Yttrium oxide catalyst, preparation method and application thereof, and method for preparing lactic acid from glucose

Abstract

The invention relates to the technical field of supported catalysts and the technical field of preparation of lactic acid through glucose catalysis, in particular to an yttrium oxide catalyst, a preparation method and application of the yttrium oxide catalyst and a method for preparing lactic acid through glucose, a carrier of the yttrium oxide catalyst is graphene, and an active component is yttrium oxide; wherein the graphene is sulfonated graphene oxide; the percentage content of yttrium oxide in the yttrium oxide catalyst is 10-50%. The yttrium oxide catalyst prepared by the invention can realize high-efficiency conversion from glucose to lactic acid under the condition of no additional alkali, and is more environment-friendly compared with the existing solid catalyst and liquid-phase strong alkali catalyst for preparing lactic acid by catalyzing glucose, and the preparation method is also simple and easy to operate, is suitable for large-scale production, and has a wide application prospect. And meanwhile, better application and popularization are facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of supported catalysts and the technical field of preparing lactic acid by catalysis of glucose, and in particular to an yttrium oxide catalyst and a preparation method and application thereof, and a method for preparing lactic acid by using glucose. Background Art

[0002] Lactic acid is one of the three most important organic acids recognized by the world. It can be used as an important synthetic intermediate platform and is widely used in the daily chemical industry, pharmaceutical industry, chemical industry, surface material industry and other fields, with extremely high application value. In addition, lactic acid can also be used to prepare polylactic acid, which can effectively solve the pollution problem caused by global plastics. At present, the market demand for lactic acid is increasing, and the study of the synthesis of lactic acid is of great application value.

[0003] Glucose is the most abundant monosaccharide in nature. It can be widely derived from corn, cellulose and starch. It is cheap and has a wide range of applications. The catalytic production of lactic acid using glucose as a raw material has attracted much attention.

[0004] Liquid strong bases show good catalytic performance in catalyzing the production of lactic acid from glucose. The literature (Molecular Catalysis, 2021, 502: 111406) uses Ca(OH)2 and other liquid bases such as Ba(OH)2, Mg(OH)2 or Sr(OH)2 to catalyze the synthesis of lactic acid from glucose. The reaction temperature is 60°C and the reaction time is 12 hours. The better conversion of glucose can be achieved, and the catalytic performance obtained by the synergistic catalysis of Ca(OH)2 and Ba(OH)2 is the best, and the lactic acid yield can reach more than 40%. It is worth noting that the process route of glucose catalysis with liquid strong base has many reaction by-products, mainly including fructose, glyceric acid, glycolic acid, acetic acid and formic acid. At the same time, the reaction process is relatively demanding, requiring a large amount of liquid base, and is prone to side reactions with sugar or products. In addition, these hot bases are very corrosive to the reaction equipment, which limits its industrial production.

[0005] At present, some supported catalysts have been tried for the reaction of glucose catalysis to produce lactic acid. For example, beta molecular sieves are loaded with Y or Yb catalysts, and the yield of lactic acid has been improved to a certain extent. The literature (ACS Omega 2022, 7: 25200-25209) prepared a series of Y-β and Yb-β catalysts by solid-state ion exchange method. After catalyzing glucose at 190°C for 2 hours, the maximum yield of lactic acid can reach 45.3% and 43.6%, respectively. This fully demonstrates that the performance of solid catalysts is comparable to that of liquid-phase strong base catalysts to a certain extent, and can better achieve the selective conversion of glucose to lactic acid. The selection, preparation and green feasibility of the catalyst production process still need to be improved. Summary of the invention

[0006] The purpose of the present invention is to provide an yttrium oxide catalyst and a preparation method and application thereof, and a method for preparing lactic acid from glucose in view of the problems existing in the reaction of using supported catalysts to catalyze the production of lactic acid from glucose. The yttrium oxide catalyst prepared by the present invention can realize the efficient conversion of glucose into lactic acid without the addition of an alkali, is more environmentally friendly than the existing solid catalyst and liquid-phase strong base catalyst used for catalyzing the production of lactic acid from glucose, and the preparation method is simple and easy to operate, suitable for mass production, and is conducive to better application and promotion.

