Non-aromatic asymmetric mono(2-cyanoethyl)triorganophosphate salt, its synthesis process and uses

Abstract

The present invention relates to a non-aromatic asymmetric mono(2-cyanoethyl)triorganophosphonium salt, its synthesis process and its use as an electrolyte compound, as a lubricant and lubricant additive, as a gas capture agent, as a solvent for catalysis and as a surface modification agent by Chemie Click.

Description

Title of the invention: NON-AROMATIC ASYMMETRIC MONO(2-CYANOETHYL)TRIORGANOPHOSPHONIUM SALT, ITS SYNTHESIS PROCESS AND ITS USES

[0001] The present invention relates to a non-aromatic asymmetric mono(2-cyanoethyl)triorganophosphonium salt, its synthesis process, and its use as an electrolyte compound, as a lubricant and lubricant additive, as a gas-capturing agent, as a solvent for catalysis, and as a surface-modifying agent by Click Chemistry. Field of the invention

[0002] The synthesis of ionic compounds derived from tris(2-cyanoethyl)phosphine leads to the formation of compounds belonging to the family of phosphonium salts substituted by a single chain (2-cyanoethyl) and three different non-aromatic substituents.

[0003] The prior art describes a current synthetic technology that involves the alkylation of an asymmetric triorganophosphine with a (2-cyanoethyl) chain. This synthesis uses a non-aromatic triorganophosphine that can be flammable, toxic, and is particularly sensitive to oxidation by air.

[0004] Air-Stable Trialkylphosphonium Salts: Simple, Practical, and Versatile Replacements for Air-Sensitive Trialkylphosphines. Applications in Stoichiometric and Catalytic Processes. Org. Lett. 2001, 3, 4295-4298 describes a process that obtains a mixture of by-products that are difficult to separate from the desired product.

[0005] Vlâd, G.; Richter, FU; Horvâth, IT Synthesis of Fluorous Trialkyl Phosphines with the Complete Exclusion of PH3. Tetrahedron Letters 2005, 46 (49), 8605-8608 describes a synthesis from phosphorus trihydride PH3 (toxic, flammable and extremely sensitive to oxidation) or phosphorus trichloride PC13 and this leads to a mixture of primary, secondary and tertiary phosphines that are difficult to control.

[0006] Current synthetic processes do not allow for the easy obtaining of this asymmetric triorganophosphine precursor.

[0007] Current synthesis processes do not allow the elimination of traces of phosphine oxides and phosphorus by-products, which results in poor purity of the synthesized product.

[0008] For these reasons, state-of-the-art synthesis processes are not compatible with industrial-scale manufacturing.

[0009] Moreover, prior art tris(2-cyanoethyl)phosphonium are phosphonium salts containing a single 2-cyanoethyl chain and three identical non-aromatic substituents.

[0010] DE102008021271 describes a mono(2-cyanoethyl)trialkylphosphonium salt thus having three identical substituents.

[0011] There is a real need for a new family of asymmetric mono(2-cyanoethyl)triorganophosphonium having different non-aromatic substituents and for a synthesis process enabling the production of high-purity products compatible with industrial scale. Summary of the invention

[0012] The invention relates to a new family of phosphonium salts of formula (I)

[0013] [Chem.l] 0)

[0014] in which

[0015] X is selected from fluoroalkyl phosphates, fluoroalkyl phosphinates, fluoroalkyl phosphonates, acetates, triflates, imides, amides, methanides, borates, phosphates, sulfonimides or aluminates;

[0016] RI, R2 and R3 are different from each other and independently chosen from among a C1-C20 alkyl, a C3-C6 cycloalkyl, a C2-C20 alkenyl, a C5-C8 cycloalkenyl, a C2-C20 alkynyl, a vinylbenzyl group; wherein the hydrogen atoms may be substituted by a fluorine, a -CF3, an ether, an alkyl group, a fluorinated alkyl group, a silyl group, a siloxy group, a sulfoxide group, a nitrile group, a thioether group or combinations thereof; provided that RI, R2 and R3 are different from a CH2-CH2-CN chain.

