WO2015051141A1

WO2015051141A1 - Methods for preparation of fluorinated sulfur-containing compounds

Info

Publication number: WO2015051141A1
Application number: PCT/US2014/058859
Authority: WO
Inventors: Samuel David Arthur; Stephen E. Burkhardt BURKHARDT; Henry Keith Chenault; Viacheslav Alexandrovich Petrov
Original assignee: E. I. Du Pont De Nemours And Company
Priority date: 2013-10-04
Filing date: 2014-10-02
Publication date: 2015-04-09

Abstract

Methods for preparing fluorinated sulfides and fluorinated sulfones are described. To prepare a fluorinated sulfides, a sulfur-containing reactant represented by the formula: R¹SM or M₂S, wherein R¹ is a C₁ to C₁₀ alkyl or fluoroalkyl, S is sulfur, and M is a cation, is reacted with a fluorinated alkyl compound. A fluorinated sulfone is formed by oxidizing the fluorinated sulfide. The fluorinated sulfones prepared by the methods disclosed herein are particularly useful as electrolyte solvents for electrochemical cells, such as a lithium ion battery, where a high purity solvent is desired.

Description

TITLE

METHODS FOR PREPARATION OF FLUORINATED SULFUR-CONTAINING COMPOUNDS

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority of United States Provisional Application Nos. 61/886686, filed on October 4, 2013.

TECHNICAL FIELD

The disclosure herein relates to the field of organic synthesis.

Specifically, this disclosure provides methods for preparing fluorinated sulfides and fluorinated sulfones.

BACKGROUND

Fluorinated sulfur-containing compounds, such as fluorinated sulfides and fluorinated sulfones, have various uses. For example, fluorinated sulfones are useful as solvents, and specifically as electrolyte solvents in

electrochemical cells, such as lithium ion batteries. Fluorinated sulfides are useful as intermediates for the preparation of fluorinated sulfones and sulfoxides. These fluorinated sulfur-containing compounds can be produced using several different methods from various starting materials. For example, structurally diverse 1 -chloro-2,2,2-trifluoroethyl sulfides can be produced from the reaction of F₃CCHBrCI and aliphatic and aromatic thiols in the presence of Na₂S₂O₄/NaHCO₃ (Pustovit et al., Synthesis 7, 1 159-1 165, 2010).

Additionally, trifluoroethylthioethers can be prepared from mercaptan salts and 1 -chloro-2,2,2-trifluoroethane (Appel et al., U.S. Patent No. 5,534,634).

However, a need still remains for simple, low cost methods of making fluorinated sulfones, which are useful as electrolyte solvents in an

electrochemical cell such as a lithium ion battery. SUMMARY

In one embodiment, there is provided herein a method of preparing a fluorinated sulfone comprising the steps of:

(a) providing a sulfur-containing reactant represented by the formula:

R¹SM (1 ) or

M₂S (2) wherein R¹ is a Ci to Cio alkyl group, optionally substituted with one or more ether oxygens, or fluoroalkyi group, optionally substituted with one or more ether oxygens, S is sulfur, and M is a cation selected from the group consisting of Na⁺, K⁺, Cs⁺, and a tetraalkylammonium cation;

(b) providing a fluorinated alkyl compound represented by the formula:

CF₂H-R²-X (3) wherein R² is either absent or a Ci to Cio alkylene group, optionally substituted with one or more ether oxygens, or fluoroalkylene

group, optionally substituted with one or more ether oxygens, the carbon atom adjacent to X in R² is not fluorinated, and X is a leaving group selected from the group consisting of Br, CI, I, and

-OSO₂R³ where R³ is aryl, F, CF₃, C₄F₉, or Ci to (_½ alkyl;

(c) contacting the sulfur-containing reactant of (a) with the fluorinated alkyl compound of (b) for a time sufficient to form a fluorinated sulfide product;

(d) oxidizing the fluorinated sulfide product to form a fluorinated sulfone product; and

(e) optionally recovering the fluorinated sulfone product.

In another embodiment, there is provided herein a method of preparing a fluorinated sulfide comprising the steps of:

(a) providing a sulfur-containing reactant represented by the formula: F SM (1 )

or

M₂S (2) wherein R¹ is a Ci to Cio alkyl group, optionally substituted with one or more ether oxygens, or fluoroalkyl group, optionally substituted with one or more ether oxygens, S is sulfur, and M is a cation selected from the group consisting of Na⁺, K⁺, Cs⁺, and a tetraalkylammonium cation;

(b) providing a fluorinated alkyl compound represented by the formula:

-OSO₂R³ where R³ is aryl, F, CF₃, C₄F₉, or Ci to (_½ alkyl;

(c) contacting the sulfur-containing reactant of (a) with the fluorinated alkyl compound of (b) for a time sufficient to form a fluorinated sulfide product; and

(d) optionally, recovering the fluorinated sulfide product from the reaction medium.

In another embodiment, there is provided herein an electrolyte composition comprising:

(a) a fluorinated sulfone selected from the group consisting of difluoromethyl methyl sulfone, difluoromethyl ethyl sulfone, and bis(difluoroethyl) sulfone; and

(b) at least one electrolyte salt.

In another embodiment, there is provided herein a fluorinated sulfone selected from the group consisting of difluoromethyl ethyl sulfone and bis(2,2- difluoroethyl) sulfone.

In another embodiment, there is provided herein fluorinated sulfide, wherein the fluorinated sulfide is 2,2-difluoroethyl isopropyl sulfide.

DETAILED DESCRIPTION

As used above and throughout the disclosure herein, the following terms, unless otherwise indicated, shall be defined as follows:

The term "alkyl group" refers to a linear or branched chain hydrocarbon group containing no unsaturation.

The term "fluoroalkyl group" refers to an alkyl group wherein at least two of the hydrogens are replaced by fluorines. Preferably, the fluoroalkyl group does not contain a -CH₂F or -CHF- group. The presence of a monofluorinated group (e.g., -CH₂F or -CHF-) may cause toxicity.

The term "alkylene group" refers to a divalent group containing carbon and hydrogen, having only carbon-carbon single bonds, and which may be linear or branched.

The term "fluoroalkylene group" refers to an alkylene group wherein at least two of the hydrogens are replaced by fluorines. Preferably, the

fluoroalkylene group does not contain a -CHF- group.

The term "aryl" refers to a substituent that is derived from an aromatic ring. As used herein an aryl can be unsubstituted or substituted.

Disclosed herein are methods for preparing fluorinated sulfides and fluorinated sulfones. One embodiment provides a simple and economical method for preparing fluorinated sulfones, which are particularly useful as electrolyte solvents for electrochemical cells, such as a lithium ion battery, for which a high purity solvent is desired. The methods disclosed herein can be used to prepare various fluorinated sulfones, including without limitation those represented by the formula: CF₂H-R⁴-SO₂-R⁵ (4) wherein R⁴ is either absent or a Ci to C₁0 alkylene group, optionally substituted with one or more ether oxygens, or fluoroalkylene group, optionally substituted with one or more ether oxygens, the carbon atom adjacent to the sulfur atom in R⁴ is not fluorinated, and R⁵ is a Ci to Cio alkyl group optionally substituted with one or more ether oxygens or a fluoroalkyi group optionally substituted with one or more ether oxygens. Preferably, neither R⁴ nor R⁵ contains a -CH₂F or - CHF- group. The presence of a monofluorinated group (i.e. -CH₂F or -CHF-) in the fluorinated sulfone may cause toxicity.

