A method for dechlorination and degradation of chlorinated waste plastics into liquid hydrocarbons

Abstract

The application belongs to the technical field of chlorine-containing waste plastic treatment, and specifically discloses a method for dechlorinating and degrading chlorine-containing waste plastics into liquid hydrocarbons; in a certain solvent, the chlorine-containing waste plastics are rapidly dechlorinated under the action of an ionic liquid catalyst; the carbon-hydrogen intermediate after dechlorination is mixed and reacted with a polyolefin or a small-molecule hydrocarbon in a reaction container to be converted into liquid hydrocarbons; the method fully recovers carbon resources in waste plastics, and removes all Cl in the chlorine-containing waste plastics in the form of HCl under the action of the ionic liquid catalyst, thereby realizing co-production of hydrochloric acid; the application does not require hydrogen and precious metal catalysts and other valuable resources, directly converts carbon resources in waste plastics into liquid hydrocarbons without Cl pollution under mild conditions, avoids complicated separation of chlorine-containing mixed products, and provides a feasible path for upgrading and recycling of chlorine-containing waste plastics.

Description

Technical Field

[0001] This invention belongs to the field of chlorine-containing waste plastic treatment technology, and specifically discloses a method for dechlorinating and degrading chlorine-containing waste plastics into liquid hydrocarbons. Background Technology

[0002] As is well known, chlorinated plastics are widely used commercial polymers in packaging, construction, and coatings due to their low price and superior performance. Polyvinyl chloride (PVC), a representative plastic, accounts for 12.7% of global plastic production. However, while chlorinated plastics bring convenience to human life, they also place enormous recycling pressure on the environment. With the increasing severity of white pollution, the resource utilization of waste plastics is receiving more and more attention. Conventional landfill and incineration methods not only pollute land and groundwater resources due to the leaching of organohalides, but also harm the atmospheric environment with the emission of toxic chemicals such as dioxins. Therefore, the recycling rate of chlorinated waste plastics is extremely low. To solve this problem, chemical dechlorination and recycling of chlorinated waste plastics has become a widely researched topic. Existing chemical recycling methods face problems such as catalyst poisoning caused by high chlorine content in polymers and chlorine contamination of products. Improper process design can even lead to equipment contamination and corrosion. Given these existing problems, there is an urgent need to develop a chlorine-resistant conversion system or implement an effective dechlorination step before or during the depolymerization process. Summary of the Invention

[0003] To address the problems in the background art, this invention discloses a method for dechlorinating and degrading chlorine-containing waste plastics into liquid hydrocarbons. The chlorine-containing waste plastics are rapidly dechlorinated and degraded under the action of an ionic liquid catalyst and then mixed with polyolefins or small molecule hydrocarbons to react and transform into liquid hydrocarbons. The degradation rate of chlorine-containing waste plastics can reach 100%, realizing the recovery of carbon resources from waste plastics while simultaneously producing hydrochloric acid.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0005] A method for dechlorinating and degrading chlorinated waste plastics into liquid hydrocarbons includes the following steps: preparing an ionic liquid catalyst by mixing anionic liquid cationic reagent and anionic reagent in a certain proportion; adding a certain amount of chlorinated waste plastics and polyolefins or small molecule hydrocarbons to a container; adding a certain amount of ionic liquid catalyst and solvent to the container in a certain proportion; reacting at a temperature of 25-250℃ for 0.25-48 hours; the chlorinated waste plastics are rapidly dechlorinated and degraded under the action of the ionic liquid catalyst and react with polyolefins or small molecule hydrocarbons to convert into liquid hydrocarbons; after the reaction is completed, chromatographic analysis shows that the liquid hydrocarbon products in the organic phase contain hydrocarbons distributed in the C4-C6 region. 16+ The yields of alkanes, alkenes, and aromatics ranged from 29.3 wt.% to 93.7 wt.% of the total feed.

[0006] Furthermore, in the method for dechlorinating and degrading chlorine-containing waste plastics into liquid hydrocarbons, the chlorine-containing waste plastics are polyvinyl chloride, chlorinated polypropylene, or chlorinated polyvinyl chloride.

[0007] Furthermore, in the method for dechlorinating and degrading chlorine-containing waste plastics into liquid hydrocarbons, the ionic liquid cationic reagent is chlorobutylpyridine, chloro1-butyl-3-methylimidazolium, triethylammonium chloride, trihexyl(tetradecyl)phosphonyl chloride or tetrabutylphosphonium chloride, and the ionic liquid anionic reagent is AlCl3, ZnCl2, FeCl3, CuCl, GaCl3, SnCl2, TiCl4, BCl3, AlF3, AlBr3 or AlI3.

[0008] Furthermore, in the method for dechlorinating and degrading chlorine-containing waste plastics into liquid hydrocarbons, the mass ratio of the ionic liquid cationic reagent to the anionic reagent is 2:1 to 1:2.

[0009] Furthermore, in the method for dechlorinating and degrading chlorine-containing waste plastics into liquid hydrocarbons, the polyolefin is polypropylene, high-density polyethylene, low-density polyethylene, or poly-1-butene.

[0010] Furthermore, in the method for dechlorinating and degrading chlorine-containing waste plastics into liquid hydrocarbons, the small molecule hydrocarbons include, but are not limited to, C4-C4 hydrocarbons. 18 Alkanes or alkenes.

[0011] Furthermore, in the method for dechlorinating and degrading chlorine-containing waste plastics into liquid hydrocarbons, the small molecule hydrocarbons are pentane, isopentane, cyclohexane, octane, 2,4-dimethylpentane, or 1-hexene.

