TW202424044A - Method for preparing ultrahigh molecular weight cycloaliphatic polycarbonate - Google Patents

Abstract

Provides a method for preparing ultrahigh molecular weight cycloaliphatic polycarbonate, comprising: dissolving the isomer mixture of 2,2-bis(4-hydroxycyclohexyl)propane in the presence of the second solvent, organic base catalyst and co-catalyst to form a mixed solution; and adding bis (trichloromethyl) carbonate dissolved in the third solvent to the mixed solution for performing three segments condensation reaction to prepare the cycloaliphatic polycarbonate with a peak molecular weight (Mp) greater than 12,000.

Description

Preparation method of ultra-high molecular weight alicyclic polycarbonate

The present invention relates to a method for preparing polycarbonate, and in particular to a method for preparing ultra-high molecular weight alicyclic polycarbonate.

Polycarbonate (PC) is an engineering plastic with excellent comprehensive properties. 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 equipment, construction materials, electronic computers, automobiles, aerospace and optics. Among them, bisphenol A (BPA) type aromatic polycarbonate is the most common.

However, the aromatic polycarbonate has a benzene ring structure, so the polycarbonate produced cannot withstand ultraviolet light exposure; in addition, the bisphenol A monomer (BPA, 2,2-bis(4-hydroxyphenyl)propane) left by the bisphenol A type aromatic polycarbonate has problems such as interfering with the endocrine system or causing environmental hormones that cause precocious puberty in females. Therefore, the research on developing other monomers to replace bisphenol A has attracted much attention. In particular, hydrogenated bisphenol A (HBPA, 2,2-bis(4-hydroxycyclohexyl)propane) has a structure similar to that of bisphenol A monomer and does not have a benzene ring structure. It is an ideal monomer to replace bisphenol A. However, there is still no specific report on the technology for industrial preparation of alicyclic polycarbonates at home and abroad.

According to the literature, the synthesis methods of alicyclic polycarbonates can be divided into phosgene method and non-phosgene method (e.g., transesterification method). However, the phosgene used in the phosgene method is highly dangerous and difficult to obtain; and the non-phosgene method must be carried out at high temperature and low pressure, and its reaction conditions are more stringent than the phosgene method. In addition, the molecular weight of alicyclic polycarbonates produced by the prior art is relatively low, so it is difficult to replace the application of the original polycarbonate material. In view of this, it is necessary to propose a preparation method for effectively producing high molecular weight alicyclic polycarbonates to solve the problems existing in the above-mentioned prior art.

To solve the above problems, the present invention provides a method for preparing ultra-high molecular weight alicyclic polycarbonate, which comprises: dissolving a mixture of isomers of 2,2-bis(4-hydroxycyclohexyl)propane in the presence of a first solvent, an organic alkali catalyst and a co-catalyst to form a mixed solution, wherein the content of the mixture of isomers 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 to carry out a three-stage polycondensation reaction to obtain an alicyclic polycarbonate with a peak molecular weight (Mp) greater than 12000 g/mol.

In a specific embodiment of the present invention, the polydispersity index (PDI value) of the alicyclic polycarbonate obtained is less than 1.7.

In a specific embodiment of the present invention, the preparation method further includes, before forming the mixed solution, allowing the unpurified 2,2-bis(4-hydroxycyclohexyl)propane to recrystallize in the presence of a composite solvent to form an isomer mixture of the 2,2-bis(4-hydroxycyclohexyl)propane, and then dissolving the isomer mixture of the 2,2-bis(4-hydroxycyclohexyl)propane in the first solvent to form a mixed solution.

In a specific embodiment of the present invention, the composite solvent is a liquid chlorine-containing solvent, and the liquid chlorine-containing compound solvent is at least two solvents selected from the group consisting of dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, hexachlorocyclohexane and chlorobenzene.

In a specific embodiment of the present invention, the liquid chlorine-containing solvent includes chloroform and chlorobenzene, and the molar ratio of the chloroform to the chlorobenzene is 9.9:0.1 to 7:3.

In one embodiment of the present invention, the concentration of the unpurified 2,2-bis(4-hydroxycyclohexyl)propane in the composite solvent is 0.05 to 5 g/ml.

In a specific embodiment of the present invention, the recrystallization includes heating and stirring the composite solvent containing the 2,2-bis(4-hydroxycyclohexyl)propane at 200 to 800 rpm for 1 to 3 hours and 60 to 85°C, preferably 65 to 75°C, until the composite solvent refluxes; leaving the composite solvent for 1 to 8 hours and allowing the composite solvent to cool to room temperature; and filtering the composite solvent cooled to room temperature to separate the filtrate and the isomer mixture of 2,2-bis(4-hydroxycyclohexyl)propane rich in trans-trans isomers.

