Highly selective magnesium-based solid base catalysts for aldehyde ketonization reactions and applications thereof

Abstract

The present application belongs to the field of supported solid base catalysts, and particularly relates to a high-selectivity magnesium-based solid base catalyst for aldehyde sugar ketonization reaction and application thereof. The method of the present application is as follows: taking alkali metal-doped magnesium-based oxide with a co-continuous macroporous and mesoporous structure having a uniform pore size distribution as a catalyst, specifically dispersing and dissolving a niobium phosphate oxide carrier, a magnesium precursor, an alkali metal (lithium, sodium or potassium) precursor and a surface spreading agent in deionized water, stirring at room temperature, evaporating the solvent to dryness, placing the obtained solid in a high-temperature furnace for calcination at 500-800 DEG C, and obtaining a supported alkali metal-doped magnesium-based oxide solid base. The catalyst prepared by the present application has high reaction selectivity, and a product with high content of rare ketose is obtained under mild conditions.

Description

Technical Field

[0001] This invention belongs to the field of supported solid base catalysts, and particularly relates to a supported solid base catalyst for aldose ketylation reaction and its application. Background Technology

[0002] Sugars in nature typically exist as aldoses or their polymers, such as glucose, cellulose, starch, xylose, arabinose, ribose, hemicellulose, lactose, and melibiose. In the catalytic reaction steps that convert aldoses into small-molecule organic acids, polyols, and other chemicals, the efficiency of the conversion of aldoses to ketoses (ketolation) affects the yield of the final product and the energy consumption of the entire process. However, due to the poor thermal stability of ketoses, numerous side reactions during preparation, and the lack of efficient catalysts, the final yield and raw material utilization of rare ketoses are limited. To date, the efficient preparation of rare ketoses remains unresolved.

[0003] The enzymatic method for preparing ketoses by aldose-ketylation has disadvantages such as high cost, limited reaction temperature range, long reaction time, irreversible inactivation, and high substrate specificity. This means that different enzyme preparations are often required to prepare different rare ketoses, and enzymes for certain aldose-ketylating processes, such as meldylose, have not yet been obtained. Compared to enzymatic methods, chemical methods have advantages such as high substrate universality, wide operating temperature range, and relatively simple catalyst preparation processes, and therefore have attracted much attention.

[0004] Homogeneous basic catalysis primarily utilizes alkali metal / alkaline earth metal hydroxides or organolithic basic compounds as catalysts, a method with over 100 years of history. However, since its inception, it has faced numerous challenges in terms of reaction mechanisms and cost, including rapid side reactions, numerous byproducts, difficulty in increasing substrate concentration (<1%), low efficiency, low ketose yield, high catalyst dosage (up to 200%), poor selectivity, difficulty in catalyst separation, and limited product applications. Similarly, Lewis acid catalysis in aqueous phases is limited by issues related to substrate selectivity, product separation and purification, and the applications of ketose products. Sn-beta zeolite, as a solid Lewis acid catalyst, can catalyze the conversion of aldoses to ketoses, such as glucose to fructose and xylose to xylulose. However, Sn-beta zeolite lacks substrate universality; for example, its catalytic activity towards arabinose is relatively weak. Furthermore, the substrate is hydrolyzed during the isomerization of disaccharides or polysaccharides, leading to a decrease in reaction selectivity. Additionally, heavy metal ions (Sn) may leak, causing heavy metal contamination of the product.

[0005] Magnesium oxide (MgO) possesses basicity due to the presence of unsaturated coordinated oxygen ions on its surface, thus it can act as a solid base to catalyze aldose-ketylation reactions. Pure MgO exhibits low selectivity in aldose-ketylation reactions, which can be mitigated by loading it to alter its surface atomic structure and chemical properties. Loading MgO onto Na-Y zeolite can improve reaction selectivity and product yield; however, this reaction system requires a nitrogen atmosphere and a large catalyst dosage, resulting in low productivity—that is, a low amount of ketose produced per unit weight of catalyst per unit time. Previously, the inventors discovered that loading MgO with hierarchical porous niobium oxyphosphate can improve the catalytic activity and aqueous phase stability of MgO (CN202210016933.4), increasing the productivity of the catalytic system by nearly four times compared to MgO supported on Na-Y zeolite; however, the reaction selectivity of this catalyst is only about 65%. Therefore, how to further improve the selectivity of aldose-ketylation reactions is the problem this invention aims to solve. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a highly selective alkali metal-doped magnesium-based solid base catalyst for aldose ketylation reactions and its application. Using alkali metal-doped magnesium oxide supported on niobium oxyphosphate with a co-continuous macroporous and mesoporous structure of uniform pore size distribution as a solid base catalyst, a series of aldoses with the same structure or disaccharides containing reducing aldose residues can be catalytically converted into the corresponding ketoses, significantly improving the selectivity of the aldose ketylation reaction.

[0007] To achieve the objectives of this invention, the specific technical solution adopted is as follows:

[0008] Magnesium precursors and alkali metal (lithium, sodium, or potassium) precursors are loaded onto NbP-X support material via impregnation, followed by drying and calcination activation to obtain a highly selective magnesium-based solid base catalyst for aldose ketylation reactions.

