Catalyst and process for its preparation, process for the preparation of 2,2,6,6-tetramethyl-4-piperidinol

Abstract

The application provides a catalyst and a preparation method thereof, and a preparation method of 2,2,6,6-tetramethyl-4-piperidinol, and relates to the technical field of catalysts. The catalyst comprises a carrier and a transition metal supported on the carrier, and the carrier is an ordered mesoporous titanosilicate material internally modified with nitrogen-carbon material and containing trivalent titanium. The carrier in the catalyst of the application is an ordered mesoporous titanosilicate material internally modified with nitrogen-carbon material and containing trivalent titanium, the nitrogen in the nitrogen-carbon material can provide a lone pair of electrons, which is a Lewis base site, and the trivalent titanium is in an electron-deficient state, which is a Lewis acid center, and the two form a hindered Lewis acid-base pair in the ordered mesoporous confined space. The hindered Lewis acid-base pair formed in the catalyst is beneficial to anchoring the transition metal active component and promoting the adsorption and activation of the reaction substrate tetramethylpiperidone, thereby helping to improve the reaction kinetics of the catalytic hydrogenation process.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, and more specifically, to a catalyst and its preparation method, and a method for preparing 2,2,6,6-tetramethyl-4-piperidinol. Background Technology

[0002] With the booming development of the plastic products market, the demand for plastic additives is increasing. Among them, hindered amine (HALS) light stabilizers and their intermediates have good market prospects because they can effectively prevent and inhibit the photoaging process of polymer materials and extend their service life.

[0003] The structural formula of HALS is Because there are four methyl groups on the carbon atoms connected to both sides, the nitrogen atom on its piperidine ring and the groups attached to it are sterically hindered by the four methyl groups, hence the name hindered amine compounds. Hindered amine light stabilizers were first discovered by Sankyo Corporation of Japan in the mid-1970s. Subsequently, Ciba of Switzerland developed many products in the HALS field and is in a leading position. Their light stabilizing effect is 2-4 times that of traditional adsorption-type light stabilizers, they have good compatibility with many resins, and their properties do not change with the thickness of the product. Their mechanism of action mainly involves three ways: quenching high-energy excited states such as singlet oxygen, decomposing peroxides present and accumulated in the polymer, and capturing polymer free radicals and alkoxy free radicals, thereby slowing down the photo-aging degradation rate of polymer materials, extending the material's service life, and broadening the application scenarios and scope of the material.

[0004] Tetramethylpiperidone (2,2,6,6-tetramethyl-4-piperidone) is the only known precursor for hindered amine light stabilizers. However, it is unstable at room temperature and easily discolors upon prolonged exposure to air, changing from milky white to pale yellow or even brownish-red, limiting its applications. Therefore, existing hindered amine light stabilizers on the market are typically derived from tetramethylpiperidone through hydrogenation reduction to obtain tetramethylpiperidol (2,2,6,6-tetramethyl-4-piperidol) as an intermediate. Tetramethylpiperidol has a hydroxyl structure and can form ester-like hindered amine light stabilizers with long-chain fatty acids. Ciba's Tinuvin 770 and Tinuvin 774 hindered amine light stabilizers are both based on tetramethylpiperidol. In addition, tetramethylpiperidol can also be used in the biopharmaceutical industry as an antioxidant or free radical scavenger, offering some protection against liver and kidney damage. It has high commercial value in both industrial and pharmaceutical fields.

[0005] Currently, there are three main methods for synthesizing tetramethylpiperidinol from tetramethylpiperidone: catalytic hydrogenation reduction, chemical reduction, and electrochemical methods. Chemical reduction often uses sodium borohydride or aluminum isopropoxide as reducing agents, but these are expensive and require complex post-reaction processing, making them unsuitable for large-scale industrial production. Electrochemical reduction uses complex electrolytic cells and consumes high energy, so it is generally not used industrially. Therefore, catalytic hydrogenation is currently the main method for industrial production, and its reaction formula is... The design and development of high-performance hydrogenation catalysts is key to the reaction.

[0006] The Chinese literature titled "Study on the Synthesis of 2,2,6,6-Tetramethyl-4-piperidinol by Catalytic Hydrogenation under Atmospheric Pressure" (Wang Duolu, Zhang Zepeng, Chen Ligong, et al., Chemical Industry and Engineering, 1998(03):22-26) uses Raney nickel as a catalyst and a mixture of isopropanol and water as a solvent for hydrogenation under atmospheric pressure. Under reaction conditions of 80℃, the yield of tetramethylpiperidinol is 97%. However, this method is carried out in an atmospheric pressure hydrogenation device with the equipment in an open state, which will cause H2 to escape, resulting in H2 waste and posing a significant safety hazard.

[0007] The research report titled "A continuous process for the production of 2,2,6,6-tetramethylpiperidin-4-ol catalyzed by Cu–Cr / γ-Al2O3" (Catalysis Communications, 2010, 11, 960-963) established a continuous production process for 2,2,6,6-tetramethyl-4-piperidinol using a Cu-Cr catalyst supported on γ-Al2O3. However, the yield was only about 90%, and under the reaction conditions, Cu was prone to agglomeration, which deactivated the catalyst and made it difficult to meet the inherent requirement of long-term stable operation of continuous fixed-bed reaction processes.

[0008] Currently, in industrial production, piperidinol is prepared by hydrogenation in a batch reactor using Raney nickel as a catalyst. Due to the poor stability and susceptibility to spontaneous combustion of Raney nickel, the loading and unloading of the catalyst in this process must be carried out under strict inert gas protection. Furthermore, production can only be carried out intermittently, resulting in batch-to-batch variations in process parameters, leading to inconsistent product quality, low production efficiency, and significant safety hazards. In addition, traditional batch reactors suffer from low efficiency in the transfer of gaseous hydrogen to the liquid catalyst surface, potentially affecting the reaction rate and selectivity. Fixed-bed catalytic hydrogenation, with its advantages of continuous feed production, high mass transfer efficiency, small scale-up effect, environmental safety, and simple operation, holds great promise. However, current fixed-bed catalytic hydrogenation of piperidinone to piperidinol uses relatively simple catalysts, mostly employing γ-Al₂O₃ as a support to load the active metal component for hydrogenation, resulting in high energy consumption, poor catalytic activity, and short catalyst lifetime. Existing supported catalysts suffer from drawbacks such as underdeveloped pore structures, small active surface areas, large particle sizes of active components, and a limited number of exposed surface-coordinated unsaturated metal atoms. These disadvantages hinder mass transfer and reactant adsorption and activation, leading to sluggish kinetics in the hydrogenation of piperidinone. Furthermore, when the catalyst support is highly acidic, it readily undergoes strong adsorption with tetramethylpiperidinone. The bonding between NH4+ and the two tertiary carbon atoms weakens the carbon-nitrogen bond, causing the CN-C bond between the secondary amine group and the two adjacent carbon atoms to break, generating a series of byproducts such as 2,6-dimethyl-4-heptanone, making it difficult to improve the yield. Summary of the Invention

[0009] The main objective of this invention is to provide a catalyst and its preparation method, as well as a method for preparing 2,2,6,6-tetramethyl-4-piperidinol, to solve the problem of low catalyst selectivity in the prior art for the catalytic hydrogenation preparation of 2,2,6,6-tetramethyl-4-piperidinol.

[0010] To achieve the above objectives, according to one aspect of the present invention, a catalyst is provided comprising a support and a transition metal supported on the support, wherein the support is an ordered mesoporous titanium-silicon material internally modified with nitrogen-carbon material and containing trivalent titanium.

[0011] Furthermore, the mass percentage of nitrogen-carbon materials in the above-mentioned carrier is 3.0~15.0%; and / or, the molar percentage of trivalent titanium in the total titanium in the carrier is 0.5~5.0%; and / or, the loading of transition metal is 3~20% of the carrier mass; and / or, the molar ratio of silicon to titanium in the carrier is 1:(0.05~0.5).

[0012] Furthermore, the average pore size of the aforementioned support is 4.0~7.0 nm; and / or, the specific surface area of ​​the support is 500~700 m². 2 / g; and / or, the particle size of the catalyst is 20~40 mesh.

[0013] According to another aspect of the present invention, a method for preparing the aforementioned catalyst is provided, the method comprising: step S1, mixing an aqueous solution containing a silicon source and a titanium source with an aqueous solution containing a surfactant, and then sequentially performing pH adjustment, aging treatment and solid-liquid separation to obtain a precursor material; step S2, sequentially performing plasma treatment on the precursor material to form a nitrogen-carbon material and reduction treatment to form trivalent titanium to obtain an ordered mesoporous titanium-silicon material internally modified with trivalent titanium; step S3, mixing the ordered mesoporous titanium-silicon material internally modified with trivalent titanium, a transition metal source and water, and then sequentially performing drying and calcination treatments to obtain the catalyst.

