A method for preparing polyester from aromatic dialdehyde

Abstract

The present invention belongs to the field of polymer synthesis technology, and specifically relates to a method for preparing polyester from aromatic dialdehydes. The method comprises: using a pincer-shaped ruthenium complex as a catalyst, reacting for 12-72 hours in the presence of a small amount of catalyst within a temperature range of 80-180°C, and catalyzing the polymerization of dialdehydes to prepare polyesters in high yield. The entire process does not require any additives such as acids or bases, and the monomer conversion rate is as high as over 90%. Compared to traditional polymerization methods, the process of the present invention creatively realizes the direct polymerization of dialdehydes, not only getting rid of the use of harmful reagents such as acylates, strong acids and strong bases, but also having maximum atomic utilization, high yield, greener and milder reaction conditions, low requirements for production equipment, and conforming to the green, efficient and safe production principles.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer synthesis, and particularly relates to a method for preparing polyester from aromatic dialdehyde. Background Art

[0002] As one of the most commonly used polymer materials, plastic has brought great convenience to human life. Polyester is one of the most commonly used plastics and is widely used in packaging, agriculture, medical and other fields. For example, PET is one of the five general-purpose plastics. However, the service life of plastics is usually short, and after a large amount of use, the accumulation of plastics causes environmental pollution. Common treatment methods such as landfill composting and incineration for energy recovery are not the best solutions from an environmental and economic perspective. Chemical recycling provides a new method for the treatment of waste plastics. Recycling polyester into monomers or high-value compounds by chemical means can effectively solve the problem of waste plastic disposal. Therefore, based on practicality and environmental considerations, it is of great significance to use a green method to synthesize recyclable polyesters with good properties.

[0003] Many new polyester materials have been developed and are widely used commercially, but their thermodynamic and mechanical properties still have shortcomings. For example, PLA has poor mechanical properties and is prone to breakage, while PBS is unstable and easily melts at high temperatures. Therefore, it is of great significance to synthesize polyesters with good thermal and mechanical properties.

[0004] Traditional polyester synthesis methods mainly rely on alcohols and acylating agents, with the addition of strong acids or strong bases, and are also accompanied by unnecessary by-products. This polycondensation reaction needs to be carried out under harsh conditions such as high temperature or even vacuum, which consumes a lot of energy and the resulting polymer has low molecular weight and uncontrollable molecular weight distribution. Ring-opening polymerization has also been widely studied as a method for synthesizing polyesters. By opening the ring of lactones, the atomic utilization rate can be improved, and polyester can be obtained by controllable polymerization. However, ring-opening polymerization requires the synthesis of complex cyclic lactone monomers, which is difficult to commercialize. Therefore, the development of a green, efficient, and widely applicable dialdehyde polymerization method can not only provide a new polymerization, but also expand the diversity of polyester monomers, which plays a vital role in the future realization of green and efficient synthesis of commercial polyesters.

[0005] Applying organic small molecule reaction coupling methods to macromolecular polymerization is a viable strategy. For example, in the field of small molecule dehydrogenative coupling, transition metal-based catalyst-catalyzed coupling reactions have been extensively studied. In 2008, Milstein's group first reported an acridine-PNP-ruthenium catalyst that could be effectively applied to the dehydration of alcohols and ammonia to produce secondary amines. Experiments demonstrated that furfural undergoes a Tischchenko coupling reaction in this system to produce esters, and the entire catalytic system can be fully recycled. Compared to the dehydrogenative coupling of alcohols, the Tischchenko coupling reaction of aldehydes is more rapid. Under relatively mild conditions, without the addition of any excess reagents, the addition of catalysts and monomers enables efficient and green synthesis of esters. In view of this, the present invention aims to apply this catalytic system to the synthesis of high-molecular-weight polymers for the first time. Compared to traditional synthesis methods, the present invention expands the use of dialdehydes as monomers to prepare high-molecular-weight polyesters in a more environmentally friendly and efficient manner. Summary of the Invention

[0006] To address the above-mentioned problems, the present invention provides a method for preparing polyester from aromatic dialdehydes, wherein a polyester of formula (V) is obtained by direct polymerization of the dialdehydes. This method supports the direct use of inexpensive commercial dialdehydes as monomers, avoids the use of harmful acylating agents, prepares the polyester under mild conditions, and does not require any additives such as acids or bases. This reaction is greener than traditional polymerization methods.

