Epoxide polymerization method, polymer having controlled carbon dioxide fraction and prepared thereby, and polymer having controlled molecular weight

Abstract

Disclosed are an epoxide polymerization method, a polymer having a controlled carbon dioxide fraction and prepared thereby, and a polymer having a controlled molecular weight. The epoxide polymerization method may comprise a step for polymerizing an epoxide or copolymerizing carbon dioxide and an epoxide in the presence of a epoxide polymerization catalyst including: a laminated thin film section containing a zinc-based material; and an organic compound inserted between thin films of the laminated thin film section, wherein the partial pressure of the carbon dioxide in the polymerization reaction system may be 0-150 bar, or a chain transfer agent (CTA) may be present in the polymerization reaction system.

Description

Epoxide polymerization method, polymer with controlled carbon dioxide fraction produced thereby, and polymer with controlled molecular weight

[0001] The present invention relates to an epoxide polymerization method, a polymer having a controlled carbon dioxide fraction produced thereby, and a polymer having a controlled molecular weight.

[0002] Anthropogenic carbon emissions are driving climate change, and a transition away from fossil fuel use in society and industry is necessary to prevent global catastrophe. Annual CO2 emissions reached 52.8 gigatonnes (Gt) in 2021, and to limit global warming to 2°C, these emissions must be reduced to below 17 Gt per year by 2050. However, considering the current high annual emissions and limited industrial CO2 utilization, achieving this goal appears to be a significant challenge. To address this issue, the development of new technologies capable of converting large amounts of CO2 into commercially valuable products is necessary. Replacing fossil fuel-based processes with sustainable CO2 utilization processes can contribute to achieving carbon neutrality.

[0003] Using CO2 as a carbon source in polymerization is a promising solution to reduce CO2 levels, given that significant amounts of CO2 can be consumed in the production of various plastic products. Carbon dioxide (CO2) utilization is gaining attention as a sustainable alternative to fossil fuel-based carbon sources in the production of industrial chemicals and polymers, offering a promising path to reducing dependence on fossil fuels and promoting the transition to a sustainable chemical industry. However, overcoming the thermodynamic and kinetic stability of CO2 and scaling up the process to large scale remain critical challenges for the commercialization of CO2-based technologies.

[0004] The polymerization of CO2 and epoxides has the potential to produce polymers with high CO2 content and diverse applications, making it a promising method for large-scale production. Polymers synthesized from CO2 and epoxides incorporate significant amounts of CO2 in their polycarbonate chains, and these polymers are utilized in a variety of commercial applications, including coatings, adhesives, and polyurethane formulations. The present invention recognizes the potential of these polymers to contribute to achieving carbon neutrality in various applications, which has stimulated research into the development of efficient homogeneous and heterogeneous catalysts.

[0005] Various studies have been conducted on homogeneous and heterogeneous zinc-based catalysts to enhance catalytic activity, increase the carbonate fraction, and reduce monomer carbonate formation. While heterogeneous catalysts offer economic advantages, a lack of understanding of the causes of catalytic activity has hindered the efficient development of zinc-based heterogeneous catalysts. Currently, the heterogeneous catalyst with the highest activity among catalysts for producing alternating polycarbonates from propylene oxide (PO) and CO2 is zinc glutarate (ZnGA), derived from ZnO and glutaric acid, with an activity of 0.85 kg / g-Zn. However, despite numerous attempts to enhance the catalytic activity of ZnGA, its catalytic activity remains insufficient for commercial polymerization processes.

[0006] The high CO2 content in the polymer poses a challenge for the commercialization of ZnGA, a catalyst for carbon dioxide and epoxide polymerization. When ZnGA is used to polymerize carbon dioxide and epoxide, the carbon dioxide content within the polymer chain exceeds 95%. This is a result of the 1:1 alternating polymerization of epoxide and carbon dioxide. However, the physical properties of polymers with high carbon dioxide content are hindering their commercialization. To achieve commercialization, it is necessary to lower the carbon dioxide content in the polymer to lower the glass transition temperature (Tg), thereby improving polymer processability and product properties. Currently, commercialized cobalt-zinc-based catalysts, such as double metal cyanide (DMC), can maintain carbon dioxide addition ratios within 30% in carbon dioxide-epoxide polymerization, and these polymers are used as polyurethane raw materials. However, no catalysts reported to date can freely control the carbon dioxide addition ratio from 0% to over 98%.

[0007] The present inventors recently reported Zn-gallate, a highly active zinc-based catalyst for the polymerization of carbon dioxide and propylene oxide (PO). Zn-gallate exhibits excellent catalytic activity, reaching up to 3.0 kg / g-cat (7.1 kg / g-Zn), surpassing that of zinc glutarate (0.85 kg / g-Zn), the previously reported best-performing zinc catalyst.

[0008] Furthermore, Zn-gallate produces high-molecular-weight polypropylene carbonate (PPC) while maintaining a high CO2 content (fCO2 = 97%). However, to expand the commercial applications of the resulting polymer, controlling the CO2 content (0-99%) and molecular weight is crucial. This allows for control of the thermal properties (Tg) of the polymer, thereby improving the processability and physical properties of the resulting polymer.

