Method for the dechlorination of polyvinyl chloride for the targeted production of high-value chlorine-containing chemicals and applications thereof

Abstract

This invention discloses a method for the directional preparation of high-value chlorine-containing chemicals from polyvinyl chloride (PVC) and its applications, belonging to the field of solid waste recycling technology. The method includes the following steps: constructing a reaction system using PVC, aromatic alcohols, and a solvent; placing the reaction system at a temperature of 100–300 °C for ≥0.2 h to obtain chlorine-containing aromatic compounds; the aromatic alcohols include benzyl alcohol, 2-methylbenzyl alcohol, 3-methylbenzyl alcohol, 4-methylbenzyl alcohol, 4-tert-butylbenzyl alcohol, phenethyl alcohol, 4-bromobenzyl alcohol, p-chlorobenzyl alcohol, 4-hydroxymethylbenzonitrile, or 4-hydroxymethylbiphenyl, etc. This invention is economical and green, achieving the upgrade and conversion of PVC into chlorine-containing aromatic compounds in a single step without a catalyst, which is environmentally friendly and effectively utilizes chlorine resources.

Description

Technical Field

[0001] This invention belongs to the field of solid waste recycling technology, specifically relating to a method for the directional preparation of high-value chlorine-containing chemicals from polyvinyl chloride through dechlorination and its application. Background Technology

[0002] Polyvinyl chloride (PVC) is a type of general-purpose plastic with high chlorine content and wide applications, widely used in building pipes, wires and cables, packaging, and daily necessities. With the increasing service life of PVC products, its waste volume continues to grow. Because PVC molecules contain a large number of covalently bonded chlorine elements, its waste treatment process is more complex than that of polyolefin plastics. Existing industrial methods for treating waste PVC mainly include mechanical recycling, landfill, and incineration, but these methods easily pollute the soil and environment and waste chlorine resources. In contrast, chemically upgrading and recycling waste PVC into high-value chlorine-containing chemicals offers greater economic benefits. However, during chemical recycling, chlorine in PVC is usually released in the form of hydrogen chloride or inorganic chloride salts, making effective recovery and utilization difficult. Existing research has attempted to remove and fix chlorine through electrocatalysis, ball milling, and catalytic pyrolysis, but these methods often require high amounts of catalyst or large amounts of energy. Furthermore, some methods suffer from incomplete dechlorination, poor selectivity, or complex systems, limiting the full and effective utilization of chlorine resources in waste PVC.

[0003] Chlorinated organic compounds are widely used as solvents, pharmaceutical and pesticide intermediates, and functional material precursors due to their excellent properties, possessing high industrial and economic value. Benzyl chloride is an important organic synthesis intermediate, belonging to the class of irritating benzyl halides. In the pesticide field, it can be used to directly synthesize organophosphorus fungicides such as isoprothiolane and isoprothiolane, as well as phenylacetonitrile, benzoyl chloride, and m-phenoxybenzaldehyde. Furthermore, benzyl chloride has wide applications in pharmaceuticals, fragrances, dye auxiliaries, and synthetic resins. Currently, various methods exist for synthesizing aromatic chlorinated compounds, but these methods suffer from high energy consumption, difficulty in obtaining catalysts, and high costs. For example, Chinese patent document CN117463393A discloses a method for preparing benzyl chloride compounds. Under the action of a specific catalyst (including zeolite molecular sieves and metal salts and long-chain alkylsilanes supported on the zeolite molecular sieves), aromatic hydrocarbons and their derivatives are subjected to a chloromethylation reaction with a chloromethyl reagent, and the benzyl chloride compounds are obtained after the reaction. Chinese patent document CN117947434A discloses a method for electrochemical synthesis of chlorinated aromatic and heterocyclic compounds using hydrogen chloride as a chlorine source, which requires hydrochloric acid as the chlorine source for the reaction and the role of electrochemistry.

[0004] Various methods for recycling waste PVC have been reported in the prior art, such as Chinese patent documents with publication numbers CN117821132A and CN106146880A. However, there are no reports of using aromatic alcohols to fix chlorine in waste PVC and generate high-value chlorine-containing compounds. As mentioned above, most of the synthesis of aromatic chlorine-containing compounds currently requires the action of a catalyst or electrocatalysis, and there are very few reactions without a catalyst. Summary of the Invention

[0005] In response to the demand for high-value utilization of PVC waste plastics and the problems existing in the synthesis methods of aromatic chlorine-containing compounds, this invention provides a method for the directional preparation of high-value chlorine-containing chemicals from polyvinyl chloride through dechlorination. This reaction does not require additional pressure or a catalyst and has a relatively fast reaction rate, thus realizing the full utilization of chlorine resources in PVC waste plastics.

