CN113441143B - Nickel-cobalt-aluminum ternary metal composite catalyst and preparation method and application thereof - Google Patents

Abstract

The invention discloses a nickel-cobalt-aluminum ternary metal composite catalyst and its preparation method and application. The Ni-Co-Al composite ternary metal catalyst is formed by urea hydrolysis co-precipitation method and then calcined and reduced. The catalyst is marked as xNiyCoAl, wherein x represents the molar ratio of nickel element to Al element, x=1.5-2.5, y represents the molar ratio of Co element to Al element, y=0.25-2. The catalyst can efficiently catalyze the hydrogenation of levulinic acid to synthesize γ-valerolactone in 1,4-dioxane under mild reaction conditions. The catalyst has high catalytic activity, and the yield of γ-valerolactone can reach 100% under the catalytic reaction conditions of 120-130°C and 3-4MPa H ₂ for 2-3h; while other reported non-precious metal catalysts usually A similar catalytic effect can be achieved at a reaction temperature of 140-200°C.

Description

A kind of nickel-cobalt-aluminum ternary metal composite catalyst and its preparation method and application

technical field

The invention belongs to the field of catalysts, and in particular relates to a nickel-cobalt-aluminum ternary metal composite catalyst and a preparation method and application thereof.

Background technique

Biomass is a natural clean renewable carbon resource with wide sources, abundant reserves and low price. Biomass can be converted into a variety of important high-value-added fuels, chemical products and materials, and has great potential to replace traditional fossil resources, and exploring methods for more efficient use of biomass resources is also attracting widespread attention. Among them, converting biomass raw materials into various biomass-based platform compounds, and then converting them into high-value-added chemicals is generally considered to be an important way to utilize biomass resources. Levulinic acid is an important biomass-based platform molecule, and its catalytic hydrogenation can produce γ-valerolactone, which has a wide range of applications in green solvents, organic synthesis, and fuel additives.

At present, most of the solvent systems for the direct hydrogenation of levulinic acid to prepare γ-valerolactone are organic solvents such as 1,4-dioxane. Because hydrogen has a high solubility in 1,4-dioxane, 1,4-dioxane is considered to be an ideal hydrogenation reaction solvent, and can achieve higher γ-valerolactone production. Rate (ACS Catalysis,2016,6(8):5462-5472; Chemical Engineering Journal,2019,369:386-393; Catalysis Letters,2017,147(3):1-7; Catalysts,2015,6(1) :6-15.). However, the current reaction conditions of the 1,4-dioxane system are relatively harsh, especially when using non-noble metal catalysts, the reaction temperature is mostly between 140-200°C (Fuel, 2020, 259:116208.1-116208.4; Catalysis Letters ,2017,147(3):1-7; Catalysts,2015,6(1):6-15; Catalysis Today,2016,274:55-59; Catalysis Today,2017,309:189-194), and more The efficiency of preparing γ-valerolactone from levulinic acid under mild conditions is relatively low. And currently other reported non-precious metal catalysts usually require a reaction temperature of 140-200°C to achieve similar catalytic effects.

Non-precious metals have more application prospects than precious metals due to their abundant reserves and relatively low cost. The development of non-precious metal catalysts with high catalytic activity and the efficient hydrogenation and reduction of levulinic acid under mild conditions in the 1,4-dioxane system have become a major technical difficulty in the industrial production of γ-valerolactone.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, and provide a nickel-cobalt-aluminum ternary metal composite catalyst and its preparation method and application. The invention provides a nickel-cobalt-aluminum ternary metal composite hydrogenation catalyst, which can efficiently catalyze the hydrogenation of levulinic acid to synthesize γ-valerolactone in a 1,4-dioxane system under mild conditions.

One of the technical solutions of the present invention is to provide a nickel-cobalt-aluminum ternary metal composite catalyst prepared according to the above preparation method. The catalyst is marked as xNiyCoAl, where x represents the molar ratio of Ni and Al elements in the catalyst, x=1.5-2.5, and y represents the molar ratio of Co and Al elements in the catalyst, y=0.25-2.

