JP6780945B2 - Ionic liquids, lubricants and magnetic recording media - Google Patents

Description

The present invention relates to an ionic liquid, a lubricant containing the ionic liquid, and a magnetic recording medium using the ionic liquid.

Conventionally, in a thin film magnetic recording medium, a lubricant is applied to the surface of the magnetic layer in order to reduce friction and wear between the magnetic head and the surface of the medium. The actual lubricant film thickness is at the molecular level to avoid sticking-like adhesions. Therefore, it is no exaggeration to say that the most important thing in a thin film magnetic recording medium is the selection of a lubricant having excellent wear resistance under any environment.

In the life of a magnetic recording medium, it is important that the lubricant is present on the surface of the medium without causing detachment, spin-off, chemical deterioration, or the like. The presence of the lubricant on the surface of the medium becomes more difficult as the surface of the thin film magnetic recording medium becomes smoother. This is because the thin film magnetic recording medium does not have the ability to replenish the lubricant like the coating type magnetic recording medium.

In addition, if the adhesive force between the lubricant and the protective film on the surface of the magnetic layer is weak, the lubricant film thickness will decrease during heating and sliding, which will accelerate wear, so a large amount of lubricant is required. It is said that. A large amount of lubricant becomes a mobile lubricant and can have a function of replenishing the lost lubricant. However, the dilemma is that excess lubricant makes the film thickness of the lubricant larger than the surface sparseness, which causes problems related to adhesion, and in a fatal case, it becomes stiction and causes drive failure. There is.

Further, as shown in FIG. 1, in Non-Patent Document 1, although the increase rate of the in-plane recording density of the hard disk drive of the product has decreased in recent years, the annual rate has reached 25%, which is one target of 4Tb. It is about to reach / in ² . As shown in FIG. 2, it can be seen that the distance between the head disk interfaces decreases with respect to the increase in the recording density, but there is always a need to improve the reliability accordingly. This is described in, for example, the following Non-Patent Documents 2 to 4.

The current recording density is about 1 Tb / in ² , the spacing is about 6 nm, the lubricant thickness is 0.8 nm, and the future 4 Tb / in ² recording density must also reduce the lubricant thickness. It doesn't become. However, in the conventional PFPE lubricant, it is necessary to reduce the molecular weight in order to reduce the film thickness, but there is a drawback that the thermal stability is deteriorated. It can be seen that these reliability problems have not been fully solved by conventional perfluoropolyether (PFPE) -based lubricants.

In particular, in a thin film magnetic recording medium having high surface smoothness, a new lubricant is molecularly designed and synthesized in order to eliminate these trade-offs. In addition, many reports on the lubricity of PFPE have been submitted. As described above, the lubricant is very important in the magnetic recording medium.

Table 1 shows the chemical structures of typical PFPE-based lubricants.

Z-DOL in Table 1 is one of the commonly used lubricants for thin film magnetic recording media. Further, it has been reported that Z-tellaol (ZTMD) further introduces a functional hydroxyl group into the main chain of PFPE and enhances the reliability of the drive while reducing the gap of the head media interface. It has been reported that A20H suppresses the decomposition of the PFPE main chain by Lewis acids and Lewis bases and improves tribological properties. On the other hand, it has been reported that the polymer main chain and polar group of Mono are polynormal propyloxy and amine, respectively, unlike the above-mentioned PFPE, and reduce the adhesive interaction in near contact.

However, common solid lubricants, which have a high melting point and are considered to be thermally stable, interfere with the highly sensitive electromagnetic conversion process and also wear due to the wear debris scraped by the head on the traveling truck. The characteristics deteriorate. As described above, the liquid lubricant has mobility such that the lubricant removed by the wear by the head is moved from the adjacent lubricating layer and replenished. However, due to this mobility, especially at high temperatures, the lubricant spins off from the disk surface during disk operation, resulting in loss of protective function. For this reason, a lubricant having high viscosity and low volatility is preferably used, which makes it possible to suppress the evaporation rate and extend the life of the disk drive.

In view of these lubrication mechanisms, the requirements for a low-friction, low-wear lubricant used in a thin-film magnetic recording medium are as follows.
(1) Low volatility.
(2) Low surface tension due to surface replenishment function.
(3) There is an interaction between the terminal polar group and the disc surface.
(4) High thermal and oxidative stability so that there is no decomposition or decrease during the period of use.
(5) It is chemically inert to metals, glass, and polymers, and does not generate abrasion powder on the head and guide.
(6) No toxicity or flammability.
(7) Excellent boundary lubrication characteristics.
(8) Dissolve in an organic solvent.

In recent years, ionic liquids have been attracting attention as one of the environmentally friendly solvents for synthesizing organic and inorganic materials in electricity storage materials, separation technology, catalyst technology and the like. Ionic liquids fall into the broad category of molten salts with a low melting point, but generally, they have a melting point of 100 ° C. or lower. Important properties of ionic liquids used as lubricants are their low volatility, non-flammability, thermal stability, and excellent dissolution performance.

For example, friction and wear on the surface of metals and ceramics may be reduced by using a certain ionic liquid as compared with conventional hydrocarbon-based lubricants. For example, an imidazole cation-based ionic liquid is synthesized by substituting with a fluoroalkyl group, and the tetrafluoroborate and hexafluorophosphate of alkylimidazolium are steel, aluminum, copper, single crystal SiO ₂ , silicon, and sialon ceramics. It has been reported that when used in (Si-Al-ON), it exhibits better tribological properties than cyclic phosphazene (X-1P) and PFPE. It has also been reported that ammonium-based ionic liquids have lower friction than base oils in the elastic fluid to boundary lubrication region. In addition, ionic liquids have been investigated for their effectiveness as additives to base oils, and chemical and tribochemical reactions have been studied to understand the lubrication mechanism. Lubricating properties at the molecular level There are few application examples as a magnetic recording medium that requires.

Among them, the alkylammonium perfluorooctanoate salt is a protonated ionic liquid (PIL), but it has been reported that it has a remarkable effect of reducing the friction of the magnetic recording medium as compared with the Z-DOL described above. (See, for example, Patent Documents 1 and 2 and Non-Patent Documents 5 to 7).
However, in the reaction shown in the following reaction formula (A), these perfluorocarboxylic acid ammonium salts have a weak interaction between cations and anions, and according to Le Chatelier's law, the equilibrium is on the left side at high temperatures. , It becomes a dissociated neutral compound and its thermal stability deteriorates. That is, at high temperatures, protons move and the equilibrium moves to a neutral substance and dissociates (see, for example, Non-Patent Document 8).

By the way, the limit of the surface recording density of the hard disk is said to be 1-2.5 Tb / in ² . Currently, the limit is approaching, but vigorous development of large-capacity technology is being continued on the premise of miniaturization of magnetic particles. Techniques for increasing capacity include reduction of effective flying height and introduction of Shingle Write (BMP).

In addition, as a next-generation recording technology, there is "heat-assisted magnetic recording (Heat Assisted Magnetic Recording)". FIG. 3 shows an outline of heat-assisted magnetic recording. An issue of this technique is deterioration of durability due to evaporation or decomposition of the lubricant on the surface of the magnetic layer because the recording portion is heated by a laser during recording / reproduction. Heat-assisted magnetic recording can be exposed to high temperatures, which are said to be 400 ° C or higher, for a short period of time, and are commonly used lubricants for thin-film magnetic recording media, such as perfluoropolyethers, such as Z-DOL and Z. -TETRAOL is concerned about its thermal stability.

Protonic ionic liquids are generally highly thermally stable substances for forming ions as described above. The equilibrium is shown in Scheme 1 below.

Here, HA stands for Bronsted acid and B stands for Bronsted base. The acid (HA) and the base (B) react as shown in Scheme 1 to form a salt (A ⁻ HB ⁺ ).
At this time, the dissociation constants _Ka1 and _Kb2 of the acid and the base, respectively, can be expressed as the following Scheme 2 in the form including the concentration.

K _a1 and K _b2 differ greatly depending on the substance, and in some cases, they have a large number of digits, which is inconvenient to handle. Therefore, they are often represented by a negative common logarithm. That is, as shown in the following Scheme 3, -log ₁₀ K _a1 = pK _a1 is defined, and an acid having a clearly smaller pK _a1 is more acidic.
Here, the difference ΔpKa between the acid dissociation constants of acids and bases will be discussed. The acid-base reaction is influenced by the acidity and basicity of each other (or the acidity of the conjugate acid), and the difference in acidity ΔpKa can be expressed in the following Scheme 3.

It can be seen that ΔpKa increases as the salt concentration [A ⁻ HB ⁺ ] increases with respect to the acid concentration and the base concentration.

Among them, Yoshizawa et al., When the difference in pKa between acid and base (ΔpKa) is 10 or more, proton transfer is likely to occur.
[AH] + [B] ⇔ [A ⁻ HB ⁺ ]
It has been reported that the equilibrium of the above equation shifts to the ion side (right side) and the stability is further increased (see, for example, Non-Patent Document 8). In addition, Watanabe et al. Used DBU (1,8-diazabicyclo [5,4,0] unde-7-sen as the base because the proton mobility and thermal stability of the protonic ionic liquid largely depend on ΔpKa. If so, it has been reported that the thermal stability of the ionic liquid is greatly improved by using an acid having a ΔpKa of 15 or more (see Non-Patent Document 9). Kondo et al. Also have a large ΔpKa. It has been reported that an octadecylammonium salt-based protonic ionic liquid of perfluorooctanesulfonate improves the durability of a magnetic recording medium (see Non-Patent Documents 10 and 3). Regarding the heat resistance of the ionic liquid. According to a recent report by Kondo et al., The decomposition temperature rises to a certain extent when ΔpKa is increased, but the decomposition temperature does not increase so much even if ΔpKa is increased above that (Non-Patent Document 11, Non-Patent Document 11, And 12). It has also been reported that a pyrrolidinium-based ionic liquid having a geminal dication may improve heat resistance as compared with a normal monocation ionic liquid (see Non-Patent Document 13). As described in Non-Patent Document 13, the relationship between the molecular structure constituting the structure and the physical or chemical properties is not well understood. The combination of a cation and an anion is an ionic liquid. It has a great influence on the physical or chemical properties. The anionic moiety is rich in variety, but the relationship is not clear unless it is a structurally similar proton (see, for example, Non-Patent Document 14). However, the stronger the hydrogen bonding force of the halogen (Cl>Br> I), the higher the viscosity of the liquid. However, the method of increasing the viscosity is not limited to this, and for example, the alkyl chain of the imidazole can be changed. It also affects melting point, surface tension, and thermal stability, but the effects of its anions have not been extensively studied. Therefore, depending on the combination of protons and anions, these physical or chemical properties. It is possible to change, but it is difficult to predict.

Also, when considering application to hard disks, as is the case with commercially available perfluoropolyether, solubility in fluorine-based solvents used in production lines (for example, DuPont's special solvent Bartrel) Is required. It should be noted that the fluorine-based solvent is suitably used as a solvent used as a lubricant in the hard disk production line because it is not necessary to make the production line explosion-proof. However, the solubility of compounds other than perfluoropolyether-based compounds in fluorine-based solvents is not very good, and therefore the use for hard disks has been limited despite the good lubrication characteristics.

Japanese Patent No. 2581090 Japanese Patent No. 2629725 International Publication No. 2014/10342 Pamphlet

Advances in Tribology Volume 2013, ArticleID 521086 C. M. Mate, Q. Dai, R.M. N. Payne, B. E. Knigge, and P. et al. Baumgart, "Will the number added up for sub-7-nm magnetic spacings? Future metrology issues for disk drive rubricants, overcoats, ove. 41, no. 2, pp. 626-631, 2005. B. Marchon and T.M. Olson, "Magnetic spacing trends: from LMR to PMR and beyond," IEEE Transitions on Magnetics, vol. 45, no. 10, pp. 3608-3611, 2009. J. Gui, "Tribology challenge for head-disk interface tower 1Tb / in2," IEEE Transitions on Magnetics, vol. 39, no. 2, pp. 716-721, 2003. Kondo, H.K. , Seto, J. et al. , Haga. S. , Ozawa, K.K. , (1989) Novell Lubricants for Magnetic Thin Film Media, Magnetic Soc. Japan, Vol. 13, Suppl. No. S1, pp. 213-218 Kondo, H.K. , Seki, A. , Watanabe, H. et al. , & Seto, J.M. , (1990). Frictional Properties of Novell Lubricants for Magnetic Thin Film Media, IEEE Trans. Magn. Vol. 26, No. 5, (Sep. 1990), pp. 2691-2693, ISSN: 0018-9464 Kondo, H.K. , Seki, A. , & Kita, A. , (1994a). Comparison of an Amide and Amine Salt as Friction Modifiers for a Magnetic Thin Film Medium. Tribology Trans. Vol. 37, No. 1, (Jan. 1994), pp. 99-105, ISSN: 0569-8197 Yoshizawa, M.M. , Xu, W. , Angel, C.I. A. , Ionic Liquids by Proton Transfer: Vapor pressure, Protonity, and the Relevance of ΔpKa from Aqueous Solutions, J. Mol. Am. Chem. Soc. , Vol. 125, pp. 15411-15419 (2003) Miran, M.M. S. , Kinoshita, H. et al. , Yasuda, T.M. , Susan, M.D. A. B. H. , Watanabe, M.D. , Physicochemical Properties Determined by ΔpKa for Protic Ionic Liquids Based on an Organic Super-strong Base with Various Bronsted Chem. Chem. Phys. , Vol 14, pp. 5178-5186 (2012) Hirofumi Kondo, Makiya Ito, Koki Hatsuda, Kyungsung Yun and Masayoshi Watanabe, "Novell Ionic Lubricant IEEE ENGEN ENGEN 49, NO. 7, pp. 3756-3759, JULY (2013) Hirofumi Kondo, Makiya Ito, Koki Hatsuda, Nobuo Tano, Kyungsung Yun and Masayoshi Watanabe, IEEE Dresden, Electronics, Electronics, Germany, Germany, and Electronics Engineers Hirofumi Kondo, Makiya Ito, Koki Hatsuda, Nobuo Tano, Kyungsung Yun and Masayoshi Watanabe, IEEE Trans. Magn. , 2014, Vol. 50, Issue 11, Article #: 3302504 Anderson, J. Mol. L. , Ding R. , Ellern A. , Armstrong D. W. , “Structure and Properties of High High Stability Geminal Scientific Iquids”, J. Mol. Am. Chem. Soc. , 2005, 127, 593-604. Dzyuba, S.M. V. Bartsch, R.M. A. , "Influence of Structural Variations in 1-Alkyl (aralkyl) -3-Methylimidazolium Hexafluorophosphates and Bis (trifluoromethylsulfonyl) imides on Physical Properties of the Ionic Liquids, Chem. Phys. Phys. Chem. 2002, 3, 161-166

The present invention has been proposed in view of such conventional circumstances, and is an ionic liquid having excellent lubricity even at high temperatures and excellent suitability for a production line of a magnetic recording medium, and is also excellent at high temperatures. Provided are a lubricant having excellent lubricity and excellent suitability for a production line of a magnetic recording medium, and a magnetic recording medium having excellent practical characteristics.

