Electrochemical preparation method of heliotropin

Abstract

The invention provides an electrochemical preparation method of heliotropin, which comprises the following steps: 1) mixing 3, 4-(methylenedioxy) toluene, an alcohol solvent, water, halide and a sulfonate anionic surfactant to obtain an electrolyte, and adding the electrolyte into an electrolytic bath; and 2) electrifying the electrolyte in the electrolytic bath in the step 1) to react, and generating heliotropin at an anode by using 3, 4-(methylenedioxy) toluene and an alcohol solvent. The method has the advantages of high reaction yield, high atom economy, simple steps, less three wastes, low energy consumption and low cost.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of heliotropein, and particularly relates to an electrochemical preparation method of heliotropein. Background Art

[0002] Heliotropin is chemically known as 3,4-dimethoxybenzaldehyde, with a molecular formula of C8H6O3. It is also known as piperic acid and heliotropin. It is named for its scent, which is similar to that of heliotropin. It is a safe fragrance used to formulate a variety of daily fragrances. It can also be applied to medicine, food, and agriculture, and has good market prospects. Heliotropin is widely found in plants such as heliotropin, locust flowers, camphor wood, and violet flowers. However, the content of heliotropin in various plants is very low, making it difficult to obtain on a large scale through plant extraction methods. Therefore, the heliotropin currently on the market is mainly prepared by chemical synthesis. Depending on the starting raw materials for the synthesis, common synthesis routes include safrole route, vanillin route, and piperonyl ring route.

[0003] CN117756773A provides a process for preparing heliotropein. The process involves slowly adding concentrated sulfuric acid and piperonyl cyclopentane to a mixture of glyoxylic acid and acetic acid to produce piperonyl glycolic acid. The piperonyl glycolic acid is then oxidized, followed by extraction, crude distillation, decolorization, rectification, and crystallization to produce heliotropein. This method produces heliotropein with a purity exceeding 99%. However, this method has the disadvantages of requiring many reaction steps, resulting in low yield and high energy consumption.

[0004] CN118146187A provides a process for preparing piperonal: using piperonyl as the raw material, piperonal is obtained through chloromethylation and oxidation with an oxygen-containing gas as the oxidant. This method operates under normal pressure, has mild conditions, good selectivity, and high yield, but requires a large amount of acid and high waste treatment costs.

[0005] JP1987056954B2 discloses a method for preparing piperonal by electrolytically reacting piperonal. This method uses piperonal as a raw material and oxidatively decomposes it to produce piperonal. The raw material, isosafrole diol, needs to be obtained by treating isosafrole with hydrogen peroxide, performic acid, or peracetic acid. This method has disadvantages such as difficulty in obtaining the raw material, high cost, and low reaction yield.

[0006] GB2165536B discloses a method for preparing piperonal using 4-methyl-methylenedioxybenzene as a raw material and oxidation with cerium sulfate. The raw material, 4-methyl-methylenedioxybenzene, is produced by an elimination reaction between 3,4-dihydroxytoluene, a coal tar derivative, and a disubstituted methane derivative. Cerium sulfate is produced by oxidizing an aqueous sulfuric acid solution of cerous sulfate in an electrochemical cell. This method achieves an 83% yield of piperonal based on the cerium sulfate used and a 90% yield based on the consumed raw materials. However, due to the intermittent electrooxidation of cerium sulfate as the raw material, this method suffers from multiple reaction steps, significant raw material losses, and high production costs.

