Preparation method of trifluoromethanesulfonamide

Abstract

The invention relates to a preparation method of trifluoromethanesulfonamide, which comprises the following steps: S1, introducing a refrigerant into a reactor to reduce the temperature of the reactor to 0 DEG C or below, introducing raw material ammonia water and a phase transfer catalyst into the reactor, introducing trifluoromethanesulfonyl fluoride into the ammonia water, and carrying out phase transfer reaction to obtain trifluoromethanesulfonamide; reacting trifluoromethanesulfonyl fluoride with excessive ammonia water to generate trifluoromethanesulfonamide ammonium salt and ammonium fluoride by-products; s2, raising the temperature to room temperature, discharging excessive ammonia gas, and adding acid into the reaction liquid to adjust the pH value to 2-3; and S3, extracting the reaction liquid by using an extracting agent, and combining and concentrating organic phases to obtain a trifluoromethanesulfonamide crude product. The method has the characteristics that the process is environment-friendly and simple, three wastes are easy to separate and recover, raw materials are cheap and easy to obtain, the reaction process is simple, no waste gas pollution is generated even if nitrogen protection is needed, the operation is easy, and the method is suitable for industrial production.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of fine chemical industry, and particularly relates to a preparation method of trifluoromethanesulfonamide. BACKGROUND

[0002] Trifluoromethanesulfonamide is an important fine chemical product, which is mainly used as an organic synthesis basic chemical reagent and an organic electrolyte additive in the field of battery production, and has good application in basic chemical research. Due to the special chemical structure of the anion part (CF3SO2)2N- of trifluoromethanesulfonamide, it has high electrochemical stability and conductivity, and can be used to improve the performance and stability of the battery, and has good application in the field of battery processing and production, and has great potential market and development prospect.

[0003] US8026391B2 discloses a perfluoroalkyl sulfonamide and a preparation method thereof, and a synthesis method of trifluoromethanesulfonamide is mainly trifluoromethanesulfonic anhydride and liquid ammonia method (as shown in chemical reaction path 1). The raw material cost of this process is high, the utilization rate of trifluoromethanesulfonyl is low, two molecules of trifluoromethanesulfonyl generate one molecule of trifluoromethanesulfonamide, one molecule of which is converted into trifluoromethanesulfonamide, and the other molecule is converted into ammonium trifluoromethanesulfonate. A recovery device is needed to recover and convert ammonium trifluoromethanesulfonate, which has high process cost. At the same time, this process method will produce corrosive acidic and alkaline waste liquid, which brings great trouble to the treatment of three wastes.

[0004] Chemical reaction path 1:

[0005] SUMMARY

[0006] In view of the high raw material cost of preparing trifluoromethanesulfonamide in the prior art and the generation of a large amount of three wastes in the reaction process, the present application provides a preparation method of trifluoromethanesulfonamide, which can avoid the use of high-cost and dangerous gas materials, and also reduces the emission of three wastes.

[0007] The technical scheme of the present application is:

[0008] A preparation method of trifluoromethanesulfonamide, comprising the following steps:

[0009] S1. A coolant is introduced into the reactor to reduce the temperature of the reactor to 0℃ or below, raw material ammonia water and a phase transfer catalyst are introduced into the reactor, trifluoromethanesulfonyl fluoride is introduced into the ammonia water, and trifluoromethanesulfonyl fluoride reacts with excess ammonia water to generate trifluoromethanesulfonamide ammonium salt and ammonium fluoride byproduct;

[0010] S2. The reaction is raised to room temperature, excess ammonia gas is discharged, and acid is added to the reaction liquid to adjust the pH to 2-3;

[0011] S3. Extract the reaction solution with an extractant, combine and concentrate the organic phases to obtain crude trifluoromethanesulfonamide.

[0012] Preferably, the phase transfer catalyst in S1 is one of tetrabutylammonium chloride, tetrabutylammonium fluoride, tetrabutylammonium bromide, 15-crown-5, and 18-crown-6;

[0013] The reaction was continuously stirred, and the reaction time was 16–46 h.

[0014] The reaction temperature is between -10 and 0℃.

[0015] Preferably, the molar ratio of trifluoromethanesulfonyl fluoride to ammonia in S1 is 1:8.9-30;

[0016] The mass ratio of phase transfer catalyst to ammonia is 1:10 to 100.

[0017] Preferably, the mass ratio of acid to trifluoromethanesulfonyl fluoride added to S2 is 1 to 10:1, and the acid is one of hydrochloric acid, sulfuric acid, and acetic acid; the mass concentration of hydrochloric acid is 36%, the mass concentration of sulfuric acid is 50%, and the mass concentration of acetic acid is 100%.

[0018] Preferably, the extractant in S3 is one of ethyl acetate, dichloromethane, carbon tetrachloride, and benzene.

[0019] Preferably, in step S3, the reaction solution is extracted with an extractant at least three times, and the volume ratio of the reaction solution to the extractant is 1:3 to 10.

