Continuous production process of dimethyl sulfoxide

Abstract

The invention discloses a continuous production process of dimethyl sulfoxide, which comprises a hydrogen peroxide storage tank, a mass flow meter, a delivery pump, a micro-channel reactor, a dimethyl sulfide storage tank, a flow self-control valve, a thermometer, a pressure gauge, a cold and hot all-in-one machine, a sampling port, a multi-phase reactor, a liquid level meter, a phase splitter, an electromagnetic valve, a dimethyl sulfoxide storage tank and a water phase storage tank. Outlets of the hydrogen peroxide storage tank and the dimethyl sulfide storage tank are respectively connected to a micro-channel reactor through a mass flow meter and a delivery pump, an outlet of the micro-channel reactor is connected to a multi-phase reactor, the micro-channel reactor and the multi-phase reactor are respectively connected to a cold and hot all-in-one machine, the multi-phase reactor is connected to a phase splitter, and the phase splitter is connected to a hot and cold all-in-one machine. And the phase splitter is respectively connected to a dimethyl sulfoxide storage tank and a water phase storage tank. According to the invention, the continuous production of dimethyl sulfoxide can be realized, the problems of low production efficiency and high production cost in the existing dimethyl sulfoxide production process are solved, and the production safety is ensured.

Description

Technical Field

[0001] The present invention relates to the field of chemical equipment, and particularly to a continuous production process of dimethyl sulfoxide. Technical Background

[0002] Dimethyl sulfoxide is a sulfur-containing polar organic solvent and has a wide range of applications in the chemical field. It can be used as a dyeing solvent, decolorizing agent, dyeing carrier for synthetic fibers, and an absorbent for recovering acetylene and sulfur dioxide. Its preparation methods include the methanol carbon disulfide method, the hydrogen peroxide method, and the nitrogen dioxide method. Currently, the nitrogen dioxide oxidation method is mostly used in industry to produce dimethyl sulfoxide. Using dimethyl sulfide as the raw material and hydrogen peroxide as the oxidant, dimethyl sulfoxide is synthesized by optimizing process conditions such as material ratio and temperature. The by-product is water, and the product is easy to purify, enabling the green and clean production of dimethyl sulfoxide.

[0003] Patent CN114890924B discloses a preparation method of dimethyl sulfoxide. Dimethyl sulfide and hydrogen peroxide are transported into a mixer by metering pumps and sequentially pass through a first to sixth-stage tubular reactor. The first-stage tubular reactor jacket is equipped with a hot water pipeline, and the reaction is carried out by controlling the temperature. The unreacted dimethyl sulfide and hydrogen peroxide are sequentially reacted completely in the second to sixth-stage tubular reactors. The reaction conditions are mild and no hazardous waste is generated, which is environmentally friendly. However, the mixing effect is poor, and the two materials cannot be fully contacted and mixed. Patent CN114805145A provides a synthesis process of dimethyl sulfoxide. Using dimethyl sulfide as the raw material and hydrogen peroxide as the oxidant, the two materials are first passed into a membrane mixer to make them fully contact and mix, and then sent into a continuous flow microreactor to produce dimethyl sulfoxide. This method ensures the full reaction of dimethyl sulfide and hydrogen peroxide, but the production efficiency is low, the cost of producing dimethyl sulfoxide is high, and it is not suitable for large-scale production.

[0004] In summary, there is an urgent need for a new type of efficient synthesis method with full contact and mixing to solve the problems of low production efficiency, complex process, and high production cost in the existing production process of dimethyl sulfoxide. And solve the problem of large heat release during the production process to ensure production safety. Summary of the Invention

[0005] To solve the problems of high cost, high energy consumption, insufficient production capacity, and poor safety in the existing production process of dimethyl sulfoxide, the present invention provides a continuous production process of dimethyl sulfoxide.

