Nickel alloy-organic framework electrocatalyst and its preparation method and application

Abstract

The present invention discloses a nickel alloy-organic framework electrocatalyst, a preparation method thereof and an application thereof. The nickel alloy-organic framework electrocatalyst is prepared by a solvothermal method and is applied to the electrolytic preparation of 19-formyl-4-androstene-3,17-dione. During electrolysis, 19-hydroxy-4-androstene-3,17-dione, an alkaline solution, an organic solvent and a nitroxide radical are used as the anolyte, and the alkaline solution is used as the catholyte, and a continuous flow electrolytic cell is used for the reaction. Compared with the chromium process commonly used in the prior art, the electrocatalytic oxidation reaction process adopted by the present invention has mild conditions, is green and pollution-free, has a high raw material conversion rate, good selectivity for 19-formyl-4-androstene-3,17-dione, and a high Faraday efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of the synthesis of organic chemical products, and particularly relates to a nickel alloy-organic framework electrocatalyst, a preparation method thereof, and an application thereof. Background Art

[0002] Hormones generally include sex hormones, thyroid hormones, steroid hormones, and insulin. Steroid hormones are an important class among them. Also known as steroid hormones, they are a class of tetracyclic aliphatic hydrocarbon compounds and have extremely important medical value. They play a clear role in maintaining life, regulating sexual function, and in aspects such as the development of the body, immune regulation, treatment of skin diseases, and birth control. In the synthesis process of steroid hormone drugs, the conversion of alcohol to aldehyde or carbonyl is a very important oxidation reaction, such as the reaction of oxidizing 19-hydroxy-4-androstene-3,17-dione to 19-formyl-4-androstene-3,17-dione. Currently, heavy metal chromium oxidants are used for sterol oxidation. The chromium oxidation process has problems such as poor oxidation selectivity, environmental pollution by heavy metal chromium, and difficulty in treating chromium slag. Currently, 2,2,6,6-tetramethylpiperidine-N-oxide (TEMPO) is also used as a catalyst, and sodium hypochlorite is used as an oxidant to selectively oxidize alcohol (patent numbers are 200580040795.8 and 200680026352.8 respectively). However, these synthesis methods all use chemical oxidants, and the oxidation reaction is slow and time-consuming. Summary of the Invention

[0003] Aiming at the problems brought by the current process, the purpose of the present invention is to provide a nickel alloy-organic framework electrocatalyst, a preparation method thereof, and an application thereof.

[0004] The specific technical solutions are as follows:

[0005] A preparation method of a nickel alloy-organic framework electrocatalyst includes the following steps:

[0006] 1) Dissolve nickel nitrate, non-precious metal salt A, and terephthalic acid in DMF, then add ethanol, and ultrasonically disperse the solution to obtain solution A. The non-precious metal salt A is selected from ferric nitrate, cobalt nitrate, copper nitrate, manganese nitrate, or zinc nitrate;

[0007] 2) Add solution A to a hydrothermal reactor, then add carbon felt, react at 80 - 180 °C for 6 - 24 hours, cool to room temperature after the reaction, take out the carbon felt after loading, wash it alternately with distilled water and ethanol, and then dry it in a blast drying oven at 40 - 100 °C for 6 - 18 hours to obtain a supported nickel alloy-organic framework electrocatalyst.

[0008] Further, the mass ratio of nickel nitrate, non-noble metal salt A and terephthalic acid is 1-6:1.5-9:1.5-4. A nickel alloy-organic framework electrocatalyst prepared by the above preparation method.

[0009] An application of a nickel alloy-organic framework electrocatalyst in the oxidation to prepare 19-formyl-4-androstene-3,17-dione. The specific implementation method is as follows: Use an electrochemical workstation to control the reaction current. Take the carbon felt loaded with the nickel alloy-organic framework electrocatalyst as the working electrode, and use a continuous flow electrolytic cell for the reaction. The anode chamber and the cathode chamber are separated by a proton exchange membrane. After ultrasonic dissolution of 19-hydroxy-4-androstene-3,17-dione, an alkaline solution, an organic solvent and a nitroxide free radical, place it in a constant temperature water bath and stir it as the anolyte; use the alkaline solution as the catholyte. Continuously pump the anolyte and the catholyte into the anode chamber and the cathode chamber respectively through a peristaltic pump. Set the reaction temperature to 30-60 °C and the current density to 10-200 mA / cm 2 , the anode voltage is 0.6-1.0 V. Under this test condition, perform electrocatalytic selective oxidation. When there is no reactant signal detected by HPLC, end the reaction and add an organic solvent for extraction to obtain an organic extract. Take the organic layer and perform rotary evaporation to obtain 19-formyl-4-androstene-3,17-dione.

