Preparation method of bio-based isosorbide polycarbonate and ester exchange device used in preparation method
A two-step method for preparing bio-based isosorbide-based polycarbonate was developed. This method utilizes a solid alkali-supported KF/MgO catalyst and a transesterification reaction under pressure, which solves the problems of low molecular weight and poor color of products in traditional methods. This method achieves efficient and green preparation of high-performance polycarbonate.
Patent Information
- Application Number
- CN202411078076.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-07
- Publication Date
- 2026-02-10
AI Technical Summary
In the existing technology, when preparing isosorbide-type polycarbonate using dimethyl carbonate and isosorbide as raw materials, there are problems such as intermediate products being mostly single-sided products and low molecular weight of the final product. In addition, the traditional one-pot method results in a yellowish product color, making it difficult to prepare high molecular weight, high-performance polycarbonate.
Bio-based isosorbide-based polycarbonate was prepared using a two-step method. In the first step, the intermediate isosorbide carbonate was separated after transesterification. In the second step, self-condensation or co-condensation reaction was carried out using a solid base-supported KF/MgO catalyst and transesterification was performed under pressure. The yield was improved by combining secondary reflux and the addition of dimethyl carbonate.
The yield and molecular weight of isosorbide carbonate were improved, the reaction rate was enhanced, and a high molecular weight, high-performance copolymerized isosorbide polycarbonate was prepared, which reduced production costs and environmental pollution.
Smart Images
Figure BDA0004982927830000041 
Figure BDA0004982927830000071 
Figure HDA0004982927840000011
Abstract
Description
Technical Field
[0001] This invention relates to the fields of plastic processing and polymer synthesis technology, and more specifically, to a method for preparing bio-based isosorbide-based polycarbonate and the transesterification apparatus used therein. Background Technology
[0002] Bisphenol A-type polycarbonate (BPA-PC) has limited applications in food packaging and other fields due to the non-renewable nature and estrogenic effects of bisphenol A. In recent years, isosorbide (IS), as a bio-based, renewable, non-toxic monomer, has emerged as the most promising key raw material for replacing bisphenol A in polycarbonate synthesis. Isosorbide-based polycarbonate (IS-PC) synthesized using IS exhibits non-toxicity and excellent optical properties, scratch resistance, thermal stability, biodegradability, and biocompatibility, showing promising application prospects in packaging, automotive, electronics, and biomedicine.
[0003] Patent CN116693836A discloses a method for preparing polycarbonate using an alkaline molecular sieve catalyst. This method uses isosorbide and diphenyl carbonate as raw materials, and a melt transesterification reaction is carried out under the action of an alkaline molecular sieve catalyst to obtain IS-PC with high color. Although the above catalytic system can effectively solve the problems of catalyst residue, low molecular weight, and product color in isosorbide-based polycarbonate, this method is only applicable to the diphenyl carbonate system. It is worth noting that the diphenyl carbonate system produces a large amount of high-boiling-point byproduct phenol during the reaction, which not only affects the performance of the material but also poses a health hazard.
[0004] Dimethyl carbonate (DMC), as a green chemical, has attracted researchers' attention due to its short processing time and lower production cost. Using it as a raw material for the preparation and modification of isosorbide-containing polycarbonate (IS-PC) holds promise as a highly competitive approach. However, to date, the preparation and modification of IS-PC using the DMC method still faces numerous challenges. These include the hygroscopic nature of IS, significant steric hindrance, large differences in the activity of internal and external hydroxyl groups, the low boiling point of DMC, and the strong electrophilicity of the carbonyl and methyl carbons in DMC, leading to numerous byproducts in the transesterification reaction and resulting in poor polycondensation efficiency. Furthermore, traditional IS-PC preparation and copolymerization modification generally employ a one-pot method. While this method is simple, the resulting isosorbide-based polycarbonate is yellowish in color, and it is difficult to produce high-molecular-weight, high-performance isosorbide-based polycarbonate. Summary of the Invention
[0005] To address the technical problem that the intermediate products in the one-pot preparation of isosorbide-based polycarbonate using dimethyl carbonate and isosorbide as raw materials are mostly single-sided products (one end of isosorbide reacts with dimethyl carbonate) and the final product has a low molecular weight, this invention provides a two-step method for preparing bio-based isosorbide-based polycarbonate.
[0006] The two-step method for preparing bio-based isosorbide-based polycarbonate provided by the present invention includes: Step 1: Dimethyl carbonate and isosorbide undergo transesterification reaction, and after the reaction is completed, the intermediate isosorbide carbonate ester generated in the reaction solution is extracted; Step 2: The extracted intermediate isosorbide carbonate ester undergoes self-condensation reaction, or undergoes transesterification and co-condensation reaction with modified monomers.
[0007] The first step of this invention is to obtain the intermediate isosorbide carbonate, which is then separated before undergoing a polycondensation reaction. The isosorbide carbonate intermediate not only acts as a plasticizer, weakening intermolecular forces, lowering melting temperature and melt viscosity, improving plasticity, increasing elongation at break, and enhancing optical transmittance, but more importantly, the formation of the isosorbide carbonate intermediate effectively improves problems such as poor reaction rates during polymerization due to the low reactivity of isosorbide, thereby increasing the polycondensation reaction rate and preparing a high-molecular-weight, high-performance, and functionalized copolymerized isosorbide-based polycarbonate.
[0008] One of the objectives of this invention is to provide a method for preparing bio-based isosorbide-based polycarbonate.
[0009] The preparation method of the bio-based isosorbide-based polycarbonate includes the following steps:
[0010] (1) Isosorbide and dimethyl carbonate were subjected to a reflux reaction under a protective gas atmosphere, stirring conditions, and the action of catalyst A; after the reaction was completed, isosorbide carbonate (dicarboxymethyl isosorbide ester) was separated.
