Ru single-metal catalyst, preparation method and application of Ru single-metal catalyst in electro-synthesis of cyclohexanecarboxylic acid
By preparing Ru single metal catalyst on a carbon cloth support, it is used for electrocatalytic hydrogenation reaction of cyclohexachloride, the problems of high temperature and high pressure in the synthesis of existing cyclohexachloride and high cost of precious metal catalysts are solved, and the efficiency of cyclohexachloride is achieved , economical and environmentally friendly electrocatalytic synthesis.
Patent Information
- Application Number
- CN202310733720.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-06-20
- Publication Date
- 2024-12-20
AI Technical Summary
The existing green synthesis method of cyclohexanoic acid relies on hydrogenation of thermal catalysts, high reaction conditions, high temperature and high pressure, and the commonly used precious metal catalysts are costly, so the environmentally friendly synthesis needs of cyclohexanoic acid have not been met.
The Ru single metal catalyst was prepared on a carbon cloth support by cyclic voltammetry. It was used for electrocatalytic hydrogenation reaction of cyclohexanoic acid, which reduced the catalyst cost and improved the cycle stability.
The efficient electrocatalytic synthesis of cyclohexanoic acid is achieved, which reduces the catalyst price, and the catalyst has ultra-high cycling stability and high active hydrogen generation ability, which improves the utilization rate of metal atoms.
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Figure CN119162600A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of catalyst preparation, and in particular to a Ru single metal catalyst, a preparation method and application in cyclohexanecarboxylic acid electrosynthesis. Background Art
[0002] Cyclohexanecarboxylic acid is widely used in organic chemical industry. It can be used to synthesize UV curing agent, used as vulcanized rubber solubilizer and petroleum clarifier. It can also be used to synthesize medicine, pesticide and other organic compounds. In addition, cyclohexanecarboxylic acid has a wide variety of derivatives such as cyclohexanecarboxylic acid esters, trans-4-isopropylcyclohexanecarboxylic acid, p-aminocyclohexanecarboxylic acid, etc., which are important chemical and pharmaceutical synthesis intermediates.
[0003] In existing reports, the preparation of cyclohexanecarboxylic acid from benzoic acid is mainly based on thermal catalytic hydrogenation. The metals currently used in catalysts are mainly rhodium, iridium, platinum, ruthenium, palladium, nickel, etc. Qiu et al. used nitrogen-doped ZIF-8 to form a porous two-dimensional nanotube structure for loading ruthenium nanoparticles. After reacting at 353K and 1.0MPa for 1.5 hours, the conversion rate of 0.5mM benzoic acid reached 74.2%, and the selectivity reached 99%; Zhang et al. prepared C-TiO2 doped with ruthenium metal as a catalyst, reacted at 343K and 2.5MPa for 3 hours, and the conversion rate and selectivity of 0.5mM benzoic acid reached 100%. Recently, Gao et al. used ammonia evaporation method (AE) to load active nickel on mSiO2 and successfully prepared Ni / mSiO2-AE nanocatalyst. The catalyst showed excellent catalytic performance in the selective hydrogenation reaction of benzoic acid, with a conversion rate of benzoic acid of 98.9% and a selectivity of 99.1% for cyclohexanecarboxylic acid. In addition, the catalyst can be recycled four times without significant loss of its initial activity. However, these methods all obtain cyclohexanecarboxylic acid by hydrogenation of hot catalysts, that is, hydrogen is introduced to react under high temperature and high pressure conditions. Their reaction pressures are mostly 0.1-10 MPa, and the reaction temperature is 50-200°C. In addition, the organic solvents used in the reaction system are mostly organic solvents such as cyclohexane, hexane, and tetrahydrofuran. Therefore, the green synthesis of cyclohexanecarboxylic acid still requires new methods.
[0004] Electrocatalytic hydrogenation is a hydrogenation process that replaces traditional chemical fuels. In existing reports, during electrocatalytic hydrogenation, the catalyst often uses more than two precious metals such as Pt, Rh, Pd, etc., which are expensive and costly. For example: Patent application number: CN2022102935501, the invention name is a PtRu alloy catalyst and preparation method and application in cyclohexanecarboxylic acid electrosynthesis, and the prepared catalyst is made of two precious metals as raw materials. Summary of the invention
[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a Ru single metal catalyst.
