Polycarbonate prepared by using catalyst to activate carbon dioxide and preparation method thereof
By activating carbon dioxide with cyclopropylene imine catalysts, polycarbonate is prepared, and the problem of using highly toxic phosgene and expensive ionic liquids in the prior art is solved, and a safe, environmentally friendly and cost-effective polycarbonate synthesis is achieved.
Patent Information
- Application Number
- CN202311657507.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-11-30
- Filing Date
- 2023-12-05
- Publication Date
- 2025-05-30
AI Technical Summary
In the existing polycarbonate synthesis technology, most methods require the use of highly toxic phosgene or expensive ionic liquids, which have safety and cost problems.
Carbon dioxide is activated by cyclopropylene imine catalysts, carbonation is performed under mild temperature and pressure to prepare polycarbonate.
It realizes efficient conversion of CO2 into polymer without using highly toxic phosgene, which is simple, safe and environmentally friendly, reducing production costs.
Smart Images
Figure BDA0004589332470000021 
Figure BDA0004589332470000022 
Figure BDA0004589332470000031
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of polycarbonate and its preparation, and specifically to a polycarbonate prepared by activating carbon dioxide using a cyclopropenimine catalyst and a preparation method thereof. Background Art
[0002] At present, the synthesis technologies of polycarbonate mainly include phosgene interfacial polycondensation method, melt transesterification polycondensation method and non-phosgene melt transesterification polycondensation method. The first two methods both need to use highly toxic phosgene. The non-phosgene melt transesterification method was developed by Asahi Kasei Corporation of Japan on the basis of the melt transesterification method. Using dimethyl carbonate as a raw material, reacting with phenol to obtain diphenyl carbonate, and performing transesterification and polycondensation with bisphenol A in the molten state to prepare polycarbonate. Although this process is relatively complex, it does not use toxic phosgene and effectively utilizes CO 2 , belonging to the "green chemistry" clean production process, which is the future development direction for preparing polycarbonate.
[0003] The Institute of Process Engineering, Chinese Academy of Sciences also proposed a method for preparing polycarbonate from CO 2 . However, it uses highly toxic double metal cyanide as the main catalyst and expensive ionic liquid as a medium, which brings adverse factors to the cost and safety of industrialization. Summary of the Invention
[0004] The purpose of the present invention is to provide a polycarbonate prepared by activating carbon dioxide using a catalyst based on the above-mentioned existing technologies.
[0005] The second purpose of the present invention is to provide a method for preparing the polycarbonate by activating carbon dioxide using a catalyst.
[0006] The present invention aims to use an organic non-metallic compound cyclopropenimine catalyst (collectively referred to as "high catalyst") to activate CO 2 under mild temperature and pressure, and perform carbonation addition to prepare polycarbonate, so that CO 2 can be effectively converted into a polymer.
[0007] To achieve the above invention purposes, the technical solution adopted by the present invention is: a polycarbonate prepared by activating carbon dioxide using a catalyst, under mild temperature of 5 - 100 °C and pressure of 0.1 - 5 bar, HO-R A -OH and X-R B -X are prepared by carbonation addition under the activation of a cyclopropenimine catalyst (collectively referred to as "high catalyst") for CO 2 . The preparation reaction equation is as follows:
[0008]
[0009] Wherein, X is a halogen, and the O of two hydroxyl groups (OH) and two halogens (X) are respectively connected to the terminal carbon atoms on R A and R B respectively. R A and R B may be the same or different. R A and R B may be straight-chain or branched-chain alkyl groups with various carbon numbers, and the number of carbon atoms is between 1 and 20; the groups on the carbon chain and / or the branched chain of R A and R B may contain unsaturated bonds and various functional groups, including -OH, -NH-, -N=, -O-, -S-, -Si-, -Si-O-, -(C=O)-, -C≡N, aromatic cluster groups, cyclic non-aromatic cluster groups, etc.; n is a natural number greater than 10, and preferably, n is a natural number between 100 and 1000;
[0010] The chemical structural formula of the cyclopropenimine-based catalyst (hereinafter referred to as "high catalyst") is:
[0011]
[0012] Wherein, the number of carbon atoms on the carbon chain of R A* and R B* is 1 to 20, and preferably, the number of carbon atoms on the carbon chain of the said R A* is within 10 carbon atoms, and the number of carbon atoms on the carbon chain of R B* is within 7 carbon atoms; R A* and R B* are organic groups connected to N. R A* and R B* may be the same or different. The carbon chain and the branched chain of R A* and R B* may contain unsaturated bonds and various functional groups, including -OH, -NH-, -N=, -O-, -S-, -Si-, -Si-O-, -(C=O)-, -C≡N, aromatic cluster groups, cyclic non-aromatic cluster groups, etc.
