A method of polyethylene terephthalate aminolysis
By converting polyethylene terephthalate into terephthalic acid, terephthalic acid monoamide, and terephthalamide through catalytic ammonolysis, the problem of the difficulty in decomposing waste polyester plastics is solved, and efficient value-added utilization and environmentally friendly plastic recycling are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- DALIAN INSTITUTE OF CHEMICAL PHYSICS CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2024-11-28
- Publication Date
- 2026-05-29
AI Technical Summary
Waste polyester plastics are difficult to decompose in a short time, causing environmental pressure. Existing recycling methods are inefficient and cannot effectively enhance their value.
A catalytic ammonolysis method is used to mix polyethylene terephthalate with ammonia water under mild conditions. Catalysts such as sodium stannate and activated carbon are used to react the mixture in an inactive atmosphere to produce terephthalic acid, terephthalic acid monoamide, and terephthalamide, thus achieving efficient value-added utilization.
This method achieves efficient value-added utilization of polyester plastics, with a total yield of up to 99%. The generated amide compounds are environmentally friendly, providing a new way to efficiently value-added utilize waste plastics, reducing energy consumption, and supporting sustainable development.
Abstract
Description
Technical Field
[0001] This application relates to a method for ammonolysis of polyethylene terephthalate, which belongs to the field of plastic recycling. Background Technology
[0002] With the increasing prevalence of plastic products in daily life, the production of polyester plastics has also increased rapidly. How to handle the resulting waste polyester has gradually attracted attention. Although waste polyester does not directly pollute the environment, its high chemical stability means it cannot decompose naturally in a short time, putting significant pressure on the environment. To achieve sustainable development, recycling waste polyester has become a key research focus for researchers worldwide. Currently, waste polyester recycling methods mainly fall into two categories: physical recycling and chemical recycling. Based on different depolymerization pathways, chemical recycling methods can be further divided into hydrolysis, alcohol hydrolysis, ammonolysis, and other methods. Catalytic ammonolysis can introduce active functional groups into the polyester, achieving value-added processing of polyethylene terephthalate (PET). Improving depolymerization efficiency is a practical issue that current research should focus on. Summary of the Invention
[0003] To address the aforementioned problems, the purpose of this invention is to develop a method for the catalytic ammonolysis of polyethylene terephthalate (PET), which degrades PET and introduces amide functional groups under mild conditions. This method is of significant strategic importance for treating environmental pollution and enhancing the value of waste plastics.
[0004] According to one aspect of this application, a method for catalytic ammonolysis of polyethylene terephthalate is provided, characterized in that...
[0005] Includes the following steps:
[0006] The raw material containing polyethylene terephthalate is mixed with ammonia water and reacted with a catalyst in a closed container under an inactive gas atmosphere to obtain a product containing terephthalic acid, terephthalic acid monoamide, and terephthalamide.
[0007] The polyethylene terephthalate is selected from at least one of commercial polyethylene terephthalate, polyethylene terephthalate after processing waste mineral water bottles, and polyethylene terephthalate after processing waste packaging bags.
[0008] The catalyst is selected from at least one of sodium stannate, activated carbon, barium oxide, magnesium oxide, aluminum oxide, zinc oxide, calcium oxide, magnesium hydroxide, calcium hydroxide, magnesium aluminum hydrotalcite, and hydroxyapatite.
[0009] The particle size of the polyethylene terephthalate is less than 2 mm.
[0010] The solid-liquid ratio of the polyethylene terephthalate to ammonia is 0.01–0.05 g / ml.
[0011] The mass ratio of polyethylene terephthalate to catalyst is 2 to 5:1.
[0012] The inert gas atmosphere includes a nitrogen atmosphere and an inert gas atmosphere;
[0013] The pressure of the inactive gas atmosphere is 0.5–2 MPa.
[0014] The concentration of the ammonia solution is 10–30 wt%.
[0015] The reaction temperature is 80–200°C;
[0016] The reaction time is 2 to 24 hours.
[0017] The sealed container is a sealed high-pressure reactor, and the amount of polyethylene terephthalate processed in the sealed high-pressure reactor is 0.1 to 2.0 g.
