Micro-reaction process and system for synthesizing muscone precursor by means of circulating flow electrolysis

Abstract

The present invention relates to the technical field of electrochemistry, relates to the electrochemical synthesis of a muscone precursor, and in particular to a micro-reaction process and system for synthesizing a muscone precursor by means of circulating flow electrolysis. An electrolysis micro-reactor is used to perform a circulating Kolbe electrolysis reaction on a raw material 1 and a raw material 2 in an electrolyte solution to synthesize dimethyl 3-methylpentadecanedioate. During the circulating Kolbe electrolysis reaction, an electrolyzed material discharged from the electrolysis micro-reactor is conveyed to a circulating solution storage tank to discharge a gas generated during electrolysis, and the electrolyzed material from which the gas has been discharged is then conveyed into the electrolysis micro-reactor again for an electrolysis reaction. The present invention shortens an ion conduction distance by means of a micro-channel structure of an electrolysis micro-reactor, promotes, by means of controllable circulating flow of an electrolyte solution, the timely discharge of a gas generated at an electrode, and reduces a cell voltage while the current density is guaranteed. The present invention has the characteristics of low energy consumption, concise process, and easy control.

Description

Micro-reaction process and system for synthesizing muscone precursor by cyclic flow electrolysis

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] The present application claims priority to the Chinese patent application No. 202410641700.2 filed on May 23, 2024, and entitled "Micro-reaction process and system for synthesizing muscone precursor by cyclic flow electrolysis", the content of which is incorporated herein by reference in its entirety and forms a part of this application for all purposes. TECHNICAL FIELD

[0003] The present application belongs to the technical field of electrochemistry, and relates to electrochemical synthesis of muscone precursor, in particular to a micro-reaction process and system for synthesizing muscone precursor by cyclic flow electrolysis. BACKGROUND

[0004] The information disclosed in this Background section is for the purpose of increasing the understanding of the general context of the present application and it may not necessarily be accepted as prior art with respect to this application.

[0005] There are three main methods for synthesizing muscone, namely, ring closure method, ring expansion method and methyl insertion method, among which the ring closure method is the main method for industrial production of muscone due to its advantages of wide raw material sources and mild reaction conditions.

[0006] 3-methyl pentadecane dimethyl ester is a precursor of muscone synthesized by the ring closure method, and its production level directly affects the quality and yield of muscone. 3-methyl pentadecane dimethyl ester is synthesized by Kolbe electrolysis reaction of dodecanedioic acid monomethyl ester (raw material 1) and β-methyl glutaric acid monomethyl ester (raw material 2) in an alkaline solution. The reaction mechanism is that raw material 1 and raw material 2 are oxidized and decarboxylated at the anode to form two carbon radicals, and the radicals dimerize to form a cross-coupling product, 3-methyl pentadecane dimethyl ester (1-2 for short), while hydrogen evolution occurs on the electrode. At present, the process for synthesizing 3-methyl pentadecane dimethyl ester by Kolbe electrolysis reaction is mainly implemented by using a tank electrolyzer. The inventors have found that the power consumption per unit mass of muscone precursor (1-2) is as high as 45.7 kW·h / kg or more in this process. At the same time, in the process of electrolyzing to prepare muscone precursor (1-2), the tank electrolyzer is prone to heat generation and even needs to be cooled by low-temperature chilled water, thereby further increasing the energy consumption of Kolbe electrolysis reaction for synthesizing muscone precursor (1-2). SUMMARY

[0007] The present application is to solve the problem of high energy consumption of Kolbe electrolysis reaction for synthesizing muscone precursor (1-2), and further research finds that under the condition of large current operation of Kolbe electrolysis reaction, a large amount of CO2 is generated at the anode, and a large amount of H2 is generated at the cathode, etc. A large amount of gas is very easy to accumulate near the electrode, thereby covering the electrode surface, reducing the utilization rate of the electrode, and increasing the solution resistance, so that a large amount of electrical energy is converted into heat and consumed. In addition, the generated heat is easy to make the temperature of the electrolysis reaction system rise, and even make the temperature of the electrolysis reaction system too high.

[0008] In order to solve the problems of the prior art, the purpose of the present application is to provide a circulating flow electrolysis micro-reaction process and system for synthesizing muscone precursor, which can greatly reduce the energy consumption of electrolysis synthesis of muscone precursor under the premise of ensuring the smooth progress of electrolysis reaction.

