Process for preparing supported heterogeneous composite heteropolyacid catalysts and use thereof

Abstract

The application discloses a preparation method and application of a supported heterogeneous composite heteropolyacid catalyst, and comprises the following steps: 1) preparing a catalyst carrier solution for standby; 2) adding a metal catalytic center reagent and a heteropolyacid into a three-necked flask containing deionized water, and carrying out a reaction under the condition of heating and stirring; after the reaction is completed and the reaction product is cooled to room temperature, the product is filtered and centrifuged to obtain a heterogeneous composite heteropolyacid catalyst precursor; 3) adding the catalyst carrier solution and a solvent I into the heterogeneous composite heteropolyacid catalyst precursor, uniformly mixing, filtering out the mixed solvent, obtaining a solid sample, and then calcining the solid sample; after the calcination is completed, the calcined product is cooled to room temperature, and then washed and dried, so that the catalyst to be prepared is obtained; the catalyst has higher reaction selectivity, lower reaction condition requirement, and more moderate reaction condition; and the catalytic effect of the catalyst is basically unchanged after multiple cycles.

Description

TECHNICAL FIELD

[0001] The present application relates to a preparation method of chemicals, in particular to a preparation method of a supported heterogeneous composite heteropolyacid catalyst and application thereof. BACKGROUND

[0002] The social modernization process is generally considered to overlap with the industrialization process. Generally, industrial production improves efficiency and expands capacity, which still cannot do without fossil energy. However, the contradiction between the speed of global industrialization and the accumulation speed of fossil energy in nature is gradually intensified. In addition, fossil energy also introduces a large amount of free carbon compounds into nature, which destroys the carbon cycle of the earth's ecological system and threatens the living environment and quality of human beings. Bio-refining opens up a new path for the balanced development of energy and economy, and the development and use of furan compounds gradually become the research focus in the bio-refining process.

[0003] Among them, hydroxymethylfurfural (HMF) can form various derivatives due to its multiple functional groups, and therefore is defined as a high-value platform compound together with other 13 compounds. HMF mainly includes 5-hydroxymethylfurfural (5-HMF) and isomer 4-hydroxymethylfurfural (4-HMF), and their structural formulas are as follows:

[0004]

[0005] The typical preparation method of 5-HMF is dehydration of hexose under acidic conditions, and then 5-HMF can be further hydrogenated into biomass fuel 2,5-dimethylfuran (2,5-DMF), oxidized into polymer polyethylene glycol 2,5-furandicarboxylate (2,5-PEF) structural monomer 2,5-furandicarboxylic acid (2,5-FDCA) and the like; 4-HMF can be synthesized by glycerol and its derivatives glycerol aldehyde (GLYD) and dihydroxyacetone (DHA). 4-HMF can not only be converted into biomass fuel 2,4-DMF, but also can synthesize drug cantharidin, and 2,4-FDCA formed by oxidation of cantharidin forms 2,4-PEF, which has a special asymmetric structure and increases the amorphous state after annealing, and can form nematic liquid crystal molecules, which provides a new direction for liquid crystal materials and can also consume.

[0006] For the preparation of 4-HMF, the conventional catalysts generally have the disadvantages of poor selectivity and low yield. Although ionic liquids can significantly improve the yield of HMF. However, similar to 5-HMF, it is difficult to recover and purify 4-HMF in ionic liquids and the like, and in addition, ionic liquids generally have the problems of high price, difficult to be reused for many times, and generally high toxicity, which greatly increases the comprehensive cost of subsequent treatment.

[0007] Heteropoly acid is a new type of solid catalyst with adjustable structure, and a typical heteropoly acid includes a central atom (usually a heteroatom) and a coordination atom (usually a transition metal atom), which are combined in space by an oxygen atom bridge to form a polyoxometalate complex, and generally have a stable structure, and can load different molecules and atoms to form new catalysts. A typical heteropoly acid catalyst loads acidic and oxidative molecules or atoms, and can be used as an acid catalytic oxidation catalyst or a bifunctional catalyst, and fully exhibits catalytic activity during the reaction. Due to the special structure and the diversity of atoms contained in the heteropoly acid, the degree of surface charge delocalization is relatively high, and the heteropoly acid not only can exhibit strong Bronsted acidity in a solvent, but also can accept electrons to play a Lewis acid role.

