Method for preparing bio-based dihydric alcohol carbonate polyester based on waste electrolyte
The bio-based carbonate diol polyester is prepared by reacting bio-based diol with waste electrolyte, which solves the problems of electrolyte treatment of waste lithium battery and improves the performance of polyester, and achieves efficient recycling and performance enhancement effects.
Patent Information
- Application Number
- CN202510400264.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-01
- Publication Date
- 2025-07-04
AI Technical Summary
How to efficiently and harmlessly treat waste lithium battery electrolyte, improve the thermal stability and mechanical properties of polyester, while ensuring its biodegradability.
Bio-based diol is used to react with carbonate solvents in the waste electrolyte, and bio-based carbonate diol monomer is prepared through a supergravity reactor, and polymerize it with dibasic acid to form bio-based carbonate diol polyester, and react under controlled conditions using a supergravity reactor and a specific catalyst.
It improves the recovery rate of waste electrolyte, enhances the mechanical and thermal properties of polyester, and ensures its biodegradability, providing a high-value utilization solution for polyester materials.
Smart Images
Figure CN120248298A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of polymer materials, and particularly relates to a method for preparing bio-based carbonated diol polyester from waste electrolyte. Background Art
[0002] At present, the domestic production of lithium batteries in China is increasing year by year. Then, with the increase in the production of lithium batteries, the corresponding number of waste lithium batteries also increases. How to efficiently and harmlessly treat waste lithium battery electrolyte has become a problem. Carbonate alkyl ester solvents play an important role in electrolytes. It forms an electrolyte together with other raw materials such as solutes and additives. However, the content of the solvent is the highest, generally 80 - 85%, the lithium salt is 8 - 15%, and the additive accounts for 1 - 5%.
[0003] Transesterification is an important chemical reaction and is widely used in various fields of petrochemical production. The production of dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, etc. and the synthesis of downstream products are of particularly important significance. With the gradual reduction of petroleum resources and the enhancement of people's environmental protection awareness, the chemical industry based on renewable raw materials has developed rapidly. By studying the development methods of renewable resources, the maximum utilization of natural resources is achieved.
[0004] In polyester materials, polyesters prepared from petroleum-based raw materials have been applied in all aspects of life. In polyester materials, the introduction of aromatic monomers can often improve the thermal stability and mechanical properties of polyesters, but has a negative impact on their sustainability and biodegradability; the introduction of linear aliphatic monomers can improve the toughness of polyesters while ensuring their biodegradability.
[0005] Based on this, it is necessary to provide a polyester preparation method that can not only highly value-utilize the organic solvents in waste lithium battery electrolyte, but also improve the thermal stability and mechanical properties of polyesters and ensure their biodegradability. Summary of the Invention
[0006] The purpose of the present invention is to provide a method for preparing bio-based carbonated diol polyester from waste electrolyte to solve the problems of high-value utilization of existing waste electrolyte and the performance of polyester materials.
[0007] The purpose of the present invention is achieved as follows:
[0008] A method for preparing bio-based carbonated diol polyester from waste electrolyte, the specific steps are as follows:
[0009] Step 1: Stir and mix according to the molar ratio of bio-based diol: waste electrolyte: catalyst C = 2 - 5:1 - 2:0.01. Add the above mixture into a high-gravity reactor, fill the high-gravity reactor with nitrogen for protection, heat the mixture in the high-gravity reactor to 70 - 100 °C, and the reaction time is 4 - 6 h;
[0010] Step 2: After no distillate is produced, evacuate the high-gravity reactor, reduce the pressure to 2 kPa and continue the reaction for 2 h; after the reaction is completed, add the product cooled to room temperature into dichloromethane for dissolution, perform vacuum rotary evaporation, and wash with ethyl acetate 3 times; put the washed product into an oven and dry it at 40 °C for 24 h to obtain bio-based dicarbonate diol ester after drying;
[0011] Step 3: Stir and mix according to the molar ratio of bio-based dicarbonate diol ester: dibasic acid: catalyst F = 1:1 - 2:0.02 - 0.05. Add the above mixture into a high-gravity reactor, fill the high-gravity reactor with nitrogen for protection, heat the mixture in the high-gravity reactor to 120 - 240 °C, and the reaction time is 3 h. After no distillate is produced, evacuate the reaction system, reduce the pressure to 2 kPa and continue the reaction for 4 - 6 h, then raise the reaction temperature to 240 °C until the stirrer power starts to rise and stop the reaction;
[0012] Step 4: After the reaction is completed, add the product cooled to room temperature into dichloromethane for dissolution, and precipitate the product with a large amount of methanol. After drying, obtain bio-based dicarbonate diol polyester.
