CN116199603A - Method for synthesizing N, N-diethyl-4-aminobenzenesulfonic acid by adopting continuous flow - Google Patents

Abstract

The invention belongs to the technical field of synthesis of fine chemical raw materials, and in particular relates to a method for synthesizing N,N-diethyl-4-aminobenzenesulfonic acid by continuous flow. Using sulfur trioxide and N,N-diethylaniline as raw materials, using a microchannel continuous flow reaction device, adopting a three-strand circulating feeding method to react in the microchannel reactor, controlling the circulation ratio of the outflowing materials, so that the circulating materials continue to mix with the The raw materials are reacted to obtain N,N-diethyl-4-aminobenzenesulfonic acid with high purity and high yield; wherein, the three feeds are high-concentration N,N-diethylaniline solution and low-concentration trioxide Sulfur solution, and the other is the reaction liquid after the reaction in the reactor is returned for feeding. The invention has mild reaction conditions, high product yield, cost saving and safe production.

Description

A kind of method adopting continuous flow to synthesize N,N-diethyl-4-aminobenzenesulfonic acid

technical field

The invention belongs to the technical field of synthesis of fine chemical raw materials, and in particular relates to a method for synthesizing N,N-diethyl-4-aminobenzenesulfonic acid by continuous flow.

Background technique

N,N-diethyl-4-aminobenzenesulfonic acid is an important medicine and dye intermediate. Generally, N,N-diethylaniline is used as raw material, and it is prepared by electrophilic substitution-aromatic sulfonation reaction under the action of sulfonating agent. As an important intermediate, downstream derivative products such as N,N-diethyl-4-aminobenzenesulfonyl chloride and N,N-dichloroethyl-4-aminobenzenesulfonyl chloride can be produced for subsequent product synthesis. N,N-diethyl-4-aminobenzenesulfonic acid can also be used as a raw material to prepare a series of medicaments, as shown below.

The current literature and patents report that the sulfonating agents for the synthesis of N,N-diethyl-4-aminobenzenesulfonic acid are chlorosulfonic acid and methyl silyl sulfate. Patent WO2012168458 reports that dimethyl silyl sulfate and N,N-diethylaniline were reacted at 170° C. for 4 hours, and the yield was 55%. Patent CN101730680 reports that N,N-dimethylaniline is added to low-temperature chlorosulfonic acid, then reacted at 120°C for 3 hours, and the reaction solution is added to ice water and extracted with dichloromethane, with a yield of only 13%. Chlorosulfonic acid and methyl silyl sulfate are expensive as sulfonating agents, and the yield is not high. The remaining sulfonating agents, such as fuming sulfuric acid and concentrated sulfuric acid, will generate water during the reaction, reduce the reaction concentration and prolong the reaction time, and the sulfuric acid is usually in excess of many times, the economy is not high, and under acidic conditions, N,N -Diethylaniline will remove the ethyl group, generate N-ethylaniline, and then generate N-ethyl-4-aminobenzenesulfonic acid, which needs to be separated after post-treatment, and the yield will be lost. Sulfur trioxide sulfonation method, sulfur trioxide reacts directly with raw materials, no waste acid, fast reaction speed, and can react at an equivalent molar ratio. However, the sulfonation of sulfur trioxide has the problems of poor positioning effect, easy over-sulfonation to produce by-product sulfone, and large heat of reaction. The problem of the inability to remove the heat of reaction in batch-type operation further leads to the occurrence of over-sulfonation. Therefore, how to transfer Dissipating heat is the primary consideration for safe production.

Contents of the invention

In view of the above and the shortcomings of the synthesis of N,N-diethyl-4-aminobenzenesulfonic acid in the prior art, the present invention proposes a method for synthesizing N,N-diethyl-4-aminobenzenesulfonic acid by continuous flow.