[0006] The specific technical solution adopted is as follows: A method for the directional preparation of high-value chlorine-containing chemicals from polyvinyl chloride through dechlorination includes the following steps: A reaction system was constructed using polyvinyl chloride, aromatic alcohols, and a solvent. The reaction system was then subjected to a reaction at 100–300 °C for ≥0.2 h to obtain chlorinated aromatic compounds. Aromatic alcohols have a structural formula of at least one of the compounds shown below: ; ; ; The structural formula of a chlorinated aromatic compound is at least one of the compounds shown in the following formula: ; ; ; In aromatic alcohols and chlorinated aromatic compounds, R is selected from C1-C4 alkyl groups, halogens, oxygen-containing functional groups, nitrogen-containing functional groups, or C6-C12 aryl groups; The solvent should be an organic solvent or a mixture of water and an organic solvent.

[0007] The specific reaction equation is shown below: .

[0008] This invention provides a method for the simultaneous high-value synthesis of chlorinated aromatic compounds using waste polyvinyl chloride (PVC) as a chlorine source. This method converts waste PVC into an in-situ chlorinating agent, utilizing the controlled release of active chlorine species from PVC to achieve a one-step, highly efficient chlorination reaction with aromatic alcohols under catalyst-free conditions. This avoids the equipment corrosion and secondary pollution problems caused by high-concentration hydrochloric acid in traditional heat recovery processes, and breaks the dependence of traditional chlorination reactions on precious metal / acidic catalysts. The process features mild reaction conditions and low energy consumption, achieving a closed-loop recycling of chlorine resources, reducing the production cost of chlorine-containing fine chemicals, and enhancing the resource utilization value of waste polymers.

[0009] Furthermore, in aromatic alcohols and chlorinated aromatic compounds, R is selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, fluorine, chlorine, bromine, iodine, methoxy, aldehyde, ketone, amino, nitro, cyano, phenyl, or naphthyl.

[0010] Further preferably, the aromatic alcohols are selected from benzyl alcohol, 2-methylbenzyl alcohol, 3-methylbenzyl alcohol, 4-methylbenzyl alcohol, 4-tert-butylbenzyl alcohol, phenethyl alcohol, 4-bromobenzyl alcohol, p-chlorobenzyl alcohol, 4-hydroxymethylbenzonitrile, or 4-hydroxymethylbiphenyl; the corresponding chlorinated aromatic compounds are benzyl chloride, 2-methylbenzyl chloride, 3-methylbenzyl chloride, 4-methylbenzyl chloride, 4-tert-butylbenzyl chloride, 2-(chloroethyl)benzene, 4-bromochlorobenzyl, 4-chlorochlorobenzyl, 4-cyanobenzyl chloride, or 4-chloromethylbiphenyl. The method of this invention has high applicability and can be used to prepare various types of aromatic chlorinated compounds.

[0011] Optionally, the organic solvent is acetonitrile, N -Methylpyrrolidone or N -Ethylpyrrolidone, further preferably N -Methylpyrrolidone.

[0012] Furthermore, the mass ratio of water to organic solvent in the solvent is 0–0.1:1, preferably 0–0.045:1. The trace amounts of water contained in the organic solvent, or the combination of water and organic solvent, help stabilize the dechlorination of PVC to form HCl, allowing aromatic alcohols to capture chlorine, thus enabling the full and effective conversion of chlorine resources in waste PVC.

[0013] Preferably, the molar ratio of aromatic alcohols to polyvinyl chloride is 0.1–10:1, more preferably 0.5–5:1, and even more preferably 1.5–4:1. Within this optimized range, it helps to improve the yield of chlorinated aromatic compounds and achieves high raw material utilization.

[0014] Preferably, the ratio of solvent to polyvinyl chloride is 0.5–10 mL:1 mmol, more preferably 1–10 mL:1 mmol, and even more preferably 1–4 mL:1 mmol.

[0015] Preferably, the reaction temperature is 140–250°C and the reaction time is 0.5–5 h. More preferably, the reaction temperature is 190–220°C and the reaction time is 0.5–3 h. Within the optimized range, chlorinated aromatic compounds can be prepared efficiently with high yields at relatively low temperatures.

