Compound, preparation method and application of compound, homopolymer, preparation method of homopolymer and degradation method of homopolymer

Abstract

The invention provides a compound and a preparation method and application thereof, a homopolymer and a preparation method and a degradation method thereof, and belongs to the technical field of high polymer material synthesis. The compound has a structure as shown in a formula (I) or a formula (II): # imgabs 0 # formula (I) and # imgabs 1 # formula (II). The polyester material synthesized by the compound can be used as a plastic substitute, and can be completely degraded after being used, so that the waste of fossil resources is reduced, and the pollution to the environment is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer material synthesis, and in particular, to a compound, a preparation method thereof, an application thereof, a homopolymer thereof, a preparation method thereof, and a degradation method thereof. Background Art

[0002] Due to their unique properties, polymer materials play an important role in daily life. Compared with other traditional materials, plastics have many advantages, such as durability, low density, corrosion resistance, easy processing, low production cost, etc. These advantages make plastics an indispensable part of life and have a relatively wide range of application fields.

[0003] Currently, the plastic components with high production include polymers such as polyolefins. The synthesis of these polymers relies on petroleum-based monomers and consumes a relatively large amount of fossil resources. At the same time, the degradation period of these polymers is long. The degradation of most plastics requires hundreds to thousands of years, and the wide application of plastics has led to the accumulation of waste plastics in the environment, causing relatively serious pollution.

[0004] Therefore, there is an urgent need to provide a method that can reduce the waste of fossil resources and at the same time reduce environmental pollution. Summary of the Invention

[0005] In view of this, in order to at least partially solve at least one of the above-mentioned technical problems, the present invention provides a compound, a preparation method thereof, an application thereof, a homopolymer thereof, a preparation method thereof, and a degradation method thereof.

[0006] According to an embodiment of one aspect of the present invention, a compound is provided, which has a structure shown in formula (I) or formula (II):

[0007] Formula (I), Formula (II).

[0008] According to an embodiment of another aspect of the present invention, a method for preparing the above compound is provided. Among them, the method for preparing the compound shown in formula (I) includes: in a first solvent, subjecting 3,4-epoxy-1-butene and thiosalicylic acid to a ring-opening reaction to obtain a solution containing 2-((1-hydroxybut-3-en-2-yl)thio)benzoic acid; in the first solvent, subjecting 2-((1-hydroxybut-3-en-2-yl)thio)benzoic acid and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride to an esterification reaction under the catalysis of a first catalyst to obtain an esterification product; subjecting the esterification product to a thio reaction with a sulfurizing agent to obtain a compound having the structure shown in formula (I); or, the method for preparing the compound shown in formula (II) includes: in a second solvent, subjecting 3-isochromanone to a thio reaction with a sulfurizing agent to obtain a compound having the structure shown in formula (II).

[0009] In some embodiments, the temperature of the ring-opening reaction is 55-65 °C, and the reaction time is 18-22 h; the temperature of the esterification reaction is 10-30 °C, and the reaction time is 10-12 h. The first catalyst is 4-dimethylaminopyridine; the sulfurizing agent includes at least one of 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide and phosphorus pentasulfide; the conditions for the thio-reaction are: at a temperature of 110-120 °C, react for 6-12 h.

[0010] In some embodiments, the molar ratio of 3,4-epoxy-1-butene to thiosalicylic acid is 1:(1.05-1.1), and the molar ratio of 2-((1-hydroxybut-3-en-2-yl)thio)benzoic acid, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 4-dimethylaminopyridine is 1:(1.4-1.6):0.2.

[0011] According to an embodiment of another aspect of the present invention, there is provided an application of the above compound as a monomer for preparing a homopolymer.

[0012] According to an embodiment of yet another aspect of the present invention, there is provided a homopolymer comprising repeating units represented by formula (III) or formula (IV).

[0013] Formula (III), Formula (IV).

[0014] In some embodiments, the molecular weight of the homopolymer comprising repeating units represented by formula (III) is 10,000-20,000, and the molecular weight distribution is 1.4-1.5; the molecular weight of the homopolymer comprising repeating units represented by formula (IV) is 25,000-30,000, and the molecular weight distribution is 1.4-1.5.