[0008] In addition, due to its solubility in polar solvents and unique reaction field (referred to as "pseudo-liquid phase behavior"), it can be used not only in a homogeneous catalytic system, but also in a heterogeneous catalytic system. In addition, the atom combination of the heteropoly acid is flexible, and the combination of atoms in the heteropoly acid can be adjusted under different conditions and requirements to obtain a target catalytic effect.

[0009] Therefore, according to the above problems, it is of great practical significance to develop a catalyst that can be reused and easily separated for the stable production of 4-HMF, the development of new uses of HMF, and the construction of a biomass-derived industry chain with HMF series products as the core. SUMMARY

[0010] In view of the problems existing in the prior art, the purpose of the present application is to provide a preparation method of a supported heterogeneous composite heteropoly acid catalyst and its application. The catalyst of the present application has basically unchanged catalytic effect after multiple cycles, and the reaction conditions are easy to achieve when the catalyst is used to prepare 4-hydroxymethylfurfural, and the reaction system is simple.

[0011] The technical scheme of the present application is as follows:

[0012] The preparation method of the supported heterogeneous composite heteropoly acid catalyst comprises the following specific steps:

[0013] 1) Prepare a catalyst carrier solution for standby use;

[0014] 2) Add the metal catalytic center reagent and the heteropoly acid into a three-necked flask containing deionized water, and perform a reaction under the condition of heating and stirring. After the reaction is completed and the reaction system is cooled to room temperature, the material after the reaction is subjected to filtration and centrifugation to obtain a heterogeneous composite heteropoly acid catalyst precursor;

[0015] 3) adding the catalyst carrier solution prepared in step 1) and solvent one into the heterogeneous composite heteropolyacid catalyst precursor obtained in step 2), mixing uniformly, filtering out the mixed solvent, obtaining a solid sample, then calcining the solid sample, after the calcination is completed, after cooling to room temperature, taking out the calcined material, and then washing and drying the calcined material, thereby obtaining the prepared catalyst.

[0016] Further, the specific process of step 1) is as follows: adding the catalyst carrier into a beaker containing the organic solvent, and then ultrasonicating at 25℃ for 30 min until the solution is clear.

[0017] Further, the mass of the catalyst carrier to the volume of the organic solvent is 1:0.5-10, the unit of mass is g, and the unit of volume is mL; wherein the catalyst carrier is one of tetraethyl orthosilicate, tetrabutyl titanate and g-C3N4; and the organic solvent is one of tetraethylammonium hydroxide, pentanedione and N,N-dimethylformamide.

[0018] Further, the mass ratio of the metal catalytic center reagent to the heteropoly acid and deionized water in step 2) is 1:1-5:20-80.

[0019] Further, the metal catalytic center reagent is one or more of metal compounds of magnesium, cesium, aluminum, titanium, chromium, copper, manganese, iron, cobalt, nickel, cerium, zinc, niobium, cadmium, lead, vanadium, nickel, bismuth and zirconium; and the heteropoly acid is one or more of phosphotungstic acid, silicotungstic acid, phosphomolybdic acid, silicomolybdic acid, silicotungstic acid and silicotungstic acid salt.

[0020] Further, the reaction temperature in step 2) is 80-130℃, and the reaction time is 1-5h; and in step 3), the solid sample is placed into a tube furnace or a microwave reactor for calcination, the calcination temperature is 100-700℃, and the calcination time is 0.5-72h.

[0021] Further, in step 3), the mass of the heterogeneous composite heteropolyacid catalyst precursor to the volume of the catalyst carrier solution and the volume of solvent one is 1:20-70:1-70, the unit of mass is g, and the unit of volume is mL; and the solvent one is one or more of water, methanol, N,N-dimethylformamide, ethanol, acetone, 4-methyl-2-pentanone, acetonitrile, dichloromethane, melamine, ethylene glycol, triethylamine, trichloromethane, carbon tetrachloride, 1,2-dichloroethane, dimethyl sulfoxide, ethylene glycol dimethyl ether, diethyl ether, methyl tert-butyl ether, ethyl acetate, pyridine, benzene, isopropyl alcohol, tetrahydrofuran, 2-methyltetrahydrofuran, polyvinylpyrrolidone and styrene.