[0009] In order to achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0010] In a first aspect, a circulating flow electrolysis micro-reaction process for synthesizing muscone precursor is provided, which comprises an electrolysis micro-reactor and a circulating solution storage tank; the raw material 1 and the raw material 2 in the electrolyte solution are subjected to a circulating Kolbe electrolysis reaction to synthesize 3-methyl pentadecane diacid dimethyl ester by using the electrolysis micro-reactor;

[0011] In the process of the circulating Kolbe electrolysis reaction, the electrolyzed material discharged from the electrolysis micro-reactor is transported into the circulating solution storage tank to discharge the gas generated by electrolysis, and then the electrolyzed material after discharging gas is transported back into the electrolysis micro-reactor for electrolysis reaction;

[0012] The raw material 1 is dodecanedioic acid monomethyl ester; and the raw material 2 is beta-methyl glutaric acid monomethyl ester;

[0013] The solvent used in the electrolyte solution is one or a mixture of more than one of water, methanol, acetonitrile, dimethylformamide, dimethyl sulfoxide and ethylene glycol methyl ether;

[0014] The electrolyte in the electrolyte solution comprises an alkali.

[0015] The electrolysis micro-reactor in the present application is a micro-channel reactor capable of electrolysis, and the reaction system is carried out in the millimeter-level micro-channel of the micro-channel reactor. The present application obtains a low electrode spacing by means of micro-channel, reduces the ion conduction distance, utilizes the controllable circulating flow of the electrolyte solution, promotes the H2 and CO2 generated on the electrode in the electrolysis micro-reactor to circulate in time and be discharged in the circulating solution storage tank, reduces the cell voltage under the condition of ensuring the current density, and reduces the reaction energy consumption.

[0016] Further, the flow rate of the electrolyte solution flowing through the electrode surface in the electrolysis micro-reactor is not less than 0.01 m / s.

[0017] Further, the volume fraction of the gas phase in the electrolysis micro-reactor is not more than 20%.

[0018] Further, the electrolyte solution is heated to 30-60℃, and then is delivered to the electrolysis micro-reactor to perform the Kolbe electrolysis reaction.

[0019] Further, during the Kolbe electrolysis reaction, the reaction current density is 50-200 mA / cm 2 , and the voltage is 10-100 V.

[0020] Further, during the Kolbe electrolysis reaction, the molar concentration of the raw material 1 in the electrolyte solution is 0.35-0.6 mol / L, and the molar ratio of the raw material 1 to the raw material 2 is 0.9-1.1.

[0021] In the second aspect, a micro-reaction system for cyclic flow electrolysis synthesis of muscone precursor is used to realize the above micro-reaction process, and comprises:

[0022] The electrolysis micro-reactor is used to perform the Kolbe electrolysis reaction of the raw material 1 and the raw material 2 in the electrolyte solution to synthesize 3-methyl pentadecanedioic acid dimethyl ester.

[0023] The circulating solution storage tank is used to receive the electrolyte solution after the electrolysis reaction of the electrolysis micro-reactor, and discharge the electrolysis gas in the received electrolyte solution, and simultaneously provide the electrolyte solution for the Kolbe electrolysis reaction to the electrolysis micro-reactor.

[0024] The intermediate heat exchanger is used to heat the electrolyte solution to a temperature suitable for the Kolbe electrolysis reaction.

[0025] The circulating pump provides power for the flow of the electrolyte solution in the electrolysis micro-reactor, the circulating solution storage tank and the intermediate heat exchanger.

[0026] Further, the electrolysis micro-reactor comprises more than 10 parallel micro-channels, the channel width is 5-50 mm, the depth is 0.5-5 mm, the anode and the cathode are arranged alternately and in parallel inside the reactor, and the micro-channels are arranged in the middle of the parallel electrodes. The positive and negative electrode plates are arranged at both ends of the micro-channel width direction.

[0027] Further, the volume of the circulating solution storage tank is more than 100 times of the total volume of the micro-channels inside the electrolysis micro-reactor.

[0028] Further, the circulating solution storage tank is provided with a stirring device.

[0029] The beneficial effects of the present application are:

[0030] (1) The present application obtains low spacing between positive and negative electrode plates by means of microchannel structure of electrolysis microreactor, reduces ion conduction distance, reduces cell voltage caused by solution resistance; at the same time, the controlled circulation flow of electrolyte solution is used to promote H2 and CO2 generated on the electrode of electrolysis microreactor to be discharged in time, reduce cell voltage caused by gas accumulation near the electrode, reduce energy consumption under the condition of ensuring current density. Experiments show that under the operating condition of 100 mA / cm 2 The power consumption for producing unit 3-methyl pentadecanedioic acid dimethyl ester is less than 20 kW·h / kg, which is far lower than the energy consumption level of tank-type electrolytic cell.