In a specific embodiment of the present invention, the three-stage polycondensation reaction includes a first stage polycondensation reaction, a second stage polycondensation reaction and a third stage polycondensation reaction in sequence, wherein the first stage polycondensation reaction has a first stirring speed, a first reaction time and a first reaction temperature; the second stage polycondensation reaction has a second stirring speed, a second reaction time and a second reaction temperature; and the third stage polycondensation reaction has a third stirring speed, a third reaction time and a third reaction temperature, wherein the second reaction temperature is greater than the first reaction temperature, and the third reaction temperature is greater than the second reaction temperature.

In a specific embodiment of the present invention, the first reaction temperature is 15 to 30°C, the first reaction time is 1 to 4 hours, and the first stirring speed is 100 to 200 rpm. The second reaction temperature is 30 to 60°C, the second reaction time is 1 to 4 hours, and the second stirring speed is 200 to 400 rpm. The third reaction temperature is 60 to 120°C, the third reaction time is 2 to 15 hours, and the third stirring speed is 400 to 600 rpm.

In a specific embodiment of the present invention, the content of trans-trans isomers in the isomer mixture of 2,2-bis(4-hydroxycyclohexyl)propane is 45 to 99 mol%, and the content of cis-cis isomers is less than 8 mol%.

In a specific embodiment of the present invention, the content of cis-trans isomers in the isomer mixture of 2,2-bis(4-hydroxycyclohexyl)propane is greater than 0 to 7 mol%.

In a specific embodiment of the present invention, the purity of the purified recrystallized 2,2-bis(4-hydroxycyclohexyl)propane is above 99%.

In a specific embodiment of the present invention, the first solvent is selected from one of the group consisting of toluene, dichloromethane, chloroform, chlorobenzene, adiponitrile, 2,6-dichlorotoluene, tetrahydrofuran and pyridine. Preferably, the first solvent is a solvent having a boiling point higher than 60°C and containing chlorine, such as chloroform, chlorobenzene and 2,6-dichlorotoluene. In addition, the second solvent for dissolving bis(trichloromethyl)carbonate is also the same as the first solvent for dissolving 2,2-bis(4-hydroxycyclohexyl)propane. For example, one of the solvents can be selected from the group consisting of toluene, dichloromethane, chloroform, chlorobenzene, adiponitrile, 2,6-dichlorotoluene, tetrahydrofuran and pyridine. In addition, no aqueous solvent is added in the present invention to avoid affecting the reaction.

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). Preferably, 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.

In a specific embodiment, the co-catalyst is triethylamine or pyridine. In the present invention, the co-catalyst is different from the organic base catalyst. If the organic base catalyst is selected from at least one of the group consisting of 3-methylpiperidine, 4-methylpiperidine and 4-dimethylaminopyridine (DMAP), the co-catalyst is triethylamine or pyridine. Specifically, the combination of the catalyst/co-catalyst is selected from one of 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. In a specific embodiment of the present invention, the molar ratio of the co-catalyst to the bis(trichloromethyl)carbonate is 2:1 to 18:1. In a specific embodiment of the present invention, the co-catalyst is pyridine, and the molar ratio of the pyridine to the bis(trichloromethyl)carbonate is 2:1 to 18:1. In other words, the amount of the co-catalyst is greater than that of the organic base catalyst.

In a specific embodiment of the present invention, the second solvent is a solvent selected from the group consisting of toluene, dichloromethane, chloroform, chlorobenzene, adiponitrile, 2,6-dichlorotoluene, tetrahydrofuran and pyridine.

In a specific embodiment of the present invention, the bis(trichloromethyl) carbonate is added to the mixed solution in batches at a temperature range of 5 to 20°C.

In a specific embodiment of the present invention, the bis(trichloromethyl) carbonate is added to the mixed solution in batches at a stirring speed ranging from 10 to 100 rpm.

In a specific embodiment of the present invention, based on the feed amount of 10 g of 2,2-bis(4-hydroxycyclohexyl)propane, the bis(trichloromethyl)carbonate is added to the mixed solution at a feed amount of 0.15 to 0.4 g/min (grams/minute).

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

Specifically, according to the present invention, the solubility of 2,2-bis(4-hydroxycyclohexyl)propane is increased through the use of an organic alkali catalyst and a co-catalyst, so that it can effectively participate in the reaction. In particular, the use of the co-catalyst effectively controls the activity of the organic alkali catalyst, provides immediate reactivity during the subsequent polycondensation, and allows the preparation of the mixed solution at room temperature, which not only eliminates the risk of hydrolysis caused by the precipitation of the reactants, but also facilitates mass production. In addition, the three-stage polycondensation reaction of the present invention is not only easy to operate, but also has a high product purity and a molecular weight of up to 10,000. It can break through the low molecular weight bottleneck of the existing technology and solve the environmental hormonal concerns of bisphenol A in food containers.

