Method for catalytically cracking plastic, cracking solution and application of cracking solution

Abstract

The invention relates to the field of waste plastic recovery, and discloses a plastic catalytic cracking method, a cracking solution and application thereof. The method comprises the following step: under an aerobic condition, carrying out catalytic cracking reaction on a mixture of a polyolefin-containing material, a titanium silicalite molecular sieve catalyst and water. The method has the advantages of high catalytic cracking efficiency and low cost, and can improve the yield of the long-chain dicarboxylic acid product.

Description

Technical Field

[0001] This invention relates to the field of waste plastic recycling, specifically to a method for catalytic pyrolysis of plastics, a pyrolysis solution, and its applications. Background Technology

[0002] Microplastics enter the human body through the ecosystem, posing a threat to human health. How to manage the large accumulation of waste plastics is a crucial issue. Traditional treatment methods include incineration and landfill. Incineration produces nitrogen oxides and fine inhalable particles, impacting air quality. Similarly, landfill requires a large soil area, has a slow degradation rate, and generates toxic substances for land and water resources. However, oxidation recycling can transform polyolefin plastics into high-value products such as polymerization intermediates, dicarboxylic acids, and raw materials for petrochemical and pharmaceutical reaction monomers. Based on environmental policies and economic feasibility principles, the value of oxidation recycling technology has attracted widespread attention worldwide.

[0003] Value-added recycling processes for oxidized plastics have economic value and promising applications. Recycling process reaction conditions are categorized into harsh and mild reactions. Harsh reactions generally require high temperature, high pressure, and strong catalysts, such as pyrolysis, solvation, hydrolysis, alcoholysis, hydrogenolysis, and microwave pyrolysis. Mild conditions involve low temperature and ambient pressure, with no or low catalyst loading, including photocatalysis, electrocatalysis, and biocatalysis. Furthermore, an increasing number of innovative technologies are being applied to the high-value recycling of plastics.

[0004] Taking polyolefin plastics as an example, polymers typically possess C-C single bonds. These bonds, due to their inherent properties, are relatively strong and not easily broken. This characteristic prevents the plastics from rapidly degrading on their own; therefore, the degradation of polyolefin plastics relies on catalytic hydrogenolysis. These methods are not widely used due to their high cost, energy consumption, and low added value of the reaction products. Therefore, exploring how to catalytically upgrade polyolefin waste into fuels and value-added chemicals has attracted considerable attention from researchers.

[0005] The inventors of this invention disclosed a low-temperature catalytic oxidative cracking and recycling method for high-value-added polyolefin plastics in their patent application (application number 202311114389.8). Using ZSM-5 molecular sieves with a Si / Al ratio of no more than 70 as a catalyst, the method primarily converts polyolefin plastics into liquid long-chain dicarboxylic acids. The yield is consistently above 70%, and overall energy consumption is reduced, meeting the industrial-scale recycling needs for high-value-added polyolefin plastics and providing an effective strategy for achieving economically sustainable recycling of polyolefins. However, a drawback is that the ZSM-5 zeolite catalyst is prone to carbon buildup during high-temperature reactions, leading to catalyst deactivation and consequently affecting catalytic cracking efficiency and lifespan.

[0006] Therefore, there is an urgent need to provide a method for catalytic cracking of plastics that has high catalytic cracking efficiency and can increase the yield of long-chain dicarboxylic acids in the cracking products. Summary of the Invention

[0007] The purpose of this invention is to overcome the problems of low catalytic cracking efficiency, high cost, and low added value of reaction products in the existing catalytic cracking of plastics, and to provide a method, cracking liquid and its application for catalytic cracking of polyolefin plastics. This method has high catalytic cracking efficiency, low cost and can increase the yield of long-chain dicarboxylic acids in the product.

[0008] The first aspect of the present invention provides a method for catalytic cracking of plastics, comprising the following steps: catalytic cracking reaction of a mixture of polyolefin-containing material, titanium-silicon molecular sieve catalyst and water under aerobic conditions.

[0009] Preferably, in the titanium-silicon molecular sieve catalyst, the titanium content is 1.7-1.8% by mass, and the silicon content is 18.2-18.5% by mass.

[0010] Preferably, the specific surface area of ​​the titanium-silicon molecular sieve catalyst is 400-500 m². 2 / g, the pore size of the molecular sieve is 0.3-0.5nm.

[0011] Preferably, the catalytic cracking reaction includes:

[0012] S1. A catalytic cracking reaction I is carried out on the mixture of the polyolefin-containing material, the titanium-silicon molecular sieve catalyst, and the water;

[0013] S2. The mixture I obtained from the catalytic cracking reaction I is subjected to catalytic cracking reaction II;

[0014] S3. The mixture II obtained from the catalytic cracking reaction II is subjected to catalytic cracking reaction III.

[0015] Preferably, in step S1, the conditions for the catalytic cracking reaction I include at least: a pressure of 1.5-2.0 MPa, a temperature of 140-145 °C, and a time of 1-2 h.

[0016] Preferably, in step S2, the conditions for the catalytic cracking reaction II include at least: a pressure of 1.5-2.0 MPa, a temperature of 180-220°C, and a time of 1-3 h.

[0017] Preferably, in step S3, the conditions for the catalytic cracking reaction III include at least: a pressure of 1.5-2.0 MPa, a temperature of 140-145 °C, and a time of 5-12 h.

[0018] Preferably, the weight ratio of the titanium-silicon molecular sieve catalyst to the polyolefin-containing material is 0.2-0.6:1.

[0019] Preferably, the method further includes separating the products of the catalytic cracking reaction to obtain an oily liquid product.

[0020] Preferably, the weight ratio of the oily liquid product to the polyolefin-containing material is 0.50-0.94:1.

[0021] Preferably, the oily liquid product contains C5-C. 20 Aliphatic dicarboxylic acids.

[0022] Preferably, the polyolefin-containing material is selected from polyethylene plastics and / or polypropylene plastics.

[0023] Preferably, the polyethylene plastic is high-density polyethylene and / or low-density polyethylene.

[0024] A second aspect of the present invention provides a pyrolysis solution prepared by the method described in the first aspect above.

[0025] Preferably, the lysis solution contains C5-C 20 Aliphatic dicarboxylic acids.

[0026] A third aspect of the present invention provides the application of the lysis solution described in the second aspect above in the preparation of surfactants.

[0027] The beneficial effects of the present invention through the above technical solution are as follows:

[0028] The catalytic cracking method for plastics provided by this invention utilizes titanium-silicon molecular sieves, which, compared to other catalysts, do not require precious metal loading, are inexpensive, and possess high catalytic activity. Under mild reaction conditions, using water as the reaction medium, it catalyzes the cracking of polyolefin-containing materials, converting them into long-chain dicarboxylic acids. These long-chain dicarboxylic acids have high added value, and the yield of obtained long-chain dicarboxylic acids is high. This method provides a new and effective strategy for the economical recycling of polyethylene, meeting the industrial recycling needs for high-value-added plastics such as HDPE. Moreover, this catalytic cracking method for plastics is simple, low-cost, and offers significant economic benefits.

[0029] Furthermore, the catalytic cracking reaction of the mixture of polyolefin-containing materials, titanium-silicon molecular sieve catalyst, and water includes catalytic cracking reaction I, catalytic cracking reaction II, and catalytic cracking reaction III. A temperature gradient that first increases and then decreases is set to reduce the heat consumption of the reaction. Through the synergistic effect of reaction temperature and reaction time, the efficiency of the catalytic cracking reaction is further improved, thereby further increasing the yield of long-chain dicarboxylic acids. Moreover, the generation of coke on the catalyst surface and energy consumption are reduced.

