Monomer-recyclable polyester compound as well as synthesis method, monomer recycling method and application thereof

Abstract

The invention provides poly (delta-L) as well as a synthesis method, a monomer recovery method and application thereof. The poly (delta-L) comprises a repeating unit shown in the following formula I: n is an integer greater than 1. According to the technical scheme, poly (delta-L) is obtained from delta-L through one-step ring opening polymerization for the first time, and the polyester monomer can be recycled. The catalyst adopted in the method is good in catalytic activity, and the rate of Michael addition side reaction of delta-L can be inhibited.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer synthesis, and particularly relates to a polyester compound with recyclable monomers and carbon dioxide as a monomer reaction raw material, a synthesis method thereof, a monomer recovery method and uses thereof. Background Art

[0002] Global warming caused by greenhouse gases has already caused significant damage to the Earth's climate. Over 70% of these greenhouse gases are composed of CO2. Therefore, the recovery, enrichment, and utilization of CO2 have become particularly urgent. Furthermore, the large amount of plastic products, the vast majority of which are single-use plastics, which are non-biodegradable, also contributes to severe pollution.

[0003] If we can combine CO2 utilization with polymer synthesis, it will not only mitigate global warming, but polyesters using CO2 as a monomer reaction raw material also have a high probability of becoming biodegradable / recyclable plastics. However, the vast majority of polymers obtained through currently known CO2-based polymer development pathways are either non-degradable or subject to extremely harsh degradation conditions, making monomer recovery impossible. Therefore, if we want to completely solve the problems caused by plastic pollution, it is imperative to introduce monomer recovery into the full life cycle of CO2-based polymers.

[0004] Existing research has primarily employed two strategies for introducing CO2 into polymers. One involves direct CO2 polymerization as a monomer. However, CO2 is thermodynamically very stable, requiring the use of high-energy secondary monomers such as epoxides, aziridines, and hindered Lewis acids and bases. Furthermore, the reaction conditions are often harsh and the monomers expensive. Another strategy involves first generating monomers from CO2 and other substances, and then polymerizing these monomers to produce CO2-based polymers.

[0005] The telomerization reaction of CO2 with 1,3-butadiene to produce the unsaturated six-membered lactone δ-L (3-ethylidene-6-vinyl-tetrahydro-2H-pyran-2-one) containing lactone and olefin functional groups has attracted widespread attention. Both raw materials are inexpensive and readily available, and the lactone has a high potential for ring-opening to produce polyesters. However, current research on the polymerization of δ-L has not yet achieved ring-opening polymerization itself or the synthesis of biodegradable polyesters. The main reason is that the conjugated olefin structure contained in δ-L makes it a very active Michael addition receptor, which makes it difficult to achieve ring-opening polymerization under the conditions of traditional ring-opening polymerization catalysts.

[0006] Therefore, it is urgent to find a new catalyst that can inhibit the Michael addition side reaction of δ-L to achieve the synthesis of polyester with δ-L as a monomer and the monomer can be recycled. Summary of the Invention

[0007] In view of the shortcomings of the prior art described above, the object of the present invention is to provide a polyester (hereinafter referred to as poly(δ-L)) and its synthesis method, monomer recovery method and use, so as to solve the problem that the prior art has not yet achieved the related work of ring-opening polymerization of δ-L itself or the synthesis of polyester with monomer recovery.

[0008] To achieve the above objectives and other related objectives, the present invention is achieved through the following technical solutions.

[0009] The present invention provides a first aspect of a poly(δ-L) comprising a repeating unit as shown in the following formula I:

[0010]

[0011] n is an integer greater than 1.

[0012] Preferably, the main chain structure of the poly(δ-L) includes one or more of a linear structure and a star structure.

[0013] Preferably, the number average molecular weight of the poly(δ-L) is 304.38 to 10,000 g / mol, such as 722 to 2,140 g / mol, 300 to 2,140 g / mol, 722 to 3,000 g / mol, 722 to 5,000 g / mol, or 722 to 10,000 g / mol.

[0014] Preferably, the molecular weight distribution of the poly(δ-L) is 1.00-2.00, such as 1.23-1.39, 1.00-1.39, and 1.23-2.00.

