Phenol selective hydrogenation catalyst, its preparation method and application

Abstract

A selective hydrogenation catalyst for phenol comprises a support and an active component loaded on the surface of the support; wherein the support is a base-modified molecular sieve; the active component comprises a primary active component and a secondary active component; the primary active component comprises palladium; and the secondary active component comprises boron and / or niobium. Using a base-modified molecular sieve as a support and loading the primary and secondary active components, the active component is fully dispersed on the support, exhibiting excellent catalytic activity for the hydrogenation of phenol to cyclohexanone. The catalytic performance is stable and has high practical value.

Description

Technical Field

[0001] This invention relates to a hydrogenation catalyst, its preparation method, and its application, specifically to a selective hydrogenation catalyst for phenol, its preparation method, and its application, belonging to the field of chemical engineering. Background Technology

[0002] Cyclohexanone is a colorless, transparent liquid used industrially as a raw material and solvent in organic synthesis. Currently, cyclohexanone is mainly used to synthesize caprolactam and adipic acid, and is an important basic chemical raw material for the production of nylon 6 and nylon 66. It can also be used in the production of herbicides, antihistamines, and polyesters. Therefore, the green synthesis of cyclohexanone has attracted widespread attention.

[0003] Currently, cyclohexanone production processes include cyclohexane oxidation, cyclohexene hydration, and phenol hydrogenation. Among these, cyclohexane oxidation has a long operating cycle, low cyclohexanone yield, and complex separation processes, making it unsuitable for large-scale industrial production. Cyclohexene hydration has a simple process route, but the reaction conditions are harsh, typically occurring at high temperatures, and existing catalysts are prone to deactivation. Phenol hydrogenation offers advantages such as simple operation, high reaction efficiency, and high cyclohexanone yield; moreover, phenol is widely available from biomass pyrolysis and coal chemical processes. Furthermore, catalytic hydrogenation to produce widely applicable cyclohexanone reduces the consumption of petroleum resources. Therefore, phenol hydrogenation is a more valuable industrial application and environmentally significant route for cyclohexanone synthesis.

[0004] Currently, the catalysts for the hydrogenation of phenol to cyclohexanone are mainly palladium-based catalysts. Studies have found that the catalytic activity of the phenol hydrogenation process is related to the particle size, morphology, crystallinity, and surface state of the noble metal nanoparticles. Notably, when the noble metal nanoparticles have very small particle sizes and large specific surface areas, they can achieve catalytic effects that are difficult to achieve with larger particles. However, small-sized noble metal nanoparticles are prone to aggregation or leaching during the reaction, leading to reduced catalytic activity for phenol hydrogenation and resulting in resource waste.

[0005] In summary, in existing catalytic hydrogenation processes for the production of cyclohexanone from phenol, the active metal particles supported on the catalyst tend to agglomerate or leach when their size is small, while the catalytic effect is poor when the active metal particles are large. Furthermore, the unstable performance of the catalyst can easily lead to a decrease in the yield of cyclohexanone or the formation of other isomers, resulting in unsatisfactory product selectivity. Summary of the Invention

[0006] To address the problems of low cyclohexanone yield, harsh reaction conditions, and unstable catalyst performance in phenol catalytic hydrogenation of existing technologies, which easily lead to reduced cyclohexanone yield and unsatisfactory product selectivity, this invention proposes a phenol selective hydrogenation catalyst. This catalyst utilizes modified molecular sieves as a support and loads multiple active components onto the support, improving catalyst stability and product selectivity. Under relatively mild reaction conditions, it enhances the yield and purity of cyclohexanone, demonstrating high practical value.

[0007] According to a first embodiment of the present invention, a phenol selective hydrogenation catalyst is provided.

[0008] A selective hydrogenation catalyst for phenol includes a support and an active component supported on the surface of the support; wherein the support is a molecular sieve modified with base groups; the active component includes a main active component and a secondary active component; the main active component includes palladium; and the secondary active component includes boron and / or niobium.

[0009] Preferably, the base-modified molecular sieve is an H-ZSM-5 molecular sieve modified with an amino-containing modifier or an MCM-41 molecular sieve modified with an amino-containing modifier; preferably, the amino-containing modifier is tris(dimethylamino)silane (CAS: 15112-89-7), butyldimethyl(dimethylamino)silane (CAS: 181231-67-4), tetra(dimethylamino)silane (CAS: 1624-01-7), bis(tert-butyl)silane, etc. The silane is selected from one or more of the following: (3-aminopropyl)silane (CAS: 186598-40-3), trimethoxy[3-(phenylamino)propyl]silane (CAS: 3068-76-6), 3-aminopropyltrimethoxysilane (CAS: 13822-56-5), and (3-aminopropyl)dimethylmethoxysilane (CAS: 31024-26-7), with 3-aminopropyltrimethoxysilane or (3-aminopropyl)dimethylmethoxysilane being more preferably selected from the following: (3-aminopropyl)dimethylmethoxysilane (CAS: 186598-40-3), trimethoxy[3-(phenylamino)propyl]silane (CAS: 3068-76-6), 3-aminopropyltrimethoxysilane (CAS: 13822-56-5), and (3-aminopropyl)dimethylmethoxysilane (CAS: 31024-26-7).

[0010] Preferably, the content of the base groups in the catalyst is 0.05% to 1% of the carrier mass, and more preferably 0.3% to 0.9%.

[0011] Preferably, the content of the main active component in the catalyst is 0.5% to 2% of the support mass, and more preferably 1% to 1.6%.

[0012] Preferably, the content of the secondary active component in the catalyst is 0.1% to 0.5% of the support mass, and more preferably 0.2% to 0.4%.

[0013] Preferably, the secondary active components include boron and niobium, wherein the mass ratio of boron to niobium is 1:1 to 1.7, preferably 1:1.2 to 1.4.

[0014] According to a second embodiment of the present invention, a method for preparing a phenol selective hydrogenation catalyst is provided.