[0017] The invention also relates to a dimer of (2-cyanoethyl)phosphonium salt, as well as the process for synthesizing this family of compounds and the use of this family of compounds as an electrolyte compound, as a lubricant additive, as a lubricant, as a gas-capturing agent, as a catalytic solvent, and as a surface-modifying agent by Click Chemistry. Advantages of the invention

[0018] The invention proposes a new family of (2-cyanoethyl)phosphonium salts comprising a single (2-cyanoethyl) chain. These compounds have the advantage of being of high purity.

[0019] Phosphonium salts comprising a single (2-cyanoethyl) chain are of great interest. Indeed, the dipole moment and the dielectric constant of the ionic liquid of these compounds are increased compared to phosphonium salts lacking a nitrile group. The presence of a (2-cyanoethyl) chain allows for better desolvation of lithium ions as well as strong interaction with surfaces, making them suitable for surface grafting. These new salts are asymmetric, which gives them a low crystallization point and therefore makes them compatible with applications over a wider temperature range. Furthermore, having only one (2-cyanoethyl) chain and three non-aromatic substituents results in low-viscosity compounds.

[0020] Compared to their ammonium counterparts, the softer phosphorus atom allows a different interaction with surfaces and bis(trifluoromethanesulfonyl)imide (FSI) salts have lower melting points.

[0021] The method according to the invention has several advantages.

[0022] Firstly, the solvents used are products with low toxicity and are safe for the environment because they are described as "green".

[0023] Secondly, the synthetic precursors are inexpensive and stable in air and the synthetic intermediates are of low toxicity.

[0024] Thirdly, the reactions implemented are not very sensitive to oxygen.

[0025] Fourth, the synthesis process allows for the independent selection of the three non-aromatic organic groups that replace the (2-cyanoethyl)triorganophosphonium salt.

[0026] Fifth, the synthesis process makes it possible to obtain high-purity (2-cyanoethyl)triorganophosphonium salts.

[0027] Sixth, the process allows for an industrializable synthesis route. DETAILED DESCRIPTION OF THE INVENTION

[0028] A first object of the invention relates to a new family of phosphonium salts of formula (I)

[0029] [Chem.l]

[0030] in which

[0031] X is selected from fluoroalkyl phosphates, fluoroalkyl phosphinates, fluoroalkyl phosphonates, acetates, triflates, imides, amides, methanides, borates, phosphates, sulfonimides or aluminates;

[0032] RI, R2 and R3 are different from each other and independently chosen from among a C1-C20 alkyl, a C3-C6 cycloalkyl, a C2-C20 alkenyl, a C5-C8 cycloalkenyl, a C2-C20 alkynyl, a vinylbenzyl group; wherein the hydrogen atoms may be substituted by a fluorine, a -CF3, an ether, an alkyl group, a fluorinated alkyl group, a silyl group, a siloxy group, a sulfoxide group, a nitrile group, a thioether group or combinations thereof; provided that RI, R2 and R3 are different from a CH2-CH2-CN chain.

[0033] Hydrogen atoms can therefore be partially substituted as long as the molecule is stable.

[0034] The term "alkyl" refers to a saturated aliphatic radical, linear or branched, having the number of carbon atoms indicated. The alkyl fragment may have a linear or branched chain.

[0035] The term "alkenyl" designates an alkyl group, as defined above, comprising at least one C=C double bond.

[0036] The term "alkynyl" refers to an alkyl group, as defined above, comprising at least one C=C triple bond. The term "cycloalkyl" refers to a set of saturated or partially unsaturated monocyclic, bicyclic, bridged polycyclic, or spiro-rings. Monocyclic rings include, for example, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl rings.

