Zirconium-containing catalyst, preparation method and application thereof, and method for preparing butadiene from ethanol and acetaldehyde

Abstract

The present invention provides a zirconium-containing catalyst, a preparation method thereof, and an application thereof. The catalyst comprises a mesoporous silica support and zirconium oxide loaded on the support, wherein the alkaline amount of the mesoporous silica support is ≤5μmol / g, and the average pore size of the mesoporous silica support is ≥4nm. The method comprises: using mesoporous silica as a raw material, acid-washing, and then calcining at a temperature of 700-800°C to obtain a mesoporous silica support; depositing a precursor of elemental zirconium on the mesoporous silica support, drying, and then calcining. The present invention provides a method for preparing butadiene from ethanol and acetaldehyde. The catalyst of the present invention is used for preparing butadiene from ethanol in a two-step process, and is converted into butadiene by feeding an ethanol-acetaldehyde-water mixed solution, producing significant performance advantages in terms of catalytic activity and selectivity obtained at a given reaction temperature.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalysts and relates to a zirconium catalyst for converting ethanol into 1,3-butadiene and an application thereof. Background Art

[0002] 1,3-Butadiene is widely used in the chemical industry. It is the primary raw material for the synthesis of styrene-butadiene rubber (SBR), polybutadiene rubber (BR), chloroprene rubber, and nitrile rubber. SBR accounts for the largest share, followed by polybutadiene rubber (primarily butadiene rubber). Butadiene is also used in the production of styrene-butadiene latex, ABS resin, and adiponitrile, the latter a raw material for nylon 66. Currently, the C4 fraction, a byproduct of steam cracking ethylene production, is the primary source of butadiene. Approximately 97% of global plants utilize extraction processes using a C4 mixture from steam cracking. However, the recent rise in oil prices and the impact of the global trend toward lighter steam cracking feedstocks on butadiene production have necessitated the development of alternative methods for butadiene production.

[0003] There are two main methods for producing butadiene from ethanol: a one-step method and a two-step method. The one-step method uses ethanol as a single feedstock to produce butadiene in one step. The two-step method first dehydrogenates ethanol into acetaldehyde in one reactor, and then uses the ethanol and acetaldehyde mixture as raw materials to convert it into butadiene in another reactor. The complete reaction pathway for producing butadiene from ethanol is as follows: (1) A portion of ethanol is first dehydrogenated to produce acetaldehyde; (2) Two molecules of acetaldehyde then undergo an aldol condensation reaction to produce 3-hydroxybutyraldehyde; (3) 3-hydroxybutyraldehyde is then dehydrated to produce 2-butenal; (4) 2-butenal then reacts with ethanol to undergo an intermolecular hydrogen transfer reaction of MPVO to convert it into 2-butenol, and ethanol is dehydrogenated to produce acetaldehyde again; (5) Finally, 2-butenol is dehydrated to form butadiene.

[0004] (1) CH3CH2OH→CH3CHO+H2

[0005] (2) 2CH3CHO→CH3-CHOH-CH2-CHO

[0006] (3)CH3-CHOH-CH2-CHO→CH3-CH=CH-CHO+H2O

[0007] (4)CH3-CH=CH-CHO+CH3CH2OH→CH3-CH=CH-CH2OH+CH3CHO

[0008] (5)CH3-CH=CH-CH2OH→CH2=CH-CH=CH2

[0009] There are many side reactions during the reaction process, especially the dehydration of ethanol to produce ethylene, the polymerization of ether and aldehyde to produce heavy components with more than five carbon atoms, and other reactions may also occur (such as cracking, hydrogenation, cyclization, Diels-Alder reaction, etc.).

[0010] GB 331482 describes a process for preparing butadiene in which ethanol is contacted with an alumina catalyst mixed with zinc oxide for reaction, but the yield of butadiene is as low as 18%.

[0011] B Corson et al. (Ind. Eng. Chem. 1949, 41, 1012-1017) describe a two-step process for the preparation of butadiene. In the first step, ethanol is dehydrogenated to acetaldehyde. In the second step, the resulting acetaldehyde is mixed with ethanol and converted to butadiene over a catalyst. Using the most efficient catalyst comprising 2.3 wt% tantalum oxide on amorphous silica, a butadiene selectivity of up to 69% and a feedstock conversion of 34% were achieved over 8 hours of online production.

