JP2008285414A - Phosphonium-type ionic liquid containing amino acid as constituent ion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-viscosity ionic liquid easily available at a low cost and useful as a chiral derivative being friendly to the environment and as a new solvent. <P>SOLUTION: The organic ionic liquid is a quaternary phosphorus compound expressed by general formula I: [wherein Ph<SP>+</SP>as the cation moiety is (R<SP>1</SP>R<SP>2</SP>R<SP>3</SP>R<SP>4</SP>)P<SP>+</SP>(wherein R<SP>1</SP>, R<SP>2</SP>, R<SP>3</SP>and R<SP>4</SP>are each independently a substituted or unsubstituted lower alkyl) or a cation derived from a substituted or unsubstituted heterocycle containing one or more phosphorus atoms as ring constituent(s) by bonding one proton or one alkyl group to the phosphorus atom; and the anion moiety is an amino acid anion (wherein Y is a residue derived from an amino acid by removing the amino and carboxy groups)]. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an organic ionic liquid which is a quaternary phosphorus compound represented by the general formula I.

The ionic liquid is a generic name for salts having a melting point of about 100 ° C. or less, which is also called an ionic liquid, and is attracting attention as a third solvent after water and organic solvents (for example, Non-Patent Document 1). The ionic liquid is synthesized by combining a cation and an anion which are advantageous for forming the ionic liquid. The cations that have been used so far include imidazolium cations, pyridinium cations, alkylammonium cations, etc., and the anions include BF ₄ ⁻ , PF ₆ ⁻ , CF ₃ SO ₃ ⁻ , and imide anions ((CF ₃ SO ₃ ). ₂ N ⁻ ), CH ₃ COO ⁻ , CF ₃ COO ⁻ , NO ₃ ⁻ , (CN) ₂ N ⁻ and the like.

  The characteristics of these ionic liquids are that they have a very wide temperature range for maintaining a liquid state, they are liquid and have almost no vapor pressure, are non-volatile and non-flammable, and are liquids that consist only of ions, so they have high ionic conductivity. A high degree of solubility in various organic compounds, and a liquid phase that depends on the combination of ions but is immiscible with water or a general-purpose organic solvent. Based on these characteristics, ionic liquids are not only applied as various synthetic solvents, separation / extraction solvents, and enzyme reaction solvents, but also energetically studied as electrolyte materials for batteries and fuel cells (for example, Patent Document 1). Has been.

  Among these applications, reports as various synthetic solvents are outstanding. The characteristics of ionic liquids are useful for minimizing diffusion into the living environment and are excellent for repeated use. Therefore, they are considered to be suitable as environmentally friendly solvents and substitutes for conventional solvents. Yes. So far, reports have been made on Friedel-Crafts reaction, Diels-Alder reaction, Heck reaction, Suzuki coupling reaction, Beckmann transfer reaction and the like (for example, Patent Document 2). These are just a few examples, and a very large number of reactions are under consideration. In any case, it has been clarified that the ionic liquid can be repeatedly used as a reaction solvent, and that the yield and reaction selectivity superior to those of conventional solvents can be obtained depending on the reaction.

  One of the most important reactions among these organic syntheses is an asymmetric synthesis reaction. Asymmetric synthesis occupies an extremely important position not only in the field of organic chemistry but also in the fields of biochemistry and pharmacology. Until now, optically active reagents and chiral catalysts have been used as asymmetric derivatives, but the synthesis of chiral ionic liquids having asymmetry in the cation or anion moiety has already been studied. When a chiral ionic liquid is used in the Diels-Alder reaction, remarkable results such as shortening of the reaction time, improvement of yield, and improvement of selectivity of the reaction position can be obtained even though no asymmetric derivative is added. Yes. However, there are many points to be improved in the chiral ionic liquids reported so far.