[0037] In a more particularly preferred embodiment, RI is selected from a C1-C10 alkyl in which the hydrogen atoms can be substituted by a fluorine, a -CF3, an ether, an alkyl group, a perfluorinated alkyl group, a silyl group, a siloxy, a sulfoxide, a nitrile, a thioether or combinations thereof;

[0038] Even more preferably, RI is selected from a C1-C4 methyl or alkyl in which the hydrogen atoms can be substituted by a fluorine, a -CF3, an ether, an alkyl group, a perfluorinated alkyl group, a silyl group, a siloxy group, a sulfoxide group, a nitrile group, a thioether group or combinations thereof; and R2 is a Cl-CIO alkyl in which the hydrogen atoms can be substituted by a fluorine, a -CF3, an ether, an alkyl group, a perfluorinated alkyl group, a silyl group, a siloxy group, a sulfoxide group, a nitrile group, a thioether group or combinations thereof; and even more preferably, R2 is chosen from a methyl, an ethyl, a propyl, an iso-butyl, an n-butyl, or an allyl; and of which R3 is chosen preferably from an alkyl in Cl-CIO and even more preferably from an alkyl in C1-C4.

[0039] In a preferred embodiment, bis(oxalato)borate, difluorobis(oxalato)borate, acetate, N-ethyl-N-methyl-functionalized sulfonimide, (difluoromethanesulfonyl)(trifluoromethanesulfonyl)imide, (methanesulfonyl)(trifluoromethanesulfonyl)imide.

[0040] In an even more preferred embodiment, X is chosen from either the FSI or the TFSI.

[0041] The preferred embodiments regarding the choice of the anion X set out above can be combined with the preferred embodiments regarding the choice of the groups RI, R2 and R3 set out previously.

[0042] A second object of the invention is the phosphonium salt in the form of a dimer.

[0043] The phosphonium salt dimer is represented by formula (II),

[0044] [Chem.2] (II)

[0045] in which

[0046] Z is chosen from among the C1-C20 alkyl diradicals of the type -(CH2)n- which may comprise one or more ethers or which may comprise one or more chains of the type -CH2-Y-CH2- with Y=S, SO or SO2; preferably the alkyl diradical is an ethyl, propyl, butyl or pentyl diradical;

[0047] X is selected from fluoroalkyl phosphates, fluoroalkyl phosphinates, fluoroalkyl phosphonates, acetates, triflates, imides, amides, methanides, borates, phosphates, sulfonimides or aluminates;

[0048] R2 and R3 are different from each other and independently chosen from a C1-C20 alkyl, a C3-C6 cycloalkyl, a C2-C20 alkenyl, a C5-C8 cycloalkenyl, a C2-C20 alkynyl, a vinylbenzyl group; wherein the hydrogen atoms may be substituted by a fluorine, a -CF3, an ether, an alkyl group, a perfluorinated alkyl, a silyl, a siloxy, a sulfoxide, a nitrile, a thioether or combinations thereof; provided that R2 and R3 are different from a CH2-CH2-CN chain.

[0049] A third object of the invention is a method for synthesizing the family of phosphonium salts defined above.

[0050] When the salt is a monomer, the process comprises the following steps:

[0051] a) Mixing an alkali alkoxide solution with a tetrakis(hydroxymethyl)phosphonium chloride (THPC) solution or a tetrakis(hydroxymethyl)phosphonium sulfate (THPS) solution to obtain mixture A

[0052] b) Filtration of mixture A

[0053] c) Mixing the filtrate obtained in step b) with acrylonitrile

[0054] d) Filtration of the mixture obtained in step c) to obtain the precipitate formed of tris(2-cyanoethyl)phosphine (TCP)

[0055] e) Addition followed by mixing of an electrophile R3Y, of which Y may be a halide or an OTf (triflate) or an OTs (tosylate), and of which R3 is selected from a C1-C20 alkyl group, a C3-C6 cycloalkyl group, a C2-C20 alkenyl group, a C5-C8 cycloalkenyl group, a C2-C20 alkynyl group, a vinylbenzyl group; in which the hydrogen atoms may be substituted by a fluorine, a -CF3, an ether, an alkyl group, a fluorinated alkyl group, a silyl group, a siloxy group, a sulfoxide group, a nitrile group, a thioether group, or combinations thereof, to a TCP solution obtained in step d) in a solvent

[0056] f) Filtration followed by drying of the mixture obtained in step e) to obtain the precipitate formed of tris(2-cyanoethyl)phosphonium salt

[0057] g) Mixing a solution of alkali alkoxide with salt obtained in step f) in alcohol to obtain mixture B

