Preparation method for preparing polycarbonate polyol through catalytic irreversible polycondensation based on continuous flow technology

Abstract

The invention discloses a preparation method of polycarbonate polyol based on a continuous flow technology, and belongs to the technical field of organic synthesis. The method comprises the following steps: synthesizing the polycarbonate in a catalytic manner. Compared with an existing polycarbonate polyol synthesis mode, the method has the obvious advantages that the production repeatability is high, the difference between batches is small, the synthesis route is green and environment-friendly, byproducts can be recycled, and the like.

Description

Technical Field

[0001] The present invention belongs to the field of polymer synthesis and polycondensation, and particularly relates to a polycondensation method of a polymer having a carbonate functional group and a microfluidic preparation method of a polycarbonate polyol. Background Art

[0002] The catalytic polycondensation to prepare polycarbonate polyols is widely used in the preparation of polyurethane materials and is an important synthesis method. This method involves the polycondensation reaction of polyol monomers and organic carbonates under the action of a catalytic system. It is characterized in that the carbonate groups and aliphatic / alicyclic structural units are alternately distributed in the molecular chain of the obtained product, endowing the material with excellent weather resistance and thermal stability. This polycarbonate polyol exhibits significantly improved chemical stability [Cui, Minghui, et al. "Developments of polyurethane in biomedical applications: A review." Resources Chemicals and Materials (2023)], anti-photoaging property, and thermo-oxidative stability [Chattopadhyay, D.K., and Dean C. Webster. "Thermal stability and flame retardancy of polyurethanes." Progress in Polymer Science 34.10 (2009): 1068 - 1133]. Its molecular chain parameters can be regulated by reaction conditions to meet the requirements of different application scenarios. The polyurethane materials prepared based on this synthetic product can be widely used in microelectronic packaging, the construction industry [Li, Xianrui, et al. "Recent applications and developments of Polyurethane materials in pavement engineering." Construction and Building Materials 304 (2021): 124639], medical devices [Joseph, J., et al. "Biomedical applications of polyurethane materials and coatings." Transactions of the IMF 96.3 (2018): 121 - 129], and special coatings fields. Their products show excellent property retention rates in extremely humid and hot or chemically corrosive environments. The traditional methods for synthesizing polycarbonate polyols are usually carried out in a stirred-tank reactor. The stirred-tank reactor is large in volume, prone to uneven mixing, and has low production efficiency and uncontrollable residence time [Li, Junhua, et al. "Continuously Stirred Tank Reactor for Pharmaceutical and Chemical Applications." Pharmaceutical Fronts (2024)].Therefore, the research on the catalytic polycondensation of polycarbonate polyols based on continuous flow technology has attracted extensive attention.

[0003] At present, some important achievements have been made in the research on the catalytic polycondensation of polycarbonate polyols. First of all, the selection of the reactor is the key. Researchers have found that different types of reactors have a significant impact on the synthesis of polycarbonate polyols. Commonly used reactors include batch reactors, continuous flow reactors, and microfluidic reactors, etc. Secondly, the optimization of reactor conditions is a key factor in improving the synthesis efficiency and product quality. Researchers have achieved the synthesis of polycarbonate polyols by adjusting parameters such as the rate, pressure, and mixing efficiency of the reactor. In addition, some innovative reactor designs and process improvements have also provided new technical paths and solutions for the catalytic polycondensation production of polycarbonate polyols.

[0004] However, there are still some challenges and problems in the current catalytic polycondensation production of polycarbonate polyols. The key to synthesizing polycarbonate polyols is the selection of the reactor, and different types of reactors have a significant impact on the reaction efficiency and product performance. For example, although the traditional batch reactor has a simple structure, it is prone to low mass transfer efficiency and uneven product replication distribution. At the same time, the polycondensation reaction occurrence between different batches is reduced, limiting its industrial application. In contrast, the microfluidic reactor eliminates high-efficiency mass transfer, precise temperature control, and a stable reaction environment [Tanimu, Abdulkadir, Stephan Jaenicke, and Khalid Alhooshani. "Heterogeneous catalysis in continuous flow microreactors: A review of methods and applications." Chemical Engineering Journal 327 (2017): 792 - 821.], and has gradually become a research hotspot. However, there are still technical problems in the design and large-scale application of microfluidic reactors, and the development of new reactors suitable for catalytic polycondensation reactions remains an important research direction at present. Summary of the Invention