[0009] The present invention comprehensively investigates the mechanism of Zn-gallate-catalyzed copolymerization of PO and / or CO2, and the role of chain transfer agents (CTAs) in Zn-gallate-catalyzed PO copolymerization (Figs. 1a and 1b). In the absence of CTA, polymerization initiated at the Zn-gallate active site produces high-molecular-weight polymers, whereas the introduction of CTAs such as sebacic acid or methanol induces inert polymerization, forming low-molecular-weight polymers. Zn-gallate can promote PO and PO / CO2 inert polymerization by allowing various CTAs to interact with the active site and influence the catalyst properties. The present inventors report differences in the reactivity of alcohol-, carboxylic-, and amine-functionalized CTAs, and emphasize the importance of molecular weight control using CTAs through the possibility of synthesizing polyurethanes from hydroxyl-containing polypropylene carbonate (PPC-polyol). The present invention can contribute to the development of applications of CO2-derived polymers in the production of polyurethane and amphiphilic polymers.

[0010] One object of the present invention is to provide an epoxide polymerization method capable of controlling the carbon dioxide fraction (fCO2) or molecular weight, and a method for producing a polymer synthesized thereby.

[0011] In one aspect, the present invention provides a method for polymerizing an epoxide, comprising: a laminated thin film portion comprising a zinc-based material; and an organic compound inserted between thin films of the laminated thin film portion; and a step of polymerizing an epoxide or copolymerizing carbon dioxide and an epoxide in the presence of a catalyst for polymerizing an epoxide, wherein the partial pressure of the carbon dioxide in the polymerization reaction system is about 0 to 150 bar.

[0012] In one embodiment, the epoxide may include one or more substances selected from the group consisting of propylene oxide, ethylene oxide, cyclohexene oxide, butene oxide, hexene oxide, styrene oxide, Epichlorohydrin, allyl glycidyl ether, vinyl-propylene oxide, tert-butyl glycidyl ether, glycidol, octene oxide, analogs derived therefrom, and analogs substituted with functional groups therefrom.

[0013] In one embodiment, the partial pressure of the carbon dioxide in the polymerization reaction system may be less than 40 bar.

[0014] In another aspect, the present invention provides a method for polymerizing an epoxide, comprising a step of polymerizing an epoxide or copolymerizing carbon dioxide and an epoxide in the presence of a catalyst for epoxide polymerization, the method comprising: a laminated thin film portion comprising a zinc-based material; and an organic compound inserted between thin films of the laminated thin film portion; and a CTA (chain transfer agent) present in the polymerization reaction system.

[0015] In one embodiment, the organic compound may comprise gallate.

[0016] In one embodiment, the spacing between the thin films of the laminated thin film portion may be about 8 to 10 Å.

[0017] In one embodiment, the surface area of ​​the catalyst for epoxide polymerization may be about 150 to 165 m2 / g.

[0018] In one embodiment, the total volume of the catalyst for epoxide polymerization may be about 0.2 to 0.35 cm3 / g.

[0019] In one embodiment, the partial pressure of the carbon dioxide in the polymerization reaction system may be about 0 to 150 bar.

[0020] In one embodiment, the partial pressure of the carbon dioxide in the polymerization reaction system may be about 1 to 40 bar.

[0021] In one embodiment, the partial pressure of the carbon dioxide in the polymerization reaction system may be about 1 to 30 bar.

[0022] In one embodiment, the copolymer synthesized by the epoxide polymerization method may have an fCO2 of about 0.96 or less.

[0023] In one embodiment, the copolymer synthesized by the epoxide polymerization method may have an fCO2 of about 0 to 0.96.

[0024] In one embodiment, the copolymer synthesized by the epoxide polymerization method may have an fCO2 of about 0.72 or less.

[0025] In one embodiment, the copolymer synthesized by the epoxide polymerization method may have an fCO2 of about 0.03 to 0.72.

[0026] In one embodiment, the copolymer synthesized by the epoxide polymerization method may have a molecular weight of about 16,000 or less.

[0027] In one embodiment, the copolymer synthesized by the epoxide polymerization method may have a molecular weight of about 800 to 16,000.

[0028] In one embodiment, the copolymer synthesized by the epoxide polymerization method may have a molecular weight of about 800 to 3,000.

[0029] In one embodiment, the copolymer synthesized by the epoxide polymerization method may have a molecular weight of about 1,000 to 16,000.

[0030] In one embodiment, the copolymer synthesized by the epoxide polymerization method may have a molecular weight of about 5,900 to 16,000.

[0031] In one embodiment, the CTA may comprise a hydroxyl group, a carboxyl group, or an amine group.

[0032] In one embodiment, the CTA may comprise one or more substances selected from the group consisting of water, alcohols, diols, oligomers of diols, polymers of diols, carboxylic acids, dicarboxylic acids, amines, and aromatic amines.

