Preparation method and application of a dual-oxide supported metal catalyst

Abstract

The application discloses a preparation method and application of a binary oxide supported metal catalyst, and the preparation method comprises the following steps: mixing a metal salt solution, an organic ligand and an additive, or mixing a metal salt solution and an alkali solution, aging, drying and calcining to obtain the binary oxide supported metal catalyst; the metal salt solution is selected from at least two of magnesium nitrate, chromium nitrate, manganese nitrate, iron nitrate, cobalt nitrate, nickel nitrate, copper nitrate, zinc nitrate, gallium nitrate, silver nitrate, indium nitrate and stannous chloride. The application is matched with a continuous reactor-fixed bed, and the production efficiency of 2-methylpropenol is greatly improved. Under the condition that hydrogen is used as a reducing agent and without a solvent, the conversion rate of methylpropenal on the catalyst reaches 83%, the selectivity of 2-methylpropenol is 90%, and the catalyst can be stably operated for a long time.

Description

Technical Field

[0001] This application relates to a method for preparing and applying a binary oxide-supported metal catalyst, belonging to the field of chemical technology. Background Technology

[0002] 2-Methylpropenol is an important raw material for the preparation of polycarboxylate superplasticizers. With the improvement of national infrastructure construction, the demand for polycarboxylate superplasticizers is increasing year by year.

[0003] Currently, 2-methylpropenol is mainly produced industrially via the chlor-alkali process. To overcome the safety concerns arising from the large-scale use of chlorine and to reduce the cost and difficulty of product separation, a direct hydrogenation method can not only solve these problems but also effectively utilize C4 isobutylene, a byproduct of petrochemical and coal chemical processes. Therefore, we have developed a binary metal oxide supported metal catalyst for the preparation of 2-methylpropenol. Summary of the Invention

[0004] By optimizing catalyst design and improving existing production processes, suitable catalysts were prepared. The use of solvents was eliminated, resulting in reduced production costs and increased capacity, achieving optimal process and system compatibility.

[0005] This application focuses on catalysts and optimizes the design and preparation methods of catalysts to achieve a better method.

[0006] Binary metal oxides possess a unique electronic structure, and the structural dislocations generated by lattice distortion facilitate electron conduction and reactant adsorption. This type of catalyst, or catalyst support, is widely used in chemical production processes.

[0007] The binary oxide-supported metal catalysts involved in this application have good activity, high selectivity and strong stability, and have great potential industrial application value.

[0008] According to one aspect of this application, a method for preparing a binary oxide-supported metal catalyst is provided, the method comprising:

[0009] The binary oxide supported metal catalyst is obtained by aging, drying, and calcining a mixture containing a metal salt solution, an organic ligand, and an additive, or a mixture containing a metal salt solution and an alkaline solution.

[0010] The metal salt solution is selected from at least two of the following: magnesium nitrate, chromium nitrate, manganese nitrate, ferric nitrate, cobalt nitrate, nickel nitrate, copper nitrate, zinc nitrate, gallium nitrate, silver nitrate, indium nitrate, and stannous chloride.

[0011] Optionally, the organic ligand is selected from citric acid and / or tannic acid.

[0012] Optionally, the additive is selected from polyethylene glycol and / or ethylene glycol.

[0013] Optionally, the mass ratio of the metal salt solution to the organic ligand is 1:10 to 1:50;

[0014] The mass of the metal salt solution is calculated based on its own mass, and the mass of the organic ligand is calculated based on its own mass.

[0015] Optionally, the mass ratio of the metal salt solution to the additive is 1:10 to 1:50;

[0016] The mass of the metal salt solution is calculated based on its own mass, and the mass of the auxiliary agent is calculated based on its own mass.

[0017] Optionally, the concentration of the metal salt solution is 0.1M to 1M, based on the mass of the metal salt.

[0018] Optionally, the aging temperature is 40–90°C, and the aging time is 4–12 hours.