[0012] Furthermore, in the method for dechlorinating and degrading chlorine-containing waste plastics into liquid hydrocarbons, the reaction temperature is 25℃-100℃.

[0013] Furthermore, in the method for dechlorinating and degrading chlorine-containing waste plastics into liquid hydrocarbons, the amount of polyolefins or small molecule hydrocarbons added is 50%-1000% of the mass of the chlorine-containing waste plastics, and the amount of ionic liquid catalyst used is 30-500% of the mass of the substrate being treated, that is, 30-500% of the total amount of the chlorine-containing waste plastics and polyolefins or small molecule hydrocarbons.

[0014] Furthermore, in the method for dechlorinating and degrading chlorine-containing waste plastics into liquid hydrocarbons, the amount of polyolefins or small molecule hydrocarbons added is 100% of the mass of the chlorine-containing waste plastics, and the amount of ionic liquid catalyst used is 250% of the mass of the substrate being treated, that is, 250% of the total amount of the chlorine-containing waste plastics and polyolefins or small molecule hydrocarbons.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] The present invention discloses a method for dechlorinating and degrading chlorine-containing waste plastics into liquid hydrocarbons. Under the action of an ionic liquid catalyst, chlorine-containing waste plastics are rapidly dechlorinated to obtain hydrocarbon intermediates. These hydrocarbon intermediates are then reacted with polyolefins or small molecule hydrocarbons to convert them into liquid hydrocarbons, fully recovering the carbon resources from the waste plastics. The degradation rate of chlorine-containing waste plastics can reach 100%, and the liquid hydrocarbon products contain hydrocarbons distributed in the C4-C6 region. 16+ The invention produces alkanes (including alkanes and cycloalkanes), alkenes (including alkenes and cycloalkenes), and aromatics with a mass yield of 29.3 wt.%-93.7 wt.% of the total feed amount. Furthermore, it removes all the Cl contained in chlorine-containing waste plastics as HCl, with HCl production accounting for 39.4 wt.%-65.8 wt.% of the chlorine-containing waste plastic input, achieving co-production of hydrochloric acid. This invention eliminates the need for expensive resources such as hydrogen and precious metal catalysts, directly converting carbon resources in waste plastics into Cl-free liquid hydrocarbons under mild conditions. This avoids the complex separation of chlorine-containing mixed products and provides a feasible path for the upgrading and recycling of chlorine-containing waste plastics. Detailed Implementation

[0017] To better understand the present invention, the following embodiments further illustrate the content of the invention, but the scope of protection of the present invention is not limited to the following embodiments. Numerous specific details are set forth in the following description to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the present invention can be practiced without one or more of these details.

[0018] Unless otherwise specified, the methods in the following examples are conventional methods, and the sources of the drugs are shown in the table below.

[0019] Drug source

[0020]

[0021]

[0022] Example 1: Dechlorination of PVC plastic catalyzed by ionic liquid catalyst

[0023] The ionic liquid [C4Py]Cl-AlCl3 was prepared by mixing the cationic reagent [C4Py]Cl and the anionic reagent AlCl3 at a mass ratio of 1:2. 0.6 g of PVC was weighed and placed in a pressure-resistant tube equipped with a polytetrafluoroethylene rubber ring. 3 mL of dichloromethane and 1.3 g of [C4Py]Cl-AlCl3 (m[C4Py]Cl:mAlCl3=1∶2) catalyst were added, and the reaction was carried out at 25 °C for 10 h.

[0024] The products were tested using the following method:

[0025] Gas phase products: After the reaction was completed, the upper gaseous products were collected, neutralized, and then analyzed using a Fuli 9700II (equipped with HP-PLOT / Q column 30m×0.32mm×20μm) to analyze the products (C1-C3) in the gas phase.

[0026] Liquid products: After the reaction was complete, the system was cooled and deionized water, chloroform, and the internal standard cis-decahydronaphthalene were added and mixed to separate the phases. The liquid products (C4-C4) in the organic phase were analyzed using a Shimadzu GC-MS 2010 (equipped with an SH-5 capillary column 30m × 0.25mm × 0.25μm). 16+ ).

[0027] HCl content: Dilute the HCl in the aqueous phase and bring the volume to 100 ml. Measure the Cl content using an ion meter equipped with a chloride ion selective electrode.

[0028] Solid products: Cold ethanol is added to the organic phase. After all the solid phase has precipitated, the solid residue is filtered, collected, and dried.

[0029] The results showed that PVC did not produce any gaseous or liquid hydrocarbons in the ionic liquid system. The solid residue accounted for 61.6 wt.%, which was a reddish-brown, sparingly soluble solid, insoluble in PVC solvents tetrahydrofuran and dichloromethane, or commonly used solvents dimethyl sulfoxide and N,N-dimethylformamide. Characterization confirmed that the solid residue was not a PVC raw material. The yield of HCl was 38.3 wt.%, which was basically consistent with the loss of raw material mass.

[0030] The conversion rate is 100% when the reaction substrate is chlorine-containing waste plastic.

[0031] Quantitative calculation of gas phase products, liquid phase products, HCl content, and solid phase products:

[0032]

[0033] Among them, liquid product C i The specific quantitative method is as follows:

[0034]

[0035]

[0036]

[0037] The internal standard was cis-decahydronaphthalene.

