Catalyst for producing chain carbonate and preparation method thereof

Abstract

The invention discloses a catalyst for producing chain carbonate and a preparation method thereof, and belongs to the technical field of catalysts. The method comprises the following steps: firstly preparing a pre-swelling epoxy group functionalized porous polymer carrier, then reacting a 1, 3-dimethylimidazole iodized salt ethanol solution with an imidazole ethanol solution, filtering, distilling and purifying twice to obtain filter residue C, and finally performing reflux reaction on the filter residue C and the carrier in N, N-dimethylformamide to obtain the catalyst. And carrying out reduced pressure distillation, filtering, washing and drying to obtain the catalyst for producing chain carbonate. The preparation process is controllable in parameters, the obtained catalyst is high in catalytic activity, capable of improving the yield and purity of chain carbonate, good in stability, high in recovery rate and reusable, the problems that an existing catalyst is difficult to separate, activity is prone to attenuation and the like are solved, and the preparation process is simple and convenient and suitable for large-scale production.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, and more specifically to a catalyst for the production of chain carbonates and a method for preparing the same. Background Technology

[0002] Chain carbonates, as a class of high-value-added organic compounds, have shown broad application prospects in various fields such as coatings, adhesives, and lithium battery electrolytes, and their market demand continues to grow. Currently, the main industrial methods for producing chain carbonates include transesterification, phosgene reaction, and carbon dioxide-epoxide addition reaction. Among these, transesterification has become the mainstream process due to its advantages such as mild reaction conditions and readily available raw materials. Catalysts, as the core of the transesterification reaction, directly affect reaction efficiency, product yield, and purity. Therefore, developing high-performance catalysts is crucial for promoting the development of the chain carbonate industry.

[0003] There are many types of catalysts currently used for transesterification, including alkali metal compounds, metal oxides, and ionic liquids. However, these catalysts generally have certain limitations: some homogeneous catalysts, although highly active, are difficult to separate from the reaction system and are difficult to recover, which not only increases production costs but may also affect product purity; heterogeneous catalysts often face problems such as insufficient exposure of active sites and low catalytic efficiency, and are prone to loss of active components during the reaction, resulting in poor catalyst stability. In addition, some catalysts have harsh requirements for reaction conditions, requiring high temperature and high pressure environments, which increases energy consumption and safety risks in industrial production.

[0004] With the deepening of the green chemical engineering concept, industrial production has placed higher demands on the environmental friendliness, economy, and sustainability of catalysts. Existing catalysts can no longer meet the needs of actual production in terms of reusability, product selectivity, and environmental friendliness, necessitating the development of novel catalysts with high catalytic activity, good selectivity, strong stability, and easy recovery. Meanwhile, the preparation processes of existing catalysts are often complex or rely on expensive raw materials, limiting their large-scale application. Therefore, simplifying the preparation process and reducing production costs have become pressing issues in the current catalyst research and development field. Summary of the Invention

[0005] To address the problems mentioned in the background section, the present invention provides a method for preparing a catalyst for the production of chain carbonates.

[0006] In a first aspect, the present invention provides a method for preparing a catalyst for producing chain carbonates, comprising the following steps:

[0007] Step S1: Add 1,3-dimethylimidazolium iodide to anhydrous ethanol, stir to dissolve, and obtain 1,3-dimethylimidazolium iodide ethanol solution;

[0008] Step S2: Add imidazole and potassium hydroxide to anhydrous ethanol, stir to dissolve, and obtain imidazole ethanol solution;

[0009] Step S3: Add the imidazole ethanol solution dropwise to the 1,3-dimethylimidazolium iodide ethanol solution. After the addition is complete, the imidazole salt reaction solution is obtained. Filter the imidazole salt reaction solution to obtain precipitate A and filtrate.

[0010] Step S4: Distill the filtrate for the first time until no distillate flows out. Add the first portion of methanol and distill for the second time until no distillate flows out to obtain the distillate. Add the distillate to the second portion of methanol and stir well to obtain the distillate mixture. Filter the distillate mixture to obtain precipitate B.

[0011] Step S5: Mix precipitate A and precipitate B to obtain filter residue C. Add filter residue C to N,N-dimethylformamide and pre-swollen epoxy-functionalized porous polymer support. Heat and reflux to react. After cooling, distill under reduced pressure, filter, wash and dry to obtain a catalyst for the production of chain carbonates.

[0012] Furthermore, the preparation method of the pre-swollen epoxy-functionalized porous polymer support is as follows:

[0013] Step A1: Glycidyl methacrylate, divinylbenzene, toluene and azobisisobutyronitrile are stirred and mixed to obtain the oil phase;

[0014] Step A2: Add polyvinyl alcohol to deionized water, heat and stir to obtain an aqueous phase;

[0015] Step A3: Add the oil phase to the aqueous phase and stir to disperse, forming an emulsion. The reaction is carried out under nitrogen protection. After the reaction is combined, filter and wash to obtain an epoxy-functionalized porous polymer carrier.