Suitable fluorinated sulfones include without limitation difluoromethyl methyl sulfone (CHF₂SO₂CH₃), difluoromethyl ethyl sulfone (CHF₂SO₂CH₂CH₃), 2,2-difluoroethyl methyl sulfone (CHF₂CH₂SO₂CH₃), 2,2-difluoroethyl ethyl sulfone (CHF₂CH₂SO₂CH₂CH₃), 2,2-difluoroethyl isopropyl sulfone

(CHF₂CH₂SO₂CH(CH₃)₂), and bis(2,2-difluoroethyl) sulfone (CHF₂CH₂)₂SO₂). In one embodiment, the fluorinated sulfone is difluoromethyl ethyl sulfone or bis(2,2-difluoroethyl) sulfone.

In the methods disclosed herein, a sulfur-containing reactant represented by the formula:

R¹SM (1 ) or

M₂S (2) wherein R¹ is a Ci to Cio alkyl group, optionally substituted with one or more ether oxygens, or fluoroalkyi group, optionally substituted with one or more ether oxygens, S is sulfur, and M is a cation selected from the group consisting of Na⁺, K⁺, Cs⁺, and a tetraalkylammonium cation, such as R₄N⁺, where R is CH₃, C₂H₅, or C₄H₉, is reacted with a fluorinated alkyl compound represented by the formula:

CF₂H-R²-X (3) wherein R² is either absent or a Ci to Cio alkylene group, optionally substituted with one or more ether oxygens, or fluoroalkylene group, optionally substituted with one or more ether oxygens, the carbon atom adjacent to X in R² is not fluorinated, and X is a leaving group selected from the group consisting of Br, CI, I, and -OSO₂R³ where R³ is aryl, F, CF₃, C₄F₉, or Ci to C10 alkyl, to give a fluorinated sulfide product. The fluorinated sulfide product can be recovered and used for various purposes, for example, to prepare a fluorinated sulfoxide by controlled oxidation, or it can be oxidized in the next step in the process disclosed herein to make the fluorinated sulfone product. Suitable sulfur- containing reactants for use in the methods disclosed herein include without limitation, sodium thiomethoxide, potassium thiomethoxide, cesium

thiomethoxide, tetramethyl ammonium thiomethoxide,

tetraethyl ammonium thiomethoxide, tetrabutyl ammonium thiomethoxide, sodium thioethoxide, potassium thioethoxide, cesium thioethoxide,

tetrabutylammonium thioethoxide, sodium 2-propanethiolate, potassium 2- propanethiolate, cesium 2-propanethiolate, tetrabutylammonium 2- propanethiolate, sodium sulfide, potassium sulfide, cesium sulfide, tetramethyl ammonium sulfide, tetraethyl ammonium sulfide, and tetrabutyl ammonium sulfide. Many of these sulfur-containing reactants are commercially available from companies such as Aldrich (Milwaukee, Wl). Alternatively, the sulfur- containing reactant can be generated in situ by adding a base such as sodium hydroxide or potassium hydroxide to a thiol represented by the formula R¹SH to produce the corresponding thiolate salt R¹SM, wherein R¹ is defined as above.

In some embodiments, the fluorinated alkyl compound used in the methods disclosed herein is a fluorinated alkyl halide represented by the formula: CHF₂-R²-X, wherein R² is defined as above, and X is CI, Br or I. In one embodiment, X is CI or Br. Examples of useful fluorinated alkyl halides include without limitation CHF₂CI, CHF₂Br, CHF₂-CH₂-Br, CHF₂-CH₂-CI, CHF₂-CH₂CH₂- Br, CHF₂-CH₂CH₂-CI, CHF₂-CH₂CH₂CH₂-Br, and CHF₂-CH₂CH₂CH₂-CI. In one particular embodiment, the fluorinated alkyl halide is CHF₂-CI. In another particular embodiment, the fluorinated alkyl halide is CHF₂-CH₂-Br. In another particular embodiment, the fluorinated alkyl halide is CHF₂-CH₂-CI. The fluorinated alkyl halides can be prepared using liquid phase or gas phase methods known in the art, for example using the methods described by Chen et al. (U.S. Patent Application Publication No.2002/0183569), Bolmer et al. (U.S. Patent No. 6,063,969), or Boyce et al. (U.S. Patent No. 5,910,616).

In the methods disclosed herein, the sulfur-containing reactant and the fluorinated alkyl compound, described above, are contacted for a time sufficient to form a fluorinated sulfide product. The reactants can be contacted in the absence of a solvent, in a reaction medium comprising a solvent, or in the gas phase.

In one embodiment, the sulfur-containing reactant and the fluorinated alkyl compound are contacted in a reaction medium comprising a solvent.

During the reaction, the temperature of the reaction medium is about 20 °C to about 300 °C, more particularly about 20 °C to about 200 °C, more particularly about 20 °C to about 150 °C, more particularly about 20 °C to about 80 °C, and more particularly, 20 °C to about 60 °C. The reaction medium can be agitated during the reaction using conventional means such as a magnetic stirrer, an overhead mixer, and the like. In various embodiments, the reaction pressure can be maintained at a level at which the solvent and reactants are kept in the liquid phase. A pressure between atmospheric and 1 ,000 psig is suitable for such purpose. Typically, the time sufficient to form a fluorinated sulfide product is about 5 hours to about 200 hours, more particularly about 5 hours to about 100 hours, and more particularly about 5 hours to about 50 hours. The reaction may occur in a batch or in a continuously fed reactor in which one or both reactants and optionally solvent are fed on a continuous basis. Product may accumulate in the reactor or be removed on a continuous basis.

Suitable solvents for use in the methods disclosed herein include without limitation, dimethylsulfoxide, toluene, tetrahydrofuran, ether,

dimethylformamide, dimethylacetamide, acetonitrile,

hexamethylphosphoramide, dichloromethane, 1 ,2-dimethoxyethane, N- methylpyrrolidinone, water, alcohols, ether-hexane mixtures, and tetrahydrofuran-hexanes mixtures. The fluorinated sulfide product formed in the reaction can also serve as the solvent. Therefore, the use of an additional solvent is optional. In one embodiment, the solvent is water. In another embodiment, the solvent is dimethylformamide. In another embodiment, the solvent is a 1 :1 volume mixture of hexanes and tetrahydrofuran.

The fluorinated sulfide product formed in the reaction may optionally be recovered from the reaction medium and purified using methods known in the art, for example, solvent extraction, column chromatography, or distillation methods such as vacuum distillation or spinning band distillation. In one embodiment, the fluorinated sulfide product is 2,2-difluoroethyl isopropyl sulfide.