[0031] (2) The present application is more conducive to controlling the uniformity of temperature and current distribution in the electrolytic cell compared with the relatively disordered flow state in the tank-type electrolysis system, which is conducive to the controllable progress of electrolysis reaction and the extension of electrode life. BRIEF DESCRIPTION OF DRAWINGS

[0032] The accompanying drawings, which form a part of this specification, are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification. The embodiments of the application, and their

[0033] Figure 1 is a schematic diagram of a microreaction system for cyclic electrolysis synthesis of 3-methyl pentadecanedioic acid dimethyl ester in the embodiment of the present application;

[0034] Among them, 1. electrolysis microreactor, 2. direct current power supply, 3. circulating solution storage tank, 4. circulating pump, 5. intermediate heat exchanger, 6. condenser, 7. feed inlet, 8. discharge port, 9. gas phase outlet. DETAILED DESCRIPTION

[0035] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0036] It should be noted that the terms used herein are only for the purpose of describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form, and in addition, it should be understood that when the terms "comprise" and / or "include" are used in the specification, they mean the presence of a feature, step, operation, device, component and / or combination thereof.

[0037] At the same time, "one or more" means any one of the listed items or any combination of the listed items, unless otherwise specified. Similarly, "one or more" and other expressions of "one or more" are interpreted in the same way, unless otherwise specified.

[0038] In addition, unless otherwise specified, "further", "furthermore", "in particular", "for example", "such as", "for instance", "for example", etc. are used for description purposes, indicating that the different technical solutions before and after are related in terms of coverage, but should not be understood as a limitation of the previous technical solution, nor as a limitation of the scope of protection herein.

[0039] In view of the problem of high energy consumption in synthesizing muscone precursor by existing Kolbe electrolysis reaction, the present application provides a micro-reaction process and system for synthesizing muscone precursor by circulating flow electrolysis.

[0040] In a typical embodiment of the present application, a micro-reaction process for synthesizing muscone precursor by circulating flow electrolysis is provided, which provides an electrolysis micro-reactor and a circulating solution storage tank; raw material 1 and raw material 2 in the electrolyte solution are subjected to a circulating Kolbe electrolysis reaction to synthesize 3-methyl pentadecane diacid dimethyl ester by using the electrolysis micro-reactor;

[0041] In the process of circulating Kolbe electrolysis reaction, the electrolyzed material discharged from the electrolysis micro-reactor is transported into the circulating solution storage tank to discharge the gas generated by electrolysis, and then the electrolyzed material after discharging gas is transported back into the electrolysis micro-reactor for electrolysis reaction;

[0042] The raw material 1 is dodecanedioic acid monomethyl ester; and the raw material 2 is beta-methyl glutaric acid monomethyl ester.

[0043] Although the present application research shows that CO2 and H2 generated by Kolbe electrolysis reaction are the main reasons affecting its energy consumption, experiments show that only by setting an external circulation mode to discharge the gas generated by electrolysis reaction, the problem of high power consumption cannot be solved. The purpose of using a micro-reactor in the traditional method is to improve the heat and mass transfer efficiency, but experiments show that only using an electrolysis micro-reactor cannot realize the preparation of 3-methyl pentadecane diacid dimethyl ester by Kolbe electrolysis reaction. The present application reduces the cell voltage by using an electrolysis micro-reactor and simultaneously setting an external circulation and discharging gas in time, so as to realize a significant reduction in energy consumption.

[0044] In some embodiments, the electrolyte solution flowing over the electrode surface in the electrolysis micro-reactor has a flow rate of no less than 0.01 m / s. It can be 0.01 m / s, 0.02 m / s, 0.03 m / s, 0.04 m / s, 0.05 m / s, 0.06 m / s, 0.07 m / s, 0.08 m / s, 0.09 m / s, 0.10 m / s, 0.11 m / s, 0.12 m / s, 0.13 m / s, 0.14 m / s, 0.15 m / s, 0.16 m / s, 0.17 m / s, 0.18 m / s, 0.19 m / s, 0.20 m / s, or a range between any two of the above values, preferably 0.01-0.10 m / s. Under this condition, the generated H2 and CO2 can be timely discharged and the raw material can be fully reacted.

[0045] In some embodiments, the volume fraction of the gas phase in the electrolysis micro-reactor is no more than 20%. The volume fraction of the gas phase can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20%. Under this condition, the raw material can be more fully subjected to the Kolbe electrolysis reaction.

[0046] In some embodiments, the electrolyte solution is heated to 30-60°C and then fed into the electrolysis micro-reactor for the Kolbe electrolysis reaction. The Kolbe electrolysis reaction is best performed at a temperature of 30-60°C (e.g., 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, etc.).