[0012] CN105451881A introduces a method for preparing butadiene. The catalyst used is a zeolite material having a framework structure containing one or more tetravalent elements, wherein at least a portion of the elements contained in the framework structure are isomorphously substituted with one or more elements X. The zeolite material is preferably BEA or MWW zeolite, and X is most preferably Ti and / or Sn and / or Ta.

[0013] Vitaly L. Sushkevich et al. (ACS Catal. 2015, 5, 4833-4836) introduced a reaction mechanism for the conversion of ethanol to 1,3-butadiene. The catalyst used was an Ag / Zr-Beta molecular sieve synthesized by dealuminizing Beta molecular sieves through acid treatment. The initial selectivity for butadiene reached approximately 70%, but the catalyst deactivated rapidly. Summary of the Invention

[0014] The object of the present invention is to provide a new zirconium-containing catalyst and a preparation method thereof. The zirconium-containing catalyst comprises a mesoporous silica carrier and zirconium oxide loaded on the carrier, wherein the basic site amount of the mesoporous silica carrier is ≤5 μmol / g.

[0015] According to the first aspect of the present invention, the present invention provides a zirconium-containing catalyst, which contains a mesoporous silica carrier and zirconium oxide loaded on the carrier, the alkaline content of the mesoporous silica carrier is ≤5μmol / g, and the average pore size of the mesoporous silica carrier is ≥4nm.

[0016] According to the second aspect of the present invention, the present invention provides a method for preparing the catalyst described in the present invention, wherein the method comprises: using mesoporous silica as a raw material, acid washing, and then calcining at a temperature of 700-800°C to obtain a mesoporous silica carrier; depositing a precursor of elemental zirconium on the mesoporous silica carrier, drying and then calcining, and the average pore diameter of the mesoporous silica raw material is above 4nm.

[0017] According to a third aspect of the present invention, the present invention provides use of the catalyst of the present invention in the reaction of preparing butadiene from ethanol and acetaldehyde.

[0018] According to a fourth aspect of the present invention, a method for preparing butadiene from ethanol and acetaldehyde is provided, the method comprising: in a fixed bed reactor, passing a mixed solution of ethanol-acetaldehyde-water raw material through a bed of a supported catalyst, wherein the supported catalyst is the catalyst described in the present invention.

[0019] The catalyst preparation method of the present invention improves the performance of the catalyst for producing butadiene from a mixture of ethanol and acetaldehyde in a two-step process by appropriately pretreating the mesoporous silica carrier (acid washing, high-temperature calcination).

[0020] According to the catalyst of the present invention, through CO2-TPD (CO2 temperature programmed desorption) analysis, the catalyst prepared by loading 2wt% zirconium oxide on the carrier silica after acid washing and high-temperature calcination has a basic base amount ≤8μmol / g, while the catalyst prepared by loading 2wt% zirconium oxide on silica without the above treatment has a basic base amount ≥12μmol / g.

[0021] The catalyst obtained by the method for preparing the catalyst of the present invention has better selectivity for the target product, which is presumably because the method of the present invention can remove hydroxyl groups on the surface of silica while retaining the high specific surface area of ​​silica, thereby making the catalyst have better selectivity.

[0022] The catalyst of the invention is used for preparing butadiene from ethanol in a two-step process, wherein ethanol-acetaldehyde-water mixed solution is fed and converted into butadiene, and has significant performance advantages in terms of catalytic activity and selectivity obtained at a given reaction temperature. DETAILED DESCRIPTION

[0023] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0024] The invention provides a zirconium-containing catalyst, which contains a mesoporous silica carrier and zirconium oxide loaded on the carrier. The basic amount of the mesoporous silica carrier is ≤5 μmol / g, and the average pore size of the mesoporous silica carrier is ≥4 nm.

[0025] According to a preferred embodiment of the present invention, the mesoporous silica carrier is an amorphous mesoporous silica with random pores and a specific surface area of ​​300 m 2 / g, preferably 320-550m 2 / g, average pore diameter ≥4nm, preferably 4-10nm.