[0030] Other advantages of the present invention and the technical effects of preferred embodiments will be further described in the following detailed description. Attached Figure Description

[0031] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0032] Figure 1 This is a schematic diagram of the catalytic cracking process of plastics provided in the embodiments of the present invention;

[0033] Figure 2 These are the XRD patterns of the TS-1 catalyst in Examples 1-21 and Comparative Example 2 of this invention;

[0034] Figure 3 The accompanying drawings show the nitrogen adsorption and desorption of the TS-1 catalyst in Examples 1-21 and Comparative Example 2 of this invention;

[0035] Figure 4 These are the infrared spectra of the brownish-yellow oily liquids in Example 2 and Comparative Example 1 of the present invention;

[0036] Figure 5 This is the 1H NMR spectrum of the brownish-yellow oily liquid obtained in Example 2 of this invention;

[0037] Figure 6 This is a high-resolution mass spectrum of the brownish-yellow oily liquid obtained in Example 2 of the present invention;

[0038] Figure 7 This is a graph showing the relationship between the yield of the brownish-yellow oily liquid obtained in Examples 1-3 of this invention and the temperature of catalytic cracking reaction II. Detailed Implementation

[0039] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0040] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0041] The first aspect of the present invention provides a method for catalytic cracking of plastics, characterized by comprising the following steps: mixing polyolefin plastics, titanium-silicon molecular sieve catalysts and water and then carrying out a catalytic cracking reaction.

[0042] During their research, the inventors discovered that, compared to other catalysts, titanium-silicon molecular sieve catalysts do not require precious metal loading, are inexpensive, and possess high catalytic activity. They can catalyze the cracking reaction of polyolefin-containing materials into long-chain dicarboxylic acids under mild reaction conditions using water as the reaction medium. These long-chain dicarboxylic acids have high added value, and the yield of obtained long-chain dicarboxylic acids is high. This method provides a new and effective strategy for the economical recycling of polyethylene, meeting the industrial recycling needs for high-value-added plastics such as HDPE. Furthermore, the catalytic cracking method for plastics is simple, low-cost, and offers significant economic benefits.

[0043] In this invention, the titanium-silicon molecular sieve catalyst (TS-1 molecular sieve catalyst) refers to a titanium-silicon molecular sieve in which Ti atoms partially replace aluminum atoms. It belongs to the ZSM-5 series of zeolite molecular sieves, is orthorhombic, and is an isomorphous substitution derivative of pure silica zeolite, possessing an MFI (mobil five in structure) topology. MFI molecular sieves have a porous structure. The catalytic performance of the titanium-silicon molecular sieve catalyst is mainly determined by the active titanium catalytic centers, exhibiting excellent catalytic performance.

[0044] In this invention, a schematic diagram of the catalytic cracking process of plastics is shown below. Figure 1 As shown.

[0045] According to the present invention, preferably, the titanium content in the titanium-silicon molecular sieve catalyst is 1.7-1.8% by mass, and the silicon content is 18.2-18.5% by mass. The inventors have found that, under this preferred embodiment, the synergistic effect of titanium and silicon in a specific ratio can improve the catalytic activity of the titanium-silicon molecular sieve catalyst, thereby improving the reaction efficiency of catalytic cracking of polyolefin-containing materials.

[0046] In this invention, the specific surface area of ​​the titanium-silicon molecular sieve catalyst is 400-500 m². 2 / g, the molecular sieve has a pore size of 0.3-0.5nm. The inventors have discovered that titanium-silicon molecular sieve catalysts within the above specific surface area range exhibit better catalytic activity and can further improve the reaction efficiency of catalytic cracking of polyolefin-containing materials.

[0047] In this invention, the titanium-silicon molecular sieve catalyst can be obtained commercially or prepared in-house.

[0048] In this invention, to further improve the reaction efficiency and product yield of the catalytic cracking reaction, preferably, the catalytic cracking reaction includes:

[0049] S1. A catalytic cracking reaction I is carried out on the mixture of the polyolefin-containing material, the titanium-silicon molecular sieve catalyst, and the water;

[0050] S2. The mixture I obtained from the catalytic cracking reaction I is subjected to catalytic cracking reaction II;

[0051] S3. The mixture II obtained from the catalytic cracking reaction II is subjected to catalytic cracking reaction III.

[0052] The inventors discovered that, under this preferred embodiment, setting catalytic cracking reaction I, catalytic cracking reaction II, and catalytic cracking reaction III in stages with different temperature gradients reduces the heat consumption of the reaction, improves the efficiency of the catalytic cracking reaction, thereby increasing the yield of long-chain dicarboxylic acids, and also reduces the generation of coke on the catalyst surface and energy consumption.

[0053] According to the present invention, in order to further improve the reaction efficiency of catalytic cracking reaction I and reduce the reaction heat energy consumption, preferably, in step S1, the conditions of catalytic cracking reaction I include at least the following: pressure of 1.5-2.0 MPa, specifically 1.5 MPa, 1.8 MPa, 2.0 MPa, or any value between the two aforementioned values; temperature of 140-145°C, specifically 140°C, 141°C, 142°C, 143°C, 144°C, 145°C, or any value between the two aforementioned values; and time of 1-2 h, specifically 1 h, 1.5 h, 2 h, or any value between the two aforementioned values.

[0054] In step S1 of this invention, before the start of catalytic cracking reaction I, the mixture of polyolefin-containing material, titanium-silicon molecular sieve catalyst, and water is heated from room temperature to 140-145°C. There is no particular limitation on the heating rate, but it is preferably 4-5°C / min.

[0055] According to the present invention, in order to further improve the reaction efficiency of catalytic cracking reaction II and reduce the reaction heat consumption, preferably, in step S2, the conditions of catalytic cracking reaction II include at least: pressure of 1.5-2.0 MPa, specifically 1.5 MPa, 1.8 MPa, 2.0 MPa, or any value between the two aforementioned values; temperature of 180-220°C, specifically 180°C, 190°C, 200°C, 210°C, 220°C; and time of 1-3 h, specifically 1 h, 2 h, 3 h, or any value between the two aforementioned values.

[0056] In step S2 of the present invention, before the catalytic cracking reaction II begins, the mixture I is heated to 180-220°C.

[0057] According to the present invention, in order to further improve the reaction efficiency of catalytic cracking reaction III and reduce the reaction heat energy consumption, preferably, in step S3, the conditions of catalytic cracking reaction III include at least: pressure of 1.5-2.0 MPa, specifically 1.5 MPa, 1.8 MPa, 2.0 MPa, or any value between the two aforementioned values; temperature of 140℃-145℃, specifically 140℃, 141℃, 142℃, 143℃, 144℃, 145℃, or any value between the two aforementioned values; and time of 5-12 h, specifically 5 h, 8 h, 10 h, 12 h, or any value between the two aforementioned values.

[0058] In step S3 of this invention, after the catalytic cracking reaction III is completed, the mixture III obtained from the catalytic cracking reaction III is naturally cooled to room temperature.

[0059] In this invention, the catalytic cracking reaction can be carried out under stirring conditions, and there are no special requirements for the stirring speed, but it is preferably 300-400 rpm.

[0060] Through the synergistic effect of the aforementioned catalytic cracking reactions I, II, and III, under specific reaction temperatures and times, not only can the yield of long-chain dicarboxylic acids obtained from the catalytic cracking of polyolefin-containing materials be increased, but also the production and energy consumption of coke on the catalyst surface can be reduced. Furthermore, by simultaneously obtaining long-chain dicarboxylic acid yields, the staged catalytic cracking reactions not only reduce the overall catalytic cracking reaction time but also alleviate catalyst coking, thereby improving the efficiency and yield of the catalytic cracking reaction.

[0061] According to the present invention, in order to further improve the reaction efficiency and yield of the catalytic cracking reaction, preferably, the weight ratio of the titanium-silicon molecular sieve catalyst and the polyolefin-containing material is 0.2-0.6:1, specifically 0.2:1, 0.4:1, 0.6:1, or any value between the two aforementioned values.

