A Ni-ReO x Preparation methods and applications of TiO2 bimetallic catalysts
By preparing a Ni-ReOx/TiO2 bimetallic catalyst, the harsh reaction conditions and separation problems in the production of 2-methylpropenol were solved, enabling continuous production and high selectivity, and reducing costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- DALIAN INSTITUTE OF CHEMICAL PHYSICS CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2022-08-24
- Publication Date
- 2026-06-05
AI Technical Summary
Existing 2-methylpropenol production processes suffer from harsh reaction conditions, difficulty in product separation, numerous byproducts, poor safety, and high equipment investment, and continuous production is difficult to achieve.
A Ni-ReOx/TiO2 bimetallic catalyst was prepared using ultrasound assistance. The catalyst was prepared through aging, drying, and calcination steps, and then selectively hydrogenated with methacrolein using hydrogen reduction in a fixed-bed reactor.
This method enables continuous production of 2-methylpropenol, reduces production costs, improves catalyst activity and selectivity, simplifies product separation, and allows the reaction to proceed under mild conditions.
Smart Images
Figure BDA0003813642730000101 
Figure BDA0003813642730000102 
Figure HDA0003813642740000011
Abstract
Description
Technical Field
[0001] This application relates to a Ni-ReO x The preparation method and application of / TiO2 bimetallic catalysts belong to the field of chemical engineering. Background Technology
[0002] 2-Methylpropenol is widely used in fine chemical production and can be used in the large-scale production of polymer monomers, surfactants, synthetic resin additives, and polycarboxylic acid superplasticizers.
[0003] Currently, industrial methods for preparing 2-methylpropenol can be categorized into four types based on their reaction mechanisms: 1. Chlor-alkali method, 2. Hydrogen transfer method, 3. Selective hydrogenation method, and 4. Dehydration method. The chlor-alkali method is currently the main method for large-scale production of 2-methylpropenol. This method involves the reaction of isobutylene with chlorine to generate isobutylene chloride, which can then undergo a hydroxyl substitution reaction under alkaline conditions to produce 2-methylpropenol. Although this process is widely used, the reaction conditions are relatively harsh, product separation and solvent recovery are difficult, and a large amount of ether byproducts are produced during the reaction, further increasing the difficulty of separation. Furthermore, the use of chlorine places higher demands on safety and equipment investment. To overcome the need for chlorine, researchers have used small-molecule alcohols as hydrogen donors to transfer hydrogen from the hydroxyl group of the alcohol to the carbonyl group. This method adapts to the coupling of dehydrogenation and hydrogenation and is also known as the hydrogen transfer method. US Patent 4731488 uses magnesium oxide as a catalyst for the production of methylpropenol; however, this reaction requires a high temperature. Chinese patent (CN106984356A) uses ethanol as a hydrogen donor; however, acetal is also generated as a byproduct. Besides the two methods mentioned above, the dehydration method utilizes a dehydrating agent with 2-methyl-1,3-propanediol as a raw material to produce 2-methylpropenal.
[0004] Compared to the three 2-methylpropenol production processes mentioned above, selective hydrogenation is a more environmentally friendly and efficient method. Although Chinese invention patent (CN102167657B) achieves highly selective preparation of 2-methylpropenol, this process, using a batch reactor, is difficult to scale up for continuous production, and the use of a series of solvents increases the difficulty of separation. Furthermore, Chinese invention patents (CN106631691A) and (CN107056566A) report a method for the continuous production of 2-methylpropenol using a noble metal catalyst. Summary of the Invention
[0005] This invention innovatively improves upon some shortcomings of existing technologies by designing an excellent catalyst preparation method and rationally designing and optimizing the reaction process. Ni-ReO with oxygen vacancies is prepared using an ultrasound-assisted preparation method. xA bimetallic catalyst was used for the selective hydrogenation of methacrolein, enabling the continuous production of 2-methylpropenol using hydrogen as a reducing agent and a fixed-bed reactor.
[0006] This application focuses on catalysts and optimizes the design and preparation methods of catalysts to achieve a better method.
