Catalyst for catalyzing carbon dioxide cycloaddition reaction and preparation method thereof

Abstract

The invention provides a catalyst for catalyzing a carbon dioxide cycloaddition reaction and a preparation method thereof. The structural formula of the catalyst is # imgabs0 #, polycore is a polystyrene inner core, polyshell is a poly (p-chloromethyl styrene) shell, and Cation N + is a nitrogen-containing cation group; anion O <-> is an anion group containing a phenoloxy group; wherein the structural formula of the anion group containing the phenoloxy group is # imgabs 1 #, and R3 is any one of hydrogen, hydroxyl, methoxyl, amido, nitryl and chlorine. The catalyst is easy to recycle, good in stability and good in catalytic effect.

Description

Technical Field

[0001] The invention belongs to the technical field of carbon dioxide cycloaddition reaction, and particularly relates to a catalyst for catalyzing carbon dioxide cycloaddition reaction and a preparation method thereof. Background Art

[0002] Cyclic carbonates are an important class of chemical products, which have wide applications and prospects in the fields of lithium-ion battery electrolytes, degradable polymer monomers, and organic synthesis intermediates. The industrial synthesis of cyclic carbonates is a cycloaddition reaction of carbon dioxide and epoxides. The existing process uses metal halides and ammonium salts as catalysts, and is prepared under the conditions of a reaction temperature of 100-150°C and a reaction operating pressure of 2.0-5.0MPa. However, both metal halides and ammonium salts contain halogen anions, which cause severe corrosion to metal equipment under high temperature and high pressure reaction conditions, and place high demands on the material of the reactor. In addition, metal halides and ammonium salts are homogeneous catalysts, and catalyst recovery is relatively difficult.

[0003] In view of this, the present invention is proposed. Summary of the invention

[0004] The first object of the present invention is to provide a catalyst for catalyzing the carbon dioxide cycloaddition reaction, which is easy to recover, has good stability and good catalytic effect compared with the existing catalysts for catalyzing the carbon dioxide cycloaddition reaction.

[0005] The second object of the present invention is to provide a method for preparing a catalyst for catalyzing the carbon dioxide cycloaddition reaction, which method can produce a catalyst with good catalytic effect and easy recovery.

[0006] The third object of the present invention is to provide a carbon dioxide cycloaddition reaction method, which uses the above-mentioned catalyst to catalyze the cycloaddition reaction of carbon dioxide gas and epoxy compounds, has high reaction efficiency, and can reduce the demand for carbon dioxide purity, which helps to improve the economy of the cycloaddition reaction.

[0007] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted: The present invention provides a catalyst for catalyzing the carbon dioxide cycloaddition reaction, wherein the structural formula of the catalyst is: , Among them, poly core For the polystyrene core, poly shell For poly(p-chloromethylstyrene) shell, Cation N + is a nitrogen-containing cationic group; Anion O - is a phenoloxy-containing anion group; Wherein, the structural formula of the phenoloxy anion group is: , Wherein, R3 is any one of hydrogen, hydroxyl, methoxy, amino, nitro, and chlorine.

