Method for preparing alcohol compounds by using CeOx / Ni reverse phase interface catalyst for carbonyl hydrogenation

Abstract

The application discloses a CeOx / Ni reverse phase interface catalyst and application of the catalyst in preparation of alcohol compounds through carbonyl hydrogenation, and belongs to the technical field of catalysts. The catalyst takes Ni as a substrate, and CeOx as an active additive loaded on the surface of the Ni substrate to form a reverse phase interface structure. The loading amount of the CeOx is 1% to 10% of the total mass of the catalyst, and the CeOx is dispersed in the form of nano clusters with a size of 1 to 5 nm on the surface of the Ni. Through the design of the reverse phase interface structure, the electronic strong interaction between the Ni and the CeOx is strengthened, the Ni particle agglomeration is inhibited, the active sites are increased, and the catalytic activity and selectivity are improved. The catalyst has the advantages of simple preparation process, low cost and excellent stability. When the catalyst is used in the carbonyl hydrogenation reaction, the conversion rate of carbonyl compounds can be more than 95%, and the selectivity of alcohol products can be more than 98%. The catalyst can be widely applied to the preparation of alcohol compounds through the hydrogenation of various aldehyde, ketone and ester carbonyl compounds, and has important industrial application value.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to a CeOx / Ni reversed-phase interface catalyst and its application in the preparation of alcohols from the hydrogenation reaction of carbonyl compounds. Background Technology

[0002] Alcohols are important raw materials for fine chemicals, and catalytic hydrogenation of carbonyl compounds is one of the greenest and most efficient methods for preparing corresponding alcohols. Currently, the catalysts used in this reaction are mainly precious metals, which have problems such as high cost, resource scarcity, and susceptibility to poisoning and deactivation, thus limiting large-scale industrial application.

[0003] Non-precious metal Ni-based catalysts have become a research focus due to their low cost and high hydrogenation activity. However, pure Ni-based catalysts have defects such as easy agglomeration of nanoparticles and insufficient selectivity for carbonyl hydrogenation, which limit their catalytic performance and product yield.

[0004] CeOx is often used as a catalyst promoter due to its unique oxygen vacancy structure. However, most existing CeOx-Ni composite catalysts are Ni-supported CeOx in a normal phase structure, with weak interfacial interaction and poor synergistic effect, which cannot effectively solve the inherent defects of Ni-based catalysts.

[0005] Reverse interface structures (oxides supported on metal surfaces) can enhance metal-oxide interface interactions and improve catalytic performance. However, mature technologies for CeOx / Ni reverse interface catalysts to prepare alcohols by carbonyl hydrogenation have not yet been disclosed. Therefore, developing such high-performance, low-cost catalysts has significant theoretical and industrial value. Summary of the Invention

[0006] Purpose of the invention:

[0007] To address the problems of high cost of precious metal catalysts, insufficient activity and selectivity of Ni-based catalysts, and weak interfacial interactions in existing technologies, this invention provides a CeOx / Ni reversed-phase interfacial catalyst. This catalyst uses non-precious metal Ni as a substrate, with CeOx as a modifying component supported on the Ni surface to form a reversed-phase interfacial structure. Through interfacial synergy, it solves the defects of Ni particle agglomeration, insufficient active sites, and poor selectivity. Simultaneously, this catalyst provides applications in the preparation of alcohols by carbonyl hydrogenation, enabling efficient and highly selective hydrogenation of carbonyl compounds to corresponding alcohols, reducing production costs, and meeting the needs of industrial applications.

