Method for synthesizing 1-methoxy-2-acetone through electrocatalysis of 1-methoxy-2-propanol by using high-entropy alloy CoNiMnMoCu

Abstract

The invention discloses a method for synthesizing 1-methoxy-2-acetone from high-entropy alloy CoNiMnMoCu through electro-catalysis of 1-methoxy-2-propanol, and belongs to the technical field of electro-catalytic synthesis of organics. The high-entropy alloy CoNiMnMoCu synthesized by transition metal is used as an anode electro-catalyst in an alkaline electrolyte, electro-catalytic oxidation is carried out under indoor natural conditions, and the 1-methoxy-2-acetone is obtained. After the reaction is finished, extraction separation and distillation purification are performed, and the purified target product is 1-methoxy-2-acetone. The invention provides a green and efficient synthesis method of 1-methoxy-2-acetone, and a foundation is laid for industrialization of alcohol and aldehyde electrooxidation appreciation in the future.

Description

Technical Field

[0001] The present invention relates to the technical field of electrocatalytic synthesis of organic compounds, and particularly to a method for electrocatalytic oxidation synthesis of 1-methoxy-2-acetone using 1-methoxy-2-propanol as a raw material and a high-entropy alloy CoNiMnMoCu as an anode catalyst. Background Art

[0002] 1-methoxy-2-acetone is a high-value-added chemical with extremely wide applications. Especially, it is widely used as an intermediate of the herbicide metolachlor in agriculture in China. It is also a low-toxic and high-efficiency organic solvent and is widely used in industries such as paints, daily cleaning agents, dyes, and textiles.

[0003] Currently, the methods for preparing 1-methoxy-2-acetone in the literature and patents are all synthesized by traditional chemical oxidation methods. For example, Raymond P.M and his team tried a method of chemical oxidation using sodium dichromate and sulfuric acid to synthesize 1-methoxy-2-acetone. Although this process can efficiently promote the conversion of raw materials, the selectivity of 1-methoxy-2-acetone is relatively low and this method causes significant environmental pollution problems. Mallat T, Baiker A and others used the air oxidation method. However, in the presence of sufficient oxygen, the metal catalyst is prone to poisoning and inactivation, and the catalyst needs to be replaced regularly, resulting in high production costs. In addition, the yield of this method is relatively low and the selectivity is poor. In recent years, Zhao Yu and others prepared a Cu-Al2O3 catalyst by an improved co-precipitation method. This catalyst exhibits the characteristics of high specific surface area and high dispersion, making the conversion rate of raw materials reach more than 80%. However, its selectivity is only about 50%. Patent CN116889885A also discloses a catalyst for the synthesis process of 1-methoxy-2-acetone. 1-methoxy-2-propanol is mixed with an inert gas, and then reacted in a continuous flow packed bed reactor in the presence of a catalyst under the conditions of a reaction temperature of 150-220 °C and a reaction pressure of normal pressure to obtain the target product. The catalyst uses a bimetallic main active component of Ba and Cu, a functional element N as an electronic modifier, and nano-spherical silica as a catalyst carrier, wherein the Ba content is 0.1%-20% of the catalyst mass, and the Cu content is 10%-30% of the catalyst mass.

[0004] In summary, the reported synthesis methods of 1-methoxy-2-acetone currently all belong to traditional chemical oxidation synthesis methods. This method has many problems: the need to add toxic and harmful strong oxidants, harsh reaction conditions, complex reaction equipment, etc. It has become particularly important to explore and develop a green and efficient production route for 1-methoxy-2-acetone. Summary of the Invention

[0005] In order to overcome the disadvantages of the existing technology, the present invention provides a new method for synthesizing 1-methoxy-2-propanone that is environmentally friendly, has mild reaction conditions and is easy to control. Using inexpensive and readily available 1-methoxy-2-propanol as the raw material, 1-methoxy-2-propanone is efficiently electrocatalytically oxidized using a high-entropy alloy catalyst.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for electrocatalytic synthesis of 1-methoxy-2-propanone from 1-methoxy-2-propanol using a high-entropy alloy CoNiMnMoCu. Put 1-methoxy-2-propanol into the electrolyte solution, and use the high-entropy alloy CoNiMnMoCu as the anode catalyst for electrolysis to synthesize 1-methoxy-2-propanone.

