A Cu-based catalyst for aldehyde hydrogenation and its preparation method and application

Abstract

The present invention provides a kind of aldehyde hydrogenation Cu-based catalyst and its preparation method and application. The composition of the catalyst is Cu-M / SiO2-Al2O3, the content of active component Cu is 20-40wt%, and the content of auxiliary agent M is 1-5wt%. The catalyst preparation method includes: after the active component is mixed with a dispersant, a supported catalyst is obtained by a co-current coprecipitation method, wherein the introduction of a carrier with a large specific surface area can improve the active group dispersion, and the addition of a metal auxiliary agent can effectively promote the interaction (SMSI) of the metal carrier, which is conducive to suppressing its sintering and agglomeration during the reaction, enhancing catalytic activity, and reducing the loss of metal in liquid phase reaction. The catalyst of the present invention reduces the alcoholysis of silicon by adopting a composite carrier, protects the catalyst skeleton from being destroyed, prolongs the catalyst life, and has good performance in aldehyde hydrogenation reaction.

Description

Technical Field

[0001] The invention relates to the field of catalysts, and in particular to an aldehyde hydrogenation Cu-based catalyst and a preparation method and application thereof. Background Art

[0002] Alcohol compounds are an important chemical product, such as butanol, 2-methylbutanol, 1,3-propylene glycol, neopentyl glycol, etc., which are widely used in the fields of fine chemicals and new chemical materials. They are mainly used in esters, plasticizers, solvents, pharmaceutical intermediates, flavors and fragrances, and polyester materials (polypropylene terephthalate). Aldehyde hydrogenation is one of the important means to prepare the above alcohols. At present, Cu catalysts are widely used in the field of aldehyde hydrogenation.

[0003] The main catalysts for aldehyde hydrogenation reactions include precious metal Pd, Raney Ni, Cu-based catalysts, etc. For Cu-based catalysts, Cu-Cr catalysts were first used, but due to environmental issues, they were gradually replaced by Cu-Zn-M series catalysts. The latter exhibits advantages such as relatively low pollution and high mechanical strength. Many manufacturers at home and abroad have conducted research, including UCC in the United States, ICI in the United Kingdom, Hoechst in Germany, and China Petroleum Petrochemical Research Institute. In terms of catalyst preparation and molding, co-precipitation and tableting methods are mostly used. The Cu catalysts used in aldehyde hydrogenation also include Raney type, Cu / SiO2 and other series of catalysts.

[0004] Patent CN114054033A reports a Cu-based catalyst for gas-phase aldehyde hydrogenation. The Cu-Zn catalyst was prepared by two acid-base precipitations and applied to the hydrogenation of octenal and n-butyraldehyde. The catalyst has high selectivity, but is a bulk catalyst with a high metal content, and the active components are easily sintered during the reaction.

[0005] Patent CN112264044A reports a new type of Raney Cu catalyst, which improves the synergistic effect with metal additives by adding organic matter, improves the catalyst reaction activity, and is applied to the hydrogenation reaction of 3-hydroxypropanal with good activity. However, this method requires high-temperature molten metal to prepare the catalyst, which consumes a lot of energy.

[0006] Patent CN111318280A discloses a Cu-M-SiO2 catalyst prepared by an ammonia evaporation method, which promotes the dispersion of silica sol by adding alcohol during the preparation process, thereby facilitating the dispersion of active components and improving the low-temperature activity of the catalyst. However, the M additive in the catalyst is a precious metal, and the production cost is relatively high.

[0007] According to the existing technology, Cu-based catalysts have the problems of high metal content, poor mechanical strength of bulk catalysts, and easy breakage of the skeleton during application. Especially in liquid-phase aldehyde hydrogenation such as kettle and trickle bed reactors, the weak interaction between Cu-based catalysts and the carrier will lead to the loss of metal active components. At the same time, in the Cu / SiO2 system, the presence of alcohol will cause alcoholysis of the Si skeleton, resulting in a short catalyst life. It is challenging to solve the above problems by using a simple and effective catalyst synthesis method. Summary of the invention