<1> Contains an ionic liquid having a conjugate base and a conjugate acid,
The conjugate acid has a group containing a linear hydrocarbon group having 6 or more carbon atoms.
The pKa of the acid that is the source of the conjugate base in acetonitrile is 10 or less.
Lubricant characterized in that the solubility of the ionic liquid in CF ₃ (CHF) ₂ CF ₂ CF ₃ is 0.1 part by mass or more with respect to 100 parts by mass of CF ₃ (CHF) ₂ CF ₂ CF _3. It is an agent.
<2> The conjugate acid is the following general formula (A), the following general formula (B), the following general formula (C), the following general formula (D), the following general formula (E), and the following general formula (F). The lubricant according to <1>, which is represented by any of the above.
However, in the general formula (A), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, and R ² represents either a hydrogen atom or a hydrocarbon group.
However, in the general formula (B), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms.
However, in the general formula (C), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms.
However, in the general formula (D), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, and R ² represents either a hydrogen atom or a hydrocarbon group.
However, in the general formula (E), R ³ represents a hydrocarbon group, R ⁴ represents either a hydrogen atom or a hydrocarbon group, and R ⁵ is a fluorinated hydrocarbon having 4 or more carbon atoms. Represents a group containing a fluorinated hydrocarbon group having 8 or more carbon atoms including hydrogen.
However, in the general formula (F), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, and n represents an integer of 1 or more and 3 or less.
<3> The above-mentioned <1> to <2>, wherein the conjugate base is represented by any of the following general formula (X), the following general formula (Y), and the following general formula (Z). It is a lubricant.
However, in the general formula (X), l represents an integer of 1 or more and 12 or less.
However, in the general formula (Y), n represents an integer of 1 or more and 12 or less.
However, in the general formula (Z), n represents an integer of 0 or more and 6 or less.
<4> Magnetism characterized by having a non-magnetic support, a magnetic layer on the non-magnetic support, and the lubricant according to any one of <1> to <3> on the magnetic layer. It is a recording medium.
<5> Having a conjugate base and a conjugate acid,
The conjugate acid has a group containing a linear hydrocarbon group having 6 or more carbon atoms.
The pKa of the acid that is the source of the conjugate base in acetonitrile is 10 or less.
Solubility _{CF 3 (CHF) 2 CF 2} CF 3 _are, with respect to _{CF 3 (CHF) 2 CF 2} CF 3 100 parts by weight, and ionic liquids, characterized in that at least 0.1 part by weight.
<6> The conjugate acid is the following general formula (A), the following general formula (B), the following general formula (C), the following general formula (D), the following general formula (E), and the following general formula (F). The ionic liquid according to <5>, which is represented by any of the above.
However, in the general formula (A), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, and R ² represents either a hydrogen atom or a hydrocarbon group.
However, in the general formula (B), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms.
However, in the general formula (C), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms.
However, in the general formula (D), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, and R ² represents either a hydrogen atom or a hydrocarbon group.
However, in the general formula (E), R ³ represents a hydrocarbon group, R ⁴ represents either a hydrogen atom or a hydrocarbon group, and R ⁵ is a fluorinated hydrocarbon having 4 or more carbon atoms. Represents a group containing a fluorinated hydrocarbon group having 8 or more carbon atoms including hydrogen.
However, in the general formula (F), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, and n represents an integer of 1 or more and 3 or less.
<7> The above-mentioned <5> to <6>, wherein the conjugate base is represented by any of the following general formula (X), the following general formula (Y), and the following general formula (Z). It is an ionic liquid.
However, in the general formula (X), l represents an integer of 1 or more and 12 or less.
However, in the general formula (Y), n represents an integer of 1 or more and 12 or less.
However, in the general formula (Z), n represents an integer of 0 or more and 6 or less.

According to the present invention, it is possible to improve thermal stability such as evaporation and thermal decomposition of the lubricant, and to maintain excellent lubricating characteristics for a long period of time. Further, even when the lubricant is used for the magnetic recording medium, the lubricating characteristics are excellent, and the practical characteristics such as running performance, wear resistance, and durability can be improved. Furthermore, it is possible to provide a lubricant that does not require the production line to be explosion-proof.

FIG. 1 is a graph showing changes and predictions of in-plane recording density of a hard disk drive. FIG. 2 is a roadmap of head media spacing (HMS) for the in-plane recording density of a hard disk. FIG. 3 is a schematic view showing heat-assisted magnetic recording. FIG. 4 is a cross-sectional view showing an example of a hard disk according to an embodiment of the present invention. FIG. 5 is a cross-sectional view showing an example of a magnetic tape according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail in the following order with reference to the drawings.
1. 1. Lubricant and ionic liquid 2. Magnetic recording medium 3. Example

<1. Lubricants and ionic liquids>
The lubricant shown as one embodiment of the present invention contains an ionic liquid having a conjugate acid and a conjugate base.
The ionic liquid shown as one embodiment of the present invention has a conjugate acid and a conjugate base.
In the ionic liquid, the conjugate acid has a group containing a hydrocarbon group. The hydrocarbon group is a linear hydrocarbon group having 6 or more carbon atoms. Here, the "linear hydrocarbon group having 6 or more carbon atoms" may be a partially fluorinated hydrocarbon group in which a part of hydrogen atoms bonded to carbon is replaced with a fluorine atom. Examples of the partially fluorinated hydrocarbon group include a fluorinated hydrocarbon group having 8 or more carbon atoms including a fluorinated hydrocarbon having 4 or more carbon atoms.
In the ionic liquid, the pKa of the acid that is the source of the conjugate base in acetonitrile is 10 or less.
The ionic _liquid solubility _{CF 3 (CHF) 2 CF 2} CF 3 _are, with respect to _{CF 3 (CHF) 2 CF 2} CF 3 100 parts by weight, is 0.1 parts by mass or more, 0.3 wt More than parts are preferable, and 0.5 parts by mass or more are more preferable. The upper limit of the solubility is not particularly limited and may be appropriately selected depending on the intended purpose, and an example thereof is 2.0 parts by mass.
The solubility is the solubility at 25 ° C.

The ionic liquid in the present embodiment has a conjugate acid and a conjugate base, and the pKa of the acid that is the source of the conjugate base in acetonitrile is 10 or less, so that it exhibits excellent thermal stability. be able to. Further, since the cation portion has a group containing a hydrocarbon group having 6 or more carbon atoms, it can also have excellent lubrication characteristics.
Further, since it dissolves in a certain amount in CF ₃ (CHF) ₂ CF ₂ CF ₃ which is often used as a fluorine-based solvent, a lubricant using a fluorine-based solvent can be produced. As a result, it is not necessary to make the production line of the magnetic recording medium explosion-proof.
Here, the lubricant containing the ionic liquid is usually used at a concentration of about 0.05% by mass or 0.1% by mass of the ionic liquid. Therefore, the solubility of the ionic liquid in a fluorine-based solvent needs to be 0.05% by mass or more, preferably 0.1% by mass or more. Further, depending on the usage conditions, higher solubility may be required. Furthermore, taking into account changes in the usage and storage conditions of the lubricant, 0.1% by mass or more [CF ₃ (CHF) ₂ CF ₂ CF ₃ 100 parts by mass and 0.1 parts by mass or more of ionic liquid ] Is required, and preferably 0.3% by mass or more is required.

As for the solubility in a solvent, there is an interpretation using the solubility parameter as a general method, and empirically, substances having similar solubility parameters tend to be easily mixed. However, since there is an application limit to the estimation of solubility based on the original solvability parameter value, these empirical values are often only for reference. In other words, this method is based on the regular solution theory, and the force acting between the solvent and the solute is modeled as only the intermolecular force, and the interaction that agglomerates the liquid molecule is considered to be only the intermolecular force. ing. However, it is rare that the actual solution is a regular solution, and forces other than intermolecular forces such as hydrogen bonds also act between the solvent and solute molecules, and whether the two components are mixed or phase-separated depends on those components. This is because it is determined thermodynamically by the difference between the mixed enthalpy and the mixed entropy. In the case of an ionic liquid, the molecule may contain ions, and its solubility in a solvent is quite difficult to predict.

The pKa is a strong acid of 10 or less, preferably 6.0 or less.
The lower limit of the pKa is not particularly limited and may be appropriately selected depending on the intended purpose, but the pKa is preferably −5.0 or higher.

Here, pKa in the present specification is an acid dissociation constant, which is an acid dissociation constant in acetonitrile.

<< Conjugate base >>
The conjugate base is not particularly limited as long as the pKa of the original acid in acetonitrile is 10 or less, and can be appropriately selected depending on the intended purpose. For example, it is represented by the following general formula (V). Conjugate base, conjugate base represented by the following general formula (W), conjugate base represented by the following general formula (X), conjugate base represented by the following general formula (Y), the following general formula (Z) Examples thereof include the represented conjugate base. Among these, the conjugate base represented by the following general formula (X), the conjugate base represented by the following general formula (Y), and the following general formula are used in that the solubility of the ionic liquid in a fluorine-based solvent can be increased. The conjugate base represented by (Z) is preferable, and the conjugate base represented by the following general formula (X) and the conjugate base represented by the following general formula (Y) are more preferable.
However, in the general formula (X), l represents an integer of 1 or more and 12 or less, an integer of 1 or more and 6 or less is preferable, and an integer of 3 or more and 6 or less is more preferable.
However, in the general formula (Y), n represents an integer of 1 or more and 12 or less, and an integer of 1 or more and 6 or less is preferable.
However, in the general formula (Z), n represents an integer of 0 or more and 6 or less.

Examples of the acid (HA) that is the source of the conjugated base include bis ((perfluoroalkyl) sulfonyl) imide [( _Cl F _{2l + 1} SO ₂ ) ₂ NH] (pKa = 0 to 0.3) and perfluorocyclopropane. Suruhoimido (pKa = -0.8), a perfluoroalkylsulfonic acid _{(C m F 2m + 1 SO} 3 H) (pKa = 0.7), tris (perfluoroalkanesulfonyl) methide compound _[(CF 3 _{SO 2) 3} CH] (pKa = -3.7), tricyanomethane (pKa = 5.1), inorganic acids [nitrate (pKa = 9.4), sulfuric acid (pKa = 8.7), etc.], tetrafluoroboric acid ( Bronsted acid, which is positioned as a super acid such as pKa = 1.8) and hexafluorophosphate, is preferable. These pKas are, for example, J. et al. Org. Chem. Vol. 76, No2, p. Introduced in 394.

<< Conjugate acid >>
The conjugate acid has a group containing a linear hydrocarbon group having 6 or more carbon atoms.
The number of carbon atoms of the hydrocarbon group is not particularly limited as long as it is 6 or more, and can be appropriately selected depending on the intended purpose, but 10 or more is preferable.

The upper limit of the carbon number of the linear hydrocarbon group having 6 or more carbon atoms is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of procuring raw materials, the carbon number of carbon atoms is not particularly limited. Is preferably 30 or less, more preferably 25 or less, and particularly preferably 20 or less. Since the hydrocarbon group has a long chain, the friction coefficient can be reduced and the lubrication characteristics can be improved.
As the group containing a linear hydrocarbon group having 6 or more carbon atoms, the linear hydrocarbon group having 6 or more carbon atoms is preferable.
However, if the number of carbon atoms is too large, the solubility in a fluorine-based solvent tends to decrease. Therefore, the carbon number of the hydrocarbon group takes into consideration the effect of reducing the coefficient of friction and the solubility in a fluorine-based solvent. Is preferably determined.

The hydrocarbon group may be linear, and may be either a saturated hydrocarbon group, an unsaturated hydrocarbon group having a double bond in part, or an unsaturated branched hydrocarbon group having a branch in part. Good. Among these, an alkyl group, which is a saturated hydrocarbon group, is preferable from the viewpoint of wear resistance. It is also preferable that the hydrocarbon group is a linear hydrocarbon group having no branching. Of course, it may be a hydrocarbon group having a branch in part.

Examples of the hydrocarbon group include a group represented by the following general formula (I), a group represented by the following general formula (II), and the like. The group represented by the general formula (II) corresponds to the partially fluorinated hydrocarbon group.
− (CH ₂ ) _l −CH ₃ General formula (I)
− (CH ₂ ) _m − (CF ₂ ) _n − CF ₃ General formula (II)
In the general formula (I), l represents an integer of 5 or more, preferably an integer of 9 or more and 29 or less, more preferably an integer of 9 or more and 24 or less, and particularly preferably an integer of 9 or more and 19 or less.
In the general formula (II), m represents an integer of 1 or more and 6 or less, and n represents an integer of 3 or more and 20 or less. However, m + n is 7 or more. m is preferably an integer of 1 or more and 3 or less, and n is preferably an integer of 5 or more and 10 or less.

Examples of the conjugate acid include a conjugate acid represented by the following general formula (A), a conjugate acid represented by the following general formula (B), a conjugate acid represented by the following general formula (C), and the following general formula (E). ) And the conjugate acid represented by the following general formula (F) are preferable because they are excellent in solubility in a fluorine-based solvent. Generally, it is common knowledge that when there are many hydrocarbon structures, the solubility in a fluorine-based solvent is low. However, the conjugate acid of the following general formula is unexpectedly excellent in solubility in a fluorine-based solvent.
However, in the general formula (A), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, and R ² represents either a hydrogen atom or a hydrocarbon group.
However, in the general formula (B), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms.
However, in the general formula (C), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms.
However, in the general formula (D), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, and R ² represents either a hydrogen atom or a hydrocarbon group.
However, in the general formula (E), R ³ represents a hydrocarbon group, R ⁴ represents either a hydrogen atom or a hydrocarbon group, and R ⁵ is a fluorinated hydrocarbon having 4 or more carbon atoms. Represents a group containing a fluorinated hydrocarbon group having 8 or more carbon atoms including hydrogen.
However, in the general formula (F), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, and n represents an integer of 1 or more and 3 or less.