[0015] A method for preparing a phenol selective hydrogenation catalyst, the method comprising the following steps:

[0016] 1) Add molecular sieve and modifier to solvent I, heat and reflux, filter, and dry the resulting solid to obtain modified molecular sieve support;

[0017] 2) First, add the main active component precursor, the secondary active component precursor and sodium chloride to solvent II, then add the modified molecular sieve support obtained in step 1), and after sonication, impregnation and drying, grind the solid into powder to obtain powdered solid.

[0018] 3) The powdered solid obtained in step 2) is calcined in a reducing gas atmosphere to obtain a phenol selective hydrogenation catalyst.

[0019] Preferably, the molecular sieve in step 1) is H-ZSM-5 molecular sieve or MCM-41 molecular sieve.

[0020] Preferably, the modifier in step 1) is one of tris(dimethylamino)silane, butyldimethyl(dimethylamino)silane, tetra(dimethylamino)silane, bis(tert-butylamino)silane, trimethoxy[3-(phenylamino)propyl]silane, 3-aminopropyltrimethoxysilane, and (3-aminopropyl)dimethylmethoxysilane, preferably 3-aminopropyltrimethoxysilane or (3-aminopropyl)dimethylmethoxysilane.

[0021] Preferably, solvent I in step 1) is one or more of toluene, xylene, and dichloromethane.

[0022] Preferably, the heating in step 1) is to raise the solution to 90-130°C, more preferably 100-120°C.

[0023] Preferably, the reflux time in step 1) is 10-15 hours, more preferably 11-13 hours.

[0024] Preferably, the drying temperature in step 1) is 60–100°C, and more preferably 70–90°C.

[0025] Preferably, the solid-liquid ratio of the molecular sieve and the modifier in step 1) is 0.3–3 g / mL, and more preferably 1.5–2.5 g / mL.

[0026] Preferably, the precursor of the main active component in step 2) is one of palladium nitrate, palladium chloride, or palladium acetate, with palladium nitrate being the most preferred.

[0027] Preferably, the precursor of the secondary active component in step 2) is boric acid and / or niobium oxalate, preferably a mixture of boric acid and niobium oxalate in a mass ratio of 0.7 to 1.5:1; more preferably, the mass ratio of boric acid to niobium oxalate is 0.8 to 1.1:1.

[0028] Preferably, solvent II in step 2) is deionized water.

[0029] Preferably, the ultrasound time in step 2) is 20 to 50 minutes, more preferably 25 to 40 minutes.

[0030] Preferably, the soaking time in step 2) is 8 to 18 hours, more preferably 10 to 14 hours.

[0031] Preferably, the drying temperature in step 2) is 50–100°C, and more preferably 70–90°C.

[0032] Preferably, the drying time in step 2) is 16 to 30 hours, more preferably 20 to 28 hours.

[0033] Preferably, the amount of the main active component precursor added in step 2) is 1%-20% of the mass of the modified molecular sieve support, and more preferably 8%-15%.

[0034] Preferably, the amount of the precursor of the secondary active component added in step 2) is 0.3%-3.5% of the mass of the modified molecular sieve support, and more preferably 0.8%-3%.

[0035] Preferably, the roasting temperature in step 3) is 300–500°C, and more preferably 350–450°C.

[0036] Preferably, the roasting time in step 3) is 2 to 10 hours, more preferably 4 to 7 hours.

[0037] Preferably, the reducing gas in step 3) is hydrogen.

[0038] Preferably, step 1) specifically involves: adding the molecular sieve and modifier to toluene, heating to 90–130°C (preferably 100–120°C), and refluxing at this temperature for 10–15 h (preferably 11–13 h), filtering to obtain a solid, and drying the solid at 60–100°C (preferably 70–90°C) to obtain the modified molecular sieve support.

[0039] Preferably, step 2) specifically involves: adding palladium precursor, boron precursor, niobium precursor, and sodium chloride to deionized water, and adding the modified molecular sieve support obtained in step 1); wherein the amount of palladium precursor added is 1%-20% (preferably 8%-15%), the amount of boron precursor added is 0.1%-1.5% (preferably 0.6%-1.2%), and the amount of niobium precursor added is 0.2%-2.0% (preferably 0.5%-1.5%); then sonicating the solution for 20-50 min (preferably 25-40 min), soaking for 8-18 h (preferably 10-14 h) after sonication, drying the resulting solution at 50-100℃ (preferably 70-90℃) for 16-30 h (preferably 20-28 h), and grinding the resulting solid into powder to obtain a powdered solid.

[0040] Preferably, step 3) specifically involves calcining the powdered solid obtained in step 2) at 300–500°C (preferably 350–450°C) for 2–10 h (preferably 4–7 h) while simultaneously introducing hydrogen gas to obtain a phenol selective hydrogenation catalyst.

[0041] According to a third embodiment of the present invention, a method for preparing cyclohexanone is provided.

[0042] A method for preparing cyclohexanone, the method comprising the following steps:

[0043] A) Add solvent III, phenol and phenol selective hydrogenation catalyst to the reaction vessel, replace the air in the reaction vessel with hydrogen, heat and stir the reaction, cool down after the reaction is completed, filter the reaction liquid in the vessel to obtain cyclohexanone.

[0044] Preferably, solvent III in step A) is dichloromethane.

[0045] Preferably, the mass ratio of phenol to solvent III in step A) is 0.01 to 0.05:1, more preferably 0.02 to 0.04:1.

[0046] Preferably, the molar ratio of the phenol selective hydrogenation catalyst to phenol in step A) is 0.01 to 0.1:1, more preferably 0.03 to 0.07:1.

[0047] Preferably, the pressure of the hydrogen gas in step A) is 0.2 to 2 MPa, more preferably 0.8 to 1.4 MPa.

[0048] Preferably, the heating temperature in step A) is 40–110°C, and more preferably 60–90°C.

[0049] Preferably, the stirring speed of the stirring reaction in step A) is 100 to 1000 rpm, and more preferably 300 to 700 rpm.

[0050] Preferably, the stirring reaction time in step A) is 1 to 8 hours, more preferably 3 to 6 hours.

