A method for preparing bisphenol A and heterocyclic compounds by using waste PC

Abstract

The present invention discloses a method for preparing bisphenol A and heterocyclic compounds from waste PC, belonging to the technical field of solid waste recycling. The present invention constructs a reaction system by using crushed waste PC, aminobenzonitrile compounds, base catalysts and solvents. Under an air atmosphere, the reaction system is placed at a temperature of 100-160 °C for a reaction of ≥30 min to obtain the products bisphenol A and heterocyclic compounds. The heterocyclic compounds are quinazoline-2,4(1H,3H)-dione or its derivatives; the aminobenzonitrile compounds include 2-aminobenzonitrile, 2-amino-5-fluorobenzonitrile, 2-amino-4-chlorobenzonitrile, etc.; the solvents include water and organic solvents. The method of the present invention can achieve the dual upgrading transformation of waste PC, and can simultaneously obtain the reaction products bisphenol A and quinazoline-2,4(1H,3H)-dione compounds. Moreover, the reaction conditions are mild and the reaction rate is fast, having broad application prospects in the high-value utilization of waste PC.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid waste recycling, and particularly relates to a method for preparing bisphenol A and heterocyclic compounds from waste PC. Background Art

[0002] Polycarbonate (PC) is an important thermoplastic engineering plastic, which has excellent physical and mechanical properties, chemical resistance, heat resistance and low temperature resistance, and is widely used in optical instruments, automotive industry, construction industry, electronic products, medical field, packaging industry, aerospace and other fields. Recycling of waste PC not only benefits environmental protection, reduces the pollution risk of soil and water bodies, but also realizes resource reuse, has high economic benefits, and can promote technological innovation and industrial upgrading. At present, waste PC is mainly recycled by mechanical treatment. However, with the increase in the number of recycling times, the product quality and performance gradually decline, resulting in this method becoming a downgraded recycling. In contrast, chemical upgrading recycling of waste PC can convert it into high-value-added chemical monomers, with higher economic benefits. Hydrolysis reaction, alcoholysis reaction, glycolysis reaction, pyrolysis reaction, etc. of waste PC are all key processes for realizing the chemical recycling of waste polycarbonate materials. However, the above reactions usually only obtain a single chemical monomer, and the full and effective utilization of carbon resources has not been achieved.

[0003] Heterocyclic compounds are organic compounds containing heterocyclic structures in their molecules and are commonly present in the structures of drug molecules. Quinazoline-2,4(1H,3H)-dione and its derivatives are an important class of heterocyclic compounds and have been widely used in the pharmaceutical and biotechnology industries. Quinazoline-2,4(1H,3H)-dione is an important intermediate in the pharmaceutical industry and is the core structure for synthesizing zenarestat, thioperamide, alfuzosin, prazosin, terazosin and doxazosin. The corresponding product drugs can be used to treat diseases such as diabetes, kidney disease, heart disease, hypertension, etc. In addition, 6,7-dimethoxyquinazoline-2,4(1H,3H)-dione derivatives are the drug source bodies for synthesizing α1-adrenergic receptor antagonists and are used for anti-hypertension. At present, there are various methods for synthesizing quinazoline-2,4(1H,3H)-dione and its derivatives. For example, Chinese patent document with publication number CN108863952A discloses a method using CO 2A method for synthesizing 2,4(1H,3H)-quinazolinedione and its derivatives using aminobenzyl nitrile compounds as raw materials and brine as a catalyst; Chinese patent document with publication number CN106946800A discloses a method for preparing quinazoline-2,4(1H,3H)-dione and its derivatives by carboxyl cyclization reaction using o-aminobenzonitrile or its derivatives substituted at the 4th and 5th positions as substrates and aqueous diethanolamine solution as a catalyst under a carbon dioxide atmosphere; however, the above methods all need to be carried out under a pressure condition of 0.5-2 MPa, and the reaction needs to be pressurized, and the reaction is not conducive to occurring under normal pressure.

