Supported nitrogen-containing ligand-ruthenium-based catalyst, preparation method and application

Abstract

The invention relates to the technical field of catalyst preparation, in particular to a supported nitrogen-containing ligand-ruthenium-based catalyst, a preparation method and application, and provides guarantee for anchoring and high dispersion of an active substance ruthenium on activated carbon by utilizing interaction force between an N-substituted imidazole compound and metal ruthenium. Due to electron transfer, a Ru-N bond is formed, a low-valence ruthenium active species is stabilized, and the adsorption capacity of the catalyst to a reactant 1-hexene is improved, so that the activity of the catalyst is remarkably improved. The N-substituted imidazole compound enables ruthenium species to be deposited on activated carbon, and loss of precious metal ruthenium is reduced. Compared with heterogeneous catalysts prepared from other noble metals, the catalyst has the characteristics of low cost and good activity, and has better economic value. The problem that the Ru-based heterogeneous catalyst is inactivated due to high-temperature agglomeration or leaching loss in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of catalyst preparation, and in particular to a supported nitrogen-containing ligand-ruthenium-based catalyst, a preparation method and an application thereof. Background Art

[0002] Organosilicon, or organic silicon compounds, refers to compounds containing Si-C bonds and at least one organic group directly attached to a silicon atom. Compounds in which organic groups are linked to silicon atoms through oxygen, sulfur, nitrogen, or other molecules are also commonly considered organosilicon compounds. Organosilicon materials possess a unique structure, such as abundant methyl groups on the Si atoms shielding the high-energy polysiloxane backbone, long Si-O bond lengths and large bond angles, and covalent bonds with 50% ionic characteristics. These structural characteristics enable organosilicon to combine the properties of both inorganic and organic materials, exhibiting fundamental properties such as low surface tension, low viscosity-temperature coefficient, high compressibility, and high gas permeability. They are a class of high-performance chemical materials with diverse forms, a wide variety, excellent performance, and a wide range of applications. Organosilicon compounds and the materials derived from them have found widespread application in organic synthesis, pharmaceutical engineering, aerospace, semiconductor chips, national defense, and everyday life, becoming indispensable chemical materials for modern industry. Organosilicon products can be broadly divided into four categories: silicone oil, silicone rubber, silicone resin, and silane coupling agents. The first three are collectively referred to as polyorganosiloxanes. The corresponding products are used in large quantities and possess many unique properties, including high and low temperature resistance, weather resistance, adhesion and sealing, electrical insulation, and physiological inertness. Among them, n-hexyltriethoxysilane possesses the typical structure and properties of organosilicon compounds and is commonly used for engineering plastic modification, building waterproofing and corrosion prevention, rubber and plastic mold release, and glass anti-fogging. It can also be used as a silane coupling agent. Through its unique reactivity, it can improve the interfacial bonding between inorganic and organic materials, thereby enhancing the performance of composite materials. Furthermore, it can be used as a surfactant and waterproofing agent, playing an important role in various industrial fields. The preparation of n-hexyltriethoxysilane typically involves the addition reaction of silanes with olefins, known as the olefin hydrosilylation reaction. The silane provides the silicon-hydrogen bond, while the olefin provides the carbon chain. Under the action of a catalyst, the silicon-hydrogen bond reacts with the double bond of the olefin to produce the target product, n-hexyltriethoxysilane.

[0003] The catalytic system for olefin hydrosilylation reactions is generally carried out using homogeneous or heterogeneous catalysis. Although homogeneous catalysis is more active than heterogeneous catalysis, it has the disadvantages of low target product selectivity, the susceptibility of homogeneous catalysts to corrosion of metal containers, difficulty in separation and recovery in the catalytic system, and waste of precious metal catalysts. Therefore, the choice of preparing heterogeneous catalysts would be a good breakthrough. To improve catalyst stability, catalytic activity, and selectivity, olefin hydrosilylation reaction catalysts are currently mainly prepared using precious metals such as Rh, Pt, and Ir. However, these metals are expensive and have high costs, resulting in low economic benefits in practical applications. Compared with the above metals, Ru is much cheaper than other platinum group metals due to its low mining and processing costs. Currently, there are few reports on heterogeneous catalysts for olefin hydrosilylation reactions using Ru as the active component, and no reports have been found on its use as a component of heterogeneous catalysts. This is because the preparation of heterogeneous catalysts using Ru has always faced the problem of catalyst deactivation due to high-temperature agglomeration or leaching loss, which has hindered its research and development. Therefore, developing a new catalytic system is the key to solving this problem. Summary of the Invention