  Disadvantages of conventional chiral ionic liquids are as follows: (1) A system having a chiral site in a cation structure such as an imidazolium cation or an ammonium cation has a complicated synthesis procedure and it is not easy to obtain a high-purity product; ) Synthesis of ionic liquids using chiral salts is an anion exchange reaction as in the conventional system, so the starting material is expensive; (3) Optical purity is not 100%; (5) Melting point is higher than room temperature There are many high systems; (6) high viscosity (has drawbacks such as racemization and thermal denaturation because heat treatment is required).

There have been reports of attempts to synthesize chiral ionic liquids using natural amino acids as starting materials (for example, Non-Patent Document 2). Since the functional group is substituted from a carboxyl group to an alcohol during synthesis, and a bulky amino acid derivative is introduced into the side chain of the imidazolium cation, the melting point of the obtained salt is relatively high, and it cannot be said to be an ionic liquid. It was. Moreover, the ionic liquid (patent document 3) synthesized by combining a natural amino acid with an onium cation may have a very high viscosity depending on the side chain structure of the amino acid.
JP 2000-3620 A JP 2002-275118 A JP 2004-269414 A Hiroyuki Ohno, "Organic ionic liquids-polar liquids that do not evaporate", Future Materials, 2002, Vol. 2, No. 9, pp. 6-11 Weiliang Bao, Zhimiang Wang and Yuxia Li, Journal of Organic Chemistry, 2003, 68 (2), 591-593

  It is an object of the present invention to provide a new ionic liquid.

［式中、カチオン部Ｐｈ^＋は、（Ｒ^１Ｒ^２Ｒ^３Ｒ^４）Ｐ^＋（ここで、Ｒ^１、Ｒ^２、Ｒ^３、およびＲ^４は、それぞれ独立して、非置換もしくは置換された低級アルキル基）であるか、または１もしくはそれ以上の燐原子を環員として含む、非置換もしくは置換されたヘテロ環の燐原子にプロトンもしくはアルキル基が１つ結合したカチオンであり、アニオン部は、アミノ酸アニオン（ここで、Ｙは、アミノ酸のアミノ基およびカルボキシル基を除いた構成部分）である］
で示される第４級燐化合物である有機イオン液体を提供する。 The present invention is directed to general formula I:

[Wherein the cation moiety Ph ⁺ is (R ¹ R ² R ³ R ⁴ ) P ⁺ (wherein R ¹ , R ² , R ³ , and R ⁴ are each independently unsubstituted or substituted) A lower alkyl group), or a cation in which one proton or an alkyl group is bonded to the phosphorus atom of an unsubstituted or substituted heterocyclic ring containing one or more phosphorus atoms as ring members. Is an amino acid anion (where Y is a component excluding the amino group and carboxyl group of the amino acid)]
The organic ionic liquid which is the quaternary phosphorus compound shown by these is provided.

  Here, the lower alkyl group means a saturated linear or branched hydrocarbon residue having 1 to 12 carbon atoms, preferably a hydrocarbon residue having 2 to 6 carbon atoms, more preferably 2 to 4 carbon atoms. Say. For example, methyl, ethyl, propyl, isopropyl, butyl, s-butyl, t-butyl, pentyl, hexyl and the like can be mentioned, preferably ethyl, propyl, isopropyl, butyl, pentyl, hexyl, more preferably Propyl and butyl.

Examples of the substituent for the lower alkyl group include hydroxy, lower alkoxy having 1 to 4 carbon atoms, a lower alkyl group having 1 to 4 carbon atoms substituted by the alkoxy group, an amino group, and the like.
As the substituent of the heterocyclic ring of the formula I, the lower alkyl group having 1 to 12 carbon atoms, preferably 1 to 6 carbon atoms, more preferably 3 to 6 carbon atoms, hydroxy, 1 to 4 carbon atoms. A lower alkoxy, a C1-C4 lower alkyl group substituted by the alkoxy group, an amino group, and the like are applicable. Of the lower alkyl groups, propyl and butyl are particularly preferred.
The amino acid in the anion moiety is not particularly limited as long as it is an optically active aminocarboxylic acid as well as α-amino acid, but α-amino acid is preferable, and natural α-amino acid is particularly preferable.

