US008377406B1 (12) United States Patent (10) Patent No.: US 8,377,406 B1 Singh et al. (45) Date of Patent: Feb. 19, 2013 (54) SYNTHESIS OF 2012,0070358 A1 3/2012 Morinaka et al. 2012fO184763 A1 7/2012 Kurumaya et al. BIS(FLUOROSULFONYL)IMIDE 2012/O193587 A1 8/2012 Sakuraba et al. (75) Inventors: Rajendra P. Singh, Broomfield, CO FOREIGN PATENT DOCUMENTS (US); Jerry Lynn Martin, Superior, CO WO 2009/123328 * 10/2009 (US); Joseph Carl Poshusta, WO WO 2010/010613 1, 2010 Broomfield, CO (US) WO WO 2011, O655O2 6, 2011 WO WO 2012/O26360 3, 2012 (73) Assignee: Boulder Ionics Corporation, Arvada, OTHER PUBLICATIONS CO (US) Adam, B.D. et al., “Cost comparison of Methyl Bromide and Sulfuryl (*) Notice: Subject to any disclaimer, the term of this Fluoride (ProFumeR) for fumigating food processing facilities, patent is extended or adjusted under 35 warehouses, and cocoa beans.” 10th International Working Confer U.S.C. 154(b) by 0 days. ence on Stored Product Protection, Julius-Kiihin-Archiv, 2010, vol. 425, pp. 314-321. Technical Bulletin by Dow AgroSciences on Sulfuryl Fluoride gas (21) Appl. No.: 13/598,570 fumigant, 2012. Beran, M. et al. "A new route to the syntheses of alkali metal (22) Filed: Aug. 29, 2012 bis(fluorosulfuryl)imides: Crystal structure of LiN(SO2F) 2.” Poly hedron, 2006, vol. 25, 1292-1298. (51) Int. Cl. Kubota, K. et al., “Binary and ternary mixtures of MFSA (M=Li, K. C07C303/00 (2006.01) Cs) as new inorganic ionic liquids.” ECS Transactions, 2009, vol. (52) U.S. Cl. ..................... 423/365; 423/386; 423/415.1; 16(24), pp. 91-98. 423/491; 423/617; 564/83: 568/35 Xu, K. et al., “Effect of N-substituents on protonation chemistry of trichlorophosphazenes.” Inorg. Chim. Acta, 2000, vol. 298, pp. (58) Field of Classification Search .................. 423/365, 16-23. 423/386, 491, 617,415.1; 564/83: 568/28-37 Han, H.-B., et al., “Lithium bis(fluorosulfonyl)imide (LiFSI) as con See application file for complete search history. ducting salt for nonaqueous liquid electrolytes for lithium-ion bat teries: Physicochemical and electrochemical properties,” J. Power (56) References Cited Sources, 2011, vol. 196, pp. 3623-3632. Zatloukalova, J. "Deregulation of Cell Proliferation and Apoptosis by U.S. PATENT DOCUMENTS Xenobiotics and Cytostatics', Masarykova Univerzita V Bme, Ph.D. 5,256,821 A 10, 1993 Armand Thesis, 2008. 5,874,616 A 2f1999 Howells et al. 6,235,921 B1 5/2001 Kobayashi et al. * cited by examiner 6,350,545 B2 2/2002 Fanta et al. 7,253,317 B2 8, 2007 Cernik et al. 7,605,271 B2 10/2009 Uchimura et al. Primary Examiner — Steven Bos 7,741,518 B2 6/2010 Yatsuyanagi et al. (74) Attorney, Agent, or Firm — Don D. Cha; Hamilton 8,026,391 B2 9, 2011 Uotani et al. DeSanctis & Cha, LLP 8,134,027 B2 3/2012 Okumura et al. 2005/0240052 A1 10/2005 Komata et al. (57) ABSTRACT 2007.0043231 A1 2/2007 Hammami et al. 2009.0118543 A1 5/2009 Yatsuyanagi et al. The present invention provides methods for producing bis 2009.0143613 A1 6, 2009 Uotani et al. (fluorosulfonyl) compounds of the formula: 2010.0022803 A1 1/2010 Nanmyo et al. 2010.0044617 A1 2/2010 Nishida et al. 2010/0305345 A1 12/2010 Kurumaya et al. by contacting a nonfluorohalide compound of the formula: 2011/OO3471.6 A1* 2/2011 Okumura et al. ............... 556/69 2011/01783 06 A1 7, 2011 Michot X—S(O)2. Z-S(O)2—X 2011/026999.0 A1 11/2011 Honda et al. 2012,0009113 A1 1/2012 Honda et al. with bismuth trifluoride under conditions sufficient to pro 2012fOO 14859 A1 1/2012 Honda et al. duce the bis(fluorosulfonyl) compound of Formula I, where Z 2012/002O867 A1 1/2012 Morinaka et al. and X are those defined herein. 2012/0022269 A1 1/2012 Honda et al. 2012/0041233 A1 2/2012 Sato et al. 19 Claims, No Drawings US 8,377,406 B1 1. 2 SYNTHESIS OF years after its identification as a promising material for elec BIS(FLUOROSULFONYL)IMIDE trochemical applications. This is due at least in part to the cost and difficulty of synthesizing high-purity salts of the FSI FIELD OF THE INVENTION anion. While many processes for producing HFSI are known, each of the known methods for synthesizing HFSI has disad The present invention relates to a method for producing Vantages or short comings. For example, one method for bis(fluorosulfonyl) compounds of the formula F S(O) synthesizing HFSI uses urea (NHCONH2) and fluorosul Z S(O), F from a nonfluorohalide compound of the for fonic acid (FSOH). One of the major disadvantages for this mula X-S(O)—Z—S(O). X using bismuth trifluoride. process is the toxicity and corrosive nature of FSO.H. More These compounds are useful in various applications includ 10 over, it is difficult to control this reaction due to local over ing as electrolytes in electrochemical devices such as batter heating during the addition of fluorosulfonic acid to the reac ies and capacitors. tion mixture. This difficulty in controlling the reaction