherein the product obtained in step (4) is purified by using a recrystallization method, 2-methyl-6-propiononaphthone is obtained, and vacuum drying is carried out; (6) an oxidation reaction, wherein the product obtained in step (5) is synthesized into 2,6-NDA through an air liquid phase oxidationreaction technology.

Description

technical field [0001] The invention belongs to the technical field of coal chemical industry, and in particular relates to a method for preparing high-purity naphthalene dicarboxylic acid by using β-methylnaphthalene as a raw material. Background technique [0002] my country is rich in coal reserves. In today's increasingly tense energy environment, it is of great significance to develop a high value-added route for naphthalene as a measure to increase the comprehensive utilization of heavy components in energy such as coal and petroleum. 2,6-Naphthalene dicarboxylic acid is a key monomer for the synthesis of various high-performance polynaphthyl esters, polyurethanes and liquid crystal polyester resins (LCP), especially polyethylene naphthalate prepared by reacting with ethylene glycol All aspects of physical and chemical properties are superior to polyethylene terephthalate, which is widely used at present, and it has broad application prospects in the fields of fibers, ...

Claims

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Application Information

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IPC IPC(8): C07C51/265C07C63/38
CPCC07C51/04C07C51/265C07C51/58C07C63/68C07C63/36C07C63/38
Inventor 靳海波杨索和何广湘郭晓燕马磊
Owner BEIJING INSTITUTE OF PETROCHEMICAL TECHNOLOGY
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