A method for preparing 5-formyl-2-furancarboxylic acid
By introducing a protective group and combining Amberlyst15 catalyst and oxidation catalyst I, the problem of unsatisfactory selectivity during HMF oxidation is solved, and the efficient synthesis of high-purity 5-formyl-2-furanformic acid is achieved, with the advantages of mild reaction conditions and convenient operation.
Patent Information
- Application Number
- CN202411719887.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-28
- Publication Date
- 2025-04-08
AI Technical Summary
In the prior art, there are many side reactions and by-products of the aerobic oxidation process of HMF, and the catalytic system has an unsatisfactory selectivity for oxidation, resulting in an unsatisfactory synthesis route of 5-formyl-2-furanformic acid.
By introducing a protecting group, the oxidative selectivity is improved, and the Amberlyst 15 catalyst and the oxidative catalyst I are used to combine the protecting group and the oxidation reaction, and the reaction conditions are adjusted to obtain an ideal synthesis route.
The oxidative selectivity is improved and high-purity 5-formyl-2-furanformic acid is obtained. The reaction conditions are mild and the operation is convenient, and special equipment and precious metal catalysis is required.
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Figure CN119775235A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of biomass resource utilization, and specifically relates to a method for preparing 5-formyl-2-furancarboxylic acid. Background Art
[0002] As a renewable carbon source other than fossil resources, the development and utilization of biomass is an important part of achieving energy sustainability and can provide alternatives to chemicals produced from fossil fuels. Converting carbohydrates into key platform compounds is an important way to convert biomass. Carbohydrates such as 5-hydroxymethylfurfural (HMF), the dehydration product of fructose, are widely used and can be converted into high-value-added chemicals 5-formyl-2-furancarboxylic acid (FFCA) through oxidation, hydrogenation, polymerization and ring-opening reactions of its alcohol, aldehyde and furan rings. FFCA is an important biomaterial with broad application prospects in drug synthesis and chemical intermediate synthesis. Due to the large number of side reactions and by-products in the aerobic oxidation process of HMF, the current catalytic system is not ideal for oxidation selectivity. The oxidation product of HMF, 2,5-furandicarboxaldehyde (DFF), can be synthesized into value-added chemicals such as 5-formyl-2-furancarboxylic acid (FFCA) through oxidation reactions. Therefore, it is necessary to develop and design more reasonable reaction synthesis routes, adjust the starting materials, and introduce protective groups to solve the problem of reaction selectivity, so as to obtain ideal synthesis routes and products. Summary of the invention
[0003] In view of the above problems, the present invention provides a method for preparing 5-formyl-2-furancarboxylic acid, by introducing a protecting group to improve the oxidation selectivity, thereby obtaining a new synthesis process for synthesizing 5-formyl-2-furancarboxylic acid.
[0004] In order to achieve the above object, the technical solution adopted by the present invention is: A method for preparing 5-formyl-2-furancarboxylic acid comprises the following steps: S1: Add a certain proportion of tetrahydrofuran, 2,5-furandicarboxaldehyde and Amberlyst15 catalyst into a reaction vessel, start stirring, set a certain reaction temperature, and slowly drop a protecting group solvent into the reaction system; S2: After the addition is complete, the mixture is stirred and heated for 0.5-24 hours. After the reaction is complete, the mixture is filtered and the filtrate is collected; S3: The filtrate is concentrated under reduced pressure until no obvious fraction exists, methyl tert-butyl ether is added to the solid obtained by concentration, and the mixture is stirred and slurried for a period of time, and then filtered, the filter cake is collected, and transferred to an oven for drying to obtain compound A; S4: adding a certain amount of compound A to another reaction container, adding a certain proportion of water, adding sodium hydroxide, adding an oxidative catalyst I, and then slowly dropping a sodium hypochlorite solution into the reaction system; S5: After the addition is complete, the mixture is stirred and heated for 0.5-24 hours. After the reaction is complete, diatomaceous earth is spread and filtered, and the filtrate is collected to obtain the filtrate of compound B. S6: Add hydrochloric acid dropwise to the filtrate obtained in step S5 and adjust the pH value and then stir, and a large amount of solid precipitates; S7, filtering with suction, collecting the filter cake, transferring it to an oven for drying, and obtaining 5-formyl-2-furancarboxylic acid.