[0006] The second object of the present invention is to provide a method for preparing a Ru single metal catalyst.
[0007] The third object of the present invention is to provide an application of a Ru single metal catalyst in the electrosynthesis of cyclohexanecarboxylic acid.
[0008] The technical solution of the present invention is summarized as follows:
[0009] The preparation method of Ru single metal catalyst comprises the following steps:
[0010] 1) dissolving ruthenium chloride in a sodium sulfate aqueous solution with a concentration of 0.3-0.8M, stirring evenly, and obtaining a ruthenium chloride solution as an electrolyte;
[0011] 2) Cut the carbon cloth into a large rectangular piece and a small rectangular piece, use the large rectangular piece as the counter electrode, the small rectangular piece as the working electrode, and the Ag / AgCl electrode as the reference electrode. In a single-cell electrolytic cell containing the electrolyte obtained in step 1), vertically place the counter electrode, the working electrode, and the reference electrode from left to right, and set the counter electrode and the working electrode in parallel, so that the center of the counter electrode and the center of the working electrode are on the same horizontal line. Use cyclic voltammetry, set the scanning number to 100 to 200, the voltage range to -0.9V to 1.2V, and the scanning rate to 0.05-0.2V / s for electroplating; after the electroplating is completed, take out the electroplated working electrode, wash it with water and anhydrous ethanol in turn, and dry it to obtain a Ru single metal catalyst.
[0012] The concentration of the sodium sulfate aqueous solution is preferably 0.5M.
[0013] Step 1) The concentration of the ruthenium chloride solution is 3-7 mM.
[0014] The size of the large rectangular piece is preferably (3.5-4) cm×(2.5-3) cm×0.1 cm; the size of the small rectangular piece is preferably (3-3.5) cm×1.5 cm×0.1 cm.
[0015] The voltage range is preferably -0.8 to 1.1V.
[0016] The Ru single metal catalyst prepared by the above method.
[0017] Application of the above-mentioned Ru single metal catalyst in the electrosynthesis of cyclohexanecarboxylic acid.
[0018] The above application preferably comprises the following steps: using an H-type electrolytic cell, placing an anolyte and an anode Pt sheet in the anode cell, placing a cathode electrolyte and a cathode in the cathode cell, wherein the cathode is a Ru single metal catalyst, the anolyte is a 0.05-0.5M sulfuric acid aqueous solution; the cathode electrolyte is a benzoic acid solution with a concentration of 40-80mM, and the solvent of the benzoic acid solution is a 0.1-1M alkali metal hydroxide aqueous solution; the contact area between the cathode and the cathode electrolyte is 2.5cm 2 ~4cm 2 ; electricity is applied to react to obtain cyclohexanecarboxylic acid; the alkali metal hydroxide is KOH or NaOH.
[0019] The contact area between the cathode and the cathode electrolyte is preferably 3 cm 2 .
[0020] The current of the power supply is 100-250mA, and the power supply time is 100min-240min.
[0021] Advantages of the present invention:
[0022] (1) The preparation method of the Ru single metal catalyst of the present invention is simple and reproducible.
[0023] (2) The Ru single metal catalyst of the present invention is used as the cathode in the application process of cyclohexanecarboxylic acid electrosynthesis. The catalyst is prepared from a single metal, is economical and environmentally friendly, greatly reduces the price of the catalyst, and has ultra-high cycle stability.
[0024] (3) The active components of the Ru single metal catalyst of the present invention are mainly distributed on the surface of the carbon cloth carrier, so that it can expose more active sites, generate sufficient active hydrogen, and improve the utilization rate of metal atoms. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 This is a scanning electron microscope image of the Ru single metal catalyst prepared in Example 1. DETAILED DESCRIPTION
[0026] The following examples are provided to enable those skilled in the art to better understand the present invention, but are not intended to limit the present invention in any way.
