Ru-Co-W composite metal catalyst, and preparation method and application thereof
By using the Ru-Co-W composite metal catalyst preparation method, the problems of low yield and poor cycle stability of cobalt-based catalysts in the hydrogenation and deoxygenation of vanillin were solved, and the efficient preparation of 4-methylcyclohexanol was achieved under mild conditions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XIAMEN UNIV
- Filing Date
- 2026-04-20
- Publication Date
- 2026-07-14
AI Technical Summary
Existing cobalt-based catalysts exhibit low yields, poor cycle stability, and demanding reaction conditions in the preparation of cyclohexanol from vanillin via hydrogenation and deoxygenation, making it difficult to effectively convert them into 4-methylcyclohexanol.
The Ru-Co-W composite metal catalyst was prepared by grinding and calcining cobalt and tungsten sources with ascorbic acid to form a composite metal oxide, which was then mixed with ruthenium salt and impregnated and reduced in the presence of a reducing agent to form a Ru-Co-W catalyst. This catalyst promotes H2 heterolytic cracking and the formation of acidic sites, thereby improving catalytic activity.
The efficient conversion of vanillin to 4-methylcyclohexanol was achieved under mild reaction conditions, and the catalyst exhibited high cyclohexanol yield and good recycling performance.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of catalytic synthesis technology, specifically relating to a Ru-Co-W composite metal catalyst, its preparation method, and its application. Background Technology
[0002] With the increasing prevalence of unsustainable consumption patterns and the irreversible depletion of traditional fossil fuel reserves, optimizing the value-added efficiency of renewable bio-based resources has become a key global priority. Biomass, as the most abundant renewable resource on Earth, possesses cellulose and hemicellulose structural components with enormous potential for conversion into high-value-added chemical derivatives, thus attracting considerable scientific interest. Lignin extracted from biomass, due to its more stable phenylpropane structural units, faces significant challenges in high-value conversion. Based on the basic phenolic ring units of lignin, some researchers have linked it to fuels, obtaining lignin-based fuels through pyrolysis or catalytic conversion. Although lignin bio-oil fuels obtained through pyrolysis have a high calorific value, they require harsh reaction conditions and place numerous demands on equipment. Furthermore, the product distribution of lignin pyrolysis is quite complex, making purification difficult. Additionally, lignin contains a high content of monophenolic oxygen and a low content of hydrogen, resulting in the release of more greenhouse gases when burning to produce the same calorific value. All of these issues limit the development of the lignin fuel industry.
[0003] Therefore, the hydrodeoxygenation (HDO) reaction of lignin is considered a solution for achieving efficient and high-value utilization of lignin. Vanillin, a representative product derived from lignin, is widely present in papermaking wastewater, and its abundant functional groups give it extremely high downstream conversion potential. In research on the hydrodeoxygenation reaction of vanillin, cobalt, as the most effective non-precious metal in the hydrogenation reaction of lignin and its derivatives, has received widespread attention. However, for cobalt-based catalysts, cobalt oxide exhibits good high hydrodeoxygenation efficiency, but the preparation of cyclohexanol from vanillin still requires relatively high temperatures and hydrogen pressures. Furthermore, during the reaction, hydrogen overflow reduces cobalt oxide to metallic cobalt, leading to decreased HDO activity and poor cycle performance. To address the insufficient hydrogen activation capacity of cobalt-based catalysts, some studies have combined cobalt with other metals (such as copper, palladium, platinum, and ruthenium), but the reaction conditions remain relatively harsh, and the main product is 4-methylguaiacol rather than 4-methylcyclohexanol. Therefore, it is crucial to study a novel composite metal oxide to improve the efficiency and cycle stability of the preparation of 4-methylcyclohexanol by the hydrogenation and deoxygenation of vanillin. Summary of the Invention
[0004] The purpose of this invention is to address the problems of low yield and poor cycle stability in the preparation of cyclohexanol by the hydrogenation and deoxygenation of vanillin using existing cobalt-based metal catalysts. This invention provides a Ru-Co-W composite metal catalyst, its preparation method, and its application, which can achieve the conversion of vanillin to 4-methylcyclohexanol under relatively mild reaction conditions.
[0005] In a first aspect, the present invention provides a method for preparing a Ru-Co-W composite metal catalyst. The preparation method includes the following steps: S1. Grinding and mixing a cobalt source, a tungsten source, and ascorbic acid, followed by calcination in an oxygen-containing atmosphere to obtain a composite metal oxide; S2. Mixing the obtained composite metal oxide with ruthenium salt and water, followed by impregnation, and then reducing it in the presence of a reducing agent, the resulting product being the Ru-Co-W composite metal catalyst.