[0004] In view of the problem in the prior art that Ru-based heterogeneous catalysts are deactivated due to high-temperature agglomeration or leaching loss, the present invention provides a supported nitrogen-containing ligand-ruthenium-based catalyst, a preparation method and application.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention provides a supported nitrogen-containing ligand-ruthenium-based catalyst, the raw material components of which include a carrier, a ligand and a stable metal precursor; the stable metal precursor is a ruthenium salt, the carrier is activated carbon, and the ligand is an N-substituted imidazole compound; the molar ratio of the stable metal precursor to the ligand is (4:1) to (1:2), and the mass of ruthenium in the stable metal precursor is 0.6% to 1.2% of the mass of the carrier.

[0006] Optionally, the stable metal precursor is RuCl3.

[0007] Optionally, the ligand is N-methylimidazole or N-allylimidazole.

[0008] Optionally, the carrier is wood activated carbon.

[0009] Optionally, the carrier is coconut shell activated carbon.

[0010] Optionally, the molar ratio of the stable metal precursor to the ligand is 2:1.

[0011] The present invention provides a method for preparing the above-mentioned supported nitrogen-containing ligand-ruthenium-based catalyst, comprising: The ligand, the stable metal precursor and the support are mixed in anhydrous ethanol to form a mixed solution; The mixed solution is heated in a constant temperature water bath, filtered, washed and dried to obtain a supported nitrogen-containing ligand-ruthenium-based catalyst.

[0012] Optionally, the constant temperature water bath is heated at a temperature of 70° C. to 100° C., and the heating time is 6 to 8 hours.

[0013] Optionally, the drying condition is vacuum drying at 60°C to 80°C.

[0014] Application of the above-mentioned supported nitrogen-containing ligand-ruthenium-based catalyst in the catalytic preparation of n-hexyltriethoxysilane.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a supported nitrogen-containing ligand-ruthenium-based catalyst, whose raw material components include a support, a ligand, and a stable metal precursor. The catalyst uses activated carbon as the support, a ruthenium salt as the stable metal precursor, and an N-substituted imidazole compound as the ligand. The interaction between the ruthenium metal and the N-substituted imidazole compound ensures the anchoring and high dispersion of the active ruthenium on the activated carbon, preventing catalyst deactivation due to agglomeration. Furthermore, electron transfer between the N-substituted imidazole compound and the metal precursor forms a Ru-N bond, stabilizing the low-valent ruthenium active species and further enhancing the catalyst's adsorption capacity for the reactant 1-hexene, thereby significantly improving the catalyst's activity. Furthermore, the addition of the N-substituted imidazole compound allows the ruthenium species to be deposited on the activated carbon, thereby reducing the loss of precious ruthenium during the catalyst preparation process and preventing the loss of ruthenium that can reduce catalyst activity. Compared to other heterogeneous catalysts prepared from precious metals, this catalyst offers low cost, high activity, and better economic value.

[0016] The activated carbon is preferably coconut shell activated carbon among wood activated carbons, which has a wide source of materials, is simple to prepare, has low cost, and has good effects.

[0017] The present invention also provides a method for preparing the above-mentioned supported nitrogen-containing ligand-ruthenium-based catalyst. This method comprises mixing the ligand, a stable metal precursor, and a support in anhydrous ethanol, heating in a constant-temperature water bath, filtering, washing, and drying to obtain the supported nitrogen-containing ligand-ruthenium-based catalyst. The preparation method is simple, does not require special supporting expensive equipment, and has mild reaction conditions, is pollution-free, and is low-cost, making it suitable for industrialization.