[0008] Technical solution:

[0009] I. A CeOx / Ni reverse interfacial catalyst and its preparation method:

[0010] The catalyst uses Ni as a substrate, with CeOx supported on the Ni substrate surface as an active promoter to form a reverse interface structure; the CeOx loading is 1%-10% of the total catalyst mass; the Ni substrate is Ni nanoparticles; and the CeOx is dispersed on the surface of the Ni nanoparticles in the form of nanoclusters. The preparation method of the CeOx / Ni reverse interface catalyst adopts a co-precipitation method, specifically including the following steps:

[0011] 1) Preparation of mixed salt solution: Add nickel salt, cerium salt and dispersant together to deionized water, stir for 30-60 min until completely dissolved to obtain mixed salt solution; wherein, the mass ratio of nickel salt to cerium salt is 10-100:1, and the amount of dispersant is 5%-20% of the total mass of nickel salt and cerium salt;

[0012] 2) Coprecipitation reaction: Place the mixed salt solution in a constant temperature water bath, control the temperature at 25-60℃, add the precipitant dropwise while stirring, adjust the pH of the solution to 8-10, and continue stirring for 1-4 hours after the addition is complete to form Ce-Ni composite precipitate;

[0013] 3) Aging and calcination: The composite precipitate was aged at 25-60℃ for 2-8 h, centrifuged, washed until neutral, dried and placed in a calcination furnace, calcined at 300-600℃ for 2-6 h in an inert gas atmosphere, and cooled to room temperature to obtain CeOx / Ni reverse interface catalyst.

[0014] Furthermore, when preparing the mixed salt solution, the nickel salt is one or more of nickel nitrate, nickel chloride, and nickel acetate; the cerium salt is one or more of cerium nitrate, cerium chloride, and cerium acetate; the dispersant is one or more of polyvinylpyrrolidone, sodium citrate, and sodium dodecylbenzenesulfonate; and in the mixed salt solution, the nickel ion concentration is 0.1-0.5 mol / L, and the cerium ion concentration is 0.001-0.05 mol / L.

[0015] Furthermore, during the coprecipitation reaction, the precipitant is one or more of ammonia, sodium hydroxide solution, sodium carbonate solution, and sodium bicarbonate solution; the dropping rate of the precipitant is 1-5 mL / min; and the stirring rate is 300-600 r / min.

[0016] Furthermore, during the aging process, the inert gas is one or both of nitrogen and argon; the drying temperature is 60-100℃, the drying time is 6-12 h, and the calcination heating rate is 2-5℃ / min.

[0017] II. CeOx / Ni reversed-phase interfacial catalyst for the preparation of alcohols by carbonyl hydrogenation: The carbonyl compound, solvent, and CeOx / Ni reversed-phase interfacial catalyst are added to a high-pressure reactor. Hydrogen gas is introduced to replace the air in the reactor 3-5 times. Then, the hydrogen pressure is adjusted to 0.5-5 MPa, the reaction temperature is controlled at 60-180℃, the stirring rate is 300-800 r / min, and the reaction is carried out for 1-10 hours. After the reaction is completed, the mixture is cooled, filtered, and separated to obtain the alcohol compound.

[0018] Further, the carbonyl compound is one or more of aldehydes, ketones, and esters; the aldehyde compound is selected from one or more of formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, furfural, and cinnamaldehyde; the ketone compound is selected from one or more of acetone, butanone, acetophenone, and cyclohexanone; and the ester compound is selected from one or more of ethyl acetate, methyl propionate, and ethyl benzoate.

[0019] Further, the solvent is one or more of methanol, ethanol, isopropanol, tetrahydrofuran, and cyclohexane; the amount of catalyst used is 0.5%-10% of the mass of the carbonyl compound; and the mass ratio of the carbonyl compound to the solvent is 2:20-100. Beneficial effects

[0020] (1) This invention employs a reversed-phase interface structure design, loading CeOx nanoclusters onto the surface of a Ni substrate, rather than the traditional method of loading Ni onto a CeOx support. This reversed-phase structure can construct abundant Ni-CeOx interfaces, strengthening the strong electronic interactions between the two and inducing the generation of electron-rich Ni-VO-Ce catalytic sites at the interface. This significantly improves the catalytic activity and selectivity of the catalyst, solving the problems of low activity and poor selectivity of traditional Ni-based catalysts.