[0007] Titanium dioxide (TiO2) possesses advantages such as being non-toxic, structurally stable, and inexpensive. In recent years, nano-TiO2 materials have been extensively studied in numerous fields, including coatings, daily chemicals, food colorings, and solar cells. The TiO2 in hydrogen-treated TiO2 contains Ti... 4+ It will be partially reduced to Ti 3+ This process involves partial coating of the active metal surface, a phenomenon known as the coating effect. The coating effect effectively prevents the sintering of active metal sites; the defects on the catalyst surface after partial reduction cause overflow, effectively enhancing the catalyst's hydrogenation activity. TiO2, due to the presence of Lewis acid sites on its surface, is generally considered a weakly acidic support. Some studies have shown that Lewis acid sites on TiO2 help reduce carbon deposition.
[0008] The TiO2-supported Ni-ReOx bimetallic catalyst involved in this application has good activity, high selectivity and strong stability, and has great potential industrial application value.
[0009] According to the first aspect of this application, a Ni-ReO is provided. x The preparation method of the / TiO2 bimetallic catalyst includes the following steps:
[0010] (1) A mixture containing nickel source and titanium source is aged, dried (I) and calcined (I) to obtain Ni / TiO2 precursor;
[0011] (2) The Ni / TiO2 precursor and the rhenium source compound were impregnated in equal volumes, and after drying (II) and calcination (II), Ni-ReO2 was obtained. x / TiO2 bimetallic catalyst.
[0012] Optionally, the nickel source is selected from at least one of nickel nitrate, nickel chloride, and nickel oxalate.
[0013] Optionally, the titanium source is selected from at least one of tetrabutyl titanate, titanium tert-butoxide, and metatitanic acid.
[0014] Optionally, the rhenium source is selected from at least one of ammonium perperurate, rhenium pentachloride, and rhenium fluoride.
[0015] Optionally, the Ni-ReO x In the TiO2 bimetallic catalyst, the nickel source is loaded with Ni-ReO.x The mass of the nickel source is 3-25 wt.% of the TiO2 bimetallic catalyst, and the mass of the nickel source is based on the mass of nickel element in the nickel source.
[0016] Optionally, the rhenium source is loaded with Ni-ReO. x The rhenium source comprises 15–50 wt.% of the TiO2 bimetallic catalyst, and the mass of the rhenium source is based on the mass of rhenium in the rhenium source.
[0017] Optionally, the Ni-ReO x In the TiO2 bimetallic catalyst, the atomic ratio of Ni atoms to Re atoms is 1:6 to 1:1.
[0018] Optionally, in step (1), the aging temperature is 30-90°C and the aging time is 24-48 hours.
[0019] Optionally, the temperature of drying I is 25–150°C, and the drying time is 24–48 h.
[0020] Optionally, the temperature of calcination I is 150–950°C, and the calcination time is 1–5 hours.
[0021] Optionally, in step (1), the aging temperature is selected from any value among 30℃, 60℃, 80℃, and 90℃, or a range between any two of the above points.
[0022] Optionally, the aging time is selected from any value among 24h, 36h, 40h, and 48h, or a range between any two of the above points.
[0023] Optionally, the temperature of the drying I is selected from any value of 25°C, 50°C, 75°C, 100°C, 125°C, or 150°C, or a range between any two of the above.
[0024] Optionally, the drying time I is selected from any value among 24h, 36h, 40h, and 48h, or a range between any two of the above points.
[0025] Optionally, the temperature of the roasting I is selected from any value of 150℃, 200℃, 300℃, 400℃, 500℃, 800℃, 900℃, 950℃ or a range between any two of the above points.
[0026] Optionally, the roasting time I is selected from any value among 1h, 2h, 3h, 4h, and 5h, or a range between any two of the above points.
[0027] Optionally, in step (2), the temperature of drying II is 25-150°C, and the drying time is 24-48h.
[0028] Optionally, the temperature of the second calcination is 150–950°C, and the calcination time is 1–5 hours.