[0004] In the prior art, a variety of methods for recycling bisphenol A from waste PC have been reported, such as Chinese patent documents with publication numbers CN118164826A and CN108607604A, etc., but there is no report on upgrading waste PC to bisphenol A and quinazoline-2,4(1H,3H)-dione and its derivatives at the same time. And as described above, the current methods for synthesizing quinazoline-2,4(1H,3H)-dione and its derivatives usually need to be carried out under pressurized conditions, and there are few reactions under normal pressure conditions. Summary of the Invention

[0005] In view of the high-value utilization demand of waste PC plastics and the problems existing in the synthesis process of quinazoline-2,4(1H,3H)-dione and its derivatives, the present invention provides a method for preparing bisphenol A and quinazoline-2,4(1H,3H)-dione and its derivatives from waste PC participated by 2-aminobenzonitrile. The reaction can be carried out under normal pressure, and the reaction rate is fast, realizing the full utilization of carbon resources in waste PC plastics.

[0006] The specific technical solutions adopted are as follows:

[0007] A method for preparing bisphenol A and heterocyclic compounds from waste PC, comprising the following steps:

[0008] Construct a reaction system using crushed waste polycarbonate PC plastics (bisphenol A type polycarbonate), aminobenzyl nitrile compounds, a base catalyst, and a solvent. Under an air atmosphere, place the reaction system at a temperature of 100-160 °C for a reaction of ≥30 min to obtain the products bisphenol A and heterocyclic compounds, and the heterocyclic compounds are quinazoline-2,4(1H,3H)-dione or its derivatives;

[0009] The aminobenzyl nitrile compounds include 2-aminobenzonitrile, 2-amino-5-fluorobenzonitrile, 2-amino-4-chlorobenzonitrile, 2-amino-5-chlorobenzonitrile, 2-amino-5-bromobenzonitrile, 2-amino-4-methylbenzene nitrile, 2-amino-5-methylbenzene nitrile, or 2-amino-4,5-dimethoxybenzene nitrile;

[0010] The base catalyst is an inorganic base or an organic base;

[0011] The solvent includes water and an organic solvent.

[0012] As an economical and green reaction path, the method of the present invention uses waste PC as a CO 2 source for the synchronous high-value reaction of aminobenzonitrile compounds, which can solve the problems of incomplete hydrolysis and low efficiency of PC, and by using the reaction process of the present invention, bisphenol A and quinazoline-2,4(1H,3H)-dione or its derivatives can be simultaneously prepared, realizing the upgrading transformation of waste PC into two high-value chemical monomers in one step, and effectively and fully utilizing carbon resources.

[0013] Optionally, the organic base includes 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), 4-dimethylaminopyridine (DMAP), 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTBD), 1,4-diazabicyclo[2.2.2]octane (DABCO), triethylenediamine (TEDA) or N,N diisopropylethylamine (DIPEA); the inorganic base includes sodium hydroxide, potassium hydroxide, cesium hydroxide, potassium carbonate or cesium carbonate. The base catalyst is further preferably DBU, TBD, cesium hydroxide or cesium carbonate. It has been experimentally proven that the catalytic activities of the above four base catalysts are higher.

[0014] Optionally, the organic solvent is N N-methylpyrrolidone, N,N N,N-dimethylformamide or N,N N,N-dimethylacetamide, and further preferably N N-methylpyrrolidone. In the solvent, the mass ratio of water to the organic solvent is 0.0005-0.15:1. When water is not added, the yield of quinazoline-2,4(1H,3H)-dione compounds will be affected. The combination of water and the organic solvent helps the reaction raw materials and the catalyst to play their roles, enabling the full and effective conversion of carbon resources in waste PC.

[0015] Preferably, the molar ratio of the aminobenzonitrile compound to waste PC is 0.5-3:1, and further 1.2-3:1; based on the molar number of the aminobenzonitrile compound being 100%, the molar number of the base catalyst added is 1%-50%, and further 7%-50% (mol / mol).

[0016] Preferably, the ratio of the solvent to the waste PC is 1 - 5 mL:1 mmol, and further preferably 2 - 2.5 mL:1 mmol.

[0017] Preferably, the reaction time is 30 min - 12 h, and further preferably 1 - 6 h.