[0007] In order to solve the above technical problems of the present invention, the present invention provides the following technical solutions:

[0008] The present invention aims to provide a method for preparing polyester from aromatic dialdehyde, comprising the following steps: mixing an aromatic dialdehyde of formula (II) and / or formula (III), a ruthenium catalyst of formula (I) and an organic solvent, and heating the mixture at 80-180° C. for a reaction of 12-72 hours under an inert gas atmosphere to obtain polyester;

[0009] A preferred embodiment is as follows: in a nitrogen atmosphere glove box, an aromatic dialdehyde of formula (II) and / or formula (III) and a ruthenium catalyst of formula (I) are placed in a Schlenk reaction flask, an appropriate amount of organic solvent is added, the flask is sealed, and the glove box is removed. The reaction system is inertly protected by connecting a nitrogen balloon to the flask or slowly passing a nitrogen stream through the flask. The reaction is slowly heated to 80-180°C for 12-72 hours, and then cooled to room temperature after the reaction is completed to obtain the polyester.

[0010] Wherein, the molecular structures of formula (I), formula (II) and formula (III) are as follows:

[0011]

[0012] Wherein, L1 and L2 are independently selected from P(R 1 )2、P(OR 2)2、N(R 3 )2、SR 4 , OR 5 Any one of; L3 is selected from CO, P(R 1 )3、P(OR 2 )3、NO、R 6 CN, R 7 Any one of NC;

[0013] Ar 1 、Ar 2 is phenyl, naphthyl, anthracenyl, phenanthrenyl, pyrenyl, furyl, thienyl, thiazolyl, oxazolyl, pyridyl, pyrimidinyl, pyrazinyl, quinolyl, carbazolyl, acridinyl or an aryl group represented by formula (IV);

[0014] The molecular structure of formula (IV) is as follows:

[0015]

[0016] Among them, Ar 3 、Ar 4 are independently phenyl, naphthyl, anthracenyl, phenanthrenyl, pyrenyl, furanyl, thienyl, thiazolyl, oxazolyl, pyridinyl, pyrimidinyl, pyrazinyl, quinolyl, carbazolyl or acridinyl;

[0017] R 1 、R 2 、R 3 、R 4 、R 5 、R 6 、R 7 、R 8 Each is independently selected from a C1-C20 straight-chain alkyl group, a C1-C20 branched-chain alkyl group, a C3-C20 cycloalkyl group, a C1-C20 alkyl group containing a heteroatom or an unsaturated bond, or a C6-C20 aryl group.

[0018] Furthermore, in the formula (I), L1 and L2 are P(R 1 )2, L3 is CO;

[0019] Preferably, the P(R 1 )2 in R 1 It is isopropyl.

[0020] Furthermore, in the formula (II) and formula (III), Ar 1 、Ar 2 and independently an o-disubstituted phenyl group, an m-disubstituted phenyl group, a p-disubstituted phenyl group, a 1,4-disubstituted naphthyl group, a 9,10-disubstituted anthracenyl group, a 2,5-disubstituted furyl group, a 2,5-disubstituted thienyl group, or a 2,6-disubstituted pyridyl group.

[0021] Furthermore, in the formula (IV), R 8 -O(CH2) m O-, m is an integer from 2 to 10, Ar 3 、Ar 4 All are phenyl.

[0022] Furthermore, the molecular structure of the polyester is shown in formula (V),

[0023]

[0024] Among them, Ar 1 、Ar 2 are independently aryl; x, y, z, n are independently integers from 0 to 1000;

[0025] The polyester has a number average molecular weight of 1-1000 kg / mol and a molecular weight distribution of 1.1-3.0.

[0026] The polyester represented by formula (V) is prepared from a ruthenium catalyst represented by formula (I) and an aromatic dialdehyde represented by formula (II) and / or formula (III) in a homogeneous reaction system in an organic solvent.