[0013] In the above technical solution, the bio-based dicarbonate diol is an aliphatic diol with a cyclic structure extracted from bio-based materials, and the aliphatic diol is isosorbide (ISB).
[0014] In the above technical solution, the waste electrolyte is a low-boiling carbonate obtained by vacuum distillation in a short-path molecular evaporation reactor at 75 °C - 80 °C for 3 h, and the carbonate is a mixture of dimethyl carbonate (DMC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC), and the mixture recovery rate reaches 75 - 80%.
[0015] In the above technical solution, the catalyst C is an organic base, and the organic base is at least one of sodium methoxide (CH3ONa), sodium ethoxide (C2H5ONa), potassium carbonate methanolate (CH3OK), potassium ethoxide (C2H5OK), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), and 1,8-diazabicycloundec-7-ene (DBU).
[0016] In the above technical solution, the dibasic acid is at least one of succinic acid (SA), fumaric acid (FA), and 2,5-furandicarboxylic acid (FDCA).
[0017] In the above technical solution, the catalyst F is at least one of zinc acetate (Zn(OAc)2), tetrabutyl titanate (TBT), and triphenylphosphine (TPP).
[0018] Compared with the prior art, the present invention has the following beneficial effects:
[0019] The technical solution of the present invention uses the bio-based carbonated diol prepared from bio-based diols to replace the petroleum-based diol used in the traditional process to synthesize bio-based carbonated diol polyester on the basis of the original polyester synthesis process. Through data structure characterization, it is proved that the bio-based carbonated diol ester can improve the application performance of the polyester without damaging the mechanical properties and thermal properties. At the same time, the recovery efficiency of waste electrolyte is improved by passing through a short-path molecular evaporation reactor, providing a feasible solution for the high-value utilization of waste electrolyte. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.
[0021] Figure 1 It is the infrared spectrum diagram of bio-based carbonated diol polyester;
[0022] Figure 2 On the left is the molecular formula of bio-based carbonated diol polyester. Figure a is the 1H NMR spectrum of bio-based carbonated diol polyester; Figure b is the 13C NMR spectrum of bio-based carbonated diol polyester;
[0023] Figure 3 It is the GPC spectrum diagram of bio-based carbonated diol polyester;
[0024] Figure 4 It is the DSC spectrum diagram of bio-based carbonated diol polyester;
[0025] Figure 5 In the figure, Figure a is the TGA diagram of bio-based carbonated diol polyester; Figure b is the DTG diagram of bio-based carbonated diol polyester;
[0026] Figure 6 In the figure, Figure a is the stress-strain curve diagram of bio-based carbonated diol polyester; Figure b is the tensile strength and elongation at break diagram of bio-based carbonated diol polyester. DETAILED DESCRIPTION OF THE INVENTION
[0027] To enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.
[0028] The main method proposed by the present invention to solve the above problems is to use carbonate esters in the organic solvents of waste lithium battery electrolytes as raw materials to react with bio-based diols to prepare bio-based carbonic acid diol monomers, and then polymerize with dibasic acids to obtain bio-based carbonic acid diol polyesters. This method can improve the recovery rate and utilization rate of waste electrolyte products and improve the application performance of polyesters.
[0029] The present invention provides a method for preparing bio-based carbonic acid diol polyester based on waste electrolytes, and the specific steps are as follows:
[0030] Step 1: To ensure the biodegradability of the polyester, a bio-based diol is selected to react with the waste electrolyte. Stir and mix according to the molar ratio of bio-based diol: waste electrolyte: catalyst C = 2 - 5:1 - 2:0.01. Add the above mixture into a high-gravity reactor, fill the high-gravity reactor with nitrogen for protection, heat the mixture in the high-gravity reactor to 70 - 100 °C, and the reaction time is 4 - 6 h;
[0031] Step 2: After no distillate is produced, evacuate the high-gravity reactor, reduce the pressure to 2 kPa and continue the reaction for 2 h; after the reaction is completed, add the product cooled to room temperature to dichloromethane for dissolution, perform vacuum rotary evaporation, and wash with ethyl acetate 3 times; put the washed product into an oven and dry it at 40 °C for 24 h to obtain bio-based carbonic acid diol ester after drying;
[0032] Step 3: Stir and mix according to the molar ratio of bio-based carbonic acid diol ester: dibasic acid: catalyst F = 1:1 - 2:0.02 - 0.05. Add the above mixture into the high-gravity reactor, fill the high-gravity reactor with nitrogen for protection, heat the mixture in the high-gravity reactor to 120 - 240 °C, and the reaction time is 3 h. After no distillate is produced, evacuate the reaction system, reduce the pressure to 2 kPa and continue the reaction for 4 - 6 h, and then raise the reaction temperature to 240 °C until the power of the stirrer starts to rise and stop the reaction;
[0033] Step 4: After the reaction is completed, the product cooled to room temperature is added to dichloromethane for dissolution, and the product is precipitated by adding a large amount of methanol. After drying, a bio-based carbonic acid diol polyester is obtained.