[0018] The present invention also provides the use of the above-mentioned supported nitrogen-containing ligand-ruthenium-based catalyst in the catalytic preparation of n-hexyltriethoxysilane. This catalyst is used in the hydrosilylation reaction of olefins to produce n-hexyltriethoxysilane. It features simple use, low cost, and high activity, and has good economic value and industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The figure is a schematic flow chart of a method for preparing a supported nitrogen-containing ligand-ruthenium-based catalyst according to the present invention.

[0020] Figure 2 The catalyst Ru-MLDZ of the present invention 2:1 / AC catalytic performance diagram, where Figure a is the relationship between 1-hexene conversion and reaction time, and Figure b is the relationship between n-hexyltriethoxysilane selectivity and reaction time.

[0021] Figure 3 The catalyst Ru-ALDZ of the present invention 2:1 / AC catalytic performance diagram, where Figure a is the relationship between 1-hexene conversion and reaction time; Figure b is the relationship between n-hexyltriethoxysilane selectivity and reaction time.

[0022] Figure 4 AC-HAADF-STEM images of the ruthenium-based catalyst of the present invention, wherein Figure a is the AC-HAADF-STEM image of Ru / AC; Figure b is the AC-HAADF-STEM image of Ru-MLDZ 2:1 AC-HAADF-STEM image of / AC; Figure c is Ru-ALDZ 2:1 AC-HAADF-STEM image of / AC.

[0023] Figure 5 Catalyst Ru-MLDZ 2:1 / AC XRD pattern.

[0024] Figure 6 Catalyst Ru-ALDZ 2:1 / AC XRD pattern.

[0025] Figure 7 Catalyst Ru-MLDZ 2:1 XPS graphs of / AC, where Figure a is the Ru 3p spectrum of Ru-N-methylimidazole / AC, and Figure b is the N 1s spectrum of Ru-N-allylimidazole / AC.

[0026] Figure 8 Catalyst Ru-ALDZ 2:1XPS graphs of / AC, where Figure a is the Ru 3p spectrum of Ru-N-methylimidazole / AC; Figure b is the N 1s spectrum of Ru-N-allylimidazole / AC. DETAILED DESCRIPTION

[0027] To facilitate understanding of the features and effects of the present invention by those skilled in the art, the following provides a general description and definition of the terms and expressions used in the specification and claims. Unless otherwise indicated, all technical and scientific terms used herein have the ordinary meanings as understood by those skilled in the art regarding the present invention. In the event of conflict, the definitions in this specification shall prevail.

[0028] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0029] All features, such as values, amounts, contents, and concentrations, described herein as numerical ranges or percentage ranges are provided for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to include and specifically disclose all possible subranges and individual values ​​within the range (including integers and fractions).

[0030] In this document, unless otherwise specified, “include,” “including,” “contains,” “has” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0031] In this document, for the sake of brevity, not all possible combinations of the various technical features in each embodiment or example are described. Therefore, as long as there are no contradictions in the combination of these technical features, the various technical features in each embodiment or example can be combined in any way, and all possible combinations should be considered to be within the scope of this specification.

[0032] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0033] The following examples were prepared using conventional instruments and equipment in the art. Experimental methods in the following examples, where specific conditions are not specified, were generally performed under conventional conditions or according to the conditions recommended by the manufacturer. The various raw materials used in the following examples, unless otherwise specified, were conventional commercially available products, with specifications conventional in the art. In the present specification and the following examples, unless otherwise specified, "%" indicates percentage by weight, "part" indicates parts by weight, and "ratio" indicates weight ratio.

[0034] The present invention will be further described in detail below with reference to specific embodiments, which are intended to explain the present invention rather than to limit it.

[0035] The present invention provides a supported nitrogen-containing ligand-ruthenium-based catalyst, the raw material components of which include a carrier, a ligand and a stable metal precursor; the stable metal precursor is a ruthenium salt, preferably RuCl3; the carrier is activated carbon, preferably wood activated carbon, more preferably coconut shell activated carbon, and the particle size of the coconut shell activated carbon is 120-140 mesh; the ligand is an N-substituted imidazole compound, preferably N-methylimidazole or N-allylimidazole; the molar ratio of the stable metal precursor to the ligand is (4:1) to (1:2), preferably (4:1) to (1:1), more preferably 2:1; the mass of ruthenium in the stable metal precursor is 0.6% to 1.2% of the mass of the carrier, preferably 0.8% to 1.2%, more preferably 0.9% to 1.1%.