[0027] Furthermore, in the formula (V), x, y, z, and n are independently integers of 0-100;

[0028] The polyester has a number average molecular weight of 5-300 kg / mol and a molecular weight distribution of 1.3-2.0.

[0029] Furthermore, the organic solvent is one or more of n-hexane, cyclohexane, benzene, toluene, p-xylene, m-xylene, o-xylene, chlorobenzene, anisole, hexamethyldisiloxane, mesitylene, tetrahydrofuran, 1,2-dimethoxyethane, 1,4-dioxane, diethylene glycol dimethyl ether, N,N-dimethylformamide, and dimethyl sulfoxide.

[0030] When the method of the present invention uses a mixed solvent, it includes an organic solvent system obtained by combining the above organic solvents in any proportion.

[0031] Furthermore, the amount of the ruthenium catalyst of formula (I) is 0.1-5.0% of the molar amount of the aromatic dialdehyde represented by formula (II) and / or formula (III).

[0032] Preferably, the amount of ruthenium catalyst used is 0.2%, 0.5%, 1.0%, 2.0% and 5.0% of the molar amount of the aromatic dialdehyde represented by formula (II) and / or formula (III).

[0033] Furthermore, the molar volume ratio (mol:L) of the aromatic dialdehyde represented by formula (II) and / or formula (III) to the organic solvent is 0.1-2.0:1.

[0034] Furthermore, the copolymerization of the aromatic dialdehydes represented by formula (II) and formula (III) is formed by mixing monomers of formula (II) and formula (III) in any proportion.

[0035] Aromatic dialdehyde monomers can be homopolymerized or copolymerized in any combination.

[0036] Beneficial effects of the present invention:

[0037] 1. The present invention achieves the direct polymerization of aromatic dialdehydes to prepare polyesters for the first time, providing a method for synthesizing high-molecular-weight polyesters. Using a pincer-shaped ruthenium complex as a catalyst, the present invention catalyzes the polymerization of dialdehydes to prepare polyesters in high yields in the presence of a small amount of catalyst within a temperature range of 80-180°C for 12-72 hours. The entire process does not require any acid or base additives, and the monomer conversion rate is as high as over 90%. Compared to traditional polymerization methods, the present invention's process creatively achieves direct polymerization of dialdehydes, eliminating the use of harmful reagents such as acylates, strong acids, and strong bases. Furthermore, it maximizes atomic utilization, achieves higher yields, and operates under greener, milder reaction conditions with lower requirements for production equipment, thus adhering to the principles of green, efficient, and safe production.

[0038] 2. The use of commercially available, inexpensive monomers, aromatic dialdehydes, in the reaction avoids environmental pollution or human harm caused by the use of acylating agents. The present invention investigated the organic solvent, reaction time, reaction temperature, and catalyst dosage and found that when toluene was used as the solvent, the temperature was 150°C, and the catalyst dosage was 1.0 mol%, the polyester obtained after a reaction time of 48 hours had a high yield and molecular weight.

[0039] 3. The entire process does not require any additives and has high atom economy, making it an environmentally friendly polymerization method.

[0040] 4. The method of the present invention has low production cost and great promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0042] Figure 1 The polyester obtained in Example 1 1HNMR spectrum;

[0043] Figure 2 This is the GPC curve of the polyester obtained in Example 1. DETAILED DESCRIPTION

[0044] To make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments. Where specific conditions are not specified in the examples, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art in the art. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0046] The catalyst used in the following examples is a dihydroacridinium pincer-type ruthenium complex RuH(AH-iPr-PNP)(CO)2, where AH is 9,10-dihydroacridinium and iPr indicates that the substituent on the P atom is diisopropyl. The catalyst was synthesized according to the literature method (J.Am.Chem.Soc.2010,132,14763-14765.).

[0047] Example 1: Preparation of polyester from terephthalaldehyde

[0048] In a glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (28.6 mg, 0.05 mmol), and toluene (3 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 150°C in an oil bath for 24 h. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, and the solid product was collected. The polyester was vacuum dried and weighed. The polyester yield was calculated to be 92.6%, and the molecular weight M of the obtained polyester was 1.34. n =58.8kg / mol. 1 HNMR spectrum see Figure 1 , the GPC curve of polyester is shown in Figure 2 .