[0022] The application further provides a method for preparing 4-hydroxymethyl furfural based on the supported heterogeneous composite heteropolyacid catalyst, wherein the supported heterogeneous composite heteropolyacid catalyst is the catalyst prepared by the preparation method.

[0023] Further, the method, the preparation process is as follows:

[0024] First, the glycerol or glycerol derivatives are pretreated with a pretreatment reagent, and the pretreated material is reacted with a supported heterogeneous composite heteropoly acid catalyst in solvent two at 50-180 DEG C for 0.5-8 h, and after the reaction is completed, it is cooled to room temperature, and the reaction material is filtered and centrifuged to obtain the filtrate, which is the 4-hydroxymethyl furfural to be prepared.

[0025] Further, the mass of the glycerol or glycerol derivative and the volume of the solvent is 1:5-20, the mass unit is g, and the volume is mL; the mass ratio of the glycerol or glycerol derivative to the supported heterogeneous composite heteropoly acid catalyst is 1:0.01-0.5; the pretreatment reagent is one or more of concentrated sulfuric acid, formic acid, acetic acid, concentrated hydrochloric acid, phosphoric acid, sodium thiosulfate, and sodium hydroxide; the solvent two is one or more of water, methanol, N,N-dimethylformamide, ethanol, acetone, 4-methyl-2-pentanone, acetonitrile, dichloromethane, melamine, ethylene glycol, triethylamine, trichloromethane, carbon tetrachloride, 1,2-dichloroethane, dimethyl sulfoxide, ethylene glycol dimethyl ether, diethyl ether, methyl tert-butyl ether, ethyl acetate, pyridine, benzene, isopropyl alcohol, tetrahydrofuran, 2-methyltetrahydrofuran, polyvinylpyrrolidone, and styrene.

[0026] Compared with the prior art, the beneficial effects of the present application are as follows:

[0027] 1) The present application complexes the metal catalytic center reagent and the heteropoly acid in solvent one to obtain a supported heterogeneous composite heteropoly acid catalyst, which can directly convert glycerol or glycerol derivatives into 4-HMF, and the reaction conditions are easy to achieve and the reaction system is simple;

[0028] 2) Compared with traditional homogeneous catalysts, the supported heterogeneous composite heteropoly acid catalyst is easier to separate and recover, and compared with biological catalysis, the supported heterogeneous composite heteropoly acid catalyst maintains high reaction selectivity while requiring lower and milder reaction conditions;

[0029] 3) The supported heterogeneous composite heteropoly acid catalyst of the present application uses non-noble metals as the catalytic center, further reducing the cost;

[0030] 4) The catalyst prepared by the present application has basically unchanged catalytic effect after multiple cycles, perfectly fitting the principles of reduction, recycling, and reuse advocated in the circular economy, and providing a new synthesis method for producing the high-value-added biomass derivative 4-HMF. DETAILED DESCRIPTION

[0031] The application will be further described in conjunction with specific examples, but the scope of the application is not limited to the scope described.

[0032] The content of glycerol or glycerol derivatives (hereinafter referred to as substrate) in the application is detected by Agilent 1260 II liquid chromatograph, and quantified by external standard method.

[0033] The calculation formulae of substrate conversion rate (C), selectivity (S) and 4-HMF (Y) yield are as follows:

[0034]

[0035] Example 1

[0036] The preparation method of the Cs-doped supported heteropoly acid composite catalyst is carried out according to the following steps:

[0037] Step 1: 5.0 g of tetraethyl orthosilicate is weighed into a beaker containing 5.0 g of tetraethylammonium hydroxide, and ultrasonic treatment is carried out at 25℃ for 30 min until it is clear, which is recorded as solution 1;

[0038] Step 2: 0.10 g of Cs2CO3, 0.10 g of H3PW 12 O 40 0.10 g and 50 mL of deionized water are placed into a three-necked flask, and after stirring at 100℃ for 8 h, the mixture is cooled to room temperature, washed with deionized water, centrifuged and separated to obtain a solid, which is recorded as solid 1;

[0039] Step 3: MeOH 10 mL and solid 1 are added to solution 1, and after stirring, ultrasonic treatment is carried out at 80℃ for 30 min to obtain a precursor gel, which is then placed into a tube furnace and calcined at 650℃ under nitrogen atmosphere for 6 h. After cooling to room temperature, the remaining solid is washed with 0.1 wt% H3PO4, and dried at 80℃ under nitrogen atmosphere for 16 h to obtain the required catalyst, which is recorded as 1-Cs@HPA-SiO2.