[0029] Optionally, in step (2), the temperature of drying II is selected from any value of 25°C, 50°C, 100°C, 125°C, 150°C or a range between any two of the above points.
[0030] Optionally, the drying time II is selected from any value among 24h, 36h, 40h, and 48h, or a range between any two of the above points.
[0031] Optionally, the temperature of the roasting II is selected from any value of 150℃, 200℃, 300℃, 400℃, 500℃, 800℃, 900℃, 950℃ or a range between any two of the above points.
[0032] Optionally, the roasting time II is selected from any value among 1h, 2h, 3h, and 5h, or a range between any two of the above points.
[0033] Optionally, the atmospheres for calcination I and calcination II are independently selected from at least one of nitrogen atmosphere, air atmosphere, and carbon dioxide atmosphere.
[0034] According to a second aspect of this application, Ni-ReO prepared by the preparation method described above is provided. x Application of at least one of the / TiO2 bimetallic catalysts in the selective hydrogenation of methacrolein to 2-methylpropenol.
[0035] Optionally, Ni-ReO x The TiO2 bimetallic catalyst is first pre-reduced under a reducing atmosphere, and then reacted with methacrolein and hydrogen to produce 2-methylpropenol.
[0036] Optionally, the reducing atmosphere is selected from hydrogen and / or carbon monoxide.
[0037] Optionally, the pre-reduction time is 2 to 3 hours, and the pre-reduction temperature is 300 to 800°C.
[0038] Optionally, the pre-restore time is selected from any value among 2h, 2.5h, and 3h, or a range between any two of the above points.
[0039] Optionally, the pre-reduction temperature is selected from any value of 300℃, 400℃, 500℃, 600℃, 700℃, 800℃ or a range between any two of the above points.
[0040] Optionally, the molar ratio of hydrogen to methacrolein is 1:1 to 20:1.
[0041] Optionally, the mass hourly space velocity (HHSV) of the methacrolein is 0.5–5 h⁻¹. -1 .
[0042] Optionally, the reaction pressure is 0.1 to 5 MPa.
[0043] Optionally, the reaction temperature is 50–250°C;
[0044] Optionally, the molar ratio of hydrogen to methacrolein is selected from any value among 1:1, 5:1, 10:1, 15:1, 20:1, or a range between any two of the above.
[0045] Optionally, the mass hourly space velocity (MSV) of the methacrolein is selected from 0.5 h⁻¹. -1 1h -1 2h -1 3h -1 4h -1 5h -1 Any value in the range or any two points mentioned above.
[0046] The first solution adopted in this invention is:
[0047] (1) One or two of nickel nitrate and nickel chloride are dissolved in 100 ml of deionized water, and the mass of the metal salt is calculated based on the loading of 3 to 25 wt.%.
[0048] (2) Place the above solution in a three-necked flask and place it in an instrument with ultrasonic heating function to maintain a constant temperature of 25-95°C and continuously perform ultrasonic treatment.
[0049] (3) Dissolve an appropriate amount of tetrabutyl titanate in one or more of methanol, ethanol, ethylene glycol, and acetone, mix them evenly, and then slowly add them dropwise to the metal salt solution at a rate of 0.1 to 3 ml / min.
[0050] (4) The above samples were aged at 60°C for 24 hours.
[0051] (5) After filtration, dry at 25-150℃ for 24 hours.
[0052] (6) The catalyst is calcined in one or more of nitrogen, argon, air or oxygen at a temperature between 150 and 950°C.
[0053] (7) Prepare an aqueous solution of ammonium perrhenate and immerse it in the above sample. The Ni / Re atomic ratio is between 1 / 8 and 1 / 1.
[0054] (8) After calcination, the catalyst is shaped and then in-situ reduced in a fixed-bed reactor using hydrogen at a temperature of 300–750°C.
[0055] (9) The reaction temperature is between 50 and 250°C, and the space velocity is between 0.5 and 5 h⁻¹. -1 The ratio of hydrogen to methacrolein is between 1 and 20.