[0009] The present invention further provides a method for preparing a supported magnesium-based solid base catalyst, wherein a magnesium precursor, an alkali metal precursor and a surface spreading agent are dispersed and dissolved in deionized water with a niobium oxyphosphate (NbP-X) support material, and the mixture is stirred for 0.5 to 6 hours. The solvent is then evaporated until dry, and the resulting solid is ground into powder and placed in a high-temperature furnace for calcination and activation at 500 to 800°C for 2 to 10 hours to obtain a supported magnesium-based solid base catalyst.

[0010] Furthermore, the magnesium precursor and NbP-X carrier material are in a mass ratio of 0.6:1 to 4:1, and the lithium, sodium or potassium and magnesium are in a molar ratio of 1:20 to 1:1.

[0011] Furthermore, magnesium precursors include magnesium nitrate; alkali metal precursors include alkali metal carbonates.

[0012] Furthermore, the roasting atmosphere can be air or oxygen-helium.

[0013] Furthermore, the surface developing agent is a liquid organic acid; specifically, it can be a liquid organic acid such as lactic acid, pyruvic acid, acetic acid, and propionic acid; lactic acid is more preferred. The molar ratio of the surface developing agent to magnesium ions is 0.5:1 to 2:1.

[0014] Furthermore, the preparation method of NbP-X carrier material includes the following steps: α-hydroxy acid chelation coupled with sol-gel phase separation, followed by drying, to synthesize a non-stoichiometric amorphous niobium oxide-phosphoric acid-organic compound (abbreviated as niobium oxyphosphate) dry gel material. This dry gel material, after calcination at 300–600 °C, yields a specific surface area of ​​100–180 m². 2 The carrier material is denoted as NbP-X, where X is the calcination temperature.

[0015] Specifically, α-hydroxy acid and niobium ammonium oxalate chelate powder is dispersed in 35 wt.% hydrogen peroxide at 70–90 °C for 6–18 hours for digestion. After cooling the solution, polyethylene glycol and polyacrylamide solutions are added and stirred until dissolved and clear. Concentrated phosphoric acid is added to gel the solution and separate the phases, yielding a niobium oxide-phosphoric acid-organic gel material. This niobium oxide-phosphoric acid-organic gel material is then calcined at 300–600 °C for 6–12 hours to obtain NbP-X support materials with or without carbon components.

[0016] To ensure a good three-dimensional co-continuous macroporous structure of the carrier material, this invention further specifies that the polymer is polyethylene glycol and polyacrylamide, with polyethylene glycol used at 12-25 g / mol of niobium ammonium oxalate and polyacrylamide used at 90-130 g / mol of niobium ammonium oxalate; wherein, the α-hydroxy acid can be citric acid or lactic acid; and the molar ratio of α-hydroxy acid to niobium ammonium oxalate is 1:1.

[0017] The application of the above-mentioned solid base catalyst in the aldose ketylation reaction includes the following steps: dissolving and dispersing the supported solid base catalyst and the reactant aldose in deionized water, reacting at 100℃~150℃ for 10 minutes~120 minutes, centrifuging to separate the supported solid base catalyst, and then using an ion exchange resin (preferably hydrogen form) A 120 ion exchange resin is used to remove residual magnesium and alkali metal ions (lithium, sodium, potassium) from the solution, followed by concentration and purification to obtain high-purity aldose-ketylated products. The mass ratio of the supported solid base catalyst to the reactant sugar is 1:1 to 1:50.

[0018] The present invention further lists that the reactant sugar can be any one of the following reducing sugars or disaccharides with aldose residues at the reducing end: glucose, galactose, xylose, ribose, arabinose, cellobiose, maltose, isomaltose, lactose, melibiose, etc.

[0019] Effects of the Invention: The beneficial effects of using the technical solution of this invention include: the niobium phosphate-supported alkali metal-doped magnesium oxide solid base catalyst synthesized by this invention maintains the original co-continuous macroporous structure of the support material, which is beneficial to the diffusion of sugar molecules during the reaction; after being supported by niobium phosphate, the bond length between magnesium ions and oxygen ions in the magnesium oxide crystal increases, thereby making the oxygen on the crystal surface more basic, which plays a role in catalyzing the isomerization of aldoses to ketoses; the doped alkali metal ions enter the interior of the magnesium oxide lattice and the solid surface, increasing the number and density of catalytic sites, and at the same time reducing the activity of side reaction sites through electron donation, inhibiting the degradation of reactant aldoses and product ketoses. Finally, a highly reactive supported magnesium-based oxide solid base catalyst was prepared, yielding a product with a high content of rare ketoses under mild conditions. Attached Figure Description

[0020] Figure 1 Transmission electron microscopy (TEM) image of a 10% Na-MgO / NbP solid base catalyst. Detailed Implementation

[0021] This invention is not limited to the specific embodiments listed below. Those skilled in the art can implement this invention using various other specific embodiments based on the content disclosed herein. Any modifications or alterations made to the design structure and concept of this invention are also within the scope of protection of this invention. It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0022] The present invention will be further described in detail below with reference to the embodiments:

[0023] Example 1 Synthesis of supported lithium-doped magnesium-based oxide solid base: 5% Li-MgO x / NbP

[0024] 1 mol of ammonium niobate oxalate hydrate and 1 mol of citric acid were dissolved and dispersed in 225 ml of 35% hydrogen peroxide solution. After digestion and dissolution at 80°C, the solution was cooled to room temperature. 20 g of polyethylene glycol (molecular weight 35,000) and 100 g of polyacrylamide solution (molecular weight 10,000, mass concentration 50%) were added. After thorough mixing, 140 ml of concentrated phosphoric acid (mass concentration >83%) was added. The resulting white solid was exchanged with methanol and n-hexane solvents and dried under vacuum to obtain niobium oxyphosphate xenogel. The obtained niobium oxyphosphate xenogel was calcined in a high-temperature furnace at 600°C for 8 hours. The resulting white solid was used as a lithium-doped magnesium oxide carrier NbP-600.