The second technical solution of the present invention is to provide a method for preparing a nickel-cobalt-aluminum ternary metal composite catalyst, which specifically includes the following steps: dissolving cobalt nitrate hexahydrate, urea, nickel nitrate hexahydrate and aluminum nitrate nonahydrate in In ionized water; react at 100-140°C for 3-5h, separate solid from liquid, grind the solid into powder after precipitation and drying; calcinate at 400-600°C for 3-5h, then reduce at 550-750°C for 4-6h under protective gas, A nickel-cobalt-aluminum ternary metal composite catalyst is obtained.

In a preferred embodiment of the present invention, the catalyst is marked as xNiyCoAl, where x represents the molar ratio of Ni to Al, and y represents the molar ratio of Co to Al in the catalyst.

In a preferred embodiment of the present invention, the molar ratio of the nickel element to the aluminum element is 1.5-2.5:1.

In a preferred embodiment of the present invention, the molar ratio of the cobalt element to the aluminum element is 0.25-2:1.

In a preferred embodiment of the present invention, the total molar ratio of urea to nickel, cobalt and aluminum is 13-14:1.

In a preferred embodiment of the present invention, in the aqueous solution containing nickel nitrate, cobalt nitrate, aluminum nitrate and urea, the concentration of urea is 3-5 mol/L, and the concentration of cobalt nitrate is 0.015-0.15 mol/L.

In a preferred embodiment of the present invention, the calcination is carried out under air atmosphere.

In a preferred embodiment of the present invention, the protective gas is 10% vol% hydrogen + 90% vol% nitrogen.

The third technical solution of the present invention is to provide an application of a nickel-cobalt-aluminum ternary metal composite catalyst in the preparation of γ-valerolactone.

The fourth technical solution of the present invention is to provide a method for preparing γ-valerolactone with a nickel-cobalt-aluminum ternary metal composite catalyst, which specifically includes the following steps: mixing levulinic acid and solvent 1,4-dioxane Then put it in a reaction vessel, add a nickel-cobalt-aluminum ternary metal composite catalyst, seal the reactor and fill it with hydrogen, the hydrogen pressure is 1-4MPa, the reactor temperature is 100-130°C, and the reaction time is 1-3h. More preferably, the hydrogen pressure is 2-4MPa, the reaction temperature is 120-130°C, and the reaction time is 2-3h. Under the above conditions, the yield of γ-valerolactone is about 90.7-100%.

The equipment, reagents, processes, parameters, etc. involved in the present invention are all conventional equipment, reagents, processes, parameters, etc., unless otherwise specified, and are no longer examples.

All ranges recited herein include all points within that range.

"About", "approximately" or "about" in the present invention means within ±20% of the stated range or numerical value.

In the present invention, the "room temperature" is the normal ambient temperature, which may be 10-30°C.

Compared with the background technology, this technical solution has the following advantages:

(1) The present invention forms Ni-Co-Al composite ternary metal catalyst by urea hydrolysis co-precipitation method and then calcined reduction;

(2) The catalyst prepared by the present invention has high-efficiency catalytic activity, and efficiently catalyzes the hydrogenation of levulinic acid to synthesize γ-valerolactone under mild reaction conditions in 1,4-dioxane;

(3) Catalyst prepared by the present invention reacts 2-3h under the catalytic reaction condition of 120-130 ℃ and _3-4MPa H , gamma-valerolactone productive rate can reach 100%; Catalytic reaction temperature is lower than in the prior art The reaction temperature of the non-noble metal catalyst is 140-200°C, and a similar catalytic effect can be achieved.

detailed description

The invention provides a method for preparing a nickel-cobalt-aluminum ternary metal composite catalyst, which specifically comprises the following steps: dissolving cobalt nitrate hexahydrate, urea, nickel nitrate hexahydrate and aluminum nitrate nonahydrate in deionized water, and the concentration of urea 3-5mol/L, the concentration of cobalt nitrate is 0.015-0.15mol/L, the molar ratio of nickel and aluminum is 1.5-2.5:1, the molar ratio of cobalt and aluminum is 0.25-2:1, urea The total molar ratio with nickel, cobalt, and aluminum is 13-14:1; react at 100-140°C for 3-5h, separate solid from liquid, and grind the solid precipitate into powder after drying; Calcining at 600° C. for 3-5 hours, and then reducing at 550-750° C. for 4-6 hours in a protective atmosphere of 10% vol% hydrogen + 90% vol% nitrogen to obtain a nickel-cobalt-aluminum ternary metal composite catalyst. The catalyst is marked as xNiyCoAl, where x represents the molar ratio of Ni and Al elements, x=1.5-2.5, and y represents the molar ratio of Co and Al elements in the catalyst, y=0.25-2.