[0006] In a preferred embodiment, in step S1, the molar ratio of Co in the cobalt source to W in the tungsten source is 1:(0.1~0.3).
[0007] In a preferred embodiment, in step S1, the molar ratio of the ascorbic acid to the sum of Co in the cobalt source and W in the tungsten source is (0.2~0.6):1.
[0008] In a preferred embodiment, in step S1, the cobalt source is selected from at least one of cobalt nitrate, cobalt chloride, cobalt acetate, and cobalt oxalate; the tungsten source is selected from ammonium paratungstate and / or ammonium tungstate.
[0009] In a preferred embodiment, in step S1, the calcination treatment conditions include: a temperature of 200~500℃ and a time of 1~3h.
[0010] In a preferred embodiment, in step S1, the oxygen-containing atmosphere is an air atmosphere.
[0011] In a preferred embodiment, in step S2, the amount of ruthenium salt used is such that the Ru content in the Ru-Co-W composite metal catalyst is 0.5~5wt%.
[0012] In a preferred embodiment, in step S2, the ruthenium salt is selected from at least one of ruthenium chloride, ruthenium nitrate, and ruthenium sulfate.
[0013] In a preferred embodiment, in step S2, the conditions for the impregnation treatment include: a temperature of 15~30℃ and a time of 0.5~1.0h.
[0014] In a preferred embodiment, in step S2, the reducing agent is sodium borohydride.
[0015] In a preferred embodiment, in step S2, the molar ratio of the reducing agent to Ru in the ruthenium salt is (10~20):1.
[0016] In a preferred embodiment, in step S2, the conditions for the reduction reaction include: a temperature of 15~30℃ and a time of 0.5~2h.
[0017] Secondly, the present invention provides a Ru-Co-W composite metal catalyst prepared by the above method.
[0018] Thirdly, the present invention also provides the application of the above-mentioned Ru-Co-W composite metal catalyst in the preparation of cyclohexanol by hydrogenation deoxygenation of vanillin.
[0019] In a preferred embodiment, the method of application is as follows: the above-mentioned Ru-Co-W composite metal catalyst, vanillin and solvent are added to the reactor, hydrogen is introduced to replace the gas in the reactor and hydrogen is introduced to the reaction pressure, and then the temperature is raised to the reaction temperature to carry out the vanillin hydrogenation deoxygenation reaction. After the reaction is completed, cyclohexanol is obtained in the solution.
[0020] In a preferred embodiment, the concentration of vanillin in the solution formed by vanillin and solvent is 15-25 wt%.
[0021] In a preferred embodiment, the solvent is selected from at least one of water, 1,4-dioxane, n-hexane, ethanol, methanol, and isopropanol.
[0022] In a preferred embodiment, the amount of the Ru-Co-W composite metal catalyst is 30-50 wt% of the vanillin mass.
[0023] In a preferred embodiment, the reaction pressure is 1.0~4.0 MPa.
[0024] In a preferred embodiment, the reaction temperature is 110~170°C.
[0025] In a preferred embodiment, the hydrodeoxygenation reaction takes 2 to 4 hours.
[0026] Beneficial effects: The key to this invention lies in first grinding cobalt source, tungsten source, and ascorbic acid, followed by solid-state sintering. During this process, ascorbic acid forms coordination with Co and undergoes reduction through calcination, resulting in a composite metal oxide (CoWO3). x This composite metal oxide possesses oxygen-rich vacancies and weak Co-O bonds. Ruthenium is then loaded onto the composite metal oxide via a wet impregnation-reduction reaction. The weak Co-O bonds promote the formation of Ru-O-Co sites, and Ru-O-Co interacts with Ru... 0It can form a synergistic effect to promote heterolytic cleavage of H2, thereby forming H bound to O. δ+ And Ru 0 H binding site δ- Unlike homolytically split hydrogen atoms, this unique heterolytically split hydrogen can form in-situ acidic sites and Ru-H sites, which better promote the hydrodeoxygenation reaction. As a result, the Ru-Co-W composite metal catalyst prepared in this way exhibits high catalytic activity in the hydrodeoxygenation of vanillin to produce cyclohexanol (4-methylcyclohexanol). It can achieve high cyclohexanol yield under relatively mild reaction conditions and has good cycle performance. Even at high vanillin concentrations, it still has a high cyclohexanol yield. Detailed Implementation
[0027] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Furthermore, unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present invention.
