A method for preparing fructose by modifying ordered mesoporous carbon materials with solid base and isomerizing glucose.

Abstract

This invention provides a method for preparing fructose by glucose isomerization using a solid base-modified ordered mesoporous carbon material, relating to the field of catalyst support technology. The solid base-modified ordered mesoporous carbon material of this invention consists of alkaline earth metal oxides dispersed within the ordered mesoporous carbon material, prepared using a two-step method: first, a precursor is prepared, then an alkaline earth metal salt is added for reaction. This method features a high number of total basic sites and a high number of weakly basic sites, exhibiting high catalytic activity for the glucose isomerization to fructose.

Description

Technical Field

[0001] This invention belongs to the field of catalyst support technology, and relates to a method for preparing fructose by modifying ordered mesoporous carbon materials with solid base and by isomerizing glucose. Background Technology

[0002] Fructose, an important hexose ketose, is the sweetest natural sweetener with a low glycemic index in the food industry. It is also a key raw material for the production of bio-based platform chemicals such as 5-hydroxymethylfurfural (5-HMF) and levulinic acid. Fructose is generally prepared from glucose through an isomerization reaction. MgO is a commonly used catalyst. Nano-sized magnesium oxide has high catalytic activity and good catalytic effect, but it is prone to aggregation, which leads to a decrease in catalytic performance.

[0003] Ordered mesoporous carbon (OMC) materials possess advantages such as high specific surface area, well-organized pore structure, good chemical stability, and tunable surface chemistry, making them ideal catalyst supports. Chinese patent CN111939891A discloses a tannin-based ordered mesoporous carbon catalyst. Tanninic acid, a surfactant, and magnesium nitrate hexahydrate undergo solvent evaporation self-assembly, followed by curing and high-temperature sintering to obtain the tannin-based ordered mesoporous carbon catalyst. This catalyst is used to catalyze the isomerization of glucose to produce fructose, exhibiting good catalytic activity and selectivity.

[0004] For MgO / OMC supported catalysts, the degree of exposure of active sites has a significant impact on catalytic performance; higher exposure results in better catalytic performance. However, the exposure of active sites in existing MgO / OMC supported catalysts is still insufficient. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method for preparing fructose by modifying ordered mesoporous carbon materials with a solid alkali and by isomerizing glucose.

[0006] The technical solution of the present invention is as follows:

[0007] A solid alkali-modified ordered mesoporous carbon material, wherein the solid alkali-modified ordered mesoporous carbon material is an alkaline earth metal oxide dispersed in the ordered mesoporous carbon material; The solid alkali-modified ordered mesoporous carbon material was tested with CO2-TPD, and the total number of basic sites was not less than 0.25 mmol / g, and the number of weakly basic sites was not less than 0.05 mmol / g. The BET specific surface area of ​​the solid alkali-modified ordered mesoporous carbon material is not less than 150 m². 2 / g, with an average pore size of 3-5nm.

[0008] Preferably, the solid alkali-modified ordered mesoporous carbon material is tested using Raman spectroscopy, and the ID / IG ratio is ≥2.5.

[0009] Preferably, the alkaline earth metal oxide is selected from one or both of magnesium oxide and calcium oxide.

[0010] Preferably, the preparation method of the solid alkali-modified ordered mesoporous carbon material is as follows: Nonionic surfactants and organic carbon sources are added to an organic solvent, dissolved uniformly, and allowed to stand at room temperature for solvent evaporation and self-assembly to obtain an organic mesoporous precursor solution. Alkaline earth metal salts are added to the organic mesoporous precursor solution, stirred and dispersed evenly, and then cured and carbonized at high temperature to obtain the solid alkali-modified ordered mesoporous carbon material.

[0011] More preferably, the nonionic surfactant is selected from Pluronic nonionic surfactants; The organic carbon source is selected from aromatic carboxylic acids or phenolic organic compounds.

[0012] More preferably, the weight ratio of the nonionic surfactant to the organic carbon source is 1:0.5-4.

[0013] More preferably, the organic solvent is selected from C1-C4 alcohol solvents; The ratio of the sum of the weights of the nonionic surfactant and the organic carbon source to the weight of the alkaline earth metal salt is 10:0.5-3.

[0014] More preferably, the alkaline earth metal salt is selected from one or more of magnesium nitrate, magnesium chloride, magnesium sulfate, magnesium acetate, calcium nitrate, and calcium chloride.