[0014] Further, in step S1 above, the molar ratio of silicon source, titanium source and surfactant is 1:(0.05~0.5):(0.01~0.2); and / or, the micelle concentration in the aqueous solution containing surfactant is 0.01~0.2mol / L; and / or, the pH value of the solution after pH adjustment is 7~9; and / or, the aging treatment temperature is 60~100℃, and the aging treatment time is 4~8h.

[0015] Furthermore, in step S2 above, the plasma treatment power is 10~100W, the plasma treatment time is 10~60min; and / or, the reduction treatment temperature is 250~450℃, the reduction treatment time is 2~6h, and the reduction treatment heating rate is 5~15℃ / min.

[0016] Furthermore, in step S3 above, the calcination temperature is 300~500℃, the calcination time is 2~4h, and the heating rate of the calcination is 5~15℃ / min.

[0017] Further, the silicon source is selected from sodium metasilicate and / or sodium silicate; and / or, the titanium source is selected from any one or more of titanium sulfate, titanium oxysulfate, and titanium nitrate; and / or, the surfactant has the general formula [NR 1 R 2 R 3 R 4 X, where R 1 C 12 ~C 20 straight-chain alkyl, R 2 R 3 and R 4 Each is an alkyl group of C1 to C4, and X is a halogen atom; and / or, the transition metal source is selected from any one or more of Pd source, Pt source, Ru source, Co source, Ni source, Cu source and Cr source.

[0018] According to another aspect of the present invention, a method for preparing 2,2,6,6-tetramethyl-4-piperidinol is provided, the method comprising: loading the aforementioned catalyst into a continuous fixed-bed reactor, and introducing tetramethylpiperidone and hydrogen gas to carry out a hydrogenation catalytic reaction to obtain 2,2,6,6-tetramethyl-4-piperidinol.

[0019] Furthermore, the above preparation method also includes: activating the catalyst before carrying out the hydrogenation catalytic reaction, wherein the activation temperature is 200~500℃ and the activation time is 1~5h.

[0020] Applying the technical solution of this invention, the catalyst support in this application is an ordered mesoporous titanium-silicon material internally modified with nitrogen-carbon material and containing trivalent titanium. Nitrogen in the nitrogen-carbon material provides lone pairs of electrons, acting as Lewis basic sites, while trivalent titanium is electron-deficient, acting as Lewis acidic centers. These two form hindered Lewis acid-base pairs within the confined space of the ordered mesoporous structure. The hindered Lewis acid-base pairs formed in this catalyst are beneficial for anchoring the transition metal active component and promoting the adsorption and activation of the reaction substrate tetramethylpiperidone, thereby contributing to improved reaction kinetics in the catalytic hydrogenation process. Surface defects formed by trivalent titanium can induce strong metal-support interactions between the transition metal and the mesoporous pore walls, thereby improving the dispersion and stability of the transition metal in the mesoporous channels, exposing more reactive sites, and contributing to improved catalyst activity and selectivity. The confined space formed by the ordered mesoporous structure can inhibit the aggregation of transition metals in the catalytic reaction, contributing to improved catalyst lifespan. Furthermore, a large number of transition metal-nitrogen-carbon interfaces are generated between the nitrogen-carbon material on the mesoporous pore walls and the active transition metal, which can lower the hydrogen dissociation energy barrier and further improve the conversion efficiency of tetramethylpiperidone. Therefore, the catalyst of this application has high selectivity in the catalytic hydrogenation of tetramethylpiperidone to 2,2,6,6-tetramethyl-4-piperidinol, which helps to improve the yield of 2,2,6,6-tetramethyl-4-piperidinol. Attached Figure Description

[0021] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0022] Figure 1 A TEM image of the carrier in Embodiment 1 of this application is shown;

[0023] Figure 2 The gas chromatogram of 2,2,6,6-tetramethyl-4-piperidinol in Example 1 of this application is shown. Detailed Implementation

[0024] Terminology Explanation: Total titanium in this application refers to the sum of trivalent and tetravalent titanium.

[0025] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] As analyzed in the background section of this application, the prior art suffers from low catalyst selectivity in the catalytic hydrogenation preparation of 2,2,6,6-tetramethyl-4-piperidinol. To address this issue, this application provides a catalyst and its preparation method, as well as a method for preparing 2,2,6,6-tetramethyl-4-piperidinol.

[0027] In a typical embodiment of this application, a catalyst is provided, comprising a support and a transition metal supported on the support, wherein the support is an ordered mesoporous titanium-silicon material internally modified with nitrogen-carbon material and containing trivalent titanium.

[0028] The catalyst in this application utilizes an ordered mesoporous titanium-silicon material internally modified with nitrogen-carbon material and containing trivalent titanium. Nitrogen in the nitrogen-carbon material provides lone pairs of electrons, acting as Lewis basic sites, while trivalent titanium is electron-deficient, acting as Lewis acidic centers. These two elements form a hindered Lewis acid-base pair within the confined space of the ordered mesoporous structure. This hindered Lewis acid-base pair facilitates the anchoring of the transition metal active component and promotes the adsorption and activation of the substrate tetramethylpiperidone, thereby enhancing the reaction kinetics of the catalytic hydrogenation process. Surface defects formed by trivalent titanium induce strong metal-support interactions between the transition metal and the mesoporous pore walls, improving the dispersion and stability of the transition metal within the mesoporous channels, exposing more reactive sites, and thus enhancing the catalyst's activity and selectivity. The confined space created by the ordered mesoporous structure inhibits the aggregation of the transition metal during the catalytic reaction, contributing to a longer catalyst lifespan. Furthermore, the nitrogen-carbon material on the mesoporous pore walls generates numerous transition metal-nitrogen-carbon interfaces with the active transition metal, lowering the hydrogen dissociation barrier and further improving the conversion efficiency of tetramethylpiperidone. Therefore, the catalyst of this application has high selectivity in the catalytic hydrogenation of tetramethylpiperidone to 2,2,6,6-tetramethyl-4-piperidinol, which helps to improve the yield of 2,2,6,6-tetramethyl-4-piperidinol.

[0029] In some embodiments of this application, the mass percentage of nitrogen-carbon materials in the above-mentioned carrier is 3.0~15.0%; and / or, the molar percentage of trivalent titanium in the total titanium in the carrier is 0.5~5.0%; and / or, the loading of transition metal is 3~20% of the carrier mass, specifically 3%, 5%, 8%, 10%, 13%, 15%, 17%, 20% and a range between two values; and / or, the molar ratio of silicon to titanium in the carrier is 1:(0.05~0.5), preferably 1:(0.1~0.2).

[0030] Controlling the mass ratio of nitrogen and carbon materials in the support within the aforementioned range helps provide an appropriate amount of Lewis basic sites, forming stable adsorption complexes with transition metals and substrates, promoting substrate activation and hydrogen dissociation, thereby improving catalytic activity. Controlling the molar percentage of trivalent titanium in the total titanium in the support within the aforementioned range helps form an appropriate amount of surface defects. These defects not only attract and stabilize transition metals but also promote rapid hydrogen dissociation, accelerating the kinetics of the hydrogenation reaction and improving conversion and reaction rate. Controlling the loading percentage of transition metals within the aforementioned range helps ensure sufficient catalytic activity while avoiding agglomeration caused by transition metal overloading. Controlling the molar ratio of silicon to titanium in the support within the aforementioned range helps to give the support a suitable pore structure and acidity, which is beneficial for transition metal anchoring and helps reduce side reactions, thereby improving the selectivity of the target product.

[0031] In some embodiments of this application, the average pore size of the carrier is 4.0~7.0 nm; and / or, the specific surface area of ​​the carrier is 500~700 m². 2 / g; and / or, the particle size of the catalyst is 20~40 mesh.

[0032] The pore size of mesoporous materials affects the transport efficiency of reactant molecules and hydrogen within the catalyst channels. Controlling the average pore size of the support within the aforementioned range helps improve the transport efficiency of reactant molecules and hydrogen, thereby contributing to increased reaction rate and conversion. Furthermore, a suitable pore size promotes the uniform dispersion of active metal species within the channels, reducing metal agglomeration and thus enhancing the catalytic activity and selectivity of the catalyst. Controlling the specific surface area of ​​the support within the aforementioned range helps improve the structural stability of the catalyst while simultaneously increasing its catalytic activity. Controlling the particle size of the catalyst within the aforementioned range helps reduce bed resistance, improve reactor packing efficiency, and facilitates continuous production.