[0019] Optionally, the aging temperature is selected from any value of 40℃, 50℃, 60℃, 70℃, 90℃ or a range between any two of the above points.

[0020] Optionally, the aging time is selected from any value of 4h, 6h, 8h, 10h, 12h or a range between any two of the above points.

[0021] Optionally, the drying temperature is 25–150°C, and the drying time is 24–48 hours.

[0022] Optionally, the drying temperature 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.

[0023] Optionally, the drying time is selected from any value among 24h, 30h, 36h, 40h, and 48h, or a range between any two of the above.

[0024] Optionally, the calcination temperature is 150–950°C, and the calcination time is 1–5 hours.

[0025] Optionally, the roasting temperature is selected from any value of 150℃, 200℃, 300℃, 400℃, 500℃, 700℃, 900℃, 950℃ or a range between any two of the above points.

[0026] Optionally, the roasting time is selected from any value of 1h, 2h, 3h, 4h, 5h or a range between any two of the above points.

[0027] Optionally, the alkaline solution comprises sodium hydroxide and sodium carbonate, wherein the molar ratio of sodium hydroxide to sodium carbonate is 10:1 to 1:10.

[0028] Optionally, the concentration of the alkaline solution is 0.1 to 1.5 M.

[0029] Optionally, the roasting atmosphere is selected from a nitrogen atmosphere and / or an air atmosphere.

[0030] According to another aspect of this application, a method for preparing 2-methylpropenol is provided, the method comprising: pre-reducing a catalyst, then contacting it with methacrolein and hydrogen to react and generate 2-methylpropenol;

[0031] The catalyst is selected from the binary metal oxide supported metal catalyst prepared by the preparation method described above.

[0032] Optionally, the mass hourly space velocity (HHSV) of the methacrolein is 0.5–5 h⁻¹. -1 .

[0033] Optionally, the mass hourly space velocity (MSV) of the methacrolein is selected from 0.5 h⁻¹. -1 1h -1 2h -1 3h -1 5h -1 Any value in the range or any two points mentioned above.

[0034] Optionally, the reaction temperature is 50–250°C.

[0035] Optionally, the reaction pressure is 0.1 to 5.0 MPa.

[0036] Optionally, the molar ratio of hydrogen to methacrolein is 1:1 to 20:1.

[0037] 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.

[0038] Optionally, the pre-reduction atmosphere is selected from at least one of hydrogen atmosphere, carbon dioxide atmosphere, and air atmosphere.

[0039] Optionally, the pre-reduction temperature is 300–800°C, and the pre-reduction time is 2–3 hours.

[0040] Optionally, the pre-reduction temperature is selected from any value of 300℃, 400℃, 500℃, 700℃, 800℃ or a range between any two of the above points.

[0041] Optionally, the pre-restore time is any value among 2h, 2.5h, and 3h, or a range between any two of the above points.

[0042] As a specific implementation method, this application is achieved through the following technical solution:

[0043] The first solution adopted in this invention:

[0044] (1) Dissolve at least one of lanthanum nitrate, nickel nitrate, cerium nitrate, cobalt nitrate, indium nitrate, ferric nitrate, and magnesium nitrate in deionized water, with the concentration of the solution between 0.1 and 1.5 M.

[0045] (2) Add a certain amount of citric acid and poloxamer F127 to the above solution. The amount of citric acid is 1 to 3 times that of the metal cations in the solution. In addition, add a certain amount of polyethylene glycol-400 to the solution. The amount of polyethylene glycol-400 is 0.1 times that of citric acid.

[0046] (3) Stir the above solution vigorously at 25°C for 2 hours.

[0047] (4) Heat the above solution to between 40 and 90°C for 4 to 12 hours.

[0048] (5) The sample was dried at 25-150℃ for 24-48 hours.

[0049] (6) The sample is roasted in a nitrogen or air atmosphere at a temperature between 150 and 950°C for a time between 1 and 5 hours.

