Process for preparing an alicyclic polycarbonate

Abstract

A method for preparing a high-molecular-weight alicyclic polycarbonate comprises: dissolving 2,2-bis(4-hydroxycyclohexyl)propane in the presence of a first solvent, an organic base catalyst, and a co-catalyst to form a mixed solution; and adding bis(trichloromethyl)carbonate dissolved in a second solvent to the mixed solution for a polycondensation reaction to produce an alicyclic polycarbonate having a peak molecular weight greater than 12,000. The preparation method of the present invention provides the alicyclic polycarbonate with high molecular weight and high purity, thus meeting the requirements for use in food containers, optical products, and medical products, increasing its application value.

Description

Technical Field

[0001] The present invention relates to a method for preparing polycarbonate, in particular to a method for preparing alicyclic polycarbonate. Background Art

[0002] Polycarbonate (PC) is an engineering plastic with excellent comprehensive performance. It has the characteristics of high temperature resistance, high transparency, high strength, impact resistance and high thermal resistance. It is widely used in food packaging, medical devices, building materials, electronic computers, automobiles, aerospace and optics. Among them, bisphenol A (BPA) type aromatic polycarbonate is the most common.

[0003] However, due to the benzene ring structure of this aromatic polycarbonate, the resulting polycarbonate is not only not resistant to UV light exposure, but the residual bisphenol A monomer (BPA, 2,2-bis(4-hydroxyphenyl)propane) in bisphenol A aromatic polycarbonate also has environmental hormonal issues such as endocrine disruption and premature puberty in females. Therefore, research on developing alternative monomers to replace bisphenol A has attracted considerable attention. In particular, hydrogenated bisphenol A (HBPA, 2,2-bis(4-hydroxycyclohexyl)propane), which has a similar structure to bisphenol A but lacks a benzene ring structure, is an ideal alternative to bisphenol A. However, there are currently no specific reports on the industrial production of alicyclic polycarbonates, either domestically or internationally.

[0004] According to the literature, the synthesis methods for alicyclic polycarbonates can be divided into phosgene and non-phosgene methods. However, the phosgene method is highly hazardous, and phosgene sources are difficult to obtain. The non-phosgene method, on the other hand, must be carried out at high temperature and low pressure, and its reaction conditions are more stringent than those of the phosgene method. Furthermore, the alicyclic polycarbonates produced by existing technologies have low molecular weights, making them difficult to replace the original polycarbonate materials. Therefore, it is necessary to develop a method for efficiently producing high-molecular-weight alicyclic polycarbonates to address the problems of these existing technologies. Summary of the Invention

[0005] To solve the above-mentioned problems, the present invention provides a method for preparing an alicyclic polycarbonate, comprising: dissolving 2,2-bis(4-hydroxycyclohexyl)propane in the presence of a first solvent, an organic base catalyst, and a co-catalyst to form a mixed solution, wherein the content of 2,2-bis(4-hydroxycyclohexyl)propane in the mixed solution is 0.5 to 1.0 volume mol concentration; and adding bis(trichloromethyl)carbonate dissolved in a second solvent to the mixed solution to carry out a polycondensation reaction, thereby preparing an alicyclic polycarbonate having a peak molecular weight greater than 12,000.

[0006] In a specific embodiment of the present invention, the polydispersity index (PDI value) of the prepared alicyclic polycarbonate is 1.7 or less.

[0007] In a specific embodiment of the present invention, the first solvent in the mixed solution is selected from one of the group consisting of toluene, dichloromethane, chloroform, chlorobenzene, adiponitrile, 2,6-dichlorotoluene, tetrahydrofuran and pyridine. Preferably, the first solvent selects a solvent having a boiling point higher than 60°C and containing chlorine, such as chloroform, chlorobenzene and 2,6-dichlorotoluene. In another specific embodiment, the first solvent can select a solvent having a boiling point higher than 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190°C and a boiling point lower than 200°C. In addition, the second solvent for dissolving bis(trichloromethyl)carbonate is the same as the first solvent for dissolving 2,2-bis(4-hydroxycyclohexyl)propane. For example, a solvent selected from the group consisting of toluene, dichloromethane, chloroform, chlorobenzene, adiponitrile, 2,6-dichlorotoluene, tetrahydrofuran and pyridine can be selected. In addition, no aqueous solvent is added in the present invention to avoid affecting the reaction.

