Method for preparing recyclable polyester through dehydrogenation polymerization of diketone and primary diol
Through the catalytic transfer hydrogenation-dehydrogenation polymerization cascade reaction of diketone compounds and ruthenium catalysts, the problem of dependence on secondary diols in traditional polyester synthesis was solved, and the green, low-cost preparation and efficient closed-loop circulation of recyclable polyester were achieved.
Patent Information
- Application Number
- CN202510796968.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-16
- Publication Date
- 2025-09-05
AI Technical Summary
Traditional polyester synthesis technology relies on secondary diols as key monomers, resulting in high costs, ecotoxicity risks and low recycling efficiency. In addition, the material has poor degradability and is difficult to achieve a 'monomer-polymer-monomer' closed cycle.
Diketone compounds are used as comonomers, and ruthenium-based catalysts are used to carry out catalytic transfer hydrogenation-dehydrogenation polymerization cascade reaction, avoiding the secondary diol synthesis step and generating recyclable polyester. The only by-product is hydrogen, realizing a green and mild catalytic polymerization system.
It significantly reduces the cost of polyester preparation, avoids the use of harmful catalysts, realizes the efficient closed-loop cycle of "monomer-polymer-monomer", simplifies the production process, and is green and environmentally friendly.
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Figure CN120590614A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of recyclable polyester preparation and provides a method for preparing recyclable polyester by using commercial diketone instead of secondary diol as polymerization monomer through catalytic transfer hydrogenation-dehydrogenation polymerization cascade reaction. Background Art
[0002] In the field of functional modification of polyester materials, the mechanical strength, thermal stability and degradation controllability of the materials can be significantly improved through structural designs such as branched structures and cyclic groups. However, traditional polycondensation technology relies on secondary diols as key monomers, and its preparation process requires multiple steps such as halogenation and strong acid catalysis. It inevitably uses high-risk reagents such as cyanide and heavy metal catalysts, resulting in high costs for waste treatment and potential ecological toxicity risks. In addition, traditional polyester materials still have problems such as low degradability, difficulty in recycling and low recycling rates, making it difficult to achieve a closed "monomer-polymer-monomer" cycle. Therefore, there is an urgent need to provide a solution to improve the above problems.
[0003] The present invention addresses the problems of dependence on secondary diols in traditional polyester synthesis technology and low catalytic system circulation efficiency, and proposes a new green catalytic polymerization strategy. This method uses diketone compounds as comonomers and utilizes the dynamic hydrogen transfer ability of ruthenium-based catalysts to achieve in-situ efficient conversion of diketones to secondary diol intermediates (i.e., catalytic transfer hydrogenation reaction), thereby eliminating the secondary diol synthesis step in traditional processes, and the only by-product is hydrogen. This technology avoids the use of toxic and harmful reagents from the source, greatly reduces the cost of reactants, and constructs a new catalytic polymerization system that is efficient, environmentally friendly, and has excellent circulation performance, with significant innovation and application prospects. Summary of the Invention
[0004] The present invention aims to provide a method for preparing recyclable polyesters from diketones and primary diols through a catalytic transfer hydrogenation-dehydrogenation polymerization cascade reaction. This method can improve the technical route of traditional polyester synthesis that relies on pre-synthesized secondary diol monomers, avoid the use of harmful catalysts in traditional processes, and reduce the risk of process contamination. Furthermore, the present invention involves reactant diketone compounds that are inexpensive and readily available (for example, the market price of 2,5-hexanedione is 30% lower than that of secondary diol derivatives), the reaction is mild, and the catalytic polymerization system can achieve a closed-loop, efficient "monomer-polymer-monomer" cycle. This not only simplifies the production process and is environmentally friendly, but also provides new ideas and possibilities for the sustainable development of polyester materials.