[0040] Example 2

[0041] The preparation method of the Ce / Zn-doped supported heteropoly acid composite catalyst is carried out according to the following steps:

[0042] Step 1: 5.0 g of tetraethyl orthosilicate is weighed into a beaker containing 5.0 g of tetraethylammonium hydroxide, and ultrasonic treatment is carried out at 25℃ for 30 min until it is clear, which is recorded as solution 1;

[0043] Step 2: 0.65 g of CeO2, 0.80 g of ZnCl2 and 0.10 g of H3PW 12 O 400.10 g of H3PO4, 0.20 g of H3PO4 and 50 mL of deionized water were placed in a three-necked flask, stirred at 100 °C for 8 h, cooled to room temperature, washed with deionized water, centrifuged, and the solid was separated and recorded as solid 1;

[0044] Step 3: solid 1 was added to solution 1, stirred uniformly, and ultrasonicated at 80 °C for 30 min to obtain a precursor gel, which was placed in a tube furnace and calcined at 650 °C under a nitrogen atmosphere for 4 h. After cooling to room temperature, the remaining solid was removed, washed with 0.1 wt% H3PO4, and dried at 80 °C under a nitrogen atmosphere for 16 h to obtain the desired catalyst, which was recorded as 2-Ce / Zn@HPA-SiO2.

[0045] Example 3

[0046] The preparation method of the Pd-doped supported heteropoly acid composite catalyst was carried out according to the following steps:

[0047] Step 1: 5.0 g of tetrabutyl titanate was added to a beaker containing 3.0 g of 2,4-pentanedione, and ultrasonicated at 25 °C for 30 min until clear, which was recorded as solution 1;

[0048] Step 2: 0.20 g of Pb(Ac)2, 0.20 g of H3PMo 12 O 40 0.50 g of H3PO4, 0.15 g of H3PO4 and 50 mL of deionized water were placed in a three-necked flask, stirred at 80 °C for 12 h, cooled to room temperature, centrifuged, and the solid was separated and recorded as solid 1;

[0049] Step 3: solid 1 was added to solution 1, stirred uniformly, and ultrasonicated at 80 °C for 30 min to obtain a precursor gel, which was placed in a tube furnace and calcined at 450 °C under a nitrogen atmosphere for 7 h. After cooling to room temperature, the remaining solid was removed, washed with 0.1 wt% dilute phosphoric acid, and dried at 80 °C under a nitrogen atmosphere for 16 h to obtain the desired catalyst, which was recorded as 3-Pd@HPA-TiO2.

[0050] Example 4

[0051] The preparation method of the Cu-doped supported heteropoly acid composite catalyst was carried out according to the following steps:

[0052] Step 1: 5.0 g of tetrabutyl titanate was added to a beaker containing 3.0 g of 2,4-pentanedione, and ultrasonicated at 25 °C for 30 min until clear, which was recorded as solution 1;

[0053] Step 2: Cu(NO3)2 1.65 g, deionized water 50 mL, NaOH 2.80 g were mixed in a three-neck flask, after stirring at 60 °C for 2 h, the precipitate was taken out, cooled to room temperature, centrifuged, washed with deionized water until neutral, dried at 80 °C under nitrogen for 16 h, and then cooled to obtain the precursor of the heterogeneous composite heteropolyacid catalyst;

[0054] Step 3: H3PW 12 O 40 0.10 g, H3PO4 0.20 g and deionized water 20 mL were placed in a three-neck flask, stirred at 130 °C for 5 h, then cooled to room temperature, centrifuged, and the obtained solid was added to the catalyst carrier solution prepared in step 1), stirred uniformly, and then placed in an oil bath at 100 °C for 1.5 h. After the reaction, the obtained paste was centrifuged and filtered, dried at 80 °C under nitrogen for 5 h, then placed in a tube furnace and calcined at 550 °C under nitrogen atmosphere for 5 h, cooled to room temperature, and then the remaining solid was washed with deionized water and dried at 80 °C under nitrogen for 16 h to obtain the desired catalyst, which was recorded as 4-Cu@HPA-g-C3N4.

