Method for removing impurity 2,3,4,5-tetrahydropyridine in nylon salt and purified nylon salt

A tetrahydropyridine and nylon salt technology, applied in the separation/purification of carboxylic acid compounds, chemical instruments and methods, purification/separation of amino compounds, etc., can solve the problems of unresolved removal, achieve less impurities, and solve the problem of nylon Effect of yellowing and low content

Active Publication Date: 2016-07-13
CATHAY R&D CENT CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the prior art JP2012106935 suggests a preservation method for reducing the 2,3,4,5-tetrahydropyridine impurity in 1,5-pentanediamine and its salts, it does not provide a method for removing the impurity

Method used

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Examples

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preparation example Construction

[0034] The preparation method of the nylon salt to be purified is not particularly limited in the present invention, and any known method can be used.

[0035] In one embodiment of the present invention, the organic dicarboxylic acid is added into the diamine aqueous solution containing pentamethylenediamine until the pH value in the solution is 5.0-9.5, and the nylon salt aqueous solution to be purified is obtained. In another embodiment of the present invention, the dibasic carboxylic acid and the dibasic amine are weighed and mixed first, and then the mixture is added into water to obtain the nylon salt to be purified. In another embodiment of the present invention, part of the dicarboxylic acid and diamine are weighed and mixed, added to water for reaction, and then the rest of the dicarboxylic acid or diamine is added to prepare the nylon salt to be purified.

[0036] Furthermore, not all nylon salts to be purified are prepared from pure diamines and diacids. For example...

Embodiment 2

[0063] Embodiment 2 pentamethylenediamine sebacate

[0064] Concentrate 5wt% 1,5-pentanediamine aqueous solution in a single-effect evaporator with an evaporating pressure of -0.09MPa, heat it with steam at 121°C, and gradually increase the concentration to obtain 1,5-pentanediamine with a content of 15wt%. Concentrated aqueous solution of pentamethylenediamine.

[0065] Replace the air in the 100-liter enamel salt-forming kettle by vacuuming and filling it with nitrogen three times, and protect it with nitrogen. Add 50 kg of the above-mentioned concentrated aqueous solution of 1,5-pentanediamine to the salt-forming kettle, and heat the solution to 60°C while stirring. And adding sebacic acid (Hebei Hengshui Dongfeng Chemical Co., Ltd.) to the solution to adjust the pH of the solution to 8.5 to obtain a solution of pentamethylenediamine sebacate to be purified.

[0066] Sampling and analysis of the above-mentioned nylon salt solution to be purified showed that the content of ...

Embodiment 3

[0069] Embodiment 3 pentamethylenediamine adipate

[0070] Concentrate 10wt% aqueous solution of 1,5-pentanediamine (containing 4% butanol) in a single-effect evaporator with an evaporating pressure of -0.09MPa, heat it with steam at 121°C, and gradually increase the concentration to obtain 1,5-pentanediamine A concentrated aqueous solution of 1,5-pentanediamine (containing 0.8% butanol) with a diamine content of 25 wt%.

[0071] Replace the air in a 100-liter enamel salt-forming kettle by vacuuming and filling it with nitrogen three times, and protect it with nitrogen. Adipic acid was added to the solution to adjust the pH of the solution to 8.2 to obtain a solution of pentamethylenediamine adipate to be purified.

[0072] Sampling and analysis of the above-mentioned nylon salt solution to be purified showed that the content of 2,3,4,5-tetrahydropyridine relative to 1,5-pentanediamine was 0.35% (normalized method).

[0073] Add 1 kg of wooden macroporous powdered activated ...

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PUM

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Abstract

The present invention provides a purified nylon salt formed from diamines and dicarboxylic acids, the diamines at least comprise 1,5-Diaminopentane, the content of impurity 2,3,4,5-tetrahydropyridine in the nylon salt is less than 0.1wt%, and the content is calculated on the basis of the weight of the 1,5-Diaminopentane. The present invention further provides a method for removing the impurity 2,3,4,5-tetrahydropyridine in the nylon salt. Compared with conventional nylon salts, the purified nylon salt has the characteristics of less impurities in particular low content of the impurity 2,3,4,5-tetrahydropyridine, and the yellowing problem of nylon obtained by subsequent polymerization can be effectively solved.

Description

technical field [0001] The invention relates to a method for removing 2,3,4,5-tetrahydropyridine impurity in nylon salt, specifically a method capable of controlling the content of impurity 2,3,4,5-tetrahydropyridine in nylon salt at relatively low Low range process and resulting purified nylon salt. Background technique [0002] Polyamide is an important class of textile materials and engineering plastics. Polyamide series products such as polyamide 56, polyamide 510, polyamide 512, etc. prepared from pentamethylenediamine (1,5-pentamethylenediamine, or 1,5-diaminopentane) as monomers can be used in textile , electronic appliances, mechanical equipment, auto parts and other aspects of daily production and life. [0003] Nylon can be made by direct polycondensation of diamines and dibasic acids, or nylon salts can be produced from polymerized monomers first, and then the nylon salts can be polymerized. The polymerization reaction usually needs to be carried out at a tempe...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C211/09C07C209/00C07C209/86C07C51/41C07C51/47C07C55/14C07C55/20C07C55/21C07C63/28C08G69/26
Inventor 秦兵兵刘驰郭善诗戴端芳郑毅
Owner CATHAY R&D CENT CO LTD
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