In order to achieve the above object, the technical solution adopted by the present invention is:

A method for synthesizing N,N-diethyl-4-aminobenzenesulfonic acid, using sulfur trioxide and N,N-diethylaniline as raw materials, using a microchannel continuous flow reaction device, using three circulating feeds The method is to react in a microchannel reactor, control the circulation ratio of the effluent material, and make the circulating material continue to react with the raw material, thereby obtaining N,N-diethyl-4-aminobenzenesulfonic acid with high purity and high yield; among them, The three feeds are high-concentration N,N-diethylaniline solution and low-concentration sulfur trioxide solution, and the other feed is the reaction liquid after the reaction in the reactor is returned for feeding.

The microchannel continuous flow reaction device comprises a microreactor, a time-delay pipeline reactor, a storage tank and a back pressure valve connected successively by pipelines; a diverter three-way valve is arranged on the pipeline between the time-delay pipeline reactor and the storage tank, The circulating material and the effluent material form a circulation path through the diverting three-way valve.

The reactor is connected by a dispersing channel and a continuous phase reaction channel in a cross; one end of the continuous phase reaction channel is a circulating liquid inlet (103) connected to the storage tank through a pipeline, and the other end is used as a reactor outlet (104) through a pipeline to extend When the pipe reactor is connected; the two ends of the dispersion channel are the feed channels (105, 106) provided by the high-concentration N,N-diethylaniline solution and the low-concentration sulfur trioxide solution respectively, and the two feed channels are respectively connected to the dispersed phase. Inlet lines (101, 102).

A delay pipeline reactor is connected to the outlet of the microchannel reactor, and the reaction liquid enters the delay pipeline reactor to continue the reaction after the reaction in the microreactor is completed. The inner diameter of the delay tube is 2mm, and the wall thickness is 1mm. The temperature of the delay system is controlled by an integrated machine, which is the same as the temperature of the reaction zone.

A back pressure valve is added at the end of the reaction system to maintain a pressure of 0.1-0.4MPa, preferably 0.2-0.3MPa, to avoid solvent volatilization and SO _escape .

The microreactor has a jacket, the jacket is tightly connected to the outside of the continuous phase reaction channel, and the inlet and outlet of the heat exchange fluid are respectively located on the opposite side of the outlet and the inlet of the continuous phase reaction channel, forming a countercurrent exchange with the continuous phase reaction channel. heat mode.

Further,

Since sulfur trioxide reacts quickly and releases a large amount of heat, a microreactor with a jacket is used, that is, the heat exchange channel of the continuous sulfonation microreactor, and the external jacket cooling water is used to cool off the reaction gas quickly. Heat to control the occurrence of side reactions. The heat exchange channel is closely connected to the outside of the reaction channel, and the inlet and outlet of the heat exchange fluid are respectively located on the opposite side of the outlet and inlet of the reaction microchannel, forming a countercurrent heat exchange mode with the reaction channel. Cooling water enters the reactor from the cooling water inlet, and flows out from the cooling water outlet, which automatically adjusts the reaction temperature inside the microchannel reactor. The heat released by the reaction is taken away by the cooling water. The temperature of the reaction module is controlled to be 30-90°C, preferably 50-70°C.

Specifically:

(1) The raw material liquid phase sulfur trioxide solution and N,N-diethylaniline solution are respectively quantitatively and stably passed through two dispersed phase inlet pipelines (101, 102) by the first advection feed pump and the second advection feed pump ) Feed in the microreactor, react in the continuous phase reaction channel of the microreactor;

(2) During the reaction process, the reaction temperature is controlled by the jacket of the microreactor to exchange heat, and the reaction temperature is controlled at 30-90°C;

(3) The reaction product liquid flows out from the reactor outlet (104) and enters the delay pipeline reactor (105) sequentially through the pipeline, and then passes through the split three-way valve to control the reaction product liquid circulation ratio so that it circulates to the reactor and the raw material The reaction is carried out, and the circulating reaction product liquid enters the storage tank, and then returns to the microreactor through the pipeline through the circulating liquid inlet (103) of the microreactor, and is mixed with the raw material, so that the raw material completely generates N,N-diethyl- 4-aminobenzenesulfonic acid product.