  The present invention provides an organic ionic liquid which is a quaternary phosphorus compound having an amino acid, particularly a natural amino acid, which is inexpensive and easily available, as a constituent ion. According to the present invention, a low-viscosity and optically active environment that has heretofore been difficult to synthesize can be easily obtained at low cost. That is, according to the present invention, a salt with an appropriate phosphonium cation using a natural amino acid or the like is used so that the optical purity is 100%, the liquid state is maintained in a wide temperature range from below freezing to over 300 ° C., and the viscosity becomes low. An ionic liquid is provided. This ionic liquid can be used in all application fields of ordinary ionic liquids, and also has the possibility of being used for the creation of various functional molecules as amino acid reaction precursors.

Examples of lower alkyl cation (R ¹ R ² R ³ R ⁴ ) P ⁺ include lower alkylphosphonium, and examples of heterocyclic cation include phosphorium, phospholium, dibenzophospholium, phosphine, Phosphorinanium, dibenzophosphonininanium, phosphorinoindolium, phosphoniabicyclooctane, phosphorinophosphinolidinium, phosphorinopyrimidinium, phosphorinium, phosphinolinium, phosphinodridinium Preferable are phospholium and phosphorinalium.

  The anion is preferably an anion of D- or L-amino acid, more preferably a natural α-amino acid, still more preferably L-asparagine, L-aspartic acid, L-alanine, L-arginine, L-isoleucine, Glycine, L-glutamine, L-glutamic acid, L-cysteine, L-serine, L-tyrosine, L-tryptophan, L-threonine, L-valine, L-histidine, L-phenylalanine, L-proline, L-methionine, An anion of an amino acid selected from L-lysine or L-leucine.

General Method for Producing Quaternary Phosphorus Compounds of the Present Invention In an aqueous solvent of a Ph ⁺ hydroxy compound in the cation portion, about 1-1 amino acids that become the anion portion H ₂ N—Y—C (═O) —O ^— .4 parts by weight, preferably about 1.0 part by weight, is added, the resulting mixed solution is stirred under ice-cooling, the solvent is distilled off under reduced pressure, and unreacted amino acids are removed from the residue by an appropriate method. To obtain a quaternary phosphorus compound as a desired ionic liquid.

Hereinafter, the present invention will be described specifically by way of examples. In any of the Examples, the target product was obtained as a liquid material at room temperature, but the present invention is not limited to these. The progress of the neutralization reaction between the tetraalkylphosphonium hydroxide and the amino acid in these examples was confirmed by ¹ H-NMR measurement.

Example 1
5 g of L-alanine was added to 26.6 g of 41.6 wt% tetrabutylphosphonium hydroxide aqueous solution, and the mixture was dried under reduced pressure while stirring to remove excess water. To this, 60 ml of acetonitrile and 40 ml of methanol were added and stirred. Thereafter, the crystals (unreacted alanine added in excess) were removed by filtration, and the filtrate was dried by heating under reduced pressure to remove acetonitrile and methanol to obtain 11 g of tetrabutylphosphonium alanine (yield 80%). The result of ¹ H-NMR measurement of this product is as shown in FIG. 1, and the progress of the reaction was confirmed from the chemical shift of proton and the integrated intensity.
¹ H-NMR (DMSO, δ / ppm TMS standard): 0.917 (t, 12H, J = 14.5 Hz), 0.982 (t, 3H, J = 7 Hz), 1.369-1.503 ( m, 16H), 2.214 (m, 8H, J = 30 Hz), 2.769 (q, 1H, J = 20 Hz)

