A method for the electrocatalytic hydrogenation of carbonyl compounds to synthesize the corresponding alcohols

Abstract

The present application relates to a kind of methods for synthesizing corresponding alcohol by electrocatalytic hydrogenation of carbonyl compound, using flow electrolytic cell or split H-type electrolytic cell, adding carbonyl compound in cathode electrolyte, collecting liquid phase alcohol product at reaction output end.The carbonyl compound includes formaldehyde, acetaldehyde, acetone, n-propyl aldehyde, n-butyl aldehyde, n-pentanal, 4-hydroxy-2-butanone, diacetone alcohol, 2-pentanone, cyclobutanone, furfural and other carbonyl-containing compounds.Different types of electrolytic cell are used, and the iron-based electrocatalyst constructed has the characteristics of low cost, high activity and high selectivity.Compared with traditional thermal catalytic technology, the electrocatalytic hydrogenation of carbonyl compound to synthesize corresponding alcohol technology is carried out at room temperature and normal pressure, using water as hydrogen source, which not only reduces energy consumption and production cost, but also is green, safe and efficient, in line with the requirements of green chemical industry.

Description

Technical Field

[0001] This invention pertains to a method for synthesizing corresponding alcohols by electrochemical hydrogenation of carbonyl compounds of chemical formula (I), and relates to a method for synthesizing corresponding alcohols by electrocatalytic hydrogenation of carbonyl compounds. Background Technology

[0002] Currently, alcohols have a wide range of applications in medicine and daily life. Compared to ethanol, isopropanol has a higher boiling point, lower volatility, is easier to store, and is safer and more reliable to use. Therefore, isopropanol is widely used in pharmaceuticals, cosmetics, plastics, fragrances, coatings, electronic cleaning agents, and other products. Among these, industrial cleaning agents are one of the fastest-growing sectors of global isopropanol consumption, with demand projected to grow at an average annual rate of >10%.

[0003] To date, methods for hydrogenating carbonyl compounds to produce the corresponding alcohols include chemical reduction and thermocatalytic hydrogenation. Chemical reduction uses reducing agents such as NaBH4, LiAlH4, and Al[OCH(CH3)2]3; thermocatalytic hydrogenation uses a catalyst with H2 as the hydrogen source, and the reduction is carried out under high temperature and pressure. Thermocatalytic hydrogenation of acetone to isopropanol typically uses noble metal catalysts such as Pd, Pt, and Ru, or non-noble metal catalysts such as nickel-based and copper-based catalysts.

[0004] Japanese Patent Hei 2-279643 discloses a method for the thermal catalytic hydrogenation of acetone to isopropanol using a Ru / Al2O3 catalyst. Acetone is diluted with isopropanol before hydrogenation, achieving a 99.9% conversion rate for acetone and a 99.9% selectivity for isopropanol at a pressure of 9.0 MPa. However, this method requires an expensive Ru-based catalyst and high-pressure hydrogen, resulting in demanding process conditions and equipment requirements.

[0005] Chinese patent CN1255482A provides a method for preparing isopropanol by hydrogenation of acetone using a tableted CuO-SiO composite oxide catalyst. At 140℃, both the acetone conversion rate and isopropanol selectivity can reach 99.9%. However, this method has key problems such as easy catalyst sintering and deactivation, and harsh process conditions.

[0006] In summary, current thermocatalytic hydrogenation processes for carbonyl compounds suffer from drawbacks such as the use of explosive high-pressure hydrogen as a hydrogen source, demanding reaction conditions, high equipment requirements, and expensive catalysts. Therefore, developing a method for the electrocatalytic hydrogenation of carbonyl compounds to prepare corresponding alcohols at ambient temperature and pressure using water as a hydrogen source is of great significance. Summary of the Invention

[0007] Technical problems to be solved

[0008] To avoid the shortcomings of existing technologies, this invention proposes a method for synthesizing corresponding alcohols by electrocatalytic hydrogenation of carbonyl compounds. Extensive and in-depth research has been conducted on the catalysts and device systems used in the electrocatalytic hydrogenation of carbonyl compounds to suppress side reactions and improve the yield of the corresponding alcohols. This method also has the advantages of being room temperature and atmospheric pressure, green, safe, and low cost.

[0009] Technical solution

[0010] A method for synthesizing corresponding alcohols by electrocatalytic hydrogenation of carbonyl compounds is characterized in that: in an electrolytic cell, water in an aqueous electrolyte is used as the hydrogen source, a carbonyl compound is added to the cathode electrolyte, and during the electrolysis reaction, the liquid phase collected at the output end is an alcohol product.

