A method for preparing a bischlorosulfonimide acid

Abstract

The present application relates to a kind of preparation method of bischlorosulfonimide acid, belong to new energy battery electrolyte salt technical field.The preparation method of bischlorosulfonimide acid disclosed in the present application includes the following steps: first, amino sulfuryl chloride, sulfur trioxide are used as raw material to synthesize monohydroxy sulfuryl imide acid intermediate.Then, with monohydroxy sulfuryl imide acid as raw material, bischlorosulfonimide acid is generated in the reaction of thionyl chloride.Finally, bischlorosulfonimide acid is purified by the method of melt crystallization, and high-quality bischlorosulfonimide acid product is obtained.The present application has the advantages of high atom utilization rate, less waste gas, high product purity, meets the demand of electrolyte industry for high-quality bischlorosulfonimide acid, and is suitable for industrial production.

Description

Technical Field

[0001] This invention belongs to the field of chemical engineering, and specifically relates to a method for preparing dichlorosulfonylimine. Background Technology

[0002] Dichlorosulfonyl imine (HN(SO2Cl)2) is an important precursor for the synthesis of lithium bisfluorosulfonylimide (LiFSI), a lithium salt used in lithium-ion batteries, and has important applications in lithium-ion batteries, ionic liquids, and catalytic materials.

[0003] Currently, existing preparation technologies both domestically and internationally suffer from problems such as complex product composition, difficulty in separating impurities entrained in the product, large waste gas generation, high equipment requirements, and difficulty in large-scale production. Most current patents employ a one-pot synthesis method for dichlorosulfonyl imide acid (R. Appeletal, Chem. Ber. 1962, 95, 625; R. Appeleta, Chem. Ber. 1962, 95, 1753; EA Fadia, US4315935, 1982; M. Beran et al, Z. Anorg. Allg. Chem. 2005, 631, 55), which involves reacting chlorosulfonic acid, aminosulfonic acid, and thionyl chloride in a single pot. The advantages of this method are high reaction conversion rate and relatively simple process conditions. The disadvantages are: 1. The reaction produces large amounts of sulfur dioxide and hydrogen chloride gas, which are difficult to completely separate from the product, increasing environmental costs during manufacturing. From an atom economy perspective, the element utilization rate is relatively low, making it uneconomical. 2. The reaction raw materials and products remain in the reaction system for too long, leading to side reactions between the products and raw materials. Impurities generated by these side reactions are difficult to separate from the system, affecting product quality. 3. After the reaction, the product needs to be distilled off using high-temperature, vacuum distillation. Dichlorosulfonyl acid and the generated HCl gas are highly corrosive to equipment, placing extremely high demands on the equipment and making large-scale production problematic.

[0004] Patent WO2009123328A1 uses cyanide gas and sulfur trioxide to prepare chlorosulfonic acid isocyanate, which is then reacted with chlorosulfonic acid to prepare dichlorosulfonylimine. This route uses the highly toxic gas cyanide, making it difficult to scale up for production.

[0005] In summary, the currently disclosed methods for synthesizing bis(chlorosulfonyl)imide acid suffer from problems such as low atom utilization, high raw material consumption, large waste gas generation, difficulty in product purification, and difficulty in industrial scale-up. Developing an energy-saving, environmentally friendly, and easily purified method for synthesizing bis(chlorosulfonyl)imide will promote the large-scale application of bis(chlorosulfonyl)imide and its alkali metal salts, making it a mainstream electrolyte material in new energy devices such as lithium-ion batteries and supercapacitors. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing dichlorosulfonylimine acid, which solves the problems of low atom utilization, high raw material consumption, large waste gas generation, difficult product purification, and difficulty in industrial scale-up in the prior art.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A method for preparing a dichlorosulfonylimine acid includes the following steps:

[0009] 1) First, aminosulfonyl chloride and sulfur trioxide are added to organic solvent a in a molar ratio. Under the action of an initiator, the mixture is stirred at 30-90°C for 2-6 hours. The mixture is then separated and dried to obtain a white powder of monohydroxysulfonylimine.

