Kettle residue recycling method in bis (chlorosulfonyl) imide production

Abstract

The invention relates to the technical field of fine chemical engineering, in particular to a method for recycling kettle residues in the production process of bis (chlorosulfonyl) imide. The innovative method focuses on effective recovery and reutilization of the kettle residues generated in the existing production process for the first time, so that many challenges such as high difficulty in treatment of the kettle residues, high environmental pollution risk, strong substance corrosivity and operation danger are successfully handled; the atom economic efficiency of a synthesis path of sulfamic acid, chlorosulfonic acid and thionyl chloride is also obviously improved. The comprehensive yield of the method can reach up to 99%, and the purity of the bis (chlorosulfonyl) imide product prepared through the kettle residue recovery reaction exceeds 98.5%, so that the strict requirement of downstream application on the purity of the bis (chlorosulfonyl) imide product is fully met.

Description

Technical Field

[0001] The invention relates to the technical field of fine chemicals, and in particular to a method for recycling still residue in the production of bischlorosulfonyl imide. Background Art

[0002] Lithium-ion batteries are chemical power sources with high energy density. They have been widely used in portable instruments, laptops, military, mobile communications, cameras, etc. In recent years, with the advancement of lithium-ion battery technology and the improvement of cost performance, they have become the first choice in the field of power vehicles and energy storage batteries, and have been widely studied and applied worldwide. The quality of lithium battery electrolyte performance directly affects important indicators such as the electrochemical performance and safety performance of lithium-ion batteries.

[0003] In recent years, researchers have found that lithium bis(fluorosulfonyl)imide has advantages over traditional lithium battery secondary battery electrolyte lithium hexafluorophosphate in many properties such as thermal stability, sensitivity to moisture, and conductivity. It has been used in many products and achieved good results.

[0004] Bischlorosulfonyl imide is an important intermediate product of bisfluorosulfonyl imide, and the production process of bischlorosulfonyl imide is also particularly important. Research on the preparation method of bischlorosulfonyl imide salt has been reported in the prior art. The prior art discloses a method for preparing bischlorosulfonyl imide using thionyl chloride, chlorosulfonic acid and aminosulfonic acid as raw materials. The synthesis process is simple, the material source is relatively easy, and the raw material price is relatively cheap. At present, as the mainstream synthesis route, the yield of bischlorosulfonyl imide in industrial production is generally above 90%, and the process conditions can reach 95% with better process conditions, but about 5-10% of the raw materials are still wasted. There are about 5% of carbides produced by high-temperature reactions in the kettle residue, 15-20% of bischlorosulfonamide, and 70-75% of by-products. The danger and difficulty of handling the kettle residue have always been a problem that plagues the industry. The current mainstream treatment scheme is to treat hazardous waste after simple neutralization and salt formation. This method has high requirements for the reaction equipment. First, the kettle residue is highly corrosive to the equipment, and the neutralization and decomposition produce sulfur dioxide and hydrogen chloride gas, which will produce huge pressure on environmental protection treatment; second, it is highly exothermic when it encounters water, and a large amount of heat is released when it encounters alkali neutralization treatment, and the operation safety is poor. Therefore, when preparing bischlorosulfonyl imide, a method that can easily handle the kettle residue is needed. Summary of the invention

[0005] The object of the present invention is to provide a method for recycling the residual bischlorosulfonyl imide in the production process, which utilizes the side reaction products in the production process of bischlorosulfonyl imide acid, that is, in the presence of excess aminosulfonic acid, which easily react with bischlorosulfonyl imide under high temperature conditions as follows: Figure 1 Side reactions shown;

[0006] The reaction produces bis(aminosulfonyl)sulfimide. There is also a situation where dichlorosulfimide is prone to dehydrogenation under high-temperature conditions to generate corresponding free radicals, and then the free radicals react with other dichlorosulfimide molecules or other free radicals to form macromolecular linear polymerization by-products. The present invention utilizes the characteristics that there are multiple active sites such as amino groups, sulfonic acid groups or connected to nitrogen atoms in the dichlorosulfimide reaction system. Under specific circumstances, the initial reaction raw materials can be used to resynthesize dichlorosulfimide again. The reaction formula is as follows Figure 2 as shown

[0007] To achieve the above object, the present invention provides the following technical solution: A method for recycling the residue in the production of dichlorosulfimide. The residue by-product in the production of dichlorosulfonic acid imide is used and reacted with thionyl chloride and chlorosulfonic acid under specific conditions. Through one-time distillation and one-time rectification, a dichlorosulfonamide imide product with higher purity can be obtained.

[0008] A method for recycling the residue in the production of dichlorosulfimide includes the following steps:

[0009] Add the residue into a reaction vessel, add chlorosulfonic acid, heat and dissolve it, then add thionyl chloride, and react at a temperature raised to 65°C to 110°C to obtain dichlorosulfimide.

[0010] Further, in the method for recycling the residue of dichlorosulfimide in the production, the mass ratio of the input residue, chlorosulfonic acid, and thionyl chloride is 1:(0.3 - 0.5):(0.6 - 1).

