High-valued recycling method of polycarbonate waste

Abstract

Belonging to the technical field of solid waste recycling, the invention discloses a polycarbonate waste high-valued recycling method, which comprises the following steps: utilizing crushed bisphenol A polycarbonate waste, o-phenylenediamine compounds and an ionic liquid catalyst to construct a reaction system, placing the reaction system at the temperature of 100-150 DEG C in an air atmosphere, and carrying out a reaction for more than or equal to 30 min to obtain the product bisphenol A and benzimidazolone compounds; according to the method, two monomers including bisphenol A and benzimidazolone compounds are recycled at the same time, the one-step method is high in reaction efficiency, the reaction can be carried out under normal pressure and solvent-free conditions, carbon resources in polycarbonate waste can be fully utilized, and the method has wide application prospects in the aspect of waste plastic recycling.

Description

Technical Field

[0001] The invention belongs to the technical field of solid waste recycling, and in particular relates to a high-value recycling method for polycarbonate waste. Background Art

[0002] Polycarbonate is a non-crystalline thermoplastic with excellent physical, chemical and processing properties, such as high strength, impact resistance, chemical corrosion resistance, high transparency, etc. It occupies an important position in the engineering plastics market. Polycarbonate can be used to manufacture food and beverage containers, protective equipment, industrial safety baffles, insulating connectors, electrical housings, etc. It has a wide range of applications in optical instruments, automotive industry, construction industry, electronic products, medical field, packaging industry, aerospace and other fields. However, with the mass production and use of polycarbonate products, the problem of post-waste disposal has become increasingly urgent. If untreated polycarbonate waste directly enters the environment, it will pollute the soil and water and affect the ecological environment. Therefore, it is necessary to develop a high-value recycling strategy for polycarbonate waste to achieve resource reuse and reduce the risk of ecological environmental pollution.

[0003] Researchers have developed a variety of strategies for recycling polycarbonate, such as the hydrolysis process, alcoholysis process, glycolysis process, and pyrolysis process of polycarbonate, to convert polycarbonate into high-value-added chemical monomers. For example, the publication numbers CN111484395A and CN106748665A disclose the methanol alcoholysis method of polycarbonate. The corresponding method is green and mild, and the CO bond is broken by attacking the carbonate bond (-OC(=O)-O-) with methanol, ethanol, etc. to obtain the monomer bisphenol A. The publication numbers CN117986094A and CN118791367A disclose the use of alkylating agents (such as dimethyl carbonate) as methyl sources and the use of specific catalysts to achieve the conversion of polycarbonate into monomers such as bisphenol A dimethyl ether. The above reactions usually only produce a single chemical monomer, and the full and effective utilization of carbon resources is not achieved.

[0004] Benzimidazolone is a derivative of benzimidazole. Due to its unique structural feature - the combination of benzimidazole ring system and carbonyl group, this kind of compound has high stability and a wide range of biological activities (such as antibacterial, anticancer and anti-inflammatory effects), which is of great significance in medicinal chemistry. In addition to its pharmacological importance, benzimidazolone-based heterocyclic compounds also have good application prospects in fields such as materials science and catalysis. In the prior art, there is no report on the synthesis of benzimidazolone and its derivatives using waste polycarbonate. Summary of the invention

[0005] The invention provides a high-value recycling method for polycarbonate waste. By introducing o-phenylenediamine or its derivatives, the recovery of two monomers, bisphenol A and benzimidazolone compounds, is achieved. The reaction can be carried out under normal pressure and solvent-free conditions, and two chemical monomers can be prepared in one-step reaction, which can fully utilize the carbon resources in the polycarbonate waste.

[0006] The specific technical solutions adopted are as follows: A high-value recycling method for polycarbonate waste comprises the following steps: A reaction system is constructed by using crushed bisphenol A type polycarbonate waste, o-phenylenediamine compounds and ionic liquid catalysts, and the reaction system is placed at a temperature of 100 to 150° C. in an air atmosphere for a reaction of ≥30 min to obtain bisphenol A and benzimidazolone compounds; The structural formula of the o-phenylenediamine compound is as follows; wherein R1 and R2 are each independently selected from hydrogen, methyl, methoxy or halogen; ; The structural formula of the ionic liquid catalyst is: .