[0010]

[0011] 2) Add the monohydroxysulfonylimine acid and thionyl chloride obtained in step 1) to organic solvent b in a certain molar ratio, and stir the reaction at 30-110℃ for 4-8 hours to obtain the reaction solution;

[0012]

[0013] 3) Cool the reaction solution obtained in step 2) to crystallize, so that dichlorosulfonimide acid precipitates out in crystal form. Remove excess organic solvent b by nitrogen pressure filtration. The remaining solid is first heated to melt and then cooled to crystallize. Repeat the operation 3 to 5 times to finally obtain dichlorosulfonimide acid.

[0014] Step 2) After the reaction is completed, sulfur dioxide and HCl in the reaction tail gas are separated by physical separation. The separated sulfur dioxide can be recycled as a raw material for thionyl chloride.

[0015] In step 1), the aminosulfonyl chloride and sulfur trioxide are in a molar ratio of 1:(1.02-1.05).

[0016] In step 1), organic solvent a is an aprotic solvent;

[0017] Preferably, organic solvent a is one or a mixture of several of acetonitrile, toluene, dichloromethane, dichloroethane, chlorobenzene, o-dichlorobenzene, and tetrahydrofuran;

[0018] In step 1), the initiator is one of hydrogen chloride, hydroiodic acid, hydrobromic acid, and hydrofluoric acid.

[0019] As a further preferred embodiment of the present invention, the separation method during the synthesis of the monohydroxysulfonylimine intermediate is one of vacuum filtration, pressure filtration and centrifugation.

[0020] As a further preferred embodiment of the present invention, the drying method used in the synthesis of the monohydroxysulfonylimine intermediate is one of rotary drying, oven drying, and airflow drying.

[0021] In step 2), the molar ratio of monohydroxysulfonylimide acid to thionyl chloride is 1:(2.5-5.5).

[0022] In step 2), organic solvent b is an aprotic solvent;

[0023] Preferably, the organic solvent b is selected from one or a mixture of several of thionyl chloride, dichloromethane, toluene, and o-dichlorobenzene.

[0024] As a further preferred embodiment of the present invention, the organic solvent used in the synthesis of dichlorosulfonylimide acid is an aprotic solvent, and the organic solvent used in the synthesis of monohydroxysulfonylimide acid intermediate can be the same or different.

[0025] In step 3), the melting temperature during the purification of dichlorosulfonylimide acid by the melt crystallization method is 30-45°C.

[0026] In step 3), the cooling crystallization temperature during the purification of dichlorosulfonylimide acid by melt crystallization is between -10°C and 0°C.

[0027] This technology yields high-quality dichlorosulfonylimide acid products. The invention offers advantages such as high atom utilization, low waste gas emissions, and high product purity, meeting the electrolyte industry's demand for high-quality dichlorosulfonylimide acid and is suitable for industrial production.

[0028]

[0029] The traditional chlorosulfonic acid process produces 3 molecules of hydrochloric acid and 2 molecules of chlorine dioxide, while our process only uses 1 molecule of thionyl chloride to produce 1 molecule of hydrochloric acid and 1 molecule of sulfur dioxide.

[0030] Beneficial effects of the present invention

[0031] This invention proposes a method for preparing dichlorosulfonylimine. Compared with existing technologies, this process generates only sulfur dioxide and HCl with a molecular weight of one, resulting in high element utilization. Furthermore, sulfur dioxide and HCl can be separated, and the separated sulfur dioxide can be recycled as a raw material for the synthesis of thionyl chloride, making the process more environmentally friendly. By separating the reaction intermediates from the system, the further reaction between raw materials and products to form polymers is avoided, eliminating the generation of side reaction impurities and ensuring high product purity. The product is purified through melt crystallization, which is more energy-efficient and safer than traditional high-temperature, vacuum distillation methods. It also has lower equipment requirements, making it suitable for large-scale industrial production. Detailed Implementation

