Supported zirconium-based catalysts, methods for their preparation, and uses thereof

Abstract

This invention discloses a supported zirconium-based catalyst, its preparation method, and its application. It includes a zirconium-based support and a noble metal supported on the zirconium-based support. The zirconium-based support includes one or more of a zirconium-based composite oxide support and a zirconium-based metal-organic framework material. The zirconium-based composite oxide support includes a composite of zirconium oxide and other oxides, and the other oxides include oxides of one or more elements selected from Si, P, Ce, and Mg. The above-mentioned supported zirconium-based catalyst increases the interaction between the supported noble metal and the support by introducing Si, P, Ce, or Mg into the zirconium-based support to adjust the electron cloud density or oxygen vacancy concentration of the zirconium-based support. By using a zirconium-based metal-organic framework material with regular channels to support the noble metal, reactants and products can diffuse relatively quickly and smoothly, thereby avoiding excessive side reactions and carbon deposition caused by excessive retention of reaction intermediates or products.

Description

Technical Field

[0001] This invention relates to the field of catalytic materials technology, and in particular to supported zirconium-based catalysts, their preparation methods, and applications. Background Technology

[0002] Supported catalysts consist of a support and a catalytically active metal supported on the support. Traditional methods for preparing supported catalysts often employ impregnation, where a salt solution of the active metal is simply mixed with a powdered support, adsorbed, dried, and calcined. The salt solution of the active metal migrates to the surface of the support and forms metal particles during subsequent high-temperature calcination. The metal particles prepared by traditional impregnation are generally bonded to the support by van der Waals forces or simple electrostatic adsorption. Due to the large surface energy of the metal particles and the low bonding strength between the metal particles and the support, the metal particles in the catalyst undergo surface migration and agglomeration, leading to a decrease in the number of participating active metal atoms, rapid catalyst deactivation, and low catalytic efficiency. Summary of the Invention

[0003] Therefore, it is necessary to provide a supported zirconium-based catalyst, its preparation method, and its application, with the aim of improving the catalytic efficiency of the catalyst.

[0004] In one aspect, the present invention provides a supported zirconium-based catalyst, comprising a zirconium-based support and a noble metal supported on the zirconium-based support;

[0005] The zirconium-based support includes one or more of zirconium-based composite oxide supports and zirconium-based metal-organic framework materials. The zirconium-based composite oxide support includes a composite of zirconium oxide and other oxides, wherein the other oxides include oxides of one or more elements selected from Si, P, Ce and Mg.

[0006] The aforementioned supported zirconium-based catalysts, by introducing one or more elements from Si, P, Ce, and Mg into the zirconium-based support, adjust the electron cloud density or oxygen vacancy concentration of the zirconium-based support, thereby increasing the interaction between the supported noble metal and the support. This allows the noble metal to effectively combine with the zirconium-based support, slowing down the migration and aggregation of the noble metal on the surface of the zirconium-based support, thus improving the overall stability of the supported catalyst and maintaining effective catalytic activity during long-term operation. By using a zirconium-based metal-organic framework material with regular channels to support the noble metal, the reactants and products in the catalytic reaction of the supported zirconium-based catalyst can diffuse relatively quickly and smoothly, reducing the residence time of reaction intermediates or products in the channels, thereby avoiding excessive side reactions and carbon deposition caused by excessive retention of reaction intermediates or products to a certain extent.

[0007] In one embodiment, the zirconium-based composite oxide support satisfies one or more of the following conditions:

[0008] (1) The chemical formula of the zirconium-based composite oxide support is ZrM x O y M includes one or more of Si, P, Ce and Mg, where 0 < x ≤ 10 and 2 ≤ y ≤ 50;

[0009] (2) The average particle size of the zirconium-based composite oxide support is 0.1 μm to 1.0 μm.

[0010] In one embodiment, the zirconium-based metal-organic framework material comprises a zirconium metal cluster and an organic ligand coordinated with the zirconium metal cluster;

[0011] The zirconium metal clusters include one or more of Zr6O8, Zr8O6, ZrO6, ZrO7, and ZrO8;

[0012] The organic ligands include one or more of terephthalic acid and its derivatives, biphenyl dicarboxylic acid and its derivatives, naphthalene dicarboxylic acid and its derivatives, 1,3,5-tris(carboxyphenyl)benzene and its derivatives, 1,2,4,5-tetra(4-carboxyphenyl)benzene and its derivatives, neu-tetra(4-carboxyphenyl)porphyrin and its derivatives, and 1,3,5-benzenetricarboxylic acid and its derivatives.

[0013] In one embodiment, the zirconium-based metal-organic framework material satisfies one or more of the following conditions:

[0014] (1) The specific surface area of ​​the zirconium-based metal-organic framework material is 600 m². 2 / g~800m 2 / g;

[0015] (2) The average pore size of the zirconium-based metal-organic framework material is 1 nm to 5 nm;

[0016] (2) The pore volume of the zirconium-based metal-organic framework material is 0.5 cm³. 3 / g~1cm 3 / g.

[0017] In one embodiment, the noble metal has a mass content of 0.1 wt% to 1.0 wt% relative to the zirconium-based support.

[0018] Another aspect of the present invention provides a method for preparing a supported zirconium-based catalyst, comprising the following steps:

[0019] A mixed suspension is obtained by mixing a noble metal salt, a zirconium-based support, a complexing agent, and a solvent.

[0020] The mixed suspension was separated into solid and liquid components to obtain a solid catalyst precursor;

[0021] The solid catalyst precursor was calcined to obtain the supported zirconium-based catalyst.

[0022] The above-mentioned method for preparing supported zirconium-based catalysts involves using a complexing agent to disperse and encapsulate noble metal ions in a solvent, forming a complex. The functional groups in the complexing agent interact with the hydroxyl groups on the surface of the zirconium-based support, thereby indirectly fixing the noble metals onto the surface of the zirconium-based support. During the subsequent calcination process, the complexing agent isolates the dispersed noble metals, slowing down the tendency of noble metals to agglomerate during calcination and ensuring good dispersion of the noble metals.

