Application of a stable catalyst without activation in the oxidation of ethanol to acetaldehyde

Abstract

The application belongs to the technical field of industrial catalysis, and particularly relates to application of a catalyst without activation and with stable performance in preparation of acetaldehyde from ethanol oxidation. The ternary bulk catalyst with a composite oxide structure is filled in a tube of a shell-and-tube reactor, so that ethanol and oxygen nitrogen flow through the catalyst in the tube. The catalyst does not need a pretreatment process such as reduction or oxidation, and can directly catalytically convert ethanol into acetaldehyde with high efficiency. The application has high raw material conversion rate and product selectivity, a long continuous operation cycle, relatively low control temperature and three-agent cost, and simple operation steps, and has a good industrial application prospect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of industrial catalysis, and relates to application of a catalyst without activation and with stable performance in preparation of acetaldehyde from ethanol oxidation. BACKGROUND

[0002] Acetaldehyde is a two-carbon reagent and an electrophile in organic synthesis, and is an important organic chemical intermediate. Acetaldehyde has original chirality and high industrial application value, and is mainly used as a reducing agent, a fungicide, a flavorant, and a standard solution for determination of aldehydes by colorimetry; and is used in industry to manufacture polyacetaldehyde, butanediol, acetic acid, vinyl acetate, ethyl acetate, acetic anhydride, ethanol, ethyl acetal, synthetic rubber, synthetic resin, pentaerythritol, n-butanol, crotonaldehyde, pyridine, pesticides, medicines and the like.

[0003] The main methods for producing acetaldehyde in industry include ethanol oxidation method, ethylene oxidation method and acetylene hydration method. Among them, the acetylene hydration method is an early production method of acetaldehyde, but due to the problem of mercury pollution, it has been gradually replaced by the ethylene oxidation method. The ethylene oxidation method uses petrochemical product ethylene as raw material, and uses palladium chloride / copper chloride as catalyst to carry out liquid phase oxidation in hydrochloric acid solution to obtain acetaldehyde. This method has problems such as high cost, serious equipment corrosion, danger, environmental pollution, difficult recovery of catalyst, and difficult large-scale continuous production. Since ethylene is heavily dependent on fossil energy, the successful industrialization of ethanol synthesized by biomass route and coal-based route will improve the production efficiency of ethanol and further reduce the cost. The ethanol oxidation method conforms to the concept of green and sustainable development, has the advantages of high atom economy, fast reaction rate, environmental friendliness, easy separation and suitability for large-scale continuous production, and therefore the ethanol oxidation method is expected to become the mainstream method for producing acetaldehyde worldwide.

[0004] The mature ethanol oxidation method is to pass the mixed gas of ethanol vapor and air into a fixed bed reactor containing Ag catalyst, and the oxidation reaction occurs at 450-640 DEG C to generate acetaldehyde. Among them, the single-pass conversion rate of ethanol is 30-75%, the selectivity of acetaldehyde is 85-95%, and the catalyst is replaced every 2-3 months. Although this method has certain advantages compared with the ethylene oxidation method and the acetylene hydration method, it still has the disadvantages of high operating temperature, low raw material conversion rate and product selectivity, expensive and short service life of catalyst, which increases the consumption and reduces the economic efficiency of the process. SUMMARY

[0005] The purpose of the present application is to provide an application of a catalyst without activation and with stable performance in preparation of acetaldehyde from ethanol oxidation, which effectively reduces the process consumption and improves the technical economy.

[0006] In order to achieve the purpose of the present application, the following technical solutions are adopted:

[0007] The present application protects the application of a catalyst without activation and stable performance in the oxidation of ethanol to acetaldehyde, and the specific method is as follows: the catalyst is loaded in the tube of a shell-and-tube reactor, and ethanol and oxygen flow through the catalyst in the tube to catalyze the reaction of ethanol and oxygen to generate acetaldehyde; that is, when ethanol and oxygen flow through this catalyst without activation and stable performance together, this (ternary bulk catalyst with composite oxide structure) catalyst efficiently catalytically converts ethanol into acetaldehyde.

[0008] Further, in this application, the space velocity of the feed liquid of the ethanol is 6.0-10.0 h -1 (especially 6.0 h -1 , 6.5 h -1 , 7.0 h -1 , 7.5 h -1 , 8.0 h -1 , 8.5 h -1 , 9.0 h -1 , 9.5 h -1 , 10.0 h -1 , etc.).