[0055] Example 5

[0056] The preparation method of the supported heteropolyacid composite catalyst doped with Al and Ni was carried out according to the following steps:

[0057] Step 1: g-C3N4 5.0 g was added to a beaker containing 30.0 mL of DMF and 14.0 mL of deionized water, and ultrasonic treatment was carried out at 25 °C for 30 min until it became clear, which was recorded as solution 1;

[0058] Step 2: Ni(NO3)2 6.35 g, Al2(NO3)3 1.04 g, deionized water 50 mL, NaOH 6.4 g were mixed in a three-neck flask, after stirring at 60 °C for 2 h, the precipitate was taken out, cooled to room temperature, centrifuged, washed with deionized water until neutral, dried at 80 °C under nitrogen for 16 h, and then cooled to obtain the precursor of the heterogeneous composite heteropolyacid catalyst;

[0059] Step 3: H3PW 12 O 400.10 g, H3PO4 0.20 g and 20 mL of deionized water were placed in a three-necked flask, stirred at 130 °C for 5 h, then cooled to room temperature, centrifuged, and the obtained solid was separated and added to the catalyst carrier solution prepared in step 1). After stirring uniformly, it was placed in an oil bath at 100 °C for 1.5 h. After the reaction, the obtained paste was centrifuged after filtration, dried at 80 °C under nitrogen for 5 h, placed in a tube furnace and calcined at 600 °C under nitrogen atmosphere for 6 h. After cooling to room temperature, the remaining solid was removed and washed with deionized water, and dried at 80 °C under nitrogen for 16 h to obtain the desired catalyst, which was recorded as 5-Al / Ni@HPA-g-C3N4.

[0060] The catalyst prepared in the above example was used to prepare 4-hydroxymethylfurfural.

[0061] Example 6

[0062] The method for preparing 4-HMF from glycerol was carried out as follows:

[0063] Glycerol 4.50 g, catalyst 1-Cs@HPA-SiO2 0.15 g prepared in Example 1 and 50 mL of DMSO were placed in a high-temperature high-pressure reaction kettle, and 2 MPa of oxygen was filled. After stirring at 80 °C for 2 h, the oxygen was emptied, and then the temperature was raised to 130 °C for stirring for 1.5 h. After cooling to room temperature, the total mass in the reaction kettle, the mass of the remaining solid and the mass of the liquid were recorded. The solution was sampled and diluted, and the concentrations of 4-HMF and residual glycerol were determined by HPLC. The yield of 4-HMF in the solution was 28.41%, the conversion rate of glycerol was 62.68%, and the selectivity of glycerol reached 45.33%.

[0064] Example 7

[0065] The method for preparing 4-HMF from glycerol was carried out as follows:

[0066] Glycerol 4.50 g, catalyst 1-Cs@HPA-SiO2 0.15 g prepared in Example 1 and 50 mL of DMSO were placed in a high-temperature high-pressure reaction kettle, and 2 MPa of oxygen was filled. After stirring at 80 °C for 2 h, the oxygen was emptied, and then the temperature was raised to 130 °C for stirring for 1.5 h. After cooling to room temperature, the total mass in the reaction kettle, the mass of the remaining solid and the mass of the liquid were recorded. The solution was sampled and diluted, and the concentrations of 4-HMF and residual glycerol were determined by HPLC. The yield of 4-HMF in the solution was 28.41%, the conversion rate of glycerol was 62.68%, and the selectivity of glycerol reached 45.33%.

[0067] Example 8

[0068] A method for preparing 4-HMF from 1,3-dihydroxyacetone is carried out as follows:

[0069] 1,3-dihydroxyacetone 4.0 g, basic alumina 0.54 g were dissolved in 30 mL of deionized water, stirred at room temperature for 1.5 h, after centrifugal filtration, a small amount of 20% wt acetic acid solution was added to the filtrate, and the filtrate was evaporated under reduced pressure, 40 mL of DMSO, 10 mL of DMAC and the catalyst 3-Pd@HPA-TiO2 obtained in Example 3 were continuously added, the total mass in the reaction kettle, the mass of the remaining solid and the mass of the liquid were recorded after cooling to room temperature, the solution was sampled and diluted, and the concentrations of 4-HMF and the remaining 1,3-dihydroxyacetone were determined by HPLC, the yield of 4-HMF in the solution was calculated to be 39.16%, the conversion rate of 1,3-dihydroxyacetone was 70.33%, and the selectivity of glycerol was 55.68%.