[0015] Preferably, the reactive monomer of poly(δ-L) is a compound δ-L represented by formula II:

[0016]

[0017] A second aspect of the present invention provides a method for synthesizing poly(δ-L) as described above, comprising the following steps: subjecting the compound δ-L represented by Formula II to a polymerization reaction in the presence of a first catalyst and an initiator to obtain poly(δ-L); the synthetic route of the polymerization reaction is as follows:

[0018] The first catalyst includes one or more of organic bases, urea and its derivatives, thiourea and its derivatives; the initiator includes R(OH) m, wherein the initiator is selected from one or more of C1-C30 alkyl alcohols, C1-C30 alkyl alcohol derivatives, C1-C30 alkenyl alcohols, C1-C30 alkenyl alcohol derivatives, alkynyl alcohols, alkynyl alcohol derivatives, monocyclic aromatic alcohols, monocyclic aromatic alcohol derivatives, polycyclic aromatic alcohols, polycyclic aromatic alcohol derivatives, polyheterocyclic aromatic alcohols, polyheterocyclic aromatic alcohol derivatives, polyvinyl alcohol with a molecular weight of 10,000 g / mol or less, and polyethylene glycol with a molecular weight of 10,000 g / mol or less; and n and m are integers greater than 1.

[0019] Preferably, the initiator comprises one or more of benzyl alcohol, 1,4-butanediol, benzhydrol, polyethylene glycol, terephthalate and 1,3-propylene glycol.

[0020] Preferably, the organic base is selected from one or more of phosphazenes, compounds containing a guanidino group, and compounds containing an amidino group.

[0021] Preferably, the urea and its derivatives are selected from one or more of Formula IV and Formula V.

[0022] Preferably, the thiourea and its derivatives are selected from one or more of the structural formulas shown in Formula VI.

[0023]

[0024] Wherein, R1, R2, R3, R4, R5 and R6 are independently selected from one or more of C1 to C30 alkyl, alkyl derivatives, aromatic groups, aromatic derivatives, hydrogen, alkenyl, alkenyl derivatives, alkynyl and alkynyl derivatives.

[0025] Preferably, the molar ratio of δ-L, the first catalyst, and the initiator is 10-50:0.1-10:0.1-10. For example, the molar ratios may be 40-50:1-5:0.1-1, 30-50:1-2.5:0.1-1, or 30-50:2.5-5:1-3. If the first catalyst and initiator content are too high, Michael addition side reactions cannot be avoided. If the first catalyst and initiator content are too low, the ring-opening polymerization reaction rate is extremely slow.

[0026] Preferably, the first catalyst is a mixture of an organic base and one or more selected from urea and its derivatives, thiourea and its derivatives.

[0027] Preferably, the polymerization reaction also comprises a first reaction medium.

[0028] Preferably, the polymerization reaction temperature is -40°C to 0°C, such as -40°C to -25°C, -25°C to 0°C, or -30°C to -25°C. Under the above temperature conditions, the Michael addition reaction can be completely suppressed.

[0029] Preferably, the reaction time of the polymerization reaction is 12 to 120 hours.

[0030] Preferably, after the polymerization reaction is completed, there is a post-processing step, which includes quenching the reaction, purification and drying.

[0031] Preferably, the organic base is selected from t Bu-P4, t Bu-P2, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1,8-diazabicyclo[5.4.0]undec-7-ene, t One or more of Bu-P1, IMes, diethylamine, dimethylamine, triethylamine, N-methylmorpholine, n-octylamine, tri-n-butylamine, laurylamine, stearylamine, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, sodium or potassium alcoholates of C1 to C5, triethanolamine, choline, N-methylmorpholine, pyridine, dimethylaminopyridine, N,N'-dihydroxyethylethylenediamine, β-hydroxyethylethylenediamine, N-(2-hydroxyethyl)ethylenediamine, N,N,N',N'-tetrahydroxyethylethylenediamine, N-hydroxyethylpropylenediamine, trimethylhydroxyethylpropylenediamine and N,N'-di(2-hydroxyethyl)-1,3-propylenediamine.

[0032] Preferably, the urea and its derivatives are selected from 1,3-bis[3,5-bis(trifluoromethyl)phenyl]urea. Applicants have found that only when the first catalyst contains 1,3-bis[3,5-bis(trifluoromethyl)phenyl]urea can the Michael addition reaction be completely suppressed while poly(δ-L) is generated.