Example 2
4 g of L-glycine was added to 26.6 g of 41.6 wt% tetrabutylphosphonium hydroxide aqueous solution, and the mixture was stirred and dried under reduced pressure to remove excess water. To this, 60 ml of acetonitrile and 40 ml of methanol were added and stirred. Thereafter, crystals (unreacted glycine added in excess) were removed by filtration, and the filtrate was dried by heating under reduced pressure to remove acetonitrile and methanol to obtain 11 g of tetrabutylphosphonium glycine (yield 83%). As a result of ¹ H-NMR measurement of this product, the progress of the reaction was confirmed from the chemical shift of proton and the integrated intensity.
¹ H-NMR (DMSO, δ / ppm TMS standard): 0.918 (t, 12H, J = 14 Hz), 1.368-1.500 (m, 16H), 2.200 (m, 8H, J = 30 Hz), 2.630 (q, 1 H, J = 6.5 Hz)

Example 3
7 g of L-aspartic acid was added to 26.6 g of a 41.6 wt% tetrabutylphosphonium hydroxide aqueous solution, and the mixture was stirred and dried under reduced pressure to remove excess water. To this, 60 ml of acetonitrile and 40 ml of methanol were added and stirred. Thereafter, the crystals precipitated by filtration (unreacted aspartic acid added in excess) were removed, and the filtrate was heated and dried under reduced pressure to remove acetonitrile and methanol to obtain 10 g of tetrabutylphosphonium aspartic acid (yield 65%). It was. As a result of ¹ H-NMR measurement of this product, the progress of the reaction was confirmed from the chemical shift of proton and the integrated intensity.
¹ H-NMR (DMSO, δ / ppm TMS standard): 0.917 (t, 12H, J = 14.5 Hz), 1.369-1.502 (m, 16H), 2.191 (m, 8H) , J = 29.5 Hz), 2.188 (m, 2H, J = 139 Hz), 3.170 (t, 1H, J = 14 Hz)

Example 4
7.6 g of L-glutamic acid was added to 26.6 g of 41.6 wt% tetrabutylphosphonium hydroxide aqueous solution, and the mixture was dried under reduced pressure with stirring to remove excess water. To this, 60 ml of acetonitrile and 40 ml of methanol were added and stirred. Thereafter, the crystals precipitated by filtration (unreacted glutamic acid added in excess) were removed, and the filtrate was dried by heating under reduced pressure to remove acetonitrile and methanol to obtain 10 g (yield 65%) of tetrabutylphosphonium glutamic acid. As a result of ¹ H-NMR measurement of this product, the progress of the reaction was confirmed from the chemical shift of proton and the integrated intensity.
¹ H-NMR (DMSO, δ / ppm TMS standard): 0.918 (t, 12H, J = 14 Hz), 1.368-1.498 (m, 16H), 2.179 (m, 8H, J = 30 Hz), 1.620-2.131 (m, 4H)

Example 5
5 g of L-lysine was added to 26.6 g of 41.6 wt% tetrabutylphosphonium hydroxide aqueous solution, and the mixture was dried under reduced pressure while stirring to remove excess water. To this, 60 ml of acetonitrile and 40 ml of methanol were added and stirred. Thereafter, the crystals (unreacted lysine added in excess) were removed by filtration, and the filtrate was heated and dried under reduced pressure to remove acetonitrile and methanol to obtain 13 g of tetrabutylphosphonium lysine (yield 78%). As a result of ¹ H-NMR measurement of this product, the progress of the reaction was confirmed from the chemical shift of proton and the integrated intensity.
¹ H-NMR (DMSO, δ / ppm TMS standard): 0.917 (t, 12H, J = 14.5 Hz), 1.245-1.878 (m, 22H), 2.216 (m, 8H) , J = 30 Hz), 2.679 (q, 1H, J = 12 Hz)

Example 6
7.6 g of L-asparagine was added to 26.6 g of 41.6 wt% tetrabutylphosphonium hydroxide aqueous solution, and the mixture was stirred and dried under reduced pressure to remove excess water. To this, 60 ml of acetonitrile and 40 ml of methanol were added and stirred. Thereafter, the crystals (unreacted asparagine added in excess) were removed by filtration, and the filtrate was heated and dried under reduced pressure to remove acetonitrile and methanol to obtain 10 g of tetrabutylphosphonium asparagine (yield 70%). As a result of ¹ H-NMR measurement of this product, the progress of the reaction was confirmed from the chemical shift of proton and the integrated intensity.
¹ H-NMR (DMSO, δ / ppm TMS standard): 0.917 (t, 12H, J = 14.5 Hz), 1.369-1.501 (m, 16H), 2.198 (m, 8H) , J = 23 Hz), 1.910-2.389 (m, 2H), 3.037 (s, 1H), 6.557 (s, 1H), 8.213 (s, 1H)

