A hydrogenation catalyst, its preparation and use

Abstract

The present application relates to a kind of hydrogenation catalyst and its preparation method and use, the hydrogenation catalyst includes carrier and active component supported on the carrier;The active component includes ruthenium cobalt alloy;The carrier includes active mesoporous carbon, the active mesoporous carbon is prepared by the following method, the method includes: mixing carbon precursor, iron oxide precursor and binder, then successively forming and crushing, after roasting in protective atmosphere, obtain the carrier precursor containing iron oxide;The carrier precursor and iron chloride are roasted in activation atmosphere, obtain the active mesoporous carbon.The hydrogenation catalyst provided by the present application has good service life, is suitable for the reaction of unsaturated alkenyl aldehyde hydrogenation preparation unsaturated alkenyl alcohol, has higher target product yield and selectivity.

Description

Technical Field

[0001] This invention relates to the field of hydrogenation catalyst technology, specifically to a hydrogenation catalyst, its preparation method, and its uses. Background Technology

[0002] Citral (3,7-dimethyl-2,6-octadienal) has two cis-trans isomers and is an important open-chain monoterpene aldehyde. As a key raw material for fragrances and pharmaceutical intermediates, citral yields a variety of reaction products through selective hydrogenation, mainly including nerol, geraniol, citronellol, and citronellol, which have significant applications. For example, citronellol is an important fragrance raw material with a sweet floral aroma, similar to rose, and is commonly used in rose or citrus fragrances; citronellol can also be used in food flavorings, such as in soft drinks, baked goods, candies, or jellies and puddings, and is one of the major fragrance raw materials.

[0003] Currently, hydrogenation catalysts used in hydrogenation reactions include many catalysts capable of hydrogenating olefinic double bonds or carbonyl groups, such as Raney series catalysts and ruthenium-based supported catalysts. However, in actual selective hydrogenation processes, the formation of over-hydrogenation products and small amounts of dimers or trimers of unsaturated aldehydes as byproducts are often accompanied by the acquisition of the target product (nerol, geraniol, or citronellol), indicating poor selectivity. For example, CN1422693A discloses the preparation of a ruthenium / iron catalyst supported on carbon. In the process of catalyzing the formation of nerol or geraniol, the content of the over-hydrogenation product citronellol can reach up to 4.3 wt%, and the content of nerol isomers I-III produced by olefin isomerization can reach up to 2.5 wt%, making it difficult to avoid the formation of byproducts and resulting in low selectivity.

[0004] In addition, the activity of hydrogenation catalysts also faces challenges. Due to the instability of unsaturated alkenes, a certain amount of low-boiling-point and high-boiling-point compounds are generated during the reaction. Some of these compounds have an irreversible effect on the activity of the catalyst, making it impossible to recycle the catalyst and increasing production costs.

[0005] Therefore, providing a hydrogenation catalyst with good yield, selectivity and lifetime for the hydrogenation reaction to prepare unsaturated enols has important application prospects and economic value. Summary of the Invention

[0006] To address the above problems, the present invention aims to provide a hydrogenation catalyst, its preparation method, and its applications. Compared with the prior art, the hydrogenation catalyst provided by the present invention has a good service life, is suitable for the hydrogenation of unsaturated enaldehydes to prepare unsaturated enols, and has a high yield and selectivity of the target product.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a hydrogenation catalyst, the hydrogenation catalyst comprising a support and an active component supported on the support;

[0009] The active component includes a ruthenium-cobalt alloy;

[0010] The carrier comprises active mesoporous carbon, which is prepared by the following method: mixing a carbon precursor, an iron oxide precursor and a binder, then sequentially molding and crushing them, followed by calcination under a protective atmosphere to obtain an iron oxide-containing carrier precursor; calcining the carrier precursor and ferric chloride under an activating atmosphere to obtain the active mesoporous carbon.

[0011] The hydrogenation catalyst provided by this invention uses ruthenium-cobalt alloy as the active component and active mesoporous carbon as the support, exhibiting excellent catalytic activity and selectivity. When used in the hydrogenation of unsaturated enaldehydes to prepare unsaturated enols, it avoids the formation of byproducts, thereby extending the catalyst's lifetime. The active mesoporous carbon support provided by this invention generates ferrous chloride and oxygen through the reaction of iron oxide and ferric chloride at high temperature. The ferrous chloride then sublimates under high temperature conditions, resulting in a rich and complex pore structure. The ruthenium-cobalt alloy, supported within the pores of the active mesoporous carbon, exerts excellent catalytic effects. Simultaneously, the introduced activating atmosphere deposits active functional groups on the support surface, further enhancing the catalytic effect.