[0007] In order to achieve the above-mentioned object, in a first aspect, the present invention provides a yttrium oxide catalyst, wherein the carrier of the yttrium oxide catalyst is graphene and the active component is yttrium oxide; wherein:

[0008] The graphene is sulfonated graphene oxide;

[0009] The percentage of yttrium oxide in the yttrium oxide catalyst is 10-50%.

[0010] In a second aspect, the present invention provides a method for preparing a yttrium oxide catalyst, the preparation method comprising: mixing sulfonated graphene oxide and yttrium salt in the presence of a solvent, impregnating, drying to obtain a catalyst precursor, and then calcining the catalyst precursor.

[0011] Preferably, the yttrium salt is selected from one or two or more of yttrium nitrate, yttrium halide, yttrium acetate and yttrium organic alkoxide.

[0012] Preferably, the yttrium salt is selected from one or two or more of yttrium nitrate, yttrium fluoride, yttrium chloride, yttrium bromide, yttrium acetate and yttrium isopropoxide.

[0013] More preferably, the solvent is selected from one or two or more of water, methanol and ethanol.

[0014] Preferably, the mass ratio of the sulfonated graphene oxide to the yttrium salt is 1:0.34-1.7, wherein the mass of the yttrium salt is calculated based on the mass of yttrium oxide.

[0015] Preferably, the mixing conditions include: ultrasonic time of 0.5-2h, stirring time of 5-12h, and stirring rate of 300-1000rpm.

[0016] Preferably, the immersion conditions include: temperature of 15-30°C and time of 6-12h.

[0017] More preferably, the drying conditions include: a temperature of 100-120° C. and a time of 12-24 hours.

[0018] Further preferably, the calcination conditions include: temperature of 300-600° C., time of 2-4 h, and heating rate of 1-20° C. / min.

[0019] Preferably, the method for preparing sulfonated graphene oxide comprises: first mixing NaOH solution, sulfonation reagent and nitrite, second mixing by adding coolant and concentrated hydrochloric acid, third mixing by adding graphene oxide, washing and vacuum drying.

[0020] Preferably, the sulfonating agent is selected from one or two or more of p-aminobenzenesulfonic acid, sulfonic acid, benzenesulfonic acid, aminosulfonic acid and isethionic acid.

[0021] More preferably, the nitrite is sodium nitrite and / or potassium nitrite.

[0022] Further preferably, the coolant is selected from one or two or more of an ice-water mixture, an ethylene glycol-water mixture and a glycerol-water mixture.

[0023] Preferably, the mass ratio of the NaOH solution, the sulfonating agent and the nitrite is 1:3-10:2-10

[0024] Preferably, the concentrated hydrochloric acid accounts for 5-20% of the total solution volume.

[0025] Further preferably, the second mixing conditions include: stirring time of 1-3 h, stirring rate of 300-1000 rpm.

[0026] Further preferably, the conditions of the third mixing include: stirring time of 3-6 hours, stirring rate of 500-1000 rpm.

[0027] Further preferably, the washing conditions include: washing with detergent 3-4 times.

[0028] More preferably, the detergent is ethanol and / or methanol.

[0029] Further preferably, the vacuum drying conditions include: temperature of 30-80° C. and time of 6-24 h.

[0030] In a third aspect, the present invention provides an yttrium oxide catalyst prepared by the preparation method described in the second aspect.

[0031] In a fourth aspect, the present invention provides a use of the yttrium oxide catalyst described in the first aspect or the third aspect in catalyzing the production of lactic acid from glucose.

[0032] In a fifth aspect, the present invention provides a method for preparing lactic acid from glucose, the method comprising: placing an yttrium oxide catalyst and glucose in a high-pressure reactor in the presence of a solvent and an inert gas to carry out a catalytic reaction, wherein:

[0033] The yttrium oxide catalyst is the yttrium oxide catalyst described in claim 1 or claim 8.

[0034] Preferably, the weight ratio of the yttrium oxide catalyst to glucose is 1:1-30.

[0035] More preferably, the conditions of the catalytic reaction include: temperature of 150-240° C. and time of 1-10 h.