The invention provides a method for preparing γ-valerolactone with a nickel-cobalt-aluminum ternary metal composite catalyst, which specifically includes the following steps: mixing levulinic acid and a solvent 1,4-dioxane and placing them in a reaction vessel , adding a nickel-cobalt-aluminum ternary metal composite catalyst, sealing the reactor and filling it with hydrogen, the hydrogen pressure is 1-4MPa, the reactor temperature is 100-130°C, and the reaction time is 1-3h. More preferably, the hydrogen pressure is 2-3MPa, the reaction temperature is 120-130°C, and the reaction time is 2-3h.

In order to make the purpose, technical solution and advantages of the present invention clearer, the content of the present invention will be described in more detail through examples below, but the protection scope of the present invention is not limited to these examples.

Example 1

Prepare a nickel-cobalt-aluminum ternary metal composite catalyst:

Dissolve 2.907g (0.01mol) nickel nitrate hexahydrate, 1.88g (0.005mol) aluminum nitrate nonahydrate, 0.364g cobalt nitrate hexahydrate (0.00125mol) and 13.5g urea in 70mL deionized water; After 4 hours of reaction at low temperature, the solid precipitate was separated; the dried solid was ground into powder, and then calcined at 500 ° C in air atmosphere for 4 hours, and then the calcined solid was in 10% vol% hydrogen + 90% vol% nitrogen atmosphere The nickel-cobalt-aluminum ternary metal composite catalyst can be obtained by calcining and reducing at 650°C for 5 hours. The above catalyst is labeled 2Ni0.25CoAl.

Prepare the following gamma-valerolactone with the nickel-cobalt-aluminum ternary metal composite catalyst prepared above:

Add 0.125g of levulinic acid and 5ml of 1,4-dioxane to a 25mL autoclave, then add 0.075g of 2Ni0.25CoAl as a catalyst, seal the reaction vessel, feed 3MPa hydrogen, magnetically stir, heat to 100°C and keep After 2 hours, finish the reaction and cool to room temperature and take a sample for detection. The detection results are listed in Table 1 as 1.

Example 2

Prepare a nickel-cobalt-aluminum ternary metal composite catalyst:

Dissolve 2.907g (0.01mol) nickel nitrate hexahydrate, 1.88g (0.005mol) aluminum nitrate nonahydrate, 0.7275g cobalt nitrate hexahydrate (0.0025mol) and 14.4g urea in 70mL deionized water; After 4 hours of reaction at low temperature, the solid precipitate was separated; the dried solid was ground into powder, and then calcined at 500 ° C in air atmosphere for 4 hours, and then the calcined solid was in 10% vol% hydrogen + 90% vol% nitrogen atmosphere The nickel-cobalt-aluminum ternary metal composite catalyst can be obtained by calcining and reducing at 650°C for 5 hours. The above catalyst is labeled 2Ni0.5CoAl.

Prepare the following gamma-valerolactone with the nickel-cobalt-aluminum ternary metal composite catalyst prepared above:

Add 0.125g of levulinic acid and 5ml of 1,4-dioxane to a 25mL autoclave, then add 0.075g of 2Ni0.5CoAl as a catalyst, seal the reaction vessel, feed 3MPa hydrogen, magnetically stir, heat to 100°C and keep After 2 hours, finish the reaction and cool to room temperature and take a sample for detection. The detection results are listed in Table 1 as 2.

Example 3

Prepare a nickel-cobalt-aluminum ternary metal composite catalyst:

Dissolve 2.907g (0.01mol) nickel nitrate hexahydrate, 1.88g (0.005mol) aluminum nitrate nonahydrate, 1.455g cobalt nitrate hexahydrate (0.005mol) and 16.2g urea in 70mL deionized water; After 4 hours of reaction at low temperature, the solid precipitate was separated; the dried solid was ground into powder, and then calcined at 500 ° C in air atmosphere for 4 hours, and then the calcined solid was in 10% vol% hydrogen + 90% vol% nitrogen atmosphere The nickel-cobalt-aluminum ternary metal composite catalyst can be obtained by calcining and reducing at 650°C for 5 hours. The above catalyst is labeled 2Ni1CoAl.