[0008] Compared with the catalyst composed of metal halide and ammonium salt used in the related art, the catalyst provided by the present invention is easy to recover, has good stability and good catalytic effect. This is because the catalyst of the present invention uses polystyrene and poly(p-chloromethylstyrene) as monomers to synthesize a polymer carrier with a core-shell structure, and synthesizes nitrogen-containing cationic groups and phenoloxy-containing anionic groups on the basis of the polymer carrier. Specifically, the polystyrene core layer has a stable mechanical stability. The present invention uses polystyrene as the core to ensure that the catalyst is not easy to break during the reaction process, which helps to recover the catalyst after the reaction is completed. By polymerizing a layer of poly(p-chloromethylstyrene) as an outer shell on the outer layer of polystyrene, the chloromethyl groups contained in the outer shell can be fully utilized to react with a variety of nitrogen-containing compounds to generate nitrogen-containing cationic groups, thereby improving the stability of the grafted nitrogen-containing cationic groups. By grafting nitrogen-containing cationic groups, on the one hand, the amine group of the nitrogen-containing cationic group can be used to absorb CO2 molecules, thereby improving the absorption capacity of the catalyst to CO2 and improving the utilization rate of CO2, and then under the condition of low concentration of carbon dioxide, it can still ensure that the cycloaddition reaction has good reaction selectivity and reaction conversion rate, and is conducive to the catalytic reaction under relatively low pressure conditions. On the other hand, the nitrogen-containing cationic group can be used as a cation to form an ionic bond with the phenoloxy-containing anionic group to realize the immobilization of the phenoloxy-containing anionic group on the surface of the polymer material, thereby further improving the overall structural stability of the catalyst. The immobilized phenoloxy-containing anionic group can activate the CO2 molecule to form an active carbonate, which can effectively reduce the activation energy of the CO2 molecule conversion, which helps to improve the catalytic effect on the cycloaddition reaction, thereby helping to improve the reaction efficiency of the cycloaddition reaction. It can be seen that the scheme of the present invention adopts a specific core, an outer shell and grafts a specific group, so that the obtained catalyst has good catalytic performance, and because of its overall stable structure and simple recovery, the application of the catalyst in the cycloaddition reaction can effectively reduce the cost of the cycloaddition reaction, and help reduce the requirements of the cycloaddition reaction on the reaction conditions (including CO2 gas purity, reaction pressure, etc.), and improve the reaction selectivity and reaction conversion rate of the cycloaddition reaction.

[0009] Preferably, the nitrogen-containing cationic group is any one of the following groups: a sodium hydroxide choline cationic group, a quaternary ammonium cationic group, a guanidine compound cationic group; preferably, the nitrogen-containing cationic group is a guanidine compound cationic group.

[0010] Preferably, the nitrogen-containing cationic group is a sodium hydroxide choline cationic group, and the structural formula of the sodium hydroxide choline cationic group is: .

[0011] Preferably, the nitrogen-containing cationic group is a quaternary ammonium cationic group, and the structural formula of the quaternary ammonium cationic group is: , Where R1 is C 2~4 of alkyl.

[0012] Preferably, the nitrogen-containing cationic group is a guanidine compound cationic group, the guanidine compound cationic group is a guanidinium cationic group, and the structural formula of the guanidinium cationic group is: , Wherein, R2 is methyl or tert-butyl.

[0013] In this scheme, a guanidine cationic group is used as a nitrogen-containing cationic group grafted on the poly(p-chloromethylstyrene) shell. Compared with the sodium hydroxide choline cationic group and the quaternary ammonium cationic group, the guanidine cationic group contains more amine groups. Using it as a nitrogen-containing cationic group can further improve the catalyst's absorption capacity for CO2, thereby further reducing the requirements for the purity of carbon dioxide gas in the cycloaddition reaction.

[0014] Preferably, the guanidine cationic group is 2-methyl-1,1,3,3-tetramethylguanidine, and the structural formula of the 2-methyl-1,1,3,3-tetramethylguanidine is: .

[0015] In the scheme of this embodiment, R2 is a methyl group. The nitrogen-containing cationic group used in this embodiment can further improve the absorption capacity of the catalyst for CO2, so that it can still show good catalytic activity under lower reaction pressure conditions.

[0016] Preferably, the R3 is a nitro group, the phenoloxy-containing anion group is an o-nitrophenol anion group, and the structural formula of the o-nitrophenol anion group is: .

[0017] In the scheme of this embodiment, by making R3 a nitro group, the electron cloud density of the phenol oxide anion can be appropriately reduced, and the nucleophilicity of the phenol oxide anion can be appropriately reduced. The catalyst of this embodiment is applied to the cycloaddition reaction, which can make the carbonate species generated after the activation of CO2 easier to transfer, thereby helping to promote the formation of cyclic carbonates.

[0018] Preferably, the nitrogen-containing cationic group is 2-methyl-1,1,3,3-tetramethylguanidine, the phenoloxy-containing anionic group is an o-nitrophenol anionic group, and the structural formula of the catalyst is: .