[0062] According to the present invention, in order to further improve the yield and purity of long-chain dicarboxylic acids, preferably, the method further includes: separating the product of the catalytic cracking reaction to obtain an oily liquid product.

[0063] In this invention, separation can be performed using conventional separation methods selected in the art, such as filtration, centrifugation, and rotary evaporation.

[0064] In this invention, after the catalytic cracking reaction is completed, the reactor contains gas, solid, and liquid, and the substances in the reactor can be post-processed. For example, a gas bag can be used to collect the gas generated in the reactor; the reactor can be cleaned with a solvent, and the mixture can be filtered to obtain solid and liquid, and the liquid can be separated to obtain an oily liquid product.

[0065] In this invention, the solvent for cleaning the reactor can be ethanol and / or dichloromethane, preferably ethanol and dichloromethane.

[0066] For example, the process of separating the products of a catalytic cracking reaction to obtain an oily liquid product includes: collecting the gas generated by the reaction with a gas bag, washing the reactor with a mixed solution of ethanol and dichloromethane, collecting the filtered solid and liquid, and obtaining the oily liquid product by a rotary evaporator.

[0067] According to the present invention, the weight ratio of the oily liquid product to the polyolefin-containing material is 0.50-0.94:1, specifically 0.50:1, 0.70:1, 0.94:1, or any value between the two aforementioned values. The method provided by the present invention can achieve a high yield of long-chain dicarboxylic acids, resulting in significant economic benefits.

[0068] According to the present invention, preferably, the oily liquid product contains C5-C. 20 Aliphatic dicarboxylic acids.

[0069] According to the present invention, in order to further improve the catalytic cracking effect of polyolefin-containing materials, preferably, the polyolefin-containing materials are selected from polyethylene plastics and / or polypropylene plastics. The polyolefin-containing materials can be polyethylene plastics, polypropylene plastics, or mixtures of polyethylene and polypropylene plastics. The polyethylene plastics can be polyethylene plastic powder and plastic products, and the polypropylene plastics can be polypropylene plastic powder and plastic products.

[0070] According to the present invention, preferably, the polyethylene plastic is high-density polyethylene and / or low-density polyethylene. Exemplarily, the polyethylene plastic is high-density polyethylene (HDPE), low-density polyethylene (LDPE), or linear low-density polyethylene (LLDPE).

[0071] In this invention, all of the above-mentioned substances can be obtained commercially.

[0072] According to a particularly preferred embodiment of the present invention, a method for catalytically pyrolyzing plastics is provided, comprising the following steps:

[0073] S1. Under aerobic conditions, a mixture of polyolefin-containing material, titanium-silicon molecular sieve catalyst, and water is reacted at a pressure of 1.5-2.0 MPa and a temperature of 140-145℃ to obtain mixture I.

[0074] S2. Mixture I is reacted at a pressure of 1.5-2.0 MPa and a temperature of 180-220℃ for 1-3 hours to obtain mixture II;

[0075] S3. Mixture II is reacted at a pressure of 1.5-2.0 MPa and a temperature of 140-145℃ for 5-12 hours to obtain mixture III;

[0076] S4. Separate mixture III to obtain an oily liquid product;

[0077] In the titanium-silicon molecular sieve catalyst, the titanium content is 1.7-1.8% by mass, and the silicon content is 18.2-18.5% by mass; the specific surface area of ​​the titanium-silicon molecular sieve catalyst is 400-500 m². 2 / g, the pore size of the molecular sieve is 0.3-0.5nm; the weight ratio of titanium-silicon molecular sieve catalyst and polyolefin-containing material is 0.2-0.6:1.

[0078] The present invention will be described in detail below through embodiments.

[0079] In the following examples, the titanium-silicon molecular sieve catalyst (TS-1 catalyst) was purchased from Nanjing Xianfeng Nanomaterials Technology Co., Ltd., model XFF08; unless otherwise specified, all other raw materials or reagents are conventional commercial products.

[0080] Example 1

[0081] (1) 0.2g of high-density polyethylene (HDPE) plastic powder and 0.1g of TS-1 catalyst (in which the contents of titanium, silicon and aluminum are 1.7623% by mass, 18.2426% by mass and 0.0048% by mass, respectively, and the specific surface area is 443.6m²) were mixed. 2 / g, the molecular sieve with a pore size of 0.39nm (purchased from Nanjing Xianfeng Nanotechnology Co., Ltd., model XFF08) and 15mL of water were added to a quartz tube reactor to obtain a dispersion;

[0082] (2) Transfer the quartz tube reactor to a high-pressure reactor, fill it with high-purity air at a pressure of 1.5 MPa, stir at 300 rpm, set a temperature gradient to carry out catalytic cracking reaction, raise the temperature to 140°C at a set heating rate of 5°C / min and keep it at a constant temperature for 1 h; raise the temperature again to 180°C and keep it at 2 h; then lower the temperature to 140°C to carry out catalytic cracking reaction, and set the reaction time to 9 h, so that the HDPE dispersed in the water is converted into liquid long-chain dicarboxylic acid in three steps;

[0083] (3) After the reaction is completed within the set time, the reactor is allowed to cool to room temperature naturally and then post-processing is performed: the gas generated by the reaction is collected with a gas bag, the reactor is then cleaned with a mixed solution of ethanol and dichloromethane, the filtered solid and liquid are collected, and a brownish-yellow oily liquid is obtained by rotary evaporator. The liquid is detected to be a long-chain dicarboxylic acid.

[0084] Example 2

[0085] (1) 0.2g of high-density polyethylene (HDPE) plastic powder and 0.1g of TS-1 catalyst (in which the contents of titanium, silicon and aluminum are 1.7623% by mass, 18.2426% by mass and 0.0048% by mass, respectively, and the specific surface area is 443.6m²) were mixed. 2 / g, the molecular sieve with a pore size of 0.39nm (purchased from Nanjing Xianfeng Nanomaterials Technology Co., Ltd., model XFF08) and 15mL of water were added to a quartz tube reactor to obtain a dispersion;

[0086] (2) Transfer the quartz tube reactor to a high-pressure reactor, fill it with high-purity air at a pressure of 1.5 MPa, stir at 300 rpm, set a temperature gradient to carry out the catalytic cracking reaction, raise the temperature to 140°C at a set heating rate of 5°C / min and keep it at a constant temperature for 1 h; raise the temperature again to 200°C and keep it at 2 h; then lower the temperature to 140°C to carry out the catalytic cracking reaction, and set the reaction time to 9 h, so that the HDPE dispersed in the water is converted into liquid long-chain dicarboxylic acid in three steps;

[0087] (3) After the reaction is completed within the set time, the reactor is allowed to cool to room temperature naturally and then post-processing is performed: the gas generated by the reaction is collected with a gas bag, the reactor is then cleaned with a mixed solution of ethanol and dichloromethane, the filtered solid and liquid are collected, and a brownish-yellow oily liquid is obtained by rotary evaporator. The liquid is detected to be a long-chain dicarboxylic acid.

