CN101423623A - Depolymerization and recovery method of high temperature resistant nylon poly-para-phenylene diformyl hexane diamine - Google Patents
Depolymerization and recovery method of high temperature resistant nylon poly-para-phenylene diformyl hexane diamine Download PDFInfo
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Abstract
The invention relates to a method for depolymerizing and recovering high temperature resistant nylon poly(p-phenylene-hexamethylenediamine), which is characterized by comprising the following steps in turn: sodium hydroxide and water are added into a reaction kettle, dissolved, added with crushed nylon PA5T, and subjected to depolymerizaton to obtain a alkali-hydrolyzable liquid; the alkali-hydrolyzable liquid passes through a filter, enters a workshop section of separation and extraction, and is extracted and separated by an arene/alcohol mixed extractant to obtain coarse hexamethylenediamine extract and terephthalic acid sodium salt faffinate; the coarse hexamethylenediamine extract is subjected to distillation and rectification to respectively obtain arene/alcohol/-hexamethylenediamine and arene/alcohol, an organic solvent which is distilled off is replenished with a fresh solvent and can be reused as an extractant, and refined hexamethylenediamine can be obtained after removal of a extracting solvent with low boiling point by means of distillation, and decompression and rectification; and the terephthalic acid sodium salt solution is subjected to decolorization, neutralization, filtration and separation to obtain a terephthalic acid, and a refined terephthalic acid is obtained after water scrubbing and drying of the terephthalic acid. The method has reasonable and practical technology, can reutilize the solvent, reduces the recovery cost, simultaneously reduces environmental pollution, and improves the resource utilization rate.
Description
Technical field
The present invention relates to a kind of high temperature resistant nylon poly paraphenylene terephthalamide method of diamines (PA6T) depolymerization, relate in particular to a kind of method that is applicable to a kind of high temperature resistant nylon PA6T depolymerization that industrialized production is used.
Background technology
Nylon (PA) has excellent mechanical mechanics property, wear resistance, self lubricity, oil-proofness, anti-stability becomes domestic and international application one of plastics the most widely, first of the row five large-engineering plastics.High temperature resistant PA6T is the resin that is formed by terephthalic acid and hexanediamine polycondensation, has the not available characteristic of other nylon, and is particularly particularly remarkable aspect high temperature resistant.In recent years, along with its constantly being applied in a lot of fields, its goods are difficult to handle after being used, and not only cause waste, and environment is polluted, and therefore, recycling high temperature resistant PA6T has remarkable economic efficiency and social benefit.
Nylon reclaims and mainly contains certain methods at present: melt pelletization regeneration; Chemical recovery; Energy recovery; Landfill disposal etc.But because the nylon poor stability, melt pelletization regeneration back mechanical property descends significantly, and can not repeatedly repeat energy recovery is to adopt oil refining or incendiary method, and not only utility value is low, and atmosphere pollution.And landfill is cured the symptoms, not the disease.Therefore, most major companies adopt mostly is chemical recycling.For example sky, Liaoning becomes chemical industry company limited to declare a kind of Chinese patent of production method of useless nylon recycling, and patent publication No. is CN1569802; Shanxi applied chemistry institute has carried out the pilot scale research that hexanodioic acid, hexanediamine are produced in nylon-66 waste material hydrolysis; Minte Nylon Industry Co., Ltd., Ningbo has applied for a kind of Chinese patent of using nylon one 66 depolymerization to produce the technology of hexanodioic acid, hexanediamine, and patent publication No. is CN1611477; Du pont company has carried out the experiment of nitric acid depolymerization nylon-66, with hydrogenation method nitric acid hydrogenation ammonification is made hexanediamine.The patent that adopts the poly-nylon-66 of alkaline hydrolysis was declared in China by Holland DSM N. V. in 1998, publication number is CN1205330A.U.S. Pat A-5302756, USA-5233021 have described a kind of at high temperature by amine and adopt the method depolymerization nylon of supercritical extraction respectively.