[0015] According to an embodiment of still another aspect of the present invention, there is provided a method for preparing the above homopolymer, comprising: subjecting the compound represented by formula (I) to ring-opening polymerization in a first solvent under the action of an initiator to prepare a homopolymer having repeating units represented by formula (III); subjecting the compound represented by formula (II) to ring-opening polymerization in a first solvent under the action of an initiator to prepare a homopolymer having repeating units represented by formula (IV).

[0016] Formula (I), Formula (II).

[0017] In some embodiments, the initiator includes a cationic initiator. Preferably, the initiator is BF 3 ·Et2 O, (Et 3 O) + B(C 6 F 5 ) 4 – , [Ph 3 C] + [B(C 6 F 5 ) 4 – Any one of; More preferably, the initiator is [Ph 3 C] + [B(C 6 F 5 ) 4 – .

[0018] According to an embodiment of another aspect of the present invention, there is provided a method for degrading the above-mentioned homopolymer, which degrades the homopolymer in an organic solvent under the catalysis of a second catalyst.

[0019] In some embodiments, the second catalyst is 1,5,7-triazabicyclo[4.4.0]dec-5-ene.

[0020] In some embodiments, the degradation rate of the homopolymer is 98-100%.

[0021] According to the embodiment of the present invention, a rigid benzene ring and a thiocarbonyl lactone polycycle are introduced onto the compound shown in formula (I) or formula (II). The benzene ring can increase the mechanical properties of the subsequent formed homopolymer. The ring tension of the thiocarbonyl lactone polycycle is moderate, and it is relatively easy to open the ring and undergo a polymerization reaction, which is beneficial to the subsequent preparation of polyester compounds, thereby serving as a common plastic substitute and reducing the waste of fossil resources. And it can be degraded by changing the reaction conditions subsequently, thereby reducing the environmental pollution caused by residual waste plastic products. In addition, by introducing a vinyl group on the side chain of the compound shown in formula (I), it helps to further adjust the mechanical properties and thermodynamic properties of the polyester compound through group modification after the subsequent formation of the homopolymer, which is beneficial to further broadening the application fields of polyester compounds. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Through the following description of the embodiments of the present invention with reference to the drawings, the above and other objects, features and advantages of the present invention will become clearer. In the drawings:

[0023] Figure 1 Shows the nuclear magnetic resonance hydrogen spectrum of compound M1 in Example 1 of the present invention;

[0024] Figure 2 ​​The 1H NMR spectrum of the homopolymer PM1 of Example 1 of the present invention is shown;

[0025] Figure 3 The gel permeation chromatogram of the homopolymer PM1 of Example 1 of the present invention is shown;

[0026] Figure 4 The 1H NMR spectrum of the depolymerization product DP1 of Example 1 of the present invention is shown;

[0027] Figure 5 The 1H NMR spectrum of the compound M2 of Example 2 of the present invention is shown;

[0028] Figure 6 The 1H NMR spectrum of the homopolymer PM2 of Example 2 of the present invention is shown;

[0029] Figure 7 The gel permeation chromatogram of the homopolymer PM2 of Example 2 of the present invention is shown;

[0030] Figure 8 The 1H NMR spectrum of the depolymerization product DP2 of Example 2 of the present invention is shown. Detailed Description of the Invention

[0031] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In the following detailed description, for the sake of explanation, many specific details are set forth to provide a thorough understanding of the embodiments of the present invention. However, obviously, one or more embodiments can be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily obscuring the concepts of the present invention.

[0032] The terms used herein are merely for describing specific embodiments and are not intended to limit the present invention. The term "including" used herein indicates the presence of features, steps, operations, but does not exclude the presence or addition of one or more other features.

[0033] In the case of using expressions such as "at least one of A, B, and C, etc.", generally, it should be interpreted according to the meaning that those skilled in the art usually understand this expression (for example, "a system having at least one of A, B, and C" should include but not be limited to a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.). In the case of using expressions such as "at least one of A, B, or C, etc.", generally, it should be interpreted according to the meaning that those skilled in the art usually understand this expression (for example, "a system having at least one of A, B, or C" should include but not be limited to a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.).