[0038] The quantitative method for Cl is as follows:

[0039]

[0040] Example 2: Dechlorination of chlorinated polyvinyl chloride plastic catalyzed by ionic liquid catalyst

[0041] The ionic liquid [Bmim]Cl-FeCl3 was prepared by mixing the cationic reagent [Bmim]Cl and the anionic reagent FeCl3 at a mass ratio of 1:1.5. 0.3 g of chlorinated polyvinyl chloride was weighed and placed in a pressure-resistant tube equipped with a polytetrafluoroethylene gasket. 3 mL of dichloromethane and 1.5 g of [Bmim]Cl-FeCl3 (m[Bmim]Cl:mFeCl3 = 1:1.5) catalyst were added, and the mixture was reacted at 50 °C for 10 h.

[0042] The results showed that chlorinated polyvinyl chloride (PVC) did not produce any gaseous or liquid hydrocarbons in the ionic liquid system. The solid residue accounted for 34.2 wt.%, which was a reddish-brown, sparingly soluble solid in PVC solvents tetrahydrofuran and dichloromethane, or commonly used solvents dimethyl sulfoxide and N,N-dimethylformamide. Characterization confirmed that the solid residue was not a chlorinated PVC raw material. The yield of HCl was 65.8 wt.%, which was basically consistent with the mass loss of the raw material.

[0043] Example 3: Dechlorination of chlorinated polypropylene plastic catalyzed by ionic liquid catalyst

[0044] The ionic liquid Et3NHCl-GaCl3 was prepared by mixing the cationic reagent Et3NHCl and the anionic reagent GaCl3 in a 1:1 mass ratio. 0.3 g of chlorinated polypropylene was weighed and placed in a pressure-resistant tube equipped with a polytetrafluoroethylene (PTFE) gasket. 3 mL of chloroform and 2 g of Et3NHCl-GaCl3 (mEt3NHCl∶mGaCl3=1∶1) catalyst were added, and the mixture was reacted at 70 °C for 10 h.

[0045] The results showed that chlorinated polypropylene did not produce any gaseous or liquid hydrocarbons in the ionic liquid system. The solid residue accounted for 47.9 wt.%, which was a reddish-brown, sparingly soluble solid, insoluble in the chlorinated polypropylene solvents tetrahydrofuran and dichloromethane, or the commonly used solvents dimethyl sulfoxide and N,N-dimethylformamide. Characterization confirmed that the solid residue was not a chlorinated polypropylene feedstock. The yield of HCl was 51.9 wt.%, which was basically consistent with the mass loss of the feedstock.

[0046] Example 4: Co-degradation of PVC plastic and polypropylene (PP) catalyzed by ionic liquid catalyst

[0047] The ionic liquid [C4Py]Cl-AlCl3 was prepared by mixing the cationic reagent [C4Py]Cl and the anionic reagent AlCl3 at a mass ratio of 1:2. 0.3 g of PVC and 0.3 g of PP were weighed and placed in a pressure-resistant tube equipped with a polytetrafluoroethylene (PTFE) gasket. 3 mL of dichloromethane and 1.5 g of [C4Py]Cl-AlCl3 (m[C4Py]Cl:mAlCl3 = 1:2) catalyst were added to each tube, and the mixture was reacted at 25 °C for 2 h.

[0048] The results showed that during the co-conversion of PVC and PP, the majority of the products were liquid products (70.0 wt.%, accounting for 97.4 wt.% of the C and H content in the mixed plastics), and the liquid products contained no Cl, consisting entirely of hydrocarbons. Of these, 49.1 wt.% were alkanes, 49.3 wt.% were alkenes, and 1.6 wt.% were aromatics. Based on the carbon number distribution, the C4-C7 liquid products were primarily branched alkanes, accounting for 48.7% of the total liquid products. C8-C... 16+ The majority of these are olefins (chain olefins and cycloolefins) and aromatics. The yield of HCl is 28.3 wt.%, and PVC is basically completely dechlorinated.

[0049] Example 5: Co-degradation of chlorinated polypropylene plastic and polypropylene (PP) catalyzed by ionic liquid catalyst

[0050] The ionic liquid [Bmim]Cl-FeCl3 was prepared by mixing the cationic reagent [Bmim]Cl and the anionic reagent FeCl3 at a mass ratio of 1:1.5. 0.3 g of chlorinated polypropylene and 0.3 g of polypropylene were weighed and placed in a pressure-resistant tube equipped with a polytetrafluoroethylene (PTFE) gasket. 3 mL of dichloromethane and 1.5 g of [Bmim]Cl-FeCl3 (m[Bmim]Cl:mFeCl3 = 1:1.5) catalyst were added to each, and the mixture was reacted at 50 °C for 10 h.

[0051] The results showed that during the co-conversion of chlorinated polypropylene plastic and polypropylene, the solid residue was minimal (mainly unreacted chlorinated polypropylene adhering to the pipe wall), accounting for 2.8 wt.%. The liquid phase product accounted for 67.2 wt.% and contained no chlorine (Cl), consisting entirely of hydrocarbons. The yield of HCl was 26.0 wt.%, indicating that the chlorinated polypropylene was essentially completely dechlorinated.