[0056] The second solution adopted in this invention:
[0057] (1) One or two of nickel nitrate and nickel chloride and a certain mass of tetrabutyl titanate are dissolved in 100 ml of one or more alcohols of methanol, ethanol, ethylene glycol and acetone, wherein the mass of the metal salt is calculated based on the loading amount between 3 and 25 wt.%.
[0058] (2) Place the above solution in a three-necked flask and place it in an instrument with ultrasonic heating function to maintain a constant temperature of 25-95°C and continuously perform ultrasonic treatment.
[0059] (3) Slowly add deionized water to the above solution at a rate of 0.1 to 3 ml / min.
[0060] (4) The above samples were aged at 60-90℃ for 24 hours.
[0061] (5) After filtration, dry at 25-150℃ for 24 hours.
[0062] (6) The catalyst is calcined in one or more of nitrogen, argon, air or oxygen at a temperature between 150 and 950°C.
[0063] (7) Prepare an aqueous solution of ammonium perrhenate and immerse it in the above sample. The Ni / Re atomic ratio is between 1 / 8 and 1 / 1.
[0064] (8) Reduce the above sample in a hydrogen atmosphere at a temperature of 100 to 800°C.
[0065] (9) After the reduced sample is cooled to room temperature, one or more of air, nitrogen, oxygen and carbon dioxide are introduced to passivate the catalyst.
[0066] (10) The reaction temperature is between 50 and 250°C, and the space velocity is between 0.5 and 5 h⁻¹. -1 The ratio of hydrogen to methacrolein is between 1 and 20.
[0067] The third solution adopted in this invention:
[0068] (1) One or two of nickel nitrate and nickel chloride and a certain mass of tetrabutyl titanate are dissolved in 100 ml of one or more alcohols of methanol, ethanol, ethylene glycol and acetone, wherein the mass of the metal salt is calculated based on the loading amount between 3 and 25 wt.%.
[0069] (2) Place the above solution in a three-necked flask and place it in an instrument with ultrasonic heating function to maintain a constant temperature of 25-95°C and continuously perform ultrasonic treatment.
[0070] (3) Prepare a urea solution and slowly inject it into the above solution at a dripping rate of 0.1 to 3 ml / min.
[0071] (4) The temperature of the mixed solution was slowly increased to between 40 and 90°C at a heating rate of 1°C / min and maintained for 2 hours.
[0072] (5) The above samples were aged at room temperature for 24 hours.
[0073] (6) After centrifugation and filtration, wash three times with deionized water.
[0074] (7) The catalyst is calcined in one or more of nitrogen, argon, air or oxygen at a temperature between 150 and 950°C.
[0075] (8) Prepare an aqueous solution of an appropriate amount of ammonium perrhenate and load Re onto the catalyst by excess impregnation. The Ni / Re atomic ratio is between 1 / 8 and 1 / 1.
[0076] (9) After impregnation, the sample was left to stand at room temperature for 24 hours and then dried at 60-150℃ for 24 hours.
[0077] (10) The catalyst is calcined in one or more of nitrogen, argon, air or oxygen at a temperature between 150 and 950°C.
[0078] (11) After calcination, the catalyst is shaped and then in-situ reduced in a fixed-bed reactor using hydrogen at a temperature of 300–750°C.
[0079] (12) The reaction temperature is between 50 and 250°C, and the space velocity is between 0.5 and 5 h⁻¹. -1 The ratio of hydrogen to methacrolein is between 1 and 20.
[0080] The beneficial effects that this application can produce include:
[0081] Ni-ReO x / TiO2 bimetallic catalysts are relatively inexpensive to prepare, exhibit high reactivity and selectivity for target products, and possess extremely strong stability; they are produced using a continuous reactor, with the reaction carried out under solvent-free and relatively mild reaction conditions; and the heterogeneous catalyst facilitates separation from the product.