[0028] The preparation method of the Ru-Co-W composite metal catalyst provided by the present invention includes the following steps: S1. Cobalt source, tungsten source, and ascorbic acid are ground and mixed, and then calcined in an oxygen-containing atmosphere to obtain a composite metal oxide; S2. The obtained composite metal oxide is mixed with ruthenium salt and water and then impregnated. Then, it is reduced in the presence of a reducing agent. The resulting product is the Ru-Co-W composite metal catalyst.
[0029] In this invention, in step S1, the molar ratio of Co in the cobalt source to W in the tungsten source is preferably 1:(0.1~0.3), such as 1:0.1, 1:0.15, 1:0.2, 1:0.25, 1:0.3, or any ratio between them. Since the low-valence Co oxide in the composite metal oxide is the main adsorption site for the oxygen-containing groups in vanillin, and W provides more acidic sites to promote the activation of the adsorption groups, controlling the molar ratio of Co and W within the above-mentioned preferred range is more conducive to the adsorption and activation of vanillin by the Ru-Co-W composite metal catalyst, thereby promoting the hydrodeoxygenation reaction and increasing the yield of cyclohexanol (4-methylcyclohexanol).
[0030] In this invention, in step S1, the molar ratio of ascorbic acid to the sum of Co in the cobalt source and W in the tungsten source is preferably (0.2~0.6):1, such as 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, or any ratio between them. Since ascorbic acid acts as a chelating agent and reducing agent during solid-state sintering, within the above-mentioned preferred dosage range, it is more beneficial to promote the cobalt production process. 2+ The formation of -Ov sites results in the presence of more low-valence Co, weak Co-O bonds, and abundant oxygen vacancies in the resulting composite metal oxide.
[0031] In this invention, in step S1, the cobalt source can be any substance capable of providing cobalt element to calcine in an oxygen-containing atmosphere to obtain a composite metal oxide. Specific examples include, but are not limited to, at least one of cobalt nitrate, cobalt chloride, cobalt acetate, and cobalt oxalate. The tungsten source can be any substance capable of providing tungsten element to calcine in an oxygen-containing atmosphere to obtain a composite metal oxide, and can be ammonium paratungstate and / or ammonium tungstate.
[0032] In this invention, the calcination conditions in step S1 preferably include: a temperature of 200~500℃, such as 200℃, 250℃, 300℃, 350℃, 400℃, 450℃, 500℃, or any value between them; and a time of 1~3h, such as 1h, 1.5h, 2h, 2.5h, 3h, or any value between them. The oxygen-containing atmosphere is preferably an air atmosphere.
[0033] In this invention, in step S2, the amount of ruthenium salt is preferably such that the Ru content in the Ru-Co-W composite metal catalyst is 0.5~5wt%, and the Ru content can be 0.5wt%, 1wt%, 1.5wt%, 2wt%, 3wt%, 4wt%, 5wt%, or any value between them.
[0034] In this invention, in step S2, the ruthenium salt can be any substance that can dissolve in water to provide the ruthenium element required for subsequent impregnation and reduction reactions. Specific examples include, but are not limited to, at least one of ruthenium chloride, ruthenium nitrate, and ruthenium sulfate.
[0035] In this invention, the conditions for the impregnation treatment in step S2 preferably include: a temperature of 15~30℃, such as 15℃, 18℃, 20℃, 22℃, 25℃, 28℃, 30℃ or any value between them; and a time of 0.5~1.0h, such as 0.5h, 0.6h, 0.7h, 0.8h, 0.9h, 1.0h or any value between them.
[0036] In this invention, in step S2, the reducing agent is preferably sodium borohydride. The molar ratio of the reducing agent to Ru in the ruthenium salt is preferably (10~20):1, such as 10:1, 12:1, 15:1, 18:1, 20:1, or any ratio between them.
[0037] In this invention, the conditions for the reduction reaction in step S2 preferably include: a temperature of 15~30℃, such as 15℃, 18℃, 20℃, 22℃, 25℃, 28℃, 30℃ or any value between them; and a time of 0.5~2h, such as 0.5h, 1h, 1.5h, 2h or any value between them.
[0038] This invention also provides the application of the Ru-Co-W composite metal catalyst prepared by the above method in the preparation of cyclohexanol by hydrogenation deoxygenation of vanillin.