[0011] The structural formula of the carbonyl compound is:

[0012]

[0013] Where R and R' are selected from inorganic / or organic groups;

[0014] The inorganic and / or organic groups are selected from -H, -D, substituted or unsubstituted alkyl, alkenyl, alkynyl and / or aryl, -OH, -OR*, -SH, -SR*, -NH2, -NR*R # , -COOH, -CHO, -COOR*, -COR*, -PH2, -PR*R # -F, -Cl, -Br, -I, -NO, and -NO2, where R* and R # It can be an organic and / or inorganic group.

[0015] The carbonyl compounds include, but are not limited to, formaldehyde, acetaldehyde, acetone, n-propanal, n-butanal, n-pentanal, 4-hydroxy-2-butanone, diacetone alcohol, 2-pentanone, cyclobutanone, or furfural.

[0016] The electrolyte is a neutral, alkaline, or acidic electrolyte; that is, including but not limited to 0.01–10M KHCO3 aqueous solution, 0.01–5M KCl aqueous solution, or 0.01–10M KOH aqueous solution, or 0.01–10M H2SO4 aqueous solution.

[0017] When a flow electrolytic cell is used, the cathode is prepared by spraying catalyst A onto an ion exchange membrane, and the catalyst loading is 0.001–100 mg / cm³. 2 Alternatively, a working electrode can be prepared by spraying catalyst A onto a conductive substrate, with a catalyst loading of 0.001–100 mg / cm³. 2Alternatively, a catalyst grown in situ on a conductive substrate can be used as the cathode; the conductive substrate includes, but is not limited to, foamed metal, carbon paper, or carbon cloth; the foamed metal includes, but is not limited to, foamed copper, foamed nickel, or foamed iron; catalyst B is sprayed onto the anode; an electrolyte is added to the cathode and anode chambers, and a carbonyl compound is added to the cathode electrolyte; the electrocatalytic hydrogenation reaction of the carbonyl compound is carried out using a three-electrode or two-electrode system, and the liquid phase product is collected.

[0018] When the electrolytic cell is a split-type H-type electrolytic cell, the cathode is a working electrode made by spraying catalyst A onto a conductive substrate, and the catalyst loading after spraying is 0.001–100 mg / cm³. 2 Alternatively, a catalyst grown in situ on a conductive substrate can be used as the cathode; the conductive substrate includes, but is not limited to, foamed metal, carbon paper, or carbon cloth; the foamed metal includes, but is not limited to, foamed copper, foamed nickel, or foamed iron; catalyst B is sprayed onto the anode; an electrolyte is added to the cathode and anode chambers, and a carbonyl compound is added to the cathode electrolyte; the electrocatalytic hydrogenation reaction of the carbonyl compound is carried out using a three-electrode or two-electrode system, and the liquid phase product is collected.

[0019] Catalyst A includes, but is not limited to, Fe, Co, Ni, Cu, Ag, Au, Pd, Pt particles, alloys and their metal oxides, single-atom catalysts, and metal phthalocyanine or metal carbene type catalysts.

[0020] The powder of catalyst B includes, but is not limited to, Ir, Ru-based catalysts and Fe, Co, or Ni-based catalysts.

[0021] The catalyst A or B is prepared as follows: 1–1000 mg of catalyst A or B powder is dispersed in 0.2–200 mL of isopropanol or other dispersant, 3 μL–5 mL of Nafion solution is added as a binder, and the mixture is stirred and ultrasonically dispersed for 10–120 min to obtain a catalyst slurry; the concentration of the Nafion solution is 5 wt%.

[0022] When using in-situ generation of metal / metal oxide on foamed metal as a cathode, the preparation steps are as follows: First, the foamed metal is sequentially cleaned with acetone, ethanol, and 1M hydrochloric acid, and then dried with nitrogen; second, the temperature is increased by 2–10 °C / min in air, and annealed at 300–800 °C for 1–6 hours to uniformly grow metal oxide on the foamed metal; finally, the cathode is grown at a rate of 0.1–2 A / cm. 2 Constant current in-situ restoration.

[0023] Beneficial effects

[0024] This invention proposes a method for the electrocatalytic hydrogenation of carbonyl compounds to synthesize corresponding alcohols. The method employs a flow-through electrolytic cell or a split-type H-cell electrolytic cell. The carbonyl compound is added to the cathode electrolyte, and the liquid-phase alcohol product is collected at the reaction output. The carbonyl compound includes formaldehyde, acetaldehyde, acetone, n-propanal, n-butyraldehyde, n-pentanal, 4-hydroxy-2-butanone, diacetone alcohol, 2-pentanone, cyclobutanone, furfural, and other carbonyl-containing compounds. Different types of electrolytic cells are used, including flow-through electrolytic cells and split-type H-cell electrolytic cells. The flow-through electrolytic cell based on a membrane electrode assembly effectively reduces the contact resistance and mass transfer resistance between the electrocatalyst and the ion exchange membrane. The constructed iron-based electrocatalyst is characterized by low cost, high activity, and high selectivity. Experimental results show that by adjusting a suitable voltage range, the Faradaic efficiency of the target product alcohol reaches over 70%, and the byproduct hydrogen is easily separated from the product alcohol. Compared with traditional thermocatalytic technology, this electrocatalytic hydrogenation of carbonyl compounds to synthesize corresponding alcohols is carried out at room temperature and atmospheric pressure, using water as the hydrogen source. This not only reduces energy consumption and production costs, but is also green, safe, and efficient, meeting the requirements of green chemical industry.

