Catalyst for synthesizing 1, 3-dioxane-2-ketone as well as preparation method and application of catalyst

Abstract

The invention discloses a catalyst for synthesizing 1, 3-dioxane-2-ketone as well as a preparation method and application of the catalyst. The catalyst is prepared from the following components in percentage by mass: 60wt%-90wt% of a component A, 5wt%-20wt% of a component B and 5wt%-30wt% of a component C, wherein the component A is one or more of N, N-dimethyl formamide, N, N-dimethylacetamide, N, N-diethyl formamide and urea, and the component B is one or more of N, N-dimethyl formamide, N, N-dimethylacetamide, N, N-diethyl formamide and urea; the component B is one or more of lithium carbonate, sodium carbonate, potassium carbonate, cesium carbonate, calcium carbonate and magnesium carbonate; and the component C is 1-butyl-3-methylimidazolium tetrafluoroborate and / or 1-butyl-3-methylimidazolium hexafluorophosphate, and the component C is 1-butyl-3-methylimidazolium hexafluorophosphate. According to the present invention, the components of the catalyst have the mutual synergistic promotion effect, the reaction substrate can be adsorbed and activated, the reaction condition is mild, the product yield is high, the catalyst can be recovered and regenerated, and the environmental pollution is low.

Description

Technical Field

[0001] This invention belongs to the technical field of CO2 conversion and utilization, specifically relating to a catalyst for the preparation of 1,3-dioxane-2-one by carbon dioxide carbonylation, its preparation method, and its application. Background Technology

[0002] In recent years, the comprehensive utilization of carbon dioxide (CO2) has attracted increasing attention. Utilizing CO2 to prepare various inorganic and organic chemical products is one of the most promising approaches to achieving CO2 emission reduction and resource utilization. Currently, the resource utilization of CO2 as a raw material has achieved some considerable results, including the synthesis of energy products such as methanol and formic acid; fine chemicals such as acetyl carbonate, carbamates, carboxylic acids, and isocyanates; and polymer molecules such as polycarbonate and polyurethane. Among these, the synthesis of urea, methanol, formic acid, salicylic acid, cyclic carbonates, polycarbonate, and carboxylic acids using CO2 has already been industrialized. Although the resource utilization of CO2 has significant value and potential, the reactions currently used industrially are still very limited, and problems such as small production scale and simple product structure exist. Many valuable reactions remain in the laboratory research stage. Therefore, synthesizing more types of high-value-added fine chemicals using CO2 as a raw material under milder, greener, and simpler reaction conditions still faces significant challenges.

[0003] Biodegradable medical polymers possess excellent biocompatibility and mechanical properties, eliminating the need for secondary surgery to remove implants after use. Therefore, they are widely used in degradable ligation devices, controlled drug release, and in vivo implant materials (intraplasty, tissue engineering scaffolds). Biodegradable aliphatic polycarbonates not only exhibit good biocompatibility and mechanical properties but also allow for the modification of polyester polymer structures, flexibly altering their mechanical and degradation properties, thus occupying an important position in the field of biodegradable materials.

[0004] Polycondensation can only yield oligomers, while ring-opening polymerization offers controllable molecular weight, making it the preferred method for preparing biodegradable medical polymer materials. Therefore, the production of polyester monomers is the core of the manufacturing process. Currently, the domestic market for polycarbonate monomer raw materials is lacking, and imported monomer raw materials are expensive; thus, developing polycarbonate monomer raw material synthesis processes is particularly important.

[0005] 1,3-Dioxane-2-one can be synthesized via phosgene synthesis, transesterification, condensation of 1,3-propanediol with ethyl chloroformate, and CO2 cyclization. The phosgene synthesis is a common method for 1,3-dioxane-2-one, but phosgene is highly toxic and the reaction produces HCl gas, causing severe environmental pollution; therefore, it is gradually being phased out. The transesterification method synthesizes 1,3-dioxane-2-one through the transesterification reaction of 1,3-propanediol and diethyl carbonate. However, this method is limited by thermodynamic equilibrium, resulting in low selectivity, low product yield, difficult product purification, and low product purity. The ethyl chloroformate method and the triphosgene method require low temperatures, acid-binding agents, and large amounts of anhydrous solvents, making the subsequent product separation and purification processes extremely complex.