[0016] Step A4: Add the epoxy-functionalized porous polymer support to methanol, heat and stir, cool and then distill under reduced pressure to obtain the pre-swollen epoxy-functionalized porous polymer support.

[0017] Further, in step A1, the mass ratio of glycidyl methacrylate, divinylbenzene, toluene and azobisisobutyronitrile is 10:(3-8):(20-40):(0.2-0.8).

[0018] Furthermore, in step A1, the stirring and mixing time is 15 min-30 min, and the mixing speed is 150 rpm-250 rpm.

[0019] Furthermore, in step A2, the mass ratio of polyvinyl alcohol to deionized water is 1:(50-100).

[0020] Furthermore, in step A2, the heating temperature is 70℃-95℃, the stirring time is 30min-60min, and the stirring speed is 200rpm-300rpm.

[0021] Further, in step A3, the mass ratio of oil phase to water phase is 1:(3-8), the reaction temperature under nitrogen protection is 60℃-85℃, and the reaction time is 6h-12h; the stirring speed is maintained at 200rpm-300rpm during the reaction; after the reaction is completed, the mixture is cooled to room temperature before filtration.

[0022] Further, in step A4, the mass ratio of the epoxy-functionalized porous polymer support to methanol is 1:(5-10); the heating temperature is 40℃-60℃, the stirring time is 2h-6h, the vacuum distillation temperature is 50℃-70℃, and the distillation pressure is 0.06MPa-0.09MPa.

[0023] Further, in step S1, the mass ratio of 1,3-dimethylimidazolium iodide to anhydrous ethanol is 1:(5-12).

[0024] Further, in step S2, the mass ratio of imidazole, potassium hydroxide and anhydrous ethanol is 1:(0.8-1.2):(8-20).

[0025] Further, in step S3, the mass ratio of imidazole ethanol solution to 1,3-dimethylimidazolium iodide ethanol solution is 1:(1.5-3.0).

[0026] Further, in step S3, the dripping rate of the imidazole ethanol solution is 0.5%-2.0% of the total mass of the imidazole ethanol solution per minute. During the dripping process, the system temperature is controlled at 20℃-30℃. After the dripping is completed, the system is kept warm and stirred for 10-30 minutes before filtration. The filtration is carried out by vacuum filtration, with a filtration pressure of 0.03MPa-0.06MPa and a 0.22μm-0.45μm microporous membrane as the filter medium.

[0027] Further, in step S4, the mass ratio of the first portion of methanol to the filtrate is 1:(3-6), and the mass ratio of the second portion of methanol to the distillate is 1:(2-5); the temperature of the first distillation is 60℃-70℃, and the distillation pressure is 0.06MPa-0.09MPa; the temperature of the second distillation is 70℃-80℃, and the distillation pressure is 0.06MPa-0.09MPa.

[0028] Further, in step S5, the mass ratio of filter residue C, N,N-dimethylformamide and pre-swollen epoxy-functionalized porous polymer carrier is 1:(10-25):(3-8); the reflux reaction temperature is 80℃-110℃, the reflux reaction time is 4h-10h; the vacuum distillation temperature is 70℃-90℃, the distillation pressure is 0.05MPa-0.08MPa, and the distillation is carried out until the system volume is 1 / 5-1 / 3 of the initial volume.

[0029] Furthermore, in step S5, the filtration is carried out by vacuum filtration with a filtration pressure of 0.03MPa-0.06MPa, the washing is carried out by washing with N,N-dimethylformamide 2-3 times, and the drying is carried out by vacuum drying with a drying temperature of 80℃-90℃, a drying time of 6h-12h, and a vacuum degree of 0.04MPa-0.07MPa.

[0030] In a second aspect, the present invention provides a method for preparing a catalyst for producing chain carbonates, and the catalyst obtained from the method is used to produce chain carbonates.

[0031] The beneficial effects of this invention are:

[0032] 1. The catalyst prepared by this invention for the production of chain carbonates has excellent catalytic performance and can efficiently catalyze related reactions to generate chain carbonates. Its unique preparation process allows the active ingredients to be well combined with the support, ensuring that the active sites are fully exposed during the catalytic process, thereby effectively promoting the smooth progress of the reaction and greatly improving the generation efficiency of the target product, providing efficient catalytic support for the large-scale production of chain carbonates.

[0033] 2. The catalyst prepared by this invention for the production of chain carbonates has good selectivity for the target reaction, can reduce the occurrence of side reactions, reduce the amount of impurities generated, and make the final chain carbonate product of higher quality, which can better meet the strict requirements of subsequent application scenarios for product purity.

[0034] 3. The catalyst prepared by this invention for the production of chain carbonates exhibits excellent stability and reusability, maintaining good catalytic activity and structural integrity even after multiple reaction cycles. With simple recycling treatment, it can be reused in the reaction system, reducing catalyst consumption costs and waste generation during production, aligning with green and environmentally friendly production principles, and improving the overall economic efficiency and sustainability of the production process. Detailed Implementation

[0035] To make the implementation methods of this application easier to understand, the application will be described in detail below with reference to specific embodiments. These embodiments are for illustrative purposes only and are not limited to the application scope of this application.