[0033] In some embodiments of this application, the pore length of the above-mentioned carrier is 150~200nm.

[0034] In another typical embodiment of this application, a method for preparing the aforementioned catalyst is provided, the method comprising: step S1, mixing an aqueous solution containing a silicon source and a titanium source with an aqueous solution containing a surfactant, and then sequentially performing pH adjustment, aging treatment and solid-liquid separation to obtain a precursor material; step S2, sequentially performing plasma treatment on the precursor material to form a nitrogen-carbon material and reduction treatment to form trivalent titanium, to obtain an ordered mesoporous titanium-silicon material internally modified with trivalent titanium; step S3, mixing the ordered mesoporous titanium-silicon material internally modified with trivalent titanium, a transition metal source and water, and then sequentially performing drying and calcination treatments to obtain the catalyst.

[0035] In step S1, a surfactant is used as a soft template agent. The silicon and titanium sources are hydrolyzed under near-neutral or weakly alkaline conditions. The entire reaction does not require a high-temperature crystallization process, making the operation simple. The surfactant forms micelles, and the silicon and titanium sources hydrolyze on the surface of the micelle template agent to generate silicic acid and titanic acid. In step S2, the surfactant is decomposed, carbonized, and nitrogen-doped under the action of inert gas plasma to generate a nitrogen-carbon material, releasing an ordered mesoporous structure while internally modifying the pore walls of the titanium-silicon mesoporous material. In addition, after treatment in a reducing atmosphere, the framework titanium embedded in the pore walls of the ordered mesoporous silica is partially reduced to trivalent titanium. In step S3, the ordered mesoporous titanium-silicon material with internal modification of the nitrogen-carbon material and containing trivalent titanium, a transition metal source, and water are mixed and then subjected to drying and calcination treatments in sequence, so that the transition metal is loaded on the ordered mesoporous titanium-silicon material with internal modification of the nitrogen-carbon material and containing trivalent titanium to form a catalyst.

[0036] In some embodiments of this application, in step S1 above, the molar ratio of silicon source, titanium source and surfactant is 1:(0.05~0.5):(0.01~0.2); and / or, the micelle concentration in the aqueous solution containing surfactant is 0.01~0.2mol / L; and / or, the pH value of the solution after pH adjustment is 7~9; and / or, the aging treatment temperature is 60~100℃, and the aging treatment time is 4~8h.

[0037] Controlling the molar ratio of silicon source, titanium source, and surfactant within the aforementioned range helps promote the formation of ordered mesoporous structures, thereby improving the catalytic activity and selectivity of the catalyst. Controlling the micelle concentration in the surfactant-containing aqueous solution within the aforementioned range helps control the pore size and specific surface area of ​​the ordered mesoporous titanium-silicon material within suitable ranges, thereby improving the catalytic activity and structural stability of the catalyst. Controlling the pH value of the solution after pH adjustment within the aforementioned range helps promote the hydrolysis of silicon and titanium sources on the template agent micelle surface to generate silicic acid and titanic acid. Controlling the temperature and time of the aging treatment within the aforementioned range helps promote the maturation and stabilization of the pore structure.

[0038] In some embodiments of this application, the surfactant is dissolved in water and stirred at 30-60°C for 0.5-2 hours to form an aqueous solution containing the surfactant; the aqueous solution containing silicon source and titanium source is slowly added dropwise to the aqueous solution containing surfactant and then stirred at 30-60°C for 1-2 hours to mix, so that the silicon source and titanium source are in full contact with the hydrophilic end of the micelles.

[0039] In some embodiments of this application, step S1 further includes washing the solid with water several times after solid-liquid separation until the sample is neutral, and then drying it overnight in an oven at 60~120°C to obtain the precursor material.

[0040] In some embodiments of this application, in step S2 above, the power of plasma treatment is 10~100W, the plasma treatment time is 10~60min; and / or, the temperature of reduction treatment is 250~450℃, the reduction treatment time is 2~6h, and the heating rate of reduction treatment is 5~15℃ / min.

[0041] Controlling the power and time of plasma treatment within the aforementioned ranges helps to maintain the appropriate mass ratio of nitrogen and carbon materials in the support, thereby facilitating the formation of suitable Lewis basic sites and ultimately improving the catalytic activity and selectivity of the catalyst. Controlling the temperature, time, and heating rate of the reduction treatment within the aforementioned ranges helps to maintain the appropriate content of trivalent titanium, which is beneficial for anchoring transition metal active components and promoting the adsorption and activation of the reaction substrate tetramethylpiperidinone, thus contributing to improved reaction kinetics in the catalytic hydrogenation process.

[0042] In some embodiments of this application, the gas used for plasma treatment is selected from any one or more of nitrogen, argon, and helium; a 5-30% hydrogen-argon mixed gas is introduced for reduction treatment.

[0043] In some embodiments of this application, in step S3 above, the calcination temperature is 300~500℃, the calcination time is 2~4h, and the heating rate of the calcination is 5~15℃ / min.

[0044] Controlling the temperature, time, and heating rate of the calcination process within the above range helps to remove residual moisture and organic matter without damaging the pore structure of the ordered mesoporous titanium silicon material. This enhances the strong interaction between the active metal component and the carrier material, promoting the dispersion and stability of metal species.

[0045] In some embodiments of this application, the mixing in step S3 above is ultrasonic dispersion for 1-2 hours; the drying temperature is 80-100°C.

[0046] To enhance the synergistic effect among the components and further improve the catalytic activity and selectivity of the catalyst, in some embodiments of this application, the silicon source is selected from sodium metasilicate and / or sodium silicate; and / or, the titanium source is selected from any one or more of titanium sulfate, titanium oxysulfate, and titanium nitrate; and / or, the surfactant has the general formula [NR 1 R 2 R 3 R 4 X, where R 1 C 12 ~C 20 straight-chain alkyl, R 2 R 3 and R 4 Each of the components is an alkyl group of C1 to C4, and X is a halogen atom, preferably a bromine atom or a chlorine atom. Preferably, the surfactant is selected from hexadecyltrimethylammonium bromide or hexadecyltrimethylammonium chloride; and / or, the transition metal source is selected from any one or more of Pd source, Pt source, Ru source, Co source, Ni source, Cu source and Cr source.

[0047] Including but not limited to, the Pd source is selected from palladium acetate or palladium nitrate, the Pt source is selected from platinum acetate or platinum nitrate, the Ru source is selected from ruthenium acetate or ruthenium nitrate, the Co source is selected from cobalt acetate or cobalt nitrate, the Ni source is selected from nickel acetate or nickel nitrate, the Cu source is selected from copper acetate or copper nitrate, and the Cr source is selected from chromium acetate or chromium nitrate.

[0048] In another typical embodiment of this application, a method for preparing 2,2,6,6-tetramethyl-4-piperidinol is provided. The method includes: loading the aforementioned catalyst into a continuous fixed-bed reactor, and introducing tetramethylpiperidone and hydrogen gas to carry out a hydrogenation catalytic reaction to obtain 2,2,6,6-tetramethyl-4-piperidinol.

[0049] Since the catalyst of this application was used in the preparation of 2,2,6,6-tetramethyl-4-piperidinol, the yield of 2,2,6,6-tetramethyl-4-piperidinol is high.

[0050] In some embodiments of this application, the above preparation method further includes: activating the catalyst before carrying out a hydrogenation catalytic reaction, wherein the activation temperature is 200~500℃ and the activation time is 1~5h.

[0051] Activation treatment reduces the active metal in the catalyst from the oxidized state to the metallic state, which helps to improve catalytic activity, optimize metal-support interactions, improve catalyst structure, and enhance reaction selectivity.

[0052] In some embodiments of this application, a reducing gas (hydrogen or a 25-30% hydrogen-argon mixture) is introduced into the catalyst for activation treatment.

[0053] In some embodiments of this application, the temperature of the above-mentioned hydrogenation catalytic reaction is 80~120°C; the hydrogen pressure is 0.5~3MPa.

[0054] The beneficial effects of this application will be further illustrated below with reference to the embodiments.

[0055] Example 1

[0056] S1, 0.05 mol of cetyltrimethylammonium bromide (CTAB) was dissolved in 1 L of deionized water and stirred at 45 °C for 1 h. The surfactant self-assembled to form a low-concentration micelle solution with a concentration of 0.05 mol / L.