[0010] The anodic reaction equation is as follows:

[0011] .

[0012] Further, the concentration of 19-hydroxy-4-androstene-3,17-dione in the anolyte is 50-200 mmol / L.

[0013] Further, the flow rate of the continuous flow electrolytic cell is 40-200 mL / min, preferably 120 mL / min.

[0014] Further, the alkaline solution added to the anolyte is sodium carbonate solution, sodium bicarbonate solution or sodium hydroxide solution, preferably sodium carbonate solution. The concentration of the alkaline solution is 0.5-2.0 mol / L. The organic solvent is one of tetrahydrofuran, dichloromethane, acetonitrile and acetone. The alkaline solution in the catholyte is sodium carbonate solution.

[0015] Further, the nitroxide free radical added to the anolyte is TEMPO, 4-amino-TEMPO, ACT, 4-Cl-acetamido-TEMPO or 4-oxo-TEMPO. The concentration of the nitroxide free radical in the anolyte is 0.5-15 mmol / L.

[0016] Further, the volume ratio of the alkaline solution and the organic solvent fed into the anolyte is 1:4-4:1

[0017] Furthermore, the organic solvent used for extraction is toluene, dichloromethane, chloroform, ethyl acetate or petroleum ether.

[0018] By adopting the above technologies, compared with the existing production process of 19-aldehyde-4-androstene-3,17-dione, the beneficial effects of the present invention are as follows:

[0019] 1) The present invention conducts selective oxidation electrochemically, which can avoid the use of Cr metal in traditional chemistry, thereby reducing the emission of polluting substances and being beneficial to sustainable development;

[0020] 2) The present invention obtains a nickel alloy-organic framework catalyst through a solvothermal reaction. This catalyst is simple to prepare, the raw materials are common and easy to obtain, and it has extremely strong stability. It has a great space-time yield in the reaction and has good development prospects. By adopting a continuous flow electrolytic cell, the influence of concentration polarization is reduced and the mass transfer driving force is increased;

[0021] 3) The organic framework catalyst used in the present invention has a unique pore structure, a relatively high specific surface area, and the diversity of central metal ion selection. It can be used as a promising electrode material for electrocatalytic alcohol oxidation reactions; and other metal elements such as Fe, Co, Zn, Mn, and Cu greatly promote the transformation of nickel hydroxide into nickel oxyhydroxide, increasing the reaction rate;

[0022] 4) After the nickel alloy-organic framework catalyst used in the present invention is combined with ACT, the oxidation current of the substrate 19-hydroxy-4-androstene-3,17-dione can reach 1 A, the reaction time is shortened to 2000 s, and the space-time yield is 16 kg / (m 3 ·h). Compared with the batch reactor, the reaction time is greatly reduced, the cost is reduced, and the energy consumption is reduced. Description of the Drawings

[0023] Figure 1a SEM image of the NiFe-MOF / GF electrode material of Example 1 at 200 nm;

[0024] Figure 1b SEM image of the NiFe-MOF / GF electrode material of Example 1 at 1 μm;

[0025] Figure 2a Graph showing the change of the reaction for preparing 19-aldehyde-4-androstene-3,17-dione by electrocatalytic oxidation of 19-hydroxy-4-androstene-3,17-dione in Example 1 with time;

[0026] Figure 2b Stability test graph for preparing 19-aldehyde-4-androstene-3,17-dione by electrocatalytic oxidation of 19-hydroxy-4-androstene-3,17-dione in Example 1. Detailed implementation manners

[0027] The technical solutions of the present invention will be further specifically described below through specific embodiments in conjunction with the accompanying drawings.