[0049] Example 2: Preparation of polyester from terephthalaldehyde

[0050] In a glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (28.6 mg, 0.05 mmol), and anisole (3 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 150°C in an oil bath for 24 h. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, and the solid product was collected. The polyester was vacuum dried and weighed. The polyester yield was calculated to be 80.3%, and the molecular weight M of the obtained polyester was 1.34. n =45.5kg / mol.

[0051] Example 3: Preparation of polyester from terephthalaldehyde

[0052] In the glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (28.6 mg, 0.05 mmol), and 1,4-dioxane (3 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 150 ° C in an oil bath for 24 h. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, the solid product was collected, and the polyester was vacuum dried. After weighing, the polyester yield was calculated to be 66.5%, and the molecular weight M of the obtained polyester was 2.34%. n =8.6kg / mol.

[0053] Example 4: Preparation of polyester from terephthalaldehyde

[0054] In a glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (28.6 mg, 0.05 mmol), and hexamethyldisiloxane (3 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 150°C in an oil bath for 24 h. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, and the solid product was collected. The polyester was vacuum dried and weighed. The polyester yield was calculated to be 50.1%, and the molecular weight M of the obtained polyester was 2.34. n =9.3kg / mol.

[0055] Example 5: Preparation of polyester from terephthalaldehyde

[0056] In a glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (28.6 mg, 0.05 mmol), and n-hexane (3 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 150°C in an oil bath for 24 h. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, and the solid product was collected. The polyester was vacuum dried and weighed. The polyester yield was calculated to be 60.5%, and the molecular weight M of the obtained polyester was 2.34. n =5.2kg / mol.

[0057] Example 6: Preparation of polyester from terephthalaldehyde

[0058] In a glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (28.6 mg, 0.05 mmol), and cyclohexane (3 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 150°C in an oil bath for 24 h. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, and the solid product was collected. The polyester was vacuum dried and weighed. The polyester yield was calculated to be 69.8%, and the molecular weight M of the obtained polyester was 2.34. n =7.6kg / mol.

[0059] Example 7: Preparation of polyester from terephthalaldehyde

[0060] In a glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (28.6 mg, 0.05 mmol), and p-xylene (3 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 150°C in an oil bath for 24 h. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, and the solid product was collected. The polyester was vacuum dried and weighed. The polyester yield was calculated to be 85.1%, and the molecular weight M of the obtained polyester was 1.34. n =31.3kg / mol.

[0061] Example 8: Preparation of polyester from terephthalaldehyde

[0062] In a glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (28.6 mg, 0.05 mmol), and m-xylene (3 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 150°C in an oil bath for 24 h. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, and the solid product was collected. The polyester was vacuum dried and weighed. The polyester yield was calculated to be 88.6%, and the molecular weight M of the obtained polyester was 1.34. n =29.5kg / mol.

[0063] Example 9: Preparation of polyester from terephthalaldehyde

[0064] In a glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (28.6 mg, 0.05 mmol), and o-xylene (3 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 150°C in an oil bath for 24 h. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, and the solid product was collected. The polyester was vacuum dried and weighed. The polyester yield was calculated to be 83.5%, and the molecular weight M of the obtained polyester was 1.3747 W / m. n =35.3kg / mol.

[0065] Example 10: Preparation of polyester from terephthalaldehyde

[0066] In a glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (28.6 mg, 0.05 mmol), and chlorobenzene (3 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 150°C in an oil bath for 24 h. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, and the solid product was collected. The polyester was vacuum dried and weighed. The polyester yield was calculated to be 88.2%, and the molecular weight M of the obtained polyester was 1.34. n =41.6kg / mol.