[0021] (2) The catalyst of the present invention uses non-precious metal Ni as the main active component and CeOx as an auxiliary agent. The raw materials are inexpensive and abundant, avoiding the use of precious metals and greatly reducing the preparation cost of the catalyst, making it suitable for large-scale industrial application. At the same time, the catalyst preparation process is simple, convenient to operate, has good repeatability, and is easy to realize industrial production.

[0022] (3) Compared with existing catalysts that use precious metals such as rhenium as active components, the catalyst of the present invention does not require the use of expensive precious metals and the preparation process is simpler. At the same time, it has better catalytic performance and has a significant competitive advantage in the field of carbonyl hydrogenation to prepare alcohols. Compared with the traditional normal-phase CeOx / Ni catalyst, the catalyst of the present invention with reverse-phase interface structure has stronger interfacial interaction, more significant synergistic effect, and significantly improved catalytic performance. Detailed Implementation

[0023] Example 1: Preparation of 4% CeOx / Ni reverse interfacial catalyst

[0024] Weigh 2.91 g of nickel nitrate (Ni(NO3)2·6H2O), 0.08 g of cerium nitrate (Ce(NO3)3·6H2O), and 0.3 g of polyvinylpyrrolidone (PVP), and add them together to 50 mL of deionized water. Stir for 40 min until completely dissolved to obtain a mixed salt solution (nickel ion concentration approximately 0.2 mol / L, cerium ion concentration approximately 0.008 mol / L). Place the mixed salt solution in a constant temperature water bath at 40℃, stir at a rate of 300 r / min, and add ammonia water (precipitant) dropwise at a rate of 2 mL / min. Adjust the pH of the solution to 9. After the addition is complete, continue stirring for 1.5 h to form a pale yellow Ce-Ni composite precipitate. Age the above composite precipitate at 40℃ for 4 h, centrifuge (8000 r / min, 10 min), wash with deionized water until neutral, dry at 80℃ for 8 h, and then place it in a calcining furnace and purge with argon gas (flow rate 50). The temperature was increased to 450℃ at a rate of 3℃ / min, calcined for 3 h, and then cooled to room temperature to obtain a CeOx / Ni reverse interface catalyst (CeOx loading was 4%, and CeOx nanoclusters had a particle size of about 4 nm).

[0025] Example 2: Preparation of 2.5% CeOx / Ni reverse interfacial catalyst

[0026] Weigh out 3.5 g of nickel chloride (NiCl2·6H2O), 0.05 g of cerium chloride (CeCl3·7H2O), and 0.4 g of sodium citrate, and add them together to 60 mL of deionized water. Stir for 45 min until completely dissolved to obtain a mixed salt solution (nickel ion concentration approximately 0.22 mol / L, cerium ion concentration approximately 0.004 mol / L). Place the mixed salt solution in a constant temperature water bath at 50℃ and stir at a rate of 400 r / min. Add sodium hydroxide solution (concentration 1 mol / L, precipitant) dropwise at a rate of 3 mL / min. Adjust the pH of the solution to 8.5. After the addition is complete, continue stirring for 2 h to form a light green Ce-Ni composite precipitate. The composite precipitate was aged at 50°C for 3 h, centrifuged (8000 r / min, 10 min), washed with deionized water until neutral, dried at 90°C for 6 h, and then placed in a calcination furnace. Nitrogen gas was introduced (flow rate of 60 mL / min), and the temperature was increased to 500°C at a rate of 4°C / min. The calcination was carried out for 2.5 h and then cooled to room temperature to obtain a CeOx / Ni reverse interfacial catalyst (CeOx loading of 2.5%, CeOx nanocluster particle size of about 3 nm).

[0027] Example 3: Application of CeOx / Ni reversed-phase interfacial catalyst in the hydrogenation of benzaldehyde to benzyl alcohol

[0028] 5.3 g benzaldehyde, 20 mL ethanol, and 0.15 g of the CeOx / Ni reversed-phase interfacial catalyst prepared in Example 1 were added to a 50 mL high-pressure reactor. Hydrogen gas was introduced to replace the air in the reactor four times. The hydrogen pressure was adjusted to 2 MPa, the temperature was raised to 120 °C, the stirring rate was 500 r / min, and the reaction was carried out for 4 h. After the reaction was completed, the mixture was cooled to room temperature, the catalyst was separated by filtration, and the filtrate was analyzed by gas chromatography.