[0032] This invention discloses a method for preparing dichlorosulfonylimide acid, comprising the following steps: 1. First, aminosulfonyl chloride and sulfur trioxide are added to an organic solvent in a certain molar ratio. Under the action of an initiator, a monohydroxysulfonylimide acid intermediate is obtained. The intermediate is then separated and dried to obtain a white powder of monohydroxysulfonylimide acid. 2. The above monohydroxysulfonylimide acid and thionyl chloride are added to an organic solvent in a certain molar ratio. The mixture is stirred and reacted at a certain temperature to obtain dichlorosulfonylimide acid. 3. The above reaction solution is purified by melt crystallization. The polymerization process involves first cooling and crystallizing the reaction solution to precipitate dichlorosulfonylimide acid in crystalline form. Excess organic solvent is removed by nitrogen pressure filtration. The remaining chlorosulfonylimide acid crystals are then subjected to a melt crystallization process involving heating and cooling to obtain a high-purity dichlorosulfonylimide acid product.

[0033] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0034] A method for preparing difluorosulfonylimine acid includes the following steps:

[0035] Aminosulfonyl chloride and sulfur trioxide were used as raw materials and added to an organic solvent at a molar ratio of 1:(1.02-1.05). The mixture was stirred at 30-90°C for 2-6 hours under the action of an initiator to obtain a monohydroxysulfonylimide intermediate. The monohydroxysulfonylimide was then separated and dried to obtain a white powder.

[0036] The monohydroxysulfonylimide acid white solid obtained above and thionyl chloride were added to an organic solvent at a molar ratio of 1:(2.5-5.5), and the mixture was stirred at 30-110°C for 4-8 hours to obtain dichlorosulfonylimide acid.

[0037] The above reaction solution is first cooled to the range of -10 to 0℃ to allow dichlorosulfonamide acid to precipitate in the form of crystals. Excess organic solvent is discharged by nitrogen pressure filtration. The remaining solid is then repeatedly subjected to melting and crystallization operations of heating and cooling in the range of 30 to 45℃ to finally obtain a high-purity dichlorosulfonamide acid product.

[0038] The technical solution of the present invention will now be described in detail through specific embodiments.

[0039] Example 1

[0040] 57.8 g of aminosulfonyl chloride (0.5 mol) and 212.3 g of dichloromethane (2.5 mol) were added to a three-necked reaction flask. The flask was connected to a condenser, a bubbler, and a tail gas absorption device, and magnetic stirring was turned on. 40.8 g of sulfur trioxide (0.51 mol) was added to the reaction flask, and then HCl gas was introduced into the reaction flask until bubbles began to emerge from the bubbler. After the addition was complete, the temperature was raised to 35°C. As the reaction proceeded, a white solid began to precipitate. After stirring for 5 hours, a sample was taken, and liquid chromatography analysis showed that no aminosulfonyl chloride remained, which was the endpoint of the reaction. The reaction solution was separated by vacuum filtration and dried by rotary evaporation to obtain 97.35 g of monohydroxysulfonylimine acid white solid powder.

[0041] 88.00 g of monohydroxysulfonylimide acid (0.45 mol) and 107.1 g of thionyl chloride (0.90 mol) were added to 191.1 g of dichloromethane (2.25 mol), and the mixture was stirred at 35 °C for 6 h to obtain dichlorosulfonylimide acid.

[0042] The reaction solution was cooled to -10°C, causing dichlorosulfonylimide acid to precipitate as crystals. The solvent was removed by nitrogen pressure filtration. The remaining crystals in the reaction flask were heated to 40°C until all the crystals dissolved. Then, the temperature was lowered to 30°C, and the dissolved crystals recrystallized. The liquid was removed by nitrogen pressure filtration. This process of heating and melting followed by cooling and crystallization was repeated three times to obtain 95.48 g of dichlorosulfonylimide acid product.

