Preparation method of N-methyl-N-isopropyl amino sulfonamide

Abstract

The invention discloses a preparation method of N-methyl-N-isopropyl amino sulfonamide, belongs to the field of organic synthesis, and particularly relates to a preparation method of N-methyl-N-isopropyl amino sulfonamide. Comprising the following steps: S1, reacting a mixture of N-methylisopropylamine and a solvent with a mixture of sulfonyl chloride and a solvent in a micro-channel continuous flow reactor I, absorbing tail gas by using sodium hydroxide absorption liquid, collecting reaction liquid after the reaction is finished, washing with water, and desolventizing to obtain an intermediate N-methyl-N-isopropyl amino sulfonyl chloride; and S2, simultaneously transporting the N-methyl-N-isopropyl amino sulfonyl chloride obtained in the step S1 and ammonia water into a microchannel continuous flow reactor II for reaction, and then performing post-treatment to obtain a target product. According to the preparation method, reactant separation and purification operation is simpler, the production cost is lower, the reaction efficiency is higher, and industrial large-scale production can be realized.

Description

Technical Field

[0001] The present invention relates to the field of organic synthesis, and more particularly, to a method for preparing N-methyl-N-isopropylsulfonamide. Background Art

[0002] Sulfentrazone is a novel uracil herbicide and also a novel herbicide of the protoporphyrinogen oxidase (PPO) inhibitor class, which is mostly used for various crops (including corn); this herbicide can selectively control dicotyledonous weeds before emergence. Sulfentrazone has great potential as a novel herbicide and can be mixed with other herbicides to achieve better effects. The chemical structural formula of sulfentrazone is shown as follows:

[0003]

[0004] N-Methyl-N-isopropylsulfonamide is an important intermediate for synthesizing sulfentrazone. Currently, the mainstream synthesis methods are divided into two types. The first is: ① using N-methylisopropylamine and sulfonyl chloride as raw materials, reacting under the action of an acid-binding agent to generate the intermediate N-methyl-N-isopropylaminosulfonyl chloride, and then reacting with ammonia or aqueous ammonia to obtain N-methyl-N-isopropylsulfonamide; the second is: ② using N-methylisopropylamine, sulfur trioxide and phosphorus pentachloride as raw materials, generating the intermediate N-methyl-N-isopropylaminosulfonyl chloride under the action of an acid-binding agent, and then reacting with ammonia or aqueous ammonia to obtain N-methyl-N-isopropylsulfonamide. The reaction process is shown as follows:

[0005]

[0006] The acid-binding agent added during the reaction of N-methylisopropylamine and sulfonyl chloride to synthesize N-methyl-N-isopropylaminosulfonyl chloride is usually triethylamine, which is used to neutralize the generated HCl. After the reaction, a strong base such as NaOH needs to be added to recover triethylamine. Generally in industry, the recovery rate of triethylamine is about 80%. If the remaining triethylamine is to be recovered continuously, the economic cost will increase significantly.

[0007] Reacting N-methyl-N-isopropylaminosulfonyl chloride with aqueous ammonia or ammonia can obtain N-methyl-N-isopropylsulfonamide. As described in the US patent with the patent number US7232926B2 authorized on June 19, 2007, after the reaction of N-methyl-N-isopropylaminosulfonyl chloride with aqueous ammonia ends, water needs to be evaporated, and then an organic solvent is added for dissolution, filtration, and concentration under reduced pressure to obtain the product. This method has a relatively high yield, but the energy consumption required for evaporating water is relatively large. There are also literatures using ammonia as the raw material for ammoniation, but this method requires special equipment, an autoclave; and ammonia has certain safety hazards and is prone to corroding pipelines and autoclaves.

