A method for catalyzing dehydration of glucose to 5-hydroxymethylfurfural by a multi-level pore bifunctional solid acid catalyst

Abstract

The present application belongs to the field of solid acid catalyst synthesis, and particularly relates to a method for catalyzing glucose dehydration to generate 5-hydroxymethylfurfural by using a multi-stage hole bifunctional solid acid catalyst. The method is as follows: a sol-gel phase separation method is used to synthesize a multi-stage hole structure (large hole and mesopore) phosphotantalum oxide solid acid with a highly uniform pore size distribution. The catalyst has high surface stability, a large crystal defect site density, and can efficiently and continuously catalyze glucose isomerization to fructose and fructose dehydration to generate 5-hydroxymethylfurfural in an aqueous phase. The method realizes the conversion of catalytic glucose dehydration to the biomass platform compound molecule 5-hydroxymethylfurfural under green conditions, and the catalyst is stable.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of catalytic reaction of biomass aldehyde sugar to prepare 5-hydroxymethylfurfural, and particularly relates to a method for synthesizing 5-hydroxymethylfurfural with high selectivity. The present application belongs to the field of catalytic conversion of biomass, and particularly relates to a method for synthesizing a multi-stage hole dual-function solid acid catalyst for catalyzing glucose dehydration to generate 5-hydroxymethylfurfural. BACKGROUND

[0002] The shortage of fossil resources such as petroleum and coal and the trade barriers caused by carbon tax have affected the economic development and the guarantee of people's living standards in China. Cellulose is a rich and inexpensive resource in nature, which can be used as a carbon source and energy source, and can be converted into numerous chemicals and high value-added products through catalysis. At present, the main catalytic conversion path is to hydrolyze cellulose into glucose, isomerize glucose into fructose, and then dehydrate fructose to generate 5-hydroxymethylfurfural (HMF). 5-hydroxymethylfurfural can be catalytically converted into various chemicals through processes such as oxidation and hydrogenation, such as furan dimethyl acid generated after oxidation, and long-chain polyols generated after hydrogenation reduction. Therefore, HMF is called "platform compound", and the efficient preparation of HMF restricts the utilization efficiency of cellulose biomass and the ultimate economy. At present, the design of catalyst has been listed as a key bottleneck problem in the academic and industrial circles.

[0003] However, the current HMF production is mainly based on crystalline fructose as raw material, and the price of fructose is high, and the international market fluctuation is large, which leads to the high price of HMF and its downstream conversion products, and the lack of economy and practicability. Many studies focus on the preparation of HMF from glucose as raw material. The key and difficulty of this reaction path is to develop a bifunctional catalyst with matching reaction kinetics, that is, glucose needs to undergo two-step reaction to convert into HMF, glucose is first isomerized into fructose, and then fructose is dehydrated to generate HMF; the catalyst surface requires the presence of Lewis acid catalytic sites for catalyzing the conversion of glucose into fructose and proton acid sites for catalyzing the dehydration of fructose to generate HMF, and the two types of catalytic sites need to be consistent in apparent reaction kinetics. However, the process of glucose conversion into HMF is accompanied by many side reactions such as thermal decomposition, which is a complex reaction path coexisting with continuous reaction and parallel reaction, and the side reactions have strong competitiveness in thermodynamics and kinetics. In order to realize the efficient conversion of glucose into HMF, the Lewis acid sites and proton acid sites of the catalyst need to have high kinetics performance for the main reaction and strong stability in aqueous reaction. However, the reported niobium-zirconium-based catalysts still have some deficiencies in catalytic activity, stability and reaction kinetics performance under high substrate concentration conditions. Compared with niobium and zirconium, the enthalpy of formation of tantalum oxide or phosphate is larger, and it has high stability in water. CN102477020A a method for catalyzing carbohydrates to prepare 5-hydroxymethylfurfural, the phosphated tantalum oxide or the phosphotantalum prepared by the tartaric acid-phosphoric acid precipitation method has Lewis acid sites and proton acid sites at the same time, and can catalyze the conversion of glucose into HMF; the yield of HMF can reach 78% in a two-phase system. However, the surface structure of the catalyst is unstable during the reaction, and the active site ions such as phosphate are easy to flow into the reaction liquid, the distribution of the catalytic sites on the surface of the catalyst is uneven, physical and chemical carbon deposition is easy to occur, which leads to the decrease of the reusability of the catalyst; the catalyst can catalyze the degradation of HMF in aqueous solution, which reduces the yield and selectivity of HMF; and the catalyst is easy to deactivate under high substrate concentration conditions, and the overall reaction efficiency is very low.

[0004] Therefore, it is urgent to develop a tantalum-based bifunctional catalyst with high stability and high kinetics performance in the reaction process in aqueous solution, which can catalyze the conversion of glucose and other aldehyde-type six-carbon sugars into HMF. SUMMARY

[0005] The purpose of the present application is to provide a method for catalytically preparing HMF from glucose, in order to overcome the defects of the current technology. The method of the present application is to synthesize a bifunctional phosphotantalum oxide solid acid catalyst with uniform pore size distribution and large specific surface area by non-equilibrium sol-gel phase separation method, combined with organic acid coordination to control the sol-gel reaction rate between ethoxy tantalum and phosphoric acid and provide a template for mesopore formation.