In addition, 2,2-bis(4-hydroxycyclohexyl)propane is purified and recrystallized to form an isomer mixture by using a liquid chlorine-containing solvent and a recrystallization method, and the ratio of various isomers can be controlled, for example, the content of cis-cis isomers is less than 8 mol%, and/or the content of trans-trans isomers is 45 to 99 mol%, thereby increasing the molecular weight of polycarbonate.

Since the preparation method of the present invention has high reaction selectivity, the alicyclic polycarbonate produced has the characteristics of high molecular weight and high purity, which meets the use requirements of food containers, optics, and medical products, increasing its application value.

The implementation method of the present disclosure is described through exemplary reference drawings:

Figure 1 is a Fourier transform infrared spectrum diagram 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).

The following describes the implementation of the present invention through specific embodiments. Those skilled in the art can easily understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied in other different embodiments. Various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the spirit of the present invention. In addition, all ranges and values herein are inclusive and combinable. Any value or point that falls within the range described in this article, such as any integer, can be used as a minimum or maximum value to derive a lower range, etc.

The “isomer mixture of 2,2-bis(4-hydroxycyclohexyl)propane” mentioned in the present invention refers to 2,2-bis(4-hydroxycyclohexyl)propane having a cis-cis configuration, 2,2-bis(4-hydroxycyclohexyl)propane having a cis-trans configuration, and 2,2-bis(4-hydroxycyclohexyl)propane having a trans-trans configuration. The cis-cis configuration of 2,2-bis(4-hydroxycyclohexyl)propane is also called "cis-cis isomer", the cis-trans configuration of 2,2-bis(4-hydroxycyclohexyl)propane is also called "cis-trans isomer", and the trans-trans configuration of 2,2-bis(4-hydroxycyclohexyl)propane is also called "trans-trans isomer".

The "trans-trans isomer-rich 2,2-bis(4-hydroxycyclohexyl)propane isomer mixture" mentioned in the present invention refers to a 2,2-bis(4-hydroxycyclohexyl)propane isomer mixture in which the content of trans-trans isomer is greater than 50 mol%, or between 50 and 99 mol%, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 96, 97, 98, 99 mol%.

The "cis-trans isomer-rich 2,2-bis(4-hydroxycyclohexyl)propane isomer mixture" mentioned in the present invention refers to a cis-trans isomer content of the 2,2-bis(4-hydroxycyclohexyl)propane isomer mixture greater than 50 mol%, or between 50 and 99 mol%, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 96, 97, 98, 99 mol%.

According to the present invention, a method for preparing ultra-high molecular weight alicyclic polycarbonate comprises: dissolving the isomer mixture of 2,2-bis(4-hydroxycyclohexyl)propane in the presence of a first solvent, an organic alkali catalyst and a co-catalyst to form a mixed solution, wherein the isomer mixture of 2,2-bis(4-hydroxycyclohexyl)propane has a content of 0.5 to 1.0 volume molar concentration in the mixed solution; and adding bis(trichloromethyl)carbonate dissolved in a second solvent to the mixed solution to carry out a three-stage polycondensation reaction to obtain an alicyclic polycarbonate having the following formula (I), wherein n is greater than 40,

Through the above-mentioned preparation method, the peak molecular weight (Mp) of the prepared alicyclic polycarbonate can be greater than 12000 g/mol; in a specific embodiment, n is 40 to 530, for example, n is 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 350, 400, 450, 500, 510, 520, or 530. In a specific embodiment, the polydispersity index (PDI value) of the prepared alicyclic polycarbonate is less than 1.7.

In the embodiment of the present invention, the reaction device used in the preparation method of the present invention further includes a stirring device, such as a stirring tank reactor. In a specific embodiment, the stirring device can be a spinner 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.

In a specific embodiment of the present invention, the preparation method further includes, before forming the mixed solution, allowing the unpurified 2,2-bis(4-hydroxycyclohexyl)propane to recrystallize in the presence of a composite solvent to form an isomer mixture of the 2,2-bis(4-hydroxycyclohexyl)propane, and then dissolving the isomer mixture of the 2,2-bis(4-hydroxycyclohexyl)propane in the first solvent to form a mixed solution.

In a specific embodiment of the present invention, the composite solvent is a liquid chlorine-containing solvent, and the liquid chlorine-containing compound solvent is at least two solvents selected from the group consisting of dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, hexachlorocyclohexane and chlorobenzene.