[0029] Experimental results: The conversion rate of benzaldehyde was 98.2%, the selectivity of benzyl alcohol was 99.1%, and the yield of benzyl alcohol was 97.3%.

[0030] Example 4: Application of CeOx / Ni reversed-phase interfacial catalyst in the hydrogenation of cyclohexanone to cyclohexanol.

[0031] 5.0 g of cyclohexanone, 25 mL of isopropanol, and 0.2 g of the CeOx / Ni reversed-phase interfacial catalyst prepared in Example 2 were added to a 50 mL high-pressure reactor. Hydrogen gas was introduced to replace the air in the reactor three times. The hydrogen pressure was adjusted to 1.5 MPa, the temperature was raised to 100 °C, the stirring rate was 600 r / min, and the reaction was carried out for 3 h. After the reaction was completed, the mixture was cooled to room temperature, the catalyst was separated by filtration, and the filtrate was analyzed by gas chromatography.

[0032] Experimental results: Cyclohexanone conversion rate was 96.8%, cyclohexanol selectivity was 98.7%, and cyclohexanol yield was 95.5%.

[0033] Example 5: Application of CeOx / Ni reversed-phase interfacial catalyst in the hydrogenation of methyl 1,4-cyclohexanedicarboxylate to 1,4-cyclohexanediethanol

[0034] 8.6 g of methyl 1,4-cyclohexanedicarboxylate, 40 mL of isopropanol, and 0.3 g of the CeOx / Ni reversed-phase interfacial catalyst prepared in Example 1 were added to a 100 mL high-pressure reactor. Hydrogen gas was introduced to replace the air in the reactor five times. The hydrogen pressure was adjusted to 3 MPa, the temperature was raised to 150 °C, the stirring rate was 700 r / min, and the reaction was carried out for 6 h. After the reaction was completed, the reactor was cooled to room temperature, the catalyst was separated by filtration, and the filtrate was analyzed by gas chromatography.

[0035] Experimental results: The conversion rate of methyl 1,4-cyclohexanedicarboxylate was 99.0%, the selectivity of 1,4-cyclohexanediethanol was 98.8%, and the yield of 1,4-cyclohexanediethanol was 97.8%.

[0036] Comparative Example 1: Preparation and Application of Traditional Normal-Phase Ni / CeOx Catalysts

[0037] Weigh 1.0 g of CeO2 support (particle size approximately 50 nm), disperse it in 40 mL of deionized water, and sonicate for 20 min. Weigh 2.91 g of nickel nitrate, dissolve it in 10 mL of deionized water, add it dropwise to the CeO2 dispersion, stir for 45 min, adjust the pH to 9 with ammonia, age at 40 °C for 4 h, centrifuge, wash, dry, and calcine at 450 °C under an argon atmosphere for 3 h to obtain the Ni / CeOx normal phase catalyst (Ni loading 20%).

[0038] Using the reaction conditions of Example 3, the normal-phase catalyst was used instead of the reverse-phase catalyst of Example 1 for the hydrogenation reaction of benzaldehyde. The analysis results showed that the benzaldehyde conversion rate was 78.5% and the selectivity of benzyl alcohol was 89.2%, which was far lower than the performance of the reverse-phase interfacial catalyst of the present invention.

[0039] Comparative Example 2: Application of Pure Ni Catalyst Using the pure Ni nanoparticles prepared in step 1 of Example 1 as a catalyst, benzaldehyde hydrogenation reaction was carried out according to the reaction conditions of Example 3. The analysis results showed that the benzaldehyde conversion rate was 65.3% and the benzyl alcohol selectivity was 76.8%, which was lower than that of the present invention.