[0058] h) Drying of mixture B

[0059] i) Addition followed by mixing of an electrophile R2Y, of which Y may be a halide or OTf (triflate) or OTs (tosylate), and of which R2 is selected from the group consisting of a C1-C20 alkyl, a C3-C6 cycloalkyl, a C2-C20 alkenyl, a C5-C8 cycloalkenyl, a C2-C20 alkynyl, a vinylbenzyl group; in which the hydrogen atoms may be substituted by a fluorine, a -CF3, an ether, an alkyl group, a fluorinated alkyl group, a silyl group, a siloxy group, a sulfoxide group, a nitrile group, a thioether group, or combinations thereof; to a solution of bis(2-cyanoethyl)phosphine obtained in step h) in a solvent

[0060] j) Filtration followed by drying of the mixture obtained in step i) to obtain the precipitate formed of bis(2-cyanoethyl)phosphonium salt

[0061] k) Mixing a solution of alkali alkoxide with salt obtained in step j) in alcohol to obtain mixture C

[0062] 1) Drying of mixture C

[0063] m) Addition followed by mixing of an electrophile R1Y, of which Y may be a halide or OTf (triflate) or OTs (tosylate), and of which RI is selected from the group consisting of a C1-C20 alkyl, a C3-C6 cycloalkyl, a C2-C20 alkenyl, a C5-C8 cycloalkenyl, a C2-C20 alkynyl, a vinylbenzyl group; in which the hydrogen atoms may be substituted by a fluorine, a -CF3, an ether, an alkyl group, a fluorinated alkyl group, a silyl group, a siloxy group, a sulfoxide group, a nitrile group, a thioether group, or combinations thereof; to a solution of (2-cyanoethyl)phosphine obtained in step 1) in a solvent

[0064] n) Filtration followed by drying of the mixture obtained in step m) to obtain the precipitate formed of (2-cyanoethyl)phosphonium salt

[0065] o) Ionic metathesis of the salt obtained in step n) in a solvent to obtain mixture D

[0066] p) Decantation, separation / filtration and drying of mixture D to obtain the (2-cyanoethyl)phosphonium salt PR1R2R3(2CN)X

[0067] When the salt is a dimer, the process comprises the following steps:

[0068] a) Mixing an alkali alkoxide solution with a tetrakis(hydroxymethyl)phosphonium chloride (THPC) solution or a tetrakis(hydroxymethyl)phosphonium sulfate (THPS) solution to obtain mixture A

[0069] b) Filtration of mixture A

[0070] c) Mixing the filtrate obtained in step b) with acrylonitrile

[0071] d) Filtration of the mixture obtained in step c) to obtain the precipitate formed of tris(2-cyanoethyl)phosphine (TCP)

[0072] e) Addition followed by mixing of an electrophile R3Y, of which Y may be a halide or an OTf (triflate) or an OTs (tosylate), and of which R3 is selected from a C1-C20 alkyl group, a C3-C6 cycloalkyl group, a C2-C20 alkenyl group, a C5-C8 cycloalkenyl group, a C2-C20 alkynyl group, or a vinylbenzyl group; wherein the hydrogen atoms may be substituted by a fluorine, a -CF3, an ether, an alkyl group, a fluorinated alkyl group, a silyl group, a siloxy group, a sulfoxide group, a nitrile group, a thioether group, or combinations thereof, to a TCP solution obtained in step d) in a solvent

[0073] f) Filtration followed by drying of the mixture obtained in step e) to obtain the precipitate formed of tris(2-cyanoethyl)phosphonium salt

[0074] g) Mixing a solution of alkali alkoxide with salt obtained in step f) in alcohol to obtain mixture B

[0075] h) Drying of mixture B

[0076] i) Addition followed by mixing of an electrophile R2Y of which Y may be a halide or OTf (triflate) or OTs (tosylate) and of which R2 is chosen from the group constituted by a C1-C20 alkyl, a C3-C6 cycloalkyl, a C2-C20 alkenyl, a C5-C8 cycloalkenyl, a C2-C20 alkynyl, a vinylbenzyl group; in which the hydrogen atoms may be substituted by a fluorine, a -CF3, an ether, an alkyl group, a fluorinated alkyl group, a silyl group, a siloxy group, a sulfoxide group, a nitrile group, a thioether group, or combinations thereof; to a solution of bis(2-cyanoethyl)phosphine obtained in step h) in a solvent

