阅读说明：本技术 一种制备果糖的催化剂及其制备方法和应用 (Catalyst for preparing fructose and preparation method and application thereof ) 是由 张通 白毓黎 白富栋 李澜鹏 彭绍忠 乔凯 于 2019-10-31 设计创作，主要内容包括：本发明涉及一种制备果糖的催化剂及其制备方法和应用,采用水热处理制得改性Al-TUD-1/Y复合粒子,在该复合粒子上负载一定量Sn,得到Sn/Al-TUD-1/Y催化剂。本发明还提供了一种果糖制备方法,采用Sn/Al-TUD-1/Y催化剂制备果糖,对反应过程中生成的有色杂质具有良好的脱除效果,且具有果糖收率高、催化剂易分离回收和可重复利用等特点。(The invention relates to a catalyst for preparing fructose, a preparation method and application thereof, wherein modified Al-TUD-1/Y composite particles are prepared by adopting hydrothermal treatment, and a certain amount of Sn is loaded on the composite particles to obtain a Sn/Al-TUD-1/Y catalyst. The invention also provides a fructose preparation method, wherein the Sn/Al-TUD-1/Y catalyst is adopted to prepare fructose, the method has a good removal effect on colored impurities generated in the reaction process, and has the characteristics of high fructose yield, easy separation and recovery of the catalyst, reusability and the like.)

1. A preparation method of a catalyst for preparing fructose is characterized by comprising the following steps: (1) adding an aluminum source, a silicon source and a template agent for preparing Al-TUD-1 into a solvent to prepare a catalyst mother solution, then adding a Y-type molecular sieve, stirring and aging, carrying out hydrothermal treatment, and filtering, washing, drying and roasting a product to obtain Al-TUD-1/Y composite particles; (2) and (2) adding the composite particles obtained in the step (1) into a Sn precursor solution for reaction, and filtering, washing, drying and roasting after the reaction to obtain the Sn/Al-TUD-1/Y catalyst.

2. The method of claim 1, wherein: the aluminum source in the step (1) is at least one of aluminum isopropoxide, aluminum nitrate and aluminum chloride, and preferably aluminum isopropoxide; the silicon source is at least one of tetraethoxysilane and methyl orthosilicate, and preferably tetraethoxysilane; the template agent is at least one of diethylene glycol, triethylene glycol and tetraethylene glycol, preferably tetraethylene glycol; the solvent is mixed solution of isopropanol, ethanol and water or mixed solution of isopropanol, methanol and water, preferably mixed solution of isopropanol, ethanol and water.

3. The method of claim 2, wherein: the molar ratio of the components is aluminum source, silicon source, template agent, isopropanol, ethanol/methanol and water = (0.05-0.3), 1 (1-1.5), 5-10, 5-15 and 1-5.

4. The method of claim 1, wherein: the Y-type molecular sieve added in the step (1) is at least one of H-Y, Na-Y, H-USY and Na-USY, and preferably H-USY.

5. The method of claim 4, wherein: the silicon-aluminum ratio of the Y-type molecular sieve is 10-60, preferably 35-40; the particle size is 100nm to 100. mu.m, preferably 1 to 10 μm.

6. The method of claim 1, 4 or 5, wherein: the mass ratio of the addition amount of the Y-type molecular sieve to the silicon source in the catalyst mother liquor is 1 (2.5-35), and preferably 1 (5-14).

7. The method of claim 1, wherein: the aging time of the catalyst mother liquor in the step (1) is 5-10h, and the stirring speed is 100-; the temperature of the hydrothermal treatment is 150-180 ℃, preferably 155-165 ℃; the treatment time is 12-24h, preferably 16-18 h.

8. The method of claim 1, wherein: separating the product in the step (1) in a filtering or centrifuging mode, and washing the product for multiple times by using water; the drying temperature is 80-120 ℃, and the drying time is 5-20 h; the roasting temperature is 500-600 ℃, and the roasting time is 5-10 h.