[0082] After treatment with hydrogen atmosphere, the strong interaction between metallic Ni and the supported TiO2 creates a coating effect that enhances the stability of the active sites. Simultaneously, the generated oxygen vacancies facilitate the adsorption of O atoms on carbonyl functional groups, effectively lowering the hydrogenation activation energy of the C=O double bond. Metallic Re, acting as a promoter, modifies the geometric and electronic structure of metallic Ni, improving selectivity and catalyst activity. Furthermore, the use of non-noble metal Ni to replace noble metals Pt and Pd effectively reduces the catalyst's production cost. Adaptation with a continuous reactor-fixed bed significantly improves the production efficiency of 2-methylpropenol. Under solvent-free conditions with hydrogen as the reducing agent, the Ni-Re bimetallic catalyst achieves a 98% conversion rate of methacrolein and a 90% selectivity for 2-methylpropenol, while maintaining stable operation over a relatively long period. Attached Figure Description
[0083] Figure 1 The XRD pattern of the catalyst used in Example 3 is shown in this application.
[0084] Figure 2 Raman spectra of catalysts with different Ni / Re atomic ratios in this application
[0085] (a represents an unreduced Ni / Re atomic ratio of 1:1, b represents an unreduced Ni / Re atomic ratio of 1:3, c represents a reduced Ni / Re atomic ratio of 1:1, d represents a reduced Ni / Re atomic ratio of 1:2, and e represents a reduced Ni / Re atomic ratio of 1:3). Detailed Implementation
[0086] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.
[0087] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.
[0088] In the embodiments of this application, the reduced catalyst was characterized by XRD using a Bruck D8 Focus instrument; and the unreduced and reduced catalysts were characterized by Raman spectroscopy using a Thermo Fisher Raman spectral source with a wavelength of 532 nm.
[0089] Conversion rate = 1 - Amount of unconverted reactants / Total amount of reactants.
[0090] Selectivity = Amount of product / Amount of reactants converted.
[0091] Example 1
[0092] 10g of nickel nitrate was dissolved in 100mL of deionized water and transferred to a three-necked flask. The flask was then placed in a constant-temperature bath with ultrasonic heating and continuously sonicated at a constant temperature of 30℃. 21g of tetrabutyl titanate was dissolved in a mixed solution of ethanol and acetone. The tetrabutyl titanate solution was added dropwise to the metal ion solution at a rate of 1mL / min using a constant-flow pump. After the addition was complete, the sample was aged at 60℃ for 24h. The aged sample was filtered and dried at 150℃ for 24h. The dried catalyst was calcined in air at 700℃. 0.5g of ammonium perrhenate was dissolved in 10mL of deionized water and impregnated onto the calcined catalyst. The catalyst was dried at 25℃ for 24h, then at 120℃ for 24h, and finally calcined at 200℃ in air. The calcined catalyst was pressed into tablets, crushed into 20-40 mesh, and placed in a fixed-bed reactor for reduction with hydrogen at 400℃ for 2h. After the fixed-bed reactor is cooled to 180°C, methacrolein is introduced at a space velocity of 2 h⁻¹. -1 The ratio of hydrogen to methacrolein is 10.
[0093] Example 2
[0094] 10g of nickel nitrate and 21g of tetrabutyl titanate were dissolved in 100mL of ethanol and acetone solution. The solution was transferred to a three-necked flask and placed in an instrument with ultrasonic heating function at a constant temperature of 30℃ and sonicated. Deionized water was slowly added dropwise to the solution at a rate of 0.5mL / min. The sample was aged at 60℃ for 24h, filtered, and dried at 150℃ for 24h. The sample was calcined at 600℃ in air for 2h. 0.5g of ammonium perrhenate was dissolved in 10mL of deionized water and impregnated onto the calcined catalyst. The sample was dried at 25℃ for 24h, then at 120℃ for 24h, and calcined at 200℃ in air. The calcined sample was reduced at 400℃ in hydrogen atmosphere for 2h. After the sample cooled to room temperature, carbon dioxide was introduced to passivate the catalyst. The reduced catalyst was pressed into tablets, crushed into 20-40 mesh, and loaded into a fixed-bed reactor for pre-reduction with hydrogen at 300°C for 2 hours. After the fixed-bed reactor cooled to 180°C, methacrolein was introduced at a space velocity of 2 h⁻¹. -1 The ratio of hydrogen to methacrolein is 10.