[0006] The synthesized catalyst is high in crystallinity and large in defect structure density of crystal ion vacancies after calcination activation, thereby improving the physical adsorption and chemical adsorption activation of the catalyst to substrate molecules, and having uniformly distributed and high stability Lewis acid sites and proton acid sites. The catalyst can continuously and efficiently catalyze the ketonization and dehydration reaction of glucose in an aqueous phase to generate HMF, and the generated HMF can be further extracted and separated in a water-organic solvent two-phase reaction system, thereby improving the generation rate and selectivity of HMF. The catalyst still has micron-sized large pores after calcination activation, and the diffusion limitation of reactants and products is small, which can improve the apparent reaction kinetics of reactant conversion and reduce the further conversion of products to humus. The surface structure is stable after recycling at high temperature for multiple times, and the catalyst still has high reaction activity. Therefore, the bifunctional solid acid catalyst for converting glucose to HMF is prepared by a simple process, and has high stability and strong reaction kinetics, and HMF with high content can be obtained under high substrate concentration.

[0007] In order to achieve the purpose of the present application, the specific technical scheme adopted is:

[0008] The multi-level pore phosphotungstic acid bifunctional solid acid catalyst for preparing 5-hydroxymethylfurfural from glucose and a preparation method thereof comprise the following steps: dispersing and dissolving the multi-level pore phosphotungstic acid solid acid catalyst and glucose in an aqueous solution, adding a low-boiling organic solvent to extract the generated HMF to prevent the condensation and thermal decomposition of HMF and the substrate glucose, reacting at 140 DEG C to 190 DEG C for 10 to 600 minutes, centrifugally separating the phosphotungstic acid bifunctional solid acid catalyst, and then separating and purifying to obtain HMF.

[0009] Further, the low-boiling organic solvent is selected from the group consisting of methyl isobutyl ketone, n-butanol, tetrahydrofuran, ethyl acetate, dimethyl sulfoxide, ethanol and mixtures thereof. Methyl isobutyl ketone is preferred.

[0010] Further, the volume ratio of water to low-boiling organic solvent is 1:1 to 1:5. We have found through experimental parameter optimization that the preparation efficiency of HMF is the highest when the ratio of water to methyl isobutyl ketone is 3:7.

[0011] Further, the mass concentration of glucose in water is 1% to 20%. The mass ratio of the multi-level pore phosphotungstic acid solid acid catalyst to glucose is 1:5 to 1:40.

[0012] Further, as preferred, the reaction is carried out at 170 DEG C to 180 DEG C, and the yield of HMF is higher.

[0013] The bifunctional solid acid catalyst of tantalum oxyphosphate is obtained by the following method: dissolving tantalum chloride in alcohol and reacting at 60-90°C for 2-6 hours to form tantalum alkoxide, cooling to room temperature, adding organic acid, polyethylene glycol and water and stirring until dissolved, and finally adding concentrated phosphoric acid and gelling, removing the organic acid and solvent in the gel by solvent exchange and vacuum drying to obtain a dry gel material of tantalum oxyphosphate, which is activated by calcination at 500-1100°C to obtain the bifunctional solid acid catalyst of tantalum oxyphosphate.

[0014] Further, the alcohol can be methanol, ethanol, n-propanol or isopropanol; preferably, ethanol has the best effect.

[0015] Further, the organic acid can be citric acid, lactic acid, malic acid, hexanoic acid, tartaric acid or a mixture of the above organic acids, and citric acid has the best effect as a pore-forming agent; citric acid is added to generate mesopores by calcination because citric acid can coordinate with Ta 5+ and can be distributed in the framework of the TaP material. After adding citric acid, the porosity parameters of the TaP material are significantly improved and the specific surface area is increased.

[0016] Further, in order to ensure that the prepared bifunctional solid acid of tantalum oxyphosphate generates co-continuous macropores and mesopores with uniform pore size distribution, the present application further limits the high polymer to be polyethylene glycol according to specific reaction conditions. The amount of polyethylene glycol is 10-30 g / mol-tantalum chloride. The molar ratio of organic acid to tantalum chloride is 0.25:1-2:1, and the molar ratio of concentrated phosphoric acid to tantalum chloride is 1:1-4:1.

[0017] Preferably, when the molar ratio of organic acid to tantalum chloride is 1:1 and the molar ratio of concentrated phosphoric acid to tantalum chloride is 2:1, the specific surface area of the obtained tantalum oxyphosphate dry gel is higher after calcination at 600°C for 8 hours, and the catalytic effect is also the best. The material synthesized when the volume ratio of ethanol to water is 5:3 exhibits uniform macropore distribution.

[0018] The high-crystallinity hierarchical porous tantalum oxyphosphate is prepared by the sol-gel phase separation method combined with organic acid coordination to control the reaction rate, a bifunctional solid acid with Lewis acid sites for catalyzing aldose ketonization reaction and proton acid sites for catalyzing ketose dehydration is constructed, and HMF is generated by catalyzing glucose consecutive reaction. Thus, HMF is efficiently prepared by a two-phase one-pot method under relatively mild conditions by a simple process.

[0019] The application further provides a preparation method of the high-efficiency bifunctional solid acid catalyst of tantalum oxyphosphate for catalyzing glucose to prepare HMF in a water / organic solvent two-phase system, comprising the following steps: through a solution homogeneous reaction, the precursor is in an atomic level mixed state, the reaction rate of the sol-gel process is controlled by using organic acid coordination, an organic polymer is added as a phase separation inducer, water is added to hydrolyze the tantalum alkoxide into hydrated tantalum hydroxide, and finally, concentrated phosphoric acid is added to obtain a tantalum oxyphosphate gel material, the material is dried and calcined, and the bifunctional solid acid catalyst of tantalum oxyphosphate is obtained. According to the gelation polymerization reaction and phase separation control conditions, 1M hydrochloric acid or water / ice bath can be added.