9. The method of claim 1, wherein: in the Sn precursor solution in the step (2), the Sn source is at least one of stannic chloride, dimethyltin dichloride, dioctyltin, tetraphenyltin, tributyltin acetate and triphenyltin, and stannic chloride is preferred; the solvent is at least one of methanol, ethanol, acetone and toluene, preferably ethanol; the mass concentration of the Sn precursor solution is 1-20%.

10. The method according to claim 1 or 9, characterized in that: and (2) adding a small amount of piperine into the Sn precursor solution, wherein the adding amount is 0.5-5% of the mass of the solvent.

11. The method of claim 1, wherein: the mass ratio of the Al-TUD-1/Y composite particles to the Sn precursor solution in the step (2) is 1:5-100, preferably 1: 10-30.

12. The method of claim 1, wherein: and (2) reacting for 1-48h at the speed of 100-800r/min, separating products after the reaction in a filtering or centrifugal mode, wherein the washing solvent is the same as the solvent used by the Sn precursor solution.

13. The method of claim 1, wherein: the drying temperature in the step (2) is 100-120 ℃, and the drying time is 8-12 h; the roasting temperature is 500-600 ℃, and the roasting time is 4-5 h.

14. A catalyst for the production of fructose, characterized in that it is produced by a process according to any one of claims 1 to 13.

15. A process for the catalytic production of fructose using glucose, characterized in that it is produced using a catalyst according to claim 14.

16. The method of claim 15, wherein: adding glucose into alcohol solvent and/or water, adding catalyst to perform catalytic reaction, and separating out the catalyst after the reaction is finished to obtain a liquid-phase product containing fructose.

17. The method according to claim 15 or 16, characterized in that: the mass ratio of the catalyst to the glucose is 1:1-8, preferably 1: 2-5.

18. The method of claim 16, wherein: the ratio of glucose to the alcohol solvent and/or water is 1:5-100 (g: mL), preferably 1:10-30 (g: mL).

19. The method of claim 16, wherein: the alcohol solvent is at least one of methanol, ethanol, n-propanol, isopropanol and the like, and preferably methanol.

20. The method according to claim 15 or 16, characterized in that: the catalytic reaction temperature is 60-140 ℃, preferably 80-120 ℃; the reaction is carried out for 1-5h at 100-800 r/min.

Technical Field

The invention belongs to the field of fructose preparation, and particularly relates to a catalyst for preparing fructose, and a preparation method and application thereof.

Background

Fructose is used as an isomer of glucose, is a monosaccharide with the highest sweetness and the highest reaction activity in all natural sugars, is widely applied to the food, beverage and biochemical manufacturing industry, but has a small content and a high price in nature, so that the prospect of preparing fructose through low-cost glucose isomerization is very wide.

Currently, fructose is industrially produced by isomerizing glucose used as a raw material under the action of a biological enzyme to prepare fructose. However, the stability of the biological enzymes in the reaction process has a significant influence on the sugar conversion efficiency, the biological enzymes can survive in a certain acidic environment, the control on the reaction key parameters is very strict, and the production cost of the biological enzymes is very high, so that the fructose is limited to a certain extent in the synthesis process. In order to solve the technical problems in the process of preparing fructose by a biological enzyme method, a technology for preparing fructose by chemical catalytic isomerization of glucose becomes a research hotspot in recent years.

Patent CN106336437A discloses a method for preparing fructose by isomerizing glucose in a high-pressure closed environment in the presence of an acid catalyst and a lower alcohol, wherein the acid catalyst is selected from one or more of tungsten salt, aluminum salt, chromium salt, phosphotungstic acid and silicotungstic acid. The method has mild conditions, simple process, high conversion efficiency, and fructose yield of 21-39%. However, the problems of catalyst separation and recovery, equipment corrosion and the like exist, and colored impurities of the caramelization reaction cannot be effectively removed in the chemical catalysis process.