[0067] Example 11: Preparation of polyester from terephthalaldehyde

[0068] In a glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (28.6 mg, 0.05 mmol), and mesitylene (3 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 150°C in an oil bath for 24 h. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, and the solid product was collected. The polyester was vacuum dried and weighed. The polyester yield was calculated to be 89.7%, and the molecular weight M of the obtained polyester was 1.34. n =46.5kg / mol.

[0069] Example 12: Preparation of polyester from terephthalaldehyde

[0070] In a glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (28.6 mg, 0.05 mmol), and dimethyl sulfoxide (3 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 150°C in an oil bath for 24 h. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, and the solid product was collected. The polyester was vacuum dried and weighed. The polyester yield was calculated to be 68.5%, and the molecular weight M of the obtained polyester was 2.37 %. n =8.8kg / mol.

[0071] Example 13: Preparation of polyester from terephthalaldehyde

[0072] In a glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (28.6 mg, 0.05 mmol), and N,N-dimethylformamide (3 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 150°C in an oil bath for 24 h. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, and the solid product was collected. The polyester was vacuum dried and weighed. The polyester yield was calculated to be 70.2%, and the molecular weight M of the obtained polyester was 1.34. n =16.5kg / mol.

[0073] Example 14: Preparation of polyester from terephthalaldehyde

[0074] In a glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (28.6 mg, 0.05 mmol), and diethylene glycol dimethyl ether (3 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 150°C in an oil bath for 24 h. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, and the solid product was collected. The polyester was vacuum dried and weighed. The polyester yield was calculated to be 38.4%, and the molecular weight M of the obtained polyester was 2.34%. n =6.1kg / mol.

[0075] Example 15: Preparation of polyester from terephthalaldehyde

[0076] In a glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (14.3 mg, 0.025 mmol), and toluene (3 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 150°C in an oil bath for 24 h. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, and the solid product was collected. The polyester was vacuum dried and weighed. The polyester yield was calculated to be 84.2%, and the molecular weight M of the obtained polyester was 1.34. n =12.5kg / mol.

[0077] Example 16: Preparation of polyester from terephthalaldehyde

[0078] In a glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (5.7 mg, 0.01 mmol), and toluene (3 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 150°C in an oil bath for 24 h. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, and the solid product was collected. The polyester was vacuum dried and weighed. The polyester yield was calculated to be 60.5%, and the molecular weight M of the obtained polyester was 2.34. n =6.5kg / mol.

[0079] Example 17: Preparation of polyester from terephthalaldehyde

[0080] In a glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (57.3 mg, 0.1 mmol), and toluene (3 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 150°C in an oil bath for 24 h. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, and the solid product was collected. The polyester was vacuum dried and weighed. The polyester yield was calculated to be 94.2%, and the molecular weight M of the obtained polyester was 1.34. n =31.9kg / mol.

[0081] Example 18: Preparation of polyester from terephthalaldehyde

[0082] In a glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (143 mg, 0.25 mmol), and toluene (3 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 150°C in an oil bath for 24 hours. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, and the solid product was collected. The polyester was vacuum dried and weighed. The polyester yield was calculated to be 90.1%, and the molecular weight of the obtained polyester was M. n =19.4kg / mol.

[0083] Example 19: Preparation of polyester from terephthalaldehyde

[0084] In a glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (28.6 mg, 0.05 mmol), and toluene (3 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 150°C in an oil bath for 48 hours. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, and the solid product was collected. The polyester was vacuum dried and weighed. The polyester yield was calculated to be 96.1%, and the molecular weight M of the obtained polyester was 96.1%. n =72.9kg / mol.

[0085] Example 20: Preparation of polyester from terephthalaldehyde

[0086] In a glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (28.6 mg, 0.05 mmol), and toluene (3 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 150°C in an oil bath for 72 hours. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, and the solid product was collected. The polyester was vacuum dried and weighed. The polyester yield was calculated to be 93.5%, and the molecular weight M of the obtained polyester was 93.5%. n =32.8kg / mol.

[0087] Example 21: Preparation of polyester from terephthalaldehyde

[0088] In a glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (28.6 mg, 0.05 mmol), and toluene (3 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 150°C in an oil bath for 12 hours. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, and the solid product was collected. The polyester was vacuum dried and weighed. The polyester yield was calculated to be 50.3%, and the molecular weight M of the obtained polyester was 2.37 %. n =6.5kg / mol.