[0050] (7) The calcined catalyst is pressed into tablets and crushed into particles of 20 to 40 mesh, and then loaded into a fixed-bed reactor to reduce the catalyst in situ using hydrogen in the range of 300 to 750°C.

[0051] (8) 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.

[0052] The second solution adopted in this invention:

[0053] (1) Prepare an aqueous solution A from at least one of magnesium nitrate, aluminum nitrate, nickel nitrate, ferric nitrate, copper nitrate, indium nitrate, gallium nitrate, stannous chloride, chloroplatinic acid, and ammonium perrhenate, with a concentration between 0.1 and 1.5 M.

[0054] (2) Dissolve sodium hydroxide and sodium carbonate in deionized water to prepare solution B. The concentration of the solution is between 0.1 and 1.5 M. The molar ratio of sodium hydroxide to sodium carbonate in the solution is between 10:1 and 1:10.

[0055] (3) Stir solution A vigorously at 25°C, while adding solution B and its slow addition at a rate of 0.1 to 5 ml / min.

[0056] (4) When the pH of the mixed solution is 9, stop adding solution A and age it for 24-48 hours.

[0057] (5) Filter the above sample and dry it at 25-150℃ for 24-48h.

[0058] (6) After drying, the sample is pressed into tablets and crushed into particles of 20 to 40 mesh. The tablets are then loaded into a fixed-bed reactor and hydrogen is used to reduce the catalyst in situ within the range of 300 to 750°C.

[0059] (11) 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.

[0060] The third solution adopted in this invention:

[0061] (1) Prepare an aqueous solution A with a concentration of 0.1 to 0.9 M using one or more of sodium hydroxide, sodium carbonate, sodium bicarbonate, and ammonia water, and add 0.5 g of CTAB and / or poloxamer F127 to it.

[0062] (2) Dissolve at least one of magnesium nitrate, aluminum nitrate, cerium nitrate, nickel nitrate, and lanthanum nitrate in an aqueous solution to prepare solution B, with a concentration between 0.1 and 0.9 M.

[0063] (3) Stir solution B vigorously at 25℃, while slowly adding solution A to solution B at a rate of 0.1 to 5 ml / min.

[0064] (4) Stop adding solution A when the pH of the above mixed solution reaches a point between 8 and 14. Aging at 25°C for 24 hours.

[0065] (5) Filter the aged sample and then dry it at 25-150℃ for 24-48h.

[0066] (6) The sample is roasted in either nitrogen or air at a temperature between 150 and 950°C for a time between 1 and 5 hours.

[0067] (7) Dissolve at least one or more of nickel nitrate, copper nitrate, cobalt nitrate, magnesium nitrate, ruthenium trichloride, chloroplatinic acid, ammonium molybdate, and ammonium tungstate in water to form an aqueous solution. The volume of the solution is matched according to the water absorption rate of the calcined sample. The loading of the catalytically active metal is between 3 and 25 wt.%, and the ratio of the number of catalytically active metal atoms to the atoms of other metals is between 10:1 and 1:10.

[0068] (8) The above sample was left to stand at 25°C for 24 hours, then dried at 25-150°C for 24-48 hours, and then calcined at 150-950°C for 1-5 hours.

[0069] (9) The calcined catalyst is pressed into tablets and crushed into 20-40 mesh particles, and then loaded into a fixed bed reactor to reduce the catalyst in situ using hydrogen in the range of 300-750°C.

[0070] (8) 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.

[0071] The present invention adopts the fourth solution:

[0072] (1) Dissolve several of the following in deionized water: magnesium nitrate, aluminum nitrate, cerium nitrate, nickel nitrate, lanthanum nitrate, iron nitrate, cobalt nitrate, stannous chloride, zinc nitrate, silver nitrate, ruthenium trichloride, and copper nitrate. The concentration of the solution is between 0.1 and 0.9 M.