[0008] In a specific embodiment of the present invention, the feed rate of bis(trichloromethyl)carbonate is 0.05 to 0.5 g / min. Specifically, bis(trichloromethyl)carbonate is dissolved in the second solvent to form a bis(trichloromethyl)carbonate solution, and the solution is slowly added to the mixed solution in batches. The feed rate of bis(trichloromethyl)carbonate refers to the amount of bis(trichloromethyl)carbonate in the bis(trichloromethyl)carbonate solution.

[0009] In one embodiment of the present invention, the molar ratio of 2,2-bis(4-hydroxycyclohexyl)propane to bis(trichloromethyl)carbonate is 1:1 to 4:1.

[0010] In a specific embodiment of the present invention, the organic base catalyst is a nitrogen-containing organic base, for example, at least one selected from the group consisting of triethylamine, pyridine, 3-methylpiperidine, 4-methylpiperidine, and 4-dimethylaminopyridine (DMAP). In a specific embodiment of the present invention, the molar ratio of the organic base catalyst to bis(trichloromethyl)carbonate is 0.01:1 to 0.3:1.

[0011] In a specific embodiment, this promotor is triethylamine or pyridine. In the present invention, promotor is different from organic base catalyst. If organic base catalyst is selected from at least one of the group consisting of 3-methyl piperidine, 4-methyl piperidine and 4-dimethylamino pyridine (DMAP), then promotor is triethylamine or pyridine. Specifically, the combination of this catalyst / promotor is selected from the one of triethylamine / pyridine, pyridine / triethylamine, 3-methyl piperidine / pyridine, 3-methyl piperidine / triethylamine, 4-methyl piperidine / pyridine, 4-methyl piperidine / triethylamine, 4-dimethylamino pyridine / pyridine and 4-dimethylamino pyridine / triethylamine. In a specific embodiment of the present invention, the mol ratio of this promotor and bis (trichloromethyl) carbonate is 2: 1 to 18: 1. In other words, the consumption of promotor can be greater than organic base catalyst.

[0012] In a specific embodiment, the polycondensation reaction temperature is 15 to 180°C, for example, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170 or 180°C.

[0013] In another embodiment, the polycondensation reaction time is 4 to 24 hours, for example, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24 hours.

[0014] In another specific embodiment, the polycondensation reaction temperature is set to a two-stage temperature comprising a first reaction temperature and a second reaction temperature greater than the first reaction temperature, the first reaction temperature is 15 to 60°C, and the reaction time in the first reaction temperature stage is 1 to 4 hours; the second reaction temperature is 60 to 180°C, and the reaction time in the second reaction temperature stage is 8 to 15 hours.

[0015] According to the present invention, the solubility of 2,2-bis(4-hydroxycyclohexyl)propane is increased by using an organic base catalyst and a co-catalyst, enabling its efficient participation in the reaction. In particular, the use of the co-catalyst effectively controls the activity of the organic base catalyst, providing immediate reactivity during the subsequent polycondensation. This allows the preparation of the mixed solution at room temperature, eliminating the risk of hydrolysis caused by reactant precipitation and facilitating mass production. Furthermore, by adding the reactive monomer bis(trichloromethyl)carbonate in batches, the alicyclic polycarbonate of the present invention can be prepared under mild reaction conditions.

[0016] Furthermore, due to the high reaction selectivity of the preparation method of the present invention, the alicyclic polycarbonate produced has high molecular weight and high purity, meeting the requirements for use in food containers, optical and medical products, thereby increasing its application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The embodiments of the present disclosure are described by way of example with reference to the accompanying drawings:

[0018] Figure 1 : is a Fourier transform infrared spectrum of an embodiment of the present invention, wherein the solid line is 2,2-bis(4-hydroxycyclohexyl)propane (HBPA) and the dotted line is the product alicyclic polycarbonate (HPC). DETAILED DESCRIPTION

[0019] The following describes the embodiments of the present invention by means of specific embodiments. Those skilled in the art can easily understand the advantages and effects of the present invention from the content described in this specification. The present invention can also be implemented or applied through other different embodiments. The details in this specification can also be based on different viewpoints and applications, and given different modifications and changes without departing from the spirit described in the present invention. In addition, all ranges and values herein are inclusive and combinable. Any numerical value or point falling within the range described herein, such as any integer, can be used as a minimum value or maximum value to derive a lower range, etc.