[0012] Preferably, the average pore size of the active mesoporous carbon is 20-150 nm, for example, it can be 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm or 150 nm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0013] Preferably, the porosity of the active mesoporous carbon is 0.4-2 mL / g, for example, it can be 0.4 mL / g, 0.6 mL / g, 0.8 mL / g, 1 mL / g, 1.2 mL / g, 1.4 mL / g, 1.6 mL / g, 1.8 mL / g or 2 mL / g, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0014] Preferably, the specific surface area of ​​the active mesoporous carbon is 300-1000 m². 2 / g, for example, could be 300m 2 / g、400m 2 / g、500m 2 / g、600m 2 / g、700m2 / g、800m 2 / g、900m 2 / g or 1000m 2 / g, but not limited to the listed values, other unlisted values ​​within the range also apply.

[0015] Preferably, the average particle size of the active mesoporous carbon is 10-100 μm, for example, it can be 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm or 100 μm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0016] Preferably, in the hydrogenation catalyst, the mass of ruthenium accounts for 0.1-10% of the mass of the support, for example, it can be 0.1%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 1-5%.

[0017] Preferably, in the hydrogenation catalyst, the mass of cobalt accounts for 0.01-5% of the mass of the support, for example, it can be 0.01%, 1%, 2%, 3%, 4% or 5%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 0.1-1%.

[0018] In this invention, it is preferable to control the percentage of ruthenium mass to support mass and the percentage of cobalt mass to support mass, which can further enhance catalytic activity and selectivity.

[0019] Secondly, the present invention provides a method for preparing the hydrogenation catalyst described in the first aspect of the present invention, the preparation method comprising the following steps:

[0020] (1) Mix carbon precursor, iron oxide precursor and binder, then mold and crush them in sequence, and then calcine them under a protective atmosphere to obtain iron oxide-containing carrier precursor.

[0021] (2) The carrier precursor obtained in step (1) and ferric chloride are mixed and then calcined under an activating atmosphere to obtain the carrier;

[0022] (3) The support, ruthenium-cobalt precursor solution and precipitant obtained in step (2) are mixed, and then solid-liquid separation, washing and drying are performed in sequence to obtain the catalyst precursor;

[0023] (4) The catalyst precursor obtained in step (3) is reduced to obtain a hydrogenation catalyst.

[0024] In this invention, an iron oxide precursor is first calcined under a protective atmosphere to avoid contact with oxygen, causing the iron oxide precursor to decompose and produce an iron oxide-containing support precursor. Then, the iron oxide and ferric chloride in the iron oxide-containing support precursor react to generate ferrous chloride and oxygen. The ferrous chloride and excess ferric chloride sublimate at high temperature and are carried away by the active atmosphere, resulting in an excellent pore structure. Simultaneously, the active atmosphere deposits active functional groups on the support surface. Next, the active component is loaded into the pores of the support using a co-precipitation method. The confinement of the active component by the support pores and the active functional groups on the support surface significantly enhance the catalytic activity and selectivity of the catalyst, while also extending the catalyst lifetime.

[0025] In this invention, the molding method is not particularly limited, and any molding method commonly used in the art can be adopted, such as kneading in a mixing device.

[0026] In this invention, the crushing method is not particularly limited, and any crushing method commonly used in the art can be adopted, such as an air jet mill.

[0027] In this invention, the mixing method described in step (3) is not particularly limited. It can be that the three are mixed at the same time, or that the ruthenium-cobalt precursor solution and the precipitant are added to the aqueous solution containing the carrier at the same time.

[0028] In this invention, the method of solid-liquid separation is not particularly limited and can be any solid-liquid separation method commonly used in the art, such as filtration or centrifugation.

[0029] Preferably, the carbon precursor in step (1) comprises oil-based needle coke.

[0030] Preferably, the iron oxide precursor comprises ferric nitrate and / or ferric carbonate.

[0031] Preferably, the binder comprises coal-based pitch and / or residual oil pitch.

[0032] Preferably, the mass ratio of the carbon precursor, iron oxide precursor and binder is 100:(1-30):(10-50), for example, it can be 100:1:10, 100:5:15, 100:10:20, 100:15:30, 100:20:35 or 100:25:50, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 100:(5-10):(20-40).

[0033] Preferably, the particle size of the particles obtained after crushing is ≤100μm, for example, it can be 100μm, 90μm, 95μm, 80μm or 85μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0034] Preferably, the protective atmosphere includes nitrogen.

[0035] Preferably, the roasting temperature in step (1) is 500-2000℃, for example, it can be 500℃, 600℃, 800℃, 1000℃, 1200℃, 1400℃, 1600℃, 1800℃ or 2000℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 1000-1500℃.

[0036] In this invention, it is preferable to control the calcination temperature in step (1) within a specific range so that the iron oxide precursor can be fully thermally decomposed into iron oxide, while the binder can be well combined with the carbon precursor and fully pyrolyzed into an iron oxide-containing carrier precursor with a stable structure.