[0036] See also Figure 1 The present invention provides a method for preparing the above-mentioned supported nitrogen-containing ligand-ruthenium-based catalyst, comprising: S1: Mix the ligand, the stable metal precursor and the support in anhydrous ethanol to form a mixed solution; specifically: The ligand is mixed with anhydrous ethanol to obtain a ligand solution. The stable metal precursor solution dissolved in anhydrous ethanol is then mixed with the aforementioned ligand solution and stirred for 4-6 hours. Activated carbon is then added and stirred for 12-24 hours to obtain a mixed solution. The carrier is pretreated before use. First, it is ground using a ball mill to select activated carbon powder with a mesh size of 120-140. The powder is then washed with ultrapure water and dried in an oven at 100-120°C for 12-18 hours.

[0037] S2: The mixed solution is heated in a constant temperature water bath, filtered, washed, and dried to obtain a supported nitrogen-containing ligand-ruthenium-based catalyst, specifically: The mixed solution was placed in a constant temperature water bath at 70°C to 100°C for 6 to 8 hours, washed with ultrapure water and anhydrous ethanol 3 to 4 times in sequence, and dried in a vacuum oven at 60°C to 80°C for 12 hours to obtain a supported nitrogen-containing ligand-ruthenium-based catalyst.

[0038] Example 1 In a 100mL beaker, add 0.0238g of N-methylimidazole to 20mL of anhydrous ethanol and sonicate for 5-10min. Add 7.555mL of ruthenium chloride trihydrate ethanol solution with a concentration of 0.01g / mL and sonicate for 5-10min. Stir at room temperature for 6-8h. Subsequently, add 2.8131g of coconut shell activated carbon while stirring and stir for 12-18h. Subsequently, place in a constant temperature water bath at 70℃ for 8h, filter, and wash with 400mL of ultrapure water and 100mL of anhydrous ethanol 3-4 times. Finally, dry in a vacuum oven at 60℃ for 18h to obtain a supported nitrogen-containing ligand-ruthenium-based catalyst, recorded as Ru-MLDZ. 1:1 / AC.

[0039] Example 2 In a 100mL beaker, add 0.0119g of N-methylimidazole to 20mL of anhydrous ethanol and sonicate for 5-10min. Add 7.555mL of ruthenium chloride trihydrate ethanol solution with a concentration of 0.01g / mL and sonicate for 5-10min. Stir at room temperature for 6-8h. Subsequently, add 2.8131g of coconut shell activated carbon while stirring and stir for 12-18h. Subsequently, place in a constant temperature water bath at 70℃ for 8h, filter, and wash with 400mL of ultrapure water and 100mL of anhydrous ethanol 3-4 times. Finally, dry in a vacuum oven at 60℃ for 18h to obtain a supported nitrogen-containing ligand-ruthenium-based catalyst, recorded as Ru-MLDZ. 2:1 / AC.

[0040] Example 3 In a 100mL beaker, add 0.0079g of N-methylimidazole to 20mL of anhydrous ethanol and sonicate for 5-10min. Add 7.555mL of ruthenium chloride trihydrate ethanol solution with a concentration of 0.01g / mL and sonicate for 5-10min. Stir at room temperature for 6-8h. Subsequently, add 2.8131g of coconut shell activated carbon while stirring and stir for 12-18h. Subsequently, place in a constant temperature water bath at 70℃ for 8h, filter, and wash with 400mL of ultrapure water and 100mL of anhydrous ethanol 3-4 times. Finally, dry in a vacuum oven at 60℃ for 18h to obtain a supported nitrogen-containing ligand-ruthenium-based catalyst, recorded as Ru-MLDZ. 3:1 / AC.