[0019] In the scheme of this embodiment, the catalyst uses polystyrene and poly(p-chloromethylstyrene) as monomers to synthesize a polymer carrier with a core-shell structure, and synthesizes nitrogen-containing cationic groups and phenoloxy-containing anionic groups on the basis of the polymer carrier, wherein the nitrogen-containing cationic group is 2-methyl-1,1,3,3-tetramethylguanidine, and the phenoloxy-containing anionic group is an o-nitrophenol anionic group. By adopting this structure, on the one hand, the mechanical stability of the polystyrene core layer can be fully utilized to improve the stability of the catalyst as a whole, so that it can be convenient to recover the catalyst after the reaction is completed, which helps to reduce the reaction cost. On the other hand, the chloromethyl group contained in poly(p-chloromethylstyrene) can be used to load the nitrogen-containing cationic group, which helps to further improve the stability of the catalyst as a whole. On the other hand, the scheme uses 2-methyl-1,1,3,3-tetramethylguanidine as a nitrogen-containing cationic group, and can use the multiple amine groups contained in the nitrogen-containing cationic group to improve the catalyst's absorption capacity for CO2 and improve the utilization rate of CO2, thereby ensuring that the cycloaddition reaction has good reaction selectivity and reaction conversion rate under low concentrations of carbon dioxide, and is conducive to catalytic reaction under relatively low pressure conditions. On the other hand, this scheme can activate CO2 molecules to form active carbonates by using o-nitrophenol anion groups as phenoloxy anion groups, which can effectively reduce the activation energy of CO2 molecule conversion, and the nitro group on the o-nitrophenol anion group can appropriately reduce the electron cloud density of the phenoloxy anion and appropriately reduce the nucleophilicity of the phenoloxy anion, so that the carbonate species generated after the activation of CO2 can be more easily transferred, which helps to improve the reaction selectivity and reaction conversion rate of the cycloaddition reaction. In short, the overall structure of the catalyst of this scheme is stable and easy to recover. The application of this catalyst in the cycloaddition reaction can effectively improve the reaction selectivity and reaction conversion rate of the cycloaddition reaction.

[0020] Preferably, the structural formula of the polystyrene core is: .

[0021] In the scheme of the present invention, the inner core of the catalyst is made of polystyrene, which is relatively cheap and has a good mechanical structure. The preparation cost of the polystyrene inner core is controllable and good structural stability can be ensured.

[0022] Preferably, the structural formula of the poly(p-chloromethylstyrene) shell is: .

[0023] It is understandable that the physical and chemical properties of the polystyrene core itself are very stable, and it is difficult to directly graft other chemical groups thereon. Therefore, in the present invention, by polymerizing a layer of poly(p-chloromethylstyrene) on the outer layer of polystyrene, the shell layer contains a relatively active group such as chloromethyl, which can react with a variety of nitrogen-containing compounds to generate nitrogen-containing cationic groups, thereby improving the stability of the grafted nitrogen-containing cationic groups.

[0024] The present invention also provides a method for preparing the catalyst of the above embodiment, which comprises: dispersing polystyrene microspheres in an organic solvent containing para-chloromethylstyrene monomer; adding an initiator and an emulsifier to the organic solvent to obtain a mixed solution; heating the mixed solution to perform a seed emulsion polymerization reaction to form core-shell microspheres; reacting the core-shell microspheres with a nitrogen-containing cationic compound in anhydrous ethanol to graft nitrogen-containing cationic groups onto the core-shell microspheres; adding a phenoloxy-containing anion compound and the core-shell microspheres into the organic solvent, and stirring the organic solvent to graft the phenoloxy-containing anion groups onto the core-shell microspheres.

[0025] The present invention also provides a carbon dioxide cycloaddition reaction method, which uses the catalyst described in any of the above embodiments, carbon dioxide gas and epoxy compounds as raw materials, and performs a cycloaddition reaction to generate cyclic carbonate.

[0026] Preferably, the amount of the catalyst is 0.05-2wt% of the amount of the epoxy compound. Preferably, the amount of the catalyst is 0.2-1wt% of the amount of the epoxy compound. It is understood that too low a catalyst amount will result in a too slow reaction rate, and too high a catalyst amount will result in agglomeration of catalyst particles in the reaction solution, which will not significantly help to improve the reaction rate and will also greatly increase the production cost. The solution of this embodiment can reduce the waste of catalyst while ensuring the efficiency of the cycloaddition reaction by reasonably selecting the ratio of catalyst to epoxy compound based on the properties of the catalyst itself, which helps to further reduce the production cost.

