Preparation method and application of PMo10V2-at2Br-PIL catalyst

Abstract

The invention belongs to the field of catalyst synthesis, and particularly relates to a preparation method and application of a PMo10V2-2Br-PIL catalyst. The preparation method comprises the following steps: mixing 3, 3 '-methylene bis (1-(bis (4-vinylphenyl) methyl)-1H-imidazole-3-dibromo poly (p-vinylbenzenesulfonic acid) and H5PMo10V2O40 in water according to a certain mass ratio, putting the mixture into a clean beaker, stirring for a certain time at a certain temperature, and filtering to obtain a yellow precipitate; and washing with water for multiple times, and then carrying out vacuum drying at 50 DEG C for 12 hours to finally obtain the yellow solid catalyst. According to the catalyst, fructose can be selectively converted into 2, 5-furandicarboxaldehyde through a one-pot method, and a foundation is laid for application of the catalyst in the aspect of biomass conversion. The method disclosed by the invention inherits the idea of green sustainable development, and the catalyst has a clear molecular structure, so that the research on the catalytic reaction mechanism is facilitated.

Description

Technical Field

[0001] The present invention belongs to the field of catalyst synthesis chemistry, and particularly relates to a preparation method and application of a PMo 10 V2@2Br-PIL catalyst. Technical Background

[0002] With the depletion of fossil fuels and environmental deterioration, renewable energy is considered a promising technical means to alleviate the energy crisis due to its sustainability and renewability. Biorefining is a sustainable method for converting biomass into valuable chemicals and has attracted wide attention. Fructose is an important biomass commonly found in natural fruits (such as figs, dates, mangoes, pears, etc.) with a high content, and is easy to extract or separate from natural products. Fructose can be converted into various fructose-derived products, such as DFF. DFF has a high market value (~10,000 UDS / kg) and can be used as an important intermediate for synthesizing drugs, fungicides, and polymer monomers. The currently feasible synthesis route is mainly through the partial oxidation of HMF (~2000 UDS / kg), and HMF is generally produced by acid-catalyzed reactions of biomass-derived carbohydrates, which is more costly than fructose synthesis. From the perspective of atom economy and large-scale production, it is highly desirable to directly synthesize DFF from inexpensive and abundant fructose in one pot.

[0003] So far, the catalysts for converting fructose to DFF mainly involve chitosan nanofibers, carbon spheres, graphene oxide, or magnesium-aluminum layered double hydroxides, and their catalytic reactions still face challenges such as low selectivity (most < 60%), complex steps, or poor atom efficiency (Adv. Mater. 2021, 33, 2007056; Green Chem. 2015, 17, 4459-4464).

[0004] Polyoxometalates (POMs) are a class of unique inorganic metal-oxygen clusters formed by transition metal elements (such as Mo, W, V, Nb, or Ta, etc.) and oxygen. Due to the fact that their structures can be regulated at the atomic level, they are endowed with properties such as strong acidity, low toxicity, low corrosiveness, and excellent redox ability. They show broad application prospects in many fields such as catalysis, biochemistry, materials science, electrochemistry, etc., especially with great potential in biomass conversion. However, despite the many advantages of POMs, some of their inherent defects, such as relatively low specific surface area, insufficient stability, and difficulty in recycling them in catalytic reactions, still limit their application as catalysts in biomass conversion (such as the one-pot conversion of fructose to 2,5-furandicarboxaldehyde (DFF)). Polymeric ionic liquids (ILs) are a kind of green and sustainable ionic material, which show excellent performance in green catalysis, energy storage, and sensing. There is an ionic interaction between polymeric ionic liquids and POMs, which can achieve the stabilization and dispersion of POMs.

[0005] Based on this, the present invention provides a preparation method of a 3,3'-methylenebis(1-(bis(4-vinylphenyl)methyl)-1H-imidazol-3-yl)dibromopoly(vinylbenzenesulfonic acid) vanadium molybdenum phosphoric acid catalyst (abbreviated as PMo 10 V2@2Br-PIL). SUMMARY OF THE INVENTION

[0006] The object of the present invention is to provide a simple, economical, and recyclable preparation of a 3,3'-methylenebis(1-(bis(4-vinylphenyl)methyl)-1H-imidazol-3-yl)dibromopoly(vinylbenzenesulfonic acid) vanadium molybdenum phosphoric acid catalyst, and to realize a method for the "one-pot" catalytic selective conversion of fructose to 2,5-furandicarboxaldehyde. This method has the advantages of easy operation, high yield, recyclable catalyst, non-toxic and pollution-free.

