Nylon 6 oligomer depolymerization residue treatment process

A treatment process and oligomer technology, applied in the direction of organic chemistry, separation/purification of lactam, chemical instruments and methods, etc., can solve the problem of difficult residue treatment, achieve low cost, improve utilization rate, and save treatment cost Effect

Pending Publication Date: 2022-06-07
浙江恒逸锦纶有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In order to overcome the problem that the residue produced by nylon polymerization contains phosphoric acid, caustic soda and other substances that are difficult to handle, the present invention provides a treatment process for the depolymerization residue of nylon 6 oligomers, which fully stirs and mixes the residue after depolymerization and dehydration to remove the residue The acid and base in the medium, and then use the different melting points to separate the oligomers

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] A kind of nylon 6 oligomer depolymerization residue treatment process, the steps are as follows:

[0023] (1) Heat up the depolymerized residue of nylon 6 oligomer to 230 °C, and it is in a molten state, add the dehydration residue, stir for 3 h, then add sodium hydroxide solution, adjust the pH to neutral;

[0024] (2) After the mixture is cooled to room temperature, filter, then add water and filter until the pH of the filtrate 1 is 7;

[0025] (3) Heat the filtrate 1 to 220 °C, continue stirring for 3 h, add cooling water, adjust the temperature to 20 °C, crystallize the oligomers, and filter to obtain filtrate 2;

[0026] (4) Transfer the filtrate 2 into a centrifuge, centrifuge at 500 rpm for 10 min, and centrifuge twice;

[0027] (5) The filtrate after centrifugation is put back into the depolymerization tower for depolymerization, and steps (1)-(5) are repeated 4 times.

[0028] After repeating 4 times, the filtrate 1 of step (3) could no longer separate the fi...

Embodiment 2

[0030] A kind of nylon 6 oligomer depolymerization residue treatment process, the steps are as follows:

[0031] (1) Heat up the residue after depolymerization of nylon 6 oligomer to 240 ℃, and it is in a molten state, add the dehydration residue, stir for 3 h, then add sodium hydroxide solution, adjust the pH to neutral;

[0032] (2) After the mixture is cooled to room temperature, filter, then add water and filter until the pH of the filtrate 1 is 7;

[0033] (3) Heat the filtrate 1 to 240 °C, continue stirring for 3 h, add cooling water, adjust the temperature to 10 °C, crystallize the oligomer, and filter to obtain filtrate 2;

[0034] (4) Transfer the filtrate 2 into a centrifuge, and perform centrifugation at 1000 rpm for 15 min;

[0035] (5) The filtrate after centrifugation is put back into the depolymerization tower for depolymerization, and steps (1)-(5) are repeated 3 times.

[0036] After repeating 3 times, the filtrate 1 of step (3) could no longer separate the ...

Embodiment 3

[0038] A kind of nylon 6 oligomer depolymerization residue treatment process, the steps are as follows:

[0039] (1) Heat up the residue after depolymerization of nylon 6 oligomer to 220 ℃, and it is in a molten state, add the dehydration residue, stir for 3 h, then add sodium hydroxide solution, adjust the pH to neutral;

[0040] (2) After the mixture is cooled to room temperature, filter, then add water and filter until the pH of the filtrate 1 is 7;

[0041] (3) Heat the filtrate 1 to 230 °C, continue stirring for 3 h, add cooling water, adjust the temperature to 15 °C, crystallize the oligomers, and filter to obtain filtrate 2;

[0042] (4) Transfer the filtrate 2 into a centrifuge, centrifuge at 800 rpm for 15 min, and centrifuge 3 times;

[0043] (5) The filtrate after centrifugation is put back into the depolymerization tower for depolymerization, and steps (1)-(5) are repeated twice.

[0044] After repeating twice, the filtrate 1 in step (3) could no longer separate ...

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PUM

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Abstract

The invention relates to the field of waste recovery and treatment, and provides a chinlon 6 oligomer depolymerization residue treatment process aiming at the problem that substances containing phosphoric acid, caustic soda and the like in residues generated by chinlon polymerization are difficult to treat, and the chinlon 6 oligomer depolymerization residue treatment process comprises the following steps: (1) heating chinlon 6 oligomer depolymerization residues to a molten state, adding dehydrated residues, uniformly mixing to obtain a mixed solution, adjusting the pH value of the mixed solution to 6-8, and carrying out solid-liquid separation; filtering to obtain filtrate I; (2) heating the filtrate I to 220-240 DEG C, cooling to crystallize the oligomer, and filtering the cooling liquid to obtain filtrate II and filter residues; and (3) further depolymerizing the filtrate II to obtain oligomer depolymerized residues, and repeating the steps (1)-(3) until filter residues cannot be separated from the filtrate I. According to the method, the depolymerized residues and the dehydrated residues are mixed for reaction, high-risk chemical substances such as phosphoric acid and caustic soda in the residues are removed through acid-base neutralization, and caprolactam and oligomers are effectively separated by utilizing different solubility of caprolactam and caprolactam oligomers.

Description

technical field [0001] The invention relates to the field of recycling and processing of waste materials, in particular to a process for treating the depolymerization residue of nylon 6 oligomers. Background technique [0002] Nylon 6 is an important class of products in the textile field. Nylon 6 mainly generates polymer melt through caprolactam polymerization, and caprolactam polymerization is a reversible reaction, which will inevitably produce oligomers with lower molecular weight during the polymerization process. The oligomers are separated from the melt, and the separated melt enters subsequent steps such as pelletizing and spinning, and the oligomers left by the extraction are generally purified by Lurgi’s oligomer recovery process, and the oligomers are Purification by steps such as depolymerization, dehydration, distillation, etc., for example, patent CN01106917.1 discloses a method for recycling the extraction agent to distill the raffinate, distilling the raffin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D223/10C07D201/16
CPCC07D223/10C07D201/16Y02W30/62C08J2377/02C08J11/14
Inventor 宋广旭刘学军
Owner 浙江恒逸锦纶有限公司
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