Heterogeneous catalyst and its application in catalyzing isomerization of glucose to fructose

Abstract

The present invention belongs to the field of glucose isomerization, and specifically relates to a heterogeneous catalyst and its application in catalyzing glucose isomerization to fructose. The heterogeneous catalyst is prepared in the following manner: a metal organic framework material and a Lewis acid metal ion solution are evenly mixed, and after the heating reaction is completed, the solution is washed and dried to obtain a heterogeneous catalyst; the concentration of the Lewis acid metal ion is 0.05-1M. The catalytic effect of the heterogeneous catalyst reaches a fructose yield of more than 30%, and the selectivity reaches more than 60%, thereby improving the catalytic effect. As a preferred form thereof, the catalytic effect reaches a fructose yield of more than 40%, and the selectivity reaches more than 80%.

Description

Technical Field

[0001] The invention belongs to the field of glucose isomerization, and particularly relates to a heterogeneous catalyst and an application thereof in catalyzing the isomerization of glucose into fructose. Background Art

[0002] Biomass energy is a sustainable resource that can replace traditional fossil energy to produce fuels and chemicals. The conversion of biomass resources into value-added chemicals such as biofuels and polymers can be achieved through "platform compounds", which include C6 sugars (glucose and fructose) and C5 sugars (xylose, etc.).

[0003] In the application of biomass energy, the isomerization of glucose to fructose is a key step in chemical production. The traditional catalytic methods for this reaction are bio-enzyme catalysis and chemical catalysis. However, the operating conditions of the enzyme catalysis method are harsh, and the enzyme needs to be replaced regularly; homogeneous acids or bases have the limitations of low selectivity, difficult separation and low repeatability; heterogeneous catalysts and reactants are in different phases, which makes it easy to separate the catalyst after the reaction and purify the product. Summary of the invention

[0004] The purpose of the present invention is to provide a heterogeneous catalyst and application thereof in catalyzing the isomerization of glucose into fructose.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A heterogeneous catalyst is prepared by the following method: a metal organic framework material and a Lewis acid metal ion solution are uniformly mixed, and after the heating reaction is completed, the mixture is washed and dried to obtain the heterogeneous catalyst; the concentration of the Lewis acid metal ion is 0.05-1M.

[0007] The concentration of the Lewis acid metal ion is 0.1-0.2M.

[0008] The Lewis acid metal ion is Al 3+ or Sn 4+ .

[0009] The metal organic framework material powder is prepared in the following manner: zirconium oxynitrate, TCPB-Br2 ligand, formic acid and N,N-dimethylformamide are put into a reaction container in a molar ratio of 29:5:1:4, reacted at 100°C for 16 hours, and centrifuged, washed and dried after the reaction to obtain the metal organic framework material.

[0010] The present invention also includes an application of the heterogeneous catalyst in catalyzing the isomerization of glucose into fructose.

[0011] The method specifically comprises the following steps: adding a heterogeneous catalyst to a heated glucose solution, filling with N2 and exhausting the air, reacting at 70-100° C., filtering after the reaction to obtain a solid and a filtrate, adding deionized water of an equal volume to the filtrate to carry out a hydrolysis reaction; wherein the mass ratio of the heterogeneous catalyst to the glucose in the glucose solution is 5-15:40.

[0012] The solvent of the glucose solution is ethanol or n-propanol.

[0013] The hydrolysis reaction time is 24h and the hydrolysis temperature is 90°C.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention successfully prepares a heterogeneous catalyst of a metal organic framework material loaded with Lewis acid metal sites. The heterogeneous catalyst of the present invention has the characteristics of stability, easy separation and high repeatability. The catalytic effect of the heterogeneous catalyst reaches a fructose yield of more than 30%, and the selectivity reaches more than 60%, thereby improving the catalytic effect. As a preferred form thereof, the catalytic effect reaches a fructose yield of more than 40%, and the selectivity reaches more than 80%. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Scanning electron microscope images, including (a) NU-1008; (b) 1Sn@NU-1008; (c) 0.5Al@NU-1008. DETAILED DESCRIPTION

[0017] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and the best embodiments.

[0018] Example 1: The metal organic framework material NU-1008 was prepared by the following method: zirconium oxynitrate, TCPB-Br2 ligand, formic acid, and N,N-dimethylformamide were added into a reaction vessel in a molar ratio of 29:5:1:4, and reacted at 100°C for 16 hours. After the reaction, the metal organic framework material ( Figure 1 a).