[0005] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a non-reversible and reproducible high-efficiency polycondensation method carried out in a continuous flow and a preparation method of polycarbonate polyols. Using diol as a substrate, polycarbonate polyols are prepared by polycondensation, and the obtained polycarbonate polyols have high commercial application potential in fields such as the microelectronics industry, chip packaging, construction, and medical treatment.

[0006] The present invention first proposes to use a continuous flow reactor to achieve large-scale preparation of polycarbonate polyols in a pipeline based on an irreversible reaction. The purity of the reaction by-product phenol is relatively high, and no column chromatography is required.

[0007] To expand the applications of polycarbonate polyols in the microelectronics industry, chip packaging, construction, and medical fields, the present invention is based on practical applications, discovers and solves problems, and uses various diols to prepare polycarbonate polyols with various substituents. This preparation method is first proposed and applied to the synthesis of high-value-added polycarbonate polyols.

[0008] The technical solution to achieve the above object is as follows:

[0009] A method for preparing polycarbonate polyols, the steps of which are:

[0010] Synthesis of polycarbonate polyols: The diol substrate and carbonate are polycondensed under the action of an organic catalyst to form polycarbonate

[0011] polyol; the molecular formula of the polycarbonate polyol is shown in formula (I):

[0012]

[0013] R is a functional group, and the diol containing R is selected from the following structures:

[0014]

[0015] The carbonate used for preparing the polycarbonate compound is: diphenyl carbonate.

[0016] The catalyst used for preparing polycarbonate polyols is: methanesulfonic acid.

[0017] The specific method for polycondensing to prepare polycarbonate polyols is: Under heating, methanesulfonic acid, diphenyl carbonate and diol are mixed evenly, and then put into a continuous flow reactor. After reacting fully for 1-8 hours, polycarbonate polyols are obtained.

[0018] Beneficial effects

[0019] Adopting the technical solution of the present invention can achieve at least one of the following beneficial effects:

[0020] (1) The present invention can efficiently synthesize polycarbonate polyols with high added value through the above-mentioned catalytic system. Compared with the polymerization using a batch reactor in the prior art, it has the characteristics of high repeatability and a safer production environment. Polycarbonate polyols are materials with good hydrolysis resistance, light resistance, oxidation degradation resistance, and heat resistance. They can be used to prepare elastomers, paints, coatings, or adhesives, and have high strength, good weather resistance, and chemical stability, etc., showing great potential for commercial applications in the microelectronics industry, chip packaging, construction, medical treatment, and other fields.

[0021] (2) The preparation method of the present invention is used to prepare polycarbonate polyols. The microreactor has a large specific surface area and faster heat dissipation or heating. Compared with the known technologies, the present invention can better control the temperature and obtain a more uniform product.

[0022] (3) The continuous flow reactor used in the present invention has a small volume and less potential danger. The continuous flow production method can reduce the differences between batches, which is beneficial to improving production efficiency and is safer and more efficient.

[0023] (4) The diols, carbonates, and catalysts used in the present invention are easily obtained and have a wide range of sources. Moreover, no solvent is required, which is beneficial to reducing production costs and has obvious economic advantages.

[0024] (5) The by-product phenol in the present invention can be recycled, which is beneficial to reducing production costs and has significant economic advantages.

[0025] In summary, compared with other existing systems, the present invention has obvious advantages such as easy control, easy preparation, safety, and high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The embodiments of the present invention will be described in detail with reference to the accompanying drawings, where

[0027] Figure 1 : 1H NMR spectrum of the carbonate product in Example 1

[0028] Figures 2 to 8 : 1H NMR spectra of the carbonate products in Examples 2 - 8 in sequence DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The present invention can be further illustrated by the following examples, which are for illustrative purposes only and not intended to limit the present invention. Any ordinary technician in the art can understand that these examples do not limit the present invention in any way and can make appropriate modifications and data transformations without departing from the essence and scope of the present invention.