[0027] Example 1
[0028] A method for preparing a Ru single metal catalyst comprises the following steps:
[0029] 1) dissolving ruthenium chloride in a 0.5M sodium sulfate aqueous solution, stirring evenly, to obtain a ruthenium chloride solution as an electrolyte; the concentration of the ruthenium chloride solution is 5mM;
[0030] 2) Cut the carbon cloth into a large rectangular piece (3.5 cm × 2.5 cm × 0.1 cm) and a small rectangular piece (3 cm × 1.5 cm × 0.1 cm), use the large rectangular piece as the counter electrode, the small rectangular piece as the working electrode, and the Ag / AgCl electrode as the reference electrode, and place the counter electrode, the working electrode, and the reference electrode vertically from left to right in a single-cell electrolytic cell containing the electrolyte obtained in step 1), and set the counter electrode and the working electrode in parallel, and make the center of the counter electrode and the center of the working electrode on the same horizontal line, adopt cyclic voltammetry, set the scanning number to 100, the voltage range to -0.8 V to 1.1 V, and the scanning rate to 0.1 V / s for electroplating; after the electroplating is completed, take out the electroplated working electrode, wash it with water and anhydrous ethanol in turn, and dry it to obtain a Ru metal catalyst.
[0031] The morphology of the structure was obtained by scanning electron microscopy (see Figure 1 ).
[0032] The use of the above-mentioned Ru single metal catalyst in the electrosynthesis of cyclohexanecarboxylic acid comprises the following steps:
[0033] An H-type electrolytic cell was used, with an anolyte and an anode Pt sheet placed in the anode cell, and a cathode electrolyte and a cathode placed in the cathode cell. The cathode was the Ru single metal catalyst prepared in this embodiment, and the anolyte was a 0.05M sulfuric acid aqueous solution; the cathode electrolyte was a 50mM benzoic acid solution, and the solvent of the benzoic acid solution was a 0.1M KOH aqueous solution; the contact area between the cathode and the cathode electrolyte was 3cm 2 ; Power is applied, reaction is carried out, and cyclohexanecarboxylic acid is obtained; the current applied is 200 mA, and the power-on time is 150 min.
[0034] After the reaction is finished, 200 microliters of the liquid in the cathode tank are added with 200 microliters of 0.5M sulfuric acid aqueous solution, and then 200 microliters of ethyl acetate are added for extraction. The upper layer of liquid after extraction is taken for qualitative and quantitative detection by gas chromatograph to obtain the test results, and the Faraday efficiency and the selectivity of the product can be calculated. The product conversion rate of this embodiment reaches 99%, and the selectivity of cyclohexanecarboxylic acid is 99%.
[0035] Example 2
[0036] A method for preparing a Ru single metal catalyst comprises the following steps:
[0037] 1) dissolving ruthenium chloride in a 0.3M sodium sulfate aqueous solution, stirring evenly, to obtain a ruthenium chloride solution as an electrolyte; the concentration of the ruthenium chloride solution is 3mM;
[0038] 2) Cut the carbon cloth into a large rectangular piece (3.8 cm × 2.8 cm × 0.1 cm) and a small rectangular piece (3.2 cm × 1.5 cm × 0.1 cm), use the large rectangular piece as the counter electrode, the small rectangular piece as the working electrode, and the Ag / AgCl electrode as the reference electrode, and place the counter electrode, the working electrode, and the reference electrode vertically from left to right in a single-cell electrolytic cell containing the electrolyte obtained in step 1), and set the counter electrode and the working electrode in parallel, and make the center of the counter electrode and the center of the working electrode on the same horizontal line, adopt cyclic voltammetry, set the scanning number to 150, the voltage range to -0.9 to 1.2 V, and the scanning rate to 0.05 V / s for electroplating; after the electroplating is completed, take out the electroplated working electrode, wash it with water and anhydrous ethanol in turn, and dry it to obtain a Ru metal catalyst.
[0039] The use of the above-mentioned Ru single metal catalyst in the electrosynthesis of cyclohexanecarboxylic acid comprises the following steps:
[0040] An H-type electrolytic cell was used, with an anolyte and an anode Pt sheet placed in the anode cell, and a cathode electrolyte and a cathode placed in the cathode cell. The cathode was the Ru single metal catalyst prepared in this embodiment, and the anolyte was a 0.1 M sulfuric acid aqueous solution; the cathode electrolyte was a 50 mM benzoic acid solution, and the solvent of the benzoic acid solution was a 0.2 M KOH aqueous solution; the contact area between the cathode and the cathode electrolyte was 2.5 cm 2 ; Power is applied, reaction is carried out, and cyclohexanecarboxylic acid is obtained; the current applied is 200 mA, and the power-on time is 240 min.