[0008] The present invention aims at the deficiencies in the prior art and provides a Cu-based catalyst for aldehyde hydrogenation and a preparation method and application thereof. The catalyst provided by the present invention is a supported catalyst obtained by mixing an active component Cu, an auxiliary agent and a dispersant, and then subjecting the mixture to a co-current coprecipitation method. The catalyst of the present invention utilizes the steric hindrance of an organic dispersant and the introduction of a carrier with a large specific surface area to effectively improve the dispersion of the active component and enhance the reaction activity; in addition, the addition of a metal auxiliary agent and alumina is conducive to improving the strong interaction between the metal and the carrier, effectively inhibiting Cu sintering and the alcohol and water resistance of the catalyst, and improving the life of the catalyst.

[0009] To achieve the above object, the present invention is specifically implemented through the following technical solutions:

[0010] A method for preparing a Cu-based catalyst for aldehyde hydrogenation comprises the following steps:

[0011] (1) Mixing the soluble salt of Cu and the additive M with the dispersant, stirring until completely dissolved, to obtain aqueous solution A, and then mixing deionized water and industrial SiO2 powder, stirring and dispersing evenly, to obtain mixed liquid B;

[0012] (2) 20-30 wt% alkaline silica sol, aqueous solution A and precipitant are pumped into mixed liquid B in parallel, the coprecipitation temperature is 60-90° C., the pH value is 7-8, and after the solution is added, it is aged for 2-12 hours under the above conditions, and then filtered, washed, dried, and calcined at 350-400° C. to obtain a catalyst precursor;

[0013] (3) The catalyst precursor is kneaded with pseudo-boehmite, nitric acid solution and an extrusion aid, and then extruded into a mold, and then dried and calcined at 350-400° C. to obtain a Cu-based aldehyde hydrogenation catalyst having a composition of Cu-M / SiO2-Al2O3.

[0014] In the preparation method of the aldehyde hydrogenation Cu-based catalyst of the present invention, the composition is preferably Cu-M / SiO2-Al2O3, and the content ranges of the various components are as follows: the content of Cu is 20-40wt%, the content of M is 1-5wt%, the content of SiO2 is 20-40wt%, and the content of Al2O3 is 20-40wt%.

[0015] Preferably, the soluble salt of Cu described in the present invention is one or more of copper nitrate, copper acetate, and copper sulfate, and the additive M is one or more of the nitrates of Ni, Mn, Zr, Ce, Y, and Bi.

[0016] Preferably, the dispersant of the present invention is one or more of PEG-400, PEG-600, PEG-800, and PEG-1000.

[0017] Further preferably, the industrial SiO2 powder of the present invention is added in an amount of 1-5wt% (based on the total weight of the catalyst) and has a specific surface area of ​​350-400m 2 / g, pore volume is 0.5-0.6cm 3 / g.

[0018] The precipitant in step 2) of the present invention is one or more of ammonia water, ammonium carbonate, ethanolamine, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine.

[0019] After extrusion molding, the catalyst of the present invention is one of a clover, a four-leaf clover and a cylinder with a diameter of 2-4 mm.

[0020] The present invention also provides a Cu-based catalyst for aldehyde hydrogenation prepared by the above preparation method.

[0021] The present invention further provides an application of the above-mentioned aldehyde hydrogenation Cu-based catalyst in the hydrogenation reaction of propionaldehyde, butyraldehyde, 2-methylbutyraldehyde, 3-methylbutyraldehyde, 3-hydroxypropionaldehyde or hydroxypivalaldehyde.

[0022] In a further preferred application, the evaluation conditions of the aldehyde hydrogenation reaction are as follows:

[0023] (1) Reaction temperature: 80-160°C;

[0024] (2) Reaction pressure: 1-5 MPa;

[0025] (3) Reaction gas ratio: H2 / aldehyde = 5-20 / 1 (m / m);

[0026] (4) Reaction liquid volume space velocity: 0.8-2h -1 .

[0027] The main beneficial effects of the preparation method and application of the aldehyde hydrogenation Cu-based catalyst provided by the present invention are as follows:

[0028] (1) Utilizing the interaction between the active component Cu and the dispersant and precipitant, the metal dispersion is promoted due to the presence of steric hindrance during the precipitation process. The addition of industrial large specific surface area SiO2 promotes the dispersion of active sites and enhances the reaction activity.

