A preparation method of N,N-dimethyl trifluoromethanesulfonamide

Abstract

The invention discloses a method for preparing N, N-dimethyl trifluoromethanesulfonamide, using a dynamic tubular reactor, a stirring screw is provided in the dynamic tubular reactor, trifluoromethanesulfonyl fluoride and dimethylamine reacted in the dynamic tubular reactor are both in liquid state, the dynamic tubular reactor input end to the dynamic tubular reactor output end are successively divided into a cooling section, a heat preservation section, and a heating section, the temperature in the cooling section is 50°C~30°C, the temperature in the heating section is 30°C~50°C, the mass flow ratio of trifluoromethanesulfonyl fluoride and dimethylamine input is controlled at 1:0.65~0.75; the retention time of the reaction material in the dynamic tubular reactor is controlled at 45min~75min; the material output by the dynamic tubular reactor enters a centrifugal extraction mechanism for water washing, and a product is obtained after washing. The advantages of the present invention are: high conversion rate, high yield, high purity, can be directly used as an electrolyte additive, and are suitable for industrial production.

Description

Technical Field

[0001] The invention relates to the technical field of chemical synthesis, and in particular to a method for preparing N,N-dimethyltrifluoromethanesulfonamide. Background Art

[0002] Lithium metal batteries and lithium-oxygen batteries have become a hot topic in the research of the new generation of batteries due to their advantages such as higher energy density, long cycle life, high safety and good sustainability.

[0003] Traditional solvents such as carbonates, ethylene glycol dimethyl ether, dimethyl sulfoxide, and N,N-dimethylformamide are very unstable in the highly active environment inside lithium metal batteries and lithium-oxygen batteries, and are prone to forming poor solid electrolyte interface films (SEI), thereby reducing battery performance or causing failures. However, N,N-dimethyltrifluoromethanesulfonamide is a good substitute for carbonate solvents due to its higher electrochemical stability, ability to form a stable electrode interface, and low flammability, and has very broad application prospects.

[0004] There is no literature report on large-scale production of N,N-dimethyltrifluoromethanesulfonamide. The literature related to laboratory synthesis of N,N-dimethyltrifluoromethanesulfonamide is as follows.

[0005] (1) Trifluoromethanesulfonyl fluoride reacts with dimethylamine (liquid dimethylamine or dimethylamine aqueous solution), using dimethylamine or triethylamine as an acid-binding agent (CN1289765, Russ. J. Gen. Chem., 2009, 79, 315, CN113801040, CN115703722), and in the post-treatment process, it is necessary to use highly dangerous ether as an extractant or additionally use alcohols as solvents and use sodium alcoholate to regenerate dimethylamine;

[0006] (2) Trifluoromethanesulfonyl chloride reacts with dimethylamine (liquid dimethylamine or an organic solution of dimethylamine), using dimethylamine or triethylamine as an acid binding agent (Chem, 2019, 5, 2630, J. Fluorine Chem., 2013, 147, 56, US2023174469, CN118354997);

[0007] (3) Trifluoromethanesulfonamide reacts with iodomethane to undergo N-methylation reaction (J. Fluorine Chem., 2010, 131, 761).

[0008] The above three preparation methods have the following defects: 1. They are usually only suitable for laboratory preparation and cannot be scaled up to large-scale production. 2. Other reagents, such as extractants, organic solvents, etc., are required in the reaction. The use of these solvents not only increases production costs, but also results in the purity of the final product being only 99% at most, and cannot reach 99.9%, so it cannot be used directly as an electrolyte additive. Summary of the invention

[0009] The technical problem to be solved by the present invention is to provide a method for preparing N,N-dimethyltrifluoromethanesulfonamide, which has high conversion rate, high yield and high purity, can be directly used as an electrolyte additive, and is suitable for industrial production.

[0010] In order to solve the above problems, the technical scheme adopted by the present invention is: a method for preparing N,N-dimethyl trifluoromethanesulfonamide, using trifluoromethanesulfonyl fluoride and dimethylamine as reaction raw materials, using a dynamic tubular reactor, the two ends of the dynamic tubular reactor are respectively the dynamic tubular reactor input end and the dynamic tubular reactor output end, the dynamic tubular reactor is provided with a stirring screw that can transport the material from the dynamic tubular reactor input end to the dynamic tubular reactor output end, the trifluoromethanesulfonyl fluoride and dimethylamine that enter the dynamic tubular reactor for reaction are both in liquid state, and the dynamic tubular reactor is divided into a cooling section, a heat preservation section and a cooling section from the dynamic tubular reactor input end to the dynamic tubular reactor output end. The temperature in the dynamic tubular reactor of the heating section, the cooling section is controlled at -50°C to -30°C, the temperature in the dynamic tubular reactor of the heating section is controlled at 30°C to 50°C, the mass flow ratio of trifluoromethanesulfonyl fluoride to dimethylamine input is controlled at 1:0.65-0.75; the retention time of the reaction material in the dynamic tubular reactor is controlled at 45min-75min; the material output from the output end of the dynamic tubular reactor enters a centrifugal extraction mechanism for water washing, the centrifugal extraction mechanism comprises at least two stages of centrifugal extractors arranged in series; after washing in each stage of the centrifugal extractors arranged in series, the N,N-dimethyltrifluoromethanesulfonamide product is obtained.