[0036] More preferably, the solvent is water.

[0037] More preferably, the inert gas is nitrogen and / or argon.

[0038] In the above technical solution, the present invention prepares yttrium oxide catalyst by surface modification of graphene and coupling with metal yttrium oxide. 2 The hexagonal two-dimensional carbon material with a single atomic layer thickness composed of hybrid orbitals has excellent physical, chemical, mechanical and electronic properties. The yttrium oxide catalyst of the present invention utilizes the large specific surface area of ​​graphene oxide to provide planar support and special properties for metal yttrium oxide to regulate the interaction between its yttrium oxide active component and the graphene oxide carrier, and then sulfonates the graphene oxide to adjust the surface acid groups of the graphene oxide, enhance the interaction between it and the active component yttrium oxide, regulate the surface structure and acid-base center of the yttrium oxide catalyst of the present invention, and at the same time increase the hydrophilicity of the yttrium oxide catalyst, promote the dispersion of the catalyst in the aqueous medium, thereby improving the accessibility to glucose molecules and significantly improving its ability to catalyze the conversion of glucose.

[0039] On the other hand, the yttrium oxide catalyst of the present invention is prepared by an impregnation method, and the active component exists in the form of an oxide, and does not require high-temperature hydrogen reduction treatment, so the operation is simple.

[0040] At the same time, the yttrium oxide catalyst of the present invention does not need to add additional alkaline reagents in the catalytic reaction system for catalytic cracking of glucose to produce lactic acid, which is beneficial to environmental protection and sustainable production. It has excellent performance in catalyzing glucose to produce lactic acid, and the yield of lactic acid can reach 48.2%, which has broad application prospects.

[0041] Other features and advantages of the present invention will be described in detail in the following detailed description. DETAILED DESCRIPTION

[0042] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0043] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0044] In a first aspect, the present invention provides a yttrium oxide catalyst, wherein the carrier of the yttrium oxide catalyst is graphene and the active component is yttrium oxide; wherein:

[0045] The graphene is sulfonated graphene oxide;

[0046] The percentage of yttrium oxide in the yttrium oxide catalyst is 10-50%.

[0047] The present invention prepares yttrium oxide catalyst by surface modification of graphene and coupling with metal yttrium oxide. 2 The hexagonal two-dimensional carbon material with a single atomic layer thickness composed of hybrid orbitals has excellent physical, chemical, mechanical and electronic properties. The yttrium oxide catalyst of the present invention utilizes the large specific surface area of ​​graphene oxide to provide planar support and special properties for metal yttrium oxide to regulate the interaction between its yttrium oxide active component and the graphene oxide carrier, and then sulfonates the graphene oxide to adjust the surface acid groups of the graphene oxide, enhance the interaction between it and the active component yttrium oxide, regulate the surface structure and acid-base center of the yttrium oxide catalyst of the present invention, and at the same time increase the hydrophilicity of the yttrium oxide catalyst, promote the dispersion of the catalyst in the aqueous medium, thereby improving the accessibility to glucose molecules and significantly improving its ability to catalyze the conversion of glucose.

[0048] In a second aspect, the present invention provides a method for preparing an yttrium oxide catalyst, the preparation method comprising:

[0049] In the presence of a solvent, sulfonated graphene oxide and yttrium salt are mixed, impregnated, and dried to obtain a catalyst precursor, and then the catalyst precursor is calcined.

[0050] The yttrium oxide catalyst of the present invention is prepared by an impregnation method, and the active component exists in the form of oxides, and high-temperature hydrogen reduction treatment is not required, so the operation is simple.

[0051] In a preferred embodiment of the present invention, in order to regulate the formation of yttrium oxide and its efficient loading on the carrier surface, the yttrium salt is selected from one or two or more of yttrium nitrate, yttrium halide, yttrium acetate and yttrium organic alkoxide.

[0052] In a preferred embodiment of the present invention, in order to regulate the formation of yttrium oxide and its efficient loading on the carrier surface, the yttrium salt is selected from one or two or more of yttrium nitrate, yttrium fluoride, yttrium chloride, yttrium bromide, yttrium acetate and yttrium isopropoxide.