[0018] The waste PC can be pure PC or PC - based waste, including waste PC optical discs, waste PC buckets, waste PC films, waste PC bottle materials, waste PC plates, waste PC sheets, waste PC lamp tubes, etc. The method of the present invention is applicable to various forms of waste PC samples, and the recovery rate of quinazoline - 2,4(1H,3H) - dione or its derivatives can be as high as 93%, showing excellent efficiency and adaptability.

[0019] When the waste PC is upgraded and transformed, it needs to be pre - crushed into centimeter - sized flakes, granules or powders to ensure the resource utilization effect of the waste PC, and to obtain bisphenol A and quinazoline - 2,4(1H,3H) - dione or its derivatives with high yield through directional upgrading.

[0020] Specifically, the product heterocyclic compounds include quinazoline - 2,4(1H,3H) - dione, 6 - fluoroquinazoline - 2,4(1H,3H) - dione, 7 - chloroquinazoline - 2,4(1H,3H) - dione, 6 - chloroquinazoline - 2,4(1H,3H) - dione, 6 - bromoquinazoline - 2,4(1H,3H) - dione, 6 - methylquinazoline - 2,4(1H,3H) - dione, 7 - methylquinazoline - 2,4(1H,3H) - dione or 6,7 - dimethoxyquinazoline - 2,4(1H,3H) - dione, etc. The method of the present invention can prepare various types of quinazoline - 2,4(1H,3H) - dione compounds, and the functional functional groups contained in the quinazoline - 2,4(1H,3H) - dione compounds are useful for their further upgrading and transformation.

[0021] Specifically, the method of the present invention can be carried out under normal pressure without additional pressure. Normal pressure generally refers to 0.09 - 0.11 MPa, which greatly reduces the reaction pressure compared with the existing methods for synthesizing quinazoline - 2,4(1H,3H) - dione or its derivatives.

[0022] Specifically, under standard reaction conditions, 0.254 g of PC (1 mmol), 0.236 g of 2 - aminobenzonitrile (2 mmol), 0.0608 g of DBU (0.4 mmol), 0.02 g of water and N N - methylpyrrolidone (2 mL) are reacted at 130 °C for 4 hours. The obtained products are bisphenol A and quinazoline - 2,4(1H,3H) - dione, and the yield of quinazoline - 2,4(1H,3H) - dione is 95%, and the yield of bisphenol A is 99%.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] (1) Compared with other methods for synthesizing quinazoline-2,4(1H,3H)-dione compounds, the reaction conditions of the present invention are simpler and milder, and the reaction rate is faster. In the prior art, the representative method for synthesizing quinazoline-2,4(1H,3H)-dione requires CO 2 at high temperature and high pressure or an expensive catalyst to achieve a 99% yield. However, the method of the present invention only needs to add 20% mol / mol (calculated based on 100% of the molar amount of aminobenzonitrile compounds) of DBU catalyst, and at 130 °C and normal pressure, a 95% yield can be achieved in only 4 hours.

[0025] (2) The method of the present invention can achieve further expansion of reaction products, not only limited to quinazoline-2,4(1H,3H)-dione, but also can prepare various products including 6-fluoroquinazoline-2,4(1H,3H)-dione, 7-chloroquinazoline-2,4(1H,3H)-dione, 6-chloroquinazoline-2,4(1H,3H)-dione, 6-bromoquinazoline-2,4(1H,3H)-dione, 6-methylquinazoline-2,4(1H,3H)-dione, 7-methylquinazoline-2,4(1H,3H)-dione, 6,7-dimethoxyquinazoline-2,4(1H,3H)-dione.

[0026] (3) The method of the present invention can achieve dual upgrading and transformation of waste PC, and can simultaneously obtain the reaction products bisphenol A and quinazoline-2,4(1H,3H)-dione compounds, and bisphenol A and quinazoline-2,4(1H,3H)-dione compounds are easy to separate. These two reaction products, as high-value-added chemical monomers, can be further used for synthesizing functional chemical substances. Brief Description of the Drawings

[0027] Figure 1 It is the reaction route diagram of representative Example 1.

[0028] Figure 2 It is the 1H NMR spectrum of the reaction product bisphenol A.

[0029] Figure 3 It is the 13C NMR spectrum of the reaction product bisphenol A.