[0052] Example 6: Co-degradation of chlorinated polyvinyl chloride plastic and polypropylene (PP) catalyzed by ionic liquid catalyst

[0053] The ionic liquid Et3NHCl-GaCl3 was prepared by mixing the cationic reagent Et3NHCl and the anionic reagent GaCl3 in a 1:1 mass ratio. 0.3 g of chlorinated polyvinyl chloride and 0.3 g of polypropylene were weighed and placed in a pressure-resistant tube equipped with a polytetrafluoroethylene (PTFE) gasket. 3 mL of dichloromethane and 2 g of Et3NHCl-GaCl3 (mEt3NHCl:mGaCl3 = 1:1) catalyst were added respectively, and the mixture was reacted at 70 °C for 10 h.

[0054] The results showed that during the co-conversion of chlorinated polyvinyl chloride (PVC) plastic and polypropylene, the solid residue was minimal (mainly unreacted PVC adhering to the pipe wall), accounting for 4.6 wt.%. The liquid phase product accounted for 62.2 wt.% and contained no chlorine (Cl), consisting entirely of hydrocarbons. The yield of HCl was 32.9 wt.%, indicating that the chlorinated PVC was essentially completely dechlorinated.

[0055] Example 7: Co-degradation of PVC plastic and low-density polyethylene (LDPE) catalyzed by ionic liquid catalysts

[0056] The ionic liquid [C4Py]Cl-AlCl3 was prepared by mixing the cationic reagent [C4Py]Cl and the anionic reagent AlCl3 at a mass ratio of 1:2. 0.3 g of PVC and 1.5 g of LDPE were weighed and placed in a pressure-resistant tube equipped with a polytetrafluoroethylene (PTFE) gasket. 3 mL of dichloromethane and 2 g of [C4Py]Cl-AlCl3 (m[C4Py]Cl:mAlCl3 = 1:2) catalyst were added to each tube, and the mixture was reacted at 70 °C for 2 h.

[0057] The results showed that during the co-conversion of PVC and LDPE, the solid residue was a mixture of white and reddish-brown solids, accounting for 15.6 wt.%, of which the white solids were unreacted LDPE and the reddish-brown solids were products of PVC dechlorination. The liquid phase products accounted for 74.0 wt.% and did not contain chlorine, consisting entirely of hydrocarbons. The yield of HCl was 9.6 wt.%, indicating that PVC was essentially completely dechlorinated.

[0058] Example 8: Co-degradation of PVC and high-density polyethylene (HDPE) catalyzed by ionic liquid catalysts

[0059] The ionic liquid [Bmim]Cl-FeCl3 was prepared by mixing the cationic reagent [Bmim]Cl and the anionic reagent FeCl3 at a mass ratio of 1:1.5. 0.3 g of PVC and 1 g of HDPE were weighed and placed in a reaction vessel, and 3 mL of dichloromethane and 1.5 g of [Bmim]Cl-FeCl3 (m[Bmim]Cl:mFeCl3 = 1:1.5) catalyst were added respectively. The reaction was carried out at 150 °C for 2 h.

[0060] The results showed that during the co-conversion of PVC and HDPE, the solid residue was a mixture of white and reddish-brown solids, accounting for 27.8 wt.%, of which the white solids were unreacted HDPE and the reddish-brown solids were products of PVC dechlorination. The liquid phase products accounted for 56.5 wt.% and contained no C1 elements, consisting entirely of hydrocarbons. The yield of HCl was 13.1 wt.%, indicating that PVC was essentially completely dechlorinated.

[0061] Example 9: Co-degradation of PVC plastic and poly-1-butene catalyzed by ionic liquid catalyst

[0062] The ionic liquid Et3NHCl-GaCl3 was prepared by mixing the cationic reagent Et3NHCl and the anionic reagent GaCl3 in a 1:1 mass ratio. 0.3 g of PVC and 0.3 g of poly-1-butene were weighed and placed in a pressure-resistant tube equipped with a polytetrafluoroethylene (PTFE) gasket. 3 mL of dichloromethane and 1.5 g of Et3NHCl-GaCl3 (mEt3NHCl:mGaCl3 = 1:1) catalyst were added respectively, and the mixture was reacted at 100 °C for 2 h.

[0063] The results showed that during the co-conversion of PVC and poly-1-butene, the solid residue was a mixture of white and reddish-brown solids, accounting for 18.7 wt.%, of which the white solids were unreacted poly-1-butene and the reddish-brown solids were products of PVC dechlorination. The liquid phase product accounted for 50.5 wt.% and did not contain chlorine, consisting entirely of hydrocarbons. The yield of HCl was 29.0 wt.%, indicating that PVC was essentially completely dechlorinated.

[0064] Example 10: Degradation of PVC plastic by ionic liquid catalyst reacting with isopentane

[0065] The ionic liquid [C4Py]Cl-FeCl3 was prepared by mixing the cationic reagent [C4Py]Cl and the anionic reagent FeCl3 at a mass ratio of 1:1.5. 0.3 g of PVC and 0.3 g of isopentane were weighed and placed in a pressure-resistant tube equipped with a polytetrafluoroethylene (PTFE) gasket. 3 mL of dichloromethane and 2 g of [C4Py]Cl-FeCl3 (m[C4Py]Cl:mFeCl3 = 1:1.5) catalyst were added to each tube, and the mixture was reacted at 25 °C for 15 min.

[0066] The results showed that during the co-conversion of PVC and isopentane, the solid residue was minimal (mainly unreacted PVC adhering to the pipe wall), accounting for 2.4 wt.%. The liquid product comprised 68.0 wt.% and contained no chlorine, consisting entirely of hydrocarbons (15.2 wt.% of the liquid product was isopentane). The yield of HCl was 28.4 wt.%, indicating that the PVC was essentially completely dechlorinated.