[0034] As an alternative embodiment, the bio-based carbonic acid diol is an aliphatic diol with a cyclic structure extracted from a bio-based source, and the aliphatic diol is isosorbide (ISB).
[0035] As an alternative embodiment, the waste electrolyte is a low-boiling carbonate obtained by subjecting it to vacuum distillation at 75 °C - 80 °C for 3 h in a short-path molecular evaporation reactor, and the carbonate is a mixture of dimethyl carbonate (DMC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC). The mixture requires no further treatment, and the mixture recovery rate reaches 75 - 80%.
[0036] As an alternative embodiment, the catalyst C is an organic base, and the organic base is at least one of sodium methoxide (CH3ONa), sodium ethoxide (C2H5ONa), potassium carbonate methanolate (CH3OK), potassium ethoxide (C2H5OK), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), and 1,8-diazabicycloundec-7-ene (DBU).
[0037] As an alternative embodiment, the dicarboxylic acid is at least one of succinic acid (SA), fumaric acid (FA), and 2,5-furandicarboxylic acid (FDCA). The role of the dicarboxylic acid in the process of the present invention is to undergo a further condensation reaction with the bio-based carbonic acid diol ester to obtain a bio-based carbonic acid diol polyester.
[0038] As an alternative embodiment, the catalyst F is at least one of zinc acetate (Zn(OAc)2), tetrabutyl titanate (TBT), and triphenylphosphine (TPP).
[0039] The following provides a detailed introduction to the specific embodiments of the present invention:
[0040] Example 1
[0041] The waste electrolyte is a low-boiling carbonate obtained by subjecting it to vacuum distillation at 75 °C for 3 h in a short-path molecular evaporation reactor, and the carbonate is a mixture of dimethyl carbonate (DMC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC). The mixture recovery rate reaches 75%.
[0042] Example 2
[0043] The waste electrolyte is a low-boiling carbonate obtained by subjecting it to vacuum distillation at 80 °C for 3 h in a short-path molecular evaporation reactor, and the carbonate is a mixture of dimethyl carbonate (DMC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC), and the recovery rate of the mixture reaches 80%.
[0044] Example 3
[0045] The waste electrolyte is a low-boiling carbonate obtained by subjecting it to vacuum distillation at 77 °C for 3 h in a short-path molecular evaporation reactor, and the carbonate is a mixture of dimethyl carbonate (DMC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC), and the recovery rate of the mixture reaches 75.9%.
[0046] Example 4
[0047] The oven was adjusted to 110 °C, and all glassware used in the experiment was dried for more than 24 h; ISB, waste electrolyte B, and catalyst C were weighed in a molar ratio of 2:1:0.01 and added to a rotating packed bed reactor, nitrogen was introduced for protection, the oil bath was heated to 70 °C, and the reaction was carried out for 4 h. After no distillate was produced, the rotating packed bed reactor was evacuated, the pressure was reduced to 2 kPa and the reaction was continued for 2 h; after the reaction was completed, the product cooled to room temperature was added to dichloromethane for dissolution, and after vacuum rotary evaporation, the product was washed with ethyl acetate, and the dissolution-rotary evaporation-washing process was repeated 3 times; the washed product was placed in an oven and dried at 40 °C for 24 h. After drying, it was taken out and placed in a desiccator for standby, and the product was named isosorbide dicarbonate (BIC).