[0025] 10g of the niobium phosphate support NbP-600 was dispersed and dissolved in 200ml of deionized water with 25.6g of magnesium nitrate hexahydrate, 0.183g of lithium carbonate, and 8.94g of lactic acid. The mixture was stirred at room temperature for 12 hours, and the solvent was evaporated until dry. The resulting solid was calcined in a high-temperature furnace at 700℃ for 5 hours to obtain a pure white solid. This solid was ground into powder to obtain a supported lithium-doped magnesium-based oxide solid alkali 5% Li-MgO with a magnesium oxide to niobium phosphate mass ratio of 0.4:1 and a lithium to magnesium molar ratio of 0.05:1. x / NbP.

[0026] Example 2 Synthesis of supported lithium-doped magnesium-based oxide solid base: 10% Li-MgO x / NbP

[0027] Compared with Example 1, the difference is that 10g of the niobium phosphate support NbP-600 was dispersed and dissolved in 200ml of deionized water with 25.6g of magnesium nitrate hexahydrate, 0.367g of lithium carbonate, and 8.94g of lactic acid; that is, the molar ratio of lithium to magnesium was 0.1:1. Other operations were the same as in Example 1, to prepare a supported lithium-doped magnesium-based oxide solid base 10% Li-MgO. x / NbP.

[0028] Example 3 Synthesis of supported lithium-doped magnesium-based oxide solid base: 15% Li-MgO x / NbP

[0029] Compared with Example 1, the difference is that 10g of the niobium phosphate support was dispersed and dissolved in 200ml of deionized water along with 25.6g of magnesium nitrate hexahydrate, 0.550g of lithium carbonate, and 8.94g of lactic acid; that is, the molar ratio of lithium to magnesium was 0.15:1. Other operations were the same as in Example 1, yielding a supported lithium-doped magnesium-based oxide solid alkali, 15% Li-MgO. x / NbP.

[0030] Example 4 Synthesis of supported lithium-doped magnesium-based oxide solid base: 20% Li-MgO x / NbP

[0031] Compared with Example 1, the difference is that 10g of the niobium phosphate support was dispersed and dissolved in 200ml of deionized water along with 25.6g of magnesium nitrate hexahydrate, 0.733g of lithium carbonate, and 8.94g of lactic acid; that is, the molar ratio of lithium to magnesium was 0.2:1. Other operations were the same as in Example 1, yielding a supported lithium-doped magnesium-based oxide solid alkali, 20% Li-MgO. x / NbP.

[0032] Example 5 Synthesis of supported sodium-doped magnesium-based oxide solid base: 5% Na-MgO x / NbP

[0033] 10g of the niobium oxyphosphate support was dispersed and dissolved in 200ml of deionized water with 25.6g of magnesium nitrate hexahydrate, 0.263g of sodium carbonate, and 8.94g of lactic acid. The mixture was stirred at room temperature for 12 hours, and the solvent was evaporated until dry. The resulting solid was calcined in a high-temperature furnace at 700℃ for 5 hours to obtain a pure white solid. This solid was ground into powder to obtain a supported sodium-doped magnesium-based oxide solid alkali 5% Na-MgO with a magnesium oxide to niobium oxyphosphate mass ratio of 0.4:1 and a sodium to magnesium molar ratio of 0.05:1. x / NbP.

[0034] Example 6 Synthesis of supported sodium-doped magnesium-based oxide solid base: 10% Na-MgO x / NbP

[0035] Compared with Example 5, the difference is that 10g of the niobium phosphate support was dispersed and dissolved in 200ml of deionized water with 25.6g of magnesium nitrate hexahydrate, 0.526g of sodium carbonate, and 8.94g of lactic acid; that is, the molar ratio of sodium to magnesium was 0.1:1. Other operations were the same as in Example 5, to prepare a supported sodium-doped magnesium-based oxide solid alkali 10% Na-MgO. x / NbP.

[0036] Example 7 Synthesis of supported sodium-doped magnesium-based oxide solid base: 15% Na-MgO x / NbP

[0037] Compared with Example 5, the difference is that 10g of the niobium phosphate support was dispersed and dissolved in 200ml of deionized water with 25.6g of magnesium nitrate hexahydrate, 0.789g of sodium carbonate, and 8.94g of lactic acid; that is, the molar ratio of sodium to magnesium was 0.15:1. Other operations were the same as in Example 5, and a supported sodium-doped magnesium-based oxide solid alkali 15% Na-MgO was prepared. x / NbP.

[0038] Example 8 Synthesis of supported sodium-doped magnesium-based oxide solid base: 20% Na-MgO x / NbP

[0039] Compared with Example 5, the difference is that 10g of the niobium phosphate support was dispersed and dissolved in 200ml of deionized water along with 25.6g of magnesium nitrate hexahydrate, 1.052g of sodium carbonate, and 8.94g of lactic acid; that is, the molar ratio of sodium to magnesium was 0.2:1. Other operations were the same as in Example 5, yielding a supported sodium-doped magnesium-based oxide solid alkali 20% Na-MgO. x / NbP.