[0039] Specifically, the application method can be as follows: add the Ru-Co-W composite metal catalyst, vanillin and solvent to the reactor, introduce hydrogen to replace the gas in the reactor and fill the reactor with hydrogen to the reaction pressure, then heat to the reaction temperature to carry out the vanillin hydrogenation deoxygenation reaction, and after the reaction is completed, cyclohexanol is obtained in the solution.
[0040] In this invention, the concentration of vanillin in the solution formed by vanillin and solvent is preferably 15-25 wt%, such as 15 wt%, 18 wt%, 20 wt%, 22 wt%, 25 wt%, or any value between them.
[0041] In this invention, specific examples of the solvent include, but are not limited to, at least one of water, 1,4-dioxane, n-hexane, ethanol, methanol, and isopropanol, with water being particularly preferred.
[0042] In this invention, the preferred amount of the Ru-Co-W composite metal catalyst is 30-50 wt% of the vanillin mass, such as 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, or any value between them. In this invention, the reaction pressure is preferably 1.0~4.0 MPa, such as 1.0 MPa, 1.5 MPa, 2.0 MPa, 2.5 MPa, 3.0 MPa, 3.5 MPa, 4.0 MPa or any value between them.
[0043] In this invention, the reaction temperature is preferably 110~170℃, such as 110℃, 120℃, 130℃, 140℃, 150℃, 155℃, 160℃, 165℃, 170℃ or any value between them.
[0044] In this invention, the preferred time for the hydrodeoxygenation reaction is 2 to 4 hours, such as 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours or any value between them.
[0045] The present invention will be described in detail below through specific embodiments. These embodiments are intended to explain the invention and should not be construed as limiting it. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.
[0046] Example 1 This embodiment illustrates the preparation of a Ru-Co-W composite metal catalyst and a method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin, as detailed below: (1) Preparation of Ru-Co-W composite metal catalyst: 9 mmol of Co(NO3)2·6H2O and 0.083 mmol of ammonium paratungstate ((NH4)2) were added. 10 W 12 O 41 4 mmol of ascorbic acid (VC) and 4 mmol of VC were mechanically ground in a mortar for 5 min. The resulting precursor mixture was then calcined in air at 300 °C for 2 h. After cooling, a composite metal oxide, denoted as CoWO, was obtained. x -VC-1; 1.00g CoWO x -VC-1, 0.07 g RuCl3·6H2O, and 20.00 g deionized water were added to a 100 mL beaker and stirred for 0.5 h. Then, 30 mL of sodium borohydride solution (NaBH4 to RuCl3·6H2O molar ratio 10:1) was added to the suspension, and the mixture was stirred for another 2 h. The solid was then collected by filtration and dried under vacuum (60 °C, 12 h) to obtain the Ru-Co-W composite metal catalyst, denoted as Ru-CoWO. x -VC-1. ICP testing confirmed Ru-CoWO x The VC-1 catalyst contains 2.1 wt% Ru and has a cobalt / tungsten molar ratio of approximately 9:1.
[0047] (2) Method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin: 1.00 g of vanillin and 4.00 g of deionized water are added to the reactor, followed by 0.4 g of Ru-CoWO3. x -VC-1 catalyst, after being replaced with high-purity hydrogen five times, the reactor was sealed after being filled with hydrogen to 2.5MPa. The reactor was then heated to 160℃ and maintained for 2.5h. The mixture after the reaction was completed was taken out and tested. The test results are listed in Table 1.
[0048] Example 2 This embodiment illustrates the preparation of a Ru-Co-W composite metal catalyst and a method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin, as detailed below: (1) Preparation of Ru-Co-W composite metal catalyst: The Ru-Co-W composite metal catalyst was prepared according to the method in Example 1 (1), and is denoted as Ru-CoWO. x -VC-1. ICP testing confirmed Ru-CoWO x The VC-1 catalyst contains 2.1 wt% Ru and has a cobalt / tungsten molar ratio of approximately 9:1.
[0049] (2) Method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin: Add 0.75 g of vanillin and 4.25 g of deionized water to the reactor, and then add 0.3 g of Ru-CoWO4. x -VC-1 catalyst, after being replaced with high-purity hydrogen five times, the reactor was sealed after being filled with hydrogen to 2.5MPa. The reactor was then heated to 160℃ and maintained for 2.5h. The mixture after the reaction was completed was taken out and tested. The test results are listed in Table 1.