[0011] Furthermore, in the aforementioned method for preparing N,N-dimethyl trifluoromethanesulfonamide, liquid trifluoromethanesulfonyl fluoride is provided by a liquid trifluoromethanesulfonyl fluoride supply mechanism, the liquid trifluoromethanesulfonyl fluoride supply mechanism comprises: a trifluoromethanesulfonyl fluoride storage tank for storing trifluoromethanesulfonyl fluoride, the trifluoromethanesulfonyl fluoride storage tank is arranged in a cooling device, the trifluoromethanesulfonyl fluoride in the trifluoromethanesulfonyl fluoride storage tank is in liquid state under the cooling effect of the cooling device, the trifluoromethanesulfonyl fluoride storage tank is provided with a first output pipe, the lower end of the first output pipe is provided with a first output pipe, and the lower end of the first output pipe is provided with a first output pipe. The first end of the first output pipe extends into the bottom of the trifluoromethanesulfonyl fluoride storage tank, the upper end of the first output pipe is connected to the trifluoromethanesulfonyl fluoride delivery pipe coated with a heat-insulating material, the trifluoromethanesulfonyl fluoride delivery pipe is connected to the input end of the dynamic tubular reactor, and the trifluoromethanesulfonyl fluoride delivery pipe is provided with a first back pressure valve, a first mass flow meter, and a first check valve in sequence along the delivery direction of the trifluoromethanesulfonyl fluoride; under the action of the liquid trifluoromethanesulfonyl fluoride delivery power mechanism, the liquid trifluoromethanesulfonyl fluoride is delivered to the tubular reactor through the first output pipe and the trifluoromethanesulfonyl fluoride delivery pipe.

[0012] Furthermore, in the aforementioned method for preparing N,N-dimethyltrifluoromethanesulfonamide, the pressure of the first back pressure valve is adjusted to 0.2~0.6 MPa.

[0013] Furthermore, in the aforementioned method for preparing N,N-dimethyltrifluoromethanesulfonamide, liquid dimethylamine is provided by a liquid dimethylamine supply mechanism, the liquid dimethylamine supply mechanism comprising: a dimethylamine storage tank for storing liquid dimethylamine, the dimethylamine storage tank being arranged in a cooling device, the dimethylamine in the dimethylamine storage tank being in liquid state under the cooling effect of the cooling device, a second output pipe being arranged in the dimethylamine storage tank, the lower end of the second output pipe extending into the bottom of the dimethylamine storage tank, the upper end of the second output pipe being connected to a dimethylamine delivery pipe coated with a heat-insulating material, the dimethylamine delivery pipe being connected to an input end of a dynamic tubular reactor, a second back pressure valve, a second mass flowmeter, and a second check valve being arranged on the dimethylamine delivery pipe in sequence along the delivery direction of the liquid dimethylamine; under the action of the liquid dimethylamine delivery power mechanism, the liquid dimethylamine is delivered to the dynamic tubular reactor through the second output pipe and the dimethylamine delivery pipe.

[0014] Furthermore, in the aforementioned method for preparing N,N-dimethyltrifluoromethanesulfonamide, the pressure of the second back pressure valve is adjusted to 0.2~0.6 MPa.

[0015] Furthermore, in the aforementioned method for preparing N,N-dimethyl trifluoromethanesulfonamide, the liquid trifluoromethanesulfonyl fluoride delivery mechanism and the liquid dimethylamine delivery mechanism include: a nitrogen input main pipe, a pressure reducing valve is arranged on the nitrogen input main pipe, the nitrogen input main pipe is connected to a first nitrogen input branch pipe with a first branch check valve and a second nitrogen input branch pipe with a second branch check valve, the first nitrogen input branch pipe extends into the trifluoromethanesulfonyl fluoride storage tank, the second nitrogen input branch pipe is connected to the first nitrogen input branch pipe with a first branch check valve, The branch pipe extends into the dimethylamine storage tank; nitrogen enters the trifluoromethanesulfonyl fluoride storage tank through the nitrogen input main pipe and the first nitrogen input branch pipe, so that liquid trifluoromethanesulfonyl fluoride is transported to the dynamic tubular reactor through the first output pipe and the trifluoromethanesulfonyl fluoride delivery pipe by means of pressurization; nitrogen enters the dimethylamine storage tank through the nitrogen input main pipe and the second nitrogen input branch pipe, so that liquid dimethylamine is transported to the dynamic tubular reactor through the second output pipe and the dimethylamine delivery pipe by means of pressurization.

[0016] Furthermore, in the aforementioned method for preparing N,N-dimethyltrifluoromethanesulfonamide, the output end of the dynamic tubular reactor is connected to a collecting tank, and the material in the collecting tank is transported to a centrifugal extraction mechanism by a delivery pump.

[0017] Furthermore, in the aforementioned method for preparing N,N-dimethyltrifluoromethanesulfonamide, the material in the collecting tank sequentially enters each stage of the centrifugal extractors arranged in series for washing, and the washing water sequentially enters the centrifugal extractors arranged in series in reverse direction, and the flow direction of the material to be washed in the centrifugal extraction mechanism is opposite to the flow direction of the washing water in the centrifugal extraction mechanism, the washed material is output from the last stage of the centrifugal extractor, and the wastewater generated by washing is discharged from the first stage of the centrifugal extractor.

[0018] Furthermore, in the aforementioned method for preparing N,N-dimethyltrifluoromethanesulfonamide, 2 to 6 stages of centrifugal extractors are arranged in series in the centrifugal extraction mechanism. The more stages there are, the more water consumption can be reduced, and the water content of the finished product can also be further reduced.