[0034] In the present invention, the term "thiocarbonyl lactone" can be understood as a thiocarbonylated lactone, that is, the oxygen on the lactone carbonyl is replaced by sulfur.

[0035] In the present invention, the term "cationic polymerization" can be understood as a polymerization reaction using cations as active centers, and the initiator used is an electrophilic reagent that can accept an electron pair to form a cationic center.

[0036] The components of plastic products commonly used in the related art are mostly polymers such as polyolefins. These polymers are difficult to degrade while having high durability. The degradation of most polymers takes hundreds or even thousands of years. Coupled with the large amount of plastic use, a large amount of waste plastic accumulates in the environment. For the problem of waste plastic accumulation, it is necessary not only to classify and recycle waste plastics, but also to reduce unnecessary plastic use to a certain extent. In addition, the recycling and treatment efficiency of most waste plastics is low, and the performance of the products obtained after recycling and treatment is reduced. To solve the problem of plastic pollution, it is particularly important to achieve the sustainability of plastics.

[0037] In the related art, in order to reduce the dependence on fossil resources and reduce the problem of plastic pollution, attempts have been made to use renewable energy as a production raw material, but it is difficult to solve the subsequent recycling problem. In the related art, attempts have been made to develop biodegradable polymers, which can alleviate the environmental pollution problem caused by the accumulation of waste plastics to a certain extent. However, these polymers usually undergo partial degradation, and the residual polymers still cause relatively serious pollution to the environment.

[0038] In the related art, attempts have been made to use polylactic acid as a substitute for plastics. There is a problem of depolymerization selectivity in the degradation process of polylactic acid. The thermal degradation of polylactic acid produces a mixture of various products. The chemical degradation of polylactic acid catalyzed by tin gives stereoisomers and cyclic oligomers of lactide. Therefore, the recycling and reuse of polylactic acid materials require a large amount of separation and purification processes, which is not conducive to the simplification of the process. For the critical temperature T cLower polymers, i.e., when the polymerization and depolymerization reactions reach equilibrium (ΔGp = 0), the reaction temperature is relatively low. Such polymers are prone to degradation under mild conditions, so they often lack sufficient physical and mechanical properties during use. For example, a completely recyclable polymer synthesized by the chemoselective synthesis of the bioderivative methylene butyrolactone not only requires low-temperature conditions for polymer synthesis, but also the resulting polymer is an amorphous material under normal conditions, and the use performance of the material is poor.

[0039] In the process of implementing the inventive concept, it was found that by designing a specific benzothiocarbonolactone polycyclic compound, the benzene ring therein provides the mechanical properties for subsequent formation of plastics, and the thiocarbonolactone polycyclic ring has appropriate ring strain and is prone to polymerization reaction through ring opening, thereby preparing a polyester compound, which is then applied in the plastic field to reduce the dependence on fossil resources, facilitate subsequent degradation, and reduce the environmental pollution caused by waste plastic products.

[0040] Specifically, according to an embodiment of one aspect of the present invention, a compound is provided, having a structure shown in formula (I) or formula (II):

[0041] Formula (I), Formula (II).

[0042] According to an embodiment of the present invention, the compound shown in formula (I) provides a benzothiocarbonolactone seven-membered ring. Compared with the six-membered ring, the seven-membered ring has greater ring strain and is more prone to ring-opening polymerization reaction to prepare a thio-polyester compound. By introducing the rigid structure of the benzene ring into the main chain, the mechanical properties of the polymer can be enhanced; introducing a vinyl group on the side chain of the benzothiocarbonolactone seven-membered ring can be used for post-polymerization modification, and by modifying specific groups on the polymer side chain, the thermal and mechanical properties of the polymerization can be adjusted, thereby broadening the use functions of the polymer. The compound shown in formula (II) provides a benzene six-membered ring. Similar to formula (I), the benzene ring provides the corresponding mechanical properties to prepare a thio-polyester compound. The compounds of the present invention are relatively prone to ring-opening polymerization to form thio-polyester compounds, which can be used as common plastic substitutes to reduce the dependence on fossil resources. And subsequent degradation can be carried out by changing conditions to reduce the environmental pollution caused by residual waste plastic products.