[0007] The present invention selects a specific ionic liquid catalyst to construct a reaction system comprising bisphenol A type polycarbonate waste, o-phenylenediamine compounds and the ionic liquid catalyst. No organic solvent is added, and the polycarbonate can be fully depolymerized by reacting under air atmosphere and normal pressure. At the same time, benzimidazolone compounds are prepared, and the upgraded conversion of bisphenol A type polycarbonate waste into two high value-added chemical monomers is realized in one step.

[0008] Preferably, bisphenol A type polycarbonate waste includes but is not limited to PC material plates, sheets, tubes, films, etc., and of course pure polycarbonate can also be used. The method of the present invention is suitable for the recycling and upgrading of various forms of bisphenol A type polycarbonate waste, showing excellent efficiency and adaptability.

[0009] Preferably, the o-phenylenediamine compound is at least one of the following compounds: .

[0010] Different o-phenylenediamine compounds can be used to obtain different benzimidazolone or its derivatives, wherein the benzimidazolone compound is at least one of the following compounds: .

[0011] Optionally, the reaction system further comprises water, and the ratio of water to bisphenol A polycarbonate waste is 0.01-0.05 g:1 mmol. The method of the present invention can be successfully carried out in the absence of solvent or in the presence of a trace amount of water.

[0012] Preferably, the molar ratio of the bisphenol A type polycarbonate waste to the o-phenylenediamine compound is 1:1-5.

[0013] Preferably, the molar ratio of the bisphenol A polycarbonate waste to the ionic liquid catalyst is 1:0.06-0.50.

[0014] Most preferably, the molar ratio of the bisphenol A polycarbonate waste to the o-phenylenediamine compound is 1:1-3, and the molar ratio of the bisphenol A polycarbonate waste to the ionic liquid catalyst is 1:0.20-0.50. Under the above conditions and parameters, the product bisphenol A and benzimidazolone compounds can be prepared in high yield, which helps the ionic liquid catalyst to play a role in achieving full conversion of the raw materials and effectively utilize the carbon resources in the bisphenol A polycarbonate.

[0015] Preferably, the reaction conditions are a temperature of 110 to 130° C. and a time of 0.5 to 6 h.

[0016] The yield of bisphenol A obtained by the high-value recycling method of polycarbonate waste is ≥56%, preferably ≥89%, and most preferably ≥99%; the yield of benzimidazolone compounds is ≥65%, preferably ≥75%, and most preferably ≥95%.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention constructs a specific reaction system to develop a method for recycling polycarbonate waste, which is carried out under air atmosphere, normal pressure, and in the absence of solvent (or in the presence of a trace amount of water). The reaction conditions are simple and mild, the reaction speed is fast, and the types of raw materials are few. The carbon resources in bisphenol A type polycarbonate can be fully utilized, turning waste into treasure, being green and environmentally friendly, and realizing the dual upgrading and transformation of waste plastic resources. Two chemical monomers, bisphenol A and benzimidazolone compounds, are simultaneously prepared in one step, and bisphenol A and benzimidazolone compounds are easy to separate. The two reaction products can be further used to synthesize functional chemical substances.

[0018] (2) The method of the present invention can further expand the reaction products and is not limited to benzimidazolone. Various benzimidazolone derivatives can also be prepared. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a reaction route for high-value recycling of polycarbonate waste in Example 1.

[0020] Figure 2 This is the H NMR spectrum of the product bisphenol A (deuterated chloroform).

[0021] Figure 3 This is the H NMR spectrum of the product benzimidazolone (deuterated chloroform). DETAILED DESCRIPTION

[0022] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the following is a detailed description through specific embodiments. In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below. The technical features in each embodiment of the present invention can be combined accordingly without conflicting with each other.

[0023] The operating methods in the following examples without specifying specific conditions are usually carried out under conventional conditions or according to the conditions recommended by the manufacturer. The contents not described in detail in this specification belong to the prior art known to professionals in the field. The experimental materials used in the following examples, unless otherwise specified, can be purchased from conventional biochemical reagent companies.