Formula (A), the foregoing formula (B), wherein the general formula (C), and number of carbon atoms of the hydrocarbon group for R ¹ in the general formula (D), and the general formula (F) is As long as it is 6 or more, there is no particular limitation, and it can be appropriately selected depending on the intended purpose, but 10 or more is preferable.
The upper limit of the carbon number of the hydrocarbon group for R ^1, is not particularly limited and may be appropriately selected depending on the intended purpose, in terms of procurement of raw materials, the number of carbon atoms is preferably 30 or less , 25 or less is more preferable, and 20 or less is particularly preferable. Since the hydrocarbon group has a long chain, the friction coefficient can be reduced and the lubrication characteristics can be improved.
As the R ¹ , a linear hydrocarbon group having 6 or more carbon atoms is preferable.
However, if the number of carbon atoms is too large, the solubility in a fluorine-based solvent tends to decrease. Therefore, the carbon number of the hydrocarbon group takes into consideration the effect of reducing the coefficient of friction and the solubility in a fluorine-based solvent. Is preferably determined.

The hydrocarbon group in R ¹ may be linear, and even if it is a saturated hydrocarbon group, it is an unsaturated hydrocarbon group having a double bond in part or an unsaturated branched hydrocarbon having a branch in part. It may be any of the groups. Among these, an alkyl group, which is a saturated hydrocarbon group, is preferable from the viewpoint of wear resistance. It is also preferable that the hydrocarbon group is a linear hydrocarbon group having no branching.

Examples of the R ¹ include a group represented by the following general formula (III).
− (CH ₂ ) _l −CH ₃ General formula (III)
In the general formula (III), l represents an integer of 5 or more, preferably an integer of 9 or more and 29 or less, and more preferably an integer of 9 or more and 19 or less.

The hydrocarbon group in the R ³ and R ⁴ of the general formula (E) is not particularly limited and may be appropriately selected depending on the intended purpose, but a hydrocarbon group having 1 to 20 carbon atoms is preferable.

Wherein R ⁵ in the general formula (E) has a carbon number is a group containing a fluorinated hydrocarbon group having 8 or more carbon atoms containing 4 or more fluorinated hydrocarbons. By having the group according to the general formula (E), the solubility in a fluorine-based solvent is improved.
As the R ^5, preferably a group represented by the following general formula (IV).
− (CH ₂ ) _m − (CF ₂ ) _n − CF ₃ General formula (IV)
In the general formula (IV), m represents an integer of 1 or more and 6 or less, and n represents an integer of 3 or more and 20 or less. However, m + n is 7 or more. m is preferably an integer of 1 or more and 3 or less, and n is preferably an integer of 7 or more and 10 or less. If the number of carbon atoms in the fluorinated carbon is too long, the solubility in the solvent is reduced, and the length is determined by other components in the molecule.

<< Preferable example of ionic liquid >>
Examples of the ionic liquid include an ionic liquid represented by the following general formula (1), an ionic liquid represented by the following general formula (2), an ionic liquid represented by the following general formula (3), and the following general formula (4). The ionic liquid represented by the following general formula (5), the ionic liquid represented by the following general formula (5), and the ionic liquid represented by the following general formula (6) are preferable.
However, in the general formula (1), A ⁻ represents a conjugate base, R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, and R ² represents a hydrogen atom and a hydrogen atom. Represents one of the hydrocarbon groups.
However, in the general formula (2), A ⁻ represents a conjugate base, and R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms.
However, in the general formula (3), A ⁻ represents a conjugate base, and R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms.
However, in the general formula (4), A ⁻ represents a conjugate base, R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, and R ² represents a hydrogen atom and a hydrogen atom. Represents one of the hydrocarbon groups.
However, in the general formula (5), A ⁻ represents a conjugated base, R ³ represents a hydrocarbon group, R ⁴ represents either a hydrogen atom or a hydrocarbon group, and R ⁵ represents a hydrocarbon group. Represents a group containing a fluorinated hydrocarbon group having 4 or more carbon atoms and containing a fluorinated hydrocarbon group having 8 or more carbon atoms.
However, in the general formula (6), A ⁻ represents a conjugate base, R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, and n represents 1 or more and 3 or less. Represents an integer.

As the ionic liquid represented by the general formula (1), an ionic liquid represented by the following general formula (1-1) and an ionic liquid represented by the following general formula (1-2) are preferable.

However, in the general formula (1-1), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, and R ² represents either a hydrogen atom or a hydrocarbon group. Represented, l represents an integer of 1 or more and 12 or less.

As the ionic liquid represented by the general formula (2), an ionic liquid represented by the following general formula (2-1) and an ionic liquid represented by the following general formula (2-2) are preferable.
However, in the general formula (2-1), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, and l represents an integer of 1 or more and 12 or less.
However, in the general formula (2-2), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, and n represents an integer of 1 or more and 12 or less.

As the ionic liquid represented by the general formula (4), an ionic liquid represented by the following general formula (4-1) and an ionic liquid represented by the following general formula (4-2) are preferable.
However, in the general formula (4-1), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, and R ² represents either a hydrogen atom or a hydrocarbon group. Represented, l represents an integer of 1 or more and 12 or less.
However, in the general formula (4-2), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, and R ² represents either a hydrogen atom or a hydrocarbon group. Represented, n represents an integer of 1 or more and 12 or less.

As the ionic liquid represented by the general formula (5), an ionic liquid represented by the following general formula (5-1) and an ionic liquid represented by the following general formula (5-2) are preferable.
However, in the general formula (5-1), R ³ represents a hydrocarbon group, R ⁴ represents either a hydrogen atom or a hydrocarbon group, and R ⁵ is fluorine having 4 or more carbon atoms. It represents a group containing a fluorinated hydrocarbon group having 8 or more carbon atoms including a hydrocarbon, and n represents an integer of 1 or more and 12 or less.
However, in the general formula (5-2), R ³ represents a hydrocarbon group, R ⁴ represents either a hydrogen atom or a hydrocarbon group, and R ⁵ is fluorine having 4 or more carbon atoms. It represents a group containing a fluorinated hydrocarbon group having 8 or more carbon atoms including a hydrocarbon, and l represents an integer of 1 or more and 12 or less.

As the ionic liquid represented by the general formula (6), the ionic liquid represented by the following general formula (6-1) is preferable.
However, in the general formula (6-1), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, n represents an integer of 1 or more and 3 or less, and l is. Represents an integer of 1 or more and 12 or less.

The preferred range of R ¹ in the general formula of the ionic liquid is the same as the preferred range of R ^{1 in} the corresponding general formula of the conjugate acid.
The preferred range of R ² in the general formula of the ionic liquid is the same as the preferred range of R ^{2 in} the corresponding general formula of the conjugate acid.
The preferred range of R ³ in the general formula of the ionic liquid is the same as the preferred range of R ^{3 in} the corresponding general formula of the conjugate acid.
The preferred range of R ⁴ in the general formula of the ionic liquid is the same as the preferred range of R ^{4 in} the corresponding general formula of the conjugate acid.
The preferred range of R ⁵ in the general formula of the ionic liquid is the same as the preferred range of R ^{5 in} the corresponding general formula of the conjugate acid.
The preferred range of l in the general formula of the ionic liquid is the same as the preferred range of l in the corresponding general formula of the conjugate base.
The preferred range of n in the conjugate base of the general formula of the ionic liquid is the same as the preferred range of n in the corresponding general formula of the conjugate base.

The method for synthesizing the ionic liquid is not particularly limited and may be appropriately selected depending on the intended purpose. For example, various ionic liquids are synthesized by referring to the methods described in the following examples. be able to.

As the lubricant in the present embodiment, the above-mentioned ionic liquid may be used alone, or may be used in combination with a conventionally known lubricant. For example, it can be used in combination with a long-chain carboxylic acid, a long-chain carboxylic acid ester, a perfluoroalkylcarboxylic acid ester, a carboxylic acid perfluoroalkyl ester, a perfluoroalkylcarboxylic acid perfluoroalkyl ester, a perfluoropolyether derivative, or the like. It is possible.

Further, in order to maintain the lubricating effect under severe conditions, an extreme pressure agent may be used in combination at a mass ratio of about 30:70 to 70:30. When a metal contact occurs partially in the boundary lubrication region, the extreme pressure agent reacts with the metal surface by the frictional heat associated therewith to form a reaction product film, thereby performing a friction / wear prevention action. It is a thing. As the extreme pressure agent, for example, a phosphorus-based extreme pressure agent, a sulfur-based extreme pressure agent, a halogen-based extreme pressure agent, an organometallic extreme pressure agent, a composite type extreme pressure agent, or the like can be used.

In addition, a rust preventive may be used in combination if necessary. The rust preventive may be any one that can be usually used as a rust preventive for this type of magnetic recording medium. For example, phenols, naphthols, quinones, heterocyclic compounds containing nitrogen atoms, and oxygen atoms. Examples thereof include a heterocyclic compound containing a sulfur atom and a heterocyclic compound containing a sulfur atom. The rust preventive may be mixed and used as a lubricant, but a magnetic layer is formed on a non-magnetic support, a rust preventive layer is applied on the upper portion, and then a lubricant layer is applied. As such, the coating may be divided into two or more layers.

Further, as the solvent of the lubricant, for example, alcohol-based solvents such as isopropyl alcohol (IPA) and ethanol can be used alone or in combination. For example, it can also be used by mixing a hydrocarbon solvent such as normal hexane or a fluorine solvent.
As the solvent, a fluorine-based solvent is preferable. Examples of the fluorine-based solvent include hydrofluoroethers [for example, C ₃ F ₇ OCH ₃ , C ₄ F ₉ OCH ₃ , C ₄ F ₉ OC ₂ H ₅ , C ₂ F ₅ CF (OCH ₃ ) C ₃ F. ₇ , CF ₃ (CHF) ₂ CF ₂ CF ₃ ] and the like, but an alcohol such as IPA, ethanol or methanol may be mixed and used.
The fluorine-based solvent may be a commercially available product. Examples of the commercially available products include Novec ^TM 7000, 7100, 7200, 7300, 71IPA manufactured by 3M, Vertrel XF and XP10 manufactured by Mitsui-DuPont Fluorochemical Co., Ltd. and the like.

<2. Magnetic recording medium>
Next, the magnetic recording medium using the above-mentioned lubricant will be described. The magnetic recording medium shown as an embodiment of the present invention has at least a magnetic layer on a non-magnetic support, and has the above-mentioned lubricant in the magnetic layer.

The lubricant in the present embodiment can be applied to a so-called metal thin film type magnetic recording medium in which a magnetic layer is formed on the surface of a non-magnetic support by a method such as vapor deposition or sputtering. It can also be applied to a magnetic recording medium having a structure in which a base layer is interposed between a non-magnetic support and a magnetic layer. Examples of such a magnetic recording medium include magnetic disks and magnetic tapes.

FIG. 4 is a cross-sectional view showing an example of a hard disk. This hard disk has a structure in which a substrate 11, a base layer 12, a magnetic layer 13, a carbon protective layer 14, and a lubricant layer 15 are sequentially laminated.

Further, FIG. 5 is a cross-sectional view showing an example of the magnetic tape. This magnetic tape has a structure in which a back coat layer 25, a substrate 21, a magnetic layer 22, a carbon protective layer 23, and a lubricant layer 24 are sequentially laminated.

In the magnetic disk shown in FIG. 4, the non-magnetic support corresponds to the substrate 11 and the base layer 12, and in the magnetic tape shown in FIG. 5, the non-magnetic support corresponds to the substrate 21. When a rigid substrate such as an Al alloy plate or a glass plate is used as the non-magnetic support, even if an oxide film such as alumite treatment or a Ni-P film is formed on the surface of the substrate to harden the surface. Good.

The magnetic layers 13 and 22 are formed as a continuous film by techniques such as plating, sputtering, vacuum deposition, and plasma CVD. Examples of the magnetic layers 13 and 22 include metals such as Fe, Co, and Ni, Co—Ni alloys, Co—Pt alloys, Co—Ni—Pt alloys, Fe—Co alloys, and Fe—Ni alloys. In-plane magnetization recording metal magnetic film composed of Fe-Co-Ni based alloy, Fe-Ni-B based alloy, Fe-Co-B based alloy, Fe-Co-Ni-B based alloy, etc., and Co-Cr based alloy. Vertical magnetization recording metal magnetic thin films such as thin films and Co—O thin films are exemplified.

In particular, when forming an in-plane magnetization recording metal magnetic thin film, a non-magnetic material such as Bi, Sb, Pb, Sn, Ga, In, Ge, Si, or Tl is previously formed as the base layer 12 on the non-magnetic support. In addition, the metallic magnetic material is vapor-deposited or sputtered from the vertical direction to diffuse these non-magnetic materials into the magnetic metal thin film, eliminating the orientation, ensuring in-plane isotropic property, and improving the coercive force. You may do so.

Further, hard protective layers 14 and 23 such as a carbon film, a diamond-like carbon film, a chromium oxide film, and a SiO ₂ film may be formed on the surfaces of the magnetic layers 13 and 22.

As a method of holding the above-mentioned lubricant in such a metal thin film type magnetic recording medium, as shown in FIGS. 4 and 5, the top surface is on the surfaces of the magnetic layers 13 and 22 and the surfaces of the protective layers 14 and 23. There is a method of coating. The coating amount of the lubricant is ^{preferably 0.1mg / m 2 ~100mg / m 2} , more preferably ^{0.5mg / m 2 ~30mg / m 2} , 0.5mg / m 2 ~ It is particularly preferably 20 mg / m ² .

Further, as shown in FIG. 5, in the metal thin film type magnetic tape, a back coat layer 25 may be formed as needed in addition to the metal magnetic thin film which is the magnetic layer 22.

The backcoat layer 25 is formed by adding carbon-based fine powder for imparting conductivity to the resin binder and an inorganic pigment for controlling the surface roughness. In the present embodiment, the above-mentioned lubricant may be contained in the back coat layer 25 by internal addition or top coat. Further, the above-mentioned lubricant may be contained in both the magnetic layer 22 and the back coat layer 25 by internal addition or top coating.