[0037] Preferably, the roasting time in step (1) is 5-24h, for example, it can be 5h, 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h or 24h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 10-20h.

[0038] Preferably, the molar amount of ferric chloride in step (2) is 5-20 times the molar amount of ferric oxide in the carrier precursor, for example, it can be 5 times, 6 times, 8 times, 10 times, 12 times, 14 times, 16 times, 18 times or 20 times, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0039] In this invention, it is preferable to control the molar amount of ferric chloride to be a multiple of the molar amount of ferric oxide in the carrier precursor, so as to ensure that the ferric oxide and ferric chloride in the carrier precursor react fully, thereby achieving the pore-forming effect.

[0040] Preferably, the activating atmosphere comprises gaseous hydrocarbons.

[0041] Preferably, the gaseous hydrocarbon includes any one or a combination of at least two of methane, ethane, propane, ethylene, or propylene, wherein typical but non-limiting combinations include a combination of methane and propane or a combination of ethane and propane, preferably ethylene.

[0042] In this invention, ethylene is preferred because it has moderate thermal stability. At the calcination temperature in step (2), ethylene can slowly undergo thermal decomposition to achieve carbon modification and local coating of the pores, thereby further enhancing the activity of the support.

[0043] Preferably, the flow rate of the activating atmosphere is 100-1000 sccm, for example, it can be 100 sccm, 200 sccm, 300 sccm, 400 sccm, 500 sccm, 600 sccm, 700 sccm, 800 sccm, 900 sccm or 1000 sccm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0044] Preferably, the water content of the activating atmosphere is ≤50ppm, for example, it can be 50ppm, 40ppm, 30ppm, 20ppm or 10ppm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0045] In this invention, it is preferable to control the water content of the activation atmosphere within a specific range, which can avoid excessive water content inhibiting the reaction of ferric chloride and ferric oxide and thus avoid affecting the pore-forming effect.

[0046] Preferably, the roasting temperature in step (2) is 1000-1500℃, for example, it can be 1000℃, 1100℃, 1200℃, 1300℃, 1400℃ or 1500℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0047] In this invention, it is preferable to control the calcination temperature in step (2) within a specific range, which can promote the reaction of ferric chloride and ferric oxide to generate ferrous chloride, and allow ferrous chloride to be discharged from the system in gaseous form along with the activation gas used in the activation atmosphere.

[0048] Preferably, the roasting time in step (2) is 1-10h, for example, it can be 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h or 10h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0049] Preferably, the precipitant in step (3) includes a sodium hydroxide solution.

[0050] Preferably, the concentration of the precipitant is 0.1-1 mol / L, for example, it can be 0.1 mol / L, 0.2 mol / L, 0.4 mol / L, 0.6 mol / L, 0.8 mol / L or 1 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0051] Preferably, the ruthenium-cobalt precursor solution contains ruthenium salt and cobalt salt.

[0052] In this invention, the ruthenium salt and cobalt salt can be any ruthenium salt and cobalt salt commonly used in coprecipitation methods in the art. For example, the ruthenium salt can be ruthenium chloride, and the cobalt salt can be cobalt nitrate.

[0053] Preferably, the pH value of the mixed solution obtained after mixing in step (3) is neutral.

[0054] Preferably, the mixture in step (3) is left to stand.

[0055] Preferably, the settling temperature is 50-120℃, for example, it can be 50℃, 60℃, 70℃, 80℃, 90℃, 100℃, 110℃ or 120℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0056] Preferably, the settling time is 10-20 hours, for example, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours or 20 hours, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0057] Preferably, the drying temperature is 60-150℃, for example, it can be 60℃, 70℃, 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃ or 150℃, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0058] Preferably, the drying time is 6-24 hours, for example, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours or 24 hours, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0059] Preferably, the reducing agent used in step (4) includes hydrogen gas.

[0060] Preferably, the reduction temperature is 80-160℃, for example, it can be 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃ or 160℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 100-120℃.

[0061] Preferably, the reduction time is 2-20 hours, for example, it can be 2 hours, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours or 20 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 5-10 hours.