[0051] Preferably, step A) specifically involves: adding dichloromethane, phenol, and a phenol selective hydrogenation catalyst to the reactor; sealing the reactor and evacuating it to a vacuum; introducing nitrogen gas at 0.7–1.3 MPa; evacuating the reactor to a vacuum state again; repeating the nitrogen gas purging step 2–5 times; replacing the air in the reactor with hydrogen gas; evacuating the reactor to a vacuum state again; introducing hydrogen gas to adjust the pressure to 0.2–2 MPa (preferably 0.8–1.4 MPa); heating the solution in the reactor to 40–110°C (preferably 60–90°C); stirring the reaction at 100–1000 rpm (preferably 300–700 rpm) for 1–8 h (preferably 3–6 h); cooling after the reaction is complete; and filtering the solution in the reactor to obtain cyclohexanone.

[0052] In this invention, molecular sieves are used as the support, and basic groups are introduced for modification. The basic group-modified molecular sieves can promote the interaction between the active components on the support and the support surface, uniformly stabilize the ultrafine active component particles, promote the dispersion of the active components, and provide basic centers on the support surface to promote the vertical adsorption of phenol molecules. Thus, it exhibits excellent catalytic activity for the hydrogenation of phenol to cyclohexanone, reduces the loss of active components during the reaction, and improves the stability of the catalyst.

[0053] In this invention, the main active component and the secondary active component are simultaneously loaded on the support. The interaction between the main active component and the secondary active component is used to improve the catalytic efficiency between the active component and the reactants. Moreover, compared with a single palladium active component, the combination of palladium with boron and niobium used in this invention can significantly improve the selectivity of phenol to cyclohexanone conversion and obtain cyclohexanone product with higher purity.

[0054] In this invention, the amount of base groups added is limited. In the catalyst, the mass of the base groups is 0.05% to 1% of the mass of the support (e.g., 0.050%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.5%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, 1%). The specifications also define the mass of the main active component and the secondary active component, as well as the mass ratio of boron to niobium in the secondary active component. The mass of the main active component is 0.5% to 2% of the carrier mass (e.g., 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%), the mass of the secondary active component is 0.1% to 0.5% of the carrier mass (e.g., 0.1%, 0.2%, 0.3%, 0.4%, 0.5%), and the mass ratio of boron to niobium in the secondary active component is 1:1 to 1.7 (e.g., 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7).

[0055] In this invention, since the basic coupling agent and the precursors of palladium, boron, and niobium cannot be fully loaded onto the molecular sieve during catalyst preparation, the amount of each substance and the process conditions adopted in the catalyst preparation process are limited based on the losses during the loading process. Specifically, the solid-liquid ratio of the molecular sieve to the basic coupling agent is 0.3–3 g / mL, the amount of palladium precursor added is 1%–20%, the amount of boron precursor added is 0.1%–1.5%, and the amount of niobium precursor added is 0.2%–2.0%. Based on the above dosage ratios, after the loss of some active components during the preparation process, the modified substances and active components on the obtained catalyst are within the optimal mass range, and the catalyst exhibits good catalytic performance and stability.

[0056] In this invention, palladium exists in the catalyst in a mixed form of elemental and oxidized states. Boron, after being calcined at high temperature, mostly reacts with the metal to form M... x B x This compound exists, while niobium exists in its oxidized state. Furthermore, the mass percentages of palladium, boron, and niobium described in this invention are all calculated by mass of the elements. Compared with the prior art, this invention has the following beneficial effects:

[0057] 1. The present invention provides a selective hydrogenation catalyst for phenol, which uses a molecular sieve modified with a base group as a support and loads a main active component and a secondary active component. The active component is fully dispersed on the support and has excellent catalytic activity for the hydrogenation of phenol to cyclohexanone. The catalytic performance is stable and has high practical value.

[0058] 2. The present invention provides a method for preparing a selective hydrogenation catalyst for phenol. Based on the loading loss during the loading process, the amount of each compound added during the preparation process is strictly limited, and a catalyst with the active component loading rate in the optimal range is obtained, which has good catalytic performance and a simple preparation process.

[0059] 3. The present invention provides a method for preparing cyclohexanone by adding a phenol selective hydrogenation catalyst to reduce the generation of byproducts, and the obtained cyclohexanone has high purity. Attached Figure Description

[0060] Figure 1 This is a TEM image of a phenol selective hydrogenation catalyst provided in Example 1.

[0061] Figure 2 The image shows the XRD pattern of a phenol selective hydrogenation catalyst provided in Example 1.

[0062] Figure 3 The X-ray photoelectron spectrum of a phenol selective hydrogenation catalyst provided in Example 1. Detailed Implementation

[0063] The technical solution of the present invention will be illustrated below with examples. The scope of protection sought by the present invention includes, but is not limited to, the following embodiments.

[0064] According to a first embodiment of the present invention, a phenol selective hydrogenation catalyst is provided.

[0065] A selective hydrogenation catalyst for phenol includes a support and an active component supported on the surface of the support; wherein the support is a molecular sieve modified with base groups; the active component includes a main active component and a secondary active component; the main active component includes palladium; and the secondary active component includes boron and / or niobium.

[0066] Preferably, the base-modified molecular sieve is an H-ZSM-5 molecular sieve modified with an amino-containing modifier or an MCM-41 molecular sieve modified with an amino-containing modifier; preferably, the amino-containing modifier is one or more of tris(dimethylamino)silane, butyldimethyl(dimethylamino)silane, tetra(dimethylamino)silane, bis(tert-butylamino)silane, trimethoxy[3-(phenylamino)propyl]silane, 3-aminopropyltrimethoxysilane, and (3-aminopropyl)dimethylmethoxysilane, more preferably 3-aminopropyltrimethoxysilane or (3-aminopropyl)dimethylmethoxysilane.

[0067] Preferably, the content of the base groups in the catalyst is 0.05% to 1% of the carrier mass, and more preferably 0.3% to 0.9%.

[0068] Preferably, the content of the main active component in the catalyst is 0.5% to 2% of the support mass, and more preferably 1% to 1.6%.