[0025] Catalytic hydrogenation of carbonyl compounds is a fundamental technology for the production of bulk and fine chemicals. Current hydrogenation technologies are mainly divided into gas-phase and liquid-phase hydrogenation. Compared to gas-phase hydrogenation, liquid-phase hydrogenation can be carried out at lower temperatures, and the solvent can adsorb and remove coke formed on the catalyst surface, extending catalyst life. However, current liquid-phase hydrogenation is limited by the low hydrogen concentration in the solvent, resulting in lower catalyst activity and stability compared to gas-phase hydrogenation technology. This patent utilizes an electrocatalytic method, using water as a hydrogen source, to generate active hydrogen in situ, thereby improving the catalytic hydrogenation performance of carbonyl compounds in the liquid phase.

[0026] The positive effects of this invention are as follows:

[0027] (1) In the method described in this invention, the membrane electrode preparation process is used in the flow electrolysis cell to reduce the contact resistance between the catalyst and the proton exchange membrane, resulting in low impedance;

[0028] (2) In the method of the present invention, the carbonyl compound is electroreduced to an alcohol at room temperature and atmospheric pressure, thereby reducing energy consumption;

[0029] (3) In the method described in this invention, non-precious metals such as iron are used as catalysts to reduce costs;

[0030] (4) In the method described in this invention, water is used as the hydrogen source, which avoids the risk of using hydrogen gas as the hydrogen source and meets the requirements of green chemical industry. Attached Figure Description

[0031] Figure 1 Schematic diagram of a split-type H-cell electrolyzer

[0032] Figure 2 Schematic diagram of a flowing electrolyzer Detailed Implementation

[0033] The present invention will now be further described in conjunction with the embodiments and accompanying drawings:

[0034] A method for synthesizing corresponding alcohols by electrocatalytic hydrogenation of carbonyl compounds is characterized by using a flow electrolytic cell or a split H-type electrolytic cell, adding carbonyl compounds to the cathode electrolyte, and collecting liquid-phase alcohol products at the reaction output end.

[0035] The reactants are carbonyl compounds containing chemical formula (I).

[0036]

[0037] R and R' are selected from inorganic and / or organic groups.

[0038] The inorganic and / or organic groups are selected from -H, -D, substituted or unsubstituted alkyl, alkenyl, alkynyl and / or aryl, -OH, -OR*, -SH, -SR*, -NH2, -NR*R # , -COOH, -CHO, -COOR*, -COR*, -PH2, -PR*R # -F, -Cl, -Br, -I, -NO, and -NO2, where R* and R # It can be an organic and / or inorganic group.

[0039] The scheme for electrochemical hydrogenation of carbonyl compounds of chemical formula (I) is as follows:

[0040]

[0041] When using a flow electrolytic cell, the steps are as follows:

[0042] Step a1: Prepare a cathode by spraying catalyst A onto an ion exchange membrane. The catalyst loading is 0.001–100 mg / cm³. 2 Alternatively, a working electrode can be prepared by spraying catalyst A onto a conductive substrate, with a catalyst loading of 0.001–100 mg / cm³. 2 Alternatively, a catalyst grown in situ on a conductive substrate may be used as the cathode; the conductive substrate may include, but is not limited to, foamed metal, carbon paper or carbon cloth, etc.; the foamed metal may include, but is not limited to, foamed copper, foamed nickel or foamed iron, etc.

[0043] Catalyst B is sprayed onto the anode;

[0044] Step a2: Add electrolyte to the cathode and anode chambers, and add a carbonyl compound to the cathode electrolyte. Use a three-electrode or two-electrode system to carry out the electrocatalytic hydrogenation reaction of the carbonyl compound, and collect the liquid phase product.

[0045] When using a split-type H-cell electrolyzer, the steps are as follows:

[0046] Step b1: A working electrode is prepared by spraying catalyst A onto a conductive substrate. The catalyst loading after spraying is 0.001–100 mg / cm³. 2 Alternatively, a catalyst grown in situ on a conductive substrate may be used as the cathode; the conductive substrate may include, but is not limited to, foamed metal, carbon paper or carbon cloth, etc.; the foamed metal may include, but is not limited to, foamed copper, foamed nickel or foamed iron, etc.

