CN101565374B - Method for depolymerizing waste polyester - Google Patents
Method for depolymerizing waste polyester Download PDFInfo
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- CN101565374B CN101565374B CN2009100813595A CN200910081359A CN101565374B CN 101565374 B CN101565374 B CN 101565374B CN 2009100813595 A CN2009100813595 A CN 2009100813595A CN 200910081359 A CN200910081359 A CN 200910081359A CN 101565374 B CN101565374 B CN 101565374B
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- depolymerization
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- cosolvent
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/582—Recycling of unreacted starting or intermediate materials
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- Separation, Recovery Or Treatment Of Waste Materials Containing Plastics (AREA)
Abstract
The invention provides a method for depolymerizing waste polyester, which comprises the following steps of: adding methanol and cosolvent gas into a reaction system and utilizing the methanol and the cosolvent gas for depolymerizing waste polyester-polyethylene glycol terephthalate material so as to obtain dimethyl terephthalate and ethylene glycol on thesupercritical condition. According to the invention, as the cosolvent is added, the depolymerizing reaction temperature of the waste polyester is lowered and the reaction time is shortened, thereby reducing the energy consumption. As the cost of the cosolvent is relatively lower and easy for recycling, the recycling cost of the waste polyester is further lowered. In the method, the degradation rate of the olyethylene glycol terephthalate is more than 99.9 percent, the monosomic selectivity is high, and the content of oligomers in the product is low.
Description
Technical field
The present invention relates to a kind of waste and old polyester depolymerization method, be specifically related to utilize methyl alcohol and cosolvent disaggregation of waste and old polyester under super critical condition---the method for polyethylene terephtalate waste material.
Background technology
PET (polyethylene terephthalate) is the saturated polyester of terephthalic acid and terepthaloyl moietie.It all is widely used in the wrapping material of industries such as food, beverage, chemical industry, medicine, makeup.The fast development of PET industry, incident is the sharp increase of its waste material, as reasonably not recycling, not only causes the huge wasting of resources, and can produce the serious environmental pollution.
Waste PET has strong resistivity to atmosphere and biological reagent.Recycle to PET is main with chemical cycle mainly, and the ester bond of PET very easily receives solvent action and causes splitting of chain, and degraded reagent difference can obtain various degraded products.The degraded of PET can be divided into several types, promptly acid depolymerization, alkaline depolymerization and methyl alcohol depolymerization.Acid, alkali hydrolysis method generally need to carry out under higher acidity or the alkaline condition, can produce a large amount of acid, alkali wasteliquid, contaminate environment after the depolymerization.The terepthaloyl moietie depolymerization is a kind of common depolymerization method; Polyethylene terephthalate under the catalyzer existence condition with excessive glycol reaction; Product is diglycol terephthalate and terepthaloyl moietie, but has a small amount of glycol ether in the product after the depolymerization, influences the quality and the color and luster of product.The methyl alcohol depolymerization is divided into normality methyl alcohol depolymerization and supercritical methanol depolymerization.Normality methyl alcohol depolymerization can be divided into the low-voltage and medium voltage depolymerization again.The low pressure depolymerization rate is lower, and depolymerization needs about 10 hours fully.
Document 1, European patent [EUR.0662466A1, (1995)] report; PET carries out depolymerization reaction at 240-300 ℃ under the 0.2-0.7MPa, the reaction pair equipment requires lower; Be easy to realize operate continuously, but speed of reaction is lower, the polyester transformation efficiency is lower; And also have some oligopolymer in the product, that gives reactant refiningly brings certain difficulty.
[GB.Patent 2041916, (1980), Eur.484963 for document 2.; (1996)] introduced the method for low pressure depolymerization in, at 180-280 ℃, 2.0-6.0MPa carries out as the one of which; Depolymerization rate can be brought up to 3 hours; But the depolymerization flow process is complicated, generally need go on foot the circulation depolymerization through 2-3 and just can accomplish, and also has small amounts of oligomer and hydroxyl-ethyl terephthaldehyde ester in the product simultaneously.
Among the document 3. patent CN1304924, adopt methyl alcohol under super critical condition, temperature 245-300 ℃, pressure 8.5-11MPa depolymerization PET0.5-3.0 hour, but the step conversion of Rapid Realization polyester.