[0011] (2) Under a protective gas atmosphere, under stirring conditions, and with the action of catalyst B, the isosorbide carbonate undergoes self-condensation polymerization or the isosorbide carbonate undergoes transesterification and co-condensation polymerization with the modified monomer.
[0012] In both steps (1) and (2), the protective gas is preferably nitrogen.
[0013] The A and B in catalyst A and B are only used to distinguish the catalysts used in steps (1) and (2) and have no practical significance.
[0014] In step (1), the catalyst A is selected from one or more of lithium acetylacetonate, potassium carbonate, and solid base supported KF / MgO.
[0015] Under otherwise identical reaction conditions, changes in catalyst A significantly affected the yield of isosorbide carbonate. Compared to lithium acetylacetonate and potassium carbonate, solid base-supported KF / MgO as catalyst A resulted in a significantly higher yield of isosorbide carbonate.
[0016] The KF content (the percentage of potassium fluoride in the total mass of magnesium oxide and potassium fluoride) in solid alkali-supported KF / MgO can be arbitrary, preferably 20%-40%. Solid alkali-supported KF / MgO can be commercially available or prepared in-house; its preparation method is an existing method.
[0017] According to the embodiments disclosed in this invention, the solid alkali-supported KF / MgO can be 40-KF / MgO-500, wherein the mass content of KF is 40%, and the calcination temperature is 500℃. 40-KF / MgO-500 is prepared in-house according to this invention. The preparation method of 40-KF / MgO-500 is as follows:
[0018] Add 4g of KF to 6g of MgO, add 10g of deionized water, stir magnetically for three hours, and then place in a 100℃ oven to dry for 12 hours to obtain a solid. After grinding, put the solid powder into a muffle furnace and calcine at a set temperature of 500℃ for 5 hours to obtain catalyst 40-KF / MgO-500.
[0019] In step (1), the initial molar ratio of isosorbide to dimethyl carbonate is 1:(2-4), preferably 1:(3-4). The "initial molar ratio of isosorbide to dimethyl carbonate" refers to the molar ratio of the initial amounts of isosorbide and dimethyl carbonate used, excluding any additional dimethyl carbonate used.
[0020] In step (1), the mass ratio of isosorbide to catalyst A is 100:(0.001-1), preferably 100:(0.01-0.1).
[0021] In step (1), the temperature of the reflux reaction is 90-150°C, preferably 100-130°C.
[0022] In step (1), the pressure of the reflux reaction is 0.1 to 0.4 MPa, preferably 0.2 to 0.4 MPa. Here, 0.1 to 0.4 MPa does not include 0.1 MPa.
[0023] In step (1), the reflux reaction time is 1 to 15 hours, preferably 6 to 8 hours.
[0024] In step (1), the stirring speed of the reflux reaction is 100 to 800 rpm.
[0025] In step (1), an ester exchange reaction occurs between isosorbide and dimethyl carbonate to obtain isosorbide carbonate ester; the reaction formula is shown below.
[0026]
[0027] The isosorbide carbonate obtained in step (1) is separated and then undergoes a polycondensation reaction. The isosorbide carbonate obtained in step (1) is a two-sided product, which can effectively solve the problem of poor reaction rate during polymerization caused by the low activity of isosorbide, and improve the molecular weight and overall performance of copolymerized isosorbide polycarbonate.
[0028] In step (1), the separation method of isosorbide carbonate (bilateral product) may specifically include: filtering the reaction solution to remove catalyst A, and rotary evaporation to remove byproducts and unreacted raw materials to obtain isosorbide carbonate (bilateral product).
[0029] In step (1), isosorbide and dimethyl carbonate undergo a reflux reaction. Specifically, isosorbide and dimethyl carbonate undergo a transesterification reaction to produce isosorbide carbonate and methanol. Methanol forms an azeotrope with unreacted dimethyl carbonate. At the reaction temperature, the azeotrope and unreacted dimethyl carbonate evaporate from the reaction system in gaseous form. The evaporated gaseous azeotrope and unreacted dimethyl carbonate exothermically liquefy and are refluxed back into the reaction system.
[0030] In step (1), the transesterification reaction pressure (reflux reaction pressure) is 0.1–0.4 MPa (excluding 0.1 MPa). This pressure condition is higher than atmospheric pressure. That is, in the method of the present invention, the transesterification of isosorbide and dimethyl carbonate is carried out under pressure. Compared with the one-pot method of preparing polycarbonate by isosorbide and dimethyl carbonate under atmospheric or negative pressure conditions, the yield of isosorbide carbonate ester obtained by the method of the present invention is significantly improved.
[0031] To improve the yield of isosorbide carbonate (bilateral product) in step (1), step (1) may also include a secondary reflux step during the reflux reaction; the secondary reflux step includes: collecting the gaseous component at the top of the reflux, condensing the gaseous component to obtain a liquid component; returning a portion of the liquid component to the top of the reflux, and recovering the remainder.
[0032] Furthermore, the reflux ratio of the liquid component is adjusted to maintain the temperature at the top of the reflux at 40–70°C, thereby obtaining a higher yield of isosorbide carbonate; the reflux ratio refers to the ratio of the liquid component returned to the top of the reflux to the remaining liquid component.
[0033] To improve the yield of isosorbide carbonate (a two-sided product) in step (1), step (1) may further include the addition of dimethyl carbonate during the reflux reaction; the addition of dimethyl carbonate maintains the molar ratio of isosorbide to dimethyl carbonate in the reaction system at the initial molar ratio. For example, the addition of dimethyl carbonate maintains the molar ratio of isosorbide to dimethyl carbonate in the reaction system at 1:(2-4), preferably 1:(3-4).