[0033] In one embodiment, the CTA is water; methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, or decanol; methylene glycol, ethylene glycol, propylene glycol, butylene glycol, pentylene glycol, hexylene glycol, 1,6-hexanediol, heptylene glycol, octylene glycol, nonylene glycol, decylene glycol, or an oligomer or polymer thereof; glycerol, butanetriol, pentanetriol, hexanetriol, heptanetriol, octanetriol, nonanetriol, decanetriol; formic acid, acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, or decanoic acid; Oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimyl acid, azelaic acid, sebacic acid, nonandeiic acid, or decanedeiic acid; ammonia, methylamine, ethylamine, dimethylamine, propylamine, isopropylamine, ethylmethylamine, trimethylamine, butylamine, isobutylamine, secondary butylamine, tertiary butylamine, methylethylamine, diethylamine, methylpropylamine, triethylamine, pentylamine, isopentylamine, neopentylamine, hexylamine, isohexylamine, heptylamine, octylamine, nonylamine, or decylamine; Or it may include one or more substances selected from the group including aniline, toluidine, naphthylamine, benzidine, phenylenediamine, diphenylamine, triphenylamine, p-phenylenediamine, m-phenylenediamine, N-methylaniline, N,N-dimethylaniline, diazobenzene, or compounds in which at least one halogen is substituted on the benzene ring included in these.

[0034] In one embodiment, the CTA may comprise one or more substances selected from the group consisting of methanol, ethanol, propylene glycol, 1,6-hexanediol, adipic acid, sebacic acid, and 4,4'-methylene-bis(2-chloroaniline) (MOCA).

[0035] In another aspect, the present invention provides a polymer having a controlled carbon dioxide fraction, synthesized by an epoxide polymerization method according to the above-described embodiment of the present invention.

[0036] In another aspect, the present invention provides a polymer having a controlled molecular weight, synthesized by an epoxide polymerization method according to an embodiment of the present invention described above.

[0037] In another aspect, the present invention provides a method for polymerizing epoxide with a controlled carbon dioxide fraction, comprising a step of polymerizing epoxide or copolymerizing carbon dioxide and epoxide in the presence of a catalyst for epoxide polymerization, the method comprising: a laminated thin film portion comprising a zinc-based material; and an organic compound inserted between thin films of the laminated thin film portion; and setting the partial pressure of the carbon dioxide in the polymerization reaction system to a range derived according to the following equation (1).

[0038] 0.9×(41.3×fCO2 + 0.69) ≤ PCO2 (bar) ≤ 1.1×(41.3×fCO2 + 0.69) (1)

[0039] Here, fCO2 is the desired carbon dioxide fraction, and PCO2 is the partial pressure of carbon dioxide in the polymerization reaction system.

[0040] Through the epoxide polymerization method according to an embodiment of the present invention, the carbon dioxide fraction or molecular weight of the polymer to be synthesized can be controlled.

[0041] Figure 1a illustrates molecular weight controllable PO homopolymerization using a Zn-gallate catalyst.

[0042] Figure 1b illustrates molecular weight-controllable PO / CO2 copolymerization using a Zn-gallate catalyst.

[0043] FIG. 2 is a schematic drawing illustrating an example of the microstructure of a catalyst for epoxide polymerization used in an embodiment of the present invention.

[0044] Figure 3 is a diagram showing the reaction formula of carbon dioxide and propylene oxide in the presence of a Zn-gallate catalyst.

[0045] Figure 4 is an experimental example regarding the control of fCO2 according to carbon dioxide partial pressure.

[0046] Figure 5 is a graph showing the correlation between CO2 pressure and fCO2.

[0047] Figure 6 is a diagram showing a reaction formula under conditions without carbon dioxide.

[0048] Figure 7 is an example of a reaction experiment under conditions without carbon dioxide.

[0049] Figure 8 is a diagram showing the reaction formula of carbon dioxide and propylene oxide in the presence of CTA and Zn-gallate catalysts.

[0050] Figure 9 is an experimental example regarding molecular weight control of polymers according to CTA type.

[0051] Figure 10 is a diagram showing the molecular weight of a polymer produced in the absence of CTA.

[0052] Figure 11 illustrates the homopolymerization of PO over Zn-gallate catalysts in the presence of various CTAs. a: Reaction conditions: PO (150 mmol), Zn-gallate (0.5 mg / g-PO); b: Molar ratio; d: Mn and Mw / Mn values ​​were determined by SEC (THF).

[0053] Figure 12 shows the copolymerization of PO and CO2 over Zn-gallate catalysts in the presence of various CTAs. a: Reaction conditions: PO (150 mmol) used. b: Molar ratio. c: fCO2: {[PPC]} / {{[PPC] + [PPO]}} was determined by 1H NMR, selectivity: {[amount of PO incorporated into the polymer] / [propylene carbonate] + [amount of PO incorporated into the polymer]} was determined by 1H NMR. d: Mn and Mw / Mn values ​​were determined by SEC (THF).

