HK1163005B - Tricyanoborates - Google Patents

Description

Tricyanoborate

Technical Field

The invention relates to novel tricyanoborates, the use thereof and a method for the production thereof.

Background

The term "ionic liquid" is generally used to refer to salts that are liquid at temperatures below 100 ℃, in particular at room temperature. These liquid salts generally comprise an organic cation and an organic or inorganic anion.

The organic cation of the ionic liquid is typically a quaternary ammonium ion or a quaternary phosphonium ion or a cation of an aromatic base, typically a nitrogen containing base, which may be substituted by alkyl groups, halogen atoms or cyano groups and may also contain other heteroatoms such as phosphorus, sulphur or oxygen. Examples of customary organic cations are imidazolium, oxazolium, pyrazinium, pyrazolium, pyridazinium, pyrrolidinium, pyridinium, thiazolium and triazolium cations.

The typical anion in ionic liquids is AlCl₄ ^-、AsF₆ ^-、BF₄ ^-、Br^-、CF₃SO₃ ^-、(CF₃)₂PF₄ ^-、(CF₃)₃PF₃ ^-、(CF₃)₄PF₂ ^-、(CF₃)₅PF^-、(CF₃)₆P^-、Cl^-、CN^-、SCN^-、FeCl₃ ^-、NO₃ ^-、PF₆ ^-Pyruvate, acetate, oxalate or the tricyanomethane anion described in EP-A-1634867. In addition, WO2004/072089 and WO2007/093961 disclose the general formula [ BF ]_n(CN)_4-n]^-Wherein n is 0, 1, 2 or 3.

Ionic liquids have a range of interesting properties: typically, they are thermally stable, relatively non-flammable, and have very low vapor pressures. In addition, it has excellent solvent characteristics for a wide variety of organic and inorganic substances. Ionic liquids also have interesting electrochemical properties due to their ionic structure, such as electrical conductivity, which is often accompanied by high electrochemical stability. Therefore, there is a fundamental need for new ionic liquids with various properties, opening up further opportunities for their use.

Disclosure of Invention

It is an object of the present invention to provide novel stable compounds useful as ionic liquids or precursors to ionic liquids and methods for their preparation. These compounds should be able to be disposed of after use in an environmentally friendly manner.

This object is achieved by the tricyanoborate as claimed in claim 1, by its use as claimed in claim 12 and by its preparation as claimed in claims 13 and 14. Further preferred embodiments are the subject of the dependent claims.

The present invention relates to novel tricyanoborates of the general formula:

wherein R is¹Is C_1-6Alkyl radical, C_2-6Alkenyl radical, C_6-10An aryl group or a benzyl group,

x is oxygen or sulfur, and

Catⁿ⁺is a cation (where n is 1 or 2) selected from the group consisting of inorganic cations Mⁿ⁺And an organic cation Qⁿ⁺(wherein n is 1 or 2).

Here and hereinafter, the expression "C_1-nAlkyl "refers to any straight or branched chain alkyl group containing 1 to n carbon atoms. For example, the expression "C_1-6Alkyl "comprises the following groups: such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl (3-methylbutyl), neopentyl (2, 2-dimethylpropyl), hexyl and isohexyl (4-methylpentyl).

Here and hereinafter, the expression "C_2-nAlkenyl "means a carbon chain consisting of 2 to n carbon atoms and containing at least one double bond, wherein the carbon atoms are saturated with hydrogen atoms and the carbon chain is capable of branching. For example, the expression "C_2-4Alkenyl "comprises the following groups: such as vinyl, 1-methylvinyl, prop-1-enyl, prop-2-enyl, 2-methylprop-2-enyl and but-1, 3-dienyl.

Here and hereinafter, the expression "C_6-10Aryl "means having from 6 to 10 carbon atoms and may be substituted with one or more C_1-4Alkyl or C_1-4Alkoxy-substituted aryl. For example, "C_6-10Aryl "includes phenyl, benzyl, methylphenyl, methoxyphenyl, dimethylphenyl, ethylmethylphenyl, diethylphenyl, and naphthyl.