Alternatively, the fluorinated sulfide product is oxidized to form a fluorinated sulfone product in a reaction medium comprising a solvent. The oxidization can be carried out in any suitable solvent, which is inert to oxidizing agents. Suitable solvents include without limitation, methanol,

dichloromethane, chloroform, benzene, toluene, chlorobenzene, and water. Suitable oxidizing agents include without limitation, m- chloroperoxybenzoic acid, peroxyphthalic acid, hydrogen peroxide (optionally in the presence of catalyst, such as TaCI₅, methyltrioxorhenium (CH₃ReO3), tungstic acid, or ortho-vanadates, etc.), hydrogen peroxide/acetic acid mixture, potassium monopersulfate, sodium periodate, t-butyl hypochlorite, sodium hypochlorite or sodium hypobromite, or any other oxidizing agents typically used for conversion of sulfides into sulfones and sulfoxides (for additional examples of oxidizing agents, see M. Hudlicky, Oxidations in Organic

Chemistry, ACS Monograph 186, Washington DC, 1990, p. 252-262.

The fluorinated sulfide is reacted with the oxidizing agent for a time sufficient to form the fluorinated sulfone product. During the reaction, the temperature of the reaction medium is about 0 °C to about 200 °C, more particularly about 0 °C to about 150 °C, more particularly about 0 °C to about 80 °C, and more particularly, about 0 °C to about 60 °C.

The reaction medium can be agitated during the reaction using conventional means such as a magnetic stirrer, an overhead mixer, and the like. In various embodiments, the reaction pressure can be maintained at a level at which the solvent and reactants are kept in the liquid phase. A pressure between atmospheric and 1 ,000 psig is suitable for such purpose. . Typically, the time sufficient to form the fluorinated sulfone product is about 1 hours to about 100 hours, more particularly about 1 hour to about 75 hours, and more particularly about 3 hours to about 48 hours. The oxidation reaction may occur in a batch or in a continuously fed reactor in which one or both reactants and optionally solvent are fed on a continuous basis. Product may accumulate in the reactor or be removed on a continuous basis.

The fluorinated sulfone product formed in the reaction may optionally be recovered from the reaction medium and purified using methods known in the art, for example, solvent extraction, column chromatography, recrystallization, sublimation, or distillation methods such as vacuum distillation or spinning band distillation. For best results when used as an electrolyte solvent in a lithium ion battery, as discussed below, it is desirable to purify the fluorinated sulfones to a purity level of at least about 99.9%, more particularly at least about 99.99%.

In one embodiment, a fluorinated sulfone prepared by a method disclosed herein is admixed with at least one electrolyte salt to form an electrolyte composition. Suitable electrolyte salts include without limitation ithium hexafluorophosphate (LiPF₆),

ithium tris(pentafluoroethyl)trifluorophosphate (LiPF3(C₂F₅)3)

ithium bis(trifluoromethanesulfonyl)imide,

ithium bis (perfluoroethanesulfonyl)imide,

ithium (fluorosulfonyl)(nonafluorobutanesulfonyl)imide,

ithium bis(fluorosulfonyl)imide

ithium tetrafluoroborate

ithium perchlorate

ithium hexafluoroarsenate

ithium trifluoromethanesulfonate lithium tris (trifluoromethanesulfonyl)methide,

lithium bis(oxalato)borate,

lithium difluoro(oxalato)borate,

Li₂Bi2Fi2_-xHx where x is equal to 0 to 8, and

mixtures of lithium fluoride and anion receptors such as B(OC₆F₅)₃.

Mixtures of two or more of these or comparable electrolyte salts may also be used. In one embodiment, the electrolyte salt is lithium

hexafluorophosphate. The electrolyte salt can be present in the electrolyte composition in an amount of about 0.2 to about 2.0 M, more particularly about 0.3 to about 1 .5 M, and more particularly about 0.5 to about 1 .2 M.

In one embodiment, the electrolyte composition comprises a fluorinated sulfone selected from the group consisting of difluoromethyl methyl sulfone, difluoromethyl ethyl sulfone, and bis(difluoroethyl) sulfone, and an electrolyte salt.

The electrolyte composition may also contain at least one co-solvent, which is added to the composition along with a fluorinated sulfone prepared by a method disclosed herein. Examples of suitable co-solvents include without limitation various carbonates such as ethylmethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, and fluoroethylene carbonate; and sulfones such as tetramethylene sulfone and ethyl methyl sulfone. For best results, it is desirable to use a co-solvent that is battery grade or has a purity level of at least about 99.9%, and more particularly at least about 99.99%. In one embodiment, the co-solvent is ethylene carbonate.

The fluorinated sulfones, prepared by the methods disclosed herein, and the co-solvent can be combined in various ratios to form a solvent mixture as used in the electrolyte composition, depending on the desired properties of the electrolyte composition. In one embodiment, the fluorinated sulfone comprises about 10% to about 90% by weight of the solvent mixture. In another embodiment, the fluorinated sulfone comprises about 40% to about 90% by weight of the solvent mixture. In another embodiment, the fluorinated sulfone comprises about 50% to about 80% by weight of the solvent mixture. In another embodiment, the fluorinated sulfone comprises about 60% to about 80% by weight of the solvent mixture. In another embodiment, the fluorinated sulfone comprises about 65% to about 75% by weight of the solvent mixture. In another embodiment, the fluorinated sulfone comprises about 70% by weight of the solvent mixture.

The electrolyte composition can be contacted with a cathode and an anode to form an electrochemical cell, such as a lithium ion battery. A cathode is the electrode of an electrochemical cell at which reduction occurs. In a galvanic cell, such as a battery, the cathode is the positively charged electrode. In a secondary (i.e. rechargeable) battery, the cathode is the electrode at which reduction occurs during discharge and oxidation occurs during charging. An anode is the electrode of an electrochemical cell at which oxidation occurs. In a galvanic cell, such as a battery, the anode is the negatively charged electrode. In a secondary (i.e. rechargeable) battery, the anode is the electrode at which oxidation occurs during discharge and reduction occurs during charging.

An electrochemical cell comprises a housing, an anode and a cathode disposed in the housing and in ionically conductive contact with one another, an electrolyte composition, as described above, providing an ionically conductive pathway between the anode and the cathode, and a porous or microporous separator between the anode and the cathode. The housing can be any suitable container to house the electrochemical cell components. The anode and the cathode can be made of any suitable conducting material depending on the type of electrochemical cell. Suitable examples of anode materials include without limitation lithium metal, lithium metal alloys, lithium titanate, aluminum, platinum, palladium, graphite, transition metal oxides, and lithiated tin oxide. Suitable examples of cathode materials include without limitation graphite, aluminum, platinum, palladium, electroactive transition metal oxides comprising lithium or sodium, indium tin oxide, and conducting polymers such as polypyrrole and polyvinylferrocene.

The porous separator serves to prevent short circuiting between the anode and the cathode. The porous separator typically consists of a single-ply or multi-ply sheet of a microporous polymer such as polyethylene,

polypropylene, or a combination thereof. The pore size of the porous separator is sufficiently large to permit transport of ions, but small enough to prevent contact of the anode and cathode either directly or from particle penetration or dendrites which can from on the anode and cathode.

In one embodiment, the electrochemical cell is a lithium ion battery, which is a type of rechargeable battery in which lithium ions move from the anode to the cathode during discharge, and from the cathode to the anode during charge. Suitable cathode materials for a lithium ion battery include without limitation electroactive transition metal oxides comprising lithium, such as LiCoO₂, LiNiO₂, LiMn₂O₄ or LiV₃O₈.