[0006] The technical means adopted by the present invention are as follows: A continuous production process of dimethyl sulfoxide, including a hydrogen peroxide storage tank, a mass flowmeter A, a transfer pump A, a microchannel reactor, a dimethyl sulfide storage tank, a mass flowmeter B, a transfer pump B, a flow control valve A, a flow control valve B, a thermometer A, a pressure gauge A, a cooling and heating integrated machine A, a sampling port A, a multiphase reactor, a thermometer B, a pressure gauge B, a cooling and heating integrated machine B, a sampling port B, a liquid level gauge, a phase separator, a solenoid valve, a dimethyl sulfoxide storage tank, and an aqueous phase storage tank. The above hydrogen peroxide storage tank is divided into three branches through the mass flowmeter A and the transfer pump A and respectively connected to the microchannel reactor. After the above branch nodes, the flow control valve A and the flow control valve B are respectively set. The above dimethyl sulfide storage tank is connected to the microchannel reactor through the mass flowmeter B and the transfer pump B. The above microchannel reactor is provided with a thermometer A and a pressure gauge A and is connected to the cooling and heating integrated machine A through an oil outlet pipe and a return pipe. The above microchannel reactor is connected to the multiphase reactor through the sampling port A. The above multiphase reactor is provided with a thermometer A and a pressure gauge A and is connected to the cooling and heating integrated machine B through an oil outlet pipe and a return pipe. The above multiphase reactor is connected to the phase separator through the sampling port B. The above phase separator is provided with a liquid level gauge. One branch of the above phase separator is connected to the dimethyl sulfoxide storage tank through a solenoid valve. The other branch of the above phase separator is connected to the aqueous phase storage tank.

[0007] Further, the above microchannel reactor is composed of six plates connected in series. The three branches connecting the hydrogen peroxide storage tank and the microchannel reactor respectively enter the 1st, 3rd, and 5th plates. The flow rate of hydrogen peroxide is controlled by the flow control valve A and the flow control valve B. The 1st plate enters 40%-60% of the total flow rate, the 3rd plate enters 20%-40% of the total flow rate, and the 5th plate enters 0%-20% of the total flow rate.

[0008] Further, the molar ratio of the above reaction materials (hydrogen peroxide: dimethyl sulfide) is 1:1.05 - 1:5, and the preferred ratio is 1:1 - 1:2; the reaction temperature is 30 - 100 °C, the preferred temperature is 40 - 70 °C, the residence time is 0.5 - 30 min, and the preferred residence time is 1 - 20 min.

[0009] Further, the above multiphase reactor has a "double heat exchange" structure. The stirring shaft is hollow and passes through a heat exchange fluid, which together with the jacket realizes the heat exchange of the reaction, can improve the heat exchange efficiency, avoid the danger caused by local overheating, and improve the safety of production;

[0010] Further, the reaction chamber tube length of the above multiphase reactor is much larger than the tube diameter, and the length-diameter ratio is about 5 - 20. The radial thickness of the reaction materials is 10 mm - 300 mm. Baffles and closely arranged stirring paddles are arranged in the reaction chamber, strengthening the mass transfer and heat transfer effects of the materials and improving the product quality.

[0011] Since the present invention adopts the above technical solutions, the technical effects produced are obvious:

[0012] 1. Dimethyl sulfide and hydrogen peroxide react to release a large amount of heat. Hydrogen peroxide enters the microchannel reactor through three branches to achieve segmented feeding and heat extraction, which improves the stability of the reaction and the safety of production;

[0013] 2. A solenoid valve is set at the outlet of the phase separator to control the entry of dimethyl sulfoxide into the dimethyl sulfoxide storage tank by utilizing the different electrical conductivity of the material. It is fast, accurate, safe and reliable.

[0014] 3. Sampling ports A and B are set after the microchannel reactor and the multiphase reactor. By sampling and testing the reaction products, the material mixing and reaction conditions can be obtained, which is convenient for adjusting various parameters;

[0015] 4. The present invention realizes the continuous synthesis of dimethyl sulfoxide by connecting a microchannel reactor and a multiphase reactor in series, simplifies the production process, improves the utilization rate of the raw material dimethyl sulfide, reduces the production cost, and has higher yield and production efficiency;

[0016] 5. Continuous feeding and discharging are realized, and production can be started or interrupted as required, which realizes the continuous control of the production process and improves production capacity; BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the continuous synthesis process of dimethyl sulfoxide.

[0018] Description of the symbols in the figure

[0019] 1 Hydrogen peroxide storage tank, 2 mass flow meter A, 3 delivery pump A, 4 microchannel reactor, 5 dimethyl sulfide storage tank, 6 mass flow meter B, 7 delivery pump B, 8 flow automatic control valve A, 9 flow automatic control valve B, 10 thermometer A, 11 pressure gauge A, 12 hot and cold integrated machine A, 13 sampling port A, 14 multiphase reactor, 15 thermometer B, 16 pressure gauge B, 17 hot and cold integrated machine B, 18 sampling port B, 19 liquid level meter, 20 phase separator, 21 solenoid valve, 22 dimethyl sulfoxide storage tank, 23 water phase storage tank. DETAILED DESCRIPTION

[0020] The present invention will be further described below through the following embodiments in conjunction with the accompanying drawings.

