DMF (Dimethyl Formamide)-based heteropolyacid synergistic catalysis system as well as preparation method and application thereof

Abstract

The invention belongs to the field of polymer catalysis, and discloses a DMF (Dimethyl Formamide)-based heteropolyacid synergistic catalysis system as well as a preparation method and application thereof. The method comprises the following steps: adding sodium molybdate and disodium hydrogen phosphate into deionized water, adjusting the pH value to 2-3, then adding sodium metavanadate, heating and stirring at 95-100 DEG C, cooling at room temperature, and then adding diethyl ether and a sulfuric acid solution until an upper diethyl ether phase becomes light yellow from colorless; and drying the lowermost layer phase yellow oily substance, grinding and drying to obtain H5PMo10V2O40, and adding the H5PMo10V2O40 into a DMF (Dimethyl Formamide) solvent to prepare the DMF-based heteropolyacid synergistic catalysis system. According to the method, DMF is used as a solvent, the D-fructose is catalytically cracked in oxygen through a one-step method to be converted into DFF, gas does not need to be switched in the reaction process, and the prepared catalytic system is excellent in catalytic benefit, can be recycled, saves manpower and material resources in the catalytic process, is low in equipment requirement and can be suitable for reactions such as catalytic cracking of biomass.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer catalysis, and more specifically, relates to a DMF-based heteropoly acid synergistic catalytic system and a preparation method and application thereof. Background Art

[0002] The depletion of fossil resources and global warming issues have aroused great interest in renewable and sustainable fuel and chemical alternatives, and lignocellulose is one of the most abundant resources on earth and a high-value-added material that can be found everywhere. It can be a substitute for petroleum-based chemicals because it can be converted into other high-value-added small molecule compounds through fermentation, gasification, and thermal cracking. In the past two decades, various methods have been developed for the oxidation of biomass into various carbohydrates.

[0003] D-fructose is one of the two most widely used hexoses obtained from the cracking of lignocellulose. It plays an important role in the life activities of animals and plants and is widely present in the bodies of animals and plants. Therefore, the preparation of high value-added small molecule compounds by using the characteristics of D-fructose, which is widely available, easy to obtain and environmentally friendly, has a high application prospect and is green and sustainable. The small molecule compounds obtained do not contain elements such as S, N and heavy metal elements, and have no toxic volatiles. In the past decade, scientists have paid more and more attention to the cracking and transformation of hexose, and applied it to the preparation of high value-added small molecule compounds. Among them, it can be further oxidized to obtain 2,5-diformylfuran (DFF). DFF has become an important industrial synthesis intermediate with high application value. It is widely used in the synthesis of diamines and polymeric Schiff bases, as well as pharmaceutical intermediates and antibacterial agents. It is also widely used in the synthesis of biomass-based new resins and polyols. At the same time, it can be further catalyzed to prepare 2,5-furandicarboxylic acid, and can also be used as a raw material to synthesize biodegradable plastics. It has extremely high research and application value in replacing petroleum-based plastics.

[0004] There are currently two ways to split D-fructose into DFF: one is to prepare D-fructose through the HMF intermediate using a two-step method; the operation efficiency is not high, and the reaction conditions and even the catalyst need to be changed in the middle, which consumes manpower and material resources while pursuing the reaction yield, and even requires additional replacement of the reaction vessel, which is not suitable for industrial production. The other is to directly synthesize it through a one-step method. The reaction system is required to exhibit strong dehydration and oxidation properties, and can successively promote the dehydration of D-fructose and the immediate oxidation of the intermediate, which makes the selection of the catalytic system particularly important. At present, DMSO is mostly used as a solvent, but the DMSO solvent has a high boiling point and can dissolve most organic matter, which is not conducive to the separation of the product DFF in future industrial production. Therefore, developing a catalytic system that meets the above requirements is currently the key to the industrial production of DFF by splitting D-fructose. Summary of the invention

[0005] In order to solve the above-mentioned shortcomings of the prior art, such as the difficulty in synthesis, low catalytic efficiency, and difficulty in catalyst recovery, the present invention provides a method for preparing a heteropolyacid synergistic catalyst based on a DMF solvent. The method comprises DMF as a solvent and a heteropolyacid as a catalyst, and a heteropolyacid catalytic system based on DMF as a solvent is prepared, and the catalytic effect is excellent, the preparation is simple, and the catalyst can be recycled.