Example 7
7.5 g of L-glutamine was added to 26.6 g of a 41.6 wt% tetrabutylphosphonium hydroxide aqueous solution, and the mixture was stirred under reduced pressure to remove excess water. To this, 60 ml of acetonitrile and 40 ml of methanol were added and stirred. Thereafter, the crystals precipitated by filtration (unreacted glutamine added in excess) were removed, and the filtrate was heated and dried under reduced pressure to remove acetonitrile and methanol to obtain 11 g of tetrabutylphosphonium glutamine (yield 72%). As a result of ¹ H-NMR measurement of this product, the progress of the reaction was confirmed from the chemical shift of proton and the integrated intensity.
¹ H-NMR (DMSO, δ / ppm TMS standard): 0.915 (t, 12H, J = 20 Hz), 1.369-1.685 (m, 18H), 2.042 (m, 2H, J = 80 Hz), 2.236 (m, 8H, J = 30 Hz), 2.764 (q, 1H, J = 12.5 Hz)

Example 8
7 g of L-histidine was added to 26.6 g of 41.6 wt% tetrabutylphosphonium hydroxide aqueous solution, and the mixture was stirred and dried under reduced pressure to remove excess water. To this, 60 ml of acetonitrile and 40 ml of methanol were added and stirred. Thereafter, the crystals precipitated by filtration (unreacted histidine added in excess) were removed, and the filtrate was heated and dried under reduced pressure to remove acetonitrile and methanol to obtain 13 g of tetrabutylphosphonium histidine (yield 80%). As a result of ¹ H-NMR measurement of this product, the progress of the reaction was confirmed from the chemical shift of proton and the integrated intensity.
¹ H-NMR (CDCl ₃ , δ / ppm TMS standard): 0.968 (t, 12H, J = 14 Hz), 1.500 (m, 16H, J = 15 Hz), 2.331 (m, 8H) , J = 29.5 Hz), 2.958 (m, 2H, J = 335 Hz), 3.417 (q, 1H, J = 17 Hz), 6.754 (s, 1H), 7.430 ( s, 1H)

Example 9
8 g of L-isoleucine was added to 26.6 g of a 41.6 wt% tetrabutylphosphonium hydroxide aqueous solution, and the mixture was dried under reduced pressure while stirring to remove excess water. To this, 60 ml of acetonitrile and 40 ml of methanol were added and stirred. Thereafter, the crystals precipitated by filtration (unreacted isoleucine added in excess) were removed, and the filtrate was heated and dried under reduced pressure to remove acetonitrile and methanol to obtain 13 g of tetrabutylphosphonium isoleucine (yield 83%). As a result of ¹ H-NMR measurement of this product, the progress of the reaction was confirmed from the chemical shift of proton and the integrated intensity.
¹ H-NMR (DMSO, δ / ppm TMS standard): 0.750-0.783 (m, 6H), 0.917 (t, 12H, J = 14 Hz), 0.9845 (m, 1H, J = 30.5 Hz), 1.309-1.585 (m, 18H), 2.228 (m, 8H, J = 30 Hz), 2.612 (d, 1H, J = 4.5 Hz)