[0033] More preferably, when the first catalyst is a mixture of an organic base, urea and its derivatives, and thiourea and its derivatives, the amount of the organic base is ≤ the amount of one or more of urea and its derivatives, thiourea and its derivatives.

[0034] Preferably, the first reaction medium is one or more of tetrahydrofuran (THF), TBD, benzene, toluene, xylene, dichlorobenzene, mesitylene, dichloromethane, chloroform, 1,2-dichloroethane, tetrahydropyrrole, tetrahydropyran, hexahydropyridine, ethyl acetate, ethyl ether, dimethyl ether, methyl ethyl ether, n-hexane, cyclohexane, cyclopentane, acetonitrile, dioxane, N,N-dimethylformamide and dimethyl sulfoxide.

[0035] Preferably, the quenching is performed using a saturated benzoic acid solution in tetrahydrofuran.

[0036] Preferably, the purification method includes one or both of an anti-solvent method and a centrifugation method.

[0037] More preferably, in the anti-solvent method, the anti-solvent is selected from one or more of MeOH, EtOH and n-hexane.

[0038] More preferably, the centrifugal rotation speed is 8000-130000 rpm.

[0039] A third aspect of the present invention provides a method for recovering the poly(δ-L) monomer as described above, the method comprising: using a second catalyst to degrade the poly(δ-L) to recover the δ-L monomer.

[0040] Preferably, the second catalyst is one or more selected from inorganic salts and metal organic compounds.

[0041] Preferably, the second catalyst includes one or more of La[N(SiMe3)2]3, AgCF3SO3, Cu(CF3SO3)2, Fe(CF3SO3)3, Sc(CF3SO3)3, Y(CF3So3)3, FeCl2, Fe(acac)2, Sn(Oct)2, DBTD and ZnCl2.

[0042] Preferably, the amount of the second catalyst added is 1 to 10% based on the amount of the poly(δ-L) substance.

[0043] Preferably, the degradation reaction temperature is 60°C to 120°C.

[0044] Preferably, the heating time is 8 to 20 hours.

[0045] Preferably, the monomer recovery process can be carried out in the presence of a solvent or in the absence of a solvent.

[0046] When the monomer recovery is carried out in a solvent, the solvent may be selected from one or more of toluene, xylene, dichlorobenzene, mesitylene, dioxane, N,N-dimethylformamide and dimethyl sulfoxide.

[0047] Preferably, the degradation is carried out in an inert gas atmosphere. More preferably, the inert gas comprises nitrogen.

[0048] In a fourth aspect, the present invention provides a use of the poly(δ-L) as described above as a reaction raw material in the preparation of polyurethane, wherein the reaction raw material further comprises isocyanate.

[0049] Preferably, the isocyanate is selected from phenyl isocyanate.

[0050] In a fifth aspect, the present invention provides a polyurethane, which is obtained by reacting the poly(δ-L) and isocyanate described above under the catalysis of a third catalyst.

[0051] Preferably, the third catalyst is selected from organotin compounds.

[0052] Preferably, the organotin compound includes one or more of dibutyltin diacetate, dibutyltin dilaurate and stannous octoate.

[0053] In the prior art, in the reaction system of δ-L ring-opening polymerization, due to the presence of conjugated olefins in δ-L, the Michael addition reaction of δ-L occurs the moment the monomer is added. However, the applicant of the present application found that when an equivalent amount of organic base is mixed with urea and its derivatives or thiourea and its derivatives as a catalyst, the hydrogen on the nitrogen structure of urea and its derivatives, thiourea and its derivatives will stabilize the basic group of the organic base in advance to form a stable intermediate, thereby inhibiting the rate of the Michael addition side reaction. The applicant also found that 1,3-bis[3,5-bis(trifluoromethyl)phenyl]urea can even completely inhibit the side reaction, thereby allowing δ-L to selectively undergo ring-opening polymerization to form poly(δ-L).