[0005] In a first aspect, the present invention provides a method for preparing polyester by dehydrogenation polymerization of diketones and primary diols, comprising in situ converting a diketone compound into a secondary diol intermediate by catalytic transfer hydrogenation using a ruthenium catalyst in an inert atmosphere and solvent environment, and then reacting the intermediate with a primary diol compound to produce a polyester by dehydrogenation polymerization;
[0006] The diol compound includes the compound represented by formula I;
[0007]
[0008] The diketone compound includes at least one of the compounds shown in formula II-1 and the compounds shown in formula II-2:
[0009]
[0010] The structure of the polyester is shown in formula III-1 and III-2:
[0011]
[0012] Where R1 is C3-C 20 Straight chain alkyl and / or branched chain alkyl and / or cycloalkyl, C5-C 20 aryl and / or heteroaryl, R2 is C0-C 20 Straight chain alkyl and / or branched chain alkyl, C3-C 20 Cycloalkyl, C5-C 20 m1, m2 are independently selected from integers from 1 to 5; x1, x2, y1, y2, z1, z2, n1, n2 are independently selected from integers from 10-100.
[0013] The synthesis method provided by the present invention realizes a catalytic transfer hydrogenation-dehydrogenation polymerization cascade reaction of diketones and primary diols by introducing a diketone compound in combination with a ruthenium catalyst. The prepared polyester can be depolymerized to generate primary diol and secondary diol monomers under the ruthenium catalyst and hydrogen pressure. This method not only significantly reduces the preparation cost of the polyester, but also the entire cycle process only involves dehydrogenation and hydrogenation reactions, providing a new idea for the green and sustainable preparation of recyclable polyesters.
[0014] Optionally, the compound represented by formula I includes one of 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 1,4-cyclohexanedimethanol, and 1,4-benzenedimethanol; the diketone compound includes: 2,3-butanedione, 2,4-pentanedione, 2,5-hexanedione, 2,6-heptanedione, 1,3-cyclopentanedione, 1, One of 4-cyclohexanedione, [1,1'-dicyclopentyl]-2,2'-dione, progesterone, curcumadione, and androstenedione; and / or, the solvent includes one of n-hexane, cyclohexane, benzene, toluene, chlorobenzene, bromobenzene, p-xylene, m-xylene, o-xylene, anisole, mesitylene, tetrahydrofuran, 1,2-dimethoxyethane, 1,4-dioxane, diethylene glycol dimethyl ether, dimethylformamide, and dimethyl sulfoxide.
[0015] Optionally, the ruthenium catalyst is a pyridine-based pincer-type ruthenium complex [RuH(Cl)(PNN)(CO)], the molar ratio of the catalyst to the reactant is (1-50):1000; and / or the concentration of the reactant in the solvent environment is 0.05 mol / L-1.0 mol / L; the reaction time and reaction temperature are 1h-45h and 100°C-150°C, respectively; the inert atmosphere includes nitrogen and argon; wherein the PNN ligand is 2-(di-tert-butylphosphonomethyl)-6-(diethylaminomethyl)pyridine; and the reactants include primary diol compounds and diketone compounds.
[0016] Optionally, the number average molecular weight of the polyester is 1-100 kDa, and the molecular weight distribution of the polyester is 1.1-2.0.
[0017] In a second aspect, the present invention further provides a method for recovering polyester prepared by any of the above optional methods, comprising recovering primary diols and secondary diol compounds by hydrogenation and depolymerization of polyester in a hydrogen-containing atmosphere and a ruthenium catalyst.
[0018] Optionally, the pressure of the hydrogen-containing atmosphere is 1 MPa-5 MPa; and / or, the polyester is depolymerized at 105° C.-150° C.; and / or, the recovery rate of the diol compound is greater than or equal to 85%.
[0019] Optionally, the primary diol and secondary diol compounds include the secondary diol intermediate and / or the primary diol compound in the method according to any one of claims 1 to 4, and the primary diol and secondary diol compounds can be polymerized again to form polyester.
[0020] The beneficial effects of the present invention include:
[0021] (1) The present invention provides a method for preparing recyclable polyesters. In an inert atmosphere and solvent environment, a diketone compound is in situ converted into a secondary diol intermediate via catalytic transfer hydrogenation using a ruthenium catalyst. This intermediate then undergoes a dehydrogenative polymerization reaction with a primary diol compound to form a polyester. The entire process does not require any acidic reagents or other additives. Compared to traditional polymerization methods, the present invention process does not require the pre-synthesis of secondary diols, eliminates the use of harmful reagents such as acylates and strong acids, and has environmentally friendly and mild reaction conditions, with low requirements for production equipment, thus complying with the principles of environmentally friendly, efficient, and safe production.