[0027] Preferably, the purity of the carbon dioxide gas is 20%-99%. It can be understood that in the related art, in order to ensure the reaction efficiency, the purity of the carbon dioxide gas is usually required to be high (for example, more than 60%) when performing the cycloaddition reaction. In the embodiment of the present invention, by adopting a specific catalyst, the absorption capacity of CO2 is improved, and then the utilization rate of CO2 is improved, so that the carbon dioxide gas purity can still be guaranteed when the purity is low. Good reaction efficiency. Therefore, the scheme of the present invention can use carbon dioxide gas with lower purity as the gas source when performing the cycloaddition reaction, which can expand the range of gaseous raw materials used in the cycloaddition reaction and reduce the reaction cost. At the same time, since the carbon dioxide purity of some coal-fired flue gas in the related art can reach 20%, the present invention can directly use coal-fired flue gas as carbon dioxide gas when performing the cycloaddition reaction, which can further reduce the reaction cost of the cycloaddition reaction and has the advantages of being green and environmentally friendly.

[0028] Preferably, the purity of the carbon dioxide gas is 30%-99%. In the scheme of this embodiment, considering that too low purity of carbon dioxide gas may lead to a low gas phase diffusion coefficient, for this reason, carbon dioxide gas with a purity of more than 30% is selected as the gas phase raw material to ensure the reaction efficiency.

[0029] Preferably, the epoxy compound is any one of ethylene oxide, propylene oxide, epichlorohydrin and styrene oxide.

[0030] Preferably, the reaction pressure of the cycloaddition reaction is 0.1-3 MPa. Preferably, the reaction pressure of the cycloaddition reaction is 0.5-2 MPa. As described above, applying the catalyst described in the above embodiment to the cycloaddition reaction can improve the utilization rate of CO2, so when the cycloaddition reaction is carried out, the reaction pressure can be reduced to 0.5-2 MPa, thereby helping to reduce the requirements for the reaction site (which can be called a reactor) of the cycloaddition reaction, thereby helping to reduce the reaction cost.

[0031] Preferably, the reaction temperature of the cycloaddition reaction is in the range of 70-110° C. Preferably, the reaction temperature of the cycloaddition reaction is in the range of 80-100° C.

[0032] Compared with the prior art, the present invention has the following beneficial effects: (1) The catalyst of the present invention has good stability, which can reduce the difficulty of recovering the catalyst after the reaction, thereby helping to reduce the reaction cost; (2) The catalyst of the present invention has good CO2 absorption capacity. Applying the catalyst to the cycloaddition reaction can improve the utilization rate of CO2 and reduce the requirements of the cycloaddition reaction on the reaction conditions, so that the cycloaddition reaction can still ensure good reaction selectivity and reaction conversion rate under the conditions of low concentration of carbon dioxide and low pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings: Figure 1 The infrared spectrum of the catalyst provided in Example 1 of the present invention; Figure 2 This is the electronic energy spectrum of the catalyst provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0034] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but those skilled in the art will understand that the embodiments described below are part of the embodiments of the present invention, rather than all of the embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0035] In order to more clearly explain the technical solution of the present invention, it is described in the form of specific embodiments below.

[0036] Example 1 In this embodiment, the structural formula of the catalyst is: , The chemical formula is PS-TMG-PhNO2. The infrared spectrum of the catalyst can be found in Figure 1 The electronic spectrum of the catalyst is shown in Figure 2 shown.

[0037] The preparation method of the catalyst is as follows: first, 50g of polystyrene microspheres are dispersed in a THF solvent containing a p-chloromethylstyrene monomer, the concentration of the organic solvent is 20%, and the mass of the p-chloromethylstyrene monomer contained is 50g. Then, 0.2g of initiator AIBN and 1g of emulsifier SDS are added to the organic solvent to obtain a mixed solution; the mixed solution is heated to 55°C to perform a seed emulsion polymerization reaction to form core-shell microspheres; the core-shell microspheres are reacted with 10g of 2-methyl-1,1,3,3-tetramethylguanidine compound in anhydrous ethanol to graft nitrogen-containing cationic groups on the core-shell microspheres; 10g of o-nitrophenol anion compound and the core-shell microspheres are added to the organic solvent and stirred at 40°C for 20h to graft phenoloxy anion groups onto the core-shell microspheres. After the reaction is completed, the reaction product is purified by centrifugation, washing and drying operations to obtain the catalyst of this embodiment.