[0028] Example 1: Synthesis of NiFe-MOF / GF and its electrocatalytic oxidation of 19-hydroxy-4-androstene-3,17-dione to prepare 19-formyl-4-androstene-3,17-dione

[0029] (1) Weigh 145.5 mg of nickel nitrate, 606 mg of iron nitrate and 265.6 mg of terephthalic acid respectively and dissolve them in 40 mL of DMF and 20 mL of ethanol, and ultrasonically disperse for 20 minutes at room temperature to obtain solution A;

[0030] (2) Add the solution A in step (1) and the carbon felt carrier into a hydrothermal reactor, carry out hydrothermal reaction at 150 °C for 12 hours, then cool to room temperature, take out the carbon felt, wash it 3 times alternately with distilled water and ethanol, and dry it at 70 °C to obtain a carbon felt loaded with a nickel alloy-organic framework electrocatalyst, marked as NiFe-MOF / GF. Its SEM scanning electron micrograph is as shown in Figure 1a and 1b shown. It can be found from Figure 1a , Figure 1b that the nickel alloy-organic framework electrocatalyst has a nanosheet structure and is uniformly loaded on the carbon felt.

[0031] Test the catalytic performance of the nickel alloy-organic framework electrocatalyst prepared in Example 1. The specific method is as follows:

[0032] Cut NiFe-MOF / GF into about 3×3 cm 2 in size and directly use it as the working electrode. The current is controlled by an electrochemical workstation, and the reaction solution is continuously pumped into a continuous flow electrolytic cell by a peristaltic pump. The volumes of the anode chamber and the cathode chamber are 250 mL and are separated by a proton exchange membrane. 40 mL of 1M sodium carbonate solution and 60 mL of MeCN (organic solvent: sodium carbonate = 4:6) are used as the anode chamber electrolyte; 100 mL of 1M sodium carbonate solution is used as the cathode chamber electrolyte; ACT is added to the anode chamber as a medium for the oxidation reaction; in the cathode chamber of the electrolytic cell, nickel foam is used as the counter electrode for the hydrogen evolution reaction;

[0033] S1: Use 19-hydroxy-4-androstene-3,17-dione as the reactant, take 3 g of 19-hydroxy-4-androstene-3,17-dione and 213 mg of ACT and add them to the anode chamber electrolytic solution;

[0034] S2: Place the whole electrolytic cell in a constant temperature water bath to control the reaction system temperature at 30 °C, stir, and control the current density at 100 mA / cm 2, the voltage control range is 0.6 - 1.0V, the flow rate of the electrolytic cell is 120 mL / min, and the electrolysis reaction is carried out. The changes in the concentrations of reactants and products over time are shown in Figure 2a;

[0035] S3: After cooling the electrolytic solution in the anode chamber in step S2 to room temperature, it is extracted and layered with dichloromethane, and the dichloromethane phase is evaporated and separated to obtain the crude product of 19-aldehyde-4-androstene-3,17-dione. Tracking by HPLC shows that when the reaction reaches 33 minutes, the raw material conversion rate is 99%, and the selectivity of 19-aldehyde-4-androstene-3,17-dione is 99%.

[0036] S4: After washing alternately with distilled water and ethanol 3 times, it is dried at 70°C, and then the above performance tests are carried out. After repeating several times and obtaining its conversion rate and selectivity, the stability of the catalyst is finally obtained. The changes in its conversion rate and selectivity are shown in Figure 2b, and it can be obtained that the conversion rate and selectivity of the catalyst basically remain unchanged, both greater than 95%.

[0037] Example 2: Synthesis of NiMn-MOF / GF and its electrocatalytic oxidation of 19-hydroxy-4-androstene-3,17-dione to prepare 19-aldehyde-4-androstene-3,17-dione

[0038] (1) Weigh 145.5 mg of nickel nitrate, 287 mg of manganese nitrate, and 265.6 mg of terephthalic acid and dissolve them in 40 mL of DMF and 20 mL of ethanol, and ultrasonically disperse them at room temperature for 20 minutes to obtain solution A;

[0039] (2) Add solution A in step (1) and the carbon felt carrier into a hydrothermal reactor, carry out hydrothermal reaction at 150°C for 12 hours, then cool to room temperature, take out the carbon felt, wash it alternately with distilled water and ethanol 3 times, and dry it at 70°C to obtain the carbon felt loaded with the nickel alloy-organic framework electrocatalyst, marked as NiMn-MOF / GF.