[0022] (2) The preparation method of the recyclable polyester provided by the present invention uses diketone compounds as commercially available cheap reactants with low cost, and the only reaction by-product is hydrogen. It is an environmentally friendly polymerization method with great promotion value.
[0023] (3) The recyclable polyester provided by the present invention can not only be depolymerized in a hydrogen-containing atmosphere and a ruthenium catalyst to efficiently recover primary and secondary diol monomers, but they can also be further dehydrogenated to prepare polyesters with structures and properties equivalent to those of the original polymers, thereby achieving a "monomer-polymer-monomer" closed-loop efficient cycle, which is green and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 This is the H NMR spectrum of the original polyester obtained by dehydrogenation polymerization of 1,10-decanediol and 2,5-hexanedione;
[0025] Figure 2 This is the hydrogen nuclear magnetic resonance spectrum of the recycled polyester prepared by depolymerization of the original polyester, recycling monomers and then polymerizing them. DETAILED DESCRIPTION
[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be the common meanings understood by people with ordinary skills in the field to which the present invention belongs.
[0027] An embodiment of the present invention provides a method for preparing polyester by dehydrogenation polymerization of diketones and primary diols, comprising in situ converting a diketone compound into a secondary diol intermediate through catalytic transfer hydrogenation using a ruthenium catalyst in an inert atmosphere and solvent environment, and then reacting the intermediate with a primary diol compound to produce polyester by dehydrogenation polymerization.
[0028] Specifically, the primary diol compounds include compounds represented by formula I:
[0029]
[0030] The diketone compound includes at least one of the compounds shown in formula II-1 and the compounds shown in formula II-2:
[0031]
[0032] The structure of the polyester is shown in formula III-1 and III-2:
[0033]
[0034] Where R1 is C3-C 20 Straight chain alkyl and / or branched chain alkyl and / or cycloalkyl, C5-C 20aryl and / or heteroaryl, R2 is C0-C 20 Straight chain alkyl and / or branched chain alkyl, C3-C 20 Cycloalkyl, C5-C 20 m1, m2 are independently selected from integers from 1 to 5; x1, x2, y1, y2, z1, z2, n1, n2 are independently selected from integers from 10-100.
[0035] In fact, polyester synthesis involves introducing diketone compounds in combination with ruthenium catalysts for catalytic transfer hydrogenation to obtain secondary diol intermediates, which are then further dehydrogenated and polymerized with primary diol compounds under the catalytic action of ruthenium catalysts to generate recyclable polyesters, completing the catalytic transfer hydrogenation-dehydrogenation polymerization cascade reaction. The prepared polyester can be depolymerized under ruthenium catalysts and hydrogen pressure to generate primary diol and secondary diol monomers. This method not only significantly reduces the preparation cost of polyester, but also the entire cycle process only involves dehydrogenation and hydrogenation reactions, providing new ideas for the green and sustainable preparation of recyclable polyesters.
[0036] In some embodiments, the compound of formula I selected includes one of 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 1,4-cyclohexanedimethanol, and 1,4-benzenedimethanol; the diketone compound selected includes 2,3-butanedione, 2,4-pentanedione, 2,5-hexanedione, 2,6-heptanedione, and 1,3-cyclopentanedione. , 1,4-cyclohexanedione, [1,1'-dicyclopentyl]-2,2'-dione, progesterone, curcumadione, and androstenedione; the solvent environment used includes one of n-hexane, cyclohexane, benzene, toluene, chlorobenzene, bromobenzene, p-xylene, m-xylene, o-xylene, anisole, mesitylene, tetrahydrofuran, 1,2-dimethoxyethane, 1,4-dioxane, diethylene glycol dimethyl ether, dimethylformamide, and dimethyl sulfoxide.