[0008] In addition to the above method, other routes for synthesizing N-methyl-N-isopropylsulfamamide are as follows: Using chlorosulfonyl isocyanate as the raw material, first reacting with tert-butanol, and then reacting with N-methylisopropylamine to obtain tert-butyl N-(N-methyl-N-isopropylsulfamoyl)carbamate, and finally performing deprotection of the amino group to obtain N-methyl-N-isopropylsulfamamide; however, the yield of this method is not high, and the price of chlorosulfonyl isocyanate is high, so it is not suitable for industrialization.

[0009] Therefore, it is necessary to provide a method for preparing N-methyl-N-isopropylsulfamamide with high yield, low cost and convenient operation. Summary of the Invention

[0010] Aiming at the problems existing in the prior art, the purpose of the present invention is to provide a method for preparing N-methyl-N-isopropylsulfamamide by continuous flow reaction, which makes the separation and purification operations of the reactants simpler, the production cost lower, the reaction efficiency higher, and can realize large-scale industrial production.

[0011] To solve the above problems, the present invention adopts the following technical solutions.

[0012] A method for preparing N-methyl-N-isopropylsulfamamide, comprising the following steps: S1: The mixture of N-methylisopropylamine and solvent reacts with the mixture of sulfonyl chloride and solvent in a microchannel continuous flow reactor I, and then the tail gas is absorbed by sodium hydroxide absorbent. After the reaction is completed, the reaction solution is collected, washed with water, and the solvent is removed to obtain the intermediate N-methyl-N-isopropylsulfamoyl chloride;

[0013] S2: The N-methyl-N-isopropylsulfamoyl chloride obtained in step S1 and ammonia water are simultaneously transported into a microchannel continuous flow reactor II for reaction, and then post-treatment is carried out to obtain the target product.

[0014] Further, the solvent in step S1 is an aprotic solvent, and the solvent is dichloromethane, dichloroethane, toluene or chloroform.

[0015] Further, the molar ratio of N-methylisopropylamine, sulfonyl chloride and ammonia water is 1:1.0-2.0:2.0-10.0.

[0016] Further, in step S1, the mass ratio of N-methylisopropylamine to the solvent is 1:1.0-4.0.

[0017] Further, in step S1, the mass ratio of sulfonyl chloride to the solvent is 1:1.0-4.0.

[0018] Further, in step S2, the mass concentration of ammonia water is 15-28%.

[0019] Further, the reaction temperature in step S1 is 5 - 20°C, and the reaction residence time is 1 - 10 min.

[0020] Further, the reaction temperature in step S2 is 15 - 55°C, and the reaction residence time is 5 - 15 min.

[0021] Further, the post - treatment method in step S2 is as follows: Cool the reaction solution to 0 - 5°C and stir for 0.5 - 2 h, filter, wash the filter cake with a small amount of ice water, and vacuum - dry at 40 - 50°C for 12 - 36 h to obtain N - methyl - N - isopropylsulfamamide.

[0022] The specific synthesis method is as follows:

[0023] A preparation method of N - methyl - N - isopropylsulfamamide, the preparation method is as follows: Prepare material A with N - methylisopropylamine and a solvent, the mass ratio of N - methylisopropylamine to the solvent is 1:1.0 - 4.0; Prepare material B with sulfonyl chloride and a solvent, the mass ratio of sulfonyl chloride to the solvent is 1:1.0 - 4.0; The solvents of material A and material B are the same, and the solvents are all dichloromethane, dichloroethane, toluene or chloroform; Ammonia water is used as material C, the mass concentration of the ammonia water is 15 - 28%, and the molar ratio of N - methylisopropylamine, sulfonyl chloride and ammonia water is 1:1.0 - 2.0:2.0 - 10.0; Material A and material B enter the micro - channel continuous - flow reactor I through a delivery pump I and a delivery pump II respectively for reaction at the same time, the reaction solution is received in a receiving bottle, and the tail gas is connected to a sodium hydroxide absorption solution. After the reaction solution in the receiving bottle is washed with water and desolvated, the obtained intermediate N - methyl - N - isopropylsulfamoyl chloride is used as material D; The reaction temperature in the micro - channel continuous - flow reactor I is 5 - 20°C, and the reaction residence time in the micro - channel continuous - flow reactor I is 1 - 10 min; The material C delivered by the delivery pump III and the material D delivered by the delivery pump IV enter the micro - channel continuous - flow reactor II for reaction at the same time, and the target product is obtained after post - treatment; The reaction temperature in the micro - channel continuous - flow reactor II is 15 - 55°C, and the reaction residence time in the micro - channel continuous - flow reactor II is 5 - 15 min; The post - treatment method is: Cool the reaction solution to 0 - 5°C, stir for 0.5 - 2 h, filter, wash the filter cake with a small amount of ice water, and vacuum - dry at 40°C - 50°C for 12 - 36 h to obtain the product N - methyl - N - isopropylsulfamamide.