[0053] In a preferred embodiment of the present invention, in order to fully dissolve the yttrium salt and ensure the dispersion characteristics of the active component on the carrier surface, the solvent is selected from one or two or more of water, methanol and ethanol, wherein water can be distilled water, deionized water or ultrapure water; one or two or more of water, methanol and ethanol can also be mixed in any proportion as a solvent.

[0054] In a preferred embodiment of the present invention, in order to regulate the adsorption and dispersion, molding and interaction between the catalyst active components on the carrier surface and the carrier, the mass ratio of the sulfonated graphene oxide and the yttrium salt is 1:0.34-1.7, wherein the mass of the yttrium salt is calculated based on the mass of yttrium oxide.

[0055] In a preferred embodiment of the present invention, in order to promote the full dispersion of the active components on the surface of the carrier, the mixing conditions include: ultrasonic time of 0.5-2h, stirring time of 5-12h, and stirring rate of 300-1000rpm.

[0056] In a preferred embodiment of the present invention, in order to regulate the interaction between the active component and the carrier base, the impregnation conditions include: a temperature of 15-30° C. and a time of 6-12 h.

[0057] In a preferred embodiment of the present invention, in order to promote the adsorption and interaction of active components on the surface of the carrier, the drying conditions include: a temperature of 100-120° C. and a drying time of 12-24 h.

[0058] In a preferred embodiment of the present invention, in order to ensure sufficient thermal decomposition of the yttrium salt and its effective generation on the carrier surface, the calcination conditions include: temperature of 300-600°C, time of 2-4h, and heating rate of 1-20°C / min.

[0059] In a preferred embodiment of the present invention, in order to ensure complete sulfonation of graphene oxide, the method for preparing sulfonated graphene oxide includes: first mixing NaOH solution, sulfonation reagent and nitrite, adding coolant and concentrated hydrochloric acid for second mixing, then adding graphene oxide for third mixing, washing, and vacuum drying.

[0060] In a preferred embodiment of the present invention, in order to ensure the smooth progress of the sulfonation process and the degree of sulfonation, the sulfonating agent is selected from one or two or more of p-aminobenzenesulfonic acid, sulfonic acid, benzenesulfonic acid, aminosulfonic acid and isethionic acid.

[0061] In a preferred embodiment of the present invention, in order to promote the formation of diazonium salt during the sulfonation process, the nitrite is sodium nitrite and / or potassium nitrite.

[0062] In a preferred embodiment of the present invention, in order to ensure the low temperature requirement during the sulfonation process, the coolant is selected from one or two or more of an ice-water mixture, an ethylene glycol-water mixture and a glycerol-water mixture.

[0063] In a preferred embodiment of the present invention, in order to complete the sulfonation process, the mass ratio of the NaOH solution, the sulfonation reagent and the nitrite is 1:3-10:2-10.

[0064] In a preferred embodiment of the present invention, in order to adjust the structure and surface characteristics of graphene, the concentrated hydrochloric acid accounts for 5-20% of the total solution volume.

[0065] In a preferred embodiment of the present invention, in order to promote the mixing effect and prevent local agglomeration during the process, the second mixing conditions include: a stirring time of 1-3 hours and a stirring rate of 300-1000 rpm.

[0066] In a preferred embodiment of the present invention, in order to control the degree of mixing, the conditions of the third mixing include: a stirring time of 3-6 hours and a stirring rate of 500-1000 rpm.

[0067] In a preferred embodiment of the present invention, in order to filter out impurities generated during the process, the washing conditions include: washing with a detergent for 3-4 times.

[0068] In a preferred embodiment of the present invention, in order to filter out organic impurities, the detergent is ethanol and / or methanol.

[0069] In a preferred embodiment of the present invention, in order to ensure the structural integrity of the sulfonated graphene oxide and to ensure that the surface groups are not destroyed, the vacuum drying conditions include: a temperature of 30-80° C. and a time of 6-24 h.

[0070] In a third aspect, the present invention provides an yttrium oxide catalyst prepared by the preparation method described in the second aspect.

[0071] In a fourth aspect, the present invention provides a use of the yttrium oxide catalyst described in the first aspect or the third aspect in catalyzing the production of lactic acid from glucose.