[0041] Example 4 In a 100mL beaker, add 0.0059g of N-methylimidazole to 20mL of anhydrous ethanol and sonicate for 5-10min. Add 7.555mL of ruthenium chloride trihydrate ethanol solution with a concentration of 0.01g / mL and sonicate for 5-10min. Stir at room temperature for 6-8h. Subsequently, add 2.8131g of coconut shell activated carbon while stirring and stir for 12-18h. Subsequently, place in a constant temperature water bath at 70℃ for 8h, filter, and wash with 400mL of ultrapure water and 100mL of anhydrous ethanol 3-4 times. Finally, dry in a vacuum oven at 60℃ for 18h to obtain a supported nitrogen-containing ligand-ruthenium-based catalyst, recorded as Ru-MLDZ. 4:1 / AC.

[0042] Example 5 In a 100mL beaker, add 0.0475g of N-methylimidazole to 20mL of anhydrous ethanol and sonicate for 5-10min. Add 7.555mL of ruthenium chloride trihydrate ethanol solution with a concentration of 0.01g / mL and sonicate for 5-10min. Stir at room temperature for 6-8h. Subsequently, add 2.8131g of coconut shell activated carbon while stirring and stir for 12-18h. Subsequently, place in a constant temperature water bath at 70℃ for 8h, filter, and wash with 400mL of ultrapure water and 100mL of anhydrous ethanol 3-4 times. Finally, dry in a vacuum oven at 60℃ for 18h to obtain a supported nitrogen-containing ligand-ruthenium-based catalyst, recorded as Ru-MLDZ. 1:2 / AC.

[0043] Example 6 In a 100mL beaker, add 0.0312g of N-allylimidazole to 20mL of anhydrous ethanol and sonicate for 5-10min. Add 7.555mL of ruthenium chloride trihydrate ethanol solution with a concentration of 0.01g / mL and sonicate for 5-10min. Then add 2.7980g of activated carbon while stirring and stir for 12-18h. Then, place in a constant temperature water bath at 70℃ for 8h, filter, and wash with 400mL of ultrapure water and 100mL of anhydrous ethanol 3-4 times. Finally, dry in a vacuum oven at 60℃ for 18h to obtain a supported nitrogen-containing ligand-ruthenium-based catalyst, Ru-ALDZ. 1:1 / AC.

[0044] Example 7 In a 100mL beaker, add 0.0156g of N-allylimidazole to 20mL of anhydrous ethanol and sonicate for 5-10min. Add 7.555mL of ruthenium chloride trihydrate ethanol solution with a concentration of 0.01g / mL and sonicate for 5-10min. Then add 2.7980g of activated carbon while stirring and stir for 12-18h. Then, place in a constant temperature water bath at 70℃ for 8h, filter, and wash with 400mL of ultrapure water and 100mL of anhydrous ethanol 3-4 times. Finally, dry in a vacuum oven at 60℃ for 18h to obtain a supported nitrogen-containing ligand-ruthenium-based catalyst, Ru-ALDZ. 2:1 / AC.

[0045] Example 8 In a 100mL beaker, add 0.0104g of N-allylimidazole to 20mL of anhydrous ethanol and sonicate for 5-10min. Add 7.555mL of ruthenium chloride trihydrate ethanol solution with a concentration of 0.01g / mL and sonicate for 5-10min. Then add 2.7980g of activated carbon while stirring and stir for 12-18h. Then, place in a constant temperature water bath at 70℃ for 8h, filter, and wash with 400mL of ultrapure water and 100mL of anhydrous ethanol 3-4 times. Finally, dry in a vacuum oven at 60℃ for 18h to obtain a supported nitrogen-containing ligand-ruthenium-based catalyst, Ru-ALDZ. 3:1 / AC.

[0046] Example 9 In a 100mL beaker, add 0.0078g of N-allylimidazole to 20mL of anhydrous ethanol and sonicate for 5-10min. Add 7.555mL of ruthenium chloride trihydrate ethanol solution with a concentration of 0.01g / mL and sonicate for 5-10min. Then add 2.7980g of activated carbon while stirring and stir for 12-18h. Then, place in a constant temperature water bath at 70℃ for 8h, filter, and wash with 400mL of ultrapure water and 100mL of anhydrous ethanol 3-4 times. Finally, dry in a vacuum oven at 60℃ for 18h to obtain a supported nitrogen-containing ligand-ruthenium-based catalyst, Ru-ALDZ. 4:1 / AC.