[0043] According to an embodiment of another aspect of the present invention, a method for preparing the compound as described above is provided. Among them, the method for preparing the compound represented by formula (I) includes: in a first solvent, subjecting 3,4-epoxy-1-butene and thiosalicylic acid to a ring-opening reaction to obtain a solution containing 2-((1-hydroxybut-3-en-2-yl)thio)benzoic acid; in the first solvent, subjecting 2-((1-hydroxybut-3-en-2-yl)thio)benzoic acid and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride to an esterification reaction under the catalysis of a first catalyst to obtain an esterification product; subjecting the esterification product to a thio reaction with a sulfurizing agent to obtain a compound having the structure represented by formula (I).

[0044] It can be understood that the preparation process is as follows:

[0045] 。

[0046] In some embodiments, the first solvent is dichloromethane.

[0047] The method for preparing the compound represented by formula (II) includes: in a second solvent, subjecting 3-isochromanone to a thio reaction with a sulfurizing agent to obtain a compound having the structure represented by formula (II).

[0048] It can be understood that the preparation process is as follows:

[0049] 。

[0050] In some embodiments, the second solvent is toluene.

[0051] In some embodiments, the temperature of the ring-opening reaction is 55 - 65 °C, for example, it can be 55 °C, 60 °C or 65 °C, and preferably 60 °C. The reaction time is 18 - 22 h, for example, it can be 18 h, 20 h or 22 h, and preferably 20 h. The temperature of the esterification reaction is 10 - 30 °C, for example, it can be 10 °C, 15 °C, 20 °C, 25 °C or 30 °C, and the esterification reaction can be carried out at room temperature. The reaction time is 10 - 12 h, for example, it can be 10 h, 11 h or 12 h. With such settings, it helps to promote the reaction and improve the yield of the reaction product. The first catalyst is 4-dimethylaminopyridine, which has strong nucleophilicity and accelerates the esterification reaction. In the preparation of the above two compounds, the sulfurizing agent includes at least one of 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide (Lawesson's reagent) and phosphorus pentasulfide. At high temperatures, P=S in Lawesson's reagent undergoes homolytic cleavage to generate sulfur radicals, which then carry out thiocarbonylation on the carbonyl group of the lactone. The sulfurization mechanism of phosphorus pentasulfide is similar to that of Lawesson's reagent. The conditions for the thio-reaction are: at a temperature of 110 - 120 °C, for example, it can be 115 °C, 116 °C or 117 °C (the temperature should be higher than 110 °C), preferably 115 °C, and react for 6 - 12 h, for example, it can be 6 h, 8 h, 10 h or 12 h, preferably 6 h.

[0052] In some embodiments, the molar ratio of 2-((1-hydroxybut-3-en-2-yl)thio)benzoic acid, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 4-dimethylaminopyridine is 1:(1.4 - 1.6):0.2, for example, it can be 1:1.4:0.2, 1:1.5:0.2 or 1:1.6:0.2, and preferably 1:1.5:0.2. With such settings, it helps to promote and accelerate the smooth progress of the esterification reaction and improve the yield of the esterification product.

[0053] According to an embodiment of another aspect of the present invention, there is provided an application of the above compound as a monomer for preparing a homopolymer.

[0054] According to an embodiment of yet another aspect of the present invention, there is provided a homopolymer comprising repeating units represented by formula (III) or formula (IV).

[0055] Formula (III), Formula (IV).

[0056] According to an embodiment of the present invention, the above-mentioned homopolymer has a thioester group, making this homopolymer have properties similar to plastics, good application performance, and contributing to reducing the dependence on fossil resources. It should be noted that post-polymerization modification can be carried out through alkenyl groups, and groups with specific functions can be modified on the side chains of the homopolymer as needed, thereby broadening the use functions of the homopolymer.