[0007] In summary, since the current method for synthesizing jasminoids has many disadvantages such as many reaction steps, high energy consumption, heavy pollution, and high raw material costs, it is of great significance to develop a clean, environmentally friendly, and low-cost method for synthesizing jasminoids. Summary of the Invention

[0008] In response to the above-mentioned deficiencies in the prior art, the present invention aims to provide an electrochemical method for preparing heliotropin, which uses 3,4-(methylenedioxy)toluene as a raw material, alcohol and water as solvents, and improves product yield by adding halide and sulfonate anionic surfactants. The method has high conversion rate and selectivity, a wide range of raw material sources, simple steps, high atom economy, low waste, low energy consumption, and low cost.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] The present invention provides an electrochemical preparation method of heliotropin, comprising the following steps:

[0011] 1) mixing 3,4-(methylenedioxy)toluene, an alcohol solvent, water, a halide, and a sulfonate anionic surfactant to obtain an electrolyte, and adding the electrolyte to an electrolytic cell;

[0012] 2) The electrolyte in the electrolytic cell of step 1) is energized to react, and 3,4-(methylenedioxy)toluene and an alcohol solvent are used to generate heliotropein at the anode.

[0013] In one embodiment of the present invention, the alcohol solvent in step 1) is selected from C1-C3 alcohols, preferably any one or a combination of at least two of methanol, ethanol, and propylene glycol, more preferably methanol and / or ethanol.

[0014] In one embodiment of the present invention, the halide in step 1) is a metal halide, preferably any one of metal chloride, metal bromide, and metal iodide, or a combination of at least two thereof, more preferably a metal bromide;

[0015] In some specific examples, optionally, the halide is selected from any one or a combination of at least two of sodium chloride, potassium chloride, potassium bromide, sodium bromide, potassium iodide, sodium iodide, magnesium chloride, and magnesium bromide, preferably potassium bromide and / or sodium bromide.

[0016] In one embodiment of the present invention, the sulfonate anionic surfactant in step 1) is selected from any one or a combination of at least two of sodium dodecylbenzene sulfonate, sodium branched dodecylbenzene sulfonate, sodium α-olefin sulfonate, sodium secondary alkyl sulfonate and sodium hexadecyl diphenyl ether disulfonate, preferably sodium α-olefin sulfonate and / or sodium secondary alkyl sulfonate.

[0017] In one embodiment of the present invention, the mass ratio of 3,4-(methylenedioxy)toluene, alcohol solvent, and water added in step 1) is 1:2-5:0.1-0.5, preferably 1:3-4:0.3-0.4. In detail, in step 1), the mass ratio of 3,4-(methylenedioxy)toluene to alcohol solvent added includes but is not limited to 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, or a range consisting of any two thereof; the mass ratio of 3,4-(methylenedioxy)toluene to water added includes but is not limited to a range consisting of any two thereof.

[0018] In one embodiment of the present invention, the amount of the halide added in step 1) is 0.5-5% of the molar amount of 3,4-(methylenedioxy)toluene, including but not limited to 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% or a range composed of any two thereof, preferably 1-3%.

[0019] In one embodiment of the present invention, the amount of the sulfonate anionic surfactant salt added in step 1) is 0.3-1% of the total mass of the electrolyte, including but not limited to 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1% or a range composed of any two thereof, preferably 0.5-0.8%.

[0020] In one embodiment of the present invention, the reaction in step 2) is performed at a temperature of 20-60°C, preferably 30-40°C, and for a time of 10-40 hours, preferably 20-30 hours. Specifically, the reaction temperature includes, but is not limited to, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, or any range therebetween; and the reaction time includes, but is not limited to, 10 hours, 15 hours, 20 hours, 25 hours, 30 hours, 35 hours, 40 hours, or any range therebetween.

[0021] In one embodiment of the present invention, in step 2), the electrolytic cell voltage range is 6-10V, preferably 7-8V; the current density is 500-2000A / m 2 , preferably 500-1000A / m 2 Specifically, the electrolytic cell voltage includes but is not limited to 6V, 7V, 8V, 9V, 10V or any range between two thereof; the current density includes but is not limited to 500A / m 2 , 800A / m 2 、1000A / m 2 、1300A / m 2 、1500A / m 2 、1800A / m 2 , 2000A / m 2 Or a range between any two of them.