[0036] The specific parameters of the raw materials used in this invention are as follows:

[0037] In the examples below, the microporous filter membrane is a nylon microporous filter membrane, purchased from Hangzhou Micro-Pai Technology Co., Ltd.

[0038] Example 1

[0039] A method for preparing a catalyst for producing chain carbonates includes the following preparation steps:

[0040] The preparation method of the pre-swollen epoxy-functionalized porous polymer support is as follows:

[0041] Step A1: Glycidyl methacrylate, divinylbenzene, toluene, and azobisisobutyronitrile were stirred at 150 rpm for 15 min at room temperature to obtain the oil phase; the mass ratio of glycidyl methacrylate, divinylbenzene, toluene, and azobisisobutyronitrile was 10:3:20:0.2.

[0042] Step A2: Add polyvinyl alcohol to deionized water, stir at 200 rpm for 30 min at 70°C, and cool to room temperature to obtain the aqueous phase; the mass ratio of polyvinyl alcohol to deionized water is 1:50.

[0043] Step A3: Add the oil phase to the aqueous phase and stir to disperse, forming an emulsion. React at 60°C for 6 hours under nitrogen protection. After the reaction is complete, cool to room temperature, filter, and wash twice with deionized water to obtain an epoxy-functionalized porous polymer carrier; the mass ratio of oil phase to aqueous phase is 1:3.

[0044] Step A4: Add the epoxy-functionalized porous polymer support to methanol, stir at 40°C for 2 hours, cool and then distill under reduced pressure at 50°C and 0.06 MPa for 1 hour to obtain the pre-swollen epoxy-functionalized porous polymer support; the mass ratio of the epoxy-functionalized porous polymer support to methanol is 1:5.

[0045] The preparation method of the catalyst used for the production of chain carbonates is as follows:

[0046] Step S1: Add 1,3-dimethylimidazolium iodide to anhydrous ethanol and stir to dissolve, to obtain a 1,3-dimethylimidazolium iodide ethanol solution; the mass ratio of 1,3-dimethylimidazolium iodide to anhydrous ethanol is 1:5;

[0047] Step S2: Add imidazole and potassium hydroxide to anhydrous ethanol, stir to dissolve, and obtain an imidazole ethanol solution; the mass ratio of imidazole, potassium hydroxide and anhydrous ethanol is 1:0.8:8;

[0048] Step S3: Add the imidazole ethanol solution dropwise to the 1,3-dimethylimidazolium iodide ethanol solution, controlling the dropwise addition rate to 0.5% / min of the total mass of the imidazole ethanol solution. Maintain the system temperature at 20℃ during the dropwise addition. After the addition is complete, keep the temperature and stir for 10 min to obtain the imidazole salt reaction solution. Filter the imidazole salt reaction solution using vacuum filtration at a pressure of 0.03 MPa. Use a 0.22 μm nylon microporous membrane as the filter medium to obtain precipitate A and filtrate. The mass ratio of the imidazole ethanol solution to the 1,3-dimethylimidazolium iodide ethanol solution is 1:1.5.

[0049] Step S4: The filtrate is first distilled (distillation temperature 60℃, distillation pressure 0.06MPa) until no distillate flows out. After adding the first portion of methanol, a second distillation is performed (distillation temperature 70℃, distillation pressure 0.06MPa) until no distillate flows out, yielding a distillate. The distillate is added to the second portion of methanol and stirred evenly to obtain a distillate mixture. The distillate mixture is filtered to obtain precipitate B. The mass ratio of the first portion of methanol to the filtrate is 1:3, and the mass ratio of the second portion of methanol to the distillate is 1:2.

[0050] Step S5: Mix precipitate A and precipitate B to obtain filter residue C. Add filter residue C to N,N-dimethylformamide and pre-swollen epoxy-functionalized porous polymer support. Reflux at 80°C for 4 hours. After cooling, distill under reduced pressure (distillation temperature 70°C, distillation pressure 0.05 MPa, distillation to 1 / 3 of the initial volume). Then filter under reduced pressure (filtration pressure 0.03 MPa), wash twice with N,N-dimethylformamide, and vacuum dry at 80°C for 6 hours at a vacuum degree of 0.04 MPa to obtain a catalyst for the production of chain carbonates. The mass ratio of filter residue C, N,N-dimethylformamide, and pre-swollen epoxy-functionalized porous polymer support is 1:10:3.

[0051] Example 2

[0052] A method for preparing a catalyst for producing chain carbonates includes the following preparation steps:

[0053] Preparation of pre-swollen epoxy-functionalized porous polymer supports

[0054] Step A1: Glycidyl methacrylate, divinylbenzene, toluene, and azobisisobutyronitrile were stirred at 200 rpm for 22 min at room temperature to obtain the oil phase; the mass ratio of glycidyl methacrylate, divinylbenzene, toluene, and azobisisobutyronitrile was 10:5.5:30:0.5.

