Preparation method of methylsulfonyl fluoride

Abstract

The invention relates to the technical field of fine chemical engineering, in particular to a preparation method of methylsulfonyl fluoride, which comprises the following steps: sequentially adding methylsulfonyl chloride, metal fluoride and a dispersing agent into a reactor according to the molar ratio of (1.2-1.5): 1, stirring, fully dispersing the materials, raising the temperature of a reaction system to 70-100 DEG C, and reacting for 1-2 hours; and carrying out heat preservation reaction for 8-10 hours, and carrying out vacuum suction filtration on the obtained material to obtain the methylsulfonyl fluoride. The method has the beneficial effects that the methanesulfonyl chloride is taken as a raw material, the methanesulfonyl chloride can directly react with the metal fluoride at a relatively high temperature without dissolving the metal fluoride by a solvent, meanwhile, the dispersing agent is added to adjust the viscosity of the system, the reaction process can be effectively controlled, and the reaction time is shortened. And the problem that local response is too fast is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of fine chemicals, and in particular to a method for preparing methylsulfonyl fluoride. Background Art

[0002] Trifluoromethanesulfonic acid is an organic superacid, widely used in the fields of medicine, chemical industry, materials, electronics, electroplating, etc. It is also one of the main raw materials for the preparation of lithium trifluoromethanesulfonate and lithium bis(trifluoromethanesulfonyl)imide, which are important raw materials for lithium battery electrolyte.

[0003] Trifluoromethanesulfonic acid is generally prepared by electrofluorination of methylsulfonyl fluoride, acidification with inorganic acid and other processes. Methylsulfonyl fluoride is the main raw material for preparing trifluoromethanesulfonic acid. At present, the main preparation method of methylsulfonyl fluoride is to hydrolyze and fluorinate methylsulfonyl chloride in an aqueous solution of a fluorinating agent such as potassium fluoride and sodium fluoride, such as the following process disclosed in the patent application with publication number CN101747237A:

[0004]

[0005] The hydrolysis fluorination method has the advantages of simple process and fast reaction speed, but due to the hydrolysis side reaction of acyl chloride and acyl fluoride, the reaction yield is low, generally less than 90%. In addition, the separation wastewater discharged also causes environmental pollution problems. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a method for preparing anhydrous methylsulfonyl fluoride with high reaction yield.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: to provide a method for preparing methylsulfonyl fluoride, comprising the following steps: adding methylsulfonyl chloride, metal fluoride and dispersant into a reactor in sequence, and after sufficient reaction, separating the reaction product from the metal fluoride to obtain methylsulfonyl fluoride.

[0008] Furthermore, in the above-mentioned method for preparing methylsulfonyl fluoride, the dispersant is an anhydrous liquid component, and its water content is ≤500ppm.

[0009] Furthermore, in the above-mentioned method for preparing methylsulfonyl fluoride, the dispersant is methylsulfonyl fluoride.

[0010] Furthermore, in the above-mentioned method for preparing methylsulfonyl fluoride, the reaction is a continuous flow reaction, the methylsulfonyl chloride and methylsulfonyl fluoride are fed into the reactor in a continuous flow form for reaction, and the reaction product is separated from the metal fluoride in a continuous flow form.

[0011] Furthermore, in the above-mentioned method for preparing methylsulfonyl fluoride, the reactor is a fixed bed, and the metal fluoride is loaded in the fixed bed.

[0012] Furthermore, in the above-mentioned method for preparing methylsulfonyl fluoride, the temperature range of the reactor is 70-100°C.

[0013] Furthermore, in the above-mentioned method for preparing methylsulfonyl fluoride, the mass ratio of methylsulfonyl fluoride to methylsulfonyl chloride is 0.8 to 1:1.

[0014] Furthermore, in the above-mentioned method for preparing methylsulfonyl fluoride, the molar ratio of methylsulfonyl chloride to metal fluoride is 1.2-1.5:1.

[0015] Furthermore, in the above-mentioned method for preparing methylsulfonyl fluoride, the metal fluoride is potassium fluoride, sodium fluoride or cesium fluoride.