[0006] Another object of the present invention is to provide a heteropolyacid synergistic catalytic system prepared by the above method.

[0007] Another object of the present invention is to provide an application of the above heteropolyacid synergistic catalytic system.

[0008] The purpose of the present invention is achieved through the following technical solutions:

[0009] A method for preparing a DMF-based heteropolyacid synergistic catalytic system comprises the following specific steps:

[0010] S1. Sodium molybdate and disodium hydrogen phosphate are added to deionized water and stirred evenly, the pH value is adjusted to 2 to 3 with sulfuric acid solution, and then sodium metavanadate is added, heated and stirred at 95 to 100 ° C, and then cooled at room temperature;

[0011] S2. Ether was added to the reaction system, and sulfuric acid solution was added again until the upper ether phase changed from colorless to light yellow;

[0012] S3. The bottom layer of yellow oil was taken out through a separatory funnel, and the oil was dried under vacuum, ground and dried at 50 to 60 ° C to obtain a heteropoly acid powder H5PMo. 10 V2O 40 , and added it into N,N-dimethylformamide (DMF) solvent to prepare a DMF-based heteropolyacid synergistic catalytic system.

[0013] Preferably, the sulfuric acid solution in steps S1 and S2 is water and sulfuric acid in a volume ratio of 1: (1 to 1.2).

[0014] Preferably, the molar ratio of sodium molybdate, disodium hydrogen phosphate and sodium metavanadate in step S1 is 0.1:(0.0095-0.01):(0.019-0.02); the volume ratio of the total mole of sodium molybdate, disodium hydrogen phosphate and sodium metavanadate to deionized water is (0.11-0.12) mol:100 mL.

[0015] Preferably, the stirring time in step S1 is 1 to 1.5 hours; and the drying time in step S3 is 5 to 7 hours.

[0016] A DMF-based heteropolyacid synergistic catalytic system is prepared by the method.

[0017] The application of the DMF-based heteropolyacid synergistic catalytic system in the field of catalytic cracking of biomass.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The preparation of the present invention has low requirements on equipment and is easy to operate. The product is easier to separate than the traditional reaction system, saving manpower and material resources.

[0020] 2. The heteropolyacid catalytic system of the present invention is mainly composed of a heteropolyacid catalyst and DMF as a solvent. The catalytic system has excellent catalytic efficiency and can be recycled. The catalytic process saves manpower and material resources, and the product has high catalytic activity and high catalytic efficiency.

[0021] 3. The present invention uses N,N-dimethylformamide with a relatively low boiling point as a solvent, and catalytically cracks D-fructose in oxygen to convert it into DFF in a one-step method, with a conversion rate of more than 98%. It gets rid of the reaction system of traditional Mo-containing catalysts and DMSO solvents, and there is no need to switch gases during the reaction. It can be applied to reactions such as catalytic cracking of biomass.

[0022] Description of the attached figure

[0023] Figure 1 Is the structural formula of the product DFF of the present invention;

[0024] Figure 2 The schematic diagram of the synthetic route of the present invention is as follows;

[0025] Figure 3 is the liquid chromatogram of Application Example 1;

[0026] Figure 4 is the liquid chromatogram of Application Example 2;

[0027] Figure 5is the liquid chromatogram of Application Example 3;

[0028] Figure 6 is the liquid chromatogram of Application Example 4;

[0029] Figure 7 is the liquid chromatogram of Application Example 5;

[0030] Figure 8 is the liquid chromatogram of Application Example 6;

[0031] Fig. 9 is the liquid chromatogram of Application Example 7;