[0055] Step A2: Add polyvinyl alcohol to deionized water, stir at 250 rpm for 45 min at 82°C, and cool to room temperature to obtain the aqueous phase; the mass ratio of polyvinyl alcohol to deionized water is 1:75.

[0056] Step A3: Add the oil phase to the aqueous phase and stir to disperse, forming an emulsion. React at 72°C for 9 hours under nitrogen protection. After the reaction is complete, cool to room temperature, filter, and wash twice with deionized water to obtain an epoxy-functionalized porous polymer carrier. The mass ratio of oil phase to aqueous phase is 1:5.5.

[0057] Step A4: Add the epoxy-functionalized porous polymer support to methanol, stir at 50°C for 4 hours, cool and then distill under reduced pressure at 60°C and 0.075 MPa for 2 hours to obtain the pre-swollen epoxy-functionalized porous polymer support; the mass ratio of the epoxy-functionalized porous polymer support to methanol is 1:7.5.

[0058] The preparation method of the catalyst used for the production of chain carbonates is as follows:

[0059] Step S1: Add 1,3-dimethylimidazolium iodide to anhydrous ethanol and stir at 225 rpm for 60 min at 27 °C to obtain an ethanol solution of 1,3-dimethylimidazolium iodide; the mass ratio of 1,3-dimethylimidazolium iodide to anhydrous ethanol is 1:8.5.

[0060] Step S2: Add imidazole and potassium hydroxide to anhydrous ethanol and stir at 275 rpm for 80 min at 32 °C to obtain an imidazole ethanol solution; the mass ratio of imidazole, potassium hydroxide and anhydrous ethanol is 1:1.0:14.

[0061] Step S3: Add the imidazole ethanol solution dropwise to the 1,3-dimethylimidazolium iodide ethanol solution, controlling the dropwise addition rate to 1.3% / min of the total mass of the imidazole ethanol solution. Maintain the system temperature at 25℃ during the dropwise addition. After the addition is complete, keep the system at this temperature and stir for 20 min to obtain the imidazole salt reaction solution. Filter the imidazole salt reaction solution using vacuum filtration (filtration pressure 0.05 MPa, filter medium 0.35 μm nylon microporous membrane) to obtain precipitate A and filtrate. The mass ratio of imidazole ethanol solution to 1,3-dimethylimidazolium iodide ethanol solution is 1:2.25.

[0062] Step S4: The filtrate is first distilled (distillation temperature 65℃, distillation pressure 0.08MPa) until no distillate flows out. After adding the first portion of methanol, a second distillation is performed (distillation temperature 75℃, distillation pressure 0.08MPa) until no distillate flows out, yielding a distillate. The distillate is added to the second portion of methanol and stirred evenly to obtain a distillate mixture. The distillate mixture is filtered to obtain precipitate B. The mass ratio of the first portion of methanol to the filtrate is 1:4.5, and the mass ratio of the second portion of methanol to the distillate is 1:3.5.

[0063] Step S5: Mix precipitate A and precipitate B to obtain filter residue C. Add filter residue C to N,N-dimethylformamide and pre-swollen epoxy-functionalized porous polymer support. Reflux at 95°C for 7 hours. After cooling, perform vacuum distillation (distillation temperature 80°C, distillation pressure 0.07 MPa, distillation to 1 / 4 of the initial volume). Then filter under reduced pressure (filtration pressure 0.05 MPa), wash twice with N,N-dimethylformamide, and then vacuum dry (drying temperature 85°C, drying time 9 hours, vacuum degree 0.05 MPa) to obtain a catalyst for the production of chain carbonates. The mass ratio of filter residue C, N,N-dimethylformamide, and pre-swollen epoxy-functionalized porous polymer support is 1:17.5:5.5.

[0064] Example 3

[0065] A method for preparing a catalyst for producing chain carbonates includes the following preparation steps:

[0066] Preparation of pre-swollen epoxy-functionalized porous polymer supports

[0067] Step A1: Glycidyl methacrylate, divinylbenzene, toluene and azobisisobutyronitrile were stirred at 250 rpm for 30 min at room temperature to obtain the oil phase; the mass ratio of glycidyl methacrylate, divinylbenzene, toluene and azobisisobutyronitrile was 10:8:40:0.8.

[0068] Step A2: Add polyvinyl alcohol to deionized water, stir at 300 rpm for 60 min at 95°C, and cool to room temperature to obtain the aqueous phase; the mass ratio of polyvinyl alcohol to deionized water is 1:100.

[0069] Step A3: Add the oil phase to the aqueous phase and stir to disperse, forming an emulsion. React at 85°C for 12 hours under nitrogen protection. After the reaction is complete, cool to room temperature, filter, and wash three times with deionized water to obtain an epoxy-functionalized porous polymer carrier. The mass ratio of oil phase to aqueous phase is 1:8.