[0015] A method for preparing fructose by glucose isomerization involves adding a solid alkali as described in any of the above embodiments to an aqueous glucose solution to modify an ordered mesoporous carbon material for reaction, thereby obtaining fructose.

[0016] Preferably, the concentration of the glucose aqueous solution is 10-50 wt%; The weight of the solid alkali-modified ordered mesoporous carbon material is 5-25% of the weight of glucose in the glucose aqueous solution.

[0017] The beneficial effects of this invention are: (1) The present invention uses a “two-step method” to prepare catalysts. First, an organic mesoporous precursor is prepared, and then it is mixed and loaded with alkaline earth metal salts. After solidification and sintering, a solid base modified ordered mesoporous carbon material with high catalytic activity is obtained. Compared with the existing “one-pot method” (such as the solvent evaporation self-assembly of tannic acid, surfactant and magnesium nitrate hexahydrate as described in CN111939891A) to prepare mesoporous carbon material catalysts, the catalyst obtained under the same amount of alkaline earth metal salts has more active sites exposed, especially more weakly basic active sites.

[0018] (2) The solid base modified ordered mesoporous carbon material of the present invention is used to catalyze the isomerization of glucose to fructose. The glucose conversion rate, fructose yield and fructose selectivity are all high, showing that the catalyst has excellent catalytic activity. It is also easy to recover and can be reused multiple times. Attached Figure Description

[0019] Figure 1 SEM images of the ordered mesoporous carbon materials prepared in Examples 1, 2, 3 and Comparative Example 1, and elemental surface scan images of Example 2.

[0020] Figure 2 XPS spectra of the ordered mesoporous carbon materials prepared in Examples 1, 2, 3 and Comparative Example 1.

[0021] Figure 3 The FT-IR and Raman spectra of the ordered mesoporous carbon materials prepared in Examples 1, 2, 3 and Comparative Example 1 are shown. Detailed Implementation

[0022] The technical solution of the present invention will be further explained and described below through specific embodiments.

[0023] On the one hand, the present invention proposes a solid alkali modified ordered mesoporous carbon material, wherein the solid alkali modified ordered mesoporous carbon material is an alkaline earth metal oxide dispersed in the ordered mesoporous carbon material; The ordered mesoporous carbon material modified with solid base was tested with CO2-TPD, and the total number of basic sites was not less than 0.25 mmol / g, and the number of weakly basic sites was not less than 0.05 mmol / g. Solid alkali-modified ordered mesoporous carbon materials have a BET specific surface area of ​​no less than 150 m². 2 / g, with an average pore size of 3-5nm.

[0024] The solid base-modified ordered mesoporous carbon material of this invention consists of alkaline earth metal oxides dispersed within the ordered mesoporous carbon material. It possesses a high number of basic active sites and weakly basic sites. The high number of weakly basic sites is beneficial for improving glucose conversion, fructose yield, and fructose selectivity. A high specific surface area also contributes to improved catalytic activity. Furthermore, the BET specific surface area of ​​the solid base-modified ordered mesoporous carbon material of this invention is not less than 200 m². 2 / g, or not less than 250m 2 / g, or not less than 300m 2 / g, and can even reach 350m 2 Approximately / g.

[0025] In some embodiments, the solid base-modified ordered mesoporous carbon material is measured using Raman spectroscopy, with an ID / IG ratio ≥ 2.5. ID / IG is used to semi-quantitatively characterize the defect degree of the solid base-modified ordered mesoporous carbon material. The defect degree shows a strong positive correlation with the active sites; a higher ID / IG value indicates a higher defect degree, which is more conducive to the exposure of catalytic active sites. For example, ID / IG values ​​can be 2.5, 2.53, 2.55, 2.6, 2.65, 2.68, 2.7, 2.75, 2.8, etc.

[0026] In some embodiments, the alkaline earth metal oxide is selected from one or both of magnesium oxide and calcium oxide. Magnesium oxide and calcium oxide have suitable basicity, making them suitable as catalysts for the isomerization of glucose to fructose.

[0027] In some embodiments, the method for preparing solid alkali-modified ordered mesoporous carbon materials is as follows: Nonionic surfactants and organic carbon sources are added to an organic solvent, dissolved uniformly, and allowed to stand at room temperature for solvent evaporation and self-assembly to obtain an organic mesoporous precursor solution. Alkaline earth metal salts are added to an organic mesoporous precursor solution, stirred and dispersed evenly, and then cured and carbonized at high temperature to obtain solid alkali-modified ordered mesoporous carbon materials.