[0054] Figure 13 (a) Photograph of the reaction mixture of Entry 1 of Figure 12 after polymerization, (b) Photograph of the reaction mixture of Entry 10 of Figure 12 after polymerization, (c) Photograph of the purified PPC from Entry 10 of Figure 12, (d) DOSY spectrum of PPC of Entry 10 of Figure 12, (e) MALDI-ToF analysis of PPC of Entry 11 of Figure 12.

[0055] Figure 14 (a) Relationship between Mn of polymer and [PO]0 / [MeOH]0, (b) DSC curves of polymers obtained from different [PO]0 / [MeOH]0, (c) Tg according to molecular weight (Mn) of polymer.

[0056] Figure 15a is a graph showing the catalytic activity as a function of polymerization time of a polymer depending on the presence or absence and type of CTA. Figure 15b is a diagram showing the change in molecular weight as a function of polymerization time of a polymer depending on the presence or absence and type of CTA.

[0057] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. The present invention may be modified in various ways and may take various forms. Therefore, specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, but should be understood to include all modifications, equivalents, and substitutes included in the spirit and technical scope of the present invention. In describing each drawing, similar reference numerals are used to indicate similar components. In the attached drawings, the dimensions of structures are shown larger than actual size to ensure clarity of the present invention.

[0058] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the terms "comprise" or "have" are intended to specify the presence of a feature, number, step, operation, component, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, or combinations thereof. In the context of this specification, the term "about" or the like can mean about ± 1%, about ± 2%, about ± 3%, about ± 4%, about ± 5%, about ± 6%, about ± 7%, about ± 8%, about ± 9%, or about ± 10% of a numerical value described in the specification.

[0059] Additionally, the description of one aspect of the present invention may be applied identically or similarly to the same or similar configurations or terms in the description of other aspects.

[0060] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0061] An epoxide polymerization method according to an embodiment of the present invention may include a step of polymerizing an epoxide or copolymerizing carbon dioxide and an epoxide in the presence of an epoxide polymerization catalyst, the catalyst comprising a laminated thin film portion including a zinc-based material; and an organic compound inserted between thin films of the laminated thin film portion.

[0062] In the context of this specification, a reaction expressed as polymerization or copolymerization may mean polymerization of epoxide alone in a carbon dioxide-free environment, or copolymerization of carbon dioxide and epoxide.

[0063] In one embodiment, the partial pressure of the carbon dioxide in the polymerization reaction system may be about 150 bar or less.

[0064] In one embodiment, the partial pressure of the carbon dioxide in the polymerization reaction system may be about 0 to 150 bar.

[0065] In one embodiment, the partial pressure of the carbon dioxide in the polymerization reaction system may be less than about 40 bar.

[0066] FIG. 2 is a schematic diagram illustrating a configuration of an epoxide polymerization catalyst used in an embodiment of the present invention. Referring to FIG. 2, an epoxide polymerization catalyst (100) according to an embodiment of the present invention may include a laminated thin film portion (110) including a zinc-based material; and an organic compound (120) inserted between the thin films of the laminated thin film portion (110).

[0067] The above-described laminated thin film portion (110) is a configuration including a zinc-based material. In the context of the present specification, a thin film may refer to a two-dimensional structure having a significantly thin thickness, and a laminate or laminated thin film may refer to a structure in which two or more of the thin films are arranged face to face with each other. As long as it does not deviate from the spirit of the present invention, the thickness of the thin film is not particularly limited, and the spacing between the laminated thin films is also not particularly limited. In one embodiment, the thickness of the laminated thin film portion (110) may be about 1 to 2 nm. In one embodiment, the spacing (110D) between the thin films of the laminated thin film portion may be about 8 to 10 Å.

[0068] In one embodiment, the laminated thin film portion (110) has the geometric characteristics described above in a solid state, and each thin film can be separated during a polymer reaction. As a result of AFM measurement, it was confirmed that nanoparticles with a thickness of 1 to 2 nm were observed. As in the case of EtOH, it was confirmed that a large number of particles less than 2 nm were found.

[0069] The above organic compound (120) is a material inserted between the thin films of the laminated thin film portion (110). By inserting the organic compound (120) between the thin films of the laminated thin film portion (110), a reaction site of the epoxide polymerization catalyst (100) according to at least an embodiment of the present invention can be formed, but this function does not necessarily limit the scope of the present invention.

[0070] Meanwhile, an epoxide polymerization method according to an embodiment of the present invention may include a step of polymerizing an epoxide or copolymerizing carbon dioxide and an epoxide in the presence of an epoxide polymerization catalyst, the catalyst comprising a laminated thin film portion including a zinc-based material; and an organic compound inserted between thin films of the laminated thin film portion.

[0071] As described above, in one embodiment, the laminated thin film portion of the catalyst for epoxide polymerization can be separated into ultra-thin nanoparticles within the reaction solution.

[0072] In one embodiment, a chain transfer agent (CTA) may be present in the polymerization reaction system.

[0073] In one embodiment, the organic compound may comprise gallate.

[0074] In one embodiment, the spacing between the thin films of the laminated thin film portion may be about 8 to 10 Å.