[0070] Step A4: Add the epoxy-functionalized porous polymer support to methanol, stir at 60°C for 6 hours, cool and then distill under reduced pressure at 70°C and 0.09 MPa for 3 hours to obtain the pre-swollen epoxy-functionalized porous polymer support; the mass ratio of the epoxy-functionalized porous polymer support to methanol is 1:10.

[0071] The preparation method of the catalyst used for the production of chain carbonates is as follows:

[0072] Step S1: Add 1,3-dimethylimidazolium iodide to anhydrous ethanol and stir at 300 rpm for 90 min at 35 °C to obtain an ethanol solution of 1,3-dimethylimidazolium iodide; the mass ratio of 1,3-dimethylimidazolium iodide to anhydrous ethanol is 1:12.

[0073] Step S2: Add imidazole and potassium hydroxide to anhydrous ethanol and stir at 350 rpm for 120 min at 40 °C to obtain an imidazole ethanol solution; the mass ratio of imidazole, potassium hydroxide and anhydrous ethanol is 1:1.2:20.

[0074] Step S3: Add the imidazole ethanol solution dropwise to the 1,3-dimethylimidazolium iodide ethanol solution, controlling the dropwise addition rate to be 2.0% / min of the total mass of the imidazole ethanol solution. Maintain the system temperature at 30℃ during the dropwise addition. After the dropwise addition is complete, keep the system at this temperature and stir for 30 min to obtain the imidazole salt reaction solution. Filter the imidazole salt reaction solution using vacuum filtration (filtration pressure 0.06 MPa, filter medium is 0.45 μm nylon microporous membrane) to obtain precipitate A and filtrate. The mass ratio of imidazole ethanol solution to 1,3-dimethylimidazolium iodide ethanol solution is 1:3.0.

[0075] Step S4: The filtrate is first distilled (distillation temperature 70℃, distillation pressure 0.09MPa) until no distillate flows out. After adding the first portion of methanol, a second distillation is performed (distillation temperature 80℃, distillation pressure 0.09MPa) until no distillate flows out, yielding a distillate. The distillate is added to the second portion of methanol and stirred evenly to obtain a distillate mixture. The distillate mixture is filtered to obtain precipitate B. The mass ratio of the first portion of methanol to the filtrate is 1:6, and the mass ratio of the second portion of methanol to the distillate is 1:5.

[0076] Step S5: Mix precipitate A and precipitate B to obtain filter residue C. Add filter residue C to N,N-dimethylformamide and pre-swollen epoxy-functionalized porous polymer support. Reflux at 110℃ for 10 h. After cooling, perform vacuum distillation (distillation temperature 90℃, distillation pressure 0.08 MPa, distillation to 1 / 5 of the initial volume). Then filter under reduced pressure (filtration pressure 0.06 MPa), wash three times with N,N-dimethylformamide, and then vacuum dry (drying temperature 90℃, drying time 12 h, vacuum degree 0.07 MPa) to obtain a catalyst for the production of chain carbonates. The mass ratio of filter residue C, N,N-dimethylformamide, and pre-swollen epoxy-functionalized porous polymer support is 1:25:8.

[0077] Comparative Example 1:

[0078] Compared with Example 1, this comparative example only modifies the preparation steps of the pre-swollen epoxy-functionalized porous polymer support, deletes step A4 (pre-swelling treatment), and directly uses the epoxy-functionalized porous polymer support obtained in step A3 to participate in the reaction in step S5. The remaining steps, raw material ratios and process parameters are completely consistent with Example 1, and a catalyst for the production of chain carbonates is obtained.

[0079] Comparative Example 2:

[0080] Compared with Example 1, this comparative example replaces "glycidyl methacrylate" with an equal mass of "methyl methacrylate". All other steps, raw material ratios and process parameters are completely consistent with Example 1, resulting in a catalyst for the production of chain carbonates.

[0081] Comparative Example 3:

[0082] Compared with Example 1, this comparative example omits all steps of "preparation of pre-swollen epoxy-functionalized porous polymer support" and does not add any support in step S5. Only filter residue C is added to N,N-dimethylformamide for reflux reaction. The subsequent vacuum distillation, filtration, washing and drying steps remain unchanged. The remaining raw material ratios and process parameters are consistent with those of Example 1, and a catalyst for the production of chain carbonates is obtained.

[0083] Application Example 1:

[0084] Methanol and propylene carbonate were added to a three-necked flask and stirred until homogeneous. Then, the catalyst prepared in Example 1 for the production of chain carbonates was added. The mixture was refluxed at 67°C for 6 hours. After the reaction was completed, the mixture was cooled to room temperature. The reaction solution was filtered under reduced pressure (0.04 MPa, 0.45 μm nylon microporous membrane) to obtain a filter residue and a filtrate. The filtrate was then distilled under reduced pressure (67°C, 0.07 MPa) for 3 hours to obtain dimethyl carbonate. The mass ratio of methanol to propylene carbonate was 2.5:1, and the amount of catalyst accounted for 4% of the total mass of methanol and propylene carbonate.