[0040] Example 9 Synthesis of supported sodium-doped magnesium-based oxide solid base: 25% Na-MgO x / NbP

[0041] Compared with Example 5, the difference is that 10g of the niobium phosphate support was dispersed and dissolved in 200ml of deionized water with 25.6g of magnesium nitrate hexahydrate, 1.315g of sodium carbonate, and 8.94g of lactic acid; that is, the molar ratio of sodium to magnesium was 0.25:1. Other operations were the same as in Example 5, to prepare a supported sodium-doped magnesium-based oxide solid alkali 25% Na-MgO. x / NbP.

[0042] Example 10 Synthesis of supported sodium-doped magnesium-based oxide solid base: 30% Na-MgO x / NbP

[0043] Compared with Example 5, the difference is that 10g of the niobium phosphate support was dispersed and dissolved in 200ml of deionized water with 25.6g of magnesium nitrate hexahydrate, 1.578g of sodium carbonate, and 8.94g of lactic acid; that is, the molar ratio of sodium to magnesium was 0.3:1. Other operations were the same as in Example 5, to prepare a supported sodium-doped magnesium-based oxide solid alkali 30% Na-MgO. x / NbP.

[0044] Example 11 Synthesis of supported potassium-doped magnesium-based oxide solid base: 5% K-MgO x / NbP

[0045] 10g of the niobium oxyphosphate support was dispersed and dissolved in 200ml of deionized water with 25.6g of magnesium nitrate hexahydrate, 0.343g of potassium carbonate, and 8.94g of lactic acid. The mixture was stirred at room temperature for 12 hours, and the solvent was evaporated until dry. The resulting solid was calcined in a high-temperature furnace at 700℃ for 5 hours to obtain a pure white solid. This solid was ground into powder, which was then identified as a supported potassium-doped magnesium-based oxide solid alkali 5% K-MgO with a magnesium oxide to niobium oxyphosphate mass ratio of 0.4:1 and a potassium to magnesium molar ratio of 0.05:1. x / NbP.

[0046] Example 12 Synthesis of supported potassium-doped magnesium-based oxide solid base: 10% K-MgO x / NbP

[0047] Compared with Example 11, the difference is that 10g of the niobium phosphate support was dispersed and dissolved in 200ml of deionized water with 25.6g of magnesium nitrate hexahydrate, 0.686g of potassium carbonate, and 8.94g of lactic acid, i.e., the molar ratio of potassium to magnesium was 0.1:1. Other operations were the same as in Example 11, to prepare a supported potassium-doped magnesium-based oxide solid base 10% K-MgO. x / NbP.

[0048] Example 13 Synthesis of supported potassium-doped magnesium-based oxide solid base: 15% K-MgOx / NbP

[0049] Compared with Example 11, the difference is that 10g of the niobium phosphate support was dispersed and dissolved in 200ml of deionized water with 25.6g of magnesium nitrate hexahydrate, 1.029g of potassium carbonate and 8.94g of lactic acid, i.e., the molar ratio of potassium to magnesium was 0.15:1. Other operations were the same as in Example 11, to prepare a supported potassium-doped magnesium-based oxide solid base 15% K-MgO. x / NbP.

[0050] Example 14 Synthesis of supported potassium-doped magnesium-based oxide solid base: 20% K-MgO x / NbP

[0051] Compared with Example 11, the difference is that 10g of the niobium phosphate support was dispersed and dissolved in 200ml of deionized water with 25.6g of magnesium nitrate hexahydrate, 1.371g of potassium carbonate, and 8.94g of lactic acid, i.e., the molar ratio of potassium to magnesium was 0.2:1. Other operations were the same as in Example 11, yielding a supported potassium-doped magnesium-based oxide solid alkali 20% K-MgO. x / NbP.

[0052] Example 15 Synthesis of supported potassium-doped magnesium-based oxide solid base: 25% K-MgO x / NbP

[0053] Compared with Example 11, the difference is that 10g of the niobium phosphate support was dispersed and dissolved in 200ml of deionized water with 25.6g of magnesium nitrate hexahydrate, 1.714g of potassium carbonate and 8.94g of lactic acid, i.e., the molar ratio of potassium to magnesium was 0.25:1. Other operations were the same as in Example 11, to prepare a supported potassium-doped magnesium-based oxide solid base 25% K-MgO. x / NbP.

[0054] Example 16 Synthesis of supported potassium-doped magnesium-based oxide solid base: 30% K-MgO x / NbP

[0055] Compared with Example 11, the difference is that 10g of the niobium phosphate support was dispersed and dissolved in 200ml of deionized water with 25.6g of magnesium nitrate hexahydrate, 2.057g of potassium carbonate, and 8.94g of lactic acid, i.e., the molar ratio of potassium to magnesium was 0.3:1. Other operations were the same as in Example 11, yielding a supported potassium-doped magnesium-based oxide solid alkali 30% K-MgO. x / NbP.

[0056] Comparative Example 1: Synthesis of magnesium oxide solid base: MgO x / NbP

[0057] Compared to Example 1, lithium carbonate and lactic acid were not added, but all other operations were the same, resulting in the preparation of a supported magnesium oxide solid alkali MgO with a magnesium oxide to niobium oxyphosphate mass ratio of 0.4:1. x / NbP; The preparation method is the same as that in Example 2 of CN202210016933.4.