[0072] In a fifth aspect, the present invention provides a method for preparing lactic acid from glucose, the method comprising: placing an yttrium oxide catalyst and glucose in a high-pressure reactor in the presence of a solvent and an inert gas to carry out a catalytic reaction, wherein:

[0073] The yttrium oxide catalyst is the yttrium oxide catalyst described in the first aspect or the third aspect.

[0074] The yttrium oxide catalyst of the present invention does not need to add additional alkaline reagents in the catalytic reaction system for catalytically cracking glucose to produce lactic acid, is beneficial to environmental protection and sustainable production, has excellent performance in catalyzing glucose to produce lactic acid, and the yield of lactic acid can reach 48.2%, which has broad application prospects.

[0075] In a preferred embodiment of the present invention, in order to adjust the degree of mutual contact between the active component and the reactant molecules, the weight ratio of the yttrium oxide catalyst to glucose is 1:1-30.

[0076] In a preferred embodiment of the present invention, in order to ensure that the reaction proceeds in the direction of generating lactic acid, the conditions of the catalytic reaction include: a temperature of 150-240° C. and a time of 1-10 h.

[0077] In a preferred embodiment of the present invention, the solvent is water, which may be deionized water, ultrapure water or distilled water.

[0078] In a preferred embodiment of the present invention, the inert gas is nitrogen and / or argon.

[0079] In a preferred embodiment of the present invention, room temperature refers to a temperature of 15-30°C.

[0080] In a preferred embodiment of the present invention, concentrated hydrochloric acid refers to a hydrogen chloride aqueous solution with a mass fraction of hydrogen chloride of 36% to 38%.

[0081] The present invention will be described in detail below by way of examples. In the following examples, the drugs and medicaments are all conventional commercial products.

[0082] Preparation Example 1

[0083] Prepare 20 mL of 2% NaOH solution, add 2 g of p-aminobenzenesulfonic acid and 0.8 g of sodium nitrite to fully dissolve, add ice cubes to control the reaction temperature at 0°C, add 4 mL of concentrated hydrochloric acid, stir for 3 hours, then add 2 g of graphene oxide (GO) with a mass concentration of 10 mg / mL, stir for 6 hours, wash with ethanol three times, and vacuum dry at 40°C for 12 hours to obtain sulfonated graphene oxide (SGO), which is recorded as A1.

[0084] Preparation Example 2

[0085] The method of Preparation Example 1 was followed, except that "p-aminobenzenesulfonic acid" was replaced by "aminosulfonic acid" and other conditions remained unchanged, to obtain sulfonated graphene oxide (SGO), which was recorded as A2.

[0086] Example 1

[0087] (1) 1 g of sulfonated graphene oxide (SGO) A1 prepared in Preparation Example 1 and 0.5 g of yttrium nitrate hexahydrate were weighed and dissolved in 10 mL of deionized water at room temperature, ultrasonically treated for 0.5 h, stirred for 6 h, and then immersed for 6 h, placed in an oven, and dried at 110 ° C. for 24 h to obtain a catalyst precursor;

[0088] (2) The obtained catalyst precursor was placed in a muffle furnace, the heating rate was controlled at 5°C / min, the temperature was raised to 500°C, calcined for 2h, and cooled to room temperature to obtain an yttrium oxide catalyst (Y2O3 / SGO) with a yttrium oxide loading of 15%, which was recorded as Cat 1.

[0089] Example 2

[0090] The method of Example 1 was followed, except that in step (1), "sulfonated graphene oxide (SGO) A1 obtained in Preparation Example 1" was replaced by "sulfonated graphene oxide (SGO) A2 obtained in Preparation Example 2", and other conditions remained unchanged to obtain the corresponding Y2O3 / SGO, which was recorded as Cat 2.

[0091] Example 3

[0092] The method of Example 1 was followed, except that in step (1), "0.5 g of yttrium nitrate hexahydrate" was replaced by "0.3 g of yttrium isopropoxide" and other conditions remained unchanged to obtain the corresponding Y2O3 / SGO, which was recorded as Cat 3.