[0085] The filter residue after vacuum filtration was retained on the original filter membrane without transfer. DMF was sprayed onto the surface of the filter residue for washing. The amount of DMF used was 3:1 (the ratio of DMF to the catalyst used to produce chain carbonates was 3:1). After washing, the filter residue was vacuum dried for 5 hours at a vacuum degree of 0.05 MPa and a vacuum drying temperature of 60°C to obtain recovered catalyst 1.

[0086] Application Example 2:

[0087] Compared with Application Example 1, the catalyst prepared in Example 1 for the production of chain carbonates was replaced with the catalyst prepared in Example 2 for the production of chain carbonates, and the remaining steps and parameters were the same as in Application Example 1, to obtain dimethyl carbonate and recycled catalyst 1.

[0088] Application Example 3:

[0089] Compared with Application Example 1, the catalyst prepared in Example 1 for the production of chain carbonates was replaced with the catalyst prepared in Example 3 for the production of chain carbonates, and the remaining steps and parameters were the same as in Application Example 1, to obtain dimethyl carbonate and recycled catalyst 1.

[0090] Application Example 4:

[0091] Compared with Application Example 1, the catalyst prepared in Example 1 for the production of chain carbonates was replaced with the catalyst prepared in Comparative Example 1 for the production of chain carbonates. All other steps and parameters were the same as in Application Example 1, resulting in dimethyl carbonate and recycled catalyst 1.

[0092] Application Example 5:

[0093] Compared with Application Example 1, the catalyst prepared in Example 1 for the production of chain carbonates was replaced with the catalyst prepared in Comparative Example 2 for the production of chain carbonates. All other steps and parameters were the same as in Application Example 1, resulting in dimethyl carbonate and recycled catalyst 1.

[0094] Application Example 6:

[0095] Compared with Comparative Example 3, the catalyst prepared in Example 1 for the production of chain carbonates was replaced with the catalyst prepared in Example 3 for the production of chain carbonates, and the remaining steps and parameters were the same as in Application Example 1, to obtain dimethyl carbonate and recycled catalyst 1.

[0096] Application Example 7:

[0097] Compared with Application Example 1, the catalyst prepared in Example 1 for the production of chain carbonates was replaced with the recycled catalyst 1 obtained in Application Example 1, and the remaining steps and parameters were the same as in Application Example 1, to obtain dimethyl carbonate and recycled catalyst 2.

[0098] Application Example 8:

[0099] Compared with Application Example 1, the catalyst prepared in Example 1 for the production of chain carbonates was replaced with the recycled catalyst 2 obtained in Application Example 7, and the remaining steps and parameters were the same as in Application Example 1, to obtain dimethyl carbonate and recycled catalyst 3.

[0100] Application Example 9:

[0101] Compared with Application Example 1, the catalyst prepared in Example 1 for the production of chain carbonates was replaced with the recycled catalyst 3 obtained in Application Example 8, and the remaining steps and parameters were the same as in Application Example 1, to obtain dimethyl carbonate and recycled catalyst 4.

[0102] Application Example 10:

[0103] Compared with Application Example 1, the catalyst prepared in Example 1 for the production of chain carbonates was replaced with the recycled catalyst 4 obtained in Application Example 9, and the remaining steps and parameters were the same as in Application Example 1, to obtain dimethyl carbonate and recycled catalyst 5.

[0104] The purity of dimethyl carbonate prepared according to examples 1-10 was tested, and the yield of dimethyl carbonate and the yield of recovered catalyst were calculated. The results are recorded in Table 1.

[0105] Dimethyl carbonate (DMC) purity determination: Dimethyl carbonate prepared in Examples 1-7 was used as a sample, and the purity of DMC was determined by gas chromatography-FID (GC-FID) external standard method. An HP-5 capillary column was selected as the separation column, and the column temperature program was set to an initial temperature of 80℃ for 3 min, followed by a temperature increase rate of 10℃ / min to 150℃. The injection port temperature was controlled at 200℃, and the detector (FID) temperature was set at 250℃ to ensure effective separation and detection response of sample components. A standard curve was plotted using DMC standards of known purity, and the DMC content in the sample was calculated.

[0106] Formula for calculating the yield of dimethyl carbonate:

[0107] Formula for calculating catalyst recovery rate:

[0108] Table 1: Purity, yield and catalyst recovery of dimethyl carbonate

[0109] Group DMC purity (GC, %) DMC yield (%) Catalyst recovery rate (%) Application Example 1 99.2 95.3 96.5 Application Example 2 99.5 96.8 97.2 Application Example 3 99.0 94.7 95.8 Application Example 4 98.3 93.5 94.2 Application Example 5 97.8 91.2 92.5 Application Example 6 96.5 88.6 89.8 Application Example 7 99.1 94.9 96.2 Application Example 8 98.8 94.1 95.0 Application Example 9 98.5 92.7 93.8 Application Example 10 98.0 90.5 93.1

[0110] Based on the data in Table 1, we can see that:

[0111] Application Example 1: The catalyst prepared in Example 1 uses a pre-swollen epoxy-functionalized porous polymer support, ensuring sufficient binding of the active component to the support and complete exposure of active sites. Therefore, the DMC purity reaches 99.2%, and the yield is 95.3%. Simultaneously, the porous structure of the support and the pre-swelling treatment enhance the catalyst's stability, resulting in a recovery rate of 96.5%. Overall, it exhibits excellent catalytic efficiency and recovery performance.