[0040] The catalytic performance of the nickel alloy-organic framework electrocatalyst prepared in Example 2 was tested. The specific method is as follows:

[0041] Cut NiMn-MOF / GF to about 3×3 cm 2 in size and directly use it as the working electrode. The current is controlled by an electrochemical workstation, and a peristaltic pump continuously pumps the reaction solution into a continuous flow electrolytic cell. The volumes of the anode chamber and the cathode chamber are 250 mL and are separated by a proton exchange membrane. 50 mL of 1M sodium carbonate solution and 50 mL of MeCN (organic solvent: sodium carbonate = 5:5) are used as the anode chamber electrolyte; 100 mL of 1M sodium carbonate solution is used as the cathode chamber electrolyte; TEMPO is added to the anode chamber as a medium for the oxidation reaction; in the cathode chamber of the electrolytic cell, nickel foam is used as the counter electrode for the hydrogen evolution reaction;

[0042] S1: Using 19-hydroxy-4-androstene-3,17-dione as a reactant, 3 g of 19-hydroxy-4-androstene-3,17-dione and 156 mg of TEMPO are added to the electrolytic solution in the anodic chamber;

[0043] S2: The entire electrolytic cell is placed in a constant temperature water bath to control the reaction system temperature at 30 °C, stirred, the current density is controlled at 100 mA / cm 2 , the voltage is controlled in the range of 0.6 - 1.0 V, and the flow rate of the electrolytic cell is 120 mL / min for electrolysis reaction;

[0044] S3: After cooling the electrolytic solution in the anodic chamber in step S2 to room temperature, it is extracted and layered with dichloromethane, and the dichloromethane phase is evaporated and separated to obtain a crude product of 19-formyl-4-androstene-3,17-dione. Tracking by HPLC shows that when the reaction reaches 33 minutes, the raw material conversion rate is 90%, and the selectivity of 19-formyl-4-androstene-3,17-dione is 91%.

[0045] Example 3: Synthesis of NiCo-MOF / GF and its electrocatalytic oxidation of 19-hydroxy-4-androstene-3,17-dione to prepare 19-formyl-4-androstene-3,17-dione

[0046] (1) Weigh 145.5 mg of nickel nitrate, 436.5 mg of cobalt nitrate and 265.6 mg of terephthalic acid and dissolve them in 40 mL of DMF and 20 mL of ethanol, and ultrasonically disperse for 20 minutes at room temperature to obtain solution A;

[0047] (2) Add the solution A in step (1) and the carbon felt support to a hydrothermal autoclave, carry out hydrothermal reaction at 180 °C for 12 hours, then cool to room temperature, take out the carbon felt, wash it 3 times alternately with distilled water and ethanol, and dry it at 70 °C to obtain a carbon felt loaded with a nickel alloy-organic framework electrocatalyst, labeled as NiCo-MOF / GF.

[0048] The catalytic performance of the nickel alloy-organic framework electrocatalyst prepared in Example 3 was tested, and the specific method is as follows:

[0049] Cut the NiCo-MOF / GF to about 3×3 cm 2The size is directly used as the working electrode. The current is controlled by an electrochemical workstation, and a peristaltic pump continuously pumps the reaction solution into a continuous-flow electrolytic cell. The anode chamber and the cathode chamber have a volume of 250 mL and are separated by a proton exchange membrane. 70 mL of 1 M sodium carbonate solution and 30 mL of MeCN (organic solvent: sodium carbonate = 3:7) are used as the anode chamber electrolyte; 100 mL of 1 M sodium carbonate solution is used as the cathode chamber electrolyte; 4-amino-TEMPO is added to the anode chamber for the oxidation reaction; in the cathode chamber of the electrolytic cell, nickel foam is used as the counter electrode for the hydrogen evolution reaction;

[0050] S1: Using 19-hydroxy-4-androstene-3,17-dione as the reactant, take 3 g of 19-hydroxy-4-androstene-3,17-dione and 273.6 mg of 4-amino-TEMPO and add them to the electrolytic solution in the anode chamber;