[0023] In one embodiment, a complexing agent is also added to the mixed suspension, the complexing agent including one or more of citric acid, β-cyclodextrin, ethylenediamine, hexadecyltrimethylammonium chloride, and ethylenediaminetetraacetic acid.

[0024] In one embodiment, the noble metal salt, the zirconium-based support, the complexing agent, and the solvent are mixed to satisfy one or more of the following conditions:

[0025] (1) The mass ratio of the complexing agent to the noble metal salt is 23:1 to 3:1;

[0026] (2) The mass content of the noble metal salt relative to the zirconium-based support is 0.17wt%~1.7wt%.

[0027] In another aspect, the present invention provides a method for preparing diisobutyl ketone, comprising the following steps:

[0028] Using the above-mentioned supported zirconium-based catalyst or the supported zirconium-based catalyst prepared by the above method, acetone is used as a raw material to catalyze the synthesis of diisobutyl ketone.

[0029] The above-described method for preparing diisobutyl ketone (DIK) utilizes a zirconium oxide support to form a composite oxide support and a zirconium-based metal-organic framework material with regular channels as a support. This enables continuous and efficient catalysis of the dehydration condensation of acetone to form an isopropylidene acetone intermediate, followed by catalytic hydrogenation of the intermediate to form DK. This catalyst lowers the energy barrier of the key rate-limiting step (synthesis of the isopropylidene acetone intermediate) in the catalytic synthesis of DK, thereby improving the acetone conversion rate and DK selectivity.

[0030] In one embodiment, the reaction temperature for synthesizing the diisobutyl ketone is 140°C to 160°C, the reaction pressure is 0.9 to 1.1 atmospheres, and the feed space velocity of the acetone is 1.00 h⁻¹.-1 ~3.00h -1 The molar ratio of hydrogen to acetone is 0.3 to 0.5.

[0031] In the above method for preparing diisobutyl ketone, the conversion rate of acetone is ≥90%, the selectivity of diisobutyl ketone is ≥55%, and the selectivity of the byproduct methyl isobutyl ketone is ≤25%. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the synthetic route of diisobutyl ketone in one embodiment;

[0033] Figure 2 The image shows the detection results of diisobutyl ketone in Example 1;

[0034] Figure 3 The image shows the detection results of the isopropylidene acetone intermediate in Example 1. Detailed Implementation

[0035] To facilitate understanding of the present invention, a more complete description will be given below with reference to relevant embodiments. Preferred embodiments of the invention are shown below. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that a thorough and complete understanding of the disclosure of the invention will be achieved.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0037] Supported catalysts exhibit high catalytic efficiency due to the nanoscale particle size and large specific surface area of ​​the supported active metal particles, resulting in a large number of active metal atoms participating in the catalytic reaction. However, due to the high surface free energy of the active metal particles, supported catalysts tend to aggregate during preparation and catalytic synthesis. This aggregation tendency poses a significant challenge to the catalytic efficiency and stability of supported catalysts. The key to solving this problem is establishing a strong interaction between the active metal particles and the support, which can effectively prevent the aggregation of active metal particles.

[0038] Traditionally, catalysts for the catalytic synthesis of diisobutyl ketone from acetone are mostly palladium-supported zirconium oxide catalysts obtained by simple impregnation. During the catalytic synthesis process, the acid sites of the catalyst are prone to carbon deposition, leading to rapid deactivation. Therefore, the selectivity for diisobutyl ketone is poor and the operating cycle is short.

[0039] A supported zirconium-based catalyst includes a zirconium-based support and a noble metal supported on the zirconium-based support;

[0040] Zirconium-based supports include one or more of zirconium-based composite oxide supports and zirconium-based metal-organic framework materials. Zirconium-based composite oxide supports include complexes of zirconium oxide and other oxides, which include oxides of one or more elements selected from Si, P, Ce and Mg.

[0041] The aforementioned supported zirconium-based catalysts, by introducing one or more elements from Si, P, Ce, and Mg into the zirconium-based support, adjust the electron cloud density or oxygen vacancy concentration of the zirconium-based support, thereby increasing the interaction between the supported noble metal and the zirconium-based support. This allows the noble metal to effectively bind with the zirconium-based support, slowing down the migration and aggregation of the noble metal on the surface of the zirconium-based support, thus improving the overall stability of the supported catalyst and maintaining effective catalytic activity during long-term operation. By using a zirconium-based metal-organic framework material with regular channels to support the noble metal, the reactants and products in the catalytic reaction of the supported zirconium-based catalyst can diffuse relatively quickly and smoothly, reducing the residence time of reaction intermediates or products in the channels. This, to a certain extent, avoids excessive side reactions and carbon deposition caused by excessive retention of reaction intermediates or products.

[0042] In one embodiment, the zirconium-based composite oxide support has the chemical formula ZrM. x O y M includes one or more of Si, P, Ce and Mg, where 0 < x ≤ 10 and 2 ≤ y ≤ 50.

[0043] Furthermore, the zirconium-based composite oxide support includes ZrP x O y ZrCe x O y ZrMg x O y ZrSi x O y Where 0 < x ≤ 10, 2 ≤ y ≤ 50.

[0044] In one embodiment, the molar ratio of zirconium oxide to other oxides is 1:0.1 to 1:10.

[0045] In one embodiment, the average particle size of the zirconium-based composite oxide support is 0.1 μm to 10 μm.

[0046] In one embodiment, the zirconium-based metal-organic framework material comprises a zirconium metal cluster and an organic ligand coordinated with the zirconium metal cluster; the zirconium metal cluster comprises one or more of Zr6O8, Zr8O6, ZrO6, ZrO7, and ZrO8; the organic ligand comprises one or more of terephthalic acid and its derivatives, biphenyl dicarboxylic acid and its derivatives, naphthalene dicarboxylic acid and its derivatives, 1,3,5-tris(carboxyphenyl)benzene and its derivatives, 1,2,4,5-tetra(4-carboxyphenyl)benzene and its derivatives, methyl-tetra(4-carboxyphenyl)porphyrin and its derivatives, pyrazole-3,5-dicarboxylic acid and its derivatives, and 1,3,5-benzenetricarboxylic acid and its derivatives.