[0024] The reaction processes of the following examples and comparative examples were all carried out under normal pressure, which generally refers to 0.09-0.11 MPa, without applying additional pressure; the structural formula of the ionic liquid catalyst used is: , can be synthesized according to literature records; polycarbonates are all bisphenol A type polycarbonates.

[0025] Comparative Example 1 In a pressure tube reactor equipped with an electromagnetic stirrer, a thermocouple, and a programmable temperature controller, 0.254 g of CR-pure polycarbonate powder (1 mmol), 2 mmol of o-phenylenediamine, 0.4 mmol of 1,8-diazabicyclo[5.4.0]undec-7-ene, 0.02 g of water, and 2 mL of N -Methylpyrrolidone, after placing the pressure tube reactor, start stirring and heating. The reaction system is heated to 130°C and reacted at this temperature for 4 hours. After the reaction is completed, it is cooled to room temperature, and the resulting mixed solution is the product. Take 50 µL of the resulting mixed solution, add 600 µL of deuterated DMSO, and measure the yield by nuclear magnetic resonance spectrometer. The results show that the yield of bisphenol A is 99% and the yield of benzimidazolone is 48%.

[0026] Comparative Example 2 In a pressure tube reactor equipped with an electromagnetic stirrer, a thermocouple, and a programmable temperature controller, 0.254 g of CR-pure polycarbonate powder (1 mmol), 2 mmol of o-phenylenediamine, 0.4 mmol of ionic liquid catalyst, and 2 mL N -Methylpyrrolidone, after placing the pressure tube reactor, start stirring and heating. The reaction system is heated to 130°C and reacted at this temperature for 4 hours. After the reaction is completed, it is cooled to room temperature, and the resulting mixed solution is the product. Take 50 µL of the resulting mixed solution, add 600 µL of deuterated DMSO, and measure the yield by nuclear magnetic resonance spectrometer. The results show that the yield of bisphenol A is 99% and the yield of benzimidazolone is 59%.

[0027] Example 1 0.254 g of CR-purity polycarbonate powder (1 mmol), 2 mmol of o-phenylenediamine, and 0.2 mmol of ionic liquid catalyst were added to a pressure tube reactor equipped with an electromagnetic stirrer, a thermocouple, and a programmable temperature controller. After the pressure tube reactor was placed, stirring and heating were started. The reaction system was heated to 130°C and reacted at this temperature for 4 hours. After the reaction was completed, the temperature was cooled to room temperature, and the resulting mixed solution was the product, which could be further separated by post-treatment methods including column chromatography to obtain bisphenol A and benzimidazolone. 2 mL of dimethyl sulfoxide was added to the mixed solution, mixed evenly, 50 µL was taken, and 600 µL of deuterated DMSO was added. The yield was determined by nuclear magnetic resonance spectrometer. The results showed that the yield of bisphenol A was 99% and the yield of benzimidazolone was 95%.

[0028] The specific reaction route is as follows Figure 1 As shown, the H NMR spectrum of the product bisphenol A is as follows Figure 2 As shown, the H NMR spectrum of the product benzimidazolone is as follows Figure 3 As shown, it can be seen that the method of the present invention is successfully carried out.

[0029] Example 2 In a pressure tube reactor equipped with an electromagnetic stirrer, a thermocouple, and a programmable temperature controller, 0.254 g of CR-purity polycarbonate powder (1 mmol), 2 mmol of o-phenylenediamine, 0.4 mmol of ionic liquid catalyst, and different masses of water (0.05 g, 0.02 g, 0.01 g) were added. After the pressure tube reactor was placed, stirring and heating were turned on. The reaction system was heated to 130°C and reacted at this temperature for 4 hours. After the reaction was completed, the temperature was cooled to room temperature, and the resulting mixed solution was the product. 2 mL of dimethyl sulfoxide was added to the mixed solution, mixed evenly, 50 µL was taken, and 600 µL of deuterated DMSO was added. The yield was determined by nuclear magnetic resonance spectrometer. The results showed that the yields of bisphenol A were 99%, 99%, and 99%, respectively, and the yields of benzimidazolone were 99%, 90%, and 91%, respectively.