[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A CeOx / Ni reverse interfacial catalyst, characterized in that: Using Ni as a substrate, CeOx is loaded onto the surface of the Ni substrate as an active agent to form a reverse interface structure; the loading amount of CeOx is 1%-10% of the total mass of the catalyst; the Ni substrate is Ni nanoparticles; the CeOx is dispersed on the surface of the Ni nanoparticles in the form of nanoclusters.

2. The CeOx / Ni reverse interfacial catalyst according to claim 1, characterized in that: The CeOx loading is 2%-6% of the total catalyst mass; the Ni nanoparticles have a particle size of 15-30 nm; and the CeOx nanoclusters have a particle size of 1-5 nm.

3. The method for preparing the CeOx / Ni reverse interfacial catalyst according to claim 1, characterized in that, Includes the following steps: 1) Preparation of mixed salt solution: Add nickel salt, cerium salt and dispersant together to deionized water, stir for 30-60 min until completely dissolved to obtain mixed salt solution; wherein, the mass ratio of nickel salt to cerium salt is 10-100:1, and the amount of dispersant is 5%-20% of the total mass of nickel salt and cerium salt; 2) Coprecipitation reaction: Place the mixed salt solution in a constant temperature water bath, control the temperature at 25-60℃, add the precipitant dropwise while stirring, adjust the pH value of the solution to 8-10, and continue stirring for 1-4 h after the addition is complete to form Ce-Ni composite precipitate; 3) Aging and calcination: Aging the composite precipitate at 25-60℃ for 2-8 h, centrifuge, wash until neutral, dry and place in a calcination furnace, calcining at 300-600℃ for 2-6 h in an inert gas atmosphere, and cooling to room temperature to obtain CeOx / Ni reverse interface catalyst.

4. The preparation method according to claim 3, characterized in that: When preparing the mixed salt solution, the nickel salt is one or more of nickel nitrate, nickel chloride, and nickel acetate; the cerium salt is one or more of cerium nitrate, cerium chloride, and cerium acetate; the dispersant is one or more of polyvinylpyrrolidone, sodium citrate, and sodium dodecylbenzenesulfonate; and the nickel ion concentration in the mixed salt solution is 0.1-0.5 mol / L, and the cerium ion concentration is 0.001-0.05 mol / L.

5. The preparation method according to claim 3, characterized in that: During the coprecipitation reaction, the precipitant is one or more of ammonia, sodium hydroxide solution, sodium carbonate solution, and sodium bicarbonate solution; the dropping rate of the precipitant is 1-5 mL / min; and the stirring rate is 300-600 r / min.

6. The preparation method according to claim 3, characterized in that: During the aging process, the inert gas is one or both of nitrogen and argon; the drying temperature is 60-100℃, the drying time is 6-12 h; and the calcination heating rate is 2-5℃ / min.

7. The application of the CeOx / Ni reverse interfacial catalyst according to any one of claims 1-3 in the carbonyl hydrogenation preparation of alcohols, characterized in that: Carbonyl compounds, solvents, and CeOx / Ni reverse interfacial catalysts are added to a high-pressure reactor. Hydrogen gas is introduced to replace the air in the reactor 3-5 times. The hydrogen pressure is adjusted to 0.5-8 MPa, the reaction temperature is controlled at 60-250℃, the stirring rate is 300-800 r / min, and the reaction is carried out for 1-15 h. After the reaction is completed, the mixture is cooled, filtered, and separated to obtain alcohol compounds.

8. The application according to claim 7, characterized in that: The carbonyl compound is one or more of aldehydes, ketones, and esters; the aldehyde compound is selected from one or more of formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, furfural, and cinnamaldehyde; the ketone compound is selected from one or more of acetone, butanone, acetophenone, and cyclohexanone; and the ester compound is selected from one or more of ethyl acetate, methyl propionate, and ethyl benzoate.

9. The application according to claim 7, characterized in that: The solvent is one or more of methanol, ethanol, isopropanol, tetrahydrofuran, and cyclohexane; the amount of catalyst used is 0.5%-10% of the mass of the carbonyl compound; the mass ratio of the carbonyl compound to the solvent is 2:20-100.