Example 10
6.8 g of L-leucine was added to 26.6 g of a 41.6 wt% tetrabutylphosphonium hydroxide aqueous solution, and the mixture was stirred under reduced pressure to remove excess water. To this, 60 ml of acetonitrile and 40 ml of methanol were added and stirred. Thereafter, the crystals (unreacted alanine added in excess) were removed by filtration, and the filtrate was dried by heating under reduced pressure to remove acetonitrile and methanol to obtain 11 g of tetrabutylphosphonium leucine (yield 70%). As a result of ¹ H-NMR measurement of this product, the progress of the reaction was confirmed from the chemical shift of proton and the integrated intensity.
¹ H-NMR (DMSO, δ / ppm TMS standard): 0.819 (q, 6H, J = 25 Hz), 0.918 (t, 12H, J = 14.5 Hz), 1.006 (m, 1H, J = 42.5 Hz), 1.359-1.500 (m, 16H), 1.680 (m, 1H, J = 33.5 Hz), 2.205 (m, 8H, J = 29) .5 Hz), 2.699 (s, 1H)

Example 11
8.5 g of L-phenylalanine was added to 26.6 g of 41.6 wt% tetrabutylphosphonium hydroxide aqueous solution, and the mixture was dried under reduced pressure with stirring to remove excess water. To this, 60 ml of acetonitrile and 40 ml of methanol were added and stirred. Thereafter, crystals (unreacted phenylalanine added excessively) precipitated by filtration were removed, and the filtrate was heated and dried under reduced pressure to remove acetonitrile and methanol to obtain 13 g of tetrabutylphosphonium phenylalanine (yield 75%). As a result of ¹ H-NMR measurement of this product, the progress of the reaction was confirmed from the chemical shift of proton and the integrated intensity.
¹ H-NMR (DMSO, δ / ppm TMS standard): 0.916 (t, 12H, J = 14.5 Hz), 1.367-1.487 (m, 16H), 2.208 (m, 8H) , J = 29.5 Hz), 2.365 (q, 1H, J = 22.5 Hz), 2.983 (m, 2H, J = 45.5 Hz), 7.107-7.236 (m , 5H)

Example 12
5.5 g of L-serine was added to 26.6 g of a 41.6 wt% tetrabutylphosphonium hydroxide aqueous solution, and the mixture was stirred and dried under reduced pressure to remove excess water. To this, 60 ml of acetonitrile and 40 ml of methanol were added and stirred. Thereafter, the crystals (unreacted serine added in excess) were removed by filtration, and the filtrate was dried by heating under reduced pressure to remove acetonitrile and methanol to obtain 11 g of tetrabutylphosphonium serine (yield 73%). As a result of ¹ H-NMR measurement of this product, the progress of the reaction was confirmed from the chemical shift of proton and the integrated intensity.
¹ H-NMR (DMSO, δ / ppm TMS standard): 0.917 (t, 12H, J = 14 Hz), 1.369-1.500 (m, 16H), 2.191 (m, 8H, J = 29.5 Hz), 2.775 (q, 1H, J = 15.5 Hz), 3.133 (q, 1H J = 30.5 Hz), 3.255 (q, 1H, J = 15. 5 Hz)

Example 13
6.2 g of L-threonine was added to 26.6 g of a 41.6 wt% tetrabutylphosphonium hydroxide aqueous solution, and dried under reduced pressure while stirring to remove excess water. To this, 60 ml of acetonitrile and 40 ml of methanol were added and stirred. Thereafter, the crystals (unreacted threonine added in excess) were removed by filtration, and the filtrate was heated and dried under reduced pressure to remove acetonitrile and methanol to obtain 11 g of tetrabutylphosphonium threonine (yield 70%). As a result of ¹ H-NMR measurement of this product, the progress of the reaction was confirmed from the chemical shift of proton and the integrated intensity.
¹ H-NMR (DMSO, δ / ppm TMS standard): 0.880 (d, 3H, J = 6 Hz), 0.918 (t, 12H, J = 14 Hz), 1.383-1.488 ( m, 16H), 2.193 (m, 8H, J = 30.5 Hz), 2.842 (d, 1H, J = 4 Hz), 3.443 (m, 1H, J = 11 Hz)