[0009] Further, in this application, the mass fraction of oxygen at the inlet of the reactor is 8.0-20.0% (especially 8.0%, 9.0%, 10.0%, 11.0%, 12.0%, 13.0%, 14.0%, 15.0%, 16.0%, 17.0%, 18.0%, 19.0%, 20.0%, etc.).

[0010] Further, in this application, the control temperature of the reaction of ethanol and oxygen is 230-290℃ (especially 230℃, 240℃, 250℃, 260℃, 270℃, 280℃, 290℃, etc.), and the pressure is 0-40 kPa (especially 0 kPa, 10 kPa, 20 kPa, 30 kPa, 40 kPa, etc.).

[0011] A catalyst without activation and stable performance is used in the above application, and the catalyst is composed of Mo, Fe, X, and O, and its chemical formula is Mo α ·Fe β ·X γ ·O δ ; wherein X is Se or Te, α is 0.9-3.0, β is 0.6-1.5, γ is 0.001-0.1, and δ is a positive number that maintains the algebraic sum of the valence of each element to be 0.

[0012] Further, the active component of the catalyst is Fe2(MoO4)3, and X is an auxiliary agent.

[0013] Further, the catalyst has a molar ratio of Mo to Fe of 1.50-1.74.

[0014] The catalyst is a ternary bulk catalyst having a composite oxide structure.

[0015] A method for preparing a catalyst without activation and stable performance, which is prepared by a step-by-step wet mixing process, and the specific steps are as follows:

[0016] First, a certain amount of industrial MoO3, Fe(NO)3·9H2O, H2SeO4 (SeO2 can also be used) or H6TeO6 (TeO3 can also be used) is calculated and weighed according to the atomic stoichiometric number; secondly, Fe(NO)3·9H2O, H2SeO4 (SeO2 can also be used) or H6TeO6 (TeO3 can also be used) is finely ground and uniformly mixed to obtain material A; then MoO3 is finely ground under the action of a small amount of solvent (methanol, ethanol, ethylene glycol or glycerol) to obtain material B; A is then added to B, finely ground and uniformly mixed to obtain material C; finally, C is calcined and shaped to obtain a ternary bulk inorganic material Mo α ·Fe β ·X γ ·O δ .

[0017] The step-by-step wet mixing process does not require filtration, washing and drying, and has fewer steps; the fine grinding and mixing process is carried out at room temperature, which is low in energy consumption and short in time; the entire process does not produce waste water and solid waste, solving the problems of molybdenum loss and iron loss, and being green, economical and environmentally friendly; and the processing cost of the ternary bulk inorganic material having a composite oxide structure is greatly reduced.

[0018] In addition, the crystal water in Fe(NO)3·9H2O is conducive to the fine grinding and uniform mixing of Fe(NO)3·9H2O, H2SeO4 (SeO2 can also be used) or H6TeO6 (TeO3 can also be used); methanol, ethanol, ethylene glycol or glycerol are all solvents rich in hydroxyl groups, and the excellent affinity and adsorption of hydroxyl groups not only help MoO3 to be finely ground and uniformly dispersed, but also help Fe(NO)3·9H2O, H2SeO4 (SeO2 can also be used) or H6TeO6 (TeO3 can also be used) to form a strong interaction with the surface of molybdenum trioxide, so as to help MoO3, Fe(NO)3·9H2O, H2SeO4 (SeO2 can also be used) or H6TeO6 (TeO3 can also be used) to be finely ground and uniformly mixed, and finally form a stable and repeatable ternary bulk catalyst Mo α ·Fe β ·X γ ·O δTo give full play to the synergistic effect of each component, improve the activity, selectivity and stability of the catalyst.

[0019] Compared with the prior art, the application has the following beneficial effects:

[0020] 1. The application abandons the traditional and expensive silver catalyst, and uses a relatively inexpensive iron-molybdenum catalyst, and the molybdenum-iron ratio and Se or Te content of the catalyst are low, which greatly reduces the cost of the three agents.