Preferred are tricyanoborates of formula I in which X is oxygen.

Also preferred is where R¹Is C_1-6Alkyl (R)¹Preferably methyl, ethyl or propyl, and more preferably methyl) tris of formula IA cyano borate.

In another preferred embodiment, the cation Catⁿ⁺Is selected from Li⁺、Na⁺、K⁺、Rb⁺、Cs⁺、NH₄ ⁺、Be²⁺、Mg²⁺、Ca²⁺、Sr²⁺And Ba²⁺Inorganic cation M of the groupⁿ⁺(wherein n is 1 or 2).

In a preferred embodiment, the cation Catⁿ⁺Is an organic cation Q containing at least one heteroatom selected from the group consisting of nitrogen, phosphorus, sulfur and oxygenⁿ⁺(wherein n is 1 or 2, preferably n is 1).

Particular preference is given to divalent organic cations Q²⁺Tricyanoborate of formula I (such as ethylenediamine).

It is further particularly preferred to have a monovalent organic cation Q⁺The tricyanoborate of the formula I, the monovalent organic cation Q⁺Selected from the group consisting of cations of the formula:

（a）(WR²R³R⁴R⁵)⁺wherein W is nitrogen or phosphorus, and

(i) wherein R is²To R⁴Independently is C_1-20Alkyl, and R⁵Is C_1-20Alkyl radical, C_3-10Cycloalkyl or C_6-10Aryl, wherein R²To R⁵Independently optionally containing one or more halogens, or

(ii) Wherein R is²And R³Together with W form a 5-to 7-membered ring, and R⁴And R⁵Independently is C_1-20Alkyl radical, wherein R⁴And R⁵Independently optionally containing one or more halogens, or

(iii) Wherein R is²And R³Or R⁴And R⁵In each case together with W form a 5-to 7-membered ring, or

（b）(XR⁶R⁷R⁸)⁺Wherein X is nitrogen, and R⁶And R⁷Form a ring together with X, wherein X is formally bonded to R via one single bond and one double bond⁶And R⁷And R is⁸Is C_1-20Alkyl radical, C_3-10Cycloalkyl or C_6-10Aryl, wherein R⁸Optionally containing one or more halogens, or

（c）(YR⁹R¹⁰R¹¹)⁺Wherein Y is sulfur, and

(i) wherein R is⁹And R¹⁰Independently is C_1-20Alkyl, and R¹¹Is C_1-20Alkyl radical, C_3-10Cycloalkyl or C_6-10Aryl, wherein R⁹To R¹¹Independently optionally containing one or more halogens, or

(ii) Wherein R is⁹And R¹⁰Together with Y form a 5-to 7-membered ring, and R¹¹Is C_1-20Alkyl radical, C_3-10Cycloalkyl or C_6-10Aryl, wherein R¹¹Optionally containing one or more halogens, or

（d）(ZR¹²R¹³)⁺Wherein Z is oxygen or sulfur, and R¹²And R¹³Form a ring together with Z, wherein Z is formally bonded to R via one single bond and one double bond¹²And R¹³And is and

wherein one or more than one is selected from the group consisting of C_1-20Alkyl radical, C_1-20Alkoxy radical, C_3-10Cycloalkyl radical, C_6-10A substituent of the group consisting of aryl, halogen and cyano being optionally bound to said substituent R²To R¹³Each ring formed wherein said C_1-20Alkyl radical, said C_1-20Alkoxy radical, said C_3-10Cycloalkyl and said C_6-10Aryl independently optionally contains one or more halogens, and

wherein the substituent R is defined by²To R¹³Each ring formed optionally contains one or two further substituted or unsubstituted heteroatoms selected from the group consisting of nitrogen, sulfur and oxygen, and/or is fused to another aromatic or non-aromatic 5-to 7-membered ring. Suitable substituents for heteroatoms are, for example, C_1-8An alkyl group.