[0022] In one embodiment of the present invention, after the reaction of step 2) is completed, conventional post-processing operations in the fields of desolvation, desalination, distillation, and recrystallization are also included. For example, in some examples, methanol, bromide salts, and sulfonate anionic surfactant salts can be removed by distillation to obtain a crude product of jasminoid, which is then recrystallized by adding ethanol to obtain a finished product of jasminoid. These post-processing processes such as distillation and recrystallization are all known processes in the field, and their related operations and process conditions, as well as the devices used therein, can all be carried out using conventional selections in the art. Technicians can optimize the process based on the known processes in the prior art according to actual needs, and the present invention is not particularly limited thereto.

[0023] In step 2) of the present invention, power is applied to react, and 3,4-(methylenedioxy)toluene and an alcohol solvent undergo electrolytic oxidation at the anode, followed by hydrolysis to produce heliotrope. Further analysis of the reaction mechanism reveals that 3,4-(methylenedioxy)toluene and an alcohol solvent undergo electrolytic oxidation at the anode, followed by hydrolysis to produce heliotrope. Specifically, the process simultaneously includes the oxidation of 4-(methylenedioxy)toluene on the surface of the anode electrode to synthesize heliotrope diacetal compounds, and the hydrolysis of the heliotrope diacetal compounds to generate heliotrope aldehyde. After power is turned on and the temperature is increased, the two reactions can proceed simultaneously at the anode without an obvious order of priority. The type of the intermediate heliotrope diacetal compound generated by electrolytic oxidation is related to the alcohol solvent. For example, if methanol is used as the solvent, the intermediate is heliotrope dimethyl acetal (CAS No. 59259-90-4); if ethanol is used as the solvent, the intermediate is heliotrope diethyl acetal (CAS No. 40527-42-2); if propylene glycol is used as the solvent, the intermediate is heliotrope propylene glycol acetal (CAS No. 61683-99-6).

[0024] The present invention has found in the research of electrochemical synthesis of pyrrolidone that, with 3,4-(methylenedioxy)toluene as the starting raw material, electricity is passed through to react, and pyrrolidone dimethyl acetal can be first oxidized on the surface of the anode electrode to synthesize pyrrolidone dimethyl acetal, and the generated pyrrolidone dimethyl acetal is then hydrolyzed in the system to obtain pyrrolidone. At the same time, the present invention introduces a sulfonate anionic surfactant into the system, which can be adsorbed on the interface between the electrode and the solution, thereby reducing the interfacial tension and forming a transmission channel of 3,4-(methylenedioxy)toluene from the solution to the electrode surface, thereby ensuring the raw material concentration on the electrode surface and reducing the side reaction selectivity. In addition, the present invention also introduces halide ions into the system, which lose electrons and are oxidized on the anode surface to generate corresponding halogen elements or hypohalous acid, which can react with the reactants to promote the reaction rate and yield of 3,4-(methylenedioxy)toluene oxidized on the surface of the anode electrode to synthesize pyrrolidone dimethyl acetal.

[0025] In one embodiment of the present invention, the electrolytic cell is a diaphragmless electrolytic cell.

[0026] In one embodiment of the present invention, the electrolytic cell comprises an anode electrode and a cathode electrode;

[0027] In some specific examples, the anode electrode and the cathode electrode are both selected from graphite electrodes or DSA electrodes, and the anode electrode and the cathode electrode may be the same or different;

[0028] In some preferred examples, the DSA electrode is any one of Ti-based PbO2, IrO2, RuO2 or tin antimony oxide electrodes;

[0029] In some specific examples, the electrolytic cell is made of polypropylene (PP), polytetrafluoroethylene (PTFE) or titanium, preferably titanium.

[0030] In the preparation method of the present invention, there is no restriction on the shape and arrangement of the electrodes in the electrolytic cell. All electrode shapes and arrangements of cathodes and anodes that can realize the electrolysis function are covered by the method of the present invention.

[0031] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0032] The invention uses 3,4-(methylenedioxy)toluene as a starting material and reacts it with an alcohol solvent through electricity to prepare heliotropin. The invention has the advantages of simple steps, high total product yield, small equipment investment, low operation risk, mild reaction conditions, less three wastes, and low energy consumption, and is suitable for wide industrial applications. DETAILED DESCRIPTION

[0033] The preparation method provided by the present invention is further described in detail below through examples, but the present invention is not limited to the listed examples, and also includes any other known changes within the scope of the rights claimed by the present invention.