[0037] In some embodiments, the ruthenium catalyst used is a pyridyl pincer-type ruthenium complex [RuH(Cl)(PNN)(CO)], with a catalyst-to-reactant molar ratio of (1-50):1000; the concentration of the reactants in the solvent environment is 0.05 mol / L-1.0 mol / L. Specifically, the PNN ligand is 2-(di-tert-butylphosphonomethyl)-6-(diethylaminomethyl)pyridine, and the reactants include a primary diol compound and a diketone compound.
[0038] In some embodiments, the primary diol compound and the diketone compound react over a ruthenium catalyst for 1 to 45 hours. In practice, the diketone compound used includes one of the compounds of Formula II-1 and II-2. The completion time for reactants of different structural formulas can vary.
[0039] In some embodiments, a primary diol compound and a diketone compound undergo a catalytic transfer hydrogenation-dehydrogenation polymerization reaction at 100°C-150°C. In practice, the reaction temperature may need to be adjusted appropriately to facilitate the reaction depending on the reactants involved or the solvent environment. Furthermore, during the catalytic transfer hydrogenation-dehydrogenation polymerization reaction, the diketone compound is converted in situ to a secondary diol intermediate using a ruthenium catalyst via catalytic transfer hydrogenation, with a conversion rate of 90-98%.
[0040] In some embodiments, the inert atmosphere during the reaction process includes nitrogen or argon. In fact, conducting the reaction in an inert atmosphere is beneficial to protecting the reaction system, such as preventing oxidation. Alternatively, a small amount of inert gas can be introduced into a closed environment while the reaction is carried out in a vacuum environment.
[0041] In some embodiments, the number average molecular weight of the prepared polyester is 1-100 kDa. In fact, when performing a polymerization reaction, the chain growth of the produced polyester varies depending on the reaction control conditions such as temperature, time, and reactants.
[0042] In some embodiments, the polyester has a molecular weight distribution of 1.1-2.0 and has a branched or cyclic structure.
[0043] In a second aspect, the present invention further provides a method for recycling polyester prepared by any of the optional methods of the above embodiments, comprising hydrogenating and depolymerizing the polyester in a hydrogen-containing atmosphere and using a ruthenium catalyst to recover primary and secondary diol compounds.
[0044] In fact, when polyester is hydrogenated and depolymerized to recover glycol compounds, hydrogen is required to participate in the reaction. In some embodiments, the pressure of the hydrogen-containing atmosphere during the reaction is 1MPa-5MPa. Maintaining the pressure environment is conducive to promoting the forward progress of the preparation reaction.
[0045] In some embodiments, the polyester is depolymerized at 105° C.-150° C. to recover primary diol and secondary diol compounds, and the recovery rate of the primary diol and secondary diol monomers is greater than or equal to 85%.
[0046] In some embodiments, the recovered primary and secondary diol compounds include the secondary diol intermediates and / or primary diol compounds described in any one of claims 1 to 4, and these primary and secondary diol compounds can be polymerized again to form polyesters. In fact, the polyester formed by polymerizing the primary and secondary diol monomers recovered from the hydrogenation depolymerization reaction has properties substantially identical to the original polyester, and the polymerization yield can reach as high as 89%, achieving a closed "monomer-polymer-monomer" cycle.
[0047] The Milstein catalyst used in the following examples is a pyridyl pincer-type ruthenium complex [RuH(Cl)(PNN)(CO)], where PNN is 2-(di-tert-butylphosphonomethyl)-6-(diethylaminomethyl)pyridine. The catalyst was synthesized according to a literature method (J. Am. Chem. Soc. 2005, 127, 31, 10840–10841).