Various lithium composite oxides containing lithium and a transition metal may also be utilized as the cathode material. Suitable examples include composite oxides with the general formula LiMO₂ where M can be any metallic elements or combination of metallic elements such as cobalt, aluminum, chromium, manganese, nickel, iron, vanadium, magnesium, titanium, zirconium, niobium, molybdenum, copper, zinc, indium, strontium, lanthanum, and cesium. Additionally, the active material can be made of a material with the chemical formula LiMn_2-xM_x0 , where 0≤x<1 , or a material with the general formula LiMPO₄ where M can be any metallic element or combination of elements such as cobalt, aluminum, chromium, manganese, nickel, iron, vanadium,

magnesium, titanium, zirconium, niobium, molybdenum, copper, zinc, indium, strontium, lanthanum, and cesium. The cathode of the battery may include any of the active materials that may be held on an electrically conductive member that includes metal or another conductive element.

In one embodiment, the cathode in the lithium ion battery comprises a cathode active material exhibiting greater than 30 mAh/g capacity in the potential range greater than 4.35 V versus a Li/Li⁺ reference electrode. One example of such a cathode is a stabilized manganese cathode comprising a lithium-containing manganese composite oxide having a spinel structure as cathode active material. The lithium-containing manganese composite oxide in a cathode as used herein comprises oxides of the formula Li_xNiyM_zMn_2-y-zO -ci, wherein x is 0.03 to 1 .0; x changes in accordance with release and uptake of lithium ions and electrons during charge and discharge; y is 0.3 to 0.6; M comprises one or more of Cr, Fe, Co, Li, Al, Ga, Nb, Mo, Ti, Zr, Mg, Zn, V, and Cu; z is 0.01 to 0.18, and d is 0 to 0.3. In one embodiment, in the above formula, y is 0.38 to 0.48, z is 0.03 to 0.12, and d is 0 to 0.1 . In one

embodiment, in the above formula, M is one or more of Li, Cr, Fe, Co, and Ga. Stabilized manganese cathodes may also comprise spinel-layered composites which contain a manganese-containing spinel component and a lithium rich layered structure, as disclosed in U.S. Patent No. 7,303,840.

The cathode active material can be prepared using methods such as the hydroxide precursor method disclosed by Liu et al (J. Phys. Chem., C

13:15073-15079, 2009). In that method, hydroxide precursors are precipitated from a solution containing the required amounts of manganese, nickel and other desired metal(s) acetates by the addition of KOH. The resulting precipitate is oven-dried and then fired with the required amount of LiOH^»H₂0 at about 800 to about 950°C in oxygen for 3 to 24 hours, as described in detail in the examples herein. Alternatively, the cathode active material can be prepared using a solid phase reaction process or a sol-gel process as disclosed in U.S. Patent No. 5,738,957 (Amine).

The cathode, in which the cathode active material is contained, can be prepared by methods such as mixing an effective amount of the cathode active material (e.g. about 70 wt% to about 97 wt%), a polymer binder, such as polyvinyl idene difluoride, and conductive carbon in a suitable solvent, such as N-methylpyrrolidone, to generate a paste, which is then coated onto a current collector such as aluminum foil, and dried to form the cathode. The lithium ion battery disclosed herein further contains an anode, which comprises an anode active material that is capable of storing and releasing lithium ions. Examples of suitable anode active materials include without limitation lithium alloys such as lithium-aluminum alloy, lithium-lead alloy, lithium-silicon alloy, lithium-tin alloy and the like; carbon materials such as graphite and mesocarbon microbeads (MCMB); phosphorus-containing materials such as black phosphorus, MnP and C0P3; metal oxides such as SnO2, SnO and T1O2; and lithium titanates such as Li Ti₅Oi2 and LiTi₂O₄. In one embodiment, the anode active material is lithium titanate or graphite.

An anode can be made by a method similar to that described above for a cathode wherein, for example, a binder such as a vinyl fluoride-based copolymer is dissolved or dispersed in an organic solvent or water, which is then mixed with the active, conductive material to obtain a paste. The paste is coated onto a metal foil, preferably aluminum or copper foil, to be used as the current collector. The paste is dried, preferably with heat, so that the active mass is bonded to the current collector. Suitable anode active materials and anodes are available commercially from companies such as Hitachi NEI Inc. (Somerset, NJ), and Farasis Energy Inc. (Hayward, CA).

The lithium ion battery also contains a porous separator between the anode and cathode. The porous separator serves to prevent short circuiting between the anode and the cathode. The porous separator typically consists of a single-ply or multi-ply sheet of a microporous polymer such as

polyethylene, polypropylene, polyamide or polyimide, or a combination thereof. The pore size of the porous separator is sufficiently large to permit transport of ions to provide ionically conductive contact between the anode and cathode, but small enough to prevent contact of the anode and cathode either directly or from particle penetration or dendrites which can from on the anode and cathode. Examples of porous separators suitable for use herein are disclosed in U.S. Application SN 12/963,927 (filed 09 Dec 2010, U.S. Patent Application Publication No. 2012/0149852). The housing of the lithium ion battery can be any suitable container to house the lithium ion battery components described above. Such a container can be fabricated in the shape of small or large cylinder, a prismatic case or a pouch.

The lithium ion battery can be used for grid storage or as a power source in various electronically powered or assisted devices (an "Electronic Device") such as a transportation device (including a motor vehicle, automobile, truck, bus or airplane), a computer, a telecommunications device, a camera, a radio, or a power tool.

EXAMPLES

The subject matter disclosed herein is further illustrated by the following examples. These examples, while indicating some preferred embodiments, are given by way of illustration only, and should not be interpreted to exclude from the scope of the appended claims, and the equivalents thereof, subject matter that is not described in these examples.

The meaning of abbreviations used is as follows: "g" means gram(s), "mg" means milligram(s), " g" means microgram(s), "L" means liter(s), "ml_" means milliliter(s), "mol" means mole(s), "mmol" means millimole(s), "M" means molar concentration, "wt%" means percent by weight, "mol%" means mole percent, "cm" means centimeter(s), "mm" means millimeter(s), "ppm" means parts per million, "h" means hour(s), "min" means minute(s), "Hz" means hertz, "Pa" means pascal(s), "kPa" means kilopascal(s), "atm" means atmosphere(s), "rpm" means revolutions per minute, "psig" means pounds per square inch gauge, "NMR" means nuclear magnetic resonance spectroscopy, "mw" means molecular weight, "bp" means boiling point, "D" means density. A reference to "Aldrich" or a reference to "Sigma" means the said chemical or ingredient was obtained from Sigma-Aldrich, St. Louis, MO.

EXAMPLE 1

Preparation of Difluoromethyl Methyl Sulfide

Difluoromethyl methyl sulfide was prepared by reaction of sodium thiomethoxide with chlorodifluoromethane.

H₂0

CHF₂CI + CH₃SNa ► CHF₂SCH₃

60°C

A 21 wt% solution of aqueous sodium thiomethoxide (100 mL; 21 g NaSMe; 0.30 mol; mw=70.09; Aldrich 516686) was charged to a 600-mL stirred Parr autoclave under nitrogen. The autoclave was cooled in dry ice to about -5 °C and chlorodifluoromethane (> 99%; E.I. du Pont de Nemours and Co., Wilmington, DE; 30 g; 0.35 mol; mw=86.47; bp= -41 °C) was added from a tank on a balance via a steel pressure line. Stirring was started and the autoclave was warmed to 60 °C. The pressure initially increased to nearly 200 psig but then began to fall as the chlorodifluoromethane reacted; after 1 h at 60 °C the pressure was 100 psig. The reaction was allowed to stir at 60 °C for 16 h and then was cooled back to 26 °C. After this time, the pressure was 31 psig.