[0034] The sources of the main reagents and raw materials used in the examples and comparative examples of the present invention are as follows. Unless otherwise specified, the remaining reagents and raw materials are common commercially available products:

[0035] 3,4-(Methylenedioxy)toluene: Beijing Inokai Technology Co., Ltd., purity 97%;

[0036] Potassium chloride: Beijing Yinuokai Technology Co., Ltd., purity 99%;

[0037] Sodium chloride: Beijing Yinuokai Technology Co., Ltd., purity 99.8%;

[0038] Potassium bromide: Beijing Yinuokai Technology Co., Ltd., purity 99%;

[0039] Sodium bromide: Beijing Yinuokai Technology Co., Ltd., purity 99%;

[0040] Sodium iodide: Beijing Yinuokai Technology Co., Ltd., purity 98%;

[0041] Potassium iodide: Beijing Yinuokai Technology Co., Ltd., purity 99%;

[0042] Magnesium chloride: Beijing Yinuokai Technology Co., Ltd., purity 99.9%;

[0043] Magnesium bromide: Beijing Yinuokai Technology Co., Ltd., purity 98%;

[0044] Sodium secondary alkyl sulfonate: J&K Technology, purity 60%;

[0045] Sodium dodecylbenzenesulfonate: Shanghai Aladdin Biochemical Technology Co., Ltd., purity 95%;

[0046] Sodium α-olefin sulfonate: Zanyu Technology Group Co., Ltd., active matter: 92%

[0047] Sodium hexadecyl diphenyl ether disulfonate: Shanghai Jizhi Biochemical Technology Co., Ltd., purity 96%;

[0048] Methanol: Shanghai Aladdin Biochemical Technology Co., Ltd., purity AR, 99%;

[0049] Ethanol: Beijing Yinuokai Technology Co., Ltd., purity 99.9%;

[0050] Propylene glycol: Beijing Yinuokai Technology Co., Ltd., purity 98%;

[0051] The device used in the examples and comparative examples of the present invention is a diaphragmless electrolyzer: Jiangsu Ankaite Technology Co., Ltd.

[0052] The main test methods used in the examples and comparative examples of the present invention are as follows:

[0053] The present invention uses a gas chromatography area correction normalization method, using an Agilent 8890 gas chromatograph, an HP-5 capillary column (30.0 mm x 320 μm x 0.25 μm), a hydrogen flame detector, and nitrogen as the carrier gas. The heating program was as follows: initial temperature of 80°C, held for 1 minute, then increased at 10°C / min to 150°C, held for 3 minutes, and then increased at 10°C / min to 250°C; the injection port temperature was 250°C, and the feed volume was 2 μL.

[0054] In the following examples, the structure of heliotropin was characterized by hydrogen spectrum using a nuclear magnetic resonance spectrometer (Brucker ARX-400).

[0055] Heliotropin selectivity = heliotropin molar yield / 4-(methylenedioxy)toluene molar consumption * 100%

[0056] Current efficiency = molar yield of heliotropin * 4 * 96500 / (electrolysis current * electrolysis time) * 100%.

[0057] Example 1

[0058] Electrochemical preparation of heliotropin, the steps are:

[0059] 1) Take 50g 3,4-(methylenedioxy)toluene, 100g methanol, 25g water, 0.41g potassium chloride, 0.32g sodium chloride and 0.53g sodium dodecylbenzenesulfonate, mix them evenly, and add them to a diaphragmless electrolytic cell. The mass ratio of 3,4-(methylenedioxy)toluene, alcohol solvent and water is 1:2:0.5. The amount of halide is 3% of the molar amount of 3,4-(methylenedioxy)toluene, the amount of sulfonate anionic surfactant is 0.3% of the mass of the electrolyte, the electrolytic cell is made of PP, the cathode electrode is a Ti-based PbO2 electrode, and the anode electrode is a graphite electrode.