[0057] S2, a mixed aqueous solution containing 1 mol sodium metasilicate and 0.15 mol titanium oxysulfate was slowly added dropwise to the above micelle solution, and the mixture was stirred at 45°C for 1.5 h to ensure that the titanium silicon precursor was in full contact with the hydrophilic end of the micelle. Then, the pH of the solution was adjusted to 8 with 5 mol / L hydrochloric acid to promote the hydrolysis of silicon and titanium sources on the surface of the template agent micelle to generate silicic acid and titanium acid. The mixture was then heated to 80°C and aged for 6 h to obtain a milky white suspension.

[0058] S3, the above milky white suspension was filtered to obtain a white solid and washed several times with deionized water until the sample was neutral. The sample was then dried in an oven at 90°C overnight to obtain the precursor material.

[0059] S4. The precursor material was treated with argon plasma for 30 min at a power of 60 W. The sample was then reduced in a 10% hydrogen-argon mixture at a rate of 5 °C / min to 400 °C for 4 h. After reduction, it was allowed to cool naturally to room temperature. This yielded an ordered mesoporous titanium-silicon material with internal modification to nitrogen-carbon material and containing trivalent titanium. This material was used as a support. Thermogravimetric analysis was used to measure the mass percentage of nitrogen-carbon material in the support, which was calculated to be 8.0%. X-ray photoelectron spectroscopy was used to measure the molar percentage of trivalent titanium in the total titanium in the support, which was calculated to be 3.0%. Gas adsorption analysis was used to measure the average pore size of the support, which was 5.8 nm, and the specific surface area of ​​the support was 620 m². 2 / g;

[0060] S5. Add 10% (by total metal weight) of nickel nitrate (based on the mass of ordered mesoporous titanium-silicon material containing trivalent titanium and modified with nitrogen-carbon material) to a beaker and disperse and dissolve it in 200 mL of deionized water. Then add the ordered mesoporous titanium-silicon material containing trivalent titanium and modified with nitrogen-carbon material and ultrasonically disperse it for 1 h. Then evaporate the solvent at 80 °C to remove it. The dried solid is calcined in argon at 300 °C at 5 °C / min for 4 h to obtain the catalyst powder.

[0061] S6. The catalyst powder was compressed, crushed, and sieved through a 20-40 mesh to obtain catalyst particles. 20g of the catalyst was loaded into a fixed-bed reactor, and hydrogen was introduced to reduce and activate it at 500℃ for 1h. When the temperature of the reaction bed dropped to 100℃ and the H2 pressure rose to 1MPa, a tetramethylpiperidone solution (ethanol:tetramethylpiperidone = 10:1, mass ratio) was introduced at a feed rate of 2.0g / min, and hydrogen was introduced at a flow rate of 15ml / min. The reaction products were detected by gas chromatography.

[0062] Example 2

[0063] The difference from Example 1 is that, in S1, 0.01 mol of hexadecyltrimethylammonium bromide (CTAB) is dissolved in 1 L of deionized water and stirred at 30 °C for 0.5 h, and the surfactant self-assembles to form a low-concentration micelle solution with a concentration of 0.01 mol / L.

[0064] S2, a mixed aqueous solution containing 1 mol sodium metasilicate and 0.05 mol titanium oxysulfate was slowly added dropwise to the above micelle solution, and the mixture was stirred at 30°C for 1 h to ensure that the titanium silicon precursor was in full contact with the hydrophilic end of the micelle. Then, the pH of the solution was adjusted to 7 with 5 mol / L hydrochloric acid to promote the hydrolysis of silicon source and titanium source on the surface of template agent micelle to generate silicic acid and titanium acid. The mixture was then heated to 60°C and aged for 8 h to obtain a milky white suspension.

[0065] S3, the above milky white suspension was filtered to obtain a white solid and washed several times with deionized water until the sample was neutral. The sample was then dried in an oven at 60°C overnight to obtain the precursor material.

[0066] S4. The precursor material was treated with argon plasma for 10 min at a power of 100 W. The sample was then reduced in a 5% hydrogen-argon mixture at a rate of 5 °C / min to 250 °C for 6 h. After reduction, it was allowed to cool naturally to room temperature. This yielded an ordered mesoporous titanium-silicon material with internal modification to nitrogen-carbon material and containing trivalent titanium. The nitrogen-carbon material accounted for 3.0% of the mass of the support, and the trivalent titanium accounted for 0.5% of the total titanium in the support. The average pore size of the support was 7.0 nm, and the specific surface area was 500 m². 2 / g;

[0067] S5, add 20% (by total metal weight) of copper nitrate (internal modification of nitrogen-carbon material and containing trivalent titanium) of ordered mesoporous titanium-silicon material to a beaker and disperse and dissolve it in 200 mL of deionized water. Then add the internal modification of nitrogen-carbon material and containing trivalent titanium and disperse it ultrasonically for 2 h. Then evaporate the solvent at 100 °C to remove it. The dried solid is calcined in argon at 15 °C / min to 500 °C for 2 h to obtain the catalyst powder.

[0068] S6. The catalyst powder was compressed, crushed, and sieved through a 20-40 mesh to obtain catalyst particles. 20g of the catalyst was loaded into a fixed-bed reactor, and hydrogen was introduced to reduce and activate it at 350℃ for 5h. When the temperature of the reaction bed dropped to 120℃ and the H2 pressure rose to 2MPa, a tetramethylpiperidone solution (ethanol:tetramethylpiperidone = 10:1, mass ratio) was introduced at a feed rate of 2.0g / min, and hydrogen was introduced at a flow rate of 15ml / min. The reaction products were detected by gas chromatography.

[0069] Example 3

[0070] The difference from Example 1 is that, in S1, 0.2 mol of hexadecyltrimethylammonium bromide (CTAB) was dissolved in 1 L of deionized water and stirred at 60 °C for 2 h, and the surfactant self-assembled to form a low-concentration micelle solution with a concentration of 0.2 mol / L.

[0071] S2, a mixed aqueous solution containing 1 mol sodium metasilicate and 0.5 mol titanium oxysulfate was slowly added dropwise to the above micelle solution, and the mixture was stirred at 60°C for 2 h to ensure that the titanium silicon precursor was in full contact with the hydrophilic end of the micelle. Then, the pH of the solution was adjusted to 9 with 12 mol / L hydrochloric acid to promote the hydrolysis of silicon source and titanium source on the surface of template agent micelle to generate silicic acid and titanium acid. The mixture was then heated to 100°C and aged for 4 h to obtain a milky white suspension.

[0072] S3, the above milky white suspension was filtered to obtain a white solid and washed several times with deionized water until the sample was neutral. The sample was then placed in an oven at 120°C and dried overnight to obtain the precursor material.

[0073] S4. The precursor material was treated with argon plasma for 60 min at a power of 50 W. The sample was then reduced in a 30% hydrogen-argon mixture at a temperature increased to 450 °C at a rate of 15 °C / min for 2 h. After reduction, the sample was allowed to cool naturally to room temperature. This yielded an ordered mesoporous titanium-silicon material with internal modification to nitrogen-carbon material and containing trivalent titanium. The nitrogen-carbon material accounted for 15.0% of the mass of the support, and the trivalent titanium accounted for 5.0% of the total titanium in the support. The average pore size of the support was 4.0 nm, and the specific surface area was 700 m². 2 / g;

[0074] S5, add 15% (by weight of total metal) of cobalt nitrate (based on total metal content) of ordered mesoporous titanium silicon material with internal modification of nitrogen-carbon material and containing trivalent titanium to a beaker, and disperse and dissolve it in 200 mL of deionized water. Then add the ordered mesoporous titanium silicon material with internal modification of nitrogen-carbon material and containing trivalent titanium and ultrasonically disperse it for 1.5 h. Then evaporate the solvent at 90 °C to remove it. The dried solid is calcined in argon at 10 °C / min to 400 °C for 2 h to obtain the catalyst powder.

[0075] S6. The catalyst powder was compressed, crushed, and sieved through a 20-40 mesh to obtain catalyst particles. 20g of the catalyst was loaded into a fixed-bed reactor, and hydrogen was introduced to reduce and activate it at 350℃ for 5h. When the temperature of the reaction bed dropped to 110℃ and the H2 pressure rose to 3MPa, a tetramethylpiperidone solution (ethanol:tetramethylpiperidone = 10:1, mass ratio) was introduced at a feed rate of 2.0g / min, and hydrogen was introduced at a flow rate of 15ml / min. The reaction products were detected by gas chromatography.

[0076] Example 4

[0077] The difference from Example 1 is that, in S1, 0.1 mol of hexadecyltrimethylammonium bromide (CTAB) is dissolved in 1 L of deionized water and stirred at 50 °C for 1.5 h, and the surfactant self-assembles to form a low-concentration micelle solution with a concentration of 0.1 mol / L.