[0026] According to a preferred embodiment of the present invention, the basic position of the mesoporous silica carrier has an alkali content of ≤5 μmol / g, preferably 0.5-5 μmol / g, thereby improving the selectivity of the catalyst for the target product.

[0027] According to a preferred embodiment of the present invention, when the mesoporous silica carrier carries a catalyst containing 1-6 wt% of zirconium oxide, the basic site amount of the catalyst is 2-18 μmol / g.

[0028] According to a preferred embodiment of the present invention, the specific surface area of ​​the catalyst is ≥300m 2 / g, preferably 300-550m 2 / g; average pore diameter ≥4nm, preferably 4-10nm.

[0029] In the present invention, the amount of zirconium oxide can be selected in a wide range, and any conventional amount can be used in the present invention. According to a preferred embodiment of the present invention, the mass of zirconium oxide is 1-6% of the mass of the mesoporous support, thereby improving the selectivity and activity of the target product of the catalyst.

[0030] According to a preferred embodiment of the present invention, the mesoporous silica carrier is an amorphous mesoporous silica with random pores and a specific surface area of ​​300 m 2 / g, preferably 320-550m 2 / g; average pore diameter ≥4nm, preferably 4-10nm.

[0031] In the present invention, in order to obtain the catalyst having the aforementioned characteristics of the present invention, the mesoporous silica carrier is preferably obtained by using mesoporous silica as raw material, acid washing, and then calcining at 700-800°C, and the average pore size of the mesoporous silica raw material is above 4nm.

[0032] In the present invention, there is no special requirement for the pickling step, and conventional pickling steps can be used in the present invention. According to the present invention, the pickling acid solution is preferably one or more of nitric acid aqueous solution, hydrochloric acid and citric acid aqueous solution.

[0033] According to a more preferred embodiment of the present invention, the concentration of the pickling acid solution is preferably 0.1M to 5M.

[0034] In the present invention, there are no special requirements for the pickling conditions. According to the preferred embodiment of the present invention, the pickling conditions include: a temperature of 50°C to 100°C; the pickling time is determined according to the temperature and the type of acid solution. According to the present invention, the preferred pickling time is 1 hour to 8 hours.

[0035] According to a preferred embodiment of the present invention, the preparation steps of the mesoporous silica carrier preferably include: contacting the mesoporous silica raw material with an acid solution with a concentration of 0.1M to 5M at a temperature of 50°C to 100°C for acid washing, and the contact time is 1 hour to 8 hours. After the acid washing is completed, washing with deionized water until neutral, filtering, placing the solid in a drying oven to dry, and then calcining it at 700°C to 800°C in a muffle furnace. The average pore size of the mesoporous silica raw material is above 4nm.

[0036] In the present invention, the aforementioned carrier is used to prepare the catalyst of the present invention so that both the activity of the catalyst and the selectivity of the target product can be greatly improved.

[0037] The present invention has no special requirements for the preparation method of the catalyst. As long as the catalyst has the aforementioned properties, the purpose of the present invention can be achieved.

[0038] According to a preferred embodiment of the present invention, the present invention provides a method for preparing the catalyst described in the present invention, wherein the method comprises: using mesoporous silica as a raw material, acid washing, and then calcining at a temperature of 700-800°C to obtain a mesoporous silica carrier; depositing a precursor of elemental zirconium on the mesoporous silica carrier, drying and then calcining, wherein the average pore diameter of the mesoporous silica raw material is above 4nm.

[0039] In the present invention, there is no special requirement for the pickling step, and conventional pickling steps can be used in the present invention. According to the present invention, the pickling acid solution is preferably one or more of nitric acid aqueous solution, hydrochloric acid and citric acid aqueous solution.

[0040] According to a more preferred embodiment of the present invention, the concentration of the pickling acid solution is preferably 0.1M to 5M, preferably 0.5M to 5M.

[0041] According to a preferred embodiment of the present invention, the volume of the acid solution is 2-10 times the volume of the mesoporous silica raw material. 5 times is used as an example to illustrate the advantages of the present invention, but the scope of the present invention is not limited thereby.

[0042] In the present invention, there are no special requirements for the pickling conditions. According to the preferred embodiment of the present invention, the pickling conditions include: a temperature of 50°C to 100°C; the pickling time is determined according to the temperature and the type of acid solution. According to the present invention, the pickling time is preferably 1 hour to 8 hours, preferably 1 hour to 3 hours.