[0067] Example 11: Degradation of PVC plastic by ionic liquid catalyst reacting with n-pentane

[0068] The ionic liquid Et3NHCl-AlCl3 was prepared by mixing the cationic reagent Et3NHCl and the anionic reagent AlCl3 at a mass ratio of 1:0.5. 0.3 g of PVC and 0.3 g of n-pentane were weighed and placed in a pressure-resistant tube equipped with a polytetrafluoroethylene (PTFE) gasket. 3 mL of dichloromethane and 2 g of Et3NHCl-AlCl3 (mEt3NHCl:mAlCl3 = 1:0.5) catalyst were added respectively, and the mixture was reacted at 25 °C for 15 min.

[0069] The results showed that during the co-conversion of PVC and n-pentane, the solid residue was minimal (mainly unreacted PVC adhering to the pipe wall), accounting for 3.3 wt.%. The liquid product comprised 60.0 wt.% and contained no C1 elements, consisting entirely of hydrocarbons (42.6 wt.% of the liquid product was n-pentane). The yield of HCl was 27.7 wt.%, indicating that the PVC was essentially completely dechlorinated.

[0070] Example 12: Degradation of chlorinated polypropylene plastic by ionic liquid catalyst reacting with n-octane

[0071] The ionic liquid [Bmim]Cl-GaCl3 was prepared by mixing the cationic reagent [Bmim]Cl and the anionic reagent GaCl3 in a 1:1 mass ratio and stirring. 0.3 g of chlorinated polypropylene and 0.15 g of n-octane were weighed and placed in a pressure-resistant tube equipped with a polytetrafluoroethylene rubber ring. 3 mL of chloroform and 2 g of [Bmim]Cl-GaCl3 (m[Bmim]Cl:mGaCl3 = 1:1) catalyst were added respectively, and the mixture was reacted at 50 °C for 10 min.

[0072] The results showed that during the co-conversion of chlorinated polypropylene with n-octane, the solid residue was minimal (mainly unreacted chlorinated polypropylene adhering to the tube wall), accounting for 6.4 wt.%. The liquid product comprised 56.7 wt.% and contained no C1 elements, consisting entirely of hydrocarbons (26.7 wt.% of the liquid product was n-octane). The yield of HCl was 34.3 wt.%, indicating that the chlorinated polypropylene was essentially completely dechlorinated.

[0073] Example 13: Degradation of chlorinated polyvinyl chloride plastic by ionic liquid catalyst reacting with 2,4-dimethylpentane

[0074] The ionic liquid [C4Py]Cl-FeCl3 was prepared by mixing the cationic reagent [C4Py]Cl and the anionic reagent FeCl3 in a 1:1 mass ratio. 0.3 g of chlorinated polyvinyl chloride and 0.15 g of 2,4-dimethylpentane were weighed and placed in a pressure-resistant tube equipped with a polytetrafluoroethylene (PTFE) gasket. 3 mL of chloroform and 2 g of [C4Py]Cl-FeCl3 (m[C4Py]Cl:mFeCl3 = 1:1) catalyst were added, and the mixture was reacted at 50 °C for 10 min.

[0075] The results showed that during the co-conversion of chlorinated polyvinyl chloride (PVC) with 2,4-dimethylpentane, the solid residue was minimal (mainly unreacted PVC adhering to the tube wall), accounting for 1.9 wt.%. The liquid product comprised 54.1 wt.% and contained no chlorine (Cl), consisting entirely of hydrocarbons (15.5 wt.% of the liquid product was 2,4-dimethylpentane). The yield of HCl was 44.0 wt.%, indicating that the PVC was essentially completely dechlorinated.

[0076] Example 14: Degradation of PVC plastic by ionic liquid catalyst reacting with 1-hexene

[0077] The ionic liquid Et3NHCl-AlCl3 was prepared by mixing the cationic reagent Et3NHCl and the anionic reagent AlCl3 at a mass ratio of 1:2. 0.3 g of PVC and 3 g of 1-hexene were weighed and placed in a pressure-resistant tube equipped with a polytetrafluoroethylene (PTFE) gasket. 3 mL of dichloromethane and 1 g of Et3NHCl-AlCl3 (mEt3NHCl:mAlCl3 = 1:2) catalyst were added, and the mixture was reacted at 70 °C for 30 min.

[0078] The results showed that during the co-conversion of PVC and 1-hexene, the solid residue was minimal (mainly unreacted PVC adhering to the pipe wall), accounting for 0.5 wt.%. The liquid product comprised 93.7 wt.% and contained no chlorine, consisting entirely of hydrocarbons (88.4 wt.% of the liquid product was 1-hexene). The yield of HCl was 5.1 wt.%, indicating that the PVC was essentially completely dechlorinated.

[0079] Example 15: Degradation of PVC plastic by ionic liquid catalyst reacting with cyclohexane

[0080] The ionic liquid [Bmim]Cl-GaCl3 was prepared by mixing the cationic reagent [Bmim]Cl and the anionic reagent GaCl3 at a mass ratio of 1:2. 0.3 g of PVC and 0.3 g of cyclohexane were weighed and placed in a pressure-resistant tube equipped with a polytetrafluoroethylene (PTFE) gasket. 3 mL of dichloromethane and 1 g of [Bmim]Cl-GaCl3 (m[Bmim]Cl:mGaCl3 = 1:2) catalyst were added to each tube, and the mixture was reacted at 100 °C for 120 min.

