Nucleating agent for purifying isosorbide and preparation method thereof

Abstract

The invention belongs to the technical field of high polymer materials, and relates to a nucleating agent for purifying isosorbide and a preparation method thereof. The structural formula of the nucleating agent is shown in the specification, wherein X is Na, K or Li; or, the structural formula of the nucleating agent is shown in the specification, and in the formula, Z is Mg or Ca. The preparation method comprises the following steps: mixing refined isosorbide with strong base or metal, and reacting to obtain the nucleating agent for purifying isosorbide. The preparation method is simple, and the prepared nucleating agent can be used for purifying isosorbide to obtain high-purity crystals.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology and relates to a nucleating agent for isosorbide purification and its preparation method, specifically a divisional application with application number 202511761860.1, application date November 27, 2025, entitled "A method for isosorbide purification based on green solvent and its application in polycarbonate preparation". Background Technology

[0002] Bio-based isosorbide, a platform compound with a rigid bicyclic structure, is a renewable polymer monomer derived from non-grain biomass such as lignocellulose. Its unique molecular configuration makes it an ideal choice for constructing high-glass transition temperature, high-performance polymer materials. However, the synthesis of isosorbide is prone to leaving isomers such as isomannitol and isoadulol, as well as impurities such as dehydration products, degradation byproducts, and residual catalysts. If the purity cannot be increased to above 99.5%, it will not only limit the polymer molecular weight and make it prone to yellowing, but also keep its penetration rate in the field of engineering plastics below 12% for a long time, making it difficult to shake the dominant position of petroleum-based monomers. Therefore, efficient purification technology is a key bottleneck for the large-scale application of isosorbide.

[0003] However, existing methods for isosorbide purification have many insurmountable drawbacks.

[0004] For example, patent CN107141301B integrates the preparation and purification of isosorbide into one device. After decolorization, deionization, concentration, room temperature aqueous phase crystallization and drying, the purity of the obtained product is only over 98%, which is far from meeting the preparation standards of high-performance polymers.

[0005] Patent application CN116444537A uses hydrophobic activated carbon for refining. However, the activation of activated carbon requires multiple steps such as impregnation, washing, and drying. Furthermore, it requires the use of inorganic acids such as hydrochloric acid and nitric acid, as well as monohydric alcohols such as methanol, as activation solutions. This process easily generates acidic wastewater and organic waste liquid, causing secondary pollution and posing serious environmental hazards.

[0006] Although the extraction-crystallization method proposed in patent application CN118546152A can achieve high purity and recovery rate, it uses a large amount of organic solvents such as ethyl acetate, which easily generates high-concentration waste liquid and poses a potential environmental pollution risk.

[0007] Patent application CN114276363A claims that the residual 4-9 wt% of diol does not affect the polymerization reaction, but for some polycarbonate systems that require high quality, such residual impurities will seriously damage the material properties and restrict the application of purified products in the field of high-end polymers.

[0008] In the preparation of downstream polycarbonate polymers of isosorbide, existing purification methods still face additional technical obstacles: purified isosorbide crystals often have residual solvent or impurities, requiring an additional solvent removal step, which not only increases process complexity and energy consumption, but may also affect polymerization efficiency due to incomplete removal; at the same time, traditional polymerization processes usually require the addition of additional catalysts, further increasing production costs and process control difficulties, thus restricting the large-scale production of isosorbide-based polycarbonates. Summary of the Invention

[0009] The purpose of this invention is to solve the problems existing in the prior art and to provide a nucleating agent for isosorbide purification and its preparation method.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] A method for isosorbide purification based on a green solvent involves performing at least one dissolution-crystallization operation. The first dissolution-crystallization operation is as follows: crude isosorbide (i.e., unpurified isosorbide) is first dissolved in carbonate to obtain a solution; then a nucleating agent is added to the solution, and the solution is cooled and crystallized to precipitate isosorbide crystals; finally, the isosorbide crystals are separated. The difference between the nth dissolution-crystallization operation and the first dissolution-crystallization operation is that the crude isosorbide is replaced with the isosorbide crystals obtained in the previous dissolution-crystallization operation, where n>1.

[0012] The structural formula of the nucleating agent is as follows:

[0013]

[0014] In the formula, X is Na, K, or Li;

[0015] Alternatively, the structural formula of the nucleating agent is as follows:

[0016]

[0017] In the formula, Z represents Mg or Ca.

[0018] Isosorbide molecules contain multiple hydroxyl groups and ether bonds, making them highly polar organic compounds. According to the principle of "like dissolves like," the solvent should also be highly polar to dissolve isosorbide. Carbonates contain highly polar carbonyl groups (C=O) and polar CO bonds, which can dissolve isosorbide through dipole-dipole interactions.

[0019] If no nucleating agent is added, isosorbide will precipitate oil and will not form isosorbide crystals because isosorbide has high solubility in carbonates at low temperatures.

[0020] To prevent other isomers and byproducts from crystallizing simultaneously with isosorbide, the present invention features a specially designed nucleating agent. This nucleating agent, due to its structural similarity to isosorbide, exhibits a specific affinity for isosorbide and can preferentially induce isosorbide molecules to nucleate. Impurities in isosorbide mainly include isosorbide isomers (isomannitol, isoadurel), residual acidic catalysts, intermediate byproducts, etc. Although these impurities are all well soluble in carbonates, they cannot preferentially nucleate and therefore cannot crystallize simultaneously with isosorbide.

[0021] As a preferred technical solution:

[0022] The method for purifying isosorbide using a green solvent, as described above, involves the preparation of a nucleating agent as follows: Isosorbide (i.e., purified isosorbide) is mixed with a strong base at a molar ratio of 3-4:2, and reacted at 25-160℃ for 3-10 hours to obtain the nucleating agent; the strong base is NaOH or KOH.