[0089] Example 22: Preparation of polyester from terephthalaldehyde

[0090] In a glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (28.6 mg, 0.05 mmol), and toluene (3 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 120°C in an oil bath for 48 hours. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, and the solid product was collected. The polyester was vacuum dried and weighed. The polyester yield was calculated to be 60.2%, and the molecular weight M of the obtained polyester was 2.34. n =12.8kg / mol.

[0091] Example 23: Preparation of polyester from terephthalaldehyde

[0092] In a glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (28.6 mg, 0.05 mmol), and toluene (3 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 180°C in an oil bath for 48 hours. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, and the solid product was collected. The polyester was vacuum dried and weighed. The polyester yield was calculated to be 89.6%, and the molecular weight M of the obtained polyester was 1.3477 W / m. n =14.5kg / mol.

[0093] Example 24: Preparation of polyester from terephthalaldehyde

[0094] In a glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (28.6 mg, 0.05 mmol), and toluene (3 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 80°C in an oil bath for 48 hours. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, and the solid product was collected. The polyester was vacuum dried and weighed. The polyester yield was calculated to be 49.8%, and the molecular weight M of the obtained polyester was 2.34. n =6.5kg / mol.

[0095] Example 25: Preparation of polyester from terephthalaldehyde

[0096] In the glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (28.6 mg, 0.05 mmol), and toluene (2.5 mL) were transferred to a Schlenk reaction tube. After the container was sealed, it was removed from the glove box and connected to a balloon filled with nitrogen. It was heated to 150 ° C in an oil bath and reacted for 48 hours. After the reaction was completed, it was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, the solid product was collected, and the polyester was vacuum dried. After weighing, the polyester yield was calculated to be 93.3%, and the molecular weight M of the obtained polyester was 2.3%. n =45.6kg / mol.

[0097] Example 26: Preparation of polyester from terephthalaldehyde

[0098] In a glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (28.6 mg, 0.05 mmol), and toluene (10 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 150°C in an oil bath for 48 hours. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, and the solid product was collected. The polyester was vacuum dried and weighed. The polyester yield was calculated to be 85.8%, and the molecular weight M of the obtained polyester was 1.34. n =22.3kg / mol.

[0099] Example 27: Preparation of polyester from terephthalaldehyde

[0100] In a glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (28.6 mg, 0.05 mmol), and toluene (20 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 150°C in an oil bath for 48 hours. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, and the solid product was collected. The polyester was vacuum dried and weighed. The polyester yield was calculated to be 63.5%, and the molecular weight M of the obtained polyester was 2.3747 W / m. n =13.2kg / mol.

[0101] Example 28: Preparation of polyester from terephthalaldehyde

[0102] In a glove box, terephthalaldehyde (670 mg, 5 mmol), catalyst (28.6 mg, 0.05 mmol), and toluene (50 mL) were transferred to a Schlenk reaction tube. The container was sealed and removed from the glove box. A balloon filled with nitrogen was connected and the mixture was heated to 150°C in an oil bath for 48 hours. After the reaction was completed, the mixture was cooled to room temperature and the polyester product was dissolved in a small amount of tetrahydrofuran and then precipitated in methanol. The dissolution-precipitation was repeated three times, and the solid product was collected. The polyester was vacuum dried and weighed. The polyester yield was calculated to be 40.4%, and the molecular weight M of the obtained polyester was 2.34%. n =5.2kg / mol.

[0103] Based on the above examples, the optimal polymerization conditions were determined: using toluene as the solvent, a temperature of 150°C, and a catalyst dosage of 1.0 mol%. After a reaction time of 48 hours, the resulting polyester exhibited a high yield and molecular weight. The polymerization reactions of various monomers under these optimal conditions are summarized. The specific polymerization reactions of Examples 29-55 under these optimal conditions for various monomers are shown in Table 1.