[0062] As a preferred embodiment of the second aspect of the present invention, the preparation method includes the following steps:

[0063] (1) A carbon precursor, an iron oxide precursor, and a binder are mixed in a mass ratio of 100:(1-30):(10-50), then shaped, crushed to a particle size ≤100μm, and then calcined at 500-2000℃ for 5-24h under a nitrogen atmosphere to obtain an iron oxide-containing carrier precursor; the carbon precursor includes oil-based needle coke, the iron oxide precursor includes ferric nitrate and / or ferric carbonate, and the binder includes coal-based pitch and / or residual oil pitch;

[0064] (2) The carrier precursor obtained in step (1) and ferric chloride are mixed, wherein the molar amount of ferric chloride is 5-20 times the molar amount of ferric oxide in the carrier precursor, and then calcined at 1000-1500℃ for 1-10h in a gaseous hydrocarbon atmosphere to obtain the carrier; wherein the gaseous hydrocarbon includes any one or a combination of at least two of methane, ethane, propane, ethylene or propylene, wherein the flow rate of the gaseous hydrocarbon is 100-1000 sccm, and the water content of the gaseous hydrocarbon is ≤50ppm;

[0065] (3) The support, ruthenium cobalt precursor solution and sodium hydroxide solution obtained in step (2) are mixed. The concentration of the sodium hydroxide solution is 0.1-1 mol / L. The pH value of the mixed solution after mixing is neutral. Then, it is allowed to stand at 50-120℃ for 10-20h. After that, solid-liquid separation and washing are performed in sequence. Then, it is dried at 60-150℃ for 6-24h to obtain the catalyst precursor.

[0066] (4) The catalyst precursor obtained in step (3) is reduced with hydrogen at 80-160°C for 2-20 hours to obtain the hydrogenation catalyst.

[0067] Thirdly, the present invention provides the use of a hydrogenation catalyst as described in the first aspect of the present invention, said hydrogenation catalyst being used in the reaction of hydrogenating unsaturated enaldehydes to prepare unsaturated enols.

[0068] The hydrogenation catalyst provided by this invention is used for the hydrogenation of unsaturated enaldehydes to prepare unsaturated enols, and is particularly suitable for the highly selective hydrogenation of citral to geraniol or nerol, or the highly selective hydrogenation of citronellol to citronellol.

[0069] Preferably, the mass of the hydrogenation catalyst accounts for 1-5% of the mass of the unsaturated aldehyde, for example, it can be 1%, 2%, 3%, 4% or 5%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0070] Preferably, the reaction temperature is 40-150℃, for example, it can be 40℃, 50℃, 60℃, 70℃, 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃ or 150℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 60-100℃.

[0071] Preferably, the reaction pressure is 1-10 MPaG, for example, it can be 1 MPaG, 2 MPaG, 3 MPaG, 4 MPaG, 5 MPaG, 6 MPaG, 7 MPaG, 8 MPaG, 9 MPaG or 10 MPaG, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 2-8 MPaG.

[0072] Preferably, the reaction time is 1-20h, for example, it can be 1h, 2h, 4h, 6h, 8h, 10h, 12h, 14h, 16h, 18h or 20h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 6-16h.

[0073] Compared with the prior art, the present invention has the following beneficial effects:

[0074] (1) The hydrogenation catalyst provided by the present invention uses active mesoporous carbon as a support and controls the preparation method of active mesoporous carbon to make it have rich mesoporous structure and activity, thereby improving its catalytic effect. The hydrogenation catalyst provided by the present invention is used for the hydrogenation of unsaturated enaldehyde to prepare unsaturated enol, and is particularly suitable for the reaction of hydrogenating citral to geraniol or nerol with high selectivity, or the reaction of hydrogenating citronellol to citronellol with high selectivity. It has high target product yield and selectivity, and good catalyst life.

[0075] (2) The hydrogenation catalyst provided by the present invention is used in the reaction of hydrogenating citral to prepare geraniol, which can make the conversion rate of citral reach more than 90.4%, and more than 98.5% under better conditions; the selectivity of geraniol can reach more than 93.7%, and more than 98.1% under better conditions. Detailed Implementation

[0076] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention.

[0077] Example 1

[0078] This embodiment provides a hydrogenation catalyst, which includes a support and an active component supported on the support. The active component is a ruthenium-cobalt alloy, and the support is active mesoporous carbon. The active mesoporous carbon has an average pore size of 100 nm, a porosity of 1.1 mL / g, and a specific surface area of ​​540 m². 2 / g, the average particle size of the active mesoporous carbon is 75μm; in the hydrogenation catalyst, ruthenium accounts for 0.1% of the support mass and cobalt accounts for 0.01% of the support mass.

[0079] This embodiment also provides a method for preparing the above-mentioned hydrogenation catalyst, the method comprising the following steps:

[0080] (1) Mixed oil-based needle coke (produced by Shandong Yida New Material Co., Ltd.), ferric nitrate (purity 99.5%, Aladdin Reagent Co., Ltd.) and coal-based pitch (produced by Shanxi Coking Group) in a kneading equipment at a mass ratio of 100:2:48, then shaped, and then crushed to an average particle size of 60μm by an air jet mill. After that, it was calcined at 1000℃ for 16h under a nitrogen atmosphere to obtain a carrier precursor containing iron oxide;

[0081] (2) The carrier precursor obtained in step (1) and ferric chloride (purity of 99%, produced by Aladdin Reagent Co., Ltd.) are mixed. The molar amount of ferric chloride is 10 times the molar amount of ferric oxide in the carrier precursor. Then, the mixture is calcined at 1000°C for 5 hours in an ethylene atmosphere (ethylene flow rate of 200 sccm, water content of 26 ppm) to obtain the carrier.