[0028] This invention employs a two-step method to prepare solid alkali-modified ordered mesoporous carbon materials. First, a precursor is formed by solvent evaporation and self-assembly of a nonionic surfactant and an organic carbon source. Then, an alkaline earth metal salt is added, which is dispersed in the precursor in a nano-form. After solidification and high-temperature sintering, the resulting solid alkali-modified ordered mesoporous carbon material can expose more weakly basic active sites compared to existing one-pot prepared mesoporous carbon catalysts. When applied to the catalysis of glucose isomerization to fructose, it can improve the conversion rate of glucose, the yield of fructose, and the selectivity of fructose. Furthermore, it reduces the number of strongly basic active sites, avoiding side reactions or other adverse effects caused by excessive strongly basic active sites, such as decreased fructose selectivity and catalyst deactivation.

[0029] In the above-mentioned method for preparing ordered mesoporous carbon materials modified with solid alkali, there are no particular restrictions on the curing conditions, such as heating at 100℃ for 24 hours; there are no particular restrictions on the high-temperature carbonization conditions, such as carbonization temperature of 550-850℃ and time of 0.5-3 hours.

[0030] In some embodiments, the nonionic surfactant is selected from Pluronic nonionic surfactants; The organic carbon source is selected from aromatic carboxylic acids or phenolic organic compounds.

[0031] For example, nonionic surfactants can be Pluronic F127, Pluronic P123, Pluronic F108, etc., aromatic carboxylic acids can be ferulic acid, caffeic acid, trimellitic acid, trimellitic acid, 2,4-dihydroxybenzoic acid, etc., and phenolic organic compounds can be hydroquinone, phenol, phenolic resin, 2,3-dihydroxynaphthalene, etc.

[0032] In some embodiments, the weight ratio of nonionic surfactant to organic carbon source is 1:0.5-4. For example, the weight ratio of nonionic surfactant to organic carbon source can be 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, etc.

[0033] In some embodiments, the organic solvent is selected from C1-C4 alcohol solvents; The ratio of the sum of the weights of the nonionic surfactant and the organic carbon source to the weight of the alkaline earth metal salt is 10:0.5-3.

[0034] For example, the organic solvent can be methanol, ethanol, isopropanol, butanol, isobutanol, etc. There are no particular restrictions on the concentration of the nonionic surfactant in the organic solvent; for example, it can be 1-5 g / 100 ml. When adding the nonionic surfactant and organic carbon source to the organic solvent, they can be added simultaneously and dissolved together, or the nonionic surfactant and organic carbon source can be separately added to the organic solvent to prepare nonionic surfactant solutions and organic carbon source solutions, respectively, and then mixed to form a final solution.

[0035] For example, the weight ratio of the sum of the nonionic surfactant and organic carbon source to the weight of the alkaline earth metal salt can be 10:0.5, 10:1, 10:1.5, 10:2, 10:2.5, 10:3, etc. The more alkaline earth metal salt added, the more alkaline earth metal oxides are formed on the surface of the solid alkali-modified ordered mesoporous carbon material, resulting in more catalytic active sites. However, excessive alkaline earth metal oxides may disrupt the ordered structure of the ordered mesoporous carbon material, or lead to a significant decrease in the BET specific surface area of ​​the solid alkali-modified ordered mesoporous carbon material, or result in an excessive number of strongly basic active sites, which is detrimental to catalytic activity, or to the yield and / or selectivity of fructose. Furthermore, the weight ratio of the sum of the nonionic surfactant and organic carbon source to the weight of the alkaline earth metal salt can be 10:1-2.

[0036] In some embodiments, the alkaline earth metal salt is selected from one or more of magnesium nitrate, magnesium chloride, magnesium sulfate, magnesium acetate, calcium nitrate, and calcium chloride.

[0037] On the other hand, the present invention also proposes a method for preparing fructose by glucose isomerization, wherein a solid base as described in any of the above embodiments is added to a glucose aqueous solution to modify an ordered mesoporous carbon material for reaction, thereby obtaining fructose.

[0038] The solid base-modified ordered mesoporous carbon material of this invention has the characteristics of high specific surface area, relatively large number of weakly basic active sites and relatively small number of strongly basic active sites, making it suitable as a catalyst for the isomerization of glucose to fructose. It has the characteristics of high glucose conversion rate, high fructose yield and high fructose selectivity.