[0030] Figure 4 It is the 1H NMR spectrum of the reaction product quinazoline-2,4(1H,3H)-dione.

[0031] Figure 5 It is the 13C NMR spectrum of the reaction product quinazoline-2,4(1H,3H)-dione. Detailed implementation mode

[0032] The present invention will be further clarified below in conjunction with embodiments and the accompanying drawings. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. The operating methods without specific conditions noted in the following embodiments are usually carried out under conventional conditions or according to the conditions recommended by the manufacturer. The content not described in detail in this specification belongs to the prior art well-known to those skilled in the art. The experimental materials used in the following embodiments can be obtained from conventional biochemical reagent companies without special instructions.

[0033] The reaction processes of the following examples and comparative examples were all carried out under atmospheric pressure without applying additional pressure.

[0034] Comparative Example 1

[0035] 0.254 g of PC powder with CR purity (1 mmol), 0.236 g of 2-aminobenzonitrile (2 mmol), 0.02 g of water and N N-methylpyrrolidone (2 mL) were added into a pressure-resistant tube reactor equipped with an electromagnetic stirrer, a thermocouple, and a programmable temperature controller. After placing the pressure-resistant tube reactor, 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, it was cooled to room temperature, and the resulting mixed solution was the product. 60 μL of the resulting mixed solution was taken, and then 600 μL of deuterated DMSO was added, and the yield was measured by a nuclear magnetic resonance spectrometer. The results showed that no products quinazoline-2,4(1H,3H)-dione and bisphenol A were formed.

[0036] Comparative Example 2

[0037] 0.254 g of PC powder with CR purity (1 mmol), 0.236 g of 2-aminobenzonitrile (2 mmol), 0.0608 g of DBU (0.4 mmol) and N N-methylpyrrolidone (2 mL) were added into a pressure-resistant tube reactor equipped with an electromagnetic stirrer, a thermocouple, and a programmable temperature controller. After placing the pressure-resistant tube reactor, 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, it was cooled to room temperature, and the resulting mixed solution was the product. 60 μL of the resulting mixed solution was taken, and then 600 μL of deuterated DMSO was added, and the yield was measured by a nuclear magnetic resonance spectrometer. The results showed that the yield of the product quinazoline-2,4(1H,3H)-dione was 36%, and the yield of bisphenol A was 99%.

[0038] Example 1

[0039] In a pressure-resistant tube reactor equipped with an electromagnetic stirrer, a thermocouple, and a programmable temperature controller, 0.254 g of PC powder with CR purity (1 mmol), 0.236 g of 2-aminobenzonitrile (2 mmol), 0.0608 g of DBU (0.4 mmol), 0.02 g of water, and N N-methylpyrrolidone (2 mL) were added. After placing the pressure-resistant tube reactor, 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 lowered to room temperature, and the resulting mixture was the product. 60 μL of the resulting mixture was taken, and 600 μL of deuterated DMSO was added, and the yield was determined by a nuclear magnetic resonance spectrometer. The results showed that the yield of quinazoline-2,4(1H,3H)-dione was 95%, and the yield of bisphenol A was 99%.

[0040] The reaction route diagram of the present invention is as shown in Figure 1 Specifically, the method for separating bisphenol A and quinazoline-2,4(1H,3H)-dione is as follows: Ethyl acetate and water were added to the mixture obtained after the reaction was completed. Quinazoline-2,4(1H,3H)-dione is insoluble in water and ethyl acetate and thus precipitated directly, and bisphenol A was further separated by column chromatography.

[0041] The nuclear magnetic resonance hydrogen spectrum and nuclear magnetic resonance carbon spectrum of the product bisphenol A are respectively as shown in Figure 2 and Figure 3 shown, and the nuclear magnetic resonance hydrogen spectrum and nuclear magnetic resonance carbon spectrum of the product quinazoline-2,4(1H,3H)-dione are respectively as shown in Figure 4 and Figure 5 shown.