In a specific embodiment of the present invention, the liquid chlorine-containing solvent includes chloroform and chlorobenzene, and the molar ratio of the chloroform to the chlorobenzene is 9.9:0.1 to 7:3, preferably 9.5:0.5 to 7.5:2.5. In other embodiments, the molar ratio of the chloroform to the chlorobenzene may be 9.9:0.1, 9.7:0.3, 9.5:0.5, 9.4:0.6, 9.3:0.7, 9.2:0.8, 9.1:0.9, 9:1, 8.9:1.1, 8.8:1.2, 8.7:1.3, 8.6:1.4, 8.5:1.5, 8.4:1.6, 8.3:1.7, 8.2:1.8, 8.1:1.9, 8:2, 7.9:2.1, 7.8:2.2, 7.7:2.3, 7.6:2.4, 7.5:2.5, 7.3:2.7 or 7:3.

In one embodiment of the present invention, the concentration of the unpurified 2,2-bis(4-hydroxycyclohexyl)propane in the composite solvent is 0.05 to 5 g/ml. In other embodiments, the concentration of the unpurified 2,2-bis(4-hydroxycyclohexyl)propane in the composite solvent may be 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.5, 4, 4.5 or 5 g/ml.

In a specific embodiment of the present invention, the recrystallization comprises heating and stirring a composite solvent containing 2,2-bis(4-hydroxycyclohexyl)propane at 60 to 85° C., preferably 65 to 75° C., for 1 to 3 hours at 200 to 800 rpm until the composite solvent refluxes; leaving the composite solvent for 1 to 8 hours and allowing the composite solvent to cool to room temperature; and filtering the composite solvent cooled to room temperature to separate the filtrate and an isomer mixture of 2,2-bis(4-hydroxycyclohexyl)propane enriched in trans-trans isomers. In other embodiments, the 2,2-bis(4-hydroxycyclohexyl)propane in the composite solvent can be purified and recrystallized at a temperature of 60, 65, 70, 75, 80 or 85°C, a time of 1, 1.5, 2, 2.5 or 3 hr, and a stirring speed of 200, 250, 300, 350, 400, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 650, 700, 750 or 800 rpm.

In a specific embodiment of the present invention, the three-stage polycondensation reaction includes a first stage polycondensation reaction, a second stage polycondensation reaction and a third stage polycondensation reaction in sequence, wherein the first stage polycondensation reaction has a first stirring speed, a first reaction time and a first reaction temperature; the second stage polycondensation reaction has a second stirring speed, a second reaction time and a second reaction temperature; and the third stage polycondensation reaction has a third stirring speed, a third reaction time and a third reaction temperature, wherein the second reaction temperature is greater than the first reaction temperature, and the third reaction temperature is greater than the second reaction temperature.

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

In a specific embodiment of the present invention, the first reaction temperature is 15 to 30° C., for example, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30° C., the first reaction time is 1 to 4 hours, for example, 1, 1.5, 2, 2.5, 3, 3.5 or 4 hr, and the first stirring speed is 100 to 200 rpm, for example, 100, 110, 120, 130, 140, 145, 150, 155, 160, 170, 180, 190 or 200 rpm. The second reaction temperature is 30 to 60° C., for example, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58 or 60° C., the second reaction time is 1 to 4 hours, for example, 1, 1.5, 2, 2.5, 3, 3.5 or 4 hr, and the second stirring speed is 200 to 400 rpm, for example, 200, 220, 240, 260, 280, 300, 320, 330, 340, 350, 360, 380 or 400 rpm. The third reaction temperature is 60 to 120°C, for example: 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115 or 120°C, the third reaction time is 2 to 15 hours, for example: 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15 hr, and the third stirring speed is 400 to 600 rpm, for example: 400, 420, 430, 440, 450, 460, 480, 500, 520, 540, 560, 580 or 600 rpm.

In one embodiment of the present invention, the content of the trans-trans isomer in the isomer mixture of 2,2-bis(4-hydroxycyclohexyl)propane is 45 to 99 mol%, for example, 45, 49, 50, 55, 60, 64, 65, 70, 75, 80, 85, 87, 88, 89, 90, 91, 91.5, 92, 92.5, 93, 93.5, 94, 94.5, 95, 95.5, 96, 96.5, 97, 97.5, 98. 8, 98.5 or 99 mol%; the content of cis-trans isomers is 45 mol% or less, for example, greater than 0, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.5, 3, 3.5, 4, 4.5, 5, 10, 20, 30, 32, 40, 44 or 45 mol%; the content of cis-cis isomers is 8 mol% or less, for example, 0, 1, 2, 3, 4, 5, 6 or 7 mol%.

In a specific embodiment of the present invention, the content of cis-trans isomers in the isomeric mixture of 2,2-bis(4-hydroxycyclohexyl)propane is greater than 0 to 7 mol%. For example: 0, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5 or 7 mol%.