[0019] Example 2: A method for preparing a heterogeneous catalyst comprises the following steps: 40 mg of NU-1008 powder prepared in Example 1 (see Figure 1 a) and 4mL, 0.05M, 0.1M, 0.2M, 0.5M, 1M, Sn 4+The solution (SnCl4·5H2O prepared with solvent N, N-dimethylformamide) was mixed evenly, reacted at 100°C for 12 hours, washed with fresh N, N-dimethylformamide until the product was colorless, soaked in acetone overnight and washed by centrifugation three times; vacuum dried to obtain heterogeneous catalysts (0.05Sn@NU-1008, 0.1Sn@NU-1008, 0.2Sn@NU-1008, 0.5Sn@NU-1008, 1Sn@NU-1008, 0.05Sn@NU-1008 see Figure 1 b, 0.1Sn@NU-1008, 0.2Sn@NU-1008, 0.5Sn@NU-1008, 1Sn@NU-1008 particle size and Figure 1 b similar).

[0020] Example 3: A method for preparing a heterogeneous catalyst comprises the following steps: 40 mg of the activated NU-1008 powder prepared in Example 1 (see Figure 1 a) and 4 mL, 0.1 M, 0.2 M, 0.5 M Al 3+ The solution (a solution of AlCl3·6H2O prepared with solvent N, N-dimethylformamide) was mixed evenly, reacted at 100°C for 12 hours, washed with fresh N, N-dimethylformamide until the product was colorless, and then soaked in acetone overnight and washed by centrifugation three times; vacuum dried to obtain heterogeneous catalysts (0.1Al@NU-1008, 0.2Al@NU-1008, 0.5Al@NU-1008, 0.1Al@NU-1008 see Figure 1 c, 0.2Al@NU-1008, 0.5Al@NU-1008 particle size and Figure 1 c similar).

[0021] Example 4: Application of heterogeneous catalyst to catalyze isomerization of glucose to fructose: comprising the following steps: adding 5 mg of heterogeneous catalyst prepared in Example 2-3 to 70°C, 5 mL, 8 mg / mL glucose solution, filling with N2 and exhausting air, reacting at 70°C, at a speed of 600 rpm for 8 hours, filtering to obtain solid and filtrate, adding deionized water of the same volume as the filtrate to the filtrate, and hydrolyzing at 70°C, at a speed of 600 rpm for 24 hours. The fructose yield and fructose selectivity are shown in Table 1. The solvent of the glucose solution is ethanol.

[0022] Table 1 shows the application and results of Examples 2-3 in isomerizing glucose to fructose under the conditions of Example 4.

[0023] Table 1

[0024]

[0025] Among them, the experiment confirmed that the heterogeneous catalysts of 0.1Al@NU-1008 and 0.2Al@NU-1008 had the best catalytic effect. Therefore, they were used as preferred examples to test the application conditions for catalyzing the isomerization of glucose into fructose.

[0026] Example 5: Application of heterogeneous catalyst to catalyze isomerization of glucose into fructose: comprising the following steps: adding 5 mg of heterogeneous catalyst 0.1Al@NU-1008 prepared in Example 3 to 80°C, 5 mL, 8 mg / mL glucose solution, filling with N2 and exhausting air, reacting at 80°C, at a speed of 600 rpm for 10 h, filtering to obtain solid and filtrate, adding deionized water of the same volume as the filtrate to the filtrate, and hydrolyzing at 80°C, at a speed of 600 rpm for 24 h. The fructose yield and fructose selectivity are shown in Table 2. The solvent of the glucose solution is ethanol.

[0027] Example 6: Application of heterogeneous catalyst to catalyze isomerization of glucose into fructose: comprising the following steps: adding 5 mg of heterogeneous catalyst 0.1Al@NU-1008 prepared in Example 3 to 5 mL of 8 mg / mL glucose solution at 90°C, filling with N2 and exhausting the air, reacting at 90°C and 600 rpm for 12 h, filtering to obtain solid and filtrate, adding deionized water of the same volume as the filtrate to the filtrate, and hydrolyzing at 80°C and 600 rpm for 24 h. The fructose yield and fructose selectivity are shown in Table 2. The solvent of the glucose solution is ethanol.