[0020] Preferably, it also includes S4. The crude trifluoromethanesulfonamide is purified by chromatography and then recrystallized to obtain pure trifluoromethanesulfonamide.

[0021] Preferably, in step S4, purification is performed using a chromatography column with silica gel powder having a mesh size of 200–1000 mesh;

[0022] During the column chromatography purification process, the mobile phase is a mixture of ethyl acetate and petroleum ether, with a volume ratio of ethyl acetate to petroleum ether of 1:50 to 200.

[0023] After purification, the organic phase was evaporated to dryness using a rotary evaporator.

[0024] The temperature for vacuum distillation is 40℃ and the pressure is -0.1MPa.

[0025] Preferably, the solvent used for recrystallization in S4 is one or more of ethyl acetate, ethanol, and isopropanol.

[0026] The reaction equation for this invention is:

[0027] S1:

[0028]

[0029] S2:

[0030]

[0031] The beneficial effects of this invention are:

[0032] The process of this invention is highly safe, has low production cost, is easy to operate, allows for the recycling and treatment of reaction waste, has mild reaction conditions, and allows for the recycling and reuse of solvents generated during the reaction and purification. Conventional reaction vessels are sufficient, and the reaction yield is high.

[0033] In this invention, the reactants react completely, the wastewater is easy to discharge after the reaction, the post-treatment is simple, the solvent can be recycled, and pollution during the synthesis process is reduced, which is a green synthesis process.

[0034] This invention is low in cost and has a high raw material utilization rate. Compared with the original trifluoromethanesulfonic anhydride synthesis process, it has a high reaction conversion rate and does not generate a large amount of acidic waste gas. This method adopts a two-step synthesis, with a short process route and a relatively environmentally friendly and simple reaction process. The solvent and by-products can be recycled. This application has the advantages of environmentally friendly and simple process. The raw materials used in this invention are common chemical raw materials that are inexpensive and readily available. The reaction process is simple, the equipment is conventional reaction equipment, and the nitrogen protection does not generate waste gas pollution. It is easy to operate and suitable for industrial production. Detailed Implementation

[0035] Example 1

[0036] Step 1: Use a coolant to lower the temperature of the 1L three-necked flask to 0℃. Slowly introduce 543g (8.9mol, 9.0eq.) of ammonia water (concentration: 28%) and 54.3g (0.2mol, 0.02eq.) of tetrabutylammonium fluoride catalyst into the flask. Then introduce 152g (1.0mol, 1.0eq.) of trifluoromethanesulfonyl fluoride into the ammonia water and react at 0℃ for 16h.

[0037] Step 2: After the reaction is complete, slowly raise the temperature to 20°C to remove excess ammonia; then introduce 672g of 36% concentrated hydrochloric acid into the reaction solution to adjust the pH to 3.

[0038] Step 3: Extract three times with 3L of ethyl acetate, combine and concentrate the organic phases to obtain crude trifluoromethanesulfonamide;

[0039] Step four: Purification was performed using a chromatography column with 200-mesh silica gel powder. The mobile phase ratio (volume ratio) was ethyl acetate:petroleum ether = 1:50. After purification, the mobile phase mixture of ethyl acetate and petroleum ether was evaporated to dryness using a rotary evaporator at 40°C and -0.1 MPa. Recrystallization from isopropanol yielded 116.2 g of pure trifluoromethanesulfonamide with a purity of 99% and a yield of 78%.

[0040] Example 2

[0041] Step 1: Use a coolant to lower the temperature of the 5L three-necked flask to -5℃. Slowly introduce 1821g (30mol, 30eq.) of ammonia water (concentration: 28%) and 18.21g (0.06mol, 0.002eq.) of tetrabutylammonium chloride catalyst into the flask. Then introduce 152g (1.0mol, 1.0eq.) of trifluoromethanesulfonyl fluoride into the ammonia water and react at -5℃ for 46h.

[0042] Step 2: After the reaction is complete, slowly raise the temperature to 25°C to remove excess ammonia; then introduce 152g of 50% sulfuric acid into the reaction solution to adjust the pH to 2.

[0043] Step 3: Extract three times with 20L of dichloromethane, combine and concentrate the organic phases to obtain crude trifluoromethanesulfonamide;

[0044] Step four: Purification was performed using a chromatography column. The silica gel powder used for purification was 500 mesh, and the mobile phase ratio (volume ratio) was ethyl acetate:petroleum ether = 1:100. After purification, the mobile phase of ethyl acetate and petroleum ether was evaporated to dryness using a rotary evaporator at 40°C and -0.1 MPa. Recrystallization from ethyl acetate yielded 121.9 g of pure trifluoromethanesulfonamide with a purity of 98% and a yield of 82%.

[0045] Example 3

[0046] Step 1: Use a refrigerant to lower the temperature of the 5L three-necked flask to -10°C, and slowly introduce 1214g (20mol, 20eq.) of ammonia water (concentration: 28%) and 60.7g (0.16mol, 0.008eq.) of catalyst into the flask.