[0019] Furthermore, in the aforementioned method for preparing N,N-dimethyltrifluoromethanesulfonamide, the centrifugal extraction mechanism comprises four-stage centrifugal extractors arranged in series, and the volume flow ratio of the material to be washed to deionized water is 1:(0.3~0.5).

[0020] Furthermore, in the aforementioned method for preparing N,N-dimethyltrifluoromethanesulfonamide, a cooling jacket is provided on the dynamic tubular reactor of the cooling section, a refrigerant with a temperature of -50°C to -30°C is passed into the cooling jacket, the cooling jacket input port is arranged close to the insulation section, and the cooling jacket output port is arranged close to the input end of the dynamic tubular reactor; an insulation layer is provided on the outer wall of the dynamic tubular reactor of the insulation section; a heating jacket is provided on the dynamic tubular reactor of the heating section, water with a temperature of 30°C to 50°C is passed into the heating jacket, the heating jacket input port is arranged close to the output end of the dynamic tubular reactor, and the heating jacket output port is arranged close to the insulation section.

[0021] Furthermore, in the aforementioned method for preparing N,N-dimethyltrifluoromethanesulfonamide, the rotation speed of the stirring screw is controlled at 80-120 rpm.

[0022] Furthermore, in the aforementioned method for preparing N,N-dimethyltrifluoromethanesulfonamide, the length ratio of the cooling section, the insulation section, and the heating section is 2:4:4.

[0023] Furthermore, in the aforementioned method for preparing N,N-dimethyltrifluoromethanesulfonamide, the pressure in the dynamic tubular reactor is controlled at 0.4 MPa~0.6 MPa.

[0024] Furthermore, in the aforementioned method for preparing N,N-dimethyltrifluoromethanesulfonamide, the water used for washing is deionized water.

[0025] The advantages of the present invention are as follows: 1. A dynamic tubular reactor is adopted, and the dynamic tubular reactor is divided into three different temperature zones: a cooling section, a heat preservation section, and a heating section. The cooling section and the heating section can be temperature controlled separately, wherein the temperature in the dynamic tubular reactor of the cooling section is controlled at -50°C to -30°C. Low temperature control in this section can avoid the reaction materials from reacting violently at the input end of the dynamic tubular reactor, ensure that the materials are mixed evenly first, thereby effectively avoiding the occurrence of side reactions, and effectively controlling the reaction process, so that the evenly mixed materials fully react after entering the heat preservation section area, and further fully react in the heating section. The three sections with different temperatures are set to make the reaction fully complete, greatly improving the conversion rate, and no organic solvent is needed to assist, which not only greatly reduces the difficulty of purification, effectively reduces the production cost, but also greatly improves the purity of the finished product. 2. The crude product output from the output end of the dynamic tubular reactor only needs to be washed in a centrifugal extractor, which can greatly improve the purity of the product, and no other purification organic solvent is needed. The purification method is very simple, and the countercurrent method of the material to be washed and the washing water can effectively save the amount of water used, thereby further reducing the production cost. 3. The entire process is very simple, with a high conversion rate, almost 100% conversion, and a high yield, with the product yield being above 92%; the purity is high, with the product purity reaching 99.9%, and the moisture content being less than 100ppm. It can be directly used as an electrolyte additive and is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The present invention is a schematic structural diagram of a dynamic tubular reactor used in a method for preparing N,N-dimethyltrifluoromethanesulfonamide.

[0027] Figure 2 This is the nuclear magnetic resonance fluorine spectrum of the product N,N-dimethyltrifluoromethanesulfonamide in Example 1. DETAILED DESCRIPTION

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] First, the specific structure and working process of the reaction device are introduced. Figure 1 As shown, a dynamic tubular reactor 4 is used, and the two ends of the dynamic tubular reactor 4 are respectively a dynamic tubular reactor input end 401 and a dynamic tubular reactor output end 402. The dynamic tubular reactor 4 is provided with a stirring screw 46 that can continuously transport materials from the dynamic tubular reactor input end 401 to the dynamic tubular reactor output end 402. The trifluoromethanesulfonyl fluoride and dimethylamine entering the dynamic tubular reactor 4 for reaction are both in liquid state.

[0030] The liquid trifluoromethanesulfonyl fluoride is provided by a liquid trifluoromethanesulfonyl fluoride supply mechanism 2, and the liquid trifluoromethanesulfonyl fluoride supply mechanism 2 comprises: a trifluoromethanesulfonyl fluoride storage tank 21 for storing trifluoromethanesulfonyl fluoride, the trifluoromethanesulfonyl fluoride storage tank 21 is arranged in a cooling device, and the trifluoromethanesulfonyl fluoride in the trifluoromethanesulfonyl fluoride storage tank 21 is in liquid state under the cooling effect of the cooling device. A first output pipe 26 is arranged in the trifluoromethanesulfonyl fluoride storage tank 21, the lower end of the first output pipe 26 extends into the bottom of the trifluoromethanesulfonyl fluoride storage tank 21, the upper end of the first output pipe 26 is connected to a trifluoromethanesulfonyl fluoride delivery pipe 25 coated with a heat-insulating material, the trifluoromethanesulfonyl fluoride delivery pipe 25 is connected to the input end 401 of the dynamic tubular reactor, and a first back pressure valve 22, a first mass flowmeter 23, and a first check valve 24 are arranged on the trifluoromethanesulfonyl fluoride delivery pipe 25 in sequence along the delivery direction of the trifluoromethanesulfonyl fluoride. The pressure of the first back pressure valve 22 is adjusted to 0.2-0.6 MPa. The first back pressure valve 22 is provided to ensure that the trifluoromethanesulfonyl fluoride in the trifluoromethanesulfonyl fluoride delivery pipe 25 is in liquid state.