Prepare the following gamma-valerolactone with the nickel-cobalt-aluminum ternary metal composite catalyst prepared above:

Add 0.125g of levulinic acid and 5ml of 1,4-dioxane into a 25mL autoclave, then add 0.075g of 2Ni1CoAl as a catalyst, seal the autoclave, feed 3MPa hydrogen, magnetically stir, heat to 100°C and keep it for 2 hours , finish the reaction and cool to room temperature and take a sample for detection. The detection results are listed in Table 1 as 3.

Example 4

Prepare a nickel-cobalt-aluminum ternary metal composite catalyst:

Dissolve 2.907g (0.01mol) nickel nitrate hexahydrate, 1.88g (0.005mol) aluminum nitrate nonahydrate, 2.91g cobalt nitrate hexahydrate (0.01mol) and 19.8g urea in 70mL deionized water; After 4 hours of reaction at low temperature, the solid precipitate was separated; the dried solid was ground into powder, and then calcined at 500 ° C in air atmosphere for 4 hours, and then the calcined solid was in 10% vol% hydrogen + 90% vol% nitrogen atmosphere The nickel-cobalt-aluminum ternary metal composite catalyst can be obtained by calcining and reducing at 650°C for 5 hours. The above catalyst is labeled 2Ni2CoAl.

Prepare the following gamma-valerolactone with the nickel-cobalt-aluminum ternary metal composite catalyst prepared above:

Add 0.125g of levulinic acid and 5ml of 1,4-dioxane into a 25mL autoclave, then add 0.075g of 2Ni2CoAl as a catalyst, seal the autoclave, feed 3MPa hydrogen, magnetically stir, heat to 100°C and keep for 2 hours , Finish the reaction and cool to room temperature and take a sample for testing. The test results are listed in Table 1 with the serial number 4.

Example 5-8

Prepare a nickel-cobalt-aluminum ternary metal composite catalyst:

Dissolve 2.907g (0.01mol) nickel nitrate hexahydrate, 1.88g (0.005mol) aluminum nitrate nonahydrate, 0.7275g cobalt nitrate hexahydrate (0.0025mol) and 14.4g urea in 70mL deionized water; After 4 hours of reaction at low temperature, the solid precipitate was separated; the dried solid was ground into powder, and then calcined at 500 ° C in air atmosphere for 4 hours, and then the calcined solid was in 10% vol% hydrogen + 90% vol% nitrogen atmosphere The nickel-cobalt-aluminum ternary metal composite catalyst can be obtained by calcining and reducing at 650°C for 5 hours. The above catalyst is labeled 2Ni0.5CoAl.

Prepare the following gamma-valerolactone with the nickel-cobalt-aluminum ternary metal composite catalyst prepared above:

Add 0.125g of levulinic acid and 5ml of 1,4-dioxane into a 25mL autoclave, then add 0.075g of 2Ni0.5CoAl as a catalyst, seal the reaction vessel, feed in 3MPa hydrogen, magnetically stir, and heat to 100°C, 110 °C, 120 °C and 130 °C and keep it for 2 hours, after finishing the reaction, cool to room temperature and take samples for testing. The testing results are listed in Table 1, numbered 5-8.

Examples 9-12

Prepare a nickel-cobalt-aluminum ternary metal composite catalyst:

Dissolve 2.907g (0.01mol) nickel nitrate hexahydrate, 1.88g (0.005mol) aluminum nitrate nonahydrate, 0.7275g cobalt nitrate hexahydrate (0.0025mol) and 14.4g urea in 70mL deionized water; After 4 hours of reaction at low temperature, the solid precipitate was separated; the dried solid was ground into powder, and then calcined at 500 ° C in air atmosphere for 4 hours, and then the calcined solid was in 10% vol% hydrogen + 90% vol% nitrogen atmosphere The nickel-cobalt-aluminum ternary metal composite catalyst can be obtained by calcining and reducing at 650°C for 5 hours. The above catalyst is labeled 2Ni0.5CoAl.

