Preparation method of bis (chlorosulfonyl) imide acid
By using ionic liquids within 100°C as the reaction medium, the problems of high toxic pollution, high cost and long reaction time in the preparation method of dichlorosulphonimide in the prior art were solved, and efficient and rapid reaction was achieved, and the purity and yield of the product were improved.
Patent Information
- Application Number
- CN202510374411.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-27
- Publication Date
- 2025-06-13
AI Technical Summary
The preparation method of dichlorosulphonimidic acid in the prior art has problems such as contamination of highly toxic compounds, high cost and long reaction time, and the heterogeneous reaction of sulfamic acid leads to slow reaction and difficult to improve purity.
The ionic liquid in liquid form within 100°C was used as the reaction medium, and chlorosulphonic acid was used as anion and dimethylamine, trimethylamine, etc. were used as cations to significantly improve the solubility of sulfamic acid, and the reaction was carried out by dropping the sulfoxide chloride.
It significantly improves the synthesis efficiency of dichlorosulphonimide, shortens the reaction time, reduces the use of chlorosulphonic acid and sulfoxide chloride, improves the purity and yield of the product, and reduces impurities and chlorosulphonic acid residues.
Smart Images
Figure BDA0005332272790000081 
Figure BDA0005332272790000091
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of fine chemical industry, and particularly relates to a method for preparing dichlorosulfonylimide acid. Background Art
[0002] Lithium bis(fluorosulfonyl)imide can be used as an electrolyte or an additive for electrolyte in power lithium batteries. It is an electrolyte in the electrolyte of power lithium batteries, especially for the development and application of solid-state batteries, and the demand for lithium bis(fluorosulfonyl)imide is increasing. As an important raw material for lithium bis(fluorosulfonyl)imide, the research on the preparation method of dichlorosulfonylimide acid has been reported in the prior art. For example, cyanogen chloride and sulfur trioxide are used as raw materials to first prepare isocyanic acid chlorosulfonate and then react with chlorosulfonic acid to prepare dichlorosulfonylimide acid. However, this preparation method has the following disadvantages: Since cyanogen chloride is a highly toxic compound, the synthesis process has relatively high pollution and danger, and the price of isocyanic acid chlorosulfonate is relatively high, which is not suitable for large-scale industrial production.
[0003] The prior art also discloses a method for preparing dichlorosulfonylimide acid using thionyl chloride, chlorosulfonic acid and sulfamic acid as raw materials. The synthesis process is simple, the material source is relatively easy, and the raw material price is relatively cheap. Currently, it is the mainstream synthesis route. However, this preparation method has the following disadvantages: Since sulfamic acid is a solid, the reaction is a heterogeneous reaction, resulting in a relatively slow reaction. Even if the feeding ratio is one molar equivalent and the reaction is carried out for 24 hours, there will still be residues of sulfamic acid solid.
[0004] Although the prior art proposes that the reaction time can be shortened by reducing the particle size of sulfamic acid and carrying out the reaction under pressure, this method has relatively high requirements for the reaction equipment. First, it is necessary to grind and crush sulfamic acid to increase the specific surface area of the solid reactant. Second, the high-pressure reaction increases the safety hazard.
[0005] In addition, the purity of dichlorosulfonylimide acid has a great influence on the product quality of the later-prepared lithium bis(fluorosulfonyl)imide. Generally, vacuum rectification is used to improve the purity of dichlorosulfonylimide acid. However, due to the relatively high boiling point of dichlorosulfonylimide acid, even when rectifying at a relatively high temperature (greater than 130 °C), a relatively high vacuum degree is required and it takes a long time to complete.
[0006] Secondly, in the case of excessive sulfamic acid, side reactions will occur with dichlorosulfonylimide acid. Dichlorosulfonylimide acid can interact with each other under high-temperature conditions, undergoing nucleophilic substitution, condensation and other reactions, causing the molecules to gradually connect into long-chain linear polymerization by-products. There is an urgent need for a method that can increase the reaction rate and reduce impurities. Summary of the Invention
[0007] To solve the above problems, the present invention provides a method for preparing dichlorosulfonylimide acid, the core of which is to use a kind of ionic liquid that is liquid within 100 °C. The characteristics of this kind of ionic liquid are that it uses chlorosulfonic acid, one of the raw materials used in the reaction, as the anion, and dimethylamine, trimethylamine, triethylamine, tributylamine and their chlorinated products that can dissolve sulfamic acid well as the cation.