[0088] Example 3

[0089] (1) 0.2g of high-density polyethylene (HDPE) plastic powder and 0.1g of TS-1 catalyst (in which the contents of titanium, silicon and aluminum are 1.7623% by mass, 18.2426% by mass and 0.0048% by mass, respectively, and the specific surface area is 443.6m²) were mixed. 2 / g, the molecular sieve with a pore size of 0.39nm (purchased from Nanjing Xianfeng Nanomaterials Technology Co., Ltd., model XFF08) and 15mL of water were added to a quartz tube reactor to obtain a dispersion;

[0090] (2) Transfer the quartz tube reactor to a high-pressure reactor, fill it with high-purity air at a pressure of 1.5 MPa, stir at 300 rpm, set a temperature gradient to carry out the catalytic cracking reaction, raise the temperature to 140°C at a set heating rate of 5°C / min and hold it at 1h; raise the temperature again to 220°C and hold it for 2h; then lower the temperature to 140°C to carry out the catalytic cracking reaction, and set the reaction time to 9h, so that the HDPE dispersed in the water is converted into liquid long-chain dicarboxylic acid in three steps;

[0091] (3) After the reaction is completed within the set time, the reactor is allowed to cool to room temperature naturally and then post-processing is performed: the gas generated by the reaction is collected with a gas bag, the reactor is then cleaned with a mixed solution of ethanol and dichloromethane, the filtered solid and liquid are collected, and a brownish-yellow oily liquid is obtained by rotary evaporator. The liquid is detected to be a long-chain dicarboxylic acid.

[0092] Example 4

[0093] (1) 0.2g of high-density polyethylene (HDPE) plastic powder and 0.05g of TS-1 catalyst (in which the contents of titanium, silicon and aluminum are 1.7623% by mass, 18.2426% by mass and 0.0048% by mass, respectively, and the specific surface area is 443.6m²) were mixed. 2 / g, the molecular sieve with a pore size of 0.39nm (purchased from Nanjing Xianfeng Nanotechnology Co., Ltd., model XFF08) and 15mL of water were added to a quartz tube reactor to obtain a dispersion;

[0094] (2) Transfer the quartz tube reactor to a high-pressure reactor, fill it with high-purity air at a pressure of 1.5 MPa, stir at 300 rpm, set a temperature gradient to carry out the catalytic cracking reaction, raise the temperature to 140°C at a set heating rate of 5°C / min and keep it at a constant temperature for 1 hour; raise the temperature again to 200°C and keep it at 1 hour; then lower the temperature to 140°C to carry out the catalytic cracking reaction, and set the reaction time to 10 hours, so that the HDPE dispersed in the water is converted into liquid long-chain dicarboxylic acid in three steps.

[0095] (3) After the reaction is completed within the set time, the reactor is allowed to cool to room temperature naturally and then post-processing is performed: the gas generated by the reaction is collected with a gas bag, the reactor is then cleaned with a mixed solution of ethanol and dichloromethane, the filtered solid and liquid are collected, and a brownish-yellow oily liquid is obtained by rotary evaporator. The liquid is detected to be a long-chain dicarboxylic acid.

[0096] Example 5

[0097] (1) 0.2g of high-density polyethylene (HDPE) plastic powder and 0.1g of TS-1 catalyst (in which the contents of titanium, silicon and aluminum are 1.7623% by mass, 18.2426% by mass and 0.0048% by mass, respectively, and the specific surface area is 443.6m²) were mixed. 2 / g, the molecular sieve with a pore size of 0.39nm (purchased from Nanjing Xianfeng Nanomaterials Technology Co., Ltd., model XFF08) and 15mL of water were added to a quartz tube reactor to obtain a dispersion;

[0098] (2) Transfer the quartz tube reactor to a high-pressure reactor, fill it with high-purity air at a pressure of 1.5 MPa, stir at 300 rpm, set a temperature gradient to carry out the catalytic cracking reaction, raise the temperature to 140°C at a set heating rate of 5°C / min and keep it at a constant temperature for 1 h; raise the temperature again to 200°C and keep it at 3 h; then lower the temperature to 140°C to carry out the catalytic cracking reaction, and set the reaction time to 8 h, so that the HDPE dispersed in the water is converted into liquid long-chain dicarboxylic acid in three steps;

[0099] (3) After the reaction is completed within the set time, the reactor is allowed to cool to room temperature naturally and then post-processing is performed: the gas generated by the reaction is collected with a gas bag, the reactor is then cleaned with a mixed solution of ethanol and dichloromethane, the filtered solid and liquid are collected, and a brownish-yellow oily liquid is obtained by rotary evaporator. The liquid is detected to be a long-chain dicarboxylic acid.

[0100] Example 6

[0101] (1) 0.2g of high-density polyethylene (HDPE) plastic powder and 0.1g of TS-1 catalyst (in which the contents of titanium, silicon and aluminum are 1.7623% by mass, 18.2426% by mass and 0.0048% by mass, respectively, and the specific surface area is 443.6m²) were mixed. 2 / g, the molecular sieve with a pore size of 0.39nm (purchased from Nanjing Xianfeng Nanomaterials Technology Co., Ltd., model XFF08) and 15mL of water were added to a quartz tube reactor to obtain a dispersion;

[0102] (2) Transfer the quartz tube reactor to a high-pressure reactor, fill it with high-purity air at a pressure of 1.5 MPa, stir at 300 rpm, set a temperature gradient to carry out the catalytic cracking reaction, raise the temperature to 140°C at a set heating rate of 5°C / min and keep it at a constant temperature for 1 h; raise the temperature again to 200°C and keep it at 2 h; then lower the temperature to 140°C to carry out the catalytic cracking reaction, and set the reaction time to 10 h, so that the HDPE dispersed in the water is converted into liquid long-chain dicarboxylic acid in three steps;

[0103] (3) After the reaction is completed within the set time, the reactor is allowed to cool to room temperature naturally and then post-processing is performed: the gas generated by the reaction is collected with a gas bag, the reactor is then cleaned with a mixed solution of ethanol and dichloromethane, the filtered solid and liquid are collected, and a brownish-yellow oily liquid is obtained by rotary evaporator. The liquid is detected to be a long-chain dicarboxylic acid.

[0104] Example 7

[0105] (1) 0.2g of high-density polyethylene (HDPE) plastic powder and 0.1g of TS-1 catalyst (in which the contents of titanium, silicon and aluminum are 1.7623% by mass, 18.2426% by mass and 0.0048% by mass, respectively, and the specific surface area is 443.6m²) were mixed. 2 / g, the molecular sieve with a pore size of 0.39nm (purchased from Nanjing Xianfeng Nanomaterials Technology Co., Ltd., model XFF08) and 15mL of water were added to a quartz tube reactor to obtain a dispersion;

[0106] (2) Transfer the quartz tube reactor to a high-pressure reactor, fill it with high-purity air at a pressure of 1.5 MPa, stir at 300 rpm, set a temperature gradient to carry out the catalytic cracking reaction, raise the temperature to 140°C at a set heating rate of 5°C / min and keep it at a constant temperature for 1 h; raise the temperature again to 200°C and keep it at 2 h; then lower the temperature to 140°C to carry out the catalytic cracking reaction, and set the reaction time to 11 h, so that the HDPE dispersed in the water is converted into liquid long-chain dicarboxylic acid in three steps;

[0107] (3) After the reaction is completed within the set time, the reactor is allowed to cool to room temperature naturally and then post-processing is performed: the gas generated by the reaction is collected with a gas bag, the reactor is then cleaned with a mixed solution of ethanol and dichloromethane, the filtered solid and liquid are collected, and a brownish-yellow oily liquid is obtained by rotary evaporator. The liquid is detected to be a long-chain dicarboxylic acid.