[0023] Alternatively, the nucleating agent can be prepared by mixing isosorbide in a molar ratio of 1:1-2 with a metal and reacting at 25-160℃ for 3-10 hours to obtain the nucleating agent; the metal can be Li, Mg, or Ca; taking Li and Mg as examples, the reaction equation is as follows:

[0024]

[0025] The isosorbide purification method based on green solvents described above has a crude isosorbide to carbonate mass ratio of 1:1 to 1:3, and the nucleating agent mass is 0.05% to 0.1% of the crude isosorbide mass.

[0026] The isosorbide purification method based on green solvents described above involves a dissolution temperature of 40-60℃ and a dissolution time of 30-60 min.

[0027] The isosorbide purification method based on green solvents described above has a cooling crystallization temperature of 0-25℃ and a cooling crystallization time of 60-120 min.

[0028] In the isosorbide purification method based on green solvents as described above, the carbonate is dimethyl carbonate, or diethyl carbonate, or dipropyl carbonate, or methyl ethyl carbonate, or a mixture of dimethyl carbonate and diethyl carbonate.

[0029] As described above, in the isosorbide purification method based on a green solvent, the dissolution-crystallization operation is performed 1-5 times. No impurities were found in the isosorbide crystals by GC-MS detection (possibly because the nucleating agent content was too low to be detected by GC-MS).

[0030] The present invention also provides a method for preparing polycarbonate polymers, wherein isosorbide crystals are first obtained by isosorbide purification using a green solvent-based method as described in any of the preceding claims, and then the isosorbide crystals are directly mixed with carbonate and subjected to transesterification and polycondensation reactions in sequence to obtain polycarbonate polymers.

[0031] The isosorbide crystals obtained in this invention carry trace amounts of carbonate, which do not need to be removed and can be directly used for polymerization to prepare polycarbonate polymers. The nucleating agent carried can play a synergistic catalytic role in the polymerization process because the nucleating agent can dissociate alkali metal ions during polycarbonate synthesis. Taking Li+ as an example, the reaction mechanism is as follows:

[0032]

[0033] Alkali metal ions have low charge density and weak coordination ability, and they can form loose ion pairs with oxonions, which makes the oxonions (nucleophiles) sufficiently reactive to attack carbonyl carbons.

[0034] As a preferred technical solution:

[0035] The method for preparing a polycarbonate polymer compound as described above, wherein the carbonate is one or more of dimethyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl carbonate, dipentyl carbonate, diheptyl carbonate, diphenyl carbonate, dibenzyl carbonate, and benzylphenyl carbonate.

[0036] The method for preparing a polycarbonate polymer compound as described above involves a molar ratio of isosorbide crystals to carbonate of 1:1-1.06; an ester exchange reaction at a temperature of 110-150℃ for 2-4 hours under nitrogen or inert gas protection; a polycondensation reaction at a temperature of 210-250℃ for 20-60 minutes under a pressure of 120-150 Pa; and isosorbide polycarbonate with a glass transition temperature of 170-175℃, an intrinsic viscosity of 50.04-55.02 mL / g, and a viscosity-average molecular weight of 28578-32085 g / mol.

[0037] A method for preparing a copolycarbonate polymer involves first obtaining isosorbide crystals using an isosorbide purification method based on a green solvent as described in any of the preceding methods. Then, the comonomer and isosorbide crystals are directly mixed with carbonate and subjected to transesterification and polycondensation reactions in sequence to obtain the copolycarbonate polymer. The comonomer is selected from diols that do not contain isosorbide, specifically aliphatic diols, alicyclic diols, or aromatic diols.

[0038] As a preferred technical solution:

[0039] The preparation method of the copolycarbonate polymer compound as described above, wherein the carbonate is one or more of dimethyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl carbonate, dipentyl carbonate, diheptyl carbonate, diphenyl carbonate, dibenzyl carbonate, and benzylphenyl carbonate.

[0040] The preparation method of the copolycarbonate polymer compound described above involves a ratio of the total molar amount of comonomer and isosorbide crystals to the molar amount of carbonate of 1:1-1.06; a molar ratio of comonomer to isosorbide crystals of 3:7-7:3; an ester exchange reaction at 110-150℃ for 2-4 h under nitrogen or inert gas protection; a polycondensation reaction at 210-250℃ for 60-120 min under 120-150 Pa pressure; and a copolymer compound with an intrinsic viscosity of 41.72-50.69 mL / g and a viscosity-average molecular weight of 22898-29032 g / mol.

[0041] Beneficial effects:

[0042] (1) This invention avoids the oil precipitation phenomenon of isosorbide by adding a nucleating agent with a specific structure to a carbonate green solvent for dissolution-crystallization, preferentially induces isosorbide molecules to nucleate and crystallize, effectively separates impurities such as isomers, dehydration products, and degradation by-products, and obtains high-purity isosorbide crystals that meet the requirements for use in polymerization.

[0043] (2) The present invention uses green solvent carbonate, and the purification process can achieve efficient purification by simply repeating the dissolution-crystallization operation. There is no need for complicated decolorization, extraction or special adsorption material activation steps. The process is simple and environmentally friendly, avoiding secondary pollution such as acidic wastewater and high-concentration organic waste liquid.

[0044] (3) The trace amounts of carbonate carried by the purified isosorbide crystals of the present invention do not need to be removed. They can be directly mixed with carbonates to carry out transesterification and polycondensation reactions to prepare polycarbonate polymers. The nucleating agent carried can dissociate alkali metal ions during polymerization to play a synergistic catalytic role, eliminating the need for additional solvent removal and catalyst addition steps, simplifying the process, and reducing energy consumption and production costs. Attached Figure Description

[0045] Figure 1 This is a comparison chart of GC-MS detection of the products of Example 3 and Comparative Example 1 in step (3). Detailed Implementation

[0046] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0047] To ensure that the performance of the substances used in each embodiment and comparative example is fully disclosed, the manufacturer information of the substances is specified in this invention; in addition, products from other manufacturers that conform to the limitations of this invention are also applicable.