[0057] In some embodiments, the molecular weight of the homopolymer containing the repeating unit shown in formula (III) is 10,000 - 20,000, for example, it can be 10,000, 15,000 or 20,000, and the molecular weight distribution is 1.4 - 1.5, for example, it can be 1.4, 1.45 or 1.5; the molecular weight of the homopolymer containing the repeating unit shown in formula (IV) is 25,000 - 30,000, for example, it can be 25,000, 28,000 or 30,000, and the molecular weight distribution is 1.4 - 1.5, for example, it can be 1.4, 1.45 or 1.5.

[0058] According to an embodiment of the present invention, the above-mentioned molecular weight and the narrow molecular weight distribution indicate good controllability of the polymerization.

[0059] According to an embodiment of another aspect of the present invention, a method for preparing the above-mentioned homopolymer is provided, including: subjecting the compound shown in formula (I) to ring-opening polymerization in a first solvent under the action of an initiator to prepare a homopolymer having the repeating unit shown in formula (III); subjecting the compound shown in formula (II) to ring-opening polymerization in a first solvent under the action of an initiator to prepare a homopolymer having the repeating unit shown in formula (IV);

[0060] Formula (I), Formula (II).

[0061] The reaction process for preparing a homopolymer having the repeating unit shown in formula (III) from the compound shown in formula (I) is as follows:

[0062] , where the value range of n is 100 - 500, for example, it can be 100, 200, 300, 400 or 500.

[0063] The reaction process for preparing a homopolymer having the repeating unit shown in formula (IV) from the compound shown in formula (II) is as follows:

[0064] , where the value range of m is 100 - 500, for example, it can be 100, 200, 300, 400 or 500.

[0065] According to an embodiment of the present invention, through the initiation of the polymerization reaction by an initiator, two compounds are respectively caused to form homopolymers. The obtained homopolymers have thioester groups, and due to their similarity to polyester groups, they can be applied in the plastic field, which is beneficial to the subsequent preparation of environmentally friendly materials.

[0066] In some embodiments, the initiator includes a cationic initiator. The initiator decomposes to generate a cationic active center, and the active center attacks the ester bond of the thiolactone monomer, causing the monomer to ring-open and undergo homopolymerization. Preferably, the initiator is BF 3 ·Et 2 O, (Et 3 O) + B(C 6 F 5 ) 4 – 、[Ph 3 C] + [B(C 6 F 5 ) 4 – any one of them, and further preferably [Ph 3 C] + [B(C 6 F 5 ) 4 – .

[0067] It should be noted that [Ph 3 C] + [B(C 6 F 5 ) 4 – is a cationic initiator, which can react with the nucleophilic site in the compound as an active center to initiate chain polymerization, contributing to the preparation of homopolymers. When using [Ph 3 C] + [B(C 6 F 5 ) 4 – , the polymerization reaction needs to be carried out in a glove box because cationic polymerization is easily interfered by oxygen and water. As mentioned above, the first solvent is dichloromethane.

[0068] Preferably, during the polymerization reaction, the concentration of the compound is 2 mol / L.

[0069] According to an embodiment of another aspect of the present invention, a method for degrading the above-mentioned homopolymer is provided, which causes the homopolymer to degrade in an organic solvent under the catalysis of a second catalyst.

[0070] ​​​​According to an embodiment of the present invention, by adding a second catalyst, the thioester bond in the homopolymer is activated, and then the homopolymer degrades.

[0071] In some embodiments, the second catalyst is 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD).

[0072] According to an embodiment of the present invention, TBD has strong basicity, can activate the thioester bond in the homopolymer, reduce the energy required for its cleavage, and thus promote the degradation.

[0073] Preferably, the molar percentage of TBD added is 5% of the homopolymer.

[0074] The degradation process of the homopolymer having the repeating unit shown in formula (III) is as follows:

[0075] 。

[0076] The degradation process of the homopolymer having the repeating unit shown in formula (IV) is as follows:

[0077] 。

[0078] In some embodiments, the degradation temperature of the homopolymer having the repeating unit shown in formula (III) is 90 - 100 °C, for example, it can be 90 °C, 100 °C, preferably 100 °C, and the time is 1 h.