[0077] j) Filtration followed by drying of the mixture obtained in step i) to obtain the precipitate formed of bis(2-cyanoethyl)phosphonium salt

[0078] k) Mixing a solution of alkali alkoxide with salt obtained in step j) in alcohol to obtain mixture C

[0079] 1) Drying of mixture C

[0080] m) Addition followed by mixing of an electrophile YZY of which Y may be a halide or OTf (triflate) or OTs (tosylate) and of which Z is selected from C1-C20 alkyl diradicals of the type -(CH2)n- which may comprise one or more ethers or which may comprise one or more chains of the type -CH2-Y-CH2- with Y=S, SO or SO2; preferably the alkyl diradical is an ethyl, propyl, butyl or pentyl diradical; in which the hydrogen atoms may be substituted by a fluorine, a -CF3, an ether, an alkyl group, a fluorinated alkyl group, a silyl group, a siloxy group, a sulfoxide group, a nitrile group, a thioether group or combinations thereof; to a solution of (2-cyanoethyl)phosphine obtained in step 1) in a solvent

[0081] n) Filtration followed by drying of the mixture obtained in step m) to obtain the precipitate formed of (2-cyanoethyl)phosphonium dimer salt

[0082] o) Ionic metathesis of the salt obtained in step n) in a solvent to obtain mixture D

[0083] p) Decantation, separation / filtration and drying of mixture D to obtain the dimer salt (2-cyanoethyl)phosphonium (XPR2R3(2CN))2Z

[0084] A fourth object of the invention is the use of the family of phosphonium salts defined by formulas (I) and (II) as an electrolyte compound.

[0085] A fifth object of the invention is the use of the family of phosphonium salts defined by formulas (I) and (II) as a gas capture agent.

[0086] A sixth object of the invention is the use of the family of phosphonium salts defined by formulas (I) and (II) as a surface modification agent by Click Chemistry.

[0087] A seventh object of the invention is the use of the family of phosphonium salts defined by formulas (I) and (II) as a solvent for catalysis.

[0088] An eighth object of the invention is the use of the family of phosphonium salts defined by formulas (I) and (II) as a lubricant and as a lubricant additive. BRIEF DESCRIPTION OF FIGURES: General diagram of the synthesis process

[0089] [Fig.2] [Fig.2]: 1H NMR spectrum of (2- cyanoethyljethylmethylpropylphosphonium bis(fluorosulfonyl)imide P123(2CN)FSI

[0090] [Fig.3] [Fig.3]: 19F NMR spectrum of (2- cyanoethyljethylmethylpropylphosphonium bis(fluorosulfonyl)imide P123(2CN)FSI

[0091] [Fig.4] [Fig.4]: 31P NMR spectrum of (2- cyanoethyljethylmethylpropylphosphonium bis(fluorosulfonyl)imide P123(2CN)FSI

[0092] [Fig.5] [Fig.5]: Graph showing discharge capacities and efficiencies whole cell coulombics (LMNO / / Graphite) with and without compound (2-cyanoethyl)ethylmethylpropylphosphonium bis(fluorosulfonyl)imide P123(2CN)FSI at a C rate of 0.5 C between 2 V to 5 V relative to Li+ / Li at 25 °C.