[0020] According to the present invention, a method for preparing an alicyclic polycarbonate comprises: dissolving 2,2-bis(4-hydroxycyclohexyl)propane at room temperature in the presence of a first solvent, an organic base catalyst, and a co-catalyst to form a mixed solution; and adding bis(trichloromethyl)carbonate dissolved in a second solvent at room temperature to the mixed solution for polycondensation to obtain an alicyclic polycarbonate having the following formula (I), wherein n is greater than 40,

[0021]

[0022] The alicyclic polycarbonate prepared by the above method can have a peak molecular weight greater than 12,000. In one embodiment, n is 40 to 80. In one embodiment, the alicyclic polycarbonate prepared has a polydispersity index (PDI value) of 1.7 or less.

[0023] Herein, 2,2-bis(4-hydroxycyclohexyl)propane having a purity of 95% or more is used.

[0024] In a specific embodiment of the present invention, the first solvent in the mixed solution is selected from one of the group consisting of toluene, dichloromethane, chloroform, chlorobenzene, adiponitrile, 2,6-dichlorotoluene, tetrahydrofuran and pyridine. Preferably, the first solvent selects a solvent having a boiling point higher than 60°C and containing chlorine, such as chloroform, chlorobenzene and 2,6-dichlorotoluene, to increase the reaction rate of the polycondensation reaction. In another specific embodiment, the first solvent may select a solvent having a boiling point higher than 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190°C and a boiling point lower than 200°C. In addition, the second solvent for dissolving bis(trichloromethyl)carbonate is the same as the first solvent for dissolving 2,2-bis(4-hydroxycyclohexyl)propane. For example, the solvent may be one selected from the group consisting of toluene, dichloromethane, chloroform, chlorobenzene, adiponitrile, 2,6-dichlorotoluene, tetrahydrofuran, and pyridine.

[0025] In a specific embodiment of the present invention, during the polycondensation reaction, the content of 2,2-bis(4-hydroxycyclohexyl)propane in the mixed solution is 0.5 to 1.0 volume molar concentration (M).

[0026] In other embodiments, the content of 2,2-bis(4-hydroxycyclohexyl)propane in the mixed solution may be 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9 or 0.95 M, but is not limited thereto.

[0027] The process of dissolving 2,2-bis(4-hydroxycyclohexyl)propane to form a mixed solution is carried out at room temperature and pressure, and continuous stirring is required to increase the collision between 2,2-bis(4-hydroxycyclohexyl)propane and the organic base catalyst and co-catalyst and promote dissolution. After complete dissolution, the polycondensation reaction can be carried out. In an embodiment of the present invention, the reaction apparatus used in the preparation method of the present invention further includes a stirring device, such as a stirred tank reactor, and the rotation speed of the stirring device is controlled to be 50 to 500 revolutions per minute. In a specific embodiment, the stirring device can be selected from a propeller stirrer, a turbine stirrer, a paddle stirrer, an anchor stirrer, a folding blade stirrer, a side-entry stirrer, a propeller stirrer, a magnetic heating stirrer, or a ribbon stirrer.

[0028] In other embodiments, the rotational speed of the stirring device may be 75, 100, 150, 200, 250, 300, 350, 400 or 450 rpm, but is not limited thereto.

[0029] Herein, the organic base catalyst is a nitrogen-containing organic base that facilitates the polycondensation reaction under mild conditions. Examples of the organic base catalyst include triethylamine, pyridine, 3-methylpiperidine, 4-methylpiperidine, or 4-dimethylaminopyridine. In a specific embodiment of the present invention, the molar ratio of the organic base catalyst to bis(trichloromethyl)carbonate is 0.01:1 to 0.3:1.