[0058] Comparative Example 2: Commercially available magnesium oxide as a catalyst

[0059] Application 1:

[0060] Dissolve 1g of glucose in 100ml of deionized water, add 1g of the catalyst prepared in Examples 1-16 and Comparative Examples 1-2, and stir the reaction at 120℃ for 30 minutes, then cool to room temperature. Centrifuge the reaction solution at 10000r / min to remove the solid catalyst. Add 30g of hydrogen form to the resulting solution. Residual magnesium and alkali metal (lithium, sodium, or potassium) ions in the solution were removed using ion exchange resin 120. The solution was then concentrated and purified (the generated ketoses were identified based on the peak times of each sugar in liquid chromatography analysis. High-purity ketose products were obtained through separation and purification using preparative or analytical columns), yielding fructose. The yield and selectivity of fructose were measured; details are shown in Table 1.

[0061] Table 1

[0062]

[0063]

[0064] Based on Application 1, the effect of glucose dosage on selection rate was studied. Other conditions were the same as in Application 1. See Table 2 for details.

[0065] Table 2

[0066]

[0067] Based on Application 1, the effect of reaction temperature on selectivity was studied. Other conditions were the same as in Application 1. See Table 3 for details.

[0068] Table 3

[0069]

[0070] Application 2:

[0071] 1 g of cellobiose was dissolved in 100 ml of deionized water, and 1 g of the catalyst prepared in Examples 1-16 and Comparative Examples 1-2 was added. The mixture was stirred at 130 °C for 60 minutes, and then cooled to room temperature. The reaction solution was centrifuged at 10000 r / min to remove the solid catalyst. 30 g of the hydrogen form was added to the resulting solution. 120 ion exchange resin removes residual magnesium ions and alkali metal (lithium, sodium, or potassium) ions from the solution. Further concentration, separation, and purification yield a high-purity cellodiulose product. The yield and selectivity of cellodiulose were tested; details are shown in Table 4.

[0072] Table 4

[0073] Example catalyst Fibrodiol yield Cholesterol selectivity Example 1 <![CDATA[5%Li-MgO x / NbP]]> 25.7％ 60.4％ Example 2 <![CDATA[10%Li-MgO x / NbP]]> 27.3％ 61.5％ Example 3 <![CDATA[15%Li-MgO x / NbP]]> 26.5％ 59.8％ Example 4 <![CDATA[20%Li-MgO x / NbP]]> 26.8％ 60.4％ Example 5 <![CDATA[5%Na-MgO x / NbP]]> 30.5％ 76.5％ Example 6 <![CDATA[10%Na-MgO x / NbP]]> 41.0％ 89.7％ Example 7 <![CDATA[15%Na-MgO x / NbP]]> 38.4％ 78.3％ Example 8 <![CDATA[20%Na-MgO x / NbP]]> 39.6％ 80.2％ Example 9 <![CDATA[25%Na-MgO x / NbP]]> 35.0％ 79.8％ Example 10 <![CDATA[30%Na-MgO x / NbP]]> 35.9％ 78.9％ Example 11 <![CDATA[5%K-MgO x / NbP]]> 32.3％ 65.6％ Example 12 <![CDATA[10%K-MgO x / NbP]]> 32.8％ 66.8％ Example 13 <![CDATA[15%K-MgO x / NbP]]> 34.2％ 68.0％ Example 14 <![CDATA[20%K-MgO x / NbP]]> 33.6％ 65.0％ Example 15 <![CDATA[25%K-MgO x / NbP]]> 33.0％ 66.1％ Example 16 <![CDATA[30%K-MgO x / NbP]]> 34.1％ 64.4％ Comparative Example 1 <![CDATA[MgO x / NbP]]> 26.9％ 51.1％ Comparative Example 2 Commercially available magnesium oxide 20.4％ 32.0％

[0074] Compared with Application 2, this study investigated the effect of cellobiose dosage on the selection rate, with other conditions remaining the same as in Application 2. See Table 5 for details.

[0075] Table 5

[0076]

[0077] Application 3

[0078] Dissolve 1g of lactose in 100ml of deionized water, add 1g of the catalyst prepared in Examples 1-16 and Comparative Examples 1-2, and stir the reaction at 110℃ for 60 minutes, then cool to room temperature. Centrifuge the reaction solution at 10000r / min to remove the solid catalyst. Add 30g of the hydrogen form to the resulting solution. 120 ion exchange resin was used to remove residual magnesium ions and alkali metal (lithium, sodium, or potassium) ions from the solution. Further concentration, separation, and purification yielded a high-purity lactulose product. The yield and selectivity of lactulose were measured; details are shown in Table 6.

[0079] Table 6

[0080] Example catalyst lactulose yield lactulose selectivity Example 1 <![CDATA[5%Li-MgO x / NbP]]> 26.3％ 65.0％ Example 2 <![CDATA[10%Li-MgO x / NbP]]> 28.4％ 70.1％ Example 3 <![CDATA[15%Li-MgO x / NbP]]> 27.9％ 70.2％ Example 4 <![CDATA[20%Li-MgO x / NbP]]> 27.5％ 69.5％ Example 5 <![CDATA[5%Na-MgO x / NbP]]> 28.8％ 78.6％ Example 6 <![CDATA[10%Na-MgO x / NbP]]> 29.8％ 83.7％ Example 7 <![CDATA[15%Na-MgO x / NbP]]> 28.4％ 80.5％ Example 8 <![CDATA[20%Na-MgO x / NbP]]> 28.5％ 79.8％ Example 9 <![CDATA[25%Na-MgO x / NbP]]> 29.0％ 79.5％ Example 10 <![CDATA[30%Na-MgO x / NbP]]> 28.3％ 79.7％ Example 11 <![CDATA[5%K-MgO x / NbP]]> 24.6％ 65.8％ Example 12 <![CDATA[10%K-MgO x / NbP]]> 28.8％ 70.5％ Example 13 <![CDATA[15%K-MgO x / NbP]]> 28.5％ 71.4％ Example 14 <![CDATA[20%K-MgO x / NbP]]> 27.9％ 74.3％ Example 15 <![CDATA[25%K-MgO x / NbP]]> 28.0％ 73.2％ Example 16 <![CDATA[30%K-MgO x / NbP]]> 27.8％ 75.8％ Comparative Example 1 <![CDATA[MgO x / NbP]]> 29.3％ 66.2％ Comparative Example 2 Commercially available magnesium oxide 21.1％ 53.6％