[0008] On the one hand, this kind of ionic liquid has the stability of chlorosulfonic acid in the reaction system and the high solubility of organic amines in sulfamic acid.
[0009] On the other hand, this kind of ionic liquid has no vapor pressure, will not affect the quality of the dichlorosulfonylimide acid obtained by later evaporation, and because of its good stability, it can be recycled repeatedly. The specific technical solution is as follows:
[0010] A method for preparing dichlorosulfonylimide acid, comprising the following steps: adding the ionic liquid into a kettle, then adding sulfamic acid to dissolve it, then adding chlorosulfonic acid into the reaction vessel at one time, and then dropping thionyl chloride into the reaction vessel, and reacting under certain conditions to obtain dichlorosulfonylimide acid.
[0011] Further, the anion of the ionic liquid is chlorosulfonic acid, and the cation is dimethylamine, trimethylamine, triethylamine, tributylamine and their chlorinated products. The mass ratio of the amount of the ionic liquid to the mass of sulfamic acid is 1:2 - 5.
[0012] Further, the molar ratio of sulfamic acid, chlorosulfonic acid, and thionyl chloride is 1:(1 - 1.2):(2 - 2.5).
[0013] Further, the dissolution temperature of sulfamic acid and the ionic liquid is 40 - 60 °C.
[0014] Further, the dropping time of thionyl chloride is 0.5 - 1 h, and the dropping temperature is 60 - 70 °C;
[0015] Further, the reaction temperature is 75 - 90 °C, and the reaction time is 5 - 10 h.
[0016] Further, the low vacuum degree is less than -0.098 MPa.
[0017] Currently, dichlorosulfonylimide acid is mainly synthesized by a one-step method using sulfamic acid, chlorosulfonic acid, and thionyl chloride as raw materials. Among them, the usage amounts of thionyl chloride and chlorosulfonic acid are excessive, and both of them are both reaction reagents and reaction solvents. However, considering atom economy, the usage amounts of thionyl chloride and chlorosulfonic acid are not far excessive, and the solubility of sulfamic acid in the two is not ideal, so the mass transfer efficiency is low and the reaction time is long.
[0018] The ionic liquid used in this application can fully dissolve sulfamic acid before the reaction starts, and then be fully mixed with chlorosulfonic acid and thionyl chloride. After the reaction is completed, the unreacted chlorosulfonic acid and thionyl chloride are recovered under a low vacuum, and the product of dichlorosulfonylimide acid is collected under a high vacuum. After collection, the ionic liquid in the kettle can be directly reused for the next batch of reactions.
[0019] Advantages of this application:
[0020] 1. Significantly improve the synthesis efficiency of dichlorosulfonylimide acid and greatly shorten the reaction time;
[0021] 2. Reduce the usage amount of chlorosulfonic acid and thionyl chloride, reduce the subsequent environmental protection treatment pressure and save costs;
[0022] 3. Significantly reduce the residue of chlorosulfonic acid in dichlorosulfonylimide acid. Specific implementation mode
[0023] The present invention provides a preparation method of dichlorosulfonylimide acid, which has high efficiency, fast reaction, no kettle residue and high product quality. Specifically, it includes the following steps:
[0024] Add chlorosulfonic acid-based ionic liquid into the reactor, and then add sulfamic acid and heat to dissolve it;
[0025] Add chlorosulfonic acid into the reactor to mix with sulfamic acid and ionic liquid, and then slowly dropwise add thionyl chloride;
[0026] After mixing, raise the temperature for reaction. After the reaction is completed, first evaporate and separate thionyl chloride and chlorosulfonic acid under a low vacuum, and then evaporate and collect the product of dichlorosulfonylimide acid under a high vacuum;
[0027] After the raw materials and products are separated, the remaining ionic liquid is directly reused for the next batch of reactions.