[0048] Example 1
[0049] This Example 1 provides a method for polymerizing 1,10-decanediol and 2,5-hexanedione under a nitrogen atmosphere (connected to a nitrogen balloon), comprising: adding a Milstein catalyst (14.6 mg, 0.03 mmol) and potassium tert-butoxide (3.2 mg, 0.03 mmol) to a 25 mL reaction vessel in a glove box, then adding toluene (1.0 mL), and stirring the mixture at room temperature for 5 minutes to activate the catalyst; then adding 1,10-decanediol and 2,5-hexanedione (a total of 1 mmol, with a feed molar ratio of 80:20), sealing the container, and transferring it out of the glove box, stirring in an oil bath to heat the solution to 120° C.; stirring the reaction under a nitrogen atmosphere for 24 hours; cooling to room temperature, removing the reaction vessel from the oil bath, dissolving the generated polymer in 1-2 mL of tetrahydrofuran, and then precipitating it in 20-40 mL of methanol, and vacuum drying the polymer. The polyester yield is calculated to be 58%, and the number average molecular weight Mn of the obtained polyester is 7.7 kDa.
[0050] Example 2
[0051] This Example 2 provides a method for polymerizing 1,10-decanediol and 2,5-hexanedione under closed conditions, comprising: in a glove box, adding a Milstein catalyst (14.6 mg, 0.03 mmol) and potassium tert-butoxide (3.2 mg, 0.03 mmol) to a 25 mL reaction vessel, then adding toluene (1.0 mL), and stirring the mixture at room temperature for 5 min to activate the catalyst; then adding 1,10-decanediol and 2,5-hexanedione (a total of 1 mmol, with a feed molar ratio of 80:20), sealing the container, and transferring it out of the glove box, stirring in an oil bath to heat the solution to 120° C.; stirring and reacting for 24 h in a closed state; cooling to room temperature, removing the reaction vessel from the oil bath, dissolving the generated polymer in 1-2 mL of tetrahydrofuran, and then precipitating it in 20-40 mL of methanol, and vacuum drying the polymer. The polyester yield is calculated to be 51%, and the number average molecular weight Mn of the obtained polyester is 3.0 kDa.
[0052] Example 3
[0053] This Example 3 provides a method for polymerizing 1,10-decanediol and 2,5-hexanedione under nitrogen atmosphere and then vacuum conditions, comprising: adding a Milstein catalyst (14.6 mg, 0.03 mmol) and potassium tert-butoxide (3.2 mg, 0.03 mmol) to a 25 mL reaction vessel in a glove box, then adding toluene (2.0 mL), and stirring the mixture at room temperature for 5 minutes to activate the catalyst; then adding 1,10-decanediol and 2,5-hexanedione (1 mL in total); mol, with a feed molar ratio of 80:20), the container was sealed, and transferred out of the glove box. The solution was heated to 120° C. with stirring in an oil bath; the reaction was stirred for 12 h under a nitrogen atmosphere, and then the solvent was removed under reduced pressure and the reaction was carried out in vacuum for 12 h. The reaction was cooled to room temperature, the reaction container was removed from the oil bath, the resulting polymer was dissolved in 1-2 mL of tetrahydrofuran, and then precipitated in 20-40 mL of methanol. The polymer was dried in vacuum, and the polyester yield was calculated to be 68%. The number average molecular weight Mn of the obtained polyester was 10.4 kDa.
[0054] Example 4
[0055] This Example 4 provides a method for polymerizing 1,10-decanediol and 1,4-cyclohexanedione at 105°C, comprising: adding a Milstein catalyst (14.6 mg, 0.03 mmol) and potassium tert-butoxide (3.2 mg, 0.03 mmol) to a 25 mL reaction vessel in a glove box, then adding toluene (2.0 mL), and stirring the mixture at room temperature for 5 min to activate the catalyst; then adding 1,10-decanediol and 1,4-cyclohexanedione (a total of 1 mmol, with a feed molar ratio of 90:10), sealing the container, and transferring it out of the glove box, stirring in an oil bath to heat the solution to 105°C; stirring the reaction for 12 h under a nitrogen atmosphere, then removing the solvent under reduced pressure, and reacting in vacuum for 12 h; cooling to room temperature, removing the reaction vessel from the oil bath, dissolving the generated polymer in 1-2 mL of tetrahydrofuran, then precipitating it in 20-40 mL of methanol, and vacuum drying the polymer to obtain no copolyester.