[0051] S2: Place the entire electrolytic cell in a constant temperature water bath to control the reaction system temperature at 30 °C, stir, control the current density at 100 mA / cm 2 , control the voltage range at 0.6 - 1.0 V, and the flow rate of the electrolytic cell is 120 mL / min to carry out the electrolysis reaction;

[0052] S3: After cooling the electrolytic solution in the anode chamber in step S2 to room temperature, extract and layer it with dichloromethane, and evaporate and separate the dichloromethane phase to obtain the crude product of 19-formyl-4-androstene-3,17-dione. By tracking with HPLC, when the reaction reaches 33 minutes, the raw material conversion rate is 80%, and the selectivity of 19-formyl-4-androstene-3,17-dione is 92%.

[0053] Example 4: Synthesis of NiZn-MOF / GF and its electrocatalytic oxidation of 19-hydroxy-4-androstene-3,17-dione to prepare 19-formyl-4-androstene-3,17-dione

[0054] (1) Weigh 291 mg of nickel nitrate, 297 mg of zinc nitrate, and 265.6 mg of terephthalic acid and dissolve them in 40 mL of DMF and 20 mL of ethanol, and ultrasonically disperse them at room temperature for 20 minutes to obtain solution A;

[0055] (2) Add the solution A in step (1) and the carbon felt carrier to a hydrothermal reactor, carry out a hydrothermal reaction at 180 °C for 12 hours, then cool to room temperature, take out the carbon felt, wash it alternately with distilled water and ethanol 3 times, and dry it at 70 °C to obtain the carbon felt loaded with the nickel alloy-organic framework electrocatalyst, marked as NiZn-MOF / GF.

[0056] Test the catalytic performance of the nickel alloy-organic framework electrocatalyst prepared in Example 4. The specific method is as follows:

[0057] Cut the NiZn-MOF / GF to approximately 3×3 cm 2 in size and directly use it as the working electrode. The current is controlled by an electrochemical workstation, and a peristaltic pump continuously pumps the reaction solution into a continuous-flow electrolytic cell. The anode chamber and the cathode chamber have a volume of 250 mL and are separated by a proton exchange membrane. 70 mL of 1 M sodium carbonate solution and 30 mL of MeCN (organic solvent: sodium carbonate = 3:7) are used as the anode chamber electrolyte; 100 mL of 1 M sodium carbonate solution is used as the cathode chamber electrolyte; 4-hydroxy-TEMPO is added to the anode chamber as a mediator for the oxidation reaction; in the cathode chamber of the electrolytic cell, nickel foam is used as the counter electrode for the hydrogen evolution reaction;

[0058] S1: Take 3 g of 19-hydroxy-4-androstene-3,17-dione as the reactant and add 275.2 mg of 4-hydroxy-TEMPO to the electrolytic solution in the anode chamber;

[0059] S2: Place the entire electrolytic cell in a constant temperature water bath to control the reaction system temperature at 30 °C, stir, control the current density at 100 mA / cm 2 , control the voltage range at 0.6 - 1.0 V, and the flow rate of the electrolytic cell at 120 mL / min, and carry out the electrolysis reaction;

[0060] S3: After cooling the electrolytic solution in the anode chamber in step S2 to room temperature, extract and layer it with dichloromethane, and evaporate and separate the dichloromethane phase to obtain the crude product of 19-formyl-4-androstene-3,17-dione. By HPLC tracking, when the reaction reaches 33 minutes, the raw material conversion rate is 78%, and the selectivity of 19-formyl-4-androstene-3,17-dione is 90%.

[0061] Example 5: Synthesis of NiCu-MOF / GF and its electrocatalytic oxidation of 19-hydroxy-4-androstene-3,17-dione to prepare 19-formyl-4-androstene-3,17-dione

[0062] (1) Weigh 436.5 mg of nickel nitrate, 120.5 mg of copper nitrate, and 265.6 mg of terephthalic acid and dissolve them in 40 mL of DMF and 20 mL of ethanol, and ultrasonically disperse for 20 minutes at room temperature;

[0063] (2) Add the mixed solution in step (1) and the carbon felt carrier to a hydrothermal autoclave, carry out hydrothermal reaction at 150 °C for 12 hours, then cool to room temperature, take out the carbon felt, wash it alternately with distilled water and ethanol 3 times, and dry it at 70 °C to obtain the supported electrocatalyst, labeled as NiCu-MOF / GF.