[0043] Example 2

[0044] 57.8 g of aminosulfonyl chloride (0.5 mol) and 191.1 g of dichloromethane (2.25 mol) were added to a three-necked reaction flask. The flask was connected to a condenser, a bubbler, and a tail gas absorption device, and magnetic stirring was turned on. 41.2 g of sulfur trioxide (0.52 mol) was added to the reaction flask, and then HCl gas was introduced into the reaction flask until bubbles began to emerge from the bubbler. After the addition was complete, the temperature was raised to 35°C. As the reaction proceeded, a white solid began to precipitate. After stirring for 5 hours, a sample was taken, and liquid chromatography analysis showed that no aminosulfonyl chloride remained, which was the endpoint of the reaction. The reaction solution was separated by vacuum filtration and dried by rotary evaporation to obtain 97.6 g of monohydroxysulfonylimine acid white solid powder.

[0045] 88.00 g of monohydroxysulfonylimide acid (0.45 mol) and 133.8 g of thionyl chloride (1.13 mol) were added to 172.0 g of dichloromethane (2.03 mol), and the mixture was stirred at 35 °C for 6 h to obtain dichlorosulfonylimide acid.

[0046] The reaction solution was cooled to -5°C, causing dichlorosulfonylimide acid to precipitate as crystals. The solvent was removed by nitrogen pressure filtration. The remaining crystals in the reaction flask were heated to 35°C until all the crystals dissolved. The mixture was then cooled to 30°C, and the dissolved crystals recrystallized. The liquid was removed by nitrogen pressure filtration. This process of heating and melting followed by cooling and crystallization was repeated four times to obtain 95.83 g of dichlorosulfonylimide acid product.

[0047] Example 3

[0048] 57.8 g of aminosulfonyl chloride (0.5 mol) and 367.5 g of o-dichlorobenzene (2.50 mol) were added to a 500 ml three-necked reaction flask. The flask was connected to a condenser, a bubbler, and a tail gas absorption device, and magnetic stirring was turned on. 42.0 g of sulfur trioxide (0.53 mol) was added to the reaction flask, and then HBr gas was bubbled into the reaction flask until bubbles began to emerge from the bubbler. After the addition was complete, the temperature was raised to 65 °C. As the reaction proceeded, a white solid began to precipitate. After stirring for 5 hours, a sample was taken, and liquid chromatography analysis showed that no aminosulfonyl chloride remained, which was the endpoint of the reaction. The reaction solution was separated by vacuum filtration and dried by rotary evaporation to obtain 96.9 g of monohydroxysulfonylimine acid white solid powder.

[0049] 88.00 g of monohydroxysulfonylimide acid (0.45 mol) and 267.7 g of thionyl chloride (2.25 mol) were added to a reaction flask and stirred at 65 °C for 6 h to obtain dichlorosulfonylimide acid.

[0050] The reaction solution was cooled to 0°C, and dichlorosulfonylimide acid precipitated as crystals. The solvent was removed by nitrogen pressure filtration. The remaining crystals in the reaction flask were heated to 40°C until all the crystals dissolved. Then, the temperature was lowered to 35°C, and the dissolved crystals recrystallized. The liquid was removed by nitrogen pressure filtration. This process of heating and melting followed by cooling and crystallization was repeated five times to obtain 96.02 g of dichlorosulfonylimide acid product.

[0051] Example 4

[0052] 57.8 g of aminosulfonyl chloride (0.5 mol) and 367.5 g of o-dichlorobenzene (2.50 mol) were added to a 500 ml three-necked reaction flask. The flask was connected to a condenser, a bubbler, and a tail gas absorption device, and magnetic stirring was turned on. 40.8 g of sulfur trioxide (0.51 mol) was added to the reaction flask, and then HCl gas was introduced into the reaction flask until bubbles began to emerge from the bubbler. After the addition was complete, the temperature was raised to 55 °C. As the reaction proceeded, a white solid began to precipitate. After stirring for 5 hours, a sample was taken, and liquid chromatography analysis showed that no aminosulfonyl chloride remained, which was the endpoint of the reaction. The reaction solution was separated by vacuum filtration and dried by rotary evaporation to obtain 96.9 g of monohydroxysulfonylimine acid white solid powder.