Here and hereinafter, the expression "C_3-nCycloalkyl "refers to cycloalkyl groups having 3 to n carbon atoms. "C_3-10Cycloalkyl "represents, for example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl or cyclodecyl.

Here and hereinafter, the expression "C_1-nAlkoxy "refers to an unbranched or branched alkoxy group having 1 to n carbon atoms. "C_1-20Alkoxy "represents, for example, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, pentyloxy, 1, 4-dimethylpentyloxy, hexyloxy, heptyloxy, octyloxy, 1, 5-dimethylhexyloxy, nonyloxy, decyloxy, 4-ethyl-1, 5-dimethylhexyloxy, undecyloxy, dodecyloxy, tridecyloxy, tetradecyloxy or eicosyloxy.

Here and hereinafter, the expression "halogen" means fluorine, chlorine, bromine or iodine.

Particularly preferred are those in which the organic cation Q⁺A tricyanoborate of formula I selected from the group consisting of: organic ammonium, phosphonium, sulfonium, pyrrolidinium, pyrrolinium, pyrrolidinium, pyrazolium, imidazolium, triazolium, oxazolium, thiazolium, piperidinium, piperazinium, morpholinium, pyridinium, pyridazinium, pyrimidinium, pyrazinium, 1, 3-dioxolinium, pyrylium, and thiopyrylium cations.

Preferably, the organic cation Q⁺Selected from the group consisting of:

wherein R and R' are independently C_1-20Alkyl, preferably C_1-14Alkyl and more preferably C_1-8Alkyl, and m is an integer between 0 and 4. The substituents R and R' are preferably of different lengths.

More preferably, the organic cation Q⁺Selected from the group consisting of:

in another particularly preferred embodiment, the organic cation Q⁺Is an imidazolium cation, especially of the general formula

Wherein R and R' are independently C_1-20Alkyl, preferably C_1-14An alkyl group. In a most preferred embodiment, R is methyl and R' is ethyl.

In particular, the compound 1-ethyl-3-methylimidazolium tricyanomethoxyborate is claimed.

Tricyanoborates having organic cations are generally liquid at temperatures below 100 ℃, in particular at room temperature, and are therefore referred to as ionic liquids. Ionic liquids are extremely suitable for use as solvents for a variety of organic and inorganic substances due to their properties.

Accordingly, claimed are tricyanoborates of the formula I (I) ((II))Wherein R is¹Is C_1-6Alkyl radical, C_2-6Alkenyl radical, C_6-10Aryl or benzyl, X is oxygen or sulfur, and Catⁿ⁺Is an organic cation Qⁿ⁺(wherein n is 1 or 2, preferably n is 1)) as a polar aprotic solvent, optionally in admixture with one or more other ionic liquids, water or organic solvents.

Ionic liquids are suitable for a variety of applications: their use ranges from solvents in inorganic and organic synthesis to electrolytes and/or lubricants used as release agents and additives for hydraulic fluids. Thus, the range of specific requirements that an ionic liquid must meet to be suitable for a particular application is relatively broad. The ionic liquids of the present invention are particularly characterized by non-coordinating anions. In addition, it is halogen-free, so that it can be disposed of in an inexpensive and environmentally friendly manner, such as incineration, and its use and storage are simplified due to its low corrosivity towards metals.

The ionic liquids of the invention may be characterized by the selection of suitable substituents-X-R for the organic cation and the borate anion¹But is changed. Thus, for example, by changing the substituent-X-R of the borate anion¹And changing the organic cation and its substituents can strongly influence the melting point, thermal and electrochemical stability, viscosity, polarity and solubility in water or organic solvents.