Yet, though it is many to produce the company of PA6T, such as E.I.Du Pont Company etc., the document or the patent of not seeing the recovery of relevant PA6T so far.
Summary of the invention
Technical problem to be solved by this invention provides a kind of high temperature resistant nylon poly paraphenylene terephthalamide depolymerization and recovery method of diamines, and its reasonable and practical process can reuse solvent, reduces cost recovery, reduces environmental pollution simultaneously, improves resource utilization.
The present invention solves the problems of the technologies described above the technical scheme that is adopted: the poly-paraphenylene terephthalamide of a kind of high-temperature nylon is the depolymerization and recovery method of diamines, it is characterized in that steps in sequence is an alkali lye depolymerization workshop section, separating and extracting workshop section, the refining workshop section of distillation arranged side by side and in and crystallization workshop section, each workshop section is as described below:
(1), alkali lye depolymerization workshop section, sodium hydroxide and water are added in the reactor, the dissolving back adds the nylon PA6T that pulverizes, and reacts 5～8 hours under the condition that keeps 70-90 ℃ of temperature, pressure 0.1～0.6MPa, obtains alkali solution liquid;
(2), separating and extracting workshop section, alkali solution liquid is entered separating and extracting workshop section through strainer, carry out extracting and separating with aromatic hydrocarbons/alcohols mixed extractant and obtain thick hexanediamine extraction liquid and terephthalic acid sodium salt raffinate;
(3), the refining workshop section of distillation, the thick hexanediamine extraction liquid that obtains in the step (2) is distilled and rectifying, obtain aromatic hydrocarbons/alcohol/hexanediamine respectively, aromatic hydrocarbons/alcohol, the organic solvent that distills can be again as the extraction agent utilization after replenishing fresh solvent, and distillation is removed behind the lower boiling extraction solvent by obtaining the purified hexanediamine after the rectification under vacuum;
(4), in and crystallization workshop section, the terephthalic acid sodium salt solution that step (2) obtains is used activated carbon decolorizing in the decolouring still, add then be equipped with excess sulfuric acid in and in the still, stirring makes and reacts completely, the pH value that makes neutralization back solution is less than 3, filter to isolate terephthalic acid, obtain the purified terephthalic acid after washing, the oven dry.
Concentration sodium hydroxide described in described step (1) the alkali lye depolymerization workshop section is 1%～50%, and is preferred 20%, is mass percent.
Sodium hydroxide described in described step (1) the alkali lye depolymerization workshop section and the mol ratio of PA6T are 2:1～4:1, are preferably 2.5:1.
Aromatic hydrocarbons is benzene, toluene or dimethylbenzene in aromatic hydrocarbons/alcohols mixed extractant described in described step (2) the separating and extracting workshop section, and alcohol is propyl carbinol or primary isoamyl alcohol, and its molar ratio is 1:2～2:1, is preferably 1:1.Compared with prior art, the invention has the advantages that: high temperature resistant nylon poly paraphenylene terephthalamide diamines (PA6T) is carried out depolymerization and recovery, can obtain new high temperature resistant nylon PA6T, reduce environmental pollution, improve resource utilization, and the processing method advantages of simple, can reuse extraction solvent, reduce cost, increase the benefit, very practical.
Description of drawings
Fig. 1 is the process flow diagram of the inventive method;
Fig. 2 is the depolymerization mechanism figure of the inventive method.
Embodiment
Embodiment describes in further detail the present invention below in conjunction with accompanying drawing.
