A method for upgrading polycarbonate to phenol

Abstract

The application discloses a method for upgrading polycarbonate to phenol, and belongs to the field of phenol production. The method comprises the following steps: (1) crushing polycarbonate waste; (2) mixing the crushed polycarbonate waste with water, methanol and a catalyst, and reacting in a closed pressure container with a non-active atmosphere; the catalyst is a potassium-loaded catalyst. The phenol yield can reach 92%, and the selectivity can reach 95%. The application provides a method for producing phenol from polycarbonate waste such as optical discs and automobile lampshades, and the method is environmentally friendly, simple in process, easy to operate, high in processing efficiency, and can obtain a widely-applied platform chemical, i.e. phenol.

Description

TECHNICAL FIELD

[0001] The application relates to a method for upgrading polycarbonate to phenol, and belongs to the field of phenol production. BACKGROUND

[0002] Polycarbonate is an excellent engineering plastic due to its high impact resistance, ductility and excellent optical clarity, but the service life of polycarbonate products is generally short, and the natural degradation rate is extremely slow. Traditional methods such as landfill, incineration and mechanical recycling will cause the main monomer bisphenol A to enter the ecological system, causing serious pollution problems. In recent years, chemical recycling of polymer waste has been paid great attention. The amount of polycarbonate waste from compact discs and plastic articles is increasing, so it is necessary to develop an appropriate process to recycle these materials.

[0003] Phenol is an important organic synthesis raw material, which is widely used in medicine, plastic and resin synthesis, pesticide production, and is an important platform molecule for the production of value-added chemical intermediates and products. Phenol was first obtained by refining from coal tar. At present, the production methods in China include cumene method and sulfonation method. However, the product separation process of the above methods is relatively complex, and there is an environmental safety problem of using highly toxic solvents.

[0004] At present, the research reports on the upgrading and conversion of polycarbonate, due to the high bond energy of carbon-carbon bond, the main product is mostly its structural monomer bisphenol A. Mainly include alcoholysis method, ammonolysis method, hydrogenation method, pyrolysis method, etc., but due to the high molecular structure of polycarbonate, the bond energy of carbon-carbon bond is high, and the bond breaking is difficult, which requires harsh reaction conditions and high energy consumption.

[0005] Therefore, in view of the problems such as high reaction temperature and use of highly toxic solvents in the upgrading and conversion process of polycarbonate, it is urgent to develop an efficient reaction system to reduce the reaction temperature of polycarbonate upgrading and conversion to reduce the energy consumption required by the reaction, and further convert the product into phenol which has a broader application space, so that it can not only solve the environmental problems caused by waste polycarbonate, but also produce more valuable platform molecule chemicals, which has important significance for sustainable development and protection of ecological environment. SUMMARY

[0006] The application develops a method for producing phenol, which realizes a revolutionary technology for preparing phenol from polycarbonate waste under mild conditions, and provides important energy security for the sustainable development of China's economy.

[0007] A method for upgrading polycarbonate to phenol, the method at least comprises the following steps:

[0008] (1) crushing the polycarbonate waste;

[0009] (2) mixing the crushed polycarbonate waste with water, methanol and a catalyst, and reacting in a closed pressure vessel with a non-reactive atmosphere;

[0010] The catalyst is a potassium-loaded catalyst.

[0011] Optionally, the potassium-loaded catalyst is at least one of K-TiO2, K-CeO2, K-CNT, K-CTF, K-Al2O3 or K-ZrO2.

[0012] Optionally, the mass content of K element in the potassium-loaded catalyst is 5-40%.

[0013] Preferably, the mass content of K element is 5-30%.

[0014] Further preferably, the mass content of K element is 5-20%.

[0015] Optionally, in step (1), the crushing is to process the polycarbonate waste into particles with a particle size less than 1 cm.

[0016] Preferably, the size of the particles is 4-200 mesh.

[0017] Optionally, in step (1), the polycarbonate waste is selected from at least one of compact discs, automobile lampshades, optical lenses, medical safety masks, high-pressure syringe housings, and polycarbonate rain shelters.

[0018] Optionally, in step (2), the volume of water and methanol is 10-65% of the total volume of the pressure vessel.

