Method for preparing high-molecular-weight nylon-46 in supercritical carbon dioxide

A carbon dioxide, high molecular weight technology, applied in the production of bulk chemicals, etc., can solve the problems of long post-solid-phase polycondensation reaction time, many operation procedures, and inability to achieve, and achieve the effects of environmental friendliness, simple operation steps, and energy saving.

Active Publication Date: 2013-02-13
JINAN UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Its disadvantages are that the reaction kettle needs to be opened, there are many operating procedures, energy consumption, and the post-solid phase polycondensation reaction time is long
According to the method described in this patent, it is impossible to obtain nylon-46 with high relative molecular weight, such as 40,000g / mol, 50,000g / mol or more

Method used

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  • Method for preparing high-molecular-weight nylon-46 in supercritical carbon dioxide
  • Method for preparing high-molecular-weight nylon-46 in supercritical carbon dioxide
  • Method for preparing high-molecular-weight nylon-46 in supercritical carbon dioxide

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] Embodiment 1 has the preparation of the nylon-46 salt of different pH values

[0046] According to the molar ratio of 1,4-butanediamine to 1,6-adipic acid shown in Table 1, 1,4-butanediamine and 1,6-adipic acid were dissolved in absolute ethanol, respectively. Under stirring conditions, the ethanol solution of 1,4-butanediamine was added dropwise to the ethanol solution of 1,6-adipic acid, and precipitation occurred. After filtration, the white nylon 46 salt was obtained, which was dried under vacuum at 70°C.

[0047] Weigh the newly prepared nylon-46 salt, and make a solution with a mass concentration of 1% with distilled water. Use a pH meter (PHS-3C type) to measure the pH value of the solution. The pH values ​​of nylon-46 salts prepared from different molar ratios (1,4-butanediamine / 1,6-adipic acid) are listed in Table 1.

[0048] Table 1 pH value of nylon-46 salt

[0049]

[0050] This table shows that with the increase of the added amount of 1,4-butanediami...

Embodiment 2

[0053] With the nylon-46 salt of the different pH values ​​that example 1 prepares in SC-CO 2 Synthetic nylon-46.

[0054] Put the nylon-46 salt in the reactor and fill it with 99.9vol% high-purity CO 2 , exhaust the air in the kettle, vacuumize, replace the air in the kettle, and then pump in liquid CO 2 , until the pressure inside the kettle is 7MPa;

[0055] The reactor was heated to 190°C, the pressure inside the reactor was adjusted to 30MPa, and the precondensation reaction was carried out for 2 hours under this condition. After the reaction, remove the CO in the kettle 2 , re-pump liquid CO 2 .

[0056] The reaction kettle is heated to 280°C, and the pressure inside the kettle can reach 15MPa at this time. Under these conditions, the post-solid phase polycondensation reaction was carried out for 3h.

[0057] After the reaction was over, the pressure was released. Use a vacuum pump to depressurize, maintain the temperature in the kettle at 280°C to 270°C, and the...

Embodiment 3

[0064] The nylon-46 salt that is 7.26 with the pH value that example 1 prepares is in SC-CO 2 Synthetic nylon-46.

[0065] Put the nylon-46 salt in the reactor and fill it with 99.9vol% high-purity CO 2, exhaust the air in the kettle, vacuumize, replace the air in the kettle, and then pump in liquid CO 2 , until the pressure inside the kettle is 7MPa;

[0066] Heat the reactor to 180°C, adjust the pressure inside the reactor to 30MPa, and carry out the precondensation reaction for 2 hours under this condition. After the reaction, remove the CO in the kettle 2 , re-pump liquid CO 2 .

[0067] The reaction kettle is heated to 280°C, and the pressure inside the kettle can reach 15MPa at this time. Under these conditions, the post-solid phase polycondensation reaction was carried out for 3h.

[0068] After the reaction was over, the pressure was released. Use a vacuum pump to depressurize, maintain the temperature in the kettle at 280°C to 270°C, and the pressure in the ke...

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Abstract

The invention discloses a new method for preparing high-molecular-weight nylon-46 in supercritical carbon dioxide. The method comprises the following steps of: (1) adding ethanol solution of 1,4-butanediamine with excessive molar ratio into ethanol solution of 1,6-adipic acid dropwise under stirring to obtain alkaline nylon-46 salt; (2) placing the nylon-46 salt into a reaction kettle, introducing carbon dioxide gas, exhausting air in the kettle and pumping liquid carbon dioxide; and (3) heating the reaction kettle, performing prepolycondensation, rear solid phase polycondensation and polymerization under vacuum on the nylon-46 salt in the supercritical carbon dioxide sequentially, and discharging to obtain the high-molecular-weight nylon-46. The method has the biggest advantage of obtaining the nylon-46 with the relative viscosity average molecular weight of over 50,000 g / mol. The new method for preparing the high-molecular-weight nylon-46 is created.

Description

technical field [0001] The invention relates to the field of high-performance polymer materials, in particular to a method for preparing high-molecular-weight nylon-46 in supercritical carbon dioxide. Background technique [0002] Polyamide, also known as nylon, is an important engineering plastic and synthetic fiber. Nylon-46 is an important member of the aliphatic nylon family. It has the characteristics of high melting point, high crystallinity, high temperature resistance and high strength. It has outstanding performance and is widely used. [0003] The molecular chain structure of nylon-46 is regular (the chemical structural formula is as follows), and there are 4 methylene groups between the two amide bonds, so the melting point is high and the crystallinity is high. The melting point of nylon-46 is above 300°C, which is 40°C to 50°C higher than that of commonly used nylon 66. If the melt polycondensation method is used to prepare nylon-46, the reaction temperature m...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G69/30
CPCY02P20/54
Inventor 张子勇黄凯金
Owner JINAN UNIVERSITY
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