[0069] Preferably, the content of the secondary active component in the catalyst is 0.1% to 0.5% of the support mass, and more preferably 0.2% to 0.4%.

[0070] Preferably, the secondary active components include boron and niobium, wherein the mass ratio of boron to niobium is 1:1 to 1.7, preferably 1:1.2 to 1.4.

[0071] According to a second embodiment of the present invention, a method for preparing a phenol selective hydrogenation catalyst is provided.

[0072] A method for preparing a phenol selective hydrogenation catalyst, the method comprising the following steps:

[0073] 1) Add molecular sieve and modifier to solvent I, heat and reflux, filter, and dry the resulting solid to obtain modified molecular sieve support;

[0074] 2) First, add the main active component precursor, the secondary active component precursor and sodium chloride to solvent II, then add the modified molecular sieve support obtained in step 1), and after sonication, impregnation and drying, grind the solid into powder to obtain powdered solid.

[0075] 3) The powdered solid obtained in step 2) is calcined in a reducing gas atmosphere to obtain a phenol selective hydrogenation catalyst.

[0076] Preferably, the molecular sieve in step 1) is H-ZSM-5 molecular sieve or MCM-41 molecular sieve.

[0077] Preferably, the modifier in step 1) is one of tris(dimethylamino)silane, butyldimethyl(dimethylamino)silane, tetra(dimethylamino)silane, bis(tert-butylamino)silane, trimethoxy[3-(phenylamino)propyl]silane, 3-aminopropyltrimethoxysilane, and (3-aminopropyl)dimethylmethoxysilane, preferably 3-aminopropyltrimethoxysilane or (3-aminopropyl)dimethylmethoxysilane.

[0078] Preferably, solvent I in step 1) is one or more of toluene, xylene, and dichloromethane.

[0079] Preferably, the heating in step 1) is to raise the solution to 90-130°C, more preferably 100-120°C.

[0080] Preferably, the reflux time in step 1) is 10-15 hours, more preferably 11-13 hours.

[0081] Preferably, the drying temperature in step 1) is 60–100°C, and more preferably 70–90°C.

[0082] Preferably, the solid-liquid ratio of the molecular sieve and the modifier in step 1) is 0.3–3 g / mL, and more preferably 1.5–2.5 g / mL.

[0083] Preferably, the precursor of the main active component in step 2) is one of palladium nitrate, palladium chloride, or palladium acetate, with palladium nitrate being the most preferred.

[0084] Preferably, the precursor of the secondary active component in step 2) is boric acid and / or niobium oxalate, preferably a mixture of boric acid and niobium oxalate in a mass ratio of 0.7 to 1.5:1; more preferably, the mass ratio of boric acid to niobium oxalate is 0.8 to 1.1:1.

[0085] Preferably, solvent II in step 2) is deionized water.

[0086] Preferably, the ultrasound time in step 2) is 20 to 50 minutes, more preferably 25 to 40 minutes.

[0087] Preferably, the soaking time in step 2) is 8 to 18 hours, more preferably 10 to 14 hours.

[0088] Preferably, the drying temperature in step 2) is 50–100°C, and more preferably 70–90°C.

[0089] Preferably, the drying time in step 2) is 16 to 30 hours, more preferably 20 to 28 hours.

[0090] Preferably, the amount of the main active component precursor added in step 2) is 1%-20% of the mass of the modified molecular sieve support, and more preferably 8%-15%.

[0091] Preferably, the amount of the precursor of the secondary active component added in step 2) is 0.3%-3.5% of the mass of the modified molecular sieve support, and more preferably 0.8%-3%.

[0092] Preferably, the roasting temperature in step 3) is 300–500°C, and more preferably 350–450°C.

[0093] Preferably, the roasting time in step 3) is 2 to 10 hours, more preferably 4 to 7 hours.

[0094] Preferably, the reducing gas in step 3) is hydrogen.

[0095] Preferably, step 1) specifically involves: adding the molecular sieve and modifier to toluene, heating to 90–130°C (preferably 100–120°C), and refluxing at this temperature for 10–15 h (preferably 11–13 h), filtering to obtain a solid, and drying the solid at 60–100°C (preferably 70–90°C) to obtain the modified molecular sieve support.

[0096] Preferably, step 2) specifically involves: adding palladium precursor, boron precursor, niobium precursor, and sodium chloride to deionized water, and adding the modified molecular sieve support obtained in step 1); wherein the amount of palladium precursor added is 1%-20% (preferably 8%-15%), the amount of boron precursor added is 0.1%-1.5% (preferably 0.6%-1.2%), and the amount of niobium precursor added is 0.2%-2.0% (preferably 0.5%-1.5%); then sonicating the solution for 20-50 min (preferably 25-40 min), soaking for 8-18 h (preferably 10-14 h) after sonication, drying the resulting solution at 50-100℃ (preferably 70-90℃) for 16-30 h (preferably 20-28 h), and grinding the resulting solid into powder to obtain a powdered solid.

[0097] Preferably, step 3) specifically involves calcining the powdered solid obtained in step 2) at 300–500°C (preferably 350–450°C) for 2–10 h (preferably 4–7 h) while simultaneously introducing hydrogen gas to obtain a phenol selective hydrogenation catalyst.

[0098] According to a third embodiment of the present invention, a method for preparing cyclohexanone is provided.

[0099] A method for preparing cyclohexanone, the method comprising the following steps:

[0100] A) Add solvent III, phenol and phenol selective hydrogenation catalyst to the reaction vessel, replace the air in the reaction vessel with hydrogen, heat and stir the reaction, cool down after the reaction is completed, filter the reaction liquid in the vessel to obtain cyclohexanone.

[0101] Preferably, solvent III in step A) is dichloromethane.

[0102] Preferably, the mass ratio of phenol to solvent III in step A) is 0.01 to 0.05:1, more preferably 0.02 to 0.04:1.

[0103] Preferably, the molar ratio of the phenol selective hydrogenation catalyst to phenol in step A) is 0.01 to 0.1:1, more preferably 0.03 to 0.07:1.