[0019] Preferably, the volume of water and methanol is 20-50% of the total volume of the pressure vessel.

[0020] Further preferably, the volume of water and methanol is 30-45% of the total volume of the pressure vessel.

[0021] Optionally, the volume ratio of water to methanol is 20-0:1.

[0022] Further preferably, the volume ratio of water to methanol is 10-0:1.

[0023] Optionally, in step (2), the amount of the crushed polycarbonate waste added is 1-25% of the mass of the water and methanol.

[0024] Preferably, the amount of the crushed polycarbonate waste added is 1-15% of the mass of the water and methanol.

[0025] Further preferably, the amount of the crushed polycarbonate waste added is 2-10% of the mass of the water and methanol.

[0026] Optionally, in step (2), the catalyst is added in an amount of 5-60% of the mass of the crushed polycarbonate waste.

[0027] Preferably, the catalyst is added in an amount of 5-30% of the mass of the crushed polycarbonate waste.

[0028] Optionally, in step (2), the reaction temperature is 150-350℃.

[0029] Preferably, the reaction temperature is 200-330℃.

[0030] Further preferably, the reaction temperature is 220-300℃.

[0031] Optionally, in step (2), the reaction time is 1-12h.

[0032] Preferably, the reaction time is 2-10h.

[0033] Further preferably, the reaction time is 2-6h.

[0034] Optionally, the non-reactive atmosphere is a nitrogen atmosphere.

[0035] Optionally, the method further comprises a step of separating and reusing the catalyst.

[0036] In particular, the catalyst is separated and reused by centrifugal filtration.

[0037] The polycarbonate waste such as compact discs and automobile lampshades is directly catalytically converted into phenol under mild conditions by the above method, wherein the phenol yield can be as high as 92%, and the selectivity is as high as 95%, which reduces the complex operation of the separation process, and the prepared phenol is an important platform chemical, which has a wide application prospect in chemical production.

[0038] The present application provides a method for producing phenol from polycarbonate waste such as compact discs and automobile lampshades, which is environmentally friendly, simple in process, easy to operate, and high in processing efficiency, and obtains the important platform chemical phenol. The present application designs and develops a high-efficiency catalytic reaction system, which can break the carbon-carbon bond of polycarbonate at a lower temperature, and catalytically converts polycarbonate to directly prepare phenol. The present application realizes a revolutionary technology for preparing phenol from waste plastics under mild conditions, and the product phenol is an important organic synthesis raw material, which is widely used in medicine, plastic and resin synthesis, pesticide production, and is an important platform molecule for synthesizing value-added chemical intermediates and products.

[0039] The beneficial effects that can be produced by the present application include:

[0040] 1) The present application realizes the direct conversion of polycarbonate waste such as catalytic light discs and automobile lampshades to phenol under low reaction temperature and pressure conditions, and the reaction conditions are mild, thus the requirements for the reaction equipment are low, and the present application has great industrialization potential.

[0041] 2) The catalyst used in the present application can be directly separated and further recycled, thus reducing the cost of the process.

[0042] 3) The operation steps of the method of the present application are simple, easy to operate, low in energy consumption, and the process is green, and it is an environmentally friendly process. DETAILED DESCRIPTION

[0043] The present application will be described in detail below in combination with examples, but the present application is not limited to these examples.

[0044] Unless otherwise specified, the raw materials and catalysts in the examples of the present application are purchased through commercial channels.

[0045] Unless otherwise specified, the test methods all use conventional methods, and the instrument settings all use the recommended settings of the manufacturers.

[0046] The supported potassium type catalyst in the examples of the present application: the supported potassium type catalyst is obtained by adding a 5%-20% mass fraction of KNO3 solution to different supports, stirring and drying, and then calcining in a nitrogen tube furnace. Among them, TiO2, CeO2, CNT, Al2O3 and ZrO2 are purchased from Aldrich Company. In addition, CTF is obtained by mixing and calcining zinc chloride and terephthalic dinitrile.

[0047] In the examples, the first number of the catalyst refers to the mass content of KNO3. For example, 20K-TiO2 refers to the mass content of KNO3 being 20%.