[0016] Furthermore, in the above-mentioned method for preparing methylsulfonyl fluoride, the water content of the methylsulfonyl chloride is ≤500ppm. Furthermore, in the above-mentioned method for preparing methylsulfonyl fluoride, the dispersant is methylsulfonyl fluoride.

[0017] The beneficial effects of the present invention are as follows: the present invention provides a method for preparing methylsulfonyl fluoride, wherein methylsulfonyl chloride is used as a raw material, and methylsulfonyl chloride reacts directly with metal fluoride at a relatively high temperature without the need for a solvent to dissolve the metal fluoride, and a dispersant is added to adjust the viscosity of the system to avoid excessive concentration of reactants, thereby causing problems such as system viscosity, uneven reaction degree, and violent local reaction. The method of the present invention has the following advantages: 1. The three wastes of the reaction are greatly reduced. The method is an anhydrous reaction and does not generate wastewater. When methylsulfonyl fluoride is selected as the dispersant, the dispersant itself is the product, which avoids the product separation problem involved in the traditional method and improves the production efficiency. The dispersant can also be reused, which improves the environmental benefits and reduces the production cost. 2. The problem of the existence of acyl chloride and acyl fluoride hydrolysis side reactions in the traditional hydrolysis fluorination reaction is solved. 3. Under anhydrous conditions, the reaction activity of metal fluorides is high, which can improve the reaction efficiency and the utilization rate of raw materials. The conversion rate of the raw material methylsulfonyl chloride can reach more than 99.7%. 4. Different from the traditional homogeneous reaction, the method is a solid-liquid reaction, which is convenient for introducing fixed bed and other reaction equipment for continuous production and is suitable for the industrial preparation of methylsulfonyl fluoride. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The GC (gas chromatography) spectrum of the trimethylsulfonyl fluoride product of the embodiment of the present invention in a specific embodiment is shown. DETAILED DESCRIPTION

[0019] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in combination with the implementation modes and the accompanying drawings.

[0020] The key concept of the present invention is that the present invention proposes a new method for preparing methylsulfonyl fluoride without water. The prior art generally believes that methylsulfonyl fluoride is obtained by mixing a metal fluoride, such as potassium fluoride (KF), with methylsulfonyl chloride, and then reacting in the presence of a solvent, such as water. JP1993005524 also believes that the undissolved part of the metal fluoride does not react with methylsulfonyl chloride, and proposes to increase the amount of water added to the reaction system so as to complete the reaction between the metal fluoride and methylsulfonyl chloride in a short time. However, the inventors have found that at a higher temperature, methylsulfonyl chloride can react directly with the metal fluoride without the need for a solvent to dissolve the metal fluoride, and that the simultaneous addition of methylsulfonyl fluoride can effectively control the reaction process and avoid problems such as excessive local reaction.

[0021] The system of the present application is anhydrous and does not have the problem of hydrolysis. Anhydrous methyl sulfonyl fluoride can be added as a dispersant. Because the reactant methyl sulfonyl chloride is liquid and anhydrous potassium fluoride is solid powder, the reaction system cannot be fully dispersed and appears viscous, resulting in a rapid termination of the reaction. Methyl sulfonyl fluoride is added, on the one hand, as a dispersant to adjust the viscosity of the system, and on the other hand, it is also a product itself and does not need to be separated after the reaction.

[0022] Embodiment 1

[0023] 300 g of methylsulfonyl chloride (water content 280 ppm) and 182.6 g of anhydrous potassium fluoride were added to a 1L three-necked flask. After completion, 240 g of anhydrous methylsulfonyl fluoride was added to the flask. Stirring was started, and the speed was gradually adjusted to 400 rpm. After the materials were fully dispersed, the temperature was increased to 70 ° C and the reaction was kept warm for 8 hours. After the reaction was completed, the materials were vacuum filtered to obtain methylsulfonyl fluoride product 1. The reaction conversion rate was 99.7%.

[0024] Embodiment 2

[0025] 300 g of methylsulfonyl chloride (water content 280 ppm) and 228.2 g of anhydrous potassium fluoride were added to a 1L three-necked flask. After completion, 300 g of anhydrous methylsulfonyl fluoride was added to the flask. Stirring was started, and the speed was gradually adjusted to 400 rpm. After the materials were fully dispersed, the temperature was increased to 100 ° C, and the reaction was kept warm for 10 hours. After the reaction was completed, the materials were vacuum filtered to obtain methylsulfonyl fluoride product 2. The reaction conversion rate was 99.9%.