[0095] Example 3
[0096] 10g of nickel nitrate and 21g of tetrabutyl titanate were dissolved in 100mL of ethanol and acetone solution. The solution was transferred to a three-necked flask and placed in an instrument with ultrasonic heating function at a constant temperature of 30℃, where it was continuously sonicated. 5g of urea was dissolved in 100mL of water, and the urea solution was slowly added dropwise to the ethanol solution at a rate of 1mL / min. After the urea solution was added, the temperature was increased to 80℃ at a rate of 1℃ / min and maintained for 2h. The sample was aged for 24h. After filtration, it was washed three times with deionized water. The catalyst was calcined in air at 500℃. 0.5g of ammonium perrhenate was dissolved in 10mL of deionized water and impregnated onto the calcined catalyst. It was dried at 25℃ for 24h, dried at 120℃ for 24h, and calcined in air at 200℃. The calcined catalyst was ground, pressed into tablets, and crushed to 20 to 40 mesh. The shaped catalyst was loaded into a fixed-bed reactor, and hydrogen was used to reduce the catalyst at 200°C. After the fixed-bed reactor cooled to 180°C, methacrolein was introduced at a space velocity of 2 h⁻¹. -1 The ratio of hydrogen to methacrolein is 10. Figure 1 The image shows the XRD pattern of the catalyst used in Example 3 of this application. It can be seen that the metallic Ni is in a highly dispersed state.
[0097] Example 4
[0098] 10g of nickel nitrate and 21g of tetrabutyl titanate were dissolved in 100mL of ethanol and acetone solution. The solution was transferred to a three-necked flask and placed in an instrument with ultrasonic heating function at a constant temperature of 30℃, where it was continuously sonicated. 5g of urea was dissolved in 100mL of water, and the urea solution was slowly added dropwise to the ethanol solution at a rate of 1mL / min. After the urea solution was added, the temperature was increased to 80℃ at a rate of 1℃ / min and maintained for 2h. The sample was aged for 24h. After filtration, it was washed three times with deionized water. The catalyst was calcined in air at 500℃. 0.5g of ammonium perrhenate was dissolved in 10mL of deionized water and impregnated onto the calcined catalyst. It was dried at 25℃ for 24h, dried at 120℃ for 24h, and calcined in air at 200℃. The calcined catalyst was ground, pressed into tablets, and crushed to 20 to 40 mesh. The shaped catalyst was loaded into a fixed-bed reactor, and hydrogen was used to reduce the catalyst at 200°C. After the fixed-bed reactor cooled to 180°C, methacrolein was introduced at a space velocity of 2 h⁻¹. -1 The ratio of hydrogen to methacrolein is 10.
[0099] Following the steps described above, ammonium perrhenate was added in sequential amounts of 0.1 g, 0.18 g, 0.21 g, and 0.25 g to prepare catalysts with Ni / Re atomic ratios of 1:1, 1:2, 1:3, and 1:4, respectively. These catalysts were then used for the selective hydrogenation of methacrolein. The specific selectivity of methacrolein is shown in Table 2. According to the data in Table 2, reducing the Ni / Re atomic ratio can promote the selectivity of unsaturated enols.
[0100] Figure 2 The Raman spectra of the catalysts with different Ni / Re atomic ratios in this application are shown (a is unreduced Ni / Re atomic ratio 1:1, b is unreduced Ni / Re atomic ratio 1:3, c is reduced Ni / Re atomic ratio 1:1, d is reduced Ni / Re atomic ratio 1:2, and e is reduced Ni / Re atomic ratio 1:3). This shows that Ni is subjected to strong forces and achieves a high degree of dispersion.