Further, as another embodiment, the lubricant can be applied to a so-called coating type magnetic recording medium in which a magnetic coating film is formed as a magnetic layer by applying a magnetic coating material to the surface of a non-magnetic support. is there. In the coating type magnetic recording medium, any conventionally known magnetic powder, resin binder, or the like constituting the non-magnetic support or the magnetic coating film can be used.

For example, as the non-magnetic support, for example, a polymer support formed of a polymer material such as polyesters, polyolefins, cellulose derivatives, vinyl resins, polyimides, polyamides, polycarbonate and the like. Examples thereof include a metal substrate made of an aluminum alloy, a titanium alloy, etc., a ceramics substrate made of alumina glass, a glass substrate, and the like. Further, the shape is not limited in any way, and any shape such as a tape shape, a sheet shape, a drum shape, or the like may be used. Further, the non-magnetic support may be surface-treated so as to form fine irregularities in order to control its surface property.

Examples of the magnetic powder include ferromagnetic iron oxide-based particles such as γ-Fe ₂ O ₃ and cobalt-adhered γ-Fe ₂ O ₃ , ferromagnetic chromium dioxide-based particles, metals such as Fe, Co, and Ni, and these. Examples thereof include ferromagnetic metal particles made of the contained alloy, hexagonal plate-shaped hexagonal ferrite fine particles, and the like.

Examples of the resin binder include polymers such as vinyl chloride, vinyl acetate, vinyl alcohol, vinylidene chloride, acrylic acid ester, methacrylic acid ester, styrene, butadiene, and acrylonitrile, or copolymers obtained by combining two or more of these, polyurethane. Examples thereof include resins, polyester resins, and epoxy resins. Hydrophilic polar groups such as carboxylic acid groups, carboxyl groups, and phosphoric acid groups may be introduced into these binders in order to improve the dispersibility of the magnetic powder.

In addition to the magnetic powder and the resin binder, a dispersant, an abrasive, an antistatic agent, a rust preventive, and the like may be added to the magnetic coating film.

As a method of holding the above-mentioned lubricant in such a coating type magnetic recording medium, a method of internally adding the above-mentioned lubricant in the magnetic layer constituting the magnetic coating film formed on the non-magnetic support, the said magnetism. There is a method of top-coating the surface of the layer, or a combination of both of them. When the lubricant is internally added to the magnetic coating film, it is added in the range of 0.2 parts by mass to 20 parts by mass with respect to 100 parts by mass of the resin binder.

Further, in the case of top coat the lubricant on the surface of the magnetic layer preferably has an applied amount is ^{0.1mg / m 2 ~100mg / m 2} , 0.5mg / m 2 ~20mg / m and more preferably ^2. When the lubricant is top-coated, the ionic liquid may be dissolved in a solvent and the obtained solution may be applied or sprayed, or a magnetic recording medium may be immersed in the solution.

The magnetic recording medium to which the lubricant is applied according to the present embodiment exhibits excellent running performance, wear resistance, durability, and the like due to the lubricating action, and can further improve the thermal stability.

<3. Example>
Hereinafter, specific examples of the present invention will be described. In this example, an ionic liquid was synthesized to prepare a lubricant containing the ionic liquid. Then, first, the solubility in Bartlel [CF ₃ (CHF) ₂ CF ₂ CF ₃ ], which is a fluorine-based solvent, was investigated. The lubricant solution was applied to the surfaces of a magnetic disk and a magnetic tape, and the disk durability and tape durability were evaluated, respectively. The production of the magnetic disk, the disk durability test, the production of the magnetic tape, and the tape durability test were carried out as follows. The present invention is not limited to these examples.

<Manufacturing of magnetic disks>
For example, according to International Publication No. 2005/068589, a magnetic thin film was formed on a glass substrate to prepare a magnetic disk as shown in FIG. Specifically, a chemically strengthened glass disk made of aluminum silicate glass having an outer diameter of 65 mm, an inner diameter of 20 mm, and a disk thickness of 0.635 mm is prepared, and the surface thereof is polished so that Rmax is 4.8 nm and Ra is 0.43 nm. did. The glass substrate was ultrasonically cleaned in pure water and isopropyl alcohol (IPA) having a purity of 99.9% or more for 5 minutes, left in IPA saturated steam for 1.5 minutes, and then dried. did.

On this substrate 11, a NiAl alloy (Ni: 50 mol%, Al: 50 mol%) thin film was formed as a seed layer by a DC magnetron sputtering method at 30 nm, and a CrMo alloy (Cr: 80 mol%, Mo: 20 mol%) was used as the base layer 12. %) A thin film of CoCrPtB alloy (Co: 62 mol%, Cr: 20 mol%, Pt: 12 mol%, B: 6 mol%) was sequentially formed so as to have a thickness of 8 nm and a magnetic layer 13 of 15 nm.

Next, a carbon protective layer 14 made of amorphous diamond-like carbon was formed into a 5 nm film by a plasma CVD method, and the disk sample was ultrasonically placed in a washer in isopropyl alcohol (IPA) having a purity of 99.9% or more for 10 minutes. It was washed to remove impurities on the disk surface and then dried. Then, in an environment of 25 ° C. and 50% relative humidity (RH), the lubricant layer 15 was formed at about 1 nm by applying the ionic liquid n-hexane and ethanol in a mixed solvent by a dip coating method on the disk surface.

<Measurement of thermal stability>
For TG / DTA measurement, EXSTAR6000 manufactured by Seiko Instruments Inc. is used, and measurement is performed in the temperature range of 30 ° C.-600 ° C. at a temperature rise rate of 10 ° C./min while introducing air at a flow rate of 200 ml / min. went.

<Disc durability test>
After mounting the hard disk on the rotating spindle with a tightening torque of 14.7 Ncm using a commercially available strain gauge disc friction / wear tester, the center of the air bearing surface on the inner peripheral side of the hard disk of the head slider is the hard disk. A CSS durability test was conducted by mounting a head slider on the hard disk so that it was 17.5 mm from the center. The head used for this measurement is an IBM 3370 type in-line head, the slider material is Al ₂ O _3- TiC, and the head load is 63.7 mN. In this test, the maximum value of the frictional force was monitored for each CSS (Control, Start, Stop) in an environment of clean cleanliness of 100 and 25 ° C. and 60% RH. The number of times the friction coefficient exceeded 1.0 was taken as the result of the CSS durability test. In the result of the CSS durability test, when it exceeds 50,000 times, it is displayed as ">50,000". Further, in order to examine the heat resistance, a CSS durability test after performing a heating test at a temperature of 200 ° C. for 3 minutes was also performed in the same manner.

<Manufacturing of magnetic tape>
A magnetic tape having a cross-sectional structure as shown in FIG. 5 was produced. First, Co was adhered to a substrate 21 made of Toray's Mictron (aromatic polyamide) film having a thickness of 5 μm by an oblique vapor deposition method to form a magnetic layer 22 made of a ferromagnetic metal thin film having a film thickness of 100 nm. Next, a carbon protective layer 23 made of diamond-like carbon having a diameter of 10 nm was formed on the surface of the ferromagnetic metal thin film by a plasma CVD method, and then cut into a width of 6 mm. An ionic liquid dissolved in IPA was applied onto the carbon protective layer 23 so as to have a film thickness of about 1 nm to form a lubricant layer 24, and a sample tape was prepared.

<Tape durability test>
For each sample tape, the still durability under a temperature of -5 ° C and a temperature of 40 ° C and 30% RH, and the coefficient of friction and shuttle durability under a temperature of -5 ° C and a temperature of 40 ° C and 90% RH. Measurements were made. For still durability, the decay time until the output in the pause state decreased by -3 dB was evaluated. The shuttle durability was evaluated by the number of shuttle runs until the output decreased by 3 dB after repeated shuttle running for 2 minutes each time. Further, in order to examine the heat resistance, a durability test after performing a heating test at a temperature of 100 ° C. for 10 minutes was also performed in the same manner.

The ionic liquid in the present embodiment has a conjugate base and a conjugate acid, and the pKa of the acid that is the source of the conjugate base in acetonitrile is 10 or less. Further, it is preferable to have a group containing a hydrocarbon group having 6 or more carbon atoms in the cation moiety. The effect on the thermal stability of such an ionic liquid and the durability of a magnetic recording medium using the ionic liquid was investigated. Furthermore, the solubility in a fluorine-based solvent was investigated.

(Example 1A)
<Synthesis of bis (nonaflate butane sulfonyl) imide-6-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecene>
The synthesis of bis (nonafluorobutanesulfonyl) imide-6-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecene was carried out according to the following scheme.

6-Octadecyl-1,8-diazabicyclo [5.4.0] -7-undecene (6-octadecyl DBU) is described in the non-patent document of Matsumura et al. Matsumura, H. et al. Nishiguchi, M.M. Okada, and S. Yoneda, J.M. Heterocyclic Chem. pp. 885-887, Vol / 23. It was synthesized according to Issue 3 (1986)].

11.84 g of a 30% aqueous solution of bis (nonafluorobutanesulfonyl) imide was added to 2.47 g of the obtained 6-octadecyl DBU ethanol solution, and the mixture was stirred at room temperature for 1 hour and then heated to reflux for 1 hour. After removing the solvent, it was dissolved in dichloromethane and washed thoroughly with water. The organic layer was dried over anhydrous sodium sulfate, and the solvent was removed. Vacuum drying was performed at 90 ° C. for 3 days to obtain 5.55 g of colorless liquid bis (nonafluorobutanesulfonyl) imide-6-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecene. Yield 92.2%

Here, the measurement of FTIR in the present specification was carried out by the permeation method using the FT / IR-460 manufactured by JASCO Corporation and the KBr plate method or the KBr tablet method. The resolution at that time is 4 cm ^-1 .

^{1 1} H-NMR and ¹³ C-NMR spectra were measured by a Varian MercuryPlus 300 nuclear magnetic resonance apparatus (manufactured by Varian). ^{1 1} H-NMR chemical shifts are expressed in ppm as a comparison with internal standards (TMS or deuterated solvent peaks at 0 ppm). The splitting pattern was shown with the singlet as s, the doublet as d, the triplet as t, the multiplet as m, and the Broad Peak as br.

The FTIR absorption of the product and its attribution are shown below.
1042 cm ^-1 is SNS inverse symmetric expansion and contraction vibration, 1091 cm ^-1 is SO ₂ symmetric expansion and contraction vibration, 1164 cm ^-1 is CF ₂ symmetric expansion and contraction vibration, 1360 cm ^-1 is SO ₂ coupling inverse symmetric expansion and contraction vibration, 1633 cm ^-1 is stretching vibration of C = N, symmetric stretching vibration of CH ₂ in 2848cm ^-1, antisymmetric stretching vibration of CH ₂ was observed in 2920 cm ^-1.

The peaks of proton ( ¹ H) NMR and carbon ( ¹³ C) NMR in CDCl ₃ are shown below.
^{1 1} H-NMR (CDCl ₃ , δppm); 0.853 (t, 3H, J = 6.6Hz), 1.150-1.470 (m, 32H), 1.490-1.750 (m, 6H) ), 1.750-1.890 (m, 2H), 1.960-2.120 (2H, m), 2.700-2.800 (1H, m), 3.400-3.480 (m) , 2H), 3.507 (t, J = 6.0Hz, 2H), 3.550-3.650 (m, 2H), 7.690 (brs, 1H)
¹³ C-NMR (CDCl ₃ , δppm); 14.085, 19.199, 22.663, 25.502, 26.143, 27.105, 28.234, 28.982, 29.226, 29.349 , 29.394, 29.501, 29.593, 29.639, 29.684, 31.913, 38.659, 43.375, 49.664, 53.953, 168.258

From these spectra, the product was identified as bis (nonaflatebutanesulfonyl) imide-6-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecene.
The acid [bis (nonafluorobutanesulfonyl) imide] that is the source of the conjugate base in bis (nonafluorobutanesulfonyl) imide-6-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecene. The pKa in acetonitrile is 0.0.

(Example 2A)
<Synthesis of bis (nonaflate butane sulfonyl) imide-8-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenium>
The synthesis of bis (nonaflatebutanesulfonyl) imide-8-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenium was carried out according to the following scheme.

7.13 g of DBU and 17.28 g of octadecyl bromide were added to the flask and heated on a hot plate at 250 ° C. for 3 hours. It crystallized when returned to room temperature. The crystals were recrystallized from ethyl acetate to obtain 19.06 g of colorless crystals 8-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenium bromide. Yield 83.8%.

The peaks of proton ( ¹ H) NMR and carbon ( ¹³ C) NMR of the obtained compound in CDCl ₃ are shown below.
^{1 1} H-NMR (CDCl ₃ , δppm); 0.826 (t, 3H, J = 6.9Hz), 1.180-1.310 (m, 30H), 1.530-1.640 (m, 2H) ), 1.710-1.810 (m, 6H), 2.100-2.170 (m, 2H), 2.850-2.910 (2H, m), 3.452-3.505 (m) , 2H), 3.613 (t, J = 7.5Hz, 2H), 3.650-3.750 (m, 4H)
¹³ C-NMR (CDCl ₃ , δppm); 13.918, 20.114, 22.465, 22.984, 25.930, 26.357, 28.234, 28.570, 28.982, 29.135 , 29.242, 29.303, 29.394, 29.440, 29.486, 31.699, 47.252, 49.328, 54.182, 55.387, 166.259

From these spectra, it was identified that the product was 8-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenium bromide.

2.52 g of 8-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenium bromide is dissolved by heating water, and an aqueous solution of 3.07 g of bis (nonafluorobutanesulfonyl) imide lithium salt is dissolved. Was added. After stirring at room temperature for 1 hour, heating and reflux were performed for 1 hour. After cooling, the reaction solution was extracted with dichloromethane and washed thoroughly with water until the silver nitrate test was negative. The organic layer is dried over anhydrous sodium sulfate, the solvent is removed, and the colorless liquid bis (nonaflatebutanesulfonyl) imide-8-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenium 4.83 g. Got Yield 94.4%.

The FTIR absorption of the product and its attribution are shown below.
1072 cm ^-1 is the inverse symmetric expansion and contraction vibration of SNS, 1163 cm ^-1 is the symmetrical expansion and contraction vibration of CF ₂ , 1352 cm ^-1 is the inverse symmetric expansion and contraction vibration of SO ₂ coupling, 1469 cm ^-1 is the variable angle vibration of CH ₂ and 1626 cm ^-1 . symmetric stretching vibration of C = N, symmetric stretching vibration of CH ₂ in 2852cm ^-1, antisymmetric stretching vibration of CH ₂ were observed to 2922cm ^-1.