[0013] The performance of the cyclopropenimine-based catalyst (high catalyst) can be adjusted by the selection of R A* and R B* .
[0014] A preparation method for preparing polycarbonate by activating carbon dioxide using a catalyst, which includes the following steps: First, add the cyclopropenimine-based catalyst and a solvent into a reaction kettle, and under turbulent stirring, introduce CO 2 gas to displace the oxygen in the reaction kettle; then close the exhaust port of the reaction kettle and continue to introduce CO 2, and control the temperature and pressure of the reactor at the given values, then add HO-R A -OH to carry out the first-stage reaction; after the first-stage reaction is completed, slowly add X-R B -X to carry out the second-stage reaction to complete the synthesis of polycarbonate.
[0015] The temperature of the reactor is set between 5 - 100 °C, preferably between 10 - 60 °C.
[0016] The pressure of the reactor is the pressure of CO 2 The gauge pressure of the gas pressure setting is between 0.1 - 5.0 bar. Preferably, the pressure of the reactor is between 0.1 - 1.2 bar. More preferably, the pressure of the reactor is between 0.3 - 1.0 bar.
[0017] The solvent is a solvent that can dissolve the cyclopropeneimine catalyst, HO-R A -OH, X-R B -X and the synthesized polycarbonate, but does not dissolve the high-catalytic halide.
[0018] The time of the first reaction stage depends on the structure of the cyclopropeneimine catalyst, the solvent and R A , usually requires 0 - 4 hours, preferably, in most cases, within 1 hour. The time of the second-stage reaction depends on the structure of the cyclopropeneimine catalyst, the solvent, R A and R B , as well as the reaction temperature and pressure, usually requires 1 - 12 hours. Preferably, in most cases, within 7 hours.
[0019] A polycarbonate is prepared by using benzonitrile as a solvent, 1,4-cyclohexanedimethanol and 1,4-bis(bromomethyl)benzene under mild temperature and pressure, and activating CO 2 for carbonation addition copolymerization. The preparation reaction equation is as follows:
[0020]
[0021] Among them, n is a natural number greater than 10, preferably, n is a natural number between 100 - 1000.
[0022] A silicon-containing copolymer flame-retardant polycarbonate is prepared by using benzonitrile as a solvent, chloro-terminated poly(dimethylsiloxane) and terephthalic alcohol under mild temperature and pressure, and activating CO 2 for carbonation addition copolymerization. The preparation reaction equation is as follows:
[0023]
[0024] Among them, the length n of the silicon-oxygen chain can be used to adjust the silicon-oxygen content in the polycarbonate to achieve desired mechanical properties, flame retardant effect, low-temperature resistance, etc. n is 0 or a natural number greater than 0. Preferably, n is between 2 and 10. m is a natural number greater than 10. Preferably, m is a natural number between 50 and 500.
[0025] The present invention uses a cyclopropenimine catalyst (collectively referred to as "high catalyst") to activate CO under mild temperature and pressure 2 for carbonation addition to prepare polycarbonate, so that CO 2 is effectively converted into a polymer. In the process of synthesizing polycarbonate, not only is the process simple, but also the use of CO 2 avoids the use of highly toxic phosgene. Not only is CO effectively converted into advanced materials, contributing to the realization of "carbon peak and carbon neutrality", but also it is a safe and environmentally friendly technology. 2
[0026] Compared with the prior art, the beneficial effects of the present application are: highly toxic phosgene raw materials are not used in the preparation process, the reaction process is simple, the process flow is short, and it is safe and environmentally friendly. Specific Embodiments
[0027] In order to make the purpose and advantages of the present invention clearer, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention; all possibilities covered by the claims of the present invention, including all alternative solutions, improvement solutions, and equivalent solutions.