Patent CN106563495A discloses a glucose isomerization molecular sieve catalyst and a preparation method thereof. The preparation method comprises the following steps: (1) dealuminizing the prepared Al-Beta zeolite with acid to obtain high-silicon zeolite; (2) dissolving high-silicon zeolite and a tin source in organic alkali to form amorphous sol, and performing first hydrothermal crystallization to form Sn-Beta primary crystals; (3) and carrying out secondary hydrothermal crystallization, cooling, washing, drying and roasting on the Sn-Beta primary crystal with the aid of a mesoporous template to obtain the glucose isomerization molecular sieve catalyst. The prepared glucose isomerization molecular sieve catalyst is used for the isomerization reaction of glucose, the conversion rate of the glucose is 43.4-62.4%, and the yield of fructose is 22.3-47.6%. In the method, Beta zeolite needs dealumination to obtain high-silicon zeolite, the preparation process is complex, and colored impurities generated in the chemical catalysis process influence the quality of products.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a catalyst for preparing fructose, a preparation method and application thereof. The Sn/Al-TUD-1/Y catalyst provided by the invention is used for preparing fructose, has the characteristics of high fructose yield, easy separation and recovery of the catalyst, reusability and the like, and particularly has a good removing effect on colored impurities generated in the reaction process.

The preparation method of the catalyst for preparing fructose provided by the invention comprises the following steps:

(1) adding an aluminum source, a silicon source and a template agent for preparing Al-TUD-1 into a solvent to prepare a catalyst mother solution, then adding a Y-type molecular sieve, stirring and aging, carrying out hydrothermal treatment, and filtering, washing, drying and roasting a product to obtain Al-TUD-1/Y composite particles;

(2) and (2) adding the Al-TUD-1/Y composite particles obtained in the step (1) into a Sn precursor solution for reaction, and filtering, washing, drying and roasting after the reaction to obtain the Sn/Al-TUD-1/Y catalyst.

In the present invention, the aluminum source in the step (1) is at least one of aluminum isopropoxide, aluminum nitrate, aluminum chloride and the like, and aluminum isopropoxide is preferable. The silicon source is at least one of tetraethoxysilane, methyl orthosilicate and the like, and tetraethoxysilane is preferred. The template agent is at least one of diethylene glycol, triethylene glycol, tetraethylene glycol and the like, and preferably tetraethylene glycol. The solvent is mixed solution of isopropanol, ethanol and water or mixed solution of isopropanol, methanol and water, preferably mixed solution of isopropanol, ethanol and water, and the molar ratio of the isopropanol, the ethanol and the water is (2-3): (3-4): 1. The molar ratio of the components is aluminum source, silicon source, template agent, isopropanol, ethanol/methanol and water = (0.05-0.3), 1 (1-1.5), 5-10, 5-15 and 1-5.

In the invention, the Y-type molecular sieve added in the step (1) is at least one of H-Y, Na-Y, H-USY, Na-USY and the like, and H-USY is preferred. The silicon-aluminum ratio of the Y-type molecular sieve is 10-60, preferably 35-40; the particle size is 100nm to 100. mu.m, preferably 1 to 10 μm. The mass ratio of the addition amount of the Y-type molecular sieve to the silicon source in the catalyst mother liquor is 1 (2.5-35), and preferably 1 (5-14).

In the invention, the aging time of the catalyst mother liquor in the step (1) is 5-10h, and the stirring speed is 100-800 r/min. The temperature of the hydrothermal treatment is 150-180 ℃, preferably 155-165 ℃; the treatment time is 12-24h, preferably 16-18 h.

In the present invention, the product described in step (1) is separated by filtration, centrifugation or the like, and washed with water several times. The drying temperature is 80-120 ℃, and the drying time is 5-20 h; the roasting temperature is 500-600 ℃, and the roasting time is 5-10 h.

In the invention, in the Sn precursor solution in step (2), the Sn source is at least one of tin tetrachloride, tin dichloride, dimethyltin dichloride, dioctyltin, tetraphenyltin, tributyltin acetate, triphenyltin, etc., preferably tin tetrachloride; the solvent is at least one of methanol, ethanol, acetone, toluene, etc., preferably ethanol; the mass concentration of the Sn precursor solution is 1-20%. Furthermore, a small amount of piperine is added into the Sn precursor solution, and the adding amount is 0.05-1.0% of the mass of the solvent, so that the yield and the selectivity of fructose are further improved.