[0060] 2) After the electrolytic cell is heated to 60°C, current is passed through to react. The electrolytic cell voltage is 10V and the current density of the electrolytic cell is 2000A / m 2 The reaction was stopped after 10 hours of reaction, and the obtained reaction solution was distilled to remove alcohol solvents, halides and sulfonate anionic surfactant salts to obtain crude heliotropein, and finally ethanol was added for recrystallization to obtain finished heliotropein.

[0061] The H-NMR spectrum analysis data of heliotropin are as follows:

[0062] 1H NMR (300MHz, CDCl3): δ6.80-6.90(s,1H), δ7.30-7.40(d,1H), δ7.35-7.45(d,1H), δ5.95-6.05(s,2H), δ9.80-9.85(s,1H).

[0063] In this embodiment, the reaction solution was sampled and tested, wherein the conversion rate of the raw material 3,4-(methylenedioxy)toluene was 88.5%, the selectivity of the synthesized heliotropein was 85.3%, and the current efficiency was 79.3%.

[0064] Example 2

[0065] Electrochemical preparation of heliotropin, the steps are:

[0066] 1) Take 50g of 3,4-(methylenedioxy)toluene, 200g of ethanol, 20g of water, 1.09g of potassium bromide, 0.95g of sodium bromide and 1.36g of sodium dodecylbenzenesulfonate, mix them evenly, and add them to a diaphragmless electrolytic cell. The mass ratio of 3,4-(methylenedioxy)toluene, alcohol solvent and water is 1:4:0.4. The amount of halide is 5% of the molar amount of 3,4-(methylenedioxy)toluene, the amount of sulfonate anionic surfactant is 0.5% of the mass of the electrolyte, the electrolytic cell is made of PTFE, the cathode electrode is a graphite electrode, and the anode electrode is a Ti-based RuO2 electrode.

[0067] 2) After the electrolytic cell is heated to 50°C, current is passed through to react. The electrolytic cell voltage is 8V and the current density of the electrolytic cell is 1000A / m 2 The reaction was stopped after 20 hours of reaction, and the obtained reaction solution was distilled to remove alcohol solvents, halides and sulfonate anionic surfactant salts to obtain crude heliotropein, and finally ethanol was added for recrystallization to obtain finished heliotropein.

[0068] In this embodiment, the reaction solution was sampled and tested, wherein the conversion rate of the raw material 3,4-(methylenedioxy)toluene was 87.9%, the selectivity of the synthesized heliotropein was 86.2%, and the current efficiency was 80.1%.

[0069] Example 3

[0070] Electrochemical preparation of heliotropin, the steps are:

[0071] 1) Take 50g of 3,4-(methylenedioxy)toluene, 150g of propylene glycol, 15g of water, 0.61g of potassium iodide, 0.55g of sodium iodide and 1.72g of sodium α-olefin sulfonate, mix them evenly, and add them to a diaphragmless electrolytic cell. The mass ratio of 3,4-(methylenedioxy)toluene, alcohol solvent and water is 1:3:0.3. The amount of halide is 2% of the molar amount of 3,4-(methylenedioxy)toluene, the amount of sulfonate anionic surfactant is 0.8% of the mass of the electrolyte, the electrolytic cell is made of titanium, the cathode electrode is a Ti-based RuO2 electrode, and the anode electrode is a Ti-based IrO2 electrode.

[0072] 2) After the electrolytic cell is heated to 40°C, current is passed through to react. The electrolytic cell voltage is 7V and the current density is 800A / m 2 The reaction was stopped after 30 hours of reaction, and the obtained reaction solution was distilled to remove alcohol solvents, halides and sulfonate anionic surfactant salts to obtain crude jasminoids, and finally ethanol was added for recrystallization to obtain the finished jasminoids.