[0020] Compared with the prior art, the application has the following beneficial effects:

[0021] 1. The bifunctional solid acid catalyst of tantalum oxyphosphate has the performance of catalyzing high-concentration biomass-based aldose to generate platform compound 5-hydroxymethylfurfural (HMF) in a one-pot method in a water-organic solvent two-phase system, realizes green and efficient catalysis of sugar biomass conversion, and the bifunctional solid acid catalyst of tantalum oxyphosphate is a solid-liquid catalytic system, has small corrosion to equipment, and has higher operability in the production process after the catalyst is separated out through filtration or centrifugation after the reaction is completed.

[0022] 2. The bifunctional solid acid catalyst has high crystallinity, less ion leakage in the water phase reaction process, high water phase stability of Lewis acid sites, high reaction kinetics performance, stable structure after calcination recovery, and can be repeatedly used for many times, and can efficiently catalyze aldose to ketose conversion.

[0023] 3. The bifunctional solid acid catalyst has weakly acidic and moderately strong acidic proton acidity, can selectively catalyze ketose dehydration and glycosidic bond hydrolysis, and thus can prepare HMF by using polysaccharides as raw materials through cascade catalysis. Meanwhile, because the proton acidity is not strong, the generated HMF is not easy to be further catalytically decomposed into formic acid and acetylpropionic acid, and thus the yield of the product HMF is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The scanning electron microscope image of the TaP-600 bifunctional tantalum oxyphosphate prepared in Example 5 of the application.

[0025] Figure 2 The N2 adsorption-desorption isotherm of the bifunctional solid acid catalyst of tantalum oxyphosphate under different calcination temperatures.

[0026] Figure 3 Figure 8 shows the effect of heat treatment on the sample of the phosphotungstic acid bifunctional solid acid catalyst; (a) is a Fourier transform infrared (FT-IR) absorption spectrum of the phosphotungstic acid bifunctional solid acid catalyst TaP-600; (b) is an X-ray diffraction pattern of the phosphotungstic acid bifunctional solid acid catalyst at 300-900°C. DETAILED DESCRIPTION

[0027] The present application is not limited to the following detailed description, and those skilled in the art can implement the present application in other various embodiments according to the disclosure of the present application, or any simple changes or modifications made by using the design structure and ideas of the present application, and all fall within the protection scope of the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0028] The method for preparing 5-hydroxymethylfurfural from glucose in the water-organic solvent two-phase system of the present application comprises controlling the bifunctional solid acid catalyst to be fully dispersed in the aqueous glucose solution, the mass ratio of the bifunctional solid acid catalyst to glucose being 1:5-1:40, reacting at 140-190°C for 10-600 minutes, centrifugally separating the bifunctional solid acid catalyst, and then separating and purifying to obtain 5-hydroxymethylfurfural; the bifunctional solid acid catalyst is a phosphotungstic acid solid acid catalyst with mesoporous and macroporous structures, the catalyst has high crystallinity, less metal ion leakage in the aqueous phase reaction, and high surface stability. The method of the present application can realize high-efficiency preparation of 5-hydroxymethylfurfural, and has obvious technical advantages compared with the prior art. Meanwhile, the catalyst provided by the present application can also catalyze dehydration of galactose, mannose and other six-carbon sugars to obtain HMF, and catalyze dehydration of xylose, arabinose and other five-carbon sugars to obtain furfural.

[0029] Example 1: Phosphotungstic acid xerogel with co-continuous macroporous structure

[0030] Dissolve 1 mol of tantalum chloride in 500 ml of ethanol, fully react at 80°C for 4 hours, cool to room temperature, add 300 ml of ultrapure water and 22.5 grams of polyethylene glycol with a molecular weight of 35,000, fully stir to uniform, then add 140 ml of concentrated phosphoric acid, exchange the obtained white solid with water, methanol and n-hexane solvents, and vacuum dry to obtain a phosphotungstic acid xerogel with co-continuous macroporous structure. The specific surface area of the xerogel after calcination at 600°C for 8 hours is 6.0 m 2 / g, and the pore volume is 0.014 cm 3 / g.

[0031] Example 2: Phosphotungstic acid xerogel with co-continuous macroporous structure

[0032] 1 mol of tantalum chloride was dissolved in 500 ml of ethanol and reacted at 80 °C for 4 hours. After cooling to room temperature, 300 ml of ultrapure water, 50 g of citric acid, and 22.5 g of polyethylene glycol with a molecular weight of 35,000 were added. After thorough stirring, 140 ml of concentrated phosphoric acid was added. The resulting white solid was exchanged with water, methanol, and n-hexane, and then dried under vacuum to obtain a tantalum oxyphosphate dry gel with a co-continuous macroporous structure. The specific surface area of ​​this dry gel was 146 m² after calcination at 600 °C for 8 hours. 2 / g, pore volume 0.041cm 3 / g.

[0033] Example 3: Tantalum oxyphosphate dry gel with a co-continuous macroporous structure

[0034] 1 mol of tantalum chloride was dissolved in 500 ml of ethanol and reacted at 80 °C for 4 hours. After cooling to room temperature, 300 ml of ultrapure water, 100 g of citric acid, and 22.5 g of polyethylene glycol with a molecular weight of 35,000 were added. After thorough stirring, 140 ml of concentrated phosphoric acid was added. The resulting white solid was exchanged with water, methanol, and n-hexane, and then dried under vacuum to obtain a tantalum oxyphosphate dry gel with a co-continuous macroporous structure. The specific surface area of ​​this dry gel was 138 m² after calcination at 600 °C for 8 hours. 2 / g, pore volume 0.12cm 3 / g.