[0064] Test the catalytic performance of the catalyst prepared in Example 5. The specific method is as follows:

[0065] The NiCu-MOF / GF was cut into a size of approximately 3×3 cm and directly used as the working electrode. The current was controlled by an electrochemical workstation, and the reaction solution was continuously pumped into a continuous-flow electrolytic cell by a peristaltic pump. The volumes of the anodic chamber and the cathodic chamber were 250 mL and were separated by a proton exchange membrane. 40 mL of 1 M sodium carbonate solution and 60 mL of MeCN (organic solvent: sodium carbonate = 6:4) were used as the electrolyte in the anodic chamber; 100 mL of 1 M sodium carbonate solution was used as the electrolyte in the cathodic chamber; 4-oxo-TEMPO was added to the anodic chamber as a mediator for the oxidation reaction; in the cathodic chamber of the electrolytic cell, nickel foam was used as the counter electrode for the hydrogen evolution reaction; 2 S1: Using 19-hydroxy-4-androstene-3,17-dione as the reactant, 3 g of 19-hydroxy-4-androstene-3,17-dione and 170 mg of 4-oxo-TEMPO were added to the electrolytic solution in the anodic chamber;

[0066] S2: The entire electrolytic cell was placed in a thermostatic water bath to control the reaction system temperature at 30 °C, stirred, the current density was controlled at 100 mA / cm

[0067] S2: The entire electrolytic cell was placed in a thermostatic water bath to control the reaction system temperature at 30 °C, stirred, the current density was controlled at 100 mA / cm², the voltage control range was 0.6 - 1.0 V, and the flow rate of the electrolytic cell was 120 mL / min for the electrolysis reaction; 2 S2: The entire electrolytic cell was placed in a thermostatic water bath to control the reaction system temperature at 30 °C, stirred, the current density was controlled at 100 mA / cm², the voltage control range was 0.6 - 1.0 V, and the flow rate of the electrolytic cell was 120 mL / min for the electrolysis reaction;

[0068] S3: After cooling the electrolytic solution in the anodic chamber in step S2 to room temperature, it was extracted and layered with dichloromethane, and the dichloromethane phase was separated by evaporation to obtain the crude product of 19-formyl-4-androstene-3,17-dione. Tracking by HPLC showed that when the reaction reached 33 minutes, the conversion rate of the raw material was 68%, and the selectivity of 19-formyl-4-androstene-3,17-dione was 85%.

[0069] Comparative Example 6: Synthesis of NiFe-LDH / GF and its electrocatalytic oxidation of 19-hydroxy-4-androstene-3,17-dione to prepare 19-formyl-4-androstene-3,17-dione

[0070] (1) Weigh 145.5 mg of nickel nitrate, 606 mg of iron nitrate, 148 mg of ammonium fluoride, and 360 mg of urea and dissolve them in 60 mL of distilled water, and ultrasonically disperse for 20 minutes at room temperature to obtain solution B;

[0071] (2) Add solution B in step (1) and the carbon felt carrier to a hydrothermal autoclave, carry out a hydrothermal reaction at 150 °C for 12 hours, then cool to room temperature, take out the carbon felt, wash it 3 times alternately with distilled water and ethanol, and dry it at 70 °C to obtain the carbon felt loaded with the nickel alloy-organic framework electrocatalyst, marked as NiFe-LDH / GF.