[0029] (2) The addition of metal additives enhances the interaction between Cu and the carrier, improves the catalyst's anti-sintering ability, and reduces the loss of Cu in the liquid phase reaction.

[0030] (3) Adding Al2O3 to prepare a supported catalyst during the extrusion molding process can effectively improve the catalyst's resistance to alcoholysis and water resistance in the liquid phase aldehyde hydrogenation reaction and extend its service life.

[0031] (4) The catalyst synthesis steps are simple and easy to operate, which is conducive to industrial scale-up production.

[0032] In summary, the aldehyde hydrogenation Cu-based catalyst provided by the present invention can provide higher reaction activity and product selectivity, and the catalyst life is improved, and has good application prospects. Specific implementation methods

[0033] The following examples illustrate the preparation method and application of the aldehyde hydrogenation Cu-based catalyst provided by the present invention, but the present invention is not limited thereto.

[0034] Example 1

[0035] Dissolve 37.75g Cu(NO3)2·3H2O, 12.40g Ni(NO3)2·6H2O, 5g PEG-400 in 200ml deionized water, stir and mix until completely dissolved, and obtain aqueous solution A. Add 100ml deionized water and 0.5g industrial SiO2 powder to another beaker and stir evenly to obtain mixed liquid B. Then, aqueous solution A, 65g alkaline silica sol (30wt%), and precipitant ammonia water are pumped into mixed liquid B in parallel, and the coprecipitation temperature is controlled to be 60℃, and the pH value is 7-8. After the solution is added, it is aged for 2h under the above conditions. After filtering, washing, and drying, a catalyst precursor is obtained. Add 23.3g pseudo-boehmite, 33g nitric acid solution, and an extrusion aid to the catalyst precursor, and extrude it after sufficient kneading to obtain a clover-shaped product with a diameter of 2-4mm, and then dry it and calcine it at 350℃ to obtain a Cu-Ni / SiO2-Al2O3 catalyst.

[0036] Example 2

[0037] Dissolve 56.63g Cu(NO3)2·3H2O, 16.27g Mn(NO3)2 aqueous solution (50wt%), and 5g PEG-600 in 200ml deionized water, stir and mix well to obtain aqueous solution A. Add 100ml deionized water and 1g industrial SiO2 powder to another beaker and stir well to obtain mixed liquid B. Then, aqueous solution A, 46.67g alkaline silica sol (30wt%), and precipitant ammonia water are pumped into mixed liquid B in parallel. The coprecipitation temperature is 60℃, the pH value is 7-8, and the solution is aged for 4h under the above conditions after addition. After filtering, washing, and drying, the catalyst precursor is obtained. Add 23.3g of pseudo-boehmite, 33g of nitric acid solution and an extrusion aid to the catalyst precursor, knead thoroughly and extrude it into a clover-shaped product with a diameter of 2-4mm. Dry it and calcine it at 350°C to obtain a Cu-Mn / SiO2-Al2O3 catalyst.

[0038] Example 3

[0039] Dissolve 75.5g Cu(NO3)2·3H2O, 5.59g Zr(NO3)4·5H2O, and 5g PEG-800 in 200ml deionized water, stir and mix well to obtain aqueous solution A. Add 100ml deionized water and 1g industrial SiO2 powder to another beaker and stir well to obtain mixed liquid B. Then, aqueous solution A, 46.67g alkaline silica sol (30wt%), and precipitant ammonia water are pumped into mixed liquid B in parallel. The coprecipitation temperature is 70℃, the pH value is 7-8, and the solution is aged for 8h under the above conditions after the addition is completed. After filtering, washing, and drying, a catalyst precursor is obtained. Add 20g pseudo-boehmite, 33g nitric acid solution, and an auxiliary agent to the catalyst precursor, and extrude and shape it after sufficient kneading to obtain a clover-shaped product with a diameter of 2-4mm, and then dry it and calcine it at 350℃ to obtain a Cu-Zr / SiO2-Al2O3 catalyst.