[0034] In specific implementation schemes, one can choose either "secondary reflux" or "addition of dimethyl carbonate", or both "secondary reflux" and "addition of dimethyl carbonate" can be selected simultaneously to increase the yield of isosorbide carbonate (bilateral product) in step (1).
[0035] According to the embodiments disclosed in this invention, under the condition that the transesterification reaction pressure of isosorbide and dimethyl carbonate in step (1) is 0.1 to 0.4 MPa, preferably 0.2 to 0.4 MPa, "secondary reflux" and "addition of dimethyl carbonate" are carried out simultaneously during the reflux reaction, the yield of isosorbide carbonate ester (double product) can be as high as 92.63%.
[0036] In step (2), the catalyst B is selected from one or more of magnesium oxide, solid base supported KF / MgO, and ionic liquid catalysts. The ionic liquid catalyst is selected from one or more of tetraethylimidazolium ionic liquid, 1-butyl-3-methylimidazolium ionic liquid, tetrabutylphosphonium acetate ionic liquid, 1-ethyl-3-methylimidazolium lysine ionic liquid, 1-ethyl-3-methylimidazolium bromide ionic liquid, tetramethylhydroquinone ionic liquid, and tetramethylammonium arginine ionic liquid.
[0037] In step (2), the modified monomer is selected from one or more of diester, straight-chain diol diol, hydroquinone bis(hydroxyethyl) ether, resorcinol bis(hydroxyethyl) ether, bisphenol A, terephthalic acid diethanol, diether fluorene, and bisphenol fluorene.
[0038] The diester is selected from one or more of linear diesters, cycloesters, and aromatic diesters, and preferably from one or more of dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl ethyl carbonate, di-n-butyl carbonate, dipentyl carbonate, dihexyl carbonate, diheptyl carbonate, dioctyl carbonate, ditert-butyl dicarbonate, ethylene carbonate, propylene carbonate, trimethylene carbonate, diphenyl carbonate, dimethyl terephthalate, diethyl terephthalate, dimethyl oxalate, diethyl oxalate, dimethyl succinate, and diethyl succinate.
[0039] The straight-chain diol is selected from ester cyclohydric diols and aromatic diols, preferably from one or more of ethylene glycol, polyethylene glycol, butanediol, polybutanediol, pentanediol, polypentanediol, hexanediol, hexanediol, heptahydrate, polyheptanediol, octanediol, polyoctanediol, 1,4-cyclohexanediol, tricyclodecanediol, cyclohexanediol, tricyclododecanediol, dodecanecycloalkyldiol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and spirocyclodiol.
[0040] In step (2), the catalyst B accounts for 0.001-1 wt% of isosorbide carbonate, preferably 0.01-0.5 wt%.
[0041] In step (2), the molar ratio of the modified monomer to the isosorbide carbonate is (0.1-2):1, preferably (0.1-1):1.
[0042] In step (2), the stirring speed is 100-500 rpm, preferably 200 rpm.
[0043] In step (2), the temperature of the transesterification reaction is 90-150°C, preferably 100-130°C.
[0044] In step (2), the pressure of the transesterification reaction is atmospheric pressure.
[0045] In step (2), the transesterification reaction takes 1 to 15 hours, preferably 6 to 8 hours.
[0046] In step (2), the polycondensation temperature is 160-250°C, preferably 200-240°C.
[0047] In step (2), the pressure of the polycondensation reaction is 100-1000 Pa, preferably 100-200 Pa.
[0048] In step (2), the polycondensation time is 1 to 5 hours, preferably 2 to 4 hours.
[0049] In step (2), the isosorbide carbonate ester (bilateral product) obtained in step (1) undergoes a self-condensation reaction or the isosorbide carbonate ester (bilateral product) undergoes an ester exchange cocondensation reaction with the modified monomer. Taking the cocondensation reaction of isosorbide carbonate ester (bilateral product) with a straight-chain diol as an example, the reaction formula is as follows.
[0050]
[0051] A second objective of this invention is to provide an ester exchange apparatus used in the preparation method described in one of the objectives of the invention.
[0052] The ester exchange device includes: a reaction vessel, a diaphragm pump, a reflux condenser, a reflux ratio controller, and a recovery unit;
[0053] The top of the reactor is provided with a reflux port and a feed port; the bottom of the reactor is provided with a discharge port.
[0054] The reflux condenser is provided with a bottom inlet / outlet, a top outlet, and an upper inlet. Its upper inlet is located below its top outlet, and its bottom inlet / outlet is connected to the reflux port of the reactor. The top outlet of the reflux condenser is connected in sequence to the condenser and the reflux ratio controller, and then connected to the upper inlet of the reflux condenser.
[0055] The bottom outlet of the reflux ratio controller is connected to a recirculator.
[0056] Preferably, a diaphragm pump is installed on the feed inlet pipeline of the reactor.
[0057] According to the embodiments disclosed in this invention, the bottom of the condenser tower is higher than the top of the reactor; the condenser is higher than the top of the condenser tower.
[0058] The reactor can be any existing reactor capable of heating, pressurizing, and stirring, meeting the required reaction conditions. For example, the WHFS-2 reactor from Weihai Automation Reactor Co., Ltd. can be used. The reactor has a built-in stirring device, an external heating jacket, and is equipped with a feed port, reflux port, discharge port, and replenishment port. The feed port is covered, and the initial reactants are added to the reactor through this port. Protective gas is introduced into the reactor through the reflux port to purge air from the reactor, and the continued introduction of protective gas pressurizes the reactor. The reflux port is also used for the reflux of distilled gaseous and liquid components. The discharge port is used to collect the product. The replenishment port is used to add dimethyl carbonate during the reaction.