[0030] In another specific embodiment, the organic base catalyst is 4-dimethylaminopyridine, and the molar ratio of 4-dimethylaminopyridine to bis(trichloromethyl)carbonate is 0.01:1 to 0.3:1.

[0031] In other embodiments, the molar ratio of 4-dimethylaminopyridine to bis(trichloromethyl)carbonate can be 0.05:1, 0.1:1, 0.15:1, 0.2:1 or 0.25:1, but is not limited thereto.

[0032] Herein, the co-catalyst helps to evenly distribute 2,2-bis(4-hydroxycyclohexyl)propane and the catalyst and maintain its stable pH value. The co-catalyst is preferably an organic base compound.

[0033] In one embodiment, the co-catalyst is triethylamine or pyridine, and the co-catalyst is different from the organic base catalyst. In some embodiments, the catalyst / co-catalyst combination is selected from the group consisting of triethylamine / pyridine, pyridine / triethylamine, 3-methylpiperidine / pyridine, 3-methylpiperidine / triethylamine, 4-methylpiperidine / pyridine, 4-methylpiperidine / triethylamine, 4-dimethylaminopyridine / pyridine, and 4-dimethylaminopyridine / triethylamine.

[0034] In the reaction system, when a nitrogen-containing heterocycle with a substituent is selected as an organic base catalyst, such as 3-methylpiperidine, 4-methylpiperidine or 4-dimethylaminopyridine, due to the steric hindrance in its structure, if a co-catalyst is not present, by-products are easily formed during the reaction, affecting the purity of the product; in the preparation method of the present invention, by using a co-catalyst, such as triethylamine or pyridine, the side reaction of the organic base catalyst can be suppressed, and the polycondensation reaction tends to form alicyclic polycarbonates, so the amount of the co-catalyst should be higher than the amount of the catalyst, but not too high; however, if the amount of the co-catalyst is too high, it is easy to cause the reactant 2,2-bis(4-hydroxycyclohexyl)propane to be directly hydrolyzed, thereby affecting the reaction yield. In a specific embodiment, the molar ratio of the co-catalyst to bis(trichloromethyl)carbonate is 2:1 to 18:1. For example, the co-catalyst is pyridine, and the molar ratio of pyridine to bis(trichloromethyl)carbonate is 2:1 to 18:1.

[0035] In other embodiments, the molar ratio of the co-catalyst to bis(trichloromethyl)carbonate may be 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1 or 17:1, but is not limited thereto.

[0036] Furthermore, the method and order of introduction of the organic base catalyst and the co-catalyst into the reaction apparatus are not limited, but it is preferred that the organic base catalyst and the co-catalyst are introduced into the reaction apparatus simultaneously.

[0037] In the preparation method of the present invention, the molar ratio of 2,2-bis(4-hydroxycyclohexyl)propane to bis(trichloromethyl)carbonate is 1:1 to 4:1.

[0038] In other embodiments, the molar ratio of 2,2-bis(4-hydroxycyclohexyl)propane to bis(trichloromethyl)carbonate may be 1.5:1, 2:1, 2.5:1, 2.7:1, 3:1, 3.2:1, 3.5:1, or 3.7:1, but is not limited thereto.

[0039] To optimize the reaction and increase the molecular weight and purity of the product, the polycondensation reaction of the present invention may include at least one temperature setting, or a continuous temperature increase setting within a temperature range, and the reaction temperature is in the range of 15 to 180°C.

[0040] In other embodiments, the reaction temperature of the polycondensation reaction may be 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160 or 170° C., but is not limited thereto.

[0041] In another specific embodiment, the polycondensation reaction temperature is a two-stage temperature setting selected from the range of 15 to 180°C; for example, the first reaction temperature of the polycondensation reaction can be 15 to 60°C, such as 20, 30, 40 or 50°C, and the reaction time is 1 to 4 hours; the second reaction temperature of the polycondensation reaction is greater than the first reaction temperature and can be 60 to 180°C, such as 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170 or 180°C, and the reaction time is 8 to 15 hours, but not limited thereto.