[0112] Application Example 2: The catalyst prepared in Example 2 was used. The process parameters (such as reaction temperature, time, and feed ratio) of Example 2 were within the optimized range, resulting in a more uniform loading of active ingredients and further improvement in catalytic selectivity and stability. Therefore, the DMC purity reached 99.5%, the highest among all groups, with a yield of 96.8% and a recovery rate of 97.2%, both superior to other groups, demonstrating the positive effect of process optimization on catalyst performance.

[0113] Application Example 3: The catalyst prepared in Example 3 was used. The process parameters (such as stirring speed and distillation temperature) in Example 3 were at a relatively high level. Although this ensured the full reaction of the active components, the excessively high reaction conditions led to slight aggregation of some active sites. Therefore, the DMC purity of 99.0%, yield of 94.7%, and recovery rate of 95.8% were slightly lower than those in Application Example 2, but still remained at a high level, which is consistent with the marginal effect law of process parameters.

[0114] Application Example 4: Comparative Example 1 omitted the pre-swelling treatment step of the support and directly used an epoxy-functionalized porous polymer support. The DMC purity of 98.3%, yield of 93.5%, and recovery rate of 94.2% were all lower than those of Example 1. The main reason is that the pore structure of the un-swelled support was not fully opened, resulting in uneven loading of the active ingredient and insufficient exposure of active sites. This reduced catalytic efficiency and selectivity, and also weakened the binding strength between the support and the active ingredient, leading to a small amount of loss during the recovery process.

[0115] Application Example 5: In Comparative Example 2, glycidyl methacrylate was replaced with methyl methacrylate, resulting in the loss of epoxy functional groups. The DMC purity (97.8%), yield (91.2%), and recovery rate (92.5%) decreased significantly because methyl methacrylate cannot provide epoxy sites. The active ingredient cannot form stable chemical bonds with the support and can only be physically adsorbed on the support surface. This leads to easy aggregation of active sites during the reaction, reduced selectivity and catalytic activity, and easy detachment of the active ingredient during recovery, resulting in a decreased recovery rate.

[0116] Application Example 6: Comparative Example 3 did not use any support, using only filter residue C as the catalyst. The DMC purity of 96.5%, yield of 88.6%, and recovery rate of 89.8% were the lowest among all groups. Due to the lack of support and dispersion, the active components in filter residue C were prone to agglomeration, resulting in insufficient exposure of active sites and a significant decrease in catalytic efficiency and selectivity. At the same time, without the dispersion and protection of a support, the active components were easily lost during the reaction and recovery process, which not only reduced the recovery rate but also further affected the efficiency of subsequent reactions due to the loss of active components.

[0117] Application Example 7: This catalyst was reused for the first time after being recovered in Application Example 1. The DMC purity of 99.1% decreased slightly by only 0.1% compared to the initial use, the yield of 94.9% decreased slightly by 0.4% compared to the initial value, and the recovery rate of 96.2% remained stable. This indicates that after the catalyst was recovered, its structural integrity was not damaged, the active components were not significantly lost, and the catalytic performance was basically maintained at the initial level, verifying its good reusability and meeting the requirements of sustainable utilization in green chemistry.

[0118] Application Example 8: When the catalyst was reused for the second time, although the DMC purity (98.8%), yield (94.1%), and recovery rate (95.0%) decreased slightly, they were still at a high level. The decrease may be due to a small amount of active ingredient being adsorbed onto the filter medium or slightly lost during washing during multiple recycling processes. However, the overall structure remained stable, and the catalytic performance declined slowly, further demonstrating the potential for long-term reuse of the catalyst and its ability to effectively reduce production costs.

[0119] Application Example 9: After the catalyst was reused for the third time, the DMC purity (98.5%), yield (92.7%), and recovery rate (93.8%) continued to decrease slightly, but were still significantly higher than the comparative examples without support or with improperly modified support. This indicates that although the active sites of the catalyst are slightly depleted after multiple cycles, the core catalytic structure is not destroyed, and it can still maintain highly efficient catalytic performance. Its stability far exceeds that of traditional catalysts, demonstrating the key role of functionalized support design in the preparation process.