Prepare the following gamma-valerolactone with the nickel-cobalt-aluminum ternary metal composite catalyst prepared above:

Add 0.125g of levulinic acid and 5ml of 1,4-dioxane to a 25mL autoclave, then add 0.075g of 2Ni0.5CoAl as a catalyst, seal the reaction vessel, feed 1MPa, 2MPa, 3MPa and 4MPa hydrogen, and magnetically stir, Heating to 120° C. and maintaining for 2 hours, finishing the reaction, cooling to room temperature and taking samples for testing. The testing results are listed in Table 1 as serial numbers 9-12.

Examples 13-15

Prepare a nickel-cobalt-aluminum ternary metal composite catalyst:

Dissolve 2.907g (0.01mol) nickel nitrate hexahydrate, 1.88g (0.005mol) aluminum nitrate nonahydrate, 0.7275g cobalt nitrate hexahydrate (0.0025mol) and 14.4g urea in 70mL deionized water; After 4 hours of reaction at low temperature, the solid precipitate was separated; the dried solid was ground into powder, and then calcined at 500 ° C in air atmosphere for 4 hours, and then the calcined solid was in 10% vol% hydrogen + 90% vol% nitrogen atmosphere The nickel-cobalt-aluminum ternary metal composite catalyst can be obtained by calcining and reducing at 650°C for 5 hours. The above catalyst is labeled 2Ni0.5CoAl.

Prepare the following gamma-valerolactone with the nickel-cobalt-aluminum ternary metal composite catalyst prepared above:

Add 0.125g of levulinic acid and 5ml of 1,4-dioxane to a 25mL autoclave, then add 0.075g of 2Ni0.5CoAl as a catalyst, seal the reaction vessel, feed 3MPa hydrogen, magnetically stir, heat to 120°C and keep After 1 hour, 2 hours and 3 hours, the reaction was completed and cooled to room temperature and samples were taken for detection. The detection results are listed in Table 1 as serial numbers 13-15.

The detection result in each embodiment of table 1

The above is only a preferred embodiment of the present invention, so the scope of the present invention cannot be limited accordingly, that is, the equivalent changes and modifications made according to the patent scope of the present invention and the content of the specification should still be covered by the present invention within range.

Claims (5)

1. The nickel-cobalt-aluminum ternary metal composite catalyst is characterized in that the catalyst is marked as xNiyCoAl, wherein x represents the molar ratio of Ni element to Al element, x =2,y represents the molar ratio of Co element to Al element, and y =0.5;

the catalyst is prepared by the following method: dissolving cobalt nitrate hexahydrate, urea, nickel nitrate hexahydrate and aluminum nitrate nonahydrate in deionized water; reacting at 110-140 deg.C for 3-5h, separating solid and liquid, drying the solid precipitate, and grinding into powder; calcining at 400-600 ℃ for 3-4h, and then reducing at 550-750 ℃ for 4-6h under protective gas to obtain the nickel-cobalt-aluminum ternary metal composite catalyst;

the catalyst is applied to the preparation of gamma-valerolactone, and the preparation method comprises the following steps: mixing levulinic acid and a solvent 1,4-dioxane, placing the mixture into a reaction container, adding a nickel-cobalt-aluminum ternary metal composite catalyst, sealing the reactor, and filling hydrogen, wherein the hydrogen pressure is 3-4MPa, the temperature of the reactor is 120-130 ℃, and the reaction time is 2-3h.

2. The Ni-Co-Al ternary metal composite catalyst according to claim 1, wherein the molar ratio of urea to the total of the three elements of Ni, co and Al is 12.5-14.5.

3. The nickel-cobalt-aluminum ternary metal composite catalyst according to claim 1, wherein in the aqueous solution containing nickel nitrate, cobalt nitrate, aluminum nitrate and urea, the concentration of urea is 3 to 5mol/L, and the concentration of cobalt nitrate is 0.015 to 0.15mol/L.

4. The Ni-Co-Al ternary metal composite catalyst according to claim 1, wherein the calcination is performed in an air atmosphere.

5. The Ni-Co-Al ternary metal composite catalyst according to claim 1, wherein the protective gas is 10% vol% H +90% vol% N.