[0038] The carbon dioxide cycloaddition reaction method of this embodiment is as follows: in a 50ml glass reactor, add 20ml of propylene oxide containing 0.5 wt% catalyst (PS-TMG-PhNO2), introduce carbon dioxide (99%) gas replacement three times, and then heat to 90°C under stirring. Stir the reaction at this temperature for 4h, continuously introduce carbon dioxide gas during the reaction, and maintain the reactor pressure at 1.5MPa. After the reaction is completed, stop the air intake and cool to room temperature, take samples for analysis, and the results show that the propylene oxide conversion rate (i.e., reaction conversion rate) is 98.5%, and the propylene carbonate selectivity (i.e., reaction selectivity) is 99.5%. For the infrared spectrum and electronic spectrum of the catalyst (PS-TMG-PhNO2) used in this embodiment, see Figure 1-2 shown.

[0039] Example 2 The difference between this embodiment and embodiment 1 is that the nitrogen-containing cationic group of the catalyst used is different. In this embodiment, the nitrogen-containing cationic group of the catalyst is a sodium hydroxide choline cationic group.

[0040] The carbon dioxide cycloaddition reaction method in Example 1 was used, and the catalyst was changed to a catalyst in which the nitrogen-containing cationic group in this example was a sodium hydroxide choline cationic group. After the reaction was completed, samples were taken for analysis, and the results showed that the propylene oxide conversion rate was 85.2% and the propylene carbonate selectivity was 98.6%.

[0041] Example 3 The difference between this embodiment and embodiment 1 is that the nitrogen-containing cationic group of the catalyst used is different. In this embodiment, the nitrogen-containing cationic group of the catalyst is a quaternary ammonium cationic group, and the quaternary ammonium cationic group is specifically a tetraethylammonium cationic group.

[0042] The carbon dioxide cycloaddition reaction method in Example 1 was used, and the catalyst was changed to a catalyst in which the nitrogen-containing cationic group in this example was a tetraethylammonium cationic group. After the reaction was completed, a sample was taken for analysis, and the results showed that the propylene oxide conversion rate was 82.4% and the propylene carbonate selectivity was 97.8%.

[0043] Example 4 The difference between this embodiment and embodiment 1 is that the R3 of the phenoloxy anion group of the catalyst used is different. In this embodiment, R3 is hydrogen (H).

[0044] The carbon dioxide cycloaddition reaction method in Example 1 was used, and the catalyst was changed to the catalyst in this example. After the reaction was completed, samples were taken for analysis, and the results showed that the propylene oxide conversion rate was 90.6%, and the propylene carbonate selectivity was 99.2%.

[0045] Example 5 The difference between this embodiment and embodiment 1 is that the R3 of the phenoloxy anion group of the catalyst used is different. In this embodiment, R3 is a hydroxyl group (OH).

[0046] The carbon dioxide cycloaddition reaction method in Example 1 was used, and the catalyst was changed to the catalyst in this example. After the reaction was completed, samples were taken for analysis, and the results showed that the propylene oxide conversion rate was 86.7% and the propylene carbonate selectivity was 98.7%.

[0047] Example 6 The difference between this embodiment and embodiment 1 is that the R3 of the phenoloxy anion group of the catalyst used is different. In this embodiment, R3 is a methoxy group (OCH3).

[0048] The carbon dioxide cycloaddition reaction method in Example 1 was used, and the catalyst was changed to the catalyst in this example. After the reaction was completed, samples were taken for analysis, and the results showed that the propylene oxide conversion rate was 82.5%, and the propylene carbonate selectivity was 97.5%.

[0049] Example 7 The difference between this embodiment and embodiment 1 is that the R3 containing the phenoloxy anion group of the catalyst used is different. In this embodiment, R3 is an amine group (NH2).

[0050] The carbon dioxide cycloaddition reaction method in Example 1 was used, and the catalyst was changed to the catalyst in this example. After the reaction was completed, samples were taken for analysis, and the results showed that the propylene oxide conversion rate was 93.4% and the propylene carbonate selectivity was 98.2%.