[0016] Specifically, under standard reaction conditions, 0.0625 g PVC (1 mmol), 0.21628 g benzyl alcohol (2 mmol), 0 g water, and... N 2 mL of methylpyrrolidone was reacted at 200 °C for 2 hours to give benzyl chloride, with a yield of 85%.

[0017] The present invention also provides the application of the method for the directional preparation of high-value chlorine-containing chemicals from polyvinyl chloride through dechlorination in the treatment of waste polyvinyl chloride.

[0018] Waste polyvinyl chloride (PVC) specifically refers to PVC waste, including waste PVC pipes, waste PVC films, and waste PVC sheets. The method of this invention is applicable to various forms of waste PVC samples, achieving a yield of up to 99% for chlorinated aromatic compounds, demonstrating excellent efficiency and adaptability.

[0019] Waste polyvinyl chloride (PVC) needs to be pre-crushed into centimeter-sized flakes, granules, or powder before upgrading and conversion to ensure the resource utilization effect of waste PVC and to achieve high-yield production of chlorinated aromatic compounds such as benzyl chloride.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) Compared with other methods for synthesizing chlorinated aromatic compounds such as benzyl chloride, the present invention has simpler steps, lower equipment requirements, and is easier to implement. Existing representative methods for synthesizing benzyl chloride require electrochemical catalysis to achieve a yield of 85%, while the method of the present invention does not require the addition of any catalyst. N Using methylpyrrolidone and trace amounts of water as reaction solvents, high-value conversion of waste PVC can be achieved in just 2 hours at 200°C without applying additional pressure, producing chlorinated aromatic compounds in high yield.

[0021] (2) The present invention conducts the reaction in a specific solvent system. By controlling the water content in the system, the dechlorination process and product formation can be regulated. Compared with existing treatment methods that require traditional catalysts and electrocatalysis, this method has a relatively simple system, helps to reduce the probability of side reactions, and improves the controllability of chlorine-containing product types, and has the potential to be scaled up to industrial production.

[0022] (3) The method of the present invention can realize the conversion of chlorine in waste PVC, not only limited to benzyl chloride, but also can prepare a variety of types of chlorine-containing aromatic compounds. The corresponding chlorine-containing aromatic compounds have a wide range of applications in the fields of medicine, pesticides and fine chemicals, and can be used as important intermediates for the synthesis of a variety of chemicals. Attached Figure Description

[0023] Figure 1 The image shows the 1H NMR spectrum of the reaction product, benzyl chloride.

[0024] Figure 2 The image shows the carbon NMR spectrum of the reaction product, benzyl chloride. Detailed Implementation

[0025] To make the objectives, features, and advantages of this invention more apparent and understandable, a detailed description is provided below through specific embodiments. Many specific details are set forth in the following description to provide a thorough understanding of the invention. However, the invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below. Technical features in various embodiments of the invention can be combined appropriately without mutual conflict.

[0026] Unless otherwise specified, the operating methods in the following examples are generally performed under conventional conditions or as recommended by the manufacturer. Contents not described in detail in this specification are prior art known to those skilled in the art. Unless otherwise specified, the experimental materials used in the examples below can be purchased from conventional biochemical reagent companies.

[0027] The reaction processes in the following examples and comparative examples were all carried out under normal pressure conditions without applying additional pressure.

[0028] Comparative Example 1 80 μL of analytical grade hydrochloric acid (containing 1 mmol of HCl, 36%–38% by mass), 0.21628 g of benzyl alcohol (2 mmol), and N2 mL of NMP (methylpyrrolidone) was added to a PTFE-lined container, which was then placed in a 25 mL flanged reactor and sealed. The sealed reactor was placed on a reactor equipped with an electromagnetic stirrer, thermocouple, and programmed temperature control. Stirring and heating were initiated. The reaction system was heated to 200 °C and reacted at this temperature for 2 h. After the reaction was completed, the mixture was allowed to cool naturally to room temperature to obtain a reaction mixture. 60 μL of the obtained reaction mixture was diluted with 600 μL of deuterated chloroform (CHCl3) and analyzed using nuclear magnetic resonance spectroscopy. The results showed that the yield of benzyl chloride was 52%.