[0040] Example 4

[0041] Dissolve 75.5g Cu(NO3)2·3H2O, 5.59g Zr(NO3)4·5H2O, and 5g PEG-800 in 200ml deionized water, stir and mix well to obtain aqueous solution A. Add 100ml deionized water and 1g industrial SiO2 powder to another beaker and stir well to obtain mixed liquid B. Then, aqueous solution A, 46.67g alkaline silica sol (30wt%), and precipitant ammonium carbonate are pumped into mixed liquid B in parallel. The coprecipitation temperature is 70°C, the pH value is 7-8, and the solution is aged for 8h under the above conditions after the addition is completed. After filtering, washing, and drying, a catalyst precursor is obtained. Add 20g pseudo-boehmite, 33g nitric acid solution, and an extrusion aid to the catalyst precursor, and extrude it after sufficient kneading to obtain a clover-shaped product with a diameter of 2-4mm, and then dry it and calcine it at 350°C to obtain a Cu-Zr / SiO2-Al2O3 catalyst.

[0042] Example 5

[0043] Dissolve 37.75g Cu(NO3)2·3H2O, 4.67g Ce(NO3)3·6H2O, and 5g PEG-800 in 200ml deionized water, stir and mix well to obtain aqueous solution A. Add 100ml deionized water and 2.5g industrial SiO2 powder to another beaker and stir well to obtain mixed liquid B. Then, aqueous solution A, 58.30g alkaline silica sol (30wt%), and precipitant ammonia water are pumped into mixed liquid B in parallel. The coprecipitation temperature is 80℃, the pH value is 7-8, and the solution is aged for 12h under the above conditions after addition. After filtering, washing, and drying, the catalyst precursor is obtained. Add 24.67g of pseudo-boehmite, 33g of nitric acid solution and an extrusion aid to the catalyst precursor, knead thoroughly and extrude it into a four-leaf clover shape with a diameter of 2-4mm. Then dry it and calcine it at 350℃ to obtain a Cu-Ce / SiO2-Al2O3 catalyst.

[0044] Example 6

[0045] Dissolve 37.75g Cu(NO3)2·3H2O, 4.67g Ce(NO3)3·6H2O, and 5g PEG-800 in 200ml deionized water, stir and mix well to obtain aqueous solution A. Add 100ml deionized water and 2.5g industrial SiO2 powder to another beaker and stir well to obtain mixed liquid B. Then, aqueous solution A, 58.30g alkaline silica sol (30wt%), and precipitant ethanolamine are pumped into mixed liquid B in parallel. The coprecipitation temperature is 80℃, the pH value is 7-8, and the solution is aged for 12h under the above conditions after addition. After filtering, washing, and drying, the catalyst precursor is obtained. Add 24.67g of pseudo-boehmite, 33g of nitric acid solution and an extrusion aid to the catalyst precursor, knead thoroughly and extrude it into a four-leaf clover shape with a diameter of 2-4mm. Then dry it and calcine it at 350℃ to obtain a Cu-Ce / SiO2-Al2O3 catalyst.

[0046] Example 7

[0047] Dissolve 37.75g Cu(NO3)2·3H2O, 4.67g Ce(NO3)3·6H2O, and 5g PEG-800 in 200ml deionized water, stir and mix well to obtain aqueous solution A. Add 100ml deionized water and 2.5g industrial SiO2 powder to another beaker and stir well to obtain mixed liquid B. Then, aqueous solution A, 58.30g alkaline silica sol (30wt%), and precipitant diethylenetriamine are pumped into mixed liquid B in parallel. The coprecipitation temperature is 80℃, the pH value is 7-8, and the solution is aged for 12h under the above conditions after addition. After filtering, washing, and drying, the catalyst precursor is obtained. Add 24.67g of pseudo-boehmite, 33g of nitric acid solution and an auxiliary agent to the catalyst precursor, knead thoroughly and extrude to obtain a four-leaf clover shape with a diameter of 2-4mm, then dry and calcine at 350°C to obtain a Cu-Ce / SiO2-Al2O3 catalyst.