The sulfur trioxide solution and the N,N-diethylaniline solution are respectively sulfur trioxide and N,N-diethylaniline diluted with a solvent, and the dilution solvents can be the same or different from 1,2-diethylaniline Ethyl chloride, tetrachloroethane or nitromethane.

On the one hand, the diluent can absorb part of the exothermic heat, and on the other hand, choosing a polar solvent can promote the complexation of the solvent and sulfur trioxide, reduce the activity of sulfur trioxide, and further avoid the occurrence of side reactions. Both N,N-diethylaniline and sulfur trioxide were diluted with diluent.

The concentration of SO in the sulfur trioxide solution is ₃ %-15%; preferably 5%-7.5%; the concentration of N,N-diethylaniline in the N,N-diethylaniline solution is 30-70%, Preferably it is 40-50%; the total molar ratio of N,N-diethylaniline and sulfur trioxide in the system is 1:(1-1.1), preferably 1:(1.03-1.05).

The N,N-diethylaniline feed flow rate is 3-20mL/min, the sulfur trioxide solution flow rate is 3-15mL/min; the circulation ratio is 2-15:1, the small circulation ratio is conducive to improving the conversion efficiency, and the circulation A larger ratio is conducive to improving selectivity, depending on the reaction situation. The split circulation unit is divided by a three-way, and the circulation ratio is controlled by a flow controller.

Beneficial effects of the present invention:

The present invention adopts the method for synthesizing N,N-diethyl-4-aminobenzenesulfonic acid by circulating feed in a microchannel reactor. On the one hand, the microchannel reactor can solve the problem of heat transfer due to good mass transfer, which is conducive to realizing safe production , and increase the yield and shorten the reaction residence time; on the other hand, the way of circulating feed of the reaction liquid is adopted. The material continues to react with the raw material to avoid the generation of persulfonated compounds and improve the reaction yield, specifically:

1. The continuous production of sulfonate has mild reaction conditions, avoids side reactions, and increases yield. Moreover, the mass and heat transfer of the microchannel reactor is efficient, which is convenient for heat transfer and makes the reaction safe and efficient.

2. The method of circular feeding avoids the over-sulfonation of sulfur trioxide to produce by-products such as polysulfonates and sulfones, improves reaction efficiency, saves costs, and achieves intrinsic safety.

3. Circular feeding reduces raw material consumption, avoids raw material loss, and makes recycling difficult.

4. Solvent-liquid phase sulfur trioxide is used to avoid gas phase reaction and no tail gas.

5. The post-processing is simple, the three wastes are less, no waste acid is produced, the safety is high, and the economic benefit is good. It is a green and environmentally friendly process suitable for industrial production.

Description of drawings

Fig. 1 is a schematic diagram of the sulfonation reaction technological process of the present invention,

Fig. 2 is the microreactor structure schematic diagram among Fig. 1,

Fig. 3 is the cross-sectional view of microreactor dispersion channel among Fig. 2,

Wherein, 1 is a microreactor, two dispersed phase inlet pipelines (101,102), continuous phase inlet pipeline (103), reactor outlet pipeline (104) and two dispersed channels (105,106), 2 3 is the first constant flow pump, 3 is the second constant flow pump, 4 is the third constant flow pump, 5 is the delay reactor, 6 is the split three-way valve, 7 is the back pressure valve, and 8 is the storage tank.

Detailed ways

The technical solutions of the present invention are further described below in conjunction with the examples, but the protection scope of the present invention is not limited thereto.

The reaction speed of the sulfur trioxide sulfonation method is fast, and oversulfonation easily occurs to generate by-products such as polysulfonates and sulfones. The present invention adopts a microchannel continuous flow reactor circulation feeding scheme to avoid oversulfonation of sulfur trioxide. The high-concentration N,N-diethylaniline and low-concentration sulfur trioxide solutions pass through the micro-mixer at the same time and then enter the micro-channel reactor. The sulfur trioxide strands are mixed and reacted until all the sulfur trioxide strands are consumed, and finally N,N-diethyl-4-aminobenzenesulfonic acid product is obtained.