[0024] Compared with the prior art, the advantages of the present invention are as follows:

[0025] First, by continuously transporting raw materials using a delivery pump and reacting in a micro - channel continuous - flow reactor, the present invention realizes the continuous and controllable reaction process, can easily achieve closed - loop, continuous and automated production. In addition, this preparation method also has the advantages of high safety factor, etc.

[0026] Second, in the first-step reaction of N-methylisopropylamine and sulfonyl chloride in the present invention, the use of an acid-binding agent is avoided, thereby also avoiding the recovery process of the acid-binding agent, making the operation more convenient and more economical.

[0027] Third, the post-treatment of the second-step amination reaction of the present invention is simple, does not involve organic solvents, and the product can be precipitated by freezing. Brief Description of the Drawings

[0028] Figure 1 is a process schematic diagram of the present invention;

[0029] Figure 2 is the 1 1H NMR spectrum of N-methyl-N-isopropylsulfamamide;

[0030] Figure 3 is the 13 13C NMR spectrum of N-methyl-N-isopropylsulfamamide. Brief Description of the Drawings:

[0032] 1 Delivery pump I, 2 Delivery pump II, 3 Delivery pump III, 4 Delivery pump IV, 5 Microchannel continuous flow reactor I, 6 Microchannel continuous flow reactor II. Detailed Embodiments

[0033] The present invention will be further described below through specific examples, but the protection scope of the present invention is not limited thereto.

[0034] Example 1:

[0035] 146.2 g of N-methylisopropylamine was configured into a 500 mL mixed solution with dichloromethane as material A, 366.9 g of sulfonyl chloride was configured into a 500 mL mixed solution with dichloromethane as material B, and 408.0 g of ammonia water with a mass concentration of 25% was used as material C. Material A and material B were respectively transported through delivery pump I 1 and delivery pump II 2 through pipelines to microchannel continuous flow reactor I 5, the reaction temperature was controlled at 10 °C by an oil bath, the reaction solution stayed in microchannel continuous flow reactor I 5 for 7 min for reaction, and then the reaction solution was collected using a receiving bottle, and the tail gas was absorbed by a sodium hydroxide absorption solution. Post-treatment one was carried out on the collected reaction solution: the reaction solution collected in the receiving bottle was washed with water three times (300 mL * 3), the three water phases were combined and then back-extracted once with dichloromethane (500 mL), the two organic phases were combined, and the solvent was removed under reduced pressure to obtain 305.1 g of a pale yellow intermediate N-methyl-N-isopropylsulfamoyl chloride liquid (GC purity: 97.0%, yield: 89.2%)

[0036] The obtained N-methyl-N-isopropylsulfamoyl chloride liquid is used as Material D. Material C and Material D are respectively transported to the microchannel continuous flow reactor II 6 through the transfer pump III 3, the transfer pump IV 4 and pipelines. The reaction temperature is controlled at 25 °C by an oil bath, and the reaction is carried out in the microchannel continuous flow reactor II 6 for 10 min. Subsequently, the reaction solution is collected and post-treated as follows: The collected reaction solution is cooled to below 5 °C, stirred for 0.5 h, filtered, and the filter cake is rinsed with a small amount of ice water and vacuum dried at 50 °C for 24 h to obtain 253.9 g of white product N-methyl-N-isopropylsulfamide (total two-step yield: 83.5%, GC purity: 97.0%).