Embodiment 1
In reactor, add 500Kg solid sodium hydroxide and water 1000Kg, add the useless nylon PA6T that pulverizes after the stirring and dissolving, the mol ratio of sodium hydroxide and PA6T is 2:1, stir, under the condition that keeps 70-90 ℃ of temperature, pressure 0.1～0.6MPa, reacted 5～8 hours, make to react completely, obtain alkali solution liquid; Then alkali solution liquid is filtered by coarse filter, remove solid residue, the cooling back adds benzene/propyl carbinol mixed extractant, the mol ratio of extraction agent is 2:1, extract thick hexanediamine, extraction liquid carries out fractionation operation in rectifying tower, continue to serve as extraction agent behind the composite fresh solvent of the organic solvent that distills in the next production cycle; Distillation is carried out rectification under vacuum after removing lower boiling extraction solvent, and control hexanediamine fraction collection temperature is lower than 170 ℃, obtains purity greater than 99.1% hexanediamine; Aforesaid raffinate is the terephthalic acid sodium salt solution, the gac that adds weight ratio 4% in the decolouring still stirs decolouring, adding sulfuric acid is neutralized to pH less than 3 after removing by filter gac, obtaining the crude terephthalic acid solid (slowly adds sulfuric acid while stirring and prevents to dash material, foreign matter content is too high in the terephthalic acid solid that prevents to cause too soon owing to crystallization), wash three times after the filtration with water removing the impurity in the solid and the acid solution of adhering to, obtain purity greater than 99.2% terephthalic acid in oven dry below 80 ℃.
Embodiment 2
In reactor, add 250Kg solid sodium hydroxide and water 1000Kg, add the useless nylon PA6T that pulverizes after the stirring and dissolving, the mol ratio of sodium hydroxide and PA6T is 2.5:1, stir, under the condition that keeps 70-90 ℃ of temperature, pressure 0.1～0.6MPa, reacted 5～8 hours, make to react completely, obtain alkali solution liquid; Then alkali solution liquid is filtered by coarse filter, remove solid residue, the cooling back adds benzene/propyl carbinol mixed extractant, the mol ratio of extraction agent is 1:1, extract thick hexanediamine, extraction liquid carries out fractionation operation in rectifying tower, continue to serve as extraction agent behind the composite fresh solvent of the organic solvent that distills in the next production cycle; Distillation is carried out rectification under vacuum after removing lower boiling extraction solvent, and control hexanediamine fraction collection temperature is lower than 170 ℃, obtains purity greater than 99.7% hexanediamine; Aforesaid raffinate is the terephthalic acid sodium salt solution, the gac that adds weight ratio 3% in the decolouring still stirs decolouring, adding sulfuric acid is neutralized to pH less than 3 after removing by filter gac, obtaining the crude terephthalic acid solid (slowly adds sulfuric acid while stirring and prevents to dash material, foreign matter content is too high in the terephthalic acid solid that prevents to cause too soon owing to crystallization), wash three times after the filtration with water removing the impurity in the solid and the acid solution of adhering to, obtain purity greater than 99.5% terephthalic acid in oven dry below 80 ℃.
Execute example 3
In reactor, add 1000Kg solid sodium hydroxide and water 1000Kg, add the useless nylon PA6T that pulverizes after the stirring and dissolving, the mol ratio of sodium hydroxide and PA6T is 4:1, stir, under the condition that keeps 70-90 ℃ of temperature, pressure 0.1～0.6MPa, reacted 5～8 hours, make to react completely, obtain alkali solution liquid; Then alkali solution liquid is filtered by coarse filter, remove solid residue, the cooling back adds toluene/propyl carbinol mixed extractant, the mol ratio of extraction agent is 1:2, extract thick hexanediamine, extraction liquid carries out fractionation operation in rectifying tower, continue to serve as extraction agent behind the composite fresh solvent of the organic solvent that distills in the next production cycle; Distillation is carried out rectification under vacuum after removing lower boiling extraction solvent, and control hexanediamine fraction collection temperature is lower than 170 ℃, obtains purity greater than 99.3% hexanediamine; Aforesaid raffinate is the terephthalic acid sodium salt solution, the gac that adds weight ratio 3% in the decolouring still stirs decolouring, adding sulfuric acid is neutralized to pH less than 3 after removing by filter gac, obtaining the crude terephthalic acid solid (slowly adds sulfuric acid while stirring and prevents to dash material, foreign matter content is too high in the terephthalic acid solid that prevents to cause too soon owing to crystallization), wash three times after the filtration with water removing the impurity in the solid and the acid solution of adhering to, obtain purity greater than 99.3% terephthalic acid in oven dry below 80 ℃.