[0030] The 1H NMR spectra involved in the examples were measured using a Bruker Ascend TM-400 nuclear magnetic resonance spectrometer from Bruker Corporation, and the deuterated reagent used was deuterated chloroform (CDCl3).

[0031] All raw materials used in the following examples were purchased from Alfa Aesar.

[0032] The glycols used in the examples have the following structures:

[0033]

[0034] Example 1:

[0035] Methanesulfonic acid (0.064 g, 0.66 mmol, 0.03 equiv), 1,4-butanediol (2 g, 0.022 mol, 1.0 equiv), and diphenyl carbonate (4.28 g, 0.02 mol, 0.9 equiv) were added to a reaction flask. The reaction was carried out in a continuous flow tube at 160 °C for 3 hours. The resulting product was an orange-red clear liquid, and the product was purified by vacuum distillation with a yield of 85%. The 1H NMR spectrum of the product is as Figure 1 shown (nuclear magnetic resonance hydrogen spectrum, 400 Hz, CDCl3). The spectral data are as follows:

[0036] 1 H NMR (400 MHz, Chloroform-d) δ 4.16 (s, 1H), 1.77 (s, 1H).

[0037] Example 2:

[0038] Methanesulfonic acid (0.055 g, 0.57 mmol, 0.03 equiv), 1,5-pentanediol (2 g, 0.019 mol, 1.0 equiv), and diphenyl carbonate (3.70 g, 0.017 mol, 0.9 equiv) were added to a reaction flask. The reaction was carried out in a continuous flow tube at 160 °C for 3 hours. The resulting product was an orange-red clear liquid, and the product was purified by vacuum distillation with a yield of 94%. The 1H NMR spectrum of the product is as Figure 1 shown (nuclear magnetic resonance hydrogen spectrum, 400 Hz, CDCl3). The spectral data are as follows:

[0039] 1 H NMR (400 MHz, Chloroform-d) δ 4.13 (s, 1H), 1.71 (s, 1H), 1.47 (s, 1H).

[0040] Example 3:

[0041] Add methanesulfonic acid (0.049 g, 0.51 mmol, 0.03 equiv), 1,6-hexanediol (2 g, 0.017 mol, 1.0 equiv), and diphenyl carbonate (3.26 g, 0.015 mol, 0.9 equiv) to the reaction flask. Place it in a continuous flow pipeline at 160 °C and react for 3 hours. The resulting product is an orange-red clear liquid. The product is purified by vacuum distillation, and the yield is 92%. The 1H NMR spectrum of the product is as shown in Figure 1 shown, (1H NMR, 400 Hz, CDCl3). The spectral data are as follows:

[0042] 1 1H NMR (400 MHz, Chloroform-d) δ 4.12 (s, 1H), 1.68 (s, 1H), 1.41 (s, 1H).

[0043] Example 4:

[0044] Add methanesulfonic acid (0.044 g, 0.46 mmol, 0.03 equiv), 1,7-heptanediol (2 g, 0.015 mol, 1.0 equiv), and diphenyl carbonate (2.92 g, 0.014 mol, 0.9 equiv) to the reaction flask. Place it in a continuous flow pipeline at 160 °C and react for 3 hours. The resulting product is an orange-red clear liquid. The product is purified by vacuum distillation, and the yield is 94%. The 1H NMR spectrum of the product is as shown in Figure 1 shown, (1H NMR, 400 Hz, CDCl3). The spectral data are as follows:

[0045] 1 1H NMR (400 MHz, Chloroform-d) δ 4.11 (s, 1H), 1.66 (s, 1H), 1.37 (s, 2H).