The heat exchange problem is realized through the microchannel reactor, the temperature is precisely controlled, and the heat is removed in time. On the other hand, cyclic feeding can avoid the occurrence of side reactions, save the amount of raw materials, and improve the reaction efficiency.

Preparation of sulfur trioxide solution: Add anhydrous dichloroethane into a round bottom flask, add 20mL of fuming sulfuric acid and 25g of phosphorus pentoxide and heat together to 110°C, and receive the dichloroethane solution of sulfur trioxide in a single-mouthed flask at the end . Then add anhydrous dichloroethane to the required concentration, use phenolphthalein as indicator, and NaOH titrate the accurate concentration of the substance.

Liquid chromatography analysis conditions:

Example 1

As shown in Figure 1-3, described microchannel continuous flow reaction device comprises the microreactor, time-delay pipeline reactor, storage tank and back pressure valve that are connected successively by pipeline; Time-delay pipeline reactor and storage tank A diverter three-way valve is set on the pipeline, and the circulating material and the outflow material form a circulation path through the diverter three-way valve.

The reactor is connected by a dispersing channel and a continuous phase reaction channel in a cross; one end of the continuous phase reaction channel is a circulating liquid inlet (103) connected to the storage tank through a pipeline, and the other end is used as a reactor outlet (104) through a pipeline to extend When the pipe reactor is connected; the two ends of the dispersion channel are the feed channels (105, 106) provided by the high-concentration N,N-diethylaniline solution and the low-concentration sulfur trioxide solution respectively, and the two feed channels are respectively connected to the dispersed phase. Inlet lines (101, 102).

A feeding pump is arranged on each of the above-mentioned inlet pipelines.

The microreactor has a jacket, the jacket is tightly connected to the outside of the continuous phase reaction channel, and the inlet and outlet of the heat exchange fluid are respectively located on the opposite side of the outlet and the inlet of the continuous phase reaction channel, forming a countercurrent exchange with the continuous phase reaction channel. heat mode. Cooling water enters the reactor from the cooling water inlet, and flows out from the cooling water outlet, which automatically adjusts the reaction temperature inside the microchannel reactor. The heat released by the reaction is taken away by the cooling water.

Example 2

The ethylene dichloride solution containing 5wt.% _SO and the ethylene dichloride solution containing 40wt.% N,N-diethylaniline were respectively fed by the first advection feed pump and the second advection feed pump Stable feed to the microreactor (the molar ratio of N,N-diethylaniline to SO ₃ is 1:1.05), the flow rate is 6.5mL/min (SO ₃ ) and 8mL/min (N,N- Diethylaniline). Adjust the pressure of the back pressure valve to 0.2MPa, and control the reaction temperature at 50°C with a circulating integrated machine, and obtain a mixed solution of N,N-diethylaniline and N,N-diethyl-4-aminobenzenesulfonic acid at the reaction outlet, That is, the reaction product liquid; after the reaction product liquid is distilled, it passes through the split three-way valve, and the reaction product liquid is divided into the circulating material and the outflow material according to a certain circulation ratio. The circulating material is received in the storage tank, and is returned to the microreactor by the circulating liquid inlet (103) of the microreactor through the third advection pump provided by the pipeline, and simultaneously mixed with sulfur trioxide stock, fresh N,N-diethyl The aniline strand is pumped into the microreactor with a circulation ratio of 4.5:1. After the sulfur trioxide is completely consumed, the feeding is stopped, and the circulating liquid continues to circulate until the N,N-diethylaniline <1% is detected by the liquid chromatography, and the circulation stops. According to liquid chromatography analysis of the reaction liquid, the yield of the final product N,N-diethyl-4-aminobenzenesulfonic acid reaches 91%, and the purity is greater than 99%.