A condenser train was attached to an autoclave head valve with rubber tubing. The tubing from the autoclave led to a 100-mL round bottom flask with a wet-ice/acetone cold finger condenser, the outlet of which led to a 200-mL round bottom flask with a dry ice condenser which vented through a nitrogen bubbler. The first flask was cooled in wet ice/acetone (-15 °C) and the second flask was cooled in dry ice. The autoclave was first vented at room

temperature, and a few mL of unreacted chlorodifluoromethane condensed in the dry ice flask. The autoclave was then stirred and heated to 70 °C as the product, a mobile yellow-orange liquid, distilled out and was collected in the wet ice/acetone flask. A reported boiling point for difluoromethyl methyl sulfide is 41 °C (J. Amer. Chem. Soc. 82, 61 18, 1960). After half an hour distillation ceased, so a very slow sweep of nitrogen was introduced through a second autoclave head valve to sweep out the head space through the condenser train. The product was cooled in dry ice and the small amount of water which had codistilled froze. The liquid product was drawn off with a syringe to yield 24.5 g (about 80% yield) clear, yellow-orange difluoromethyl methyl sulfide. By NMR the product contained 3.8 mol% methanethiol and a trace of

chlorodifluoromethane. b e a

CHF2 S CH3

¹⁹F NMR (CDCI3): -95.92 ppm (d, J=56.1 Hz, 2F, c); -71 .40 (d, J=62.9Hz, 0.05F, CF₂CIH)

¹ H NMR (CDCI₃): 2.28 ppm (t, J=1 .OHz, 3H, a); 6.77 (t, J=56.1 Hz, 1 H, b); 1 .23 (q, J=7.4Hz,H, CH₃SH); 2.07 (d, J=7.4Hz, 0.12H, CH₃SH); 7.18 (t, J=62.9Hz,

0.025H, CF₂CIH)

EXAMPLE 2

Preparation of Difluoromethyl Methyl Sulfone

Difluoromethyl methyl sulfone was prepared by oxidation of

difluoromethyl methyl sulfide.

H₂0₂ ll

CHF₂SCH₃ ► CHF₂SCH₃

TaCIs «

Crude difluoromethyl methyl sulfide, prepared as described in Example

1 , (24 g; 0.24 mol; mw=98.1 1 ) was stirred with 5 g potassium hydroxide pellets for 50 min to remove methanethiol. The sulfide was then distilled into a 250-mL 3-neck flask containing a thermometer, dry ice condenser, dropping funnel and magnetic stirrer. The sulfide was diluted with 30 ml_ of methanol and tantalum pentachloride (0.40 g ; 1 .1 mmol; 0.45 mol%; mw=358.21 ; Strem Chemicals Inc,. Newbury, MA, 93-7324) was added with stirring. The solution was cooled in an ice-water bath to 3 °C and stirred as 75 ml_ cold 30 wt% hydrogen peroxide (0.73 mol; D=1 .1 1 ; Aldrich 216763) was added dropwise over 40 min. The internal temperature remained between 5-12 °C. After addition, the bath was removed and replaced with a water bath which was heated to 60 °C. The dry ice condenser was kept in place for the first hour of heating since there was initially some condensation and reflux while the bath temperature was still below 50 °C. The dry ice condenser was then replaced with a cold water condenser as the mixture was stirred at 60 °C for 25 h.

By NMR there was about 3% sulfoxide remaining, so 5 ml_ (0.06 mol) more 30% hydrogen peroxide was added all at once and the mixture was stirred at 60 °C for 24 h more. Then, 20 g of sodium sulfite (0.16 mol; mw=126.04) was added to destroy the remaining hydrogen peroxide and the mixture was extracted 3 times with 30 ml_ portions of dichloromethane. The extracts were combined and dried with magnesium sulfate and filtered. The filtrate was distilled at 1 atm (101 kPa) through a short-path still to remove about half the dichloromethane. The distillate appeared to have some water present which tested strongly positive with a peroxide test strip, indicating that not all the peroxide in the reaction was decomposed, so the pot solution (about 50 ml_) was filtered through a bed of activity 1 basic alumina. The filtrate still tested positive for peroxide, so about 100 mg of manganese dioxide was added to the pot, the dichloromethane was distilled off, and the pot was stirred in a 70 °C oil bath for 20 h to decompose any residual peroxide. The black mixture was filtered and the light tan filtrate (24.7 g) was distilled from a 80 °C oil bath through a 10-cm Vigreaux column. A clear, colorless fraction was collected (19 g; 39-41 °C/1 torr) which was 99.8% pure sulfone by NMR.

19

F NMR (CDCI3): -124.60 ppm (d of q, J 1 .7Hz, 52.7Hz, 2F, c)

¹ H NMR (CDCI3): 3.01 ppm (t, J=1 .5Hz, 3H, a); 6.26 (t, J=52.6Hz, 0.98H, b)

The sulfoxide intermediate has the following NMR peak assignments: 2.67 ppm (t, J=1 .6Hz, a'); 6.37 ppm (t, J=54.6Hz, b'); -124.26 (d of q, J=1 .7Hz, 55.0Hz, c')

EXAMPLE 3

Preparation of Difluoromethyl Ethyl Sulfide

Difluoromethyl ethyl sulfide was prepared by reaction of sodium thioethoxide with chlorodifluoromethane.

H₂0

HCF₂CI + CH₃CH₂SNa HCF SCH CH,

60°C

A solution containing sodium hydroxide (12.8 g; 0.32 mol; mw

and 0.4 g tetrabutyl-ammonium bromide in 125 ml_ of water was charged to a Parr 600-mL stirred autoclave under nitrogen. Ethanethiol (22 ml_; 18.5 g; 0.30 mol; mw=62.13; D=0.839; bp: 35 °C; Aldrich E3708) was added via syringe through a head port. The port was sealed and the mixture was warmed to 40 °C and stirred for 1 h. The pressure was initially 12 psig at 40 °C but dropped to 0 psig at 35 °C as the ethanethiol was converted to the sodium salt. The autoclave was cooled in dry ice and chlorodifluoromethane (37 g; 0.43 mol; mw=86.47; bp= -41 °C) was added from a tank on a balance via a steel pressure line. The autoclave was stirred and warmed to 60 °C with a heating mantle. The temperature briefly overshot to 77 °C before settling at 60 °C. After 5 h at 60 °C the pressure was 76 psig. The reaction was allowed to stand and cool to room temperature overnight. At 19 °C the pressure was 37 psig. The autoclave was vented through a bleach scrubber and then a slow nitrogen stream was run through the head space for 15 min to entrain ethanethiol vapor. The autoclave was opened and the product was poured into a separatory funnel. A clear, light brown liquid (28.7 g; 86%) was separated as a lower phase. The pH of the aqueous phase was neutral. By NMR the product contained 12 mol% ethanethiol and 4 mol% of chlorodifluoromethane. c d b a