[0041] After the reaction is finished, 200 microliters of the liquid in the cathode tank are added with 200 microliters of 0.5M sulfuric acid aqueous solution, and then 200 microliters of ethyl acetate are added for extraction. The upper layer of liquid after extraction is taken for qualitative and quantitative detection by gas chromatograph to obtain the test results, and the Faraday efficiency and the selectivity of the product can be calculated. The product conversion rate of this embodiment reaches 97%, and the selectivity of cyclohexanecarboxylic acid is 99%.
[0042] Example 3
[0043] A method for preparing a Ru single metal catalyst comprises the following steps:
[0044] 1) dissolving ruthenium chloride in a 0.8M sodium sulfate aqueous solution, stirring evenly, to obtain a ruthenium chloride solution as an electrolyte; the concentration of the ruthenium chloride solution is 7mM;
[0045] 2) Cut the carbon cloth into a large rectangular piece (4 cm × 3 cm × 0.1 cm) and a small rectangular piece (3.5 cm × 1.5 cm × 0.1 cm), use the large rectangular piece as the counter electrode, the small rectangular piece as the working electrode, and the Ag / AgCl electrode as the reference electrode, and place the counter electrode, the working electrode, and the reference electrode vertically from left to right in a single-cell electrolytic cell containing the electrolyte obtained in step 1), and set the counter electrode and the working electrode in parallel, and make the center of the counter electrode and the center of the working electrode on the same horizontal line, adopt cyclic voltammetry, set the scanning number of 200 circles, the voltage range of -0.8 V to 1.1 V, and the scanning rate of 0.2 V / s for electroplating; after the electroplating is completed, take out the electroplated working electrode, wash it with water and anhydrous ethanol in turn, and dry it to obtain a Ru metal catalyst.
[0046] The application of the above-mentioned Ru single metal catalyst in the electrosynthesis of cyclohexanecarboxylic acid comprises the following steps:
[0047] An H-type electrolytic cell was used, with an anolyte and an anode Pt sheet placed in the anode cell, and a cathode electrolyte and a cathode placed in the cathode cell. The cathode was the Ru single metal catalyst prepared in this embodiment, and the anolyte was a 0.5M sulfuric acid aqueous solution; the cathode electrolyte was a 40mM benzoic acid solution, and the solvent of the benzoic acid solution was a 1M NaOH aqueous solution; the contact area between the cathode and the cathode electrolyte was 4cm 2 ; Power is applied, reaction is carried out, and cyclohexanecarboxylic acid is obtained; the current applied is 100 mA, and the power-on time is 100 min.
[0048] After the reaction, 200 μl of the liquid in the cathode tank was added with 200 μl of 0.5M sulfuric acid aqueous solution, and then 200 μl of ethyl acetate was added for extraction. The upper layer of the extracted liquid was taken for qualitative and quantitative detection using a gas chromatograph to obtain:
[0049] 99% conversion of benzoic acid, 99% selectivity of cyclohexanecarboxylic acid.
[0050] Example 4
[0051] A method for preparing a Ru single metal catalyst comprises the following steps:
[0052] 1) dissolving ruthenium chloride in a 0.5M sodium sulfate aqueous solution, stirring evenly, to obtain a ruthenium chloride solution as an electrolyte; the concentration of the ruthenium chloride solution is 5mM;
[0053] 2) Cut the carbon cloth into a large rectangular piece (3.5 cm × 2.5 cm × 0.1 cm) and a small rectangular piece (3 cm × 1.5 cm × 0.1 cm), use the large rectangular piece as the counter electrode, the small rectangular piece as the working electrode, and the Ag / AgCl electrode as the reference electrode, and place the counter electrode, the working electrode, and the reference electrode vertically from left to right in a single-cell electrolytic cell containing the electrolyte obtained in step 1), and set the counter electrode and the working electrode in parallel, and make the center of the counter electrode and the center of the working electrode on the same horizontal line, adopt cyclic voltammetry, set the scanning number to 100, the voltage range to -0.8 V to 1.1 V, and the scanning rate to 0.1 V / s for electroplating; after the electroplating is completed, take out the electroplated working electrode, wash it with water and anhydrous ethanol in turn, and dry it to obtain a Ru metal catalyst.
