A kind of preparation method of nylon salt

A nylon salt and solution technology, applied in the field of nylon salt preparation, can solve the problems of high saturated solubility of nylon salt, poor quality of nylon salt, low yield of nylon salt, etc. Effects of by-product impurities

Active Publication Date: 2019-01-29
CATHAY R&D CENT CO LTD +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the high saturation solubility of nylon salt, the yield of nylon salt is often very low in the process of precipitation and crystallization
At the same time, processes such as heating and concentration will also have a negative impact on the quality of nylon salt

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0020] In the preparation method of the nylon salt of the present invention, the temperature of the solution can be kept stable, and the solid nylon salt can be reacted into a salt without going through the usual heating and cooling process, which not only simplifies the preparation process, but also has a thorough reaction, and the precipitated nylon salt is solid. The absence of amine residues not only improves the purity and quality of nylon salt, but also facilitates the subsequent processing of nylon salt. It also avoids the harm of toxic substances such as diamines to the laboratory personnel and the environment; at the same time, the saturated nylon obtained after solid-liquid separation The salt solution can be reused to prepare nylon salt. The nylon salt obtained by the preparation method of the present invention has large crystal particles and high product purity. It can be stored and transported over a long distance without further processing. The obtained nylon salt ...

Embodiment 1

[0056] 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. At 30°C, add 25kg of 1,5-pentanediamine adipic acid nylon salt saturated solution to the salt-forming kettle. Keeping the above temperature and vigorous stirring, continue to add a certain amount of 1,5-pentanediamine and adipic acid in an equimolar ratio to the salt formation reactor to make the weight concentration of the total salt reach 68%. The reaction system is in the suspension slurry. Under the state, the solid-liquid mixing and the salt-forming reaction are realized, and then the nylon salt is precipitated, and the stirring is continued for 2 hours. The pH of the reaction system is tested at 7.5, the salt-forming reaction is completed, and the nylon salt product is crystal. Directly filter at 30°C, and after liquid-solid separation, place the nylon salt solid obtained in a vacuum oven at 50-60°C for 4-5 hours to obtain wh...

Embodiment 2

[0058] 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. Add 15 kg of water to the salt-forming kettle at 50°C, maintain the above temperature and vigorously stir, and react to salt formation. Add a certain amount of 1,5-pentanediamine and adipic acid in an equimolar ratio to the kettle, so that the weight concentration of the total salt reaches 70% (the salt accounts for the weight of the entire solid), and the reaction system is solid-liquid in the state of suspended slurry Mix and neutralize the salt-forming reaction, and then precipitate nylon salt, continue to stir for half an hour, adjust the pH of the reaction system to 7.8, the salt-forming reaction ends, and the nylon salt product is crystalline. After cooling to 30℃ and centrifugation directly, after liquid-solid separation, the obtained nylon salt wet solid was dried in a vacuum oven at 50-60℃ for 4-5 hours to obtain white nyl...

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PUM

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Abstract

The invention provides a preparation method of a nylon salt. The method comprises the following steps: 1, providing a saturated nylon salt solution; 2, adding a diamine and a diacid to the solution provided in step 1 to precipitate a nylon salt solid from the solution; and 3, carrying out solid-liquid separation on the product obtained in step 2 to obtain the nylon salt solid. The preparation method of the nylon salt has the following advantages: the reaction temperature range of a reaction system is wide, and especially the reaction can be carried out at room temperature, so reaction conditions are mild; and high temperature heating is avoided, so energy consumption is reduced, and byproduct impurities generated in high temperature reactions are reduced, thereby the nylon yellowing phenomenon in the subsequent polymerization process of the nylon salt is mitigated.

Description

Technical field [0001] The invention relates to a method for preparing nylon salt, in particular to a method for preparing nylon salt in liquid phase at low temperature. Background technique [0002] Nylon can be made by the polycondensation reaction of dibasic acid and diamine. In the nylon synthesis, in order to ensure the equimolar ratio of the dibasic acid and the diamine raw materials as much as possible, the method of making nylon salt first and then polycondensing is usually adopted. Therefore, as a precursor of nylon polymer, the product quality of nylon salt has a huge impact on the quality of nylon polymer. Qualified nylon salt is the basic prerequisite for the production of high-quality nylon polymers. The quality of nylon salt is affected by many factors, such as production process, monomer production method, and raw material types. [0003] In summary, how to obtain nylon salt with less impurities, high yield and high quality has become a key issue in nylon producti...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C211/09
Inventor 杨晨秦兵兵郑毅刘驰李乃强刘修才
Owner CATHAY R&D CENT CO LTD
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