[0093] EXAMPLE 1: (2-cyanoethyl)ethylmethylpropylphosphonium bis(fluorosulfonyl)imide P123(2CN)FSI

[0094] A NaOH solution is added to a THPC solution in a solvent while stirring. Acrylonitrile is then added. The reaction mixture is filtered to recover the precipitate formed (TCP). The TCP phosphine is dissolved in a solvent, and iodomethane is added while stirring. The resulting mixture is filtered and dried to recover the tris(2-cyanoethyl)methylphosphonium iodide salt. An alkali alkoxide solution is added to a suspension of tris(2-cyanoethyl)methylphosphonium iodide salt in alcohol while stirring. The reaction mixture is evaporated, yielding crude bis(2-cyanoethyl)methylphosphine. Bromoethane is added to a solution of this phosphine in a solvent while stirring. After filtration, the resulting solid is purified to obtain bis(2-cyanoethyl)ethylmethylphosphonium bromide salt.An alkali alkoxide solution is added to a suspension of bis(2-cyanoethyl)ethylmethylphosphonium bromide salt in alcohol while stirring. The mixture is evaporated under vacuum, yielding a crude (2-cyanoethyl)ethylmethylphosphine mixture. Iodopropane is added to a solution of this crude phosphine in a solvent while stirring. After filtration, the resulting solid is purified to obtain the iodide salt. of (2-cyanoethyl)ethylmethylpropylphosphonium. In a solvent, (2-cyanoethyl)ethyldimethylphosphonium iodide is added in suspension with LiFSI under stirring. The resulting liquid is purified to obtain the (2-cyanoethyl)ethylmethylpropylphosphonium bis(fluorosulfonyl)imide salt.

[0095] Figures 2, 3 and 4 show that (2-cyanoethyl)ethylmethylpropylphosphonium bis(fluorosulfonyl)imide P123(2CN)FSI was synthesized. FTIR (cm1) (pure) 2985, 2924, 2253, 1373, 1173, 1099, 829, 732, 567. 'H NMR (CD3CN, 500.11 MHz) d (ppm) 2.75 (dt, 2H, J = 13.1, 7.7 Hz), 2.51 (dt, 2H, J = 13.2, 7.7 Hz), 2.23 - 2.10 (m, 4H), 1.78 (d, 3H, J = 13.7 Hz), 1.63 - 1.53 (m, 2H), 1.20 (dt, 3H, J = 19.5, 7.7 Hz), 1.07 (td, 3H, J = 7.2, 1.3 Hz). 31P NMR (CD3CN, 202.45 MHz) d (ppm) 34.9. 19F NMR (CD3CN, 470.57 MHz) d (ppm) 51.42. Ionic purity (IC): 99.99%. Crystalline temperature < -80 °C.

[0096] EXAMPLE 2: Preparation of an LMNO / graphite battery with and without compound [P123(2CN) ESI] and charging and discharging of the battery

[0097] In a glove box under an inert atmosphere (Argon) with a water and O2 content of less than 1 ppm, the lithium salt LiFSI (0.936 g) is dissolved in the ionic liquid PYR13FSI (6.045 g) to obtain the desired concentration, a compound of (2-cyanoethyl)ethylmethylpropylphosphomum P123(2CN)FSI (0.154 g) is then added and mixed to obtain a homogeneous electrolyte solution.

[0098] Table 1 below groups together the different combinations of cathode / anode / electrolyte tested in battery.

[0099] [Tables 1] Positive Electrode - Capacitance Negative Electrode - Capacitance Electrolytes LMNO - 11mAh / cm² Graphite - 1.4 mAh / cm² IM LiFSI in PYR13FSI + 0.0628 mol / kg P123(2CN)FSI LMNO - 11mAh / cm² Graphite - 1.4 mAh / cm² IM LiFSI in PYR13FSI

[0100] Table 1: Battery-tested LMNO cathode / graphite anode / electrolyte combinations.

[0101] The batteries were tested in galvanostatic cycling from 2 to 5 V at a C rate of 0.5 C in a climatic chamber at 25 °C.

[0102] [Tables2] Electrolyte C-rate (Number of cycles) Charging capacity (mAh / g) Discharging capacity (mAh / g) Efficiency (%) IM LiFSI in PYR13FSI + 0.063 mol / kg P123(2CN)FSI 0.5 C (1st cycle) 105.85 105.34 99.51 IM LiFSI in PYR13FSI + 0.063 mol / kg P123(2CN)FSI 0.5 C (246th cycle) 98.48 98.17 99.68 IM LiFSI in PYR13FSI + 0.063 mol / kg P123(2CN)FSI 0.5 C (478th cycle) 89.09 88.80 99.68 IM LiFSI in PYR13FSI 0.5 C (1st cycle) 107.99 107.45 99.51 IM LiFSI in PYR13FSI 0.5 C (246th cycle) 93.64 93.33 99.67

[0103] Table 2: Characteristics of batteries with an LMNO / / Graphite system at 0.5 C with and without compound P123(2CN)FSI.