[0048] Example 5
[0049] The oven was adjusted to 110 °C, and all glassware used in the experiment was dried for more than 24 h; ISB, waste electrolyte B, and catalyst C were weighed in a molar ratio of 3:2:0.01 and added to a rotating packed bed reactor, nitrogen was introduced for protection, the oil bath was heated to 85 °C, and the reaction was carried out for 4 h. After no distillate was produced, the rotating packed bed reactor was evacuated, and the pressure was reduced to 2 kPa and the reaction was continued for 2 h; after the reaction was completed, the product cooled to room temperature was added to dichloromethane for dissolution, and after vacuum rotary evaporation, the product was washed with ethyl acetate, and the dissolution-rotary evaporation-washing process was repeated 3 times; the washed product was placed in an oven and dried at 40 °C for 24 h. After drying, it was taken out and placed in a desiccator for standby, and the product was named isosorbide dicarbonate (BIC).
[0050] Example 6
[0051] The oven was adjusted to 110 °C, and all glassware used in the experiment was dried for more than 24 h; ISB, waste electrolyte B, and catalyst C were weighed in a molar ratio of 5:2:0.01 and added to a rotating packed bed reactor. Nitrogen was introduced for protection, and the mixture was heated to 100 °C in an oil bath and reacted for 4 h. After no distillate was produced, the rotating packed bed reactor was evacuated, the pressure was reduced to 2 kPa, and the reaction was continued for 2 h; after the reaction was completed, the product cooled to room temperature was added to dichloromethane for dissolution. After vacuum rotary evaporation, the product was washed with ethyl acetate, and the dissolution-rotary evaporation-washing process was repeated 3 times; the washed product was placed in an oven and dried at 40 °C for 24 h. After drying, it was taken out and placed in a desiccator for standby. The product was named isosorbide dicarbonate (BIC).
[0052] Example 7
[0053] The oven was adjusted to 110 °C, and all glassware used in the experiment was dried for more than 24 h; BIC, FDCA, and catalyst F were weighed in a molar ratio of 1:1:0.02 and added to a rotating packed bed reactor. Nitrogen was introduced for protection, and the mixture was heated to 120 °C in an oil bath. After no distillate was produced, the rotating packed bed reactor was evacuated, the pressure was reduced to 2 kPa, and the reaction was continued for 4 - 6 h. Finally, the reaction temperature was raised to 240 °C until the stirrer power began to increase and the reaction was stopped; after the reaction was completed, the polymer cooled to room temperature was added to dichloromethane for dissolution, and the product was precipitated by adding a large amount of methanol. The dissolution-precipitation process was repeated 3 times; the washed polymer product was placed in an oven and dried at 40 °C for 24 h. After drying, it was taken out and placed in a desiccator for standby. The product was named poly(furandicarboxylic acid-isosorbide dicarbonate) (PFDI).
[0054] Example 8
[0055] The oven was adjusted to 110 °C, and all glassware used in the experiment was dried for more than 24 h; BIC, FA, and catalyst F were weighed in a molar ratio of 1:1.5:0.03 and added to a rotating packed bed reactor. Nitrogen was introduced for protection, and the mixture was heated to 150 °C in an oil bath. After no distillate was produced, the rotating packed bed reactor was evacuated, the pressure was reduced to 2 kPa, and the reaction was continued for 4 - 6 h. Finally, the reaction temperature was raised to 240 °C until the stirrer power began to increase and the reaction was stopped; after the reaction was completed, the polymer cooled to room temperature was added to dichloromethane for dissolution, and the product was precipitated by adding a large amount of methanol. The dissolution-precipitation process was repeated 3 times; the washed polymer product was placed in an oven and dried at 40 °C for 24 h. After drying, it was taken out and placed in a desiccator for standby. The product was named poly(fumaric acid-isosorbide dicarbonate) (PFI).
[0056] Example 9
[0057] The oven was adjusted to 110 °C, and all glassware used in the drying experiment was dried for more than 24 h; BIC, SA, and catalyst F were weighed in a molar ratio of 1:2:0.05 and added to the rotating packed bed reactor. Nitrogen was introduced for protection, and the mixture was heated to 180 °C in an oil bath. After no distillate was produced, the rotating packed bed reactor was evacuated, the pressure was reduced to 2 kPa, and the reaction continued for 4 - 6 h. Finally, the reaction temperature was increased to 240 °C until the power of the stirrer began to rise and the reaction was stopped; after the reaction was completed, the polymer cooled to room temperature was added to dichloromethane for dissolution, and the product was precipitated by adding a large amount of methanol. The dissolution - precipitation process was repeated 3 times; the washed polymer product was placed in an oven and dried at 40 °C for 24 h. After drying, it was taken out and placed in a desiccator for standby. The product was named poly(isosorbide dicarbonate succinate) (PSI).