[0048] The phenol yield in the examples of the present application is calculated as follows:

[0049]

[0050] Example 1

[0051] The compact discs were crushed, and then 0.2 g of the crushed compact disc particles having a particle size of 4-200 mesh were added to a 50 mL reaction kettle, 10 mL of water and 10 mL of methanol were sequentially added as a reaction solvent, and 0.02 g of 20K-TiO2 was added as a catalyst, and the mixture was stirred by magnetic force. The reaction kettle was sealed, the gas in the reaction kettle was replaced with nitrogen 5 times, and the inlet and outlet were closed. The temperature was raised to 300°C by electric heating under magnetic stirring at 400 rpm, and the temperature was maintained for 600 min. After the reaction was completed, the stirring was stopped, the reaction kettle was cooled to room temperature with ice water, 10 mL of the reaction solution was taken, 60 mg of n-dodecane was added as an internal standard, and 10 mL of ethyl acetate was added. The catalyst after the reaction was separated by centrifugation, and was further recycled.

[0052] Through qualitative and quantitative analysis of the liquid product, it was found that the catalytic compact disc particles could be directly converted to prepare phenol, and the yield of phenol was 92%.

[0053] Example 2

[0054] The compact discs were crushed, and then 0.5 g of the crushed compact disc particles having a particle size of 4-200 mesh were added to a 50 mL reaction kettle, 5 mL of water and 15 mL of methanol were sequentially added as a reaction solvent, and 0.02 g of 20K-ZrO2 was added as a catalyst, and the mixture was stirred by magnetic force. The reaction kettle was sealed, the gas in the reaction kettle was replaced with nitrogen 5 times, and the inlet and outlet were closed. The temperature was raised to 300°C by electric heating under magnetic stirring at 400 rpm, and the temperature was maintained for 300 min. After the reaction was completed, the stirring was stopped, the reaction kettle was cooled to room temperature with ice water, 10 mL of the reaction solution was taken, 60 mg of n-dodecane was added as an internal standard, and 10 mL of ethyl acetate was added. The catalyst after the reaction was separated by centrifugation, and was further recycled.

[0055] Through qualitative and quantitative analysis of the liquid product, it was found that the catalytic compact disc particles could be directly converted to prepare phenol, and the yield of phenol was 55%.

[0056] Example 3

[0057] The compact disc was crushed, and then 1.0 g of the crushed compact disc particles having a particle size of 4-200 mesh was added to a 50 mL reaction kettle, 10 mL of water and 10 mL of methanol were sequentially added as a reaction solvent, and 0.02 g of 20K-CeO2 was added as a catalyst, and the mixture was stirred by magnetic force. The reaction kettle was sealed, the gas in the reaction kettle was replaced with nitrogen 5 times, and then the inlet and outlet were closed. The temperature was increased to 310°C by electric heating under magnetic stirring at 1000 rpm, and the temperature was maintained for 400 min. After the reaction was completed, the stirring was stopped, the reaction kettle was cooled to room temperature with ice water, 10 mL of the reaction solution was taken, 60 mg of n-dodecane was added as an internal standard, and 10 mL of ethyl acetate was added. The catalyst after the reaction was separated by centrifugation, and was further recycled.

[0058] Through qualitative and quantitative analysis of the liquid product, it was found that the direct conversion of the catalytic compact disc particles could prepare phenol, and the yield of phenol was 85%.

[0059] Example 4

[0060] The compact disc was crushed, and then 0.6 g of the crushed compact disc particles having a particle size of 4-200 mesh was added to a 50 mL reaction kettle, 10 mL of water and 10 mL of methanol were sequentially added as a reaction solvent, and 0.02 g of 20K-CNT was added as a catalyst, and the mixture was stirred by magnetic force. The reaction kettle was sealed, the gas in the reaction kettle was replaced with nitrogen 5 times, and then the reaction kettle was filled with hydrogen gas to 4.0 MPa, and the inlet and outlet were closed. The temperature was increased to 330°C by electric heating under magnetic stirring at 1000 rpm, and the temperature was maintained for 420 min. After the reaction was completed, the stirring was stopped, the reaction kettle was cooled to room temperature with ice water, 10 mL of the reaction solution was taken, 60 mg of n-dodecane was added as an internal standard, and 10 mL of ethyl acetate was added. The catalyst after the reaction was separated by centrifugation, and was further recycled.