[0047] 18-crown-6 was then passed through ammonia water with 152 g (1.0 mol, 1.0 eq.) of trifluoromethanesulfonyl fluoride, and the reaction was carried out at -10 °C for 32 h.

[0048] Step 2: After the reaction is complete, slowly raise the temperature to 20°C to remove excess ammonia; then introduce 497g of 100% acetic acid into the reaction solution until the pH reaches 3.

[0049] Step 3: Extract three times with 10L of petroleum ether, combine and concentrate the organic phases, remove the petroleum ether, and obtain crude trifluoromethanesulfonamide;

[0050] Step four: Purification was performed using a chromatography column. The silica gel powder used for purification was 1000 mesh, and the mobile phase ratio (volume ratio) was ethyl acetate:petroleum ether = 1:200. After purification, the mobile phase of ethyl acetate and petroleum ether was evaporated to dryness using a rotary evaporator at 40℃ and -0.1 MPa. Recrystallization from ethanol yielded 129.6 g of pure trifluoromethanesulfonamide with a purity of 98% and a yield of 87%.

[0051] Comparative Example 1

[0052] The difference between this embodiment and Comparative Example 1 is that: in step S1, a refrigerant is used to lower the temperature in the 1L three-necked flask to 10°C;

[0053] 92.36 g of pure trifluoromethanesulfonamide was obtained, with a purity of 94% and a yield of 62%.

[0054] Comparative Example 2

[0055] The difference between this embodiment and Comparative Example 1 is that in step S2, concentrated hydrochloric acid with a concentration of 36% is introduced into the reaction solution to adjust the pH to 5;

[0056] 43.2 g of pure trifluoromethanesulfonamide was obtained, with a purity of 89% and a yield of 29%.

[0057] Comparative Example 3

[0058] The difference between this embodiment and Comparative Example 1 is that the catalyst in step S1 is replaced with Pd2(dba)3;

[0059] 15g of pure trifluoromethanesulfonamide was obtained, with a purity of 79% and a yield of 10.69%.

[0060] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A process for the preparation of triflimides, characterized in that: The method comprises the following steps: S1. Passing a refrigerant into a reactor to reduce the temperature of the reactor to below 0℃, passing raw ammonia water and a phase transfer catalyst into the reactor, and passing trifluoromethanesulfonyl fluoride into the ammonia water, so that the trifluoromethanesulfonyl fluoride reacts with excess ammonia water to generate trifluoromethanesulfonamide ammonium salt and ammonium fluoride by-product; S2. Raising the reaction to room temperature, discharging excess ammonia gas, and adding an acid into the reaction liquid to adjust the pH to 2-3; S3. Extracting the reaction liquid with an extractant, combining the organic phase, and concentrating to obtain a trifluoromethanesulfonamide crude product.

2. A process for the preparation of triflimides according to claim 1, characterized by: The phase transfer catalyst in S1 is one of tetrabutylammonium chloride, tetrabutylammonium fluoride, tetrabutylammonium bromide, 15-crown-5, and 18-crown-6; The reaction process is continuously stirred, and the reaction time is 16-46 h; The reaction temperature is between -10 and 0℃.

3. The method for preparing trifluoromethanesulfonamide according to claim 1, characterized in that: The mass ratio of trifluoromethanesulfonyl fluoride to ammonia water in S1 is 1:8.9-30; The mass ratio of the phase transfer catalyst to ammonia water is 1:10-100.

4. The method of claim 1, wherein: The mass ratio of the acid to trifluoromethanesulfonyl fluoride in S2 is 1-10:1, and the acid is one of hydrochloric acid, sulfuric acid, and acetic acid; the mass concentration of the hydrochloric acid is 36%, the mass concentration of the sulfuric acid is 50%, and the mass concentration of the acetic acid is 100%.

5. The method of claim 1, wherein: The extractant in S3 is one of ethyl acetate, dichloromethane, carbon tetrachloride, and benzene.

6. The method of claim 1, wherein: The reaction liquid is extracted with the extractant for no less than 3 times, and the volume ratio of the reaction liquid to the extractant is 1:3-10.

7. The method for preparing trifluoromethanesulfonamide according to claim 1, characterized in that: The method further comprises S4. The trifluoromethanesulfonamide crude product is purified by a chromatographic column and then recrystallized to obtain a trifluoromethanesulfonamide pure product.

8. The method of claim 7, wherein the triflimide is prepared by the reaction of a triflic acid with a base in the presence of a solvent. The chromatographic column purification in S4 uses silica gel powder with a mesh size of 200-1000 mesh; The mobile phase in the chromatographic column purification process is a mixture of ethyl acetate and petroleum ether, and the volume ratio of ethyl acetate to petroleum ether is 1:50-200; The organic phase is evaporated to dryness by a rotary evaporator at the end of the purification; The temperature of the reduced pressure distillation is 40℃, and the pressure is -0.1 MPa.

9. The method of claim 7, wherein the triflimide is prepared by the reaction of a triflic acid with a base in the presence of a solvent. The recrystallization in S4 uses one or more of ethyl acetate, ethanol, and isopropanol as a solvent.

Images