[0093] Example 4

[0094] The method of Example 1 was followed, except that in step (1), "0.5 g of yttrium nitrate hexahydrate" was replaced by "0.67 g of yttrium nitrate hexahydrate" and other conditions remained unchanged to obtain the corresponding Y2O3 / SGO, which was recorded as Cat 4.

[0095] Example 5

[0096] The method of Example 1 was followed, except that in step (2), "raising the temperature to 500° C." was replaced by "raising the temperature to 350° C.", and other conditions remained unchanged, to obtain the corresponding Y2O3 / SGO, which was recorded as Cat 5.

[0097] Comparative Example 1

[0098] The method of Example 1 was followed, except that "sulfonated graphene oxide (SGO) A1 obtained in Preparation Example 1" in step (1) was replaced by "graphene oxide (GO)", and other conditions remained unchanged, to obtain the corresponding Y2O3 / GO, which was recorded as Cat A.

[0099] Comparative Example 2

[0100] The method of Example 1 was followed, except that 0.5 g of yttrium nitrate hexahydrate was not added in step (1), and other conditions remained unchanged, to obtain a catalyst without yttrium oxide loading, which was recorded as CatB.

[0101] Comparative Example 3

[0102] The method of Example 1 was followed, except that the "sulfonated graphene oxide (SGO) A1 obtained in Preparation Example 1" in step (1) was replaced by "reduced graphene oxide (GO)", and other conditions remained unchanged, to obtain the corresponding yttrium oxide catalyst, denoted as Cat C.

[0103] Application Example 1

[0104] The performance evaluation test of the catalytic glucose production of lactic acid reaction of the present invention is carried out in a high-pressure reactor, and the specific steps are as follows:

[0105] 0.2 g of yttrium oxide catalyst Cat 1 obtained in Example 1, 0.2 g of glucose, and 20 mL of deionized water were weighed and put into a high-pressure reactor. The air in the reactor was replaced with nitrogen and the pressure was maintained at 1.0 MPa. The reaction temperature was controlled at 220°C. The mixture was heated and stirred for 1 h. After cooling to room temperature, the filtrate was collected and the product was analyzed by high performance liquid chromatography (HPLC).

[0106] The above catalyst Cat 1 was replaced by Cat 2-5 and Cat AC respectively, and the other steps and conditions were the same.

[0107] The catalytic performance is shown in Table 1.

[0108] Table 1 Performance of glucose in producing lactic acid under different catalysts

[0109]

[0110] It can be seen from the above and Table 1 that the yield of lactic acid in the reaction of catalyzing glucose to produce lactic acid by the yttrium oxide catalysts prepared in Examples 1-5 of the present invention is as high as 48.2%.

[0111] At the same time, Comparative Example 1 also uses an yttrium oxide catalyst prepared by the impregnation method, but the carrier is graphene oxide that has not been sulfonated. In the reaction of catalyzing glucose to produce lactic acid, the glucose conversion rate is only 55.6%, and the lactic acid yield is 11.7%. In the reaction of catalyzing glucose to produce lactic acid, the yttrium oxide catalyst prepared by the preparation method of the present invention has a glucose conversion rate of at least 90.7% and a lactic acid yield of at least 38.2%, which are both much higher than the catalytic performance of the catalyst prepared in Comparative Example 1, indicating that the yttrium oxide catalyst prepared by the preparation method of the present invention has significantly better catalytic performance than the yttrium oxide catalyst prepared in Comparative Example 1.

[0112] In addition, in Comparative Example 2, the catalyst Cat B without yttrium salt loading was prepared. Although the glucose conversion rate was 81.2% in the reaction of catalyzing glucose to produce lactic acid, the lactic acid yield was only 7.8%. It can be seen that the catalytic performance of Cat B without loading the active component yttrium oxide is very low; further, although the yttrium oxide catalyst Cat C prepared in Comparative Example 3 loaded the active component yttrium oxide, the carrier was reduced graphene oxide. In the reaction of catalyzing glucose to produce lactic acid, the glucose conversion rate was 91.2%, but the lactic acid yield was only 4.1%, and the catalytic performance was also very poor, indicating that it is difficult to convert glucose into lactic acid by simply selecting a carrier or an active component. The yttrium oxide catalyst of the present invention uses yttrium oxide as the active component and is loaded on sulfonated graphene oxide. The combination of the two exerts the best catalytic performance in the reaction of catalyzing glucose to produce lactic acid.