[0081] Compared with Application 3, this study investigated the effect of lactose dosage on the selection rate, with other conditions remaining the same as in Application 3. See Table 7 for details.

[0082] Table 7

[0083]

[0084] Application 4

[0085] Dissolve 1g of melibiose in 100ml of deionized water, add 1g of the catalyst prepared in Examples 1-16 and Comparative Examples 1-2, and stir the reaction at 110℃ for 50 minutes, then cool to room temperature. Centrifuge the reaction solution at 10000r / min to remove the solid catalyst. Add 30g of the hydrogen form to the resulting solution. 120 ion exchange resin was used to remove residual magnesium ions and alkali metal (lithium, sodium, or potassium) ions from the solution. Further concentration, separation, and purification yielded a high-purity meliodyne product. The yield and selectivity of meliodyne were measured; details are shown in Table 8.

[0086] Table 8

[0087] Example catalyst Yield of melidiol Selectivity of melidiol Example 1 <![CDATA[5%Li-MgO x / NbP]]> 21.4％ 58.8％ Example 2 <![CDATA[10%Li-MgO x / NbP]]> 22.4％ 69.5％ Example 3 <![CDATA[15%Li-MgO x / NbP]]> 23.8％ 68.9％ Example 4 <![CDATA[20%Li-MgO x / NbP]]> 22.9％ 68.8％ Example 5 <![CDATA[5%Na-MgO x / NbP]]> 23.2％ 75.0％ Example 6 <![CDATA[10%Na-MgO x / NbP]]> 23.6％ 77.9％ Example 7 <![CDATA[15%Na-MgO x / NbP]]> 22.5％ 75.6％ Example 8 <![CDATA[20%Na-MgO x / NbP]]> 23.0％ 75.2％ Example 9 <![CDATA[25%Na-MgO x / NbP]]> 22.7％ 70.4％ Example 10 <![CDATA[30%Na-MgO x / NbP]]> 20.6％ 71.3％ Example 11 <![CDATA[5%K-MgO x / NbP]]> 19.4％ 63.4％ Example 12 <![CDATA[10%K-MgO x / NbP]]> 20.5％ 65.6％ Example 13 <![CDATA[15%K-MgO x / NbP]]> 20.2％ 63.3％ Example 14 <![CDATA[20%K-MgO x / NbP]]> 19.8％ 66.7％ Example 15 <![CDATA[25%K-MgO x / NbP]]> 18.7％ 67.3％ Example 16 <![CDATA[30%K-MgO x / NbP]]> 19.3％ 65.8％ Comparative Example 1 <![CDATA[MgO x / NbP]]> 23.7％ 60.6％ Comparative Example 2 Commercially available magnesium oxide 17.6％ 47.8％

[0088] Compared with Application 4, this study investigated the effect of melibiose dosage on the selection rate, with other conditions remaining the same as in Application 4. See Table 9 for details.

[0089] Table 9

[0090]

[0091] Application 5

[0092] Dissolve 1g of maltose in 100ml of deionized water, add 1g of the catalyst prepared in Examples 1-16 and Comparative Examples 1-2, and stir the reaction at 110℃ for 60 minutes, then cool to room temperature. Centrifuge the reaction solution at 10000r / min to remove the solid catalyst. Add 30g of the hydrogen form to the resulting solution. Residual magnesium and alkali metal (lithium, sodium, or potassium) ions in the solution were removed using ion exchange resin 120. The solution was then concentrated, separated, and purified to obtain a high-purity maltulose product. The yield and selectivity of maltulose were determined; details are shown in Table 10.

[0093] Table 10

[0094] Example catalyst maltose yield maltose selectivity Example 1 <![CDATA[5%Li-MgO x / NbP]]> 28.3％ 59.8％ Example 2 <![CDATA[10%Li-MgO x / NbP]]> 30.7％ 60.2％ Example 3 <![CDATA[15%Li-MgO x / NbP]]> 29.4％ 58.2％ Example 4 <![CDATA[20%Li-MgO x / NbP]]> 30.8％ 57.9％ Example 5 <![CDATA[5%Na-MgO x / NbP]]> 30.1％ 66.3％ Example 6 <![CDATA[10%Na-MgO x / NbP]]> 31.0％ 66.4％ Example 7 <![CDATA[15%Na-MgO x / NbP]]> 30.5％ 64.7％ Example 8 <![CDATA[20%Na-MgO x / NbP]]> 29.6％ 63.1％ Example 9 <![CDATA[25%Na-MgO x / NbP]]> 30.2％ 65.1％ Example 10 <![CDATA[30%Na-MgO x / NbP]]> 29.3％ 63.6％ Example 11 <![CDATA[5%K-MgO x / NbP]]> 28.7％ 58.5％ Example 12 <![CDATA[10%K-MgO x / NbP]]> 29.2％ 58.4％ Example 13 <![CDATA[15%K-MgO x / NbP]]> 27.8％ 56.9％ Example 14 <![CDATA[20%K-MgO x / NbP]]> 30.0％ 59.3％ Example 15 <![CDATA[25%K-MgO x / NbP]]> 30.5％ 52.6％ Example 16 <![CDATA[30%K-MgO x / NbP]]> 29.5％ 52.9％ Comparative Example 1 <![CDATA[MgO x / NbP]]> 30.4％ 51.5％ Comparative Example 2 Commercially available magnesium oxide 15.3％ 33.5％