[0056] Example 5
[0057] This Example 5 provides a method for polymerizing 1,10-decanediol and 1,4-cyclohexanedione at 120° C., comprising: adding a Milstein catalyst (14.6 mg, 0.03 mmol) and potassium tert-butoxide (3.2 mg, 0.03 mmol) to a 25 mL reaction vessel in a glove box, then adding toluene (2.0 mL), and stirring the mixture at room temperature for 5 minutes to activate the catalyst; then adding 1,10-decanediol and 1,4-cyclohexanedione (1 mmol in total) to the reaction mixture. l, with a feed molar ratio of 90:10), the container was sealed, transferred out of the glove box, and the solution was heated to 120°C with stirring in an oil bath; the reaction was stirred for 12 hours under a nitrogen atmosphere, and then the solvent was removed under reduced pressure and the reaction was carried out in a vacuum for 12 hours; the reaction was cooled to room temperature, the reaction container was removed from the oil bath, the resulting polymer was dissolved in 1-2 mL of tetrahydrofuran, and then precipitated in 20-40 mL of methanol. The polymer was dried in vacuo, and the polyester yield was calculated to be 71%. The number average molecular weight Mn of the obtained polyester was 10.7 kDa.
[0058] Example 6
[0059] This Example 6 provides a method for polymerizing 1,10-decanediol and 1,4-cyclohexanedione at 135° C., comprising: adding a Milstein catalyst (14.6 mg, 0.03 mmol) and potassium tert-butoxide (3.2 mg, 0.03 mmol) to a 25 mL reaction vessel in a glove box, then adding toluene (2.0 mL), and stirring the mixture at room temperature for 5 minutes to activate the catalyst; then adding 1,10-decanediol and 1,4-cyclohexanedione (1 mmol in total) to the reaction mixture. l, with a feed molar ratio of 90:10), the container was sealed, transferred out of the glove box, and the solution was heated to 135° C. with stirring in an oil bath; the reaction was stirred for 12 hours under a nitrogen atmosphere, and then the solvent was removed under reduced pressure and the reaction was carried out in a vacuum for 12 hours; the reaction was cooled to room temperature, the reaction container was removed from the oil bath, the resulting polymer was dissolved in 1-2 mL of tetrahydrofuran, and then precipitated in 20-40 mL of methanol. The polymer was dried in vacuo; the polyester yield was calculated to be 70%, and the number average molecular weight Mn of the resulting polyester was 9.9 kDa.
[0060] Example 7
[0061] This Example 7 provides a method for polymerizing 1,10-decanediol and 1,4-cyclohexanedione at 150°C, comprising: adding a Milstein catalyst (14.6 mg, 0.03 mmol) and potassium tert-butoxide (3.2 mg, 0.03 mmol) to a 25 mL reaction vessel in a glove box, then adding toluene (2.0 mL), and stirring the mixture at room temperature for 5 min to activate the catalyst; then adding 1,10-decanediol and 1,4-cyclohexanedione (a total of 1 mmol, with a feed molar ratio of 90:10), sealing the container, and transferring it out of the glove box, stirring in an oil bath to heat the solution to 150°C; stirring the reaction under a nitrogen atmosphere for 12 h, then removing the solvent under reduced pressure, and reacting in vacuum for 12 h; cooling to room temperature, removing the reaction vessel from the oil bath, dissolving the generated polymer in 1-2 mL of tetrahydrofuran, then precipitating it in 20-40 mL of methanol, and vacuum drying the polymer to obtain no copolyester.
[0062] According to the examples, the preferred polymerization conditions are: using toluene as solvent, a temperature of 120° C., a catalyst to reactant molar ratio of 3:100, and a polyester having a high yield and molecular weight obtained after a total reaction of 24 hours.
[0063] Specifically, a polymerization reaction was performed in 2 mL of solvent at 120°C with 1 mmol of reactants (1,10-decanediol and 2,5-hexanedione) and 0.03 mmol of catalyst and 0.03 mmol of potassium tert-butoxide. The polymer mass ratio, target product number average molecular weight, target product molecular weight distribution, and target product yield varied under varying reaction monomer feed molar ratios, reaction durations, and solvent composition conditions, as shown in Table 1 below. Preferably, a target product yield of 78% and a target product number average molecular weight Mn of 19.2 kDa were achieved with a reactant feed molar ratio of 90:10, a reaction duration of 24 hours, and the use of toluene as the solvent.