[0048] The following are the test methods for the relevant performance indicators in each embodiment:

[0049] Glass transition temperature: Determined by differential scanning calorimetry (DSC) on a TA DSC Q20 instrument. For each test, 5-10 mg of sample was taken and heated and cooled in a nitrogen atmosphere (flow rate 50 mL / min) at a heating rate of 10 °C / min in the range of -50 °C to 230 °C. The glass transition temperature (Tg) was determined based on the data from the second heating scan.

[0050] Intrinsic viscosity and viscosity-average molecular weight: measured using a Ubbelohde capillary viscometer at 25±0.1℃; 0.25g of sample was dissolved in 25mL of solvent (CHCl3) to obtain a sample solution, and the outflow time of the solvent and the outflow time of the sample solution were measured at the same temperature. The intrinsic viscosity and viscosity-average molecular weight were calculated by measuring the relative viscosity and specific viscosity of the sample solution.

[0051] η r =t / t0;

[0052] η sp =η r -1;

[0053]

[0054] In the formula, ηr is the relative viscosity of the sample solution; t0 is the solvent effluent time (s); t is the sample solution effluent time (s); η sp [η] represents the specific viscosity; [η] represents the intrinsic viscosity (mL / g); C represents the concentration of the sample solution (g / mL); K and α represent the Mark-Houwink equation constants for the sample-chloroform system at 25℃ (K = 0.0111 mL / g, α = 0.82 in this invention); Mη represents the viscosity-average molecular weight (g / mol).

[0055] In the following embodiments, the column operating parameters for GC-MS detection were as follows: injector temperature 300℃, split injection mode, injection time 1 min; carrier gas was high-purity helium (≥99.999%), control mode was pressure, carrier gas pressure was 49.5 kPa, and total flow rate was 104 mL·min. -1 Column flow rate 1.0 mL / min -1 Linear speed 36.1 cm·s -1 3 mL / min purging flow rate -1 The split ratio was 100:1; the temperature program was as follows: initial temperature 40℃ held for 3 min, then increased to 300℃ at 12℃ / min and held for 3 min; the injection volume was 0.5 μL, and the run time was 27.67 min.

[0056] The mass spectrometry operating parameters were as follows: EI ion source, threshold 0, ion source temperature 200℃, interface temperature 300℃, solvent delay time 1min, detector voltage 0.9kV (absolute value), microscan width 0u, full scan monitoring mode, and acquisition interval 0.3s.

[0057] Example 1

[0058] A method for preparing a polycarbonate polymer compound, comprising the following specific steps:

[0059] (1) Preparation of materials;

[0060] Isosorbide dinitrate: Manufacturer: Roquette (China) Fine Chemicals Co., Ltd.;

[0061] Strong base: KOH;

[0062] Crude isosorbide: Manufacturer is Shanghai Titan Co., Ltd., product number is 013709791;

[0063] Carbonate a: dipropyl carbonate;

[0064] Carbonate b: dibutyl carbonate;

[0065] (2) Preparation of nucleating agents;

[0066] The nucleating agent is obtained by mixing isosorbide in a molar ratio of 3:2 with a strong base and reacting at 85°C for 7 hours.

[0067] (3) Perform one dissolution-crystallization operation;

[0068] The dissolution-crystallization process is as follows: first, crude isosorbide is dissolved in carbonate a to obtain a solution, then a nucleating agent is added to the solution and cooled to crystallize isosorbide crystals, and then the isosorbide crystals are separated.

[0069] The dissolution temperature was 40℃, the dissolution time was 30 min, the cooling crystallization temperature was 0℃, and the cooling crystallization time was 60 min; the mass ratio of crude isosorbide to carbonate a was 1:1, and the mass of the nucleating agent was 0.05% of the mass of crude isosorbide.

[0070] The isosorbide crystals obtained by the dissolution-crystallization operation were analyzed by GC-MS, and no impurities were found; the yield of isosorbide crystals was 90%.

[0071] (4) Preparation of polycarbonate polymers;

[0072] Isosorbide crystals were directly mixed with carbonate b and then subjected to transesterification and polycondensation reactions to obtain polycarbonate polymers.

[0073] The molar ratio of isosorbide crystals to carbonate b is 1:1; the transesterification reaction is carried out at 110℃ for 4 hours under nitrogen or inert gas protection; the polycondensation reaction is carried out at 210℃ for 60 minutes under 120 Pa pressure.

[0074] The final polycarbonate polymer compound had a glass transition temperature of 170℃, an intrinsic viscosity of 50.04 mL / g, and a viscosity-average molecular weight of 28578 g / mol.

[0075] Example 2

[0076] A method for preparing a polycarbonate polymer compound, comprising the following specific steps:

[0077] (1) Preparation of materials;

[0078] Isosorbide dinitrate: Manufacturer: Roquette (China) Fine Chemicals Co., Ltd.;

[0079] Strong base: NaOH;

[0080] Crude isosorbide: Manufacturer is Shanghai Myriel Biochemical Technology Co., Ltd., product number is M04808;

[0081] Carbonate a: Diethyl carbonate;

[0082] Carbonate b: Dipentyl carbonate;

[0083] (2) Preparation of nucleating agents;

[0084] The nucleating agent is obtained by mixing isosorbide in a molar ratio of 4:2 with a strong base and reacting at 90°C for 6 hours.