[0108] Example 8

[0109] (1) 0.2g of high-density polyethylene (HDPE) plastic powder and 0.1g of TS-1 catalyst (in which the contents of titanium, silicon and aluminum are 1.7623% by mass, 18.2426% by mass and 0.0048% by mass, respectively, and the specific surface area is 443.6m²) were mixed. 2 / g, the molecular sieve with a pore size of 0.39nm (purchased from Nanjing Xianfeng Nanomaterials Technology Co., Ltd., model XFF08) and 15mL of water were added to a quartz tube reactor to obtain a dispersion;

[0110] (2) Transfer the quartz tube reactor to a high-pressure reactor, fill it with high-purity air at a pressure of 1.5 MPa, stir at 300 rpm, set a temperature gradient to carry out the catalytic cracking reaction, raise the temperature to 140°C at a set heating rate of 5°C / min and keep it at a constant temperature for 1 h; raise the temperature again to 200°C and keep it at 2 h; then lower the temperature to 140°C to carry out the catalytic cracking reaction, and set the reaction time to 8 h, so that the HDPE dispersed in the water is converted into liquid long-chain dicarboxylic acid in three steps;

[0111] (3) After the reaction is completed within the set time, the reactor is allowed to cool to room temperature naturally and then post-processing is performed: the gas generated by the reaction is collected with a gas bag, the reactor is then cleaned with a mixed solution of ethanol and dichloromethane, the filtered solid and liquid are collected, and a brownish-yellow oily liquid is obtained by rotary evaporator. The liquid is detected to be a long-chain dicarboxylic acid.

[0112] Example 9

[0113] (1) 0.2g of high-density polyethylene (HDPE) plastic powder and 0.1g of TS-1 catalyst (in which the contents of titanium, silicon and aluminum are 1.7623% by mass, 18.2426% by mass and 0.0048% by mass, respectively, and the specific surface area is 443.6m²) were mixed. 2 / g, the molecular sieve with a pore size of 0.39nm (purchased from Nanjing Xianfeng Nanomaterials Technology Co., Ltd., model XFF08) and 15mL of water were added to a quartz tube reactor to obtain a dispersion;

[0114] (2) Transfer the quartz tube reactor to a high-pressure reactor, fill it with high-purity air at a pressure of 1.5 MPa, stir at 300 rpm, set a temperature gradient to carry out the catalytic cracking reaction, raise the temperature to 140°C at a set heating rate of 5°C / min and keep it at a constant temperature for 1 h; raise the temperature again to 200°C and keep it at 2 h; then lower the temperature to 140°C to carry out the catalytic cracking reaction, and set the reaction time to 7 h, so that the HDPE dispersed in the water is converted into liquid long-chain dicarboxylic acid in three steps;

[0115] (3) After the reaction is completed within the set time, the reactor is allowed to cool to room temperature naturally and then post-processing is performed: the gas generated by the reaction is collected with a gas bag, the reactor is then cleaned with a mixed solution of ethanol and dichloromethane, the filtered solid and liquid are collected, and a brownish-yellow oily liquid is obtained by rotary evaporator. The liquid is detected to be a long-chain dicarboxylic acid.

[0116] Example 10

[0117] (1) 0.2g of high-density polyethylene (HDPE) plastic powder and 0.1g of TS-1 catalyst (in which the contents of titanium, silicon and aluminum are 1.7623% by mass, 18.2426% by mass and 0.0048% by mass, respectively, and the specific surface area is 443.6m²) were mixed. 2 / g, the molecular sieve with a pore size of 0.39nm (purchased from Nanjing Xianfeng Nanomaterials Technology Co., Ltd., model XFF08) and 15mL of water were added to a quartz tube reactor to obtain a dispersion;

[0118] (2) Transfer the quartz tube reactor to a high-pressure reactor, fill it with high-purity air at a pressure of 1.5 MPa, stir at 300 rpm, set a temperature gradient to carry out the catalytic cracking reaction, raise the temperature to 140°C at a set heating rate of 5°C / min and keep it at a constant temperature for 1 h; raise the temperature again to 200°C and keep it at 2 h; then lower the temperature to 140°C to carry out the catalytic cracking reaction, and set the reaction time to 6 h, so that the HDPE dispersed in the water is converted into liquid long-chain dicarboxylic acid in three steps;

[0119] (3) After the reaction is completed within the set time, the reactor is allowed to cool to room temperature naturally and then post-processing is performed: the gas generated by the reaction is collected with a gas bag, the reactor is then cleaned with a mixed solution of ethanol and dichloromethane, the filtered solid and liquid are collected, and a brownish-yellow oily liquid is obtained by rotary evaporator. The liquid is detected to be a long-chain dicarboxylic acid.

[0120] Example 11

[0121] (1) 0.2g of high-density polyethylene (HDPE) plastic powder and 0.1g of TS-1 catalyst (in which the contents of titanium, silicon and aluminum are 1.7623% by mass, 18.2426% by mass and 0.0048% by mass, respectively, and the specific surface area is 443.6m²) were mixed. 2 / g, the molecular sieve with a pore size of 0.39nm (purchased from Nanjing Xianfeng Nanomaterials Technology Co., Ltd., model XFF08) and 15mL of water were added to a quartz tube reactor to obtain a dispersion;

[0122] (2) Transfer the quartz tube reactor to a high-pressure reactor, fill it with high-purity air at a pressure of 1.5 MPa, stir at 300 rpm, set a temperature gradient to carry out the catalytic cracking reaction, raise the temperature to 140°C at a set heating rate of 5°C / min and keep it at a constant temperature for 1 h; raise the temperature again to 200°C and keep it at 2 h; then lower the temperature to 140°C to carry out the catalytic cracking reaction, and set the reaction time to 5 h, so that the HDPE dispersed in the water is converted into liquid long-chain dicarboxylic acid in three steps;

[0123] (3) After the reaction is completed within the set time, the reactor is allowed to cool to room temperature naturally and then post-processing is performed: the gas generated by the reaction is collected with a gas bag, the reactor is then cleaned with a mixed solution of ethanol and dichloromethane, the filtered solid and liquid are collected, and a brownish-yellow oily liquid is obtained by rotary evaporator. The liquid is detected to be a long-chain dicarboxylic acid.

[0124] Example 12

[0125] (1) 0.2g of polypropylene (PP) plastic powder and 0.1g of TS-1 catalyst (in which the contents of titanium, silicon and aluminum are 1.7623% by mass, 18.2426% by mass and 0.0048% by mass, respectively, and the specific surface area is 443.6m²) were mixed. 2 / g, the molecular sieve with a pore size of 0.39nm (purchased from Nanjing Xianfeng Nanomaterials Technology Co., Ltd., model XFF08) and 15mL of water were added to a quartz tube reactor to obtain a dispersion;

[0126] (2) Transfer the quartz tube reactor to a high-pressure reactor, fill it with high-purity air at a pressure of 1.5 MPa, stir at 300 rpm, set a temperature gradient to carry out catalytic cracking reaction, raise the temperature to 140°C at a set heating rate of 5°C / min and keep it at a constant temperature for 1 h; raise the temperature again to 200°C and keep it at 2 h; then lower the temperature to 140°C to carry out catalytic cracking reaction, and set the reaction time to 9 h, so that the PP dispersed in the water is converted into liquid long-chain dicarboxylic acid in three steps;

[0127] (3) After the reaction is completed within the set time, the reactor is allowed to cool to room temperature naturally and then post-processing is performed: the gas generated by the reaction is collected with a gas bag, the reactor is then cleaned with a mixed solution of ethanol and dichloromethane, the filtered solid and liquid are collected, and a brownish-yellow oily liquid is obtained by rotary evaporator. The liquid is detected to be a long-chain dicarboxylic acid.

[0128] Example 13

[0129] (1) 0.2g of linear low-density polyethylene (LLDPE) powder and 0.1g of TS-1 catalyst (the catalyst contains 1.7623% by mass, 18.2426% by mass, and 0.0048% by mass of titanium, silicon, and aluminum, respectively, and has a specific surface area of ​​443.6m²) were mixed.2 / g, the molecular sieve with a pore size of 0.39nm (purchased from Nanjing Xianfeng Nanomaterials Technology Co., Ltd., model XFF08) and 15mL of water were added to a quartz tube reactor to obtain a dispersion;

[0130] (2) Transfer the quartz tube reactor to a high-pressure reactor, fill it with high-purity air at a pressure of 1.5 MPa, stir at 300 rpm, set a temperature gradient to carry out the catalytic cracking reaction, raise the temperature to 140°C at a set heating rate of 5°C / min and hold it at 1h; raise the temperature again to 200°C and hold it for 2h; then lower the temperature to 140°C to carry out the catalytic cracking reaction, and set the reaction time to 9h, so that the LLDPE dispersed in the water is converted into liquid long-chain dicarboxylic acid in three steps;

[0131] (3) After the reaction is completed within the set time, the reactor is allowed to cool to room temperature naturally and then post-processing is performed: the gas generated by the reaction is collected with a gas bag, the reactor is then cleaned with a mixed solution of ethanol and dichloromethane, the filtered solid and liquid are collected, and a brownish-yellow oily liquid is obtained by rotary evaporator. The liquid is detected to be a long-chain dicarboxylic acid.