[0021] 2. The special formula design makes the used catalyst perform excellently when used for ethanol oxidation to produce acetaldehyde: the ethanol single-pass conversion rate can reach 95%, and the acetaldehyde selectivity can reach 97%. (1) The Se or Te in the used catalyst is a VA oxygen group element, which can exist in +6 valence, and also in -2, -1, 0, +1, +2, +4 valence, and the two elements can change valence according to the different environments. Se or Te exists in high valence as an additive, and when the ethanol oxidation reaction occurs, Se or Te is reduced to low valence, and then is quickly oxidized to high valence by O2 in the reaction gas flow, and this cycle is repeated. Se or Te acts as an efficient oxygen carrier to transfer oxygen in the gas flow to the product, which is beneficial to the full conversion of ethanol to acetaldehyde, thereby improving the raw material conversion rate and product selectivity; (2) The molybdenum-iron ratio of the used catalyst is low, only 1.50-1.74, and this design value ensures the combination of Mo and Fe while improving the mass fraction of the active component Fe2(MoO4)3 in the catalyst, thereby improving the catalytic performance.

[0022] 3. When used for ethanol oxidation to produce acetaldehyde, the used catalyst does not need to be activated with H2 or O2 before use, unlike other methods, and can be directly used for feeding and operation, and the operation temperature is low, the ethanol single-pass conversion rate and the acetaldehyde selectivity are high, the stable operation time is long, the process consumption is reduced, and the technical economy is improved.

[0023] 4. The Mo α ·Fe β ·X γ ·O δ of the catalyst used in the application is a ternary bulk inorganic material with a composite oxide structure, the components of the catalyst are well dispersed, the structure and performance are stable and repeatable, the synergistic effect is significant, and the catalyst performs excellently when used for ethanol oxidation to produce acetaldehyde, and has good industrial application prospect. DETAILED DESCRIPTION

[0024] All features disclosed in this specification, and all steps of any methods or processes disclosed, may be combined in any combination, except combinations where at least some of the features and / or steps are mutually exclusive.

[0025] Any feature in the foregoing specification (including any accompanying claims, abstract and drawings) can be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature is one example only of a generic series of equivalent or similar features.

[0026] The features and properties of the present application will become further apparent to those of ordinary skill in the art upon consideration of the following detailed description of the application, taken in conjunction with the accompanying drawings.

[0027] Example 1

[0028] First, 272.6g, 500.0g, 9.9g of MoO3, Fe(NO)3-9H2O, H2SeO4 of industrial grade were weighed respectively; second, the weighed Fe(NO)3-9H2O and H2SeO4 were mixed, finely ground and mixed uniformly to obtain material A; then, 93 mL of methanol was added to the weighed MoO3, mixed, finely ground and uniformly dispersed to obtain material B; A was added to B, finely ground and mixed uniformly to obtain material C; finally, the C was calcined at 340°C for 9.0h, and then shaped to obtain the ternary bulk catalyst Mo 2.22 ·Fe 1.45 ·Se 0.08 ·O 8.995 .

[0029] The obtained ternary bulk catalyst Mo 2.22 ·Fe 1.45 ·Se 0.08 ·O 8.995 was loaded in the tube of a shell-and-tube reactor, without activation, and ethanol and oxygen were directly passed through the catalyst Mo 2.22 ·Fe 1.45 ·Se 0.08 ·O 8.995 in the tube to catalyze the reaction of ethanol and oxygen under the conditions of controlling the temperature at 280°C, the pressure at 30 kPa, the feed liquid space velocity of ethanol at 7.0h -1 -1, and the mass fraction of oxygen at the inlet of the reactor at 19.8%. The reaction products were condensed, and the obtained liquid and gas phase products were respectively analyzed by chromatography. Through carbon balance and catalytic performance index calculation, the ethanol single-pass conversion rate was 100.0%, and the formaldehyde selectivity was 97.0%.

[0030] Example 2

[0031] First, weigh 305.4g, 500.0g, 18.0g of MoO3, Fe(NO)3-9H2O, TeO3 of industrial grade respectively; second, mix Fe(NO)3-9H2O and TeO3 weighed, grind and mix well to get material A; then, add 52ml of glycerol to MoO3 weighed, mix and grind well to disperse evenly to get material B; add A to B, grind and mix well to get material C; finally, calcine C at 370℃ for 6.5h, then shape to get ternary bulk catalyst Mo 1.2 ·Fe 0.7 ·Te 0.058 ·O 4.824 .