[0061] Through qualitative and quantitative analysis of the liquid product, it was found that the direct conversion of the catalytic compact disc particles could prepare phenol, and the yield of phenol was 87%.

[0062] Example 5

[0063] The compact disc was crushed, and then 0.6 g of the crushed compact disc particles with a particle size of 4-200 mesh were added into a 50 mL reactor, 5 mL of water and 15 mL of methanol were added as reaction solvents, and 0.02 g of 20K-CTF was added as a catalyst, and the mixture was stirred by magnetic force. The reactor was sealed, and the gas in the reactor was replaced with nitrogen for 5 times, and then the inlet and outlet were closed. The temperature was raised to 240°C by electric heating under magnetic stirring at 1000 rpm, and the temperature was maintained for 500 min. After the reaction was completed, the stirring was stopped, the reactor was cooled to room temperature by ice water, 10 mL of the reaction solution was taken, 60 mg of n-dodecane was added as an internal standard, and 10 mL of ethyl acetate was added. The catalyst after the reaction was separated by centrifugation, and was further recycled.

[0064] Through qualitative and quantitative analysis of the liquid product, it was found that the direct conversion of the catalytic compact disc particles could prepare phenol, and the yield of phenol was 88%.

[0065] Example 6

[0066] The compact disc was crushed, and then 0.2 g of the crushed compact disc particles with a particle size of 4-200 mesh were added into a 50 mL reactor, 10 mL of water and 10 mL of methanol were added as reaction solvents, and 0.02 g of 20K-Al2O3 was added as a catalyst, and the mixture was stirred by magnetic force. The reactor was sealed, and the gas in the reactor was replaced with hydrogen for 5 times, and then the reactor was filled with hydrogen to 5.0 MPa, and the inlet and outlet were closed. The temperature was raised to 320°C by electric heating under magnetic stirring at 1000 rpm, and the temperature was maintained for 600 min. After the reaction was completed, the stirring was stopped, the reactor was cooled to room temperature by ice water, 10 mL of the reaction solution was taken, 60 mg of n-dodecane was added as an internal standard, and 10 mL of ethyl acetate was added. The catalyst after the reaction was separated by centrifugation, and was further recycled.

[0067] Through qualitative and quantitative analysis of the liquid product, it was found that the direct conversion of the catalytic compact disc particles could prepare phenol, and the yield of phenol was 71%.

[0068] Example 7

[0069] The preparation process described in Example 1 was repeated, except that the compact disc was replaced by a car lamp shade, and the main product obtained was phenol, and the yield of phenol was 85%.

[0070] Example 8

[0071] The preparation process described in Example 2 was repeated, except that the compact disc was replaced by a car lamp shade, and the main product obtained was phenol, and the yield of phenol was 51%.

[0072] Example 9

[0073] The preparation procedure described in Example 3 was repeated, except that the compact disc was replaced with a car headlight lens, and the main product obtained was phenol, with a yield of 82% phenol.

[0074] Example 10

[0075] The preparation procedure described in Example 4 was repeated, except that the compact disc was replaced with a car headlight lens, and the main product obtained was phenol, with a yield of 75% phenol.

[0076] Example 11

[0077] The preparation procedure described in Example 5 was repeated, except that the compact disc was replaced with a car headlight lens, and the main product obtained was phenol, with a yield of 84% phenol.

[0078] Example 12

[0079] The preparation procedure described in Example 6 was repeated, except that the compact disc was replaced with a car headlight lens, and the main product obtained was phenol, with a yield of 75% phenol.

[0080] Example 13

[0081] The preparation procedure described in Example 1 was repeated, except that the compact disc was replaced with a polycarbonate plastic cup, and the main product obtained was phenol, with a yield of 88% phenol.

[0082] Example 14

[0083] The preparation procedure described in Example 2 was repeated, except that the compact disc was replaced with a polycarbonate plastic cup, and the main product obtained was phenol, with a yield of 58% phenol.

[0084] Example 15

[0085] The preparation procedure described in Example 3 was repeated, except that the compact disc was replaced with a polycarbonate plastic cup, and the main product obtained was phenol, with a yield of 79% phenol.