[0043] According to a preferred embodiment of the present invention, the specific surface area of ​​the mesoporous silica raw material is 300-660m 2 / g, the pore volume is 0.6-1.2mL / g, and the average pore diameter is 4-10nm.

[0044] According to a preferred embodiment of the present invention, the method for preparing the catalyst comprises:

[0045] ① The mesoporous silica raw material is contacted with at least one acid solution with a concentration of 0.1M to 5M at a temperature of 50°C to 100°C for a contact time of 1 hour to 8 hours. After the acid wash, the carrier is washed with deionized water until neutral, filtered, and the solid is placed in a drying oven to dry;

[0046] ② calcining the solid obtained in step ① at 700°C to 800°C in a muffle furnace to obtain a carrier;

[0047] ③ depositing the elemental zirconium precursor on the mesoporous silica support obtained in step ②;

[0048] ④ The solid obtained from step ③ was placed in a drying oven for drying and finally calcined in a muffle furnace.

[0049] According to the method of the present invention, as needed, deionized water is used for rinsing to remove excess acid and impurities washed away. This can be carried out at the same temperature as the above-mentioned acid washing or at room temperature.

[0050] According to a preferred embodiment of the present invention, the preferred drying conditions include: 100-120° C., and a drying time of 12-24 h.

[0051] According to a preferred embodiment of the present invention, the catalyst is calcined at 500-650° C. for 3-6 hours.

[0052] According to the present invention, the preparation process of the catalyst comprises the following steps:

[0053] ① The carrier silica is contacted with at least one acid with a concentration of 0.1M to 5M at a temperature of 50°C to 100°C for a contact time of 1 hour to 8 hours. After the acid wash, the carrier is washed with deionized water until neutral, filtered, and the solid is placed in a drying oven to dry;

[0054] ② calcining the solid obtained in step ① at 700°C to 800°C in a muffle furnace to obtain a carrier;

[0055] ③ depositing the elemental zirconium precursor on the mesoporous silica support obtained in step ②;

[0056] ④ The solid obtained in step ③ is placed in a blast drying oven at a constant temperature of 100-120° C. for 12-24 hours, and finally placed in a muffle furnace for calcination at a temperature of 500-650° C. for 3-6 hours.

[0057] The catalyst of the present invention is particularly suitable for use in a method for preparing butadiene from ethanol and acetaldehyde, and has the advantage of better selectivity for butadiene products.

[0058] The present invention provides a method for preparing butadiene from ethanol and acetaldehyde. The method comprises: in a fixed bed reactor, passing a mixed solution of ethanol, acetaldehyde and water through a bed of a supported catalyst, wherein the supported catalyst is the catalyst described in the present invention.

[0059] According to a preferred embodiment of the present invention, the operating conditions in the fixed bed reactor include: a temperature of 300-400°C, preferably 310-350°C.

[0060] According to a preferred embodiment of the present invention, the operating conditions in the fixed bed reactor include: the pressure is normal pressure.

[0061] According to a preferred embodiment of the present invention, the operating conditions in the fixed bed reactor include: the raw material mass space velocity is 0.5-5h -1 , the preferred raw material mass space velocity is 0.8-3h -1 .

[0062] According to a preferred embodiment of the present invention, the molar ratio of ethanol to acetaldehyde in the raw material solution is 2:1 to 5:1, and the mass of water accounts for 5-50% of the mass of the total solution.

[0063] According to a preferred embodiment of the present invention, the molar ratio of ethanol to acetaldehyde in the raw material solution is 2.5:1-4:1, and the mass of water accounts for 8-30% of the mass of the total solution.

[0064] The following examples will further illustrate the application of the catalyst provided by the present invention. These examples are only illustrative and are not intended to limit the present invention.

[0065] Definition of terms:

[0066]

[0067] Description of the catalytic activity test process

[0068] In the following examples, the catalyst activity tests were conducted using a fixed-bed reactor. A tubular furnace with three heating zones was used to control the reactor temperature, and a dual-piston pump was used for liquid feeding. The products formed during the reaction remained in the gas phase and were analyzed online using an Agilent 7890A gas chromatograph. Specific operating conditions are described in the following examples.