[0028] Example 1
[0029] This example is for the high catalyst to activate CO 2 to prepare polycarbonate, and the steps included are as follows: In a 2-liter glass reaction kettle with a jacket, a stirring system is installed; the stirring system includes a pair of glass baffles with a diameter of 1.5 cm and a stainless steel pitched-blade turbine stirrer with a diameter of 4 cm. A thermometer is installed in one of the baffles. There are a feed inlet and an exhaust port above the reaction kettle, and a discharge port below; in the reaction kettle, 200 g of high catalyst (((R A 2 N) 2 C 3 (NRB)) (molecular weight 335), where R A is n-butyl and RB is ethyl) and 900 g of the solvent phenylacetonitrile are added. The temperature of the reaction kettle is controlled and set at 55 °C, and stirring is started. The stirring rate ensures that the Reynolds number based on the stirrer diameter and water is 20,000. First, CO 2 gas is introduced from above the reaction kettle for 5 minutes and then discharged. Subsequently, the exhaust port is closed, and CO is continuously introduced2 and control the pressure of the reactor (table) at 0.5 bar, add 43 g of 1,4-cyclohexanedimethanol (molecular weight 144.21), and react for 1 hour. Then slowly dropwise add 78.8 g of 1,4-bis(bromomethyl)benzene (molecular weight 263.96) dissolved in phenylacetonitrile, and the reaction time is 6 - 10 hours to prepare polycarbonate. The preparation reaction equation is as follows:
[0030]
[0031] In the reaction process, high catalyst gets Br - and H + ions to form high catalyst bromide, which is insoluble in phenylacetonitrile and dispersed in the liquid phase in solid form. Therefore, after the reaction, control the temperature at the reaction temperature (55 °C), filter and separate the solid high catalyst bromide. The liquid phase is returned to the reactor, and cooled with stirring until the prepared polycarbonate precipitates from phenylacetonitrile in solid form. The reaction analysis results are shown in Table 1 below.
[0032] Table 1 Influence of reaction time on the yield and molecular weight of polycarbonate described by the above reaction formula
[0033]
[0034] Return the separated solid high catalyst bromide to the original reactor, add 900 g of phenylacetonitrile and 300 mL of 2 M NaOH aqueous solution, stir slowly, carry out a neutralization reaction to reduce the high catalyst, and extract the reduced high catalyst back into phenylacetonitrile. Separate the organic phase from the aqueous phase, and let the organic phase pass through a solid drying column to remove residual moisture, obtaining the high catalyst dissolved in phenylacetonitrile for recycling.
[0035] Example 2
[0036] This example is for high catalyst to activate CO 2 to prepare a silicon-containing flame-retardant polycarbonate, and the steps included are as follows: In the reactor with a stirring system used in Example 1, add 200 g of high catalyst (((R A 2 N) 2 C 3 (NR B )) (molecular weight 349), where R A is n-butyl, R B is propyl), and 900 g of the solvent phenylacetonitrile. Control the temperature of the reactor at 55 °C and start stirring. The stirring rate ensures that the Reynolds number based on the stirrer diameter and water is 30000. First, introduce CO 2 gas from above the reactor for 5 minutes and evacuate. Subsequently, close the exhaust port and continue to introduce CO 2, and control the pressure of the reactor (table) at 0.5 bar, add 39.6 grams of p-benzenedimethanol (molecular weight 138.16), and react for 1 hour. Then slowly add dropwise 100.7 grams of poly(dimethylsiloxane) with a molecular weight of 351.3 or 143.1 grams of poly(dimethylsiloxane) with a molecular weight of 499.5 dissolved in benzonitrile, and react for 10 hours to prepare a silicon-containing copolymer flame-retardant polycarbonate. The reaction equation for the preparation is as follows:
[0037]
[0038] Among them, the length n of the silicon-oxygen chain is 2 or 4 respectively. During the reaction, high catalyst produces Cl - and H + ions to form high-catalyst chloride, which is insoluble in benzonitrile and is dispersed in the liquid phase in solid form. Therefore, after the reaction, control the temperature at the reaction temperature (55 °C) to filter and separate the solid high-catalyst chloride. The liquid phase is returned to the reactor, and it is cooled with stirring until the produced polycarbonate precipitates from benzonitrile in solid form. The reaction analysis results are listed in Table 2.