[0030] Example 3 In a pressure tube reactor equipped with an electromagnetic stirrer, a thermocouple, and a programmable temperature controller, 0.254 g of CR-purity polycarbonate powder (1 mmol), 2 mmol of o-phenylenediamine, and different moles of ionic liquid catalysts (0.06 mmol, 0.12 mmol, 0.20 mmol, 0.30 mmol, 0.40 mmol, and 0.50 mmol) were added. After the pressure tube reactor was placed, stirring and heating were turned on. The reaction system was heated to 130°C and reacted at this temperature for 4 hours. After the reaction was completed, the temperature was cooled to room temperature, and the resulting mixed solution was the product. 2 mL of dimethyl sulfoxide was added to the mixed solution, mixed evenly, 50 µL was taken, and 600 µL of deuterated DMSO was added. The yield was determined by nuclear magnetic resonance spectrometer. The results showed that the yields of bisphenol A were 56%, 70%, 99%, 99%, 99%, and 99%, respectively, and the yields of benzimidazolone were 55%, 70%, 95%, 95%, 95%, and 99%, respectively.

[0031] Example 4 0.254 g of CR-purity polycarbonate powder (1 mmol), 2 mmol of o-phenylenediamine, and 0.2 mmol of ionic liquid catalyst were added to a pressure tube reactor equipped with an electromagnetic stirrer, a thermocouple, and a programmable temperature controller. After the pressure tube reactor was placed, stirring and heating were turned on. The reaction system was heated to 130°C and reacted at this temperature for 0.5, 1, 2, 2.5, 3, 4, 5, and 6 hours, respectively. After the reaction was completed, the temperature was cooled to room temperature, and the resulting mixed solution was the product. 2 mL of dimethyl sulfoxide was added to the mixed solution, mixed evenly, 50 µL was taken, and 600 µL of deuterated DMSO was added. The yield was determined by nuclear magnetic resonance spectrometer. The results showed that the yields of bisphenol A were 89%, 91%, 93%, 99%, 99%, 99%, 99%, 99%, and 99%, respectively, and the yields of benzimidazolone were 75%, 77%, 78%, 85%, 85%, 95%, 94%, and 94%, respectively.

[0032] Example 5 In a pressure tube reactor equipped with an electromagnetic stirrer, a thermocouple, and a programmable temperature controller, 0.254 g of CR-pure polycarbonate powder (1 mmol), different moles of o-phenylenediamine (1 mmol, 1.5 mmol, 2 mmol, 3 mmol), and 0.2 mmol of ionic liquid catalyst were added. After the pressure tube reactor was placed, stirring and heating were turned on. The reaction system was heated to 130°C and reacted at this temperature for 4 hours. After the reaction was completed, the temperature was cooled to room temperature, and the resulting mixed solution was the product. 50 µL of the resulting mixed solution was taken, and 600 µL of deuterated DMSO was added. The yield was determined by nuclear magnetic resonance spectrometer. The results showed that the yields of bisphenol A were 72%, 99%, 99%, and 99%, respectively, and the yields of benzimidazolone were 65%, 92%, 95%, and 96%, respectively.

[0033] Example 6 In a pressure tube reactor equipped with an electromagnetic stirrer, a thermocouple, and a programmable temperature controller, different 0.254 g of polycarbonate waste (sunboard, PC lamp, transparent board, CD, waterproof wiring board, bucket) (about 1 mmol), 2 mmol of o-phenylenediamine, and 0.2 mmol of ionic liquid catalyst were added. After the pressure tube reactor was placed, stirring and heating were turned on. The reaction system was heated to 130 ° C and reacted at this temperature for 4 hours. After the reaction was completed, the temperature was cooled to room temperature, and the resulting mixed solution was the product. 2 mL of dimethyl sulfoxide was added to the mixed solution, mixed evenly, 50 µL was taken, and 600 µL of deuterated DMSO was added. The yield was determined by nuclear magnetic resonance spectrometer. The results showed that the yields of bisphenol A were 98%, 99%, 93%, 99%, 98%, and 99%, respectively, and the yields of benzimidazolone were 77%, 85%, 71%, 97%, 87%, and 99%, respectively.