[0059] The diaphragm pump can be any existing type. For example, the DPMXS3 diaphragm pump from Depam (Hangzhou) Pump Industry Technology Co., Ltd. can be used. The inlet of the diaphragm pump is connected to a container filled with dimethyl carbonate, and the outlet of the diaphragm pump is connected to the feed port of the reactor, so that dimethyl carbonate is added to the reactor through the diaphragm pump.
[0060] The reflux reflux device can be any existing reflux reflux device used in reactors. The reflux reflux device includes a bottom inlet / outlet, a top outlet, and an upper inlet, with the upper inlet located below the top outlet. The bottom inlet / outlet connects to the reflux port of the reactor. Gaseous components within the reactor enter the reflux reflux device through the reactor's reflux port and the bottom inlet / outlet. The raw materials undergo a reflux reaction within the reactor and the reflux reflux device. The gaseous components that have passed through the reflux reflux device are collected from the top outlet of the reflux reflux device.
[0061] The condenser can be any existing type. The condenser inlet is connected to the top outlet of the reflux condenser. The gaseous components collected from the top outlet of the reflux condenser are condensed into liquid components by the condenser. The liquid components flow out from the outlet of the condenser.
[0062] The reflux ratio controller can be any existing type. For example, the NFB1-5.5YC reflux ratio controller from Shandong Tianda Experimental Instrument Co., Ltd. The condenser outlet is connected to the reflux ratio controller inlet; the reflux ratio controller outlet is connected to the upper inlet of the reflux condenser. The liquid components flowing out of the condenser outlet pass through the reflux ratio controller; a portion flows into the reflux condenser through the upper inlet, and the remainder flows into the recovery unit.
[0063] The recycler can be any type of container capable of collecting and storing liquid organic matter. The recycler is connected to the outlet of the reflux ratio controller.
[0064] In operation, isosorbide, dimethyl carbonate, and catalyst are added to the reactor through the feed port. Protective gas is introduced into the reactor through the reflux port to purge air from the reactor. The protective gas is then continuously introduced to pressurize the reactor until the required transesterification reaction pressure is reached. The reactor is then heated to the required transesterification reaction temperature. The agitator is then activated and set to the desired stirring speed. Isosorbide and dimethyl carbonate undergo a reflux reaction within the reactor and reflux vessel.
[0065] The flow of materials within the transesterification device includes: opening the reactor lid and adding isosorbide, dimethyl carbonate, and catalyst A into the reactor; a protective gas is introduced into the reactor through the reflux port, and isosorbide and dimethyl carbonate undergo a reflux reaction within the reactor and reflux condenser. During the reflux reaction, a gaseous component is collected from the top outlet of the reflux condenser. This gaseous component contains methanol produced by the transesterification reaction of isosorbide and dimethyl carbonate, forming an azeotrope with unreacted dimethyl carbonate, and some unreacted dimethyl carbonate. The collected gaseous component enters the condenser and is condensed into a liquid component. The liquid component exits the condenser and enters the reflux ratio controller. After adjusting the reflux ratio through the reflux ratio controller, part of the liquid component is refluxed back to the condenser, and the other part flows into the recovery unit for recycling. During the reflux reaction, the content of dimethyl carbonate in the reaction system is sampled and detected through the reactor outlet. Based on this content, dimethyl carbonate is added to the reactor through the reactor feed port using a diaphragm pump.
[0066] When the preparation method described in one of the invention objectives uses the ester exchange device described in the second of the invention objective, the "secondary reflux" includes: taking out a gaseous component from the top outlet of the reflux device, the taken out gaseous component enters the condenser and is condensed into a liquid component; the liquid component comes out of the condenser and enters the reflux ratio controller, and after adjusting the reflux ratio through the reflux ratio controller, part of the liquid component is returned to the condenser and the other part flows into the recovery device for recycling.
[0067] "Adjusting the reflux ratio of the liquid component to maintain the temperature at the top of the reflux reflux unit between 40 and 70°C" means adjusting the reflux ratio using a reflux ratio controller to maintain the temperature at the top outlet of the reflux reflux unit between 40 and 70°C.
[0068] "Adding dimethyl carbonate" includes adding dimethyl carbonate to the reactor via a diaphragm pump.
[0069] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0070] 1) The method described in this invention uses dimethyl carbonate and isosorbide as raw materials to prepare isosorbide carbonate esters. The melt transesterification method has mild reaction conditions, does not cause environmental pollution during the reaction process, and the reaction products do not contain toxic substances. It is an efficient, green, and low-cost method for preparing isosorbide carbonate esters.
[0071] 2) This invention discloses a two-step copolymerization modification method for preparing bio-based isosorbide-based polycarbonate. The two-step method is as follows: Step 1: Using dimethyl carbonate and isosorbide as raw materials, a transesterification reaction is carried out under suitable temperature and pressure. After separating the catalyst, dicarboxymethyl isosorbide ester (isosorbide carbonate ester) is obtained. Step 2: The obtained isosorbide carbonate ester is melt-transesterified with diols / esters, etc., under the action of a solid base catalyst to obtain copolymerized modified bio-based isosorbide-based polycarbonate. This invention prepares isosorbide carbonate ester (a two-sided product) as a bio-based intermediate in the first step. This not only weakens the intermolecular forces of the material, reduces the melting temperature and melt viscosity, improves the plasticity of the material, increases the elongation at break, and improves the optical transmittance of the material, but more importantly, the generation of the intermediate isosorbide carbonate ester (a two-sided product) can effectively improve the problem of poor reaction rate during polymerization caused by the low activity of isosorbide, and improve the polycondensation reaction rate, thereby preparing a high molecular weight, high-performance, and functionalized copolymerized isosorbide-based polycarbonate. In addition, isosorbide carbonate (a two-sided product) is easy to store, which facilitates subsequent polycondensation; the reactivity of isosorbide carbonate (a two-sided product) is higher than that of isosorbide, which lays the foundation for the subsequent synthesis and modification of polycarbonate.