[0047] In one embodiment, the precious metal includes one or more of palladium and platinum.

[0048] A method for preparing a supported zirconium-based catalyst includes the following steps:

[0049] A mixed suspension is obtained by mixing a noble metal salt, a zirconium-based support, and a solvent.

[0050] The mixed suspension was separated into solid and liquid phases to obtain a solid catalyst precursor;

[0051] The solid catalyst precursor was calcined to obtain a supported zirconium-based catalyst.

[0052] The above-mentioned method for preparing supported zirconium-based catalysts involves using a complexing agent to disperse and encapsulate noble metal ions in a solvent, forming a complex. The functional groups in the complexing agent interact with the hydroxyl groups on the surface of the zirconium-based support, thereby indirectly fixing the noble metals onto the surface of the zirconium-based support. During the subsequent calcination process, the complexing agent isolates the dispersed noble metals, slowing down the tendency of noble metals to agglomerate during calcination and ensuring good dispersion of the noble metals.

[0053] In one embodiment, a complexing agent is also added to the mixed suspension, the complexing agent including one or more of citric acid, β-cyclodextrin, ethylenediamine, hexadecyltrimethylammonium chloride and ethylenediaminetetraacetic acid.

[0054] In one embodiment, the noble metal salt includes one or more of palladium chloride, palladium nitrate, palladium sulfate, palladium acetate, palladium acetylacetonate, platinum chloride, platinum nitrate, platinum sulfate, platinum acetate, and platinum acetylacetonate.

[0055] In one embodiment, a noble metal salt, a zirconium-based support, and a solvent are mixed to obtain a mixed suspension. A complexing agent is also added to the mixed suspension. The process includes the following steps.

[0056] The precious metal salt is dissolved in a solvent, and the pH value is adjusted to 3-4 using concentrated hydrochloric acid with a mass fraction of 36%-38% to obtain a precious metal solution; the complexing agent is dissolved in a solvent to obtain a complexing agent solution.

[0057] The complexing agent solution was added dropwise to the noble metal liquid to obtain the first mixture; the zirconium-based support was placed in the first mixture.

[0058] In one embodiment, the concentration of the noble metal salt in the noble metal solution is 0.001 mol / L to 0.01 mol / L.

[0059] In one embodiment, the concentration of the complexing agent in the complexing agent solution is 0.018 mol / L to 0.085 mol / L.

[0060] In one embodiment, the volume ratio of the noble metal solution to the noble metal salt solution is 2:1 to 1:2.

[0061] In one embodiment, solid-liquid separation of the mixed suspension includes the following steps:

[0062] The liquid in the mixed suspension is removed by rotary evaporation.

[0063] In one embodiment, after obtaining the solid catalyst precursor and before calcining the solid catalyst precursor, the following steps are also included:

[0064] The solid catalyst precursor was dried at 70℃~90℃ for 5h~10h.

[0065] In one embodiment, the solid catalyst precursor is calcined at a temperature of 400°C to 600°C for 3 to 5 hours.

[0066] In one embodiment, the zirconium-based composite oxide support includes a zirconium-phosphorus composite oxide support, ZrP. x O y Zirconium-cerium composite oxide carrier ZrCe x O y Zirconium-magnesium composite oxide support ZrMg x O y ZrSi composite oxide carrier x O y One or more of them.

[0067] In one embodiment, the zirconium-phosphorus composite oxide carrier ZrP x O y The preparation method includes the following steps:

[0068] Zirconium salt is dissolved in a solvent to obtain a zirconium salt solution; diammonium hydrogen phosphate is dissolved in a solvent to obtain a diammonium hydrogen phosphate solution.

[0069] The diammonium hydrogen phosphate solution was added dropwise to the zirconium salt solution, and the mixture was stirred for 3 to 5 hours after the addition was completed to obtain the second mixture.

[0070] The second mixture was separated into solid and liquid phases to obtain a zirconium-phosphorus composite oxide precursor.

[0071] The zirconium-phosphorus composite oxide precursor was calcined at 350℃~450℃ for 4h~8h.

[0072] In one embodiment, the zirconium content in the zirconium salt solution is 1.2 wt% to 6.5 wt%, and the phosphorus content in the diammonium hydrogen phosphate solution is 0.45 wt% to 8.5 wt%.

[0073] In one embodiment, the volume ratio of zirconium salt solution to diammonium hydrogen phosphate solution is 1:2 to 2:1.

[0074] In one embodiment, the zirconium-cerium composite oxide carrier ZrCe x O y The preparation method includes the following steps:

[0075] Zirconium salt, cerium salt and solvent are mixed to obtain a zirconium-cerium salt solution;

[0076] Add ammonia solution to zirconium and cerium salt solution until the pH value is 9-10, heat to 90℃-110℃ and let stand for 2h-4h to obtain the third mixture. Remove heating and let the third mixture cool and stand to separate into layers.

[0077] After the solid in the third mixture settles to the bottom of the third mixture, the clear liquid at the top of the third mixture is removed to obtain the solid. The solid is washed with deionized water until the washing liquid is neutral to obtain the zirconium-cerium composite oxide precursor.

[0078] The zirconium-cerium composite oxide precursor was calcined at 500℃~600℃ for 4h~8h.

[0079] In one embodiment, the mass ratio of zirconium salt to cerium salt is 0.18:1 to 18:1.

[0080] In one embodiment, the ammonia solution contains 5.0 mol / L of ammonia. -1 ~17.5 mol L -1 .