[0132] Example 14

[0133] (1) 0.2g of low-density polyethylene (LDPE) powder and 0.1g of TS-1 catalyst (the catalyst contains 1.7623% by mass, 18.2426% by mass, and 0.0048% by mass of titanium, silicon, and aluminum, respectively, and has a specific surface area of ​​443.6m²) were mixed. 2 / g, the molecular sieve with a pore size of 0.39nm (purchased from Nanjing Xianfeng Nanomaterials Technology Co., Ltd., model XFF08) and 15mL of water were added to a quartz tube reactor to obtain a dispersion;

[0134] (2) Transfer the quartz tube reactor to a high-pressure reactor, fill it with high-purity air at a pressure of 1.5 MPa, stir at 300 rpm, set a temperature gradient to carry out the catalytic cracking reaction, raise the temperature to 140°C at a set heating rate of 5°C / min and hold it at 1 h; raise the temperature again to 200°C and hold it for 2 h; then lower the temperature to 140°C to carry out the catalytic cracking reaction, and set the reaction time to 9 h, so that the LDPE dispersed in the water is converted into liquid long-chain dicarboxylic acid in three steps;

[0135] (3) After the reaction is completed within the set time, the reactor is allowed to cool to room temperature naturally and then post-processing is performed: the gas generated by the reaction is collected with a gas bag, the reactor is then cleaned with a mixed solution of ethanol and dichloromethane, the filtered solid and liquid are collected, and a brownish-yellow oily liquid is obtained by rotary evaporator. The liquid is detected to be a long-chain dicarboxylic acid.

[0136] Example 15

[0137] (1) Mix 0.2g of a mixed plastic powder (HDPE, LDPE, PP, and LLDPE in a weight ratio of 1:1:1:1), and 0.1g of TS-1 catalyst (in which the contents of titanium, silicon, and aluminum are 1.7623% by mass, 18.2426% by mass, and 0.0048% by mass, respectively, and the specific surface area is 443.6m²). 2 / g, the molecular sieve with a pore size of 0.39nm (purchased from Nanjing Xianfeng Nanomaterials Technology Co., Ltd., model XFF08) and 15mL of water were added to a quartz tube reactor to obtain a dispersion;

[0138] (2) Transfer the quartz tube reactor to a high-pressure reactor, fill it with high-purity air at a pressure of 1.5 MPa, stir at 300 rpm, set a temperature gradient to carry out the catalytic cracking reaction, raise the temperature to 140°C at a set heating rate of 5°C / min and hold it at 1h; raise the temperature again to 200°C and hold it for 2h; then lower the temperature to 140°C to carry out the catalytic cracking reaction, and set the reaction time to 9h, so that the mixed powder dispersed in water is converted into liquid long-chain dicarboxylic acid in three steps;

[0139] (3) After the reaction is completed within the set time, the reactor is allowed to cool to room temperature naturally and then post-processing is performed: the gas generated by the reaction is collected with a gas bag, the reactor is then cleaned with a mixed solution of ethanol and dichloromethane, the filtered solid and liquid are collected, and a brownish-yellow oily liquid is obtained by rotary evaporator. The liquid is detected to be a long-chain dicarboxylic acid.

[0140] Example 16

[0141] (1) Take 0.2g of shredded SF Express packaging bag and 0.1g of TS-1 catalyst (the catalyst contains 1.7623% by mass of titanium, 18.2426% by mass of silicon, and 0.0048% by mass of aluminum, respectively, and has a specific surface area of ​​443.6m²). 2 / g, the molecular sieve with a pore size of 0.39nm (purchased from Nanjing Xianfeng Nanomaterials Technology Co., Ltd., model XFF08) and 15mL of water were added to a quartz tube reactor to obtain a dispersion;

[0142] (2) Transfer the quartz tube reactor to a high-pressure reactor, fill it with high-purity air at a pressure of 1.5 MPa, stir at 300 rpm, set a temperature gradient to carry out the catalytic cracking reaction, raise the temperature to 140°C at a set heating rate of 5°C / min and keep it at a constant temperature for 1 hour; raise the temperature again to 200°C and keep it at 2 hours; then lower the temperature to 140°C to carry out the catalytic cracking reaction, and set the reaction time to 9 hours, so that the SF Express packaging bag dispersed in the water is converted into liquid long-chain dicarboxylic acid in three steps;

[0143] (3) After the reaction is completed within the set time, the reactor is allowed to cool to room temperature naturally and then post-processing is performed: the gas generated by the reaction is collected with a gas bag, the reactor is then cleaned with a mixed solution of ethanol and dichloromethane, the filtered solid and liquid are collected, and a brownish-yellow oily liquid is obtained by rotary evaporator. The liquid is detected to be a long-chain dicarboxylic acid.

[0144] Example 17

[0145] (1) Take 0.2g of shredded white plastic bag and 0.1g of TS-1 catalyst (the catalyst contains 1.7623% by mass of titanium, 18.2426% by mass of silicon, and 0.0048% by mass of aluminum, respectively, and has a specific surface area of ​​443.6m²). 2 / g, the molecular sieve with a pore size of 0.39nm (purchased from Nanjing Xianfeng Nanomaterials Technology Co., Ltd., model XFF08) and 15mL of water were added to a quartz tube reactor to obtain a dispersion;

[0146] (2) Transfer the quartz tube reactor to a high-pressure reactor, fill it with high-purity air at a pressure of 1.5 MPa, stir at 300 rpm, set a temperature gradient to carry out the catalytic cracking reaction, raise the temperature to 140°C at a set heating rate of 5°C / min and keep it at a constant temperature for 1 h; raise the temperature again to 200°C and keep it at 2 h; then lower the temperature to 140°C to carry out the catalytic cracking reaction, and set the reaction time to 9 h, so that the white plastic bag dispersed in the water is converted into liquid long-chain dicarboxylic acid in three steps;

[0147] (3) After the reaction is completed within the set time, the reactor is allowed to cool to room temperature naturally and then post-processing is performed: the gas generated by the reaction is collected with a gas bag, the reactor is then cleaned with a mixed solution of ethanol and dichloromethane, the filtered solid and liquid are collected, and a brownish-yellow oily liquid is obtained by rotary evaporator. The liquid is detected to be a long-chain dicarboxylic acid.

[0148] Example 18

[0149] (1) 0.2g of high-density polyethylene (HDPE) plastic powder and 0.05g of TS-1 catalyst (in which the contents of titanium, silicon and aluminum are 1.7623% by mass, 18.2426% by mass and 0.0048% by mass, respectively, and the specific surface area is 443.6m²) were mixed. 2 / g, the molecular sieve with a pore size of 0.39nm (purchased from Nanjing Xianfeng Nanotechnology Co., Ltd., model XFF08) and 15mL of water were added to a quartz tube reactor to obtain a dispersion;

[0150] (2) Transfer the quartz tube reactor to a high-pressure reactor, fill it with high-purity air at a pressure of 1.5 MPa, stir at 300 rpm, set a temperature gradient to carry out catalytic cracking reaction, raise the temperature to 140°C at a set heating rate of 5°C / min and keep it at a constant temperature for 1 h; raise the temperature again to 180°C and keep it at 2 h; then lower the temperature to 140°C to carry out catalytic cracking reaction, and set the reaction time to 9 h, so that the HDPE dispersed in the water is converted into liquid long-chain dicarboxylic acid in three steps;

[0151] (3) After the reaction is completed within the set time, the reactor is allowed to cool to room temperature naturally and then post-processing is performed: the gas generated by the reaction is collected with a gas bag, the reactor is then cleaned with a mixed solution of ethanol and dichloromethane, the filtered solid and liquid are collected, and a brownish-yellow oily liquid is obtained by rotary evaporator. The liquid is detected to be a long-chain dicarboxylic acid.