[0006] The cyclization of CO2 with 3-chloro-1-propanol to synthesize 1,3-dioxane-2-one is an ideal process route. However, most of the catalysts reported so far have low activity, and the reaction is severely affected by phase equilibrium, which prevents improvements in selectivity and yield. Overcoming the limitations imposed by phase equilibrium is a key problem that needs to be solved for this reaction. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a catalyst for the synthesis of 1,3-dioxane-2-one, its preparation method, and its applications. The catalyst of this invention exhibits synergistic promoting effects among its components, adsorbs and activates the reaction substrate, operates under mild reaction conditions, achieves high product yields, and the catalyst is recyclable and regenerable, resulting in minimal environmental pollution.

[0008] The catalyst for synthesizing 1,3-dioxane-2-one of the present invention comprises, by mass percentage, 60wt% to 90wt%, preferably 75wt% to 90wt% of component A, 5wt% to 20wt%, preferably 5wt% to 10wt% of component B, and 5wt% to 30wt%, preferably 10wt% to 20wt% of component C. Component A is one or more of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAC), N,N-diethylformamide (DEMF) and urea; Component B is one or more of Group IA and IIA carbonates; preferably one or more of lithium carbonate, sodium carbonate, potassium carbonate, cesium carbonate, calcium carbonate, and magnesium carbonate. Component C is 1-butyl-3-methylimidazolium tetrafluoroborate and / or 1-butyl-3-methylimidazolium hexafluorophosphate.

[0009] The preparation method of the catalyst for synthesizing 1,3-dioxane-2-one according to the present invention includes the following steps: mixing and dissolving components B, A, and C to obtain the catalyst. Specifically, component B is added to component A, and the mixture is stirred at 50-70°C for 1-4 hours. Heating is then stopped, and the solution is cooled to below 30°C. Component C is then added to the solution, and the mixture is stirred at 10-30°C for 0.5-2 hours.

[0010] The application of the catalyst of the present invention in the synthesis of 1,3-dioxane-2-one involves a cyclization reaction using CO2 and 3-chloro-1-propanol as raw materials.

[0011] The application includes the following: The above-mentioned catalyst for the synthesis of 1,3-dioxane-2-one is added to a reaction vessel, along with acetonitrile and 3-chloro-1-propanol. Pure CO2 is introduced as the reaction gas, the reaction pressure is 0.1-5 MPa, and the reaction temperature is 40-120℃. The mass ratio of the catalyst, 3-chloro-1-propanol, and solvent is 1~10:10:10~100.

[0012] The present invention has the following advantages: (1) All components A of the catalyst of this invention contain acyl structures, which can react rapidly with the reaction substrate to form active intermediates. Component C has high polarity and can effectively activate CO2 molecules to form an active state and react with the above-mentioned active intermediates. Component B provides an alkaline environment for the system, which not only facilitates the formation of active intermediates by components A and C, but also neutralizes the acidic byproducts formed during the reaction, which helps to regenerate components A and C and continue to participate in the catalytic cycle. It can adsorb and activate CO2. Compared with existing preparation methods, the reaction conditions are milder and the product yield is very high. (2) Compared with existing preparation methods, the present invention uses CO2 as a carbonylation reagent, which is abundant, inexpensive and readily available, with low cost and clean and pollution-free raw materials, and has high application value; the catalyst of the present invention can be recycled and regenerated, with little environmental pollution, which is beneficial to environmental protection. Attached Figure Description

[0013] Figure 1 The product obtained from the catalyst reaction in Example 1 1 H NMR spectrum. Detailed Implementation

[0014] The following non-limiting embodiments are intended to enable those skilled in the art to more fully understand the invention, but do not limit the invention in any way. Example 1

[0015] 10.0 g of cesium carbonate was added to 36.5 g of N,N-dimethylformamide and stirred at 70 °C for 2 hours. Heating was stopped and the temperature was lowered to 15 °C. 4.5 g of 1-butyl-3-methylimidazolium tetrafluoroborate was added and stirred at 15 °C for 1 hour to obtain catalyst C1. Example 2