[0054] When the total amount of monomers and catalyst concentration in the entire reaction system of δ-L ring-opening polymerization remain unchanged, the Michael addition reaction and the ring-opening polymerization reaction are always in a competitive relationship. Therefore, the strategy of catalyst development often focuses on inhibiting the Michael addition reaction and promoting the ring-opening polymerization. However, the applicants of this application have discovered for the first time that using a mixture of 1,3-bis[3,5-bis(trifluoromethyl)phenyl]urea and an organic base as a catalyst can completely inhibit the Michael addition reaction while achieving the δ-L ring-opening polymerization reaction to produce poly(δ-L).

[0055] The beneficial effects of the present invention are:

[0056] 1) The technical solution of the present invention realizes for the first time that δ-L is polymerized in a one-step ring-opening polymerization to obtain a monomer-recyclable polyester, which is labeled as poly(δ-L).

[0057] 2) The polymerization reaction of the present invention uses δ-L generated by the polymerization of CO2 and 1,3-butadiene as a monomer, which can not only effectively utilize carbon dioxide to reduce the greenhouse effect, but also has low cost and easy access to raw materials.

[0058] 3) The poly(δ-L) prepared by this technical solution can not only realize the recovery of δ-L monomers, thereby reducing environmental pollution, but also retain olefin groups on the side chains of the polyester, making it highly capable of post-modification and modification, and has potential application value in the subsequent preparation of various polymer products.

[0059] 4) The first catalyst used in the synthesis method of the present invention has good catalytic activity and can inhibit the rate of the Michael addition side reaction of δ-L. The synthesis method is simple and low-cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 Shown is the hydrogen nuclear magnetic resonance spectrum of poly(δ-L) prepared in Example 1 of the present invention.

[0061] Figure 2 Shown is the carbon nuclear magnetic resonance spectrum of poly(δ-L) prepared in Example 1 of the present invention.

[0062] Figure 3 Shown is the 1H-1H nuclear magnetic resonance spectrum of poly(δ-L) prepared in Example 1 of the present invention.

[0063] Figure 4 Shown is the 1H-13C nuclear magnetic resonance spectrum of poly(δ-L) prepared in Example 1 of the present invention.

[0064] Figure 5 Shown is the MALDI-TOF mass spectrum of poly(δ-L) prepared in Example 1 of the present invention.

[0065] Figure 6 Shown is a comparison of the H NMR spectra of the poly(δ-L) monomer before and after recovery in Example 7 of the present invention. DETAILED DESCRIPTION

[0066] The following describes the implementation of the present invention through specific embodiments. People skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0067] Before further describing the specific embodiments of the present invention, it should be understood that the scope of the present invention is not limited to the specific embodiments described below. It should also be understood that the terminology used in the examples is intended to describe specific embodiments and is not intended to limit the scope of the present invention. The experimental procedures in the following examples, where specific conditions are not specified, were generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers.

[0068] When the embodiments provide numerical ranges, it should be understood that, unless otherwise specified in the present invention, both endpoints of each numerical range and any numerical value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those generally understood by those skilled in the art. In addition to the specific methods, equipment, and materials used in the embodiments, according to the understanding of the prior art by those skilled in the art and the description of the present invention, any methods, equipment, and materials of the prior art similar or equivalent to the methods, equipment, and materials described in the embodiments of the present invention may also be used to implement the present invention.

[0069] Example 1

[0070] This embodiment provides a specific poly (δ-L) and its synthesis method.

[0071] The catalyst for anionic ring-opening polymerization in this embodiment is: t Bu-P4 and 1,3-bis[3,5-bis(trifluoromethyl)phenyl]urea (U1); initiator: BnOH.

[0072] In [δ-L], [ t The reaction was stirred in 0.2 mL of tetrahydrofuran (THF) solution at -25 ° C. for 72 h (the [δ-L] was 39.4 mol / L), and quenched with 5 mL of saturated benzoic acid solution in tetrahydrofuran to obtain 5.2 mL of the first solution.

[0073] After quenching, 300 mL of MeOH was dropwise added to the first solution, and the mixture was centrifuged at 10,000 rpm for 10 minutes. The resulting precipitate was retained, and the supernatant discarded. The same volume of MeOH was added and centrifuged three times. The resulting solid was then dried in a vacuum oven at 50°C for 12 hours to obtain poly(δ-L). Its molecular weight was 2140 g / mol, and its molecular weight distribution was 1.25. The conversion rate of δ-L was 33%.