In a specific embodiment of the present invention, the purity of the purified recrystallized 2,2-bis(4-hydroxycyclohexyl)propane is above 99%, for example: 99, 99.1, 99.2, 99.3, 99.4, 99.5, 99.6, 99.7, 99.8 or 99.9%.

In a specific embodiment of the present invention, the first solvent is selected from one of the group consisting of toluene, dichloromethane, chloroform, chlorobenzene, adiponitrile, 2,6-dichlorotoluene, tetrahydrofuran and pyridine. Preferably, the first solvent is a solvent having a boiling point higher than 60°C and containing chlorine, such as chloroform, chlorobenzene and 2,6-dichlorotoluene. In addition, the second solvent for dissolving bis(trichloromethyl)carbonate is also the same as the first solvent for dissolving 2,2-bis(4-hydroxycyclohexyl)propane. For example, one of the solvents can be selected from the group consisting of toluene, dichloromethane, chloroform, chlorobenzene, adiponitrile, 2,6-dichlorotoluene, tetrahydrofuran and pyridine. In addition, no aqueous solvent is added in the present invention to avoid affecting the reaction.

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). Preferably, 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. In other embodiments, the molar ratio of the 4-dimethylaminopyridine to the bis(trichloromethyl)carbonate may be 0.05:1, 0.1:1, 0.15:1, 0.2:1 or 0.25:1.

In a specific embodiment, the co-catalyst is triethylamine or pyridine. In the present invention, the co-catalyst is different from the organic base catalyst. If the organic base catalyst is selected from at least one of the group consisting of 3-methylpiperidine, 4-methylpiperidine and 4-dimethylaminopyridine (DMAP), the co-catalyst is triethylamine or pyridine. Specifically, the combination of the catalyst/co-catalyst is selected from one of 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. In a specific embodiment of the present invention, the molar ratio of the co-catalyst to the bis(trichloromethyl)carbonate is 2:1 to 18:1. In a specific embodiment of the present invention, the co-catalyst is pyridine, and the molar ratio of the pyridine to the bis(trichloromethyl)carbonate is 2:1 to 18:1. In other words, the amount of the co-catalyst is greater than that of the organic base catalyst. In other embodiments, the molar ratio of the co-catalyst to the 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.

In a specific embodiment of the present invention, the second solvent is a solvent selected from the group consisting of toluene, dichloromethane, chloroform, chlorobenzene, adiponitrile, 2,6-dichlorotoluene, tetrahydrofuran and pyridine.

In a specific embodiment of the present invention, the bis(trichloromethyl) carbonate is added to the mixed solution in batches at a temperature range of 5 to 20°C.

In a specific embodiment of the present invention, the bis(trichloromethyl) carbonate is added to the mixed solution in batches at a stirring speed ranging from 10 to 100 rpm.

In a specific embodiment of the present invention, based on the feed amount of 2,2-bis(4-hydroxycyclohexyl)propane being 10 g, the bis(trichloromethyl)carbonate is added to the mixed solution at a feed amount of 0.15 to 0.4 g/min (grams/minute).

In a specific embodiment of the present invention, the molar ratio of the 2,2-bis(4-hydroxycyclohexyl)propane to the bis(trichloromethyl)carbonate is 1:1 to 4:1. In other embodiments, the molar ratio of the 2,2-bis(4-hydroxycyclohexyl)propane to the 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.

In the embodiment of the present invention, after the polycondensation reaction, the viscous byproduct formed in the reaction process is an incompletely converted product, which is not conducive to the subsequent application of the reaction product. Therefore, a solvent that does not dissolve the alicyclic polycarbonate of formula (I) and is soluble in the byproduct and unreacted 2,2-bis(4-hydroxycyclohexyl)propane must be selected to precipitate the product of the present invention from the reaction mixture. The solvent that does not dissolve the alicyclic polycarbonate of formula (I) is an alcohol solvent, among which methanol is particularly preferred.

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

Preparation Example 1

100g of 2,2-bis(4-hydroxycyclohexyl)propane (HBPA) (purchased from CPDC) containing 15% cis-cis, 53% cis-trans and 32% trans-trans, 810ml of chloroform and 90ml of chlorobenzene were placed in a 2L three-neck flask equipped with a mechanical stirrer, a condenser and a feeding funnel to form a mixed solution.

Next, the mixed solution was stirred at room temperature at 400 rpm, then heated to reflux for 2 hours at 75°C and cooled to room temperature. It was left at room temperature for 4 hours, filtered under reduced pressure, and 29 g of filter cake was obtained to obtain a purified recrystallized 2,2-bis(4-hydroxycyclohexyl)propane isomer mixture product.