[0011] Further, in the method for recycling the residue of dichlorosulfimide in the production, the dissolution temperature of the residue and chlorosulfonic acid is 30 - 60°C.

[0012] Further, in the method for recycling the residue of dichlorosulfimide in the production, after the temperature is raised to 60°C to 80°C, thionyl chloride is slowly added dropwise.

[0013] Further, in the method for recycling the residue of dichlorosulfimide in the production, the time for adding thionyl chloride dropwise is 30 - 120 min.

[0014] Further, in the method for recycling the residue of dichlorosulfimide in the production, the reaction solution is distilled once, and under a pressure of -0.95 MPa, the fraction below 45 - 90°C is collected.

[0015] Further, in the method for recycling the residue of dichlorosulfimide in the production, the reaction solution is rectified for the second time, and under a negative pressure of 0.6 Pa, the fraction at 85 - 90°C is collected.

[0016] The beneficial effects of this application:

[0017] This application first recycles the kettle residue generated by the existing process and obtains high-purity dichlorosulfonylimide. It not only solves the problems of difficult kettle residue treatment, high environmental protection pressure, high corrosivity, and high danger, but also improves the atomic utilization rate of the synthesis route using sulfamic acid, chlorosulfonic acid, and thionyl chloride. Generally speaking, the overall yield can reach 99%, and the purity of the dichlorosulfonylimide obtained by recycling the kettle residue is as high as over 98.5%, fully meeting the purity requirements of downstream for dichlorosulfonylimide. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0019] Figure 1 It is the reaction equation of excessive sulfamic acid and dichlorosulfonylimide in the present invention;

[0020] Figure 2 It is the re-synthesis reaction formula of dichlorosulfonylimide in the present invention;

[0021] Figure 3 It is the liquid chromatogram of the product in Example 1 of the present invention;

[0022] Figure 4 It is the liquid chromatogram of the product in Example 2 of the present invention;

[0023] Figure 5 It is the liquid chromatogram of the product in Example 3 of the present invention;

[0024] Figure 6 It is the liquid chromatogram of the product in Comparative Example 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0026] Example 1

[0027] 200g of the kettle residue was added to a three-necked flask at one time, and then 60g of chlorosulfonic acid was added. After the temperature was raised to 30°C, the kettle residue was dissolved in the chlorosulfonic acid. Stirring was turned on, the temperature was raised to 60°C, and then 120g of thionyl chloride was slowly added to the reaction vessel by dropwise addition. A condenser was added above the flask to reflux the thionyl chloride. The tail gas absorbed hydrogen chloride and sulfur dioxide. The thionyl chloride was added dropwise within 1h. The temperature was then continuously raised to 100°C according to the reaction situation. The subsequent reaction time was 16 hours. The thionyl chloride and chlorosulfonic acid remaining 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 -0.098MPa. The crude product was then distilled with a double vane vacuum pump, and the distillation temperature did not exceed 90°C to obtain 158g of bischlorosulfonyl imide. The reaction yield was 79.9% based on the kettle residue. The purity of bischlorosulfonyl imide was 97.52% by liquid phase detection of bischlorosulfonyl imide derivatives.

[0028] Example 2

[0029] 200g of the kettle residue was added to a three-necked flask at one time, and then 80g of chlorosulfonic acid was added. After the temperature was raised to 45°C, the kettle residue was dissolved in chlorosulfonic acid. Stirring was turned on, the temperature was raised to 80°C, and then 200g of thionyl chloride was slowly added to the reaction vessel by dropwise addition. A condenser was added above the flask to reflux the thionyl chloride. The tail gas absorbed hydrogen chloride and sulfur dioxide. The thionyl chloride was added dropwise within 1h. The temperature was continuously raised to 100°C according to the reaction situation. The subsequent reaction time was 16 hours. The thionyl chloride and chlorosulfonic acid remaining in the reaction flask were removed by vacuum distillation. The temperature in the reaction vessel did not exceed 90°C during removal, and the reaction vacuum was less than -0.098MPa. The crude product was then distilled with a double vane vacuum pump, and the distillation temperature was 90°C to obtain 146g of bischlorosulfonyl imide. The reaction yield was 73% based on the kettle residue. The purity of bischlorosulfonyl imide was 98.12% by liquid phase detection of bischlorosulfonyl imide derivatives.

[0030] Example 3

[0031] Add 200 g of the residue at the bottom of the kettle into a three-necked flask at one time, then add 60 g of chlorosulfonic acid. After heating to 60 °C, the residue at the bottom of the kettle dissolves in chlorosulfonic acid. Start stirring, heat up to 80 °C, and then slowly add 120 g of thionyl chloride to the reaction vessel by dropping. Add a condenser above the flask to reflux thionyl chloride, and absorb hydrogen chloride and sulfur dioxide in the tail gas. The thionyl chloride is added dropwise within 1 h. Subsequently, the temperature is continuously raised to 100 °C according to the reaction situation, and the subsequent reaction time is 20 h. Use vacuum distillation to remove the remaining thionyl chloride and chlorosulfonic acid in the reaction flask. The temperature in the reaction vessel does not exceed 90 °C during the removal, and the reaction vacuum is less than -0.098 MPa. Then use a two-stage rotary vane vacuum pump to distill the crude product. Stop distillation when the distillation temperature reaches 95 °C to obtain 150 g of dichlorosulfonylimide. The reaction yield based on the residue at the bottom of the kettle is 75%, and the purity of dichlorosulfonylimide detected by liquid phase of dichlorosulfonylimide derivative is 98.12%.