[0072] 3) The first step of this invention is carried out under pressure. The pressure reaction can effectively reduce the amount of dimethyl carbonate used, improve reaction efficiency, increase the yield of the intermediate isosorbide carbonate (a bilateral product), save time, and reduce preparation costs. Therefore, this invention has significant scientific and practical value.
[0073] 4) The first step of this invention reduces and controls the loss of dimethyl carbonate by double reflux and adjusting the reflux ratio, thereby increasing the yield of the intermediate isosorbide carbonate (a two-sided product) and effectively saving raw material costs.
[0074] 5) In the first step of this invention, samples are taken at any time during the reaction to explore the degree of reaction and analyze its composition. The lost dimethyl carbonate can be replenished in time by a diaphragm pump, which minimizes the amount of dimethyl carbonate used while greatly increasing the reaction rate of transesterification and the yield of the intermediate isosorbide carbonate (bilateral product). Attached Figure Description
[0075] Figure 1 This is a schematic diagram of the ester exchange apparatus used in Embodiment 1 of the present invention; Figure 1 In the diagram, 1 is the reaction vessel, 2 is the diaphragm pump, 3 is the reflux condenser, 4 is the recovery unit, 5 is the condenser, and 6 is the reflux ratio controller.
[0076] Figure 2 Isosorbide carbonate ester prepared in Example 2 of this invention 1 H-NMR spectrum;
[0077] Figure 3 The isosorbide carbonate ester prepared in Example 2 of this invention 14 C-NMR spectrum;
[0078] Figure 4 The mass spectrum of isosorbide carbonate ester prepared in Example 2 of this invention;
[0079] Figure 5 The isosorbide-type polycarbonate prepared in Example 7 of this invention 1 H-NMR image
[0080] Figure 6 The copolymerized isosorbide-based polycarbonate prepared in Example 8 of this invention... 1 H-NMR image
[0081] Figure 7 The copolymerized isosorbide-based polycarbonate prepared in Example 9 of this invention... 1 H-NMR spectrum;
[0082] Figure 8The copolymerized isosorbide-based polycarbonate prepared in Example 10 of this invention... 1 H-NMR spectrum;
[0083] Figure 9 The copolymerized isosorbide-based polycarbonate prepared in Example 11 of this invention... 1 H-NMR spectrum;
[0084] Figure 10 The copolymerized isosorbide-based polycarbonate prepared in Example 12 of this invention... 1 H-NMR spectrum;
[0085] Figure 11 The copolymerized isosorbide-based polycarbonate prepared in Example 13 of this invention... 1 H-NMR spectrum;
[0086] Figure 12 The copolymerized isosorbide-based polycarbonate prepared in Example 14 of this invention... 1 H-NMR spectrum. Detailed Implementation
[0087] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.
[0088] Example 1
[0089] An ester exchange device, such as Figure 1 As shown, it includes: a reactor 1, a diaphragm pump 2, a reflux 3, a condenser 5, a reflux ratio controller 6, and a recovery unit 4.
[0090] Reactor 1 has a built-in stirring device and an external heating jacket. It also has a feed port, a reflux port, a discharge port, and a replenishment port. The feed port of reactor 1 is covered. Reflux device 3 includes a bottom inlet / outlet, a top outlet, and an upper inlet, with the upper inlet located below the top outlet.
[0091] The inlet of diaphragm pump 2 is connected to a container containing dimethyl carbonate. The outlet of diaphragm pump 2 is connected to the feed port of reactor 1. The reflux port of reactor 1 is connected to the bottom inlet and outlet of reflux 3. The top outlet of reflux 3 is connected to the inlet of condenser 5. The outlet of condenser 5 is connected to the inlet of reflux ratio controller 6. The outlet of reflux ratio controller 6 is connected to the upper inlet of reflux 3 and the recovery device 4. A protective gas is introduced into the reflux port of reactor 1, and the products of the transesterification reaction between isosorbide and dimethyl carbonate are collected through the outlet of reactor 1.
[0092] Example 2
[0093] Using the ester exchange device of Example 1, such as Figure 1 As shown.
[0094] 500g of isosorbide, 1kg of dimethyl carbonate (molar ratio 1:3.2), and lithium acetylacetonate catalyst were added to reactor 1. Reactor 1 was heated, and nitrogen gas was introduced into reactor 1 to displace the air and increase the pressure inside reactor 1. The stirring inside reactor 1 was then turned on, so that isosorbide and dimethyl carbonate could undergo transesterification reflux reaction under nitrogen atmosphere, 130℃, 0.3-0.4Mpa, and stirring speed of 500rpm.
[0095] During the transesterification reaction, samples were taken from the bottom outlet of the reactor every hour to analyze the content of dimethyl carbonate in the reaction system. Dimethyl carbonate was added to reactor 1 until the content of dimethyl carbonate in the reaction system reached the initial content of dimethyl carbonate at the beginning of the reaction.
[0096] During the transesterification reaction, the gaseous component is collected from the top of reflux 3 and condensed to obtain a liquid component; a portion of the liquid component is refluxed back into reflux 3; the remaining liquid component is recovered. The ratio of the liquid component refluxed to reflux 3 to the recovered liquid component (reflux ratio) is adjusted by reflux ratio controller 6 to maintain the top temperature of reflux 3 at 40-70℃.