Summary of the invention
The object of the invention provides a kind of waste and old polyester depolymerization method, is in reaction system, to add methyl alcohol and cosolvent gas, and disaggregation of waste and old polyester under super critical condition obtains DMT. Dimethyl p-benzenedicarboxylate and terepthaloyl moietie.
The present invention is owing to introduce cosolvent gas, and make the critical condition of former system: temperature 245-300 ℃, pressure 8.5-11MPa is reduced between 220-280 ℃, and pressure makes reaction conditions become gentle at 8-20MPa; The depolymerization time shortened to 0.25-1 hour by 0.5-3.0 hour; Keep higher polyester degradation rate simultaneously.
The present invention mainly adopts following technical scheme:
A. polyethylene terephthalate is crushed to 10-50mm, cleans after drying to anhydrous; With polyester and methyl alcohol according to mass ratio 1: the 4-15 ratio adds and has in the high-temperature high-pressure reaction kettle of whipping appts; In reaction system, charge into gas (N
2, CO
2), to the still internal pressure be 0.5-6.0Pa, be warming up on the critical temperature and pressure of mixed system, promptly temperature is between 220-280 ℃, pressure depolymerization 0.25-1 hour, is reduced to room temperature, vent gas, discharging after depolymerization finishes between 8-20MPa;
B. the reaction product of steps A is filtered, liquid is the mixture of methyl alcohol and terepthaloyl moietie, and solid is used methanol wash, drying, and recrystallization obtains purified DMT. Dimethyl p-benzenedicarboxylate.
Main advantage of the present invention is:
1. cosolvent, methyl alcohol---the supercritical fluids system of cosolvent can reduce temperature of reaction owing to having added in the present invention, shortens the reaction times, can save energy consumption.The cosolvent cost that is adopted is lower, and is easy to reclaim.
2. present method polyethylene terephthalate degradation rate is greater than 99.9%, and monomer selectivity is high, and the content of oligopolymer is low in the product.
Embodiment
Through instance content of the present invention is carried out detailed explanation below.
Embodiment 1: get polyethylene terephthalate waste material 6.8g, put into and be furnished with magnetic stirrer, in the 200ml high-temperature high-pressure reaction kettle of thermopair and temperature programming controller, add methyl alcohol 68.74ml, charge into N
2Reach 0.5MPa to the still internal pressure, agitator is warming up to 240 ℃ with the speed of 5 ℃/min, and pressure rises to 8.9MPa, and agitator is reflected at and carried out under this temperature 20 minutes.Reaction finishes the nature cooling, with solid and liquid separation.Solid through the washing, methanol wash, drying is weighed as 6.32g, the monomers dimethyl terephthalate yield is 92.2%.Terepthaloyl moietie in the filtrating is analyzed with periodate method, records that terepthaloyl moietie content is 2.07g in the filtrating.The polyethylene terephthalate degradation rate is 94.3%.
Embodiment 2: get polyethylene terephthalate waste material 6.8g, put into one and be furnished with magnetic stirrer, in the 200ml high-temperature high-pressure reaction kettle of thermopair and temperature programming controller, add methyl alcohol 68.74ml, charge into N
2Reach 1MPa to the still internal pressure, be warming up to 250 ℃ with the speed of 5 ℃/min, pressure rises to 10.1MPa, and agitator is reflected at and carried out under this temperature 30 minutes.After reaction finishes cooling, with solid and liquid separation.Solid through the washing, methanol wash, drying is weighed as 6.53g, the monomers dimethyl terephthalate yield is 95.3%.Preparation Na
2S
2O
3Solution and Periodic acid 99 solution, the terepthaloyl moietie in the liquid is analyzed with periodate method, and terepthaloyl moietie content is 2.17g in the filtrating, and the polyethylene terephthalate degradation rate is 98.6%.
Embodiment 3: get polyethylene terephthalate waste material 6.8g, put into one and be furnished with magnetic stirrer, in the 200ml high-temperature high-pressure reaction kettle of thermopair and temperature programming controller, add methyl alcohol 52.5ml, charge into N
2Reach 2MPa to the still internal pressure, be warming up to 260 ℃ with the speed of 5 ℃/min, pressure rises to 9.8MPa, and agitator is reflected at and carried out under this temperature 30 minutes.After reaction finishes cooling, with solid and liquid separation.Solid through the washing, methanol wash, drying is weighed as 6.44g, the monomers dimethyl terephthalate yield is 93.7%.Preparation Na
2S
2O
3Solution and Periodic acid 99 solution, the terepthaloyl moietie in the liquid is analyzed with periodate method, and terepthaloyl moietie content is 2.15g in the filtrating, and the polyethylene terephthalate degradation rate is 97.9%.