[0037] 1 H NMR (400 MHz, Chloroform-d) δ 4.86 (s, 2H), 4.14 (dt, J = 26.9, 6.7 Hz, 1H), 2.67 (s, 3H), 1.12 (d, J = 6.8 Hz, 6H); 13 C NMR (101 MHz, Chloroform-d) δ 49.2, 27.6, 19.5.

[0038] Example 2:

[0039] 146.2 g of N-methylisopropylamine is configured into a 500 mL mixed solution with dichloromethane as Material A, 318.7 g of sulfonyl chloride is configured into a 500 mL mixed solution with dichloromethane as Material B, and 408.0 g of ammonia water with a mass concentration of 25% is used as Material C. Material A and Material B are respectively transported to the microchannel continuous flow reactor I 5 through the transfer pump I 1, the transfer pump II 2 and pipelines. The reaction temperature is controlled at 10 °C by an oil bath, and the reaction solution reacts in the microchannel continuous flow reactor I 5 for 7 min. Subsequently, the reaction solution is collected using a receiving bottle, and the tail gas is absorbed by a sodium hydroxide absorption solution. The collected reaction solution is post-treated as follows: The reaction solution is washed with water three times (300 mL * 3), the three aqueous phases are combined and then back-extracted once with dichloromethane (500 mL), the two organic phases are combined, and the solvent is removed under reduced pressure to obtain 296.8 g of light yellow intermediate N-methyl-N-isopropylsulfamoyl chloride liquid (GC purity: 97.4%, yield: 86.8%).

[0040] The obtained liquid N-methyl-N-isopropylsulfamoyl chloride is used as Material D. Material C and Material D are respectively transported to the microchannel continuous flow reactor II 6 through the delivery pump III 3, the delivery pump IV 4 and pipelines. The reaction temperature is controlled at 25 °C by an oil bath. The reaction is carried out for 10 min while staying in the microchannel continuous flow reactor II 6. Subsequently, the reaction solution is collected and post-treated as follows: The reaction solution is cooled to below 5 °C, stirred for 1 h, filtered, the filter cake is rinsed with a small amount of ice water, and vacuum dried at 50 °C for 24 h to obtain 250.3 g of white product N-methyl-N-isopropylsulfamide (total yield of two steps: 82.3%, GC purity: 97.1%).

[0041] Example 3:

[0042] 146.2 g of N-methylisopropylamine is configured into a 500 mL mixed solution with dichloromethane as Material A, 416.9 g of sulfonyl chloride is configured into a 500 mL mixed solution with dichloromethane as Material B, and 272.0 g of ammonia water with a mass concentration of 25% is used as Material C. Material A and Material B are respectively transported to the microchannel continuous flow reactor I 5 through the delivery pump I 1 and the delivery pump II 2 via pipelines. The reaction temperature is controlled at 15 °C by an oil bath. The reaction solution stays in the microchannel continuous flow reactor I 5 for 8 min for reaction. Subsequently, the reaction solution is collected using a receiving bottle, and the tail gas is absorbed by a sodium hydroxide absorption solution. The collected reaction solution is post-treated as follows: The reaction solution is washed with water three times (300 mL * 3), the three aqueous phases are combined and then back-extracted once with dichloromethane (500 mL). The two organic phases are combined and stripped under reduced pressure to obtain 307.8 g of light yellow intermediate liquid N-methyl-N-isopropylsulfamoyl chloride (GC purity: 98.2%, yield: 90.0%)

[0043] The obtained liquid N-methyl-N-isopropylsulfamoyl chloride is used as Material D. Material C and Material D are respectively transported to the microchannel continuous flow reactor II 6 through the delivery pump III 3, the delivery pump IV 4 and pipelines. The reaction temperature is controlled at 35 °C by an oil bath. The reaction is carried out for 10 min while staying in the microchannel continuous flow reactor II 6. Subsequently, the reaction solution is collected and post-treated as follows: The collected reaction solution is cooled to below 5 °C, stirred for 1.5 h, filtered, the filter cake is rinsed with a small amount of ice water, and vacuum dried at 50 °C for 24 h to obtain 255.3 g of white product N-methyl-N-isopropylsulfamide (total yield of two steps: 84.0%, GC purity: 96.4%).