[0007] The solution of the present invention is a preparation method of a 3,3'-methylenebis(1-(bis(4-vinylphenyl)methyl)-1H-imidazol-3-yl)dibromopoly(vinylbenzenesulfonic acid) vanadium molybdenum phosphoric acid catalyst, and the steps are as follows:

[0008] Sequentially add an ionic liquid 3,3'-methylenebis(1-(bis(4-vinylphenyl)methyl)-1H-imidazol-3-yl)dibromopoly(vinylbenzenesulfonic acid) compound, H5PMo 10 V2O 40 and a certain volume of water into a container, wherein the mass ratio of 3,3'-methylenebis(1-(bis(4-vinylphenyl)methyl)-1H-imidazol-3-yl)dibromopoly(vinylbenzenesulfonic acid):H5PMo 10 V2O 40 is 0.20 - 0.6: 1.0 - 2.0; stir at a certain temperature for a certain time, and then filter;

[0009] Wash with water multiple times and then dry in vacuum at 50 °C for 12 h. The obtained sample is the vanadium molybdenum phosphoric acid catalyst of 3,3'-methylenebis(1-(bis(4-vinylphenyl)methyl)-1H-imidazol-3-dibromo poly(vinylbenzenesulfonic acid)).

[0010] Preferably, the temperature during stirring is 35 o °C to 55 o °C, and the stirring time is 3 to 6 h.

[0011] The product is characterized by infrared, X-ray photoelectron spectroscopy, scanning electron microscopy and high-resolution transmission electron microscopy to obtain accurate information about the catalyst.

[0012] The molecular structure of a 3,3'-methylenebis(1-(bis(4-vinylphenyl)methyl)-1H-imidazol-3-dibromo poly(vinylbenzenesulfonic acid)) vanadium molybdenum phosphoric acid is as follows:

[0013]

[0014] In this compound, the cationic part is the 3,3'-methylenebis(1-(bis(4-vinylphenyl)methyl)-1H-imidazol-3-dibromo poly(vinylbenzenesulfonic acid) cation with a positive charge on the imidazole, and the anion is vanadium molybdenum phosphoric acid. The two form a polyoxometalate ionic liquid-type catalyst through electrostatic attraction, and the structure composition of this compound is determined through infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy and high-resolution transmission electron microscopy.

[0015] The present invention has the following beneficial effects:

[0016] 1. The preparation method is simple and the cost is low, and the catalysts all have clear molecular structures, which is beneficial to the study of the catalytic reaction mechanism.

[0017] 2. The catalyst can achieve high-yield conversion of fructose to DFF and has high selectivity. Description of the Drawings

[0018] Figure 1 It is the infrared spectrum of the catalyst PMo 10 V2@2Br-PIL.

[0019] Figure 2 It is the X-ray photoelectron spectrum of the catalyst PMo 10 V2@2Br-PIL.

[0020] Figure 3 It is the scanning electron microscopy and high-resolution transmission electron microscopy images of the catalyst 3PMo 10 V2@2Br-PIL.

[0021] Figure 4 For the catalyst PMo 10 Mapping diagram of V2@2Br-PIL. Detailed implementation manners

[0022] The present invention will be described in detail below in conjunction with embodiments, but the protection scope is not limited thereby. The experimental methods in the following embodiments are all conventional methods unless otherwise specified, and the materials, reagents, etc. used in the following embodiments can be obtained from commercial channels unless otherwise specified.

[0023] Example 1:

[0024] In a clean beaker, 3,3'-methylenebis(1-(bis(4-vinylphenyl)methyl)-1H-imidazol-3-ium dibromide poly(p-vinylbenzenesulfonic acid) (0.5 g) and H5PMo 10 V2O 40 (1.5 g) were successively added and mixed with H2O (30 mL), stirred, and stirred for 6 h under the condition of 45 o °C to obtain a yellow precipitate, which was washed three times with 20 mL of distilled water to obtain a yellow solid catalyst with a yield of about 75%.

[0025] Example 2:

[0026] In a clean beaker, 3,3'-methylenebis(1-(bis(4-vinylphenyl)methyl)-1H-imidazol-3-ium dibromide poly(p-vinylbenzenesulfonic acid) (0.4 g) and H5PMo 10 V2O 40 (1.5 g) were successively added and mixed with H2O (30 mL), stirred, and stirred for 6 h under the condition of 25 o °C to obtain a yellow precipitate, which was washed three times with 20 mL of distilled water to obtain a yellow solid catalyst with a yield of about 41%.

[0027] Example 3:

[0028] In a clean beaker, 3,3'-methylenebis(1-(bis(4-vinylphenyl)methyl)-1H-imidazol-3-ium dibromide poly(p-vinylbenzenesulfonic acid) (0.3 g) and H5PMo 10 V2O 40 (1.5 g) were successively added and mixed with H2O (30 mL), stirred, and stirred for 4 h under the condition of 35 o °C to obtain a yellow precipitate, which was washed three times with 20 mL of distilled water to obtain a yellow solid catalyst with a yield of about 37%.