[0053] 88.00 g of monohydroxysulfonylimide acid (0.45 mol) and 133.8 g of thionyl chloride (1.13 mol) were added to a reaction flask, followed by 330.8 g of o-dichlorobenzene (2.25). The mixture was stirred at 110 °C for 4 h to obtain dichlorosulfonylimide acid.

[0054] The reaction solution was cooled to -5°C, causing dichlorosulfonylimide acid to precipitate as crystals. The solvent was removed by nitrogen pressure filtration. The remaining crystals in the reaction flask were heated to 40°C until all the crystals dissolved. The solution was then cooled to 35°C, and the dissolved crystals recrystallized. The liquid was removed by nitrogen pressure filtration. This process of heating and melting followed by cooling and crystallization was repeated three times to obtain 95.49 g of dichlorosulfonylimide acid product.

[0055] Example 5

[0056] 57.8 g of aminosulfonyl chloride (0.5 mol) and 184.3 g of toluene (2.00 mol) were added to a 500 ml three-necked reaction flask. The flask was connected to a condenser, a bubbler, and a tail gas absorption device, and magnetic stirring was turned on. 40.8 g of sulfur trioxide (0.51 mol) was added to the reaction flask, and then HCl gas was introduced into the reaction flask until bubbles began to emerge from the bubbler. After the addition was complete, the temperature was raised to 70 °C. As the reaction proceeded, a white solid began to precipitate. After stirring for 6 hours, a sample was taken, and liquid chromatography analysis showed that no aminosulfonyl chloride remained, which was the endpoint of the reaction. The reaction solution was separated by vacuum filtration and dried by rotary evaporation to obtain 97.2 g of monohydroxysulfonylimine acid white solid powder.

[0057] 88.00 g of monohydroxysulfonylimide acid (0.45 mol) and 160.6 g of thionyl chloride (1.35 mol) were added to a reaction flask, followed by 165.9 g of toluene (1.8 g). The mixture was stirred at 100 °C for 5 h to obtain dichlorosulfonylimide acid.

[0058] The reaction solution was cooled to -5°C, causing dichlorosulfonylimide acid to precipitate as crystals. The solvent was removed by nitrogen pressure filtration. The remaining crystals in the reaction flask were heated to 40°C until all the crystals dissolved. The mixture was then cooled to 30°C, and the dissolved crystals recrystallized. The liquid was removed by nitrogen pressure filtration. This process of heating and melting followed by cooling and crystallization was repeated four times to obtain 95.84 g of dichlorosulfonylimide acid product.

[0059] Method for determining the purity of dichlorosulfonylimine:

[0060] 1. Methodology Summary

[0061] Dichlorosulfonylimide acid and chlorosulfonic acid were derivatized with aniline, and the derivatives were separated by C18 reversed-phase chromatography. The differences between the various dichlorosulfonylimide acids were qualitatively determined using a UV detector (230 nm), and the purity of the dichlorosulfonylimide acid was determined by the area normalization method.

[0062] 2. Reagents

[0063] 2.1 Methanol: chromatographic grade.

[0064] 2.2 Phosphoric acid: chromatographic grade.

[0065] 2.3 Aniline: Analytical grade.

[0066] 2.4 Dichloromethane: Analytical grade. (Or 1,2-dichloroethane)

[0067] 2,5-Chlorosulfonic acid: analytical grade.

[0068] 3. Instruments

[0069] 3.1 High-performance liquid chromatograph: equipped with a UV detector or diode array detector. 3.2 Analytical balance: sensitivity 0.1 mg.

[0070] 3.3 Organic filter head: 0.45μm or 0.22μm.

[0071] 4. Chromatographic analysis conditions

[0072] Table 1 Chromatographic analysis conditions

[0073]

[0074] Gradient elution program

[0075]

[0076] 5. Analysis Steps

[0077] 5.1 Solution Preparation

[0078] ① Preparation of 0.2 mol / L aniline dichloromethane solution: Weigh 4.657 g of aniline and place it in a 250 mL volumetric flask.