[0104] Table 2 and [Fig.5] show the discharge capacity as a function of the number of cycles of the two systems, with and without (2-cyanoethyl)ethylmethylpropylphosphonium salt compound.

[0105] In the electrolyte without the P123(2CN)FSI compound, the discharge capacity of the first cycle at a charge and discharge rate of 0.5 C is slightly higher than with the (2-cyanoethyl)ethylmethylpropylphosphonum compound (107.45 mAh / g and 105.34 mAh / g, respectively). However, with regard to cycleability, the capacity of the system containing the P123(2CN)FSI compound is more stable over the cycles. Indeed, considering the first 246 cycles, the capacity loss during discharge for the system without the P123(2CN)FSI compound is 13.14% compared to 6.81% for the system containing the (2-cyanoethyl)ethylmethylpropylphosphonum compound.

[0106] Capacity retention is better for the system containing the compound P123(2CN)FSI.

Claims

Demands

1. Salts of (2-cyanoethyl)phosphonium represented by formula (I): [Chem.1] X' Os in which X is selected from fluoroalkyl phosphates, fluoroalkyl phosphinates, fluoroalkyl phosphonates, acetates, triflates, imides, amides, methanides, borates, phosphates, sulfonimides or aluminates; R1, R2 and R3 are different from each other and independently selected from a C1-C20 alkyl, a C3-C6 cycloalkyl, a C2-C20 alkenyl, a C5-C8 cycloalkenyl, a C2-C20 alkynyl, a vinylbenzyl group; in which the hydrogen atoms can be substituted by a fluorine, a -CF3, an ether, an alkyl group, a fluorinated alkyl group, a silyl group, a siloxy group, a sulfoxide group, a nitrile group, a thioether group or combinations thereof; provided that RI, R2 and R3 are different from a CH2-ch2-cn chain.

2. Phosphonium salt according to claim 1 in which RI, R2 and R3 are different from each other and independently selected from a Cl-CIO alkyl in which the hydrogen atoms can be substituted by a fluorine, a -CF3, an ether, an alkyl group, a fluorinated alkyl group, a silyl group, a siloxy group, a sulfoxide group, a nitrile group, a thioether group or combinations thereof; provided that RI, R2 and R3 are different from a CH2-CH2-CN chain.

3. Phosphonium salt according to claim 2 in which RI, R2 and R3 are different from each other and selected from a C1-C4 methyl or alkyl group in which the hydrogen atoms may be substituted by a fluorine, a -CF3, an ether, an alkyl group, a fluorinated alkyl group, a silyl group, a siloxy group, a sulfoxide group, a nitrile group,

4.

5.

6.