[0075] In one embodiment, the surface area of ​​the catalyst for epoxide polymerization may be about 150 to 165 m2 / g.

[0076] In one embodiment, the total volume of the catalyst for epoxide polymerization may be about 0.2 to 0.35 cm3 / g.

[0077] In one embodiment, the partial pressure of the carbon dioxide in the polymerization reaction system may be about 0 to 150 bar.

[0078] In one embodiment, the partial pressure of the carbon dioxide in the polymerization reaction system may be about 1 to 40 bar.

[0079] In one embodiment, the partial pressure of the carbon dioxide in the polymerization reaction system may be about 1 to 30 bar.

[0080] In one embodiment, the copolymer synthesized by the epoxide polymerization method may have an fCO2 of about 0.96 or less.

[0081] In one embodiment, the copolymer synthesized by the epoxide polymerization method may have an fCO2 of about 0 to 0.96.

[0082] In one embodiment, the copolymer synthesized by the epoxide polymerization method may have an fCO2 of about 0.72 or less.

[0083] In one embodiment, the copolymer synthesized by the epoxide polymerization method may have an fCO2 of about 0.03 to 0.72. In one embodiment, the copolymer synthesized by the epoxide polymerization method may have a molecular weight of about 16,000 or less. In one embodiment, the copolymer synthesized by the epoxide polymerization method may have a molecular weight of about 800 to 16,000. In one embodiment, the copolymer synthesized by the epoxide polymerization method may have a molecular weight of about 800 to 3,000. In one embodiment, the copolymer synthesized by the epoxide polymerization method may have a molecular weight of about 1,000 to 16,000. In one embodiment, the copolymer synthesized by the epoxide polymerization method may have a molecular weight of about 5,900 to 16,000.

[0084] In the above-described examples, in the case of PO homopolymer in the absence of CTA, a polymer having a molecular weight of about 100,000 is produced, and in the case of CO2 / PO copolymer in the absence of CTA, a polymer having a molecular weight in the range of about 86,000-1,610,000, for example, a polymer having a molecular weight of about 500,000, is produced. In this way, the production of polymers having a molecular weight of several thousand to several tens of thousands is possible due to CTA. This phenomenon will become clear in the examples to be described below.

[0085] In one embodiment, the CTA may comprise a hydroxyl group, a carboxyl group, or an amine group.

[0086] In one embodiment, the CTA may comprise one or more substances selected from the group consisting of monoalcohols such as methanol, ethanol, water, propylene glycol, diols such as 1,6-hexanediol which is a diol of the form HO-(CH₂)n-OH (n = 2-10, and more than 10 is also possible), triols such as glycerol, tetraols such as pentaerythritol ethoxylate (PEG4OH), poly(ethylene glycol) (PEG) having various molecular weights, oligomers / polymers of PPG and PEG having OH at the terminal, monocarboxylic acids such as acetic acid, benzoic acid, aliphatic diacids such as adipic acid and sebacic acid, aromatic diacids such as terephthalic acid, multi acids such as Kemp's triacid, and aromatic amines such as 2-chloroaniline and aniline.

[0087] Meanwhile, a polymer having a controlled carbon dioxide fraction according to an embodiment of the present invention can be synthesized by the epoxide polymerization method according to the embodiment of the present invention described above.

[0088] Meanwhile, a polymer having a controlled molecular weight according to an embodiment of the present invention can be synthesized by the epoxide polymerization method according to the embodiment of the present invention described above.

[0089] Meanwhile, a method for polymerizing an epoxide with a controlled carbon dioxide fraction according to an embodiment of the present invention may include a step of polymerizing an epoxide or copolymerizing carbon dioxide and an epoxide in the presence of a catalyst for epoxide polymerization, the catalyst including a laminated thin film portion including a zinc-based material; and an organic compound inserted between thin films of the laminated thin film portion; and the partial pressure of the carbon dioxide in the polymerization reaction system may be set to a range derived according to the following equation (1).

[0090] 0.9×(41.3×fCO2 + 0.69) ≤ PCO2 (bar) ≤ 1.1×(41.3×fCO2 + 0.69) (1)

[0091] Here, fCO2 is the desired carbon dioxide fraction, and PCO2 is the partial pressure of carbon dioxide in the polymerization reaction system.

[0092] The above equation (1) can be adjusted appropriately. For example, the above equation (1) can be adjusted to the following equation (1-1) or the following equation (1-2).

[0093] 0.95×(41.3×fCO2 + 0.69) ≤ PCO2 (bar) ≤ 1.05×(41.3×fCO2 + 0.69) (1-1)

[0094] 0.8×(41.3×fCO2 + 0.69) ≤ PCO2 (bar) ≤ 1.2×(41.3×fCO2 + 0.69) (1-2)

[0095] In practice, when a high fCO2 close to the upper limit, such as 0.95 or more or 0.98 or more, is desired, even if PCO2 is set to a value higher than the upper limit defined by the above equation (1), the increase in fCO2 rapidly decreases as it approaches 1, with 1 being the maximum value. In such cases, a method of setting PCO2 to a value higher than the upper limit defined by the above equation (1) is also clearly included in the scope of the present invention.