[0042] Example 2

[0043] In a pressure-resistant tube reactor equipped with an electromagnetic stirrer, a thermocouple, and a programmable temperature controller, 0.254 g of PC powder with CR purity (1 mmol), different molar amounts of 2-aminobenzonitrile (0.5, 1, 1.2, 1.4, 1.6, 1.8, 2, 2.5, 3 mmol), DBU (0.4 mmol), 0.02 g of water, and N N-methylpyrrolidone (2 mL) were added. After placing the pressure-resistant tube reactor, 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 lowered to room temperature, 60 μL of the resulting mixture was taken, and 600 μL of deuterated DMSO was added, and the yield was determined by a nuclear magnetic resonance spectrometer. The results showed that the yields of quinazoline-2,4(1H,3H)-dione in this example were 19%, 39%, 63%, 67%, 77%, 87%, 95%, 92%, 89% respectively, and the yields of bisphenol A were 92%, 92%, 94%, 94%, 95%, 95%, 99%, 99% and 99%.

[0044] Example 3

[0045] In a pressure-resistant tube reactor equipped with an electromagnetic stirrer, a thermocouple, and a programmable temperature controller, 0.254 g of PC powder with CR purity (1 mmol), 0.236 g of 2-aminobenzonitrile (2 mmol), different molar amounts of DBU (calculated based on the molar amount of 2-aminobenzonitrile being 100%, 3%, 5%, 7%, 10%, 15%, 20%, 25%, 30%, 40%, and 50% mol / mol), 0.02 g of water, and N N-methylpyrrolidone (2 mL) were added. After placing the pressure-resistant tube reactor, 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, it was cooled to room temperature, and the resulting mixed solution was the product. 60 μL of the resulting mixed solution was taken, and 600 μL of deuterated DMSO was added, and the yield was measured by a nuclear magnetic resonance spectrometer. The results showed that the yields of quinazoline-2,4(1H,3H)-dione in this example were 33%, 40%, 64%, 71%, 88%, 95%, 95%, 94%, 93%, and 93% respectively, and the yields of bisphenol A were 99%, 99%, 99%, 99%, 99%, 99%, 99%, 99%, 99%, and 99%.

[0046] Example 4

[0047] In a pressure-resistant tube reactor equipped with an electromagnetic stirrer, a thermocouple, and a programmable temperature controller, 0.254 g of PC powder with CR purity (1 mmol), 0.236 g of 2-aminobenzonitrile (2 mmol), different base catalysts (DBU, TBD, DBN, DMAP, MTBD, DABCO, TEDA, DIPEA, sodium hydroxide, potassium hydroxide, cesium hydroxide, sodium carbonate, potassium carbonate, and cesium carbonate) (0.4 mmol), 0.02 g of water, and N N-methylpyrrolidone (2 mL) were added. After placing the pressure-resistant tube reactor, 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, it was cooled to room temperature, and the resulting mixed solution was the product. 60 μL of the resulting mixed solution was taken, and 600 μL of deuterated DMSO was added, and the yield was measured by a nuclear magnetic resonance spectrometer. The results showed that the yields of quinazoline-2,4(1H,3H)-dione in this example were 95%, 83%, 61%, 76%, 73%, 77%, 65%, 73%, 66%, 69%, 95%, 20%, 60%, and 92% respectively, and the yields of bisphenol A were 99%, 96%, 95%, 96%, 94%, 96%, 96%, 97%, 96%, 97%, 99%, 94%, 94%, and 99%.

[0048] Example 5

[0049] In a pressure-resistant tube reactor equipped with an electromagnetic stirrer, a thermocouple, and a programmable temperature controller, 0.254 g of PC powder with a CR purity (1 mmol), 0.236 g of 2-aminobenzonitrile (2 mmol), DBU (0.4 mmol), 0.02 g of water, and N N-methylpyrrolidone (2 mL) were added respectively. After placing the pressure-resistant tube reactor, stirring and heating were started. The reaction system was heated to different temperatures (100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C, 160 °C) and reacted at the corresponding temperatures for 4 hours. After the reaction was completed, the temperature was lowered to room temperature, and the resulting mixed solution was the product. 60 μL of the resulting mixed solution was taken, and then 600 μL of deuterated DMSO was added. The yield was measured by a nuclear magnetic resonance spectrometer. The results showed that the yields of quinazoline-2,4(1H,3H)-dione in this example were 85%, 90%, 90%, 95%, 92%, 92%, and 88% respectively, and the yields of bisphenol A were 99%, 99%, 99%, 99%, 99%, 99%, and 99%.