Claims (7)
1, a kind of high temperature resistant nylon poly paraphenylene terephthalamide depolymerization and recovery method of diamines is characterized in that steps in sequence is an alkali lye depolymerization workshop section, separating and extracting workshop section, the refining workshop section of distillation arranged side by side and in and crystallization workshop section, each workshop section is as described below:
(1), alkali lye depolymerization workshop section, sodium hydroxide and water are added in the reactor, the dissolving back adds the nylon PA6T that pulverizes, and reacts 5～8 hours under the condition that keeps 70-90 ℃ of temperature, pressure 0.1～0.6MPa, obtains alkali solution liquid;
(2), separating and extracting workshop section, alkali solution liquid is entered separating and extracting workshop section through strainer, carry out extracting and separating with aromatic hydrocarbons/alcohols mixed extractant and obtain thick hexanediamine extraction liquid and terephthalic acid sodium salt raffinate;
(3), the refining workshop section of distillation, the thick hexanediamine extraction liquid that obtains in the step (2) is distilled and rectifying, obtain aromatic hydrocarbons/alcohol/hexanediamine respectively, aromatic hydrocarbons/alcohol, the organic solvent that distills can be again as the extraction agent utilization after replenishing fresh solvent, and distillation is removed behind the lower boiling extraction solvent by obtaining the purified hexanediamine after the rectification under vacuum;
(4), in and crystallization workshop section, the terephthalic acid sodium salt solution that step (2) obtains is used activated carbon decolorizing in the decolouring still, add then be equipped with excess sulfuric acid in and in the still, stirring makes and reacts completely, the pH value that makes neutralization back solution is less than 3, filter to isolate terephthalic acid, obtain the purified terephthalic acid after washing, the oven dry.
2, the depolymerization and recovery method of a kind of high temperature resistant nylon poly hexamethylene terephthalamide according to claim 1 is characterized in that the concentration sodium hydroxide described in step (1) the alkali lye depolymerization workshop section is 1%～50%, is mass percent.
3, the depolymerization and recovery method of a kind of high temperature resistant nylon poly hexamethylene terephthalamide according to claim 2 is characterized in that the concentration sodium hydroxide described in step (1) the alkali lye depolymerization workshop section is 20%, is mass percent.
4, the depolymerization and recovery method of a kind of high temperature resistant nylon poly hexamethylene terephthalamide according to claim 1 is characterized in that sodium hydroxide described in step (1) the alkali lye depolymerization workshop section and the mol ratio of PA6T are 2:1～4:1.
5, the depolymerization and recovery method of a kind of high temperature resistant nylon poly hexamethylene terephthalamide according to claim 4 is characterized in that sodium hydroxide described in step (1) the alkali lye depolymerization workshop section and the mol ratio of PA6T are 2.5:1.
6, the depolymerization and recovery method of a kind of high temperature resistant nylon poly hexamethylene terephthalamide according to claim 1, it is characterized in that aromatic hydrocarbons is benzene, toluene or dimethylbenzene in the aromatic hydrocarbons/alcohols mixed extractant described in step (2) the separating and extracting workshop section, alcohol is propyl carbinol or primary isoamyl alcohol, and its molar ratio is 1:2～2:1.
7, the depolymerization and recovery method of a kind of high temperature resistant nylon poly hexamethylene terephthalamide according to claim 6 is characterized in that aromatic hydrocarbons/pure molar ratio is 1:1 in the aromatic hydrocarbons/alcohols mixed extractant described in step (2) the separating and extracting workshop section.