[0073] (2) Add a certain amount of a mixture of citric acid and poloxamer F127 to the above solution. The amount of citric acid is 0.5 to 6 times the amount of the metal cation, and the amount of poloxamer is 0.1 to 1 times the amount of citric acid.

[0074] (3) Stir the above solution vigorously at 25°C for 2 hours.

[0075] (4) Heat the above solution to a temperature of 60-90°C and evaporate for 5-12 hours.

[0076] (5) Dry the evaporated sample at 25-150℃ for 24-48h.

[0077] (6) The sample is roasted in either nitrogen or air at a temperature between 150 and 950°C for a time between 1 and 5 hours.

[0078] (7) The calcined catalyst is pressed into tablets and crushed into 20-40 mesh particles, and then loaded into a fixed bed reactor to reduce the catalyst in situ using hydrogen in the range of 300-750°C.

[0079] (8) 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] The binary metal oxide supported metal catalyst disclosed in this application possesses unique electronic properties that can be used to adjust the electronic properties of the metal active sites, selectively hydrogenating the C=O double bond. The reaction is carried out under solvent-free conditions, effectively reducing separation energy consumption and increasing product profitability. This application significantly improves the production efficiency of 2-methylpropenol by adapting it to a continuous reactor-fixed bed. Under solvent-free conditions with hydrogen as the reducing agent, the conversion rate of methacrolein on the catalyst reaches 83%, and the selectivity of 2-methylpropenol is 90%, while the catalyst can operate stably for a relatively long period of time. Attached Figure Description

[0082] Figure 1 The above are X-ray photoelectron spectra of oxygen in Examples 1-3 of this application. Detailed Implementation

[0083] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0084] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0085] Conversion rate = 1 - Amount of unconverted reactants / Total amount of reactants.

[0086] Selectivity = Amount of product / Amount of reactants converted.

[0087] The binary metal oxidation was characterized using a Thermo Scientific ESCALAB 250Xi.

[0088] Example 1

[0089] 5g of lanthanum nitrate hexahydrate, 8g of nickel nitrate hexahydrate, 2g of cerium nitrate, and 1g of copper nitrate were dissolved in 40ml of deionized water. Simultaneously, 5g of citric acid, 2g of polyethylene glycol-400, and 3g of poloxamer F127 were added to the solution. The solution was vigorously stirred and kept at 25°C for 2 hours. The temperature was then raised to 60°C and maintained for 10 hours. The sample was dried at 100°C for 24 hours. The dried sample was calcined at 800°C for 2 hours. The calcined catalyst was tableted, crushed into 20-40 mesh particles, and loaded into a fixed-bed reactor for in-situ reduction of the catalyst using hydrogen at 750°C. After the reactor cooled to 200°C, the reactant methacrolein was introduced at a space velocity of 2 h⁻¹.-1 The hydrogen flow rate was 40 ml / min, and the selectivity of methylpropenol is shown in Table 1.

[0090] Example 2

[0091] Dissolve 3g magnesium nitrate, 3g aluminum nitrate, 1g nickel nitrate, 0.2g ferric nitrate, and 0.1g copper nitrate in 100ml deionized water to form solution A. Dissolve 5g sodium hydroxide and 10g sodium carbonate in 100ml deionized water to form solution B. Slowly inject solution B into solution A at 2ml / min using a constant flow pump at 25℃. Monitor the pH of the solution in real time. When the pH of the mixed solution reaches 9, stop adding solution A and age the sample for 24 hours. Wash, filter, and dry the aged sample at 100℃ for 24 hours. Press the dried catalyst into tablets, crush them into 20-40 mesh particles, and load them into a fixed-bed reactor. Reduce the catalyst in situ using hydrogen at 750℃. After the reactor cools to 200℃, introduce the reactant methacrolein at a space velocity of 2h⁻¹. -1 The hydrogen flow rate was 40 ml / min, and the selectivity of methylpropenol is shown in Table 1.

