A kind of preparation method of bisfluorosulfonimide salt solution

Abstract

The application belongs to the technical field of electrolyte additives, and in particular relates to a new process for bisfluorosulfonimide salt solution. The invention provides an inventive process, including S1: mixing and stirring the solvent, the compound of general formula II and the compound of general formula I, and reacting; S2: then separating the solid and liquid to obtain difluorosulfonyl sulfonyl, which can be directly used in the battery electrolyte Amine salt solution.

Description

technical field [0001] The application belongs to the technical field of electrolyte additives, and in particular relates to a preparation method of a bisfluorosulfonimide salt solution. Background technique [0002] Bisfluorosulfonimide salts have broad application prospects in the field of electrolytes, especially lithium bisfluorosulfonimide salts, which have suitable electrical conductivity, high thermal stability and electrochemical stability. It is an indispensable high-tech product; it can also be used as a Lewis acid catalyst and has important industrial production value. [0003] At present, a typical method for preparing a bisfluorosulfonimide salt solution is to first prepare a crude bisfluorosulfonimide salt body, recrystallize to obtain a finished product, and then dissolve in a solvent to obtain a bisfluorosulfonimide salt solution. [0004] The method for preparing bisfluorosulfonimide salt is basically to first synthesize bischlorosulfonimide (R.Appel et al,...

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Problems solved by technology

[0004] The method for preparing bis-fluorosulfonimide salts is basically to first synthesize bis-chlorosulfonimide (R.Appel et al, Chem.Ber.1962,95,625); R.Appel et al, Chem.Ber.1962, 95,1753; E.A.Fadia, US4315935,1982; M.Beran et al, Z.Anorg.Allg.Chem.2005,631,55), wherein M.Beran et al proposed a one-step synthesis method that can overcome problems such as separation and toxicity , has been widely used in recent years. This method puts sulfamic acid, chlorosulfonic acid, and thionyl chloride in a "one pot" reaction and distills under reduced pressure to obtain bisfluorosulfonimide. However, due to the high boiling point of the product, the distillation The process of bischlorosulfonimide compound consumes a lot of energy

[0005] Reaction of dichlorosulfonimide with hydrofluoric acid to synthesize bisfluorosulfonimide, as described in patents CN104755418A and CN101654229A, but requires high-pressure reaction and requires high equipment

Then bisfluorosulfonimide is neutralized with alkali, as US8377406 discloses the method that bisfluorosulfonimide directly reacts with lithium carbonate in aqueous solution to prepare bisfluorosulfonimide lithium, but bisfluorosulfonimide and Water decomposes after violent heat release. The patented method of preparing bisfluorosulfonimide aqueous solution by ultra-low temperature (-78°C) solves the problem of violent heat release when bisfluorosulfonimide dissolves in water, but the energy consumption is huge. More importantly, lithium bisfluorosulfonyl imide has very good water solubility, and it is easy to decompose when heated in the water system, and the extraction efficiency is very low, which is not suitable for industrial production

[0006] It has also been reported that difluorosulfonimide salts can be directly obtained by reacting dichlorosulfonimide with fluoride salts, such as US2004097757, which uses dichlorosulfonimide to directly react with lithium fluoride to prepare lithium bisfluorosulfonimide However, the obvious disadvantage is that a large amount of corrosive tail gas hydrogen fluoride is produced, and industrial production is difficult

[0007] EP2894146 reported the preparation of dichlorosulfonimide salt with dichlorosulfonimide, and then reacted with fluoride salt to generate bisfluorosulfonimide salt, which made the reaction process too complicated and resulted in a decrease in the total yield of the product

[0008] The existing technologies basically require the preparation of bisfluorosulfonimide and bischlorosulfonimide, both of which are highly acidic and corrosive, so the process is cumbersome, the products are difficult to separate, and the requirements for reaction equipment are high. Difficulty, high energy consumption, environmental pollution and other defects make it difficult to realize the industrialization of bisfluorosulfonimide salt

[0009] And the current process has an obvious defect. Due to the defect of the preparation process, it is necessary to obtain the crude product first, then recrystallize to obtain the finished product, and then re-dissolve it in the subsequent electrolyte preparation process, which causes a great waste of resources. low efficiency

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