[0073] In this embodiment, the reaction solution was sampled and tested, wherein the conversion rate of the raw material 3,4-(methylenedioxy)toluene was 88.1%, the selectivity of the synthesized heliotropein was 86.6%, and the current efficiency was 79.2%.

[0074] Example 4

[0075] Electrochemical preparation of heliotropin, the steps are:

[0076] 1) Take 50g of 3,4-(methylenedioxy)toluene, 250g of propylene glycol, 5g of water, 0.35g of magnesium chloride and 3.05g of secondary alkyl sodium sulfonate, mix them evenly, and add them to a diaphragmless electrolytic cell. The mass ratio of 3,4-(methylenedioxy)toluene, alcohol solvent and water is 1:5:0.1. The amount of halide is 1% of the molar amount of 3,4-(methylenedioxy)toluene, the amount of sulfonate anionic surfactant is 1% of the mass of the electrolyte, the electrolytic cell is made of titanium, the cathode electrode is a Ti-based PbO2 electrode, and the anode electrode is a Ti-based IrO2 electrode.

[0077] 2) After the electrolytic cell is heated to 30°C, current is passed through to react. The electrolytic cell voltage is 6V and the current density of the electrolytic cell is 500A / m 2 The reaction was stopped after 40 hours of reaction, and the obtained reaction solution was distilled to remove alcohol solvents, halides and sulfonate anionic surfactant salts to obtain crude jasminoids, and finally ethanol was added for recrystallization to obtain finished jasminoids.

[0078] In this embodiment, the reaction solution was sampled and tested, wherein the conversion rate of the raw material 3,4-(methylenedioxy)toluene was 85.8%, the selectivity of the synthesized heliotropein was 86.5%, and the current efficiency was 78.8%.

[0079] Example 5

[0080] Electrochemical preparation of heliotropin, the steps are:

[0081] 1) 50 g of 3,4-(methylenedioxy)toluene, 200 g of methanol, 10 g of water, 0.34 g of magnesium bromide and 1.3 g of sodium hexadecyl diphenyl ether disulfonate were mixed uniformly and added to a diaphragmless electrolytic cell. The mass ratio of 3,4-(methylenedioxy)toluene, alcohol solvent and water was 1:4:0.2. The amount of halide was 0.5% of the molar amount of 3,4-(methylenedioxy)toluene, and the amount of sulfonate anionic surfactant was 0.5% of the mass of the electrolyte. The electrolytic cell was made of titanium, the cathode electrode was a Ti-based tin antimony oxide electrode, and the anode electrode was a Ti-based tin antimony oxide electrode.

[0082] 2) After the electrolytic cell is heated to 20°C, current is passed through to react. The electrolytic cell voltage is 7V and the current density of the electrolytic cell is 1500A / m 2 The reaction was stopped after 30 hours of reaction, and the obtained reaction solution was distilled to remove alcohol solvents, halides and sulfonate anionic surfactant salts to obtain crude jasminoids, and finally ethanol was added for recrystallization to obtain the finished jasminoids.

[0083] In this embodiment, the reaction solution was sampled and tested, wherein the conversion rate of the raw material 3,4-(methylenedioxy)toluene was 86.9%, the selectivity of the synthesized heliotropein was 86.1%, and the current efficiency was 80.4%.

[0084] Comparative Example 1

[0085] The electrochemical preparation method was carried out in accordance with Example 1, except that no halide (potassium chloride and sodium chloride) was added, and other operations and conditions remained unchanged.

[0086] In this comparative example, the reaction solution was sampled and tested, wherein the conversion rate of the raw material 3,4-(methylenedioxy)toluene was 42.7%, the selectivity of the synthesized heliotropein was 63.8%, and the current efficiency was 43.7%.

[0087] Comparative Example 2

[0088] The electrochemical preparation method was carried out in accordance with Example 1, except that sodium dodecylbenzenesulfonate was not added, and other operations and conditions remained unchanged.

[0089] In this comparative example, the reaction solution was sampled and tested, wherein the conversion rate of the raw material 3,4-(methylenedioxy)toluene was 68.9%, the selectivity of the synthesized heliotropin was 35.5%, and the current efficiency was 36.5%.