[0070] Example 9

[0071] A method for preparing 4-HMF from glycerol aldehyde is carried out as follows:

[0072] Glycerol aldehyde 3.80 g was dissolved in 30 mL of saturated calcium hydroxide aqueous solution, stirred at room temperature for 1 h, then carbon dioxide was introduced, and the filtrate was obtained after centrifugal filtration, a small amount of 20% wt acetic acid solution was added to the filtrate, and the filtrate was evaporated under reduced pressure, 35 mL of DMSO, 15 mL of DCM and the catalyst 4-Cu@HPA-g-C3N4 0.30 g obtained in Preparation Example 4 were continuously added, and the mixture was stirred at 180°C for 0.5 h in a microwave reactor, the total mass in the reaction kettle, the mass of the remaining solid and the mass of the liquid were recorded after cooling to room temperature, the solution was sampled and diluted, and the concentrations of 4-HMF and the remaining glycerol aldehyde were determined by HPLC, the yield of 4-HMF in the solution was calculated to be 46.75%, the conversion rate of glycerol aldehyde was 69.53%, and the selectivity of glycerol was 67.24%.

[0073] Example 10

[0074] A method for preparing 4-HMF from 1,3-dihydroxyacetone is carried out as follows:

[0075] Glycerol 4.75 g was dissolved in 30 mL saturated calcium hydroxide aqueous solution, stirred at room temperature for 1 h, then carbon dioxide was bubbled in, and the filtrate was obtained by filtration and centrifugation. A small amount of 20% wt acetic acid solution was added to the filtrate, and the filtrate was evaporated under reduced pressure. 20 mL DMSO, 20 mL DMAC and the catalyst 5-Al / Ni@HPA-g-C3N4 obtained in Preparation Example 5 were added, and the mixture was stirred in a high-temperature and high-pressure reaction kettle at 150°C for 2 h. After cooling to room temperature, the total mass in the reaction kettle, the mass of the remaining solid and the mass of the liquid were recorded. The solution was sampled and diluted, and the concentrations of 4-HMF and residual 1,3-dihydroxyacetone were determined by HPLC. The yield of 4-HMF in the solution was calculated to be 43.17%, the conversion rate of 1,3-dihydroxyacetone was 65.39%, and the selectivity of glycerol was 66.02%.

[0076] Recovery of the catalyst

[0077] Example 11

[0078] The catalyst 1-Cs@HPA-SiO2 after the catalytic reaction was recovered, washed with deionized water, acetone and 0.1% wt phosphoric acid alternately for at least 3 times, and then dried at 80°C under a nitrogen atmosphere for 15 h. The regenerated catalyst was placed in a tube furnace and activated at 600°C under a nitrogen atmosphere for 3 h, and was recorded as 1-Cs@HPA-SiO2(R).

[0079] The 1-Cs@HPA-SiO2(R) was used to repeat the experiment of Example 6 for 10 times. The average yield of 4-HMF was calculated to be 26.97%, the conversion rate of glycerol was 61.52%, and the selectivity of glycerol was 43.84%. The catalytic performance of the catalyst remained basically unchanged after multiple cycles.

[0080] Example 12

[0081] The method for preparing 4-HMF from glycerol using the recovered catalyst, was carried out as follows:

[0082] The catalyst 2-Ce / Zn@HPA-SiO2 after the catalytic reaction was recovered, washed with deionized water, acetone and 0.1% wt phosphoric acid alternately for at least 3 times, and then dried at 80°C under a nitrogen atmosphere for 15 h. The regenerated catalyst was placed in a tube furnace and activated at 600°C under a nitrogen atmosphere for 3 h, and was recorded as 2-Ce / Zn@HPA-SiO2(R).

[0083] The 2-Ce / Zn@HPA-SiO2(R) was used to repeat the experiment of Example 7 for 15 times. The average yield of 4-HMF was calculated to be 37.08%, the conversion rate of glycerol was 67.32%, and the selectivity of glycerol was 55.08%. The catalytic performance of the catalyst remained basically unchanged after multiple cycles.