[0029] Example 1 0.0625 g of polyvinyl chloride (PVC) powder (1 mmol, CR purity), 0.21628 g of benzyl alcohol (2 mmol) and N 2 mL of NMP (methylpyrrolidone) was added to a PTFE-lined container, which was then placed in a 25 mL flanged reactor and sealed. The sealed reactor was placed on a reactor equipped with an electromagnetic stirrer, thermocouple, and programmed temperature control. Stirring and heating were initiated. The reaction system was heated to 200 °C and reacted at this temperature for 2 h. After the reaction was completed, the mixture was allowed to cool naturally to room temperature to obtain a reaction mixture. 60 μL of the obtained reaction mixture was diluted with 600 μL of deuterated chloroform (CHCl3) and analyzed using nuclear magnetic resonance spectroscopy. The results showed that the yield of benzyl chloride was 85%, and the yield of dibenzyl ether, a byproduct, was 8%.

[0030] Specifically, benzyl chloride in the product can be separated by column chromatography (eluent: petroleum ether: ethyl acetate, in a ratio from 100:0 to 80:20).

[0031] The proton and carbon NMR spectra of the product benzyl chloride are shown below. Figure 1 and Figure 2 As shown.

[0032] Example 2 0.0625 g of polyvinyl chloride (PVC) powder (1 mmol, CR purity), different masses of benzyl alcohol (0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 4.0 mmol) and N2 mL of NMP (methylpyrrolidone) was added to polytetrafluoroethylene-lined containers, which were then placed in 25 mL flanged reactors and sealed. The sealed reactors were placed on a reactor equipped with an electromagnetic stirrer, thermocouple, and programmed temperature control. Stirring and heating were initiated. The reaction system was heated to 200 °C and reacted at this temperature for 2 h. After the reaction was complete, the mixture was allowed to cool naturally to room temperature to obtain a reaction mixture. 60 μL of each reaction mixture was diluted with 600 μL of deuterated chloroform (CHCl3) and analyzed using nuclear magnetic resonance spectroscopy. The results showed that the yields of benzyl chloride were 44%, 65%, 78%, 85%, 83%, 85%, and 84%, respectively.

[0033] Example 3 0.0625 g of polyvinyl chloride (PVC) powder (1 mmol, CR purity), 0.21628 g of benzyl alcohol (2 mmol) and N 2 mL of NMP (methylpyrrolidone) was added to a PTFE-lined container, which was then placed in a 25 mL flanged reactor and sealed. The sealed reactor was placed on a reactor equipped with an electromagnetic stirrer, thermocouple, and programmed temperature control. Stirring and heating were initiated. The reaction system was heated to different temperatures (160℃, 170℃, 180℃, 190℃, 200℃, 210℃, 220℃) and reacted at these temperatures for 2 h. After the reaction was completed, the mixture was allowed to cool naturally to room temperature to obtain a reaction mixture. 60 μL of each reaction mixture was diluted with 600 μL of deuterated chloroform (CHCl3) and analyzed using nuclear magnetic resonance spectroscopy. The results showed that the yields of benzyl chloride were 26%, 43%, 68%, 79%, 85%, 75%, and 76%, respectively.

[0034] Example 4 0.0625 g of polyvinyl chloride (PVC) powder (1 mmol, CR purity), 0.21628 g of benzyl alcohol (2 mmol), and different solvents (ultra-dry) were used. N -Methylpyrrolidone, water and NA mixed solvent of methylpyrrolidone (0 g: 2 mL, 0.0018 g: 2 mL, 0.0054 g: 2 mL, 0.009 g: 2 mL, 0.018 g: 2 mL, 0.027 g: 2 mL, 0.036 g: 2 mL, 0.045 g: 2 mL) was added to polytetrafluoroethylene-lined containers, which were then placed in 25 mL flanged reactors and sealed. The sealed reactors were placed on a reactor equipped with an electromagnetic stirrer, thermocouple, and programmed temperature control, and stirring and heating were started. The reaction system was heated to 200 °C and reacted at this temperature for 2 h. After the reaction was completed, it was naturally cooled to room temperature to obtain the reaction mixture. 60 μL of the obtained reaction mixture was diluted with 600 μL of deuterated chloroform (CHCl3) and analyzed using nuclear magnetic resonance spectroscopy. The results showed that the yields of the product benzyl chloride were 56%, 85%, 83%, 82.5%, 80%, 78%, 75%, 72%, and 68%, respectively.