[0095] Compared with Application 5, this study investigated the effect of maltose dosage on the selection rate, with other conditions remaining the same as in Application 5. See Table 11 for details.

[0096] Table 11

[0097]

[0098] Application 6

[0099] Dissolve 1g of isomaltose in 100ml of deionized water, add 1g of the catalyst prepared in Examples 1-16 and Comparative Examples 1-2, and stir the reaction at 110℃ for 60 minutes, then cool to room temperature. Centrifuge the reaction solution at 10000r / min to remove the solid catalyst. Add 30g of the hydrogen form to the resulting solution. Residual magnesium and alkali metal (lithium, sodium, or potassium) ions in the solution were removed using ion exchange resin 120. The solution was then concentrated, separated, and purified to obtain a high-purity isomaltulose product. The yield and selectivity of isomaltulose were determined; details are shown in Table 12.

[0100] Table 12

[0101]

[0102]

[0103] Compared with Application 6, this study investigated the effect of isomaltose dosage on the selection rate, with other conditions remaining the same as in Application 6. See Table 13 for details.

[0104] Table 13

[0105]

[0106] Application 7

[0107] 1 g of ribose was dissolved in 100 ml of deionized water, and 1 g of the catalyst prepared in Examples 1-16 and Comparative Examples 1-2 was added. The mixture was stirred at 120 °C for 40 minutes, and then cooled to room temperature. The reaction solution was centrifuged at 10000 r / min to remove the solid catalyst. 30 g of hydrogen form was added to the resulting solution. Residual magnesium and alkali metal (lithium, sodium, or potassium) ions in the solution were removed using ion exchange resin 120. The solution was then concentrated, separated, and purified to obtain a high-purity ribulose product. The yield and selectivity of ribulose were measured; details are shown in Table 14.

[0108] Table 14

[0109]

[0110]

[0111] Compared with Application 7, this study investigated the effect of ribose dosage on the selectivity, with other conditions remaining the same as in Application 7. See Table 15 for details.

[0112] Table 15

[0113]

[0114] Application 8

[0115] Dissolve 1g of xylose in 100ml of deionized water, add 1g of the catalyst prepared in Examples 1-16 and Comparative Examples 1-2, and stir the reaction at 120℃ for 40 minutes, then cool to room temperature. Centrifuge the reaction solution at 10000r / min to remove the solid catalyst. Add 30g of the hydrogen form of the catalyst to the resulting solution. Residual magnesium and alkali metal (lithium, sodium, or potassium) ions in the solution were removed using ion exchange resin 120. The solution was then concentrated, separated, and purified to obtain a high-purity xylulose product. The yield and selectivity of xylulose were determined; details are shown in Table 16.

[0116] Table 16

[0117]

[0118]

[0119] Compared with Application 8, this study investigated the effect of xylose dosage on the selection rate, with other conditions remaining the same as in Application 8. See Table 17 for details.

[0120] Table 17

[0121]

[0122] Application 9

[0123] Dissolve 1g of galactose in 100ml of deionized water, add 1g of the catalyst prepared in Examples 1-16 and Comparative Examples 1-2, and stir the reaction at 120℃ for 40 minutes, then cool to room temperature. Centrifuge the reaction solution at 10000r / min to remove the solid catalyst. Add 30g of the hydrogen form to the resulting solution. Residual magnesium and alkali metal (lithium, sodium, or potassium) ions in the solution were removed using ion exchange resin 120. The solution was then concentrated, separated, and purified to obtain a high-purity tagatose product. The yield and selectivity of the tagatose were determined; details are shown in Table 18.

[0124] Table 18

[0125] Example catalyst Tagar yield Tagar selection rate Example 1 <![CDATA[5%Li-MgO x / NbP]]> 14.8％ 49.0％ Example 2 <![CDATA[10%Li-MgO x / NbP]]> 15.3％ 57.1％ Example 3 <![CDATA[15%Li-MgO x / NbP]]> 14.4％ 55.7％ Example 4 <![CDATA[20%Li-MgO x / NbP]]> 14.9％ 56.4％ Example 5 <![CDATA[5%Na-MgO x / NbP]]> 15.0％ 57.8％ Example 6 <![CDATA[10%Na-MgO x / NbP]]> 15.6％ 59.9％ Example 7 <![CDATA[15%Na-MgO x / NbP]]> 15.1％ 56.1％ Example 8 <![CDATA[20%Na-MgO x / NbP]]> 14.8％ 55.8％ Example 9 <![CDATA[25%Na-MgO x / NbP]]> 15.4％ 55.4％ Example 10 <![CDATA[30%Na-MgO x / NbP]]> 14.5％ 56.9％ Example 11 <![CDATA[5%K-MgO x / NbP]]> 14.1％ 57.0％ Example 12 <![CDATA[10%K-MgO x / NbP]]> 15.1％ 57.1％ Example 13 <![CDATA[15%K-MgO x / NbP]]> 14.9％ 53.6％ Example 14 <![CDATA[20%K-MgO x / NbP]]> 14.7％ 55.1％ Example 15 <![CDATA[25%K-MgO x / NbP]]> 15.1％ 56.3％ Example 16 <![CDATA[30%K-MgO x / NbP]]> 15.2％ 50.8％ Comparative Example 1 <![CDATA[MgO x / NbP]]> 15.2％ 46.6％ Comparative Example 2 Commercially available magnesium oxide 11.7％ 34.6％