[0047] Example 10 In a 100mL beaker, add 0.0626g of N-allylimidazole to 20mL of anhydrous ethanol and sonicate for 5 to 10 minutes. Add 7.555mL of ruthenium chloride trihydrate ethanol solution with a concentration of 0.01g / mL and sonicate for 5 to 10 minutes. Then add 2.7980g of activated carbon while stirring and stir for 12 to 18 hours. Then, place in a constant temperature water bath at 70℃ for 8 hours, filter, and wash with 400mL of ultrapure water and 100mL of anhydrous ethanol 3 to 4 times. Finally, dry in a vacuum oven at 60℃ for 18 hours to obtain a supported nitrogen-containing ligand-ruthenium-based catalyst, Ru-ALDZ. 1:2 / AC.

[0048] Example 11 In a 100mL beaker, add 0.0156g of N-allylimidazole to 20mL of anhydrous ethanol and sonicate for 5-10 minutes. Add 7.555mL of ruthenium chloride trihydrate in ethanol at a concentration of 0.01g / mL and sonicate for 5-10 minutes. Then, add 2.7980g of activated carbon while stirring, and stir for 12-18 hours. Then, place the mixture in an 80°C waterbath for 7 hours, filter, and wash three to four times with 400mL of ultrapure water and then 100mL of anhydrous ethanol. Finally, dry in a 70°C vacuum oven for 16 hours to obtain a supported nitrogen-containing ligand-ruthenium-based catalyst.

[0049] Example 12 In a 100mL beaker, add 0.0156g of N-allylimidazole to 20mL of anhydrous ethanol and sonicate for 5-10 minutes. Add 7.555mL of ruthenium chloride trihydrate in ethanol at a concentration of 0.01g / mL and sonicate for 5-10 minutes. Then, add 2.7980g of activated carbon while stirring, and stir for 12-18 hours. Then, place the mixture in a 100°C waterbath for 6 hours, filter, and wash three to four times with 400mL of ultrapure water and then 100mL of anhydrous ethanol. Finally, dry in a vacuum oven at 80°C for 12 hours to obtain a supported nitrogen-containing ligand-ruthenium-based catalyst.

[0050] Example 13 In a 100mL beaker, add 0.0119g of N-methylimidazole to 20mL of anhydrous ethanol and sonicate for 5-10 minutes. Add 7.555mL of ruthenium chloride trihydrate in ethanol (at a concentration of 0.01g / mL) and sonicate for 5-10 minutes. Stir at room temperature for 6-8 hours. Then, add 2.8131g of coconut shell activated carbon while stirring and stir for 12-18 hours. Then, place the mixture in a 90°C waterbath for 7 hours, filter, and wash three to four times with 400mL of ultrapure water and then 100mL of anhydrous ethanol. Finally, dry in a 70°C vacuum oven for 15 hours to obtain a supported nitrogen-containing ligand-ruthenium-based catalyst.

[0051] Example 14 In a 100mL beaker, add 0.0119g of N-methylimidazole to 20mL of anhydrous ethanol and sonicate for 5-10 minutes. Add 7.555mL of ruthenium chloride trihydrate in ethanol (at a concentration of 0.01g / mL) and sonicate for 5-10 minutes. Stir at room temperature for 6-8 hours. Then, add 2.8131g of coconut shell activated carbon while stirring and stir for 12-18 hours. Then, place the mixture in an 85°C waterbath for 7 hours, filter, and wash three to four times with 400mL of ultrapure water and then 100mL of anhydrous ethanol. Finally, dry in a vacuum oven at 65°C for 17 hours to obtain a supported nitrogen-containing ligand-ruthenium-based catalyst.