results BACKGROUND OF THE INVENTION in an unpredictable yield of the desired product. See, for 15 example, Chem. Ber:, 1962, 95,246-248 (61% yield) and L. Fluorine has the highest electronegativity in the periodic Zatloukalova, Thesis, UJEP Brno, 1979 (14.5% yield). table. As such, incorporation of fluorine into molecules often Another method for synthesizing HFSI involves fluorinat results in a significant change in the physical and chemical ing bis(chlorosulfonyl)-imide (i.e., HCSI) with arsenic trif properties of molecules. Some fluorine-containing com luoride (ASE). In this reaction, HCSI is treated with Ash. pounds have high electrochemical stability and are useful in Arsenic trifluoride is toxic and because it has a high vapor electrochemical energy storage devices such as batteries and pressure, it is particularly difficult to handle on an industrial electric double layer capacitors (EDLCs). For example, flu scale. A typical reaction uses 1:8.6 ratio of HCSI to ASE. This orinated salts such as lithium bis(trifluoromethylsulfonyl) means a large excess of highly dangerous arsenic trifluoride is imide (LiTFSI) have been used as components of electrolytes used. for batteries and EDLCs. These salts have advantageous 25 HFSI can also be prepared by the fluorination of HCSI with properties, including high thermal stability, and wide electro antimony trifluoride (SbF). The antimony trichloride chemical stability windows, but these salts can cause corro byproduct of this reaction has both high solubility in HFSI sion of cell components. U.S. Pat. No. 5,916,475 discloses and a very similar boiling point, making it very difficult to lithium bis(fluorosulfonyl)imide salts as having advantages separate from the desired product. The product of this reac over other electrolyte salts such as LiTFSI and Li PF, includ 30 tion is also typically contaminated with chloride, which ren ing better temperature stability, higher conductivity, and ders the product unsuitable for electrochemical applications. lower corrosion rates. Due at least in part to these advantages Yet another method for producing HFSI involves reacting there has been extensive research activity in synthesis, struc HCSI with excess anhydrous HF at high temperature. See, for tural and electrochemical aspects of various fluorine contain example, U.S. Pat. No. 7,919,629. The yield of this reaction is ing compounds including bis(fluorosulfonyl)imide (HFSI). 35 at most 60%, with the product contaminated with fluorosul its metal salts and ionic liquids comprising Such compounds. fonic acid that is produced from the decomposition of HCSI. Bis(fluorosulfonyl)imides and ionic liquids comprising the This by-product is difficult to remove on an industrial scale as same have been shown to be useful as electrolytes in lithium the boiling point is close to that of HFSI. ion batteries and ultracapacitors. Bis(fluorosulfonyl)imide is Synthesis of lithium and sodium salts of HFSI has been a relatively strong acid and forms various stable metal salts. 40 reported. See, for example, Electrochemical Society Trans These compounds are useful as electrolytes and the lithium actions, 2009, 24, pp. 91-98; and Polyhedron, 2006, 25, pp. salt of bis(fluorosulfonyl)imide (i.e., LiFSI) is particularly 1292-1298. In particular, lithium salt of HFSI was synthe useful in batteries and ultracapacitors. sized by the metathesis reaction of potassium salt of HFSI Lithium ion batteries are particularly attractive as a sec (i.e., KFSI) with lithium perchlorate (LiCIO). This reaction ondary battery due to their high energy density and high 45 also produces potassium perchlorate (KClO4), which is an power density. Batteries with electrolytes comprising ionic explosive compound. HFSI has also been synthesized from liquids of bis(fluorosulfonyl)imide and/or its metal salt have KFSI using perchloric acid. This reaction also produces shown to be safer, more reliable, and possess higher energy KClO4. These processes are not suitable for commercial scale density relative to many conventional lithium ion batteries. synthesis due to explosive nature of perchloric acid, lithium Ambient temperature ionic liquids are useful and safe elec 50 perchlorate, and potassium perchlorate. trolytes due to their non-volatility, non-flammability, wide U.S. Pat. No. 7.253,317 describes the synthesis of HFSI electrochemical stability window and high ionic conductiv from bis(chlorosulfonyl)imide or HCSI, using potassium ity. Among various ionic liquids, bis(fluorosulfonyl)imide fluoride (KF) and other monovalent fluorides. This process is based ionic liquids typically show a significantly lower vis relatively slow (22 hours), typically requires Volatile organic cosity, lower melting point and higher ionic conductivity than 55 Solvents (nitromethane) and yields a product with too high of other ionic liquids.