[0035] Example 4: Tantalum oxyphosphate dry gel with a co-continuous macroporous structure

[0036] 1 mol of tantalum chloride was dissolved in 500 ml of ethanol and reacted at 80°C for 4 hours. After cooling to room temperature, 300 ml of ultrapure water, 200 g of citric acid, and 22.5 g of polyethylene glycol with a molecular weight of 35,000 were added. After thorough mixing, 140 ml of concentrated phosphoric acid was added. The resulting white solid was exchanged with water, methanol, and n-hexane, and then dried under vacuum to obtain a tantalum oxyphosphate dry gel with a co-continuous macroporous structure. The specific surface area of ​​this dry gel was 8.9 m² after calcination at 600°C for 8 hours. 2 / g, pore volume 0.045cm 3 / g.

[0037] Example 5: Preparation of Tantalum oxyphosphate dry gel with co-continuous macroporous structure and bifunctional catalyst

[0038] The 1 mol of tantalum chloride was dissolved in 500 ml of ethanol, and reacted at 80°C for 4 hours. After cooling to room temperature, 300 ml of ultrapure water, 150 g of citric acid and 22.5 g of polyethylene glycol with a molecular weight of 35,000 were added. After stirring, 140 ml of concentrated phosphoric acid was added. The obtained white solid was exchanged with water, methanol and n-hexane, and dried in vacuum to obtain a phosphotantalite xerogel with a co-continuous macroporous structure. The phosphotantalite xerogel was calcined at 500-1000°C for 8 hours in a high-temperature furnace to obtain a phosphotantalite bifunctional catalyst, which was denoted as TaP-X, wherein X was the calcination temperature.

[0039] The phosphotantalite bifunctional catalyst TaP-600 was obtained by calcination at 600°C for 8 hours. The specific surface area was 103 m 2 / g, the pore volume was 0.089 cm 3 / g, and the pore size was 3.48 nm.

[0040] The phosphotantalite bifunctional catalyst TaP-700 was obtained by calcination at 700°C for 8 hours. The specific surface area was 30 m 2 / g.

[0041] The phosphotantalite bifunctional catalyst TaP-900 was obtained by calcination at 900°C for 8 hours. The specific surface area was 4 m 2 / g.

[0042] The phosphotantalite bifunctional catalyst TaP-550 was obtained by calcination at 550°C for 8 hours. The specific surface area was 60 m 2 / g.

[0043] Figure 2 The N2 adsorption-desorption isotherms of the phosphotantalite bifunctional solid acid catalysts calcined at different temperatures are shown in Figure 1. The isotherms of the TaP samples calcined at 550°C and 600°C were typical type IV isotherms, and the hysteresis loop was between 0.4 and 1.0 (p / p0), which indicated the inherent characteristics of the mesoporous material. The N2 adsorption between 0.1 and 0.4 (p / p 0 ) was attributed to the existence of micropores. The S BET , V P and D P values of the TaP sample calcined at 600°C were the highest, which were 103 m 2 / g, 0.089 cm 3 / g and 3.48 nm, respectively.

[0044] Example 6: Phosphotantalite xerogel with a co-continuous macroporous structure

[0045] 1 mol of tantalum chloride was dissolved in 500 ml of methanol and reacted at 80 °C for 4 hours. After cooling to room temperature, 300 ml of ultrapure water, 150 g of citric acid, and 22.5 g of polyethylene glycol with a molecular weight of 35,000 were added. After thorough stirring, 140 ml of concentrated phosphoric acid was added. The resulting white solid was subjected to solvent exchange with water, methanol, and n-hexane, and then vacuum dried to obtain a porous tantalum oxyphosphate dry gel. The specific surface area of ​​this dry gel was 1.9 m² / g after calcination at 600 °C for 8 hours. 2 / g.

[0046] Example 7: Tantalum oxyphosphate dry gel with a co-continuous macroporous structure

[0047] 1 mol of tantalum chloride was dissolved in 500 ml of n-propanol and reacted at 80°C for 4 hours. After cooling to room temperature, 300 ml of ultrapure water, 150 g of citric acid, and 22.5 g of polyethylene glycol with a molecular weight of 35,000 were added. After thorough stirring, 140 ml of concentrated phosphoric acid was added. The resulting white solid was subjected to solvent exchange with water, methanol, and n-hexane, and then vacuum dried to obtain a porous tantalum oxyphosphate dry gel. The specific surface area of ​​this dry gel was 3.5 m² after calcination at 600°C for 8 hours. 2 / g.

[0048] Example 8: Tantalum oxyphosphate dry gel with a co-continuous macroporous structure

[0049] 1 mol of tantalum chloride was dissolved in 500 ml of isopropanol and reacted at 80 °C for 4 hours. After cooling to room temperature, 300 ml of ultrapure water, 150 g of citric acid, and 22.5 g of polyethylene glycol with a molecular weight of 35,000 were added. After thorough stirring, 140 ml of concentrated phosphoric acid was added. The resulting white solid was exchanged with water, methanol, and n-hexane, and then dried under vacuum to obtain a porous tantalum oxyphosphate dry gel. The specific surface area of ​​this dry gel was 4.3 m² after calcination at 600 °C for 8 hours. 2 / g.