[0042] In another embodiment, the polycondensation reaction temperature is set to a continuously elevated temperature within a range of 15 to 180° C. The continuously elevated temperature setting range for the polycondensation reaction may include, but is not limited to, 15 to 100° C., 15 to 120° C., 15 to 140° C., 25 to 100° C., 25 to 120° C., or 25 to 140° C.

[0043] In one embodiment, the reaction time of the polycondensation reaction is 4 to 24 hours.

[0044] In other embodiments, the reaction time of the polycondensation reaction can be 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, or 23 hours.

[0045] Compared to the phosgene method, the present invention dissolves solid bis(trichloromethyl)carbonate in a second solvent and allows for gradual, batch-wise introduction into the reaction system, enabling more precise control of the polycondensation reaction rate and selectivity. In one embodiment, the bis(trichloromethyl)carbonate feed rate is 0.05 to 0.5 g / min.

[0046] After the polycondensation reaction, the reaction process forms a viscous by-product, which is an incompletely converted product and is not conducive to the downstream application of the reaction product. Therefore, a solvent that does not dissolve the alicyclic polycarbonate of formula (I) and has solubility in the by-product and unreacted 2,2-bis(4-hydroxycyclohexyl)propane must be selected to precipitate the product of the present invention from the reaction mixture.

[0047] The solvent that does not dissolve the alicyclic polycarbonate of formula (I) is an alcohol solvent, among which methanol is particularly preferred.

[0048] The features and effects of the present invention are further described in detail below through specific examples, but the scope of the present invention is not limited by the examples.

[0049] Comparative Example 1

[0050] 10 g of 2,2-bis(4-hydroxycyclohexyl)propane, 25 ml of chlorobenzene and 90 ml of a 5 wt% aqueous sodium hydroxide solution were placed in a three-necked flask equipped with a mechanical stirrer, a condenser and a feeding funnel, and the temperature was set to -8°C for stirring; after thorough mixing, 0.21 g of an organic base catalyst triethylamine was added at -8°C.

[0051] Next, 10 g of bis(trichloromethyl)carbonate was dissolved in 20 ml of chlorobenzene to prepare a bis(trichloromethyl)carbonate solution. This bis(trichloromethyl)carbonate solution was slowly added dropwise to the three-necked flask via a dropping funnel. During the addition and stirring process, the reaction solution was slowly warmed to room temperature. After 30 minutes of addition, the polycondensation reaction began. After 12 hours of reaction, methanol was added to the reaction solution. No product precipitated, primarily because the 2,2-bis(4-hydroxycyclohexyl)propane was insoluble in the aqueous sodium hydroxide solution and therefore failed to participate in the reaction.

[0052] Example 1:

[0053] 10 g of 2,2-bis(4-hydroxycyclohexyl)propane (HBPA), 25 ml of the reaction solvent chlorobenzene, 9.32 g of the co-catalyst (Co-cat) pyridine, and 0.26 g of the organic base catalyst (Org-cat) 4-dimethylaminopyridine (DMAP) were placed in a three-necked flask equipped with a mechanical stirrer, a condenser, and a feeding funnel to form a mixed solution, and stirred at room temperature and pressure (25° C., 1 atm), wherein the 2,2-bis(4-hydroxycyclohexyl)propane content in the mixed solution was 0.95 M.

[0054] Next, at 25°C, 10 g of bis(trichloromethyl) carbonate (BTC) was dissolved in 20 ml of chlorobenzene to prepare a bis(trichloromethyl) carbonate solution. The bis(trichloromethyl) carbonate solution was slowly added dropwise to the mixed solution via a dropping funnel over 30 minutes for a 12-hour polycondensation reaction. The polycondensation reaction temperature was set in two stages: a first reaction temperature of 15°C for 2 hours and a second reaction temperature of 120°C for 10 hours. After the polycondensation reaction was completed, methanol was added to the reaction solution. After evacuation, filtration, and drying, a white alicyclic polycarbonate product was obtained.

[0055] The above products were subjected to the following test analysis, and the results are recorded in Table 1:

[0056] (1) Fourier transform infrared spectroscopy analysis: The reactant 2,2-bis(4-hydroxycyclohexyl)propane (HBPA) and the alicyclic polycarbonate (HPC) product prepared above were prepared into powder samples, and Fourier transform infrared spectrometer (PerkinElmer, Spectrum Two) was used to analyze the reaction mixture at a wave number of 400 to 4000 cm -1 Analyze within the range and record the measured results in Figure 1 .