[0031] Liquid dimethylamine is provided by a liquid dimethylamine supply mechanism 3, which includes: a dimethylamine storage tank 31 for storing liquid dimethylamine, the dimethylamine storage tank 31 is arranged in a cooling device, and the dimethylamine in the dimethylamine storage tank 31 is in liquid state under the cooling effect of the cooling device. A second output pipe 36 is arranged in the dimethylamine storage tank 31, the lower end of the second output pipe 36 extends into the bottom of the dimethylamine storage tank 31, and the upper end of the second output pipe 36 is connected to a dimethylamine delivery pipe 35 coated with a heat-insulating material, and the dimethylamine delivery pipe 35 is connected to the input end 401 of the dynamic tubular reactor. A second back pressure valve 32, a second mass flow meter 33, and a second check valve 34 are arranged on the dimethylamine delivery pipe 35 in sequence along the delivery direction of the liquid dimethylamine. The pressure of the second back pressure valve 32 is adjusted to 0.2-0.6 MPa. The second back pressure valve 32 is provided to ensure that the dimethylamine in the dimethylamine delivery pipe 35 is in liquid state.

[0032] The transport power mechanism of trifluoromethanesulfonyl fluoride and dimethylamine includes: a nitrogen input main pipe 1, a pressure reducing valve 11 is arranged on the nitrogen input main pipe 1, and the nitrogen input main pipe 1 is connected with a first nitrogen input branch pipe 12 with a first branch pipe check valve 121 and a second nitrogen input branch pipe 13 with a second branch pipe check valve 131. The first nitrogen input branch pipe 12 extends into the trifluoromethanesulfonyl fluoride storage tank 21, and the second nitrogen input branch pipe 13 extends into the dimethylamine storage tank 31. Nitrogen enters the trifluoromethanesulfonyl fluoride storage tank 21 through the nitrogen input main pipe 1 and the first nitrogen input branch pipe 12, so that liquid trifluoromethanesulfonyl fluoride is transported to the dynamic tubular reactor 4 through the first output pipe 26 and the trifluoromethanesulfonyl fluoride delivery pipe 25 by means of pressurization. Nitrogen enters the dimethylamine storage tank 31 through the nitrogen input main pipe 1 and the second nitrogen input branch pipe 13, so that liquid dimethylamine is transported to the dynamic tubular reactor 4 through the second output pipe 36 and the dimethylamine delivery pipe 35 by means of pressurization.

[0033] The dynamic tubular reactor 4 is divided into a cooling section 41, a heat preservation section 42, and a heating section 43 from the dynamic tubular reactor input end 401 to the dynamic tubular reactor output end 402, and the length ratio of the cooling section 41, the heat preservation section 42, and the heating section 43 is 2:4:4. The temperature in the dynamic tubular reactor 4 of the cooling section 41 is controlled at -50°C to -30°C, and the temperature in the dynamic tubular reactor 4 of the heating section 43 is controlled at 30°C to 50°C. The setting of the cooling section 41 and the temperature in the dynamic tubular reactor 4 of the cooling section 41 are controlled at -50°C to -30°C, and the purpose is to: avoid the reaction materials from reacting violently at the dynamic tubular reactor input end 401, let the reaction materials entering the dynamic tubular reactor 4 be mixed evenly first, reduce the occurrence of side reactions, and effectively control the reaction process. The heat preservation section 42 serves as a transition and connection between the cooling section 41 and the heating section 43, and the reaction materials after mixing evenly react in the heat preservation section 42. The heating section 43 controls the temperature at 30° C. to 50° C., the purpose of which is to promote further complete reaction of the materials.

[0034] The dynamic tubular reactor 4 of the cooling section 41 is provided with a cooling jacket 411, into which a refrigerant with a temperature of -50°C to -30°C is passed, the cooling jacket input port 412 is arranged near the heat preservation section 42, and the cooling jacket output port 413 is arranged near the dynamic tubular reactor input end 401. The outer wall of the dynamic tubular reactor 4 of the heat preservation section 42 is provided with a heat preservation layer 421. The dynamic tubular reactor 4 of the heating section 43 is provided with a heating jacket 431, into which water with a temperature of 30°C to 50°C is passed, the heating jacket input port 432 is arranged near the dynamic tubular reactor output end 402, and the heating jacket output port 433 is arranged near the heat preservation section 42.

[0035] The mass flow ratio of trifluoromethanesulfonyl fluoride to dimethylamine input is controlled at 1:0.65-0.75. The retention time of the reaction material in the dynamic tubular reactor 4 is controlled at 45min-75min. The output end 402 of the dynamic tubular reactor is connected to a collection tank 5, and the material output from the output end 402 of the dynamic tubular reactor is temporarily stored in the collection tank 5. The material in the collection tank 5 is transported to the centrifugal extraction mechanism 8 by the delivery pump 6.