Embodiment 4: get polyethylene terephthalate waste material 6.8g, put into one and be furnished with magnetic stirrer, in the 200ml high-temperature high-pressure reaction kettle of thermopair and temperature programming controller, add methyl alcohol 52.5ml, charge into N
2Reach 4MPa to the still internal pressure, be warming up to 260 ℃ with the speed of 5 ℃/min, pressure rises to 15.5MPa, and agitator is reflected at and carried out under this temperature 20 minutes.After reaction finishes cooling, with solid and liquid separation.Solid through the washing, methanol wash, drying is weighed as 6.60g, the monomers dimethyl terephthalate yield is 96.1%.Preparation Na
2S
2O
3Solution and Periodic acid 99 solution, the terepthaloyl moietie in the liquid is analyzed with periodate method, and terepthaloyl moietie content is 2.17g in the filtrating, and the polyethylene terephthalate degradation rate is 99.3%.
Embodiment 5: get polyethylene terephthalate waste material 6.8g, put into one and be furnished with magnetic stirrer, in the 200ml high-temperature high-pressure reaction kettle of thermopair and temperature programming controller, add methyl alcohol 68.74ml, charge into CO
2Reach 2MPa to the still internal pressure, be warming up to 240 ℃ with the speed of 5 ℃/min, pressure rises to 11.4MPa, and agitator is reflected at and carried out under this temperature 30 minutes.After reaction finishes cooling, with solid and liquid separation.Solid through the washing, methanol wash, drying is weighed as 6.56g, the monomers dimethyl terephthalate yield is 95.5%.Preparation Na
2S
2O
3Solution and Periodic acid 99 solution, the terepthaloyl moietie in the liquid is analyzed with periodate method, and terepthaloyl moietie content is 2.16g in the filtrating, and the polyethylene terephthalate degradation rate is 98.4%.
Embodiment 6: get polyethylene terephthalate waste material 6.8g, put into one and be furnished with magnetic stirrer, in the 200ml high-temperature high-pressure reaction kettle of thermopair and temperature programming controller, add methyl alcohol 68.74ml, charge into CO
2Reach 4MPa to the still internal pressure, be warming up to 240 ℃ with the speed of 5 ℃/min, pressure rises to 14.9MPa, and agitator is reflected at and carried out under this temperature 20 minutes.After reaction finishes cooling, with solid and liquid separation.Solid through the washing, methanol wash, drying is weighed as 6.61g, the monomers dimethyl terephthalate yield is 96.4%.Preparation Na
2S
2O
3Solution and Periodic acid 99 solution, the terepthaloyl moietie in the liquid is analyzed with periodate method, and terepthaloyl moietie content is 2.18g in the filtrating, and the polyethylene terephthalate degradation rate is 99.9%.
Embodiment 7: get polyethylene terephthalate waste material 6.8g, put into one and be furnished with magnetic stirrer, in the 200ml high-temperature high-pressure reaction kettle of thermopair and temperature programming controller, add methyl alcohol 68.74ml, charge into CO
2Reach 4MPa to the still internal pressure, be warming up to 240 ℃ with the speed of 5 ℃/min, pressure rises to 11.4MPa, and agitator is reflected at and carried out under this temperature 20 minutes.After reaction finishes cooling, with solid and liquid separation.Solid through the washing, methanol wash, drying is weighed as 6.56g, the monomers dimethyl terephthalate yield is 95.5%.Preparation Na
2S
2O
3Solution and Periodic acid 99 solution, the terepthaloyl moietie in the liquid is analyzed with periodate method, and terepthaloyl moietie content is 2.16g in the filtrating, and the polyethylene terephthalate degradation rate is 99.9%.