[0097] The reaction was refluxed for 6 hours, then terminated. The catalyst was removed by vacuum filtration, and the filtrate was rotary evaporated to obtain a pale yellow oily liquid product. The pale yellow oily liquid product was purified by column chromatography. 1 H-NMR spectrum 14 The C-NMR spectrum and mass spectrum are shown in the following figures. Figure 2 , Figure 3 , Figure 4 As shown;
[0098] 1 HNMR (400MHz, CDCl3): d=5.09–5.04(m,2H),4.87(t,1H),4.53(d,1H),4.08–4.00(m,2H),3.93–3.85(m,2H),3.80(s,3H),3.78ppm(s,3H);
[0099] 14 C NMR (400MHz, CDCl3): d=155.14,154.82,85.88,81.25,80.90,76.81,73.26,70.52,55.18,55.14ppm;
[0100] HRMS(ESI)m / z:262.07.
[0101] Combination Figure 2 The hydrogen spectrum, Figure 3 carbon spectrum and Figure 4 Mass spectrometry confirmed that the pale yellow oily liquid, after purification by column chromatography, was a bilateral product of isosorbide carbonate (both ends of isosorbide reacted with dimethyl carbonate), with the following structural formula: Its molecular formula is: C 10 H 14 O8.
[0102] The total amount of dimethyl carbonate used was calculated to be 1.5 kg. Gas chromatography analysis showed that the isosorbide conversion rate was 96.99%; the methanol yield was 79.96%; and the yield of the isosorbide carbonate bilateral product was 71.36%.
[0103] Example 3
[0104] The preparation method in this embodiment is the same as in Example 2, except that potassium carbonate is used as a catalyst. Upon testing, the purified product by column chromatography was identical to that in Example 2, being a bilateral product of isosorbide carbonate, with the following structural formula: Its molecular formula is: C 10 H 14 O8.
[0105] Gas chromatography analysis showed that the isosorbide conversion rate was 99.95%, the methanol yield was 90.61%, and the yield of the isosorbide carbonate bilateral product was 86.53%.
[0106] Example 4
[0107] The preparation method in this embodiment is the same as in Example 2, except that a solid base-supported KF / MgO catalyst was used. Upon testing, the product purified by column chromatography was identical to that in Example 2, being a bilateral product of isosorbide carbonate, with the following structural formula: Its molecular formula is: C 10 H 14 O8.
[0108] Gas chromatography analysis showed that the isosorbide conversion rate was 99.99%, the methanol yield was 99.96%, and the yield of the isosorbide carbonate bilateral product was 92.63%.
[0109] A method for preparing a solid base-supported catalyst: 4g of KF was added to 6g of MgO, along with 10g of deionized water. After magnetic stirring for three hours, the mixture was placed in a 100℃ oven and allowed to dry for 12 hours to obtain a solid. The solid powder was then ground and placed in a muffle furnace and calcined at a set temperature of 500℃ for 5 hours to obtain catalyst 40-KF / MgO-500.
[0110] Example 5
[0111] The preparation method in this embodiment is the same as in Example 1, except that tetrabutyl titanate is used as the catalyst. Upon testing, the purified product by column chromatography was identical to that in Example 2, being a bilateral product of isosorbide carbonate, with the following structural formula: Its molecular formula is: C 10 H 14 O8.
[0112] Gas chromatography analysis showed that the isosorbide conversion rate was 33.18%, the methanol yield was 19.12%, and the isosorbide carbonate yield was 3.46%.
[0113] Example 6
[0114] 500g of isosorbide, 1.5kg of dimethyl carbonate, and lithium acetylacetone catalyst were added to a reaction vessel. The reaction vessel was heated, and nitrogen gas was introduced to displace the air and increase the pressure inside the vessel. Stirring was then started, allowing isosorbide and dimethyl carbonate to undergo transesterification and reflux reaction under a nitrogen atmosphere, at 130°C, a stirring speed of 500rpm, and atmospheric pressure. During reflux, the azeotrope of dimethyl carbonate and methanol was continuously collected. The reflux reaction was carried out for 6 hours. After the reaction was completed, the catalyst was removed by vacuum filtration, and the filtrate was rotary evaporated to obtain a pale yellow oily liquid product. Analysis showed that the product, after purification by column chromatography, had the same composition as in Example 2, being a bilateral product of isosorbide carbonate ester, with the following structural formula: Its molecular formula is: C 10 H 14 O8.
[0115] Gas chromatography analysis showed that the isosorbide conversion rate was 99.2%, the methanol yield was 48.5%, and the yield of the isosorbide carbonate bilateral product was 15.9%.
[0116] Example 7
[0117] The isosorbide carbonate ester prepared in Example 4 was added to a two-necked flask along with magnesium oxide catalyst (magnesium oxide catalyst accounted for 0.01 wt% of isosorbide carbonate ester). Polycondensation was initiated at 200°C. During the reaction, the pressure was gradually reduced until it dropped to 100 Pa, and the reaction was carried out for 2 hours to obtain the product.
[0118] product 1 H-NMR spectrum as shown Figure 5 As shown, the product is an isosorbide-type polycarbonate, with the following structural formula: The weight-average molecular weight of the isosorbide-based polycarbonate prepared by gel permeation chromatography was 47258 g / mol.
[0119] Example 8
[0120] Polyethylene glycol, isosorbide carbonate prepared in Example 4, and magnesium oxide catalyst were added to a two-necked flask. The transesterification reaction was carried out at 130°C for 2 hours under normal pressure and a nitrogen atmosphere. After heating to 200°C, a co-condensation reaction was initiated. During the co-condensation reaction, the pressure was gradually reduced until it reached 100 Pa, and the co-condensation reaction was continued for another 2 hours to obtain the product. Polyethylene glycol accounted for 20% of the total mass of isosorbide carbonate, and magnesium oxide catalyst accounted for 0.01 wt% of the isosorbide carbonate.
[0121] product 1 H-NMR spectrum as shown Figure 6 As shown, the product is a copolymerized isosorbide-based polycarbonate with the following structural formula: The weight-average molecular weight of the prepared copolymerized isosorbide-based polycarbonate, as determined by gel permeation chromatography, was 36798 g / mol.