[0050] Example 9: Tantalum oxyphosphate dry gel with a co-continuous macroporous structure

[0051] 1 mol of tantalum chloride was dissolved in 500 ml of ethanol and reacted at 80 °C for 4 hours. After cooling to room temperature, 300 ml of ultrapure water, 90 g of lactic acid, and 22.5 g of polyethylene glycol with a molecular weight of 35,000 were added. After thorough mixing, 140 ml of concentrated phosphoric acid was added. The resulting white solid was exchanged with water, methanol, and n-hexane, and then dried under vacuum to obtain a tantalum oxyphosphate dry gel with a co-continuous macroporous structure. The specific surface area of ​​this dry gel was 2 m² after calcination at 600 °C for 8 hours. 2 / g.

[0052] Example 10: Tantalum oxyphosphate dry gel with a co-continuous macroporous structure

[0053] Example 1 Preparation of the phosphotungstic acid xerogel with co-continuous macroporous structure 2 / g.

[0054] Example 11 Preparation of the phosphotungstic acid xerogel with co-continuous macroporous structure

[0055] Dissolve 1 mol of the chloroplatinic acid in 500 ml of ethanol, and react at 80°C for 4 hours. After cooling to room temperature, add 300 ml of ultrapure water, 50 g of tartaric acid, and 22.5 g of polyethylene glycol with a molecular weight of 35,000. After stirring well, add 140 ml of concentrated phosphoric acid. The white solid obtained is exchanged with water, methanol, and n-hexane solvents, and dried in vacuum to obtain the phosphotungstic acid xerogel with co-continuous macroporous structure. The specific surface area of the xerogel after calcination at 600°C for 8 hours is 2 m 2 / g.

[0056] Example 12 Preparation of the phosphotungstic acid xerogel with co-continuous macroporous structure

[0057] Dissolve 1 mol of the chloroplatinic acid in 500 ml of ethanol, and react at 80°C for 4 hours. After cooling to room temperature, add 300 ml of ultrapure water, 134 g of malic acid, and 22.5 g of polyethylene glycol with a molecular weight of 35,000. After stirring well, add 140 ml of concentrated phosphoric acid. The white solid obtained is exchanged with water, methanol, and n-hexane solvents, and dried in vacuum to obtain the phosphotungstic acid xerogel with co-continuous macroporous structure. The specific surface area of the xerogel after calcination at 600°C for 8 hours is 21 m 2 / g.

[0058] The preparation methods of the phosphotungstic acid solid acids TaP-600, TaP-700, and TaP-900 described in the following examples are the same as those in Example 5.

[0059] Example 13 Preparation of HMF from glucose by using the phosphotungstic acid TaP-600 solid acid catalyst

[0060] Dissolve 1 g of glucose in 100 ml of deionized water, and add 0.1 g of the phosphotungstic acid solid acid TaP-600. Stir at 170°C for 4 hours, and then cool to room temperature. The reaction solution is centrifuged at 10,000 r / min to remove the solid catalyst. The HMF molar yield is 25.8% by high performance liquid chromatography analysis.

[0061] Example 14 Tantalum Phosphate TaP-700 solid acid catalyze glucose to prepare HMF

[0062] Dissolve 1 g glucose in 100 ml deionized water, add 0.1 g tantalum phosphate solid acid TaP-700, stir at 170°C for 4 hours, then cool to room temperature. The reaction liquid is centrifuged at 10000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography, the molar yield of HMF is 23.6%.

[0063] Example 15 Tantalum Phosphate TaP-900 solid acid catalyze glucose to prepare HMF

[0064] Dissolve 1 g glucose in 100 ml deionized water, add 0.1 g tantalum phosphate solid acid TaP-900, stir at 170°C for 4 hours, then cool to room temperature. The reaction liquid is centrifuged at 10000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography, the molar yield of HMF is 16.4%.

[0065] Example 16 Tantalum Phosphate TaP-600 solid acid catalyze glucose to prepare HMF

[0066] Dissolve 1 g glucose in 100 ml deionized water, add 0.1 g tantalum phosphate solid acid TaP-600, stir at 140°C for 6 hours, then cool to room temperature. The reaction liquid is centrifuged at 10000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography, the molar yield of HMF is 7.5%.

[0067] Example 17 Tantalum Phosphate TaP-600 solid acid catalyze glucose to prepare HMF

[0068] Dissolve 1 g glucose in 100 ml deionized water, add 0.1 g tantalum phosphate solid acid TaP-600, stir at 150°C for 6 hours, then cool to room temperature. The reaction liquid is centrifuged at 10000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography, the molar yield of HMF is 12.8%.

[0069] Example 18 Tantalum Phosphate TaP-600 solid acid catalyze glucose to prepare HMF

[0070] Dissolve 1 g glucose in 100 ml deionized water, add 0.1 g tantalum phosphate solid acid TaP-600, stir at 160°C for 4 hours, then cool to room temperature. The reaction liquid is centrifuged at 10000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography, the molar yield of HMF is 14.4%.

[0071] Example 19 Preparation of HMF from glucose catalyzed by TaP-600 solid acid of tantalum phosphate

[0072] Dissolve 1 g of glucose in 100 ml of deionized water, add 0.1 g of TaP-600 solid acid of tantalum phosphate, stir at 180 °C for 4 hours, and then cool to room temperature. The reaction solution is centrifuged at 10,000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography. The molar yield of HMF is 22.9%.

[0073] Example 20 Preparation of HMF from glucose catalyzed by TaP-600 solid acid of tantalum phosphate

[0074] Dissolve 1 g of glucose in 100 ml of deionized water, add 0.1 g of TaP-600 solid acid of tantalum phosphate, stir at 190 °C for 4 hours, and then cool to room temperature. The reaction solution is centrifuged at 10,000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography. The molar yield of HMF is 16.6%.