[0079] In some embodiments, the degradation temperature of the homopolymer having the repeating unit shown in formula (IV) is at room temperature, and the time is 1 h.

[0080] It should be noted that in the degradation method of the homopolymer, whether heating is required is determined by the stability of the thioester bond in the main chain of the homopolymer.

[0081] In some embodiments, the degradation rate of the homopolymer is 100%. Through the above degradation method, complete degradation of the homopolymer can be achieved, further reducing the pollution to the environment caused by the waste plastics prepared therefrom.

[0082] In some embodiments, the organic solvent is toluene.

[0083] In some embodiments, the homopolymer having the repeating unit shown in formula (III) degrades to obtain the compound shown in formula (V); the homopolymer having the repeating unit shown in formula (IV) degrades to obtain the compound shown in formula (VI);

[0084] Formula (V), Formula (VI).

[0085] It should be noted that the chain growth process of the present invention is based on the mechanism of cationic ring-opening polymerization. The homopolymer prepared can be depolymerized through back-biting reaction or cyclization reaction. The compounds of the present invention are reactive towards electrophilic reagents and can undergo cationic polymerization. In addition, during the process of ring-opening polymerization of the compounds, thio-oxygen isomerization occurs, which causes changes in the polymer backbone. After polymerization, the compounds obtain homopolymers. There are cleavable thioester bonds in the main chain of the homopolymers, which can be completely degraded into another small molecule compound, reducing environmental pollution.

[0086] The present invention will be further illustrated by the following examples, related test experiments and their results. In the following detailed description, for the sake of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present invention. However, it is obvious that one or more embodiments can also be implemented without these specific details. Moreover, without conflict, the details in the following embodiments can be arbitrarily combined into other feasible embodiments.

[0087] It should be noted that the following specific examples are only for illustration, and the protection scope of the present invention is not limited thereto. The chemical drugs and raw materials used in the following examples are all obtained commercially or prepared by recognized treatment methods.

[0088] Example 1:

[0089] Preparation of Compound M1:

[0090] 3,4-Epoxy-1-butene (1.5 g, 21.4 mmol, 1 eq) was added to a solution of thiosalicylic acid (1.5 g, 22.4 mmol, 1.05 eq) in dichloromethane (50 mL). The reaction solution was heated under reflux at 60 °C for 20 h, and the reaction solution gradually changed from a suspension to a pale yellow homogeneous solution.

[0091] Subsequently, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI) (6.15 g, 32 mmol, 1.5 eq), 4-dimethylaminopyridine (DMAP) (0.52 g, 4.3 mmol, 0.2 eq) and 20 mL of dichloromethane were added to the above pale yellow homogeneous solution, and the reaction was carried out overnight at room temperature. Subsequently, most of the solvent in the reaction solution was removed by rotary evaporation, and then purified by silica gel column chromatography using a mixed solvent of ethyl acetate / petroleum ether (EA / PE) as the eluent (EA:PE = 1:3, v:v) to obtain a pale pink liquid product with a yield of 30%.

[0092] The light pink liquid product from the previous step (600 mg, 2.91 mmol, 1 eq) was sulfided with Lawesson's reagent. Lawesson's reagent (707 mg, 1.75 mmol, 0.6 eq) was added to a toluene solution (40 mL) of the light pink liquid product from the previous step. The solution was heated under reflux at 115 °C for 6 h, and the reaction solution gradually turned orange. Subsequently, the reaction solution was cooled to room temperature, and most of the solvent was removed under reduced pressure. Using a mixed solvent of EA / PE as the eluent (EA:PE = 1:8, v:v), the orange-yellow liquid compound M1 was purified by silica gel column chromatography. The reaction equation is shown below, and the yield was 21%. Figure 1 The 1H NMR spectrum of compound M1 of Example 1 of the present invention is shown. As Figure 1 shown, the preparation of compound M1 was verified.

[0093] .