[0047] Catalyst B is sprayed onto the anode;

[0048] Step b2: Add electrolyte to the cathode and anode chambers, and add a carbonyl compound to the cathode electrolyte. Perform the electrocatalytic hydrogenation reaction of the carbonyl compound using a three-electrode or two-electrode system, and collect the liquid-phase product.

[0049] All conductive substrates can be used in this invention. For example, the substrate may include at least one metal such as silver, gold, platinum, iron, cobalt, nickel, lead, titanium, copper, manganese, or chromium or alloys thereof such as stainless steel and / or at least one nonmetal such as carbon, Si, boron nitride (BN), doped diamond, etc., and / or at least one conductive oxide such as indium tin oxide (ITO), zinc aluminum oxide (AZO), or fluorinated tin oxide (FTO), and / or at least one polymer for preparing conductive polymer-based electrodes, such as polyacetylene, polyethoxythiophene, polyaniline, or polypyrrole.

[0050] When the cathode chamber is selected by spraying a catalyst onto foam metal as the cathode, an ion exchange membrane is installed between the anode and cathode for isolation.

[0051] When using foamed metal as the cathode, the preparation steps are as follows: First, the foamed metal is sequentially cleaned with acetone, ethanol, and 1M hydrochloric acid, and then dried with nitrogen. Second, the temperature is increased by 2–10 °C / min in air, and annealed at 300–800 °C for 1–6 hours to uniformly grow metal oxides on the foamed metal. Finally, the cathode is dried at 0.1–2 A / cm². 2 Constant current in-situ restoration.

[0052] The slurry of catalyst A or B is as follows: 1–1000 mg of catalyst A or B powder is dispersed in 0.2–200 mL of isopropanol dispersant, and 3 μL–5 mL of Nafion solution (5%) is added as a binder. The mixture is stirred and ultrasonically dispersed for 10–120 min to obtain the catalyst slurry.

[0053] The catalyst A powder includes, but is not limited to, Fe, Co, Ni, Cu, Ag, Au, Pd, Pt particles, alloys and their metal oxides, single-atom catalysts, metal phthalocyanines or metal carbenes, etc.

[0054] The electrolytes in the cathode electrolyte and anolyte are neutral, alkaline, or acidic electrolytes, including but not limited to 0.01–10M KHCO3 aqueous solution, 0.01–5M KCl aqueous solution, or 0.01–10M KOH aqueous solution, 0.01–10M H2SO4 aqueous solution, propylene carbonate (PC) / tetrabutylammonium perchlorate (TBAP) organic solution, PC and dimethyl ethylene glycol (DME) organic solvent, 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([Bmim][CF3SO3]) / propylene carbonate (PC) solution, etc.

[0055] According to the method of the present invention, water-soluble carbonyl compounds are preferred, such as acetaldehyde, acetone, etc. Examples of carbonyl compounds include formaldehyde, acetaldehyde, acetone, n-propanal, n-butyraldehyde, n-pentanal, 4-hydroxy-2-butanone, diacetone alcohol, 2-pentanone, cyclobutanone, and furfural.

[0056] According to the method of the present invention, water is used as a proton donor. Any conductive salt and / or ionic liquid can be used, and a mixture of water and an inert organic solvent (e.g., 1,4-dioxane) can also be used to improve the solubility of the reactants.

[0057] To achieve the above objectives, the following technical solution is adopted.

[0058] 1. Electrocatalytic hydrogenation of carbonyl compounds to prepare corresponding alcohols is carried out using a flow electrolytic cell.

[0059] First, the cathode catalyst is prepared using methods such as membrane electrode assembly, spraying onto a conductive substrate, or in-situ growth. Hg / HgO or Ag / AgCl (without a reference electrode for full-cell testing) is used as the reference electrode for the electrolytic cell, and an ion-exchange membrane separates the anode and cathode.

[0060] The catalyst for the working electrode includes, but is not limited to, particles such as Fe, Co, Ni, Cu, Ag, Au, Pd, and Pt, alloys and their single-atom catalysts, metal phthalocyanines, or carbene catalysts.

[0061] The preparation steps of the cathode catalyst in the membrane electrode method are as follows: First, a catalyst slurry is prepared by dispersing 1–1000 mg of catalyst powder in 0.2–200 mL of isopropanol dispersant and adding 3 μL–5 mL of Nafion solution (5%) as a binder. The mixture is stirred and ultrasonically dispersed for 10–120 min to obtain the catalyst slurry. Second, the anion exchange membrane is cut to the size of the electrode area and placed flat on a flat heating plate. Finally, the catalyst is uniformly sprayed onto the surface of the anion exchange membrane using a precision spraying device and placed in an oven at 80°C for 30 min.