[0008] Furthermore, after the electrolysis reaction is completed, the electrolyte solution is subjected to extraction separation and distillation purification to obtain the target product 1-methoxy-2-propanone.

[0009] Specifically, assemble the anode, cathode and electrolytic cell group into an electrolysis device. Put 1-methoxy-2-propanol into the electrolyte solution, use the high-entropy alloy CoNiMnMoCu as the anode catalyst, and connect the positive and negative electrodes of the DC power supply to the anode and cathode respectively for electrolysis to synthesize 1-methoxy-2-propanone. Furthermore, electrolysis is carried out in a constant current mode, and the current density is 10-100 mA / cm 2 .

[0010] The electrolyte solution is a common electrolyte solution, including but not limited to aqueous solutions of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, disodium hydrogen phosphate, and dipotassium hydrogen phosphate. The concentration of the electrolyte solution is preferably 0.01-1.0 mol / L. As a preference, the electrolyte solution is a potassium hydroxide or sodium hydroxide solution. Both are strong bases, which can create an alkaline environment conducive to alcohol oxidation and accelerate the reaction process. They have good solubility in polar solvents such as water and alcohol, can form a homogeneous reaction system, and the dissociated ions endow the solution with high conductivity to ensure efficient electron transfer. At the same time, their chemical stability is good and they are not easily decomposed under the reaction conditions. Moreover, due to the mature process, large output, relatively low cost, and extremely convenient storage, transportation and operation, they are practical and economical electrolyte choices in alcohol oxidation reactions. The cathode includes but is not limited to commercial Raney nickel, platinum sheet, carbon plate, nickel plate.

[0011] The concentration of 1-methoxy-2-propanol in the electrolyte solution is preferably 0.05-0.5 mol / L.

[0012] The anode catalyst high-entropy alloy CoNiMnMoCu is prepared by a one-pot co-reduction method, and the specific synthesis process is as follows:

[0013] (1) Dissolve cobalt salt, nickel salt, manganese salt, molybdenum salt, and copper salt in deionized water to form a uniformly mixed reaction solution. The molar ratio of Co 2+ , Ni 2+ , Mn 2+ , Mo 7+ , Cu 2+ in the reaction solution is 1:1:1:1:1;

[0014] (2) Rapidly add the newly prepared NaBH4 solution to the reaction solution at 60 - 90 °C, carry out a reduction reaction for 30 - 60 min. After the reaction is completed, centrifuge and wash to obtain the high-entropy alloy CoNiMnMoCu.

[0015] Further, the high-entropy alloy CoNiMnMoCu is ultrasonically dispersed in a Nafion mixed solution, and then dropped onto a glassy carbon electrode and dried at room temperature to serve as the anode. The Nafion mixed solution is prepared from ultrapure water, ethanol, and a Nafion (5 wt%) solution.

[0016] The cobalt salt, nickel salt, manganese salt, molybdenum salt, and copper salt are soluble salts. For example, the cobalt salt is any one of Co(NO3)2·6H2O, CoSO4·7H2O, and CoCl2·6H2O; the nickel salt is any one of Ni(NO3)2·6H2O, NiSO4·6H2O, and NiCl2·6H2O; the manganese salt is any one of Mn(NO3)2·xH2O, MnSO4·4H2O, and MnCl2·4H2O; the molybdenum salt is any one of (NH4)6Mo7O 24 ·4H2O and Na2MoO4·2H2O; the copper salt is any one of Cu(NO3)2·3H2O, CuSO4·5H2O, and CuCl2·2H2O.

[0017] Compared with the prior art, the present invention has the following advantages and effects:

[0018] (1) The anode catalyst of the present invention is obtained by a one-pot co-reduction method, and the preparation method is simple.

[0019] (2) The method of the present invention does not require additional addition of other oxidants, can be carried out under natural conditions at room temperature, has low cost, requires simple equipment, and is conducive to management and regulation.