[0090] Comparative Example 3

[0091] The electrochemical preparation method was carried out in accordance with Example 1, except that sodium dodecylbenzenesulfonate was replaced with sodium dodecyl sulfate (a sulfate anionic surfactant), and other operations and conditions remained unchanged.

[0092] In this comparative example, the reaction solution was sampled and tested, wherein the conversion rate of the raw material 3,4-(methylenedioxy)toluene was 53.8%, the selectivity of the synthesized heliotropein was 48.2%, and the current efficiency was 46.1%.

Claims

1. An electrochemical preparation method of heliotropin, characterized in that: The following steps are involved: 1) mixing 3,4-(methylenedioxy)toluene, an alcohol solvent, water, a halide, and a sulfonate anionic surfactant to obtain an electrolyte, and adding the electrolyte to an electrolytic cell; 2) The electrolyte in the electrolytic cell of step 1) is energized to react, and 3,4-(methylenedioxy)toluene and an alcohol solvent are used to generate heliotropein at the anode.

2. The electrochemical preparation method according to claim 1, characterized in that: In step 1), the alcohol solvent is selected from C1-C3 alcohols, preferably any one of methanol, ethanol, and propylene glycol, or a combination of at least two thereof, more preferably methanol and / or ethanol.

3. The electrochemical preparation method according to claim 1 or 2, characterized in that: Step 1) The halide is a metal halide, preferably any one of metal chloride, metal bromide, and metal iodide, or a combination of at least two thereof, more preferably a metal bromide; Optionally, the halide is selected from any one or a combination of at least two of sodium chloride, potassium chloride, potassium bromide, sodium bromide, potassium iodide, sodium iodide, magnesium chloride, and magnesium bromide, preferably potassium bromide and / or sodium bromide.

4. The electrochemical preparation method according to any one of claims 1 to 3, characterized in that: In step 1), the sulfonate anionic surfactant is selected from any one or a combination of at least two of sodium dodecylbenzenesulfonate, sodium branched dodecylbenzenesulfonate, sodium α-olefinsulfonate, sodium secondary alkylsulfonate and sodium hexadecyldiphenylether disulfonate, preferably sodium α-olefinsulfonate and / or sodium secondary alkylsulfonate.

5. The electrochemical preparation method according to any one of claims 1 to 4, characterized in that: Step 1) The mass ratio of 3,4-(methylenedioxy)toluene, alcohol solvent and water added is 1:2-5:0.1-0.5, preferably 1:3-4:0.3-0.4; and / or Step 1) The amount of the halide added is 0.5-5% of the molar amount of 3,4-(methylenedioxy)toluene, preferably 1-3%; and / or In step 1), the amount of the sulfonate anionic surfactant salt added is 0.3-1%, preferably 0.5-0.8%, of the total mass of the electrolyte.

6. The electrochemical preparation method according to any one of claims 1 to 5, characterized in that: In step 2), the reaction temperature is 20-60°C, preferably 30-40°C; and the reaction time is 10-40h, preferably 20-30h.

7. The electrochemical preparation method according to any one of claims 1 to 6, characterized in that: In step 2), the electrolytic cell voltage range is 6-10V, preferably 7-8V; the current density is 500-2000A / m 2 , preferably 500-1000A / m 2 .

8. The electrochemical preparation method according to any one of claims 1 to 7, characterized in that: The electrolytic cell is a diaphragmless electrolytic cell; and / or The electrolytic cell is made of polypropylene, polytetrafluoroethylene or titanium, preferably titanium.

9. The electrochemical preparation method according to any one of claims 1 to 8, characterized in that: The electrolytic cell comprises an anode electrode and a cathode electrode; Optionally, the anode electrode and the cathode electrode are both selected from graphite electrodes or DSA electrodes, and the anode electrode and the cathode electrode may be the same or different; Preferably, the DSA electrode is any one of Ti-based PbO2, IrO2, RuO2 or tin antimony oxide electrodes.