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Method for preparing nylon-46 in supercritical carbon dioxide

A carbon dioxide, supercritical technology, applied in the production of bulk chemicals, can solve problems such as high molecular weight difficulties, and achieve the effect of increasing the polymerization rate, reducing the polymerization temperature, and improving the reaction activity

Active Publication Date: 2012-06-06
JINAN UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although SC-CO 2 It has a certain solubility in water and can increase the molecular weight to about 20,000, but it is difficult to further control and increase the high molecular weight of the product

Method used

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  • Method for preparing nylon-46 in supercritical carbon dioxide
  • Method for preparing nylon-46 in supercritical carbon dioxide
  • Method for preparing nylon-46 in supercritical carbon dioxide

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] Under the condition of stirring, the methanol solution of equimolar amount of 1,4-butanediamine was added dropwise to the methanol solution of 1,6-adipic acid to form a white precipitate; the precipitate was filtered and vacuum-dried to obtain white nylon -46 salt crystals;

[0044] Gained Nylon-46 salt crystallization is placed in the reactor, filled with 99.9vol% high-purity carbon dioxide (CO 2 ), exhaust the air in the kettle, evacuate, replace the air in the kettle, and then pump in CO 2 , to a pressure of 5-7 MPa;

[0045] By adopting the step-by-step heating method, the SC-CO 2 The polycondensation reaction is carried out under certain conditions; the polymerization temperature is gradually raised to 280°C within 6 hours, and the pressure in the kettle is controlled at 20MP;

[0046] After the reaction was over, the temperature was gradually lowered. After cooling to room temperature, the pressure was released, and the kettle was opened to obtain nylon-46 sam...

Embodiment 2

[0049] Under stirring, add an equimolar amount of methanol solution of 1,4-butanediamine dropwise to methanol solution of 1,6-adipic acid to form a white precipitate; filter and dry in vacuum to obtain white nylon-46 salt crystallization;

[0050] A certain amount of nylon-46 salt is placed in the reactor and filled with 99.9vol% high-purity CO 2 , exhaust the air in the kettle, vacuumize, replace the air in the kettle, and then pump in CO 2 , to a pressure of 5-7 MPa;

[0051] By adopting the step-by-step heating method, the SC-CO 2 conditions for the polycondensation reaction. Gradually increase the polymerization temperature to 280°C within 8 hours, and control the pressure in the kettle to 20MP;

[0052] After the reaction was over, the temperature was gradually lowered. Cool to room temperature, release the pressure, and open the kettle to obtain nylon-46 sample 2 as a white solid. Measure the infrared spectrogram of nylon-46 sample 2 as figure 2 shown.

[0053] ...

Embodiment 3

[0055] Under stirring, add an equimolar amount of methanol solution of 1,4-butanediamine dropwise to methanol solution of 1,6-adipic acid to form a white precipitate; filter and dry in vacuum to obtain white nylon-46 salt crystallization;

[0056] A certain amount of nylon-46 salt is placed in the reactor and filled with 99.9vol% high-purity CO 2 , exhaust the air in the kettle, vacuumize, replace the air in the kettle, and then pump in CO 2 , to a pressure of 5-7 MPa;

[0057] By adopting the step-by-step heating method, the SC-CO 2 conditions for the polycondensation reaction. Gradually increase the polymerization temperature to 280°C within 8 hours, and control the pressure in the kettle to 40MP;

[0058] After the reaction was over, the temperature was gradually lowered. Cool to room temperature, release the pressure, and open the kettle to obtain nylon-46 sample 3 as a white solid.

[0059] The relative viscosity-average molecular mass of nylon-46 sample 3 measured ...

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Abstract

The invention discloses a new method for preparing nylon-46 in a supercritical carbon dioxide medium, which comprises the following steps of: adding a 1,4-butanediamine methanol solution into a 1,6-adipic acid methanol solution under the condition of stirring to obtain precipitates; filtering and drying to obtain nylon-46 salt; putting the nylon-46 salt into a reaction kettle, filling carbon dioxide for replacing the air in the kettle, carrying out vacuum-pumping operation, and pumping carbon dioxide; increasing temperature and pressure to enable the carbon dioxide in the kettle to be in a critical state, and carrying out polycondensation reaction of the one-step method in the existence of supercritical carbon dioxide; after the polycondensation reaction, cooling to room temperature, relieving the pressure, and opening the kettle to obtain nylon-46 products of the one-step method; crushing the polycondensation products of the one-step method, and putting the powder into the reaction kettle again to carry out the second-step polycondensation reaction in the existence of supercritical carbon dioxide; and after the second-step polycondensation reaction, cooling to room temperature, relieving the pressure, and opening the kettle to obtain nylon-46 products of a two-step method.

Description

technical field [0001] The invention belongs to the field of high-performance polymer materials, in particular to a method for preparing nylon-46 with high melting point and high molecular weight in supercritical carbon dioxide. Background technique [0002] Polyamide, also known as nylon (Nylon), refers to a polymer containing amide groups in its molecular chain. The macromolecular chain of aliphatic polyamide is composed of amide groups and a certain number of methylene groups. Nylon is a big family, the first member of which is nylon-66, which is currently the most commonly used engineering plastic and fiber material. The numbers of methylene groups between the amide groups of nylon 66 are 6 and 4 respectively, and the melting point is about 260°C. Nylon-46 (polybutylene adipamide) has a similar structure to nylon-66, but the number of methylene groups between the amide groups is 4, and the molecular chain structure is very regular, which improves the crystallization pe...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G69/28C08G69/30
CPCY02P20/54
Inventor 张子勇方欣闪
Owner JINAN UNIVERSITY
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