[0084] Example 13

[0085] The method for preparing 4-HMF from 1,3-dihydroxyacetone using the recovered catalyst is carried out according to the following steps:

[0086] The catalyst 3-Pd@HPA-TiO2 after the catalytic reaction is recovered, washed with deionized water, acetone and 0.1%wt phosphoric acid alternately for at least 3 times, then dried at 80°C under nitrogen atmosphere for 15h, activated at 600°C under nitrogen atmosphere in a tube furnace for 3h, and recorded as 3-Pd@HPA-TiO2(R) after regeneration.

[0087] The experiment of Example 8 is repeated 15 times using the 3-Pd@HPA-TiO2(R), and the average yield of 4-HMF is calculated to be 37.93%, the conversion rate of 1,3-dihydroxyacetone is 70.68%, and the selectivity of glycerol is 53.70%. The catalytic performance of the catalyst remains basically unchanged after being used repeatedly for multiple times.

[0088] Example 14

[0089] The method for preparing 4-HMF from glycerol using the recovered catalyst is carried out according to the following steps:

[0090] The catalyst 4-Cu@HPA-g-C3N4 after the catalytic reaction is recovered, washed with deionized water, acetone and 0.1%wt phosphoric acid alternately for at least 3 times, then dried at 80°C under nitrogen atmosphere for 15h, activated at 600°C under nitrogen atmosphere in a tube furnace for 3h, and recorded as 4-Cu@HPA-g-C3N4(R) after regeneration.

[0091] The experiment of Example 9 is repeated 15 times using the 4-Cu@HPA-g-C3N4(R), and the average yield of 4-HMF is calculated to be 44.98%, the conversion rate of glycerol is 69.35%, and the selectivity of glycerol is 64.86%. The catalytic performance of the catalyst remains basically unchanged after being used repeatedly for multiple times.

[0092] Example 15

[0093] The method for preparing 4-HMF from 1,3-dihydroxyacetone using the recovered catalyst is carried out according to the following steps:

[0094] The catalyst 5-Al / Ni@HPA-g-C3N4 after the catalytic reaction is recovered, washed with deionized water, acetone and 0.1%wt phosphoric acid alternately for at least 3 times, then dried at 80°C under nitrogen atmosphere for 15h, activated at 600°C under nitrogen atmosphere in a tube furnace for 3h, and recorded as 5-Al / Ni@HPA-g-C3N4(R) after regeneration.

[0095] The experiment of the 5-Al / Ni@HPA-g-C3N4(R) was repeated for 15 times, and the average yield of 4-HMF was 37.06%, the conversion rate of 1,3-dihydroxyacetone was 71.88%, and the selectivity of glycerol reached 51.56%. The catalytic performance of the catalyst remained basically unchanged after repeated use for several times.

[0096] From the above experimental results, it can be seen that the yield of 4-HMF generated by catalyzing glycerol or glycerol derivatives by the method of the present application can reach 46.75% at most.

[0097] Compared with biological catalysis, the present method has lower requirements for reaction conditions. The by-product glycerol or glycerol derivatives generated by traditional chemical and biological refining are catalyzed to generate 4-HMF, which not only meets the 3R principle in circular economy, but also finds a new breakthrough point for carbon cycle in nature.

[0098] In summary, the reaction conditions of the method are easy to achieve, the supported heterogeneous composite heteropolyacid catalyst uses non-noble metal as the catalytic center, further reduces the cost, and has high energy utilization rate; at the same time, a new synthesis method is provided for producing high-value-added 4-HMF.