[0075] Example 21 Preparation of HMF from glucose catalyzed by TaP-600 solid acid of tantalum phosphate

[0076] Dissolve 1 g of glucose in 100 ml of deionized water, add 0.2 g of TaP-600 solid acid of tantalum phosphate, stir at 170 °C for 4 hours, and then cool to room temperature. The reaction solution is centrifuged at 10,000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography. The molar yield of HMF is 20.2%.

[0077] Example 22 Preparation of HMF from glucose catalyzed by TaP-600 solid acid of tantalum phosphate

[0078] Dissolve 1 g of glucose in 100 ml of deionized water, add 0.05 g of TaP-600 solid acid of tantalum phosphate, stir at 170 °C for 4 hours, and then cool to room temperature. The reaction solution is centrifuged at 10,000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography. The molar yield of HMF is 17.7%.

[0079] Example 23 Preparation of HMF from glucose catalyzed by TaP-600 solid acid of tantalum phosphate

[0080] Dissolve 1 g of glucose in 100 ml of deionized water, add 0.034 g of TaP-600 solid acid of tantalum phosphate, stir at 170 °C for 4 hours, and then cool to room temperature. The reaction solution is centrifuged at 10,000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography. The molar yield of HMF is 14.6%.

[0081] Example 24 Preparation of HMF from glucose catalyzed by TaP-600 solid acid of tantalum phosphate

[0082] Dissolve 1 g of glucose in 100 ml of deionized water, add 0.025 g of TaP-600 solid acid of tantalum phosphate, stir and react at 170 °C for 4 hours, and then cool to room temperature. The reaction solution is centrifuged at 10 000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography. The molar yield of HMF is 7.7%.

[0083] Example 25 Preparation of HMF from glucose catalyzed by TaP-600 solid acid of tantalum phosphate

[0084] Dissolve 5 g of glucose in 100 ml of deionized water, add 0.1 g of TaP-600 solid acid of tantalum phosphate, stir and react at 170 °C for 4 hours, and then cool to room temperature. The reaction solution is centrifuged at 10 000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography. The molar yield of HMF is 15.5%.

[0085] Example 26 Preparation of HMF from glucose catalyzed by TaP-600 solid acid of tantalum phosphate

[0086] Dissolve 5 g of glucose in 100 ml of deionized water, add 0.025 g of TaP-600 solid acid of tantalum phosphate, stir and react at 170 °C for 4 hours, and then cool to room temperature. The reaction solution is centrifuged at 10 000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography. The molar yield of HMF is 9.3%.

[0087] Example 27 Preparation of HMF from glucose catalyzed by TaP-600 solid acid of tantalum phosphate

[0088] Dissolve 10 g of glucose in 100 ml of deionized water, add 0.1 g of TaP-600 solid acid of tantalum phosphate, stir and react at 170 °C for 4 hours, and then cool to room temperature. The reaction solution is centrifuged at 10 000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography. The molar yield of HMF is 11.5%.

[0089] Example 28 Preparation of HMF from glucose catalyzed by TaP-600 solid acid of tantalum phosphate

[0090] Dissolve 15 g of glucose in 100 ml of deionized water, add 0.1 g of TaP-600 solid acid of tantalum phosphate, stir and react at 170 °C for 4 hours, and then cool to room temperature. The reaction solution is centrifuged at 10 000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography. The molar yield of HMF is 10.7%.

[0091] Example 29 Preparation of HMF from glucose catalyzed by TaP-600 solid acid of phosphotungstic acid

[0092] Dissolve 5 g of glucose in 100 ml of deionized water, add 0.5 g of TaP-600 solid acid of phosphotungstic acid, stir at 170 °C for 2 hours, and then cool to room temperature. The reaction solution is centrifuged at 10,000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography, with a molar yield of HMF of 15.8%.

[0093] Example 30 Preparation of HMF from glucose catalyzed by TaP-600 solid acid of phosphotungstic acid

[0094] Dissolve 10 g of glucose in 100 ml of deionized water, add 1 g of TaP-600 solid acid of phosphotungstic acid, stir at 170 °C for 2 hours, and then cool to room temperature. The reaction solution is centrifuged at 10,000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography, with a molar yield of HMF of 12.6%.

[0095] Example 31 Preparation of HMF from glucose catalyzed by TaP-600 solid acid of phosphotungstic acid

[0096] Dissolve 15 g of glucose in 100 ml of deionized water, add 1.5 g of TaP-600 solid acid of phosphotungstic acid, stir at 170 °C for 2 hours, and then cool to room temperature. The reaction solution is centrifuged at 10,000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography, with a molar yield of HMF of 12.4%.

[0097] Example 32 Preparation of HMF from glucose catalyzed by TaP-600 solid acid of phosphotungstic acid

[0098] Dissolve 20 g of glucose in 100 ml of deionized water, add 2 g of TaP-600 solid acid of phosphotungstic acid, stir at 170 °C for 1 hour, and then cool to room temperature. The reaction solution is centrifuged at 10,000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography, with a molar yield of HMF of 9.7%.

[0099] Example 33 Preparation of HMF from glucose catalyzed by TaP-600 solid acid of phosphotungstic acid

[0100] Dissolve 3 g of glucose in 300 ml of deionized water, add 700 ml of methyl isobutyl ketone and 0.3 g of TaP-600 solid acid of phosphotungstic acid, stir at 170 °C for 4 hours, and then cool to room temperature. The reaction solution is centrifuged at 10,000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography, with a molar yield of HMF of 67.1%.