[0104] Preferably, the pressure of the hydrogen gas in step A) is 0.2 to 2 MPa, more preferably 0.8 to 1.4 MPa.

[0105] Preferably, the heating temperature in step A) is 40–110°C, and more preferably 60–90°C.

[0106] Preferably, the stirring speed of the stirring reaction in step A) is 100 to 1000 rpm, and more preferably 300 to 700 rpm.

[0107] Preferably, the stirring reaction time in step A) is 1 to 8 hours, more preferably 3 to 6 hours.

[0108] Preferably, step A) specifically involves: adding dichloromethane, phenol, and a phenol selective hydrogenation catalyst to the reactor; sealing the reactor and evacuating it to a vacuum; introducing nitrogen gas at 0.7–1.3 MPa; evacuating the reactor to a vacuum state again; repeating the nitrogen gas purging step 2–5 times; replacing the air in the reactor with hydrogen gas; evacuating the reactor to a vacuum state again; introducing hydrogen gas to adjust the pressure to 0.2–2 MPa (preferably 0.8–1.4 MPa); heating the solution in the reactor to 40–110°C (preferably 60–90°C); stirring the reaction at 100–1000 rpm (preferably 300–700 rpm) for 1–8 h (preferably 3–6 h); cooling after the reaction is complete; and filtering the solution in the reactor to obtain cyclohexanone.

[0109] Preparation Example 1

[0110] 1) Mix 20g of H-ZSM-5 molecular sieve and 40mL of (3-aminopropyl)dimethylmethoxysilane, add to 1000mL of toluene solution, heat to 110℃ and reflux at this temperature for 12h, filter to obtain solid, dry the solid at 80℃, and after drying, obtain 19.1g of modified molecular sieve support.

[0111] 2) Add 1g palladium nitrate, 0.09g boric acid, 0.1g niobium oxalate and 1g sodium chloride to 1000mL deionized water, and add 10g of the modified molecular sieve support obtained in step 1). Sonicate the solution for 30min, and after sonication, soak for 12h. Dry the obtained solution at 80℃ for 24h. Grind the obtained solid into powder to obtain 8.6g of powdered solid.

[0112] 3) The 8.6g powdered solid obtained in step 3) was calcined at 400℃ for 5h while hydrogen was introduced. After calcination, 7.2g of phenol selective hydrogenation catalyst was obtained.

[0113] The phenol selective hydrogenation catalyst obtained in step 3) is tested, wherein the mass of the base group is 0.61% of the support mass, the mass of the main active component palladium is 1.31% of the support mass, the mass of the secondary active component is 0.29% of the support mass, and the mass ratio of boron to niobium in the secondary active component is 1:1.31.

[0114] Preparation Example 2

[0115] 1) Mix 18g of H-ZSM-5 molecular sieve and 39mL of (3-aminopropyl)dimethylmethoxysilane, add to 1000mL of toluene solution, heat to 110℃ and reflux at this temperature for 12h, filter to obtain solid, dry the solid at 80℃, and after drying, obtain 16.8g of modified molecular sieve support.

[0116] 2) Add 1.1g palladium nitrate, 0.1g boric acid, 0.08g niobium oxalate and 1g sodium chloride to 1000mL deionized water, and add 10g of the modified molecular sieve support obtained in step 1). Sonicate the solution for 30min, and after sonication, soak for 12h. Dry the obtained solution at 80℃ for 24h. Grind the obtained solid into powder to obtain 8.4g of powdered solid.

[0117] 3) The 8.4g powdered solid obtained in step 3) was calcined at 400℃ for 5h while hydrogen was introduced. After calcination, 6.9g of phenol selective hydrogenation catalyst was obtained.

[0118] The selective hydrogenation catalyst for phenol obtained in step 3) is tested, wherein the mass of the base group is 0.58% of the support mass, the mass of the main active component palladium is 1.29% of the support mass, the mass of the secondary active component is 0.31% of the support mass, and the mass ratio of boron to niobium in the secondary active component is 1:1.30.

[0119] Preparation Example 3

[0120] 1) Mix 21g of H-ZSM-5 molecular sieve and 40mL of (3-aminopropyl)dimethylmethoxysilane, add to 1000mL of toluene solution, heat to 110℃ and reflux at this temperature for 12h, filter to obtain solid, dry the solid at 80℃, and after drying, obtain 19.7g of modified molecular sieve support.

[0121] 2) Add 1.2g palladium nitrate, 0.11g boric acid, 0.12g niobium oxalate and 1g sodium chloride to 1000mL deionized water, and add 10g of the modified molecular sieve support obtained in step 1). Sonicate the solution for 30min, and after sonication, soak for 12h. Dry the resulting solution at 80℃ for 24h. Grind the resulting solid into powder to obtain 9.1g of powdered solid.

[0122] 3) The 9.1g powdered solid obtained in step 3) was calcined at 400℃ for 5h while hydrogen was introduced. After calcination, 8.2g of phenol selective hydrogenation catalyst was obtained.

[0123] The selective hydrogenation catalyst for phenol obtained in step 3) is tested, wherein the mass of the base group is 0.60% of the support mass, the mass of the main active component palladium is 1.32% of the support mass, the mass of the secondary active component is 0.27% of the support mass, and the mass ratio of boron to niobium in the secondary active component is 1:1.29.

[0124] Using the same method as in Example 1, parallel experiments were conducted by adjusting the amounts of H-ZSM-5 molecular sieve and (3-aminopropyl)dimethylmethoxysilane added in step 1) or the amounts of palladium nitrate, boric acid, and niobium oxalate added in step 2) to obtain catalysts with different base group masses, different loading amounts of the main active component palladium, different loading amounts of the secondary active components boron and niobium, and different ratios of boron and niobium, as detailed in Table 1.

[0125] Table 1

[0126]

[0127]

[0128] Preparation Example 28

[0129] Repeat Example 1, except that the H-ZSM-5 molecular sieve in step 1) is replaced with MCM-41 molecular sieve.

[0130] Preparation Example 29

[0131] Repeat Example 1, except that (3-aminopropyl)dimethylmethoxysilane in step 1) is replaced with tetra(dimethylamino)silane, and the amount of tetra(dimethylamino)silane added is 54.6 mL.