[0092] Example 3

[0093] Solution A is prepared by dissolving 5g sodium hydroxide, 10g sodium carbonate, and 0.5g poloxamer F127 in 100ml deionized water. Solution B is prepared by dissolving 10g aluminum nitrate, 10g nickel nitrate, and 2g lanthanum nitrate in 100ml deionized water. Solution B is stirred vigorously at 25°C, and solution A is slowly added to solution B at a rate of 2ml / min. The addition of solution A is stopped when the pH of the above solutions reaches 10. The sample is aged at 25°C for 24 hours, and then dried at 150°C for 24 hours. The dried sample is calcined at 800°C for 2 hours in an air atmosphere. Based on the water absorption rate, 0.1g ruthenium trichloride and 0.5g ammonium molybdate are dissolved in 4ml deionized water and impregnated into the calcined sample. The sample is allowed to stand at 25°C for 24 hours, then dried at 150°C for 24 hours, and finally calcined at 500°C for 2 hours. The dried catalyst was compressed into tablets and crushed into 20-40 mesh particles, then loaded into a fixed-bed reactor for in-situ reduction using hydrogen at 750°C. After the reactor cooled to 200°C, the reactant methacrolein was introduced at a space velocity of 2 h⁻¹. -1 The hydrogen flow rate was 40 ml / min. The selectivity of methylpropenol is shown in Table 1. From Figure 1 It can be seen that there are oxygen vacancies in binary metal oxides, which can form carbonyl-loving sites.

[0094] Example 4

[0095] Dissolve 5g magnesium nitrate, 2g cerium nitrate, 2g copper nitrate, and 1g ferric nitrate in 100ml deionized water. Add 10g citric acid to the above solution and stir vigorously at 25℃ for 2 hours. Place the mixture in a water bath and raise the temperature to 80℃ for evaporation for 10 hours. Place the evaporated sample in an oven and dry at 150℃ for 24 hours. After drying, place the sample in a muffle furnace with an air atmosphere and calcine at 800℃ for 2 hours. Press the calcined catalyst into tablets, crush them into 20-40 mesh particles, and load them into a fixed-bed reactor for in-situ reduction of the catalyst using hydrogen at 750℃. After the reactor cools to 200℃, introduce the reactant methacrolein at a space velocity of 2h⁻¹. -1 The hydrogen flow rate was 40 ml / min, and the selectivity of methylpropenol is shown in Table 1.

[0096] Table 1 Activity evaluation results in the examples

[0097]

[0098] 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.

[0099] 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. A method for preparing 2-methylpropenol, characterized in that, The method includes: pre-reducing the catalyst, then contacting it with methacrolein and hydrogen to react and generate 2-methylpropenol; The catalyst is a binary metal oxide supported metal catalyst, which is prepared by the following method: 5g of lanthanum nitrate hexahydrate, 8g of nickel nitrate hexahydrate, 2g of cerium nitrate, and 1g of copper nitrate were dissolved in 40mL of deionized water. At the same time, 5g of citric acid, 2g of polyethylene glycol-400, and 3g of poloxamer F127 were added to the above solution. The solution was stirred vigorously and heated at 25°C for 2 hours. Then the solution was heated to 60°C and heated for 10 hours. The sample was dried at 100°C for 24 hours. The dried sample was then calcined at 800°C for 2 hours.

2. The preparation method according to claim 1, characterized in that, The mass hourly space velocity (MSV) of the methacrolein is 0.5–5 h⁻¹. -1 ; The reaction temperature is 50~250℃; The reaction pressure is 0.1~5.0 MPa; The molar ratio of hydrogen to methacrolein is 1:1 to 20:

1.

3. The preparation method according to claim 1, characterized in that, The pre-reduction atmosphere is a hydrogen atmosphere; The pre-reduction temperature is 300~800℃, and the pre-reduction time is 2h~3h.

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