The peaks of proton ( ¹ H) NMR and carbon ( ¹³ C) NMR in CDCl ₃ are shown below.
^{1 1} H-NMR (CDCl ₃ , δppm); 0.854 (t, 3H, J = 6.6Hz), 1.170-1.320 (m, 30H), 1.520-1.610 (m, 2H) ), 1.650-1.810 (m, 6H), 2.030-2.130 (m, 2H), 2.750-2.800 (2H, m), 3.380-3.440 (m) , 2H), 3.450-3.540 (m, 4H), 3.580-3.630 (m, 2H)
¹³ C-NMR (CDCl ₃ , δppm); 14.055, 19.855, 22.663, 22.953, 25.838, 26.433, 28.204, 28.433, 28.254, 29.059 , 29.333, 29.394, 29.455, 29.562, 29.623, 29.669, 31.898, 46.977, 48.992, 54.121, 55.189, 166.381

From these spectra, the product was identified as bis (nonaflatebutanesulfonyl) imide-8-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenium.
The acid [bis (nonafluoromethanesulfonyl) imide] that is the source of the conjugate base in bis (nonafluorobutanesulfonyl) imide-8-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenium The pKa in acetonitrile is 0.0.

(Example 3A)
<Synthesis of nonaflate butane sulfonic acid-8-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenium>
The synthesis of nonaflate butane sulfonic acid -8-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenium was carried out according to the following scheme.

3.11 g of 8-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenium bromide synthesized in the same manner as in Example 2A was dissolved in warm water, and potassium nonafluorobutanesulfonic acid salt 2. 17 g of aqueous solution was added. After stirring at room temperature for 1 hour, the mixture was heated under reflux for 1 hour. After cooling, the reaction solution was extracted with dichloromethane and washed thoroughly with water until the silver nitrate test was negative. The organic layer was dried over anhydrous sodium sulfate and the solvent was removed to obtain 4.33 g of a colorless liquid nonaflate butanesulfonic acid-8-octadecyl-1,8-diazabicyclo [5.4.0] -7-undeceneium. .. Yield 95.9%.

The FTIR absorption of the product and its attribution are shown below.
1132 cm ^-1 is SO ₂ symmetric expansion and contraction vibration, 1230 cm ^-1 is CF symmetric expansion and contraction vibration, 1259 cm ^-1 is SO ₂ coupling inverse symmetric expansion and contraction vibration, 1468 cm ^-1 is CH ₂ eccentric vibration, 2854 cm ^-1 is CH. ₂ symmetric stretching vibration, antisymmetric stretching vibration of CH ₂ was observed in 2924 cm ^-1.

The peaks of proton ( ¹ H) NMR and carbon ( ¹³ C) NMR in deuterated chloroform are shown below.
^{1 1} H-NMR (CDCl ₃ , δppm); 0.850 (t, 3H, J = 6.6Hz), 1.170-1.320 (m, 30H), 1.520-1.620 (m, 2H) ), 1.670-1.820 (m, 6H), 2.040-2.140 (m, 2H), 2.790-2.850 (2H, m), 3.417-3.470 (m) , 2H), 3.490-3.600 (m, 4H), 3.620-3.670 (m, 2H)
¹³ C-NMR (CDCl ₃ , δppm); 14.040, 19.992, 22.618, 23.045, 25.899, 26.464, 28.341, 28.494, 28.555, 29.089 , 29.288, 29.379, 29.440, 29.532, 29.593, 29.639, 31.852, 46.993, 49.038, 54.105, 55.220, 166.488

From these spectra, the product was identified as nonaflate butane sulfonic acid -8-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenium.
The pKa of the acid (nonafluorobutanesulfonic acid) that is the source of the conjugate base in nonaflatebutanesulfonic acid-8-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenium in acetonitrile is , 0.7.

(Example 4A)
<Synthesis of bis (nonaflate butane sulfonyl) imide-N-butyl-N-octadecylpyrrolidinium>
The synthesis of bis (nonafluorobutanesulfonyl) imide-N-butyl-N-octadecylpyrrolidinium was carried out according to the following scheme.

52.4 g of bromooctadecane and 8.75 g of potassium hydroxide were added to acetonitrile, and 11.09 g of pyrrolidine was added. Then, heating and refluxing was carried out for 24 hours. After filtering the crystals, the solvent of the organic layer was removed, and silica gel column chromatography was performed using a mixed solvent of hexane and ethyl acetate to purify the crystals to obtain 44.05 g of octadecylpyrrolidin. The purity by gas chromatography was 99.0% or more.

5.04 g of octadecylpyrrolidine and 2.15 g of bromobutane were added to acetonitrile and heated under reflux for 69 hours for reaction. After completion of the reaction, the crystals cooled and precipitated were filtered and vacuum dried at 50 ° C. to obtain 5.85 g of colorless crystals of N-butyl-N-octadecylpyrrolidinium bromide. Yield 81.0%.

2.15 g of N-butyl-N-octadecylpyrrolidinium bromide is dissolved in warm water, 2.88 g of a mixed solution of ethanol / water of bis (nonafluorobutanesulfonyl) imide potassium salt is added, and the mixture is stirred at room temperature for 1 hour and then heated. Reflux was performed for 1 hour. After dissolving the reaction product in dichloromethane, wash it thoroughly with water until the silver nitrate test becomes negative, dry the organic layer with anhydrous sodium sulfate, remove the solvent, and vacuum dry at 100 ° C. for 5 hours to 4.05 g. A pale yellow waxy bis (nonafluorobutanesulfonyl) imide-N-butyl-N-octadecylpyrrolidinium was obtained. Yield 90.3%.

The FTIR absorption of the product and its attribution are shown below.
Antisymmetric stretching vibration of SNS to ^{1072cm -1, 1134cm -1, 1165cm -1} , 1196cm -1, symmetric stretching vibration of CF ₂ to 1232cm ^-1, antisymmetric stretching vibration of SO ₂ to 1352cm ^-1, to 1469cm ^-1 deformation vibration of CH _2, symmetric stretching vibration of CH ₂ in 2852cm ^-1, antisymmetric stretching vibration of CH ₂ were observed to 2922cm ^-1.

The peaks of proton ( ¹ H) NMR and carbon ( ¹³ C) NMR in deuterated methanol are shown below.
^{1 1} H-NMR (δppm); 0.890 (t, 3H, J = 6.9Hz), 1.004 (t, 3H, J = 6.9Hz), 1.220-1.470 (m, 32H) , 1.625-1.770 (m, 4H), 2.000-2.140 (m, 4H), 3.221-3.288 (m, 4H), 3.489-3.536 (m, 4H)
¹³ C-NMR (δppm); 13.880, 14.444, 20.733, 22.824, 23.740, 24.213, 26.212, 27.418, 30.181, 30.486, 30. 532, 30.608, 30.576, 33.081, 60.783, 60.997, 63.973

From these spectra, the product was identified as bis (nonaflate butanesulfonyl) imide-N-butyl-N-octadecylpyrrolidinium.
The pKa in acetonitrile of the acid [bis (nonafluorobutanesulfonyl) imide] which is the source of the conjugate base in bis (nonafluorobutanesulfonyl) imide-N-butyl-N-octadecylpyrrolidinium is 0.0. Is.

(Example 5A)
<Synthesis of bis (nonaflate butane sulfonyl) imide-N-octadecylpyrrolidinium>
The synthesis of bis (nonaflatebutanesulfonyl) imide-N-octadecylpyrrolidinium was carried out according to the following scheme.

2.69 g of octadecylpyrrolidine synthesized in the same manner as in Example 4A was dissolved in ethanol, and 16.15 g of a 30% aqueous solution of bis (nonaflatebutanesulfonyl) imide was added. After completion of the addition, the mixture was stirred at room temperature for 1 hour and then heated under reflux for 1 hour. After removing the solvent, it was dissolved in dichloromethane and thoroughly washed with water, and then the solvent was removed. Recrystallization was performed from a mixed solvent of n-hexane and ethanol to obtain 6.82 g of colorless crystals of bis (nonafluorobutanesulfonyl) imide-N-octadecylpyrrolidinium. Yield 90.6%.

The FTIR absorption of the product and its attribution are shown below.
1076 cm ^-1 is the inverse symmetric expansion and contraction vibration of SNS, 1151 cm ^-1 , 1213 cm ^-1 , 1232 cm ^-1 is the symmetric expansion and contraction vibration of CF ₂ , 1354 cm ^-1 is the inverse symmetric expansion and contraction vibration of SO ₂ , and 1469 cm ^-1 is the change of CH ₂ . angular oscillation, symmetric stretching vibration of CH ₂ in 2852Cm ^-1, antisymmetric stretching vibration of CH ₂ in 2920 cm ^-1, it was observed NH stretching vibration 3182cm ^-1.

The peaks of proton ( ¹ H) NMR and carbon ( ¹³ C) NMR in heavy DMSO are shown below.
^{1 1} H-NMR (δppm); 0.855 (t, 3H, J = 6.6Hz), 1.140-1.330 (m, 30H), 1.650-1.780 (m, 2H), 2 .050-2.200 (m, 4H), 2.810-2.960 (m, 2H), 3.000-3.110 (m, 2H), 3.710-3.810 (m, 2H) , 7.750 (brs, 1H)
¹³ C-NMR (δppm); 14.070, 22.663, 22.770, 25.731, 26.357, 28.9211, 29.242, 29.349, 29.425, 29.532, 29. 684, 31.913, 54.914, 56.532

From these spectra, the product was identified as bis (nonaflate butanesulfonyl) imide-N-octadecylpyrrolidinium.
The pKa of the acid [bis (nonafluorobutanesulfonyl) imide] which is the source of the conjugate base in bis (nonaflatebutanesulfonyl) imide-N-octadecylpyrrolidinium in acetonitrile is 0.0.

(Example 6A)
<Synthesis of nonaflate butane sulfonic acid-N-octadecylpyrrolidinium>
The synthesis of nonaflate butane sulfonic acid-N-octadecylpyrrolidinium was carried out according to the following scheme.

2.91 g of octadecylpyrrolidine synthesized in the same manner as in Example 4A was dissolved in ethanol, and 2.70 g of nonaflate butane sulfonic acid was added. After completion of the addition, the mixture was stirred at room temperature for 1 hour and then heated under reflux for 1 hour. After removing the solvent, it was dissolved in dichloromethane and thoroughly washed with water, and then the solvent was removed. Recrystallization was performed from a mixed solvent of n-hexane and ethanol to obtain 6.82 g of nonaflate butane sulfonic acid-N-octadecylpyrrolidinium 5.12 g of colorless crystals. Yield 91.3%.

The FTIR absorption of the product and its attribution are shown below.
1134 cm ^-1 is SO ₂ symmetrical expansion and contraction vibration, 1232 cm ^-1 is CF ₂ symmetrical expansion and contraction vibration, 1352 cm ^-1 is SO ₂ inverse symmetrical expansion and contraction vibration, 1468 cm ^-1 is CH ₂ eccentric vibration, 2850 cm ^-1 is CH. ₂ symmetric stretching vibration, antisymmetric stretching vibration of CH ₂ in 2918Cm ^-1, the NH stretching vibration 3076cm ^-1 were observed.

The peaks of proton ( ¹ H) NMR and carbon ( ¹³ C) NMR in heavy DMSO are shown below.
^{1 1} H-NMR (δppm); 0.842 (t, 3H, J = 6.6Hz), 1.170-1.360 (m, 30H), 1.520-1.630 (m, 2H), 1 .760-1.910 (m, 2H), 1.910-2.040 (m, 2H), 2.870-3.020 (m, 2H), 3.000-3.120 (m, 2H) , 3.410-3.570 (m, 2H), 9.234 (brs, 1H)
¹³ C-NMR (δppm); 14.089, 22.254, 22.697, 25.399, 26.085, 28.650, 28.879, 28.985, 29.107, 29.214, 31. 473, 53.406, 54.154

From these spectra, the product was identified as nonaflate butane sulfonic acid-N-octadecylpyrrolidinium.
The pKa of the acid (nonafluorobutane sulfonic acid) that is the source of the conjugate base in nonafolic butane sulfonic acid-N-octadecylpyrrolidinium in acetonitrile is 0.7.

(Example 7A)
<Synthesis of -8-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenium trifluoromethanesulfonic acid>
The synthesis of -8-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenium trifluoromethanesulfonic acid was carried out according to the following scheme.

3.29 g of 8-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenium bromide synthesized in Example 2A was dissolved by heating water to dissolve 1.36 g of potassium trifluoromethanesulfonate. Aqueous solution was added. After stirring at room temperature for 1 hour, heating and reflux were performed for 1 hour. After cooling, the reaction solution was extracted with dichloromethane and washed thoroughly with water until the silver nitrate test was negative. The organic layer was dried over anhydrous sodium sulfate and the solvent was removed to obtain 3.74 g of a colorless liquid trifluoromethanesulfonic acid -8-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenenium. Yield 99.5%. This was recrystallized from a mixed solvent of n-hexane and dichloromethane.

The FTIR absorption of the product and its attribution are shown below.
1030 cm ^-1 with SO ₂ bond symmetric stretch vibration, 1146 cm ^-1 with SO ₂ bond inverse symmetric stretch vibration, 1261 cm ^-1 with CF ₃ symmetric stretch vibration, 1448 cm ^-1 with CH ₂ variable angle vibration, 1624 cm ^-1 symmetric stretching vibration of C = N, symmetric stretching vibration of CH ₂ in 2848cm ^-1, the antisymmetric stretching vibration of CH ₂ in 2916Cm ^-1 was seen.

The peaks of proton ( ¹ H) NMR and carbon ( ¹³ C) NMR of the obtained compound in CDCl ₃ are shown below.
^{1 1} H-NMR (CDCl ₃ , δppm); 0.843 (t, J = 6.6Hz, 3H), 1.160-1.320 (m, 30H), 1.520-1.640 (m, 2H) ), 1.670-1.820 (m, 6H), 2.095 (quint, J = 6.0Hz, 2H), 2.790-2.850 (m, 2H), 3.416-3.470 (M, 2H), 3.490-3.600 (m, 4H), 3.610-3.680 (m, 2H)
¹³ C-NMR (CDCl ₃ , δppm); 14.065, 20.048, 22.627, 23.070, 25.955, 26.474, 28.427, 28.519, 28.580, 29.114 , 29.297, 29.389, 29.450, 29.542, 29.603, 29.648, 31.862, 47.048, 49.094, 54.146, 55.290, 166.513

From these spectra, the product was identified as trifluoromethanesulfonic acid -8-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenium.
The pKa of the acid (trifluoromethanesulfonic acid) that is the source of the conjugate base in trifluoromethanesulfonic acid-8-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenium in acetonitrile is 0. It is 0.7.