[0062] The anion exchange membrane is placed on a flat heating plate and heated at a temperature of 50–100°C, preferably 70–90°C.

[0063] The cathode catalyst preparation steps of the growth method are as follows: First, the foamed metal is sequentially cleaned with acetone, ethanol, and 1M hydrochloric acid, and then dried with nitrogen. Second, the temperature is increased by 2–10 °C / min in air, and annealed at 300–800 °C for 1–6 hours to uniformly grow metal oxides on the foamed metal. Finally, the catalyst is grown at a rate of 0.1–2 A / cm². 2 Constant current in-situ reduction is performed. Next, a carbonyl compound is added to the cathode electrolyte, and electrochemical performance is tested using a three-electrode or two-electrode system. Finally, the liquid-phase product is collected and analyzed by chromatography. Compared with traditional thermocatalytic technology, this method can hydrogenate the reactant carbonyl compound to the corresponding alcohol at room temperature and pressure, without consuming hydrogen gas. Using water as the hydrogen source significantly reduces energy consumption and potential hazards, better meeting the requirements of green chemistry.

[0064] The electrolytes in the cathode electrolyte and anolyte are neutral, alkaline, or acidic electrolytes; that is, including but not limited to 0.01–10M KHCO3 aqueous solution, 0.01–5M KCl aqueous solution or 0.01–10M KOH aqueous solution, 0.01–10M H2SO4 aqueous solution, propylene carbonate (PC) / tetrabutylammonium perchlorate (TBAP) organic solution, PC and dimethyl ethylene glycol (DME) organic solvent, 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([Bmim][CF3SO3]) / propylene carbonate (PC) solution, etc.

[0065] The flow rate of the cathode electrolyte is 0.1–100 sccm, and the flow rate of the anolyte is 0.1–100 sccm.

[0066] The carbonyl compounds include, but are not limited to: formaldehyde, acetaldehyde, acetone, n-propanal, n-butanal, n-pentanal, 4-hydroxy-2-butanone, diacetone alcohol, 2-pentanone, cyclobutanone, furfural, etc.

[0067] 2. Electrocatalytic hydrogenation of carbonyl compounds to prepare corresponding alcohols is carried out using a split-type H-cell electrolytic cell.

[0068] First, the prepared catalyst slurry is sprayed onto a conductive substrate (foam metal, carbon paper, or carbon cloth, etc.) as the working electrode; the counter electrode of the electrolytic cell is a platinum sheet, carbon rod, oxygen-generating catalyst, or selective oxidation catalyst of organic matter, etc.; Hg / HgO or Ag / AgCl (no reference electrode for full cell testing) is used as the reference electrode of the electrolytic cell, and the two chambers are separated by an ion exchange membrane.

[0069] The split-type H-type electrolytic cell is divided into two chambers: a cathode and an anode. The products of anode oxidation do not affect the products of cathode reduction.

[0070] The distance between the reference electrode and the working electrode in the split H-type electrolytic cell is fixed, and the area of ​​the counter electrode should be more than 1 times the area of ​​the working electrode.

[0071] Secondly, electrolyte is added to the cathode and anode chambers, and a carbonyl compound is added to the cathode chamber. Electrochemical performance is tested using a three-electrode or two-electrode system. Finally, the liquid-phase product is collected and analyzed. Simultaneously, the mass transfer rate of electrocatalytic hydrogenation can also be adjusted.

[0072] The electrolytes in the cathode electrolyte and anolyte are neutral, alkaline, or acidic electrolytes; that is, including but not limited to 0.01–10M KHCO3 aqueous solution, 0.01–5M KCl aqueous solution or 0.01–10M KOH aqueous solution, 0.01–10M H2SO4 aqueous solution, propylene carbonate (PC) / tetrabutylammonium perchlorate (TBAP) organic solution, PC and dimethyl ethylene glycol (DME) organic solvent, 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([Bmim][CF3SO3]) / propylene carbonate (PC) solution, etc.

[0073] The process involves adjusting the rotation speed of the cathode stirrer to reduce the accumulation of bubbles on the catalyst surface and control the hydrogenation mass transfer rate of carbonyl compounds.

[0074] The carbonyl compounds include, but are not limited to, formaldehyde, acetaldehyde, acetone, n-propanal, n-butanal, n-pentanal, 4-hydroxy-2-butanone, diacetone alcohol, 2-pentanone, cyclobutanone, furfural, etc. The invention is further illustrated below through specific embodiments. Unless otherwise specified, all raw materials are available from publicly available commercial sources.