[0064] Table 1
[0065]
[0066] a De: 1,10-decanediol; HDN: 2,5-hexanedione. b Tol: toluene; 1,4-Dioxane: 1,4-dioxane; Anisole: anisole. c By 1 H NMR or 13 Polymer composition calculated from C NMR spectra. d Determined by gel permeation chromatography (GPC) using polystyrene as a standard. * No copolyester was obtained.
[0067] Specifically, a polymerization reaction was performed in 2 mL of toluene solvent at 120°C with 1 mmol of reactants (1,6-hexanediol or 1,8-octanediol and 2,5-hexanedione or 1,4-cyclohexanedione or progesterone) added to 0.03 mmol of catalyst and 0.03 mmol of potassium tert-butoxide. The reaction was performed with an 80:20 monomer feed molar ratio and a 24-h reaction duration. The differences in the mass ratio of the resulting polymer components, the number average molecular weight of the target product, the molecular weight distribution of the target product, and the yield of the target product are shown in Table 2 below.
[0068] Table 2
[0069]
[0070] a HDO: 1,6-hexanediol; 1,8-OD: 1,8-octanediol; CHD: 1,4-cyclohexanedione; PRO: progesterone.
[0071] Specifically, in 2 mL of toluene solvent, 1 mmol of reactants (1,10-decanediol and 1,4-cyclohexanedione or 1,4-cyclohexanediol) were added with 0.03 mmol of catalyst and 0.03 mmol of potassium tert-butoxide to undergo a polymerization reaction. The reaction monomer feed molar ratio, duration, solvent composition, reaction temperature, polymer component mass ratio, target product number average molecular weight, target product molecular weight distribution, and target product yield are shown in Table 3. Numbers 1-4 correspond to the four comparative examples described above, respectively. Under the conditions of a reaction monomer feed molar ratio of 90:10, a duration of 24 h, and a reaction temperature of 120° C., the target product yield reached 71%, and the target product number average molecular weight Mn=10.7 kDa.
[0072] Table 3
[0073]
[0074]
[0075] a CHD: 1,4-cyclohexanedione; Cy: 1,4-cyclohexanediol.
[0076] Specifically, in 2 mL of solvent, 1 mmol of reactant (1,10-decanediol and progesterone, 2,5-hexanediol, isosorbide or 2,3-butanediol) was added with 0.03 mmol of catalyst and 0.03 mmol of potassium tert-butoxide to undergo polymerization reaction, and the reaction monomer feed molar ratio, duration, solvent composition, reaction temperature, polymer component mass ratio, target product number average molecular weight, target product molecular weight distribution and target product yield are shown in Table 4 below.
[0077] Table 4
[0078]
[0079] a PRO: progesterone; Hd: 2,5-hexanediol; ISB: isosorbide; BDO: 2,3-butanediol.
[0080] Specifically, a depolymerization reaction was conducted on a polymer product obtained by polymerization of 1,10-decanediol and 2,5-hexanedione or 1,4-cyclohexanedione using 0.03 mmol of a ruthenium catalyst and 0.03 mmol of potassium tert-butoxide in a 2 mL toluene solution at a hydrogen pressure of 2 MPa and a temperature of 120°C. Under the same conditions, the hydrogen atmosphere was switched to a nitrogen or argon atmosphere, and the depolymerized monomers were reused for dehydrogenation polymerization. The reaction time was 24 hours. The polymer, isolated polymer yield, repolymerized polymer yield, repolymerized polymer number average molecular weight, and repolymerized polymer molecular weight distribution are shown in Table 5 below.