[0132] Preparation Example 30

[0133] Repeat Example 1, except that (3-aminopropyl)dimethylmethoxysilane in step 1) is replaced with butyldimethyl(dimethylamino)silane, and the amount of butyldimethyl(dimethylamino)silane added is 48.2 mL.

[0134] Preparation Example 31

[0135] Repeat Example 1, except that (3-aminopropyl)dimethylmethoxysilane in step 1) is replaced with 3-aminopropyltrimethoxysilane, and the amount of 3-aminopropyltrimethoxysilane added is 41.2 mL.

[0136] Preparation Example 32

[0137] Repeat Example 1, except that in step 2), palladium nitrate is replaced with palladium chloride, and the amount of palladium chloride added is 0.77g.

[0138] Preparation Example 33

[0139] Repeat Example 1, except that boric acid is not added in step 2), and the amount of niobium oxalate added is 0.2g.

[0140] Preparation Example 34

[0141] Repeat Example 1, except that niobium oxalate is not added in step 2), and the amount of boric acid added is 0.2g.

[0142] Comparative Example 1

[0143] 1) Add 20g of H-ZSM-5 molecular sieve and 96.8g of chloroplatinic acid to 1000mL of toluene solution, heat to 110℃ and reflux at this temperature for 12h, filter to obtain solid, dry the solid at 80℃, and obtain 19.0g of modified molecular sieve support after drying.

[0144] 2) Add 1g palladium nitrate, 0.09g boric acid, 0.1g niobium oxalate and 1g sodium chloride to 1000mL deionized water, and add 10g of the modified molecular sieve support obtained in step 1). Then sonicate the solution for 30min, soak for 12h after sonication, dry the solution at 80℃ for 24h, and grind the obtained solid into powder to obtain 8.4g of powdered solid.

[0145] 3) The 8.4g powdered solid obtained in step 3) was calcined at 400℃ for 5h while hydrogen was introduced. After calcination, 7.0g hydrogenation catalyst was obtained.

[0146] The hydrogenation catalyst obtained in step 3) is tested, wherein the mass of platinum is 0.60% of the support mass, the mass of the main active component palladium is 1.32% of the support mass, the mass of the secondary active component is 0.27% of the support mass, and the mass ratio of boron to niobium in the secondary active component is 1:1.30.

[0147] Comparative Example 2

[0148] Repeat Comparative Example 1, except that step 1) is replaced with: impregnating H-ZSM-5 molecular sieve with potassium nitrate at 90℃ for 12h, then filtering, washing, drying, and calcining at 300℃ for 2h to obtain the modified molecular sieve carrier.

[0149] Comparative Example 3

[0150] 1) Mix 20g of H-ZSM-5 molecular sieve and 40mL of (3-aminopropyl)dimethylmethoxysilane, add to 1000mL of toluene solution, heat to 110℃ and reflux at this temperature for 12h, filter to obtain solid, dry the solid at 80℃, and after drying, obtain 19.2g of modified molecular sieve support.

[0151] 2) Add 1g palladium nitrate, 0.47g cerium nitrate, 0.1g niobium oxalate and 1g sodium chloride to 1000mL deionized water, and add 10g of the modified molecular sieve support obtained in step 1). Then sonicate the solution for 30min, and after sonication, soak for 12h. Dry the obtained solution at 80℃ for 24h. Grind the obtained solid into powder to obtain 8.8g of powdered solid.

[0152] 3) The 8.8g powdered solid obtained in step 3) was calcined at 400℃ for 5h while hydrogen was introduced. After calcination, 7.2g hydrogenation catalyst was obtained.

[0153] The phenol selective hydrogenation catalyst obtained in step 3) is tested, wherein the mass of the base group is 0.62% of the support mass, the mass of the main active component palladium is 1.28% of the support mass, the mass of the secondary active component is 0.30% of the support mass, and the mass ratio of cerium to niobium in the secondary active component is 1:1.32.

[0154] Comparative Example 4

[0155] Repeat Comparative Example 3, except that in step 2), cerium nitrate was replaced with platinum chloride, and the amount of platinum chloride added was 0.49 g.

[0156] Comparative Example 5

[0157] 1) Mix 20g of H-ZSM-5 molecular sieve and 40mL of (3-aminopropyl)dimethylmethoxysilane, add to 1000mL of toluene solution, heat to 110℃ and reflux at this temperature for 12h, filter to obtain solid, dry the solid at 80℃, and after drying, obtain 19.2g of modified molecular sieve support.

[0158] 2) Add 1g palladium nitrate, 0.09g boric acid, 0.02g sodium nitrate and 1g sodium chloride to 1000mL deionized water, and add 10g of the modified molecular sieve support obtained in step 1). Sonicate the solution for 30min, and after sonication, soak for 12h. Dry the obtained solution at 80℃ for 24h. Grind the obtained solid into powder to obtain 8.5g of powdered solid.

[0159] 3) The 8.5g powdered solid obtained in step 3) was calcined at 400℃ for 5h while hydrogen was introduced. After calcination, 7.0g hydrogenation catalyst was obtained.

[0160] The selective hydrogenation catalyst for phenol obtained in step 3) is tested, wherein the mass of the base group is 0.58% of the support mass, the mass of the main active component palladium is 1.30% of the support mass, the mass of the secondary active component is 0.31% of the support mass, and the mass ratio of boron to sodium in the secondary active component is 1:1.29.

[0161] Comparative Example 6

[0162] Repeat Comparative Example 5, except that sodium nitrate in step 2) is replaced with magnesium chloride, and the amount of magnesium chloride added is 0.02g.

[0163] Comparative Example 7

[0164] Repeat Comparative Example 3, except that in step 2), cerium nitrate is replaced with ammonium dihydrogen phosphate, and the amount of ammonium dihydrogen phosphate added is 0.19g.