[0081] The results showed that during the co-conversion of PVC and cyclohexane, the solid residue was minimal (mainly unreacted PVC adhering to the pipe wall), accounting for 5.7 wt.%. The liquid product comprised 64.8 wt.% and contained no chlorine, consisting entirely of hydrocarbons (68.8 wt.% of the liquid product was cyclohexane). The yield of HCl was 27.4 wt.%, indicating that the PVC was essentially completely dechlorinated.

[0082] Example 16: Co-degradation of PVC plastic and polypropylene (PP) catalyzed by ionic liquid catalysts

[0083] The ionic liquid [Bmim]Cl-FeCl3 was prepared by mixing the cationic reagent [Bmim]Cl and the anionic reagent FeCl3 at a mass ratio of 1:2. 0.3 g of PVC and 0.3 g of PP were weighed and placed in a pressure-resistant tube equipped with a polytetrafluoroethylene (PTFE) gasket. 3 mL of dichloromethane and 1.5 g of [Bmim]Cl-FeCl3 (m[Bmim]Cl:mFeCl3 = 1:2) catalyst were added to each tube, and the mixture was reacted at 25 °C for 2 h.

[0084] The results showed that during the co-conversion of PVC and PP, the solid residue was a reddish-brown solid (the product after PVC dechlorination), accounting for 50.1 wt.%, while the liquid product accounted for 29.3 wt.% and contained no chlorine (Cl), consisting entirely of hydrocarbons. The yield of HCl was 20.4 wt.%.

[0085] Example 17: Co-degradation of PVC plastic and polypropylene (PP) catalyzed by ionic liquid catalysts

[0086] The ionic liquid Et3NHCl-GaCl3 was prepared by mixing the cationic reagent Et3NHCl and the anionic reagent GaCl3 at a mass ratio of 1:1.75. 0.3g of PVC and 0.3g of PP were weighed and placed in a pressure-resistant tube equipped with a polytetrafluoroethylene (PTFE) gasket. 3mL of dichloromethane and 1.5g of Et3NHCl-GaCl3 (mEt3NHCl:mGaCl3 = 1:1.75) catalyst were added to each tube, and the mixture was reacted at 50℃ for 2 hours.

[0087] The results showed that during the co-conversion of PVC and PP, the solid residue was a reddish-brown solid (the product after PVC dechlorination), accounting for 23.2 wt.%, while the liquid product accounted for 51.3 wt.% and contained no chlorine (Cl), consisting entirely of hydrocarbons. The yield of HCl was 25.5 wt.%.

[0088] Example 18: Co-degradation of PVC plastic and polypropylene (PP) catalyzed by ionic liquid catalysts

[0089] Cationic reagent [P] 14，6，6，6 Ionic liquids [P] were prepared by mixing Cl and the anionic reagent AlCl3 at a mass ratio of 1:1.5 and stirring. 14，6，6，6 Cl-AlCl3. Weigh 0.3g PVC and 0.3g PP into a reaction vessel, add 3mL dichloromethane and 1.5g [P] respectively. 14，6，6，6 Cl-AlCl3(m[P 14，6，6，6 The catalyst (Cl:mAlCl3 = 1:1.5) was reacted at 250℃ for 2 hours.

[0090] The results showed that during the co-conversion of PVC and PP, the solid residue was a reddish-brown solid (the product after PVC dechlorination), accounting for 6.8 wt.%, while the liquid product accounted for 62.7 wt.% and contained no Cl element, consisting entirely of hydrocarbons. The yield of HCl was 27.4 wt.%.

[0091] Example 19: Co-degradation of PVC plastic and polypropylene (PP) catalyzed by ionic liquid catalysts

[0092] The ionic liquid Bu4PCl-CuCl was prepared by mixing the cationic reagent Bu4PCl and the anionic reagent CuCl in a mass ratio of 1:2. 0.3 g of PVC and 0.3 g of PP were weighed and placed in a reaction vessel, and 3 mL of dichloromethane and 1.5 g of Bu4PCl-CuCl (m[Bu4PCl∶mCuCl=1∶2] catalyst) were added respectively. The reaction was carried out at 150 °C for 2 h.

[0093] The results showed that during the co-conversion of PVC and PP, the solid residue was a reddish-brown solid (the product after PVC dechlorination), accounting for 25.8 wt.%, while the liquid product accounted for 48.9 wt.% and contained no chlorine element, consisting entirely of hydrocarbons. The yield of HCl was 24.8 wt.%.

[0094] Example 20: Co-degradation of PVC plastic and polypropylene (PP) catalyzed by ionic liquid catalysts

[0095] The ionic liquid [Bmim]Cl-SnCl2 was prepared by mixing the cationic reagent [Bmim]Cl and the anionic reagent SnCl2 in a mass ratio of 1:1. 0.3 g of PVC and 0.3 g of PP were weighed and placed in a pressure-resistant tube equipped with a polytetrafluoroethylene (PTFE) gasket. 3 mL of dichloromethane and 1.5 g of [Bmim]Cl-SnCl2 (m[Bmim]Cl:mSnCl2 = 1:1) catalyst were added to each tube, and the mixture was reacted at 70 °C for 2 h.

[0096] The results showed that during the co-conversion of PVC and PP, the solid residue was a reddish-brown solid (the product after PVC dechlorination), accounting for 33.8 wt.%, while the liquid product accounted for 45.4 wt.% and contained no Cl element, consisting entirely of hydrocarbons. The yield of HCl was 19.7 wt.%.