[0082] (3) Dissolve 0.02 g of ruthenium chloride (purity 98 wt%, produced by Aladdin Reagent Co., Ltd.) and 3.14 mg of cobalt nitrate (purity 99.99 wt%, produced by Aladdin Reagent Co., Ltd.) in 10 mL of deionized water to obtain a ruthenium cobalt precursor solution. Add the ruthenium cobalt precursor solution and 0.1 mol / L NaOH aqueous solution in parallel to 100 mL of aqueous solution containing 12 g of support, control the pH value to 7, and let it stand at 70 °C for 16 h after the addition is complete. Then filter it, wash the solid obtained by filtration until neutral, and then dry it at 100 °C for 6 h to obtain the catalyst precursor.

[0083] (4) The catalyst precursor obtained in step (3) is reduced with hydrogen at 100°C for 15 h to obtain the hydrogenation catalyst.

[0084] Example 2

[0085] This embodiment provides a hydrogenation catalyst, which includes a support and an active component supported on the support. The active component is a ruthenium-cobalt alloy, and the support is active mesoporous carbon. The active mesoporous carbon has an average pore size of 25 nm, a porosity of 1.8 mL / g, and a specific surface area of ​​850 m². 2 / g, the average particle size of the active mesoporous carbon is 22μm; in the hydrogenation catalyst, ruthenium accounts for 5% of the support mass and cobalt accounts for 0.5% of the support mass.

[0086] This embodiment also provides a method for preparing the above-mentioned hydrogenation catalyst, the method comprising the following steps:

[0087] (1) Mixed oil needle coke (produced by Shandong Yida New Material Co., Ltd.), iron carbonate (purity 99.5%, Aladdin Reagent Co., Ltd.) and residual oil asphalt (Dalian Hengli Petrochemical) in a kneading equipment at a mass ratio of 100:15:30, then shaped, and then crushed to an average particle size of 10 μm by an air jet mill. After that, it was calcined at 500℃ for 5 h under a nitrogen atmosphere to obtain a carrier precursor containing iron oxide.

[0088] (2) The carrier precursor obtained in step (1) and ferric chloride (purity of 99%, produced by Aladdin Reagent Co., Ltd.) are mixed. The molar amount of ferric chloride is 5 times the molar amount of ferric oxide in the carrier precursor. Then, the mixture is calcined at 1200°C for 10 hours in an ethylene atmosphere (ethylene flow rate of 100 sccm, water content of 4 ppm) to obtain the carrier.

[0089] (3) Dissolve 0.85g of ruthenium chloride (purity 98wt%, produced by Aladdin Reagent Co., Ltd.) and 0.157g of cobalt nitrate (purity 99.99wt%, produced by Aladdin Reagent Co., Ltd.) in 10mL of deionized water to obtain a ruthenium cobalt precursor solution. Add the ruthenium cobalt precursor solution and 0.1mol / L NaOH aqueous solution in parallel to 100mL of aqueous solution containing 12g of support, control the pH value to 7, and let it stand at 90℃ for 10h after the addition is complete. Then filter it, wash the solid obtained by filtration until neutral, and then dry it at 150℃ for 12h to obtain the catalyst precursor.

[0090] (4) The catalyst precursor obtained in step (3) is reduced with hydrogen at 160°C for 3 hours to obtain the hydrogenation catalyst.

[0091] Example 3

[0092] This embodiment provides a hydrogenation catalyst, which includes a support and an active component supported on the support. The active component is a ruthenium-cobalt alloy, and the support is active mesoporous carbon. The active mesoporous carbon has an average pore size of 145 nm, a porosity of 0.4 mL / g, and a specific surface area of ​​350 m². 2 / g, the average particle size of the active mesoporous carbon is 50μm; in the hydrogenation catalyst, ruthenium accounts for 10% of the support mass and cobalt accounts for 5% of the support mass.

[0093] This embodiment also provides a method for preparing the above-mentioned hydrogenation catalyst, the method comprising the following steps:

[0094] (1) Mix oil-based needle coke (produced by Shandong Yida New Material Co., Ltd.), ferric carbonate (purity 99.5%, Aladdin Reagent Co., Ltd.) and coal-based pitch (produced by Shanxi Coking Group) in a kneading equipment at a mass ratio of 100:30:50, then shape it, and then crush it to an average particle size of 50μm using an air jet mill. After that, it is calcined at 2000℃ for 5h under a nitrogen atmosphere to obtain a carrier precursor containing iron oxide.