[0165] The catalysts prepared in Examples 1-33 and Comparative Examples 1-7 were used in the preparation of cyclohexanone, as follows:

[0166] Step A) is as follows: 100g of dichloromethane, 3g of phenol, and 0.15g of the catalyst prepared in Examples 1-33 and Comparative Examples 1-6 are added to the reaction vessel. The reaction vessel is sealed and evacuated to a vacuum. Nitrogen gas at 1.0MPa is introduced, and the reaction vessel is evacuated to a vacuum state again. The nitrogen gas purging step is repeated 3 times. Then, the air in the vessel is replaced with hydrogen gas. The reaction vessel is evacuated to a vacuum state again, and hydrogen gas is introduced to adjust the pressure to 1.2MPa. The solution in the vessel is heated to 80°C and stirred at 500rpm for 5 hours. After the reaction is completed, the solution is cooled and filtered to obtain cyclohexanone.

[0167] Comparative Example 8

[0168] 10g of citral, 10g of ethanol, and 0.3g of the catalyst prepared in Example 1 were added to the reactor. The air in the reactor was replaced three times each with nitrogen and hydrogen, and the pressure was increased to 1.5 MPa. Stirring was started and the temperature was raised, controlling the reaction temperature at 80°C and the hydrogen pressure at 2.0 MPa during the reaction. After 7 hours, the hydrogen pressure no longer decreased. The reactor was then cooled, the reaction liquid was discharged, and the solvent was removed by distillation to obtain the reaction product. The yield of geraniol was determined to be 76.29%.

[0169] The yields and contents of cyclohexanone in the products obtained by using the catalysts prepared in Examples 1-34 and Comparative Examples 1-7 were tested respectively. The results are shown in Table 2.

[0170] Table 2

[0171]

[0172]

[0173] Based on the above experimental results, it can be seen that the phenol selective hydrogenation catalyst provided by this invention exhibits high selectivity and yield in the preparation of cyclohexanone. Compared with using other compounds to modify the molecular sieve or loading other active components, this invention uses a base-modified molecular sieve and loads palladium as the main active component and boron and / or niobium as secondary active components, while strictly limiting the mass ratio of each substance, so that the prepared catalyst has optimal performance.

Claims

1. A selective hydrogenation catalyst for phenol, characterized in that: The catalyst comprises a support and an active component loaded on the surface of the support; wherein the support is a molecular sieve modified with base groups; the active component comprises a main active component and a secondary active component; the main active component comprises palladium; the secondary active component comprises boron and niobium; The base-modified molecular sieve is either H-ZSM-5 molecular sieve modified with an amino-containing modifier or MCM-41 molecular sieve modified with an amino-containing modifier; the amino-containing modifier is one or more of tris(dimethylamino)silane, butyldimethyl(dimethylamino)silane, tetra(dimethylamino)silane, bis(tert-butylamino)silane, trimethoxy[3-(phenylamino)propyl]silane, 3-aminopropyltrimethoxysilane, and (3-aminopropyl)dimethylmethoxysilane. In the catalyst, the content of the basic group is 0.05% to 1% of the support mass, the content of the main active component is 0.5% to 2% of the support mass, and the content of the secondary active component is 0.1% to 0.5% of the support mass; the mass ratio of boron to niobium in the secondary active component is 1:1 to 1.

7.

2. The catalyst according to claim 1, characterized in that: The amino-containing modifier is 3-aminopropyltrimethoxysilane or (3-aminopropyl)dimethylmethoxysilane.

3. The catalyst according to claim 1 or 2, characterized in that: In the catalyst, the content of the base groups is 0.3% to 0.9% of the support mass, the content of the main active component is 1% to 1.6% of the support mass, and the content of the secondary active component is 0.2% to 0.4% of the support mass; the mass ratio of boron to niobium in the secondary active component is 1:1.2 to 1.

4.

4. A method for preparing a phenol selective hydrogenation catalyst as described in any one of claims 1-3, characterized in that: The preparation method includes the following steps: 1) Add molecular sieve and modifier to solvent I, heat and reflux, filter, and dry the resulting solid to obtain modified molecular sieve support; 2) First, add the main active component precursor, the secondary active component precursor and sodium chloride to solvent II, then add the modified molecular sieve support obtained in step 1), and after sonication, impregnation and drying, grind the solid into powder to obtain powdered solid. 3) The powdered solid obtained in step 2) is calcined in a reducing gas atmosphere to obtain a phenol selective hydrogenation catalyst; The molecular sieve mentioned in step 1) is H-ZSM-5 molecular sieve or MCM-41 molecular sieve; the modifier is one of tris(dimethylamino)silane, butyldimethyl(dimethylamino)silane, tetra(dimethylamino)silane, bis(tert-butylamino)silane, trimethoxy[3-(phenylamino)propyl]silane, 3-aminopropyltrimethoxysilane, and (3-aminopropyl)dimethylmethoxysilane. Step 2) The main active component precursor is one of palladium nitrate, palladium chloride, or palladium acetate; the secondary active component precursor is a mixture of boric acid and niobium oxalate in a mass ratio of 0.7 to 1.5:

1.

5. The preparation method according to claim 4, characterized in that: The modifier mentioned in step 1) is 3-aminopropyltrimethoxysilane or (3-aminopropyl)dimethylmethoxysilane; and / or In step 1), solvent I is one or more of toluene, xylene, and dichloromethane; and / or Step 1) refers to raising the temperature of the solution to 90-130°C; and / or The reflux time mentioned in step 1) is 10~15h; and / or The drying temperature in step 1) is 60~100℃; and / or The solid-liquid ratio of the molecular sieve and modifier mentioned in step 1) is 0.3~3g / mL.

6. The preparation method according to claim 5, characterized in that: Step 1) involves heating the solution to 100-120°C; the reflux time is 11-13 hours; the drying temperature is 70-90°C; and the solid-liquid ratio of the molecular sieve and the modifier is 1.5-2.5 g / mL.