[0051] Example 8 The difference between this embodiment and embodiment 1 is that the R3 containing the phenoloxy anion group of the catalyst used is different. In this embodiment, R3 is chlorine.

[0052] The carbon dioxide cycloaddition reaction method in Example 1 was used, and the catalyst was changed to the catalyst in this example. After the reaction was completed, samples were taken for analysis, and the results showed that the propylene oxide conversion rate was 91.3% and the propylene carbonate selectivity was 99.1%.

[0053] Example 9 The carbon dioxide cycloaddition reaction method of this embodiment is as follows: 20 ml of propylene oxide containing 0.5 wt% catalyst (PS-TMG-PhNO2) is added to a 50 ml glass reactor, and carbon dioxide (99%) gas is introduced for replacement three times, and the temperature is raised to 70 ° C under stirring. The reaction is stirred at this temperature for 4 hours, and carbon dioxide gas is continuously introduced during the reaction, and the reactor pressure is maintained at 1.5 MPa. After the reaction is completed, the air intake is stopped and cooled to room temperature, and samples are taken for analysis. The results show that the conversion rate of propylene oxide is 75.1% and the selectivity of propylene carbonate is 99.9%.

[0054] Example 10 The carbon dioxide cycloaddition reaction method of this embodiment is as follows: 20 ml of propylene oxide containing 0.5 wt% catalyst (PS-TMG-PhNO2) is added to a 50 ml glass reactor, and carbon dioxide (99%) gas is introduced for replacement three times, and then the temperature is raised to 80 ° C under stirring. The reaction is stirred at this temperature for 4 hours, and carbon dioxide gas is continuously introduced during the reaction, and the reactor pressure is maintained at 1.5 MPa. After the reaction is completed, the air intake is stopped and cooled to room temperature, and samples are taken for analysis. The results show that the conversion rate of propylene oxide is 85.6%, and the selectivity of propylene carbonate is 99.9%.

[0055] Embodiment 11 The carbon dioxide cycloaddition reaction method of this embodiment is as follows: 20 ml of propylene oxide containing 0.5 wt% catalyst (PS-TMG-PhNO2) is added to a 50 ml glass reactor, and carbon dioxide (99%) gas is introduced for replacement three times, and then the temperature is raised to 100 ° C under stirring. The reaction is stirred at this temperature for 4 hours, and carbon dioxide gas is continuously introduced during the reaction, and the reactor pressure is maintained at 1.5 MPa. After the reaction is completed, the air intake is stopped and cooled to room temperature, and samples are taken for analysis. The results show that the conversion rate of propylene oxide is 99.9%, and the selectivity of propylene carbonate is 96.5%.

[0056] Example 12 The carbon dioxide cycloaddition reaction method of this embodiment is as follows: 20 ml of propylene oxide containing 0.5 wt% catalyst (PS-TMG-PhNO2) is added to a 50 ml glass reactor, and carbon dioxide (99%) gas is introduced for replacement three times, and then the temperature is raised to 110 ° C under stirring. The reaction is stirred at this temperature for 4 hours, and carbon dioxide gas is continuously introduced during the reaction, and the reactor pressure is maintained at 1.5 MPa. After the reaction is completed, the air intake is stopped and cooled to room temperature, and samples are taken for analysis. The results show that the conversion rate of propylene oxide is 99.9% and the selectivity of propylene carbonate is 94.6%.

[0057] Example 13 The difference between this embodiment and embodiment 1 is that the purity of the carbon dioxide gas is different. In this embodiment, the purity of the carbon dioxide gas is 20%.

[0058] The propylene oxide conversion rate of the carbon dioxide cycloaddition reaction method of this embodiment is 89.0%, and the propylene carbonate selectivity is 99.6%.

[0059] Embodiment 14 The difference between this embodiment and embodiment 1 is that the purity of the carbon dioxide gas is different. In this embodiment, the purity of the carbon dioxide gas is 30%.

[0060] The propylene oxide conversion rate of the carbon dioxide cycloaddition reaction method of this embodiment is 92.5%, and the propylene carbonate selectivity is 99.4%.

[0061] Embodiment 15 The difference between this embodiment and embodiment 1 is that the purity of the carbon dioxide gas is different. In this embodiment, the purity of the carbon dioxide gas is 50%.