Example 14
7.7 g of L-methionine was added to 26.6 g of 41.6 wt% tetrabutylphosphonium hydroxide aqueous solution, and the mixture was stirred and dried under reduced pressure to remove excess water. To this, 60 ml of acetonitrile and 40 ml of methanol were added and stirred. Then, the crystals precipitated by filtration (unreacted methionine added in excess) were removed, and the filtrate was heated and dried under reduced pressure to remove acetonitrile and methanol to obtain 12.2 g of tetrabutylphosphonium methionine (yield 75%). It was. As a result of ¹ H-NMR measurement of this product, the progress of the reaction was confirmed from the chemical shift of proton and the integrated intensity.
¹ H-NMR (CDCl ₃ , δ / ppm TMS standard): 0.918 (t, 12H, J = 14.5 Hz), 1.511-1.549 (m, 16H), 1.71-2. 148 (m, 5H), 2.413 (m, 8H, J = 29.5 Hz), 2.666 (m, 8H, J = 29.5 Hz), 3.218 (q, 1H, J = 12) .5 Hz)

Example 15
4.6 g of L-proline was added to 26.6 g of a 41.6 wt% tetrabutylphosphonium hydroxide aqueous solution, and the mixture was stirred under reduced pressure to remove excess water. To this, 60 ml of acetonitrile and 40 ml of methanol were added and stirred. Thereafter, crystals (unreacted proline added in excess) were removed by filtration, and the filtrate was dried by heating under reduced pressure to remove acetonitrile and methanol to obtain 11 g of tetrabutylphosphonium proline (yield 77%). As a result of ¹ H-NMR measurement of this product, the progress of the reaction was confirmed from the chemical shift of proton and the integrated intensity.
¹ H-NMR (CDCl ₃ , δ / ppm TMS standard): 0.976 (t, 12H, J = 14 Hz), 1.527 (m, 16H, J = 19 Hz), 1.657 (m, 2H) , J = 51 Hz), 1.870 (m, 1H, J = 32.5 Hz), 2.082 (m, 1H, J = 36 Hz), 2.395 (m, 8H, J = 29 Hz) , 2.784 (m, 1H, J = 17.5 Hz), 3.097 (m, 1H, J = 23 Hz), 3.511 (m, 1H, J = 14.5 Hz)

  The ionic liquid provided by the present invention can be used as an electrolyte material for batteries, fuel cells and the like as well as solvents for various synthetic reactions, separation / extraction solvents, and enzyme reaction solvents.

1 is a ¹ H-NMR chart of n-tetrabutylphosphonium alanine salt (Example 1).

Claims (6)

Formula I:

[Wherein the cation moiety Ph ⁺ is (R ¹ R ² R ³ R ⁴ ) P ^+, where R ¹ , R ² , R ³ and R ⁴ are each independently unsubstituted or substituted. A lower alkyl group), or a cation in which one proton or an alkyl group is bonded to the phosphorus atom of an unsubstituted or substituted heterocyclic ring containing one or more phosphorus atoms as ring members, , Amino acid anion (where Y is a component excluding the amino group and carboxyl group of the amino acid)]
A quaternary phosphorus compound represented by The quaternary phosphorus compound according to claim 1, wherein Ph ⁺ is (R ¹ ) ₄ P ⁺ (wherein R ¹ is an unsubstituted or substituted lower alkyl group). The quaternary phosphorus compound according to claim 2, wherein R ¹ is a butyl group.   The quaternary phosphorus compound according to any one of claims 1 to 3, wherein the amino acid anion is an α-amino acid anion.   The quaternary phosphorus compound according to any one of claims 1 to 4, wherein the amino acid anion is a natural α-amino acid anion. The amino acid anion is L-leucine, L-phenylalanine, L-isoleucine, glycine, L-glutamic acid, L-valine, L-aspartic acid, L-tryptophan, L-alanine, L-arginine, L-asparagine, L- The amino acid anion selected from the group consisting of cysteine, L-glutamine, L-histidine, L-lysine, L-methionine, L-serine, L-threonine, and L-tyrosine. 4. A quaternary phosphorus compound according to item 1.

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