CH F₂ S CH₂CH3

¹⁹F NMR (CDCIs): -93.04 ppm (d, J=56.5Hz, 2F, d); -71 .38 (d, J=63.3Hz, 0.10F, CF₂CIH)

¹ H NMR (CDCI₃): 1 .33 ppm (t, J=7.4Hz, 0.43H, CH₃CH₂SH); 1 .36 (t, J=7.5Hz, 3H, a); 1 .38 ppm (t, J= 7.3Hz, 0.15H, CH₃CH₂SH); 2.56 (quintet, J=7.3Hz, 0.27H, CH₃CH₂SH); 2.83 (q, J=7.5Hz, 2H, b); 6.82 (t, J=56.5Hz, 1 H, c); 7.18 (t, J=62.9Hz, 0.04H, CF₂CIH)

The crude product was stirred with 9 g of KOH pellets for 5 h and then was short-path distilled from a 1 10 °C oil bath to yield 23.3 g (bp=67-69 °C) of hazy, colorless difluoromethyl ethyl sulfide. Addition of activated 4A molecular sieves clarified the liquid; apparently the haze was water from the KOH. The NMR was very clean; there was a small water peak (8 mol%= 1 .3 wt%) at 1 .54 ppm.

¹ H NMR (CDCI₃): 1 .36 ppm (t, J=7.5Hz, 3H, a); 2.83 (q, J=7.5Hz, 2H, b); 6.82 (t, J=56.5Hz, 1 H, c) EXAMPLE 4

Preparation of Difluoromethyl Ethyl Sulfone

Difluoromethyl ethyl sulfone was prepared by oxidation of difluoromethyl ethyl sulfide.

H₂0₂ I?

HCF2SCH2CH3 ► HCF2SCH2CH3

TaCIs »

Difluoromethyl ethyl sulfide, prepared as described in Example 3, (20 g; 0.18 mol; mw=1 12.14) was placed in a 250-mL 3-neck flask containing a thermometer, condenser, dropping funnel and magnetic stirrer. The sulfide was diluted with 30 ml_ of methanol and tantalum pentachloride (0.30 g; 0.84 mmol; 0.47 mol%; mw=358.21 ; Strem Chemicals Inc., 93-7324) was added with stirring. The solution was cooled in an ice-water bath to 3 °C and stirred as 60 ml_ of cold 30 wt% hydrogen peroxide (0.58 mol; D=1 .1 1 ; Aldrich 216763) was added dropwise over 40 min. The internal temperature remained below 5 °C. After the addition, the ice bath was removed and replaced with an oil bath which was heated to 55 °C, and the solution was stirred for 64 h. A 2-mL sample of the hazy solution was extracted with 10 ml_ of dichloromethane. Roto- evaporation of the dichloromethane from a warm water bath

afforded clear liquid sulfone. By NMR there was about 1 % sulfoxide present.

O

c d ft b a II

c" cT tv a'

HCFo S CHOCHQ HCF₂^ CH2CH3

o

¹⁹F NMR (CDCI3): -123.22/123.17 ppm (d of d, J=19.97Hz, 52.5Hz, 2F, d) ¹ H NMR (CDCI₃): 1 .47 ppm (t, J=7.5Hz, 3H, a); 3.18 (q of t, J=0.9Hz, 7.5Hz, 2H, b); 6.18 (t, J=52.5Hz, 1 H, c); 6.31 (t, J=54.7Hz, 0.01 H, c') Sodium sulfite (10 g, 0.08 mol; mw=126.04) was added to destroy the remaining hydrogen peroxide and the mixture was stirred at 55 °C for 3 h.

Then, the mixture was cooled and extracted three times with 30 mL portions of dichloromethane. The extracts were combined, dried with magnesium sulfate overnight and filtered through a bed of 30 g activity 1 basic alumina. The alumina was washed with an additional 20 mL of dichloromethane. The filtrate was distilled at 1 atm (101 kPa) from a 90 °C oil bath to remove the

dichloromethane. Then, the product was distilled through a short-path still from a 100 °C oil bath at 9.5 torr (1 .3 kPa) in two clear, colorless fractions: #1 (1 .5 g; 68-69°C) and #2 (21 .5 g; 69.5°C).

#2 ¹H NMR (CDCIs): 1 .47 ppm (t, J=7.5Hz, 3H, a); 3.18 (q of t, J=0.9Hz, 7.5Hz, 2H, b); 6.16 (t, J=52.5Hz, 1 H, c); 6.30 (t, J=54.7Hz, 0.006H, c')

Fraction #2 was distilled through a 10-cm glass helices-packed Vigreaux column at 9.3 torr (1 .2 kPa) from a 120 °C oil bath. After a forerun of 40 drops (68-69.5°C), 1 1 .3 g of difluoromethyl ethyl sulfone was collected (69.5°C), leaving 7.6 g of liquid in the pot.

Difluoromethyl ethyl sulfone ¹ H NMR (CDCI₃): 6.16 (t, J=52.6Hz, 1 H, c); 6.29 (t, J=54.9Hz, 0.007H, c')

Pot ¹ H NMR (CDCI3): 6.14 (t, J=52.9Hz, 1 H, c); 6.27 (t, J=54.8Hz, 0.005H, c')

The distillate was very little enriched in the sulfoxide relative to the pot material even after over half of it had been distilled. Apparently the under- oxidized sulfoxide cannot be removed by simple distillation. All the fractions and pot material were combined into a single sample (21 .4 g), which was placed in a 250-mL 3-neck flask containing a thermometer, condenser, dropping funnel and magnetic stirrer. The sulfone was diluted with 25 ml_ of methanol and tantalum pentachloride (0.15 g; 0.42 mmol; mw=358.21 ; Strem Chemicals Inc., 93-7324) was added with stirring. The solution was stirred as 10 mL of cold 30 wt% hydrogen peroxide (0.10 mol; D=1 .1 1 ; Aldrich 216763) was added over 1 min. The mixture was then heated in a 70 °C oil bath and stirred for 45 h. The mixture was cooled and extracted three times with 30 mL portions of dichloromethane. The extracts were combined, dried with magnesium sulfate and filtered through a bed of 30 g activity 1 basic alumina and the alumina was washed with an additional 20 mL of dichloromethane. The filtrate was distilled at 1 atm (101 kPa) from a 90 °C oil bath to remove most of the dichloromethane. Then 0.1 g manganese dioxide was added to the pot to destroy traces of hydrogen peroxide and the mixture was stirred at 90 °C for 1 h.

The product was distilled through a 10-cm glass helices-packed Vigreaux column at 12.9 torr (1 .3 kPa) from a 120 °C oil bath. A forerun (1 .1 g; 73-74°C) was rejected; then difluoromethyl ethyl sulfone was collected (13.6 g; 74-75°C), leaving 3.2 g of liquid in the pot.

Difluoromethyl ethyl sulfone ¹ H NMR (CDCI₃): 1 .47 ppm (t, J=7.5Hz, 3H, a); 3.18 (q of t, J=1 .0Hz, 7.6Hz, 2H, b); 6.16 (t, J= 52.7Hz, 1 H). There was no sulfoxide apparent even at high gain. By gas chromatography-mass

spectrometry the product was 99.94% pure.