[0096] Hereinafter, embodiments of the present invention will be described. However, the embodiments described below are merely some embodiments of the present invention, and the scope of the present invention is not limited to the embodiments described below.

[0097] [[Synthesis of fCO2-controlled polymers]]

[0098] A polymer was synthesized by reacting carbon dioxide and propylene oxide in the presence of a zinc-gallate catalyst. 0.5 mg of the zinc-gallate catalyst was used per 1 g of propylene oxide. The reaction scheme is shown in Figure 3. The polymer was synthesized by varying the partial pressure of carbon dioxide, and fCO2 was controlled according to the partial pressure of carbon dioxide, as shown in Figure 4.

[0099] Based on the derived data, the correlation between CO2 pressure and fCO2 was investigated. Figure 5 is a graph depicting the correlation between CO2 pressure and fCO2. Referring to Figure 5, it can be confirmed that the operator can achieve the desired fCO2 by controlling the CO2 pressure. The correlation was confirmed as PCO2 = 41.3 × fCO2 + 0.69. The reaction equation under conditions without carbon dioxide is as shown in Figure 6.

[0100] The reaction results under conditions without carbon dioxide are shown as a comparative example in Fig. 7.

[0101] [[Synthesis of polymers with controlled molecular weight]]

[0102] A polymer was synthesized by reacting carbon dioxide and propylene oxide in the presence of CTA and a zinc-gallate catalyst. 0.5 mg of the zinc-gallate catalyst was used per 1 g of propylene oxide. The carbon dioxide partial pressure was set at 40 bar. The reaction scheme is shown in Figure 8.

[0103] Polymers were synthesized using different types of CTA, and the molecular weight was controlled according to the CTA, as shown in Figure 9. In Figure 9, Mn represents the number-average molecular weight, Mw / Mn represents the molecular weight distribution, and GPC represents gel permeation chromatography. It can be confirmed that only the molecular weight decreased without significant changes in activity, fCO2, and selectivity. The amount of propylene oxide in the reaction system is 150 mmol.

[0104] In the absence of CTA, polymers with very high molecular weights of approximately 500,000 are produced. This can be confirmed in Figure 10.

[0105] [[Further discussion]]

[0106] To elucidate the polymerization mechanism promoted by Zn-gallate, PO homopolymerization and PO / CO2 copolymerization were investigated in the presence and absence of various protic CTAs (Figs. 11 and 12). The PO homopolymerization without CTA showed high activity of 1.8 kg / g-cat with 102 kDa polypropylene oxide (PPO) (Fig. 11, Entry 1). The addition of sebacic acid decreased the molecular weight to 5.2 kDa (Fig. 11, Entry 2), but the catalytic activity was maintained at 1.6 kg / g-cat, and the polydispersity (Ð) showed a wide value. The GPC trace showed a long forward diffusion, indicating the presence of high molecular weight chains, suggesting that sebacic acid is less effective as a chain transfer agent than the intrinsic chain growth of PO. The sebacic acid loading was increased to 2 mol% to improve the chain transfer efficiency and achieve a more uniform polymer distribution. However, this resulted in a decrease in catalytic activity to 0.3 kg / g-cat due to a balance between catalyst deactivation by protic CTA and enhanced chain transfer. To evaluate the effect of the chain length of aliphatic dicarboxylic acids on catalytic performance, adipic acid and dodecanedioic acid were used. Both acids exhibited similar catalytic activities of 1.5 kg / g-cat and similar Ð values ​​(Fig. 11, entries 3 and 4).

[0107] Alcohol-based CTAs exhibited similar catalytic activity with a narrower Ð than carboxylic acids (Fig. 11, entries 5 to 9). Increasing the propylene glycol concentration to 2 mol% decreased the molecular weight from 6.5 kDa to 3.3 kDa and significantly improved the Ð value from 4.6 to 1.5 (Fig. 11, entries 6 and 7). This indicates that propylene glycol effectively promoted chain transfer without compromising the catalytic activity. In particular, 1,10-decanediol significantly promoted chain transfer, producing a polymer with Ð = 1.4 (Fig. 11, entry 8). Interestingly, water did not inhibit the catalytic activity, showing results similar to those of propylene glycol (Fig. 11, entries 6 and 10). 2-Chloroaniline (pKa = 11.3) was used to investigate the effect of pKa on CTA behavior. This can be compared with sebacic acid (pKa = 4.7) to evaluate the resistance of Zn-gallate to protic CTA. The catalytic activity remained constant at 1.8 kg / g-cat, but the polymer exhibited a relatively wide Ð (Entry 11). The two reactive hydrogens of 2-chloroaniline led to the formation of a 1:0.8 mixture of monoalkylated and dialkylated chloroaniline products. Inducing the polymerization using more basic aniline resulted in a catalytic activity of 2.0 kg / g-cat (Entry 12). Compared to 2-chloroaniline, the reaction involving aniline resulted in the formation of monoalkylated polymer chains as the main product (mono:di = 1:0.09). The glass transition temperature (Tg) of PPO is in a narrow range of -66 to -67°C, showing that it does not depend significantly on molecular weight or the presence of CTA.