[0005] Further, the protective group solvent is one of methanol, ethanol, and 1,3-propylene glycol, preferably 1,3-propylene glycol. When the protective group solvent is 1,3-propylene glycol, the obtained compound A is 5-(1,3-dioxane-2-yl)furan-2-carboxaldehyde, and the obtained compound B is 5-(1,3-dioxane-2-yl)furan-2-carboxylic acid; when the protective group solvent is methanol, the obtained compound A is 5-(methoxymethyl)furan-2-carboxaldehyde, and the obtained compound B is 5-(methoxymethyl)furan-2-carboxylic acid; when the protective group solvent is ethanol, the obtained compound A is 5-(ethoxymethyl)furan-2-carboxaldehyde, and the obtained compound B is 5-(ethoxymethyl)furan-2-carboxylic acid.
[0006] Furthermore, the reaction temperature in step S1 is 0-65°C.
[0007] Furthermore, in step S1, the mass ratio of 2,5-furandicarboxaldehyde, tetrahydrofuran and Amberlyst 15 catalyst added is 1:4~15:0.05~5.
[0008] Furthermore, in step S3, the stirring and beating time is 1-2 hours, and the drying temperature is 45-60°C.
[0009] Furthermore, in step S4, the mass ratio of compound A, sodium hydroxide and oxidation catalyst I added is 1:0.1~5:0.05~5.
[0010] Furthermore, the oxidation catalyst I is one or more composites of copper oxide, zinc oxide, manganese oxide, cobalt oxide, nickel oxide, iron oxide, aluminum oxide, silicon oxide, lanthanum oxide, cerium oxide, alkali metal oxide, and alkaline earth metal oxide. More preferably, the oxidation catalyst I is one or more composites of copper oxide, cobalt oxide, aluminum oxide, silicon oxide, and manganese oxide.
[0011] Furthermore, in step S4, the mass ratio of the amount of sodium hypochlorite added dropwise to compound A is 1:4.0-20.
[0012] Furthermore, in step S6, the concentration of the hydrochloric acid added dropwise is 0.5-12 mol / L, the pH value is adjusted to 1-3, and the stirring time is 1-24 h.
[0013] Furthermore, in step S7, the oven drying temperature is 45-60°C.
[0014] In the present application, 2,5-furandicarboxaldehyde reacts with alcohol to undergo acetalization reaction, protecting the unilateral aldehyde group, and then oxidizing the unilateral carboxylic acid, and simultaneously adjusting the acid to undergo deacetalization reaction.
[0015] In summary, the present invention proposes that 2,5-furandicarboxaldehyde is subjected to the catalysis of Amberlyst-15, a protecting group (preferably 1,3-propylene glycol, the same below) is introduced to protect the unilateral aldehyde group, and then the unprotected aldehyde group is oxidized with an oxidative catalyst I and sodium hypochlorite under alkaline conditions, and finally the catalyst is removed by solid-liquid separation, and the acid is adjusted for deprotection to precipitate the product 5-formyl-2-furancarboxylic acid. The present invention has the advantages of mild reaction conditions, convenient operation, no need for special equipment, no need for precious metal catalysis, etc. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 The synthetic reaction scheme of the target compound in Example 1 of the present invention is shown in FIG. Figure 2 The synthetic reaction scheme of the target compound of Example 2 of the present invention is shown in FIG. Figure 3 The synthetic reaction scheme of the target compound of Example 3 of the present invention is shown in FIG. Figure 4 This is the H-NMR spectrum of 5-formyl-2-furancarboxylic acid prepared in Example 1 of the present invention. DETAILED DESCRIPTION
[0017] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention. Example 1
[0018] (1) Synthesis of 5-(1,3-dioxane-2-yl)furan-2-carboxaldehyde 100.0 mL of tetrahydrofuran was added to a 250 mL reaction bottle, stirring was started, 10.0 g of 2,5-furandicarboxaldehyde was added, 2.0 g of Amberlyst 15 was added, the reaction temperature was controlled at 25°C, 6.1 g of 1,3-propylene glycol was slowly added dropwise to the reaction bottle, the addition was complete, the reaction was continued for 6 h, the reaction system was filtered, the filtrate was collected, the filtrate was concentrated under reduced pressure until there was no obvious fraction, 30 mL of methyl tert-butyl ether was added, the mixture was stirred for 1 h, suction filtered, the filter cake was collected, and the mixture was transferred to an oven at 45°C for 12 h to obtain 10.7 g of off-white solid; purity 97.2%; 1H NMR (600 MHz,CDCl3) δ 9.63 (s,1H), 7.18 (d, J = 3.6 Hz, 1H),6.61 (d, J= 3.6 Hz, 1H), 5.60 (s, 1H), 4.22 (m, 2H), 3.94 (m, 2H),2.21 (m,1H).1.45 (m, 1H). (2) Synthesis of 5-(1,3-dioxane-2-yl)furan-2-carboxylic acid Add 10.0 g of the above-mentioned dried material 5-(1,3-dioxane-2-yl)furan-2-carboxaldehyde into a 250 mL reaction bottle, add 50 mL of water, add 5.0 g of sodium hydroxide, add 2.0 g of oxidative catalyst I (manganese oxide, cobalt oxide, nickel oxide composite in equal proportions), and slowly drop 41.0 g of sodium hypochlorite solution with 10% effective chlorine into the reaction system; after the dropwise addition is completed, keep warm and stir to react for 3 h. After the reaction is completed, spread diatomaceous earth and filter, and collect the filtrate for the next reaction.