[0028] The experimental process of the present invention will be described in detail below in combination with specific embodiments.
[0029] Example 1
[0030] Accurately weigh 485.45 g of tributylamine chlorosulfonate ionic liquid and 97.09 g of sulfamic acid, add them to a 2000 mL flask, then heat up to 50 °C. After the sulfamic acid is fully dissolved, add 116.52 g of chlorosulfonic acid to the flask at one time. After heating up to 65 °C, slowly add 237.94 g of thionyl chloride to the reaction vessel drop by drop. Add a condenser above the flask to reflux thionyl chloride, and absorb hydrogen chloride and sulfur dioxide in the tail gas. Thionyl chloride is added dropwise within 30 min, and then the temperature is continuously raised to 90 °C according to the reaction situation. The subsequent reaction time is about 10 h. At this moment, the liquid in the flask is light yellow, clear and transparent, without solid suspended matter. Adopt the vacuum distillation method to remove the residual thionyl chloride and chlorosulfonic acid in the reaction flask. When removing, the temperature in the reaction vessel does not exceed 90 °C, and the reaction vacuum is less than -0.098 MPa. Then distill the crude product with a two-stage rotary vane vacuum pump, and the distillation temperature does not exceed 90 °C to obtain 211.58 g of dichlorosulfonyl imidic acid. Based on sulfamic acid, the yield of dichlorosulfonyl imidic acid is 98.32%, the purity is 99.51%, the residual chlorosulfonic acid is 0.25%, and the impurities are 0.24%.
[0031] Example 2
[0032] Accurately weigh 194.18 g of dimethylamine chlorosulfonate ionic liquid and 97.09 g of sulfamic acid, add them to a 1000 mL flask, then heat up to 40 °C. After the sulfamic acid is fully dissolved, add 122.35 g of chlorosulfonic acid to the flask at one time. After heating up to 60 °C, slowly add 237.94 g of thionyl chloride to the reaction vessel drop by drop. Add a condenser above the flask to reflux thionyl chloride, and absorb hydrogen chloride and sulfur dioxide in the tail gas. Thionyl chloride is added dropwise within 35 min, and then the temperature is continuously raised to 80 °C according to the reaction situation. The subsequent reaction time is about 9 h. At this moment, the liquid in the flask is light yellow, clear and transparent, without solid suspended matter. Adopt the vacuum distillation method to remove the residual thionyl chloride and chlorosulfonic acid in the reaction flask. When removing, the temperature in the reaction vessel does not exceed 90 °C, and the reaction vacuum is less than -0.098 MPa. Then distill the crude product with a two-stage rotary vane vacuum pump, and the distillation temperature does not exceed 90 °C to obtain 212.40 g of dichlorosulfonyl imidic acid. Based on sulfamic acid, the yield of dichlorosulfonyl imidic acid is 98.69%, the purity is 99.50%, the residual chlorosulfonic acid is 0.19%, and the impurities are 0.31%.
[0033] Example 3
[0034] Accurately weigh 291.27 g of trimethylamine chlorosulfonate ionic liquid and 97.09 g of sulfamic acid, add them to a 1000 mL flask, then heat up to 45 °C. After the sulfamic acid is fully dissolved, add 139.83 g of chlorosulfonic acid to the flask at one time. After heating up to 70 °C, slowly add 279.58 g of thionyl chloride to the reaction vessel drop by drop. Add a condenser above the flask to reflux thionyl chloride, and absorb hydrogen chloride and sulfur dioxide in the tail gas. Thionyl chloride is added dropwise within 50 min. Subsequently, the temperature is continuously raised to 75 °C according to the reaction situation. When the subsequent reaction time is about 7 h, the liquid in the flask is a light yellow clear and transparent liquid without solid suspended matter at this moment. Use the vacuum distillation method to remove the residual thionyl chloride and chlorosulfonic acid in the reaction flask. When removing, the temperature in the reaction vessel does not exceed 90 °C, and the reaction vacuum degree is less than -0.098 MPa. Then distill the crude product with a two-stage rotary vane vacuum pump, and the distillation temperature does not exceed 90 °C to obtain 213.304 g of dichlorosulfimidic acid. Based on sulfamic acid, the yield of dichlorosulfimidic acid is 99.10%, the purity is 99.49%, the residual chlorosulfonic acid is 0.18%, and the impurity is 0.33%.