[0032] Comparative Example 1

[0033] Add 122.35 g of chlorosulfonic acid into a three-necked flask at one time, then add 97 g of sulfamic acid and start stirring. After heating to 65 °C, slowly add 310 g of thionyl chloride to the reaction vessel by dropping. Add a condenser above the flask to reflux thionyl chloride, and absorb hydrogen chloride and sulfur dioxide in the tail gas. The thionyl chloride is added dropwise within 6 h. Subsequently, the temperature is continuously raised to 100 °C according to the reaction situation, and the subsequent reaction time is 24 h. In the later stage of the reaction, the sulfamic acid will dissolve completely, and the liquid in the flask is a light yellow clear and transparent liquid at this moment, without solid suspended matter. Use vacuum distillation to remove the remaining thionyl chloride and chlorosulfonic acid in the reaction flask. The temperature in the reaction vessel does not exceed 90 °C during the removal, and the reaction vacuum is less than -0.098 MPa. Then use a two-stage rotary vane vacuum pump to distill the crude product. The distillation temperature does not exceed 90 °C to obtain 203.9 g of dichlorosulfonylimide. The reaction yield based on sulfamic acid is 95.3%, and the purity of dichlorosulfonylimide detected by liquid phase of aniline derivative is 97.35%.

[0034] Comparative Example 2

[0035] Add 122.35 g of chlorosulfonic acid, 97 g of sulfamic acid, and 310 g of thionyl chloride into a three-necked flask at one time. Start stirring, add a condenser above the flask to reflux thionyl chloride, and absorb hydrogen chloride and sulfur dioxide in the tail gas. According to the reaction progress, maintain the external temperature always 5°C higher than the internal temperature, and then continuously adjust the temperature to 100°C. The reaction time for the entire reaction cycle is 25 hours. The sulfamic acid will dissolve completely, and the liquid in the flask is now a light yellow clear and transparent liquid without solid suspensions. Use vacuum distillation to remove the residual thionyl chloride and chlorosulfonic acid in the reaction flask. The temperature in the reaction vessel does not exceed 90°C during the removal, and the reaction vacuum is less than -0.098 MPa. Then use a two-stage rotary vane vacuum pump to distill the crude product. The distillation temperature does not exceed 90°C to obtain 200.8 g of dichlorosulfimide. The reaction yield based on sulfamic acid is 93.8%. The purity of dichlorosulfimide detected by liquid phase of aniline derivatives is 97.7%.

[0036] The product yields and the purity of dichlorosulfimide in Examples 1-3 and Comparative Examples 1-2 are shown in Table 1 as follows:

[0037] Table 1

[0038] Test item Yield Purity of dichlorosulfonylimide Example 1 79.9％ 97.52％ Example 2 73％ 98.12％ Example 3 75％ 98.12％ Comparative example 1 95.3％ 97.35％ Comparative example 2 93.8％ 97.7％

[0039] In summary, after purification treatment, the purity of dichlorosulfimide prepared by recycling the kettle residue is not lower than that of dichlorosulfimide synthesized by normal feeding in the existing process, meeting the raw material requirements of the downstream process. The overall yield of the process for synthesizing dichlorosulfimide using the kettle residue is much greater than that of the existing process.

[0040] 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 all should be covered within the protection scope of the present invention.

Claims

1. A method for recycling the residue in the production of dichlorosulfonylimide, characterized in that, It includes the following steps: adding the still residue into a reaction vessel, adding chlorosulfonic acid, heating and dissolving it, then adding thionyl chloride, and reacting at a temperature of 65°C to 110°C to obtain dichlorosulfonylimide.

2. A method for recycling the residue in the production of dichlorosulfonylimide according to claim 1, characterized in that, The mass ratio of the input still residue, chlorosulfonic acid, and thionyl chloride is 1:(0.3 - 0.5):(0.6 - 1).

3. A method for recycling the residue in the production of dichlorosulfonylimide according to claim 1, characterized in that, The dissolution temperature of the still residue and chlorosulfonic acid is 30 - 60°C.

4. A method for recycling the residue in the production of dichlorosulfonylimide according to claim 1, characterized in that, After heating to 60°C to 80°C, slowly dropwise add thionyl chloride.

5. A method for recycling the residue in the production of dichlorosulfonylimide according to claim 1, characterized in that, The time for dropwise adding thionyl chloride is 30 - 120 min.

6. A method for recycling the residue in the production of dichlorosulfonylimide according to claim 1, characterized in that, Distill the reaction solution once, and collect the fraction below 45 - 90°C under a pressure of -0.95 MPa.

7. A method for recycling the residue in the production of dichlorosulfonylimide according to claim 1, characterized in that, Rectify the reaction solution twice, and collect the fraction at 85 - 90°C under a negative pressure of 0.6 Pa.

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