EXAMPLE 5

Preparation of 2,2-Difluoroethyl Methyl Sulfide

2,2-Difluoroethyl methyl sulfide was prepared by reaction of sodium thiomethoxide with 2-bromo-1 ,1 -difluoroethane.

To 230 g (689 mmol) of a 21 wt% solution of sodium thiomethoxide in water (Aldrich) was added 105 g (724 mmol) of 2-bromo-1 ,1 -difluoroethane. The mixture was heated at 65 °C for a total of 10 h to give an essentially quantitative yield of 2,2-difluoroethyl methyl sulfide.

¹ H NMR (methanol-c/₄) δ 5.99 (tt, ³J_HH = 4.3 Hz, ²J_HF = 56.6 Hz, 1 H), 2.87 (dt, ³JHH = 4.3 Hz, ³J_HF = 16.2 Hz, 2H), 2.17 (s, 3H). ¹⁹F NMR (methanol-c/₄) δ -1 15.03 (dt, ²J_HF = 56.6 Hz, ³J_HF = 16.2 Hz).

EXAMPLE 6

Preparation of 2,2-Difluoroethyl Methyl Sulfone 2,2-Difluoroethyl methyl sulfone (CAS 1214268-07-1 ) was prepared by oxidation of 2,2-difluoroethyl methyl sulfide.

To a solution of 10.0 g (89.2 mmol) of 2,2-difluoroethyl methyl sulfide, prepared as described in Example 5, dissolved in 80 ml_ of methanol and chilled to 10 °C were added 638 mg (1 .78 mmol) of tantalum pentachloride (Strem Chemicals Inc.), followed by 46 ml_ (446 mmol) of 30% aqueous hydrogen peroxide, added dropwise over 40 min. The solution was warmed to room temperature and then heated to 45 °C for 3.5 h. ¹ H and ¹⁹F NMR indicated complete conversion of the sulfide to the sulfone. The reaction mixture was filtered, concentrated under reduced pressure and chilled to 0 °C. The precipitate formed was recovered by filtration and dissolved in 15 mL of dichloromethane. The resulting solution was stirred over 8.1 g of sodium sulfite for 30 min, filtered, combined with 15 mL of hexane and chilled in a freezer. The resulting precipitate was collected by filtration and dissolved in 1 :1 diethyl ether-hexanes. The resulting solution was chilled in a freezer. The resulting precipitate was collected by filtration and dried under high vacuum to give 9.48 g (74%) of 2,2-difluoroethyl methyl sulfone.

¹ H NMR (methanol-c/₄) δ 6.30 (tt, ³J_HH = 4.6 Hz, ²J_HF = 54.8 Hz, 1 H), 3.86 (dt, ³JHH = 4.6 Hz, ³J_HF = 14.7 Hz, 2H), 3.08 (s, 3H). ¹⁹F NMR (methanol-c/₄) δ -1 17.73 (dt, ²J_HF = 54.8 Hz, ³J_HF = 14.7 Hz). EXAMPLE 7

Preparation of 2,2-Difluoroethyl Isopropyl Sulfide 2,2-Difluoroethyl isopropyl sulfide was prepared by reaction of sodium 2- propanethiolate with 2-bromo-1 ,1 -difluoroethane.

To 53.58 g (344 mmol) of 25.7 wt% aqueous sodium hydroxide were added dropwise 26.00 g (341 mmol) of 2-propanethiol (Aldrich) followed by 52.00 g (359 mmol) of 2-bromo-1 ,1 -difluoroethane. After the resulting mixture had been heated at 65 °C for 22 h, the lower, aqueous liquid layer was separated from the upper liquid layer, which contained 2,2-difluoroethyl isopropyl sulfide of sufficient purity to be used in the reaction step described in Example 8 to form 2,2-difluoroethyl isopropyl sulfone.

2,2-Difluoroethyl isopropyl sulfide: ¹H NMR (methanol-c/₄) δ 5.93 (tt, ³J_HH = 4.4 Hz, ²J_HF = 56.8 Hz, 1 H), 3.04 (hept, ³J_HH = 6.7 Hz, 1 H), 2.91 (dt, ³J_HH = 4.4 Hz, ³JHF = 16.2 Hz, 2H), 1 .26 (d, ³J_HH = 6.7 Hz, 6H). ¹⁹F NMR (methanol-c/₄) δ - 1 15.10 (dt, ²J_HF = 56.8 Hz, ³J_HF = 16.2 Hz).

EXAMPLE 8

Preparation of 2,2-Difluoroethyl Isopropyl Sulfone 2,2-Difluoroethyl isopropyl sulfone (CAS 1401527-63-6) was prepared by oxidation of 2,2- difluoroethyl isopropyl sulfide.

To a solution of 47.95 g (342 mmol) of 2,2-difluoroethyl isopropyl sulfide, prepared as described in Example 7, dissolved in 175 mL of methanol was added 0.61 g (1 .7 mmol) of tantalum pentachloride. The mixture was chilled to 3 °C, and 175 mL of 30 wt% H2O2 was added dropwise, keeping the internal temperature below 10 °C. The mixture was allowed to warm slowly to room temperature and then was heated at 45 °C for 5 h. The reaction mixture was concentrated by rotary evaporation, and the lower, organic layer was separated from the upper, aqueous layer. The organic layer was washed with 25 mL of water, dried over sodium sulfate, and distilled under reduced pressure (boiling point 68-70 "C/1 -2 torr) to give 37.28 g (63%) of 2,2-difluoroethyl isopropyl sulfone.

¹ H NMR (DMSO-c/e) δ 6.41 (tt, ³J_HH = 4.5 Hz, ²J_HF = 54.6 Hz, 1 H), 3.97 (dt, ³J_HH = 4.5 Hz, ³J_HF = 15.4 Hz, 2H), 3.30 (hept, ³J_HH = 6.8 Hz, 1 H), 1 .26 (d, ³J_HH = 6.8 Hz, 6H). ¹⁹F NMR (DMSO-c/₆) δ -1 14.37 (dt, ²J_HF = 54.6 Hz, ³J_HF = 15.4 Hz).

EXAMPLE 9

Preparation of Bis(difluoroethyl) Sulfide

Bis(difluoroethyl) sulfide was prepared by the reaction of sodium sulfide with 2-bromo-1 ,1 -difluoroethane.

Na₂S 3H₂O (76 g, Aldrich, 99%,) was dissolved in 200 mL of

dimethylformamide (DMF) and 40 g of HCF₂CH₂Br (99%, DuPont) was slowly added to the agitated solution. The addition was exothermic and the internal temperature of the reaction mixture rose to 65 °C. The reaction mixture was allowed to cool down to ambient temperature and was agitated for 16 h. Then, the reaction mixture was diluted with 500 mL of water and extracted with petroleum ether (twice withl 00 mL portions). The combined organic layer was washed with water to remove residual DMF and was dried over MgSO₄. The solvent was distilled out and the residue was distilled at atmospheric pressure to give 22 g of a fraction with bp=139-140 °C. According to NMR analysis, the isolated material was (HCF₂CH₂)₂S of 96% purity, contaminated by

approximately 4 % of HCF₂CH₂Br. Calculated yield of (HCF₂CH₂)₂S was 50%. ¹ H NMR (CDCIs): 2.94(2H, td, J=15.6, 4.5 Hz), 5.90 (1 H, tt, J=56.7, 5.0Hz) ppm; ¹⁹F NMR (CDCI3): -1 16.68 (tt, J=56.7, 15.6Hz) ppm.