[0036] The centrifugal extraction mechanism 8 includes at least two stages of centrifugal extractors arranged in series, and 2 to 6 stages of centrifugal extractors are arranged in series in the centrifugal extraction mechanism. The more stages there are, the less water consumption can be used, thereby further reducing the moisture in the product. The specification only takes a four-stage centrifugal extractor as an example for explanation. The four-stage centrifugal extractors are connected in series in sequence, and the four-stage centrifugal extractors are sequentially arranged along the flow direction of the material to be washed, namely, a first-stage centrifugal extractor 81, a second-stage centrifugal extractor 82, a third-stage centrifugal extractor 83, and a fourth-stage centrifugal extractor 84; each stage of the centrifugal extractor is provided with a light phase inlet, a light phase outlet, a heavy phase inlet, and a heavy phase outlet. Along the direction from the input end centrifugal extractor to the output end centrifugal extractor, the light phase outlet of the previous stage of each adjacent two centrifugal extractors is connected to the light phase inlet of the next stage, and the heavy phase inlet of the previous stage is connected to the heavy phase outlet of the next stage. The material to be washed output by the delivery pump 6 enters from the light phase inlet of the first-stage centrifugal extractor, that is, from the first-stage light phase inlet 811 of the first-stage centrifugal extractor 81, and is washed in each stage of the centrifugal extractor arranged in series to obtain the N,N-dimethyl trifluoromethanesulfonamide product. In this embodiment, the fourth-stage light phase outlet 841 of the fourth-stage centrifugal extractor 84 outputs the product. The water used for washing is input from the heavy phase inlet of the last-stage centrifugal extractor, that is, from the fourth-stage heavy phase inlet 842 of the fourth-stage centrifugal extractor 84, and is pumped by the water pump 7 in this embodiment. The wastewater generated by washing is output from the heavy phase outlet of the first-stage centrifugal extractor, that is, from the first-stage heavy phase outlet 812 of the first-stage centrifugal extractor 81. The material to be washed has an opposite flow direction to the water used for washing, which can effectively save water, reduce the amount of water used for washing, and thus reduce production costs.

[0037] In the following embodiments, the length ratio of the cooling section, the heat preservation section, and the heating section is 2:4:4, and a centrifugal extraction mechanism with four-stage centrifugal extractors connected in series is used for cleaning.

[0038] Embodiment 1: Adjust the pressure reducing valve 11 to keep the pressure in the trifluoromethanesulfonyl fluoride storage tank 21 and the dimethylamine storage tank 31 within the range of 0.7-0.8 MPa, the trifluoromethanesulfonyl fluoride storage tank 21 is cooled to -30°C, and the dimethylamine storage tank 31 is cooled to 0°C. The first back pressure valve 22 and the second back pressure valve 32 are set to 0.6 MPa, and the mass flow ratio of trifluoromethanesulfonyl fluoride to dimethylamine is controlled to be 1:0.7. A -30°C freezing liquid is introduced into the cooling jacket 411 of the dynamic tubular reactor 4, and 50°C warm water is introduced into the heating jacket 431. The pressure in the dynamic tubular reactor 4 is 0.6 MPa, the speed of the stirring screw 46 is 100 rpm, and the residence time is 65 minutes. Deionized water is used as the washing liquid, and the material temporarily stored in the collecting tank 5 is extracted and washed in the centrifugal extraction mechanism to remove water-soluble impurities, and no emulsification phenomenon occurs during the process. The material to be washed and deionized water are pumped into the centrifugal extraction mechanism at a volume flow ratio of 1:0.5, and N,N-dimethyl trifluoromethanesulfonamide product is obtained from the fourth-stage light phase outlet 841 with a yield of 98.7%, a purity of 99.9%, and a moisture content of 87 ppm. Figure 2 shown.

[0039] Embodiment 2: Adjust the pressure reducing valve 11 to keep the pressure in the trifluoromethanesulfonyl fluoride storage tank 21 and the dimethylamine storage tank 31 within the range of 0.7-0.8 MPa, the trifluoromethanesulfonyl fluoride storage tank 21 is cooled to -40°C, and the dimethylamine storage tank 31 is cooled to 0°C. The first back pressure valve 22 and the second back pressure valve 32 are set to 0.4 MPa, and the mass flow ratio of trifluoromethanesulfonyl fluoride to dimethylamine is controlled to be 1:0.7. A -40°C freezing liquid is introduced into the cooling jacket 411 of the dynamic tubular reactor 4, and 40°C warm water is introduced into the heating jacket 431. The pressure in the dynamic tubular reactor 4 is 0.4 MPa, the speed of the stirring screw 46 is 90 rpm, and the residence time is 55 minutes. Using deionized water as the washing liquid, the material temporarily stored in the collecting tank 5 is extracted and washed in the centrifugal extraction mechanism to remove water-soluble impurities, and no emulsification phenomenon occurs during the process. The material to be washed and deionized water are pumped into the centrifugal extraction mechanism at a volume flow ratio of 1:0.5, and N,N-dimethyltrifluoromethanesulfonamide product is obtained from the fourth-stage light phase outlet 841 with a yield of 96.1%, a purity of 99.9%, and a moisture content of 92 ppm.