[0050] Example 3 This embodiment illustrates the preparation of a Ru-Co-W composite metal catalyst and a method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin, as detailed below: (1) Preparation of Ru-Co-W composite metal catalyst: The Ru-Co-W composite metal catalyst was prepared according to the method in Example 1 (1), and is denoted as Ru-CoWO. x -VC-1. ICP testing confirmed Ru-CoWO x The VC-1 catalyst contains 2.1 wt% Ru and has a cobalt / tungsten molar ratio of approximately 9:1.
[0051] (2) Method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin: Add 1.25 g of vanillin and 3.75 g of deionized water to the reactor, and then add 0.5 g of Ru-CoWO4. x -VC-1 catalyst, after being replaced with high-purity hydrogen five times, the reactor was sealed after being filled with hydrogen to 2.5MPa. The reactor was then heated to 160℃ and maintained for 2.5h. The mixture after the reaction was completed was taken out and tested. The test results are listed in Table 1.
[0052] Example 4 This embodiment illustrates the preparation of a Ru-Co-W composite metal catalyst and a method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin, as detailed below: (1) Preparation of Ru-Co-W composite metal catalyst: The Ru-Co-W composite metal catalyst was prepared according to the method in (1) of Example 1, except that the amount of ascorbic acid (VC) was 2 mmol, the calcination temperature was 400℃, and the other conditions were the same as in (1) of Example 1. The Ru-Co-W composite metal catalyst was thus prepared and is denoted as Ru-CoWO. x -VC-2. ICP testing confirmed Ru-CoWO x The VC-2 catalyst contains 2.1 wt% Ru and has a cobalt / tungsten molar ratio of approximately 9:1.
[0053] (2) Method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin: 1.00 g of vanillin and 4.00 g of deionized water are added to the reactor, followed by 0.4 g of Ru-CoWO3. x -VC-2 catalyst, after being replaced with high-purity hydrogen five times, the reactor was sealed after being filled with hydrogen to 2.5MPa. The reactor was then heated to 160℃ and maintained for 2.5h. The mixture after the reaction was completed was taken out and tested. The test results are listed in Table 1.
[0054] Example 5 This embodiment illustrates the preparation of a Ru-Co-W composite metal catalyst and a method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin, as detailed below: (1) Preparation of Ru-Co-W composite metal catalyst: The Ru-Co-W composite metal catalyst was prepared according to the method in (1) of Example 1, except that the amount of ascorbic acid (VC) was 6 mmol, the calcination temperature was 500℃, and the other conditions were the same as in (1) of Example 1. Thus, the Ru-Co-W composite metal catalyst was prepared and denoted as Ru-CoWO. x -VC-3. ICP testing confirmed Ru-CoWO3. x The VC-3 catalyst contains 2.1 wt% Ru and has a cobalt / tungsten molar ratio of approximately 9:1.
[0055] (2) Method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin: 1.00 g of vanillin and 4.00 g of deionized water are added to the reactor, followed by 0.4 g of Ru-CoWO3. x -VC-3 catalyst, after being replaced with high-purity hydrogen five times, the reactor was sealed after being filled with hydrogen to 2.5MPa. The reactor was then heated to 160℃ and maintained for 2.5h. The mixture after the reaction was completed was taken out and tested. The test results are listed in Table 1.
[0056] Example 6 This embodiment illustrates the preparation of a Ru-Co-W composite metal catalyst and a method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin, as detailed below: (1) Preparation of Ru-Co-W composite metal catalyst: The Ru-Co-W composite metal catalyst was prepared according to the method in Example 1 (1), except that the amount of Co(NO3)2·6H2O was 8 mmol and the amount of ammonium paratungstate ((NH4) 10 W 12 O 41 The amount of 0.18 mmol was used, and all other conditions were the same as in Example 1 (1). Thus, the Ru-Co-W composite metal catalyst was prepared and denoted as Ru-CoWO. x -VC-4. ICP testing confirmed Ru-CoWO x The VC-4 catalyst contains 2.1 wt% Ru and has a cobalt / tungsten molar ratio of approximately 1:0.27.
[0057] (2) Method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin: 1.00 g of vanillin and 4.00 g of deionized water are added to the reactor, followed by 0.4 g of Ru-CoWO3. x -VC-4 catalyst, after being replaced with high-purity hydrogen five times, the reactor was sealed after being filled with hydrogen to 2.5MPa. The reactor was then heated to 160℃ and maintained for 2.5h. The mixture after the reaction was completed was taken out and tested. The test results are listed in Table 1.