[0047] In some embodiments, the reaction current density during the Kolbe electrolysis reaction is 50-200 mA / cm 2 , and the voltage is 10-100 V. The reaction current density can be 50 mA / cm 2 , 60 mA / cm 2 , 70 mA / cm 2 , 80 mA / cm 2 , 90 mA / cm 2 , 100 mA / cm 2 , 110 mA / cm 2 , 120 mA / cm 2 , 130 mA / cm 2 , 140 mA / cm 2 , 150 mA / cm 2 , 160 mA / cm 2 , 170 mA / cm 2 , 180 mA / cm 2 , 190 mA / cm 2200mA / cm 2 The voltage can be 10V, 20V, 30V, 40V, 50V, 60V, 70V, 80V, 90V, or 100V, or the range between any two points.

[0048] In some embodiments, during the Kolbe electrolysis reaction, the molar concentration of raw material 1 in the electrolyte solution is 0.35–0.6 mol / L, and the molar ratio of raw material 1 to raw material 2 is 0.9–1.1. The molar concentration of raw material 1 can be 0.35 mol / L, 0.36 mol / L, 0.37 mol / L, 0.38 mol / L, 0.39 mol / L, 0.40 mol / L, 0.41 mol / L, 0.42 mol / L, 0.43 mol / L, 0.44 mol / L, 0.45 mol / L, 0.46 mol / L, 0.47 mol / L, 0.48 mol / L, 0.49 mol / L, 0.50 mol / L, 0.51 mol / L, 0.52 mol / L, 0.53 mol / L, 0.54 mol / L, 0.55 mol / L, 0.56 mol / L, 0.57 mol / L, 0.58 mol / L, 0.59 mol / L, 0.6 mol / L, or any range between two points.

[0049] Specifically, the solvent used in the electrolyte solution is one or more of water, methanol, acetonitrile, dimethylformamide, dimethyl sulfoxide, and ethylene glycol methyl ether.

[0050] Specifically, the electrolyte in the electrolyte solution includes a base. The base described in this invention is an alkali metal (e.g., potassium metal, sodium metal, etc.) or an alkaline compound of an alkali metal (e.g., sodium hydroxide, potassium hydroxide, sodium methoxide, etc.). More specifically, the molar amount of the base is 5-25% of the total molar amount of raw materials 1 and 2.

[0051] Another embodiment of the present invention provides a microreaction system for the cyclic electrolytic synthesis of muscone precursors, used to implement the above-mentioned microreaction process, comprising:

[0052] An electrolytic microreactor is used to synthesize dimethyl 3-methylpentadecanedioate by Kolbe electrolysis of raw material 1 and raw material 2 in an electrolyte solution.

[0053] A circulating solution storage tank is used to receive the electrolyte solution after the electrolysis reaction in the electrolysis microreactor, and to discharge the gas generated by electrolysis in the received electrolyte solution, while providing the electrolysis microreactor with the electrolyte solution for the Kolbe electrolysis reaction;

[0054] An intermediate heat exchanger for heating the electrolyte solution to a temperature suitable for the Kolbe electrolysis reaction;

[0055] A circulating pump for providing power for the flow of the electrolyte solution in the electrolysis micro-reactor, the circulating solution storage tank and the intermediate heat exchanger.

[0056] In some embodiments, the electrolysis micro-reactor comprises more than 10 parallel micro-channels, with a width of 5-50 mm and a depth of 0.5-5 mm. The anode and cathode are arranged alternately and in parallel inside the reactor, and the micro-channels are arranged between the parallel electrodes. The micro-channels are arranged between the two electrodes, i.e. the two electrodes are arranged close to the two opposite side walls of the micro-channels.

[0057] In some embodiments, the volume of the circulating solution storage tank is more than 100 times the total volume of the micro-channels inside the electrolysis micro-reactor.

[0058] In some embodiments, the circulating solution storage tank is provided with a stirring device. Specifically, the stirring device comprises a stirring motor and a stirring paddle, and the stirring motor is connected to the stirring paddle and drives the stirring paddle to rotate.

[0059] Specifically, the circulating solution storage tank is provided with an electrolyte solution inlet, an electrolyte solution outlet, a gas phase outlet, a feed inlet and a discharge outlet. The feed inlet is used to fill the electrolyte solution, and the discharge outlet is used to empty the material after the reaction is completed. The gas phase outlet of the circulating solution storage tank is connected to a condenser for cooling the discharged gas to avoid carrying out the solvent.

[0060] In order to enable those skilled in the art to more clearly understand the technical solutions of the present application, the technical solutions of the present application will be described in detail below in combination with specific examples and comparative examples.