[0113] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0114] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0115] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A yttrium oxide catalyst, characterized in that The carrier of the yttrium oxide catalyst is graphene, and the active component is yttrium oxide; wherein, The graphene is sulfonated graphene oxide; The percentage of yttrium oxide in the yttrium oxide catalyst is 10-50%.

2. A method for preparing an yttrium oxide catalyst, characterized in that: The preparation method comprises: In the presence of a solvent, sulfonated graphene oxide and yttrium salt are mixed, impregnated, and dried to obtain a catalyst precursor, and then the catalyst precursor is calcined.

3. The preparation method according to claim 2, characterized in that: The yttrium salt is selected from one or two or more of yttrium nitrate, yttrium halide, yttrium acetate and yttrium organic alkoxide; Preferably, the yttrium salt is selected from one or two or more of yttrium nitrate, yttrium fluoride, yttrium chloride, yttrium bromide, yttrium acetate and yttrium isopropoxide; More preferably, the solvent is selected from one or two or more of water, methanol and ethanol.

4. The preparation method according to claim 2 or 3, characterized in that: The mass ratio of the sulfonated graphene oxide to the yttrium salt is 1:0.34-1.7, wherein the mass of the yttrium salt is calculated based on the mass of yttrium oxide.

5. The preparation method according to any one of claims 2 to 4, characterized in that: The mixing conditions include: ultrasonic time of 0.5-2h, stirring time of 5-12h, and stirring rate of 300-1000rpm; Preferably, the immersion conditions include: temperature of 15-30°C, time of 6-12h; More preferably, the drying conditions include: temperature of 100-120°C and time of 12-24h; Further preferably, the calcination conditions include: temperature of 300-600° C., time of 2-4 h, and heating rate of 1-20° C. / min.

6. The preparation method according to any one of claims 2 to 5, characterized in that: The preparation method of sulfonated graphene oxide comprises: first mixing NaOH solution, sulfonation reagent and nitrite, second mixing by adding coolant and concentrated hydrochloric acid, third mixing by adding graphene oxide, washing and vacuum drying; Preferably, the sulfonating agent is selected from one or two or more of p-aminobenzenesulfonic acid, sulfonic acid, benzenesulfonic acid, aminosulfonic acid and isethionic acid; More preferably, the nitrite is sodium nitrite and / or potassium nitrite; Further preferably, the coolant is selected from one or two or more of an ice-water mixture, an ethylene glycol-water mixture and a glycerol-water mixture.

7. The preparation method according to claim 6, characterized in that: The mass ratio of the NaOH solution, the sulfonating agent and the nitrite is 1:3-10:2-10; Preferably, the concentrated hydrochloric acid accounts for 5-20% of the total solution volume; Further preferably, the second mixing conditions include: stirring time of 1-3h, stirring rate of 300-1000rpm; Further preferably, the conditions of the third mixing include: stirring time of 3-6h, stirring rate of 500-1000rpm; Further preferably, the washing conditions include: washing 3-4 times with a detergent; Further preferably, the detergent is ethanol and / or methanol; Further preferably, the vacuum drying conditions include: temperature of 30-80° C. and time of 6-24 h.

8. An yttrium oxide catalyst prepared according to the preparation method according to any one of claims 2 to 7.

9. Use of the yttrium oxide catalyst according to claim 1 or claim 8 in catalyzing the production of lactic acid from glucose.

10. A method for preparing lactic acid from glucose, characterized in that: The method comprises: In the presence of a solvent and an inert gas, a yttrium oxide catalyst and glucose are placed in a high-pressure reactor for catalytic reaction, wherein: The yttrium oxide catalyst is the yttrium oxide catalyst described in claim 1 or claim 8; Preferably, the weight ratio of the yttrium oxide catalyst to glucose is 1:1-30; More preferably, the conditions of the catalytic reaction include: temperature of 150-240°C and time of 1-10h; Further preferably, the solvent is water; More preferably, the inert gas is nitrogen and / or argon.

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