[0032] Load the ternary bulk catalyst Mo 1.2 ·Fe 0.7 ·Te 0.058 ·O 4.824 with composite oxide structure obtained into the tube of shell-and-tube reactor, without activation, directly make ethanol and oxygen-nitrogen flow through the catalyst Mo 1.2 ·Fe 0.7 ·Te 0.058 ·O 4.824 ( control the feed liquid space velocity of ethanol to be 9.0h -1 , the mass fraction of oxygen at the inlet of reactor to be 10.0%), catalyze the reaction of ethanol and oxygen under the condition of controlling temperature to be 230℃ and pressure to be 2kPa, condense the reaction product, analyze the liquid and gas phase product obtained by chromatography respectively, calculate by carbon balance and catalytic performance index, get the conversion rate of ethanol to be 95.8% and the selectivity of acetaldehyde to be 99.1%.

[0033] Example 3

[0034] First, weigh 284.7g, 500.0g, 0.5g of MoO3, Fe(NO)3-9H2O, SeO2 of industrial grade respectively; second, mix Fe(NO)3-9H2O and SeO2 weighed, grind and mix well to get material A; then, add 116ml of ethanol to MoO3 weighed, mix and grind well to disperse evenly to get material B; add A to B, grind and mix well to get material C; finally, calcine C at 360℃ for 7.0h, then shape to get ternary bulk catalyst Mo 1.71 ·Fe 1.07 ·Se 0.004 ·O 6.743 .

[0035] Load the ternary bulk catalyst Mo 1.71• Fe 1.07 • Se 0.004 • O 6.743 The obtained ternary bulk catalyst Mo 1.71 • Fe 1.07 • Se 0.004 • O 6.743 The obtained ternary bulk catalyst Mo -1 was packed in the tube of a shell-and-tube reactor, and ethanol was directly reacted with oxygen and nitrogen flow through the catalyst Mo 3.63 • Fe 1.45 • Se 0.08 • O 13.225 without activation, under the conditions of controlling the temperature at 260°C, the pressure at 18 kPa, and the mass fraction of oxygen at the inlet of the reactor at 14.5%, and the reaction was continuously operated for 2500 h. The results of the initial and end reactions were selected by carbon balance and catalytic performance index calculation and are listed in the following table:

[0036] Time h Ethanol conversion % per pass Acetaldehyde selectivity % 0 97.8 98.3 2500 96.1 98.2

[0037] Comparative Example 1

[0038] First, 446.0 g, 500.0 g, and 9.9 g of industrial MoO3, Fe(NO)3·9H2O, and H2SeO4, respectively, were weighed. Second, the weighed Fe(NO)3·9H2O and H2SeO4 were mixed, finely ground, and uniformly mixed to obtain material A. Third, 125 mL of methanol was added to the weighed MoO3, mixed, finely ground, and uniformly dispersed to obtain material B. Fourth, A was added to B, finely ground, and uniformly mixed to obtain material C. Finally, the obtained ternary bulk catalyst Mo 3.63 • Fe 1.45 • Se 0.08 • O 13.225 with a composite oxide structure was calcined at 340°C for 9.0 h, and then shaped to obtain the ternary bulk catalyst Mo

[0039] The obtained ternary bulk catalyst Mo 3.63 • Fe 1.45 • Se 0.08 • O 13.225 with a composite oxide structure was calcined at 340°C for 9.0 h, and then shaped to obtain the ternary bulk catalyst Mo 3.63 • Fe 1.45 • Se 0.08 • O 13.225 without activation, under the conditions of controlling the temperature at 260°C, the pressure at 18 kPa, and the mass fraction of oxygen at the inlet of the reactor at 14.5%, and the reaction was continuously operated for 2500 h. The results of the initial and end reactions were selected by carbon balance and catalytic performance index calculation and are listed in the following table: -1The reaction product was condensed, and the liquid and gaseous products were analyzed by chromatography. The carbon balance and catalytic performance index were calculated, and the ethanol conversion rate was 83.9%, and the formaldehyde selectivity was 81.1%.