[0074] The applicant conducted nuclear magnetic resonance analysis and mass spectrometry analysis on the poly(δ-L) prepared in Example 1 as a sample. The specific steps are as follows:

[0075] Nuclear magnetic resonance analysis: The samples were analyzed using a BRUKER AVANCE III HD500 nuclear magnetic resonance instrument with the receiving gain (rg) set to 1 and the number of scans (ns) set to 8. The sample data were then collected and analyzed to obtain the desired spectra.

[0076] Mass spectrometry analysis: The samples were analyzed using a BRUKER Autoflex Speed ​​mass spectrometer with the collection mass range set to 1000-20000, the acceleration voltage to 20 kV, the extraction voltage to 18.6 kV, the focusing voltage to 6.5 kV, and the extraction delay time to 150 ns. The sample data were then collected and analyzed to obtain MALDI-TOF mass spectra.

[0077] The hydrogen nuclear magnetic resonance spectrum of the polyester poly(δ-L) prepared in this example is shown in Figure 1 , carbon NMR spectrum see Figure 2 , 1H-1H NMR spectrum is shown in Figure 3 , 1H-13C NMR spectrum is shown in Figure 4 , MALDI-TOF mass spectrum is shown in Figure 5 .

[0078] Depend on Figures 1 to 5 It can be seen that there is a group of clear single peaks at the chemical shift of δ6.89ppm, indicating that the hydrogen chemical environment of the (8) position in the product is unified. At the same time, the integral ratio of the single peak at δ5.82ppm is 1.00:1.05, which represents the occurrence of direct ring-opening polymerization. Figure 3 The coupling of hydrogen at position (11) and position (12) (δ5.30ppm & δ1.79ppm) proves the merging of the hydrogen at position (12) and position (14). At the same time, the absence of coupling signal at δ4.75ppm further proves the complete disappearance of the ring structure in poly(δ-L). Figure 4 In the figure, all signals have corresponding carbon and hydrogen spectra. There are no coupled signal peaks in the carbon spectrum (δ166.61ppm, δ132.52ppm). They belong to the carbonyl carbon (6) and the olefin carbon (7) without hydrogen directly connected. Further, we analyzed the chain end and main chain structure of poly(δ-L) by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOFMS). The mass spectrometry signal of the polymer ( Figure 5 ) shows that there is only one signal difference of 152.4 g mol -1 The molecular ion peak (M n =n×152.4+147.2g mol -1 ), which is consistent with the linear poly(δ-L) structure of BnOH as the initiator predicted by our feed. 1 In H NMR ( Figure 1 ), it can be observed that BnO － The characteristic signals of the capped benzene ring and the methylene group are at chemical shifts of δ7.35 ppm and δ5.16 ppm, respectively, proving that poly(δ-L) was synthesized using Example 1.

[0079] Example 2

[0080] This embodiment provides a specific poly (δ-L) and its synthesis method.

[0081] In this embodiment, the catalyst for anionic ring-opening polymerization is: 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) and 1,3-bis[3,5-bis(trifluoromethyl)phenyl]urea (U1) as the catalyst for anionic ring-opening polymerization; the initiator is: BnOH.

[0082] The reaction was stirred in 0.2 mL of tetrahydrofuran (THF) solution at -25 ° C. with a molar ratio of [δ-L], [TBD], [U1] and [BnOH] of 50:1:1.5:1 for 72 h (the [δ-L] was 39.4 mol / L), and quenched with 5 mL of saturated benzoic acid solution in tetrahydrofuran to obtain 5.2 mL of the first solution.

[0083] After quenching, 300 mL of MeOH was dropwise added to the first solution, and the mixture was centrifuged at 10,000 rpm for 10 minutes. The resulting precipitate was retained, and the supernatant discarded. The same volume of MeOH was added and centrifuged three times. The resulting solid was then dried in a vacuum oven at 50°C for 12 hours to obtain poly(δ-L). Its molecular weight was 1227 g / mol, and its molecular weight distribution was 1.39. The conversion rate of δ-L was 21%.

[0084] Example 3

[0085] This embodiment provides a specific poly (δ-L) and its synthesis method.