[0081] In one embodiment, the zirconium-magnesium composite oxide carrier ZrMg x O y The preparation method includes the following steps:

[0082] Zirconium salt, magnesium salt and deionized water are mixed to obtain a zirconium-magnesium salt solution;

[0083] Add ammonia solution to zirconium magnesium salt solution until the pH value is 9~11, let stand at 20℃~30℃ for 3h~5h, then boil and reflux at 90℃~110℃ for 2h~4h to obtain the fourth mixture;

[0084] Cool and let the fourth mixture stand until the solid in the fourth mixture settles to the bottom. Remove the clear liquid at the top of the fourth mixture and wash the bottom of the fourth mixture with deionized water until neutral. Separate the solid and liquid to obtain the zirconium magnesium composite oxide precursor.

[0085] The zirconium-magnesium composite oxide precursor was calcined at 500℃~600℃ for 3h~5h.

[0086] In one embodiment, the mass ratio of zirconium salt to magnesium salt is 0.26:1 to 26:1.

[0087] In one embodiment, the ammonia solution contains 5.0 mol / L of ammonia. -1 ~17.5 mol L -1 .

[0088] In one embodiment, the zirconium-silicon composite oxide carrier ZrSi x O y The preparation method includes the following steps:

[0089] Zirconium salts are dissolved in a solvent to obtain a zirconium salt solution; organosilicon compounds are dissolved in a solvent to obtain an organosilicon solution.

[0090] A zirconium salt solution was added to an organosilicon solution, and a copolymer was added to obtain a fifth mixture.

[0091] The fifth mixture was subjected to a hydrothermal reaction at 60℃~120℃ for 20h~28h, and then naturally cooled to 10℃~30℃. The liquid in the fifth mixture was removed to obtain a solid. The solid was washed with deionized water and ethanol until the washing solution was neutral to obtain the zirconium silicon composite oxide precursor.

[0092] The zirconium-silicon composite oxide precursor was calcined at 450℃~550℃ for 4h~8h.

[0093] In one embodiment, the zirconium-based metal-organic framework material includes one or more of MOF-808, PCN-222, MOF-545, MOF-802, UiO-66, UiO-67, and UiO-68.

[0094] In one embodiment, the preparation method of zirconium-based metal-organic framework material UiO-66 includes the following steps:

[0095] Zirconium salt, terephthalic acid, hydrochloric acid and N,N-dimethylformamide were mixed to obtain a reaction solution;

[0096] The reaction solution was subjected to hydrothermal reaction at 100℃~140℃ for 20h~28h, and then naturally cooled to 10℃~30℃ to obtain the sixth mixture. The sixth mixture was centrifuged to obtain the solid in the sixth mixture. The solid was washed successively with N,N-dimethylformamide, ethanol and water, and then ground to 40 mesh~60 mesh. The solid was then placed in a vacuum dryer at 30℃~80℃ for 8h~12h to obtain UiO-66.

[0097] In one embodiment, the zirconium salt includes one or more of zirconium nitrate, zirconium chloride, zirconium sulfate, and zirconium oxychloride.

[0098] In one embodiment, the cerium salt includes one or more of cerium chloride, cerium sulfate, and cerium nitrate.

[0099] In one embodiment, the magnesium salt includes one or more of magnesium chloride, magnesium sulfate, and magnesium nitrate.

[0100] In one embodiment, the organosilicon compound includes tetraethyl orthosilicate.

[0101] In one embodiment, the copolymer comprises a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer.

[0102] In one embodiment, the solvent includes one or more of water, ethanol, toluene, and chloroform.

[0103] Please see Figure 1 One embodiment of this application provides a method for preparing diisobutyl ketone, comprising the following steps:

[0104] Using the above-mentioned supported zirconium-based catalyst or the supported zirconium-based catalyst prepared by the above method, acetone is used as a raw material to catalyze the synthesis of diisobutyl ketone.

[0105] The above-described method for preparing diisobutyl ketone (DIK) utilizes a zirconium oxide support to form a composite oxide support and a zirconium-based metal-organic framework material with regular channels as a support. This enables continuous and efficient catalysis of the dehydration condensation of acetone to form an isopropylidene acetone intermediate, followed by catalytic hydrogenation of the intermediate to form DK. This catalyst lowers the energy barrier of the key rate-limiting step (synthesis of the isopropylidene acetone intermediate) in the catalytic synthesis of DK, thereby improving the acetone conversion rate and DK selectivity.

[0106] In one embodiment, the reaction temperature for synthesizing diisobutyl ketone was 140°C to 160°C, the reaction pressure was 0.9 to 1.1 atmospheres, and the acetone feed space velocity was 1.00 h⁻¹. -1 ~3.00h-1 The molar ratio of hydrogen to acetone is 0.3 to 0.5. As an example, the reaction temperature can be 140°C, 145°C, 150°C, 155°C, 160°C, or any two of the above values, for example, 145°C to 155°C. As an example, the reaction time can be 700 h, 710 h, 720 h, 730 h, 740 h, 750 h, or any two of the above values, for example, 720 h to 740 h. As an example, the reaction pressure can be 0.9 atm, 1 atm, 1.1 atm, or any two of the above values, for example, 1 to 1.1 atm. As an example, the feed space velocity of acetone can be 1.00 h⁻¹. -1 1.50h -1 2.00h -1 2.50h -1 3.00h -1 Or within the range formed by any two of the above values, for example, 1.50h -1 ~2.50h -1 As an example, the molar ratio of hydrogen to acetone can be 0.3, 0.35, 0.4, 0.45, 0.5, or any two of the above values, for example, 0.35 to 0.45.

[0107] In the above method for preparing diisobutyl ketone, the conversion rate of acetone is ≥90%, the selectivity of diisobutyl ketone is ≥55%, and the selectivity of the byproduct methyl isobutyl ketone is ≤25%.

[0108] In one embodiment, the supported zirconium-based composite oxide powder catalyst is stamped into sheets with an aspect ratio of 1:3 to 2:2; as an example, the aspect ratio can be 1:3, 1:2, 2:3, 2:2 or any two of the above values.