Furthermore, the invention relates to the preparation of inorganic tricyanoborates of the formula I (wherein R is¹Is C_1-6Alkyl radical, C_2-6Alkenyl radical, C_6-10Aryl or benzyl, X is oxygen or sulfur, and Catⁿ⁺Is preferably selected from the group consisting of Li⁺、Na⁺、K⁺、Rb⁺、Cs⁺、NH₄ ⁺、Be²⁺、Mg²⁺、Ca²⁺、Sr²⁺And Ba²⁺Inorganic cation M of the groupⁿ⁺(wherein n is 1 or 2)) characterized in that

Make B (XR)¹)₃With cyano-tri-C_1-6Alkylsilanes (especially cyanogen)Trimethylsilyl (TMSCN)) at Mⁿ⁺(CN^-)_nIn the presence of a catalyst, wherein

R¹Is C_1-6Alkyl radical, C_2-6Alkenyl radical, C_6-10An aryl group or a benzyl group,

x is oxygen or sulfur, and

Mⁿ⁺is preferably selected from the group consisting of Li⁺、Na⁺、K⁺、Rb⁺、Cs⁺、NH₄ ⁺、Be²⁺、Mg²⁺、Ca²⁺、Sr²⁺And Ba²⁺Inorganic cations of the group (wherein n is 1 or 2).

Preferably B (XR)¹)₃And Mⁿ⁺(CN^-)_nIn a molar ratio of 0.8:1.0 to 1.2:1.0, in particular in a molar ratio of 0.9:1.0 to 1.1: 1.0. With B (XR)¹)₃Preferably, an excess of cyanotri-C is used_1-6Alkylsilanes, for example, in a molar ratio of from 1.5:1 to 10:1, in particular in a molar ratio of from 3:1 to 5: 1. The process for preparing the inorganic tricyanoborate is preferably carried out at a temperature of from 0 ℃ to 250 ℃, in particular at a temperature of from 50 ℃ to 100 ℃. The process for preparing the inorganic tricyanoborates is preferably carried out above the alkoxytri-C formed as by-product_1-6The boiling point of the alkylsilane.

The invention also relates to the preparation of the organic tricyanoborates of the formula I (wherein R is¹Is C_1-6Alkyl radical, C_2-6Alkenyl radical, C_6-10Aryl or benzyl, X is oxygen or sulfur, and Catⁿ⁺Is an organic cation Qⁿ⁺(wherein n is 1 or 2, preferably n is 1)) characterized in that

Reacting an inorganic tricyanoborate of formula I (wherein R is¹Is C_1-6Alkyl radical, C_2-6Alkenyl radical, C_6-10Aryl or benzyl, X is oxygen or sulfur, and Catⁿ⁺Is preferably selected from the group consisting of Li⁺、Na⁺、K⁺、Rb⁺、Cs⁺、NH₄ ⁺、Be²⁺、Mg²⁺、Ca²⁺、Sr²⁺And Ba²⁺Inorganic cation M of the groupⁿ⁺(wherein n is 1 or 2)),

and formula (Q)ⁿ⁺)_p(Y^p-) Salt reaction of n, wherein

Qⁿ⁺Is an organic cation, especially an organic cation containing at least one heteroatom selected from the group consisting of nitrogen, phosphorus, sulfur and oxygen,

n is 1 or 2, and n is a hydrogen atom,

Y^p-is an anion selected from the group consisting of halide, pseudohalide, sulfate and organic acid anion, and

p is 1 or 2.

In a preferred embodiment, the inorganic tricyanoborate used is prepared beforehand according to the method for its preparation as claimed above.

As formula (Q)ⁿ⁺)(Y^-)_nThe halide ion of the anion Y-of the salt may be selected from the group consisting of fluoride, chloride, bromide and iodide. Particularly preferred is chloride ion.

For salt (Q)ⁿ⁺)(Y^-)_nThe pseudohalide anion Y-in (1) may use an anion consisting of at least two electronegative atoms and being chemically similar to halogen. The pseudohalide anion is preferably selected from the group consisting of CN^-、OCN^-、SCN^-And N₃ ^-And (c) groups of (a). The pseudohalide anion is more preferably CN^-。

Suitable examples of organic acid anions are anions of mono-and dibasic non-aromatic and aromatic acids, such as acetate, oleate, fumarate, maleate, pyruvate, oxalate and benzoate. More preferred are acetate and pyruvate anions.