[0021] See also Figure 1A continuous production process of dimethyl sulfoxide includes a hydrogen peroxide storage tank 1, a mass flow meter A2, a delivery pump A3, a microchannel reactor 4, a dimethyl sulfide storage tank 5, a mass flow meter B6, a delivery pump B7, a flow automatic control valve A8, a flow automatic control valve B9, a thermometer A10, a pressure gauge A11, a cold and hot integrated machine A12, a sampling port A13, a multiphase reactor 14, a thermometer B15, a pressure gauge B16, a cold and hot integrated machine B17, a sampling port B18, a liquid level meter 19, a phase separator 20, a solenoid valve 21, a dimethyl sulfoxide storage tank 22, and an aqueous phase storage tank 23. The hydrogen peroxide storage tank 1 is divided into three branches through a mass flow meter A2 and a delivery pump A3, which are respectively connected to the microchannel reactor 4. A flow automatic control valve A8 and a flow automatic control valve B9 are respectively arranged after the branch nodes. The dimethyl sulfide storage tank 5 is connected to the microchannel reactor 4 through a mass flow meter B6 and a delivery pump B7. The microchannel reactor 4 is provided with a thermometer A10 and a pressure gauge A11 and is connected to the hot and cold integrated machine A12 through an oil outlet pipe and an oil return pipe. The microchannel reactor 4 is connected to the hot and cold integrated machine A12 through an oil outlet pipe and an oil return pipe. The sampling port A is connected to the multiphase reactor 14. The multiphase reactor 14 is provided with a thermometer B15 and a pressure gauge B16 and is connected to the hot and cold integrated machine B17 through an oil outlet pipe and an oil return pipe. The multiphase reactor 14 is connected to a phase separator 20 through a sampling port B18. The phase separator 20 is provided with a liquid level meter 19. The phase separator 20 is divided into two branches. One branch of the phase separator is connected to a dimethyl sulfoxide storage tank 22 through a solenoid valve 21, and the other branch of the phase separator is connected to a water phase storage tank 23.

[0022] The specific working process of the present invention is as follows:

[0023] The hydrogen peroxide with a mass fraction of 20%-40% in the hydrogen peroxide storage tank 1 is divided into three branches and enters the microchannel reactor 4 through the mass flow meter A2 at a flow rate of 40-90ml / min through the delivery pump A3. The flow rate of the hydrogen peroxide entering the three branches is controlled by the flow automatic control valve A8 and the flow automatic control valve B9. The dimethyl sulfide in the dimethyl sulfide storage tank 5 is passed through the mass flow meter B6 at a flow rate of 30-70ml / min through the delivery pump B7 to enter the microchannel reactor 4 and fully contact and mix with the hydrogen peroxide. The heat required for the reaction is realized by the hot and cold integrated machine A12, and the temperature is controlled at 30-1 00℃, the temperature and pressure of the microchannel reactor are measured by thermometer A10 and pressure gauge A11 respectively, the reaction product enters the multiphase reactor 14 through the sampling port A13 for delayed reaction, the reaction temperature is controlled by the hot and cold integrated machine B17, the reaction temperature and pressure are monitored by thermometer B15 and pressure gauge B16 respectively, the mixed product of dimethyl sulfoxide and aqueous phase generated by the reaction is separated in the phase separator 20 through the sampling port B18, the liquid level of the mixed product in the phase separator 20 is monitored by the liquid level meter 19, wherein dimethyl sulfoxide flows into the dimethyl sulfoxide storage tank 22 through the solenoid valve 21, and the aqueous phase flows into the aqueous phase storage tank 23.

[0024] Example 1

[0025] Hydrogen peroxide with a mass fraction of 40% and dimethyl sulfide were introduced into a microchannel reactor at a molar ratio of 1:1.5. Among them, the hydrogen peroxide was introduced into the 1st, 2nd, and 3rd microchannel reactor plates, which were 50%, 30%, and 20% of the total hydrogen peroxide flow rate respectively. The residence time of the material in the microchannel reactor was controlled to be 20 s. Samples were taken from the sampling port behind the multiphase reactor for gas chromatography analysis, and the selectivity of dimethyl sulfoxide was 99.5%.

[0026] Example 2

[0027] Hydrogen peroxide with a mass fraction of 30% and dimethyl sulfide were introduced into a microchannel reactor at a molar ratio of 1:1.5. Among them, the hydrogen peroxide was introduced into the 1st, 2nd, and 3rd microchannel reactor plates, which were 50%, 30%, and 20% of the total hydrogen peroxide flow rate respectively. The residence time of the material in the microchannel reactor was controlled to be 20 s. Samples were taken from the sampling port behind the multiphase reactor for gas chromatography analysis, and the selectivity of dimethyl sulfoxide was 99.7%.