In the invention, the mass ratio of the Al-TUD-1/Y composite particles in the step (2) to the Sn precursor solution is 1:5-100, preferably 1: 10-30.

In the invention, the step (2) is reacted for 1-48h at the speed of 100-800r/min, products after the reaction are separated by the modes of filtration, centrifugation and the like, and the washing solvent is the same as the solvent used by the Sn precursor solution.

In the invention, the drying temperature in the step (2) is 100-120 ℃, and the drying time is 8-12 h; the roasting temperature is 500-600 ℃, and the roasting time is 4-5 h.

The catalyst for preparing the fructose is prepared by the method. The prepared catalyst is prepared by loading Sn on Al-TUD-1/Y composite particles, wherein the silicon-aluminum ratio of the Al-TUD-1/Y composite particles is 10-50, and the loading capacity of the Sn is 0.01-10% calculated by metal oxides.

The invention also provides a method for preparing fructose by catalyzing glucose, which adopts the catalyst for preparation. Adding glucose into alcohol solvent and/or water, adding the catalyst for catalytic reaction, and separating the catalyst after the reaction is finished to obtain a liquid-phase product containing fructose.

In the method for preparing fructose, the mass ratio of the catalyst to the glucose is 1:1-8, preferably 1: 2-5. The ratio of glucose to the alcohol solvent and/or water is 1:5-100 (g: mL), preferably 1:10-30 (g: mL). The alcohol solvent is at least one of methanol, ethanol, n-propanol, isopropanol and the like, and preferably methanol. The catalytic reaction temperature is 60-140 ℃, preferably 80-120 ℃; the reaction is carried out for 1-5h at 100-800 r/min.

Compared with the prior art, the invention has the following beneficial effects:

(1) the modified catalyst prepared by the invention has stronger removal function on colored byproducts generated in the reaction process, and saves the decolorization step in the subsequent fructose purification process.

(2) According to the invention, Al-TUD-1 is modified, namely a Y-type molecular sieve is added in the preparation process to obtain Al-TUD-1/Y composite particles, and then Sn is loaded to prepare the Sn/Al-TUD-1/Y catalyst.

Detailed Description

The technical solution and the technical effects of the present invention will be further described in detail with reference to the following examples. The embodiments are implemented on the premise of the technical scheme of the invention, and detailed implementation modes and specific operation processes are given, but the protection scope of the invention is not limited by the following embodiments.

The experimental procedures in the following examples are, unless otherwise specified, conventional in the art. The experimental materials used in the following examples were purchased from a conventional biochemical reagent store unless otherwise specified.

The content of glucose and fructose in the invention is detected by an Agilent 1260 type liquid chromatography analyzer, a chromatographic column is BIO-RAD HPX-87H, and the detection conditions are as follows: 5mM H₂SO₄The flow rate is 0.7mL/min, the column temperature is 65 ℃, and the temperature of the differential detector is 40 ℃. The chroma of the liquid phase product is detected by a platinum-cobalt colorimetric method.

Example 1

(1) Al-TUD-1/Y composite particles were prepared using the raw materials and ratios described in Table 1

TABLE 1 compounding of Al-TUD-1/Y composite particles

The substances in the table 1 are mixed according to the method in the step (1) of the invention, stirred and aged for 8h at room temperature and 300r/min, and the obtained colloid is subjected to hydrothermal treatment for 18h at 160 ℃. And filtering the product to separate the solid from the system, washing with water for 3 times, drying at 100 ℃ for 12h, and roasting at 600 ℃ for 6h to obtain the Al-TUD-1/Y composite particles.

(2) Adding 2g of the Al-TUD-1/Y composite particles obtained in the step (1) into 20g of 10% by mass stannic chloride ethanol solution, and reacting at normal temperature and 300r/min for 12 h. And filtering the product after the reaction to separate out a solid, washing the solid with ethanol for 3 times, drying the solid at 100 ℃ for 12 hours, and roasting the solid at 550 ℃ for 5 hours to obtain the Sn/Al-TUD-1/Y catalyst.