[0094] Preparation of homopolymer PM1:

[0095] 111 mg of compound M1 and 25 μL of a dichloromethane solution (0.2 mol / L) of [Ph 3 C] + [B(C 6 F 5 ) 4 – were added to a 4 mL reaction flask, and the stirring speed was set to 500 r / min. The reaction was carried out at room temperature for 24 h, and the polymerization reaction was carried out in a glove box. After the polymerization reaction was completed, the reaction flask was taken out of the glove box, and 100 μL of a dichloromethane (DCM) solution of methanol (MeOH) (MeOH:DCM = 1:100) was added to quench the reaction. Subsequently, the quenched reaction solution was precipitated into 20 mL of cold methanol, and centrifugation was carried out (5000 rpm, 5 min) to remove the precipitant, and then it was dissolved in 1 mL of DCM. The above precipitation process was repeated three times to ensure the removal of residual catalyst or unreacted compounds. The reaction equation is shown below. The prepared homopolymer PM1 was dried to a constant weight in a vacuum drying oven at 40 °C, Figure 2 The 1H NMR spectrum of homopolymer PM1 of Example 1 of the present invention is shown. As Figure 2 shown, the preparation of homopolymer PM1 was confirmed, and the conversion rate of M1 was 99%. Figure 3 The gel permeation chromatogram of homopolymer PM1 of Example 1 of the present invention is shown. As Figure 3 shown, when the ratio of compound M1 to the initiator was 100:1, the molecular weight M n of the obtained homopolymer PM1 was 12700, and the molecular weight distribution M w / M n was 1.47. ​

[0096] 。

[0097] Depolymerization process of homopolymer PM1:

[0098] The depolymerization reaction of the homopolymer PM1 was carried out in a glove box. 100 mg of the homopolymer PM1 was added to a 4 mL reaction flask, and 1 mL of toluene was added to dissolve it to obtain a toluene solution of the homopolymer PM1. Then, 22 μL of a dichloromethane solution (1 mol / L) of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) was added to the reaction flask, and the mixture was heated to 100 °C and reacted for 1 h with a stirring speed set at 500 r / min. The reaction equation is shown below, and the depolymerization rate is 100%. Figure 4 The 1H NMR spectrum of the depolymerization product DP1 of Example 1 of the present invention is shown, confirming the preparation of the depolymerization product DP1.

[0099] 。

[0100] Example 2:

[0101] Preparation of compound M2:

[0102] 3-Isochromanone (20.0 g, 135 mmol, 1 eq) was sulfided with Lawesson's reagent. Lawesson's reagent (32.8 g, 81 mmol, 0.6 eq) was added to a toluene solution (300 mL) of 3-isochromanone, and the solution was heated under reflux at 115 °C for 6 h. The reaction solution gradually changed from yellow to orange. Subsequently, the reaction solution was cooled to room temperature, and insoluble impurities were removed by filtration. Most of the solvent in the filtrate was removed under reduced pressure, and the orange-yellow liquid compound M2 was purified by silica gel column chromatography using a mixed solvent of EA / PE as the eluent (EA:PE = 1:4, v:v). The reaction equation is shown below, and the yield is 26%. Figure 5 The 1H NMR spectrum of the compound M2 of Example 2 of the present invention is shown, as Figure 5 shown, verifying the preparation of the compound M2.

[0103] 。

[0104] Preparation of homopolymer PM2:

[0105] 80 mg of the compound M2, 24 μL of [Ph 3 C] + [B(C 6 F 5 ) 4 – ​The dichloromethane solution (0.2 mol / L) was added to a 4 mL reaction flask, the stirring speed was set at 500 r / min, and it was stirred at room temperature for 0.5 h. The polymerization reaction was carried out in a glove box. After the polymerization reaction was completed, the reaction flask was taken out of the glove box, and 100 μL of a dichloromethane solution of methanol (MeOH:DCM = 1:100) was added to quench the reaction. Subsequently, the quenched reaction solution was precipitated into 20 mL of cold methanol and centrifuged (5000 rpm, 5 min) to remove the precipitant, and then dissolved in 1 mL of DCM. The above precipitation process was repeated three times to ensure the removal of residual catalysts or unreacted compounds. The reaction equation is shown below. The obtained homopolymer PM2 was dried to a constant weight in a vacuum drying oven at 40 °C. Figure 6 The 1H NMR spectrum of the homopolymer PM2 of Example 2 of the present invention is shown, as Figure 2 shown, confirming the preparation of the homopolymer PM2 with a conversion rate of M2 of 99%. Figure 7 The gel permeation chromatogram of the homopolymer PM2 of Example 2 of the present invention is shown. As Figure 7 shown, when the ratio of compound M2 to the initiator is 100:1, the molecular weight M of the obtained homopolymer PM2 n is 26,100, and the molecular weight distribution M w / M n is 1.43.