[0058] Example 7 This embodiment illustrates the preparation of a Ru-Co-W composite metal catalyst and a method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin, as detailed below: (1) Preparation of Ru-Co-W composite metal catalyst: The Ru-Co-W composite metal catalyst was prepared according to the method in (1) of Example 1, except that the amount of RuCl3·6H2O was 0.04g, and the other conditions were the same as in (1) of Example 1. The Ru-Co-W composite metal catalyst was thus prepared and is denoted as Ru-CoWO. x -VC-5. ICP testing confirmed Ru-CoWO x The VC-5 catalyst contains 1.2 wt% Ru and has a cobalt / tungsten molar ratio of approximately 9:1.
[0059] (2) Method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin: 1.00 g of vanillin and 4.00 g of deionized water are added to the reactor, followed by 0.4 g of Ru-CoWO3. x -VC-5 catalyst, after being replaced with high-purity hydrogen five times, the reactor was sealed after being filled with hydrogen to 2.5MPa. The reactor was then heated to 160℃ and maintained for 2.5h. The mixture after the reaction was completed was taken out and tested. The test results are listed in Table 1.
[0060] Example 8 This embodiment illustrates the preparation of a Ru-Co-W composite metal catalyst and a method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin, as detailed below: (1) Preparation of Ru-Co-W composite metal catalyst: The Ru-Co-W composite metal catalyst was prepared according to the method in (1) of Example 1, except that the amount of RuCl3·6H2O was 0.10 g, and the other conditions were the same as in (1) of Example 1. The Ru-Co-W composite metal catalyst was thus prepared and is denoted as Ru-CoWO. x -VC-6. ICP testing confirmed Ru-CoWO x The VC-6 catalyst contains 3.0 wt% Ru and has a cobalt / tungsten molar ratio of approximately 9:1.
[0061] (2) Method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin: 1.00 g of vanillin and 4.00 g of deionized water are added to the reactor, followed by 0.4 g of Ru-CoWO3. x -VC-6 catalyst, after being replaced with high-purity hydrogen five times, the reactor was sealed after being filled with hydrogen to 2.5MPa. The reactor was then heated to 160℃ and maintained for 2.5h. The mixture after the reaction was completed was taken out and tested. The test results are listed in Table 1.
[0062] Example 9 This embodiment illustrates the preparation of a Ru-Co-W composite metal catalyst and a method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin, as detailed below: (1) Preparation of Ru-Co-W composite metal catalyst: The Ru-Co-W composite metal catalyst was prepared according to the method in Example 1 (1), except that ammonium paratungstate ((NH4)) was used. 10 W 12 O 41 The amount of 0.5 mmol was used, and all other conditions were the same as in Example 1 (1). Thus, the Ru-Co-W composite metal catalyst was prepared and denoted as Ru-CoWO. x -VC-7. ICP testing confirmed Ru-CoWO x The VC-8 catalyst contains 2.1 wt% Ru and has a cobalt / tungsten molar ratio of approximately 1:0.67.
[0063] (2) Method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin: 1.00 g of vanillin and 4.00 g of deionized water are added to the reactor, followed by 0.4 g of Ru-CoWO3. x-VC-7 catalyst, after purging the gas with high-purity hydrogen five times, the reactor was sealed after being filled with hydrogen to 2.5MPa. The reactor was then heated to 160℃ and maintained for 2.5h. The mixture after the reaction was completed was taken out and tested. The test results are listed in Table 1.
[0064] Example 10 This embodiment illustrates the preparation of a Ru-Co-W composite metal catalyst and a method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin, as detailed below: (1) Preparation of Ru-Co-W composite metal catalyst: The Ru-Co-W composite metal catalyst was prepared according to the method in Example 1 (1), except that ammonium paratungstate ((NH4)) was used. 10 W 12 O 41 The amount of 0.8 mmol was used, and all other conditions were the same as in Example 1 (1). Thus, the Ru-Co-W composite metal catalyst was prepared and denoted as Ru-CoWO. x -VC-8. ICP testing confirmed Ru-CoWO x The VC-8 catalyst contains 2.1 wt% Ru and has a cobalt / tungsten molar ratio of approximately 1:1.07.
[0065] (2) Method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin: 1.00 g of vanillin and 4.00 g of deionized water are added to the reactor, followed by 0.4 g of Ru-CoWO3. x -VC-8 catalyst, after being replaced with high-purity hydrogen five times, the reactor was sealed after being filled with hydrogen to 2.5MPa. The reactor was then heated to 160℃ and maintained for 2.5h. The mixture after the reaction was completed was taken out and tested. The test results are listed in Table 1.