[0035] Example 4
[0036] Accurately weigh 388.36 g of triethylamine chlorosulfonate ionic liquid and 97.09 g of sulfamic acid, add them to a 2000 mL flask, then heat up to 45 °C. After the sulfamic acid is fully dissolved, add 134.00 g of chlorosulfonic acid to the flask at one time. After heating up to 70 °C, slowly add 474.25 g of thionyl chloride to the reaction vessel drop by drop. Add a condenser above the flask to reflux thionyl chloride, and absorb hydrogen chloride and sulfur dioxide in the tail gas. Thionyl chloride is added dropwise within 60 min. Subsequently, the temperature is continuously raised to 80 °C according to the reaction situation. When the subsequent reaction time is about 5 h, the liquid in the flask is a light yellow clear and transparent liquid without solid suspended matter at this moment. Use the vacuum distillation method to remove the residual thionyl chloride and chlorosulfonic acid in the reaction flask. When removing, the temperature in the reaction vessel does not exceed 90 °C, and the reaction vacuum degree is less than -0.098 MPa. Then distill the crude product with a two-stage rotary vane vacuum pump, and the distillation temperature does not exceed 90 °C to obtain 213.95 g of dichlorosulfimidic acid. Based on sulfamic acid, the yield of dichlorosulfimidic acid is 99.01%, the purity is 99.10%, the residual chlorosulfonic acid is 0.59%, and the impurity is 0.31%.
[0037] Comparative Example 1
[0038] 123.01 g of chlorosulfonic acid was added to a three-necked flask at one time. Then, 97.09 g of sulfamic acid was added and stirring was started. After heating to 65 °C, 310.05 g of thionyl chloride was slowly added to the reaction vessel by dropping. A condenser was added above the flask to reflux thionyl chloride, and the tail gas was used to absorb hydrogen chloride and sulfur dioxide. Thionyl chloride was added dropwise within 6 h. Subsequently, the temperature was continuously raised to 95 °C according to the reaction situation, and the subsequent reaction time was about 24 hours. In the later stage of the reaction, sulfamic acid was completely dissolved, and the flask was filled with a light yellow clear and transparent liquid without solid suspension. The residual thionyl chloride and chlorosulfonic acid in the reaction flask were removed by vacuum distillation. During the removal, the temperature in the reaction vessel did not exceed 90 °C, and the reaction vacuum was less than -0.098 MPa. Then, the crude product was distilled with a two-stage rotary vane vacuum pump at a distillation temperature not exceeding 90 °C to obtain 208.43 g of dichlorosulfonyl imidic acid. Based on sulfamic acid, the yield of dichlorosulfonyl imidic acid was 95.30%, the purity was 97.91%, the residual chlorosulfonic acid was 1.09%, and the impurities were 1.00%.
[0039] Comparative Example 2
[0040] 124 g of chlorosulfonic acid, 97 g of sulfamic acid, and 310 g of thionyl chloride were added to a three-necked flask at one time. Stirring was started, and a condenser was added above the flask to reflux thionyl chloride. The tail gas was used to absorb hydrogen chloride and sulfur dioxide. According to the reaction progress, the external temperature was maintained about 5 °C higher than the internal temperature. Subsequently, the temperature was continuously adjusted to 100 °C. The total reaction time of the whole reaction cycle was about 25 hours. Sulfamic acid was completely dissolved, and the flask was filled with a light yellow clear and transparent liquid without solid suspension. The residual thionyl chloride and chlorosulfonic acid in the reaction flask were removed by vacuum distillation. During the removal, the temperature in the reaction vessel did not exceed 90 °C, and the reaction vacuum was less than -0.098 MPa. Then, the crude product was distilled with a two-stage rotary vane vacuum pump at a distillation temperature not exceeding 90 °C to obtain 216.63 g of dichlorosulfonyl imidic acid. Based on sulfamic acid, the yield of dichlorosulfonyl imidic acid was 93.89%, the purity was 92.81%, the residual chlorosulfonic acid was 3.48%, and the impurities were 3.71%.