[0058] It can be seen from Figure 1 that in the above - mentioned reaction product, the absorption peak at 3400 cm⁻¹ is the hydroxyl group of isosorbide, the absorption peak at 1730 cm⁻¹ is the stretching vibration peak of the ester group, and the absorption peak at 2910 cm⁻¹ is the symmetric stretching absorption peak of methylene in the chain. The above test results indicate that the product is the target product.
[0059] It can be seen from Figure 2 that the molecular formulas on the left from top to bottom are: poly(isosorbide dicarbonate furandicarboxylate) (PFDI), poly(isosorbide dicarbonate fumarate) (PFI), and poly(isosorbide dicarbonate succinate) (PSI); with the spatial structure and electronic effect of the dicarboxylic acid, in Figure a, the -OH in isosorbide gradually shifts to the low - frequency region from 1.36 ppm, 1.57 ppm, and 1.61 ppm; in Figure b, the characteristic peak of carbon atoms in isosorbide changes little, while the characteristic peak of carbon atoms in carboxylic acid gradually shifts to the high - frequency region.
[0060] It can be seen from Figure 3 that the number - average molecular weight of the above - mentioned reaction product is 1.8 - 3.8 kg / mol, indicating that the molecular weight distribution index of the product is 1.41 - 1.53.
[0061] It can be seen from Figure 4 that the Tg of the above - mentioned reaction product is 75.0 - 90.3 °C, and the Tm is 199.7 - 219.1 °C; this is because the presence of the BIC structure restricts the regular arrangement of polymer molecular chains and cannot present a regular crystal form under the action of temperature.
[0062] It can be seen from Figure 5 Figure a that at 600 °C, the residual mass percentage (Rw) of the above - mentioned reaction product is in the range of 12.1 - 18.5%, and it can be seen from Figure 5As can be seen from Figure b in the middle, the first inflection point of the curve is the initial decomposition temperature (Td,5%) of 226.2 - 300.6 °C, and the peak of the curve is the highest decomposition temperature (Td,max) of 316.5 - 358.6 °C; as the flexibility of the bio-based carbonate diol polyester chain segment increases, its Young's modulus decreases from 37.1 MPa to 32.7 MPa, and the breaking strength decreases from 48.1 MPa to 33.3 MPa.
[0063] It can be seen from Figure 6 Figure a in the middle that the stress-strain curves of the bio-based carbonate diol polyester all have obvious yield points, which is the same as that of typical thermoplastics; it can be seen from Figure 6 Figure b in the middle that the bio-based carbonate diol polyester also has good elastic behavior and high tensile strength.
[0064] The above are only some preferred embodiments of the present invention. The present invention is not limited to the content of the embodiments. For those skilled in the art, various changes and modifications can be made within the scope of the concept of the technical solution of the present invention. Any changes and modifications made are within the protection scope of the present invention.
[0065] Combined with the data in the figure, the performance of three common bio-based homopolyesters on the market is compared as shown in Table 1:
[0066] Table 1 Performance comparison table of bio-based carbonate diol polyester prepared from waste electrolyte and commercially available bio-based polyesters
[0067]
[0068] As can be seen from Table 1, the Tg (75 - 90 °C) and Tm (199 - 219 °C) of the bio - based carbonated diol polyester are significantly higher than those of PLA, PHA, and PBS. This is because the cyclic structure of isosorbide (ISB) restricts the movement of molecular chains, and the carbonate group further enhances the intermolecular force, enabling the material to remain stable at high temperatures; the Td,5% of the BIC - based polyester is up to 300.6 °C, far exceeding that of PLA (220 °C) and PHA (220 °C), making it suitable for components around automobile engines or high - temperature processing processes. Moreover, different material properties can be achieved by selecting dibasic acids (such as enhancing the rigidity to 48.1 MPa with FDCA and enhancing flexibility with SA), which can be adapted to different application scenarios (such as high - strength films or flexible packaging, etc.); the yield point of the stress - strain curve of the bio - based carbonated diol polyester indicates that the material has an elastic behavior similar to thermoplastics, overcoming the brittle defect of PLA; traditional PLA relies on corn starch, while the present invention solves the problem of electronic waste pollution and reduces raw material costs by recycling carbonates (such as DMC, DEC) in lithium - ion battery electrolytes; the introduction of aliphatic dibasic acids (such as SA, FA) enhances the hydrolysis sensitivity of the molecular chain. Combining with the bio - based characteristics of ISB, the material may degrade in the natural environment without harsh composting conditions.