[0086] The catalyst for anionic ring-opening polymerization in this embodiment is: t Bu-P4 and 1,3-bis[3,5-bis(trifluoromethyl)phenyl]urea (U1) were used as catalysts for the anionic ring-opening polymerization; the initiator was BnOH.

[0087] In [δ-L], [ t The reaction was stirred in 0.2 mL of tetrahydrofuran (THF) solution at -25 ° C. for 72 h (the [δ-L] was 39.4 mol / L), and quenched with 5 mL of saturated benzoic acid solution in tetrahydrofuran to obtain 5.2 mL of the first solution.

[0088] After quenching, 300 mL of MeOH was dropwise added to the first solution, and the mixture was centrifuged at 10,000 rpm for 10 minutes. The resulting precipitate was retained and the supernatant discarded. The same volume of MeOH was added and centrifuged three times. The resulting solid was then dried in a vacuum oven at 50°C for 12 hours to obtain poly(δ-L). Its molecular weight was 1821 g / mol, and its molecular weight distribution was 1.31. The conversion rate of δ-L was 9%.

[0089] Example 4

[0090] This embodiment provides a specific poly (δ-L) and its synthesis method.

[0091] In this embodiment, the catalysts for anionic ring-opening polymerization are: 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 1,3-bis[3,5-bis(trifluoromethyl)phenyl]urea (U1) as catalysts for anionic ring-opening polymerization; the initiator is: BnOH.

[0092] The reaction was stirred in 0.2 mL of tetrahydrofuran (THF) solution at -25 ° C. with a molar ratio of [δ-L], [DBU], [U1] and [BnOH] of 50:1:1.5:1 for 72 h (the [δ-L] was 39.4 mol / L), and quenched with 5 mL of saturated benzoic acid solution in tetrahydrofuran to obtain 5.2 mL of the first solution.

[0093] After quenching, 300 mL of MeOH was dropwise added to the first solution, and the mixture was centrifuged at 10,000 rpm for 10 minutes. The resulting precipitate was retained, and the supernatant discarded. The same volume of MeOH was added and centrifuged three times. The resulting solid was then dried in a vacuum oven at 50°C for 12 hours to obtain poly(δ-L). Its molecular weight was 722 g / mol, and its molecular weight distribution was 1.23. The conversion rate of δ-L was 9%.

[0094] Example 5

[0095] This embodiment provides a specific poly (δ-L) and its synthesis method.

[0096] The catalyst for anionic ring-opening polymerization in this embodiment is: t Bu-P2 and 1,3-bis[3,5-bis(trifluoromethyl)phenyl]urea (U1) were used as catalysts for the anionic ring-opening polymerization; the initiator was BnOH.

[0097] In [δ-L], [ tThe molar ratio of Bu-P2], [U1] and [BnOH] was 50:1:1.5:1, and the reaction was stirred in 0.2 mL of tetrahydrofuran (THF) solution at -25 ° C for 72 h (the [δ-L] was 39.4 mol / L), and quenched with 5 mL of saturated benzoic acid in tetrahydrofuran solution to obtain 5.2 mL of the first solution.

[0098] After quenching, 300 mL of MeOH was dropwise added to the first solution, and the mixture was centrifuged at 10,000 rpm for 10 minutes. The resulting precipitate was retained and the supernatant discarded. The same volume of MeOH was added and centrifuged three times. The resulting solid was then dried in a vacuum oven at 50°C for 12 hours to obtain poly(δ-L). Its molecular weight was 1654 g / mol, and its molecular weight distribution was 1.33. The conversion rate of δ-L was 9%.

[0099] Example 6

[0100] This embodiment provides a specific poly (δ-L) and its synthesis method.

[0101] The catalyst for anionic ring-opening polymerization in this embodiment is: t Bu-P4 and 1,3-bis[3,5-bis(trifluoromethyl)phenyl]urea (U1) were used as catalysts for the anionic ring-opening polymerization; the initiator was 1,4-butanediol (1,4-BDO).

[0102] In [δ-L], [ t The reaction was stirred in 0.2 mL of tetrahydrofuran (THF) solution at -25 ° C. for 72 h (the [δ-L] was 39.4 mol / L), and quenched with 5 mL of saturated benzoic acid solution in tetrahydrofuran to obtain 5.2 mL of the first solution.