[0032] Fig.10 is the liquid chromatogram of Application Example 8;

[0033] Fig.11 is the liquid chromatogram of Application Example 9;

[0034] Fig.12 is the liquid chromatogram of Application Example 10;

[0035] Fig.13 is the liquid chromatogram of Application Example 11;

[0036] Fig.14 It is the liquid chromatogram of Comparative Example 1;

[0037] Fig.15 It is the liquid chromatogram of Comparative Example 2;

[0038] Fig.16 This is the liquid chromatogram of Comparative Example 3. DETAILED DESCRIPTION

[0039] The content of the present invention is further described below in conjunction with specific examples, but it should not be construed as limiting the present invention. If not specifically indicated, the technical means used in the examples are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0040] Example 1

[0041] 1. Add 0.1 mol sodium molybdate and 0.01 mol disodium hydrogen phosphate into 100 mL deionized water and stir evenly. Slowly add sulfuric acid solution (H2O and H2SO4 with a volume ratio of 1:1) into the reaction system, adjust the pH value to 2-3, then add 0.02 mol sodium metavanadate, stir and heat at 100°C for 1 hour, and then cool at room temperature.

[0042] 2. Add 30 mL of ether to the reaction system and adjust the pH value of the reaction system with sulfuric acid solution (H2O and H2SO4 with a volume ratio of 1:1) until the upper ether phase changes from colorless to light yellow. Finally, three phases are formed in the reaction system, among which the yellow oily substance in the bottom phase is the etherification product of heteropolyacid. Separate it and vacuum dry it at 50°C for 6 hours to obtain heteropolyacid powder H5PMo 10 V2O 40 After grinding, H5PMo containing 0.01mmol Mo element was obtained. 10 V2O 40 The powder was added to 10 mL of DMF to obtain a heteropolyacid catalyst system, such as Figure 2 shown.

[0043] Example 2

[0044] 1. Add 0.1 mol sodium molybdate and 0.01 mol disodium hydrogen phosphate to 100 mL deionized water and stir evenly. Slowly add sulfuric acid solution (H2O and H2SO4 with a volume ratio of 1:1) to the reaction system, adjust the pH value to 2-3, then add 0.02 mol sodium metavanadate, stir and heat at 100°C for 1 hour, and then cool at room temperature.

[0045] 2. Add 30 mL of ether to the reaction system and adjust the pH value of the reaction system with sulfuric acid solution (H2O and H2SO4 in a volume ratio of 1:1) until the upper ether phase changes from colorless to light yellow. Finally, three phases are formed in the reaction system, among which the yellow oily substance in the bottom phase is the etherification product of heteropolyacid. Separate it and vacuum dry it at 50°C for 6 hours to obtain heteropolyacid powder H5PMo 10 V2O 40 After grinding, H5PMo containing 0.005mmol Mo element was obtained. 10 V2O 40 The powder was added into 10 mL of DMF to obtain a heteropolyacid catalyst system.

[0046] Example 3

[0047] 1. Add 0.1 mol sodium molybdate and 0.01 mol disodium hydrogen phosphate to 100 mL deionized water and stir evenly. Slowly add sulfuric acid solution (H2O:H2SO4 with a volume ratio of 1:1) to the reaction system and adjust the pH value to 2-3. Then add 0.02 mol sodium metavanadate to the solution, stir and heat at 100°C for 1 hour, and then cool at room temperature.

[0048] 2. Add 30 mL of ether to the reaction system and adjust the pH value of the reaction system with sulfuric acid solution (H2O:H2SO4 with a volume ratio of 1:1) until the upper ether phase changes from colorless to light yellow. Finally, three phases are formed in the reaction system, among which the yellow oily substance in the bottom phase is the etherification product of heteropolyacid. Separate it and vacuum dry it at 50℃ for 6h to obtain heteropolyacid powder H5PMo 10 V2O 40 After grinding, H5PMo containing 0.015mmol Mo element was obtained. 10 V2O 40 The powder was added into 10 mL of DMF to obtain a heteropolyacid catalyst system.