[0018] The beneficial effects that this application can produce include:
[0019] This invention develops a catalytic ammonolysis method for polyethylene terephthalate (PET). Utilizing ammonia water as the ammonia source, nitrogen is introduced into the degradation products of PET. By adding a catalyst, highly efficient value-added utilization of PET is achieved, providing a new approach for the efficient value-added utilization of polyester plastic waste. The total yield of terephthalic acid, terephthalic acid monoamide, and terephthalamide can reach up to 99%. This method enables the value-added utilization of waste plastics and produces amide organic chemicals as byproducts, exhibiting environmental friendliness and high treatment efficiency. The method for preparing amide compounds from waste PET through ammonolysis provided by this invention has low energy consumption, providing important protection for the sustainable development of my country's environment and economy, and proposing a new pathway for the value-added utilization of PET. Detailed Implementation
[0020] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.
[0021] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.
[0022] The catalysts used in this application example, namely sodium stannate, activated carbon, barium oxide, magnesium oxide, aluminum oxide, zinc oxide, calcium oxide, magnesium hydroxide, calcium hydroxide, magnesium aluminum hydrotalcite, and hydroxyapatite, are commercial catalysts that have been calcined at 350°C and then used in the catalytic reaction.
[0023] After the reaction, the mixed solids of terephthalic acid, terephthalic acid monoamide, and terephthalamide were dissolved in dimethyl sulfoxide, and the liquid products were analyzed using a reversed C18 column of high performance liquid chromatography.
[0024] Example 1
[0025] Weigh 0.25 g of polyethylene terephthalate and 10 mL of ammonia water into a 50 mL high-pressure reactor, and simultaneously add 0.1 g of magnesium aluminum hydrotalcite catalyst. Seal the reactor, purge the air inside with nitrogen, and finally fill with 0.5 MPa nitrogen. Heat to 150 °C using electric heating while stirring magnetically at 1000 rpm, and react for 120 min. After the reaction is complete, stop stirring, place the reactor in an ice-water bath to cool for 30 min, purge the nitrogen gas, and then open the reactor. Place the product in an 80 °C oven to remove the ammonia water, dissolve the dried solid in DMSO solvent, and perform liquid chromatography analysis.
[0026] The yields obtained were: terephthalamide (22.3 wt%), terephthalic acid monoamide (56.2 wt%), and terephthalic acid (18.4 wt%).
[0027] Example 2
[0028] Weigh 0.25 g of polyethylene terephthalate and 10 mL of ammonia water into a 50 mL high-pressure reactor, and simultaneously add 0.1 g of magnesium aluminum hydrotalcite catalyst. Seal the reactor, purge the air inside with nitrogen, and finally fill with 0.5 MPa nitrogen. Heat to 150 °C using electric heating while stirring magnetically at 1000 rpm, and react for 240 min. After the reaction is complete, stop stirring, place the reactor in an ice-water bath to cool for 30 min, purge the nitrogen gas, and then open the reactor. Place the product in an 80 °C oven to remove the ammonia water, dissolve the resulting solid in DMSO solvent, and perform high-performance liquid chromatography (HPLC) analysis.
[0029] The yields obtained were: terephthalamide (15.8 wt%), terephthalic acid monoamide (60.3 wt%), and terephthalic acid (23.9 wt%).
[0030] Example 3
[0031] Weigh 0.25 g of polyethylene terephthalate and 10 mL of ammonia water into a 50 mL high-pressure reactor, and simultaneously add 0.1 g of hydroxyapatite catalyst. Seal the reactor, purge the air inside with nitrogen, and finally fill with 0.5 MPa nitrogen. Heat to 150 °C using electric heating while stirring magnetically at 1000 rpm, and react for 120 min. After the reaction is complete, stop stirring, place the reactor in an ice-water bath to cool for 30 min, purge the nitrogen gas, and then open the reactor. Place the product in an 80 °C oven to remove the ammonia water, dissolve the resulting solid in DMSO solvent, and perform high-performance liquid chromatography (HPLC) analysis.
[0032] The yields obtained were: terephthalamide (20.9 wt%), terephthalic acid monoamide (50.4 wt%), and terephthalic acid (14.7 wt%).
[0033] Example 4
[0034] Weigh 0.25 g of polyethylene terephthalate and 10 mL of ammonia water into a 50 mL high-pressure reactor, and simultaneously add 0.1 g of sodium stannate catalyst. Seal the reactor, purge the air inside with nitrogen, and finally fill with 0.5 MPa nitrogen. Heat to 150 °C using electric heating while stirring magnetically at 1000 rpm, and react for 120 min. After the reaction is complete, stop stirring, place the reactor in an ice-water bath to cool for 30 min, purge the nitrogen, and then open the reactor. Place the product in an 80 °C oven to remove the ammonia water, dissolve the resulting solid in DMSO solvent, and perform high-performance liquid chromatography (HPLC) analysis.