[0109] In one embodiment, a supported zirconium-based composite oxide catalyst is packed in the middle section of a fixed-bed reactor, with the upper and lower sections of the reactor filled with inert ceramic balls. Hydrogen gas is introduced into the reactor at a temperature of 280°C to 320°C for 1 to 2 hours. After the hydrogen introduction is completed, the temperature of the reactor is lowered to 150°C to 230°C, and acetone is introduced to react for 0 to 1000 hours.

[0110] The following are specific examples.

[0111] Example 1

[0112] S1. Preparation of the zirconium-phosphorus composite oxide support. 100 mL of a 35 wt% ammonium dihydrogen phosphate aqueous solution was added dropwise to 200 mL of a 23 wt% zirconium dichloride aqueous solution. After the addition was complete, the mixture was stirred for 4 h. The zirconium-phosphorus composite oxide precursor was obtained by filtration. This precursor was dried at 120 °C for 6 h, and then calcined at 400 °C for 5 h in air to obtain the zirconium-phosphorus composite oxide support Zr₂P₃O₃. 11 .

[0113] S2. Preparation of palladium-supported zirconium-phosphorus composite oxide catalyst. 0.083 g of palladium chloride was weighed and dissolved in 100 mL of deionized water. The pH was adjusted to 3-4 with 38% hydrochloric acid to obtain solution A. 0.98 g of citric acid was dissolved in 60 mL of deionized water to obtain solution B. Solution B was added dropwise to solution A, and the mixture was stirred for 30 min to obtain the first mixed solution. 50.0 g of the zirconium-phosphorus composite oxide support obtained in step S1 was weighed and impregnated in 160 mL of the first mixed solution for 120 min. The liquid in the first mixed solution was removed by rotary evaporation at 60 °C to obtain the catalyst precursor. The catalyst precursor was dried at 80 °C for 6 h. The dried catalyst precursor was calcined at 500 °C for 4 h in air to obtain the palladium-supported zirconium-phosphorus composite oxide catalyst.

[0114] S3. Acetone-catalyzed synthesis of diisobutyl ketone. The palladium-supported zirconium-phosphorus composite oxide catalyst obtained in step S3 was pressed into sheets with a diameter of 2.5 mm and a thickness of 1.0 mm. The catalyst sheets were packed into the middle section of the reactor, and the upper and lower sections of the reactor were filled with inert ceramic balls. Nitrogen gas was introduced into the reactor for 20 min. Hydrogen gas was then introduced into the reactor, and the reactor temperature was raised to 300 °C to activate the catalyst for 2 h. The reactor temperature was then lowered to 150 °C, and acetone was introduced into the reactor to carry out the reaction at an acetone feed space velocity of 2.00 h⁻¹. -1 The molar ratio of hydrogen to acetone is 0.4, and the reaction pressure is 1 standard atmosphere.

[0115] Figure 2 The detection results of the target product diisobutyl ketone were obtained by qualitative analysis using gas chromatography-mass spectrometry in Example 1. Figure 3 The results are from the qualitative analysis of isopropylidene acetone, a key intermediate in the reaction, using gas chromatography-mass spectrometry in Example 1.

[0116] Example 2

[0117] The preparation method of Example 2 is basically the same as that of Example 1, except that: a zirconium-cerium composite oxide support is used instead of the zirconium-phosphorus composite oxide support in Example 1, and 0.28g of ethylenediamine is used instead of 0.98g of citric acid.

[0118] Right now:

[0119] S1. Preparation of zirconium-cerium composite oxide support. 128.9 g of zirconium dichloride and 43.4 g of cerium nitrate were added to 1000 mL of deionized water, and 200 mL of 10 mol / L precipitate was added dropwise while stirring. -1 An ammonia solution was heated to 100°C and allowed to stand for 3 hours to obtain a third mixture. Heating was removed, and the third mixture was allowed to cool naturally to 25°C ± 5°C. The solid in the third mixture settled to the bottom. The clear liquid at the top of the third mixture was removed to obtain a solid. The solid was washed with deionized water until the washing liquid was neutral to obtain a zirconium-cerium composite oxide precursor. The zirconium-cerium composite oxide precursor was dried at 100°C for 12 hours, and then calcined at 550°C for 4 hours in air to obtain a zirconium-cerium composite oxide support, Zr₄CeO₂. 10 .

[0120] S2. Preparation of palladium-supported zirconium-cerium composite oxide catalyst. 0.083 g of palladium chloride was weighed and dissolved in 100 mL of deionized water. The pH was adjusted to 3-4 with 38% hydrochloric acid to obtain solution A. 0.28 g of ethylenediamine was dissolved in 60 mL of deionized water to obtain solution B. Solution B was added dropwise to solution A, and the mixture was stirred for 30 min to obtain the first mixed solution. 50 g of the zirconium-cerium composite oxide support obtained in step S1 was weighed and impregnated in 160 mL of the first mixed solution for 120 min. The liquid in the first mixed solution was removed by rotary evaporation at 60 °C to obtain the catalyst precursor. The catalyst precursor was dried at 80 °C for 6 h. The dried catalyst precursor was calcined at 500 °C for 4 h in air to obtain the palladium-supported zirconium-cerium composite oxide catalyst.

[0121] The remaining steps are the same as in Example 1.

[0122] Example 3

[0123] The preparation method of Example 3 is basically the same as that of Example 1, except that: a zirconium-magnesium composite oxide support is used instead of the zirconium-phosphorus composite oxide support in Example 1, and 0.37 g of hexadecyltrimethylammonium chloride is used instead of 0.98 g of citric acid;

[0124] Right now:

[0125] S1. Preparation of zirconium-magnesium composite oxide support. 128.9 g of zirconium dichloride and 12.0 g of magnesium sulfate were added to 1000 mL of deionized water, and 200 mL of 10 mol / L precipitate was added dropwise while stirring. -1An ammonia solution was prepared and allowed to stand at 25℃±5℃ for 3 hours, followed by boiling and reflux at 100℃ for 3 hours to obtain a fourth mixture. The fourth mixture was allowed to cool naturally to 25℃±5℃, and the solid in the fourth mixture settled to the bottom. The clear liquid at the top of the fourth mixture was removed to obtain a solid. The solid was washed with deionized water until the washing liquid was neutral to obtain a zirconium-magnesium composite oxide precursor. The zirconium-magnesium composite oxide precursor was dried at 100℃ for 12 hours, and the dried zirconium-magnesium composite oxide precursor was calcined at 550℃ for 4 hours in air to obtain a zirconium-magnesium composite oxide Zr4MgO9 support.