[0075] The steps for the electrocatalytic hydrogenation of carbonyl compounds to prepare corresponding alcohols are as follows:

[0076]

Example 1

[0077] (1) Pretreatment of nickel foam: The nickel foam was immersed in 1M hydrochloric acid, acetone and ethanol for 5-10 min and ultrasonically cleaned, and then dried with nitrogen.

[0078] (2) The cleaned nickel foam was used as the cathode of the electrolytic cell, the Pt sheet as the anode, and Hg / HgO as the reference electrode. Both the cathode electrolyte and the anode electrolyte were 1M KOH solutions, separated by an anion exchange membrane. 5 mL of acetone was added to the cathode electrolyte.

[0079] (3) A split-type H-type electrolytic cell with a three-electrode system was used, and the electrochemical performance was tested using an electrochemical workstation. The catalytic activity of the nickel foam catalyst was characterized by potentiostatic method. The reaction was carried out for 1 hour, and the liquid product isopropanol was analyzed by chromatography.

[0080]

Example 2

[0081] (1) Preparation of Fe2O3 nanoparticle catalyst slurry: 10 mg of Fe2O3 nanoparticle catalyst powder was dispersed in 6 mL of isopropanol, and then 50 μL of Nafion solution (5%) was added. The mixture was stirred and ultrasonically dispersed for 90 min.

[0082] (2) Fe2O3 nanoparticle slurry was uniformly sprayed onto hydrophilic carbon paper to serve as the cathode of the electrolytic cell, and nickel foam was used as the anode. Both the cathode electrolyte and the anode electrolyte were 1M KOH solutions, separated by an anion exchange membrane. 5 mL of furfural was added to the cathode electrolyte.

[0083] (3) A three-electrode flow electrolytic cell was used, and the electrochemical performance was tested using an electrochemical workstation. The catalytic activity of the Fe2O3 nanoparticle catalyst was characterized by potentiostatic method. The reaction was carried out for 1 hour, and the liquid product furfuryl alcohol was analyzed by chromatography.

[0084]

Example 3

[0085] (1) Preparation of Fe2O3 nanoparticle catalyst slurry: 10 mg of Fe2O3 nanoparticle catalyst powder was dispersed in 6 mL of isopropanol, and then 50 μL of Nafion solution (5%) was added. The mixture was stirred and ultrasonically dispersed for 90 min.

[0086] (2) Fe2O3 nanoparticle slurry was uniformly sprayed onto the surface of an anion exchange membrane using a precision spraying device to serve as the cathode of the electrolytic cell. Nickel foam was used as the anode of the electrolytic cell. Both the cathode electrolyte and the anode electrolyte were 1M KOH solutions, separated by an anion exchange membrane. 5 mL of acetaldehyde was added to the cathode electrolyte.

[0087] (3) A flow electrolytic cell with a two-electrode system was used, and the electrochemical performance was tested using an electrochemical workstation. The catalytic activity of the Fe2O3 nanoparticle catalyst was characterized by potentiostatic method. The reaction was carried out for 1 hour, and the liquid product ethanol was analyzed by chromatography.

[0088]

Example 4

[0089] (1) Preparation of phthalocyanine iron nanoparticle catalyst slurry: 10 mg of phthalocyanine iron nanoparticle catalyst powder was dispersed in 6 mL of isopropanol, and then 50 μL of Nafion solution (5%) was added. The mixture was stirred and ultrasonically dispersed for 90 min.

[0090] (2) Phthalocyanine iron nanoparticle slurry was uniformly sprayed onto hydrophilic carbon paper to serve as the cathode of the electrolytic cell, and nickel foam was used as the anode. Both the cathode electrolyte and the anode electrolyte were 1M KOH solutions, separated by an anion exchange membrane. 5 mL of n-propanal was added to the cathode electrolyte.

[0091] (3) A flow electrolytic cell with a two-electrode system was used, and the electrochemical performance was tested using an electrochemical workstation. The catalytic activity of the catalyst iron phthalocyanine nanoparticles was characterized by potentiostatic method. The reaction was carried out for 1 hour, and the liquid product n-propanol was analyzed by chromatography.

[0092]

Example 5

[0093] (1) Preparation of electrodeposition copper catalyst: Prepare electrodeposition solution; use a three-electrode system of an electrolytic cell to uniformly electrodeposit copper on the hydrophobic surface of carbon paper by constant current method of electrochemical workstation.

[0094] (2) Electrodeposited copper catalyst was used as the cathode of the electrolytic cell, and nickel foam was used as the anode. Both the cathode electrolyte and the anode electrolyte were 1M KHCO3 solutions, separated by an anion exchange membrane. 5 mL of n-butyraldehyde was added to the cathode electrolyte.