[0057] (2) Molecular weight determination: The peak molecular weight and polydispersity index (PDI value) of the product were detected using a gel permeation chromatograph (GPC, Waters, 1515 System), wherein the operating conditions were as follows: (1) Mobile phase: 1.0 ml / min, THF; (2) Detector model: Waters 2414 refractive index detector; Detection temperature: 40°C; (3) Concentration of the product used for GPC detection: 10 mg / ml; (4) Injection volume: 3 μL; (5) Chromatographic column model: Phenogel 00H-0442-K0, 00H-0443-K0, 00H-0444-K0.

[0058] According to the above analysis, the peak molecular weight of the product was measured to be 17,428, the PDI value was 1.5, and in the Fourier transform infrared spectroscopy analysis, the absorption peak of OH of the reactant HBPA was 3305 cm-1; the absorption peaks of C=O and OCO of the prepared HPC product were 1734 cm-1 and 1251 cm-1, respectively.

[0059] Example 2:

[0060] The preparation and analysis methods for the alicyclic polycarbonate were the same as in Example 1, except that the amount of bis(trichloromethyl)carbonate in the bis(trichloromethyl)carbonate solution was changed to 5 g, and the second reaction temperature of the polycondensation reaction was adjusted to 100°C to obtain a white alicyclic polycarbonate product. The results are shown in Table 1. Molecular weight analysis revealed that the alicyclic polycarbonate product had a peak molecular weight of 16,813 and a PDI of 1.5. Fourier transform infrared spectroscopy revealed absorption peaks for C=O and OCO at 1734 cm-1 and 1735 cm-2, respectively. -1 and 1251cm -1 .

[0061] Example 3:

[0062] The preparation and analysis of the alicyclic polycarbonate were the same as in Example 1, except that the amount of the co-catalyst pyridine in the mixed solution was changed to 16 g. As shown in Table 1, the alicyclic polycarbonate product prepared was analyzed by molecular weight determination and had a peak molecular weight of 15,718 and a PDI value of 1.6. Furthermore, Fourier transform infrared spectroscopy analysis revealed that the absorption peaks of C=O and OCO were 1734 cm-1 and 1744 cm-2, respectively. -1 and 1251cm-1.

[0063] Example 4:

[0064] The preparation and analysis of the alicyclic polycarbonate were the same as in Example 1, except that the amount of the organic base catalyst, 4-dimethylaminopyridine (DMAP), in the mixed solution was changed to 0.52 g, and the second reaction temperature of the polycondensation reaction was adjusted to 100°C. As shown in Table 1, the alicyclic polycarbonate product prepared was analyzed by molecular weight determination and had a peak molecular weight of 14,931 and a PDI value of 1.7. Furthermore, Fourier transform infrared spectroscopy analysis revealed that the absorption peaks of C=O and OCO were 1734 cm-1 and 1736 cm-2, respectively. -1 and 1251cm -1 .

[0065] Example 5:

[0066] The preparation and analysis methods of the alicyclic polycarbonate were the same as those in Example 1, except that the 2,2-bis(4-hydroxycyclohexyl)propane content was changed to 0.5 M, and the second reaction temperature of the polycondensation reaction was adjusted to 140°C. As shown in Table 1, the alicyclic polycarbonate product prepared was analyzed by molecular weight determination, with a peak molecular weight of 12,276 and a PDI value of 1.7. Fourier transform infrared spectroscopy analysis revealed that the absorption peaks of C=O and OCO were 1738 cm-1, 1747 cm-2, and 1760 cm-3, respectively. -1 and 1254cm -1 .

[0067] Comparative Example 2:

[0068] The preparation method of alicyclic polycarbonate was the same as that in Example 1, except that the composition of the mixed solution was changed to chloroform as the reaction solvent and triethylamine (Et3N) as the co-catalyst, wherein the content of 2,2-bis(4-hydroxycyclohexyl)propane in the mixed solution was 0.4 M; and the composition of the bis(trichloromethyl)carbonate solution was 5 g of bis(trichloromethyl)carbonate and 50 ml of chloroform; and the second reaction temperature of the polycondensation reaction was adjusted to 60°C. However, no product was precipitated.