[0019] (3) Synthesis of 5-formyl-2-furancarboxylic acid The filtrate from the previous step was added to a 250 mL reaction bottle, and 6 mol / L hydrochloric acid solution was added dropwise to adjust the pH to 2. The mixture was stirred for 6 h. A large amount of solid was precipitated. The filter cake was collected and transferred to an oven at 45°C for drying for 12 h. 10.7 g of off-white solid was obtained with a purity of 98.1%.
[0020] The synthetic reaction route of related compounds is as follows Figure 1 As shown; Figure 4 The NMR spectrum of 5-formyl-2-furancarboxylic acid prepared in this example is as follows: Figure 4 It can be seen that the chemical shift of the product is consistent with that of the target product. Example 2
[0021] (1) Synthesis of 5-(methoxymethyl)furan-2-carboxaldehyde Add 100.0 mL of tetrahydrofuran to a 250 mL reaction bottle, start stirring, add 10.0 g of 2,5-furandicarboxaldehyde, add 2.0 g of Amberlyst 15, control the reaction temperature at 25°C, slowly add 2.57 g of methanol to the reaction bottle, and react for 48 h. Filter the reaction system, collect the filtrate, and concentrate the filtrate under reduced pressure until there is no fraction, and collect 3.4 g of oily liquid; purity 75.2%.
[0022] (2) Synthesis of 5-(methoxymethyl)furan-2-carboxylic acid Add 3.4 g of the above oily substance 5-(methoxymethyl)furan-2-carboxaldehyde to a 250 mL reaction bottle, add 17 mL of water, add 1.7 g of sodium hydroxide, add 0.68 g of oxidation catalyst I (cobalt oxide), and slowly drop 14.8 g of sodium hypochlorite solution with 10% effective chlorine into the reaction system. After the dropwise addition is completed, heat and stir to react for 3 h; after the reaction is completed, diatomaceous earth is spread and filtered, and the filtrate is collected for the next reaction.
[0023] (3) Synthesis of 5-formyl-2-furancarboxylic acid The filtrate from the previous step was added to a 250 mL reaction bottle, 6 mol / L hydrochloric acid solution was added dropwise, the pH was adjusted to 2, and the mixture was stirred for 6 h. Solid was precipitated and filtered, the filter cake was collected, and the mixture was transferred to an oven and dried at 45°C for 12 h. 1.7 g of off-white solid was obtained, with a purity of 85.1%.
[0024] The synthetic reaction route of related compounds is as follows Figure 2 shown. Example 3
[0025] (1) Synthesis of 5-(ethoxymethyl)furan-2-carboxaldehyde Add 100.0 mL of tetrahydrofuran to a 250 mL reaction bottle, start stirring, add 10.0 g of 2,5-furandicarboxaldehyde, add 2.0 g of Amberlyst 15, control the reaction temperature at 25°C, slowly add 3.7 g of ethanol to the reaction bottle, and react for 48 h. Filter the reaction system, collect the filtrate, and concentrate the filtrate under reduced pressure until there is no fraction, and collect 4.1 g of oily liquid; purity is 67.2%.
[0026] (2) Synthesis of 5-(ethoxymethyl)furan-2-carboxylic acid Add 4.1 g of the above oily substance 5-(ethoxymethyl)furan-2-carboxaldehyde to a 250 mL reaction bottle, add 20.5 mL of water, add 2.05 g of sodium hydroxide, add 0.82 g of oxidation catalyst I (composite of manganese oxide and cobalt oxide in equal proportions), and slowly drop 12.7 g of sodium hypochlorite solution with 10% effective chlorine into the reaction system. After the dropwise addition is completed, heat and stir to react for 3 h. After the reaction is completed, diatomaceous earth is spread and filtered, and the filtrate is collected for the next reaction.