[0095] (3) A flow electrolytic cell with a two-electrode system was used, and the electrochemical performance was tested using an electrochemical workstation. The catalytic activity of the catalyst iron phthalocyanine nanoparticles was characterized by potentiostatic method. The reaction was carried out for 1 hour, and the liquid product n-butanol was analyzed by chromatography.

[0096]

Example 6

[0097] (1) Preparation of CuAg nanoparticle catalyst slurry: Disperse 10 mg of CuAg nanoparticle catalyst powder in 6 mL of isopropanol, then add 50 μL of Nafion solution (5%), stir and ultrasonically disperse for 90 min.

[0098] (2) CuAg nanoparticle slurry was uniformly sprayed onto the surface of an anion exchange membrane using a precision spraying device to serve as the cathode of the electrolytic cell, and nickel foam was used as the anode. Both the cathode electrolyte and the anode electrolyte were 1M KOH solutions, separated by an anion exchange membrane. 5 mL of n-pentanal was added to the cathode electrolyte.

[0099] (3) A flow electrolytic cell with a two-electrode system was used, and the electrochemical performance was tested using an electrochemical workstation. The catalytic activity of the CuAg nanoparticle catalyst was characterized by potentiostatic method. The reaction was carried out for 1 hour, and the liquid product n-pentanol was analyzed by chromatography.

[0100]

Example 7

[0101] (1) Preparation of Fe3O4 nanoparticle catalyst slurry: 10 mg of Fe3O4 nanoparticle catalyst powder was dispersed in 6 mL of isopropanol, and then 50 μL of Nafion solution (5%) was added. The mixture was stirred and ultrasonically dispersed for 90 min.

[0102] (2) Fe3O4 nanoparticle slurry was uniformly sprayed onto the surface of an anion exchange membrane using a precision spraying device to serve as the cathode of the electrolytic cell, and nickel foam was used as the anode. Both the cathode electrolyte and the anode electrolyte were 1M KOH solutions, separated by an anion exchange membrane. 5 mL of 4-hydroxy-2-butanone was added to the cathode electrolyte.

[0103] (3) A flow electrolytic cell with a two-electrode system was used, and the electrochemical performance was tested using an electrochemical workstation. The catalytic activity of the Fe3O4 nanoparticle catalyst was characterized by potentiostatic method. The reaction was carried out for 1 hour, and the liquid product 1,3-butanediol was analyzed by chromatography.

[0104]

Example 8

[0105] (1) Preparation of foamed iron-based growth iron oxide catalyst: a. Clean the foamed iron by ultrasonic cleaning with acetone, ethanol and 1M hydrochloric acid for 5-10 min respectively, and dry with nitrogen; b. Grow iron oxide on the foamed iron by heating at 2℃ / min in air and annealing at 300-600℃ for 1-6 hours to uniformly grow metal oxide on the foamed metal.

[0106] (2) The Fe2O3 / Fe foam catalyst was used as the cathode of the electrolytic cell, and nickel foam was used as the anode. Both the cathode electrolyte and the anode electrolyte were 1M KOH solutions, separated by an anion exchange membrane. 5 mL of diacetone alcohol was added to the cathode electrolyte.

[0107] (3) A flow electrolytic cell with a two-electrode system was used, and the electrochemical performance was tested using an electrochemical workstation. The catalytic activity of the catalyst Fe2O3 / Fe foam was characterized by potentiostatic method. The reaction was carried out for 1 hour, and the liquid product 2-methyl-2,4-pentanediol was analyzed by chromatography.

[0108]

Example 9

[0109] (1) Pretreatment of foamed iron: Soak in 1M hydrochloric acid, acetone and ethanol for 5-10 min with ultrasonic cleaning, and dry with nitrogen.

[0110] (2) The cleaned foamed iron was used as the cathode of the electrolytic cell, and the Pt sheet was used as the anode. Both the cathode electrolyte and the anode electrolyte were 1M KCl solutions, separated by an anion exchange membrane. 5 mL of 2-pentanone was added to the cathode electrolyte.

[0111] (3) A two-electrode flow electrolytic cell was used, and the electrochemical performance was tested using an electrochemical workstation. The catalytic activity of the foamed iron catalyst was characterized by potentiostatic method. The reaction was carried out for 1 hour, and the liquid product 2-pentanol was analyzed by chromatography.

[0112]

Example 10

[0113] (1) Preparation of Fe2O3 nanoparticle catalyst slurry: 10 mg of Fe2O3 nanoparticle catalyst powder was dispersed in 6 mL of isopropanol, and then 50 μL of Nafion solution (5%) was added. The mixture was stirred and ultrasonically dispersed for 90 min.