When n and p are 1, and when n and p are 2, the inorganic tricyanoborate and the salt of formula QY as defined above are preferably used in a molar ratio of 0.8:1.0 to 1.2:1.0, in particular in a molar ratio of 0.9:1.0 to 1.1: 1.0.

The reaction is preferably carried out in a solvent or solvent mixture, for example in a biphasic solvent mixture comprising water and at least one organic solvent, for example in a mixture of water and dichloromethane. Alternatively, the reaction can also be carried out without solvent or in an organic solvent in which the inorganic salts formed as by-products are poorly soluble or insoluble. Alternatively, the reaction may be carried out in an aqueous solution using a previously loaded ion exchanger.

The process for preparing the organotricyanoborate is preferably carried out at a temperature of from 10 ℃ to 250 ℃, in particular at a temperature in the range from room temperature to 100 ℃.

Detailed Description

Abbreviations:

TMSCN = cyanotrimethylsilane

TMSOMe = methoxytrimethylsilane

EA = elemental analysis

CP-OES = inductively coupled plasma optical emission spectrometry

br = broad peak

Example 1: synthesis of potassium tricyanomethoxyborate K [ B (CN) ₃ (OCH ₃ )]

Mixing B (OCH)₃)₃(20.0 g, 0.19 mol) and KCN (12.5 g, 0.19 mol) were dissolved in TMSCN (66.8 g, 0.67 mol) and heated under protective gas at reflux temperature of 70 ℃ for 18 hours. After cooling, all volatile constituents (unreacted TMSCN, formed TMSOMe) were distilled offTo obtain powder K [ B (CN)₃(OCH₃)]Yield 27.8g (92%).

¹H-NMR(400MHz,CD₃CN,TMS):δ[ppm]=3.22(q,J_H/B=3.5Hz,3H)。

¹³C-NMR(125MHz,CD₃CN,TMS):δ[ppm]=53.26(s), 128.7(q (80%) + heptad (20%), q: J =69.9Hz, heptad: J =23.0 Hz).

¹¹B-NMR(160.3MHz,CD₃CN,BF₃·Et₂O (external standard)) < delta [ ppm ]]=-18.5(s)。

IR (liquid Paraffin (Nujol)): v [ cm [^-1]=2228,2163,1201,1221br,965,926,866。

Melting point: 240 ℃ (decomposition).

And (3) analysis:

element(s)	C	H	N	B	K
						Method of producing a composite material	EA	EA	EA	CP-OES	CP-OES
Theoretical value%	30.22	1.90	26.43	6.80	24.29
						Measured value,%)	30.50	2.20	25.70	6.90	21.13

Example 2: synthesis of 1-ethyl-3-methylimidazolium tricyanomethoxyborate (Ionium) Liquid)

1-Ethyl-3-methylimidazolium chloride (5.0 g, 34 mmol), K [ B (CN)₃(OCH₃)]An aqueous solution of (5.4 g, 34 mmol) and water (25.1 g) was mixed with dichloromethane (67 g) and stirred at room temperature for 1 hour. After separation of the aqueous and organic phases, the organic phase was washed with 10ml of water and evaporated on a rotary evaporator to give 5.81g (74%) of 1-ethyl-3-methylimidazolium tricyanomethoxyborate as a colorless, low-viscosity liquid which did not solidify even at a temperature of-10 ℃.

¹H-NMR(400MHz,CD₃CN,TMS):δ[ppm]=1.62(br t,J=7.0Hz,3H),3.33(q,J_H/B=3.5Hz,3H),4.01(s,3H),4.30(br q,J=7,0Hz,2H),7.36(s,1H),7.39(s,1H),8.67(s,1H)。

¹³C-NMR(125MHz,CD₃CN,TMS):δ[ppm]=15.1(s),36.8(br),45.7(s),53.3(s),122.3(br),124.0(br),128.3(q (80%) + heptad (20%), q: J =69.9Hz, heptad: J =23.0 Hz).