[0103] After quenching, 300 mL of MeOH was dropwise added to the first solution, and the mixture was centrifuged at 10,000 rpm for 10 minutes. The resulting precipitate was retained and the supernatant discarded. The same volume of MeOH was added and centrifuged three times. The resulting solid was then dried in a vacuum oven at 50°C for 12 hours to obtain poly(δ-L). Its molecular weight was 1881 g / mol, and its molecular weight distribution was 1.26. The conversion rate of δ-L was 20%.

[0104] Example 7

[0105] This embodiment provides a specific method for recovering poly(δ-L) monomers.

[0106] Under a nitrogen atmosphere, 23.4 μmol (50 mg) of the poly(δ-L) sample prepared in Example 1 and 1.2 μmol of La[N(SiMe3)2]3 were added to 4 mL of toluene, and then heated and stirred in an 80°C heating block for 12 h. The solvent in the system was removed by rotary evaporation to complete the recovery of the poly(δ-L) monomer.

[0107] Take out 10mg of the degraded product and analyze its degradation using 1H nuclear magnetic resonance hydrogen. The results are as follows Figure 6 As shown. Figure 6 It can be seen that the blue figure is the initial monomer, the green is the pure spectrum after polymerization, and the red is the monomer NMR spectrum obtained after monomer recovery. It can be seen that the blue and red peak signals are exactly the same, and there is no characteristic signal of blue in the red, which indicates that the poly (δ-L) prepared in Example 1 of the present application can achieve the recovery of its monomer.

[0108] Application Example 1

[0109] 175.8 mg of poly (δ-L) and 23.39 mg of 4,4'-methylenebis (phenyl isocyanate) prepared in Example 6 were taken, 0.2 mL of THF solvent was added, and after complete dissolution, 1.32 mg of dibutyltin diacetate was added as a catalyst, and the mixture was reacted at -25 ° C for 24 hours. After the reaction, 5 mL of saturated benzoic acid in tetrahydrofuran was added to dilute the reaction system to obtain a mixture solution, and the mixture solution was added dropwise to 300 mL of methanol at 0 ° C, centrifuged at 10000 rpm for 10 minutes, the supernatant was discarded and the solid was retained, repeated 3 times, and finally the bottom solid was retained and vacuum dried at 60 ° C for 12 hours to obtain a polyurethane with δ-L as a repeating unit.

[0110] In summary, the technical solution provided by the present invention achieves, for the first time, the conversion of δ-L to poly(δ-L) through a one-step ring-opening polymerization, and the polyester monomer is recyclable. The synthetic raw materials for the δ-L monomer utilized in this technical solution are CO2 and 1,3-butadiene, which are low-cost and readily available. Furthermore, the first catalyst employed in this method exhibits excellent catalytic activity, capable of suppressing the rate of the Michael addition side reaction in δ-L.

[0111] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A polyester, characterized in that Contains the repeating unit shown in the following formula I: n is an integer greater than 1.

2. The polyester according to claim 1, characterized in that The main chain structure of the polyester includes one or both of a linear structure and a star structure; and / or, the number average molecular weight of the polyester is: 304.38 to 10,000 g / mol; And / or, the molecular weight distribution of the polyester is: 1.00 to 2.00; And / or, the reactive monomer of the polyester is a compound δ-L represented by formula II:

3. A method for synthesizing the polyester according to claim 1 or 2, characterized in that: The method comprises the following steps: a compound δ-L represented by formula II is polymerized in the presence of a first catalyst and an initiator to obtain a polyester; the synthetic route of the polymerization reaction is as follows: The first catalyst includes one or more of an organic base, urea and its derivatives, thiourea and its derivatives; The initiator includes R(OH) m ; Wherein, the initiator is selected from one or more of C1-C30 alkyl alcohols, C1-C30 alkyl alcohol derivatives, C1-C30 alkenyl alcohols, C1-C30 alkenyl alcohol derivatives, alkynyl alcohols, alkynyl alcohol derivatives, monocyclic aromatic alcohols, monocyclic aromatic alcohol derivatives, polycyclic aromatic alcohols, polycyclic aromatic alcohol derivatives, polyheterocyclic aromatic alcohols, polyheterocyclic aromatic alcohol derivatives, polyvinyl alcohol with a molecular weight of 10,000 g / mol or less, and polyethylene glycol with a molecular weight of 10,000 g / mol or less; n and m are integers greater than 1.