[0086] Example 16

[0087] The preparation procedure described in Example 4 was repeated, except that the compact disc was replaced with a polycarbonate plastic cup, and the main product obtained was phenol, with a yield of 74% phenol.

[0088] Example 17

[0089] The preparation procedure described in Example 5 was repeated, except that the compact disc was replaced with a polycarbonate plastic cup, and the main product obtained was phenol, with a yield of 83% phenol.

[0090] Example 18

[0091] The procedure described in Example 6 was repeated except that the compact disc was replaced with a polycarbonate plastic cup and the main product obtained was phenol with a yield of 77%.

[0092] Example 19

[0093] The procedure described in Example 1 was repeated except that the compact disc was replaced with a medical safety mask and the main product obtained was phenol with a yield of 78%.

[0094] Example 20

[0095] The procedure described in Example 2 was repeated except that the compact disc was replaced with a medical safety mask and the main product obtained was phenol with a yield of 57%.

[0096] Example 21

[0097] The procedure described in Example 3 was repeated except that the compact disc was replaced with a medical safety mask and the main product obtained was phenol with a yield of 86%.

[0098] Example 22

[0099] The procedure described in Example 4 was repeated except that the compact disc was replaced with a medical safety mask and the main product obtained was phenol with a yield of 77%.

[0100] Example 23

[0101] The procedure described in Example 5 was repeated except that the compact disc was replaced with a medical safety mask and the main product obtained was phenol with a yield of 87%.

[0102] Example 24

[0103] The procedure described in Example 6 was repeated except that the compact disc was replaced with a medical safety mask and the main product obtained was phenol with a yield of 73%.

[0104] Example 25

[0105] The procedure described in Example 1 was repeated except that the compact disc was replaced with an optical lens and the main product obtained was phenol with a yield of 83%.

[0106] Example 26

[0107] The procedure described in Example 2 was repeated except that the compact disc was replaced with an optical lens and the main product obtained was phenol with a yield of 53%.

[0108] Example 27

[0109] The preparation procedure described in Example 3 was repeated except that the optical disc was replaced with an optical lens to obtain the main product phenol with a yield of 83% of phenol.

[0110] Example 28

[0111] The preparation procedure described in Example 4 was repeated except that the optical disc was replaced with an optical lens to obtain the main product phenol with a yield of 76% of phenol.

[0112] Example 29

[0113] The preparation procedure described in Example 5 was repeated except that the optical disc was replaced with an optical lens to obtain the main product phenol with a yield of 80% of phenol.

[0114] Example 30

[0115] The preparation procedure described in Example 6 was repeated except that the optical disc was replaced with an optical lens to obtain the main product phenol with a yield of 78% of phenol.

[0116] Example 31

[0117] The preparation procedure described in Example 1 was repeated except that the optical disc was replaced with a high pressure syringe housing to obtain the main product phenol with a yield of 83% of phenol.

[0118] Example 32

[0119] The preparation procedure described in Example 2 was repeated except that the optical disc was replaced with a high pressure syringe housing to obtain the main product phenol with a yield of 49% of phenol.

[0120] Example 33

[0121] The preparation procedure described in Example 3 was repeated except that the optical disc was replaced with a high pressure syringe housing to obtain the main product phenol with a yield of 78% of phenol.

[0122] Example 34

[0123] The preparation procedure described in Example 4 was repeated except that the optical disc was replaced with a high pressure syringe housing to obtain the main product phenol with a yield of 75% of phenol.

[0124] Example 35

[0125] The procedure described in Example 5 was repeated except that the compact disc was replaced with a high pressure syringe housing and the major product obtained was phenol in 83% yield.

[0126] Example 36

[0127] The procedure described in Example 6 was repeated except that the compact disc was replaced with a high pressure syringe housing and the major product obtained was phenol in 73% yield.

[0128] Example 37

[0129] The procedure described in Example 1 was repeated except that the compact disc was replaced with a polycarbonate rain shelter and the major product obtained was phenol in 81% yield.

[0130] Example 38

[0131] The procedure described in Example 2 was repeated except that the compact disc was replaced with a polycarbonate rain shelter and the major product obtained was phenol in 48% yield.

[0132] Example 39

[0133] The procedure described in Example 3 was repeated except that the compact disc was replaced with a polycarbonate rain shelter and the major product obtained was phenol in 77% yield.