[0097] Example 21: Co-degradation of PVC plastic and polypropylene (PP) catalyzed by ionic liquid catalyst

[0098] The ionic liquid Et3NHCl-TiCl4 was prepared by mixing the cationic reagent Et3NHCl and the anionic reagent TiCl4 at a mass ratio of 1:0.75. 0.3 g of PVC and 0.3 g of PP were weighed and placed in a reaction vessel, and 3 mL of dichloromethane and 1.5 g of Et3NHCl-TiCl4 catalyst (mEt3NHCl:mTiCl4 = 1:0.75) were added respectively. The reaction was carried out at 150 °C for 2 h.

[0099] The results showed that during the co-conversion of PVC and PP, the solid residue was a reddish-brown solid (the product after PVC dechlorination), accounting for 32.7 wt.%, while the liquid product accounted for 42.5 wt.% and contained no chlorine (Cl), consisting entirely of hydrocarbons. The yield of HCl was 21.9 wt.%.

[0100] Example 22: Co-degradation of PVC plastic and polypropylene (PP) catalyzed by ionic liquid catalysts

[0101] Cationic reagent [P] 14，6，6，6 Ionic liquid [P] was prepared by mixing Cl and the anionic reagent BCl3 at a mass ratio of 1:0.5 with stirring. 14，6，6，6 Cl-BCl3. Weigh 0.3g of PVC and 0.3g of PP into a pressure-resistant tube equipped with a PTFE gasket, and add 3mL of dichloromethane and 1.5g of [P] to each tube. 14，6，6，6 ]Cl-BCl3(m[P 14，6，6，6 The catalyst (Cl∶m BCl3=1∶0.5) was reacted at 200℃ for 2h.

[0102] The results showed that during the co-conversion of PVC and PP, the solid residue was a reddish-brown solid (the product after PVC dechlorination), accounting for 36.5 wt.%, while the liquid product accounted for 36.4 wt.% and contained no chlorine element, consisting entirely of hydrocarbons. The yield of HCl was 24.8 wt.%.

[0103] Example 23: Co-degradation of PVC plastic and polypropylene (PP) catalyzed by ionic liquid catalysts

[0104] The ionic liquid [C4Py]Cl-ZnCl2 was prepared by mixing the cationic reagent [C4Py]Cl and the anionic reagent ZnCl2 at a mass ratio of 1:2. 0.3 g of PVC and 0.3 g of PP were weighed and placed in a pressure-resistant tube equipped with a polytetrafluoroethylene (PTFE) gasket. 3 mL of dichloromethane and 1.5 g of [C4Py]Cl-ZnCl2 (m[C4Py]Cl:mZnCl2 = 1:2) catalyst were added to each tube, and the mixture was reacted at 200 °C for 2 h.

[0105] The results showed that during the co-conversion of PVC and PP, the solid residue was a reddish-brown solid (the product after PVC dechlorination), accounting for 19.5 wt.%, while the liquid product accounted for 57.5 wt.% and contained no chlorine (Cl), consisting entirely of hydrocarbons. The yield of HCl was 22.9 wt.%.

[0106] Example 24: Co-degradation of PVC plastic and polypropylene (PP) by ionic liquid catalysis

[0107] The ionic liquid Bu4PCl-AlBr3 was prepared by mixing the cationic reagent Bu4PCl and the anionic reagent AlBr3 at a mass ratio of 1:1.75. 0.3 g of PVC and 0.3 g of PP were weighed and placed in a pressure-resistant tube equipped with a polytetrafluoroethylene (PTFE) gasket. 3 mL of dichloromethane and 1.5 g of Bu4PCl-AlBr3 (mBu4PCl∶mAlBr3=1∶.75) catalyst were added to each tube, and the mixture was reacted at 70 °C for 2 h.

[0108] The results showed that during the co-conversion of PVC and PP, the solid residue was a reddish-brown solid (the product after PVC dechlorination), accounting for 20.7 wt.%, while the liquid product accounted for 44.3 wt.% and contained no Cl element, consisting entirely of hydrocarbons. The yield of HCl was 25.4 wt.%.

[0109] Example 25: Co-degradation of PVC plastic and polypropylene (PP) catalyzed by ionic liquid catalysts

[0110] The ionic liquid [Bmim]Cl-AlF3 was prepared by mixing the cationic reagent [Bmim]Cl and the anionic reagent AlF3 at a mass ratio of 1:1.5. 0.3 g of PVC and 0.3 g of PP were weighed and placed in a pressure-resistant tube equipped with a polytetrafluoroethylene (PTFE) gasket. 3 mL of dichloromethane and 1.5 g of [Bmim]Cl-AlF3 (m[Bmim]Cl:mAlF3 = 1:1.5) catalyst were added to each tube, and the mixture was reacted at 50 °C for 2 h.

[0111] The results showed that during the co-conversion of PVC and PP, the solid residue was a reddish-brown solid (the product after PVC dechlorination), accounting for 8.4 wt.%, while the liquid product accounted for 64.0 wt.% and contained no chlorine (Cl), consisting entirely of hydrocarbons. The yield of HCl was 26.8 wt.%.

[0112] Example 26: Co-degradation of PVC plastic and polypropylene (PP) catalyzed by ionic liquid catalysts

[0113] The ionic liquid Et3NHCl-AlI3 was prepared by mixing the cationic reagent Et3NHCl and the anionic reagent AlI3 at a mass ratio of 1:1.25. 0.3 g of PVC and 0.3 g of PP were weighed and placed in a pressure-resistant tube equipped with a polytetrafluoroethylene (PTFE) gasket. 3 mL of dichloromethane and 1.5 g of Et3NHCl-AlI3 (mEt3NHCl:mAlI3 = 1:1.25) catalyst were added to each tube, and the mixture was reacted at 50 °C for 2 h.