[0101] Example 34 Preparation of HMF from glucose catalyzed by TaP-600 solid acid of tantalum phosphate

[0102] Dissolve 15 g of glucose in 300 ml of deionized water, add 700 ml of methyl isobutyl ketone and 1.5 g of TaP-600 solid acid of tantalum phosphate, stir at 170 °C for 4 hours, and then cool to room temperature. The reaction solution is centrifuged at 10,000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography. The molar yield of HMF is 44.3%.

[0103] Example 35 Preparation of HMF from glucose catalyzed by TaP-600 solid acid of tantalum phosphate

[0104] Dissolve 30 g of glucose in 300 ml of deionized water, add 700 ml of methyl isobutyl ketone and 3 g of TaP-600 solid acid of tantalum phosphate, stir at 170 °C for 4 hours, and then cool to room temperature. The reaction solution is centrifuged at 10,000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography. The molar yield of HMF is 29.6%.

[0105] Example 36 Preparation of HMF from glucose catalyzed by TaP-600 solid acid of tantalum phosphate

[0106] Dissolve 45 g of glucose in 300 ml of deionized water, add 700 ml of methyl isobutyl ketone and 4.5 g of TaP-600 solid acid of tantalum phosphate, stir at 170 °C for 4 hours, and then cool to room temperature. The reaction solution is centrifuged at 10,000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography. The molar yield of HMF is 27.5%.

[0107] Example 37 Preparation of HMF from glucose catalyzed by TaP-600 solid acid of tantalum phosphate

[0108] Dissolve 60 g of glucose in 300 ml of deionized water, add 700 ml of methyl isobutyl ketone and 6 g of TaP-600 solid acid of tantalum phosphate, stir at 170 °C for 4 hours, and then cool to room temperature. The reaction solution is centrifuged at 10,000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography. The molar yield of HMF is 23.7%.

[0109] Example 38 Preparation of HMF from glucose catalyzed by TaP-600 solid acid of tantalum phosphate

[0110] 30 g glucose was dissolved in 300 ml deionized water, 700 ml methyl isobutyl ketone and 6 g solid acid TaP-600 were added, and the mixture was stirred at 170 °C for 5 h, and then cooled to room temperature. The reaction solution was centrifuged at 10 000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography. The molar yield of HMF was 33.8%.

[0111] Example 39 Preparation of HMF from glucose catalyzed by solid acid TaP-600

[0112] 1 mol of tantalum chloride was dissolved in 500 ml of ethanol, and the mixture was stirred at 80 °C for 4 h. After cooling to room temperature, 300 ml of ultrapure water, 150 g of citric acid, and 22.5 g of polyethylene glycol with a molecular weight of 35 000 were added. The mixture was stirred until homogeneous, and then 140 ml of concentrated phosphoric acid was added. The white solid obtained was exchanged with water, methanol, and n-hexane solvents, and dried under vacuum to obtain a phosphotungstic acid xerogel with a co-continuous macroporous structure. The phosphotungstic acid xerogel was calcined at 600 °C for 8 h in a high-temperature furnace to obtain the bifunctional catalyst TaP-600.

[0113] 30 g glucose was dissolved in 300 ml deionized water, 700 ml methyl isobutyl ketone and 10 g solid acid TaP-600 were added, and the mixture was stirred at 170 °C for 4 h, and then cooled to room temperature. The reaction solution was centrifuged at 10 000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography. The molar yield of HMF was 32.1%.

[0114] Example 40 Preparation of HMF from glucose catalyzed by solid acid TaP-600

[0115] The catalyst after reaction in Example 33 was centrifuged and calcined at 600 °C for 4 h as a recovered catalyst, which was denoted as TaP-600-2.

[0116] 3 g glucose was dissolved in 300 ml deionized water, 700 ml methyl isobutyl ketone and 0.3 g of recovered solid acid TaP-600-2 were added, and the mixture was stirred at 170 °C for 4 h, and then cooled to room temperature. The reaction solution was centrifuged at 10 000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography. The molar yield of HMF was 65.6%.

[0117] Example 41 Preparation of HMF from glucose catalyzed by solid acid TaP-600

[0118] The catalyst after reaction in Example 40 was centrifuged and calcined at 600 °C for 4 h as a recovered catalyst, which was denoted as TaP-600-3.

[0119] 3 g glucose was dissolved in 300 ml deionized water, 700 ml methyl isobutyl ketone and 0.3 g recovered tantalum phosphate solid acid TaP-600-3 were added, and the mixture was stirred at 170 °C for 4 h, and then cooled to room temperature. The reaction solution was centrifuged at 10000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography. The molar yield of HMF was 64.2%.

[0120] Example 42: Preparation of HMF from glucose catalyzed by tantalum phosphate solid acid TaP-600

[0121] The catalyst after reaction in Example 41 was centrifuged and calcined at 600 °C for 4 h as a recovered catalyst, which was denoted as TaP-600-4.

[0122] 3 g glucose was dissolved in 300 ml deionized water, 700 ml methyl isobutyl ketone and 0.3 g recovered tantalum phosphate solid acid TaP-600-4 were added, and the mixture was stirred at 170 °C for 4 h, and then cooled to room temperature. The reaction solution was centrifuged at 10000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography. The molar yield of HMF was 63.1%.