[0035] Example 5 0.0625 g of polyvinyl chloride (PVC) powder (1 mmol, CR purity), 0.21628 g of benzyl alcohol (2 mmol) and N 2 mL of NMP (methylpyrrolidone) was added to a PTFE-lined container, which was then placed in a 25 mL flanged reactor and sealed. The sealed reactor was placed on a reactor equipped with an electromagnetic stirrer, thermocouple, and programmed temperature control. Stirring was started and heating was initiated. The reaction system was heated to 200 °C and reacted at this temperature for different times (0.5 h, 1.0 h, 1.5 h, 2.0 h, 2.5 h, 3.0 h). After the reaction was completed, the mixture was allowed to cool naturally to room temperature to obtain a reaction mixture. 60 μL of each reaction mixture was diluted with 600 μL of deuterated chloroform (CHCl3) and analyzed using nuclear magnetic resonance spectroscopy. The results showed that the yields of benzyl chloride were 61%, 70%, 78%, 85%, 83%, and 84%, respectively.

[0036] Example 6 0.0625 g of polyvinyl chloride (PVC) powder (1 mmol, CR purity), 0.21628 g of benzyl alcohol (2 mmol), and different volumes of... N1 mL, 1.5 mL, 2 mL, 2.5 mL, 3 mL, and 4 mL of methylpyrrolidone were added to polytetrafluoroethylene-lined containers, which were then placed in 25 mL flanged reactors and sealed. The sealed reactors were placed on a reactor equipped with an electromagnetic stirrer, thermocouple, and programmed temperature control. Stirring and heating were initiated. The reaction system was heated to 200 °C and reacted at this temperature for 2 h. After the reaction was complete, the mixture was allowed to cool naturally to room temperature to obtain a reaction mixture. 60 μL of each reaction mixture was diluted with 600 μL of deuterated chloroform (CHCl3) and analyzed using nuclear magnetic resonance spectroscopy. The results showed that the yields of benzyl chloride were 76%, 82%, 85%, 84%, 83%, and 82%, respectively.

[0037] Example 7 0.0625 g of polyvinyl chloride (PVC) powder (1 mmol, CR purity), 0.21628 g of benzyl alcohol (2 mmol), and 2 mL of different solvents were used. N 2-Hydroxyethyl-2-pyrrolidone, dimethyl sulfoxide, N , N - Dimethylformamide, acetonitrile, N -Methylpyrrolidone, N Ethylpyrrolidone, acetone, tetrahydrofuran, 1,4-dioxane, toluene, and cyclohexane were added to a polytetrafluoroethylene-lined container, which was then placed into a 25 mL flanged vessel and sealed. The sealed flanged vessel was placed on a reactor equipped with an electromagnetic stirrer, thermocouple, and programmed temperature control device, and stirring and heating were started. The reaction system was heated to 200 °C and reacted at this temperature for 2 h. After the reaction was completed, it was naturally cooled to room temperature to obtain a reaction mixture. 60 μL of each of the obtained reaction mixtures was diluted with 600 μL of deuterated chloroform (CHCl3) and analyzed by nuclear magnetic resonance spectroscopy. The results showed that the yields of benzyl chloride were 0%, 0%, 0%, 53%, 85%, 82%, 7%, 0%, 0%, 0%, and 0%, respectively.

[0038] Example 8 Waste PVC plastic materials (colored transparent sheets, bottle caps, water pipes, insulation boards) were first crushed to the centimeter level. 0.0625 g of the crushed PVC plastic material (1 mmol), 0.21628 g of benzyl alcohol (2 mmol), and... N2 mL of NMP (methylpyrrolidone) was added to polytetrafluoroethylene-lined containers, which were then placed in 25 mL flanged reactors and sealed. The sealed reactors were placed on a reactor equipped with an electromagnetic stirrer, thermocouple, and programmed temperature control. Stirring and heating were initiated. The reaction system was heated to 200 °C and reacted at this temperature for 2 h. After the reaction was complete, the mixture was allowed to cool naturally to room temperature, yielding a reaction mixture. 60 μL of each reaction mixture was diluted with 600 μL of deuterated chloroform (CHCl3) and analyzed using nuclear magnetic resonance spectroscopy. The results showed that the yields of benzyl chloride were 70%, 66%, 51%, and 62%, respectively.