[0026] Embodiment 3

[0027] Add 300g of methylsulfonyl chloride (water content 280ppm) and 228.2g of anhydrous potassium fluoride into a 1L three-necked flask. After completion, add 240g of anhydrous methylsulfonyl fluoride into the flask. Start stirring, gradually adjust the speed to 400rpm, and after the materials are fully dispersed, start heating, raise the temperature of the reaction system to 100℃, and keep the temperature for 10 hours. After the reaction is completed, vacuum filter the material to obtain methylsulfonyl fluoride product 3. The reaction conversion rate is 100%. Please refer to Figure 1 , which is the GC spectrum of the methylsulfonyl fluoride product obtained in this example.

[0028] Embodiment 4

[0029] 300 g of methylsulfonyl chloride (water content 280 ppm) and 228.2 g of anhydrous potassium fluoride were added to a 1L three-necked flask. After completion, 300 g of anhydrous methylsulfonyl fluoride was added to the flask. Stirring was started, and the speed was gradually adjusted to 400 rpm. After the materials were fully dispersed, the temperature was increased to 100 ° C, and the reaction was kept warm for 8 hours. After the reaction was completed, the materials were vacuum filtered to obtain methylsulfonyl fluoride product 4. The reaction conversion rate was 99.9%.

[0030] Embodiment 5

[0031] 300 g of methylsulfonyl chloride (water content 280 ppm) and 205.4 g of anhydrous potassium fluoride were added to a 1L three-necked flask. After completion, 260 g of anhydrous methylsulfonyl fluoride was added to the flask. Stirring was started, and the speed was gradually adjusted to 400 rpm. After the materials were fully dispersed, the temperature was increased to 100 ° C, and the reaction was kept warm for 10 hours. After the reaction was completed, the materials were vacuum filtered to obtain methylsulfonyl fluoride product 5. The reaction conversion rate was 99.8%.

[0032] Embodiment 6

[0033] 300 g of methylsulfonyl chloride (water content 280 ppm) and 213 g of anhydrous potassium fluoride were added to a 1L three-necked flask. After completion, 270 g of anhydrous methylsulfonyl fluoride was added to the flask. Stirring was started, and the speed was gradually adjusted to 400 rpm. After the materials were fully dispersed, the temperature was raised to 90 ° C and the reaction was kept warm for 8 hours. After the reaction was completed, the materials were vacuum filtered to obtain methylsulfonyl fluoride product 6. The reaction conversion rate was 99.9%.

[0034] Embodiment 7

[0035] 300 g of methylsulfonyl chloride (water content 280 ppm) and 213 g of anhydrous potassium fluoride were added to a 1L three-necked flask. After completion, 270 g of anhydrous methylsulfonyl fluoride was added to the flask. Stirring was started, and the speed was gradually adjusted to 400 rpm. After the materials were fully dispersed, the temperature was increased to 100 ° C, and the reaction was kept warm for 10 hours. After the reaction was completed, the materials were vacuum filtered to obtain methylsulfonyl fluoride product 7. The reaction conversion rate was 100%.

[0036] The experimental conditions in each embodiment are summarized in Table 1.

[0037] Table 1

[0038]

[0039] Comparative Example 1

[0040] 300 g of methylsulfonyl chloride (water content 280 ppm) and 213 g of anhydrous potassium fluoride were added to a 1L three-necked flask. Stirring was started, the speed was gradually adjusted to 400 rpm, and the temperature of the reaction system was raised to 100 ° C. The reaction was kept warm for 8 hours. After the reaction was completed, the system was viscous, the reaction system could not be fully dispersed, the product separation was difficult, and the conversion rate was ~60%.

