Method for appreciation conversion of polycarbonate into phenol

Abstract

The invention discloses a method for appreciation conversion of polycarbonate into phenol, and belongs to the field of phenol production. The method at least comprises the following steps: (1) crushing the polycarbonate waste; (2) mixing the crushed polycarbonate waste with water, methanol and a catalyst, and reacting in a closed pressure container with an inactive atmosphere; the catalyst is a supported potassium catalyst. Wherein the phenol yield can reach 92%, and the selectivity can reach 95%. The invention provides a method for producing phenol by using polycarbonate wastes such as optical disks and automobile lampshades, the process is environment-friendly, the process is simple and convenient, the operation is easy, the treatment efficiency is high, and the widely applied platform chemical phenol is obtained.

Description

Technical Field

[0001] The present application relates to a method for converting polycarbonate into phenol by value-added conversion, belonging to the field of phenol production. Background Art

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

[0003] Phenol is an important raw material for organic synthesis, 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 extracted from coal tar. Currently, there are two production methods in my country: the cumene method and the sulfonation method. However, the product separation process of the above methods is relatively complicated, and there are also environmental safety issues with the use of highly toxic solvents.

[0004] At present, the research reports on the value-added conversion of polycarbonate show that due to the high carbon-carbon bond energy, the main product is mostly its structural monomer bisphenol A. The main methods include alcoholysis, aminolysis, hydrogenation, thermal decomposition, etc. However, due to the polymer structure of polycarbonate, the carbon-carbon bond energy is high, the bond breaking is difficult, and more stringent reaction conditions and higher energy consumption are required.

[0005] Therefore, in response to the current problems of high reaction temperature or use of highly toxic solvents in the process of polycarbonate appreciation conversion, it is urgent to develop an efficient reaction system to reduce the reaction temperature of polycarbonate appreciation conversion to reduce the energy consumption required for the reaction, and further convert the product into phenol with a broader application space, so that it can meet the environmental problems caused by waste polycarbonate while also producing more valuable platform molecular chemicals, which is of great significance to sustainable development and protection of the ecological environment. Summary of the invention

[0006] The present invention develops a method for producing phenol, realizes a revolutionary technology for preparing phenol from polycarbonate waste under mild conditions, and provides important energy guarantee for the sustainable development of my country's economy.

[0007] A method for converting polycarbonate into phenol by value-added conversion, the method comprising at least the following steps:

[0008] (1) crushing polycarbonate waste;

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

[0010] The catalyst is a supported potassium catalyst.

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

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

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

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

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

[0016] Preferably, the size of the particles is between 4 and 200 meshes.

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

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

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

[0020] More 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 to 0:1.

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

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

[0024] Preferably, the amount of the crushed polycarbonate waste added is 1 to 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 amount of the catalyst added is 5 to 60% of the mass of the crushed polycarbonate waste.

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

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

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

[0030] More preferably, the reaction temperature is 220-300°C.

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

[0032] Preferably, the reaction time is 2 to 10 hours.

[0033] More preferably, the reaction time is 2 to 6 hours.

[0034] Optionally, the inert atmosphere is a nitrogen atmosphere.

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

[0036] Specifically, the separation and reuse of the catalyst is to centrifuge the catalyst and further recycle it for use.

[0037] The above steps and methods are used to directly catalytically convert polycarbonate waste materials such as optical disks and automobile lampshades into phenol under mild conditions, wherein the phenol yield can be as high as 92% and the selectivity can reach 95%, thereby reducing the complex operation of the separation process. The prepared phenol is an important platform chemical and has broad application prospects in chemical production.

[0038] The present invention provides a method for producing phenol from polycarbonate waste such as optical discs and automobile lampshades. The process is environmentally friendly, simple in process, easy to operate, and has high processing efficiency, and an important platform chemical phenol is obtained. The present invention designs and develops an efficient catalytic reaction system that can destroy the carbon-carbon bonds of polycarbonate at a relatively low temperature, catalyze the conversion of polycarbonate to directly prepare phenol. This is 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, and pesticide production, and is an important platform molecule for synthesizing value-added chemical intermediates and products.

[0039] The beneficial effects of this application include:

[0040] 1) The present invention realizes the direct conversion of polycarbonate waste such as optical discs and automobile lampshades into phenol under relatively low reaction temperature and pressure conditions. The reaction conditions are mild, so the requirements for reaction equipment are relatively low, and the invention has great industrialization potential.