[0078] S2, a mixed aqueous solution containing 1 mol sodium metasilicate and 0.3 mol titanium oxysulfate was slowly added dropwise to the above micelle solution, and the mixture was stirred at 50°C for 1 h to ensure that the titanium silicon precursor was in full contact with the hydrophilic end of the micelle. Then, the pH of the solution was adjusted to 7.5 with 8 mol / L hydrochloric acid to promote the hydrolysis of silicon and titanium sources on the surface of the template agent micelle to generate silicic acid and titanium acid. The mixture was then heated to 70°C and aged for 6 h to obtain a milky white suspension.

[0079] S3, the above milky white suspension was filtered to obtain a white solid and washed several times with deionized water until the sample was neutral. The sample was then dried in an oven at 100°C overnight to obtain the precursor material.

[0080] S4. The precursor material was treated with argon plasma for 40 min at a power of 60 W. The sample was then reduced in a 15% hydrogen-argon mixture at a rate of 5 °C / min to 300 °C for 4 h. After reduction, it was allowed to cool naturally to room temperature. This yielded an ordered mesoporous titanium-silicon material with internal modification to nitrogen-carbon material and containing trivalent titanium. The nitrogen-carbon material accounted for 10% of the mass of the support, and the trivalent titanium accounted for 3.5% of the total titanium in the support. The average pore size of the support was 5.5 nm, and the specific surface area was 660 m². 2 / g;

[0081] S5, add 20% (by weight of total metal) of ordered mesoporous titanium silicon material containing trivalent titanium modified with nitrogen-carbon material to a beaker, and disperse and dissolve it in 200 mL of deionized water. Then add the ordered mesoporous titanium silicon material containing trivalent titanium modified with nitrogen-carbon material and ultrasonically disperse it for 2 h. Then evaporate the solvent at 95 °C to remove it. The dried solid is calcined in argon at 10 °C / min to 450 °C for 3 h to obtain the catalyst powder.

[0082] S6. The catalyst powder was compressed, crushed, and sieved through a 20-40 mesh to obtain catalyst particles. 20g of the catalyst was loaded into a fixed-bed reactor, and hydrogen was introduced to reduce and activate it at 450℃ for 3h. When the temperature of the reaction bed dropped to 95℃ and the H2 pressure rose to 3MPa, a tetramethylpiperidone solution (ethanol:tetramethylpiperidone = 10:1, mass ratio) was introduced at a feed rate of 2.0g / min, and hydrogen was introduced at a flow rate of 15ml / min. The reaction products were detected by gas chromatography.

[0083] Example 5

[0084] The difference from Example 1 is that, in S1, 0.15 mol of hexadecyltrimethylammonium bromide (CTAB) was dissolved in 1 L of deionized water and stirred at 55 °C for 2 h, and the surfactant self-assembled to form a low-concentration micelle solution with a concentration of 0.15 mol / L.

[0085] S2, a mixed aqueous solution containing 1 mol sodium metasilicate and 0.2 mol titanium oxysulfate was slowly added dropwise to the above micelle solution, and the mixture was stirred at 55°C for 1.5 h to ensure that the titanium silicon precursor was in full contact with the hydrophilic end of the micelle. Then, the pH of the solution was adjusted to 8.5 with 10 mol / L hydrochloric acid to promote the hydrolysis of silicon and titanium sources on the surface of the template agent micelle to generate silicic acid and titanium acid. The mixture was then heated to 90°C and aged for 4 h to obtain a milky white suspension.

[0086] S3, the above milky white suspension was filtered to obtain a white solid and washed several times with deionized water until the sample was neutral. The sample was then dried in an oven at 80°C overnight to obtain the precursor material.

[0087] S4. The precursor material was treated with argon plasma for 50 min at a power of 40 W. The sample was then reduced in a 20% hydrogen-argon mixture at a rate of 5 °C / min to 400 °C for 2 h. After reduction, it was allowed to cool naturally to room temperature. This yielded an ordered mesoporous titanium-silicon material with internal modification to nitrogen-carbon material and containing trivalent titanium. The nitrogen-carbon material accounted for 12% of the mass of the support, and the trivalent titanium accounted for 4.0% of the total titanium in the support. The average pore size of the support was 4.5 nm, and the specific surface area was 680 m². 2 / g;

[0088] S5, add 5% (by total metal weight) of palladium nitrate (internal modification of nitrogen-carbon material and containing trivalent titanium) of ordered mesoporous titanium-silicon material to a beaker and disperse and dissolve it in 200 mL of 0.1 M hydrochloric acid aqueous solution. Then add the internal modification of nitrogen-carbon material and containing trivalent titanium and disperse it ultrasonically for 2 h. Then evaporate the solvent at 80 °C to remove it. The dried solid is calcined in argon at 10 °C / min to 450 °C for 4 h to obtain the catalyst powder.

[0089] S6. The catalyst powder was compressed, crushed, and sieved through a 20-40 mesh to obtain catalyst particles. 20g of the catalyst was loaded into a fixed-bed reactor, and hydrogen was introduced to reduce and activate it at 200℃ for 2h. When the temperature of the reaction bed dropped to 80℃ and the H2 pressure rose to 0.5MPa, a tetramethylpiperidone solution (ethanol:tetramethylpiperidone = 10:1, mass ratio) was introduced at a feed rate of 2.0g / min, and hydrogen was introduced at a flow rate of 15ml / min. The reaction products were detected by gas chromatography.

[0090] Example 6

[0091] The difference from Example 1 is that, in S1, 0.1 mol of hexadecyltrimethylammonium bromide (CTAB) was dissolved in 1 L of deionized water and stirred at 40 °C for 2 h, and the surfactant self-assembled to form a low-concentration micelle solution with a concentration of 0.1 mol / L.

[0092] S2, a mixed aqueous solution containing 1 mol sodium metasilicate and 0.1 mol titanium oxysulfate was slowly added dropwise to the above micelle solution, and the mixture was stirred at 40°C for 1 h to ensure that the titanium silicon precursor was in full contact with the hydrophilic end of the micelle. Then, the pH of the solution was adjusted to 7 with 12 mol / L hydrochloric acid to promote the hydrolysis of silicon source and titanium source on the surface of template agent micelle to generate silicic acid and titanium acid. The mixture was then heated to 80°C and aged for 6 h to obtain a milky white suspension.

[0093] S3, the above milky white suspension was filtered to obtain a white solid and washed several times with deionized water until the sample was neutral. The sample was then dried in an oven at 90°C overnight to obtain the precursor material.

[0094] S4. The precursor material was treated with argon plasma for 60 min at a power of 10 W. The sample was then reduced in a 10% hydrogen-argon mixture at a temperature increased to 350 °C at a rate of 10 °C / min for 3 h. After reduction, the sample was allowed to cool naturally to room temperature. This yielded an ordered mesoporous titanium-silicon material with internal modification to nitrogen-carbon material and containing trivalent titanium. The nitrogen-carbon material accounted for 8.5% of the mass of the support, and the trivalent titanium accounted for 4.3% of the total titanium in the support. The average pore size of the support was 6.1 nm, and the specific surface area was 600 m². 2 / g;

[0095] S5, add 5% (by total metal weight) of ruthenium acetate (based on total metal content) of ordered mesoporous titanium-silicon material with internal modification of nitrogen-carbon material and containing trivalent titanium to a beaker and disperse and dissolve it in 200 mL of deionized water. Then add the ordered mesoporous titanium-silicon material with internal modification of nitrogen-carbon material and containing trivalent titanium and ultrasonically disperse it for 2 h. Then evaporate the solvent at 80 °C to remove it. The dried solid is calcined in argon at 8 °C / min to 450 °C for 2 h to obtain the catalyst powder.

[0096] S6. The catalyst powder was compressed, crushed, and sieved through a 20-40 mesh to obtain catalyst particles. 20g of the catalyst was loaded into a fixed-bed reactor, and hydrogen was introduced to reduce and activate it at 250℃ for 3h. When the temperature of the reaction bed dropped to 90℃ and the H2 pressure rose to 1MPa, a tetramethylpiperidone solution (ethanol:tetramethylpiperidone = 10:1, mass ratio) was introduced at a feed rate of 2.0g / min, and hydrogen was introduced at a flow rate of 15ml / min. The reaction products were detected by gas chromatography.

[0097] Example 7

[0098] The difference from Example 1 is that, in S1, 0.05 mol of cetyltrimethylammonium bromide (CTAB) is dissolved in 1 L of deionized water and stirred at 45 °C for 2 h, and the surfactant self-assembles to form a low-concentration micelle solution with a concentration of 0.05 mol / L.