[0020] (3) The conversion rate and yield of 1-methoxy-2-propanone in the method of the present invention are as high as over 90%, and it is a green and efficient process synthesis route. Brief Description of the Drawings

[0021] Figure 1 It is the SEM image of the high-entropy alloy CoNiMnMoCu prepared in Example 1.

[0022] Figure 2 It is a schematic diagram of the principle for the high-entropy alloy of the present invention to efficiently electrocatalyze the synthesis of 1-methoxy-2-acetone from 1-methoxy-2-propanol.

[0023] Figure 3 It is the gas chromatogram of the electrolysis product in the application example.

[0024] Figure 4 It is the result diagram of the durability experiment of the high-entropy alloy CoNiMnMoCu prepared in Example 1. Specific Embodiments

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0026] Example 1

[0027] (1) Co(NO3)2·6H2O, (NH4)6Mo7O 24 ·4H2O, Ni(NO3)2·6H2O, Mn(NO3)2·xH2O and Cu(NO3)2·3H2O were added to water, and ultrasonic was used to accelerate dissolution to prepare a uniformly mixed reaction solution. The molar ratio of Co 2+ , Ni 2+ , Mn 2+ , Mo 7+ , Cu 2+ in the reaction solution was 1:1:1:1:1;

[0028] (2) The newly prepared NaBH4 solution was quickly added to the reaction solution at 60 - 90 °C, and the reaction was carried out for 30 - 60 min. Then, the obtained black-brown precipitate was collected by centrifugation, and then washed several times with water to obtain the high-entropy alloy CoNiMnMoCu.

[0029] It can be seen from Figure 2 that the catalyst is in a 3D nanoporous network structure, which can expose abundant active sites, facilitate the adsorption and activation of substrates, and accelerate the electrocatalytic reaction.

[0030] Comparative Example 1

[0031] In this comparative example, except that Ni(NO3)2·6H2O was not added in step (1), the others were the same as in Example 1, and finally the alloy CoMnMoCu was prepared.

[0032] Comparative Example 2

[0033] This comparative example is the same as Example 1 except that Co(NO3)2·6H2O was not added in step (1), and finally the alloy NiMnMoCu was obtained.

[0034] Application Example

[0035] The high-entropy alloy catalyst CoNiMnMoCu prepared in Example 1 and the alloys CoMnMoCu and NiMnMoCu prepared in Comparative Examples 1-2 were ultrasonically dispersed in a Nafion mixed solution, and then dropped onto a glassy carbon electrode and dried at room temperature to serve as the anode. Commercial Raney nickel was used as the cathode, and 1 M KOH was used as the electrolyte to assemble a diaphragm-free electrolysis device. The Nafion mixed solution was prepared from ultrapure water, ethanol, and a Nafion (5 wt%) solution. The positive and negative electrodes of a DC power supply were respectively connected to the anode and cathode of the electrolytic cell, and a direct current with a current density of 40 mA / cm 2 was applied for electrocatalytic oxidation. During the electrolysis process, the temperature and pressure were not controlled at all. After the reaction ended, the electrolyte was extracted, separated, and purified by distillation, and qualitative and quantitative detection was carried out using a high-performance gas chromatograph GC-2014. The conversion rate and yield of 1-methoxy-2-propanone after calculation are shown in the following table.

[0036] catalyst conversion rate yield high-entropy alloy CoNiMnMoCu 95.67％ 90.94％ alloy CoMnMoCu 59.67％ 50.16％ alloy NiMnMoCu 70.10％ 61.29％

[0037] To verify the stability of CoNiMnMoCu during the electrocatalytic oxidation reaction of MOP, we carried out a stability test for 6 cycles on it. As Figure 4 shown, the Faraday efficiency of CoNiMnMoCu remained stable throughout the test period, indicating that the catalyst has good stability.

Claims

1. A method for electrocatalytic synthesis of 1-methoxy-2-acetone from 1-methoxy-2-propanol using a high-entropy alloy CoNiMnMoCu, characterized in that, 1-Methoxy-2-propanol is put into the electrolyte, and high-entropy alloy CoNiMnMoCu is used as the anode catalyst for electrolysis to synthesize 1-methoxy-2-acetone.