[0152] Example 19

[0153] (1) 0.15g of high-density polyethylene (HDPE) plastic powder and 0.05g of TS-1 catalyst (in which the contents of titanium, silicon and aluminum are 1.7623% by mass, 18.2426% by mass and 0.0048% by mass, respectively, and the specific surface area is 443.6m²) were mixed. 2 / g, the molecular sieve with a pore size of 0.39nm (purchased from Nanjing Xianfeng Nanotechnology Co., Ltd., model XFF08) and 15mL of water were added to a quartz tube reactor to obtain a dispersion;

[0154] (2) Transfer the quartz tube reactor to a high-pressure reactor, fill it with high-purity air at a pressure of 1.5 MPa, stir at 300 rpm, set a temperature gradient to carry out catalytic cracking reaction, raise the temperature to 140°C at a set heating rate of 5°C / min and keep it at a constant temperature for 1 h; raise the temperature again to 180°C and keep it at 2 h; then lower the temperature to 140°C to carry out catalytic cracking reaction, and set the reaction time to 9 h, so that the HDPE dispersed in the water is converted into liquid long-chain dicarboxylic acid in three steps;

[0155] (3) After the reaction is completed within the set time, the reactor is allowed to cool to room temperature naturally and then post-processing is performed: the gas generated by the reaction is collected with a gas bag, the reactor is then cleaned with a mixed solution of ethanol and dichloromethane, the filtered solid and liquid are collected, and a brownish-yellow oily liquid is obtained by rotary evaporator. The liquid is detected to be a long-chain dicarboxylic acid.

[0156] Example 20

[0157] (1) 0.2g of high-density polyethylene (HDPE) plastic powder and 0.1g of TS-1 catalyst (in which the contents of titanium, silicon and aluminum are 1.7623% by mass, 18.2426% by mass and 0.0048% by mass, respectively, and the specific surface area is 443.6m²) were mixed. 2 / g, the molecular sieve with a pore size of 0.39nm (purchased from Nanjing Xianfeng Nanomaterials Technology Co., Ltd., model XFF08) and 15mL of water were added to a quartz tube reactor to obtain a dispersion;

[0158] (2) Transfer the quartz tube reactor to the high-pressure reactor, fill it with high-purity air at a pressure of 1.5 MPa, stir at 300 rpm, raise the temperature to 140°C at a set heating rate of 5°C / min and heat for 12 hours, so that the HDPE dispersed in the water is converted into liquid long-chain dicarboxylic acid in three steps.

[0159] (3) After the reaction is completed, the reactor is allowed to cool to room temperature naturally and then post-processing is performed: the gas generated by the reaction is collected with a gas bag, the reactor is then cleaned with a mixed solution of ethanol and dichloromethane, the filtered solid and liquid are collected, and a brownish-yellow oily liquid is obtained by rotary evaporator. The liquid is detected to be a long-chain dicarboxylic acid.

[0160] Example 21

[0161] (1) 0.2g of high-density polyethylene (HDPE) plastic powder and 0.1g of TS-1 catalyst (in which the contents of titanium, silicon and aluminum are 1.7623% by mass, 18.2426% by mass and 0.0048% by mass, respectively, and the specific surface area is 443.6m²) were mixed. 2 / g, the molecular sieve with a pore size of 0.39nm (purchased from Nanjing Xianfeng Nanomaterials Technology Co., Ltd., model XFF08) and 15mL of water were added to a quartz tube reactor to obtain a dispersion;

[0162] (2) Transfer the quartz tube reactor to the high-pressure reactor, fill it with high-purity air at a pressure of 1.5MPa, stir at 300rpm, raise the temperature to 200℃ at a set heating rate of 5℃ / min and heat for 12h, so that the HDPE dispersed in the water is converted into liquid long-chain dicarboxylic acid in three steps.

[0163] (3) After the reaction is completed, the reactor is allowed to cool to room temperature naturally and then post-processing is performed: the gas generated by the reaction is collected with a gas bag, the reactor is then cleaned with a mixed solution of ethanol and dichloromethane, the filtered solid and liquid are collected, and a brownish-yellow oily liquid is obtained by rotary evaporator. The liquid is detected to be a long-chain dicarboxylic acid.

[0164] Comparative Example 1

[0165] (1) Add 0.2g of high-density polyethylene (HDPE) powder and 15mL of water to a quartz tube reactor to obtain a dispersion;

[0166] (2) Transfer the quartz tube reactor to a high-pressure reactor, fill it with high-purity air at a pressure of 1.5 MPa, stir at 300 rpm, set a temperature gradient to carry out the catalytic cracking reaction, raise the temperature to 140°C at a set heating rate of 5°C / min and keep it at a constant temperature for 1 h; raise the temperature again to 200°C and keep it at 2 h; then lower the temperature to 140°C to carry out the catalytic cracking reaction, and set the reaction time to 9 h, so that the HDPE dispersed in the water is converted into liquid long-chain dicarboxylic acid in three steps;

[0167] (3) After the reaction is completed within the set time, the reactor is allowed to cool to room temperature naturally and then post-processing is performed: the gas generated by the reaction is collected with a gas bag, the reactor is then cleaned with a mixed solution of ethanol and dichloromethane, the filtered solid and liquid are collected, and a brownish-yellow oily liquid is obtained by rotary evaporator. The liquid is detected to be a long-chain dicarboxylic acid.

[0168] Comparative Example 2

[0169] (1) 0.2g of high-density polyethylene (HDPE) plastic powder and 0.1g of TS-1 catalyst (in which the contents of titanium, silicon and aluminum are 1.7623% by mass, 18.2426% by mass and 0.0048% by mass, respectively, and the specific surface area is 443.6m²) were mixed. 2 / g, the molecular sieve with a pore size of 0.39nm (purchased from Nanjing Xianfeng Nanomaterials Technology Co., Ltd., model XFF08) and 15mL of water were added to a quartz tube reactor to obtain a dispersion;

[0170] (2) Transfer the quartz tube reactor to a high-pressure reactor, fill it with high-purity nitrogen gas at a pressure of 1.5 MPa, stir at 300 rpm, set a temperature gradient to carry out catalytic cracking reaction, raise the temperature to 140°C at a set heating rate of 5°C / min and keep it at a constant temperature for 1 h; raise the temperature again to 200°C and keep it at 2 h; then lower the temperature to 140°C to carry out catalytic cracking reaction, and set the reaction time to 9 h, so that the HDPE dispersed in the water is converted into liquid long-chain dicarboxylic acid in three steps;

[0171] (3) After the reaction time is set, the reactor is allowed to cool to room temperature naturally. Post-processing is then performed. No liquid product is found after 12 hours of reaction, indicating that no degradation reaction occurs under N2 atmosphere.

[0172] Test Example 1

[0173] The XRD patterns of the TS-1 catalyst in Examples 1-21 and Comparative Example 2 are as follows: Figure 2 As shown in the attached diagram, nitrogen adsorption and desorption... Figure 3 As shown.