[0099] S2, a mixed aqueous solution containing 1 mol sodium metasilicate and 0.4 mol titanium oxysulfate was slowly added dropwise to the above micelle solution, and the mixture was stirred at 45°C for 2 hours to ensure that the titanium silicon precursor was in full contact with the hydrophilic end of the micelle. Then, the pH of the solution was adjusted to 7.5 with 10 mol / L hydrochloric acid to promote the hydrolysis of silicon and titanium sources on the surface of the template agent micelles to generate silicic acid and titanium acid. The mixture was then heated to 85°C and aged for 4 hours to obtain a milky white suspension.

[0100] S3, the above milky white suspension was filtered to obtain a white solid and washed several times with deionized water until the sample was neutral. The sample was then placed in an oven at 70°C and dried overnight to obtain the precursor material.

[0101] S4. The precursor material was treated with argon plasma for 30 min at a power of 20 W. The sample was then reduced in a 20% hydrogen-argon mixture at a temperature increased to 400 °C at a rate of 10 °C / min for 4 h. After reduction, the sample was allowed to cool naturally to room temperature. This yielded an ordered mesoporous titanium-silicon material with internal modification to nitrogen-carbon material and containing trivalent titanium. The nitrogen-carbon material accounted for 5.0% of the mass of the support, and the trivalent titanium accounted for 4.5% of the total titanium in the support. The average pore size of the support was 6.7 nm, and the specific surface area was 560 m². 2 / g;

[0102] S5. Platinum nitrate, weighing 3% (by total metal content) of ordered mesoporous titanium-silicon material with internal modification of nitrogen-carbon material and containing trivalent titanium, was added to a beaker and dispersed and dissolved in 200 mL of deionized water. Then, ordered mesoporous titanium-silicon material with internal modification of nitrogen-carbon material and containing trivalent titanium was added and ultrasonically dispersed for 1.5 h. The solvent was then removed by evaporation at 80 °C. The dried solid was calcined in argon at a temperature of 10 °C / min to 300 °C for 2 h to obtain the catalyst powder.

[0103] S6. The catalyst powder was compressed, crushed, and sieved through a 20-40 mesh to obtain catalyst particles. 20g of the catalyst was loaded into a fixed-bed reactor, and hydrogen was introduced to reduce and activate it at 200℃ for 1h. When the temperature of the reaction bed dropped to 80℃ and the H2 pressure rose to 0.5MPa, a tetramethylpiperidone solution (ethanol:tetramethylpiperidone = 10:1, mass ratio) was introduced at a feed rate of 2.0g / min, and hydrogen was introduced at a flow rate of 15ml / min. The reaction products were detected by gas chromatography.

[0104] Example 8

[0105] The difference from Example 1 is that, in S1, 0.15 mol of hexadecyltrimethylammonium bromide (CTAB) was dissolved in 1 L of deionized water and stirred at 55 °C for 2 h, and the surfactant self-assembled to form a low-concentration micelle solution with a concentration of 0.15 mol / L.

[0106] S2, a mixed aqueous solution containing 1 mol sodium metasilicate and 0.25 mol titanium oxysulfate was slowly added dropwise to the above micelle solution, and the mixture was stirred at 55°C for 1 h to ensure that the titanium silicon precursor was in full contact with the hydrophilic end of the micelle. Then, the pH of the solution was adjusted to 7 with 6 mol / L hydrochloric acid to promote the hydrolysis of silicon source and titanium source on the surface of template agent micelle to generate silicic acid and titanium acid. The mixture was then heated to 80°C and aged for 4 h to obtain a milky white suspension.

[0107] S3, the above milky white suspension was filtered to obtain a white solid and washed several times with deionized water until the sample was neutral. The sample was then dried in an oven at 100°C overnight to obtain the precursor material.

[0108] S4. The precursor material was treated with argon plasma for 20 min at a power of 80 W. The sample was then reduced in a 25% hydrogen-argon mixture at a rate of 5 °C / min to 350 °C for 6 h. After reduction, it was allowed to cool naturally to room temperature. This yielded an ordered mesoporous titanium-silicon material with internal modification to nitrogen-carbon material and containing trivalent titanium. This material served as a support, with a nitrogen-carbon material mass percentage of 9.3% and trivalent titanium a molar percentage of 4.2% in the total titanium content. The average pore size of the support was 5.6 nm, and its specific surface area was 635 m². 2 / g;

[0109] S5. Add 15% (by weight, based on total metal content) of a mixture of palladium nitrate, platinum nitrate, ruthenium nitrate, cobalt nitrate, nickel nitrate, copper nitrate, and chromium nitrate (internal modified with nitrogen-carbon material and containing trivalent titanium) to a beaker and disperse and dissolve it in 200 mL of 0.1 M hydrochloric acid aqueous solution. Then add the internal modified with nitrogen-carbon material and containing trivalent titanium and disperse ultrasonically for 2 h. Then evaporate the solvent at 80 °C to remove the solvent. Calcine the dried solid in argon at 350 °C for 4 h at a rate of 5 °C / min to obtain the catalyst powder.

[0110] S6. The catalyst powder was compressed, crushed, and sieved through a 20-40 mesh to obtain catalyst particles. 20g of the catalyst was loaded into a fixed-bed reactor, and hydrogen was introduced to reduce and activate it at 400℃ for 4h. When the temperature of the reaction bed dropped to 90℃ and the H2 pressure rose to 1.5MPa, a tetramethylpiperidone solution (ethanol:tetramethylpiperidone = 10:1, mass ratio) was introduced at a feed rate of 2.0g / min, and hydrogen was introduced at a flow rate of 15ml / min. The reaction products were detected by gas chromatography.

[0111] Example 9

[0112] The difference from Example 1 is that the amount of titanium oxysulfate is 0.05 mol, and the final catalyst powder is obtained. The molar ratio of silicon to titanium in the support is 1:0.05.

[0113] The catalyst powder was compressed, crushed, and sieved through a 20-40 mesh to obtain catalyst particles. 20g of the catalyst was loaded into a fixed-bed reactor, and hydrogen was introduced to reduce and activate it at 500℃ for 1h. After the temperature of the reaction bed dropped to 100℃ and the H2 pressure rose to 1MPa, a tetramethylpiperidone solution (ethanol:tetramethylpiperidone = 10:1, mass ratio) was introduced at a feed rate of 2.0g / min, and hydrogen was introduced at a flow rate of 15ml / min. The reaction products were detected by gas chromatography.

[0114] Example 10

[0115] The difference from Example 1 is that the amount of titanium oxysulfate is 0.04 mol, and the final catalyst powder is obtained. The molar ratio of silicon to titanium in the support is 1:0.04.

[0116] The catalyst powder was compressed, crushed, and sieved through a 20-40 mesh to obtain catalyst particles. 20g of the catalyst was loaded into a fixed-bed reactor, and hydrogen was introduced to reduce and activate it at 500℃ for 1h. After the temperature of the reaction bed dropped to 100℃ and the H2 pressure rose to 1MPa, a tetramethylpiperidone solution (ethanol:tetramethylpiperidone = 10:1, mass ratio) was introduced at a feed rate of 2.0g / min, and hydrogen was introduced at a flow rate of 15ml / min. The reaction products were detected by gas chromatography.

[0117] Example 11

[0118] The difference from Example 1 is that the plasma treatment power was 110W and the plasma treatment time was 70min, resulting in catalyst powder with a nitrogen-carbon material mass ratio of 2.5% in the support.

[0119] The catalyst powder was compressed, crushed, and sieved through a 20-40 mesh to obtain catalyst particles. 20g of the catalyst was loaded into a fixed-bed reactor, and hydrogen was introduced to reduce and activate it at 500℃ for 1h. After the temperature of the reaction bed dropped to 100℃ and the H2 pressure rose to 1MPa, a tetramethylpiperidone solution (ethanol:tetramethylpiperidone = 10:1, mass ratio) was introduced at a feed rate of 2.0g / min, and hydrogen was introduced at a flow rate of 15ml / min. The reaction products were detected by gas chromatography.

[0120] Example 12

[0121] The difference from Example 1 is that the reduction treatment in step S4 is carried out at a temperature of 240°C for 1 hour, and the final catalyst powder is obtained, with trivalent titanium accounting for 0.3% of the total titanium in the support.

[0122] The catalyst powder was compressed, crushed, and sieved through a 20-40 mesh to obtain catalyst particles. 20g of the catalyst was loaded into a fixed-bed reactor, and hydrogen was introduced to reduce and activate it at 500℃ for 1h. After the temperature of the reaction bed dropped to 100℃ and the H2 pressure rose to 1MPa, a tetramethylpiperidone solution (ethanol:tetramethylpiperidone = 10:1, mass ratio) was introduced at a feed rate of 2.0g / min, and hydrogen was introduced at a flow rate of 15ml / min. The reaction products were detected by gas chromatography.