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

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

[0043] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

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

[0045] Unless otherwise specified, conventional methods were used for testing and instrument settings were those recommended by the manufacturer.

[0046] The loaded potassium catalyst in the embodiment of the present application is: the loaded potassium catalyst is obtained by adding 5%-20% mass fraction of KNO3 solution to different carriers, stirring and drying, and then calcining in a nitrogen tube furnace to obtain the corresponding loaded potassium catalyst for catalytic reaction. Among them, TiO2, CeO2, CNT, Al2O3, and ZrO2 are purchased from Aladdin Company. In addition, CTF is obtained by calcining a mixture of aqueous zinc chloride and terephthalonitrile.

[0047] In the examples, the number before the catalyst refers to the mass content of KNO3, such as 20K-TiO2, which means the mass content of KNO3 is 20%.

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

[0049]

[0050] Example 1

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

[0052] Through qualitative and quantitative analysis of the liquid product, it was concluded that phenol can be prepared by direct conversion of the catalytic optical disc particles, wherein the yield of phenol is 92%.

[0053] Example 2

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

[0055] Through qualitative and quantitative analysis of the liquid product, it was concluded that phenol can be prepared by direct conversion of the catalytic optical disc particles, wherein the yield of phenol is 55%.

[0056] Example 3

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

[0058] Through qualitative and quantitative analysis of the liquid product, it was concluded that phenol can be prepared by direct conversion of the catalytic optical disc particles, wherein the yield of phenol is 85%.

[0059] Example 4

[0060] The CD was crushed, and then 0.6g of CD particles with a particle size of 4 to 200 mesh were weighed and added to a 50mL reactor. 10mL of water and 10mL of methanol were added as reaction solvents and 0.02g of 20K-CNT as catalyst, and magnetic stirring was used to mix them thoroughly. The reactor was sealed, and the gas in the reactor was replaced with nitrogen 5 times. Then, the reactor was filled with hydrogen to 4.0MPa, and the inlet and outlet were closed. The temperature was raised to 330℃ by electric heating under 1000rpm magnetic stirring, and maintained at this temperature for 420min. After the reaction was completed, stirring was stopped, and the reactor was cooled to room temperature with ice water. 10mL of the reaction solution was taken and 60mg of n-dodecane was added as an internal standard, and 10mL of ethyl acetate was added. The catalyst after the reaction was separated by centrifugation and further recycled.

[0061] Through qualitative and quantitative analysis of the liquid product, it was concluded that phenol can be prepared by direct conversion of the catalytic optical disc particles, with a phenol yield of 87%.

[0062] Example 5

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

[0064] Through qualitative and quantitative analysis of the liquid product, it was concluded that phenol can be prepared by direct conversion of the catalytic optical disc particles, wherein the yield of phenol is 88%.

[0065] Example 6

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

[0067] Through qualitative and quantitative analysis of the liquid product, it was concluded that phenol can be prepared by direct conversion of the catalytic optical disc particles, with a phenol yield of 71%.

[0068] Example 7

[0069] The preparation process described in Example 1 was repeated, except that the optical disk was replaced by a lampshade, and the main product obtained was phenol, wherein the yield of phenol was 85%.

[0070] Example 8

[0071] The preparation process described in Example 2 was repeated, except that the optical disk was replaced by a lampshade, and the main product obtained was phenol, wherein the yield of phenol was 51%.

[0072] Example 9

[0073] The preparation process described in Example 3 was repeated, except that the optical disk was replaced by a lampshade, and the main product obtained was phenol, wherein the yield of phenol was 82%.

[0074] Example 10

[0075] The preparation process described in Example 4 was repeated, except that the optical disk was replaced by a lampshade, and the main product obtained was phenol, wherein the yield of phenol was 75%.

[0076] Embodiment 11

[0077] The preparation process described in Example 5 was repeated, except that the optical disk was replaced by a lampshade, and the main product obtained was phenol, wherein the yield of phenol was 84%.

[0078] Example 12

[0079] The preparation process described in Example 6 was repeated, except that the optical disk was replaced by a lampshade, and the main product obtained was phenol, wherein the yield of phenol was 75%.

[0080] Example 13

[0081] The preparation process described in Example 1 was repeated, except that the optical disk was replaced by a polycarbonate plastic cup. The main product obtained was phenol, wherein the yield of phenol was 88%.