[0069] In the following zirconium-based catalyst activity tests, the feed ethanol / acetaldehyde molar ratio was 3.5:1, the water content was 10 wt%, the reaction temperature was 350°C, the pressure was atmospheric, and the feed flow rate was a WHSV of 1 g / g catalyst / h, based on the combined mass of ethanol and acetaldehyde. Under these process conditions, the total conversion of ethanol and acetaldehyde, as well as the carbon selectivity for butadiene, were measured.

[0070] The properties of the mesoporous silica used in the examples are summarized below.

[0071] Table 1

[0072]

[0073] Example 1

[0074] At 50°C, Type B silica gel (Table 1) was placed in a quartz tube. A 5M aqueous nitric acid solution was passed over the silica for 2 hours, using a volume approximately 5 times that occupied by the silica, and the solution was recycled. The acid-washed solid was rinsed with deionized water for an additional hour, then placed in a 110°C oven for 12 hours, and finally calcined in a muffle furnace at 800°C for 3 hours (properties shown in Table 2).

[0075] Dissolve 2.091 g of zirconium nitrate pentahydrate in water. With stirring, quickly add this solution dropwise to 30 g of the treated silica support (equal volumes impregnated). The solid is then allowed to stand for 4 hours and then dried in a 110°C forced air oven for 24 hours. Finally, the dried solid is calcined in a muffle furnace at 550°C in an air atmosphere for 5 hours to obtain a 2% ZrO2 / SiO2 catalyst.

[0076] Example 2

[0077] At 80°C, the Type B silica gel listed in Table 1 was placed in a quartz tube. A 0.1M aqueous nitric acid solution was passed over the silica for 8 hours, using a volume approximately five times that occupied by the silica, and the solution was recycled. The acid-washed solid was rinsed with deionized water for an additional hour, then placed in a 110°C oven for 12 hours, and finally calcined in a muffle furnace at 700°C for 3 hours.

[0078] Dissolve 2.091 g of zirconium nitrate pentahydrate in water. With stirring, quickly add this solution dropwise to 30 g of the treated silica support (equal volumes impregnated). The solid is then allowed to stand for 4 hours and then dried in a 110°C forced air oven for 24 hours. Finally, the dried solid is calcined in a muffle furnace at 550°C in an air atmosphere for 5 hours to obtain a 2% ZrO2 / SiO2 catalyst.

[0079] Example 3

[0080] At 100°C, the Type C silica gel (Table 1) was placed in a quartz tube. A mixture of 0.1M nitric acid and 3M citric acid was passed over the silica for 4 hours. The volume of the solution used was approximately 5 times the volume occupied by the silica and was recycled. The acid-washed solid was rinsed with deionized water for an additional hour, then placed in a 110°C oven for 12 hours and finally calcined in a muffle furnace at 750°C for 3 hours.

[0081] Dissolve 2.091 g of zirconium nitrate pentahydrate in water. With stirring, quickly add this solution dropwise to 30 g of the treated silica support (equal volumes impregnated). The solid is then allowed to stand for 4 hours and then dried in a 110°C forced air oven for 24 hours. Finally, the dried solid is calcined in a muffle furnace at 550°C in an air atmosphere for 5 hours to obtain a 2% ZrO2 / SiO2 catalyst.

[0082] Example 4

[0083] Type B silica gel (Table 1) was placed in a quartz tube at 70°C. A 5M aqueous nitric acid solution was passed over the silica for 2 hours, using a volume approximately 5 times that occupied by the silica, and the solution was recycled. The acid-washed solid was rinsed with deionized water for an additional hour, then placed in a 100°C oven for 12 hours, and finally calcined in a muffle furnace at 800°C for 3 hours.

[0084] Dissolve 4.182g of zirconium nitrate pentahydrate in water. With stirring, quickly add this solution dropwise to 30g of the treated silica support (equal volumes impregnated). The solid is then allowed to stand for 4 hours and then dried in a 110°C forced air oven for 24 hours. Finally, the dried solid is calcined in a muffle furnace at 550°C in an air atmosphere for 5 hours to obtain a 4% ZrO2 / SiO2 catalyst.