[0029] Example 4:

[0030] In a clean beaker, add 3,3'-methylenebis(1-(bis(4-vinylphenyl)methyl)-1H-imidazol-3-ium dibromide poly(vinylbenzenesulfonic acid)) (0.5 g) and H5PMo 10 V2O 40 (1.3 g) and mix with H2O (30 mL), stir, and stir at 40 o °C for 5 h to obtain a yellow precipitate, wash it three times with 20 mL of distilled water to obtain a yellow solid catalyst with a yield of about 51%.

[0031] Example 5:

[0032] In a clean beaker, add 3,3'-methylenebis(1-(bis(4-vinylphenyl)methyl)-1H-imidazol-3-ium dibromide poly(vinylbenzenesulfonic acid)) (0.5 g) and H5PMo 10 V2O 40 (1.2 g) and mix with H2O (30 mL), stir, and stir at 50 o °C for 5 h to obtain a yellow precipitate, wash it three times with 20 mL of distilled water to obtain a yellow solid catalyst with a yield of about 45%.

[0033] Example 6:

[0034] In a clean beaker, add 3,3'-methylenebis(1-(bis(4-vinylphenyl)methyl)-1H-imidazol-3-ium dibromide poly(vinylbenzenesulfonic acid)) (0.5 g) and H5PMo 10 V2O 40 (1.6 g) and mix with H2O (30 mL), stir, and stir at 50 o °C for 6 h to obtain a yellow precipitate, wash it three times with 20 mL of distilled water to obtain a yellow solid catalyst with a yield of about 74%.

[0035] Example 7:

[0036] In a clean beaker, add 3,3'-methylenebis(1-(bis(4-vinylphenyl)methyl)-1H-imidazol-3-ium dibromide poly(vinylbenzenesulfonic acid)) (0.5 g) and H5PMo 10 V2O 40 (2.0 g) and mix with H2O (30 mL), stir, and stir at 30 o °C for 5 h to obtain a yellow precipitate, wash it three times with 20 mL of distilled water to obtain a yellow solid catalyst with a yield of about 61%.

[0037] Test Example 1:

[0038] PMo 10 Application example of selective conversion of fructose to 2,5-furandicarboxaldehyde by V2@2Br-PIL is as follows:

[0039] 1 mmol of fructose, 30 mg of catalyst and 5 mL of DMSO were added into a reactor, 1.5 MPa of O2 was introduced, heated to 150 °C, stirred for 10 h, the reaction mixture was cooled to room temperature, filtered through a sintered funnel and extracted with ethyl acetate, washed with brine, dried over Na2SO4 and the solvent was removed by evaporation under reduced pressure at 50 °C. The crude product was purified by silica gel column chromatography with a yield of 92%. The PMo after the reaction 10 The V2@2Br-PIL catalyst was dried in air and could be used for the next cycle experiment of selective conversion of fructose to 2,5-furandicarboxaldehyde.

[0040] Of course, the above embodiments of the present invention are only examples for illustrating the present invention, rather than limitations on the specific embodiments of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made on the basis of the above examples. It is impossible to give detailed examples of all the embodiments here. Any obvious changes or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A PMo 10 The preparation method of V2@2Br-PIL catalyst is characterized in that: The steps are as follows: ionic liquid 3,3'-methylenebis(1-(bis(4-vinylphenyl)methyl)-1H-imidazole-3-dibromopoly(p-vinylbenzenesulfonic acid) compound, H5PMo 10 V2O 40 and a certain volume of water, wherein 3,3'-methylenebis(1-(bis(4-vinylphenyl)methyl)-1H-imidazole-3-dibromopoly(p-vinylbenzenesulfonic acid): H5PMo 10 V2O 40 The mass ratio is 0.20 ~ 0.6: 1.0~2.0; stir at a certain temperature for a certain time and filter; After washing with water for several times, the sample was dried under vacuum at 50 °C for 12 h, and the obtained sample was 3,3'-methylenebis(1-(bis(4-vinylphenyl)methyl)-1H-imidazole-3-dibromopoly(p-vinylbenzenesulfonate)vanadium molybdenumphosphoric acid catalyst.

2. The preparation method according to claim 1, characterized in that: The stirring temperature is 35 o C~55 o C, stirring time is 3~6h.

3. Use of the catalyst obtained by the preparation method according to any one of claims 1 to 2 in the selective conversion of fructose into 2,5-furandicarboxaldehyde.

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