[0049] Example 4

[0050] 1. Add 0.1 mol sodium molybdate and 0.01 mol disodium hydrogen phosphate to 100 mL deionized water and stir evenly. Slowly add sulfuric acid solution with a volume ratio of 1:1 (H2O:H2SO4) to the reaction system, adjust the pH value to 2-3, then add 0.02 mol sodium metavanadate to the solution, stir and heat at 100°C for 1 hour, and then cool at room temperature.

[0051] 2. Add 30 mL of ether to the reaction system and adjust the pH value of the reaction system with sulfuric acid solution (H2O and H2SO4 in a volume ratio of 1:1) until the upper ether phase changes from colorless to light yellow. Finally, three phases are formed in the reaction system, among which the yellow oily substance in the bottom phase is the etherification product of heteropolyacid. Separate it and vacuum dry it at 50°C for 6 hours to obtain heteropolyacid powder H5PMo 10 V2O 40 After grinding, H5PMo containing 0.02mmol Mo element was obtained. 10 V2O 40 The powder was added into 10 mL of DMF to obtain a heteropolyacid catalyst system.

[0052] Example 5

[0053] 1. Add 0.1 mol sodium molybdate and 0.01 mol disodium hydrogen phosphate to 100 mL deionized water and stir evenly. Slowly add sulfuric acid solution (H2O and H2SO4 with a volume ratio of 1:1) to the reaction system to adjust the pH value to 2-3. Then add 0.009 mol sodium metavanadate to the solution and heat with stirring at 100°C for 1 hour. Then cool at room temperature.

[0054] 2. Add 30 mL of ether to the reaction system and adjust the pH value of the reaction system with sulfuric acid solution (H2O and H2SO4 with a volume ratio of 1:1) until the upper ether phase changes from colorless to light yellow. Finally, three phases are formed in the reaction system, among which the yellow oily substance in the bottom phase is the etherification product of heteropolyacid. It is separated and dried in vacuum at 50°C for 6 hours to obtain heteropolyacid powder H5PMo 11 VO 40 After grinding, H5PMo containing 0.01mmol Mo element was obtained. 10 V2O 40 The powder was added into 10 mL of DMF to obtain a heteropolyacid catalyst system.

[0055] Application Example 1

[0056] 360 mg (2 mmol) of D-fructose and the heteropolyacid catalyst system of Example 1 were added to a high-pressure reactor at the same time, 1 MPa of oxygen was introduced, and the reaction was stirred at 120° C. (speed was 600 rpm) for 3 h. After the reaction was completed, the residual liquid volume of the reaction system was accurately measured, and then 1 mL of the liquid sample was measured for liquid chromatography characterization. Figure 3 shown.

[0057] Application Example 2

[0058] 360 mg (2 mmol) of D-fructose and the heteropolyacid catalyst system of Example 1 were added to a high-pressure reactor at the same time, 1 MPa of oxygen was introduced, and the reaction was stirred at 130° C. (speed of 600 rpm) for 3 h. After the reaction was completed, the residual liquid volume of the reaction system was accurately measured, and then 1 mL of the liquid sample was measured for liquid chromatography characterization. Figure 4 shown.

[0059] Application Example 3

[0060] 360 mg (2 mmol) of D-fructose and the heteropolyacid catalyst system of Example 1 were added to a high-pressure reactor at the same time, 1 MPa of oxygen was introduced, and the reaction was stirred at 140° C. (speed was 600 rpm) for 3 h. After the reaction was completed, the residual liquid volume of the reaction system was accurately measured, and then 1 mL of the liquid sample was measured for liquid chromatography characterization. Figure 5 shown.

[0061] Application Example 4

[0062] 360 mg (2 mmol) of D-fructose and the heteropolyacid catalyst system of Example 1 were added to a high-pressure reactor at the same time, 1 MPa of oxygen was introduced, and the reaction was stirred at 150° C. (speed was 600 rpm) for 3 h. After the reaction was completed, the residual liquid volume of the reaction system was accurately measured, and then 1 mL of the liquid sample was measured for liquid chromatography characterization. Figure 6shown.