[0048] Example 8

[0049] Dissolve 37.75g Cu(NO3)2·3H2O, 4.67g Ce(NO3)3·6H2O, and 5g PEG-800 in 200ml deionized water, stir and mix well to obtain aqueous solution A. Add 100ml deionized water and 2.5g industrial SiO2 powder to another beaker and stir well to obtain mixed liquid B. Then, aqueous solution A, 58.30g alkaline silica sol (30wt%), and precipitant triethylenetetramine are pumped into mixed liquid B in parallel. The coprecipitation temperature is 80℃, the pH value is 7-8, and the solution is aged for 12h under the above conditions after addition. After filtering, washing, and drying, the catalyst precursor is obtained. Add 24.67g of pseudo-boehmite, 33g of nitric acid solution and an auxiliary agent to the catalyst precursor, knead thoroughly and extrude to obtain a four-leaf clover shape with a diameter of 2-4mm, then dry and calcine at 350°C to obtain a Cu-Ce / SiO2-Al2O3 catalyst.

[0050] Example 9

[0051] Dissolve 56.63g Cu(NO3)2·3H2O, 2.17g Y(NO3)3·6H2O, and 5g PEG-800 in 200ml deionized water, stir and mix well to obtain aqueous solution A. Add 100ml deionized water and 1g industrial SiO2 powder to another beaker and stir well to obtain mixed liquid B. Then, aqueous solution A, 46.67g alkaline silica sol (30wt%), and precipitant ammonia water are pumped into mixed liquid B in parallel. The coprecipitation temperature is 80℃, the pH value is 7-8, and the solution is aged for 4h under the above conditions after the addition is completed. After filtering, washing, and drying, a catalyst precursor is obtained. Add 26g pseudo-boehmite, 33g nitric acid solution, and an auxiliary agent to the catalyst precursor, and extrude it after sufficient kneading to obtain a four-leaf clover with a diameter of 2-4mm, and then dry it and calcine it at 350℃ to obtain a Cu-Y / SiO2-Al2O3 catalyst.

[0052] Example 10

[0053] Dissolve 75.5g Cu(NO3)2·3H2O, 1.17g Bi(NO3)3·5H2O, and 5g PEG-1000 in 200ml deionized water, stir and mix well to obtain aqueous solution A. Add 100ml deionized water and 2.5g industrial SiO2 powder to another beaker and stir well to obtain mixed liquid B. Then, aqueous solution A, 56.67g alkaline silica sol (30wt%), and precipitant ammonia water are pumped into mixed liquid B in parallel. The coprecipitation temperature is 90℃, the pH value is 7-8, and the solution is aged for 8h under the above conditions after the addition is completed. After filtering, washing, and drying, a catalyst precursor is obtained. Add 13.33g pseudo-boehmite, 33g nitric acid solution, and an extrusion aid to the catalyst precursor, and extrude it after sufficient kneading to obtain a cylindrical shape with a diameter of 2-4mm, and then dry it and calcine it at 350℃ to obtain a Cu-Bi / SiO2-Al2O3 catalyst.

[0054] Embodiment 11

[0055] The performance of the catalyst was evaluated in a 200 mL adiabatic micro fixed bed reactor with a catalyst loading of 30 mL. The catalyst was reduced at 300 °C for 6 h under hydrogen conditions. The evaluation results are shown in Table 1.

[0056] (1) The reaction conditions for propionaldehyde hydrogenation are: reaction temperature 110°C, 20 wt% propionaldehyde-propanol solution feed, liquid hourly space velocity 1.0 h -1 , H2 / aldehyde molar ratio 12, reaction pressure 3.0MPa.

[0057] (2) The reaction conditions for butyraldehyde hydrogenation are: reaction temperature 110°C, 20 wt% butyraldehyde-butanol solution feed, liquid hourly space velocity 1.0 h -1 , H2 / aldehyde molar ratio 12, reaction pressure 3.0MPa.

[0058] (3) The reaction conditions for the hydrogenation of 2-methylbutanal are: reaction temperature 110°C, 20 wt% 2-methylbutanal-2-methylbutanol solution feed, liquid hourly space velocity 1.0 h -1 , H2 / aldehyde molar ratio 10, reaction pressure 3.0MPa.