[0082] Embodiment 14

[0083] The preparation process described in Example 2 was repeated, except that the optical disk was replaced by a polycarbonate plastic cup. The main product obtained was phenol, wherein the yield of phenol was 58%.

[0084] Embodiment 15

[0085] The preparation process described in Example 3 was repeated, except that the optical disk was replaced by a polycarbonate plastic cup, and the main product obtained was phenol, wherein the yield of phenol was 79%.

[0086] Example 16

[0087] The preparation process described in Example 4 was repeated, except that the optical disk was replaced by a polycarbonate plastic cup, and the main product obtained was phenol, wherein the yield of phenol was 74%.

[0088] Embodiment 17

[0089] The preparation process described in Example 5 was repeated, except that the optical disk was replaced by a polycarbonate plastic cup, and the main product obtained was phenol, wherein the yield of phenol was 83%.

[0090] Embodiment 18

[0091] The preparation process described in Example 6 was repeated, except that the optical disk was replaced by a polycarbonate plastic cup, and the main product obtained was phenol, wherein the yield of phenol was 77%.

[0092] Embodiment 19

[0093] The preparation process described in Example 1 was repeated, except that the optical disk was replaced with a medical safety mask, and the main product obtained was phenol, wherein the yield of phenol was 78%.

[0094] Embodiment 20

[0095] The preparation process described in Example 2 was repeated, except that the optical disk was replaced by a medical safety mask, and the main product obtained was phenol, wherein the yield of phenol was 57%.

[0096] Embodiment 21

[0097] The preparation process described in Example 3 was repeated, except that the optical disk was replaced by a medical safety mask, and the main product obtained was phenol, wherein the yield of phenol was 86%.

[0098] Embodiment 22

[0099] The preparation process described in Example 4 was repeated, except that the optical disk was replaced by a medical safety mask, and the main product obtained was phenol, wherein the yield of phenol was 77%.

[0100] Embodiment 23

[0101] The preparation process described in Example 5 was repeated, except that the optical disk was replaced by a medical safety mask, and the main product obtained was phenol, wherein the yield of phenol was 87%.

[0102] Embodiment 24

[0103] The preparation process described in Example 6 was repeated, except that the optical disk was replaced by a medical safety mask, and the main product obtained was phenol, wherein the yield of phenol was 73%.

[0104] Embodiment 25

[0105] The preparation process described in Example 1 was repeated, except that the optical disc was replaced by an optical lens. The main product obtained was phenol, wherein the yield of phenol was 83%.

[0106] Embodiment 26

[0107] The preparation process described in Example 2 was repeated, except that the optical disc was replaced by an optical lens. The main product obtained was phenol, wherein the yield of phenol was 53%.

[0108] Embodiment 27

[0109] The preparation process described in Example 3 was repeated, except that the optical disc was replaced by an optical lens, and the main product obtained was phenol, wherein the yield of phenol was 83%.

[0110] Embodiment 28

[0111] The preparation process described in Example 4 was repeated, except that the optical disc was replaced by an optical lens, and the main product obtained was phenol, wherein the yield of phenol was 76%.

[0112] Embodiment 29

[0113] The preparation process described in Example 5 was repeated, except that the optical disc was replaced by an optical lens, and the main product obtained was phenol, wherein the yield of phenol was 80%.

[0114] Embodiment 30

[0115] The preparation process described in Example 6 was repeated, except that the optical disc was replaced by an optical lens, and the main product obtained was phenol, wherein the yield of phenol was 78%.

[0116] Embodiment 31

[0117] The preparation process described in Example 1 was repeated, except that the optical disk was replaced by a high-pressure syringe housing, and the main product obtained was phenol, wherein the yield of phenol was 83%.

[0118] Embodiment 32

[0119] The preparation process described in Example 2 was repeated, except that the optical disk was replaced by a high-pressure syringe housing, and the main product obtained was phenol, wherein the yield of phenol was 49%.

[0120] Embodiment 33

[0121] The preparation process described in Example 3 was repeated, except that the optical disk was replaced by a high-pressure syringe housing, and the main product obtained was phenol, wherein the yield of phenol was 78%.

[0122] Embodiment 34

[0123] The preparation process described in Example 4 was repeated, except that the optical disk was replaced by a high-pressure syringe housing, and the main product obtained was phenol, wherein the yield of phenol was 75%.