[0044] Example 4:

[0045] 146.2 g of N-methylisopropylamine was dissolved in dichloromethane to prepare a 500 mL mixed solution as Material A. 535.0 g of sulfonyl chloride was dissolved in dichloromethane to prepare a 500 mL mixed solution as Material B. 1360.0 g of ammonia water with a mass concentration of 25% was used as Material C. Material A and Material B were respectively transported through pipeline by transfer pump I1 and transfer pump II 2 to microchannel continuous flow reactor I 5. The reaction temperature was controlled at 15 °C by an oil bath. The reaction solution was retained in microchannel continuous flow reactor I 5 for 9 min for reaction. Subsequently, the reaction solution was collected using a receiving flask, and the tail gas was absorbed by sodium hydroxide absorption solution. Post-treatment I was performed on the collected reaction solution: the reaction solution was washed with water three times (300 mL * 3), the three aqueous phases were combined and then back-extracted once with dichloromethane (500 mL). The two organic phases were combined and solvent was removed under reduced pressure to obtain 311.2 g of light yellow intermediate N-methyl-N-isopropylsulfamoyl chloride liquid (GC purity: 97.2%, yield: 91.0%).

[0046] The obtained N-methyl-N-isopropylsulfamoyl chloride liquid was used as Material D. Material C and Material D were respectively transported through pipeline by transfer pump III 3 and transfer pump IV 4 to microchannel continuous flow reactor II 6. The reaction temperature was controlled at 35 °C by an oil bath. The reaction solution was retained in microchannel continuous flow reactor II 6 for 10 min for reaction. The reaction solution was collected and post-treatment II was performed on it: the collected reaction solution was cooled to below 5 °C, stirred for 1.5 h, filtered, the filter cake was rinsed with a small amount of ice water, and dried under vacuum at 50 °C for 24 h to obtain 237.1 g of white product N-methyl-N-isopropylsulfamide (total two-step yield: 78.0%, GC purity: 96.4%).

[0047] Example 5:

[0048] 146.2 g of N-methylisopropylamine was dissolved in dichloromethane to prepare a 500 mL mixed solution as Material A. 535.0 g of sulfonyl chloride was dissolved in dichloromethane to prepare a 500 mL mixed solution as Material B. 272.5 g of ammonia water with a mass concentration of 25% was used as Material C. Material A and Material B were respectively transported through pipeline by transfer pump I1 and transfer pump II 2 to microchannel continuous flow reactor I 5. The reaction temperature was controlled at 15 °C by an oil bath. The reaction solution was retained in microchannel continuous flow reactor I 5 for 10 min for reaction. Subsequently, the reaction solution was collected using a receiving flask, and the tail gas was absorbed by sodium hydroxide absorption solution. Post-treatment I was performed on the collected reaction solution: the reaction solution was washed with water three times (300 mL * 3), the three aqueous phases were combined and then back-extracted once with dichloromethane (500 mL). The two organic phases were combined and solvent was removed under reduced pressure to obtain 318.1 g of light yellow intermediate N-methyl-N-isopropylsulfamoyl chloride liquid (GC purity: 97.7%, yield: 93.0%).