[0069] Table 1

[0070]

[0071] HBPA:2,2-bis(4-hydroxycyclohexyl)propane

[0072] BTC:Bis(trichloromethyl)carbonate

[0073] Org-cat: Organic base catalyst

[0074] Co-cat: co-catalyst

[0075] In summary, the present invention utilizes a pre-reaction in the presence of an organic base catalyst and a co-catalyst to increase the solubility of 2,2-bis(4-hydroxycyclohexyl)propane, enabling its efficient participation in the reaction. Combined with the use of bis(trichloromethyl)carbonate as a reactive monomer, the alicyclic polycarbonate of the present invention can be prepared under mild reaction conditions. Furthermore, due to the high reaction selectivity of the present method, the resulting alicyclic polycarbonate exhibits high molecular weight and purity, meeting the requirements for use in food containers, optical, and medical products, thereby increasing its application value.

[0076] The above embodiments are intended to be illustrative only and are not intended to limit the present invention. Any person skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention is defined by the appended claims. Any claims that do not affect the effectiveness and purpose of the present invention shall be encompassed by this disclosure.

Claims

1. A method for preparing an alicyclic polycarbonate, comprising: In the presence of a first solvent, an organic base catalyst, and a co-catalyst, dissolving 2,2-bis(4-hydroxycyclohexyl)propane to form a mixed solution, wherein the content of 2,2-bis(4-hydroxycyclohexyl)propane in the mixed solution is 0.5 to 1.0 volume molar concentration; and adding bis(trichloromethyl)carbonate dissolved in a second solvent to the mixed solution for polycondensation to obtain an alicyclic polycarbonate having a peak molecular weight greater than 12,000; The organic base catalyst is selected from at least one of the group consisting of triethylamine, pyridine, 3-methylpiperidine, 4-methylpiperidine and 4-dimethylaminopyridine, the co-catalyst is triethylamine or pyridine, and the organic base catalyst is different from the co-catalyst. 2 . The preparation method according to claim 1 , wherein the polydispersity index of the prepared alicyclic polycarbonate is 1.7 or less. 3 . The preparation method according to claim 1 , wherein the first solvent is one selected from the group consisting of toluene, dichloromethane, chloroform, chlorobenzene, adiponitrile, 2,6-dichlorotoluene, tetrahydrofuran and pyridine. The preparation method according to claim 1 , wherein the second solvent is one selected from the group consisting of toluene, dichloromethane, chloroform, chlorobenzene, adiponitrile, 2,6-dichlorotoluene, tetrahydrofuran and pyridine.

5. The preparation method according to claim 1, wherein the organic base catalyst is 4-dimethylaminopyridine, and the molar ratio of the 4-dimethylaminopyridine to the bis(trichloromethyl)carbonate is 0.01:1 to 0.3:

1. The preparation method according to claim 1 , wherein the co-catalyst is pyridine, and the molar ratio of the pyridine to the bis(trichloromethyl)carbonate is 2:1 to 18:

1.

7. The preparation method according to claim 1, wherein the feed rate of the bis(trichloromethyl)carbonate is 0.05 to 0.5 g / min.

8. The preparation method according to claim 1, wherein The molar ratio of the 2,2-bis(4-hydroxycyclohexyl)propane to bis(trichloromethyl)carbonate is 1:1 to 4:

1. The preparation method according to claim 1 , wherein the reaction temperature of the polycondensation reaction is 15 to 180° C.

10. The preparation method according to claim 1, wherein the reaction time of the polycondensation reaction is 4 to 24 hours.

11. The preparation method according to claim 1, wherein the polycondensation reaction temperature is set to a two-stage temperature comprising a first reaction temperature and a second reaction temperature greater than the first reaction temperature, the first reaction temperature is 15 to 60° C., and the reaction time is 1 to 4 hours; the second reaction temperature is 60 to 180° C., and the reaction time is 8 to 15 hours.

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