[0034] Example 7 In a pressure tube reactor equipped with an electromagnetic stirrer, a thermocouple, and a programmable temperature controller, 0.254 g of CR-pure polycarbonate powder (1 mmol), 2 mmol of different o-phenylenediamine compounds ( ; ; ; ), 0.2 mmol ionic liquid catalyst, place the pressure tube reactor, start stirring and heating. The reaction system was heated to 130°C and reacted at this temperature for 4 hours. After the reaction was completed, it was cooled to room temperature, and the resulting mixed solution was the product. 2 mL of dimethyl sulfoxide was added to the mixed solution, mixed evenly, 50 µL was taken, and then 600 µL of deuterated DMSO was added. The yield was determined by nuclear magnetic resonance spectrometer. The results showed that the yields of bisphenol A were 99%, 99%, 99%, 99%, and the yields of benzimidazolone were 96%, 90%, 91%, and 92%.

[0035] Example 8 0.254 g of CR-purity polycarbonate powder (1 mmol), 2 mmol of o-phenylenediamine, and 0.2 mmol of ionic liquid catalyst were added to a pressure tube reactor equipped with an electromagnetic stirrer, a thermocouple, and a programmable temperature controller. After the pressure tube reactor was placed, stirring and heating were turned on. The reaction system was heated to 110°C, 120°C, 130°C, 140°C, and 150°C, respectively, and reacted at this temperature for 4 hours. After the reaction was completed, the temperature was cooled to room temperature, and the resulting mixed solution was the product. 2 mL of dimethyl sulfoxide was added to the mixed solution and mixed evenly. 50 µL of the mixed solution was taken, and 600 µL of deuterated DMSO was added. The yield was determined by nuclear magnetic resonance spectrometer. The results showed that the yields of bisphenol A were 95%, 96%, 99%, 89%, and 77%, respectively, and the yields of benzimidazolone were 83%, 83%, 95%, 74%, and 68%, respectively.

[0036] The embodiments described above provide a detailed description of the technical solutions of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements or similar substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for high-value recycling of polycarbonate waste, characterized in that: The following steps are involved: A reaction system is constructed by using crushed bisphenol A type polycarbonate waste, o-phenylenediamine compounds and ionic liquid catalysts, and the reaction system is placed at a temperature of 100 to 150° C. in an air atmosphere for a reaction of ≥30 min to obtain bisphenol A and benzimidazolone compounds; The structural formula of the o-phenylenediamine compound is as follows; wherein R1 and R2 are each independently selected from hydrogen, methyl, methoxy or halogen; ； The structural formula of the ionic liquid catalyst is: 。 2. The high-value recycling method for polycarbonate waste according to claim 1, characterized in that: Bisphenol A polycarbonate waste includes plates, sheets, tubes or films.

3. The high-value recycling method for polycarbonate waste according to claim 1, characterized in that: The o-phenylenediamine compound is at least one of the following compounds: 。 4. The high-value recycling method for polycarbonate waste according to claim 3, characterized in that: The benzimidazolone compound is at least one of the following compounds: 。 5. The high-value recycling method for polycarbonate waste according to claim 1, characterized in that: The reaction system also includes water, and the ratio of the water feeding amount to the bisphenol A type polycarbonate waste material is 0.01-0.05 g:1 mmol.

6. The high-value recycling method for polycarbonate waste according to claim 1, characterized in that: The molar ratio of bisphenol A type polycarbonate waste to o-phenylenediamine compounds is 1:1-5.

7. The high-value recycling method for polycarbonate waste according to claim 1, characterized in that: The molar ratio of bisphenol A type polycarbonate waste to the ionic liquid catalyst is 1:0.06-0.

50.

8. The high-value recycling method for polycarbonate waste according to claim 1, characterized in that: The molar ratio of bisphenol A type polycarbonate waste to o-phenylenediamine compounds is 1:1-3, and the molar ratio of bisphenol A type polycarbonate waste to ionic liquid catalyst is 1:0.20-0.

50.

9. The high-value recycling method for polycarbonate waste according to claim 1, characterized in that: The reaction conditions are temperature 110-130°C and time 0.5-6 h.

10. The high-value recycling method for polycarbonate waste according to claim 1, characterized in that: The yield of bisphenol A is ≥56%, and the yield of benzimidazolone compounds is ≥65%.

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