[0101] Comparative Example
[0102] Weigh 5g of TiO2 support, and dissolve 3g of nickel nitrate hexahydrate and 0.5g of ammonium perrhenate in 5g of deionized water. Then, impregnate the TiO2 support with the metal salt solution and let it stand at 25℃ for 24h, followed by drying at 120℃ for 24h, and finally calcining at 400℃ in air for 2h. The calcined catalyst is then ground, pressed into tablets, and crushed to 20-40 mesh. The formed catalyst is loaded into a fixed-bed reactor, and reduced using hydrogen at 200℃. After the fixed-bed reactor cools to 180℃, methacrolein is introduced at a space velocity of 2h⁻¹. -1 The ratio of hydrogen to methacrolein is 10.
[0103] Table 1 shows the activity evaluation results in the examples.
[0104]
[0105] Table 2. Effect of Ni / Re atomic ratio on the results of Example 4.
[0106]
[0107] As can be seen from Table 1, Example 3 exhibits good activity and selectivity for the target product in the specific preparation method described above.
[0108] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.
Claims
1. An application of selective hydrogenation of methacrolein to prepare 2-methylpropenol, characterized in that, Ni-ReO x The TiO2 bimetallic catalyst is first pre-reduced under a reducing atmosphere, and then contacted with methacrolein and hydrogen to react under solvent-free conditions to produce 2-methylpropenol. The pre-reduction time is 2 h to 3 h, and the pre-reduction temperature is 300 to 800 ℃. Ni-ReO with oxygen vacancies was prepared using an ultrasound-assisted preparation method. x Bimetallic catalysts; Ni-ReO x The preparation method of the / TiO2 bimetallic catalyst includes the following steps: (1) A mixture containing nickel source and titanium source was obtained under ultrasonic heating assistance, and after aging, drying I and calcination I, Ni / TiO2 precursor was obtained; (2) Ni / TiO2 precursor and rhenium source compound were impregnated in equal volumes, and after drying (II) and calcination (II), Ni-ReO was obtained. x / TiO2 bimetallic catalyst; The titanium source is selected from at least one of tetrabutyl titanate, titanium tert-butoxide, and metatitanic acid. The Ni-ReO x / TiO2 bimetallic catalyst The nickel source is loaded with Ni-ReO. x / 3-25 wt.% of the TiO2 bimetallic catalyst, wherein the mass of the nickel source is based on the mass of nickel element in the nickel source; The rhenium source is loaded with Ni-ReO. x The rhenium source comprises 15-50 wt.% of the TiO2 bimetallic catalyst, and the mass of the rhenium source is based on the mass of rhenium element in the rhenium source. The Ni-ReO x In the TiO2 bimetallic catalyst, the atomic ratio of Ni atoms to Re atoms is 1:6 to 1:
1.
2. The application according to claim 1, characterized in that, The nickel source is selected from at least one of nickel nitrate, nickel chloride, and nickel oxalate; The rhenium source is selected from at least one of ammonium perperurate, rhenium pentachloride, and rhenium fluoride.
3. The application according to claim 1, characterized in that, In step (1), the aging temperature is 30~90℃ and the aging time is 24~48 h; The temperature of drying I is 25–150 °C, and the drying time is 24–48 h. The temperature of calcination I is 150–950 °C, and the calcination time is 1–5 h.
4. The application according to claim 1, characterized in that, In step (2), the temperature of drying II is 25-150 °C, and the drying time is 24-48 h. The temperature of the second calcination is 150–950 °C, and the calcination time is 1–5 h.
5. The application according to claim 1, characterized in that, The atmospheres for roasting I and roasting II are independently selected from at least one of nitrogen atmosphere, air atmosphere, and carbon dioxide atmosphere.
6. The application according to claim 1, characterized in that, The reducing atmosphere is selected from hydrogen and / or carbon monoxide.
7. The application according to claim 1, characterized in that, The molar ratio of hydrogen to methacrolein is 1:1 to 20:1; The mass hourly space velocity (MSV) of the methacrolein is 0.5–5 h⁻¹. -1 ; The reaction pressure is 0.1~5.0 MPa; The reaction temperature is 50–250 °C.