[0081] Table 5
[0082]
[0083] Specifically, the NMR spectra of the recyclable polyester prepared from 1,10-decanediol and 2,5-hexanedione are shown in Figure 2 , wherein a is the dehydrogenation polymerization of 1,10-decanediol and 2,5-hexanedione to prepare the original polyester; b is the depolymerization of the original polyester to produce monomers 1,10-decanediol and 2,5-hexanediol; c is the recycling and polymerization of 1,10-decanediol and 2,5-hexanediol monomers to prepare polyester; 1 H NMR spectrum (400 MHz, CDCl 3 , 25° C.).
[0084] While the embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations of these embodiments are possible. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as set forth in the claims. Furthermore, the invention described herein is susceptible to other embodiments and may be practiced or implemented in a variety of ways.
Claims
1. A method for preparing polyester by dehydrogenation polymerization of diketone and primary diol, characterized in that: include: In an inert atmosphere and solvent environment, a diketone compound is in situ converted into a secondary diol intermediate by catalytic transfer hydrogenation using a ruthenium catalyst. The intermediate then undergoes a dehydrogenation polymerization reaction with a primary diol compound to form a polyester. The primary diol compound includes a compound represented by formula I: The diketone compound includes at least one of the compounds shown in formula II-1 and the compounds shown in formula II-2: The structure of the polyester is shown in formula III-1 and III-2: Where R1 is C3-C 20 Straight chain alkyl and / or branched chain alkyl and / or cycloalkyl, C5-C 20 aryl and / or heteroaryl, R2 is C0-C 20 Straight chain alkyl and / or branched chain alkyl, C3-C 20 Cycloalkyl, C5-C 20 m1, m2 are independently selected from integers from 1 to 5; x1, x2, y1, y2, z1, z2, n1, n2 are independently selected from integers from 10-100.
2. The method according to claim 1, characterized in that The compound represented by formula I includes one of 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 1,4-cyclohexanedimethanol and 1,4-benzenedimethanol; the diketone compound includes 2,3-butanedione, 2,4-pentanedione, 2,5-hexanedione, 2,6-heptanedione, 1,3-cyclopentanedione, 1,4-cyclopentanedione, One of hexanedione, [1,1'-dicyclopentyl]-2,2'-dione, progesterone, curcumadione, and androstenedione; and / or, the solvent includes one of n-hexane, cyclohexane, benzene, toluene, chlorobenzene, bromobenzene, p-xylene, m-xylene, o-xylene, anisole, mesitylene, tetrahydrofuran, 1,2-dimethoxyethane, 1,4-dioxane, diethylene glycol dimethyl ether, dimethylformamide, and dimethyl sulfoxide.
3. The method according to claim 1, characterized in that The ruthenium catalyst is a pyridyl pincer-type ruthenium complex [RuH(Cl)(PNN)(CO)], the molar ratio of the catalyst to the reactant is (1-50):1000; and / or the concentration of the reactant in the solvent environment is 0.05 mol / L-1.0 mol / L, the reaction time and the reaction temperature are 1 h-45 h and 100° C.-150° C., respectively; the inert atmosphere includes nitrogen and argon; wherein the PNN ligand is 2-(di-tert-butylphosphonomethyl)-6-(diethylaminomethyl)pyridine; and the reactants include primary diol compounds and diketone compounds.
4. The method according to claim 1, wherein The number average molecular weight of the polyester is 1-100 kDa, and the molecular weight distribution of the polyester is 1.1-2.
0.
5. A polyester recovery method prepared by the method according to any one of claims 1 to 4, characterized in that: include: Polyester is hydrogenated and depolymerized in a hydrogen-containing atmosphere using a ruthenium catalyst to recover primary diol and secondary diol compounds.
6. The recycling method according to claim 5, characterized in that: The pressure of the hydrogen-containing atmosphere is 1 MPa-5 MPa; and / or the polyester is depolymerized at 105° C.-150° C.; and / or the recovery rate of primary diols and secondary diols is greater than or equal to 85%.
7. The method according to claim 5, characterized in that The primary diol and secondary diol compounds include the secondary diol intermediate and / or the primary diol compound in the method according to any one of claims 1 to 4, and the primary diol and secondary diol compounds can be polymerized again to form polyester.