4. The synthesis method according to claim 3, characterized in that The initiator includes one or more of benzyl alcohol, 1,4-butanediol, benzhydrol, polyethylene glycol, terephthalate and 1,3-propylene glycol; and / or, the organic base is selected from one or more of phosphazenes, compounds containing a guanidino group, and compounds containing an amidino group; And / or, the urea and its derivatives are selected from one or more of Formula IV and Formula V; And / or, the thiourea and its derivatives have the structural formula shown in Formula VI or more; wherein R1, R2, R3, R4, R5, and R6 are independently selected from one or more of C1-C30 alkyl, alkyl derivatives, aromatic groups, aromatic derivatives, hydrogen, alkenyl, alkenyl derivatives, alkynyl, and alkynyl derivatives; and / or, the molar ratio of the δ-L, the first catalyst and the initiator is 10-50:0.1-10:0.1-10; And / or, the first catalyst is a mixture of an organic base and one or more selected from urea and its derivatives, thiourea and its derivatives; And / or, the polymerization reaction further comprises a first reaction medium; And / or, the reaction temperature of the polymerization reaction is -40°C to 0°C; And / or, after the polymerization reaction is completed, there is a post-processing step, which includes quenching the reaction, purification and drying.

5. The synthesis method according to claim 4, characterized in that The organic base is selected from t Bu-P4, t Bu-P2, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1,8-diazabicyclo[5.4.0]undec-7-ene, t One or more of Bu-P1, IMes, diethylamine, dimethylamine, triethylamine, N-methylmorpholine, n-octylamine, tri-n-butylamine, laurylamine, stearylamine, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, sodium or potassium alcoholates of C1 to C5, triethanolamine, choline, N-methylmorpholine, pyridine, dimethylaminopyridine, N,N'-dihydroxyethylethylenediamine, β-hydroxyethylethylenediamine, N-(2-hydroxyethyl)ethylenediamine, N,N,N',N'-tetrahydroxyethylethylenediamine, N-hydroxyethylpropylenediamine, trimethylhydroxyethylpropylenediamine, and N,N'-di(2-hydroxyethyl)-1,3-propylenediamine; and / or, the urea and its derivatives are 1,3-bis[3,5-bis(trifluoromethyl)phenyl]urea; And / or, when the first catalyst is a mixture of an organic base and one or more selected from urea and its derivatives, thiourea and its derivatives, the amount of the organic base is less than or equal to the amount of one or more selected from urea and its derivatives, thiourea and its derivatives.

6. The synthesis method according to claim 4, characterized in that The first reaction medium is one or more of tetrahydrofuran, TBD, benzene, toluene, xylene, dichlorobenzene, mesitylene, dichloromethane, chloroform, 1,2-dichloroethane, tetrahydropyrrole, tetrahydropyran, hexahydropyridine, ethyl acetate, ethyl ether, dimethyl ether, methyl ethyl ether, n-hexane, cyclohexane, cyclopentane, acetonitrile, dioxane, N,N-dimethylformamide and dimethyl sulfoxide; and / or, using a saturated benzoic acid tetrahydrofuran solution for the quenching; And / or, the purification method includes one or both of an anti-solvent method and a centrifugation method.

7. A polyester monomer recovery method according to claim 1 or 2, characterized in that: The method comprises: using a second catalyst to degrade the polyester and recovering the monomer δ-L.

8. The monomer recovery method according to claim 8, characterized in that: The second catalyst is one or more selected from inorganic salts and metal organic compounds; and / or, based on the amount of the polyester, the amount of the second catalyst added is 1 to 10%; And / or, the degradation reaction temperature is 60°C to 120°C.

9. Use of the polyester according to claim 1 or 2 as a reaction raw material in the preparation of polyurethane, characterized in that: The reaction raw materials also include isocyanate.

10. A polyurethane, characterized in that The polyester as claimed in claim 1 or 2 and isocyanate are reacted under the catalysis of a third catalyst to obtain the product.

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