[0027] (3) Synthesis of 5-formyl-2-furancarboxylic acid The filtrate from the previous step was added to a 250 mL reaction bottle, 6 mol / L hydrochloric acid solution was added dropwise, the pH was adjusted to 2, and the mixture was stirred for 6 h. A large amount of solid was precipitated, which was filtered off with suction, and the filter cake was collected and transferred to an oven at 45°C for drying for 12 h. 3.2 g of off-white solid was obtained, with a purity of 66.1%.
[0028] The synthetic reaction route of related compounds is as follows Figure 3 shown.
[0029] It should be noted that the oxidative catalyst I used in the present application can be obtained by conventional catalyst preparation processes, such as co-precipitation, sol-gel, hydrothermal, (reduction) calcination, etc., or it can be a commercially available catalyst that has been commercially used.
[0030] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.
Claims
1. A method for preparing 5-formyl-2-furancarboxylic acid, characterized in that: The steps include: S1: Add a certain proportion of tetrahydrofuran, 2,5-furandicarboxaldehyde and Amberlyst15 catalyst into a reaction vessel, start stirring, set a certain reaction temperature, and slowly drop a protecting group solvent into the reaction system; S2: After the addition is complete, the mixture is stirred and heated for 0.5-24 hours. After the reaction is complete, the mixture is filtered and the filtrate is collected; S3: The filtrate is concentrated under reduced pressure until no obvious fraction exists, methyl tert-butyl ether is added to the solid obtained by concentration, and the mixture is stirred and slurried for a period of time, and then filtered, the filter cake is collected, and transferred to an oven for drying to obtain compound A; S4: adding a certain amount of compound A to another reaction container, adding a certain proportion of water, adding sodium hydroxide, adding oxidation catalyst I, and then slowly adding sodium hypochlorite solution to the reaction system; S5: After the addition is complete, the mixture is stirred and heated for 0.5-24 hours; After the reaction is completed, diatomaceous earth is spread and filtered, and the filtrate is collected to obtain the filtrate of compound B; S6: Add hydrochloric acid dropwise to the filtrate obtained in step S5 and adjust the pH value and then stir, and a large amount of solid precipitates; S7, filtering with suction, collecting the filter cake, transferring it to an oven for drying, and obtaining 5-formyl-2-furancarboxylic acid.
2. A method for preparing 5-formyl-2-furancarboxylic acid according to claim 1, characterized in that: The protective group solvent is one of methanol, ethanol and 1,3-propylene glycol.
3. A method for preparing 5-formyl-2-furancarboxylic acid according to claim 1, characterized in that: The reaction temperature in step S1 is 0-65°C.
4. A method for preparing 5-formyl-2-furancarboxylic acid according to claim 1, characterized in that: In step S1, the mass ratio of 2,5-furandicarboxaldehyde, tetrahydrofuran and Amberlyst 15 catalyst added is 1:4~15:0.05~5.
5. A method for preparing 5-formyl-2-furancarboxylic acid according to claim 1, characterized in that: In step S3, the stirring and beating time is 1-2 hours, and the drying temperature is 45-60°C.
6. A method for preparing 5-formyl-2-furancarboxylic acid according to claim 1, characterized in that: In step S4, the mass ratio of compound A, sodium hydroxide and oxidation catalyst I added is 1:0.1~5:0.05~5.
7. A method for preparing 5-formyl-2-furancarboxylic acid according to claim 1, characterized in that: The oxidation catalyst I is one or a composite of copper oxide, zinc oxide, manganese oxide, cobalt oxide, nickel oxide, iron oxide, aluminum oxide, silicon oxide, lanthanum oxide, cerium oxide, alkali metal oxide, and alkaline earth metal oxide. More preferably, the oxidation catalyst I is one or a composite of copper oxide, cobalt oxide, aluminum oxide, silicon oxide, and manganese oxide.
8. A method for preparing 5-formyl-2-furancarboxylic acid according to claim 6, characterized in that: The mass ratio of the amount of sodium hypochlorite added dropwise in step S4 to compound A is 1:4.0-20.
9. A method for preparing 5-formyl-2-furancarboxylic acid according to claim 1, characterized in that: In step S6, the concentration of hydrochloric acid added dropwise is 0.5-12 mol / L, the pH value is adjusted to 1-3, and the stirring time is 1-24 h.
10. A method for preparing 5-formyl-2-furancarboxylic acid according to claim 1, characterized in that: The oven drying temperature in step S7 is 45-60°C.