[0052] Comparative Example In a 100mL beaker, add 7.555mL of ruthenium chloride trihydrate in ethanol (at a concentration of 0.01g / mL) to 20mL of ultrapure water, ultrasonically treat for 5-10 minutes, and then add 2.8605g of activated carbon while stirring. Stir for 12-18 hours. Place in a 70°C waterbath for 8 hours, filter, and wash three to four times with 400mL of ultrapure water and then 100mL of anhydrous ethanol. Finally, dry in a vacuum oven at 60°C for 18 hours to obtain the catalyst, designated Ru / AC.

[0053] To test the catalytic reaction performance of Examples 1 to 10 and the comparative example, 1-hexene and triethoxysilane were added to a reaction tube in sequence. The reaction tube was placed on a magnetic stirrer with a heating block and stirred for 3 minutes. 0.1460 g of the catalyst prepared in Examples 1 to 10 and the comparative example was taken. The reaction was carried out for 6 hours at 60°C, 500 rpm, and a molar ratio of 1-hexene to triethoxysilane of 1:1. The 1-hexene conversion (%) and n-hexyltriethoxysilane selectivity (%) were measured by GC chromatography. The total weight of the catalyst was calculated as follows: m 总 =m 载体 +m 稳定态金属前驱体The calculation method for 1% catalyst loading is: n Ru : n 1-己烯 =1:1500,m Ru :m 总 = 1%; The mixture entering the GC gas chromatograph is mainly 1-hexene, triethoxysilane, n-hexyltriethoxysilane, α-addition products, and tetraethoxysilane. Occasionally, very small amounts of olefin dimers and dehydrogenation products are produced. 1-hexene is quantified using an internal standard, n-heptane; the selectivity of n-hexyltriethoxysilane is calculated using the peak area normalization method. Due to the conservation of mass before and after the reaction, the reaction mass can be considered a constant in the system. The 1-hexene conversion rate ( X A ) and n-hexyltriethoxysilane selectivity (S β ) is calculated as follows: Calculation method of 1-hexene conversion rate: X A =(n A0 -n A ) / n A0 *100%, the average value of 3 measurements; Calculation method of n-hexyltriethoxysilane selectivity: S β =Ψ β / I *100%, take the average value of 3 measurements.

[0054] Among them, n A0 、n A , Ψ β and I represent the initial molar amount of 1-hexene in the mixture, the remaining molar amount of 1-hexene, the peak area of ​​n-hexyltriethoxysilane and the sum of the peak areas of the product. The results are shown in the following table:

[0055] Combine Figure 2 and Figure 3 It can be seen that the addition of nitrogen-containing ligands significantly improved the conversion of 1-hexene and the selectivity of n-hexyltriethoxysilane. When the ratio of ruthenium precursor to the optimal nitrogen-containing ligand N-methylimidazole was 2:1, the conversion of 1-hexene was 68.84%, which was 21.85% higher than the comparative catalyst Ru / AC. Figures 4 to 6 This may be due to the introduction of the nitrogen-containing ligand N-methylimidazole, which strengthens the interaction between the formed metal species and the carrier, and can improve the high dispersion of the metal species on the activated carbon. At the same time, the formed Ru-N bond has a strong adsorption capacity for the electron-deficient group (1-hexene), thereby promoting the reaction.

[0056] See also Figures 7 and 8The following table shows the Ru content of each catalyst measured by inductively coupled plasma (IPC) and the relative content of Ru(0) species in the catalyst. It can be seen that the presence of nitrogen-containing ligands may be able to regulate the valence state of the metallic ruthenium species, making it tend to form low-valent ruthenium active species, so that the catalyst exhibits significant catalytic activity and selectivity in the reaction. As the ratio of ruthenium precursor to nitrogen-containing ligand increases, the actual ruthenium loading gradually increases. When the ratio reaches 2:1, the catalyst activity reaches the best. Thereafter, as the ratio of ruthenium precursor to nitrogen-containing ligand continues to increase, the catalytic activity of the catalyst weakens.

[0057]

[0058]

[0059] The present invention also provides the use of the above-mentioned supported nitrogen-containing ligand-ruthenium-based catalyst for the catalytic preparation of n-hexyltriethoxysilane. The reaction parameters for the olefin hydrosilylation reaction are: a reaction temperature of 50-60°C, a speed of 400-1000 rpm, a molar ratio of 1-hexene to triethoxysilane of (1:1.5) to (1.5:1), a molar ratio of Ru to 1-hexene of (1:3000) to (1:1500), and a theoretical Ru loading of 0.5% to 1.5%.