[0095] (2) The carrier precursor obtained in step (1) and ferric chloride (purity of 99%, produced by Aladdin Reagent Co., Ltd.) are mixed. The molar amount of ferric chloride is 20 times the molar amount of ferric oxide in the carrier precursor. Then, the mixture is calcined at 1500°C for 1 hour in an ethylene atmosphere (ethylene flow rate of 1000 scmm, water content of 50 ppm) to obtain the carrier.

[0096] (3) Dissolve 1.70 g of ruthenium chloride (purity 98 wt%, produced by Aladdin Reagent Co., Ltd.) and 1.57 g of cobalt nitrate (purity 99.99 wt%, produced by Aladdin Reagent Co., Ltd.) in 10 mL of deionized water to obtain a ruthenium cobalt precursor solution. Add the ruthenium cobalt precursor solution and 0.8 mol / L NaOH aqueous solution in parallel to 100 mL of aqueous solution containing 12 g of support, control the pH value to 7, and let it stand at 120 °C for 10 h after the addition is complete. Then filter it, wash the filtered solid until neutral, and dry it at 150 °C for 6 h to obtain the catalyst precursor.

[0097] (4) The catalyst precursor obtained in step (3) is reduced with hydrogen at 160°C for 20 h to obtain the hydrogenation catalyst.

[0098] Example 4

[0099] This embodiment provides a method for preparing a hydrogenation catalyst. The only difference between this method and Example 1 is that ethylene in step (2) is replaced with methane.

[0100] Example 5

[0101] This embodiment provides a method for preparing a hydrogenation catalyst. The only difference between this method and Example 1 is that ethylene in step (2) is replaced with propane.

[0102] Example 6

[0103] This embodiment provides a method for preparing a hydrogenation catalyst. The only difference between this method and Example 1 is that ethylene in step (2) is replaced with propylene.

[0104] Example 7

[0105] This embodiment provides a method for preparing a hydrogenation catalyst. The only difference between this method and Example 1 is that the calcination temperature in step (2) is 800°C.

[0106] Example 8

[0107] This embodiment provides a method for preparing a hydrogenation catalyst. The only difference between this method and Example 1 is that the calcination temperature in step (2) is 1800°C.

[0108] Example 9

[0109] This embodiment provides a method for preparing a hydrogenation catalyst. The only difference between this method and Example 1 is that the molar amount of ferric chloride in step (2) is twice the molar amount of ferric oxide in the carrier precursor.

[0110] Example 10

[0111] This embodiment provides a method for preparing a hydrogenation catalyst. The only difference between this method and Example 1 is that the molar amount of ferric chloride in step (2) is 25 times the molar amount of ferric oxide in the carrier precursor.

[0112] Comparative Example 1

[0113] This comparative example provides a method for preparing a hydrogenation catalyst. The only difference between this method and Example 1 is that the support is commercially available mesoporous carbon with an average particle size of 180 μm and an average pore size of 120 nm.

[0114] Comparative Example 2

[0115] This comparative example provides a method for preparing a hydrogenation catalyst. The difference between this method and Example 1 is that step (2) is replaced by mixing the support precursor obtained in step (1) and ferric chloride, calcining at 1200°C for 5 hours, then introducing ethylene, and continuing to calcine for 5 hours in an ethylene atmosphere to obtain the support.

[0116] The catalytic performance of the hydrogenation catalysts in Examples 1-10 and Comparative Examples 1-2 was evaluated:

[0117] In a 500 mL hydrogenation reactor, 5 g of hydrogenation catalyst was first added, followed by 100 g of citral. The pressure vessel was then sealed, and the reactor was purged three times each with nitrogen and hydrogen. Heating and stirring were then initiated. When the temperature reached 80 °C, hydrogen gas was introduced to a pressure of 8 MPa, and the reaction was maintained at this temperature for 15 h until completion. The concentration of the target product was detected using gas chromatography, and the conversion rate and selectivity of geraniol were calculated. The results are shown in Table 1.

[0118] The gas chromatograph used was an Agilent 7890 with a Wax column. The test conditions included: an injection port temperature of 300℃; a split ratio of 50:1; a carrier gas flow rate of 52.8 mL / min; a temperature program of 150℃ for 10 min, then increasing to 260℃ at a rate of 10℃ / min and holding for 5 min; and a detector temperature of 280℃.