(3) And (3) adding 0.5g of Sn/Al-TUD-1/Y catalyst obtained in the step (2) and 2g of glucose into 30mL of methanol, reacting at 100 ℃ for 3h at 300r/min, cooling to room temperature after the reaction is finished, and filtering to separate out a solid catalyst to obtain a liquid-phase product containing fructose. The samples were subjected to liquid chromatography and colorimetric detection, and the results are shown in Table 2. The alcohol solvent in the filtrate can be recovered by reduced pressure distillation.

TABLE 2 reaction results of Sn/Al-TUD-1/Y catalysts obtained with different formulations

Example 2

(1) The procedure for synthesizing the Al-TUD-1/Y composite particles was the same as in example 1.

(2) The raw material ratios described in table 3 were used to carry out Sn loading on the composite particles.

TABLE 3 formulation of Sn loading in catalyst

Adding the Al-TUD-1/Y composite particles into the Sn precursor solution, and stirring and reacting for 12 hours at normal temperature and at the speed of 300 r/min; filtering to separate out solid, washing the solid with respective solvent for 3 times, drying at 100 deg.C for 12h, and calcining at 550 deg.C for 5h to obtain Sn/Al-TUD-1/Y catalyst.

(3) Adding 0.5g of the Sn/Al-TUD-1/Y catalyst obtained in the step (2) and 2g of glucose into 30mL of methanol, reacting for 3h at 100 ℃ at 300r/min, cooling to room temperature after the reaction is finished, and filtering to separate out a solid catalyst to obtain a liquid-phase product, wherein the results are shown in Table 4. The methanol in the filtrate can be recovered by distillation under reduced pressure.

TABLE 4 results of Sn/Al-TUD-1/Y catalyst reactions obtained with different formulations

Example 3

(1) And (2) Synthesis of Sn/Al-TUD-1/Y catalyst the same procedure as in example 1 was followed.

(3) And (3) adding 0.5g of the Sn/Al-TUD-1/Y catalyst A obtained in the step (2) and 2g of glucose into different solvents, reacting for 3 hours at 100 ℃ at 300r/min, cooling to room temperature after the reaction is finished, and filtering to separate out a solid catalyst to obtain a liquid-phase product, wherein the results are shown in Table 5. The alcohol solvent in the filtrate can be recovered by reduced pressure distillation.

TABLE 5 reaction results under different solvent conditions

Example 4

The solid catalyst A recovered in example 1 was calcined at 600 ℃ for 5 hours and then regenerated, and the catalyst was examined for recyclability, the reaction procedure was the same as in example 1, and the results are shown in Table 6.

TABLE 6 catalyst A recycle reaction results

Example 5

The other procedure was the same as in example 1 except that piperine was added to the Sn precursor solution in an amount of 0.5% by mass of the solvent during the preparation of the catalyst A, D, I in step (1), and the results are shown in table 7.

TABLE 7 results of the reaction after addition of piperine

Comparative example 1

The catalyst synthesis procedure was the same as for catalyst a of example 1, except that: the Y molecular sieve is not added in the preparation process of the catalyst, and the obtained catalyst is Sn/Al-TUD-1. The reaction results are shown in Table 8, and the reaction time is 3h, so the effect is improved, but the effect is still not as good as that of the catalyst of the invention.

Comparative example 2

Sn loading is carried out according to the step (2) of the embodiment 1 by directly adopting an H-USY molecular sieve with the silicon-aluminum ratio of 40 and the grain diameter of 2 mu m as a carrier, so as to prepare the Sn-USY catalyst, and the reaction result is shown in a table 8.

Comparative example 3

The catalyst synthesis procedure was the same as for catalyst a of example 1, except that: the synthesis mother liquor in the step (1) is not added with a Y molecular sieve to obtain Al-TUD-1, and then the Al-TUD-1 is physically mixed with an H-USY molecular sieve to be used as a carrier to prepare the catalyst by loading Sn according to the step (2) in the example 1, and the reaction results are shown in a table 8.

Comparative example 4

The composite particles A in example 1 were used as a reaction catalyst without Sn loading, and the reaction results are shown in Table 8.

TABLE 8 analysis results of reaction products in respective comparative examples