[0061] The system used in the following examples is shown in Figure 1, which mainly comprises an electrolysis micro-reactor 1, a circulating solution storage tank 3, a circulating pump 4, an intermediate heat exchanger 5 connected in sequence, and the outlet of the intermediate heat exchanger 5 is connected to the inlet of the electrolysis micro-reactor 1. The circulating solution storage tank 3 is provided with a condenser 6 at the top. The outlet of the condenser 6 is connected to the gas phase outlet 9 of the system. The discharge outlet at the bottom of the circulating solution storage tank is connected to the discharge outlet 8 of the system. The electrolysis micro-reactor 1 is connected to a direct current power supply 2. The feed inlet 7 of the system is connected to the feed inlet of the circulating solution storage tank 3.

[0062] Example 1

[0063] Under stirring, 1.62 kg (0.350 mol / L) of raw material 1, 1.03 kg (0.34 mol / L) of raw material 2, 40 g (0.090 mol / L) of sodium metal, 19 L of methanol were added into the circulating solution storage tank. The intermediate heat exchanger and the circulating pump were started to deliver the electrolyte solution in the circulating solution storage tank into the microreactor (containing 12 parallel microchannels) with a channel size of 50 mm x 2 mm (width x depth), the flow rate in the microreactor was controlled at 0.04 m / s, and the material temperature was controlled in the range of 50 ± 3 °C. The gas phase outlet gas was condensed to below 25 °C by the condenser on the top of the storage tank. The power supply was turned on, and the reaction was started, the reaction current was controlled at 100 mA / cm 2 , the electrolysis voltage was 35.0 V, and the gas phase volume fraction was about 10%. After the reaction was completed, the power supply, the condenser, and the intermediate heat exchanger were turned off, and the material was discharged through the discharge port of the circulating solution storage tank. The power consumption per unit mass of muscone precursor (1-2) was 20.0 kW·h / kg.

[0064] Example 2

[0065] Under stirring, 1.62 kg (0.350 mol / L) of raw material 1, 1.03 kg (0.34 mol / L) of raw material 2, 40 g (0.090 mol / L) of sodium metal, 19 L of methanol were added into the circulating solution storage tank. The intermediate heat exchanger and the circulating pump were started to deliver the electrolyte solution in the circulating solution storage tank into the microreactor (containing 12 parallel microchannels) with a channel size of 50 mm x 2 mm (width x depth), the flow rate in the microreactor was controlled at 0.04 m / s, and the material temperature was controlled in the range of 50 ± 3 °C. The gas phase outlet gas was condensed to below 25 °C by the condenser on the top of the storage tank. The power supply was turned on, and the reaction was started, the reaction current was controlled at 100 mA / cm 2 , the electrolysis voltage was 35.0 V, and the gas phase volume fraction was about 10%. After the reaction was completed, the power supply, the condenser, and the intermediate heat exchanger were turned off, and the material was discharged through the discharge port of the circulating solution storage tank. The power consumption per unit mass of muscone precursor (1-2) was 20.0 kW·h / kg.

[0066] Example 3

[0067] Under stirring, 11.73 g (0.480 mol / L) of raw material 1, 7.68 g (0.480 mol / L) of raw material 2, 0.6 g (0.100 mol / L) of sodium methoxide, 100 mL of methanol were added into the circulating solution storage tank. The intermediate heat exchanger and the circulating pump were started to deliver the electrolyte solution in the circulating solution storage tank into the microreactor (containing 12 parallel microchannels) with a channel size of 5 mm x 1 mm (width x depth), the flow rate in the microreactor was controlled at 0.08 m / s, and the material temperature was controlled in the range of 50 ± 3 °C. The gas phase outlet gas was condensed to below 25 °C by the condenser on the top of the storage tank. The power supply was turned on, and the reaction was started, the reaction current was controlled at 200 mA / cm 2 , the electrolysis voltage was 34.9 V, and the gas phase volume fraction was about 7%. After the reaction was completed, the power supply, the condenser, and the intermediate heat exchanger were turned off, and the material was discharged through the discharge port of the circulating solution storage tank. The power consumption per unit mass of muscone precursor (1-2) was 19.2 kW·h / kg.

[0068] Example 4

[0069] Under stirring, 3.36 kg (0.550 mol / L) of raw material 1, 2.00 kg (0.500 mol / L) of raw material 2, 101 g (0.075 mol / L) of sodium methoxide, 25 L of methanol were added into the circulating solution storage tank. The intermediate heat exchanger and the circulating pump were started to deliver the electrolyte solution in the circulating solution storage tank into the microreactor (containing 13 parallel microchannels) with a channel size of 50 mm x 2 mm (width x depth), the flow rate in the microreactor was controlled at 0.04 m / s, and the material temperature was controlled in the range of 45 ± 3 °C. The gas phase outlet gas was condensed to below 25 °C by the condenser on the top of the storage tank. The power supply was turned on, and the reaction was started, the reaction current was controlled at 200 mA / cm 2 , the electrolysis voltage was 32.5 V, and the gas phase volume fraction was about 13%. After the reaction was completed, the power supply, the condenser, and the intermediate heat exchanger were turned off, and the material was discharged through the discharge port of the circulating solution storage tank. The power consumption per unit mass of muscone precursor (1-2) was 17.4 kW·h / kg.