[0085] (3) Perform two dissolution-crystallization operations;

[0086] The first dissolution-crystallization operation is as follows: crude isosorbide is first dissolved in carbonate a to obtain a solution, then a nucleating agent is added to the solution and cooled to crystallize isosorbide crystals, and then the isosorbide crystals are separated; the second dissolution-crystallization operation differs from the first dissolution-crystallization operation in that crude isosorbide is replaced with the isosorbide crystals obtained in the first dissolution-crystallization operation.

[0087] The dissolution temperature was 45℃, the dissolution time was 40 min, the cooling crystallization temperature was 5℃, and the cooling crystallization time was 75 min; the mass ratio of crude isosorbide to carbonate a was 1:1.5, and the mass of the nucleating agent was 0.06% of the mass of crude isosorbide.

[0088] The isosorbide crystals obtained from the final dissolution-crystallization operation were analyzed by GC-MS, and no impurities were found; the yield of isosorbide crystals was 85%.

[0089] (4) Preparation of polycarbonate polymers;

[0090] The isosorbide crystals obtained from the last dissolution-crystallization operation in step (3) are directly mixed with carbonate b and then subjected to transesterification and polycondensation reactions in sequence to obtain polycarbonate polymers.

[0091] The molar ratio of isosorbide crystals to carbonate b is 1:1.02; the transesterification reaction is carried out at 120℃ for 3.5 h under nitrogen or inert gas protection; the polycondensation reaction is carried out at 220℃ for 50 min under 130 Pa pressure.

[0092] The final polycarbonate polymer compound had a glass transition temperature of 172℃, an intrinsic viscosity of 51.67 mL / g, and a viscosity-average molecular weight of 29720 g / mol.

[0093] Example 3

[0094] A method for preparing a polycarbonate polymer compound, comprising the following specific steps:

[0095] (1) Preparation of materials;

[0096] Isosorbide dinitrate: Manufacturer: Roquette (China) Fine Chemicals Co., Ltd.;

[0097] Metal: Li;

[0098] Crude isosorbide: Manufacturer is Shanghai Myriel Biochemical Technology Co., Ltd., product number is M35263;

[0099] Carbonate a: dimethyl carbonate;

[0100] Carbonate b: diphenyl carbonate;

[0101] (2) Preparation of nucleating agents;

[0102] The nucleating agent is obtained by mixing isosorbide in a molar ratio of 1:2 with a metal and reacting at 25°C for 3 hours.

[0103] (3) Perform three dissolution-crystallization operations;

[0104] The first dissolution-crystallization operation is as follows: crude isosorbide is first dissolved in carbonate a to obtain a solution, then a nucleating agent is added to the solution and cooled to crystallize isosorbide crystals, and then the isosorbide crystals are separated; the difference between the second and third dissolution-crystallization operations and the first dissolution-crystallization operation is that the crude isosorbide is replaced with the isosorbide crystals obtained in the previous dissolution-crystallization operation;

[0105] The dissolution temperature was 50℃, the dissolution time was 50 min, the cooling crystallization temperature was 10℃, and the cooling crystallization time was 90 min; the mass ratio of crude isosorbide to carbonate a was 1:2, and the mass of the nucleating agent was 0.07% of the mass of crude isosorbide.

[0106] The isosorbide crystals obtained from the final dissolution-crystallization operation were analyzed by GC-MS, and no impurities were found (e.g., Figure 1 (As shown); the yield of isosorbide crystals was 80%;

[0107] (4) Preparation of polycarbonate polymers;

[0108] The isosorbide crystals obtained from the last dissolution-crystallization operation in step (3) are directly mixed with carbonate b and then subjected to transesterification and polycondensation reactions in sequence to obtain polycarbonate polymers.

[0109] The molar ratio of isosorbide crystals to carbonate b is 1:1.03; the transesterification reaction is carried out at 130℃ for 3 hours under nitrogen or inert gas protection; the polycondensation reaction is carried out at 230℃ for 40 minutes under 135 Pa pressure.

[0110] The final polycarbonate polymer compound had a glass transition temperature of 175℃, an intrinsic viscosity of 55.02 mL / g, and a viscosity-average molecular weight of 32085 g / mol.

[0111] Comparative Example 1

[0112] A method for preparing a polycarbonate polymer compound, which differs from Example 3 in that: in step (3), no nucleating agent is added;

[0113] Because isosorbide has high solubility in carbonates at low temperatures, oil precipitation occurred. After step (3), isosorbide crystals could not be formed, and the oil precipitation product from step (3) was detected by GC-MS, revealing impurities (such as...). Figure 1 (As shown).

[0114] The final polycarbonate polymer compound had a glass transition temperature of 166℃, an intrinsic viscosity of 44.59 mL / g, and a viscosity-average molecular weight of 24830 g / mol.

[0115] Compared with Comparative Example 1 and Example 3, the glass transition temperature, intrinsic viscosity and viscosity-average molecular weight of polycarbonate polymers were significantly reduced. This is because the crystallization process of isosorbide was out of control when there was no nucleating agent, and the impurities could not be effectively separated. The residual impurities inhibited the growth of molecular chains and triggered side reactions during the polymerization stage, resulting in a decrease in viscosity-average molecular weight, intrinsic viscosity and glass transition temperature.

[0116] Comparative Example 2

[0117] A method for preparing a polycarbonate polymer compound, which differs from Example 3 in that the nucleating agent is replaced with dibenzyl sorbitol;

[0118] Due to the significant differences in molecular structure between dibenzylidene sorbitol and isosorbide, dibenzylidene sorbitol lacks specific affinity and cannot preferentially induce isosorbide molecules to oriented and nucleate. At the same time, its interaction with isosorbide in carbonates is weak, making it difficult to effectively reduce the supersaturation of isosorbide and promote crystal growth, resulting in oil precipitation in step (3) and the inability to form complete isosorbide crystals. GC-MS detection results show that the product contains impurities. The core reason is that dibenzylidene sorbitol cannot achieve selective nucleation of isosorbide, and the impurities remain due to the failure to effectively separate them. Furthermore, the insufficient crystallization process further exacerbates the impurity entrainment.