(Example 8A)
<Synthesis of bis (nonaflate butane sulfonyl) imide-1-1'H, 1'H, 2'H, 2'H heptadecafluorodecyl-3-octadecil imidazolium>
The synthesis of bis (nonaflatebutanesulfonyl) imide-1-1'H, 1'H, 2'H, 2'H heptadecafluorodecyl-3-octadecil imidazolium was carried out according to the following scheme.

1-Octadecyl imidazole was obtained by dissolving 3 g of imidazole in 100 mL of acetonitrile, adding 14.9 g of octadecyl bromide and 2.51 g of potassium hydroxide, heating with stirring, and refluxing for 4 hours. After removing the solvent, it was extracted with dichloromethane and purified by column chromatography. Analysis by gas chromatography revealed a purity of 98.5% or higher.

3.95 g of 1-octadecylimidazole and 7.29 g of 1'H, 1'H, 2'H, 2'H heptadecafluorodecyl iodide were reacted at 90 ° C. for 65 hours. Ethyl acetate was added thereto, and the precipitated crystals were filtered and dried to obtain 9.67 g of pale yellow crystals. This was recrystallized from ethyl acetate to obtain 8.67 g of colorless crystals.

The peaks of proton ( ¹ H) NMR and carbon ( ¹³ C) NMR in deuterated chloroform are shown below.
^{1 1} H-NMR (CDCl ₃ , δppm); 0.841 (t, 3H, J = 6.6Hz), 1.125-1.350 (m, 30H), 1.865-1.970 (m, 2H) ), 2.854-3.019 (m, 2H), 4.242-4.312 (2H, m), 4.855-4.898 (m, 2H), 7.325-7.337 (m). , 1H), 7.608-7.620 (m, 1H), 10.196 (s, 1H)
¹³ C-NMR (CDCl ₃ , δppm); 14.040, 22.633, 26.174, 28.891, 29.303, 29.440, 29.547, 29.608, 29.639, 29.959 , 30.310, 31.608, 31.867, 42.689, 49.954, 50.641, 121.858, 122.942, 137.213

From these spectra, it was identified that the product was 1-1'H, 1'H, 2'H, 2'H heptadecafluorodecyl-3-octadecil imidazolium iodide.

Next, 3.29 g of 1-1'H, 1'H, 2'H, 2'H heptadecafluorodecyl-3-octadecylimidazolium iodide was dissolved in water, and potassium bis (nonafluorobutanesulfonyl) imide was dissolved. A solution prepared by dissolving 2.51 g in a mixed solvent of water and ethanol was added. The mixture was heated under reflux for 2 hours, cooled, the solvent was removed, and extraction was performed with dichloromethane. The organic layer was washed with pure water until the AgNO ₃ test became negative. After drying over anhydrous sodium sulfate, the solvent was removed to obtain 3.69 g of colorless crystals. Recrystallization was performed from a mixed solvent of n-hexane and ethanol to obtain 3.15 g of colorless crystals. Yield 64%.

The FTIR absorption of the product and its attribution are shown below.
Symmetric stretching vibration of SO ₂ bind to 1074cm ^-1, symmetric stretching vibration of CF ₂ to 1149cm ^-1 and 1198cm ^-1, antisymmetric stretching vibration of SO ₂ bind to 1352cm ^-1, bending of CH ₂ in 1469Cm ^-1 vibration, symmetric stretching vibration of the 1564 cm ^-1 C = N, symmetric stretching vibration of CH ₂ in 2850 cm ^-1, antisymmetric stretching vibration of CH ₂ in 2920 cm ^-1, the 3099Cm ^-1 and 3158cm ^-1 of CH of the imidazole ring Expansion and contraction vibration was seen.

The peaks of proton ( ¹ H) NMR and carbon ( ¹³ C) NMR in deuterated chloroform are shown below.
^{1 1} H-NMR (CDCl ₃ , δppm); 0.854 (t, 3H, J = 6.6Hz), 1.150-1.350 (m, 30H), 1.760-1.900 (m, 2H) ), 2.644-2.805 (m, 2H), 4.136-4.185 (m, 2H), 4.562-4.606 (m, 2H), 7.252-7.263 (m). , 1H), 7.454-7.465 (m, 1H), 8.946 (s, 1H)
¹³ C-NMR (CDCl ₃ , δppm); 14.024, 22.648, 26.006, 28.830, 29.247, 29.333, 29.440, 29.547, 29.669, 30.020 , 31.913, 42.300, 50.457, 122.209, 123.003, 136.312

From these spectra, the product was identified as bis (nonaflatebutanesulfonyl) imide-1-1'H, 1'H, 2'H, 2'H heptadecafluorodecyl-3-octadecil imidazolium. It was.
Bis (nonafluorobutanesulfonyl) imide-1-1'H, 1'H, 2'H, 2'H heptadecafluorodecyl-3-octadecil The acid that is the source of the conjugate group in imidazolium [bis (nona) Fluorobutanesulfonyl) imide] has a pKa of 0.0 in acetonitrile.

(Example 9A)
<Synthesis of bis (nonaflate butane sulfonyl) imide-1-1'H, 1'H, 2'H, 2'H heptadecafluorodecyl-3-methylimidazolium>
The synthesis of bis (nonaflatebutanesulfonyl) imide-1-1'H, 1'H, 2'H, 2'H heptadecafluorodecyl-3-methylimidazolium was carried out according to the following scheme.

Add 1.88 g of methylimidazole and 12.41 g of 1-1'H, 1'H, 2'H, 2'H heptadecafluorodecyl iodide to a flask and stir with a magnetic stirrer at 80 ° C. for 2 hours in a closed state. I made it react. After cooling, the mixture was washed with ethyl acetate and the solid matter was filtered. This was recrystallized from a mixed solvent of ethyl acetate and ethanol to obtain 6.23 g of colorless crystals. Yield 44%.

The peaks of proton ( ¹ H) NMR and carbon ( ¹³ C) NMR in deuterated chloroform are shown below.
^{1 1} H-NMR (CDCl ₃ , δppm); 2.976 (tt / J = 7.2Hz, 18.6Hz, 2H), 3.955 (s, 3H), 4.643 (t / J = 7.2Hz) , 2H), 7.618-7.630 (m, 1H), 7.766-7.772 (m, 1H), 9.095 (s, 1H)
¹³ C-NMR (CDCl ₃ , δppm); 32.119 (t / J = 21Hz), 36.790, 43.032, 123.926, 125.315, 138.716

From these spectra, it was identified that the product was 1-1'H, 1'H, 2'H, 2'H heptadecafluorodecyl-3-methylimidazolium iodide.

1-1'H, 1'H, 2'H, 2'H Heptadecafluorodecyl-3-methylimidazolium iodide 2.06 g was dissolved in pure water, and bis (nonaflatebutanesulfonyl) imide potassium salt 2 .07 g dissolved in a mixed solvent of pure water and ethanol was added. After the reaction at room temperature for 1 hour, the mixture was heated under reflux for 1 hour. The precipitate was filtered and then thoroughly washed with water. After drying, recrystallization was performed from a mixed solvent of n-hexane and ethanol to obtain 2.41 g of colorless crystals. Yield 67%.

The FTIR absorption of the product and its attribution are shown below.
Symmetric stretching vibration of SO ₂ bind to 1072cm ^-1, symmetric stretching vibration of CF ₂ to 1147cm ^-1 and 1176cm ^-1, antisymmetric stretching vibration of SO ₂ bind to 1352cm ^-1, to 1577cm ^-1 of C = N symmetrical Expansion and contraction vibration, CH expansion and contraction vibration of the imidazole ring was observed in 3097 cm ^-1 and 3157 cm ^-1 .

The peaks of proton ( ¹ H) NMR and carbon ( ¹³ C) NMR in deuterated chloroform are shown below.
^{1 1} H-NMR (CDCl ₃ , δppm); 2.833-3.020 (m, 2H), 3.934 (s, 3H), 4.613 (t / J = 7.2Hz, 2H), 7. 597-7.604 (m, 1H), 7.736-7.742 (m, 1H), 9.095 (s, 1H)
¹³ C-NMR (CDCl ₃ , δppm); 32.073 (t / J = 21Hz), 36.576, 42.941, 123.865, 125.254, 138.020

From these spectra, the product was identified as a bis (nonaflatebutanesulfonyl) imide-1-1'H, 1'H, 2'H, 2'H heptadecafluorodecyl-3-methylimidazolium. It was.
In addition, bis (nonafluorobutanesulfonyl) imide-1-1'H, 1'H, 2'H, 2'H heptadecafluorodecyl-3-methylimidazolium acid [bis (nona) Fluorobutanesulfonyl) imide] has a pKa of 0.0 in acetonitrile.

(Example 10A)
<Synthesis of nonaflate butane sulfonic acid-1-1'H, 1'H, 2'H, 2'H heptadecafluorodecyl-3-methylimidazolium>
Nonaflate butane sulfonic acid-1-1'H, 1'H, 2'H, 2'H Heptadecafluorodecyl-3-methylimidazolium was synthesized according to the following scheme.

To dissolve 2.06 g of 1-1'H, 1'H, 2'H, 2'H heptadecafluorodecyl-3-methylimidazolium iodide synthesized in Example 9A in pure water, nonafluorobutanesulfonic acid A solution prepared by dissolving 1.10 g of potassium in pure water was added. After the reaction at room temperature for 1 hour, the mixture was heated under reflux for 1 hour. The precipitate was filtered and then thoroughly washed with water. After drying, recrystallization was performed from a mixed solvent of n-hexane and ethanol to obtain 2.20 g of colorless crystals. Yield 85%.

The FTIR absorption of the product and its attribution are shown below.
Symmetric stretching vibration of SO ₂ bind to 1047cm ^-1, symmetric stretching vibration of CF ₂ to 1147cm ^-1 and 1194cm ^-1, antisymmetric stretching vibration of SO ₂ bind to 1254cm ^-1, to 1572cm ^-1 of C = N symmetrical Expansion and contraction vibration, CH expansion and contraction vibration of the imidazole ring was observed at 3093 cm ^-1 and 3159 cm ^-1 .

The peaks of proton ( ¹ H) NMR and carbon ( ¹³ C) NMR in deuterated chloroform are shown below.
^{1 1} H-NMR (CDCl ₃ , δppm); 2.886-3.020 (m, 2H), 3.938 (s, 3H), 4.619 (t / J = 7.2Hz, 2H), 7. 603-7.609 (m, 1H), 7.740-7.747 (m, 1H), 9.098 (s, 1H)
¹³ C-NMR (CDCl ₃ , δppm); 32.027 (t / J = 21Hz), 36.576, 42.941, 123.850, 125.239, 138.060

From these spectra, the product was identified as nonaflate butane sulfonic acid-1-1'H, 1'H, 2'H, 2'H heptadecafluorodecyl-3-methylimidazolium.
Nonaflate butane sulfonic acid-1-1'H, 1'H, 2'H, 2'H Heptadecafluorodecyl-3-methylimidazolium acid (nonafluorobutane sulfonic acid) that is the source of the conjugate base. The pKa in acetonitrile is 0.7.

(Example 11A)
<Synthesis of 1,3-bis [bis (nonaflatebutanesulfonyl) imide-N-octadecylimidazolium] propane>
The synthesis of 1,3-bis [bis (nonaflatebutanesulfonyl) imide-N-octadecylimidazolium)] propane was carried out according to the following scheme.

11.51 g of 1-octadecylimidazole and 1,3-dibromopropane were reacted at 80 ° C. for 1 h with stirring, and then the reaction temperature was raised to 100 ° C. for another 3 hours. Ethyl acetate was added to the reaction product and the precipitated precipitate was filtered. After vacuum drying, recrystallization was performed from a mixed solvent of n-hexane and ethanol to obtain 13.37 g of colorless crystals. Yield 89%.

The peaks of proton ( ¹ H) NMR and carbon ( ¹³ C) NMR in deuterated chloroform are shown below.
^{1 1} H-NMR (CDCl ₃ , δppm); 0.820 (t / J = 6.6Hz, 6H) 1.100-1.350 (m, 60H) 1.800-1.920 (m, 4H), 2.852 (quint / J = 7.2Hz, 2H), 4.191 (t / J = 7.2Hz, 4H), 4.692 (t / J = 7.2Hz, 4H), 7.201-7 .213 (m, 2H), 8.209-8.221 (m, 2H), 10.181 (s, 2H)
¹³ C-NMR (CDCl ₃ , δppm); 14.022, 22.584, 26.217, 28.857, 29.254, 29.407, 29.498, 29.560, 29.605, 30.033 , 30.811, 31.811, 46.700, 50.241, 121.291, 123.901, 136.447

From these spectra, the product was identified as 1,3-bis [1-octadecylimidazolium bromide] propane.

1.49 g of 1,3-bis [1-octadecylimidazolium bromide] propane is dissolved in pure water, an aqueous solution of 3.70 g of bis (nonafluorobutanesulfonyl) imidelithium is added, and after 1 h reaction at room temperature, 1 h heating reflux I let you. After cooling, it was extracted with dichloromethane and washed with pure water until the AgNO ₃ test became negative. After removing the solvent, recrystallization was performed from a mixed solvent of n-hexane and ethanol to obtain 4.80 g of colorless crystals. Yield 85%.

The FTIR absorption of the product and its attribution are shown below.
Antisymmetric vibration of SNS coupled to 1072cm ^-1, symmetric stretching vibration of CF ₂ to 1167cm ^-1, antisymmetric stretching vibration of SO ₂ bind to 1352cm ^-1, bending vibration of CH ₂ in 1468cm ^-1, to 1566cm ^-1 symmetric stretching vibration of C = N, symmetric stretching vibration of CH ₂ in 2850 cm ^-1, antisymmetric stretching vibration of CH ₂ in 2920 cm ^-1, CH] stretching vibration of the imidazole ring was observed in 3120Cm ^-1 and 3155cm ^-1 ..