Melting point: below 0 ℃.

Example 3: synthesis of 1-ethyl-3-methylimidazolium tricyanomethoxyborate (Ionium) Liquid)

A solution of 1-ethyl-3-methylimidazolium chloride (5.0 g, 34 mmol) in water (25 ml) was mixed with K [ B (CN)₃(OCH₃)](5.4 g, 34 mmol) was mixed with dichloromethane (67 g) and stirred at room temperature for 3 hours. After separation of the aqueous and organic phases, the latter are washed with 10ml of water, dried over potassium carbonate and finally evaporated on a rotary evaporator, giving 3.78g (48%) of 1-ethyl-3-methylimidazolium tricyanomethoxyborate as a low-viscosity liquid.

¹H-NMR(400MHz,CD₃CN,TMS):δ[ppm]=1.62(br t,J=7.0Hz,3H),3.33(q,J_H/B=3.5Hz,3H),4.01(s,3H),4.30(br q,J=7,0Hz,2H),7.36(s,1H),7.39(s,1H),8.67(s,1H)。

¹³C-NMR(125MHz,CD₃CN,TMS):δ[ppm]=15.1(q),36.8(br),45.7(br),53.3(q),122.3(br),124.0(br),128.3(q (80%) + heptad (20%), q: J =69.9Hz, heptad: J =23.2Hz),135.7 (d).

Melting point: below 0 ℃.

Example 4: synthesis of N-N-butyl-2-methylpyridinium tricyanomethoxyborate Liquid)

A solution of N-N-butyl-2-methylpyridinium chloride (5.0 g, 27 mmol) in water (20 ml) was combined with K [ B (CN)₃(OCH₃)](4.3 g, 27 mmol) was mixed with dichloromethane (53 g) and stirred at room temperature for 5 hours. After separation of the aqueous and organic phases, the latter are washed with 10ml of water, dried over potassium carbonate and finally evaporated on a rotary evaporator, giving 4.0g (55%) of N-N-butyl-2-methylpyridinium tricyanomethoxyborate as a low-viscosity liquid.

¹H-NMR(500MHz,CD₃CN,TMS):δ[ppm]=0.92(t,J=7.3Hz,3H),1.35-1.43(m,2H),1.79-1.83(m,2H),2.74(s,3H),3.15(q,J_H/B=3.9Hz,3H),4.39(br t,J=8Hz,2H),7.76-7.82(m,2H),8.26-8.30(m,1H),8.52-8.54(m,1H)。

¹³C-NMR(125MHz,CD₃CN,TMS):δ[ppm]=12.9(q),19.4(q),19.7(t),31.7(t),52.5(q),58.0(t),126.0(d),128.0(q (80%) + heptad (20%), q: J =69.9Hz, heptad: J =20.7Hz),130.5(d),145.1(d),145.3(d), 155.61(s).

Melting point: below 0 ℃.

Example 5: synthesis of Tetraethylammonium tricyanomethoxyborate (Ionic liquid)

A solution of tetraethylammonium chloride (5.0 g, 30 mmol) in water (22 ml) was combined with K [ B (CN)₃(OCH₃)](4.8 g, 30 mmol) was mixed with dichloromethane (59 g) and stirred at room temperature for 5 hours. After separation of the aqueous and organic phases, the latter are washed with 10ml of water, dried over potassium carbonate and finally evaporated on a rotary evaporator, giving 4.0g (53%) of tetraethylammonium tricyanomethoxyborate as a low-viscosity liquid.

¹H-NMR(500MHz,CD₃CN,TMS):δ[ppm]=1.16(tt,J=7.3,J_H/N=1.9Hz,12H),3.12(q,J=7.3Hz,8H),3.16(J_H/B=3.4Hz,3H)。

¹³C-NMR(125MHz,CD₃CN,TMS):δ[ppm]=6.8(q),52.3(dt,J_C/N=3.2Hz),54.5(q),128.0(q (80%) + heptad (20%), q: J =70Hz, heptad: J =23.5 Hz).