[0114] (2) Fe2O3 nanoparticle catalyst was used as the cathode of the electrolytic cell, and nickel foam was used as the anode. Both the cathode electrolyte and the anode electrolyte were 1M propylene carbonate (PC) / tetrabutylammonium perchlorate (TBAP) organic solutions, separated by an anion exchange membrane. 5 mL of cyclobutanone was added to the cathode electrolyte.

[0115] (3) A two-electrode flow electrolytic cell was used, and the electrochemical performance was tested using an electrochemical workstation. The catalytic activity of the Fe2O3 nanoparticle catalyst was characterized by potentiostatic method. The reaction was carried out for 1 hour, and the liquid products cyclobutanol and n-propanol were analyzed by chromatography.

[0116] In summary, this invention uses mild and inexpensive water as a hydrogen source to replace expensive hydrogen gas or organic hydrogen carriers, solving the practical problems of existing hydrogenation methods for preparing corresponding alcohols from carbonyl compounds, such as the use of expensive reducing agents, complex preparation processes, and harsh reaction conditions. By utilizing the excellent adsorption and activation capabilities of the catalyst for carbonyl groups, an efficiency >1.5 A / cm² is achieved. 2 The high partial current density and selectivity (>99%) reduce reaction costs and ensure safe production. Furthermore, it offers broader substrate applicability, enabling the preparation of a variety of alcohol compounds.

[0117]

[0118] In summary, the above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any improvements or modifications made based on the above description should fall within the scope of protection of the appended claims.

Claims

1. A method for the electrocatalytic hydrogenation of a carbonyl compound to synthesize the corresponding alcohol, characterized in that: In an electrolytic cell, water in an aqueous electrolyte is used as the hydrogen source. A carbonyl compound is added to the cathode electrolyte. When an electrolysis reaction is carried out by energizing, the liquid phase collected at the output end is an alcohol product. A foam-based iron oxide growth catalyst was prepared, and the prepared Fe2O3 / Fe foam was used as the cathode of an electrolytic cell. The structural formula of the carbonyl compound is: R and R' are selected from -H, -D, substituted or unsubstituted alkyl groups and / or -OH.

2. The method of electrocatalytic hydrogenation of a carbonyl compound to synthesize the corresponding alcohol according to claim 1, characterized in that: The carbonyl compounds include formaldehyde, acetaldehyde, acetone, n-propanal, n-butanal, n-pentanal, 4-hydroxy-2-butanone, diacetone alcohol, 2-pentanone, cyclobutanone, or furfural.

3. The method for synthesizing the corresponding alcohol by electrocatalytic hydrogenation of carbonyl compounds according to claim 1, characterized in that: The electrolyte is a 0.01–10 M aqueous solution of KHCO3, a 0.01–5 M aqueous solution of KCl, or a 0.01–10 M aqueous solution of KOH.

4. The method of electrocatalytic hydrogenation of a carbonyl compound to synthesize a corresponding alcohol according to claim 1, characterized in that: When the electrolytic cell is a flow electrolytic cell or a split H-type electrolytic cell, the catalyst grown in situ on the conductive substrate is used as the cathode; catalyst B is sprayed onto the anode; electrolyte is added to the cathode and anode chambers, and a carbonyl compound is added to the cathode electrolyte; the electrocatalytic hydrogenation reaction of the carbonyl compound is carried out using a three-electrode or two-electrode system, and the liquid phase product is collected.

5. The method of electrocatalytic hydrogenation of a carbonyl compound to synthesize a corresponding alcohol according to claim 4, characterized in that: The powder of catalyst B includes Ir, Ru-based catalysts and Fe, Co, or Ni-based catalysts.

6. The method of electrocatalytic hydrogenation of a carbonyl compound to synthesize a corresponding alcohol according to claim 4, characterized in that: The catalyst B is prepared as follows: 1–1000 mg of catalyst B powder is dispersed in 0.2–200 mL of isopropanol or other dispersant, 3 μL–5 mL of Nafion solution is added as a binder, and the mixture is stirred and ultrasonically dispersed for 10–120 min to obtain a catalyst slurry; the concentration of the Nafion solution is 5 wt%.

7. The method of electrocatalytic hydrogenation of a carbonyl compound to synthesize a corresponding alcohol according to claim 4, characterized in that: When using in-situ growth of metal oxides on foamed metal as the cathode, the cathode preparation steps are as follows: First, the foamed metal is sequentially cleaned with acetone, ethanol, and 1 M hydrochloric acid, and then dried with nitrogen; second, the temperature is increased by 2–10 °C / min in air, and annealed at 300–800 °C for 1–6 hours to uniformly grow the metal oxide on the foamed metal; finally, the cathode is dried at 0.1–2 A / cm². 2 Constant current in-situ restoration.

Images