[0126] S2. Preparation of palladium-supported zirconium-magnesium composite oxide catalyst. 0.083 g of palladium chloride was weighed and dissolved in 100 mL of deionized water. The pH was adjusted to 3-4 with 38% hydrochloric acid to obtain solution A. 0.37 g of hexadecyltrimethylammonium chloride was dissolved in 60 mL of deionized water to obtain solution B. Solution B was added dropwise to solution A, and the mixture was stirred for 30 min to obtain the first mixed solution. 50 g of the zirconium-magnesium composite oxide support obtained in step S1 was weighed and impregnated in 160 mL of the first mixed solution for 120 min. The liquid in the first mixed solution was removed by rotary evaporation at 60 °C to obtain the catalyst precursor. The catalyst precursor was dried at 80 °C for 6 h. The dried catalyst precursor was calcined at 500 °C for 4 h in air to obtain the palladium-supported zirconium-magnesium composite oxide catalyst.

[0127] The remaining steps are the same as in Example 1.

[0128] Example 4

[0129] The preparation method of Example 4 is basically the same as that of Example 1, except that: zirconium-silicon composite oxide carrier is used instead of zirconium-phosphorus composite oxide carrier in Example 1, and 1.92 g of β-cyclodextrin is used instead of 0.98 g of citric acid.

[0130] Right now:

[0131] S1. Preparation of the zirconium-silicon composite oxide support. 30 mL of a 30 wt% zirconium dichloride ethanol solution was added to 30 mL of a 21.7 wt% tetraethyl orthosilicate ethanol solution, along with 0.88 g of a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer. The mixture was stirred at 25℃±5℃ for 24 h to obtain a fifth mixture. This fifth mixture was subjected to a hydrothermal reaction at 60℃~120℃ for 20~28 h, and then naturally cooled to 10℃~30℃. Solid-liquid separation was performed to obtain the solid in the fifth mixture. The solid was washed with deionized water and ethanol until the washings were neutral to obtain the zirconium-silicon composite oxide precursor. The zirconium-silicon composite oxide precursor was dried at 80℃ for 12 h, and then calcined at 500℃ for 5 h in air to obtain the zirconium-silicon composite oxide support ZrSiO4.

[0132] S2. Preparation of palladium-supported zirconium-silicon composite oxide catalyst. 0.083 g of palladium chloride was weighed and dissolved in 100 mL of deionized water. The pH was adjusted to 3-4 with 38% hydrochloric acid to obtain solution A. 1.92 g of β-cyclodextrin was dissolved in 60 mL of deionized water to obtain solution B. Solution B was added dropwise to solution A, followed by stirring to obtain the first mixture. 50 g of the zirconium-silicon composite oxide support obtained in step S1 was weighed and impregnated in 160 mL of the first mixture for 120 min. The liquid in the first mixture was removed by rotary evaporation at 60 °C to obtain the catalyst precursor. The catalyst precursor was dried at 80 °C for 6 h. The dried catalyst precursor was calcined at 500 °C for 4 h in air to obtain the palladium-supported zirconium-silicon composite oxide catalyst.

[0133] The remaining steps are the same as in Example 1.

[0134] Example 5

[0135] The preparation method of Example 5 is basically the same as that of Example 1, except that: UiO-66 carrier is used instead of zirconium phosphate composite oxide carrier in Example 1, and 0.68g of ethylenediaminetetraacetic acid is used instead of 0.98g of citric acid.

[0136] Right now:

[0137] Preparation of S1 and UiO-66 carriers. 32.8 g of zirconium chloride and 23.2 g of terephthalic acid were dissolved in 1200 mL of N,N-dimethylformamide, and 14 mL of 36 wt% hydrochloric acid was added to obtain a reaction solution. The reaction solution was subjected to a hydrothermal reaction at 120 °C for 24 h, and then naturally cooled to 25 °C ± 5 °C to obtain a sixth mixture. The sixth mixture was centrifuged to obtain the solid. The solid was washed successively with N,N-dimethylformamide, ethanol, and water, and then ground to 40-60 mesh. The solid was then dried at 30-60 °C for 8-12 h to obtain UiO-66, with a specific surface area of ​​693.02 m². 2 / g, average pore size is 3.57nm, pore volume is 0.77cm³. 3 / g.

[0138] S2. Preparation of palladium-supported UiO-66 catalyst. 0.083 g of palladium chloride was weighed and dissolved in 100 mL of deionized water. Concentrated hydrochloric acid (38% by mass) was added to adjust the pH to 3-4, yielding solution A. 0.68 g of ethylenediaminetetraacetic acid was dissolved in 10 mL of deionized water, yielding solution B. Solution B was added dropwise to solution A, followed by stirring, to obtain the first mixed solution. 50 g of the zirconium-silicon composite oxide support obtained in step S1 was weighed and impregnated in 110 mL of the first mixed solution for 120 min. The liquid in the first mixed solution was removed by rotary evaporation at 60 °C, yielding the catalyst precursor. The catalyst precursor was dried at 80 °C for 6 h. The dried catalyst precursor was calcined at 500 °C for 4 h in air to obtain the palladium-supported UiO-66 catalyst.

[0139] Example 6

[0140] The preparation method of Example 6 is basically the same as that of Example 1, except that the complexing agent in step S2 is omitted.