[0063] Application Example 5

[0064] 360 mg (2 mmol) of D-fructose and the heteropolyacid catalyst system of Example 1 were added to a high-pressure reactor at the same time, 1 MPa of oxygen was introduced, and the reaction was stirred at 160° C. (speed was 600 rpm) for 3 h. After the reaction was completed, the residual liquid volume of the reaction system was accurately measured, and then 1 mL of the liquid sample was measured for liquid chromatography characterization. Figure 7 shown.

[0065] Application Example 6

[0066] 360 mg (2 mmol) of D-fructose and the heteropolyacid catalyst system of Example 1 were added to a high-pressure reactor at the same time, 1 MPa of oxygen was introduced, and the reaction was stirred at 140° C. (speed was 600 rpm) for 1 h. After the reaction was completed, the residual liquid volume of the reaction system was accurately measured, and then 1 mL of the liquid sample was measured for liquid chromatography characterization. Figure 8 shown.

[0067] Application Example 7

[0068] 360 mg (2 mmol) of D-fructose and the heteropolyacid catalyst system of Example 1 were added to a high-pressure reactor at the same time, 1 MPa of oxygen was introduced, and the reaction was stirred at 140° C. (speed was 600 rpm) for 2 h. After the reaction was completed, the residual liquid volume of the reaction system was accurately measured, and then 1 mL of the liquid sample was measured for liquid chromatography characterization. Fig. 9 shown.

[0069] Application Example 8

[0070] 360 mg (2 mmol) of D-fructose and the heteropolyacid catalyst system of Example 1 were added to a high-pressure reactor at the same time, 1 MPa of oxygen was introduced, and the reaction was stirred at 140° C. (speed was 600 rpm) for 4 h. After the reaction was completed, the residual liquid volume of the reaction system was accurately measured, and then 1 mL of the liquid sample was measured for liquid chromatography characterization. Fig.10 shown.

[0071] Application Example 9

[0072] 360 mg (2 mmol) of D-fructose and the heteropolyacid catalyst system prepared in Example 2 were added to a high-pressure reactor at the same time, 1 MPa of oxygen was introduced, and the reaction was stirred at 140° C. (speed was 600 rpm) for 3 h. After the reaction was completed, the residual liquid volume of the reaction system was accurately measured, and then 1 mL of the liquid sample was measured for liquid chromatography characterization. Fig.11 shown.

[0073] Application Example 10

[0074] 360 mg (2 mmol) of D-fructose and the heteropolyacid catalyst system prepared in Example 3 were added to a high-pressure reactor at the same time, 1 MPa of oxygen was introduced, and the reaction was stirred at 140° C. (speed was 600 rpm) for 3 h. After the reaction was completed, the residual liquid volume of the reaction system was accurately measured, and then 1 mL of the liquid sample was measured for liquid chromatography characterization. Fig.12 shown.

[0075] Application Example 11

[0076] 360 mg (2 mmol) of D-fructose and the heteropolyacid catalyst system prepared in Example 4 were added to a high-pressure reactor at the same time, 1 MPa of oxygen was introduced, and the reaction was stirred at 140° C. (speed of 600 rpm) for 3 h. After the reaction was completed, the residual liquid volume of the reaction system was accurately measured, and then 1 mL of the liquid sample was measured for liquid chromatography characterization. Fig.13 shown.

[0077] Comparative Example 1

[0078] 360 mg (2 mmol) of D-fructose was added to a high-pressure reactor, 1 MPa of oxygen was introduced, and the reaction was stirred at 140°C (speed of 600 rpm) for 3 h. After the reaction was completed, the residual liquid volume of the reaction system was accurately measured, and then 1 mL of liquid sample was measured for liquid chromatography characterization, such as Fig.14 shown.