[0123] Example 13

[0124] The difference from Example 1 is that the amount of hexadecyltrimethylammonium bromide is 0.25 mol, and the hexadecyltrimethylammonium bromide self-assembles to form a micelle solution with a concentration of 0.25 mol / L, ultimately yielding catalyst powder. The average pore size of the support is 3.9 nm, and the specific surface area of ​​the support is 710 m². 2 / g;

[0125] The catalyst powder was compressed, crushed, and sieved through a 20-40 mesh to obtain catalyst particles. 20g of the catalyst was loaded into a fixed-bed reactor, and hydrogen was introduced to reduce and activate it at 500℃ for 1h. After the temperature of the reaction bed dropped to 100℃ and the H2 pressure rose to 1MPa, a tetramethylpiperidone solution (ethanol:tetramethylpiperidone = 10:1, mass ratio) was introduced at a feed rate of 2.0g / min, and hydrogen was introduced at a flow rate of 15ml / min. The reaction products were detected by gas chromatography.

[0126] Comparative Example 1

[0127] The difference from Example 1 is that, in S1, 0.05 mol of hexadecyltrimethylammonium bromide (CTAB) is dissolved in 1 L of deionized water and stirred at 45 °C for 1 h, and the surfactant self-assembles to form a low-concentration micelle solution with a concentration of 0.05 mol / L.

[0128] S2, an aqueous solution containing 1 mol sodium metasilicate is slowly added dropwise to the above micelle solution, and the mixture is stirred at 45°C for 1.5 h to ensure that the silicon source and the hydrophilic end of the micelle are in full contact. Then, the pH of the solution is adjusted to 8 with 5 mol / L hydrochloric acid to promote the hydrolysis of the silicon source on the surface of the template agent micelle to generate silicic acid, and the temperature is raised to 80°C for aging for 6 h.

[0129] S3, the above milky white suspension was filtered to obtain a white solid and washed several times with deionized water until the sample was neutral. It was then placed in an oven at 90°C and dried overnight to obtain the ordered mesoporous silicon nanomaterial precursor.

[0130] S4. The ordered mesoporous silicon nanomaterial precursor was treated with argon plasma for 30 min at a power of 60 W. Then, the sample was calcined in a 10% hydrogen-argon mixture at a temperature of 5 °C / min to 400 °C for 4 h. After calcination, it was naturally cooled to room temperature. The resulting powder sample is the ordered mesoporous silicon nanomaterial modified inside the nitrogen-carbon material.

[0131] S5. Add 10% (by weight of total metal) of ordered mesoporous silica nanomaterials to a beaker and disperse and dissolve it in 200 mL of deionized water. Then add the ordered mesoporous silica nanomaterials and ultrasonically disperse for 1 h. Then evaporate the solvent at 80 °C. Calcine the dried solid at 300 °C for 4 h in argon at a rate of 5 °C / min to obtain the catalyst powder.

[0132] S6. The catalyst powder was compressed, crushed, and sieved through a 20-40 mesh to obtain catalyst particles. 20g of the catalyst was loaded into a fixed-bed reactor, and hydrogen was introduced to reduce and activate it at 500℃ for 1h. When the temperature of the reaction bed dropped to 100℃ and the H2 pressure rose to 1MPa, a tetramethylpiperidone solution (ethanol:tetramethylpiperidone = 10:1, mass ratio) was introduced at a feed rate of 2.0g / min, and hydrogen was introduced at a flow rate of 15ml / min. The reaction products were detected by gas chromatography.

[0133] Comparative Example 2

[0134] The difference from Example 1 is that, in S1, 0.05 mol of hexadecyltrimethylammonium bromide (CTAB) is dissolved in 1 L of deionized water and stirred at 45 °C for 1 h, and the surfactant self-assembles to form a low-concentration micelle solution with a concentration of 0.05 mol / L.

[0135] S2, a mixed aqueous solution containing 1 mol sodium metasilicate and 0.15 mol titanium oxysulfate was slowly added dropwise to the above micelle solution, and the mixture was stirred at 45°C for 1.5 h to ensure that the titanium silicon precursor was in full contact with the hydrophilic end of the micelle. Then, the pH of the solution was adjusted to 8 with 5 mol / L hydrochloric acid to promote the hydrolysis of silicon source and titanium source on the surface of template agent micelle to generate silicic acid and titanium acid, and the temperature was raised to 80°C for aging for 6 h.

[0136] S3, the above milky white suspension was filtered to obtain a white solid and washed several times with deionized water until the sample was neutral. It was then placed in an oven at 90°C and dried overnight to obtain the ordered mesoporous titanium-silicon nanomaterial precursor.

[0137] S4. The ordered mesoporous titanium-silicon nanomaterial precursor was calcined in air at 550°C for 4 hours to completely remove the cationic surfactant template. Then, the sample was calcined in a 10% hydrogen-argon mixture at 5°C / min to 400°C for 4 hours. After calcination, it was naturally cooled to room temperature. The resulting powder sample is the ordered mesoporous titanium-silicon nanomaterial rich in defect-state titanium species.

[0138] S5. Add 10% (by weight of total metal) of ordered mesoporous titanium-silicon nanomaterials in nickel nitrate to a beaker and disperse and dissolve it in 200 mL of deionized water. Then add the ordered mesoporous titanium-silicon nanomaterials and ultrasonically disperse for 1 h. Then evaporate the solvent at 80 °C to remove the solvent. The dried solid is calcined in argon at 300 °C for 4 h at a rate of 5 °C / min to obtain the catalyst powder.

[0139] S6. The catalyst powder was compressed, crushed, and sieved through a 20-40 mesh to obtain catalyst particles. 20g of the catalyst was loaded into a fixed-bed reactor, and hydrogen was introduced to reduce and activate it at 500℃ for 1h. When the temperature of the reaction bed dropped to 100℃ and the H2 pressure rose to 1MPa, a tetramethylpiperidone solution (ethanol:tetramethylpiperidone = 10:1, mass ratio) was introduced at a feed rate of 2.0g / min, and hydrogen was introduced at a flow rate of 15ml / min. The reaction products were detected by gas chromatography.

[0140] Comparative Example 3

[0141] The difference from Example 1 is that, in S1, 0.05 mol of hexadecyltrimethylammonium bromide (CTAB) is dissolved in 1 L of deionized water and stirred at 45 °C for 1 h, and the surfactant self-assembles to form a low-concentration micelle solution with a concentration of 0.05 mol / L.

[0142] S2, an aqueous solution containing 1 mol sodium metasilicate is slowly added dropwise to the above micelle solution, and the mixture is stirred at 45°C for 1.5 h to ensure that the silicon source and the hydrophilic end of the micelle are in full contact. Then, the pH of the solution is adjusted to 8 with 5 mol / L hydrochloric acid to promote the hydrolysis of the silicon source on the surface of the template agent micelle to generate silicic acid, and the temperature is raised to 80°C for aging for 6 h.

[0143] S3, the above milky white suspension was filtered to obtain a white solid and washed several times with deionized water until the sample was neutral. It was then placed in an oven at 90°C and dried overnight to obtain the ordered mesoporous silicon nanomaterial precursor.

[0144] S4. The ordered mesoporous silicon nanomaterial precursor was calcined in air at 550°C for 4 hours to completely remove the cationic surfactant template. Then, the sample was calcined in a 10% hydrogen-argon mixture at 5°C / min to 400°C for 4 hours. After calcination, it was naturally cooled to room temperature. The resulting powder sample is the ordered mesoporous silicon nanomaterial.

[0145] S5. Add 10% (by weight of total metal) of ordered mesoporous silica nanomaterials to a beaker and disperse and dissolve it in 200 mL of deionized water. Then add the ordered mesoporous silica nanomaterials and ultrasonically disperse for 1 h. Then evaporate the solvent at 80 °C. Calcine the dried solid at 300 °C for 4 h in argon at a rate of 5 °C / min to obtain the catalyst powder.

[0146] S6. The catalyst powder was compressed, crushed, and sieved through a 20-40 mesh to obtain catalyst particles. 20g of the catalyst was loaded into a fixed-bed reactor, and hydrogen was introduced to reduce and activate it at 500℃ for 1h. When the temperature of the reaction bed dropped to 100℃ and the H2 pressure rose to 1MPa, a tetramethylpiperidone solution (ethanol:tetramethylpiperidone = 10:1, mass ratio) was introduced at a feed rate of 2.0g / min, and hydrogen was introduced at a flow rate of 15ml / min. The reaction products were detected by gas chromatography.