[0039] In some embodiments, the concentration of the glucose aqueous solution is 10-50 wt%; The weight of the solid alkali-modified ordered mesoporous carbon material is 5-25% of the weight of glucose in the glucose aqueous solution.

[0040] In this invention, the concentration of the glucose aqueous solution can be relatively high, which is beneficial for industrial production. For example, the concentration of the glucose aqueous solution can be 10wt%, 20wt%, 30wt%, 40wt%, 50wt%, etc., and the weight of the solid alkali-modified ordered mesoporous carbon material is 5%, 10%, 15%, 20%, 25% of the weight of glucose in the glucose aqueous solution, etc.

[0041] In the above method for preparing fructose by glucose isomerization, the reaction temperature can be 70-120℃, and the reaction time can be 0.5-6 h. After the reaction, the catalyst solid base modified with ordered mesoporous carbon material can be separated, washed with deionized water, dried, and then recycled.

[0042] The technical solution of the present invention will be further described and illustrated below with reference to various embodiments. Unless otherwise specified, the parts mentioned in the following embodiments are parts by weight.

[0043] Example 1 2.5g of F127 was added to 50 mL of anhydrous ethanol, sonicated for 10 min, and stirred at room temperature for 2 h to obtain solution A; 2.5g of ferulic acid was added to 50 mL of anhydrous ethanol and stirred to dissolve, yielding solution B; Solution A was added dropwise to solution B, and then gently stirred for 2 h to allow solvent evaporation and self-assembly, thus obtaining an organic mesoporous precursor solution. 0.5 g of magnesium nitrate hexahydrate was added to the organic mesoporous precursor solution and stirred for 2 h. Then, the solution was allowed to stand for 12 h to evaporate ethanol. The solution was then heated to 100 °C for 24 h to solidify. The solution was then heated to 350 °C at a heating rate of 3 °C / min and held for 1 h. The solution was then heated to 750 °C at a heating rate of 5 °C / min and held for 2 h. The solution was allowed to cool naturally and then ground to obtain a solid alkali-modified ordered mesoporous carbon material, denoted as 10%MgO@OMC, where 10% represents the weight ratio of magnesium nitrate hexahydrate (0.5 g) to F127 and ferulic acid (5 g).

[0044] Example 2 The difference between this embodiment and Example 1 is that in Example 1, the amount of magnesium nitrate hexahydrate was adjusted from 0.5g to 1g. All other steps remained unchanged. The obtained solid alkali-modified ordered mesoporous carbon material was designated as 20%MgO@OMC.

[0045] Example 3 The difference between this embodiment and Example 1 is that in Example 1, the amount of magnesium nitrate hexahydrate was adjusted from 0.5g to 1.5g. The remaining steps remained unchanged. The obtained solid alkali-modified ordered mesoporous carbon material was designated as 30%MgO@OMC.

[0046] Comparative Example 1 The difference between this comparative example and Example 1 is that in Example 1, magnesium nitrate hexahydrate was not added, and ethanol was directly evaporated for 12 hours after obtaining the organic mesoporous precursor solution. The remaining steps remained unchanged. The obtained ordered mesoporous carbon material is denoted as OMC.

[0047] The SEM morphology results of OMC, 10%MgO@OMC, 20%MgO@OMC, and 30%MgO@OMC are attached. Figure 1 As shown in the figure, Figure a represents OMC, Figure b represents 10% MgO@OMC, Figure c represents 20% MgO@OMC, and Figure d represents 30% MgO@OMC, demonstrating that the mesoporous carbon material does not exhibit significant agglomeration.

[0048] Figure e shows the surface scan of C, O, and Mg elements in 20%MgO@OMC, indicating that the distribution of each element is relatively uniform.

[0049] Figure 2 The figures show XPS spectra of OMC, 10%MgO@OMC, 20%MgO@OMC, and 30%MgO@OMC. Figure a is the full XPS spectrum with high resolution; Figure b is the XPS spectrum of C 1s; Figure c is the XPS spectrum of O 1s; and Figure d is the XPS spectrum of Mg 2p, showing Mg-O and Mg-OH bonds.

[0050] Figure 3 Figure 1 shows the FT-IR and Raman spectra of OMC, 10%MgO@OMC, 20%MgO@OMC, and 30%MgO@OMC, where Figure 2a is the FT-IR spectrum and Figure 2b is the Raman spectrum.