The peaks of proton ( ¹ H) NMR and carbon ( ¹³ C) NMR in deuterated chloroform are shown below.
^{1 1} H-NMR (CDCl ₃ , δppm); 0.854 (t / J = 6.9Hz, 6H), 1.150-1.350 (m, 60H), 1.780-1.900 (m, 4H) ), 2.481-2.587 (m, 2H), 4.098 (t / J = 6.9Hz, 4H), 4.359 (t / J = 7.2Hz, 4H), 7.189-7 .200 (m, 2H), 7.600-7.610 (m, 2H), 8.333 (s, 2H)
¹³ C-NMR (CDCl ₃ , δppm); 14.085, 22.679, 26.143, 28.799, 29.257, 29.349, 29.455, 29.547, 29.654, 29.684 , 29.883, 31.470, 31.913, 46.413, 50.412, 122.057, 123.308, 135.458

From these spectra, the product was identified as 1,3-bis [bis (nonaflatebutanesulfonyl) imide-N-octadecylimidazolium)] propane.
The pKa in acetonitrile of the acid [bis (nonafluorobutanesulfonyl) imide] which is the source of the conjugate base in 1,3-bis [bis (nonafluorobutanesulfonyl) imide-N-octadecylimidazolium)] propane is , 0.0.

(Comparative Example 1A)
<Synthesis of hexafluorocyclopropane-1,3-bis (sulfonyl) imide-6-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenium>
For comparison, the acid of Example 1A was changed from bis (nonafluorobutanesulfonyl) imide to hexafluorocyclopropane-1,3-bis (sulfonyl) imide, hexafluorocyclopropane-1,3-bis (sulfonyl). The synthesis of imide-6-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenium was carried out according to the following scheme.

Hexafluorocyclopropane-1,3-bis (sulfonyl) imide 3.00 g in an ethanol solution of 6-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecene (2.18 g) synthesized in Example 1A. Was added, and the mixture was stirred at room temperature for 1 hour and then heated under reflux for 1 hour. After removing the solvent, it was dissolved in dichloromethane and washed thoroughly with water. The organic layer was dried over anhydrous sodium sulfate, and the solvent was removed. Vacuum dried at 90 ° C. for 3 days to add 4 colorless liquid hexafluorocyclopropane-1,3-bis (sulfonyl) imide-6-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecene. I got .86g. Yield 93.8%

The FTIR absorption of the product and its attribution are shown below.
1042 cm ^-1 is SNS inverse symmetric expansion and contraction vibration, 1091 cm ^-1 is SO ₂ symmetric expansion and contraction vibration, 1164 cm ^-1 is CF ₂ symmetric expansion and contraction vibration, 1360 cm ^-1 is SO ₂ coupling inverse symmetric expansion and contraction vibration, 1633 cm ^-1 is stretching vibration of C = N, symmetric stretching vibration of CH ₂ in 2848cm ^-1, antisymmetric stretching vibration of CH ₂ in 2920 cm ^-1, is NH stretching vibration 3387cm ^-1 were observed.

The peaks of proton ( ¹ H) NMR and carbon ( ¹³ C) NMR in deuterated chloroform are shown below.
^{1 1} H-NMR (CDCl ₃ , δppm); 0.869 (t, 3H, J = 6.6Hz), 1.170-1.340 (m, 32H), 1.441-1.555 (m, 2H) ), 1.600-1.750 (m, 4H), 1.772-1.832 (m, 2H), 1.941-2.101 (m, 2H), 2.670-2.780 (m) , 1H), 3.413 (t, 2H, J = 6.6Hz), 3.508 (t, 2H, J = 6.6Hz), 3.550-3.652 (m, 2H)
¹³ C-NMR (CDCl ₃ , δppm); 14.055, 19.260, 22.633, 26.052, 27.090, 28.542, 29.120, 29.226, 29.318, 29.364 , 29.486, 29.578, 29.608, 29.669, 31.867, 38.690, 43.177, 49.511, 53.861, 167.922

From these spectra, it was identified that the product was hexafluorocyclopropane-1,3-bis (sulfonyl) imide-6-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenium. ..
Hexafluorocyclopropane-1,3-bis (sulfonyl) imide-6-octadecyl-1,8-diazabicyclo [5.4.0] -7-Undeceneium is the acid that is the source of the conjugate base [hexafluorocyclopropane The pKa of -1,3-bis (sulfonyl) imide] in acetonitrile is -0.8.

(Comparative Example 2A)
<Synthesis of heptadecafluorooctanesulfonic acid-6-octadecil-1,8-diazabicyclo [5.4.0] -7-undecenium>
For comparison, the acid of Example 1A was changed from bis (nonafluorobutanesulfonyl) imide to heptadecafluorooctanesulfonic acid, heptadecafluorooctanesulfonic acid-6-octadecil-1,8-diazabicyclo [5.4]. .0] -7-Undecenium was synthesized according to the following scheme.

To an ethanol solution of 6-octadecil-1,8-diazabicyclo [5.4.0] -7-undecene (4.04 g) synthesized in Example 1A, 5.00 g of heptadecafluorooctanesulfonic acid was added, and the mixture was stirred at room temperature for 1 hour. After that, heating and reflux was performed for 1 hour. After removing the solvent, it was dissolved in dichloromethane and washed thoroughly with water. The organic layer was dried over anhydrous sodium sulfate, and the solvent was removed. Recrystallization was performed from a mixed solvent of n-hexane and ethanol to obtain 7.86 g of -6-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenenium heptadecafluorooctanesulfonic acid. Yield 86.9%

The FTIR absorption of the product and its attribution are shown below.
1055 cm ^-1 is SO ₂ symmetrical expansion and contraction vibration, 1252 cm ^-1 is CF ₂ symmetrical expansion and contraction vibration, 1368 cm ^-1 is SO ₂ coupling inverse symmetrical expansion and contraction vibration, 1467 cm ^-1 is CH ₂ variable angle vibration, 1643 cm ^-1 is stretching vibration of C = N, symmetric stretching vibration of CH ₂ in 2851cm ^-1, antisymmetric stretching vibration of CH ₂ in 2920 cm ^-1, is NH stretching vibration 3296cm ^-1 were observed.

The peaks of proton ( ¹ H) NMR and carbon ( ¹³ C) NMR in deuterated chloroform are shown below.
^{1 1} H-NMR (CDCl ₃ , δppm); 0.843 (t, 3H, J = 6.6Hz), 1.205-1.287 (m, 32H), 1.544-1.800 (m, 8H) ), 1.975-2.033 (m, 2H), 2.792-2.816 (m, 1H), 3.440-3.559 (m, 6H), 8.713 (brs, 1H)
¹³ C-NMR (CDCl ₃ , δppm); 14.024, 19.336, 22.633, 25.121, 26.311, 27.181, 28.311, 29.028, 29.303, 29.425 , 29.532, 29.608, 29.654, 31.882, 38.491, 43.375, 49.725, 53.785, 168.029

From these spectra, it was identified that the product was heptadecafluorooctanesulfonic acid-6-octadecil-1,8-diazabicyclo [5.4.0] -7-undecenium.
In addition, the acid [heptadecafluorooctanesulfonic acid] which is the source of the conjugate base in heptadecafluorooctanesulfonic acid-6-octadecil-1,8-diazabicyclo [5.4.0] -7-undecenium in acetonitrile pKa is 0.7.

(Comparative Example 3A)
<Synthesis of tris (trifluoromethanesulfonyl) methide-6-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenium>
For comparison, the acid of Example 1A was changed from bis (nonaflatebutanesulfonyl) imide to tris (trifluoromethanesulfonyl) methide, tris (trifluoromethanesulfonyl) methide-6-octadecyl-1,8-diazabicyclo [5]. .4.0] -7-Undecenium was synthesized according to the following scheme.

6.0 g of 6-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecene synthesized in the same manner as in Example 1A was dissolved in ethanol to make 65% concentrated nitric acid (d = 1.400) 0. Nitrate was synthesized by adding 96 g of ethanol diluent. The end point was checked with litmus paper where it became neutral. An ethanol solution of 4.45 g of tris (trifluoromethanesulfonyl) methide potassium salt was added, stirred for 30 minutes, and then heated to reflux for 30 minutes. After removing the solvent, the mixture is extracted with diethyl ether, the organic layer is thoroughly washed with water, dried over anhydrous sodium sulfate, and after removing the solvent, 7.60 g of tris (trifluoromethanesulfonyl) methide-6-octadecyl-1,8-diazabicyclo [5.4.0] -7-Undecenium was obtained. Yield 94.0%. Recrystallization was performed from a mixed solvent of n-hexane and ethanol.

The FTIR absorption of the product and its attribution are shown below.
1117 cm ^-1 is SO ₂ symmetric stretching vibration, 1198 cm ^-1 is CF ₃ symmetric stretching vibration, 1381 cm ^-1 is SO ₂ coupling inverse symmetric stretching vibration, 1470 cm ^-1 is CH ₂ eccentric vibration, 1632 cm ^-1 is stretching vibration of C = N, symmetric stretching vibration of CH ₂ in 2850 cm ^-1, antisymmetric stretching vibration of CH ₂ in 2918cm ^-1, the NH stretching vibration 3408cm ^-1 were observed.

The peaks of proton ( ¹ H) NMR and carbon ( ¹³ C) NMR in CDCl ₃ are shown below.
^{1 1} H-NMR (CDCl ₃ , δppm); 0.850 (t, 3H, J = 6.6Hz), 1.174-1.335 (m, 32H), 1.485-1.557 (m, 2H) ), 1.590-1.740 (m, 4H), 1.774-1.842 (m, 2H), 1.994-2.857 (m, 2H), 2.640-2.740 (m) , 1H), 3.360-3.430 (m, 2H), 3.450-3.690 (m, 4H), 7.160 (brs, 1H)
¹³ C-NMR (CDCl ₃ , δppm); 14.070, 19.122, 22.648, 25.899, 27.044, 28.463, 29.013, 29.165, 29.333, 29.455 , 29.578, 29.669, 31.882, 38.644, 43.238, 49.481, 53.968, 120.126 (q, J = 325Hz), 168.197

From these spectra, the product was identified as tris (trifluoromethanesulfonyl) methide-6-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenium.
In acetonitrile of the acid [tris (trifluoromethanesulfonyl) methide] which is the source of the conjugate base in tris (trifluoromethanesulfonyl) methide-6-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenium. The pKa in is -3.7.

(Comparative Example 4A)
<Synthesis of Hexafluorocyclopropane-1,3-bis (sulfonyl) imide-7-octadecyl-1,5,7-triazabicyclo [4.4.0] -5-decenium>
It has a 7-octadecyl-1,5,7-triazabicyclo [44.0] -5-decene structure in the cation part, and hexafluorocyclopropane-1,3-bis (sulfonyl) imide in the anion part. The synthesis of hexafluorocyclopropane-1,3-bis (sulfonyl) imide-7-octadecyl-1,5,7-triazabicyclo [4.4.0] -5-decenium having is carried out according to the following scheme. went.

First, the synthesis of the raw material 7-n-octadecyl-1,5,7-triazabicyclo [4.4.0] -5-decene (octadecene TBD) will be described.
R. W. Method of Alder et al. [Non-patent literature, Roger W. et al. Alder, Rodney W. Mowlam, David J. et al. Vachon and Gray R. Weisman, "New Synthetic Routing to Macrocyclic Triamines," J. et al. Chem. Sos. Chem. Common. pp. See 507-508 (1992)] for synthesis.
That is, sodium hydride (55% by mass hexane) was dissolved in dry THF at 10 ° C. in 8.72 g of 1,5,7-triazabicyclo [4.4.0] -5-decene (TBD). In addition, it was stirred. Octadecane brominated was added dropwise over 20 minutes while maintaining the temperature at 10 ° C. Then, the mixture was stirred at 10 ° C. for 30 minutes, then stirred at room temperature for 2 hours, and then heated to reflux for 1 hour. The temperature was returned to room temperature, and excess sodium hydride was added for the reaction. After removing the solvent, column chromatography was performed on amino-treated silica gel to obtain a pale yellow object.

Hexafluorocyclopropane-1,3-bis was obtained by dissolving 4.00 g of 7-octadecyl-1,5,7-triazabicyclo [4.4.0] -5-decene, which is the desired product, in ethanol. An ethanol solution of 3.00 g of (sulfonyl) imide was added. After stirring for 30 minutes and refluxing by heating for 30 minutes, the solvent is removed, dissolved in dichloromethane, thoroughly washed with water, dried over anhydrous sodium sulfate, and the solvent is removed to remove the colorless hexafluorocyclopropane-1. , 3-Bis (sulfonyl) imide-7-octadecyl-1,5,7-triazabicyclo [4.4.0] -5-decenium 4.60 g was obtained. Yield 92.0%. Recrystallization was performed from a mixed solvent of n-hexane and ethanol.

The FTIR absorption of the product and its attribution are shown below.
1042 cm ^-1 is SNS reverse symmetric stretch vibration, 1092 cm ^-1 is SO ₂ symmetric stretch vibration, 1157 cm ^-1 is CF ₂ symmetric stretch vibration, 1361 cm ^-1 is SO ₂ bond reverse symmetric stretch vibration, 1628 cm ^-1 is stretching vibration of C = N, symmetric stretching vibration of CH ₂ in 2849cm ^-1, antisymmetric stretching vibration of CH ₂ in 2921cm ^-1, the NH stretching vibration 3412cm ^-1 were observed.

The peaks of proton ( ¹ H) NMR and carbon ( ¹³ C) NMR in CDCl ₃ are shown below.
^{1 1} H-NMR (CDCl ₃ , δppm); 0.847 (t, 3H, J = 6.6Hz), 1.222-1.274 (m, 30H), 1.460-1.600 (m, 2H) ), 1.969-2.855 (m, 4H), 3.210 (t, 2H, J = 10Hz), 3.310-3.409 (m, 8H), 5.931 (brs, 1H)
¹³ C-NMR (CDCl ₃ , δppm); 14.055, 20.450, 20.740, 22.633, 26.494, 27.044, 29.226, 29.303, 29.425, 29.532 , 29.608, 29.654, 31.867, 38.980, 46.428, 47.298, 47.786, 50.183, 150.385

From these spectra, the product is hexafluorocyclopropane-1,3-bis (sulfonyl) imide-7-octadecyl-1,5,7-triazabicyclo [4.4.0] -5-decenium. Was identified.
The acid that is the source of the conjugate base in hexafluorocyclopropane-1,3-bis (sulfonyl) imide-7-octadecyl-1,5,7-triazabicyclo [4.4.0] -5-decenium [ Hexafluorocyclopropane-1,3-bis (sulfonyl) imide] has a pKa of -0.8 in acetonitrile.