[0119] The final polycarbonate polymer compound had a glass transition temperature of 167℃, an intrinsic viscosity of 44.94 mL / g, and a viscosity-average molecular weight of 25069 g / mol.

[0120] Compared with Comparative Example 2 and Example 3, the glass transition temperature, intrinsic viscosity and viscosity-average molecular weight of polycarbonate polymers were significantly reduced. This is because the selective nucleation ability of dibenzyl sorbitol was lost, resulting in insufficient purity and incomplete crystallization of isosorbitol, which in turn affected the polymerization efficiency and the final properties of the polymer.

[0121] Comparative Example 3

[0122] A method for preparing a polycarbonate polymer compound, which differs from Example 3 in that the nucleating agent is replaced with talc (manufacturer: Shanghai Titan Technology Co., Ltd., item number: 01025373);

[0123] Talc is a common inorganic nucleating agent, but because its molecular structure is very different from that of isosorbide, it cannot specifically recognize isosorbide. In step (3), after cooling and crystallization, some oil precipitation occurred, and the isosorbide crystals were not fully formed. GC-MS detection showed that the product contained impurities. The reason for this phenomenon is that the nucleation effect of talc is non-selective, which may induce the nucleation of impurities at the same time, resulting in a decrease in the purity of isosorbide. In addition, the surface properties of its particles do not match those of isosorbide, which reduces the crystallization efficiency.

[0124] The final polycarbonate polymer compound had a glass transition temperature of 167℃, an intrinsic viscosity of 45.22 mL / g, and a viscosity-average molecular weight of 25257 g / mol.

[0125] Compared with Comparative Example 3 and Example 3, the glass transition temperature, intrinsic viscosity and viscosity-average molecular weight of polycarbonate polymers were significantly reduced. This is because the non-selective nucleation of talc leads to a decrease in the purity of isosorbide and incomplete crystallization. Residual impurities interfere with the reaction during polymerization, ultimately reducing the molecular weight and overall performance of the polymer.

[0126] Comparative Example 4

[0127] A method for preparing a polycarbonate polymer compound, which differs from Example 3 in that the nucleating agent is replaced with sodium benzoate;

[0128] Sodium benzoate is an organic salt nucleating agent, but because its molecular structure is not similar to that of isosorbide, it cannot achieve specific nucleation. In step (3), some oil precipitation occurred, and the isosorbide crystals were not fully precipitated. GC-MS detected obvious impurity peaks. The reason for this phenomenon is that sodium benzoate has a weak affinity for isosorbide in carbonates and cannot preferentially induce isosorbide molecules to arrange for nucleation. Instead, it may interfere with the crystallization process and leave impurities in the crystals.

[0129] The final polycarbonate polymer compound had a glass transition temperature of 169℃, an intrinsic viscosity of 48.64 mL / g, and a viscosity-average molecular weight of 27607 g / mol.

[0130] Compared with Comparative Example 4 and Example 3, the glass transition temperature, intrinsic viscosity and viscosity-average molecular weight of polycarbonate polymers were significantly reduced. This is because sodium benzoate lacks specific nucleation ability, resulting in incomplete crystallization of isosorbide and impurity entrainment, which in turn affects the smooth progress of subsequent polymerization reactions.

[0131] Example 4

[0132] A method for preparing a polycarbonate polymer compound, comprising the following specific steps:

[0133] (1) Preparation of materials;

[0134] Isosorbide dinitrate: Manufacturer: Roquette (China) Fine Chemicals Co., Ltd.;

[0135] Metal: Mg;

[0136] Crude isosorbide: Manufacturer is Sinopharm Chemical Reagent Co., Ltd., product number is 80075363;

[0137] Carbonate a: Methyl ethyl carbonate;

[0138] Carbonate b: Dibenzyl carbonate;

[0139] (2) Preparation of nucleating agents;

[0140] The nucleating agent is obtained by mixing isosorbide in a molar ratio of 1:1 with a metal and reacting at 160°C for 8 hours.

[0141] (3) Perform 4 dissolution-crystallization operations;

[0142] The first dissolution-crystallization operation is as follows: crude isosorbide is first dissolved in carbonate a to obtain a solution, then a nucleating agent is added to the solution and cooled to crystallize isosorbide crystals, and then the isosorbide crystals are separated; the difference between the second to fourth dissolution-crystallization operations and the first dissolution-crystallization operation is that the crude isosorbide is replaced with the isosorbide crystals obtained in the previous dissolution-crystallization operation;

[0143] The dissolution temperature was 55℃, the dissolution time was 55 min, the cooling crystallization temperature was 15℃, and the cooling crystallization time was 105 min; the mass ratio of crude isosorbide to carbonate a was 1:2.5, and the mass of the nucleating agent was 0.08% of the mass of crude isosorbide.

[0144] The isosorbide crystals obtained from the final dissolution-crystallization operation were analyzed by GC-MS, and no impurities were found; the yield of isosorbide crystals was 75%.

[0145] (4) Preparation of polycarbonate polymers;

[0146] The isosorbide crystals obtained from the last dissolution-crystallization operation in step (3) are directly mixed with carbonate b and then subjected to transesterification and polycondensation reactions in sequence to obtain polycarbonate polymers.

[0147] The molar ratio of isosorbide crystals to carbonate b is 1:1.04; the transesterification reaction is carried out at a temperature of 140℃ for 2.5 h under nitrogen or inert gas protection; the polycondensation reaction is carried out at a temperature of 240℃ for 30 min under a pressure of 140 Pa.