[0035] The yields obtained were: terephthalamide (10.3 wt%), terephthalic acid monoamide (32.7 wt%), and terephthalic acid (14.3 wt%).
[0036] Example 5
[0037] Weigh 0.25 g of polyethylene terephthalate and 10 mL of ammonia water into a 50 mL high-pressure reactor, and simultaneously add 0.1 g of calcium oxide catalyst. Seal the reactor, purge the air inside with nitrogen, and finally fill with 0.5 MPa nitrogen. Heat to 150 °C using electric heating while stirring magnetically at 1000 rpm, and react for 120 min. After the reaction is complete, stop stirring, place the reactor in an ice-water bath to cool for 30 min, purge the nitrogen gas, and then open the reactor. Place the product in an 80 °C oven to remove the ammonia water, dissolve the resulting solid in DMSO solvent, and perform high-performance liquid chromatography (HPLC) analysis.
[0038] The yields obtained were: terephthalamide (0.8 wt%), terephthalic acid monoamide (0.1 wt%), and terephthalic acid (1.7 wt%).
[0039] Example 6
[0040] Weigh 0.25 g of polyethylene terephthalate and 10 mL of ammonia water into a 50 mL high-pressure reactor, and simultaneously add 0.1 g of magnesium aluminum hydrotalcite catalyst. Seal the reactor, purge the air inside with nitrogen, and finally fill with 0.5 MPa nitrogen. Heat to 140 °C using electric heating while stirring magnetically at 1000 rpm, and react for 120 min. After the reaction is complete, stop stirring, place the reactor in an ice-water bath to cool for 30 min, purge the nitrogen gas, and then open the reactor. Place the product in an 80 °C oven to remove the ammonia water, dissolve the resulting solid in DMSO solvent, and perform high-performance liquid chromatography (HPLC) analysis.
[0041] The yields obtained were: terephthalamide (23.0 wt%), terephthalic acid monoamide (40.0 wt%), and terephthalic acid (12.3 wt%).
[0042] Example 7
[0043] Weigh 0.25 g of polyethylene terephthalate and 10 mL of ammonia water into a 50 mL high-pressure reactor, and simultaneously add 0.1 g of magnesium aluminum hydrotalcite catalyst. Seal the reactor, purge the air inside with nitrogen, and finally fill with 0.5 MPa nitrogen. Heat to 130 °C using electric heating while stirring magnetically at 1000 rpm, and react for 120 min. After the reaction is complete, stop stirring, place the reactor in an ice-water bath to cool for 30 min, purge the nitrogen gas, and then open the reactor. Place the product in an 80 °C oven to remove the ammonia water, dissolve the resulting solid in DMSO solvent, and perform high-performance liquid chromatography (HPLC) analysis.
[0044] The yields obtained were: terephthalamide (16.8 wt%), terephthalic acid monoamide (25.3 wt%), and terephthalic acid (7.2 wt%).
[0045] Example 8
[0046] Weigh 0.25 g of polyethylene terephthalate and 10 mL of ammonia water into a 50 mL high-pressure reactor, and simultaneously add 0.1 g of magnesium aluminum hydrotalcite catalyst. Seal the reactor, purge the air inside with nitrogen, and finally fill with 0.5 MPa nitrogen. Heat to 120°C using electric heating while stirring magnetically at 1000 rpm, and react for 120 min. After the reaction is complete, stop stirring, place the reactor in an ice-water bath to cool for 30 min, purge the nitrogen gas, and then open the reactor. Place the product in an 80°C oven to remove the ammonia water, dissolve the resulting solid in DMSO solvent, and perform high-performance liquid chromatography (HPLC) analysis.
[0047] The yields obtained were: terephthalamide (9.2 wt%), terephthalic acid monoamide (9.4 wt%), and terephthalic acid (1.8 wt%).
[0048] Example 9
[0049] Weigh 0.25 g of polyethylene terephthalate and 10 mL of ammonia water into a 50 mL high-pressure reactor, and simultaneously add 0.1 g of magnesium aluminum hydrotalcite catalyst. Seal the reactor, purge the air inside with nitrogen, and finally fill with 0.5 MPa nitrogen. Heat to 110 °C using electric heating while stirring magnetically at 1000 rpm, and react for 120 min. After the reaction is complete, stop stirring, place the reactor in an ice-water bath to cool for 30 min, purge the nitrogen gas, and then open the reactor. Place the product in an 80 °C oven to remove the ammonia water, dissolve the resulting solid in DMSO solvent, and perform high-performance liquid chromatography (HPLC) analysis.