[0134] Example 40

[0135] The procedure described in Example 4 was repeated except that the compact disc was replaced with a polycarbonate rain shelter and the major product obtained was phenol in 65% yield.

[0136] Example 41

[0137] The procedure described in Example 5 was repeated except that the compact disc was replaced with a polycarbonate rain shelter and the major product obtained was phenol in 79% yield.

[0138] Example 42

[0139] The procedure described in Example 6 was repeated except that the compact disc was replaced with a polycarbonate rain shelter and the major product obtained was phenol in 70% yield.

[0140] The above merely describes several embodiments of the present application, and does not limit the present application in any form. Although the present application is disclosed with the preferred embodiments, it is not intended to limit the present application. Any skilled person in the art can make some changes or modifications to the disclosed technical contents without departing from the scope of the technical solutions of the present application, and the equivalent embodiments are equivalent to the equivalent embodiments, which are within the scope of the technical solutions.

Claims

1. A method for converting polycarbonate into phenol, characterized in that, The method includes at least the following steps: (1) The polycarbonate waste is crushed; (2) The crushed polycarbonate waste is mixed with water, methanol and catalyst and reacted in a closed pressure vessel with an inactive atmosphere; The catalyst is a supported potassium catalyst; The supported potassium catalyst is at least one of K-TiO2, K-CeO2, K-CNT, K-CTF, K-Al2O3, or K-ZrO2; CTF is obtained by calcining anhydrous zinc chloride and terephthalonitrile.

2. The method according to claim 1, characterized in that, In the supported potassium catalyst, the mass content of potassium is 5-40%.

3. The method according to claim 2, characterized in that, The mass content of potassium (K) is 5-30%.

4. The method according to claim 3, characterized in that, The mass content of potassium (K) is 5-20%.

5. The method according to claim 1, characterized in that, In step (1), the crushing process involves processing the polycarbonate waste into particles with a diameter of less than 1 cm.

6. The method according to claim 5, characterized in that, The particle size is between 4 and 200 mesh.

7. The method according to claim 1, characterized in that, In step (1), the polycarbonate waste is selected from at least one of optical discs, automotive lamp covers, optical lenses, medical safety masks, high-pressure injector shells, and polycarbonate canopies.

8. The method according to claim 1, characterized in that, In step (2), the volume of water and methanol is 10-65% of the total volume of the pressure vessel.

9. The method according to claim 8, characterized in that, The volume of water and methanol is 20-50% of the total volume of the pressure vessel.

10. The method according to claim 9, characterized in that, The volume of water and methanol is 30-45% of the total volume of the pressure vessel.

11. The method according to claim 1, characterized in that, The volume ratio of water to methanol is 20 to 0:

1.

12. The method according to claim 11, characterized in that, The volume ratio of water to methanol is 10 to 0:

1.

13. The method according to claim 1, characterized in that, In step (2), the amount of the crushed polycarbonate waste added is 1 to 25% of the mass of the water and methanol.

14. The method according to claim 13, characterized in that, The amount of the pulverized polycarbonate waste added is 1 to 15% of the mass of the water and methanol.

15. The method according to claim 14, characterized in that, The amount of the pulverized polycarbonate waste added is 2-10% of the mass of the water and methanol.

16. The method according to claim 1, characterized in that, In step (2), the amount of catalyst added is 5 to 60% of the mass of the crushed polycarbonate waste.

17. The method according to claim 16, characterized in that, The amount of catalyst added is 5-30% of the mass of the pulverized polycarbonate waste.

18. The method according to claim 1, characterized in that, In step (2), the reaction temperature is 150~350℃. o C.

19. The method according to claim 18, characterized in that, The reaction temperature is 200~330℃. o C.

20. The method according to claim 19, characterized in that, The reaction temperature is 220~290℃. o C.

21. The method according to claim 1, characterized in that, In step (2), the reaction time is 1 to 12 hours.

22. The method according to claim 21, characterized in that, The reaction time is 2 to 10 hours.

23. The method according to claim 22, characterized in that, The reaction time is 2-6 hours.

24. The method according to claim 1, characterized in that, The method also includes steps for separating and reusing the catalyst.

Images