[0066] Comparative Example 1 This comparative example illustrates the preparation of a reference metal catalyst and the method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin, as detailed below: (1) Preparation of reference metal catalyst: The reference metal catalyst was prepared according to the method in (1) of Example 1, except that 0.083 mmol of ammonium paratungstate was replaced by 1 mmol of Co(NO3)2·6H2O. All other conditions were the same as in (1) of Example 1. The reference metal catalyst was thus prepared and denoted as Ru-CoO x -VC-D1. ICP testing showed Ru-CoO x The Ru content in the -VC-D1 catalyst is 2.1 wt%.
[0067] (2) Method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin: Add 1.00 g of vanillin and 4.00 g of deionized water to the reactor, and then add 0.4 g of Ru-CoOx -VC-D1 catalyst, after being replaced with high-purity hydrogen five times, the reactor was sealed after being filled with hydrogen to 2.5MPa. The reactor was then heated to 160℃ and maintained for 2.5h. The mixture after the reaction was completed was taken out and tested. The test results are listed in Table 1.
[0068] Comparative Example 2 This comparative example illustrates the preparation of a reference metal catalyst and the method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin, as detailed below: (1) Preparation of reference metal catalyst: The reference metal catalyst was prepared according to the method in (1) of Example 1, except that 9 mmol of Co(NO3)2·6H2O was replaced by 0.75 mmol of ammonium paratungstate. All other conditions were the same as in (1) of Example 1. The reference metal catalyst was thus prepared and denoted as Ru-WO. x -VC-D2. ICP testing confirmed Ru-WO x The Ru content in the -VC-D2 catalyst is 2.1 wt%.
[0069] (2) Method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin: 1.00 g of vanillin and 4.00 g of deionized water are added to the reactor, followed by 0.4 g of Ru-WO3. x -VC-D2 catalyst, after being replaced with high-purity hydrogen five times, the reactor was sealed after being filled with hydrogen to 2.5MPa. The reactor was then heated to 160℃ and maintained for 2.5h. The mixture after the reaction was completed was taken out and tested. The test results are listed in Table 1.
[0070] Comparative Example 3 This comparative example illustrates the preparation of a reference metal catalyst and the method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin, as detailed below: (1) Preparation of reference metal catalyst: 9 mmol of Co(NO3)2·6H2O and 1.67 mmol of ammonium paratungstate ((NH4)2) were prepared. 10 W 12 O 41 4 mmol of ascorbic acid (VC) and 4 mmol of VC were mechanically ground in a mortar for 5 min. The resulting precursor mixture was then calcined in air at 300 °C for 2 h. After cooling, a composite metal oxide, denoted as CoWO, was obtained. x -D3.
[0071] (2) Method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin: Add 1.00 g of vanillin and 4.00 g of deionized water to the reactor, and then add 0.4 g of CoWO4. x-D3 catalyst, after being replaced with high-purity hydrogen five times, the reactor was sealed after being filled with hydrogen to 2.5 MPa. The reactor was then heated to 160℃ and maintained for 2.5 h. The mixture after the reaction was completed was taken out and tested. The test results are listed in Table 1.
[0072] Comparative Example 4 This comparative example illustrates the preparation of a reference metal catalyst and the method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin, as detailed below: (1) Preparation of reference metal catalyst: The reference metal catalyst was prepared according to the method in (1) of Example 1, except that the amount of ascorbic acid (VC) was 0, and the other conditions were the same as in (1) of Example 1. The reference metal catalyst was thus prepared and is denoted as Ru-CoWO. x -D4. ICP testing confirmed Ru-CoWO x The Ru content in the -D4 catalyst is 2.0 wt%.
[0073] (2) Method for preparing cyclohexanol by hydrogenation and deoxygenation of vanillin: 1.00 g of vanillin and 4.00 g of deionized water are added to the reactor, followed by 0.4 g of Ru-CoWO3. x -D4 catalyst, after being replaced with high-purity hydrogen five times, the reactor was sealed after being filled with hydrogen to 2.5 MPa. The reactor was then heated to 160℃ and maintained for 2.5 h. The mixture after the reaction was completed was taken out and tested. The test results are listed in Table 1.
[0074] Test case (1) The reaction mixtures obtained from the above examples and comparative examples were analyzed for components and content by high performance liquid chromatography, and the conversion rate of vanillin and the yield and selectivity of 4-methylcyclohexanol were calculated according to formulas (1), (2) and (3), respectively. The results are shown in Table 1.