Claims (2)
1. the depolymerization method of a useless polyester, concrete steps are following:
A. polyethylene terephthalate is crushed to 10-50mm, cleans after drying to anhydrous; With polyester and methyl alcohol according to mass ratio 1: the 4-15 ratio adds and has in the high-temperature high-voltage reaction device of whipping appts, in reaction system, charges into cosolvent, to the still internal pressure be 0.5-6.0MPa; Be warming up on the critical temperature and pressure of mixed system, making temperature is 220-280 ℃, and pressure is 8-20MPa; The depolymerization time is 20-40 minute; Depolymerization is reduced to room temperature, vent gas, discharging after finishing;
Described cosolvent is N
2, CO
2, H
2, CH
4Or a kind of among the CO;
B. the reaction product of steps A is filtered, liquid is the mixture of methyl alcohol and terepthaloyl moietie, and solid is used methanol wash, drying, and recrystallization obtains purified DMT. Dimethyl p-benzenedicarboxylate.
2. the depolymerization method of useless polyester according to claim 1 is characterized in that depolymerization reaction is 220-260 ℃ in temperature, and pressure is under the 8-18MPa condition, depolymerization 20-30 minute; Described cosolvent is N
2Or CO
2
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009100813595A CN101565374B (en) | 2009-04-03 | 2009-04-03 | Method for depolymerizing waste polyester |
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|---|---|---|---|
| CN2009100813595A CN101565374B (en) | 2009-04-03 | 2009-04-03 | Method for depolymerizing waste polyester |
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| CN101565374A CN101565374A (en) | 2009-10-28 |
| CN101565374B true CN101565374B (en) | 2012-04-25 |
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| CN2009100813595A Expired - Fee Related CN101565374B (en) | 2009-04-03 | 2009-04-03 | Method for depolymerizing waste polyester |
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Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8541477B2 (en) * | 2011-03-04 | 2013-09-24 | International Business Machines Corporation | Methods of depolymerizing terephthalate polyesters |
| CN103360260B (en) * | 2012-04-10 | 2015-04-01 | 李晓峰 | Preparation technology of ethylene glycol terephthalate and preparation method of polyester |
| CN102675113A (en) * | 2012-06-08 | 2012-09-19 | 沈冬杰 | Method for preparing diglycol phthalate by performing alcoholysis on polyester (PET) |
| CN106866413A (en) * | 2017-01-11 | 2017-06-20 | 西安工业大学 | A kind of method that efficient cryogenic reclaims Waste Polyester PET |
| CN109060583B (en) * | 2018-08-13 | 2020-10-20 | 中国纺织科学研究院有限公司 | Method for testing content of inorganic functional powder in functional polyester |
| CN109060582B (en) * | 2018-08-13 | 2020-09-25 | 中国纺织科学研究院有限公司 | Method for testing pigment content in stock solution coloring polyester |
| CN109322002A (en) * | 2018-10-10 | 2019-02-12 | 无锡沛莱斯纺织有限公司 | A kind of biodegradable polyesters fabric and preparation method thereof |
| CN109943026B (en) * | 2019-02-12 | 2021-06-08 | 武汉博茗低碳产业股份有限公司 | Supercritical water degradation polyester gradient phase change heat storage material and preparation method thereof |
| TWI766511B (en) * | 2020-12-28 | 2022-06-01 | 財團法人工業技術研究院 | Method for decolorization of polyester fabric |
| CN114539614B (en) * | 2022-01-26 | 2023-09-26 | 福建省腾龙工业公司 | Alkyd resin depolymerizing agent and preparation method and use method thereof |
| CN114989011A (en) * | 2022-05-11 | 2022-09-02 | 沈阳工业大学 | Method for preparing diethyl terephthalate |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0662466A1 (en) * | 1994-01-11 | 1995-07-12 | MONTEFIBRE S.p.A. | Continuous process for the recovery of terephthalic acid from waste or used products of polyalkylene terephthalate polymers |
| CN1304924A (en) * | 2000-07-07 | 2001-07-25 | 中国科学院山西煤炭化学研究所 | Process for depolymerizing waste glycol tere-phthalate |
-
2009
- 2009-04-03 CN CN2009100813595A patent/CN101565374B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0662466A1 (en) * | 1994-01-11 | 1995-07-12 | MONTEFIBRE S.p.A. | Continuous process for the recovery of terephthalic acid from waste or used products of polyalkylene terephthalate polymers |
| CN1304924A (en) * | 2000-07-07 | 2001-07-25 | 中国科学院山西煤炭化学研究所 | Process for depolymerizing waste glycol tere-phthalate |
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