[0106] .

[0107] Depolymerization process of the homopolymer PM2 (biologically sourced biodegradable polyester material):

[0108] The depolymerization reaction of the homopolymer PM2 was carried out in a glove box. 100 mg of the homopolymer PM2 was taken and added to a 4 mL reaction flask. 1 mL of toluene was added to dissolve it to obtain a toluene solution of the homopolymer PM2. Then, 5 μL of a dichloromethane solution (1 mol / L) of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) was added to the reaction flask, and the reaction was carried out at room temperature for 10 min. The degradation rate was relatively fast. The reaction equation is shown below, and the depolymerization rate is 100%. Figure 8 The 1H NMR spectrum of the depolymerization product DP2 of Example 2 of the present invention is shown, confirming the preparation of the depolymerization product DP2.

[0109] .

[0110] The specific embodiments described above have further elaborated on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A compound having a structure as shown in formula (I) or formula (II): Formula (I), Formula (II).

2. A method for preparing the compound as claimed in claim 1, wherein: The method for preparing the compound represented by formula (I) comprises: In a first solvent, 3,4-epoxy-1-butene and thiosalicylic acid undergo a ring-opening reaction to obtain a solution containing 2-((1-hydroxybut-3-en-2-yl)thio)benzoic acid; In a first solvent, esterifying 2-((1-hydroxybut-3-en-2-yl)thio)benzoic acid and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride under the catalytic action of a first catalyst to obtain an esterified product; The esterification product is subjected to a thiolation reaction with a sulfiding agent to obtain a compound having a structure represented by formula (I); or, The method for preparing the compound represented by formula (II) comprises: In the second solvent, 3-isochromanone reacts with a sulfiding agent to undergo a thiolation reaction to obtain a compound having a structure represented by formula (II).

3. The method according to claim 2, wherein: The temperature of the ring-opening reaction is 55-65°C, and the reaction time is 18-22h; The temperature of the esterification reaction is 10-30°C, the reaction time is 10-12h, and the first catalyst is 4-dimethylaminopyridine; The vulcanizing agent includes at least one of 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphatane-2,4-disulfide and phosphorus pentasulfide; The conditions of the thiolation reaction are: at a temperature of 110-120° C. and for 6-12 hours.

4. Use of the compound as claimed in claim 1 as a monomer for preparing a homopolymer.

5. A homopolymer comprising a repeating unit represented by formula (III) or formula (IV), Formula (III), Formula (IV).

6. A method for preparing the homopolymer as claimed in claim 5, comprising: The compound represented by formula (I) is subjected to ring-opening polymerization in a first solvent under the action of an initiator to prepare a homopolymer having a repeating unit represented by formula (III); The compound represented by formula (II) is subjected to ring-opening polymerization in a first solvent under the action of an initiator to prepare a homopolymer having a repeating unit represented by formula (IV); Formula (I), Formula (II).

7. The method according to claim 6, wherein: The initiator includes a cationic initiator; preferably, the initiator is BF3·Et2O, (Et3O) + B(C6F5)4 – , [Ph3C] + [B(C6F5)4] – Any one of .

8. A method for degrading the homopolymer as claimed in claim 5, wherein: The homopolymer is degraded in an organic solvent under the catalytic action of a second catalyst.

9. The degradation method according to claim 8, wherein: The second catalyst is 1,5,7-triazabicyclo[4.4.0]dec-5-ene.

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