[0041] The above embodiment of the present invention adopts an anhydrous system to carry out the fluorination process of methanesulfonyl chloride. In this scheme, the activity of fluorinating agents such as potassium fluoride is relatively high, so the reaction can be carried out based on a fixed bed reactor to achieve continuous synthesis of methanesulfonyl fluoride. The specific steps include:

[0042] A fixed bed continuous flow reactor is used, in which anhydrous potassium fluoride (KF) is fixed on a suitable carrier to form a reaction catalytic unit. The reaction catalytic unit can be movably fixed in the reaction device, and a spare reaction catalytic unit is also provided in the reaction device. When the potassium fluoride of the original reaction catalytic unit is lost, it can be directly replaced without stopping the machine. A raw material tank and a product receiving tank are set in the reaction device, and a precise feed pump can be equipped to continuously and constantly deliver methylsulfonyl chloride and methylsulfonyl fluoride. An online sensor can be used to monitor the temperature, pressure and material concentration in the reactor in real time, and the flow rate of the feed pump can be adjusted according to the feedback signal to maintain the stability of the reaction conditions.

[0043] During the reaction, methyl sulfonyl chloride and methyl sulfonyl fluoride are mixed and continuously fed into a fixed bed reactor, and a fluorination reaction occurs after being catalyzed by potassium fluoride to obtain the product methyl sulfonyl fluoride. The reactor temperature range is set at 70 to 100°C, and the mass ratio of methyl sulfonyl fluoride to methyl sulfonyl chloride is 0.8 to 1:1. After the reaction, the continuously separated products are collected.

[0044] In summary, in the preparation method of methyl sulfonyl fluoride of the present application, methyl sulfonyl chloride and anhydrous potassium fluoride are reacted to generate methyl sulfonyl fluoride. Under anhydrous conditions, since no hydrolysis process occurs, the reaction conversion rate is close to complete conversion, while in the prior art, a hydrolysis side reaction will occur in the water system, and the yield is generally about 90%; at the same time, by adding a dispersant, the problem of viscosity of the reaction system under anhydrous conditions is solved; preferably, methyl sulfonyl fluoride is added to the system, which can directly simplify the separation process after the reaction. According to Examples 1-7 and Comparative Example 1, m 酰氟 :m 酰氯 =(0.8~1):1 is the preferred dispersant mass range, when m 酰氟 :m 酰氯 =(0-0.8:1), the viscosity of the system gradually decreases, and when it reaches 0.8:1, the product can be easily separated while ensuring the reaction efficiency.

[0045] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing methylsulfonyl fluoride, characterized in that: The method comprises the following steps: sequentially adding methylsulfonyl chloride, metal fluoride and dispersant into a reactor, and after sufficient reaction, separating the reaction product from the metal fluoride to obtain methylsulfonyl fluoride.

2. The method for preparing methylsulfonyl fluoride according to claim 1, characterized in that: The dispersant is an anhydrous liquid component, and its water content is ≤500ppm.

3. The method for preparing methylsulfonyl fluoride according to claim 2, characterized in that: The dispersant is methylsulfonyl fluoride.

4. The method for preparing methylsulfonyl fluoride according to claim 3, characterized in that: The reaction is a continuous flow reaction, the methylsulfonyl chloride and methylsulfonyl fluoride are fed into the reactor in a continuous flow form for reaction, and the reaction product is separated from the metal fluoride in a continuous flow form.

5. The method for preparing methylsulfonyl fluoride according to claim 4, characterized in that: The reactor is a fixed bed, and the metal fluoride is loaded in the fixed bed.

6. The method for preparing methylsulfonyl fluoride by continuous reaction according to claim 1, characterized in that: The temperature range of the reactor is 70-100°C.

7. The method for preparing methylsulfonyl fluoride by continuous reaction according to claim 3, characterized in that: The mass ratio of the methylsulfonyl fluoride to the methylsulfonyl chloride is 0.8 to 1:

1.

8. The method for preparing methylsulfonyl fluoride by continuous reaction according to claim 1, characterized in that: The molar ratio of the methanesulfonyl chloride to the metal fluoride is 1.2-1.5:

1.

9. The method for preparing methylsulfonyl fluoride by continuous reaction according to claim 1, characterized in that: The metal fluoride is potassium fluoride, sodium fluoride or cesium fluoride.

10. The method for preparing methylsulfonyl fluoride by continuous reaction according to claim 1, characterized in that: The water content of the methanesulfonyl chloride is ≤500ppm.

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