[0148] The final polycarbonate polymer compound had a glass transition temperature of 173℃, an intrinsic viscosity of 54.96 mL / g, and a viscosity-average molecular weight of 32041 g / mol.

[0149] Example 5

[0150] A method for preparing a polycarbonate polymer compound, comprising the following specific steps:

[0151] (1) Preparation of materials;

[0152] Isosorbide dinitrate: Manufacturer: Roquette (China) Fine Chemicals Co., Ltd.;

[0153] Metal: Ca;

[0154] Crude isosorbide: Manufacturer is Shanghai Maclean Biochemical Technology Co., Ltd., product number is C805218;

[0155] Carbonate a: a mixture of dimethyl carbonate and diethyl carbonate in a volume ratio of 3:1;

[0156] Carbonate b: Benzylphenyl carbonate;

[0157] (2) Preparation of nucleating agents;

[0158] The nucleating agent is obtained by mixing isosorbide in a molar ratio of 1:1 with a metal and reacting at 160°C for 10 hours.

[0159] (3) Perform 5 dissolution-crystallization operations;

[0160] The first dissolution-crystallization operation is as follows: crude isosorbide is first dissolved in carbonate a to obtain a solution, then a nucleating agent is added to the solution and cooled to crystallize isosorbide crystals, and then the isosorbide crystals are separated; the difference between the second to fifth dissolution-crystallization operations and the first dissolution-crystallization operation is that the crude isosorbide is replaced with the isosorbide crystals obtained in the previous dissolution-crystallization operation;

[0161] The dissolution temperature was 60℃, the dissolution time was 60 min, the cooling crystallization temperature was 25℃, and the cooling crystallization time was 120 min; the mass ratio of crude isosorbide to carbonate a was 1:3, and the mass of the nucleating agent was 0.1% of the mass of crude isosorbide.

[0162] The isosorbide crystals obtained from the final dissolution-crystallization operation were analyzed by GC-MS, and no impurities were found; the yield of isosorbide crystals was 70%.

[0163] (4) Preparation of polycarbonate polymers;

[0164] The isosorbide crystals obtained from the last dissolution-crystallization operation in step (3) are directly mixed with carbonate b and then subjected to transesterification and polycondensation reactions in sequence to obtain polycarbonate polymers.

[0165] The molar ratio of isosorbide crystals to carbonate b is 1:1.06; the transesterification reaction is carried out at 150℃ for 2 hours under nitrogen or inert gas protection; the polycondensation reaction is carried out at 250℃ for 20 minutes under 150 Pa pressure.

[0166] The final polycarbonate polymer compound had a glass transition temperature of 171℃, an intrinsic viscosity of 50.10 mL / g, and a viscosity-average molecular weight of 28615 g / mol.

[0167] Example 6

[0168] A method for preparing a copolycarbonate polymer compound, comprising the following specific steps:

[0169] (1) Preparation of materials;

[0170] Isosorbide dinitrate: Manufacturer: Roquette (China) Fine Chemicals Co., Ltd.;

[0171] Strong base: KOH;

[0172] Crude isosorbide: Manufacturer is Shanghai Titan Co., Ltd., product number is 013709791;

[0173] Carbonate a: dipropyl carbonate;

[0174] Comonomer: Bisphenol A;

[0175] Carbonate C: Diphenyl carbonate;

[0176] (2) Preparation of nucleating agents;

[0177] The nucleating agent is obtained by mixing isosorbide in a molar ratio of 3:2 with a strong base and reacting at 85°C for 7 hours.

[0178] (3) Perform one dissolution-crystallization operation;

[0179] The dissolution-crystallization process is as follows: first, crude isosorbide is dissolved in carbonate a to obtain a solution, then a nucleating agent is added to the solution and cooled to crystallize isosorbide crystals, and then the isosorbide crystals are separated.

[0180] The dissolution temperature was 40℃, the dissolution time was 30 min, the cooling crystallization temperature was 0℃, and the cooling crystallization time was 60 min; the mass ratio of crude isosorbide to carbonate a was 1:1, and the mass of the nucleating agent was 0.05% of the mass of crude isosorbide.

[0181] The isosorbide crystals obtained by the dissolution-crystallization operation were analyzed by GC-MS, and no impurities were found; the yield of isosorbide crystals was 90%.

[0182] (4) Preparation of copolycarbonate polymers;

[0183] The comonomer and isosorbide crystals obtained from the last dissolution-crystallization operation in step (3) are directly mixed with carbonate C and then subjected to transesterification and polycondensation reactions in sequence to obtain copolycarbonate polymers.

[0184] The ratio of the total molar amount of comonomer and isosorbide crystals to the molar amount of carbonate C is 1:1.06, and the molar ratio of comonomer to isosorbide crystals is 3:7. The transesterification reaction is carried out at 150℃ for 2 hours under nitrogen or inert gas protection. The polycondensation reaction is carried out at 250℃ for 60 minutes under a pressure of 150 Pa.

[0185] The final obtained copolycarbonate polymer compound had an intrinsic viscosity of 50.69 mL / g and a viscosity-average molecular weight of 29032 g / mol.

[0186] Example 7

[0187] A method for preparing a copolycarbonate polymer compound, comprising the following specific steps:

[0188] (1) Preparation of materials;

[0189] Isosorbide dinitrate: Manufacturer: Roquette (China) Fine Chemicals Co., Ltd.;

[0190] Strong base: NaOH;

[0191] Crude isosorbide: Manufacturer is Shanghai Myriel Biochemical Technology Co., Ltd., product number is M04808;

[0192] Carbonate a: Diethyl carbonate;

[0193] Comonomer: 1,4-cyclohexanediethanol;

[0194] Carbonate C: Diphenyl carbonate;

[0195] (2) Preparation of nucleating agents;

[0196] The nucleating agent is obtained by mixing isosorbide in a molar ratio of 4:2 with a strong base and reacting at 90°C for 6 hours.