[0119] Table 1

[0120] Conversion rate / % Geraniol Selectivity / % Example 1 99.4 99.3 Example 2 99.0 98.1 Example 3 98.5 98.6 Example 4 96.2 94.4 Example 5 95.3 94.6 Example 6 94.1 94.5 Example 7 92.3 95.5 Example 8 90.4 93.7 Example 9 94.8 94.1 Example 10 95.4 95.5 Comparative Example 1 90.7 87.4 Comparative Example 2 92.8 89.3

[0121] The following points can be observed from Table 1:

[0122] (1) As can be seen from the data of Examples 1-10, the hydrogenation catalyst provided by the present invention can achieve a conversion rate of more than 90.4% for the hydrogenation of citral to prepare geraniol, and can achieve a conversion rate of more than 98.5% under better conditions; the selectivity of geraniol can reach more than 93.7%, and can reach more than 98.1% under better conditions.

[0123] (2) A comprehensive comparison of the data from Examples 1 and 4-6 shows that the only difference between Examples 4-6 and Example 1 is that ethylene is replaced by methane, propane and propylene respectively. The conversion rate and selectivity in Example 1 are significantly higher than those in Examples 4-6. Therefore, it can be seen that the present invention preferably controls the activation atmosphere to be ethylene, which can further improve the activity and selectivity of the catalyst.

[0124] (3) A comprehensive comparison of the data from Example 1 and Example 7-8 shows that the only difference between Example 7-8 and Example 1 is that the calcination temperature in step (2) is not within the preferred range of the present invention. The conversion rate and selectivity in Example 1 are significantly higher than those in Example 7-8. Therefore, it can be seen that the present invention preferably controls the calcination temperature in step (2) to further improve the activity and selectivity of the catalyst.

[0125] (4) A comprehensive comparison of the data from Examples 1 and 9-10 shows that the only difference between Examples 9-10 and Example 1 is that the molar amount of ferric chloride relative to the molar amount of iron oxide in the carrier precursor is not within the preferred range of the present invention. The conversion rate and selectivity in Example 1 are significantly higher than those in Examples 9-10. Therefore, the present invention preferably controls the molar amount of ferric chloride relative to the molar amount of iron oxide in the carrier precursor, which can further promote the full reaction of iron oxide, thereby improving the activity and selectivity of the catalyst.

[0126] (5) A comprehensive comparison of the data from Example 1 and Comparative Examples 1-2 shows that the only difference between Comparative Example 1 and Example 1 is that commercially available mesoporous carbon is used as the support, and the only difference between Comparative Example 2 and Example 1 is that calcination is performed first in step (2) and then activation is performed. The results show that the conversion rate and selectivity in Example 1 are significantly higher than those in Comparative Examples 1-2. This is because the commercially available mesoporous carbon used in Comparative Example 1 contains more and larger pores and fewer defects in the pore structure, making it difficult to form a good interaction with the active components, resulting in more side reactions and a decrease in selectivity. In contrast, in Comparative Example 2, the support is formed under conditions without ethylene, which prevents the formation of effective carbon modification and coating on the surface during the pore-forming process. As a result, there are fewer surface defects, and it is difficult to form an effective synergistic effect with the active components, leading to a decrease in catalytic activity, especially selectivity. This indicates that the hydrogenation catalyst provided by the present invention has high catalytic activity and selectivity, can avoid the generation of by-products, and improve catalyst life.

[0127] In summary, the hydrogenation catalyst provided by this invention has a good service life, is suitable for the hydrogenation of unsaturated enaldehydes to prepare unsaturated enols, and has a high yield and selectivity of the target product.

[0128] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. The use of a hydrogenation catalyst, characterized in that, The hydrogenation catalyst includes a support and an active component supported on the support; The active component includes a ruthenium-cobalt alloy; The carrier comprises active mesoporous carbon, which is prepared by the following method: mixing a carbon precursor, an iron oxide precursor and a binder, then sequentially molding and crushing them, followed by calcination under a protective atmosphere to obtain an iron oxide-containing carrier precursor; calcining the carrier precursor and ferric chloride under an activating atmosphere to obtain the active mesoporous carbon. The carbon precursor includes oil-based needle coke; The iron oxide precursor includes ferric nitrate and / or ferric carbonate; The binder includes coal-based pitch and / or residual oil pitch; The activating atmosphere includes gaseous hydrocarbons; The gaseous hydrocarbons include any one or a combination of at least two of methane, ethane, propane, ethylene, or propylene; The hydrogenation catalyst is used in the reaction of hydrogenating unsaturated enaldehydes to prepare unsaturated enols.

2. The use according to claim 1, characterized in that, The average pore size of the active mesoporous carbon is 20-150 nm.

3. The use according to claim 1, characterized in that, The porosity of the active mesoporous carbon is 0.4-2 mL / g.

4. The use according to claim 1, characterized in that, The specific surface area of ​​the active mesoporous carbon is 300-1000 m². 2 / g.

5. The use according to claim 1, characterized in that, The average particle size of the active mesoporous carbon is 10-100 μm.