The prepared 2,2-bis(4-hydroxycyclohexyl)propane isomer mixture product was analyzed using a capillary gas chromatograph (GC, Shimadzu GC-2010 Plus), and its purity, melting point, and the content ratio of cis-cis isomer, cis-trans isomer, and trans-trans isomer in the isomer mixture were measured, and the results were recorded in Table 1. The content ratio of cis-cis isomer, cis-trans isomer, and trans-trans isomer in the isomer mixture of Preparation Example 1 was 0:5:95.

Preparation Example 2

100 g of 2,2-bis(4-hydroxycyclohexyl)propane (HBPA) (purchased from Wako) containing 7% cis-cis, 44% cis-trans and 49% trans-trans, 810 ml of chloroform and 90 ml of chlorobenzene were placed in a 2 L three-neck flask equipped with a mechanical stirrer, a condenser and a feeding funnel to form a mixed solution. Next, the mixed solution was stirred at room temperature with the stirring speed set to 400 rpm, then heated to reflux for 2 hours and 75°C and cooled to room temperature, and then allowed to stand at room temperature for 4 hours. After reduced pressure filtration, 45 g of the filter cake was obtained to obtain a purified recrystallized 2,2-bis(4-hydroxycyclohexyl)propane product, the analysis method of which was the same as that of Preparation Example 1. The content ratio of cis-cis isomer, cis-trans isomer and trans-trans isomer in the isomer mixture of Preparation Example 2 was 0:2:98.

Embodiment 1

HBPA purchased from Wako was used, and the ratio of cis-cis isomer, cis-trans isomer and trans-trans isomer in its isomer mixture was 7:44:49.

10g of the above HBPA, 25ml of the reaction solvent chlorobenzene, 9.32g of the co-catalyst (Co-cat) pyridine and 0.26g 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, 1atm), wherein the content of 2,2-bis(4-hydroxycyclohexyl)propane in the mixed solution was 0.95M.

Then, the dropping and stirring process is performed. The temperature is adjusted to 10°C, and 10g of bis(trichloromethyl) carbonate (BTC) is dissolved in 20ml of chlorobenzene to prepare a bis(trichloromethyl) carbonate solution. The bis(trichloromethyl) carbonate solution is slowly dropped into the mixed solution from a dropping funnel at a dropping temperature of 10°C and a stirring speed of 50 rpm for 30 minutes at a dropping speed of 0.2g/min to perform a three-stage polycondensation reaction for 12 hours. The three-stage polycondensation reaction includes The three-stage setting includes reaction temperature, reaction time and stirring speed. The setting conditions of the first stage polycondensation reaction are: polymerization temperature 30°C, stirring speed 180rpm, polymerization time 2 hours; the setting conditions of the second stage polycondensation reaction are: polymerization temperature 50°C, stirring speed 340rpm, polymerization time 2 hours; the setting conditions of the third stage polycondensation reaction are: polymerization temperature 120°C, stirring speed 420rpm, polymerization time 8 hours. After the three-stage polycondensation reaction is completed, methanol is added to the above reaction solution. After vacuuming, filtering and drying, a white alicyclic polycarbonate (HPC) product is obtained.

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

(i) Fourier transform infrared spectroscopy analysis: The reactant 2,2-bis(4-hydroxycyclohexyl)propane (HBPA) and the alicyclic polycarbonate (HPC) product prepared above were prepared as powder samples, respectively, and analyzed using a Fourier transform infrared spectrometer (PerkinElmer, Spectrum Two) in the wave number range of 400 to 4000 cm ^-1 . The measured results are recorded in Figure 1.

(II) Molecular weight determination: The peak molecular weight (Mp) of the product was detected using a gel permeation chromatograph (GPC, Waters, 1515 System), where 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.

The results are shown in Table 1. After the above analysis, the peak molecular weight (Mp) of the product was 37,351, the PDI value was 1.5, and in the Fourier transform infrared spectrum analysis, the absorption peak of OH of the reactant HBPA was 3305cm ^-1 ; the absorption peaks of C=O and OCO of the HPC product were 1734cm ^-1 and 1251cm ^-1 respectively.

Embodiment 2

The preparation and analysis methods of HPC are the same as those of Example 1, except that the HBPA used in Example 1 is HBPA purchased from Chemiway, and the content ratio of cis-cis isomer, cis-trans isomer and trans-trans isomer in the isomer mixture is 4:32:64, so as to obtain a white HPC product. The results are shown in Table 1. After the above analysis, the peak molecular weight (Mp) of the prepared HPC product is 57,293, the PDI value is 1.5, and in the Fourier transform infrared spectroscopy analysis, the absorption peaks of C=O and OCO are 1734cm ^-1 and 1251cm ^-1 respectively.