[0079] Dissolve in dichloromethane, dilute to the mark, and shake well.

[0080] ② Derivatization of chlorosulfonic acid: Take a 50 mL volumetric flask, transfer 10 mL of aniline solution, and add 1 drop of chlorosulfonic acid. Then sonicate at 30 °C for 15 min, cool, and dilute to the mark with a solvent (methanol: 0.1% phosphoric acid water = 7:3).

[0081] ③ Derivatization of dichlorosulfonylimide: Take a 50 mL volumetric flask, transfer 10 mL of aniline solution, and add 1 drop of dichlorosulfonylimide. Then sonicate at 30 °C for 15 min, cool, and dilute to the mark with a solvent (methanol: 0.1% phosphoric acid water = 7:3).

[0082] Note: The weighing quantities of the standard and the sample can be adjusted simultaneously depending on the instrument.

[0083] 5.2 Determination Method

[0084] 5.3 After the instrument has been powered on and warmed up, inject the standard solution and sample solution into the liquid chromatograph in sequence. After the last component has eluted (see Chromatographic Condition 1), process the results using the workstation.

[0085] 5.4 Results

[0086] Example 1 99.84％ Example 2 99.92％ Example 3 99.89％ Example 4 99.74％ Example 5 99.79％

Claims

1. A method for preparing dichlorosulfonylimine, characterized in that, Includes the following steps: 1) Add aminosulfonyl chloride and sulfur trioxide to an organic solvent in a molar ratio, and stir the reaction at 30~90℃ for 2~6h under the action of an initiator. The white powder of monohydroxysulfonylimine is obtained by separation and drying. 2) Add the monohydroxysulfonylimine acid and thionyl chloride obtained in step 1) into an organic solvent at a certain molar ratio, and stir the reaction at 30~110℃ for 4~8h to obtain a reaction solution; 3) Cool the reaction solution obtained in step 2) to crystallize, so that dichlorosulfonimide acid precipitates in crystal form. Remove excess organic solvent by nitrogen pressure filtration. The remaining solid is first heated to melt and then cooled to crystallize. Repeat the operation 3 to 5 times to finally obtain dichlorosulfonimide acid.

2. The method for preparing dichlorosulfonylimine as described in claim 1, characterized in that, In step 1), the aminosulfonyl chloride and sulfur trioxide are in a molar ratio of 1:(1.02~1.05).

3. The method for preparing dichlorosulfonylimine as described in claim 1, characterized in that, In step 1), the organic solvent is an aprotic solvent.

4. The method for preparing dichlorosulfonylimine as described in claim 1, characterized in that, In step 1), the organic solvent is one or a mixture of several of the following: acetonitrile, toluene, dichloromethane, dichloroethane, chlorobenzene, o-dichlorobenzene, and tetrahydrofuran.

5. The method for preparing dichlorosulfonylimine as described in claim 1, characterized in that, In step 1), the initiator is one of hydrogen chloride, hydroiodic acid, hydrobromic acid, and hydrofluoric acid.

6. The method for preparing dichlorosulfonylimine as described in claim 1, characterized in that, In step 2), the molar ratio of monohydroxysulfonylimine acid to thionyl chloride is 1:(2.5~5.5).

7. The method for preparing dichlorosulfonylimine as described in claim 1, characterized in that, In step 2), the organic solvent is an aprotic solvent.

8. The method for preparing dichlorosulfonylimine as described in claim 1, characterized in that, In step 2), the organic solvent is selected from one or a mixture of several of thionyl chloride, dichloromethane, toluene, and o-dichlorobenzene.

9. The method for preparing dichlorosulfonylimine as described in claim 1, characterized in that, In step 3), the melting temperature during the purification of dichlorosulfonylimide acid by melt crystallization is 30~45℃.

10. The method for preparing dichlorosulfonylimine as described in claim 1, characterized in that, In step 3), the cooling crystallization temperature during the purification of dichlorosulfonylimide acid by the melt crystallization method is -10 to 0℃.

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