[0124] Embodiment 35

[0125] The preparation process described in Example 5 was repeated, except that the optical disk was replaced by a high-pressure syringe housing, and the main product obtained was phenol, wherein the yield of phenol was 83%.

[0126] Embodiment 36

[0127] The preparation process described in Example 6 was repeated, except that the optical disk was replaced by a high-pressure syringe housing, and the main product obtained was phenol, wherein the yield of phenol was 73%.

[0128] Embodiment 37

[0129] The preparation process described in Example 1 was repeated, except that the optical disk was replaced with a polycarbonate canopy, and the main product obtained was phenol, wherein the yield of phenol was 81%.

[0130] Embodiment 38

[0131] The preparation process described in Example 2 was repeated, except that the optical disk was replaced with a polycarbonate canopy, and the main product obtained was phenol, wherein the yield of phenol was 48%.

[0132] Embodiment 39

[0133] The preparation process described in Example 3 was repeated, except that the optical disk was replaced with a polycarbonate canopy, and the main product obtained was phenol, wherein the yield of phenol was 77%.

[0134] Embodiment 40

[0135] The preparation process described in Example 4 was repeated, except that the optical disk was replaced with a polycarbonate canopy, and the main product obtained was phenol, wherein the yield of phenol was 65%.

[0136] Embodiment 41

[0137] The preparation process described in Example 5 was repeated, except that the optical disk was replaced with a polycarbonate canopy, and the main product obtained was phenol, wherein the yield of phenol was 79%.

[0138] Embodiment 42

[0139] The preparation process described in Example 6 was repeated, except that the optical disk was replaced with a polycarbonate canopy, and the main product obtained was phenol, wherein the yield of phenol was 70%.

[0140] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for converting polycarbonate into phenol, characterized in that: The method comprises at least the following steps: (1) crushing polycarbonate waste; (2) mixing the crushed polycarbonate waste with water, methanol and a catalyst, and reacting them in a closed pressure vessel with an inert atmosphere; The catalyst is a supported potassium catalyst.

2. The method according to claim 1, characterized in that The supported potassium catalyst is at least one of K-TiO2, K-CeO2, K-CNT, K-CTF, K-Al2O3 or K-ZrO2; Preferably, the mass content of K element in the supported potassium catalyst is 5 to 40%; Preferably, the mass content of K element is 5 to 30%; More preferably, the mass content of K element is 5-20%.

3. The method according to claim 1, characterized in that In step (1), the pulverization is to process the polycarbonate waste into particles with a particle size of less than 1 cm; Preferably, the size of the particles is between 4 and 200 meshes.

4. The method according to claim 1, characterized in that In step (1), the polycarbonate waste is selected from at least one of optical disks, automobile lampshades, optical lenses, medical safety masks, high-pressure syringe housings, and polycarbonate canopies.

5. The method according to claim 1, characterized in that: In step (2), the volume of the water and methanol is 10 to 65% of the total volume of the pressure vessel; Preferably, the volume of the water and methanol is 20-50% of the total volume of the pressure vessel; Further preferably, the volume of water and methanol is 30-45% of the total volume of the pressure vessel; Preferably, the volume ratio of water to methanol is 20 to 0:1; More preferably, the volume ratio of water to methanol is 10 to 0:

1.

6. 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; Preferably, the amount of the crushed polycarbonate waste added is 1 to 15% of the mass of the water and methanol; Further preferably, the amount of the crushed polycarbonate waste added is 2-10% of the mass of the water and methanol.

7. The method according to claim 1, characterized in that In step (2), the amount of the catalyst added is 5 to 60% of the mass of the crushed polycarbonate waste; Preferably, the added amount of the catalyst is 5-30% of the mass of the pulverized polycarbonate waste.

8. The method according to claim 1, characterized in that In step (2), the reaction temperature is 150 to 350° C.; Preferably, the reaction temperature is 200-330°C; More preferably, the reaction temperature is 220-290°C.

9. The method according to claim 1, characterized in that: In step (2), the reaction time is 1 to 12 hours; Preferably, the reaction time is 2 to 10 hours; More preferably, the reaction time is 2 to 6 hours.

10. The method according to claim 1, characterized in that The method also includes the steps of separation and reuse of the catalyst.

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