[0079] Comparative Example 2

[0080] 360 mg (2 mmol) of D-fructose and the heteropolyacid catalyst system prepared in Example 5 were added to a high-pressure reactor at the same time, 1 MPa of oxygen was introduced, and the reaction was stirred at 140° C. (speed was 600 rpm) for 3 h. After the reaction was completed, the residual liquid volume of the reaction system was accurately measured, and then 1 mL of the liquid sample was measured for liquid chromatography characterization. Fig.15 shown.

[0081] Comparative Example 3

[0082] 360 mg (2 mmol) of D-fructose and 0.083 mmol of phosphomolybdic acid were added simultaneously to a high-pressure reactor containing 10 mL of N,N-dimethylformamide (DMF), 1 MPa of oxygen was introduced, and the reaction was stirred at 140 ° C (speed of 600 rpm) for 3 h. After the reaction was completed, the residual liquid volume of the reaction system was accurately measured, and then 1 mL of liquid sample was measured for liquid chromatography characterization, such as Fig.16 shown.

[0083] Table 1 Catalytic activity of the catalytic systems of Application Examples 1-11 and Comparative Examples 1-3 for catalytic cracking of D-fructose into 2,5-diformylfuran (DFF)

[0084]

[0085]

[0086] Table 1 shows the catalytic activity of the catalytic systems of Application Examples 1-11 and Comparative Examples 1-3 in catalytic cracking of D-fructose into 2,5-diformylfuran (DFF). As shown in Table 1, compared with Comparative Example 1, the conversion rates of D-fructose in all reactions using the catalysts were improved, and the conversion rates of Application Examples 1-11 were greater than 98%, with most of the products mainly concentrated in DFF (structured as Figure 1 In the reaction conditions of Example 3, the maximum yield of DFF reached 60.2% under the conditions of Example 1 as the catalytic system. This shows that the DMF-based heteropoly acid synergistic catalytic system of the present invention has an excellent catalytic effect on D-fructose and can efficiently promote its reaction.

[0087] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for preparing a DMF-based heteropolyacid synergistic catalytic system, characterized in that: The specific steps include: S1. Sodium molybdate and disodium hydrogen phosphate are added to deionized water and stirred evenly, the pH value is adjusted to 2 to 3 with sulfuric acid solution, and then sodium metavanadate is added, heated and stirred at 95 to 100 ° C, and then cooled at room temperature; S2. Ether was added to the reaction system, and sulfuric acid solution was added again until the upper ether phase changed from colorless to light yellow; S3. The bottom layer of yellow oil was taken out through a separatory funnel, and the oil was dried under vacuum, ground and dried at 50 to 60 ° C to obtain a heteropoly acid powder H5PMo. 10 V2O 40 , and added it into DMF solvent to prepare a DMF-based heteropolyacid synergistic catalytic system.

2. The method for preparing the heteropolyacid synergistic catalytic system based on DMF solvent according to claim 1, characterized in that: The sulfuric acid solution in steps S1 and S2 is water and sulfuric acid in a volume ratio of 1: (1 to 1.2).

3. The preparation method of the heteropolyacid synergistic catalytic system based on DMF solvent according to claim 1, characterized in that, The molar ratio of sodium molybdate, disodium hydrogen phosphate and sodium metavanadate in step S1 is 0.1:(0.0095-0.01):(0.019-0.02); the volume ratio of the total mole of sodium molybdate, disodium hydrogen phosphate and sodium metavanadate to deionized water is (0.11-0.12) mol:100 mL.

4. The method for preparing the heteropolyacid synergistic catalytic system based on DMF solvent according to claim 1, characterized in that: The stirring time in step S1 is 1 to 1.5 hours; the drying time in step S3 is 5 to 7 hours.

5. A DMF-based heteropolyacid synergistic catalytic system, characterized in that: The heteropolyacid synergistic catalytic system is prepared by the method described in any one of claims 1-4.

6. Application of the DMF-based heteropolyacid synergistic catalytic system according to claim 5 in the field of catalytic cracking of biomass.

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