[0147] Comparative Example 4

[0148] The difference from Example 1 is that the 10% hydrogen-argon mixture in the reduction process in step S4 is replaced with argon gas, and the catalyst powder is finally obtained.

[0149] The catalyst powder was compressed, crushed, and sieved through a 20-40 mesh to obtain catalyst particles. 20g of the catalyst was loaded into a fixed-bed reactor, and hydrogen was introduced to reduce and activate it at 500℃ for 1h. After the temperature of the reaction bed dropped to 100℃ and the H2 pressure rose to 1MPa, a tetramethylpiperidone solution (ethanol:tetramethylpiperidone = 10:1, mass ratio) was introduced at a feed rate of 2.0g / min, and hydrogen was introduced at a flow rate of 15ml / min. The reaction products were detected by gas chromatography.

[0150] The conversion rate of tetramethylpiperidone and the selectivity for generating 2,2,6,6-tetramethyl-4-piperidinol were calculated based on the gas chromatography detection results in the examples and comparative examples. The results are shown in Table 1.

[0151] Table 1

[0152]

[0153] Figure 1 This is a TEM image of the carrier in Embodiment 1 of this application. As can be seen from the image, the carrier has a uniform and ordered mesoporous structure with a pore size of about 5.8 nm and a channel length of 150~200 nm.

[0154] Figure 2 The gas chromatogram of 2,2,6,6-tetramethyl-4-piperidinol in Example 1 of this application shows that the retention times at 4.209 min and 5.825 min are mixed solvent peaks, 15.489 min is an impurity peak, and 17.556 min is the chromatographic peak of 2,2,6,6-tetramethyl-4-piperidinol. Figure 2 It can be seen that 2,2,6,6-tetramethyl-4-piperidinol has high purity.

[0155] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0156] The catalyst in this application utilizes an ordered mesoporous titanium-silicon material internally modified with nitrogen-carbon material and containing trivalent titanium. Nitrogen in the nitrogen-carbon material provides lone pairs of electrons, acting as Lewis basic sites, while trivalent titanium is electron-deficient, acting as Lewis acidic centers. These two elements form a hindered Lewis acid-base pair within the confined space of the ordered mesoporous structure. This hindered Lewis acid-base pair facilitates the anchoring of the transition metal active component and promotes the adsorption and activation of the substrate tetramethylpiperidone, thereby enhancing the reaction kinetics of the catalytic hydrogenation process. Surface defects formed by trivalent titanium induce strong metal-support interactions between the transition metal and the mesoporous pore walls, improving the dispersion and stability of the transition metal within the mesoporous channels, exposing more reactive sites, and thus enhancing the catalyst's activity and selectivity. The confined space created by the ordered mesoporous structure inhibits the aggregation of the transition metal during the catalytic reaction, contributing to a longer catalyst lifespan. Furthermore, the nitrogen-carbon material on the mesoporous pore walls generates numerous transition metal-nitrogen-carbon interfaces with the active transition metal, lowering the hydrogen dissociation barrier and further improving the conversion efficiency of tetramethylpiperidone. Therefore, the catalyst of this application has high selectivity in the catalytic hydrogenation of tetramethylpiperidone to 2,2,6,6-tetramethyl-4-piperidinol, which helps to improve the yield of 2,2,6,6-tetramethyl-4-piperidinol.

[0157] The above are merely embodiments of the present invention and are not intended to limit the invention. Those skilled in the art will recognize that the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A catalyst, characterized in that, The catalyst includes a support and a transition metal supported on the support, wherein the support is an ordered mesoporous titanium-silicon material internally modified with nitrogen-carbon material and containing trivalent titanium. The method for preparing the catalyst includes: Step S1: The aqueous solution containing silicon source and titanium source is mixed with the aqueous solution containing surfactant, and then pH adjustment, aging treatment and solid-liquid separation are performed in sequence to obtain the precursor material. Step S2: The precursor material is subjected to plasma treatment to form a nitrogen-carbon material and reduction treatment to form trivalent titanium in sequence, so as to obtain an ordered mesoporous titanium-silicon material with internal modification of the nitrogen-carbon material and containing trivalent titanium. Step S3: The ordered mesoporous titanium-silicon material with internal modification of the nitrogen-carbon material and containing trivalent titanium, the transition metal source and water are mixed and then subjected to drying and calcination treatment in sequence to obtain the catalyst; In step S2, the power of the plasma treatment is 10~100W, and the plasma treatment time is 10~60min; The reduction treatment temperature is 250~450℃, the reduction treatment time is 2~6h, and the heating rate of the reduction treatment is 5~15℃ / min; The silicon source is selected from sodium metasilicate and / or sodium silicate; the titanium source is selected from any one or more of titanium sulfate, titanium oxysulfate, and titanium nitrate; the surfactant has the general formula [NR]. 1 R 2 R 3 R 4 X, where R 1 C 12 ~C 20 straight-chain alkyl, R 2 R 3 and R 4 Each is an alkyl group of C1 to C4, and X is a halogen atom; the transition metal source is selected from any one or more of Pd source, Pt source, Ru source, Co source, Ni source, Cu source and Cr source; The mass percentage of the nitrogen-carbon material in the carrier is 3.0~15.0%; the molar percentage of the trivalent titanium in the total titanium in the carrier is 0.5~5.0%; the loading of the transition metal is 3~20% of the mass of the carrier; and the molar ratio of silicon to titanium in the carrier is 1:(0.05~0.5).

2. The catalyst according to claim 1, characterized in that, The average pore size of the carrier is 4.0~7.0 nm; and / or, the specific surface area of ​​the carrier is 500~700 m². 2 / g; and / or, the particle size of the catalyst is 20~40 mesh.

3. A method for preparing the catalyst according to claim 1 or 2, characterized in that, The preparation method includes: Step S1: The aqueous solution containing silicon source and titanium source is mixed with the aqueous solution containing surfactant, and then pH adjustment, aging treatment and solid-liquid separation are performed in sequence to obtain the precursor material. Step S2: The precursor material is subjected to plasma treatment to form a nitrogen-carbon material and reduction treatment to form trivalent titanium in sequence, so as to obtain an ordered mesoporous titanium-silicon material with internal modification of the nitrogen-carbon material and containing trivalent titanium. Step S3: The ordered mesoporous titanium-silicon material with internal modification of the nitrogen-carbon material and containing trivalent titanium, the transition metal source and water are mixed and then dried and calcined in sequence to obtain the catalyst; In step S2, the power of the plasma treatment is 10~100W, and the plasma treatment time is 10~60min; The reduction treatment temperature is 250~450℃, the reduction treatment time is 2~6h, and the heating rate of the reduction treatment is 5~15℃ / min; The silicon source is selected from sodium metasilicate and / or sodium silicate; the titanium source is selected from any one or more of titanium sulfate, titanium oxysulfate, and titanium nitrate; the surfactant has the general formula [NR]. 1 R 2 R 3 R 4 X, where R 1 C 12 ~C 20 straight-chain alkyl, R 2 R 3 and R 4 Each is an alkyl group of C1 to C4, and X is a halogen atom; the transition metal source is selected from any one or more of Pd source, Pt source, Ru source, Co source, Ni source, Cu source and Cr source.

4. The method for preparing the catalyst according to claim 3, characterized in that, In step S1, the molar ratio of the silicon source, the titanium source, and the surfactant is 1:(0.05~0.5):(0.01~0.2). And / or, the micelle concentration in the aqueous solution containing the surfactant is 0.01~0.2 mol / L; and / or, the pH value of the solution after pH adjustment is 7~9; And / or, the aging treatment temperature is 60~100℃, and the aging treatment time is 4~8h.

5. The method for preparing the catalyst according to claim 3 or 4, characterized in that, In step S3, the calcination temperature is 300~500℃, the calcination time is 2~4h, and the heating rate of the calcination is 5~15℃ / min.

6. A method for preparing 2,2,6,6-tetramethyl-4-piperidinol, characterized in that, The preparation method includes: loading the catalyst according to claim 1 or 2 into a continuous fixed-bed reactor, and introducing tetramethylpiperidone and hydrogen to carry out a hydrogenation catalytic reaction to obtain the 2,2,6,6-tetramethyl-4-piperidinol.

7. The method for preparing 2,2,6,6-tetramethyl-4-piperidinol according to claim 6, characterized in that, The preparation method further includes: activating the catalyst before carrying out the hydrogenation catalytic reaction, wherein the activation temperature is 200~500℃ and the activation time is 1~5h.

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