[0050] The yields obtained were: terephthalamide (5.2 wt%), terephthalic acid monoamide (5.8 wt%), and terephthalic acid (1.1 wt%).
[0051] Example 10
[0052] Weigh 0.25 g of polyethylene terephthalate and 10 mL of ammonia water into a 50 mL high-pressure reactor, and simultaneously add 0.1 g of magnesium aluminum hydrotalcite catalyst. Seal the reactor, purge the air inside with nitrogen, and finally fill with 0.5 MPa nitrogen. Heat to 200 °C using electric heating while stirring magnetically at 1000 rpm, and react for 120 min. After the reaction is complete, stop stirring, place the reactor in an ice-water bath to cool for 30 min, purge the nitrogen gas, and then open the reactor. Place the product in an 80 °C oven to remove the ammonia water, dissolve the resulting solid in DMSO solvent, and perform high-performance liquid chromatography (HPLC) analysis.
[0053] The yields obtained were: terephthalamide (3.2 wt%), terephthalic acid monoamide (46.5 wt%), and terephthalic acid (50.3 wt%).
[0054] Example 11
[0055] Weigh 0.25 g of polyethylene terephthalate and 10 mL of ammonia water into a 50 mL high-pressure reactor, and simultaneously add 0.1 g of magnesium aluminum hydrotalcite catalyst. Seal the reactor, purge the air inside with nitrogen, and finally fill with 0.5 MPa nitrogen. Heat to 180°C using electric heating while stirring magnetically at 1000 rpm, and react for 120 min. After the reaction is complete, stop stirring, place the reactor in an ice-water bath to cool for 30 min, purge the nitrogen gas, and then open the reactor. Place the product in an 80°C oven to remove the ammonia water, dissolve the resulting solid in DMSO solvent, and perform high-performance liquid chromatography (HPLC) analysis.
[0056] The yields obtained were: terephthalamide (4.1 wt%), terephthalic acid monoamide (48.8 wt%), and terephthalic acid (47.0 wt%).
[0057] Example 12
[0058] Weigh 0.25 g of polyethylene terephthalate and 10 mL of ammonia water into a 50 mL high-pressure reactor, and simultaneously add 0.1 g of magnesium aluminum hydrotalcite catalyst. Seal the reactor, purge the air inside with nitrogen, and finally fill with 0.5 MPa nitrogen. Heat to 170 °C using electric heating while stirring magnetically at 1000 rpm, and react for 120 min. After the reaction is complete, stop stirring, place the reactor in an ice-water bath to cool for 30 min, purge the nitrogen gas, and then open the reactor. Place the product in an 80 °C oven to remove the ammonia water, dissolve the resulting solid in DMSO solvent, and perform high-performance liquid chromatography (HPLC) analysis.
[0059] The yields obtained were: terephthalamide (18.0 wt%), terephthalic acid monoamide (56.5 wt%), and terephthalic acid (21.7 wt%).
[0060] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.
Claims
1. A method for catalytic ammonolysis of polyethylene terephthalate, characterized in that, Includes the following steps: The raw material containing polyethylene terephthalate is mixed with ammonia water and reacted with a catalyst in a closed container under an inactive gas atmosphere to obtain a product containing terephthalic acid, terephthalic acid monoamide, and terephthalamide. The polyethylene terephthalate is selected from at least one of commercial polyethylene terephthalate, polyethylene terephthalate after processing waste mineral water bottles, and polyethylene terephthalate after processing waste packaging bags. The catalyst is selected from at least one of sodium stannate, activated carbon, barium oxide, magnesium oxide, aluminum oxide, zinc oxide, calcium oxide, magnesium hydroxide, calcium hydroxide, magnesium aluminum hydrotalcite, and hydroxyapatite.
2. The method according to claim 1, characterized in that, The particle size of the polyethylene terephthalate is less than 2 mm.
3. The method according to claim 1, characterized in that, The solid-liquid ratio of the polyethylene terephthalate to ammonia is 0.01–0.05 g / ml.
4. The method according to claim 1, characterized in that, The mass ratio of polyethylene terephthalate to catalyst is 2 to 5:
1.
5. The method according to claim 1, characterized in that, The inert gas atmosphere includes a nitrogen atmosphere and an inert gas atmosphere; The pressure of the inactive gas atmosphere is 0.5–2 MPa.
6. The method according to claim 1, characterized in that, The concentration of the ammonia solution is 10–30 wt%.
7. The method according to claim 1, characterized in that, The reaction temperature is 80–200°C; The reaction time is 2 to 24 hours.