[0108] Based on the results of the homopolymerization of PO (Fig. 11), the copolymerization of PO and CO2 was investigated. A notable initial observation was that the copolymerization reaction rate of PO and CO2 was slow, regardless of the addition of CTA. The homopolymerization of PO achieved a catalytic activity of 1.8 kg / g-cat within 4 h (Fig. 11, Entry 1), whereas the PO / CO2 copolymerization required 20 h to achieve the same catalytic activity (Fig. 12, Entry 1). This result is consistent with the difference in nucleophilicity between the Zn-alkoxide formed by the reaction of Zn-OH with PO and the Zn-carbonate formed by the reaction of CO2. Considering the effect of zinc species on the reaction rate, the effects of various CTAs (acids, alcohols, and amines) on the PO / CO2 copolymerization were investigated. Long-chain aliphatic acids, decanedioic acid, sebacic acid, and adipic acid were used to produce PPCs with molecular weights reduced to 16-25 kDa, while maintaining excellent catalytic activity up to 1.7 kg / g-cat (Fig. 12, entries 2 to 4). CTAs containing methanol and 1,10-decanediol exhibited high catalytic activity, high fCO2 values, and polymer selectivity over the monomeric cyclic carbonate, while exhibiting molecular weights similar to those of carboxylic acid-based CTAs (Fig. 12, entries 5 and 7). In contrast, the addition of propylene glycol adversely affected the polymerization, resulting in low catalytic activity, low fCO2 values, selectivity, and molecular weight (entry 6). Addition of ethylene glycol or water as CTAs was ineffective. To explore the effect of CTAs with amine functionality, 2-chloroaniline was used. The amino group, which carries two protons, was successfully incorporated into the polymer chain, resulting in a mixture of mono- and doubly alkylated products (1:0.44 ratio). When aniline was used as the CTA, the ratio of mono- and doubly alkylated products was 1:1.2. To reduce the molecular weight of the polymer, the amounts of sebacic acid and methanol added were increased.As the amount of sebacic acid added increased, a low-molecular-weight polymer was produced (Fig. 12, Entry 10). Even when 5 mol% methanol was added, polymerization was promoted while maintaining a low molecular weight and high catalytic activity (Fig. 12, Entry 11).

[0109] The reaction mixture containing high molecular weight PPC exhibited a gel-like viscosity in the absence of CTA (Figure 12, Entry 1, Figure 13a). In contrast, when sebacic acid was added (Figure 12, Entry 10), a liquid-like mixture containing low molecular weight PPC and residual PO appeared (Figure 13b). The colored liquid mixture containing catalyst residue and residual PO was easily separated into a colorless CO2-polyol through activated carbon adsorption or acid addition (Figure 13c). The presence of sebacic acid in the polymer was confirmed by two-dimensional diffusion order spectroscopy (DOSY) analysis. The DOSY spectrum of this polymer (Figure 12, Entry 10) exhibited a single diffusion coefficient, suggesting a homogeneous structure composed of PPC and sebacic acid units (Figure 13d). The 1H and 13C NMR spectra of the polymer with added sebacic acid confirmed the presence of sebacic acid within the polymer chains. To identify the chain end groups, MALDI-ToF analysis was performed on the polymer. A polymer with a low molecular weight containing methanol (Fig. 12, entry 11) was selected for MALDI-ToF analysis. The obtained spectrum showed distinct peaks corresponding to Mobserved (Da) = n × (PO-CO2) + CH3OH + Na+ (Fig. 13e).

[0110] To investigate the effect of CTA loading on polymer properties, we systematically varied the initial PO / methanol ratio in copolymerization studies. As shown in Figure 14a, a clear correlation exists between molecular weight and the initial PO / methanol ratio ([PO]0 / [MeOH]0), demonstrating that chain length can be effectively controlled by adjusting the relative amount of methanol. Incorporating methanol into the polymer structure significantly reduces the Tg from 30 °C to -0.7 °C (Figure 14b). Low-molecular-weight polymers exhibit a characteristically significantly reduced Tg (Figure 14c). The dotted line in Figure 14c shows that the Mn-Tg relationship closely follows the Fox-Flory equation.

[0111] The molecular weight was continuously monitored during the polymerization process. In the absence of CTA, the polymer reached a molecular weight of 159 kDa within 8 h and continued to increase to 413 kDa (Figure 15b). This rapid chain growth resulted in the formation of long-chain polymers in the early stages. Addition of methanol resulted in the formation of short-chain polymers (3.3 kDa at 8 h), indicating the effective participation of methanol in the early polymerization stages. The molecular weight then increased to 14.9 kDa at the end of the reaction. Compared to sebacic acid, sebacic acid initially formed a polymer with a molecular weight of 21.1 kDa, which then decreased slightly to 15.9 kDa at the end of the reaction. The molecular weights of the final polymers containing methanol and sebacic acid were similar. Detailed information on catalytic activity, fCO2, polymer formation selectivity, and molecular weight is provided in the supplementary material. The polydispersity index (Ð) was high at low conversions but gradually decreased as monomer consumption progressed. These changes in catalytic activity, molecular weight, and Ð highlight the important role of Zn species generated in the presence or absence of CTA in chain growth and chain transfer processes.