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102276789A (en) * | 2011-05-15 | 2011-12-14 | 山东莱芜润达化工有限公司 | Method for recovering and utilizing waste and old paper-based copper-coated board non-metallic material |
| CN104017205A (en) * | 2014-06-11 | 2014-09-03 | 李兆顺 | Method for regenerating nylon |
| CN107056624A (en) * | 2017-04-19 | 2017-08-18 | 青岛科技大学 | A kind of alcoholysis recovery method of nylon 66 material |
| CN107325548A (en) * | 2016-03-23 | 2017-11-07 | Ems 专利股份公司 | Heat resistant polyamide molding compounds and its purposes especially in automobile industry |
| CN110563570A (en) * | 2019-09-24 | 2019-12-13 | 中国科学院山西煤炭化学研究所 | Method for preparing terephthalic acid and p-phenylenediamine by degrading p-aramid |
| CN114163622A (en) * | 2021-12-15 | 2022-03-11 | 浙江新和成特种材料有限公司 | Method for preparing biodegradable material by recycling semi-aromatic polyamide waste and product thereof |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5233021A (en) * | 1992-05-13 | 1993-08-03 | Georgia Tech Research Corporation | Recycling of polymeric materials from carpets and other multi-component structures by means of supercritical fluid extraction |
| US5302756A (en) * | 1992-12-23 | 1994-04-12 | E. I. Du Pont De Nemours And Company | Ammonolysis of nylon |
| US5495015A (en) * | 1994-12-12 | 1996-02-27 | Basf Aktiengesellschaft | Process for producing caprolactam through hydrolytic cleavage of molten polycaprolactam |
| CN1205330A (en) * | 1997-05-01 | 1999-01-20 | Dsm有限公司 | Depolymerization of polymides |
| CN1374296A (en) * | 2001-03-14 | 2002-10-16 | 李智范 | Production process of caprolactam with waste nylon 6 |
| CN1324789A (en) * | 2001-06-26 | 2001-12-05 | 中国科学院长春应用化学研究所 | Polyimide hydrolyzing recovery process |
| CN1257880C (en) * | 2003-10-29 | 2006-05-31 | 宁波敏特尼龙工业有限公司 | Process for producing adipic acid and hexanediamine by depolymerization of nylon-66 |
| CN1273434C (en) * | 2004-05-13 | 2006-09-06 | 辽阳天成化工有限公司 | Production method with reclaimed waste nylon as material |
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2007
- 2007-11-02 CN CN2007101564923A patent/CN101423623B/en not_active Expired - Fee Related
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102276789A (en) * | 2011-05-15 | 2011-12-14 | 山东莱芜润达化工有限公司 | Method for recovering and utilizing waste and old paper-based copper-coated board non-metallic material |
| CN102276789B (en) * | 2011-05-15 | 2013-01-23 | 山东莱芜润达化工有限公司 | Method for recovering and utilizing waste and old paper-based copper-coated board non-metallic material |
| CN104017205A (en) * | 2014-06-11 | 2014-09-03 | 李兆顺 | Method for regenerating nylon |
| CN104017205B (en) * | 2014-06-11 | 2017-01-18 | 李兆顺 | Method for regenerating nylon |
| CN107325548A (en) * | 2016-03-23 | 2017-11-07 | Ems 专利股份公司 | Heat resistant polyamide molding compounds and its purposes especially in automobile industry |
| CN107325548B (en) * | 2016-03-23 | 2022-09-23 | Ems 专利股份公司 | High-temperature-resistant polyamide moulding compositions and their use, in particular in the automotive industry |
| CN107056624A (en) * | 2017-04-19 | 2017-08-18 | 青岛科技大学 | A kind of alcoholysis recovery method of nylon 66 material |
| CN110563570A (en) * | 2019-09-24 | 2019-12-13 | 中国科学院山西煤炭化学研究所 | Method for preparing terephthalic acid and p-phenylenediamine by degrading p-aramid |
| CN114163622A (en) * | 2021-12-15 | 2022-03-11 | 浙江新和成特种材料有限公司 | Method for preparing biodegradable material by recycling semi-aromatic polyamide waste and product thereof |
| CN114163622B (en) * | 2021-12-15 | 2023-03-21 | 浙江新和成特种材料有限公司 | Method for preparing biodegradable material by recycling semi-aromatic polyamide waste and product thereof |
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