Melting range (DSC) between 1 ℃ and 26 ℃.

Example 6: synthesis of tetrabutylphosphonium tricyanomethoxyborate (Ionic liquid)

A solution of tetrabutylphosphonium methanesulfonate (5.0 g, 14 mmol) in water (10.4 ml) was combined with K [ B (CN)₃(OCH₃)](2.2 g, 14 mmol) was mixed with dichloromethane (27.6 g) and stirred at room temperature for 5 hours. After separation of the aqueous and organic phases, the latter are washed with 10ml of water, dried over potassium carbonate and finally evaporated on a rotary evaporator, 3.4g (64%) of tetrabutylphosphonium tricyanomethoxyborate are obtained in the form of a low-viscosity liquid.

¹H-NMR(500MHz,CD₃CN,TMS):δ[ppm]=0.95(t,J=7.3Hz,12H),1.44-1.53(m,16H),2.04-2.10(m,8H),3.21(J_H/B=3.4Hz,3H)。

¹³C-NMR(125MHz,CD₃CN,TMS):δ[ppm]=13.76(br q),19.2(td,J_P/C=48.3Hz),24.1(td,J_P/C=4.6Hz),24.7(td,J_P/C=15.6),53.4(q),128.0(q+m,q:J=70Hz)。

Melting point: below 0 ℃.

Claims (16)

1. A tricyanoborate of the formula,

wherein

R¹Is C_1-6Alkyl radical, C_2-6Alkenyl radical, C_6-10An aryl group or a benzyl group,

x is oxygen or sulfur, and

Catⁿ⁺is selected fromOrganic cations and cations of the group consisting of organic cations, wherein n is 1 or 2.

2. The tricyanoborate according to claim 1, wherein X is oxygen.

3. The tricyanoborate according to claim 1 or 2, wherein R¹Is methyl, ethyl or propyl.

4. The tricyanoborate according to claim 3, wherein R¹Is methyl.

5. The tricyanoborate according to claim 1, wherein Catⁿ⁺Is an inorganic cation selected from the group consisting of: li⁺、Na⁺、K⁺、Rb⁺、Cs⁺、NH₄ ⁺、Be²⁺、Mg²⁺、Ca²⁺、Sr²⁺And Ba²⁺。

6. The tricyanoborate according to claim 1, wherein Catⁿ⁺Is an organic cation containing at least one heteroatom selected from the group consisting of nitrogen, phosphorus, sulfur and oxygen.

7. The tricyanoborate according to claim 6, wherein the organic cation is selected from the group consisting of cations of the formula:

（a）(WR²R³R⁴R⁵)⁺wherein W is nitrogen or phosphorus, and

(i) wherein R is²To R⁴Independently is C_1-20Alkyl, and R⁵Is C_1-20Alkyl radical, C_3-10Cycloalkyl or C_6-10Aryl, wherein R²To R⁵Independently optionally containing one or more halogens, or

(ii) Wherein R is²And R³Together with W form a 5-to 7-membered ring, and R⁴And R⁵Independently is C_1-20Alkyl radical, wherein R⁴And R⁵Independently optionally containing one or more halogens, or

(iii) Wherein R is²And R³Or R⁴And R⁵In each case together with W form a 5-to 7-membered ring, or

（b）(XR⁶R⁷R⁸)⁺Wherein X is nitrogen, and R⁶And R⁷Form a ring together with X, wherein X is formally bonded to R via one single bond and one double bond⁶And R⁷And R is⁸Is C_1-20Alkyl radical, C_3-10Cycloalkyl or C_6-10Aryl, wherein R⁸Optionally containing one or more halogens, or

（c）(YR⁹R¹⁰R¹¹)⁺Wherein Y is sulfur, and

(i) wherein R is⁹And R¹⁰Independently is C_1-20Alkyl, and R¹¹Is C_1-20Alkyl radical, C_3-10Cycloalkyl or C_6-10Aryl, wherein R⁹To R¹¹Independently optionally containing one or more halogens, or