2. The method for electrocatalytic synthesis of 1-methoxy-2-acetone from 1-methoxy-2-propanol using the high-entropy alloy CoNiMnMoCu according to claim 1, characterized in that, After the electrolysis reaction is completed, the electrolyte is subjected to extraction separation and distillation purification to obtain the target product 1-methoxy-2-acetone.

3. The method for electrocatalytic synthesis of 1-methoxy-2-acetone from 1-methoxy-2-propanol using the high-entropy alloy CoNiMnMoCu according to claim 1, characterized in that, An anode, a cathode and an electrolytic cell group are assembled into an electrolytic device. 1-Methoxy-2-propanol is put into the electrolyte. A high-entropy alloy CoNiMnMoCu is used as the anode catalyst. The positive and negative electrodes of a DC power supply are respectively connected to the anode and the cathode for electrolysis to synthesize 1-methoxy-2-acetone. The electrolysis is carried out in a constant current mode with a current density of 10-100 mA / cm 2 .

4. The method for electrocatalytic synthesis of 1-methoxy-2-acetone from 1-methoxy-2-propanol using the high-entropy alloy CoNiMnMoCu according to claim 1, characterized in that, The electrolyte is an aqueous solution of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, disodium hydrogen phosphate or dipotassium hydrogen phosphate, and the electrolyte concentration is preferably 0.01-1.0 mol / L.

5. The method for electrocatalytic synthesis of 1-methoxy-2-acetone from 1-methoxy-2-propanol using the high-entropy alloy CoNiMnMoCu according to claim 1, wherein The concentration of 1-methoxy-2-propanol in the electrolyte is 0.05-0.5 mol / L.

6. The method for electrocatalytic synthesis of 1-methoxy-2-acetone from 1-methoxy-2-propanol using the high-entropy alloy CoNiMnMoCu according to claim 1, characterized in that, The anode catalyst high-entropy alloy CoNiMnMoCu is prepared by a one-pot co-reduction method, and the specific synthesis process is as follows: (1) Dissolve cobalt salt, nickel salt, manganese salt, molybdenum salt, and copper salt in deionized water to prepare a uniformly mixed reaction solution. The molar ratio of Co 2+ , Ni 2+ , Mn 2+ , Mo 7+ , Cu 2+ in the reaction solution is 1:1:1:1:1; (2) The newly prepared NaBH4 solution is rapidly added to the reaction solution at 60-90 °C, and the reduction reaction is carried out for 30-60 min. After the reaction is completed, centrifugation and washing are carried out to obtain the high-entropy alloy CoNiMnMoCu.

7. The method for electrocatalytic synthesis of 1-methoxy-2-acetone from 1-methoxy-2-propanol using the high-entropy alloy CoNiMnMoCu according to claim 1, characterized in that, The high-entropy alloy CoNiMnMoCu is ultrasonically dispersed in the Nafion mixed solution, and then dropped onto the glassy carbon electrode and dried at room temperature as the anode. The Nafion mixed solution is prepared from ultrapure water, ethanol and 5 wt% Nafion solution.

8. The method for electrocatalytic synthesis of 1-methoxy-2-acetone from 1-methoxy-2-propanol using the high-entropy alloy CoNiMnMoCu according to claim 1, wherein, The cobalt salt, nickel salt, manganese salt, molybdenum salt, and copper salt are soluble salts. The cobalt salt is any one of Co(NO3)2·6H2O, CoSO4·7H2O, and CoCl2·6H2O; the nickel salt is any one of Ni(NO3)2·6H2O, NiSO4·6H2O, and NiCl2·6H2O; the manganese salt is any one of Mn(NO3)2·xH2O, MnSO4·4H2O, and MnCl2·4H2O; the molybdenum salt is any one of (NH4)6Mo7O 24 ·4H2O and Na2MoO4·2H2O; the copper salt is any one of Cu(NO3)2·3H2O, CuSO4·5H2O, and CuCl2·2H2O.

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