[0039] Example 9 0.0625 g of polyvinyl chloride (PVC) powder (1 mmol, CR purity), different aromatic alcohol compounds (benzyl alcohol, 2-methylbenzyl alcohol, 3-methylbenzyl alcohol, 4-methylbenzyl alcohol, 4-tert-butylbenzyl alcohol, phenethyl alcohol, 4-bromobenzyl alcohol, p-chlorobenzyl alcohol, 4-hydroxymethylbenzonitrile or 4-hydroxymethylbiphenyl) (2 mmol) and N 2 mL of methylpyrrolidone (NMP) was added to polytetrafluoroethylene-lined containers, which were then placed in 25 mL flanged reactors and sealed. The sealed reactors were placed on a reactor equipped with an electromagnetic stirrer, thermocouple, and programmed temperature control. Stirring and heating were initiated. The reaction system was heated to 200 °C and reacted at this temperature for 2 h. After the reaction was complete, the mixture was allowed to cool naturally to room temperature, yielding a reaction mixture. 60 μL of each reaction mixture was diluted with 600 μL of deuterated chloroform (CHCl3) and analyzed using nuclear magnetic resonance spectroscopy. The results showed that the yields of benzyl chloride, 2-methylbenzyl chloride, 3-methylbenzyl chloride, 4-methylbenzyl chloride, 4-tert-butylbenzyl chloride, 2-(chloroethyl)benzene, 4-bromochlorobenzyl, 4-chlorochlorobenzyl, 4-cyanobenzyl chloride, and 4-chloromethylbiphenyl were 85%, 80%, 79%, 77%, 77%, 77%, 73%, 76%, 81%, and 64%, respectively.

[0040] The embodiments described above provide a detailed explanation of the technical solutions of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, additions, or similar substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for the directional preparation of high-value chlorine-containing chemicals from polyvinyl chloride through dechlorination, characterized in that, Includes the following steps: A reaction system was constructed using polyvinyl chloride, aromatic alcohols, and a solvent. The reaction system was then subjected to a reaction at 100–300 °C for ≥0.2 h to obtain chlorinated aromatic compounds. Aromatic alcohols have a structural formula of at least one of the compounds shown below: ； ； ； The structural formula of a chlorinated aromatic compound is at least one of the compounds shown in the following formula: ； ； ； In aromatic alcohols and chlorinated aromatic compounds, R is selected from C1-C4 alkyl groups, halogens, oxygen-containing functional groups, nitrogen-containing functional groups, or C6-C12 aryl groups; The solvent should be an organic solvent or a mixture of water and an organic solvent.

2. The method for the directional preparation of high-value chlorine-containing chemicals from polyvinyl chloride according to claim 1, characterized in that, R is selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, fluorine, chlorine, bromine, iodine, methoxy, aldehyde, ketone, amino, nitro, cyano, phenyl, or naphthyl.

3. The method for the directional preparation of high-value chlorine-containing chemicals from polyvinyl chloride according to claim 1, characterized in that, The organic solvent is acetonitrile, N -Methylpyrrolidone or N -Ethylpyrrolidone.

4. The method for the directional preparation of high-value chlorine-containing chemicals from polyvinyl chloride according to claim 3, characterized in that, In the solvent, the mass ratio of water to organic solvent is 0 to 0.1:

1.

5. The method for the directional preparation of high-value chlorine-containing chemicals from polyvinyl chloride according to claim 1, characterized in that, The molar ratio of aromatic alcohols to polyvinyl chloride is 0.1 to 10:

1.

6. The method for the directional preparation of high-value chlorine-containing chemicals from polyvinyl chloride according to claim 1, characterized in that, The ratio of solvent to polyvinyl chloride is 0.5–10 mL: 1 mmol.

7. The method for the directional preparation of high-value chlorine-containing chemicals from polyvinyl chloride according to claim 1, characterized in that, The reaction temperature is 140–250℃, and the reaction time is 0.5 h–5 h.

8. The application of the method for the directional preparation of high-value chlorine-containing chemicals from polyvinyl chloride according to any one of claims 1-7 in the treatment of waste polyvinyl chloride.

9. The application of the method for the directional preparation of high-value chlorine-containing chemicals from polyvinyl chloride according to claim 8 in the treatment of waste polyvinyl chloride, characterized in that, Waste polyvinyl chloride (PVC) is selected from waste materials and is pre-crushed into centimeter-sized flakes, granules, or powder before processing.

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