[0141] Right now:

[0142] S2. Preparation of palladium-supported zirconium-phosphorus composite oxide catalyst. 0.083 g of palladium chloride was weighed and dissolved in 100 mL of deionized water to obtain a palladium chloride solution. 50 g of the zirconium-phosphorus composite oxide support obtained in step S1 was weighed and impregnated in 100 mL of the palladium chloride solution for 120 min. The liquid was removed by rotary evaporation at 60 °C to obtain the catalyst precursor. The catalyst precursor was dried at 80 °C for 6 h. The dried catalyst precursor was calcined at 500 °C for 4 h to obtain the palladium-supported zirconium-phosphorus composite oxide catalyst.

[0143] Comparative Example 1

[0144] The preparation method of Comparative Example 1 is basically the same as that of Example 1, except that zirconium oxide is used instead of zirconium phosphate composite oxide support. Specifically, in S1, a commercially available zirconium oxide with a specific surface area of ​​10 m² is used. 2 / g~50 m 2 Zirconia with an average particle size of 0.1~1.0 μm per g.

[0145] Comparative Example 2

[0146] The preparation method of Comparative Example 2 is basically the same as that of Example 1, except that a sulfonic acid-type ion-crosslinked polymer is used instead of a zirconium-phosphorus composite oxide carrier. Specifically, in S1, a commercially available polymer with a specific surface area of ​​17 m² is used. 2 / g~22m 2 / g, average pore size 25 nm~30 nm, pore volume 0.002 cm³ 3 / g~0.003cm 3 / g of sulfonic acid type ion crosslinked polymer.

[0147] Comparative Example 3

[0148] The preparation method of Comparative Example 3 is basically the same as that of Example 1, except that: an alumina-zirconium-phosphorus composite oxide carrier is used. Specifically, in S1, a commercially available carrier with a specific surface area of ​​200 m² is used. 2 / g~250 m 2 / g of alumina with an average particle size of 0.1~1.0μm.

[0149] The performance of the palladium-supported catalysts prepared in each embodiment and comparative example was tested, including:

[0150] (1) Carbon dioxide temperature-programmed desorption was used to characterize the alkalinity of the catalyst surface. 0.1 g of palladium-supported zirconium-based composite oxide catalyst sample was weighed and placed in a quartz reactor. After heating from room temperature to 400 °C, the reactor was purged for 1 h (high-purity Ar atmosphere), and then cooled to 120 °C under the same atmosphere. The carbon dioxide gas valve was switched, and adsorption was saturated. Then, the reactor was purged with pure argon (30 mL / min) until baseline equilibrium was reached. Finally, temperature-programmed desorption was performed from room temperature to 800 °C (heating rate: 10 °C / min). The carbon dioxide signal in the tail gas was collected using a thermal conductivity detector.

[0151] (2) Ammonia temperature-programmed desorption was used to characterize the acidity of the catalyst surface. 0.1 g of palladium-supported zirconium-based composite oxide catalyst sample was weighed and placed in a quartz reactor. The temperature was raised from room temperature to 400 °C and then purged for 1 h (high-purity He atmosphere), followed by cooling to 50 °C under the same atmosphere. The ammonia gas valve was switched, and adsorption was saturated. Then, the reactor was purged with pure helium (30 mL / min) until baseline equilibrium was reached. Finally, temperature-programmed desorption was performed from room temperature to 600 °C (heating rate: 10 °C / min). The ammonia signal in the tail gas was collected using a thermal conductivity detector.

[0152] (3) Carbon monoxide pulse adsorption to characterize palladium dispersion: 0.1 g of palladium-supported zirconium-based composite oxide catalyst sample was weighed and placed in a quartz reactor. The temperature was programmed to 200 °C under Ar atmosphere (heating rate 15 °C / min) and purged at this temperature for 1 h. Then, the temperature was allowed to naturally decrease to room temperature under Ar atmosphere. A CO / Ar (10 / 90, volume ratio) mixture was switched for pulse adsorption, and the CO signal was detected using a thermal conductivity detector. Dispersion ( The calculation method for ) is as follows: , denoted as ρ, where m is the amount of CO adsorbed, m is the mass of the catalyst sample, and a is the mass fraction of Pd in ​​the catalyst. denoted as Pd, where Pd is the relative atomic mass.

[0153] (4) N2 physical adsorption / desorption, characterizing the specific surface area of ​​the catalyst, 0.5 g of palladium-supported zirconium-based composite oxide catalyst sample was weighed and degassed at 180 °C for 6 h, followed by N2 adsorption / desorption experiments at 77 K. The specific surface area of ​​the catalyst sample was calculated using the Brunauer-Emmet-Teller method.

[0154] The palladium-supported zirconium-based composite oxide catalysts prepared in the various examples and comparative examples were used to synthesize diisobutyl ketone in a one-step process with acetone. The performance of the catalytic synthesis and other characterization results are shown in Table 1.

[0155] Table 1

[0156] Acetone conversion rate (%) Diisobutyl ketone selectivity (%) Methyl isobutyl ketone selectivity (%) Palladium loading (wt%) Palladium dispersion (%) Example 1 93 60 24 0.54 63.27 Example 2 91 61 25 0.52 73.29 Example 3 90 59 20 0.51 55.72 Example 4 92 58 20 0.50 56.89 Example 5 95 66 21 0.53 85.32 Example 6 40 50 23 0.50 3.2 Comparative Example 1 34 10 40 0.52 50.25 Comparative Example 2 85 5 82 0.52 2.7

[0157] As can be seen from Examples 1 to 5 and Table 1, different elements and zirconium oxide can form composite oxide supports that can improve the properties of the original zirconium oxide support in a variety of ways, thereby increasing the conversion rate of acetone and the selectivity of diisobutyl ketone.

[0158] The introduction of phosphorus can regulate the electron density of palladium. High-valence phosphorus, as an electron acceptor, can effectively stabilize electron-deficient palladium atoms, enhance the interaction between palladium and the composite oxide support, and inhibit the migration and aggregation of the noble metal palladium. At the same time, phosphorus can increase the concentration of Brønsted acid sites on the composite oxide support. Brønsted acid sites continuously release hydrogen during the catalytic synthesis of diisobutyl ketone, promoting the hydrogenation and dehydration condensation of acetone to form diisobutyl ketone.