[0174] Depend on Figure 2 It can be seen that it exhibits a typical MFI structure and does not contain non-framework titanium species. The diffraction peaks are located at 7.9°, 8.9°, 23.2° and 24.1°, corresponding to the

[101] ,

[200] ,

[501] and

[303] crystal planes, respectively, which are characteristic diffraction peaks of molecular sieves with topological structures.

[0175] Depend on Figure 3 As can be seen from the BET test results, TS-1 exhibits a typical microporous structure. For example... Figure 3 As shown, the adsorption capacity of TS-1 molecular sieve increases linearly in the low-pressure range (P / P0 < 0.1), which conforms to a type I isotherm. This is due to the enhanced interaction between N2 and the catalyst within the narrow micropores, leading to micropore filling at very low relative pressures. The specific surface area of ​​TS-1 molecular sieve is 443.6 m². 2 / g, according to the HK calculation method, the pore size of the molecular sieve can be calculated to be 0.39nm.

[0176] Test Example 2

[0177] The brownish-yellow oily liquids obtained in Example 2 and Comparative Example 1 were subjected to infrared spectroscopy (FTIR). See attached FTIR images. Figure 4 The brownish-yellow oily liquid obtained in Example 2 was subjected to NMR analysis, and the NMR spectrum is shown in the figure. Figure 5 The brownish-yellow oily liquid obtained in Example 2 was subjected to mass spectrometry analysis. The high-resolution mass spectrum is shown below. Figure 6 .

[0178] Depend on Figure 4 As can be seen, the FTIR spectrum further confirms the presence of the acid. This vibration can be attributed to the OH stretching of an isolated carboxylic acid, as we observed at 1710 cm⁻¹. -1 The nearby strong peaks are consistent with the characteristic peaks of C=O in carboxylic acids. Furthermore, the stretching vibration of a free OH group in an isolated carboxylic acid is expected to occur at 3550 cm⁻¹. -1 A sharp peak appears nearby.

[0179] Depend on Figure 5 It can be seen from the liquid product 1 The H-NMR spectrum shows a broad peak around 12 ppm, which is an acid peak, and peaks in the 9-10 ppm range, which are aldehyde hydrogen peaks. The 3.5-5.0 ppm region indicates CO, with the hydrogen peak around 4.5 ppm possibly belonging to γ-lactone hydrogen peaks, and the weak signal at 8.1 ppm possibly indicating peroxides (key intermediates in oxidation reactions).

[0180] Depend on Figure 6It can be seen that the main peaks are located at m / z = 117, 131, 145, 159, 173, 187, 201, 215, 229, 243 and 257, respectively, corresponding to C4-C 14 Long-chain dicarboxylic acids within the range.

[0181] Test Example 3

[0182] The catalysts, reaction conditions, types of plastics, and yields of the brownish-yellow oily liquids used in Examples 1-21 and Comparative Examples 1-2 are shown in Table 1. The relationship between the yield of the brownish-yellow oily liquids obtained in Examples 1-3 and the temperature of catalytic cracking reaction II is shown in the graph. Figure 7 As shown.

[0183] The yield of the long-chain dicarboxylic acid liquid product is calculated as (liquid mass / plastic mass) × 100%.

[0184] Table 1

[0185]

[0186]

[0187] As can be seen from the results in Table 1, compared with Comparative Examples 1-2, Examples 1-21 use the method provided by the present invention to catalytically pyrolyze plastics. This method uses titanium silicate molecular sieves as catalysts, which have high catalytic activity and can catalytically pyrolyze the reaction process with water as the reaction medium under mild reaction conditions. It catalytically pyrolyzes polyolefin-containing materials into long-chain dicarboxylic acids, and the yield of long-chain dicarboxylic acids is relatively high. This method provides a new and effective strategy for the economical recycling of polyethylene and meets the industrial recycling needs of high-value-added plastics such as HDPE.

[0188] In Example 20, the reaction was carried out at a constant temperature of 140°C for 12 hours, and the yield of the long-chain dicarboxylic acid liquid product was 56%. In Example 21, the reaction was carried out at a constant temperature of 200°C for 12 hours, and the yield of the long-chain dicarboxylic acid liquid product was 53%. Compared with Examples 20 and 21, Examples 1-19 used a temperature gradient that first increased and then decreased to carry out the catalytic cracking reaction, which not only reduced the reaction time but also reduced the carbon deposition on the catalyst and improved the efficiency of the catalytic cracking reaction.

[0189] In Comparative Example 1, no catalyst was used, and the yield of the long-chain dicarboxylic acid liquid product was only 22%. Examples 1-21, using the method provided by this invention for catalytic cracking of plastics, showed a significant increase in the yield of the long-chain dicarboxylic acid liquid product, indicating that the titanium-silicon molecular sieve catalyst used in this invention has excellent catalytic performance. In Comparative Example 2, the reaction was not carried out under aerobic conditions, but rather under a nitrogen atmosphere, and the plastic did not undergo catalytic cracking.

[0190] The examples demonstrate that TS-1 molecular sieve exhibits good catalytic performance for different types of commercial-grade polyolefin plastics (HDPE, LDPE, and LLDPE) and PP plastics, including SF Express packaging bags and white plastic bags, proving that the catalyst has good versatility.

[0191] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for catalytically pyrolyzing plastics, characterized in that, Includes the following steps: Under aerobic conditions, a mixture of polyolefin-containing materials, titanium-silicon molecular sieve catalyst, and water is subjected to a catalytic cracking reaction.

2. The method according to claim 1, characterized in that, In the titanium-silicon molecular sieve catalyst, the titanium content is 1.7-1.8% by mass, and the silicon content is 18.2-18.5% by mass. Preferably, the specific surface area of ​​the titanium-silicon molecular sieve catalyst is 400-500 m². 2 / g, the pore size of the molecular sieve is 0.3-0.5nm.

3. The method according to claim 1, characterized in that, The catalytic pyrolysis reaction includes: S1. A catalytic cracking reaction I is carried out on the mixture of the polyolefin-containing material, the titanium-silicon molecular sieve catalyst, and the water; S2. The mixture I obtained from the catalytic cracking reaction I is subjected to catalytic cracking reaction II; S3. The mixture II obtained from the catalytic cracking reaction II is subjected to catalytic cracking reaction III.

4. The method according to claim 3, characterized in that, In step S1, the conditions for the catalytic cracking reaction I include at least the following: pressure of 1.5-2.0 MPa, temperature of 140-145 °C, and time of 1-2 h; Preferably, in step S2, the conditions for the catalytic cracking reaction II include at least: a pressure of 1.5-2.0 MPa, a temperature of 180-220°C, and a time of 1-3 h; Preferably, in step S3, the conditions for the catalytic cracking reaction III include at least: a pressure of 1.5-2.0 MPa, a temperature of 140-145 °C, and a time of 5-12 h.

5. The method according to any one of claims 1 to 4, characterized in that, The weight ratio of the titanium-silicon molecular sieve catalyst to the polyolefin-containing material is 0.2-0.6:

1.

6. The method according to any one of claims 1 to 4, characterized in that, The method further includes separating the products of the catalytic cracking reaction to obtain an oily liquid product.

7. The method according to claim 6, characterized in that, The weight ratio of the oily liquid product to the polyolefin-containing material is 0.50-0.94:1; Preferably, the oily liquid product contains C5-C. 20 Aliphatic dicarboxylic acids.

8. The method according to any one of claims 1 to 4, characterized in that, The polyolefin-containing material is selected from polyethylene plastics and / or polypropylene plastics; Preferably, the polyethylene plastic is high-density polyethylene and / or low-density polyethylene.

9. A lysis buffer, characterized in that, The lysis buffer was prepared by the method described in any one of claims 1 to 8; Preferably, the lysis solution contains C5-C 20 Aliphatic dicarboxylic acids.

10. The use of the pyrolysis solution according to claim 9 in the preparation of surfactants.

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