[0040] Comparative Example 2

[0041] First, 305.4 g and 500.0 g of MoO3 and Fe(NO)3·9H2O of industrial grade were weighed respectively; second, the weighed Fe(NO)3·9H2O was finely ground to obtain material A; then, 52 mL of glycerol was added to the weighed MoO3, which was mixed and finely ground to be uniformly dispersed to obtain material B; then, A was added to B, which was finely ground and mixed uniformly to obtain material C; finally, the C was calcined at 370℃ for 6.5 h, and then was shaped to obtain the ternary bulk catalyst Mo 1.2 ·Fe 0.7 ·O 4.65 .

[0042] The obtained ternary bulk catalyst Mo 1.2 ·Fe 0.7 ·O 4.65 was loaded in the tube of a shell-and-tube reactor, and ethanol and oxygen were directly flowed through the catalyst Mo 1.2 ·Fe 0.7 ·O 4.65 without activation (the feed liquid space velocity of ethanol was controlled at 9.0 h -1 , and the mass fraction of oxygen at the inlet of the reactor was 10.0%), and the reaction of ethanol and oxygen was catalyzed under the condition that the temperature was controlled at 360℃ and the pressure was controlled at 2 kPa. The reaction product was condensed, and the liquid and gaseous products were analyzed by chromatography. The carbon balance and catalytic performance index were calculated, and the ethanol conversion rate was 90.5%, and the acetaldehyde selectivity was 89.7%.

[0043] Comparative Example 3

[0044] First, 284.7 g, 500.0 g and 25.7 g of MoO3, Fe(NO)3·9H2O and SeO2 of industrial grade were weighed respectively; second, the weighed Fe(NO)3·9H2O and SeO2 were mixed, finely ground and mixed uniformly to obtain material A; then, 116 mL of ethanol was added to the weighed MoO3, which was mixed and finely ground to be uniformly dispersed to obtain material B; then, A was added to B, which was finely ground and mixed uniformly to obtain material C; finally, the C was calcined at 360℃ for 7.0 h, and then was shaped to obtain the ternary bulk catalyst Mo 1.71 ·Fe1.07 • Se 0.2 • O 6.935 The obtained ternary bulk catalyst Mo 1.71 • Fe 1.07 • Se 0.2 • O 6.935 was directly used to catalyze the reaction of ethanol with oxygen without activation, and the catalyst Mo 1.71 • Fe 1.07 • Se 0.2 • O 6.935 The feed liquid space velocity of ethanol was controlled at 8.0 h -1 , the mass fraction of oxygen at the inlet of the reactor was 14.5%, and the reaction of ethanol with oxygen was catalyzed under the conditions of a temperature of 260℃ and a pressure of 180 kPa (the reaction products were condensed, and the obtained liquid and gas phase products were respectively analyzed by chromatography). The reaction was continuously operated for 2500 h, and the results at the beginning and the end of the reaction were selected by carbon balance and catalytic performance index calculation and were listed in the following table:

[0045] Time h Ethanol conversion % per pass Acetaldehyde selectivity % 0 88.0 87.6 2500 72.5 84.1

[0046] The above-described embodiments only express the specific implementation of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the protection scope of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the technical concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application.

[0047] This Background section is provided for generally presenting the context of the application, the work of the present inventors, the work described in this Background section and the descriptions in this section are not, either expressly or impliedly, admitted to be prior art against the present application.

Claims

1. The application of a catalyst that requires no activation and has stable performance in the oxidation of ethanol to acetaldehyde, characterized in that: This ternary bulk catalyst with a composite oxide structure is packed into the tube of a shell-and-tube reactor, allowing ethanol and oxygen / nitrogen to flow through the catalyst in the tube. This catalyst can directly and efficiently catalyze the reaction of ethanol and oxygen to produce acetaldehyde without the need for pretreatment processes such as reduction or oxidation. The catalyst is composed of Mo, Fe, X, and O elements, and its chemical formula is Mo. α ·Fe β ·X γ ·O δ Where X is Se or Te, α is 0.9-3.0, β is 0.6-1.5, γ is 0.001-0.1, and δ is a positive number that keeps the algebraic sum of the valences of the elements at zero. The active component of the catalyst is Fe2(MoO4)3, and X is an additive; the molar ratio of Mo to Fe in the catalyst is 1.50-1.