[0016] Add 6.5g of sodium carbonate to 45.5g of N,N-dimethylacetamide and stir at 60°C for 2 hours. Stop heating and cool down to 30°C. Add 4.2g of 1-butyl-3-methylimidazolium tetrafluoroborate and stir at 30°C for 1 hour to obtain catalyst C2. Example 3

[0017] Add 4.5g of magnesium carbonate to 30g of urea and stir at 70℃ for 2 hours. Stop heating and cool down to 25℃. Add 14.2g of 1-butyl-3-methylimidazolium hexafluorophosphate and stir at 25℃ for 2 hours to obtain catalyst C3. Example 4

[0018] Add 3.6g of calcium carbonate to 60g of N,N-diethylformamide and stir at 50℃ for 4 hours. Stop heating and cool down to 20℃, then add 3.4g of 1-butyl-3-methylimidazolium hexafluorophosphate and stir at 20℃ for 0.5 hours to obtain catalyst C4.

[0019] The catalyst C5 was prepared in the same manner as in Example 1, except that cesium carbonate was not added.

[0020] Catalyst C6 was prepared in the same manner as in Example 2, except that 1-butyl-3-methylimidazolium tetrafluoroborate was not added. Example 5

[0021] The catalytic performance of catalysts C1-C6 in the examples and comparative examples was evaluated. Specifically, 10g of catalyst was placed in a 500mL stainless steel reactor, along with 31.2g of 3-chloro-1-propanol and 150g of acetonitrile. After checking the airtightness, pure CO2 gas was introduced, and the pressure inside the reactor was controlled at 0.4MPa. The reaction temperature was 40℃. The reaction results are listed in Table 1.

[0022] Table 1 Catalyst Evaluation Results Example catalyst 4h reaction yield / % 15h reaction yield / % Example 1 C1 81.9 96.0 Example 2 C2 76.3 93.4 Example 3 C3 67.4 98.7 Example 4 C4 60.8 98.9 Comparative Example 1 C5 13.1 27.2 Comparative Example 2 C6 20.8 48.0 The reaction results in Table 1 show that the catalyst of the present invention can effectively improve the catalyst reaction efficiency and has a high product yield. There is a synergistic effect among the various active components of the catalyst, which has a great influence on the catalytic effect.

Claims

1. A catalyst for synthesizing 1,3-dioxane-2-one, characterized in that: Based on the mass percentage of the catalyst, it includes: 60wt%~90wt% component A, 5wt%-20wt% component B and 5wt%-30wt% component C; wherein component A is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylformamide and urea; component B is one or more of Group IA and IIA carbonates; and component C is 1-butyl-3-methylimidazolium tetrafluoroborate and / or 1-butyl-3-methylimidazolium hexafluorophosphate.

2. The catalyst according to claim 1, characterized in that: It includes 75wt%~90wt% of component A, 5wt%-10wt% of component B, and 10wt%-20wt% of component C.

3. The catalyst according to claim 1, characterized in that: Component B is one or more of lithium carbonate, sodium carbonate, potassium carbonate, cesium carbonate, calcium carbonate, and magnesium carbonate.

4. A method for preparing the catalyst for synthesizing 1,3-dioxane-2-one according to claim 1, characterized in that... The process includes the following: mixing and dissolving component B, component A, and component C to obtain a catalyst.

5. The method according to claim 4, characterized in that: Add component B to component A and stir at 50-70°C for 1-4 hours. Stop heating and cool the solution to below 30°C. Add component C to the solution and stir at 10-30°C for 0.5-2 hours.

6. The use of the catalyst according to any one of claims 1 to 4 in the synthesis of 1,3-dioxane-2-one.

7. The application according to claim 6, characterized in that: A cyclization reaction was carried out using CO2 and 3-chloro-1-propanol as raw materials.

8. The application according to claim 6, characterized in that: The catalyst was added to the reactor, along with acetonitrile and 3-chloro-1-propanol. Pure CO2 was then introduced as the reaction gas to carry out the cyclization reaction.

9. The application according to claim 6, characterized in that: The mass ratio of catalyst, 3-chloro-1-propanol, and solvent is 1~10:10:10~100.

10. The application according to claim 6, characterized in that: The reaction pressure is 0.1-5 MPa, and the reaction temperature is 40-120℃.

Images