7. The preparation method according to any one of claims 4-6, characterized in that: The precursor of the main active component in step 2) is palladium nitrate; and / or The mass ratio of boric acid to niobium oxalate is 0.8~1.1:1; and / or Solvent II in step 2) is deionized water; and / or Step 2) The ultrasound duration is 20-50 minutes; and / or Step 2) The soaking time is 8-18 hours; and / or Step 2) The drying temperature is 50~100℃; and / or The drying time in step 2) is 16-30 hours; and / or Step 2) The amount of the main active component precursor added is 1%-20% of the mass of the modified molecular sieve support; and / or In step 2), the amount of the precursor of the secondary active component added is 0.3%-3.5% of the mass of the modified molecular sieve support.

8. The preparation method according to claim 7, characterized in that: Step 2) The ultrasonic time is 25-40 min; the impregnation time is 10-14 h; the drying temperature is 70-90℃; the drying time is 20-28 h; the amount of the main active component precursor added is 8%-15% of the mass of the modified molecular sieve carrier; the amount of the secondary active component precursor added is 0.8%-3% of the mass of the modified molecular sieve carrier.

9. The preparation method according to any one of claims 4-6 and 8, characterized in that: Step 3) The roasting temperature is 300~500℃; and / or Step 3) The roasting time is 2-10 hours; and / or The reducing gas in step 3) is hydrogen.

10. The preparation method according to claim 9, characterized in that: Step 3) The roasting temperature is 350~450℃; the roasting time is 4~7h.

11. The preparation method according to any one of claims 4-6, 8, and 10, characterized in that: Step 1) specifically involves: adding molecular sieves and modifiers to toluene, heating to 90-130°C, and refluxing at this temperature for 10-15 hours, filtering to obtain a solid, and drying the solid at 60-100°C to obtain a modified molecular sieve support. and / or Step 2) specifically involves: adding palladium precursor, boron precursor, niobium precursor, and sodium chloride to deionized water, and adding the modified molecular sieve support obtained in step 1); wherein the amount of palladium precursor added is 1%-20%, the amount of boron precursor added is 0.1%-1.5%, and the amount of niobium precursor added is 0.2%-2.0%; then sonicating the solution for 20-50 min, soaking for 8-18 h after sonication, drying the resulting solution at 50-100℃ for 16-30 h, and grinding the resulting solid into powder to obtain a powdered solid; and / or Step 3) specifically involves calcining the powdered solid obtained in step 2) at 300-500°C for 2-10 hours while simultaneously introducing hydrogen gas to obtain a phenol selective hydrogenation catalyst.

12. The preparation method according to claim 11, characterized in that: Step 1) specifically involves: adding molecular sieves and modifiers to toluene, heating to 100-120°C, and refluxing at this temperature for 11-13 hours, filtering to obtain a solid, and drying the solid at 70-90°C to obtain a modified molecular sieve support. and / or Step 2) specifically involves adding palladium precursor, boron precursor, niobium precursor, and sodium chloride to deionized water, along with the modified molecular sieve support obtained in step 1); wherein the amount of palladium precursor added is 8%~15%, the amount of boron precursor added is 0.6%~1.2%, and the amount of niobium precursor added is 0.5%~1.5%; The solution is then sonicated for 25-40 minutes, and after sonication, it is soaked for 10-14 hours. The resulting solution is dried at 70-90℃ for 20-28 hours. The resulting solid is then ground into powder to obtain a powdered solid; and / or Step 3) specifically involves calcining the powdered solid obtained in step 2) at 350~450℃ for 4~7h while simultaneously introducing hydrogen gas to obtain a phenol selective hydrogenation catalyst.

13. A method for applying the phenol selective hydrogenation catalyst according to any one of claims 1-3 or a method for applying the phenol selective hydrogenation catalyst prepared by the preparation method according to any one of claims 4-12, characterized in that: The method includes the following steps: A) Add solvent III, phenol, and a phenol selective hydrogenation catalyst to the reaction vessel, replace the air in the reaction vessel with hydrogen, heat and stir the reaction, cool down after the reaction is complete, filter the reaction liquid in the vessel to obtain cyclohexanone.

14. The application method according to claim 13, characterized in that: Solvent III in step A) is dichloromethane; and / or In step A), the mass ratio of phenol to solvent III is 0.01 to 0.05:1; and / or The molar ratio of the phenol selective hydrogenation catalyst to phenol in step A) is 0.01~0.1:1; and / or Step A) The pressure of the hydrogen gas is 0.2~2 MPa; and / or The heating temperature in step A) is 40~110℃; and / or The stirring speed for the stirring reaction in step A) is 100~1000 rpm; and / or The stirring reaction time in step A) is 1 to 8 hours.

15. The application method according to claim 13 or 14, characterized in that: In step A), the mass ratio of phenol to solvent III is 0.02~0.04:1; the molar ratio of the selective hydrogenation catalyst to phenol is 0.03~0.07:1; the pressure of hydrogen is 0.8~1.4 MPa; the heating temperature is 60~90℃; the stirring speed of the stirring reaction is 300~700 rpm; and the stirring reaction time is 3~6 h.

16. The application method according to claim 13 or 14, characterized in that: Step A) is as follows: Dichloromethane, phenol, and a selective hydrogenation catalyst for phenol are added to the reactor. The reactor is sealed and evacuated to a vacuum. Nitrogen gas at 0.7-1.3 MPa is introduced, and the reactor is evacuated to a vacuum state again. The nitrogen gas purging step is repeated 2-5 times. Then, hydrogen gas is used to replace the air in the reactor. The reactor is evacuated to a vacuum state again, and hydrogen gas is introduced to adjust the pressure to 0.2-2 MPa. The solution in the reactor is heated to 40-110°C and stirred at 100-1000 rpm for 1-8 hours. After the reaction is completed, the reactor is cooled, and the solution in the reactor is filtered to obtain cyclohexanone.

17. The application method according to claim 16, characterized in that: The reaction vessel was evacuated again, and hydrogen gas was introduced to adjust the pressure to 0.8-1.4 MPa. The solution inside the vessel was heated to 60-90°C and stirred at 300-700 rpm for 3-6 hours. After the reaction was completed, the vessel was cooled and the solution inside the reaction vessel was filtered to obtain cyclohexanone.

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