[0159] Since the radius of cerium atoms is significantly larger than that of zirconium atoms, the introduction of cerium can increase oxygen vacancies in the composite oxide and exacerbate lattice distortion. In addition, the noble metal palladium forms Pd-O-Ce bonds with cerium in the composite oxide, which increases the anchoring effect between palladium atoms and the composite oxide support, and slows down the migration and aggregation of noble metal palladium caused by its large surface energy. At the same time, the high concentration of oxygen vacancies can affect the electronic state density of palladium and improve the selectivity of diisobutyl ketone.

[0160] Magnesium has a similar ionic radius to zirconium, but the valence state of magnesium ions is lower than that of zirconium. When magnesium does not form a complex oxide with zirconium, the complex oxide support will form more oxygen vacancies, which can effectively fix palladium. At the same time, it affects the electronic state density of palladium and improves the selectivity of diisobutyl ketone.

[0161] Silicon has a higher electronegativity than zirconium. Therefore, the introduction of silicon can reduce the electron cloud density of oxygen bonded to silicon, thereby forming more Brønsted acid sites. During the catalytic synthesis of diisobutyl ketone, hydrogen is continuously released, promoting the hydrogenation of the reaction intermediate to form diisobutyl ketone. At the same time, the unsaturated coordinated silicon and zirconium in the zirconium-silicon composite oxide support are themselves Lewis acid sites. Lewis acid sites can promote the condensation reaction of acetone to form C-C bonds.

[0162] UiO-66 possesses a high specific surface area and mesoporous / microporous structure, providing a spatial structure for the high loading and high dispersibility of the noble metal palladium. At the same time, the regular and appropriately sized pore structure allows reactants and products to diffuse relatively quickly and smoothly, reducing the residence time of reaction intermediates or products in the pores. This, to a certain extent, avoids excessive side reactions and carbon deposition caused by excessive retention of reaction intermediates or products, thereby improving the catalytic efficiency of the catalyst.

[0163] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0164] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A supported zirconium-based catalyst, characterized in that, Includes a zirconium-based support and a noble metal supported on the zirconium-based support; The zirconium-based support includes one or more of zirconium-based composite oxide supports and zirconium-based metal-organic framework materials. The zirconium-based composite oxide support includes a composite of zirconium oxide and other oxides, wherein the other oxides include oxides of one or more elements selected from Si, P, Ce and Mg.

2. The supported zirconium-based catalyst as described in claim 1, characterized in that, The zirconium-based composite oxide support satisfies one or more of the following conditions: (1) The chemical formula of the zirconium-based composite oxide support is ZrM x O y M includes one or more of Si, P, Ce and Mg, where 0 < x ≤ 10 and 2 ≤ y ≤ 50; (2) The average particle size of the zirconium-based composite oxide support is 0.1 μm to 1.0 μm.

3. The supported zirconium-based catalyst as described in claim 1, characterized in that, The zirconium-based metal-organic framework material includes a zirconium metal cluster and an organic ligand coordinated with the zirconium metal cluster; The zirconium metal clusters include one or more of Zr6O8, Zr8O6, ZrO6, ZrO7, and ZrO8; The organic ligands include one or more of the following: terephthalic acid and its derivatives, biphenyl dicarboxylic acid and its derivatives, naphthalene dicarboxylic acid and its derivatives, 1,3,5-tris(carboxyphenyl)benzene and its derivatives, 1,2,4,5-tetra(4-carboxyphenyl)benzene and its derivatives, methyl-tetra(4-carboxyphenyl)porphyrin and its derivatives, pyrazole-3,5-dicarboxylic acid and its derivatives, and 1,3,5-benzenetricarboxylic acid and its derivatives.

4. The supported zirconium-based catalyst as described in claim 1, characterized in that, The zirconium-based metal-organic framework material satisfies one or more of the following conditions: (1) The specific surface area of ​​the zirconium-based metal-organic framework material is 600 m². 2 / g~800m 2 / g; (2) The average pore size of the zirconium-based metal-organic framework material is 1 nm to 5 nm; (2) The pore volume of the zirconium-based metal-organic framework material is 0.5 cm³. 3 / g~1cm 3 / g.

5. The supported zirconium-based catalyst according to any one of claims 1 to 4, characterized in that, The precious metal has a mass content of 0.1wt% to 1.0wt% relative to the zirconium-based support.

6. The method for preparing the supported zirconium-based catalyst according to any one of claims 1 to 5, characterized in that, Includes the following steps: A mixed suspension is obtained by mixing a noble metal salt, a zirconium-based support, and a solvent. The mixed suspension was separated into solid and liquid components to obtain a solid catalyst precursor; The solid catalyst precursor was calcined to obtain the supported zirconium-based catalyst.

7. The preparation method according to claim 6, characterized in that, A complexing agent is also added to the mixed suspension, which includes one or more of citric acid, β-cyclodextrin, ethylenediamine, hexadecyltrimethylammonium chloride, and ethylenediaminetetraacetic acid.

8. The preparation method according to claim 7, characterized in that, One or more of the following conditions must be met: (1) The mass ratio of the complexing agent to the noble metal salt is 23:1 to 3:1; (2) The mass content of the noble metal salt relative to the zirconium-based support is 0.17wt%~1.7wt%.

9. A method for preparing diisobutyl ketone, characterized in that, Includes the following steps: Using the supported zirconium-based catalyst as described in any one of claims 1 to 5 or the supported zirconium-based catalyst prepared by the preparation method as described in any one of claims 6 to 8, acetone is used as a raw material to catalyze the synthesis of diisobutyl ketone.

10. The method for preparing diisobutyl ketone according to claim 9, characterized in that, The reaction temperature for synthesizing the diisobutyl ketone is 140℃~160℃, the reaction pressure is 0.9~1.1 standard atmospheres, and the feed space velocity of the acetone is 1.00 h⁻¹. -1 ~3.00h -1 The molar ratio of hydrogen to acetone is 0.3 to 0.5.

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