6. The use according to claim 1, characterized in that, In the hydrogenation catalyst, ruthenium accounts for 0.1-10% of the support mass.

7. The use according to claim 6, characterized in that, In the hydrogenation catalyst, ruthenium accounts for 1-5% of the mass of the support.

8. The use according to claim 1, characterized in that, In the hydrogenation catalyst, cobalt accounts for 0.01-5% of the mass of the support.

9. The use according to claim 8, characterized in that, In the hydrogenation catalyst, cobalt accounts for 0.1-1% of the mass of the support.

10. The use according to claim 1, characterized in that, The preparation method of the hydrogenation catalyst includes the following steps: (1) Mix carbon precursor, iron oxide precursor and binder, then mold and crush them in sequence, and then calcine them under a protective atmosphere to obtain iron oxide-containing carrier precursor; (2) The carrier precursor obtained in step (1) and ferric chloride are mixed and then calcined under an activating atmosphere to obtain the carrier; (3) The support, ruthenium-cobalt precursor solution and precipitant obtained in step (2) are mixed, and then solid-liquid separation, washing and drying are performed in sequence to obtain the catalyst precursor; (4) The catalyst precursor obtained in step (3) is reduced to obtain a hydrogenation catalyst.

11. The use according to claim 1, characterized in that, The mass ratio of the carbon precursor, iron oxide precursor and binder is 100:(1-30):(10-50).

12. The use according to claim 11, characterized in that, The mass ratio of the carbon precursor, iron oxide precursor and binder is 100:(5-10):(20-40).

13. The use according to claim 10, characterized in that, The particle size of the particles obtained after crushing is ≤100μm.

14. The use according to claim 10, characterized in that, The protective atmosphere includes nitrogen.

15. The use according to claim 10, characterized in that, The roasting temperature in step (1) is 500-2000℃.

16. The use according to claim 15, characterized in that, The roasting temperature in step (1) is 1000-1500℃.

17. The use according to claim 10, characterized in that, The roasting time in step (1) is 5-24 hours.

18. The use according to claim 17, characterized in that, The roasting time in step (1) is 10-20 hours.

19. The use according to claim 10, characterized in that, The molar amount of ferric chloride in step (2) is 5-20 times the molar amount of ferric oxide in the carrier precursor.

20. The use according to claim 1, characterized in that, The gaseous hydrocarbon is ethylene.

21. The use according to claim 1, characterized in that, The flow rate of the activating atmosphere is 100-1000 sccm.

22. The use according to claim 1, characterized in that, The water content of the activating atmosphere is ≤50ppm.

23. The use according to claim 10, characterized in that, The roasting temperature in step (2) is 1000-1500℃.

24. The use according to claim 10, characterized in that, The roasting time in step (2) is 1-10 hours.

25. The use according to claim 10, characterized in that, The precipitant in step (3) includes a sodium hydroxide solution.

26. The use according to claim 10, characterized in that, The concentration of the precipitant is 0.1-1 mol / L.

27. The use according to claim 10, characterized in that, The ruthenium-cobalt precursor solution contains ruthenium salt and cobalt salt.

28. The use according to claim 10, characterized in that, The pH value of the mixed solution obtained after mixing in step (3) is neutral.

29. The use according to claim 10, characterized in that, After mixing in step (3), the mixture should be left to stand.

30. The use according to claim 29, characterized in that, The settling temperature is 50-120℃.

31. The use according to claim 29, characterized in that, The settling time is 10-20 hours.

32. The use according to claim 10, characterized in that, The drying temperature is 60-150℃.

33. The use according to claim 10, characterized in that, The drying time is 6-24 hours.

34. The use according to claim 10, characterized in that, The reducing agent used in step (4) includes hydrogen gas.

35. The use according to claim 10, characterized in that, The reduction temperature is 80-160℃.

36. The use according to claim 35, characterized in that, The reduction temperature is 100-120℃.

37. The use according to claim 10, characterized in that, The restoration time is 2-20 hours.

38. The use according to claim 37, characterized in that, The restoration time is 5-10 hours.

39. The use according to claim 1, characterized in that, The hydrogenation catalyst accounts for 1-5% of the mass of the unsaturated enaldehyde.

40. The use according to claim 1, characterized in that, The reaction temperature is 40-150℃.

41. The use according to claim 40, characterized in that, The reaction temperature is 60-100℃.

42. The use according to claim 1, characterized in that, The reaction is carried out at a pressure of 1-10 MPaG.

43. The use according to claim 42, characterized in that, The reaction is carried out at a pressure of 2-8 MPaG.

44. The use according to claim 1, characterized in that, The reaction time is 1-20 hours.

45. The use according to claim 44, characterized in that, The reaction time is 6-16 hours.