[0112] Unlike long-chain CTAs (acids and alcohols), short-chain diols such as 1,2-propanediol and ethylene glycol showed limited catalytic activity in PO / CO2 copolymerization (entry 6 in Figure 12). To investigate the effect of chain length, diols with different carbon chain lengths (1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol) were used. It was observed that the catalytic activity increased with increasing chain length. In contrast, PO homopolymerization using short-chain diols showed similar catalytic activity (entries 6, 7, and 9 in Figure 11).

[0113] Although the present invention has been described above with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various modifications and changes may be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below.

Claims

1. A step of polymerizing epoxide or copolymerizing carbon dioxide and epoxide in the presence of an epoxide polymerization catalyst, comprising a laminated thin film portion including a zinc-based material; and an organic compound inserted between thin films of the laminated thin film portion; In the above polymerization reaction system, the partial pressure of the carbon dioxide is 0 to 150 bar, or a CTA (chain transfer agent) is present in the polymerization reaction system. Epoxide polymerization method.

2. In paragraph 1, The organic compound comprises gallate. Epoxide polymerization method.

3. In paragraph 1, The spacing between the thin films of the above laminated thin film portion is 8 to 10 Å. Epoxide polymerization method.

4. In paragraph 1, The surface area of ​​the above epoxide polymerization catalyst is 150 to 165 m2 / g. Epoxide polymerization method.

5. In paragraph 1, The total volume of the catalyst for the above epoxide polymerization is 0.2 to 0.35 cm3 / g. Epoxide polymerization method.

6. In paragraph 1, The copolymer synthesized by the above epoxide polymerization method has an fCO2 of 0.96 or less. Epoxide polymerization method.

7. In paragraph 6, The copolymer synthesized by the above epoxide polymerization method has an fCO2 of 0 to 0.

96. Epoxide polymerization method.

8. In paragraph 1, The copolymer synthesized by the above epoxide polymerization method has a molecular weight of 16,000 or less. Epoxide polymerization method.

9. In paragraph 8, The copolymer synthesized by the above epoxide polymerization method has a molecular weight of 5,900 to 16,000. Epoxide polymerization method.

10. In paragraph 1, The above CTA contains a hydroxyl group, a carboxyl group or an amine group, Epoxide polymerization method.

11. In paragraph 10, The CTA is water; methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol or decanol; methylene glycol, ethylene glycol, propylene glycol, butylene glycol, pentylene glycol, hexylene glycol, 1,6-hexanediol, heptylene glycol, octylene glycol, nonylene glycol, decylene glycol, or an oligomer or polymer thereof; glycerol, butanetriol, pentanetriol, hexanetriol, heptanetriol, octanetriol, nonanetriol, decanetriol; formic acid, acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, or decanoic acid; Oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimyl acid, azelaic acid, sebacic acid, nonandeiic acid, or decanedeiic acid; ammonia, methylamine, ethylamine, dimethylamine, propylamine, isopropylamine, ethylmethylamine, trimethylamine, butylamine, isobutylamine, secondary butylamine, tertiary butylamine, methylethylamine, diethylamine, methylpropylamine, triethylamine, pentylamine, isopentylamine, neopentylamine, hexylamine, isohexylamine, heptylamine, octylamine, nonylamine, or decylamine; or at least one substance selected from the group consisting of aniline, toluidine, naphthylamine, benzidine, phenylenediamine, diphenylamine, triphenylamine, p-phenylenediamine, m-phenylenediamine, N-methylaniline, N,N-dimethylaniline, diazobenzene, 4,4'-methylene-bis(2-chloroaniline) (MOCA) or compounds in which at least one halogen is substituted on the benzene ring contained therein; Epoxide polymerization method.

12. Synthesized by the epoxide polymerization method according to Article 1, Polymers with controlled carbon dioxide fraction or molecular weight.

13. A step of polymerizing epoxide or copolymerizing carbon dioxide and epoxide in the presence of an epoxide polymerization catalyst, comprising a laminated thin film portion including a zinc-based material; and an organic compound inserted between thin films of the laminated thin film portion; Characterized in that the partial pressure of the carbon dioxide in the above polymerization reaction system is set to a range derived according to the following equation (1). Epoxide polymerization method with controlled carbon dioxide fraction: 0.9×(41.3×fCO2 + 0.69) ≤ PCO2 (bar) ≤ 1.1×(41.3×fCO2 + 0.69) (1) Here, fCO2 is the desired carbon dioxide fraction, and PCO2 is the partial pressure of carbon dioxide in the polymerization reaction system.

Images