[0070] Example 5

[0071] Under stirring, 672 g (0.550 mol / L) of raw material 1, 400 g (0.500 mol / L) of raw material 2, 11.5 g (0.100 mol / L) of sodium metal, 5 L of methanol were added into the circulating solution storage tank. The intermediate heat exchanger and the circulating pump were started to deliver the electrolyte solution in the circulating solution storage tank into the microreactor (containing 13 parallel microchannels) with a channel size of 25 mm x 2 mm (width x depth), the flow rate in the microreactor was controlled at 0.04 m / s, and the material temperature was controlled in the range of 40 ± 3 °C. The top of the storage tank was started to pass through the condenser to condense the gas phase outlet gas to below 25 °C for discharge. The power supply was turned on to start the reaction, and the reaction current was controlled at 100 mA / cm 2 , the electrolysis voltage was 34.1 V, and the gas phase volume content was about 14%. After the reaction was completed, the power supply, the condenser, and the intermediate heat exchanger were turned off, and the material was discharged through the discharge port of the circulating solution storage tank. The power consumption per unit mass of muscone precursor (1-2) was 19.0 kW·h / kg.

[0072] Example 6

[0073] Under stirring, 336 g (0.550 mol / L) of raw material 1, 200 g (0.500 mol / L) of raw material 2, 15 g (0.150 mol / L) of sodium hydroxide, 2 L of acetonitrile, and 0.5 L of water were added into the circulating solution storage tank. The intermediate heat exchanger and the circulating pump were started to deliver the electrolyte solution in the circulating solution storage tank into the microreactor (containing 14 parallel microchannels) with a channel size of 25 mm x 5 mm (width x depth), the flow rate in the microreactor was controlled at 0.01 m / s, and the material temperature was controlled in the range of 40 ± 3 °C. The top of the storage tank was started to pass through the condenser to condense the gas phase outlet gas to below 25 °C for discharge. The power supply was turned on to start the reaction, and the reaction current was controlled at 100 mA / cm 2 , the electrolysis voltage was 30.8 V, and the gas phase volume content was about 17%. After the reaction was completed, the power supply, the condenser, and the intermediate heat exchanger were turned off, and the material was discharged through the discharge port of the circulating solution storage tank. The power consumption per unit mass of muscone precursor (1-2) was 16.6 kW·h / kg.

[0074] Example 7

[0075] Under stirring, 9.76 g (0.400 mol / L) of raw material 1, 6.40 g (0.400 mol / L) of raw material 2, 0.2 g (0.050 mol / L) of sodium hydroxide, 100 mL of dimethyl sulfoxide were added into the circulating solution storage tank. The intermediate heat exchanger and the circulating pump were started to deliver the electrolyte solution in the circulating solution storage tank into the microreactor (containing 14 parallel microchannels) with a channel size of 5 mm x 1 mm (width x depth), the flow rate in the microreactor was controlled at 0.08 m / s, and the material temperature was controlled in the range of 40 ± 3 ℃. The top of the storage tank was started to pass through the condenser to condense the gas phase outlet gas to below 25 ℃ for discharge. The power supply was turned on to start the reaction, the reaction current was controlled at 100 mA / cm 2 , the electrolysis voltage was 20.4 V, and the gas phase volume content was about 14%. After the reaction was completed, the power supply, the condenser, and the intermediate heat exchanger were turned off, and the material was discharged through the discharge port of the circulating solution storage tank. The power consumption per unit mass of muscone precursor (1-2) was 11.4 kW·h / kg.

[0076] Example 8

[0077] Under stirring, 9.76 g (0.400 mol / L) of raw material 1, 6.40 g (0.400 mol / L) of raw material 2, 0.2 g (0.050 mol / L) of sodium hydroxide, 20 mL of water, 60 mL of methanol, and 20 mL of dimethylformamide were added into the circulating solution storage tank. The intermediate heat exchanger and the circulating pump were started to deliver the electrolyte solution in the circulating solution storage tank into the microreactor (containing 14 parallel microchannels) with a channel size of 5 mm x 1 mm (width x depth), the flow rate in the microreactor was controlled at 0.08 m / s, and the material temperature was controlled in the range of 40 ± 3 ℃. The top of the storage tank was started to pass through the condenser to condense the gas phase outlet gas to below 25 ℃ for discharge. The power supply was turned on to start the reaction, the reaction current was controlled at 100 mA / cm 2 , the electrolysis voltage was 21.6 V, and the gas phase volume content was about 14%. After the reaction was completed, the power supply, the condenser, and the intermediate heat exchanger were turned off, and the material was discharged through the discharge port of the circulating solution storage tank. The power consumption per unit mass of muscone precursor (1-2) was 12.1 kW·h / kg.