[0041] Comparative Example 3
[0042] Add 122.35 g of chlorosulfonic acid and 97 g of sulfamic acid, start stirring, add a condenser above the flask to reflux thionyl chloride, absorb hydrogen chloride and sulfur dioxide in the tail gas, heat up to 45 °C, add 300 g of thionyl chloride dropwise into the flask within 120 min. According to the reaction progress, maintain the external temperature about 5 °C higher than the internal temperature. Subsequently, continuously adjust the temperature to rise to 105 °C. The total reaction time of the whole reaction cycle is about 25 hours. The sulfamic acid will dissolve completely, and at this moment, the liquid in the flask is a light yellow clear and transparent liquid without solid suspended matter. Adopt the vacuum distillation method to remove the residual thionyl chloride and chlorosulfonic acid in the reaction flask. When removing, the temperature in the reaction vessel does not exceed 90 °C, and the reaction vacuum degree is less than -0.098 MPa. Then use a two-stage rotary vane vacuum pump to distill the crude product, and the distillation temperature does not exceed 90 °C to obtain 208.91 g of dichlorosulfonyl imidic acid. Calculated based on sulfamic acid, the yield of dichlorosulfonyl imidic acid is 93.82%, the purity is 96.17%, the residual chlorosulfonic acid is 0.61%, and the impurities are 1.22%.
[0043] The reaction time, the yield of dichlorosulfonyl imidic acid, the purity of dichlorosulfonyl imidic acid, the residual chlorosulfonic acid, and the impurity content in Examples 1-4 and Comparative Examples 1-3 are shown in Table 1 as follows:
[0044] Table 1
[0045]
[0046]
[0047] In summary, after the dichlorosulfonyl imidic acid prepared by recycling the kettle residue is purified, its purity is not lower than that of the dichlorosulfonyl imidic acid synthesized by normal feeding in the existing process, meeting the raw material requirements of the downstream process. For the process of synthesizing dichlorosulfonyl imidic acid using the kettle residue, the overall yield is much greater than that of the existing process.
[0048] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.
Claims
1. A method for preparing bischlorosulfonyl imide acid, characterized in that: The following steps are involved: S1, adding ionic liquid into a reactor, and then adding aminosulfonic acid and heating to dissolve it; S2, adding chlorosulfonic acid into the reactor at one time, mixing with aminosulfonic acid and ionic liquid, and then slowly adding thionyl chloride dropwise; S3, after the mixing is completed, the temperature is raised to react, and after the reaction is completed, thionyl chloride and chlorosulfonic acid are separated by evaporation at a low vacuum, and then the bischlorosulfonyl imide acid product is collected by evaporation at a high vacuum; S4. After the raw materials and products are separated, the remaining ionic liquid is directly reused for the next batch of reactions.
2. The method for preparing bischlorosulfonyl imide acid according to claim 1, characterized in that: The anion in the ionic liquid is chlorosulfonic acid, and the cation is dimethylamine, trimethylamine, triethylamine, tributylamine and their chlorinated products.
3. The method for preparing bischlorosulfonyl imide acid according to claim 1, characterized in that: The mass ratio of the ionic liquid to aminosulfonic acid is 1:2-5.
4. The method for preparing bischlorosulfonyl imide acid according to claim 1, characterized in that: The molar ratio of the aminosulfonic acid, chlorosulfonic acid and thionyl chloride is 1:(1-1.2):(2-2.5).
5. The method for preparing bischlorosulfonyl imide acid according to claim 1, characterized in that: The dissolution temperature of the aminosulfonic acid and the ionic liquid is 40-60°C.
6. The method for preparing bischlorosulfonyl imide acid according to claim 1, characterized in that: The thionyl chloride addition time is 0.5 to 1 h, and the addition temperature is 60 to 70°C.
7. The method for preparing bischlorosulfonyl imide acid according to claim 1, characterized in that: The reaction temperature is 75-90°C and the reaction time is 5-10h.
8. The method for preparing bischlorosulfonyl imide acid according to claim 1, characterized in that: The low vacuum degree is less than -0.098MPa.