(ii) Wherein R is⁹And R¹⁰Together with Y form a 5-to 7-membered ring, and R¹¹Is C_1-20Alkyl radical, C_3-10Cycloalkyl or C_6-10Aryl, wherein R¹¹Optionally containing one or more halogens, or

（d）(ZR¹²R¹³)⁺Wherein Z is oxygen or sulfur, and R¹²And R¹³Form a ring together with Z, wherein Z is formally bonded to R via one single bond and one double bond¹²And R¹³And is and

wherein one or more than one is selected from the group consisting of C_1-20Alkyl radical, C_1-20Alkoxy radical, C_3-10Cycloalkyl radical, C_6-10The substituents of the group consisting of aryl, halogen and cyano being optionally bound to the substituent R²To R¹³Each ring formed wherein said C_1-20Alkyl radical, said C_1-20Alkoxy radical, said C_3-10Cycloalkyl and said C_6-10Aryl independently optionally contains one or more halogens, and

wherein by a substituent R²To R¹³Each ring formed optionally contains one or two further substituted or unsubstituted heteroatoms selected from the group consisting of nitrogen, sulfur and oxygen, and/or is fused to another aromatic or non-aromatic 5-to 7-membered ring.

8. The tricyanoborate according to claim 6 or 7, wherein the organic cation is selected from the group consisting of: organic ammonium, phosphonium, sulfonium, pyrrolidinium, pyrrolinium, pyrrolidinium, pyrazolium, imidazolium, triazolium, oxazolium, thiazolium, piperidinium, piperazinium, morpholinium, pyridinium, pyridazinium, pyrimidinium, pyrazinium, 1, 3-dioxolinium, pyrylium, and thiopyrylium cations.

9. The tricyanoborate according to claim 6, wherein the organic cation is selected from the group consisting of:

wherein R and R' are independently C_1-20Alkyl, and m is an integer of 0 to 4.

10. The tricyanoborate according to claim 9, wherein R and R' are independently C_1-14An alkyl group.

11. The tricyanoborate according to claim 9, wherein the organic cation has the formula,

wherein R and R' are independently C_1-20An alkyl group.

12. The tricyanoborate according to claim 11, wherein R and R' are independently C_1-14An alkyl group.

13. The tricyanoborate according to claim 11, wherein R is methyl and R' is ethyl.

14. Use of a tricyanoborate as defined in any one of claims 6 to 13, optionally in admixture with one or more other ionic liquids, water or organic solvents, as a polar aprotic solvent.

15. Process for the preparation of the tricyanoborate as defined in claim 5, characterized in that B (XR) is reacted¹)₃With cyano-tri-C_1-6Alkylsilanes in Mⁿ⁺(CN^-)_nIn the presence of a catalyst, reacting the mixture,

wherein

R¹Is C_1-6Alkyl radical, C_2-6Alkenyl radical, C_6-10An aryl group or a benzyl group,

x is oxygen or sulfur, and

Mⁿ⁺is selected from Li⁺、Na⁺、K⁺、Rb⁺、Cs⁺、NH₄ ⁺、Be²⁺、Mg²⁺、Ca²⁺、Sr²⁺And Ba²⁺Inorganic cations of the group, wherein n is 1 or 2.

16. A process for preparing the tricyanoborate as defined in any one of claims 6 to 13, characterized in that a tricyanoborate as defined in claim 5 is reacted with a compound of formula (Q)ⁿ⁺)_p(Y^p-)_nThe salt is reacted with the acid to react,

wherein

Qⁿ⁺Is an organic cation as defined in any one of claims 6 to 13,

n is 1 or 2, and n is a hydrogen atom,

Y^p-is an anion selected from the group consisting of halide, pseudohalide, sulfate and organic acid anion, and

p is 1 or 2, and p is,

wherein the tricyanoborate used has been previously prepared according to the method as defined in claim 15.