[0085] Activity test method: the feed flow rate is 3 g / g catalyst / h WHSV based on the total mass of ethanol and acetaldehyde, and other conditions are the same as in Example 1.

[0086] Comparative Example 1

[0087] Dissolve 2.091g of zirconium nitrate pentahydrate in water. While stirring, quickly add this solution dropwise to 30g of Type B silica gel (Table 1) (equal volumes impregnated). The solid is then allowed to stand for 4 hours and then dried in a 110°C forced air oven for 24 hours. Finally, the dried solid is calcined in a muffle furnace at 550°C in an air atmosphere for 5 hours to obtain a 2% ZrO2 / SiO2 catalyst.

[0088] Comparative Example 2

[0089] At 50°C, the Type B silica gel listed in Table 1 was placed in a quartz tube. A 5M aqueous nitric acid solution was passed over the silica for 2 hours, using a volume approximately 5 times that occupied by the silica, and the solution was recycled. The acid-washed solid was rinsed with deionized water for an additional hour, then placed in a 110°C oven for 12 hours, and finally calcined in a muffle furnace at 500°C for 3 hours.

[0090] Dissolve 2.091 g of zirconium nitrate pentahydrate in water. With stirring, quickly add this solution dropwise to 30 g of the treated silica support (equal volumes impregnated). The solid is then allowed to stand for 4 hours and then dried in a 110°C forced air oven for 24 hours. Finally, the dried solid is calcined in a muffle furnace at 550°C in an air atmosphere for 5 hours to obtain a 2% ZrO2 / SiO2 catalyst.

[0091] Comparative Example 3

[0092] At 50°C, the Type A silica gel listed in Table 1 was placed in a quartz tube. A 5M nitric acid cleaning solution was passed over the silica for 2 hours, using a volume approximately 5 times that occupied by the silica, which was then recycled. The acid-washed solid was rinsed with deionized water for an additional hour, then placed in a 110°C oven for 12 hours, and finally calcined in a muffle furnace at 800°C for 3 hours.

[0093] Dissolve 2.091 g of zirconium nitrate pentahydrate in water. With stirring, quickly add this solution dropwise to 30 g of the treated silica support (equal volumes impregnated). The solid is then allowed to stand for 4 hours and then dried in a 110°C forced air oven for 24 hours. Finally, the dried solid is calcined in a muffle furnace at 550°C in an air atmosphere for 5 hours to obtain a 2% ZrO2 / SiO2 catalyst.

[0094] The properties of the carrier are shown in Table 2, and the activity test results and physicochemical parameters of the catalyst are shown in Table 3.

[0095] Table 2

[0096]

[0097] Table 3

[0098]

[0099] Comparing Example 1 with Comparative Example 1, the catalyst in Example 1 whose carrier silicon dioxide was acid-washed and high-temperature calcined had higher butadiene selectivity than the catalyst in which the carrier silicon dioxide was not acid-washed and high-temperature calcined.

[0100] Comparing Example 1 with Comparative Example 2, the catalyst in Comparative Example 2, whose carrier was only acid-washed but calcined at low temperature, had lower butadiene selectivity, while the catalyst in Example 1, whose carrier was both acid-washed and calcined at high temperature, had higher butadiene selectivity.

[0101] Comparing Example 1 with Comparative Example 3, the carrier of Comparative Example 3 (type A silica gel) was subjected to the same acid washing and high-temperature calcination treatment, but the average pore diameter after treatment was only 3.3 nm, and the catalyst had a lower butadiene selectivity. The average pore diameter of the carrier of Example 1 after treatment was 5.5 nm, and the catalyst had a higher butadiene selectivity. Therefore, a smaller carrier pore diameter (<4 nm) will reduce the butadiene selectivity.

[0102] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical concept of the present invention, the technical solution of the present invention may be subjected to a variety of simple modifications, including combining the specific technical features in any suitable manner. To avoid unnecessary repetition, the present invention will not further describe various possible combinations. However, these simple modifications and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A zirconium-containing catalyst, characterized in that The catalyst comprises a mesoporous silica support and zirconium oxide supported on the support, wherein the basic amount of the mesoporous silica support is 0.5-5 μmol / g and the average pore size of the mesoporous silica support is 4-10 nm; The mesoporous silica carrier is obtained by using mesoporous silica as a raw material, washing with acid, and then calcining at a temperature of 700-800° C. The average pore diameter of the mesoporous silica raw material is above 4 nm.