[0072] The catalytic performance of the catalyst prepared in Comparative Example 6 was tested, and the specific method was as follows:

[0073] The NiFe-LDH / GF catalyst was cut into approximately 3×3 cm 2 in size and directly used as the working electrode. The current was controlled by an electrochemical workstation, and a peristaltic pump continuously pumped the reaction solution into a continuous-flow electrolytic cell. The anode chamber and the cathode chamber had a volume of 250 mL and were separated by a proton exchange membrane. 40 mL of 1 M sodium carbonate solution and 60 mL of MeCN (organic solvent: sodium carbonate = 4:6) were used as the anode chamber electrolyte; 100 mL of 1 M sodium carbonate solution was used as the cathode chamber electrolyte; ACT was added to the anode chamber as a medium for the oxidation reaction; in the cathode chamber of the electrolytic cell, nickel foam was used as the counter electrode for the hydrogen evolution reaction;

[0074] S1: Using 19-hydroxy-4-androstene-3,17-dione as the reactant, 3 g of 19-hydroxy-4-androstene-3,17-dione and 213 mg of ACT were added to the electrolytic solution in the anode chamber;

[0075] S2: The entire electrolytic cell was placed in a thermostatic water bath to control the reaction system temperature at 30 °C, stirred, the current density was controlled at 100 mA / cm 2 , the voltage control range was 0.6 - 1.0 V, and the flow rate of the electrolytic cell was 120 mL / min to carry out the electrolytic reaction;

[0076] S3: After cooling the electrolytic solution in the anode chamber of step S2 to room temperature, it was extracted and layered with dichloromethane, and the dichloromethane phase was evaporated and separated to obtain the crude product of 19-aldehyde-4-androstene-3,17-dione. By HPLC tracking, when the reaction reached 33 minutes, the raw material conversion rate was 76%, and the selectivity of 19-aldehyde-4-androstene-3,17-dione was 90%.

[0077] Comparative Example 7: Synthesis of NiFe-MOF / GF and its electrocatalytic oxidation of 19-hydroxy-4-androstene-3,17-dione to prepare 19-aldehyde-4-androstene-3,17-dione

[0078] (1) Weigh 145.5 mg of nickel nitrate, 606 mg of iron nitrate and 265.6 mg of terephthalic acid and dissolve them in 40 mL of DMF and 20 mL of ethanol, and ultrasonically disperse for 20 minutes at room temperature to obtain solution A;

[0079] (2) Add the solution A in step (1) and the carbon felt carrier to a hydrothermal autoclave, carry out a hydrothermal reaction at 150 °C for 12 hours, then cool to room temperature, take out the carbon felt, wash it 3 times alternately with distilled water and ethanol, and dry it at 70 °C to obtain the carbon felt loaded with the nickel alloy-organic framework electrocatalyst, marked as NiFe-MOF / GF.

[0080] The catalytic performance of the carbon felt loaded with the nickel alloy-organic framework electrocatalyst prepared in Comparative Example 7 was tested, and the specific method is as follows:

[0081] Cut the NiFe-MOF / GF to about 3×3 cm 2 in size and directly use it as the working electrode; a platinum sheet is used as the counter electrode. The current is controlled by an electrochemical workstation. A kettle electrolytic cell with a volume of 100 mL is used, and 40 mL of 1M sodium carbonate solution and 60 mL of MeCN (organic solvent: sodium carbonate = 4:6) are used as the electrolyte;

[0082] S1: Using 19-hydroxy-4-androstene-3,17-dione as the reactant, take 3 g of 19-hydroxy-4-androstene-3,17-dione and 213 mg of ACT and add them to the electrolytic solution in the anode chamber;

[0083] S2: Place the entire electrolytic cell in a constant temperature water bath to control the reaction system temperature at 30 °C, stir, and control the current density at 5 mA / cm 2 , and control the voltage range at 0.6 - 1.0 V to carry out the electrolysis reaction;

[0084] S3: After cooling the electrolytic solution in the anode chamber in step S2 to room temperature, extract and layer it with dichloromethane, and evaporate and separate the dichloromethane phase to obtain the crude product of 19-aldehyde-4-androstene-3,17-dione. Track by HPLC. When the reaction reaches 633 minutes, the raw material conversion rate is 55%, and the selectivity of 19-aldehyde-4-androstene-3,17-dione is 90%.