[0197] (3) Perform two dissolution-crystallization operations;

[0198] The first dissolution-crystallization operation is as follows: crude isosorbide is first dissolved in carbonate a to obtain a solution, then a nucleating agent is added to the solution and cooled to crystallize isosorbide crystals, and then the isosorbide crystals are separated; the second dissolution-crystallization operation differs from the first dissolution-crystallization operation in that crude isosorbide is replaced with the isosorbide crystals obtained in the first dissolution-crystallization operation.

[0199] The dissolution temperature was 45℃, the dissolution time was 40 min, the cooling crystallization temperature was 5℃, and the cooling crystallization time was 75 min; the mass ratio of crude isosorbide to carbonate a was 1:1.5, and the mass of the nucleating agent was 0.06% of the mass of crude isosorbide.

[0200] The isosorbide crystals obtained from the final dissolution-crystallization operation were analyzed by GC-MS, and no impurities were found; the yield of isosorbide crystals was 85%.

[0201] (4) Preparation of copolycarbonate polymers;

[0202] The comonomer and isosorbide crystals obtained from the last dissolution-crystallization operation in step (3) are directly mixed with carbonate C and then subjected to transesterification and polycondensation reactions in sequence to obtain copolycarbonate polymers.

[0203] The ratio of the total molar amount of comonomer and isosorbide crystals to the molar amount of carbonate C is 1:1.03, and the molar ratio of comonomer to isosorbide crystals is 3:7. The transesterification reaction is carried out at a temperature of 130℃ for 3 hours under nitrogen or inert gas protection. The polycondensation reaction is carried out at a temperature of 230℃ for 90 minutes under a pressure of 135 Pa.

[0204] The final obtained copolycarbonate polymer compound had an intrinsic viscosity of 48.64 mL / g and a viscosity-average molecular weight of 27607 g / mol.

[0205] Example 8

[0206] A method for preparing a copolycarbonate polymer compound, comprising the following specific steps:

[0207] (1) Preparation of materials;

[0208] Isosorbide dinitrate: Manufacturer: Roquette (China) Fine Chemicals Co., Ltd.;

[0209] Metal: Li;

[0210] Crude isosorbide: Manufacturer is Shanghai Myriel Biochemical Technology Co., Ltd., product number is M35263;

[0211] Carbonate a: dimethyl carbonate;

[0212] Comonomer: 1,4-Butanediol;

[0213] Carbonate C: Diphenyl carbonate;

[0214] (2) Preparation of nucleating agents;

[0215] The nucleating agent is obtained by mixing isosorbide in a molar ratio of 1:2 with a metal and reacting at 25°C for 3 hours.

[0216] (3) Perform three dissolution-crystallization operations;

[0217] The first dissolution-crystallization operation is as follows: crude isosorbide is first dissolved in carbonate a to obtain a solution, then a nucleating agent is added to the solution and cooled to crystallize isosorbide crystals, and then the isosorbide crystals are separated; the difference between the second and third dissolution-crystallization operations and the first dissolution-crystallization operation is that the crude isosorbide is replaced with the isosorbide crystals obtained in the previous dissolution-crystallization operation;

[0218] The dissolution temperature was 50℃, the dissolution time was 50 min, the cooling crystallization temperature was 10℃, and the cooling crystallization time was 90 min; the mass ratio of crude isosorbide to carbonate a was 1:2, and the mass of the nucleating agent was 0.07% of the mass of crude isosorbide.

[0219] The isosorbide crystals obtained from the final dissolution-crystallization operation were analyzed by GC-MS, and no impurities were found (e.g., Figure 1 (As shown); the yield of isosorbide crystals was 80%;

[0220] (4) Preparation of copolycarbonate polymers;

[0221] The comonomer and isosorbide crystals obtained from the last dissolution-crystallization operation in step (3) are directly mixed with carbonate C and then subjected to transesterification and polycondensation reactions in sequence to obtain copolycarbonate polymers.

[0222] The ratio of the total molar amount of comonomer and isosorbide crystals to the molar amount of carbonate C is 1:1, and the molar ratio of comonomer to isosorbide crystals is 3:7. The transesterification reaction is carried out at a temperature of 130℃ for 3 hours under nitrogen or inert gas protection. The polycondensation reaction is carried out at a temperature of 230℃ for 60 minutes under a pressure of 135 Pa.

[0223] The final obtained copolycarbonate polymer compound had an intrinsic viscosity of 44.94 mL / g and a viscosity-average molecular weight of 25069 g / mol.

[0224] Example 9

[0225] A method for preparing a copolycarbonate polymer compound, comprising the following specific steps:

[0226] (1) Preparation of materials;

[0227] Isosorbide dinitrate: Manufacturer: Roquette (China) Fine Chemicals Co., Ltd.;

[0228] Metal: Mg;

[0229] Crude isosorbide: Manufacturer is Sinopharm Chemical Reagent Co., Ltd., product number is 80075363;

[0230] Carbonate a: Methyl ethyl carbonate;

[0231] Comonomer: 1,5-pentanediol;

[0232] Carbonate C: Diphenyl carbonate;

[0233] (2) Preparation of nucleating agents;

[0234] The nucleating agent is obtained by mixing isosorbide in a molar ratio of 1:1 with a metal and reacting at 160°C for 8 hours.