[0040] Embodiment 3: Adjust the pressure reducing valve 11 to keep the pressure in the trifluoromethanesulfonyl fluoride storage tank 21 and the dimethylamine storage tank 31 within the range of 0.7-0.8 MPa, the trifluoromethanesulfonyl fluoride storage tank 21 is cooled to -50°C, and the dimethylamine storage tank 31 is cooled to 0°C. The first back pressure valve 22 and the second back pressure valve 32 are set to 0.2 MPa, and the mass flow ratio of trifluoromethanesulfonyl fluoride to dimethylamine is controlled to be 1:0.65. A -50°C freezing liquid is introduced into the cooling jacket 411 of the dynamic tubular reactor 4, and 30°C warm water is introduced into the heating jacket 431. The pressure in the dynamic tubular reactor 4 is 0.2 MPa, the speed of the stirring screw 46 is 100 rpm, and the residence time is 45 minutes. Using deionized water as the washing liquid, the material temporarily stored in the collecting tank 5 is extracted and washed in the centrifugal extraction mechanism to remove water-soluble impurities, and no emulsification phenomenon occurs during the process. The material to be washed and deionized water are pumped into the centrifugal extraction mechanism at a volume flow ratio of 1:0.4, and N,N-dimethyltrifluoromethanesulfonamide product is obtained from the fourth-stage light phase outlet 841 with a yield of 92.7%, a purity of 99.9%, and a moisture content of 90 ppm.

[0041] Embodiment 4: Adjust the pressure reducing valve 11 to keep the pressure in the trifluoromethanesulfonyl fluoride storage tank 21 and the dimethylamine storage tank 31 within the range of 0.7-0.8 MPa, the trifluoromethanesulfonyl fluoride storage tank 21 is cooled to -50°C, and the dimethylamine storage tank 31 is cooled to 0°C. The first back pressure valve 22 and the second back pressure valve 32 are set to 0.6 MPa, and the mass flow ratio of trifluoromethanesulfonyl fluoride to dimethylamine is controlled to be 1:0.65. A -50°C freezing liquid is introduced into the cooling jacket 411 of the dynamic tubular reactor 4, and 30°C warm water is introduced into the heating jacket 431. The pressure in the dynamic tubular reactor 4 is 0.6 MPa, the speed of the stirring screw 46 is 110 rpm, and the residence time is 50 minutes. Using deionized water as the washing liquid, the material temporarily stored in the collecting tank 5 is extracted and washed in the centrifugal extraction mechanism to remove water-soluble impurities, and no emulsification phenomenon occurs during the process. The material to be washed and deionized water are pumped into the centrifugal extraction mechanism at a volume flow ratio of 1:0.4, and N,N-dimethyltrifluoromethanesulfonamide product is obtained from the fourth-stage light phase outlet 841 with a yield of 94.2%, a purity of 99.9%, and a moisture content of 94 ppm.

[0042] Embodiment 5: Adjust the pressure reducing valve 11 to keep the pressure in the trifluoromethanesulfonyl fluoride storage tank 21 and the dimethylamine storage tank 31 within the range of 0.7-0.8 MPa, the trifluoromethanesulfonyl fluoride storage tank 21 is cooled to -30°C, and the dimethylamine storage tank 31 is cooled to 0°C. The first back pressure valve 22 and the second back pressure valve 32 are set to 0.2 MPa, and the mass flow ratio of trifluoromethanesulfonyl fluoride to dimethylamine is controlled to be 1: 0.75. A -30°C freezing liquid is introduced into the cooling jacket 411 of the dynamic tubular reactor 4, and 50°C warm water is introduced into the heating jacket 431. The pressure in the dynamic tubular reactor 4 is 0.2 MPa, the speed of the stirring screw 46 is 120 rpm, and the residence time is 60 minutes. Using deionized water as the washing liquid, the material temporarily stored in the collecting tank 5 is extracted and washed in the centrifugal extraction mechanism to remove water-soluble impurities, and no emulsification phenomenon occurs during the process. The material to be washed and deionized water are pumped into the centrifugal extraction mechanism at a volume flow ratio of 1:0.3, and N,N-dimethyltrifluoromethanesulfonamide product is obtained from the fourth-stage light phase outlet 841 with a yield of 95.8%, a purity of 99.9%, and a moisture content of 88 ppm.

[0043] Embodiment 6: Adjust the pressure reducing valve 11 to keep the pressure in the trifluoromethanesulfonyl fluoride storage tank 21 and the dimethylamine storage tank 31 within the range of 0.7-0.8 MPa, the trifluoromethanesulfonyl fluoride storage tank 21 is cooled to -50°C, and the dimethylamine storage tank 31 is cooled to 0°C. The first back pressure valve 22 and the second back pressure valve 32 are set to 0.6 MPa, and the mass flow ratio of trifluoromethanesulfonyl fluoride to dimethylamine is controlled to be 1:0.75. A -50°C freezing liquid is introduced into the cooling jacket 411 of the dynamic tubular reactor 4, and 50°C warm water is introduced into the heating jacket 431. The pressure in the dynamic tubular reactor 4 is 0.6 MPa, the speed of the stirring screw 46 is 80 rpm, and the residence time is 75 minutes. Using deionized water as the washing liquid, the material temporarily stored in the collecting tank 5 is extracted and washed in the centrifugal extraction mechanism to remove water-soluble impurities, and no emulsification phenomenon occurs during the process. The material to be washed and deionized water are pumped into the centrifugal extraction mechanism at a volume flow ratio of 1:0.3, and N,N-dimethyltrifluoromethanesulfonamide product is obtained from the fourth-stage light phase outlet 841 with a yield of 99.1%, a purity of 99.9%, and a moisture content of 92 ppm.

[0044] Comparative Example 1: This example was carried out under the conditions of Example 1, except that the residence time of the reaction material in the dynamic reactor 4 was 30 minutes. The yield was 84.3%, the purity was 99.8%, and the moisture content was 86 ppm.