[0049] The obtained liquid N-methyl-N-isopropylsulfamoyl chloride is used as Material D. Material C and Material D are respectively transported to the microchannel continuous flow reactor II 6 through the transfer pump III 3, the transfer pump IV 4 and pipelines. The reaction temperature is controlled at 35 °C by an oil bath. The reaction is carried out for 10 min while staying in the microchannel continuous flow reactor II 6. Subsequently, the reaction solution is collected and post-treated as follows: The collected reaction solution is cooled to below 5 °C, stirred for 1.5 h, filtered, the filter cake is rinsed with a small amount of ice water, and vacuum dried at 50 °C for 24 h to obtain 262.4 g of white product N-methyl-N-isopropylsulfamide (total two-step yield: 86.3%, GC purity: 97.5%).

[0050] Example 6:

[0051] 146.2 g of N-methylisopropylamine is configured into a 500 mL mixed solution with dichloromethane as Material A, 267.8 g of sulfonyl chloride is configured into a 500 mL mixed solution with dichloromethane as Material B, and 544.0 g of ammonia water with a mass concentration of 25% is used as Material C. Material A and Material B are respectively transported to the microchannel continuous flow reactor I 5 through the transfer pump I 1 and the transfer pump II 2 via pipelines. The reaction temperature is controlled at 15 °C by an oil bath. The reaction solution stays in the pipeline for 8 min for reaction. Subsequently, the reaction solution is collected using a receiving bottle, and the tail gas is absorbed by a sodium hydroxide absorption solution. The collected reaction solution is post-treated as follows: The reaction solution is washed with water three times (300 mL * 3), the three water phases are combined and then back-extracted once with dichloromethane (500 mL), the two organic phases are combined, and the solvent is removed under reduced pressure to obtain 280.4 g of light yellow intermediate liquid N-methyl-N-isopropylsulfamoyl chloride (GC purity: 96.2%, yield: 82.0%).

[0052] The obtained liquid N-methyl-N-isopropylsulfamoyl chloride is used as Material D. Material C and Material D are respectively transported to the microchannel continuous flow reactor II 6 through the transfer pump III 3, the transfer pump IV 4 and pipelines. The reaction temperature is controlled at 35 °C by an oil bath. The reaction is carried out for 10 min while staying in the microchannel continuous flow reactor II 6. Subsequently, the reaction solution is collected and post-treated as follows: The collected reaction solution is cooled to below 5 °C, stirred for 1.5 h, filtered, the filter cake is rinsed with a small amount of ice water, and vacuum dried at 50 °C for 24 h to obtain 235.7 g of white product N-methyl-N-isopropylsulfamide (total two-step yield: 77.5%, GC purity: 96.9%).

[0053] Comparative Example 1:

[0054] A solution of 63.2 g (0.41 mol) of 52% sulfur trioxide in 1,2-dichloroethane was added dropwise with stirring within a temperature range of 0 to 5 °C over 15 min to a solution of 70 g (0.752 mol) of α-methylpyridine dissolved in 250 mL of 1,2-dichloroethane. Subsequently, it was washed with 50 mL of 1,2-dichloroethane and stirred for 15 min until the temperature rose to 25 °C. Then, 26.3 g (0.342 mol) of 95% pure N-methyl-N-[1-methylethyl]amine was added dropwise with stirring within a temperature range of 20 to 35 °C over 15 min, followed by washing with 50 mL of 1,2-dichloroethane and stirring at 55 °C for 15 min. After cooling to 20 °C, 42.7 g (0.205 mol) of phosphorus pentachloride was added dropwise with stirring within a temperature range of 20 to 32 °C over 15 min under external cooling conditions, followed by washing with 150 mL of 1,2-dichloroethane. After stirring at 70 °C for 2 h, the reaction mixture was concentrated under reduced pressure and distilled through a Normag column head of a 10 cm column tube to obtain 35 g (59.6% of the theoretical value) of N-methyl-N-isopropylsulfamoyl chloride with a boiling point of 110 - 115 °C / 30 mbar.