[0104] Table 1: Polymerization of different monomers under optimal conditions

[0105]

[0106]

[0107] As can be seen from the data in Table 1, Examples 29-55 are applicable to different dialdehyde substrates and can prepare a variety of aromatic polyesters. Good results can be achieved over a wide range of time and temperature, while also enabling the synthesis of polyesters with high yields and substantial molecular weights using low catalyst dosages. In summary, the present invention enables the direct polymerization of various aromatic dialdehyde monomers under mild conditions, offering a more diverse monomer structure, a greener polymerization method, and improved atom economy compared to traditional polyesterification methods.

[0108] The above describes in detail some of the embodiments of this patent, but this patent is not limited to the above embodiments. Other variations or modifications can be made within the knowledge of ordinary technicians in this field. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A method for preparing polyester from aromatic dialdehydes, characterized in that: The method comprises the following steps: mixing an aromatic dialdehyde of formula (II) and / or formula (III), a ruthenium catalyst of formula (I) and an organic solvent, and heating the mixture at 120-180° C. for 24-72 hours under an inert gas atmosphere to obtain a polyester; Wherein, the molecular structures of formula (I), formula (II) and formula (III) are as follows: Among them, L1 and L2 are P(R 1 )2,P(R 1 )2 in R 1 is isopropyl; L3 is CO; Ar 1 、Ar 2 is phenyl, naphthyl, anthracenyl, phenanthrenyl, pyrenyl, furyl, thienyl, thiazolyl, oxazolyl, pyridyl, pyrimidinyl, pyrazinyl, quinolyl, carbazolyl, acridinyl or an aryl group represented by formula (IV); The molecular structure of formula (IV) is as follows: Among them, Ar 3 、Ar 4 are independently phenyl, naphthyl, anthracenyl, phenanthrenyl, pyrenyl, furanyl, thienyl, thiazolyl, oxazolyl, pyridinyl, pyrimidinyl, pyrazinyl, quinolyl, carbazolyl or acridinyl; R 1 、R 2 、R 3 、R 4 、R 5 、R 6 、R 7 、R 8 Each is independently selected from a C1-C20 straight-chain alkyl group, a C1-C20 branched-chain alkyl group, a C3-C20 cycloalkyl group, a C1-C20 alkyl group containing a heteroatom or an unsaturated bond, or a C6-C20 aryl group; The organic solvent is one or more of toluene, p-xylene, m-xylene, o-xylene, chlorobenzene, anisole, mesitylene, and N,N-dimethylformamide; The amount of the ruthenium catalyst of formula (I) is 0.5-5.0% by mole of the aromatic dialdehyde represented by formula (II) and / or formula (III); The molar volume ratio (mol:L) of the aromatic dialdehyde represented by formula (II) and / or formula (III) to the organic solvent is 0.25-2.0:

1.

2. The method according to claim 1, characterized in that In the formula (II) and formula (III), Ar 1 、Ar 2 and independently an o-disubstituted phenyl group, an m-disubstituted phenyl group, a p-disubstituted phenyl group, a 1,4-disubstituted naphthyl group, a 9,10-disubstituted anthracenyl group, a 2,5-disubstituted furyl group, a 2,5-disubstituted thienyl group, or a 2,6-disubstituted pyridyl group.

3. The method according to claim 1, characterized in that In the formula (IV), R 8 is -O(CH2)mO-, m is an integer from 2 to 10, Ar 3 、Ar 4 All are phenyl.

4. The method according to claim 1, wherein The molecular structure of the polyester is shown in formula (V), Among them, Ar 1 、Ar 2 are independently aryl; x, y, z, n are independently integers from 0 to 1000; The polyester has a number average molecular weight of 1-1000 kg / mol and a molecular weight distribution of 1.1-3.

0.

5. The method according to claim 4, characterized in that In the formula (V), x, y, z, and n are independently integers of 0-100; the number average molecular weight of the polyester is 5-300 kg / mol, and the molecular weight distribution is 1.3-2.

0.

6. The method according to claim 1, characterized in that The copolymerization of the aromatic dialdehydes represented by formula (II) and formula (III) is prepared by mixing monomers of formula (II) and formula (III) in any proportion.

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