[0069] In summary, as a comonomer, the bio - based carbonated diol ester can introduce a carbonate group into the polyester without damaging the mechanical and thermal properties, thereby achieving the purpose of optimizing the polyester properties.
[0070] The present invention relates to a method for preparing bio - based carbonated diol polyester from waste electrolytes; the present invention solves the problems of the unsustainability of traditional petroleum - based polyesters and the balance of the thermodynamic and mechanical properties of polyesters, and can be used for the industrial production of new bio - based polyesters.
[0071] The above - mentioned are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claimed rights.
Claims
1. A method for preparing bio-based carbonated diol polyester from waste electrolyte, characterized in that, The specific steps are as follows: Step 1: Stir and mix according to the molar ratio of bio-based diol: waste electrolyte: catalyst C = 2 - 5:1 - 2:0.
01. Add the above mixture into a high-gravity reactor, fill the high-gravity reactor with nitrogen for protection, heat the mixture in the high-gravity reactor to 70 - 100 °C, and the reaction time is 4 - 6 h; Step 2: After no distillate is produced, evacuate the high-gravity reactor, reduce the pressure to 2 kPa and continue the reaction for 2 h; after the reaction is completed, add the product cooled to room temperature to dichloromethane for dissolution, perform vacuum rotary evaporation, and wash with ethyl acetate 3 times; put the washed product into an oven and dry it at 40 °C for 24 h to obtain bio-based carbonic acid diol ester after drying; Step 3: Stir and mix according to the molar ratio of bio-based carbonic acid diol ester: dicarboxylic acid: catalyst F = 1:1 - 2:0.02 - 0.
05. Add the above mixture into a high-gravity reactor, fill the high-gravity reactor with nitrogen for protection, heat the mixture in the high-gravity reactor to 120 - 240 °C, and the reaction time is 3 h. After no distillate is produced, evacuate the reaction system, reduce the pressure to 2 kPa and continue the reaction for 4 - 6 h, and then raise the reaction temperature to 240 °C until the stirrer power starts to rise and stop the reaction; Step 4: After the reaction is completed, add the product cooled to room temperature to dichloromethane for dissolution, and precipitate the product with a large amount of methanol. After drying, obtain bio-based carbonic acid diol polyester.
2. The method for preparing bio-based carbonated diol polyester from waste electrolyte according to claim 1, characterized in that, The bio-based carbonic acid diol is an aliphatic diol with a cyclic structure extracted from bio-based materials, and the aliphatic diol is isosorbide (ISB).
3. The method for preparing bio-based carbonated diol polyester from waste electrolyte according to claim 1, wherein The waste electrolyte is a low-boiling carbonate obtained by vacuum distillation in a short-path molecular evaporation reactor at 75 °C - 80 °C for 3 h, and the carbonate is a mixture of dimethyl carbonate (DMC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC), and the mixture recovery rate reaches 75 - 80%.
4. The method for preparing bio-based carbonated diol polyester from waste electrolyte according to claim 1, characterized in that, The catalyst C is an organic base, and the organic base is at least one of sodium methoxide (CH3ONa), sodium ethoxide (C2H5ONa), potassium carbonate methanolate (CH3OK), potassium ethoxide (C2H5OK), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), and 1,8-diazabicycloundec-7-ene (DBU).
5. The method for preparing bio-based carbonated diol polyester from waste electrolyte according to claim 1, wherein The dicarboxylic acid is at least one of succinic acid (SA), fumaric acid (FA), and 2,5-furandicarboxylic acid (FDCA).
6. The method for preparing bio-based carbonated diol polyester from waste electrolyte according to claim 1, characterized in that, The catalyst F is at least one of zinc acetate (Zn(OAc)2), tetrabutyl titanate (TBT), and triphenylphosphine (TPP).
7. The method for preparing bio-based carbonated diol polyester from waste electrolyte according to claim 1, characterized in that, The bio-based carbonic acid diol polyester is at least one of poly(2,5-furandicarboxylic acid-isosorbide carbonate) (PFDI), poly(fumaric acid-isosorbide carbonate) (PFI), and poly(succinic acid-isosorbide carbonate) (PSI).