[0051] Comparative Example 2 The difference from Example 2 is that a "one-pot method" is used to prepare solid alkali-modified ordered mesoporous carbon materials.

[0052] 2.5g of F127 was added to 50 mL of anhydrous ethanol, sonicated for 10 min, and stirred at room temperature for 2 h to obtain solution A; 2.5g of ferulic acid was added to 50 mL of anhydrous ethanol and stirred to dissolve, yielding solution B; Solution A was added dropwise to solution B, followed by the addition of 1 g of magnesium nitrate hexahydrate. The mixture was stirred for 2 h to allow solvent evaporation and self-assembly. The mixture was then allowed to stand for 12 h to evaporate ethanol. After that, it was heated at 100 °C for 24 h to solidify. Then, it was heated to 350 °C at a rate of 3 °C / min and held for 1 h. The temperature was then increased to 750 °C at a rate of 5 °C / min and held for 2 h. After natural cooling, the mixture was ground to obtain a solid alkali-modified ordered mesoporous carbon material, denoted as 20%MgO@OMC-1.

[0053] The performance comparison of 20% MgO@OMC in Example 2 and 20% MgO@OMC-1 in Comparative Example 2 is shown in Table 1 below. The surface MgO content was determined by XPS testing.

[0054] Table 1

[0055] As can be seen from the data results in Table 1 above, the solid alkali-modified ordered mesoporous carbon material prepared by the "two-step method" of this invention has a higher specific surface area, a higher surface MgO content, a greater number of weakly basic sites, and a smaller number of strongly basic sites compared to the "one-pot method".

[0056] Catalyst performance evaluation 250 mg of glucose and 20 mg of catalyst were added to 5 ml of water, and the mixture was heated to 100 °C and reacted for 2 h. The glucose conversion rate, fructose yield and fructose selectivity were tested, and the results are shown in Table 2 below.

[0057] Glucose conversion rate = (moles of glucose before reaction - moles of glucose after reaction) / moles of glucose before reaction × 100%; Fructose yield = (moles of fructose / moles of glucose before reaction) × 100%; Fructose selectivity = (number of moles of fructose / (number of moles of glucose before reaction - number of moles of glucose after reaction)) × 100%.

[0058] Table 2

[0059] Based on Tables 1 and 2, and comparing Example 2 and Comparative Example 2, the solid alkali-modified ordered mesoporous carbon material of the present invention has a higher specific surface area, a higher surface MgO content, a greater number of weakly basic sites and a smaller number of strongly basic sites, and higher glucose conversion rate, fructose yield and fructose selectivity.

[0060] Example 4 2.5g of P123 was added to 50 mL of anhydrous ethanol, sonicated for 10 min, and stirred at room temperature for 2 h to obtain solution A; 5g of hydroquinone was added to 50 mL of anhydrous ethanol and stirred to dissolve, yielding solution B. Solution A was added dropwise to solution B, and then gently stirred for 2 h to allow solvent evaporation and self-assembly, thus obtaining an organic mesoporous precursor solution. 1.5 g of magnesium chloride was added to the organic mesoporous precursor solution and stirred for 2 h. Then, the solution was allowed to stand for 12 h to evaporate ethanol. The solution was then heated to 100 °C for 24 h to solidify. The solution was then heated to 350 °C at a heating rate of 3 °C / min and held for 1 h. The solution was then heated to 650 °C at a heating rate of 5 °C / min and held for 3 h. The solution was allowed to cool naturally and then ground to obtain a solid alkali-modified ordered mesoporous carbon material, denoted as 20%MgO@OMC-2.

[0061] Example 5 2.5g of P123 was added to 50 mL of anhydrous ethanol, sonicated for 10 min, and stirred at room temperature for 2 h to obtain solution A; 5g of dihydroxybenzoic acid was added to 50 mL of anhydrous ethanol and stirred to dissolve, yielding solution B. Solution A was added dropwise to solution B, and then gently stirred for 2 h to allow solvent evaporation and self-assembly, thus obtaining an organic mesoporous precursor solution. 1.5 g of calcium chloride was added to the organic mesoporous precursor solution and stirred for 2 h. Then, the solution was allowed to stand for 12 h to evaporate ethanol. The solution was then heated to 100 °C for 24 h to solidify. The solution was then heated to 350 °C at a heating rate of 3 °C / min and held for 1 h. The solution was then heated to 700 °C at a heating rate of 5 °C / min and held for 2.5 h. The solution was allowed to cool naturally and then ground to obtain a solid alkali-modified ordered mesoporous carbon material, denoted as 20%CaO@OMC.