Example 3

The dichloroethane solution containing 5wt.% _SO3 and the dichloroethane solution containing 50wt.% N,N-diethylaniline are respectively fed by the first advection feed pump and the second advection feed pump Stable feed to the microreactor (the molar ratio of N,N-diethylaniline to SO ₃ is 1:1.05), the flow rate is 6mL/min (SO ₃ ) and 6mL/min (N,N-diethylaniline ethylaniline). Adjust the pressure of the back pressure valve to 0.2MPa, and control the reaction temperature at 50°C with a circulating integrated machine, and obtain a mixed solution of N,N-diethylaniline and N,N-diethyl-4-aminobenzenesulfonic acid at the reaction outlet, That is, the reaction product liquid; after the reaction product liquid is distilled, it passes through the split three-way valve, and the reaction product liquid is divided into the circulating material and the outflow material according to a certain circulation ratio. The circulating material is received in the storage tank, and the circulating liquid inlet (103) of the microreactor is returned to the microreactor through the third advection pump provided by the pipeline, and simultaneously mixed with sulfur trioxide stock, fresh N,N-diethyl The aniline strand is pumped into the microreactor with a circulation ratio of 6:1. After the sulfur trioxide is completely consumed, the feeding is stopped, and the circulating liquid continues to circulate until the N,N-diethylaniline <1% is detected by the liquid chromatography, and the circulation stops. According to liquid chromatography analysis of the reaction solution, the yield of the final product N,N-diethyl-4-aminobenzenesulfonic acid reaches 95%, and the purity is greater than 99%.

Example 4

The ethylene dichloride solution containing 5wt.% _SO and the ethylene dichloride solution containing 40wt.% N,N-diethylaniline were respectively fed by the first advection feed pump and the second advection feed pump Stable feed to the microreactor (the molar ratio of N,N-diethylaniline to SO ₃ is 1:1.10), the flow rate is 6.5mL/min (SO ₃ ) and 8mL/min (N,N- Diethylaniline). Adjust the pressure of the back pressure valve to 0.2MPa, and control the reaction temperature at 50°C with a circulating integrated machine, and obtain a mixed solution of N,N-diethylaniline and N,N-diethyl-4-aminobenzenesulfonic acid at the reaction outlet, That is, the reaction product liquid; after the reaction product liquid is distilled, it passes through the split three-way valve, and the reaction product liquid is divided into the circulating material and the outflow material according to a certain circulation ratio. The circulating material is received in the storage tank, and the circulating liquid inlet (103) of the microreactor is returned to the microreactor through the third advection pump provided by the pipeline, and simultaneously mixed with sulfur trioxide stock, fresh N,N-diethyl The aniline strand is pumped into the microreactor with a circulation ratio of 4.5:1. After the sulfur trioxide is completely consumed, the feeding is stopped, and the circulating liquid continues to circulate until the N,N-diethylaniline <1% is detected by the liquid chromatography, and the circulation stops. According to liquid chromatography analysis of the reaction solution, the yield of the final product N,N-diethyl-4-aminobenzenesulfonic acid reaches 92%, and the purity is greater than 98%.

Example 5

The ethylene dichloride solution containing 5wt.% _SO and the ethylene dichloride solution containing 40wt.% N,N-diethylaniline were respectively fed by the first advection feed pump and the second advection feed pump Stable feed to the microreactor (the molar ratio of N,N-diethylaniline to SO ₃ is 1:1.05), the flow rate is 6.5mL/min (SO ₃ ) and 8mL/min (N,N- Diethylaniline). Adjust the pressure of the back pressure valve to 0.3MPa, and control the reaction temperature at 50°C with a circulating integrated machine, and obtain a mixed solution of N,N-diethylaniline and N,N-diethyl-4-aminobenzenesulfonic acid at the reaction outlet, That is, the reaction product liquid; after the reaction product liquid is distilled, it passes through the split three-way valve, and the reaction product liquid is divided into the circulating material and the outflow material according to a certain circulation ratio. The circulating material is received in the storage tank, and the circulating liquid inlet (103) of the microreactor is returned to the microreactor through the third advection pump provided by the pipeline, and simultaneously mixed with sulfur trioxide stock, fresh N,N-diethyl The aniline strand is pumped into the microreactor with a circulation ratio of 4.5:1. After the sulfur trioxide is completely consumed, the feeding is stopped, and the circulating liquid continues to circulate until the N,N-diethylaniline <1% is detected by the liquid chromatography, and the circulation stops. According to liquid chromatography analysis of the reaction liquid, the yield of the final product N,N-diethyl-4-aminobenzenesulfonic acid reaches 82%, and the purity is greater than 99%.