[0114] The results showed that during the co-conversion of PVC and PP, the solid residue was a reddish-brown solid (the product after PVC dechlorination), accounting for 5.4 wt.%, while the liquid product accounted for 66.2 wt.% and contained no Cl element, consisting entirely of hydrocarbons. The yield of HCl was 27.1 wt.%.

[0115] This invention discloses a method for dechlorinating and degrading chlorine-containing waste plastics into liquid hydrocarbons. In a specific solvent, chlorine-containing waste plastics are rapidly dechlorinated under the action of an ionic liquid catalyst and mixed with other polyolefins or small molecule hydrocarbons to convert them into liquid hydrocarbons. This process removes all the Cl from the chlorine-containing waste plastics as HCl under the action of the ionic liquid catalyst. When chlorine-containing waste plastics are treated alone with an ionic liquid catalyst, the dechlorinated intermediates will form a black, insoluble solid (polycyclic aromatic hydrocarbon) due to the low H / C ratio, as shown in Examples 1-3. When chlorine-containing waste plastics are mixed with polyolefins or small molecule hydrocarbons, as shown in Examples 4-26, the hydrocarbon intermediates after dechlorination can be co-treated with the polyolefins or small molecule hydrocarbons to convert them into liquid hydrocarbons, thus avoiding the formation of polycyclic aromatic hydrocarbons to a certain extent and fully recovering the carbon resources in the waste plastics. This invention does not require hydrogen or precious metal catalysts and directly converts the carbon resources in waste plastics into Cl-free liquid hydrocarbons under mild conditions, avoiding the complex separation of chlorine-containing mixed products and providing a feasible path for the upgrading and recycling of chlorine-containing waste plastics.

[0116] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention, as long as they do not depart from the spirit and scope of the technical solutions of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. A method for dechlorinating and degrading chlorine-containing waste plastics into liquid hydrocarbons, characterized in that, The process includes the following steps: An ionic liquid catalyst is prepared by mixing a cationic reagent and anionic reagent in a specific ratio. A certain amount of chlorinated waste plastic and polyolefins or small molecule hydrocarbons are added to a container, along with a specific amount of ionic liquid catalyst and solvent. The reaction is carried out at 25-250℃ for 0.25-48 hours. Under the action of the ionic liquid catalyst, the chlorinated waste plastic is rapidly dechlorinated and degraded, then reacts with the polyolefins or small molecule hydrocarbons to form liquid hydrocarbons. After the reaction is complete, chromatographic analysis shows that the liquid hydrocarbon products in the organic phase contain hydrocarbons distributed in the C4-C6 region. 16 The yields of alkanes, alkenes, and aromatics ranged from 29.3 wt.% to 93.7 wt.% of the total feed, and the small molecule hydrocarbons included C4-C64 hydrocarbons. 18 The alkane or olefin, wherein the polyolefin is polypropylene, high-density polyethylene, low-density polyethylene or poly-1-butene.

2. The method for dechlorinating and degrading chlorine-containing waste plastics into liquid hydrocarbons according to claim 1, characterized in that, The chlorine-containing waste plastics are polyvinyl chloride, chlorinated polypropylene, or chlorinated polyvinyl chloride.

3. The method for dechlorinating and degrading chlorine-containing waste plastics into liquid hydrocarbons according to claim 1 or 2, characterized in that the ionic liquid cationic reagent is chlorobutylpyridine, chloro1-butyl-3-methylimidazolium, triethylammonium chloride, trihexyl(tetradecyl)phosphonyl chloride or tetrabutylphosphonium chloride, and the ionic liquid anionic reagent is AlCl3, ZnCl2, FeCl3, CuCl, GaCl3, SnCl2, TiCl4, BCl3, AlF3, AlBr3 or AlI3.

4. The method for dechlorinating and degrading chlorine-containing waste plastics into liquid hydrocarbons according to claim 3, characterized in that, The mass ratio of cation reagents to anion reagents in ionic liquids is 2:1 to 1:

2.

5. The method for dechlorinating and degrading chlorine-containing waste plastics into liquid hydrocarbons according to claim 3, characterized in that, The small molecule hydrocarbon is isopentane, cyclohexane, octane, 2,4-dimethylpentane, or 1-hexene.

6. The method for dechlorinating and degrading chlorine-containing waste plastics into liquid hydrocarbons according to claim 3, characterized in that, The reaction temperature is 25℃-100℃.

7. The method for dechlorinating and degrading chlorine-containing waste plastics into liquid hydrocarbons according to claim 3, characterized in that, The amount of polyolefin or small molecule hydrocarbon added is 50%-1000% of the mass of the chlorine-containing waste plastic, and the amount of ionic liquid catalyst is 30-500% of the total amount of chlorine-containing waste plastic and polyolefin or small molecule hydrocarbon.

8. The method for dechlorinating and degrading chlorine-containing waste plastics into liquid hydrocarbons according to claim 7, characterized in that, The amount of polyolefin or small molecule hydrocarbon added is 100% of the mass of the chlorine-containing waste plastic, and the amount of ionic liquid catalyst is 250% of the total amount of chlorine-containing waste plastic and polyolefin or small molecule hydrocarbon.

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