[0062] Example 6 The difference between this embodiment and Example 5 is that in Example 5, calcium chloride was replaced with magnesium nitrate hexahydrate. The remaining steps remained unchanged, resulting in a solid alkali-modified ordered mesoporous carbon material, denoted as 20%MgO@OMC-3.

[0063] Performance tests are shown in Tables 3 and 4 below.

[0064] Table 3

[0065] Table 4

[0066] Based on the data in Tables 3 and 4, it can be seen that the solid alkali-modified ordered mesoporous carbon material of the present invention has a high specific surface area and surface MgO content, as well as a large number of weakly basic sites and a small number of strongly basic sites, which is beneficial to improving glucose conversion rate, fructose yield and fructose selectivity.

[0067] Compared with Example 2, Example 3 has a high surface MgO content, which leads to a significant decrease in specific surface area. However, it still has a large number of weakly basic sites, which improves glucose conversion rate, fructose yield and fructose selectivity.

[0068] As described above, the basic principles, main features, and advantages of the present invention have been shown and described. Those skilled in the art should understand that the present invention is not limited to the above embodiments, which are merely preferred embodiments and should not be construed as limiting the scope of the invention. All equivalent changes and modifications made in accordance with the scope of the patent and the description should still fall within the scope of the present invention. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A solid alkali-modified ordered mesoporous carbon material, characterized in that, The solid alkali-modified ordered mesoporous carbon material is an alkaline earth metal oxide dispersed in the ordered mesoporous carbon material. The solid alkali-modified ordered mesoporous carbon material was tested with CO2-TPD, and the total number of basic sites was not less than 0.25 mmol / g, and the number of weakly basic sites was not less than 0.05 mmol / g. The BET specific surface area of ​​the solid alkali-modified ordered mesoporous carbon material is not less than 150 m². 2 / g, with an average pore size of 3-5nm.

2. The solid alkali-modified ordered mesoporous carbon material according to claim 1, characterized in that, The solid alkali-modified ordered mesoporous carbon material was tested using Raman spectroscopy, and the ID / IG ratio was ≥2.

5.

3. The solid alkali-modified ordered mesoporous carbon material according to claim 1, characterized in that, The alkaline earth metal oxide is selected from one or both of magnesium oxide and calcium oxide.

4. The solid alkali-modified ordered mesoporous carbon material according to claim 1, characterized in that, The preparation method of the solid alkali-modified ordered mesoporous carbon material is as follows: Nonionic surfactants and organic carbon sources are added to an organic solvent, dissolved uniformly, and allowed to stand at room temperature for solvent evaporation and self-assembly to obtain an organic mesoporous precursor solution. Alkaline earth metal salts are added to the organic mesoporous precursor solution, stirred and dispersed evenly, and then cured and carbonized at high temperature to obtain the solid alkali-modified ordered mesoporous carbon material.

5. The solid alkali-modified ordered mesoporous carbon material according to claim 4, characterized in that, The nonionic surfactant is selected from Pluronic nonionic surfactants; The organic carbon source is selected from aromatic carboxylic acids or phenolic organic compounds.

6. The solid alkali-modified ordered mesoporous carbon material according to claim 4, characterized in that, The weight ratio of the nonionic surfactant to the organic carbon source is 1:0.5-4.

7. The solid alkali-modified ordered mesoporous carbon material according to claim 4, characterized in that, The organic solvent is selected from C1-C4 alcohol solvents; The ratio of the sum of the weights of the nonionic surfactant and the organic carbon source to the weight of the alkaline earth metal salt is 10:0.5-3.

8. The solid alkali-modified ordered mesoporous carbon material according to claim 4, characterized in that, The alkaline earth metal salt is selected from one or more of magnesium nitrate, magnesium chloride, magnesium sulfate, magnesium acetate, calcium nitrate, and calcium chloride.

9. A method for preparing fructose by isomerization of glucose, characterized in that, Fructose is obtained by adding the solid alkali described in any one of claims 1-8 to a glucose aqueous solution to modify the ordered mesoporous carbon material and reacting it.

10. The method for preparing fructose by glucose isomerization according to claim 9, characterized in that, The concentration of the glucose aqueous solution is 10-50 wt%; The weight of the solid alkali-modified ordered mesoporous carbon material is 5-25% of the weight of glucose in the glucose aqueous solution.

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