[0235] (3) Perform 4 dissolution-crystallization operations;

[0236] The first dissolution-crystallization operation is as follows: crude isosorbide is first dissolved in carbonate a to obtain a solution, then a nucleating agent is added to the solution and cooled to crystallize isosorbide crystals, and then the isosorbide crystals are separated; the difference between the second to fourth dissolution-crystallization operations and the first dissolution-crystallization operation is that the crude isosorbide is replaced with the isosorbide crystals obtained in the previous dissolution-crystallization operation;

[0237] The dissolution temperature was 55℃, the dissolution time was 55 min, the cooling crystallization temperature was 15℃, and the cooling crystallization time was 105 min; the mass ratio of crude isosorbide to carbonate a was 1:2.5, and the mass of the nucleating agent was 0.08% of the mass of crude isosorbide.

[0238] The isosorbide crystals obtained from the final dissolution-crystallization operation were analyzed by GC-MS, and no impurities were found; the yield of isosorbide crystals was 75%.

[0239] (4) Preparation of copolycarbonate polymers;

[0240] The comonomer and isosorbide crystals obtained from the last dissolution-crystallization operation in step (3) are directly mixed with carbonate C and then subjected to transesterification and polycondensation reactions in sequence to obtain copolycarbonate polymers.

[0241] The ratio of the total molar amount of comonomer and isosorbide crystals to the molar amount of carbonate C is 1:1, and the molar ratio of comonomer to isosorbide crystals is 5:5. The transesterification reaction is carried out at a temperature of 120℃ for 3 hours under nitrogen or inert gas protection. The polycondensation reaction is carried out at a temperature of 240℃ for 90 minutes under a pressure of 120 Pa.

[0242] The final obtained copolycarbonate polymer compound had an intrinsic viscosity of 44.59 mL / g and a viscosity-average molecular weight of 24830 g / mol.

[0243] Example 10

[0244] A method for preparing a copolycarbonate polymer compound, comprising the following specific steps:

[0245] (1) Preparation of materials;

[0246] Isosorbide dinitrate: Manufacturer: Roquette (China) Fine Chemicals Co., Ltd.;

[0247] Metal: Ca;

[0248] Crude isosorbide: Manufacturer is Shanghai Maclean Biochemical Technology Co., Ltd., product number is C805218;

[0249] Carbonate a: a mixture of dimethyl carbonate and diethyl carbonate in a volume ratio of 3:1;

[0250] Comonomer: 1,6-hexanediol;

[0251] Carbonate C: Diphenyl carbonate;

[0252] (2) Preparation of nucleating agents;

[0253] The nucleating agent is obtained by mixing isosorbide in a molar ratio of 1:1 with a metal and reacting at 160°C for 10 hours.

[0254] (3) Perform 5 dissolution-crystallization operations;

[0255] The first dissolution-crystallization operation is as follows: crude isosorbide is first dissolved in carbonate a to obtain a solution, then a nucleating agent is added to the solution and cooled to crystallize isosorbide crystals, and then the isosorbide crystals are separated; the difference between the second to fifth dissolution-crystallization operations and the first dissolution-crystallization operation is that the crude isosorbide is replaced with the isosorbide crystals obtained in the previous dissolution-crystallization operation;

[0256] The dissolution temperature was 60℃, the dissolution time was 60 min, the cooling crystallization temperature was 25℃, and the cooling crystallization time was 120 min; the mass ratio of crude isosorbide to carbonate a was 1:3, and the mass of the nucleating agent was 0.1% of the mass of crude isosorbide.

[0257] The isosorbide crystals obtained from the final dissolution-crystallization operation were analyzed by GC-MS, and no impurities were found; the yield of isosorbide crystals was 70%.

[0258] (4) Preparation of copolycarbonate polymers;

[0259] The comonomer and isosorbide crystals obtained from the last dissolution-crystallization operation in step (3) are directly mixed with carbonate C and then subjected to transesterification and polycondensation reactions in sequence to obtain copolycarbonate polymers.

[0260] The ratio of the total molar amount of comonomer and isosorbide crystals to the molar amount of carbonate C is 1:1, and the molar ratio of comonomer to isosorbide crystals is 7:3. The transesterification reaction is carried out at a temperature of 110℃ for 4 hours under nitrogen or inert gas protection. The polycondensation reaction is carried out at a temperature of 210℃ for 120 minutes under a pressure of 120 Pa.

[0261] The final obtained copolycarbonate polymer compound had an intrinsic viscosity of 41.72 mL / g and a viscosity-average molecular weight of 22898 g / mol.

Claims

1. A nucleating agent for purification of isosorbide, characterized by, The structural formula is as follows: In the formula, X is Na or K.

2. A nucleating agent for isosorbide purification, characterized by, The structural formula is as follows: In the formula, X is Li.

3. A nucleating agent for isosorbide purification, characterized by, The structural formula is as follows: In the formula, Z is Mg or Ca.

4. A method of preparing a nucleating agent for the purification of isosorbide as claimed in claim 1, characterized in that, The nucleating agent for the purification of isosorbide is obtained by the reaction of refined isosorbide and strong alkali, wherein the strong alkali is NaOH or KOH.

5. The method of claim 4, wherein, The molar ratio of refined isosorbide to strong alkali is 3-4:

2.

6. The method of claim 4, wherein, The reaction temperature is 25-160 DEG C, and the reaction time is 3-10 h.

7. A method for preparing a nucleating agent for purification of isosorbide as claimed in claim 2 or 3, characterized in that, The nucleating agent for the purification of isosorbide is obtained by the reaction of refined isosorbide and metal, wherein the metal is Li, Mg or Ca.

8. The method of claim 7, wherein, The molar ratio of refined isosorbide to metal is 1:1-2.

9. The method of claim 7, wherein, The reaction temperature is 25-160 DEG C, and the reaction time is 3-10 h.

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