Example 6

The ethylene dichloride solution containing 5wt.% _SO and the ethylene dichloride solution containing 40wt.% N,N-diethylaniline were respectively fed by the first advection feed pump and the second advection feed pump Stable feed to the microreactor (the molar ratio of N,N-diethylaniline to SO ₃ is 1:1.05), the flow rate is 9.6mL/min (SO ₃ ) and 12mL/min (N,N- Diethylaniline). Adjust the pressure of the back pressure valve to 0.25MPa, and control the reaction temperature at 50°C with the integrated circulation machine, and obtain a mixed solution of N,N-diethylaniline and N,N-diethyl-4-aminobenzenesulfonic acid at the reaction outlet, That is, the reaction product liquid; after the reaction product liquid is distilled, it passes through the split three-way valve, and the reaction product liquid is divided into the circulating material and the outflow material according to a certain circulation ratio. The circulating material is received in the storage tank, and is returned to the microreactor by the circulating liquid inlet (103) of the microreactor through the third advection pump provided by the pipeline, and simultaneously mixed with sulfur trioxide stock, fresh N,N-diethyl The aniline strand is pumped into the microreactor with a circulation ratio of 5.4:1. After the sulfur trioxide is completely consumed, the feeding is stopped, and the circulating liquid continues to circulate until the N,N-diethylaniline <1% is detected by the liquid chromatography, and the circulation stops. According to liquid chromatography analysis of the reaction liquid, the yield of the final product N,N-diethyl-4-aminobenzenesulfonic acid reaches 88%, and the purity is greater than 99%.

Comparative example 1

The ethylene dichloride solution containing 5wt.% _SO and the ethylene dichloride solution containing 40wt.% N,N-diethylaniline were respectively fed by the first advection feed pump and the second advection feed pump Stable feeding (wherein, N, N-diethylaniline and SO _mol ratio is 1:1.05) to microreactor, adjust the flow of reactant N, N-diethylaniline and sulfur trioxide solution, make The molar ratio of N,N-diethylaniline to sulfur trioxide is 1:1.05. Adjust the pressure of the back pressure valve to 0.2MPa, and control the reaction temperature at 50°C with a circulating integrated machine, and obtain a mixed solution of N,N-diethylaniline and N,N-diethyl-4-aminobenzenesulfonic acid at the reaction outlet, That is, the reaction product liquid, the liquid chromatographic analysis of the reaction liquid, the yield of the final product N,N-diethyl-4-aminobenzenesulfonic acid reaches 76%, and the purity is greater than 98%.

Comparative example 2

After mixing 49.2 g of N,N-diethylaniline and 254 g of o-dichlorobenzene, slowly add 34.9 g of concentrated sulfuric acid under stirring, and there is an exothermic phenomenon. Turn on the electric heating mantle and the transformer to heat the reaction device and the water separator respectively. The temperature of the reaction liquid is 180°C, and the time is counted after the water is distilled off. Stop heating when the water level no longer rises, and the reaction time is 6-8h. The yield of the final product N,N-diethyl-4-aminobenzenesulfonic acid reaches 67%, and the purity is greater than 97%.

Claims (8)

1. A method for synthesizing N, N-diethyl-4-aminobenzenesulfonic acid, which is characterized by comprising the following steps: sulfur trioxide and N, N-diethyl aniline are used as raw materials, a micro-channel continuous flow reaction device is utilized, a three-strand circulating feeding mode is adopted to react in a micro-channel reactor, the circulating ratio of effluent materials is controlled, circulating materials continue to react with the raw materials, and then the N, N-diethyl-4-aminobenzenesulfonic acid is obtained with high purity and high yield; wherein three feeds are high-concentration N, N-diethylaniline solution and low-concentration sulfur trioxide solution, and the other feed is the reaction solution after the reaction of the reactor, and the reaction solution is returned for feeding.