[0062] The propylene oxide conversion rate of the carbon dioxide cycloaddition reaction method of this embodiment is 97.0%, and the propylene carbonate selectivity is 99.5%.

[0063] Example 16 The difference between this embodiment and embodiment 1 is that the purity of the carbon dioxide gas is different. In this embodiment, the purity of the carbon dioxide gas is 70%.

[0064] The propylene oxide conversion rate of the carbon dioxide cycloaddition reaction method of this embodiment is 98.4%, and the propylene carbonate selectivity is 99.8%.

[0065] Embodiment 17 The difference between this embodiment and embodiment 1 is that the purity of the carbon dioxide gas is different. In this embodiment, the purity of the carbon dioxide gas is 90%.

[0066] The propylene oxide conversion rate of the carbon dioxide cycloaddition reaction method of this embodiment is 98.7%, and the propylene carbonate selectivity is 99.5%.

[0067] Embodiment 18 The difference between this embodiment and embodiment 1 is that the reaction pressure (ie, the pressure in the reactor) is different. In the scheme of this embodiment, the reaction pressure is 0.1 MPa.

[0068] The propylene oxide conversion rate of the carbon dioxide cycloaddition reaction method of this embodiment is 73.5%, and the propylene carbonate selectivity is 96.3%.

[0069] Embodiment 19 The difference between this embodiment and embodiment 1 is that the reaction pressure (ie, the pressure in the reactor) is different. In the scheme of this embodiment, the reaction pressure is 0.5 MPa.

[0070] The propylene oxide conversion rate of the carbon dioxide cycloaddition reaction method of this embodiment is 79.6%, and the propylene carbonate selectivity is 97.1%.

[0071] Embodiment 20 The difference between this embodiment and embodiment 1 is that the reaction pressure (ie, the pressure in the reactor) is different. In the scheme of this embodiment, the reaction pressure is 2 MPa.

[0072] The propylene oxide conversion rate of the carbon dioxide cycloaddition reaction method of this embodiment is 99.1%, and the propylene carbonate selectivity is 99.6%.

[0073] Embodiment 21 The difference between this embodiment and embodiment 1 is that the reaction pressure (ie, the pressure in the reactor) is different. In the scheme of this embodiment, the reaction pressure is 3 MPa.

[0074] The propylene oxide conversion rate of the carbon dioxide cycloaddition reaction method of this embodiment is 99.7, and the propylene carbonate selectivity is 99.8%.

[0075] From the above Examples 1-21, it can be seen that the carbon dioxide cycloaddition reaction carried out using the catalyst of the present invention has good reaction selectivity and reaction conversion rate.

[0076] According to Examples 1-3, it can be seen that compared with sodium hydroxide choline cationic groups and quaternary ammonium cationic groups, the use of guanidinium cationic groups can better improve the reaction selectivity and reaction conversion rate. This may be because the guanidinium cationic group contains more amine groups, which can improve the absorption capacity of CO2, thereby improving the reaction selectivity and reaction conversion rate.

[0077] According to Example 1 and Examples 4-8, it can be seen that when R3 containing a phenoloxy anion group is a nitro group, the reaction selectivity and reaction conversion rate of the carbon dioxide cycloaddition reaction are better. This may be because the use of a nitro group as R3 can appropriately reduce the electron cloud density of the phenoloxy anion and appropriately reduce the nucleophilicity of the phenoloxy anion, thereby making it easier to transfer the carbonate species generated after activating CO2, thereby improving the reaction selectivity and reaction conversion rate.

[0078] According to Example 1 and Examples 9-12, it can be seen that the carbon dioxide cycloaddition reaction method of the present invention can achieve better reaction selectivity and reaction conversion rate in the range of 70~110°C. Among them, the reaction selectivity and reaction conversion rate are best when the reaction temperature is 90°C. Among them, when the reaction temperature is 70°C, the reaction conversion rate can reach 75.1%, and the reaction selectivity can reach 99.9%. It can be seen from this that the carbon dioxide cycloaddition reaction method of the present invention can still achieve good reaction selectivity and reaction conversion rate when the reaction temperature is low.