Embodiment 3

The preparation and analysis methods of HPC are the same as those of Example 1, except that the HBPA used in Example 1 is the purified recrystallized HBPA prepared in Preparation Example 1 to obtain a white HPC product. The results are shown in Table 1. After the above analysis, the peak molecular weight (Mp) of the prepared HPC product is 103,481, the PDI value is 1.5, and in the Fourier transform infrared spectrum analysis, the absorption peaks of C=O and OCO are 1734cm ^-1 and 1251cm ^-1 respectively.

Embodiment 4

The preparation and analysis methods of HPC are the same as those of Example 1, except that the HBPA used in Example 1 is changed to the purified recrystallized HBPA prepared in Preparation Example 2 to obtain a white HPC product. The results are shown in Table 1. After the above analysis, the peak molecular weight (Mp) of the prepared HPC product is 119,626, the PDI value is 1.4, and in the Fourier transform infrared spectrum analysis, the absorption peaks of C=O and OCO are 1734cm ^-1 and 1251cm ^-1 respectively.

Embodiment 5

2g of the powdered HPC product of Example 4 was dissolved in chloroform at 80°C to form a thin film after the solvent evaporated. The displacement strain, fracture stress, fracture load and light transmittance of the produced thin plastic were analyzed according to the test methods of ASTM-D882 and ASTM-D1003, and the results are recorded in Table 2.

Comparison Example 1

The preparation and analysis methods of HPC are the same as those in Example 1, except that the three-stage polycondensation reaction is changed to a non-stage polycondensation reaction to obtain a white HPC product. The reaction time of the non-stage polycondensation reaction is 12 hours, the reaction temperature is 120°C, and the stirring speed is 550rpm.

Comparison Example 2

The preparation and analysis methods of HPC are the same as those in Example 2, except that the three-stage polycondensation reaction is changed to a non-stage polycondensation reaction to obtain a white HPC product. The reaction time of the non-stage polycondensation reaction is 12 hours, the reaction temperature is 120°C, and the stirring speed is 550rpm.

Comparison Example 3

Using the same testing method as in Example 5, General PC WONDERLITE ^® Characteristics PC-110 polycarbonate (PC) was made into a transparent film, and the displacement strain, rupture stress, rupture load and transmittance of the produced thin plastic were analyzed. The results are recorded in Table 2.

As shown in Table 1, compared with the alicyclic polycarbonate prepared by non-three-stage condensation reaction in Comparative Examples 1 and 2, the alicyclic polycarbonate prepared by three-stage condensation reaction in Examples 1 to 4 of the present invention has a significantly improved peak molecular weight (Mp). In addition, 2,2-bis(4-hydroxycyclohexyl)propane in Examples 3 and 4 of the present invention, by using a three-stage condensation reaction and containing, for example, greater than 0 to 7 mol% of cis-trans isomers, makes the prepared alicyclic polycarbonate have a peak molecular weight (Mp) greater than 65,000 g/mol.

As shown in Table 2, compared with the film made of general polycarbonate in Comparative Example 3, the film made of ultra-high molecular weight alicyclic polycarbonate in Example 5 of the present invention has better mechanical properties and light transmittance.

In summary, the present invention performs 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 so that it can effectively participate in the reaction, and combined with the use of the reaction monomer bis(trichloromethyl)carbonate, the alicyclic polycarbonate of the present invention can be prepared under mild reaction conditions, which not only avoids the risk of hydrolysis caused by the precipitation of reactants, but also facilitates mass production. In addition, the three-stage polycondensation reaction of the present invention is not only easy to operate, but also has a high product purity and a molecular weight of up to 10,000, which can break through the low molecular weight bottleneck of the existing technology and solve the environmental hormonal concerns of bisphenol A in food containers.

In addition, the present invention purifies and recrystallizes 2,2-bis(4-hydroxycyclohexyl)propane using a chlorine-containing solvent and the reaction conditions of a recrystallization method to form an isomer mixture comprising at least two members selected from the group consisting of cis-cis isomers, cis-trans isomers, and trans-trans isomers, and the composition and ratio of the isomers can be adjusted, for example, the content of cis-cis isomers is less than 8 mol%, the content of cis-trans isomers is less than 45 mol%, and/or the content of trans-trans isomers is 45 to 99 mol%, thereby increasing the molecular weight of the polycarbonate. Therefore, the preparation method of the present invention enables the produced alicyclic polycarbonate to have the characteristics of high molecular weight and high purity, which meets the use requirements of food containers, optics, and medical products, and increases its application value.

The above embodiments are only illustrative and not intended to limit the present invention. Anyone familiar with this technology may modify and change the above embodiments without violating the spirit and scope of the present invention. Therefore, the scope of protection of the present invention is defined by the scope of the patent application attached to the present invention. As long as it does not affect the effect and implementation purpose of the present invention, it should be covered by this public technical content.