[0050] Example 6

[0051] Waste PC plastics (water buckets, polycarbonate sheets, PC tubes, and transparent plates) were pre-crushed to centimeter size, and then 0.254 g of the centimeter-sized crushed material of the above-mentioned PC plastics (about 1 mmol), 0.236 g of 2-aminobenzonitrile (2 mmol), DBU (0.4 mmol), 0.02 g of water, and N N-methylpyrrolidone (2 mL) were added respectively. After placing the pressure-resistant tube reactor, 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 lowered to room temperature, and the resulting mixed solution was the product. 60 μL of the resulting mixed solution was taken, and then 600 μL of deuterated DMSO was added. The yield was measured by a nuclear magnetic resonance spectrometer. The results showed that the yields of quinazoline-2,4(1H,3H)-dione in this example were 88%, 94%, 94%, and 93% respectively, and the yields of bisphenol A were 96%, 99%, 99%, and 99%.

[0052] Example 7

[0053] In a pressure-resistant tube reactor equipped with an electromagnetic stirrer, a thermocouple, and a programmable temperature controller, 0.254 g of PC powder with a CR purity (1 mmol), 0.236 g of 2-aminobenzonitrile (2 mmol), DBU (0.4 mmol), different masses of water (0.25 g, 0.20 g, 0.15 g, 0.1 g, 0.06 g, 0.04 g, 0.02 g, 0.008 g, 0.004 g, 0.002 g) and N -methylpyrrolidone (2 mL) were added. After placing the pressure-resistant tube reactor, 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 lowered to room temperature, and the resulting mixed solution was the product. 60 μL of the resulting mixed solution was taken, and 600 μL of deuterated DMSO was added, and the yield was measured by a nuclear magnetic resonance spectrometer. The results showed that the yields of quinazoline-2,4(1H,3H)-dione in this example were 69%, 71%, 77%, 84%, 85%, 86%, 95%, 87%, 84%, and 78% respectively, and the yields of bisphenol A were 99%, 99%, 99%, 99%, 99%, 99%, 99%, 99%, 99%, and 99%.

[0054] Example 8

[0055] In a pressure-resistant tube reactor equipped with an electromagnetic stirrer, a thermocouple, and a programmable temperature controller, 0.254 g of PC (1 mmol), different 2-aminobenzonitrile derivatives (2-amino-5-fluorobenzonitrile, 2-amino-4-chlorobenzonitrile, 2-amino-5-chlorobenzonitrile, 2-amino-5-bromobenzonitrile, 2-amino-4-methylbenzonitrile, 2-amino-5-methylbenzonitrile, 2-amino-4,5-dimethoxybenzonitrile) (2 mmol), 0.0608 g of DBU (0.4 mmol), 0.02 g of water and N-Methylpyrrolidone (2 mL). After placing the pressure-resistant 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, cool down to room temperature, and the resulting mixed solution is the product. Take 60 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 yields of quinazoline-2,4(1H,3H)-dione compounds in this example (6-fluoroquinazoline-2,4(1H,3H)-dione, 7-chloroquinazoline-2,4(1H,3H)-dione, 6-chloroquinazoline-2,4(1H,3H)-dione, 6-bromoquinazoline-2,4(1H,3H)-dione, 6-methylquinazoline-2,4(1H,3H)-dione, 7-methylquinazoline-2,4(1H,3H)-dione, and 6,7-dimethoxyquinazoline-2,4(1H,3H)-dione) are 90%, 85%, 88%, 93%, 81%, 90%, and 87% respectively, and the yields of bisphenol A are 94%, 97%, 96%, 99%, 96%, 97%, and 98%.