[0075] Formula (1) Formula (2) Formula (3) (2) The catalysts prepared in the above examples and comparative examples were tested three times in accordance with the method in (2) of Example 1. The reaction mixture obtained from the last test was used to calculate the yield of 4-methylcyclohexanol in accordance with the above method. The results are shown in Table 1.
[0076] Table 1
[0077] As shown in Table 1, compared with Comparative Examples 1-4, the Ru-Co-W composite metal catalysts prepared in Examples 1-10 of this invention simultaneously possess high 4-methylcyclohexanol yield, selectivity, and good cycling stability.
[0078] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.
Claims
1. A method for preparing a Ru-Co-W composite metal catalyst, characterized in that, The preparation method includes the following steps: S1. Cobalt source, tungsten source, and ascorbic acid are ground and mixed, and then calcined in an oxygen-containing atmosphere to obtain a composite metal oxide; S2. The obtained composite metal oxide is mixed with ruthenium salt and water and then impregnated. Then, it is reduced in the presence of a reducing agent. The resulting product is the Ru-Co-W composite metal catalyst.
2. The preparation method of the Ru-Co-W composite metal catalyst according to claim 1, characterized in that, In step S1, the molar ratio of Co in the cobalt source to W in the tungsten source is 1:(0.1~0.3); Preferably, the molar ratio of the ascorbic acid to the sum of Co in the cobalt source and W in the tungsten source is (0.2~0.6):
1.
3. The preparation method of the Ru-Co-W composite metal catalyst according to claim 1, characterized in that, In step S1, the cobalt source is selected from at least one of cobalt nitrate, cobalt chloride, cobalt acetate, and cobalt oxalate; the tungsten source is ammonium paratungstate and / or ammonium tungstate.
4. The preparation method of the Ru-Co-W composite metal catalyst according to claim 1, characterized in that, In step S1, the calcination conditions include: a temperature of 200~500℃ and a time of 1~3h; Preferably, the oxygen-containing atmosphere is an air atmosphere.
5. The method for preparing the Ru-Co-W composite metal catalyst according to claim 1, characterized in that, In step S2, the amount of ruthenium salt used is such that the Ru content in the Ru-Co-W composite metal catalyst is 0.5~5wt%; Preferably, the ruthenium salt is selected from at least one of ruthenium chloride, ruthenium nitrate, and ruthenium sulfate; Preferably, the conditions for the impregnation treatment include: a temperature of 15~30℃ and a time of 0.5~1.0h.
6. The method for preparing the Ru-Co-W composite metal catalyst according to claim 1, characterized in that, In step S2, the reducing agent is sodium borohydride; Preferably, the molar ratio of the reducing agent to Ru in the ruthenium salt is (10~20):1; Preferably, the conditions for the reduction reaction include: a temperature of 15~30℃ and a time of 0.5~2h.
7. The Ru-Co-W composite metal catalyst prepared by the method according to any one of claims 1 to 6.
8. The application of the Ru-Co-W composite metal catalyst according to claim 7 in the preparation of cyclohexanol by hydrogenation deoxygenation of vanillin.
9. The application of the Ru-Co-W composite metal catalyst according to claim 8 in the preparation of cyclohexanol by hydrogenation deoxygenation of vanillin, characterized in that, The method of application is as follows: the Ru-Co-W composite metal catalyst, vanillin and solvent as described in claim 7 are added to the reactor, hydrogen is introduced to replace the gas in the reactor and hydrogen is introduced to the reaction pressure, and then the temperature is raised to the reaction temperature to carry out the vanillin hydrogenation deoxygenation reaction. After the reaction is completed, cyclohexanol is obtained in the solution.
10. The application of the Ru-Co-W composite metal catalyst according to claim 8 in the preparation of cyclohexanol by hydrogenation deoxygenation of vanillin, characterized in that, The concentration of vanillin in the solution formed by vanillin and solvent is 15-25 wt%. Preferably, the solvent is selected from at least one of water, 1,4-dioxane, n-hexane, ethanol, methanol, and isopropanol; Preferably, the amount of the Ru-Co-W composite metal catalyst is 30-50 wt% of the mass of vanillin. Preferably, the reaction pressure is 1.0~4.0 MPa; Preferably, the reaction temperature is 110~170℃; Preferably, the hydrogenation deoxygenation reaction takes 2 to 4 hours.