[0055] With stirring, at a temperature of 0 - 5 °C, within 5 min, 15 g (0.083 mol) of the obtained N-methyl-N-isopropylsulfamoyl chloride was added to 49 mL (0.654 mol) of 25% aqueous ammonia solution, and then stirred at a temperature of 5 - 10 °C for another 45 min. The reaction mixture was concentrated under reduced pressure, and then the residue was stirred in dichloromethane, the insoluble precipitate was removed, washed, and concentrated again under reduced pressure. 11.3 g of N-methyl-N-isopropylsulfamide with a melting point of 51 - 53 °C, a purity of 95%, and a yield of 84.9% of the theoretical value was obtained.

[0056] It can be seen from Examples 1 - 6 and Comparative Example 1 that the new preparation method provided by the present invention can not only react rapidly without an acid-binding agent, thus ingeniously eliminating the recovery step of the acid-binding agent, making the preparation method simpler and more convenient, but also successfully maintaining the high purity and high yield of the product while ensuring the reaction efficiency. This preparation method also makes the separation and purification operations of the reactants easier, significantly reducing the production cost, improving the reaction efficiency, and providing the possibility for large-scale industrial production. In addition, the new post-treatment method adopted by the present invention not only has a simple and clear operation process and simple and efficient steps, but also can ensure that the yield and purity of the final product, N-methyl-N-isopropylsulfamide, are maintained at a relatively high level. This provides a more efficient, environmentally friendly, and economical solution for the preparation of N-methyl-N-isopropylsulfamide.

Claims

1. A method for preparing N-methyl-N-isopropylsulfamide, characterized in that: It includes the following steps: S1: The mixture of N-methylisopropylamine and a solvent reacts with the mixture of sulfonyl chloride and a solvent in a microchannel continuous flow reactor I (5), and the tail gas is absorbed by a sodium hydroxide absorbent. After the reaction, the reaction solution is collected, washed with water, and the solvent is removed to obtain the intermediate N-methyl-N-isopropylaminosulfonyl chloride; S2: The N-methyl-N-isopropylaminosulfonyl chloride obtained in step S1 and ammonia water are simultaneously transported into a microchannel continuous flow reactor II (6) for reaction, and then post-treatment is carried out to obtain the target product.

2. The preparation method of N-methyl-N-isopropyl aminosulfonamide according to claim 1, characterized in that: The solvents in step S1 are all aprotic solvents, and the solvents are dichloromethane, dichloroethane, toluene or chloroform.

3. The preparation method of N-methyl-N-isopropyl aminosulfonamide according to claim 1, characterized in that: The molar ratio of N-methylisopropylamine, sulfonyl chloride and ammonia water is 1:1.0 - 2.0:2.0 - 10.

0.

4. The preparation method of N-methyl-N-isopropyl aminosulfonamide according to claim 1, characterized in that: In step S1, the mass ratio of N-methylisopropylamine to the solvent is 1:1.0 - 4.

0.

5. The preparation method of N-methyl-N-isopropylsulfamamide according to claim 1, characterized in that: In step S1, the mass ratio of sulfonyl chloride to the solvent is 1:1.0 - 4.

0.

6. The preparation method of N-methyl-N-isopropyl aminosulfonamide according to claim 1, characterized in that: In step S2, the mass concentration of ammonia water is 15 - 28%.

7. The preparation method of N-methyl-N-isopropyl amidosulfamide according to claim 1, characterized in that: The reaction temperature in step S1 is 5 - 20 °C, and the reaction residence time is 1 - 10 min.

8. The preparation method of N-methyl-N-isopropyl amidosulfamide according to claim 1, characterized in that: The reaction temperature in step S2 is 15 - 55 °C, and the reaction residence time is 5 - 15 min.

9. The preparation method of N-methyl-N-isopropyl amidosulfamide according to claim 1, characterized in that: The post-treatment method in step S2 is as follows: The reaction solution is cooled to 0 - 5 °C and stirred for 0.5 - 2 h, filtered, the filter cake is rinsed with a small amount of ice water, and vacuum dried at 40 - 50 °C for 12 - 36 h to obtain N-methyl-N-isopropylaminosulfonamide.

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