[0078] Comparative Example 1

[0079] The implementation method of the present comparative example is basically the same as that of Example 1, except that the microreaction system described in the present application is not used, that is, a general tank-type electrolytic cell is used. The specific steps are as follows:

[0080] Under stirring, 1.62 kg (0.350 mol / L) of raw material 1, 1.03 kg (0.34 mol / L) of raw material 2, 40 g (0.090 mol / L) of metallic sodium, and 19 L of methanol were added into the tank electrolyzer, and mechanical stirring was set. The temperature of the materials in the tank was controlled in the range of 50 ± 3 °C by using the ethylene glycol condensation coil. The gas phase outlet gas was condensed to below 25 °C by the condenser at the top of the tank electrolyzer. The power was turned on, and the reaction was started. The reaction current was controlled at 100 mA / cm 2 , and the electrolysis voltage was 62.0 V. After the reaction was completed, the power, the condenser, and the electrolyte solution were turned off, and the materials were discharged through the discharge port of the tank electrolyzer. The power consumption per unit mass of muscone precursor (1-2) was 45.7 kW·h / kg.

[0081] Comparative Example 2

[0082] The implementation method of the present comparative example was basically the same as that of Example 1, except that the flow rate in the microreactor was controlled at 0.005 m / s. The specific steps were as follows:

[0083] Under stirring, 1.62 kg (0.350 mol / L) of raw material 1, 1.03 kg (0.34 mol / L) of raw material 2, 40 g (0.090 mol / L) of metallic sodium, and 19 L of methanol were added into the tank electrolyzer, and mechanical stirring was set. The temperature of the materials in the tank was controlled in the range of 50 ± 3 °C by using the ethylene glycol condensation coil. The gas phase outlet gas was condensed to below 25 °C by the condenser at the top of the tank electrolyzer. The power was turned on, and the reaction was started. The reaction current was controlled at 100 mA / cm 2 , and the electrolysis voltage was 62.0 V. After the reaction was completed, the power, the condenser, and the electrolyte solution were turned off, and the materials were discharged through the discharge port of the tank electrolyzer. The power consumption per unit mass of muscone precursor (1-2) was 45.7 kW·h / kg.

[0084] Comparative Example 3

[0085] The implementation method of the present comparative example was basically the same as that of Example 1, except that the electrolyte flowing through the microreactor was not circulated back to the circulating solution storage tank. The specific steps were as follows:

[0086] Under stirring, 1.62 kg (0.350 mol / L) of raw material 1, 1.03 kg (0.34 mol / L) of raw material 2, 40 g (0.090 mol / L) of metallic sodium, and 19 L of methanol were added into the circulating solution storage tank. The intermediate heat exchanger and the circulating pump were started to transport the electrolyte solution in the raw material solution storage tank into the microreactor with a channel size of 50 mm x 2 mm (width x depth), and the outlet of the microreactor was connected to the product solution storage tank. The flow rate in the microreactor was controlled to be 0.04 m / s, and the material temperature was controlled to be in the range of 45 ± 3 °C. The top of the storage tank was connected to a condenser to condense the gas phase outlet gas to below 25 °C for discharge. The power supply was turned on, and the reaction was started. The reaction current was controlled to be 100 mA / cm 2 , the electrolysis voltage was 35.0 V, and the gas phase volume fraction was about 15%. The results were consistent with those of Example 1. After the reaction was completed, the power supply, the condenser, and the intermediate heat exchanger were turned off, and the material was discharged through the product solution storage tank discharge port. Since the electrolyte solution only passed through the storage tank once, the raw material conversion rate was less than 1%, and the product concentration in the product solution was lower than the detection limit of liquid chromatography.

[0087] Comparative Example 4

[0088] The implementation method of the present comparative example was basically the same as that of Comparative Example 1, except that the outlet of the tank electrolysis cell was connected to a circulating pump, and the outlet of the circulating pump was connected to the inlet of the tank electrolysis cell to circulate the liquid in the tank electrolysis cell in the pipeline. The specific implementation steps were as follows:

[0089] Under stirring, 1.62 kg (0.350 mol / L) of raw material 1, 1.03 kg (0.34 mol / L) of raw material 2, 40 g (0.090 mol / L) of metallic sodium, and 19 L of methanol were added into the tank electrolysis cell. Mechanical stirring was provided in the electrolysis cell, and the ethylene glycol condensation coil was used to control the material temperature in the tank to be in the range of 45 ± 3 °C. The outlet of the tank electrolysis cell was connected to a circulating pump, and the outlet of the circulating pump was connected to the inlet of the tank electrolysis cell to circulate the liquid in the tank electrolysis cell in the pipeline. The top of the tank electrolysis cell was connected to a condenser to condense the gas phase outlet gas to below 25 °C for discharge. The power supply was turned on, and the reaction was started. The reaction current was controlled to be 100 mA / cm 2 , and the electrolysis voltage was 62.0 V. The results were consistent with those of Comparative Example 1. After the reaction was completed, the power supply, the condenser, and the tank electrolysis cell were turned off, and the material was discharged through the tank electrolysis cell discharge port. The power consumption per unit mass of muscone precursor (1-2) was 45.7 kW·h / kg, which was consistent with that of Comparative Example 1.

[0090] The raw material ratio parameters in the preparation methods of Examples 1 to 8 and Comparative Examples 1 to 4 are listed in Table 1 below.

[0091] Table 1: Parameters and power consumption in the preparation method

[0092] The above merely provides the preferred embodiments of the present application, and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the principles and technical scope of the present application shall fall into the scope of the present application.

Claims

1. A microreactor process for the cyclic flow electro-synthesis of muscone precursors, characterized in that, The application provides an electrolysis micro-reactor, a circulating solution storage tank, an intermediate heat exchanger and a circulating pump; the raw material 1 and the raw material 2 in an electrolyte solution are subjected to a cyclic Kolbe electrolysis reaction to synthesize 3-methyl pentadecane diacid dimethyl ester by using the electrolysis micro-reactor; the electrolysis micro-reactor comprises more than 10 parallel micro-channels, the width of the micro-channels is 5-50 mm, the depth of the micro-channels is 0.5-5 mm, the anode and the cathode are arranged alternately and in parallel in the reactor, and the micro-channels are arranged in the middle of the parallel electrodes; The circulating solution storage tank is used for receiving the electrolyte solution after the electrolysis reaction of the electrolysis micro-reactor, discharging the gas generated in the electrolysis of the received electrolyte solution, and providing the electrolyte solution for the Kolbe electrolysis reaction to the electrolysis micro-reactor; The intermediate heat exchanger is used for heating the electrolyte solution to a temperature suitable for the Kolbe electrolysis reaction; The circulating pump provides power for the flow of the electrolyte solution in the electrolysis micro-reactor, the circulating solution storage tank and the intermediate heat exchanger; During the cyclic Kolbe electrolysis reaction, the electrolysis material discharged from the electrolysis micro-reactor is transported into the circulating solution storage tank to discharge the gas generated in the electrolysis, and then the electrolysis material after discharging the gas is transported into the electrolysis micro-reactor to perform the electrolysis reaction; The raw material 1 is dodecanedioic acid monomethyl ester; the raw material 2 is beta-methyl glutaric acid monomethyl ester; The solvent used in the electrolyte solution is one or more mixtures of water, methanol, acetonitrile, dimethylformamide, dimethyl sulfoxide and ethylene glycol methyl ether; The electrolyte in the electrolyte solution comprises a base; The base is selected from one or more of sodium hydroxide, potassium hydroxide or sodium methoxide; the molar amount of the base is 5-25% of the total molar amount of the raw materials 1 and 2; The volume content rate of the gas phase in the electrolysis micro-reactor is not more than 20%; The reaction current density is 50-200 mA / cm 2 , and the voltage is 10-100 V.

2. The microreactor process for cyclic flow electrolysis synthesis of musk ketone precursor according to claim 1, characterized in that, The flow velocity of the electrolyte solution flowing through the electrode surface in the electrolysis micro-reactor is not less than 0.01 m / s.

3. The microreactor process for cyclic flow electrolysis synthesis of musk ketone precursor according to claim 1, characterized in that, The electrolyte solution is heated to 30-60 DEG C and then transported into the electrolysis micro-reactor to perform the Kolbe electrolysis reaction.

4. The microreactor process for cyclic flow electrolysis synthesis of musk ketone precursor according to claim 1, characterized in that, During the Kolbe electrolysis reaction, the molar concentration of the raw material 1 in the electrolyte solution is 0.35-0.6 mol / L, and the molar ratio of the raw material 1 to the raw material 2 is 0.9-1.

1.

5. The microreactor process for cyclic flow electrolysis synthesis of musk ketone precursor according to claim 1, characterized in that, The volume of the circulating solution storage tank is more than 100 times of the total volume of the micro-channels in the electrolysis micro-reactor.

6. The microreactor process for cyclic flow electrolysis synthesis of musk ketone precursor according to claim 1, characterized in that, A stirring device is arranged in the circulating solution storage tank.

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