[0054] The use of the above-mentioned Ru single metal catalyst in the electrosynthesis of cyclohexanecarboxylic acid comprises the following steps:
[0055] An H-type electrolytic cell was used, with an anolyte and an anode Pt sheet placed in the anode cell, and a cathode electrolyte and a cathode placed in the cathode cell. The cathode was the Ru single metal catalyst prepared in this embodiment, and the anolyte was a 0.05M sulfuric acid aqueous solution; the cathode electrolyte was a benzoic acid solution with a concentration of 80mM, and the solvent of the benzoic acid solution was a 0.1M KOH aqueous solution; the contact area between the cathode and the cathode electrolyte was 3cm 2 ; Power is applied, reaction is carried out, and cyclohexanecarboxylic acid is obtained; the current applied is 250 mA, and the power-on time is 240 min.
[0056] After the reaction, 200 μl of the liquid in the cathode tank was added with 200 μl of 0.5M sulfuric acid aqueous solution, and then 200 μl of ethyl acetate was added for extraction. The upper layer of the extracted liquid was taken for qualitative and quantitative detection using a gas chromatograph to obtain:
[0057] 99% conversion of benzoic acid, 99% selectivity of cyclohexanecarboxylic acid.
Claims
1. A method for preparing a Ru single metal catalyst, characterized in that The steps include: 1) dissolving ruthenium chloride in a sodium sulfate aqueous solution with a concentration of 0.3-0.8M, stirring evenly, and obtaining a ruthenium chloride solution as an electrolyte; 2) Cut the carbon cloth into a large rectangular piece and a small rectangular piece, use the large rectangular piece as the counter electrode, the small rectangular piece as the working electrode, and the Ag / AgCl electrode as the reference electrode. In a single-cell electrolytic cell containing the electrolyte obtained in step 1), vertically place the counter electrode, the working electrode, and the reference electrode from left to right, and set the counter electrode and the working electrode in parallel, so that the center of the counter electrode and the center of the working electrode are on the same horizontal line. Use cyclic voltammetry, set the scanning number to 100 to 200, the voltage range to -0.9V to 1.2V, and the scanning rate to 0.05-0.2V / s for electroplating; after the electroplating is completed, take out the electroplated working electrode, wash it with water and anhydrous ethanol in turn, and dry it to obtain a Ru single metal catalyst.
2. The method according to claim 1, characterized in that The concentration of the sodium sulfate aqueous solution is 0.5M.
3. The method according to claim 1 or 2, characterized in that The concentration of the ruthenium chloride solution in step 1) is 3-7 mM.
4. The method according to claim 1, characterized in that The size of the large rectangular piece is (3.5-4) cm×(2.5-3) cm×0.1 cm; the size of the small rectangular piece is (3-3.5) cm×1.5 cm×0.1 cm.
5. The method according to claim 1, characterized in that The voltage range is -0.8~1.1V.
6. A Ru single metal catalyst prepared by the method according to any one of claims 1 to 5.
7. Use of the Ru monometallic catalyst according to claim 6 in the electrosynthesis of cyclohexanecarboxylic acid.
8. The use according to claim 7, characterized in that The method comprises the following steps: using an H-type electrolytic cell, placing an anolyte and an anode Pt sheet in the anode cell, placing a cathode electrolyte and a cathode in the cathode cell, wherein the cathode is a Ru single metal catalyst, the anolyte is a 0.05-0.5M sulfuric acid aqueous solution; the cathode electrolyte is a benzoic acid solution with a concentration of 40-80mM, and the solvent of the benzoic acid solution is a 0.1-1M alkali metal hydroxide aqueous solution; the contact area between the cathode and the cathode electrolyte is 2.5cm 2 ~4cm 2 ; electricity is applied to react to obtain cyclohexanecarboxylic acid; the alkali metal hydroxide is KOH or NaOH.
9. The use according to claim 8, characterized in that The contact area between the cathode and the cathode electrolyte is 3 cm 2 .
10. The use according to claim 8, characterized in that The current of the power supply is 100-250 mA, and the power supply time is 100-240 minutes.