[0059] (4) The reaction conditions for hydrogenation of 3-methylbutanal are: reaction temperature 110°C, 20 wt% 3-methylbutanal-3-methylbutanol solution feed, liquid hourly space velocity 1.0 h -1 , H2 / aldehyde molar ratio 10, reaction pressure 3.0MPa.

[0060] (5) The reaction conditions for the hydrogenation of 3-hydroxypropanal are:

[0061] The first stage: reaction temperature 70 ° C, 10 wt% aqueous solution feed, liquid hourly space velocity 1.2h-1 , H2 / aldehyde molar ratio 7, reaction pressure 5.0MPa.

[0062] The second stage: reaction temperature 110 ° C, 10 wt% aqueous solution feed, liquid hourly space velocity 1.0 h -1 , H2 / aldehyde molar ratio 7, reaction pressure 5.0MPa.

[0063] (6) The reaction conditions for the hydrogenation of hydroxypivaldehyde are: reaction temperature 120°C, reaction pressure 3.5 MPa, 20 wt% ethanol solution feed, liquid hourly space velocity 1.0 h -1 , H2 / aldehyde molar ratio 10, space velocity 1.0h -1 .

[0064] Table 1 Evaluation of aldehyde hydrogenation catalytic reaction performance

[0065]

Claims

1. A method for preparing a Cu-based catalyst for aldehyde hydrogenation, characterized in that: The steps include: (1) Mix the soluble salt of Cu and additive M with the dispersant, stir until completely dissolved to obtain aqueous solution A, then mix deionized water and industrial SiO2 powder, stir and disperse evenly to obtain mixed liquid B; (2) 20-30wt% alkaline silica sol, aqueous solution A and precipitant are pumped into mixed liquid B in parallel, the co-precipitation temperature is 60-90°C, the pH value is 7-8, and after the solution is added, it is aged for 2-12h under the above conditions, and then filtered, washed, dried, and calcined at 350-400°C to obtain a catalyst precursor; (3) kneading the catalyst precursor with pseudo-boehmite, nitric acid solution and extrusion aid, extruding and then drying, and calcining at 350-400° C. to obtain a Cu-based aldehyde hydrogenation catalyst; the structure of the Cu-based aldehyde hydrogenation catalyst is Cu-M / SiO2-Al2O3; The auxiliary agent M is one or more of the nitrates of Ni, Mn, Zr, Ce, Y and Bi; The dispersant is one or more of PEG-400, PEG-600, PEG-800, and PEG-1000; The precipitant is one or more of ammonia water, ammonium carbonate, ethanolamine, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine; The industrial SiO2 powder is added in an amount of 1-5wt% and has a specific surface area of ​​350-400 m 2 / g, pore volume is 0.5-0.6 cm 3 / g; The content ranges of the various components are as follows: Cu content is 20-40wt%, M content is 1-5wt%, SiO2 content is 20-40wt%, and Al2O3 content is 20-40wt%.

2. The method for preparing a Cu-based aldehyde hydrogenation catalyst according to claim 1, characterized in that: The soluble salt of Cu in step (1) is one or more of copper nitrate, copper acetate and copper sulfate.

3. The method for preparing a Cu-based catalyst for aldehyde hydrogenation according to claim 1, wherein the catalyst after extrusion molding in step (2) is one of a clover, a four-leaf clover, and a cylinder with a diameter of 2-4 mm.

4. A Cu-based catalyst for aldehyde hydrogenation prepared according to the preparation method according to any one of claims 1 to 3.

5. Use of the aldehyde hydrogenation Cu-based catalyst according to claim 4 in the hydrogenation reaction of propionaldehyde, butyraldehyde, 2-methylbutyraldehyde, 3-methylbutyraldehyde, 3-hydroxypropionaldehyde or hydroxypivalaldehyde.

6. The use according to claim 5, characterized in that: The reaction temperature of the hydrogenation reaction is 80-160 °C, the reaction pressure is 1-5 MPa, the reaction gas ratio is H2 / aldehyde molar ratio = 5-20 / 1, and the reaction liquid volume space velocity is 0.8-2 h -1 .

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