2. The catalyst according to claim 1, The mesoporous silica carrier is an amorphous mesoporous silica with random pores and a specific surface area of ​​300 m 2 / g; and / or When the mesoporous silica carrier carries a catalyst containing 1-6 wt% zirconium oxide, the catalyst has a basic base content of 2-18 μmol / g; and / or The specific surface area of ​​the catalyst is ≥300m 2 / g; average pore size ≥ 4nm; and / or The mass of the zirconium oxide is 1-6% of the mass of the mesoporous silica support.

3. The catalyst according to claim 2, wherein The specific surface area of ​​the mesoporous silica carrier is 320-550m 2 / g; and / or The specific surface area of ​​the catalyst is 300-550m 2 / g, and the average pore size is 4-10nm.

4. The catalyst according to any one of claims 1 to 3, wherein The preparation steps of the mesoporous silica carrier include: At a temperature of 50°C to 100°C, the mesoporous silica raw material is contacted with an acid solution with a concentration of 0.1M to 5M for acid washing for 1 hour to 8 hours. After the acid washing is completed, the raw material is washed with deionized water until it is neutral, filtered, and the solid is placed in a drying oven to dry, and then calcined in a muffle furnace at 700°C to 800°C.

5. The method for preparing the catalyst according to any one of claims 1 to 4, wherein The method includes: Mesoporous silica is used as raw material, which is acid-washed and then calcined at 700-800°C to obtain a mesoporous silica carrier; The precursor of elemental zirconium is deposited on the mesoporous silica carrier, dried and then calcined. The average pore diameter of the mesoporous silica raw material is above 4 nm.

6. The method according to claim 5, wherein: The pickling acid is one or more of nitric acid aqueous solution, hydrochloric acid and citric acid aqueous solution; and / or The concentration of pickling acid is 0.1M~5M; and / or The volume of the acid solution is 2-10 times the volume of the mesoporous silica raw material; and / or The pickling conditions include: temperature of 50°C to 100°C; time of 1 hour to 8 hours; and / or The specific surface area of ​​the mesoporous silica raw material is 300-660m 2 / g, the pore volume is 0.6-1.2mL / g, and the average pore diameter is 4-10nm.

7. The method according to claim 5 or 6, wherein: The method includes: ① The mesoporous silica raw material is contacted with at least one acid solution with a concentration of 0.1M to 5M at a temperature of 50°C to 100°C for a contact time of 1 hour to 8 hours. After the acid wash, the carrier is washed with deionized water until neutral, filtered, and the solid is placed in a drying oven to dry; ② calcining the solid obtained in step ① at 700°C to 800°C in a muffle furnace to obtain a carrier; ③ depositing the elemental zirconium precursor on the mesoporous silica support obtained in step ②; ④ The solid obtained from step ③ was placed in a drying oven for drying and finally calcined in a muffle furnace.

8. Use of the catalyst according to any one of claims 1 to 4 in the reaction of preparing butadiene from ethanol and acetaldehyde.

9. A method for preparing butadiene from ethanol and acetaldehyde, characterized in that: The method comprises: in a fixed bed reactor, passing a mixed solution of ethanol, acetaldehyde and water through a bed of a supported catalyst, wherein the supported catalyst is the catalyst according to any one of claims 1 to 4.

10. The method according to claim 9, wherein: The operating conditions in the fixed bed reactor include: a temperature of 300-400°C; and / or The pressure is atmospheric; and / or The raw material mass space velocity is 0.5-5h -1 .

11. The method according to claim 10, wherein: The temperature is 310-350°C; and / or The raw material mass space velocity is 0.8-3h -1 .

12. The method according to claim 11, wherein The molar ratio of ethanol to acetaldehyde in the raw material solution is 2:1-5:1, and the mass of water accounts for 5-50% of the mass of the total solution.

13. The method according to claim 12, wherein: The molar ratio of ethanol to acetaldehyde in the raw material solution is 2.5:1-4:1, and the mass of water accounts for 8-30% of the mass of the total solution.

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