A new process for bisfluorosulfonyl imide salt

Abstract

The invention provides a preparation method of bisfluorosulfonimide salt, comprising the following steps: S1: reacting N-alkyl-substituted bisfluorosulfonimide and salt in a solvent system to obtain a crude product; S2 : Crystallized and dried to obtain bisfluorosulfonimide salt. No water is produced in the reaction process of the present invention, the N-alkyl-substituted bisfluorosulfonimide has stable properties, no corrosive substances are produced in the whole reaction, and the three wastes are less, suitable for large-scale production, and high-purity battery-grade bisfluorosulfonimide can be obtained. Fluorosulfonylimide salt has great implementation value and social and economic benefits.

Description

Technical field [0001] The invention relates to a preparation method of bisfluorosulfonimide salt, and more specifically a new process for bisfluorosulfonimide salt. Background technique [0002] Bisfluorosulfonimide salt (hereinafter referred to as: MFSI) has a wide range of applications in the electrolyte neighborhood. For example, bisfluorosulfonimide potassium salt (also known as KFSI) is used as an additive for supercapacitors. Used as an electrolyte (also known as LiFSI): US Patent US5916475 discloses a fluorine-containing lithium salt that has better thermal and chemical stability, higher conductivity and lower corrosion rate than LiTFSI and LiPF6- Lithium bisfluorosulfonimide (LiFSI), the Japanese catalyst realized industrial production in 2013. At present, Japanese and Korean companies have mixed LiPF6 and LiFSi on high-end occasions, and it is considered that it may replace LiPF6 as a kind of bisfluorolithium. Salt, in lithium batteries and supercapacitors, will have a...

AI Technical Summary

Problems solved by technology

[0003] At present, the typical preparation method of MFSI is basically to first synthesize bischlorosulfonimide (HCSI for short), then synthesize bischlorosulfonimide compound (HN[SO2Cl] 2 ), (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 etc. have proposed a one-step synthesis method that can overcome problems such as separation and toxicity, and has been widely adopted in recent years. This method combines sulfamic acid, chlorosulfonic acid, chlorinated The sulfone is reacted in a "one pot" and distilled under reduced pressure to obtain HN[SO 2 Cl] 2 , but due to the high boiling point of the product, the process of distilling bischlorosulfonimide compounds consumes a lot of energy

[0004] Reaction of HCSI with hydrofluoric acid to synthesize bisfluorosulfonimide (referred to as HFSI), as described in patents CN104755418A and CN101654229A, but requires high-pressure reaction and requires high equipment

Then HFSI is neutralized with alkali, such as US8377406 discloses the method that bisfluorosulfonimide (HFSI) directly reacts with lithium carbonate in aqueous solution to prepare LiFSI, but HFSI decomposes after violent heat release with water, and the patent uses ultra-low temperature (-78 ℃) method to prepare HFSI aqueous solution to solve the problem of violent heat release when HFSI is dissolved in water, but the energy consumption is huge. More importantly, LiFSI has very good water solubility, and it is easy to decompose when heated in water system. The extraction efficiency is very low, not suitable for industrial production

[0005] It has also been reported that MFSI can be directly obtained by reacting HClSI with fluoride salt, such as US2004097757, when HClSI is directly reacted with LiF to prepare LiFSI, but the obvious disadvantage is that a large amount of corrosive tail gas HF is produced, and industrial production is difficult

[0006] EP2894146 reported the preparation of MCSI with HCSI, and then reacted with fluoride salt to generate MFSI, which made the reaction process too complicated, resulting in a reduction in the total yield of the product

[0007] The existing technologies basically require the preparation of HFSI and HClSI, both of which have strong acidity and corrosiveness, so the process is cumbersome, the products are difficult to separate, the requirements for reaction equipment are high, the operation is difficult, the energy consumption is large, and the environment is polluted. Defects make it difficult for LiFSI to realize industrial

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