[0122] Example 9
[0123] Triethylene glycol, isosorbide carbonate prepared in Example 4, and magnesium oxide catalyst were added to a two-necked flask. The transesterification reaction was carried out at 130°C for 2 hours under normal pressure and a N2 atmosphere. After heating to 200°C, a co-condensation reaction was initiated. During the co-condensation reaction, the pressure was gradually reduced until it reached 100 Pa, and the co-condensation reaction was continued for another 2 hours to obtain the product. The molar ratio of isosorbide carbonate to triethylene glycol was 3:1, and the magnesium oxide catalyst accounted for 0.01 wt% of the isosorbide carbonate.
[0124] product 1 H-NMR spectrum as shown Figure 7 As shown, the product is a copolymerized isosorbide-based polycarbonate with the following structural formula: The weight-average molecular weight of the copolymerized isosorbide-based polycarbonate prepared by gel permeation chromatography was 26593 g / mol.
[0125] Example 10
[0126] 1,8-Octanediol, isosorbide carbonate prepared in Example 4, and magnesium oxide catalyst were added to a two-necked flask. The transesterification reaction was carried out at 130°C for 2 hours under normal pressure and a N2 atmosphere. After heating to 200°C, a co-condensation reaction was initiated. During the co-condensation reaction, the pressure was gradually reduced until it reached 100 Pa, and the co-condensation reaction was continued for another 2 hours to obtain the product. The molar ratio of isosorbide carbonate to 1,8-octanediol was 3:1, and the magnesium oxide catalyst accounted for 0.01 wt% of the isosorbide carbonate.
[0127] product 1 H-NMR spectrum as shown Figure 8 As shown, the product is a copolymerized isosorbide-based polycarbonate with the following structural formula: The weight-average molecular weight of the copolymerized isosorbide-based polycarbonate prepared by gel permeation chromatography was 25549 g / mol.
[0128] Example 11
[0129] 1,4-cyclohexanediethanol, isosorbide carbonate prepared in Example 4, and magnesium oxide catalyst were added to a two-necked flask. The transesterification reaction was carried out at 130°C for 2 hours under normal pressure and a N2 atmosphere. After heating to 200°C, a co-condensation reaction was initiated. During the co-condensation reaction, the pressure was gradually reduced until it reached 100 Pa, and the co-condensation reaction was continued for another 2 hours to obtain the product. The molar ratio of isosorbide carbonate to 1,4-cyclohexanediethanol was 3:1, and the magnesium oxide catalyst accounted for 0.01 wt% of the isosorbide carbonate.
[0130] product 1 H-NMR spectrum as shown Figure 9 As shown, the product is a copolymerized isosorbide-based polycarbonate with the following structural formula: The weight-average molecular weight of the copolymerized isosorbide-based polycarbonate prepared by gel permeation chromatography was 28459 g / mol.
[0131] Example 12
[0132] Terephthalic acid, isosorbide carbonate prepared in Example 4, and magnesium oxide catalyst were added to a two-necked flask. The transesterification reaction was carried out at 130°C for 2 hours under normal pressure and a nitrogen atmosphere. After heating to 200°C, a co-condensation reaction was initiated. During the co-condensation reaction, the pressure was gradually reduced until it reached 100 Pa, and the co-condensation reaction was continued for another 2 hours to obtain the product. The molar ratio of isosorbide carbonate to terephthalic acid was 3:1, and the magnesium oxide catalyst accounted for 0.01 wt% of the isosorbide carbonate.
[0133] product 1 H-NMR spectrum as shown Figure 10As shown, the product is a copolymerized isosorbide-based polycarbonate with the following structural formula: The weight-average molecular weight of the copolymerized isosorbide-based polycarbonate prepared by gel permeation chromatography was 48497 g / mol.
[0134] Example 13
[0135] Diphenyl carbonate, isosorbide carbonate prepared in Example 4, and catalyst KF / MgO were added to a two-necked flask and subjected to transesterification reaction at 180°C for 2 hours under normal pressure and N2 atmosphere. After heating to 200°C, a co-condensation reaction was initiated. During the co-condensation reaction, the pressure was gradually reduced until it reached 100 Pa, and the co-condensation reaction was continued for another 2 hours to obtain the product. The molar ratio of isosorbide carbonate to diphenyl carbonate was 1:1, and the catalyst KF / MgO accounted for 0.01 wt% of the isosorbide carbonate.
[0136] product 1 H-NMR spectrum as shown Figure 11 As shown, the product is a copolymerized isosorbide-based polycarbonate with the following structural formula: The weight-average molecular weight of the copolymerized isosorbide-based polycarbonate prepared by gel permeation chromatography was 32794 g / mol.
[0137] Example 14
[0138] Dimethyl terephthalate, isosorbide carbonate prepared in Example 4, and magnesium oxide catalyst were added to a two-necked flask. The transesterification reaction was carried out at 180°C for 2 hours under normal pressure and a nitrogen atmosphere. After heating to 200°C, a co-condensation reaction was initiated. During the co-condensation reaction, the pressure was gradually reduced until it reached 100 Pa, and the co-condensation reaction was continued for another 2 hours to obtain the product. The molar ratio of isosorbide carbonate to dimethyl terephthalate was 1:1, and the magnesium oxide catalyst accounted for 0.01 wt% of the isosorbide carbonate.
[0139] product 1 H-NMR spectrum as shown Figure 12 As shown, the product is a copolymerized isosorbide-based polycarbonate with the following structural formula: The weight-average molecular weight of the copolymerized isosorbide-based polycarbonate prepared by gel permeation chromatography was 34547 g / mol.
[0140] The embodiments and product examples described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention shall fall within the protection scope defined by the claims of the present invention.