[0056] Example 9

[0057] Add 0.254 g of PC (1 mmol), 0.236 g of 2-aminobenzonitrile (2 mmol), 0.0608 g of DBU (0.4 mmol), 0.02 g of water and N -Methylpyrrolidone (2 mL) into a pressure-resistant tube reactor equipped with an electromagnetic stirrer, a thermocouple, and a programmable temperature controller. After placing the pressure-resistant tube reactor, start stirring and heating. The reaction system is heated to 130 °C and reacted at this temperature for 1, 2, 3, 4, 5, and 6 hours respectively. After the reaction is completed, cool down to room temperature, and the resulting mixed solution is the product. Take 60 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 yields of quinazoline-2,4(1H,3H)-dione in this example are 72%, 77%, 87%, 95%, 94%, 95% respectively, and the yields of bisphenol A are 99%, 99%, 99%, 99%, 99%, and 99%.

[0058] Example 10

[0059] Add 0.254 g of PC powder with CR purity (1 mmol), 0.236 g of 2-aminobenzonitrile (2 mmol), DBU (0.4 mmol), 0.02 g of water and different solvents ( N -Methylpyrrolidone, N,N -Dimethylformamide, N,N-Dimethylacetamide, 1,4-dioxane, acetonitrile, dimethyltetrahydrofuran) (2 mL). After placing the pressure-resistant 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 mixture is the product. Take 60 µL of the resulting mixture, add 600 µL of deuterated DMSO, and determine the yield by nuclear magnetic resonance spectrometer. The results show that the yields of quinazoline-2,4(1H,3H)-dione in this example are 95%, 93%, 90%, 11%, 3% and 6% respectively, and the yields of bisphenol A are 99%, 99%, 99%, 87%, 80% and 93%.

[0060] The above embodiments have described the technical solutions of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, supplements or substitutions in a similar manner within the principle scope of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing bisphenol A and heterocyclic compounds using waste PC, characterized in that: The following steps are involved: A reaction system is constructed by using crushed waste polycarbonate PC plastic, aminobenzonitrile compounds, a base catalyst and a solvent, and the reaction system is placed at a temperature of 100 to 160° C. in an air atmosphere for a reaction of ≥30 min to obtain bisphenol A and a heterocyclic compound, wherein the heterocyclic compound is quinazoline-2,4(1H,3H)-dione or a derivative thereof; The aminobenzonitrile compound is selected from 2-aminobenzonitrile, 2-amino-5-fluorobenzonitrile, 2-amino-4-chlorobenzonitrile, 2-amino-5-chlorobenzonitrile, 2-amino-5-bromobenzonitrile, 2-amino-4-methylbenzonitrile, 2-amino-5-methylbenzonitrile or 2-amino-4,5-dimethoxybenzonitrile; The base catalyst is 1,8-diazabicyclo[5.4.0]undec-7-ene; The solvent includes water and an organic solvent; the organic solvent is N -Methylpyrrolidone, N,N -dimethylformamide or N, N - one of dimethylacetamide, in which the mass ratio of water to organic solvent is 0.0005-0.15:1; The molar ratio of the aminobenzonitrile compound to the waste PC is 1.2 to 3:1, and the molar amount of the base catalyst added is 7% to 50% based on the molar number of the aminobenzonitrile compound as 100%. The product heterocyclic compound is selected from quinazoline-2,4(1H,3H)-dione, 6-fluoroquinazoline-2,4(1H,3H)-dione, 7-chloroquinazoline-2,4(1H,3H)-dione, 6-chloroquinazoline-2,4(1H,3H)-dione, 6-bromoquinazoline-2,4(1H,3H)-dione, 6-methylquinazoline-2,4(1H,3H)-dione, 7-methylquinazoline-2,4(1H,3H)-dione or 6,7-dimethoxyquinazoline-2,4(1H,3H)-dione.

2. The method for preparing bisphenol A and heterocyclic compounds using waste PC according to claim 1, characterized in that: The ratio of solvent to waste PC is 1-5 mL:1 mmol.

3. The method for preparing bisphenol A and heterocyclic compounds using waste PC according to claim 1, characterized in that: The ratio of solvent to waste PC is 2-2.5 mL:1 mmol.

4. The method for preparing bisphenol A and heterocyclic compounds using waste PC according to claim 1, characterized in that: The reaction time is 30 min to 12 h.

5. The method for preparing bisphenol A and heterocyclic compounds using waste PC according to claim 1, characterized in that: Waste PC includes waste PC bottles, waste PC plates, waste PC sheets, waste PC lamps or waste PC films.

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