74. The preparation method of this catalyst includes the following steps: 1) Weigh out MoO3, Fe(NO3)3·9H2O and raw materials containing Se or Te according to the proportion, then grind Fe(NO3)3·9H2O and raw materials containing Se or Te thoroughly and mix them evenly to obtain material A; The raw materials containing Se or Te are H2SeO4 or SeO2, H6TeO6 or TeO3; 2) Grind MoO3 thoroughly in the presence of a solvent to obtain material B; 3) Add material A to material B, grind thoroughly and mix evenly to obtain material C; 4) Calcining and molding material C yields a ternary bulk catalyst with a composite oxide structure, namely Mo. α ·Fe β ·X γ ·O δ .

2. The application according to claim 1, characterized in that: The feed liquid hourly space velocity (LHSV) for the ethanol is 6.0-10.0 h⁻¹. -1 .

3. The application according to claim 1, characterized in that: The mass fraction of oxygen at the reactor inlet is 8.0-20.0%.

4. The application according to claim 1, characterized in that: The temperature for the reaction of ethanol with oxygen is 230-290℃, and the pressure is 0-40kPa.

5. The application according to claim 1, characterized in that: The solvent mentioned in step 2) is methanol, ethanol, ethylene glycol or glycerol.

6. The application according to claim 1, characterized in that: The calcination temperature in step 4) is 330-380℃, and the time is 6.0-10.0h.

7. A catalyst that requires no activation and has stable performance, characterized in that: The catalyst is composed of Mo, Fe, X, and O elements, and its chemical formula is Mo. α ·Fe β ·X γ ·O δ Where X is Se or Te, α is 0.9-3.0, β is 0.6-1.5, γ is 0.001-0.1, and δ is a positive number that keeps the algebraic sum of the valences of the elements at zero. The active component of the catalyst is Fe2(MoO4)3, and X is an additive; the molar ratio of Mo to Fe in the catalyst is 1.50-1.

74. The preparation method of this catalyst includes the following steps: 1) Weigh out MoO3, Fe(NO3)3·9H2O and raw materials containing Se or Te according to the proportion, then grind Fe(NO3)3·9H2O and raw materials containing Se or Te thoroughly and mix them evenly to obtain material A; The raw materials containing Se or Te are H2SeO4 or SeO2, H6TeO6 or TeO3; 2) Grind MoO3 thoroughly in the presence of a solvent to obtain material B; 3) Add material A to material B, grind thoroughly and mix evenly to obtain material C; 4) Calcining and molding material C yields a ternary bulk catalyst with a composite oxide structure, namely Mo. α ·Fe β ·X γ ·O δ .

8. The catalyst according to claim 7, characterized in that: The solvent mentioned in step 2) is methanol, ethanol, ethylene glycol or glycerol.

9. The catalyst according to claim 7, characterized in that: The calcination temperature in step 4) is 330-380℃, and the time is 6.0-10.0h.

10. A method for preparing a catalyst that requires no activation and has stable performance, characterized in that: The catalyst is composed of Mo, Fe, X, and O elements, and its chemical formula is Mo. α ·Fe β ·X γ ·O δ Where X is Se or Te, α is 0.9-3.0, β is 0.6-1.5, γ is 0.001-0.1, and δ is a positive number that keeps the algebraic sum of the valences of the elements at zero. The active component of the catalyst is Fe2(MoO4)3, and X is an additive; the molar ratio of Mo to Fe in the catalyst is 1.50-1.

74. The preparation method includes the following steps: 1) Weigh out MoO3, Fe(NO3)3·9H2O and raw materials containing Se or Te according to the proportion, then grind Fe(NO3)3·9H2O and raw materials containing Se or Te thoroughly and mix them evenly to obtain material A; The raw materials containing Se or Te are H2SeO4 or SeO2, H6TeO6 or TeO3; 2) Grind MoO3 thoroughly in the presence of a solvent to obtain material B; 3) Add material A to material B, grind thoroughly and mix evenly to obtain material C; 4) Calcining and molding material C yields a ternary bulk catalyst with a composite oxide structure, namely Mo. α ·Fe β ·X γ ·O δ .

11. The method for preparing the catalyst according to claim 10, characterized in that: The solvent mentioned in step 2) is methanol, ethanol, ethylene glycol or glycerol.

12. The method for preparing the catalyst according to claim 10, characterized in that: The calcination temperature in step 4) is 330-380℃, and the time is 6.0-10.0h.