[0028] Example 3

[0029] Hydrogen peroxide with a mass fraction of 30% and dimethyl sulfide were introduced into a microchannel reactor at a molar ratio of 1:1.5. Among them, the hydrogen peroxide was introduced into the 1st, 2nd, and 3rd microchannel reactor plates, which were 50%, 30%, and 20% of the total hydrogen peroxide flow rate respectively. The residence time of the material in the microchannel reactor was controlled to be 30 s. Samples were taken from the sampling port behind the multiphase reactor for gas chromatography analysis, and the selectivity of dimethyl sulfoxide was 99.9%.

[0030] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Any modification or partial replacement without departing from the spirit of the present invention shall be covered within the scope of the claims of the present invention.

Claims

1. A continuous production process of dimethyl sulfoxide, comprising a hydrogen peroxide storage tank 1, a mass flow meter A2, a delivery pump A3, a microchannel reactor 4, a dimethyl sulfide storage tank 5, a mass flow meter B6, a delivery pump B7, a flow automatic control valve A8, a flow automatic control valve B9, a thermometer A10, a pressure gauge A11, a cold and hot integrated machine A12, a sampling port A13, a multiphase reactor 14, a thermometer B15, a pressure gauge B16, a cold and hot integrated machine B17, a sampling port B18, a liquid level meter 19, a phase separator 20, a solenoid valve 21, a dimethyl sulfoxide storage tank 22, and a water phase storage tank 23. The hydrogen peroxide storage tank 1 is divided into three branches through the mass flow meter A2 and the delivery pump A3, which are respectively connected to the microchannel reactor 4. The flow automatic control valve A8 and the flow automatic control valve A9 are respectively arranged after the branch node. B9, the above-mentioned dimethyl sulfide storage tank 5 is connected to the microchannel reactor 4 through the mass flow meter B6 and the delivery pump B7. The above-mentioned microchannel reactor 4 is provided with a thermometer A10 and a pressure gauge A11 and is connected to the cold and hot integrated machine A12 through an oil outlet pipe and an oil return pipe. The above-mentioned microchannel reactor 4 is connected to the multiphase reactor 14 through the sampling port A. The above-mentioned multiphase reactor 14 is provided with a thermometer B15 and a pressure gauge B16 and is connected to the cold and hot integrated machine B17 through an oil outlet pipe and an oil return pipe. The above-mentioned multiphase reactor 14 is connected to the phase separator 20 through the sampling port B18. The above-mentioned phase separator 20 is provided with a liquid level meter 19. The above-mentioned phase separator 20 is divided into two branches. One branch of the above-mentioned phase separator is connected to the dimethyl sulfoxide storage tank 22 through the solenoid valve 21, and the other branch of the above-mentioned phase separator is connected to the water phase storage tank 23.

2. A continuous production process of dimethyl sulfoxide according to claim 1, characterized in that: The microchannel reactor 4 is composed of six plates connected in series. The three branches connecting the hydrogen peroxide storage tank 1 and the microchannel reactor 4 enter the 1st, 3rd and 5th plates respectively. The flow rate of hydrogen peroxide is controlled by the flow automatic control valve A8 and the flow automatic control valve B9. The 1st plate enters 40%-60% of the total flow rate, the 3rd plate enters 20%-40% of the total flow rate, and the 5th plate enters 0-20% of the total flow rate.

3. A continuous production process of dimethyl sulfoxide according to claim 1, characterized in that: The molar ratio of the reaction materials (hydrogen peroxide: dimethyl sulfide) is 1:1.05-1:5, preferably 1:1-1:2; the reaction temperature is 30-100°C, preferably 40-70°C; the residence time is 0.5-30min, preferably 1-20min.

4. A continuous production process of dimethyl sulfoxide according to claim 1, characterized in that: The multiphase reactor 14 is a "double heat exchange" structure. The heat exchange fluid is passed into the hollow of the stirring shaft, and the heat exchange of the reaction is achieved together with the jacket, which can improve the heat exchange efficiency, avoid the danger caused by local excessive temperature, and improve the safety of production.

5. A continuous production process of dimethyl sulfoxide according to claim 1, characterized in that: The reaction chamber tube length of the multiphase reactor 14 is much larger than the tube diameter, the aspect ratio is about 5-20, the radial thickness of the reaction material is 10mm-300mm, and baffles and closely arranged stirring paddles are arranged in the reaction chamber, which enhances the mass transfer and heat transfer effect of the material and improves the product quality.

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