[0039] Table 2 Yield and molecular weight of the prepared silicon-containing flame-retardant polycarbonate:
[0040] Degree of polymerization n of the poly(dimethylsiloxane) siloxane chain 2 4 Yield of the silicone-containing polycarbonate 96.5％ 95.8％ Molecular weight (kDa) of the silicone-containing polycarbonate ＞100 ＞100
[0041] Return the separated solid high-catalyst chloride to the original reactor, add 900 grams of benzonitrile and 290 milliliters of 2M NaOH aqueous solution, stir slowly, carry out a neutralization reaction to reduce the high catalyst, and extract the generated high catalyst back into benzonitrile. Separate the organic phase from the aqueous phase, and let the organic phase pass through a solid drying column to remove the residual moisture. The obtained high catalyst dissolved in benzonitrile is recycled.
[0042] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.
Claims
1. A polycarbonate prepared by activating carbon dioxide using a catalyst, characterized in that, Under the conditions of temperature ranging from 5 to 100 °C and pressure ranging from 0.1 to 5 bar, HO-R A -OH and X-R B -X are used to prepare by carbonation addition of activated CO 2 under the catalysis of cyclopropenimine catalysts. The preparation reaction equation is as follows: wherein, X is a halogen, R A and R B are linear or branched alkyl groups, and R A and R B contain unsaturated bonds and / or -OH, -NH-, -N=, -O-, -S-, -Si-, -Si-O-, -(C=O)-, -C≡N, aromatic cluster groups, cyclic non-aromatic cluster groups on the carbon chain and / or side chain; the chemical structure of the cycloalkenimine catalyst is: Among them, R A* and R B* have 1 to 20 carbon atoms in the carbon chain, and R A* and R B* contain unsaturated bonds, -OH, -NH-, -N=, -O-, -S-, -Si-, -Si-O-, -(C=O)-, -C≡N, aromatic cluster groups, and cyclic non-aromatic cluster groups in the carbon chain and side chain.
2. The polycarbonate prepared by activating carbon dioxide using a catalyst according to claim 1, characterized in that, The R A* has no more than 10 carbon atoms in its carbon chain, and R B* has no more than 7 carbon atoms in its carbon chain.
3. The preparation method of the polycarbonate prepared by activating carbon dioxide using a catalyst according to claim 1, characterized in that: The steps included are as follows: First, add the cyclopropenimine catalyst and the solvent into the reaction kettle, and introduce CO 2 to displace the oxygen in the reaction kettle; subsequently, seal the exhaust port of the reaction kettle, and continue to introduce CO 2 , and add HO-R A -OH to carry out the first-stage reaction; after the first-stage reaction is completed, add X-R B -X to carry out the second-stage reaction.
4. The preparation method of the polycarbonate prepared by activating carbon dioxide using a catalyst according to claim 3, characterized in that, the temperature of the reaction kettle is set at 10 - 60 °C.
5. The preparation method of the polycarbonate prepared by activating carbon dioxide using a catalyst according to claim 3, characterized in that, the pressure of the reaction kettle is 0.1 - 1.2 bar.
6. The preparation method of the polycarbonate prepared by activating carbon dioxide using a catalyst according to claim 3, characterized in that, the time of the first reaction stage is 0 - 4 hours, and the time of the second reaction stage is 1 - 12 hours.
7. The preparation method of the polycarbonate prepared by activating carbon dioxide using a catalyst according to claim 6, characterized in that, the time of the first reaction stage is within 1 hour; the time of the second reaction stage is within 7 hours.
8. A polycarbonate, characterized in that, Using phenylacetonitrile as a solvent, 1,4-cyclohexanedimethanol and 1,4-bis(bromomethyl)benzene are used, and cyclopropenimine catalysts are used to activate CO 2 The reaction equation for the preparation of carbonation addition copolymerization is as follows: wherein, n is a natural number greater than 10.
9. A silicone-containing copolymer flame-retardant polycarbonate, characterized in that, Using phenylacetonitrile as a solvent, carbonation addition copolymerization is carried out with chlorine-terminated poly(dimethylsiloxane) and terephthalyl alcohol, and CO is activated with a cyclopropenimine catalyst 2 The preparation reaction equation is as follows: wherein, m is a natural number greater than 10, and the length n of the silicon-oxygen chain is 0 or a natural number greater than 0.