[0123] Comparative Example 1: Preparation of HMF from glucose catalyzed by phosphated tantalum hydroxide HO-TaP04 solid acid

[0124] The phosphated tantalum hydroxide HO-TaP04 solid acid catalyst was prepared according to the method disclosed in Example 1 of the published patent (CN 102477020 A).

[0125] 3 g glucose was dissolved in 300 ml deionized water, 700 ml methyl isobutyl ketone and 0.3 g phosphated tantalum hydroxide HO-TaP04 solid acid catalyst were added, and the mixture was stirred at 170 °C for 4 h, and then cooled to room temperature. The reaction solution was centrifuged at 10000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography. The molar yield of HMF was 55.4%.

[0126] Comparative Example 2: Preparation of HMF from glucose catalyzed by phosphated tantalum hydroxide HO-TaP04 solid acid

[0127] The phosphated tantalum hydroxide HO-TaP04 solid acid catalyst after reaction in Comparative Example 1 was centrifuged and calcined at 600 °C for 4 h as a recovered catalyst, which was denoted as HO-TaP04-2.

[0128] 3 g glucose was dissolved in 300 ml deionized water, 700 ml methyl isobutyl ketone and 0.3 g of phosphatized tantalum hydroxide HO-TaPO4-2 solid acid catalyst were added, and stirred at 170 ℃ for 4 h, and then cooled to room temperature. The reaction solution was centrifuged at 10000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography, the molar yield of HMF was 35.9%.

[0129] Comparative Example 3: Preparation of HMF from glucose catalyzed by phosphatized tantalum hydroxide HO-TaPO4 solid acid

[0130] The phosphatized tantalum hydroxide HO-TaPO4 solid acid catalyst after reaction in Comparative Example 3 was centrifuged and calcined at 600 ℃ for 4 h as a recovered catalyst, denoted as HO-TaPO4-3.

[0131] 3 g glucose was dissolved in 300 ml deionized water, 700 ml methyl isobutyl ketone and 0.3 g of phosphatized tantalum hydroxide HO-TaPO4-3 solid acid catalyst were added, and stirred at 170 ℃ for 4 h, and then cooled to room temperature. The reaction solution was centrifuged at 10000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography, the molar yield of HMF was 20.3%.

[0132] Comparative Example 4: Preparation of HMF from glucose catalyzed by phosphatized tantalum hydroxide HO-TaPO4 solid acid

[0133] The phosphatized tantalum hydroxide HO-TaPO4 solid acid catalyst after reaction in Comparative Example 3 was centrifuged and calcined at 600 ℃ for 4 h as a recovered catalyst, denoted as HO-TaPO4-4.

[0134] 3 g glucose was dissolved in 300 ml deionized water, 700 ml methyl isobutyl ketone and 0.3 g of phosphatized tantalum hydroxide HO-TaPO4-3 solid acid catalyst were added, and stirred at 170 ℃ for 4 h, and then cooled to room temperature. The reaction solution was centrifuged at 10000 r / min to remove the solid catalyst, and analyzed by high performance liquid chromatography, the molar yield of HMF was 20.3%.

[0135] Comparative Example 5

[0136] The conditions of CN202210016933.4 niobium phosphate oxide cannot react to obtain phosphatized tantalum hydroxide HO-TaPO4 catalyst.

Claims

1. A process for the catalytic dehydration of glucose to 5-hydroxymethylfurfural using a hierarchical porous bifunctional solid acid catalyst, characterized in that: The multi-level hole tantalum phosphate solid acid catalyst is heated with glucose in a water-methyl isobutyl ketone two-phase reaction system, the catalyst is separated by centrifugation after the reaction, and 5-hydroxymethyl furfural is obtained by purifying the product; the mass concentration of glucose in water is 1-10%; the heating reaction is carried out at 170-180 DEG C for 240-600 minutes; The molar ratio of citric acid to tantalum chloride is 0.25:1-0.78:1; The preparation method of the multi-level hole tantalum phosphate solid acid catalyst is as follows: tantalum chloride is dissolved in an ethanol solvent, and alkoxy tantalum is generated by reacting at 60-90 DEG C for 2-6 hours; the solution is cooled to room temperature, citric acid, polyethylene glycol and water are added and stirred until dissolved; concentrated phosphoric acid is finally added to react and gel; the organic acid and solvent in the gel are removed by solvent exchange and vacuum drying to obtain a tantalum phosphate xerogel material; the xerogel material is activated by being fully calcined at 600 DEG C to obtain a tantalum phosphate bifunctional solid acid catalyst.

2. The process for the dehydration of glucose to 5-hydroxymethylfurfural catalyzed by the hierarchical porous bifunctional solid acid catalyst according to claim 1, characterized in that: The amount of polyethylene glycol is 10-30 g / mol-tantalum chloride; the molar ratio of concentrated phosphoric acid to tantalum chloride is 1:1-4:

1.

3. The process for the dehydration of glucose to 5-hydroxymethylfurfural catalyzed by the hierarchical porous bifunctional solid acid catalyst according to claim 1, characterized in that: The volume ratio of ethanol solvent to water is 5:

3.

4. The process for the dehydration of glucose to 5-hydroxymethylfurfural catalyzed by the hierarchical porous bifunctional solid acid catalyst according to claim 1, characterized in that: The volume ratio of water to methyl isobutyl ketone is 1:1-1:

5.

5. The process for the dehydration of glucose to 5-hydroxymethylfurfural catalyzed by the hierarchical porous bifunctional solid acid catalyst according to claim 1, characterized in that: The mass ratio of multi-level hole tantalum phosphate solid acid catalyst to glucose is 1:5-1:40.

Images