Claims

1. A process for the preparation of 4-hydroxymethylfurfural based on a supported heterogeneous composite heteropolyacid catalyst, characterized in that The catalyst is prepared according to the following method: 1) Prepare a catalyst carrier solution for use; 2) Add the metal catalytic center reagent and heteropoly acid into a three-necked flask containing deionized water, and carry out the reaction under the condition of heating and stirring. After the reaction is completed and the reaction mixture is cooled to room temperature, the polyphase composite heteropoly acid catalyst precursor is obtained by filtration and centrifugation; 3) Add the catalyst carrier solution prepared in step 1) and solvent 1 to the polyphase composite heteropoly acid catalyst precursor obtained in step 2), mix uniformly, filter out the mixed solvent, and obtain a solid sample. Then, the solid sample is calcined. After the calcination is completed and the calcined material is cooled to room temperature, the material is washed and dried to obtain the catalyst to be prepared; The specific process of step 1) is as follows: add the catalyst carrier into a beaker containing an organic solvent, and ultrasonicate at 25℃ for 30 min until it is clear. The mass of the catalyst carrier to the volume of the organic solvent is 1:0.5-10, with the unit of mass being g and the unit of volume being mL; wherein the catalyst carrier is one of tetraethyl orthosilicate, tetrabutyl titanate and g-C3N4; and the organic solvent is one of tetraethylammonium hydroxide, pentanedione and N,N-dimethylformamide; The metal catalytic center reagent is one or more of metal compounds of magnesium, cesium, aluminum, titanium, chromium, copper, manganese, iron, cobalt, cerium, zinc, niobium, cadmium, lead, vanadium, nickel, bismuth and zirconium; and the heteropoly acid is one or more of phosphotungstic acid, silicotungstic acid, phosphomolybdic acid and silicomolybdic acid.

2. A process for the preparation of 4-hydroxymethylfurfural based on a supported heterogeneous composite heteropolyacid catalyst according to claim 1, characterized in that The mass ratio of the metal catalytic center reagent to the heteropoly acid and deionized water in step 2) is 1:1-5:20-80.

3. A process for the preparation of 4-hydroxymethylfurfural based on a supported heterogeneous composite heteropolyacid catalyst according to claim 1, characterized in that The reaction temperature in step 2) is 80-130℃, and the reaction time is 1-5h; and in step 3), the solid sample is placed into a tube furnace or a microwave reactor for calcination, with the calcination temperature being 100-700℃ and the calcination time being 0.5-72h.

4. The process for the preparation of 4-hydroxymethylfurfural based on supported heterogeneous composite heteropolyacid catalyst according to claim 1, characterized in that In step 3), the mass of the polyphase composite heteropoly acid catalyst precursor to the volume of the catalyst carrier solution and the volume of solvent 1 is 1:20-70:1-70, with the unit of mass being g and the unit of volume being mL; and solvent 1 is one or more of water, methanol, N,N-dimethylformamide, ethanol, acetone, 4-methyl-2-pentanone, acetonitrile, dichloromethane, ethylene glycol, triethylamine, trichloromethane, carbon tetrachloride, 1,2-dichloroethane, dimethyl sulfoxide, ethylene glycol dimethyl ether, diethyl ether, methyl tert-butyl ether, ethyl acetate, pyridine, benzene, isopropyl alcohol, tetrahydrofuran, 2-methyltetrahydrofuran, polyvinylpyrrolidone and styrene.

5. A process for the preparation of 4-hydroxymethylfurfural based on a supported heterogeneous composite heteropolyacid catalyst according to claim 1, characterized in that The specific preparation process is as follows: First, the glycerol or glycerol derivative is pretreated with a pretreatment reagent, and the pretreated material is reacted with the supported polyphase composite heteropoly acid catalyst in solvent 2 at 50-180℃ for 0.5-8h. After the reaction is completed and the reaction mixture is cooled to room temperature, the filtrate obtained by filtration and centrifugation is the 4-hydroxymethylfurfural to be prepared.

6. The process for the preparation of 4-hydroxymethylfurfural based on supported heterogeneous composite complex acid catalyst according to claim 5, characterized in that The mass of the glycerol or glycerol derivative to the volume of the solvent is 1:5-20, the mass unit is g, and the volume is mL; the mass ratio of the glycerol or glycerol derivative to the supported heterogeneous composite heteropoly acid catalyst is 1:0.01-0.5; the pretreatment reagent is one or more of concentrated sulfuric acid, formic acid, acetic acid, concentrated hydrochloric acid, phosphoric acid, sodium thiosulfate, and sodium hydroxide; and the solvent is one or more of water, methanol, N,N-dimethylformamide, ethanol, acetone, 4-methyl-2-pentanone, acetonitrile, dichloromethane, ethylene glycol, triethylamine, chloroform, carbon tetrachloride, 1,2-dichloroethane, dimethyl sulfoxide, ethylene glycol dimethyl ether, diethyl ether, methyl tert-butyl ether, ethyl acetate, pyridine, benzene, isopropyl alcohol, tetrahydrofuran, 2-methyltetrahydrofuran, polyvinylpyrrolidone, and styrene.

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