[0045] It can be seen from Comparative Example 1 that the residence time of the reaction materials in the dynamic reactor 4 is too short, resulting in a significant decrease in yield and purity.

[0046] Comparative Example 2: This example was carried out under the conditions of Example 1, except that the residence time of the reaction material in the dynamic reactor was 90 minutes. The yield was 99.0%, the purity was 99.9%, and the moisture content was 85 ppm.

[0047] It can be seen from Comparative Example 2 that the yield and purity do not change much when the residence time is further extended.

[0048] Comparative Example 3: This example was carried out under the conditions of Example 1, except that the temperature in the dynamic tubular reactor 4 of the cooling section 41 was controlled at -20°C. The yield was 98.2%, the purity was 99.8%, and the moisture content was 93 ppm.

[0049] It can be seen from Comparative Example 3 that when the temperature of the cooling section is lowered to -20°C, both the yield and purity decrease.

[0050] Comparative Example 4: This example was carried out under the conditions of Example 1, except that the temperature in the dynamic tubular reactor 4 of the cooling section 41 was controlled at -10°C. The yield was 97.8%, the purity was 99.5%, and the moisture content was 89 ppm.

[0051] It can be seen from Comparative Example 4 that when the temperature of the cooling section is lowered to -10°C, both the yield and purity are significantly reduced.

[0052] It can be seen from the above embodiments that the advantages of the present invention are: 1. A dynamic tubular reactor 4 is adopted, and the dynamic tubular reactor 4 is divided into three different temperature zones: a cooling section, a heat preservation section, and a heating section. The cooling section and the heating section can be temperature-controlled separately, wherein the temperature in the dynamic tubular reactor 4 of the cooling section 41 is controlled at -50°C~-30°C. Low temperature control in this section can avoid the reaction materials from reacting violently at the input end 401 of the dynamic tubular reactor, ensuring that the materials are mixed evenly first, thereby effectively avoiding the occurrence of side reactions, and effectively controlling the reaction process, so that the evenly mixed materials enter the heat preservation section area and react fully, and further react fully in the heating section. The three sections with different temperatures are set to make the reaction fully and completely, greatly improving the conversion rate, and no organic solvent is required to assist, which not only greatly reduces the difficulty of purification, effectively reduces production costs, but also greatly improves the purity of the finished product. 2. The crude product output from the output end of the dynamic tubular reactor only needs to be washed in a centrifugal extractor, which can greatly improve the purity of the product. No other organic solvents are needed for purification. The purification method is very simple, and the countercurrent flow of the material to be washed and the washing water can effectively save the amount of water used, thereby further reducing the production cost. 3. The entire process steps are very simple, with a high conversion rate, almost 100% conversion, high yield, and product yields of more than 92%; high purity, the product purity reaches 99.9%, the water content is less than 100ppm, and can be directly used as an electrolyte additive, suitable for industrial production.

Claims

1. A method for preparing N,N-dimethyl trifluoromethanesulfonamide, using trifluoromethanesulfonyl fluoride and dimethylamine as reaction raw materials, characterized in that: A dynamic tubular reactor is used, and the two ends of the dynamic tubular reactor are respectively the dynamic tubular reactor input end and the dynamic tubular reactor output end. The dynamic tubular reactor is provided with a stirring screw capable of conveying materials from the dynamic tubular reactor input end to the dynamic tubular reactor output end. The trifluoromethanesulfonyl fluoride and dimethylamine reacting in the dynamic tubular reactor are both in liquid state. The dynamic tubular reactor is divided into a cooling section, a heat preservation section, and a heating section from the dynamic tubular reactor input end to the dynamic tubular reactor output end. The temperature in the dynamic tubular reactor in the cooling section is controlled at -50°C to -30°C, and the temperature in the dynamic tubular reactor in the heating section is controlled at 30°C to 50°C. The mass flow ratio of trifluoromethanesulfonyl fluoride to dimethylamine input is controlled at 1:0.65 to 0.75; the retention time of the reaction material in the dynamic tubular reactor is controlled to be 45min~75min; the material output from the output end of the dynamic tubular reactor enters the centrifugal extraction mechanism for water washing, and the centrifugal extraction mechanism includes at least two stages of centrifugal extractors arranged in series; after washing in each stage of the centrifugal extractors arranged in series, N,N-dimethyl trifluoromethanesulfonamide product is obtained; liquid trifluoromethanesulfonyl fluoride is provided by a liquid trifluoromethanesulfonyl fluoride supply mechanism, and the liquid trifluoromethanesulfonyl fluoride supply mechanism includes: a trifluoromethanesulfonyl fluoride storage tank for storing trifluoromethanesulfonyl fluoride, the trifluoromethanesulfonyl fluoride storage tank is arranged in a cooling device, and the trifluoromethanesulfonyl fluoride in the trifluoromethanesulfonyl fluoride storage tank is in liquid state under the cooling effect of the cooling device, and a first output pipe is arranged in the trifluoromethanesulfonyl fluoride storage tank, and the lower end of the first output pipe extends into the bottom of the trifluoromethanesulfonyl fluoride storage tank, and the upper end of the first output pipe is connected to a trifluoromethanesulfonyl fluoride delivery pipe coated with a heat-insulating material, and the trifluoromethanesulfonyl fluoride is provided in the trifluoromethanesulfonyl fluoride storage tank. The sulfonyl fluoride delivery pipe is connected to the input end of the dynamic tubular reactor, and the trifluoromethanesulfonyl fluoride delivery pipe is provided with a first back pressure valve, a first mass flow meter, and a first check valve in sequence along the delivery direction of the trifluoromethanesulfonyl fluoride; under the action of the liquid trifluoromethanesulfonyl fluoride delivery power mechanism, the liquid trifluoromethanesulfonyl fluoride is delivered to the tubular reactor through the first output pipe and the trifluoromethanesulfonyl fluoride delivery pipe; the liquid dimethylamine is provided by the liquid dimethylamine supply mechanism, and the liquid dimethylamine supply mechanism comprises: a dimethylamine storage tank for storing liquid dimethylamine, the dimethylamine storage tank is arranged in a cooling device, and the dimethylamine is cooled by the cooling device. The dimethylamine in the storage tank is in liquid state. A second output pipe is arranged in the dimethylamine storage tank. The lower end of the second output pipe extends into the bottom of the dimethylamine storage tank. The upper end of the second output pipe is connected to a dimethylamine delivery pipe coated with a heat-insulating material. The dimethylamine delivery pipe is connected to the input end of the dynamic tubular reactor. A second back pressure valve, a second mass flow meter, and a second check valve are arranged on the dimethylamine delivery pipe in sequence along the delivery direction of the liquid dimethylamine. Under the action of the liquid dimethylamine delivery power mechanism, the liquid dimethylamine is delivered to the dynamic tubular reactor through the second output pipe and the dimethylamine delivery pipe. The output end of the dynamic tubular reactor is connected to a receiving valve. The material in the collecting tank is transported to the centrifugal extraction mechanism through a delivery pump; the material in the collecting tank is sequentially washed in each stage of the centrifugal extractor arranged in series, and the washing water is reversely entered into the centrifugal extractors arranged in series in order. The flow direction of the material to be washed in the centrifugal extraction mechanism is opposite to the flow direction of the washing water in the centrifugal extraction mechanism. The washed material is output from the last stage of the centrifugal extraction machine, and the waste water generated by washing is discharged from the first stage of the centrifugal extraction machine; 2 to 6 stages of centrifugal extractors are arranged in series in the centrifugal extraction mechanism; the length ratio of the cooling section, the heat preservation section, and the heating section is 2:4:

4. .

2. A method for preparing N,N-dimethyltrifluoromethanesulfonamide according to claim 1, characterized in that: The pressure of the first back pressure valve is adjusted to 0.2 ~ 0.6 MPa.

3. A method for preparing N,N-dimethyltrifluoromethanesulfonamide according to claim 1, characterized in that: The pressure of the second back pressure valve is adjusted to 0.2 ~ 0.6MPa.

4. A method for preparing N,N-dimethyl trifluoromethanesulfonamide according to claim 1, 2 or 3, characterized in that: The liquid trifluoromethanesulfonyl fluoride conveying power mechanism and the liquid dimethylamine conveying power mechanism comprise: a nitrogen input main pipe, a pressure reducing valve is arranged on the nitrogen input main pipe, the nitrogen input main pipe is connected with a first nitrogen input branch pipe with a first branch pipe check valve and a second nitrogen input branch pipe with a second branch pipe check valve, the first nitrogen input branch pipe extends into a trifluoromethanesulfonyl fluoride storage tank, and the second nitrogen input branch pipe extends into a dimethylamine storage tank; nitrogen enters the trifluoromethanesulfonyl fluoride storage tank through the nitrogen input main pipe and the first nitrogen input branch pipe, so that liquid trifluoromethanesulfonyl fluoride is conveyed to a dynamic tubular reactor through a first output pipe and a trifluoromethanesulfonyl fluoride conveying pipe by means of pressurization; nitrogen enters the dimethylamine storage tank through the nitrogen input main pipe and the second nitrogen input branch pipe, so that liquid dimethylamine is conveyed to the dynamic tubular reactor through a second output pipe and a dimethylamine conveying pipe by means of pressurization.

5. The method for preparing N,N-dimethyltrifluoromethanesulfonamide according to claim 1, characterized in that: The centrifugal extraction mechanism comprises four-stage centrifugal extractors arranged in series, and the volume flow ratio of the material to be washed to the deionized water is 1: (0.3 ~ 0.5).

6. The method for preparing N,N-dimethyltrifluoromethanesulfonamide according to claim 1, characterized in that: The dynamic tubular reactor of the cooling section is provided with a cooling jacket, a refrigerant with a temperature of -50°C to -30°C is passed into the cooling jacket, an inlet of the cooling jacket is arranged close to the insulation section, and an outlet of the cooling jacket is arranged close to the inlet end of the dynamic tubular reactor; an insulation layer is arranged on the outer wall of the dynamic tubular reactor of the insulation section; a heating jacket is provided on the dynamic tubular reactor of the heating section, water with a temperature of 30°C to 50°C is passed into the heating jacket, an inlet of the heating jacket is arranged close to the outlet end of the dynamic tubular reactor, and an outlet of the heating jacket is arranged close to the insulation section.

7. The method for preparing N,N-dimethyltrifluoromethanesulfonamide according to claim 1, characterized in that: The speed of the stirring screw is controlled at 80 ~ 120 rpm.

8. The method for preparing N,N-dimethyltrifluoromethanesulfonamide according to claim 1, characterized in that: The pressure in the dynamic tubular reactor is controlled at 0.4 MPa ~ 0.6 MPa.

9. The method for preparing N,N-dimethyltrifluoromethanesulfonamide according to claim 1, characterized in that: The water used for washing is deionized water.

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