[0028] Example 7: Application of heterogeneous catalyst to catalyze isomerization of glucose to fructose: comprising the following steps: adding 5 mg of heterogeneous catalyst 0.1Al@NU-1008 prepared in Example 3 to 100°C, 5 mL, 8 mg / mL glucose solution, filling with N2 and exhausting air, reacting at 100°C and 600 rpm for 9 h, filtering to obtain solid and filtrate, adding deionized water of equal volume to the filtrate to the filtrate, and hydrolyzing at 80°C and 600 rpm for 24 h. The fructose yield and fructose selectivity are shown in Table 2. The solvent of the glucose solution is n-propanol.

[0029] Example 8: Application of heterogeneous catalyst to catalyze isomerization of glucose into fructose: comprising the following steps: adding 10 mg of heterogeneous catalyst 0.1Al@NU-1008 prepared in Example 3 to 90°C, 5 mL, 8 mg / mL glucose solution, filling with N2 and exhausting air, reacting at 90°C, at a speed of 600 rpm for 12 h, filtering to obtain solid and filtrate, adding deionized water of the same volume as the filtrate to the filtrate, and hydrolyzing at 90°C, at a speed of 600 rpm for 24 h. The fructose yield and fructose selectivity are shown in Table 2. The solvent of the glucose solution is ethanol.

[0030] Example 9: Application of heterogeneous catalyst to catalyze isomerization of glucose into fructose: comprising the following steps: adding 15 mg of heterogeneous catalyst 0.1Al@NU-1008 prepared in Example 3 to 90°C, 5 mL, 8 mg / mL glucose solution, filling with N2 and exhausting air, reacting at 90°C, at a speed of 600 rpm for 12 h, filtering to obtain solid and filtrate, adding deionized water of the same volume as the filtrate to the filtrate, and hydrolyzing at 90°C, at a speed of 600 rpm for 24 h. The fructose yield and fructose selectivity are shown in Table 2. The solvent of the glucose solution is ethanol.

[0031] Example 10: Application of heterogeneous catalyst to catalyze isomerization of glucose into fructose: comprising the following steps: adding 15 mg of heterogeneous catalyst 0.2Al@NU-1008 prepared in Example 3 to 90°C, 5 mL, 8 mg / mL glucose solution, filling with N2 and exhausting air, reacting at 90°C, at a speed of 600 rpm for 12 h, filtering to obtain solid and filtrate, adding deionized water of the same volume as the filtrate to the filtrate, and hydrolyzing at 90°C, at a speed of 600 rpm for 24 h. The fructose yield and fructose selectivity are shown in Table 2. The solvent of the glucose solution is ethanol.

[0032] Table 2

[0033] project Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Fructose yield 40％ 47％ 39％ 56％ 59％ 60％ Fructose selectivity 85％ 91％ 84％ 93％ 87％ 89％

[0034] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a heterogeneous catalyst for catalyzing the isomerization of glucose into fructose, characterized in that: The preparation method is as follows: the metal organic framework material and the Lewis acid metal ion solution are mixed evenly, and after the heating reaction is completed, the solution is washed and dried to obtain a heterogeneous catalyst; the concentration of the Lewis acid metal ion is 0.05-1M; The Lewis acid metal ion is Al 3+ or Sn 4+ ; The metal organic framework material is prepared by the following method: zirconium oxynitrate, TCPB-Br2 ligand, formic acid, and N, N-dimethylformamide are put into a reaction container in a molar ratio of 29:5:1:4, reacted at 100°C for 16 hours, and centrifuged, washed, and dried after the reaction to obtain the metal organic framework material NU-1008.

2. The preparation method according to claim 1, characterized in that: The concentration of the Lewis acid metal ion is 0.1-0.2M.

3. Use of a heterogeneous catalyst prepared by the preparation method according to any one of claims 1 to 2 in catalyzing the isomerization of glucose into fructose.

4. The use according to claim 3, characterized in that: Specifically, the method comprises the following steps: adding a heterogeneous catalyst to a heated glucose solution, filling with N2 and exhausting the air, reacting at 70-100°C, filtering after the reaction to obtain a solid and a filtrate, adding deionized water of an equal volume to the filtrate to carry out a hydrolysis reaction; wherein the mass ratio of the heterogeneous catalyst to the glucose in the glucose solution is (5-15):

40.

5. The use according to claim 4, characterized in that: The solvent of the glucose solution is ethanol or n-propanol.

6. The use according to claim 4, characterized in that: The hydrolysis reaction time is 24h and the hydrolysis temperature is 90°C.

7. The use according to claim 4, characterized in that: The reaction time is 8-12h.

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