[0120] Application Example 10: When the catalyst was reused for the fourth time, the DMC purity of 98.0%, the yield of 90.5%, and the recovery rate of 93.1% remained in a high range, decreasing by only 1.2%, 4.8%, and 3.4% respectively compared to the initial use. This result fully demonstrates that the catalyst has excellent long-term stability. Even after multiple recycling cycles, it can still meet the requirements of industrial production for catalytic efficiency, product purity, and recovery economy, solving the industry pain point of easy activity decay of existing catalysts.

[0121] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for preparing a catalyst for the production of chain carbonates, characterized in that, Includes the following steps: Step S1: Add 1,3-dimethylimidazolium iodide to anhydrous ethanol, stir to dissolve, and obtain 1,3-dimethylimidazolium iodide ethanol solution; Step S2: Add imidazole and potassium hydroxide to anhydrous ethanol, stir to dissolve, and obtain imidazole ethanol solution; Step S3: Add the imidazole ethanol solution dropwise to the 1,3-dimethylimidazolium iodide ethanol solution. After the addition is complete, the imidazole salt reaction solution is obtained. Filter the imidazole salt reaction solution to obtain precipitate A and filtrate. Step S4: Distill the filtrate for the first time until no distillate flows out. Add the first portion of methanol and distill for the second time until no distillate flows out to obtain the distillate. Add the distillate to the second portion of methanol and stir well to obtain the distillate mixture. Filter the distillate mixture to obtain precipitate B. Step S5: Mix precipitate A and precipitate B to obtain filter residue C. Add filter residue C to N,N-dimethylformamide and pre-swollen epoxy-functionalized porous polymer support. Heat and reflux to react. After cooling, distill under reduced pressure, filter, wash and dry to obtain a catalyst for the production of chain carbonates.

2. The method for preparing a catalyst for producing chain carbonates according to claim 1, characterized in that, The preparation method of the pre-swollen epoxy-functionalized porous polymer carrier is as follows: Step A1: Glycidyl methacrylate, divinylbenzene, toluene and azobisisobutyronitrile are stirred and mixed to obtain the oil phase; Step A2: Add polyvinyl alcohol to deionized water, heat and stir to obtain an aqueous phase; Step A3: Add the oil phase to the aqueous phase and stir to disperse, forming an emulsion. The reaction is carried out under nitrogen protection. After the reaction, filter and wash to obtain an epoxy-functionalized porous polymer carrier. Step A4: Add the epoxy-functionalized porous polymer support to methanol, heat and stir, cool and then distill under reduced pressure to obtain the pre-swollen epoxy-functionalized porous polymer support.

3. The method for preparing a catalyst for producing chain carbonates according to claim 2, characterized in that, In step A1, the mass ratio of glycidyl methacrylate, divinylbenzene, toluene, and azobisisobutyronitrile is 10:(3-8):(20-40):(0.2-0.8); In step A2, the mass ratio of polyvinyl alcohol to deionized water is 1:(50-100).

4. The method for preparing a catalyst for producing chain carbonates according to claim 2, characterized in that, In step A3, the mass ratio of oil phase to water phase is 1:(3-8), the reaction temperature under nitrogen protection is 60℃-85℃, and the reaction time is 6h-12h. In step A4, the mass ratio of the epoxy-functionalized porous polymer support to methanol is 1:(5-10); the heating and stirring temperature is 40℃-60℃, the stirring time is 2h-6h, the vacuum distillation temperature is 50℃-70℃, and the distillation pressure is 0.06MPa-0.09MPa.

5. A method for preparing a catalyst for producing chain carbonates according to claim 1, characterized in that, In step S1, the mass ratio of 1,3-dimethylimidazolium iodide to anhydrous ethanol is 1:(5-12).

6. The method for preparing a catalyst for producing chain carbonates according to claim 1, characterized in that, In step S2, the mass ratio of imidazole, potassium hydroxide and anhydrous ethanol is 1:(0.8-1.2):(8-20).

7. A method for preparing a catalyst for producing chain carbonates according to claim 1, characterized in that, In step S3, the mass ratio of imidazole ethanol solution to 1,3-dimethylimidazolium iodide ethanol solution is 1:(1.5-3.0).

8. A method for preparing a catalyst for producing chain carbonates according to claim 1, characterized in that, In step S4, the mass ratio of the first portion of methanol to the filtrate is 1:(3-6), and the mass ratio of the second portion of methanol to the distillate is 1:(2-5). The temperature of the first distillation is 60℃-70℃, and the distillation pressure is 0.06MPa-0.09MPa. The temperature of the second distillation is 70℃-80℃, and the distillation pressure is 0.06MPa-0.09MPa.

9. A method for preparing a catalyst for producing chain carbonates according to claim 1, characterized in that, In step S5, the mass ratio of filter residue C, N,N-dimethylformamide and pre-swollen epoxy-functionalized porous polymer carrier is 1:(10-25):(3-8); the reflux reaction temperature is 80℃-110℃, the reflux reaction time is 4h-10h; the vacuum distillation temperature is 70℃-90℃, and the distillation pressure is 0.05MPa-0.08MPa.

10. A catalyst for producing chain carbonates prepared by the method of any one of claims 1-9.