[0046] Example 5:

[0047] Add methanesulfonic acid (0.039 g, 0.41 mmol, 0.03 equiv), 1,8-octanediol (2 g, 0.014 mol, 1.0 equiv), and diphenyl carbonate (2.64 g, 0.012 mol, 0.9 equiv) to the reaction flask. Place it in a continuous flow pipeline at 160 °C and react for 3 hours. The resulting product is an orange-red clear liquid. The product is purified by vacuum distillation, and the yield is 95%. The 1H NMR spectrum of the product is as shown in Figure 1 shown, (1H NMR, 400 Hz, CDCl3). The spectral data are as follows:

[0048] 11H NMR (400 MHz, Chloroform-d) δ 4.10 (s, 1H), 1.65 (s, 1H), 1.32 (s, 2H).

[0049] Example 6:

[0050] Methanesulfonic acid (0.036 g, 0.37 mmol, 0.03 equiv), 1,9-nonanediol (2 g, 0.013 mol, 1.0 equiv), and diphenyl carbonate (2.40 g, 0.011 mol, 0.9 equiv) were added to a reaction flask. The reaction was carried out in a continuous flow tube at 160 °C for 3 hours. The resulting product was an orange-red clear liquid, and the product was purified by vacuum distillation with a yield of 99%. The 1H NMR spectrum of the product is as Figure 1 shown, (1H NMR spectrum, 400 Hz, CDCl3). The spectral data are as follows:

[0051] 1 1H NMR (400 MHz, Chloroform-d) δ 4.11 (s, 1H), 1.66 (s, 1H), 1.30 (s, 3H).

[0052] Example 7:

[0053] Methanesulfonic acid (0.033 g, 0.34 mmol, 0.03 equiv), 1,10-decanediol (2 g, 0.011 mol, 1.0 equiv), and diphenyl carbonate (2.21 g, 0.010 mol, 0.9 equiv) were added to a reaction flask. The reaction was carried out in a continuous flow tube at 160 °C for 3 hours. The resulting product was an orange-red clear liquid, and the product was purified by vacuum distillation with a yield of 99%. The 1H NMR spectrum of the product is as Figure 1 shown, (1H NMR spectrum, 400 Hz, CDCl3). The spectral data are as follows:

[0054] 1 1H NMR (400 MHz, Chloroform-d) δ 4.11 (s, 1H), 1.66 (s, 1H), 1.28 (s, 3H).

[0055] Example 8:

[0056] Add methanesulfonic acid (0.055 g, 0.57 mmol, 0.03 equiv), neopentyl glycol (2 g, 10 mmol, 1.0 equiv), 1,4-cyclohexanedimethanol (1.40 g, 10 mmol, 1.0 equiv), and diphenyl carbonate (3.70 g, 0.017 mol, 0.9 equiv) into the reaction flask. Place it in a continuous flow pipeline at 160 °C for reaction for 3 hours. The obtained product is an orange-red clear liquid. The product is purified by vacuum distillation, and the yield is 81%. The hydrogen spectrum of the product is as Figure 1 shown, (1H NMR, 400 Hz, CDCl3). The spectral data are:

[0057] 1 H NMR (400 MHz, Chloroform-d) δ 4.12 - 3.97 (m, 14H), 3.52 (d, J = 4.9 Hz, 1H), 1.99 (s, 1H), 1.68 - 1.53 (m, 15H), 1.48 (s, 1H), 1.35 (d, J = 24.8 Hz, 12H).

Claims

1. A method for preparing a polycarbonate polyol, characterized in that: It includes the following steps: (1) Synthesis of polycarbonate polyol: A diol substrate and diphenyl carbonate are polycondensed under the action of a catalyst to form a polycarbonate polyol; the molecular formula of the polycarbonate polyol is shown in formula (I): R is a functional group, and the diol containing R is selected from the following structures:

2. The preparation method according to claim 1, wherein: The catalyst is methanesulfonic acid.

3. The preparation method according to claim 1, characterized in that: The carbonate used for polycondensation is diphenyl carbonate.

4. The preparation method according to claim 1, wherein: The molar ratio of the diol, carbonate to the catalyst is 1:0.9:0.003 to 1:1.99:0.

3.

5. The preparation method according to claim 1, characterized in that: The said step is carried out in a continuous flow reactor, reacting at 50-200 °C for 1-8 hours.

Images