2. A method of synthesizing N, N-diethyl-4-aminobenzenesulfonic acid according to claim 1, characterized in that: the micro-channel continuous flow reaction device comprises a micro-reactor, a delay pipeline reactor, a storage tank and a back pressure valve which are sequentially connected through pipelines; and a flow dividing three-way valve is arranged on a pipeline between the delay pipeline reactor and the storage tank, and the circulating material and the outflow material form a circulating path through the flow dividing three-way valve.

3. A method of synthesizing N, N-diethyl-4-aminobenzenesulfonic acid according to claim 2, characterized in that: the reactor is formed by connecting a dispersing channel and a continuous phase reaction channel in a cross shape; one end of the continuous phase reaction channel is a circulating liquid inlet (103) which is connected with the storage tank through a pipeline, and the other end of the continuous phase reaction channel is used as a reactor outlet (104) which is connected with the delay pipeline reactor through a pipeline; the two ends of the dispersion channel are respectively provided with feed channels (105, 106) for raw materials of high-concentration N, N-diethylaniline solution and low-concentration sulfur trioxide solution, and the two feed channels are respectively connected with a disperse phase inlet pipeline (101, 102).

4. A process for the synthesis of N, N-diethyl-4-aminobenzenesulfonic acid according to claim 3, characterized in that: the microreactor is provided with a jacket, the jacket is tightly connected with the outside of the continuous phase reaction channel, and a heat exchange fluid inlet and a heat exchange fluid outlet are respectively positioned at the opposite sides of the outlet and the inlet of the continuous phase reaction channel and form a countercurrent heat exchange mode with the continuous phase reaction channel.

5. A process for the synthesis of N, N-diethyl-4-aminobenzenesulfonic acid according to any one of claims 1 to 4, characterized in that:

(1) The raw material liquid-phase sulfur trioxide solution and the N, N-diethyl aniline solution are quantitatively and stably fed into the micro-reactor respectively through two disperse phase inlet pipelines (101, 102) by a first advection feed pump and a second advection feed pump respectively, and react in a continuous phase reaction channel of the micro-reactor;

(2) In the reaction process, the reaction temperature is controlled by a jacket of the micro-reactor, heat exchange is carried out, and the reaction temperature is controlled to be 30-90 ℃;

(3) The reaction generating liquid flows out from the outlet (104) of the reactor and sequentially enters the delay pipeline reactor (105) through a pipeline, then the circulation ratio of the reaction generating liquid is controlled through a split-flow three-way valve, the reaction generating liquid is circulated to the reactor to react with raw materials, the circulated reaction generating liquid enters a storage tank, and then the circulated reaction generating liquid returns to the microreactor through the circulating liquid inlet (103) of the microreactor through the pipeline and is mixed with the raw materials, so that the raw materials completely generate N, N-diethyl-4-aminobenzenesulfonic acid products.

6. The method for synthesizing N, N-diethyl-4-aminobenzenesulfonic acid according to claim 5, wherein:

the sulfur trioxide solution and the N, N-diethylaniline solution are respectively sulfur trioxide and N, N-diethylaniline which are respectively diluted by solvents, and the solvents for dilution can be the same or different and are selected from 1, 2-dichloroethane, tetrachloroethane or nitromethane.

7. The method for synthesizing N, N-diethyl-4-aminobenzenesulfonic acid according to claim 6, wherein: SO in the sulfur trioxide solution ₃ The concentration is 3% -15%; the concentration of N, N-diethylaniline in the N, N-diethylaniline solution is 30-70%; the total molar ratio of N, N-diethylaniline to sulfur trioxide in the system is 1: (1-1.1).

8. The method for synthesizing N, N-diethyl-4-aminobenzenesulfonic acid according to claim 5, wherein: the feeding flow rate of the N, N-diethyl aniline is 3-20mL/min, and the flow rate of the sulfur trioxide solution is 3-15mL/min; the circulation ratio is 2-15:1.

Images