[0085] The reaction conditions and results of Examples 1-5 and Comparative Examples 6-7 are shown in Table 1

[0086] Table 1 Summary of reaction conditions and reaction results of Examples 1-5 and Comparative Examples 6 and 7

[0087]

[0088] It can be seen from Table 1 that under the same conditions, the bimetallic organic framework has a large increase in conversion rate and selectivity compared with the layered bimetallic hydroxide NiFe-LDH / GF catalyst. The NiFe-MOF / GF in Example 1 of the present invention has extremely excellent performance. When the reaction time is 2000 s, the conversion rate of 19-hydroxy-4-androstene-3,17-dione is 99%, and the selectivity for 19-aldehyde-4-androstene-3,17-dione is 99%. It can be seen from Examples 1 and 6 that using a continuous flow electrolytic cell, the reaction time is short, and the conversion rate and selectivity are much greater than those of a kettle electrolytic cell.

[0089] The above-described embodiments are only a preferred solution, and there are other variations and modifications without exceeding the technical solutions described in the claims.

Claims

1. Application of a nickel alloy-organic framework electrocatalyst in the oxidation for preparing 19-formyl-4-androstene-3,17-dione, characterized in that, The specific implementation method is as follows: use an electrochemical workstation to control the reaction current, use a carbon felt loaded with a nickel alloy-organic framework electrocatalyst as the working electrode, and use a continuous flow electrolytic cell for the reaction. The anode chamber and the cathode chamber are separated by a proton exchange membrane. After ultrasonic dissolution of 19-hydroxy-4-androstene-3,17-dione, an alkaline solution, an organic solvent, and a nitroxide radical, they are placed in a constant temperature water bath and stirred as the anolyte; the alkaline solution is used as the catholyte. The anolyte and the catholyte are continuously pumped into the anode chamber and the cathode chamber respectively by a peristaltic pump. Set the reaction temperature to 30-60 °C and the current density to 10-200 mA / cm 2 , the anode voltage is 0.6-1.0 V. Under this test condition, electrocatalytic selective oxidation is carried out. When there is no reactant signal detected by HPLC, the reaction is terminated and an organic solvent is added for extraction to obtain an organic extract. The organic layer is rotary evaporated to obtain 19-formyl-4-androstene-3,17-dione. The anodic reaction equation is as follows: ； A preparation method of a nickel alloy-organic framework electrocatalyst includes the following steps: 1) Dissolve nickel nitrate, non-noble metal salt A and terephthalic acid in DMF, then add ethanol, and ultrasonically disperse the solution to obtain solution A. The non-noble metal salt A is selected from ferric nitrate, cobalt nitrate, copper nitrate, manganese nitrate or zinc nitrate; 2) Add solution A to a hydrothermal reactor, then add carbon felt, react at 80-180 °C for 6-24 hours, cool to room temperature after the reaction, take out the carbon felt after loading, wash it alternately with distilled water and ethanol, and then place it in a blast drying oven at 40-100 °C and dry for 6-18 hours to obtain a supported nickel alloy-organic framework electrocatalyst.

2. The application according to claim 1, characterized in that The mass ratio of nickel nitrate, non-noble metal salt A and terephthalic acid is 1-6:1.5-9:1.5-4.

3. The application according to claim 1, characterized in that The concentration of 19-hydroxy-4-androstene-3,17-dione in the anolyte is 50-200 mmol / L.

4. The application according to claim 1, wherein The flow rate of the continuous flow electrolytic cell is 40-200 mL / min.

5. The application according to claim 1, characterized in that The alkaline solution added to the anolyte is sodium carbonate solution, sodium bicarbonate solution or sodium hydroxide solution, the concentration of the alkaline solution is 0.5-2.0 mol / L, the organic solvent is one of tetrahydrofuran, dichloromethane, acetonitrile and acetone, and the alkaline solution in the catholyte is sodium carbonate solution.

6. The application according to claim 1, wherein The nitroxide radical added to the anolyte is TEMPO, 4-amino-TEMPO, ACT, 4-Cl-acetamido-TEMPO or 4-oxo-TEMPO, and the concentration of the nitroxide radical in the anolyte is 0.5-15 mmol / L.

7. The application according to claim 5, characterized in that The feeding volume ratio of the alkaline solution and the organic solvent in the anolyte is 1:4-4:

1.

8. The application according to claim 1, wherein The organic solvent used for extraction is toluene, dichloromethane, chloroform, ethyl acetate or petroleum ether.

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