7. a thioether group or their combinations; provided that RI, R2 and R3 are different from a CH2-CH2-CN chain. Phosphonium salt according to any one of Claims 1 to 3 in which the anion is chosen from bis(fluorosulfonyl)imide (FSI), bis(trifluoromethanesulfonyl)imide (TFSI), tetrafluoroborate, hexafluorophosphate, dicyanamide, triflate, 4,5-dicyano-2-(trifluoromethyl)imidazolate, fluorosulfonyl(trifluoromethanesulfonyl)imide, bis(oxalato)borate, difluorobis(oxalato)borate, acetate, N-ethyl-N-methyl-functionalized sulfonimide, (difluoromethanesulfonyl) (trifluoromethanesulfonyl)imide, (methanesulfonyl) (trifluoromethanesulfonyl)imide, (difluoromethanesulfonyl) (fluoromethanesulfonyl)imide, (methanesulfonyl) (fluoromethanesulfonyl)imide. Phosphonium salt according to claim 4 in which the anion X is selected from FSI or TFSI. Phosphonium salt according to any one of claims 1 to 5 wherein the (2-cyanoethyl)phosphonium salt is in the form of a dimer. A process for synthesizing a phosphonium salt as defined in any one of claims 1 to 5 comprising the following steps: a) Mixing an alkali alkoxide solution with a tetrakis(hydroxymethyl)phosphonium chloride (THPC) solution or a tetrakis(hydroxymethyl)phosphonium sulfate (THPS) solution to obtain mixture A; b) Filtering mixture A; c) Mixing the filtrate obtained in step b) with acrylonitrile; d) Filtering the mixture obtained in step c) to obtain the precipitate formed of tris(2-cyanoethyl)phosphine (TCP); e) Addition followed by mixing of an electrophile R3Y, of which Y may be a halide or an OTf (triflate) or an OTs (tosylate) and of which R3 is selected from a C1-C20 alkyl group, a C3-C6 cycloalkyl group, or a C2-C20 alkenyl group. a C5-C8 cycloalkenyl, a C2-C20 alkynyl, a vinylbenzyl group;in which the hydrogen atoms can be substituted by a fluorine, a -CF3, an ether, an alkyl group, a fluorinated alkyl group, a silyl group, a siloxy group, a sulfoxide group, a nitrile group, a thioether group or their derivatives; combinations to a TCP solution obtained in step d) in a solvent f) Filtration followed by drying of the mixture obtained in step e) to obtain the precipitate formed of tris(2-cyanoethyl)phosphonium salt. g) Mixture of an alkali alkoxide solution of the salt obtained in step f) in alcohol to obtain mixture B. h) Drying of mixture B (i) Addition followed by mixing of an electrophile R2Y, where Y may be a halide or OTf (triflate) or OTs (tosylate), and where R2 is selected from the group consisting of a C1-C20 alkyl, a C3-C6 cycloalkyl, a C2-C20 alkenyl, a C5-C8 cycloalkenyl, a C2-C20 alkynyl, a vinylbenzyl group; in which the hydrogen atoms may be substituted by a fluorine, a -CF3, an ether, an alkyl group, a fluorinated alkyl group, a silyl group, a siloxy group, a sulfoxide group, a nitrile group, a thioether group, or combinations thereof; to a solution of bis(2-cyanoethyl)phosphine obtained in step (h) in a solvent j) Filtration followed by drying of the mixture obtained in step i) to obtain the precipitate formed of bis(2-cyanoethyl)phosphonium salt. k) Mixing of an alkali alkoxide solution with the salt obtained in step j) in alcohol to obtain mixture C. 1) Drying of mixture C (m) Addition followed by mixing of an electrophile RI Y, where Y may be a halide or OTf (triflate) or OTs (tosylate), and where RI is selected from the group consisting of a C1-C20 alkyl, a C3-C6 cycloalkyl, a C2-C20 alkenyl, a C5-C8 cycloalkenyl, a C2-C20 alkynyl, a vinylbenzyl group; in which the hydrogen atoms may be substituted by a fluorine, a -CF3, an ether, an alkyl group, a fluorinated alkyl group, a silyl group, a siloxy group, a sulfoxide group, a nitrile group, a thioether group, or combinations thereof; to a solution of (2-cyanoethyl)phosphine obtained in step 1) in a solvent n) Filtration followed by drying of the mixture obtained in step m) to obtain the precipitate formed as the (2-cyanoethyl)phosphonium salt; o) Ionic metathesis of the salt obtained in step n) in a solvent to obtain mixture D

8.

9.

10.

11.

12. (p) Decantation, separation / filtration and drying of mixture D to obtain the (2-cyanoethyl)phosphonium salt PR1R2R3(2CN)X. Use of the phosphonium salt as defined in any one of claims 1 to 6 as an electrolyte compound. Use of the phosphonium salt as defined in any one of claims 1 to 6 as a gas capture agent. Use of the phosphonium salt as defined in any one of claims 1 to 6 as a surface modification agent by 'Click' chemistry. Use of the phosphonium salt as defined in any one of claims 1 to 6 as a solvent for catalysis. Use of the phosphonium salt as defined in any one of claims 1 to 6 as a lubricant additive or as a lubricant.

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