Claims
1. A method for preparing a bio-based isosorbide-based polycarbonate, characterized in that, The preparation method includes the following steps: (1) Isosorbide and dimethyl carbonate were refluxed under a protective gas atmosphere, stirring conditions and the action of catalyst A; isosorbide carbonate was separated after the reaction was completed. (2) Under a protective gas atmosphere, under stirring conditions, and with the action of catalyst B, the isosorbide carbonate undergoes a self-condensation reaction or the isosorbide carbonate undergoes an ester exchange and co-condensation reaction with the modified monomer. The protective gas is preferably nitrogen.
2. The preparation method according to claim 1, characterized in that, In step (1), The catalyst A is selected from one or more of lithium acetylacetonate, potassium carbonate, and solid base supported KF / MgO; or / and, The initial molar ratio of isosorbide to dimethyl carbonate is 1:(2-4), preferably 1:(3-4); or / and, The mass ratio of isosorbide to catalyst A is 100:(0.001-1), preferably 100:(0.01-0.1).
3. The preparation method according to claim 1, characterized in that, In step (1), The reflux reaction temperature is 90–150°C, preferably 100–130°C; or / and, The pressure of the reflux reaction is 0.1–0.4 MPa, preferably 0.2–0.4 MPa; or / and, The reflux reaction time is 1–15 h, preferably 6–8 h; or / and, The stirring speed for the reflux reaction is 100–800 rpm.
4. The preparation method according to claim 1, characterized in that, In step (1), During the reflux reaction, the gaseous component at the top of the reflux is collected, condensed, and a liquid component is obtained; a portion of the liquid component is returned to the top of the reflux, and the remainder is recovered.
5. The preparation method according to claim 1, characterized in that, In step (1), Adjust the reflux ratio of the liquid component to maintain the temperature at the top of the reflux at 40–70°C; The reflux ratio refers to the ratio of the liquid component that returns to the top of the reflux to the remaining liquid component.
6. The preparation method according to claim 1, characterized in that, In step (1), During the reflux reaction, dimethyl carbonate is added to maintain the molar ratio of isosorbide to dimethyl carbonate in the reaction system at the initial molar ratio.
7. The preparation method according to claim 1, characterized in that, In step (2), The catalyst B is selected from magnesium oxide, solid base supported KF / MgO, or ionic liquid catalysts; the ionic liquid catalyst is preferably selected from one or more of the following: tetraethylimidazolium ionic liquid, 1-butyl-3-methylimidazolium ionic liquid, tetrabutylphosphonium acetate ionic liquid, 1-ethyl-3-methylimidazolium lysine ionic liquid, 1-ethyl-3-methylimidazolium bromide ionic liquid, tetramethylhydroquinone ionic liquid, and tetramethylammonium arginine ionic liquid; or / and, The modified monomer is selected from one or more of diester, straight-chain glycol diol, hydroquinone bis(hydroxyethyl) ether, resorcinol bis(hydroxyethyl) ether, bisphenol A, terephthalic acid diethanol, diether fluorene, and bisphenol fluorene; The diester is selected from one or more of linear diesters, cycloesters, and aromatic diesters, and preferably from one or more of dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl ethyl carbonate, di-n-butyl carbonate, dipentyl carbonate, dihexyl carbonate, diheptyl carbonate, dioctyl carbonate, ditert-butyl dicarbonate, ethylene carbonate, propylene carbonate, trimethylene carbonate, diphenyl carbonate, dimethyl terephthalate, diethyl terephthalate, dimethyl oxalate, diethyl oxalate, dimethyl succinate, and diethyl succinate. The straight-chain diol is selected from ester cyclohydric diols and aromatic diols, preferably from ethylene glycol, polyethylene glycol, butanediol, polybutanediol, pentanediol, polypentanediol, hexanediol, heptanediol, heptanediol, octanediol, polyoctanediol, etc.; 1,4-cyclohexanediethanol, tricyclodecanediethanol, cyclohexanediol, tricyclododecanediethanol, dodecanecycloalkyldiol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and spirocyclodiol.
8. The preparation method according to claim 1, characterized in that, In step (2), The catalyst B accounts for 0.001–1 wt% of isosorbide carbonate, preferably 0.01–0.5 wt%; or / and, The molar ratio of the modified monomer to the isosorbide carbonate is (0.1-2):1, preferably (0.1-1):
1.
9. The preparation method according to claim 1, characterized in that, In step (2), The stirring speed is 100–500 rpm; or / and, The transesterification reaction is carried out at a temperature of 90–150°C, preferably 100–130°C; or / and, The transesterification reaction was carried out at atmospheric pressure. The transesterification reaction takes 1–15 hours, preferably 6–8 hours; or / and, The polycondensation reaction is carried out at a temperature of 160–250°C, preferably 200–240°C; or / and, The pressure of the polycondensation reaction is 100–1000 Pa, preferably 100–200 Pa; or / and, The polycondensation reaction takes 1 to 5 hours, preferably 2 to 4 hours.
10. A transesterification device used in the preparation method according to claims 1-9, characterized in that, The ester exchange device includes: a reaction vessel, a reflux condenser, a reflux ratio controller, and a recovery unit; The top of the reactor is provided with a reflux port and a feed port; the bottom of the reactor is provided with a discharge port. The reflux condenser is provided with a bottom inlet / outlet, a top outlet, and an upper inlet. Its upper inlet is located below its top outlet, and its bottom inlet / outlet is connected to the reflux port of the reactor. The top outlet of the reflux condenser is connected in sequence to the condenser and the reflux ratio controller, and then connected to the upper inlet of the reflux condenser. The bottom outlet of the reflux ratio controller is connected to a recirculator; Preferably, a diaphragm pump is installed on the feed inlet pipeline of the reactor.