[0126] Compared with Application 9, this study investigated the effect of galactose dosage on the selection rate, with other conditions remaining the same as in Application 9. See Table 19 for details.

[0127] Table 19.

[0128]

[0129] Examples 17-19

[0130] Compared with Example 6, the difference is that lactic acid was replaced with pyruvic acid, acetic acid, and propionic acid respectively, while other operations were the same as in Example 6, resulting in supported sodium-doped magnesium-based oxide solid bases (10% Na-MgO) prepared with different surface spreading agents. x / NbP.

[0131] Comparative Example 3

[0132] Compared with Example 6, the difference is that lactic acid was not added, but all other operations were the same as in Example 6 to prepare a supported sodium-doped magnesium-based oxide solid base 10% Na-MgO. x / NbP.

[0133] The application is the same as application 1, and the results are detailed in Table 20.

[0134] Table 20

[0135]

[0136] The results showed that in the fructose reaction of glucose preparation, 5%–30% Na-MgO x / NbP compared to MgO x / NbP exhibits higher selectivity. In the lactose-to-lactose reaction, 10%–20% Li-MgO x / NbP, 5%–30% Na-MgO x / NbP, 10%–30% K-MgO x / NbP compared to MgO x / NbP exhibits higher selectivity. In the reaction for preparing melidiols from melibiose, 10%–20% Li-MgO x / NbP, 5%–30% Na-MgO x / NbP, 5%–30% K-MgO x / NbP compared to MgO x / NbP has a higher selectivity.

[0137] In the aldose-ketylation reactions of cellobiose, maltose, isomaltose, ribose, xylose, and galactose, 5%–20% Li-MgO x / NbP, 5%–30% Na-MgO x / NbP, 5%–30% K-MgO x / NbP compared to MgO x / NbP has a higher selectivity.

Claims

1. A magnesium-based solid base catalyst for the ketonization of an aldehyde, characterized in that: The preparation method of the catalyst is as follows: dispersing, dissolving a magnesium precursor, an alkali metal precursor and a surface unfolding agent in deionized water in a niobium oxyphosphate carrier material, stirring for a certain time, drying and calcining to obtain a niobium oxyphosphate supported alkali metal doped magnesium-based oxide solid base catalyst for aldo-sugar ketonization reaction; wherein the alkali metal is one or several of lithium, sodium or potassium; The molar ratio of the alkali metal to magnesium is 1:20-1:1; the molar ratio of the surface unfolding agent to magnesium is 0.5:1-2:1; the surface unfolding agent is a liquid organic acid, and the liquid organic acid is lactic acid, pyruvic acid, acetic acid or propionic acid; The phosphorus-oxygen niobium carrier is prepared by the following steps: α - hydroxy acid and ammonium niobium oxalate powder are dispersed in hydrogen peroxide at 70-90°C to digest and dissolve, polyethylene glycol and polyacrylamide solution are added after the solution is cooled and stirred until dissolved and clear, concentrated phosphoric acid is added to gel the solution, a gel material is obtained after drying, and the gel material is calcined at 300-600°C for 6-12 hours to obtain the phosphorus-oxygen niobium carrier; wherein α - the hydroxy acid is citric acid or lactic acid; α - the molar ratio of the hydroxy acid to ammonium niobium oxalate is 1:

1.

2. The magnesium-based solid base catalyst for the ketonization of aldehyde sugars according to claim 1, characterized by: The calcination condition is calcination activation at 500-800 DEG C for 2-10 hours; the calcination atmosphere can be air or oxygen-helium.

3. The magnesium-based solid base catalyst for the ketonization of aldehyde sugars according to claim 1, characterized by: The surface unfolding agent is lactic acid.

4. Use of the magnesium-based solid base catalyst according to any one of claims 1 to 3 in the ketonization of an aldose, characterized in that: The magnesium-based solid base catalyst and the reactant sugar are dissolved and dispersed in deionized water according to a mass ratio, and reacted at 100-150 DEG C; the catalyst is separated by centrifugation after the reaction, the magnesium and alkali metal ions remaining in the solution are removed by ion exchange resin, and the aldo-sugar ketonization product is obtained by concentration and refining.

5. Use of the magnesium-based solid base catalyst according to claim 4 in the aldose ketonization reaction, characterized by: The reactant sugar is one of glucose, galactose, xylose, ribose, arabinose, cellobiose, maltose, isomaltose, lactose and melibiose.

6. Use of the magnesium-based solid base catalyst according to claim 4 in the aldolization reaction of an aldehyde, characterized in that: The mass ratio of the solid base catalyst to the reactant sugar is 1:1-1:50.

Images