Claims (19)

A method for preparing ultra-high molecular weight alicyclic polycarbonate comprises: In the presence of a first solvent, an organic base catalyst and a co-catalyst, a mixture of isomers of 2,2-bis(4-hydroxycyclohexyl)propane is dissolved to form a mixed solution, and the content of the mixture of isomers of 2,2-bis(4-hydroxycyclohexyl)propane in the mixed solution is 0.5 to 1.0 volume molar concentration; and Bis(trichloromethyl)carbonate dissolved in the second solvent is added to the mixed solution to carry out a three-stage polycondensation reaction to obtain a cycloaliphatic polycarbonate with a peak molecular weight (Mp) greater than 12000 g/mol. The preparation method as described in claim 1 further comprises, before forming the mixed solution, allowing the unpurified 2,2-bis(4-hydroxycyclohexyl)propane to recrystallize in the presence of a complex solvent to form an isomer mixture of the 2,2-bis(4-hydroxycyclohexyl)propane. The preparation method as described in claim 2, wherein the composite solvent is a liquid chlorine-containing solvent, and the liquid chlorine-containing solvent is at least two solvents selected from the group consisting of dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, hexachlorocyclohexane and chlorobenzene. The preparation method as described in claim 3, wherein the composite solvent is a liquid chlorine-containing solvent, the liquid chlorine-containing solvent includes chloroform and chlorobenzene, and the molar ratio of the chloroform to the chlorobenzene is 9.9:0.1 to 7:3. The preparation method as described in claim 2, wherein the concentration of the unpurified 2,2-bis(4-hydroxycyclohexyl)propane in the composite solvent is 0.05 to 5 g/ml. The preparation method as described in claim 2, wherein the recrystallization comprises heating and stirring a composite solvent containing the 2,2-bis(4-hydroxycyclohexyl)propane at 200 to 800 rpm until the composite solvent refluxes; leaving the composite solvent for 1 to 8 hours and allowing the composite solvent to cool to room temperature; and filtering the composite solvent cooled to room temperature to separate the filtrate and the isomer mixture of 2,2-bis(4-hydroxycyclohexyl)propane rich in trans-trans isomers. The preparation method as described in claim 1, wherein the three-stage polycondensation reaction includes a first polycondensation reaction, a second polycondensation reaction and a third polycondensation reaction in sequence, wherein the first polycondensation reaction has a first stirring speed, a first reaction time and a first reaction temperature; the second polycondensation reaction has a second stirring speed, a second reaction time and a second reaction temperature; and the third polycondensation reaction has a third stirring speed, a third reaction time and a third reaction temperature, wherein the second reaction temperature is greater than the first reaction temperature, and the third reaction temperature is greater than the second reaction temperature. The preparation method as described in claim 7, wherein the first reaction temperature is 15 to 30°C, the first reaction time is 1 to 4 hours, and the first stirring speed is 100 to 200 rpm. The preparation method as described in claim 7, wherein the second reaction temperature is 30 to 60°C, the second reaction time is 1 to 4 hours, and the second stirring speed is 200 to 400 rpm. The preparation method as described in claim 7, wherein the third reaction temperature is 60 to 120°C, the third reaction time is 2 to 15 hours, and the third stirring speed is 400 to 600 rpm. The preparation method as described in claim 1, wherein the content of the trans-trans isomer in the isomer mixture of 2,2-bis(4-hydroxycyclohexyl)propane is 45 to 99 mol%, and the content of the cis-trans isomer is less than 45 mol%. The preparation method as described in claim 1, wherein the content of cis-trans isomers in the isomer mixture of 2,2-bis(4-hydroxycyclohexyl)propane is greater than 0 to 7 mol%. The preparation method as described in claim 1, wherein the first solvent is one of the solvents selected from the group consisting of toluene, dichloromethane, chloroform, chlorobenzene, adiponitrile, 2,6-dichlorotoluene, tetrahydrofuran and pyridine. The preparation method as described in 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 as described in 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. The preparation method as described in claim 1, wherein the second solvent is one of the solvents selected from the group consisting of toluene, dichloromethane, chloroform, chlorobenzene, adiponitrile, 2,6-dichlorotoluene, tetrahydrofuran and pyridine. The preparation method as described in claim 1, wherein the bis(trichloromethyl) carbonate is added dropwise to the mixed solution at a temperature range of 5 to 20°C and a stirring speed range of 10 to 100 rpm. The preparation method as described in claim 17, wherein, based on the feed amount of 2,2-bis(4-hydroxycyclohexyl)propane being 10 g, the bis(trichloromethyl)carbonate is added to the mixed solution at a feed amount of 0.15 to 0.4 g/min. The preparation method as described in claim 1, wherein the molar ratio of the 2,2-bis(4-hydroxycyclohexyl)propane to the bis(trichloromethyl)carbonate is 1:1 to 4:1.