[0079] It can be seen from Example 1 and Example 13-17 that the carbon dioxide cycloaddition reaction method of the present invention can achieve better reaction selectivity and reaction conversion rate when the purity of carbon dioxide is in the range of 20%-99%. Wherein, when the purity of carbon dioxide is 20%, the reaction conversion rate can reach 89.0%, and the reaction selectivity can reach 99.6%. It can be seen from this that the carbon dioxide cycloaddition reaction method of the present invention can still achieve good reaction selectivity and reaction conversion rate when the concentration of carbon dioxide is low.

[0080] According to Example 1 and Examples 18-21, it can be seen that the carbon dioxide cycloaddition reaction method of the present invention can achieve better reaction selectivity and reaction conversion rate within the range of 0.1 to 3Mpa. It can be seen from this that the carbon dioxide cycloaddition reaction method of the present invention can still achieve good reaction selectivity and reaction conversion rate when the reaction pressure is low.

[0081] In summary, the catalyst of the present invention has good catalytic performance. Applying the catalyst to the cycloaddition reaction can effectively reduce the cost of the cycloaddition reaction, and help reduce the requirements of the cycloaddition reaction on the reaction conditions (including CO2 gas purity, reaction pressure, etc.), thereby improving the reaction selectivity and reaction conversion rate of the cycloaddition reaction.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A catalyst for catalyzing carbon dioxide cycloaddition reaction, characterized in that: The structural formula of the catalyst is: ， Among them, poly core For the polystyrene core, poly shell For poly(p-chloromethylstyrene) shell, Cation N + is a nitrogen-containing cationic group; Anion O - is a phenoloxy-containing anion group; Wherein, the structural formula of the phenoloxy anion group is: ， Wherein, R3 is any one of hydrogen, hydroxyl, methoxy, amino, nitro, and chlorine.

2. The catalyst according to claim 1, characterized in that The nitrogen-containing cationic group is any one of the following groups: a sodium hydroxide choline cationic group, a quaternary ammonium cationic group, and a guanidine compound cationic group; preferably, the nitrogen-containing cationic group is a guanidine compound cationic group.

3. The catalyst according to claim 2, characterized in that The nitrogen-containing cationic group is a sodium hydroxide choline cationic group.

4. The catalyst according to claim 2, characterized in that The nitrogen-containing cationic group is a quaternary ammonium cationic group.

5. The catalyst according to claim 2, characterized in that The nitrogen-containing cationic group is a guanidine compound cationic group, and the guanidine compound cationic group is a guanidinium cationic group.

6. The catalyst according to claim 5, characterized in that The guanidinium cationic group is 2-methyl-1,1,3,3-tetramethylguanidine.

7. The catalyst according to any one of claims 1 to 6, characterized in that The R3 is a nitro group, and the phenoloxy-containing anion group is an o-nitrophenol anion group.

8. The catalyst according to claim 1, characterized in that The nitrogen-containing cationic group is 2-methyl-1,1,3,3-tetramethylguanidine, the phenoloxy-containing anionic group is an o-nitrophenol anionic group, and the structural formula of the catalyst is: 。 9. A method for preparing the catalyst according to any one of claims 1 to 8, characterized in that: include: The polystyrene microspheres are dispersed in an organic solvent containing p-chloromethylstyrene monomer; adding an initiator and an emulsifier to an organic solvent to obtain a mixed solution; heating the mixed solution to perform a seed emulsion polymerization reaction to form core-shell microspheres; reacting the core-shell microspheres with a nitrogen-containing cationic compound in anhydrous ethanol to graft nitrogen-containing cationic groups onto the core-shell microspheres; The phenoloxy-containing anion compound and the core-shell microspheres are added into an organic solvent, and the organic solvent is stirred to graft the phenoloxy-containing anion groups onto the core-shell microspheres.

10. A carbon dioxide cycloaddition reaction method, characterized in that: Using the catalyst according to any one of claims 1 to 8, with carbon dioxide gas and an epoxy compound as raw materials, a cycloaddition reaction is carried out to generate a cyclic carbonate; Preferably, the amount of the catalyst is 0.05-2wt% of the amount of the epoxy compound; Preferably, the amount of the catalyst is 0.2-1wt% of the amount of the epoxy compound; Preferably, the purity of the carbon dioxide gas is 20%-99%; Preferably, the purity of the carbon dioxide gas is 30%-99%.

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