EXAMPLE 10

Preparation of Bis(difluoroethyl) Sulfone

Bis(difluoroethyl) sulfone was prepared by oxidation of bis(difluoroethyl) sulfide. m-Chloro peroxybenzoic acid (MCPBA, 40g, 65%, Aldrich) was dissolved in 100 mL of dichloromethane. The solution was cooled down to 10 °C and 22 g of (HCF₂CH₂)2S, prepared as described in Example 9, was slowly added to the reaction mixture at 10-15 °C. The reaction mixture was warmed up to ambient temperature and was agitated for 2 days. Another portion (16 g) of MCPBA was added to the reaction mixture and agitation was continued for 24 h. Next morning the reaction mixture was filtered, and the filtrate was washed with a 1 .0 N solution of Na₂S₂O3 (three times with 200 mL portions) and saturated solution of NaHCO₃ (200 mL). The organic layer was separated, dried over MgSO₄, and the solvent was removed under reduced pressure. The residue (15 g) was distilled under vacuum to give 9.2 g of (HCF₂CH₂)2SO2, bp 60.5-63.5 °C/1 mm Hg, purity 95%. The NMR analysis of the isolated material revealed the presence of approximately 5 % of CFH=CHSO2CH₂CF₂H.

(HCF₂CH₂)₂SO₂:

1 H NMR (CDCIs): 3.63 (2H, td, J=13.5, 4.7 Hz), 6.22 (1 H, tt, J=55.7, 5.1 Hz) ppm;

¹⁹F NMR (CDCI3): -1 16.00 (tt, J=55.7, 13.5Hz) ppm.

CFH=CHSO₂CH₂CF₂H

1 H NMR (CDCI3): 3.63 (2H, td, J=13.5, 4.7 Hz), 6.22 (1 H, tt, J=54.7, 5.1 Hz), 6.38 (1 H,t, J=1 1 .3 Hz), 7.51 (1 H, dd, J=77.5, 1 1 .5 Hz) ppm;

1⁹F NMR (CDCI3): -104.84 (1 H, dd, J=77.5, 12.5), 1 15.75 (tt, J=54.7, 15.5Hz) ppm

Claims

CLAIMS What is claimed is:

1 . A method of preparing a fluorinated sulfone comprising the steps of:

(a) providing a sulfur-containing reactant represented by the formula:

R¹SM (1 ) or

(b) providing a fluorinated alkyl compound represented by the formula:

group, optionally substituted with one or more ether oxygens, the carbon atom adjacent to X in R² is not fluorinated. and X is a leaving group selected from the group consisting of Br, CI, I, and

-OSO₂R³ where R³ is aryl, F, CF₃, C₄F₉, or Ci to (_½ alkyl;

(e) optionally recovering the fluorinated sulfone product.

2. The method of claim 1 , wherein the contacting of step (c) is done in a reaction medium comprising a solvent.

3. The method of claim 2, wherein the solvent is selected from the group consisting of dimethylsulfoxide, toluene, tetrahydrofuran, ether,

dimethylformamide, dimethylacetamide, acetonitrile,

hexamethylphosphoramide, dichloromethane, 1 ,2-dimethoxyethane, N- methylpyrrolidinone, water, alcohols, ether-hexane mixtures, and

tetrahydrofuran-hexanes mixtures.

4. The method of claim 3, wherein the solvent is water.

5. The method of claim 1 , wherein the sulfur-containing reactant is selected from the group consisting of sodium thiomethoxide, potassium thiomethoxide, cesium thiomethoxide, tetramethyl ammonium thiomethoxide, tetraethyl ammonium thiomethoxide, tetrabutyl ammonium thiomethoxide, sodium thioethoxide, potassium thioethoxide, cesium thioethoxide,

tetrabutylammonium thioethoxide, sodium 2-propanethiolate, potassium 2- propanethiolate, cesium 2-propanethiolate, tetrabutylammonium 2- propanethiolate, sodium sulfide, potassium sulfide, cesium sulfide, tetramethyl ammonium sulfide, tetraethyl ammonium sulfide, and tetrabutyl ammonium sulfide.

6. The method of claim 1 , wherein the fluorinated alkyl compound is a fluorinated alkyl halide.

7. The method of claim 6, wherein the fluorinated alkyl halide is selected from the group consisting of CHF₂CI, CHF₂Br, CHF₂-CH₂-Br, CHF₂-CH₂-CI, CHF₂-CH₂CH₂-Br, CHF₂-CH₂CH₂-CI, CHF₂-CH₂CH₂CH₂-Br, and CHF₂- CH₂CH₂CH₂-CI.

8. The method of claim 7, wherein the fluorinated alkyl halide is CHF₂CI, CHF₂-CH₂-Br or CHF₂-CH₂-CI.

9. The method of claim 1 , wherein the fluorinated sulfone product comprises a fluorinated sulfone selected from the group consisting of

difluoromethyl methyl sulfone, difluoromethyl ethyl sulfone, 2,2-difluoroethyl methyl sulfone, 2,2-difluoroethyl ethyl sulfone, 2,2-difluoroethyl isopropyl sulfone, and bis(2,2-difluoroethyl) sulfone.

10. The method of claim 1 , wherein the oxidizing of step (d) is done by contacting the fluorinated sulfide product with an oxidizing agent selected from the group consisting of hydrogen peroxide, m-chloro peroxybenzoic acid, peroxyphthalic acid, hydrogen peroxide/acetic acid mixture, potassium monopersulfate, sodium periodate, t-butylhypochlorite, sodium hypochlorite and sodium hypobromite, for a time sufficient to form the fluorinated sulfone product.

1 1 . The method of claim 1 , wherein the sulfur-containing reactant represented by the formula R¹SM is formed by addition of a base to a thiol represented by the formual R¹SH.

12. A method of preparing a fluorinated sulfide comprising the steps of: (a) providing a sulfur-containing reactant represented by the formula:

R¹SM (1 ) or

(b) providing a fluorinated alkyl compound represented by the formula: CF₂H-R²-X (3) wherein R² is either absent or a Ci to C₁0 alkylene group, optionally substituted with one or more ether oxygens, or fluoroalkylene

-OSO2R³ where R³ is aryl, F, CF₃, C₄F₉, or Ci to C10 alkyl;

(d) optionally, recovering the fluorinated sulfide product.

13. An electrolyte composition comprising:

(a) a fluorinated sulfone selected from the group consisting of

difluoromethyl methyl sulfone, difluoromethyl ethyl sulfone, and bis(difluoroethyl) sulfone; and

(b) at least one electrolyte salt.

14. The electrolyte composition of claim 13 further comprising at least one co-solvent.

15. The electrolyte composition of claim 14, wherein the at least one co- solvent is selected from the group consisting of ethylmethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, fluoroethylene carbonate, tetramethylene sulfone, and ethyl methyl sulfone.

16. A fluorinated sulfone selected from the group consisting of difluoromethyl ethyl sulfone and bis(2,2-difluoroethyl) sulfone.

17. A fluorinated sulfide, wherein the fluorinated sulfide is 2,2- difluoroethyl isopropyl sulfide.