[0060] Among them, the main reactions involved in the hydrosilylation reaction of olefins include: Main reaction:

[0061] Non-polymerization side reactions:

[0062] Polymerization side reactions:

[0063] . The catalyst is used in the process of generating n-hexyltriethoxysilane through the hydrosilylation reaction of olefins, and has the characteristics of simple use, low cost, high activity, etc., and has good economic and industrial application value.

[0064] In summary, the present invention provides a supported nitrogen-containing ligand-ruthenium-based catalyst, a preparation method and an application thereof, which ensures the anchoring and high dispersion of the active substance ruthenium on activated carbon by utilizing the interaction force between N-substituted imidazole compounds and metallic ruthenium, thereby avoiding catalyst deactivation due to agglomeration. Due to electron transfer between the N-substituted imidazole compounds and the metal precursor, a Ru-N bond is formed, which stabilizes the low-valent ruthenium active species and further improves the adsorption capacity of the catalyst for the reactant 1-hexene, thereby significantly improving the activity of the catalyst. At the same time, the addition of N-substituted imidazole compounds can cause the ruthenium species to be deposited on the activated carbon, thereby reducing the loss of precious metal ruthenium during the catalyst preparation process and avoiding the reduction of catalyst activity due to the loss of precious metal ruthenium. Compared with other multiphase catalysts prepared from precious metals, it has the characteristics of low cost and good activity, and has better economic value.

[0065] The above description is merely a preferred embodiment of the present invention and is not intended to impose any limitation on the technical solution of the present invention. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can also be subjected to several simple modifications and replacements, and these modifications and replacements are also within the scope of protection covered by the claims.

Claims

1. A supported nitrogen-containing ligand-ruthenium-based catalyst, characterized in that: The raw material components include a carrier, a ligand and a stable metal precursor; the stable metal precursor is a ruthenium salt, the carrier is activated carbon, and the ligand is an N-substituted imidazole compound; the molar ratio of the stable metal precursor to the ligand is (4:1) to (1:2), and the mass of ruthenium in the stable metal precursor is 0.6% to 1.2% of the mass of the carrier.

2. The supported nitrogen-containing ligand-ruthenium-based catalyst according to claim 1, characterized in that: The stable metal precursor is RuCl3.

3. The supported nitrogen-containing ligand-ruthenium-based catalyst according to claim 1, characterized in that: The ligand is N-methylimidazole or N-allylimidazole.

4. The supported nitrogen-containing ligand-ruthenium-based catalyst according to claim 1, characterized in that: The carrier is wood activated carbon.

5. The supported nitrogen-containing ligand-ruthenium-based catalyst according to claim 1, characterized in that: The carrier is coconut shell activated carbon.

6. The method for preparing a supported nitrogen-containing ligand-ruthenium-based catalyst according to claim 1, characterized in that: The molar ratio of the stable metal precursor to the ligand is 2:

1.

7. A method for preparing a supported nitrogen-containing ligand-ruthenium-based catalyst according to any one of claims 1 to 6, characterized in that: include: The ligand, the stable metal precursor and the carrier are mixed in anhydrous ethanol to form a mixed solution; The mixed solution is heated in a constant temperature water bath, filtered, washed and dried to obtain a supported nitrogen-containing ligand-ruthenium-based catalyst.

8. The method for preparing a supported nitrogen-containing ligand-ruthenium-based catalyst according to claim 7, characterized in that: The constant temperature water bath is heated at a temperature of 70° C. to 100° C., and the heating time is 6 to 8 hours.

9. The method for preparing a supported nitrogen-containing ligand-ruthenium-based catalyst according to claim 7, characterized in that: The drying condition is vacuum drying at 60°C to 80°C.

10. Use of the supported nitrogen-containing ligand-ruthenium-based catalyst according to any one of claims 1 to 6 in catalytic preparation of n-hexyltriethoxysilane.

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