(Comparative Example 5A)
<Synthesis of heptadecafluorooctanesulfonic acid-7-octadecyl-1,5,7-triazabicyclo [4.4.0] -5-decenium>
Heptadecafluorooctanesulfonic acid having a 7-octadecyl-1,5,7-triazabicyclo [4.4.0] -5-decene structure in the cation part and a heptadecafluorooctanesulfonic acid in the anion part. The synthesis of -7-octadecyl-1,5,7-triazabicyclo [4.4.0] -5-decenium was carried out according to the following scheme.

3.91 g of 7-octadecyl-1,5,7-triazabicyclo [4.4.0] -5-decene synthesized in Comparative Example 4A was dissolved in ethanol, and 5.00 g of heptadecafluorooctanesulfonic acid was dissolved in ethanol. The solution was added. After stirring for 30 minutes and heating under reflux for 30 minutes, the solvent is removed, dissolved in dichloromethane and a small amount of ethanol, thoroughly washed with water, dried over anhydrous sodium sulfate, and the solvent is removed to remove the colorless heptadeca. -7-Octadecyl-1,5,7-triazabicyclo [4.4.0] -5-decenium 8.50 g of fluorooctanesulfonic acid was obtained. Yield 95.4%. Recrystallization was performed from a mixed solvent of n-hexane and ethanol.

The FTIR absorption of the product and its attribution are shown below.
1151cm ^-1 -1287cm ^-1 to symmetric stretching vibration of CF, antisymmetric stretching vibration of SO ₂ bind to 1373cm ^-1, stretching vibration of C = N to 1602 cm ^-1, symmetric stretching vibration of CH ₂ in 2851cm ^-1, 2924cm ^-1 antisymmetric stretching vibration of CH _2, was observed NH stretching vibration 3289cm ^-1.

The peaks of proton ( ¹ H) NMR and carbon ( ¹³ C) NMR in CDCl ₃ are shown below.
^{1 1} H-NMR (CDCl ₃ , δppm); 0.841 (t, 3H, J = 6.6Hz), 1.205-1.239 (m, 30H), 1.460-1.590 (m, 2H) ), 1.915-2.060 (m, 4H), 3.254-3.316 (m, 8H), 3.390-3.450 (m, 2H), 7.158 (brs, 1H)
¹³ C-NMR (CDCl ₃ , δppm); 14.041, 20.609, 20.970, 22.649, 26.419, 27.091, 29.319, 29.350, 29.502, 29.670 , 31.883, 38.767, 46.368, 47.314, 47.986, 50.230, 150.417

From these spectra, it was identified that the product was heptadecafluorooctanesulfonic acid-7-octadecil-1,5,7-triazabicyclo [44.0] -5-decenium.
It should be noted that the acid [heptadecafluorooctanesulfonic acid] which is the source of the conjugate base in heptadecafluorooctanesulfonic acid-7-octadecyl-1,5,7-triazabicyclo [4.4.0] -5-decenium. The pKa in acetonitrile is 0.7.

(Comparative Example 6A)
<Synthesis of hexafluorocyclopropane-1,3-bis (sulfonyl) imide-N-octadecylpyrrolidinium>
Unlike Example 5A or Example 6A, it is an ionic liquid having an N-octadecylpyrrolidinium structure in the cation part, but the anion part is changed to hexafluorocyclopropane-1,3-bis (sulfonyl) imide. The synthesis of hexafluorocyclopropane-1,3-bis (sulfonyl) imide-N-octadecylpyrrolidinium was carried out according to the following scheme.

2.68 g of octadecylpyrrolidine synthesized in the same manner as in Example 4A was dissolved in ethanol, and 2.67 g of hexafluorocyclopropane-1,3-bis (sulfonyl) imide dissolved in ethanol was added. After completion of the addition, the mixture was stirred at room temperature for 1 hour and then heated under reflux for 1 hour. After removing the solvent, it was dissolved in dichloromethane, thoroughly washed with water, dried over anhydrous magnesium sulfate, and then the solvent was removed to obtain 4.96 g of a colorless solid. Yield 92.8%. Recrystallization was performed from a mixed solvent of n-hexane and ethanol to obtain 4.10 g of hexafluorocyclopropane-1,3-bis (sulfonyl) imide-N-octadecylpyrrolidinium.

The FTIR absorption of the product and its attribution are shown below.
Symmetric stretching vibration of CF ₂ to 1151cm ^-1, antisymmetric stretching vibration of SO ₂ to 1354cm ^-1, bending vibration of CH ₂ in 1466cm ^-1, symmetric stretching vibration of CH ₂ in 2850 cm ^-1, to 2918cm ^-1 CH Inverse symmetric expansion and contraction vibration of ₂ and NH expansion and contraction vibration were observed at 3192 cm ^-1 .

The peaks of proton ( ¹ H) NMR and carbon ( ¹³ C) NMR in heavy DMSO are shown below.
^{1 1} H-NMR (δppm); 0.843 (t, 3H, J = 6.6Hz), 1.150-1.360 (m, 30H), 1.50-1.630 (m, 2H), 1 .760-2.060 (m, 4H), 2.860-3.140 (m, 4H), 3.400-3.580 (m, 2H), 9.239 (brs, 1H)
¹³ C-NMR (δppm); 14.119, 22.270, 22.697, 25.399, 26.101, 28.650, 28.879, 28.985, 29.107, 29.214, 31. 473, 53.406, 54.154

From these spectra, the product was identified as hexafluorocyclopropane-1,3-bis (sulfonyl) imide-N-octadecylpyrrolidinium.
In acetonitrile of the acid [hexafluorocyclopropane-1,3-bis (sulfonyl) imide] which is the source of the conjugate base in hexafluorocyclopropane-1,3-bis (sulfonyl) imide-N-octadecylpyrrolidinium. The pKa at is -0.8.

(Comparative Example 7A)
<Synthesis of nonaflate butane sulfonic acid-1-1'H, 1'H, 2'H, 2'H heptadecafluorodecyl-3-octadecil imidazolium>
Nonaflate butane sulfonic acid-1-1'H, 1'H, 2'H, 2'H heptadecafluorodecyl-3-octadecil Imidazoleium was synthesized according to the following scheme.

Next, 3.87 g of 1-1'H, 1'H, 2'H, 2'H heptadecafluorodecyl-3-octadecil imidazolium iodide synthesized in Example 8A was dissolved in water, and nonafluorobutane sulfone was added. A solution of 1.76 g of potassium acid in water was added. After stirring at room temperature for 1 h, the mixture was heated under reflux for 1 hour, cooled, the solvent was removed, and extraction was performed with dichloromethane. The organic layer was washed with pure water until the AgNO ₃ test became negative. After drying over anhydrous sodium sulfate, the solvent was removed, and recrystallization was performed from a mixed solvent of n-hexane and ethanol to obtain 4.20 g of colorless crystals. Yield 91%.

The FTIR absorption of the product and its attribution are shown below.
Symmetric stretching vibration of SO ₂ bind to 1147cm ^-1, symmetric stretching vibration of CF ₂ to 1200 cm ^-1, bending vibration of CH ₂ in 1456cm ^-1, symmetric stretching vibration of C = N to 1564 cm ^-1, the 2850 cm ^-1 symmetric stretching vibration of CH _2, antisymmetric stretching vibration of CH ₂ in 2916cm ^-1, to 3113cm ^-1 and 3150 cm ^-1 stretching vibration of CH of the imidazole ring was observed.

The peaks of proton ( ¹ H) NMR and carbon ( ¹³ C) NMR in deuterated chloroform are shown below.
^{1 1} H-NMR (CDCl ₃ , δppm); 0.849 (t / J = 6.9Hz, 3H), 1.160-1.380 (m, 30H), 1.860-1.970 (m, 2H) ), 2.620-3.010 (m, 2H), 4.254 (t / J = 6.6Hz, 2H), 4.845 (t / J = 6.6Hz, 2H), 7.276 (s) , 1H), 7.526 (s, 1H), 10.184 (s, 1H)
¹³ C-NMR (CDCl ₃ , δppm); 14.070, 22.648, 26.189, 28.906, 29.318, 29.455, 29.5622, 29.623, 29.669, 29.990 , 31.882, 32.691, 32.722, 42.719, 50.671, 121.706, 122.881, 137.503

From these spectra, the product was identified as nonaflate butane sulfonic acid-1-1'H, 1'H, 2'H, 2'H heptadecafluorodecyl-3-octadecil imidazolium.
Nonaflate butane sulfonic acid-1-1'H, 1'H, 2'H, 2'H heptadecafluorodecyl-3-octadecyl The acid that is the source of the base in imidazolium (nonafluorobutane sulfonic acid). The pKa in acetonitrile is 0.7.

(Comparative Example 8A)
<Synthesis of bis (nonaflate butane sulfonyl) imide-1-butyl-3-n-octadecylimidazolium>
For comparison, the monocationic ionic liquid bis (nonafolic butanesulfonyl) imide-1-butyl-3-n-octadecylimidazolium was synthesized according to the following scheme.

10.7 g of 1-octadecylimidazole and 6.03 g of bromobutane were dissolved in acetonitrile, and the mixture was heated under reflux for 5 hours. After removing the solvent, recrystallization was performed from a mixed solvent of n-hexane and ethanol to obtain 1-butyl-3-octadecylimidazolium bromide. 1.27 g of this bromide was dissolved in ethanol, 1.81 g of an ethanol solution of bis (nonaflatebutanesulfonyl) imide potassium was added thereto, and the mixture was stirred to generate a colorless precipitate. The solution was heated to reflux for 1 hour, cooled to separate the precipitate and thoroughly washed with pure water. Recrystallization was performed from a mixed solvent of n-hexane and ethanol to obtain 2.06 g of colorless crystalline bis (nonafluorobutanesulfonyl) imide-1-butyl-3-n-octadecylimidazolium. Yield 75%.

The FTIR absorption of the product and its attribution are shown below.
Symmetric stretching vibration of SO ₂ to 1072cm ^-1, symmetric stretching vibration of CF ₂ to 1137cm ^-1 and 1168cm ^-1, antisymmetric stretching vibration of SO ₂ bind to 1352cm ^-1, bending vibration of CH ₂ in 1469cm ^-1, stretching vibration of the 1564cm ^-1 C = N, symmetric stretching vibration of CH ₂ in 2850 cm ^-1, antisymmetric stretching vibration of CH ₂ in 2920 cm ^-1, the stretching vibration of CH of the imidazole ring to 3097cm ^-1 and 3157cm ^-1 It was seen.

The peaks of proton ( ¹ H) NMR and carbon ( ¹³ C) NMR in deuterated chloroform and their attribution are shown below.
^{1 1} H-NMR (CDCl ₃ , δppm); 0.837 (t / J = 6.6Hz, 3H), 0.885 (t / J = 7.2Hz, 3H), 1.140-1.300 (m) , 32H), 1.760 (quint / J = 7.2Hz, 4H), 4.112-4.173 (m, 4H), 7.776 (s, 1H), 7.781 (s, 1H), 9.175 (s, 1H)
¹³ C-NMR (CDCl ₃ , δppm); 13.341, 14.043, 18.927, 22.239, 25.627, 28.466, 28.863, 28.970, 29.062, 29.184 , 29.413, 31.443, 48.751, 49.026, 122.624, 136.101

From these spectra, it was identified that the product was bis (nonaflatebutanesulfonyl) imide-1-butyl-3-n-octadecylimidazolium.
The pKa of the acid [bis (nonafluorobutanesulfonyl) imide], which is the source of the conjugate base in bis (nonafluorobutanesulfonyl) imide-1-butyl-3-n-octadecylimidazolium, in acetonitrile is 0.0. Is.

(Comparative Example 9A)
<Synthesis of 1,5-bis [bis (nonaflatebutanesulfonyl) imide-1-octadecylimidazolium] pentane>
The synthesis of 1,5-bis [bis (nonaflatebutanesulfonyl) imide-1-octadecylimidazolium] pentane was carried out according to the following scheme.

10.00 g of 1-octadecylimidazole synthesized in Example 8A and 3.58 g of 1,5-dibromoheptane were dissolved in isopropanol. The obtained liquid was added to a three-necked flask equipped with a three-one motor and a cooler, and was heated to reflux for 3 hours. After removing the solvent, recrystallization was performed from a mixed solvent of ethyl acetate and ethanol to obtain 12.82 g of colorless crystalline 1,5-bis (1-octadecylimidazolium bromide) pentane. Yield 94%.

1.93 g of 1,5-bis (1-octadecylimidazolium bromide) pentane was dissolved in water, 2.76 g of bis (nonaflatebutanesulfonyl) imide potassium salt dissolved in water and a small amount of ethanol was added, and at room temperature. After stirring for 2 hours, the mixture was heated and refluxed for 2 hours. After completion of the reaction, the mixture was filtered and washed thoroughly with water until the AgNO ₃ test of the filtrate became negative. Vacuum drying was carried out at 70 ° C. for 10 hours to obtain 4.00 g of a waxy compound of 1,5-bis [bis (nonaflatebutanesulfonyl) imide-1-octadecylimidazolium] pentane. Yield 96.5%.

The FTIR absorption of the product and its attribution are shown below.
1072 cm ^-1 is SO ₂ symmetrical expansion and contraction vibration, 1167 cm ^-1 is CF ₂ symmetrical expansion and contraction vibration, 1352 cm ^-1 is SO ₂ coupling inverse symmetrical expansion and contraction vibration, 1468 cm ^-1 is CH ₂ variable angle vibration, 1566 cm ^-1 is stretching vibration of C = N, symmetric stretching vibration of CH ₂ in 2854cm ^-1, antisymmetric stretching vibration of CH ₂ was observed in 2924 cm ^-1.

The peaks of proton ( ¹ H) NMR and carbon ( ¹³ C) NMR in heavy DMSO and their attribution are shown below.
^{1 1} H-NMR (deuterium DMSO, δppm); 0.828 (t, 6H, J = 6.9Hz), 1.130-1.340 (m, 62H), 1.710-1.880 (m, 8H) ), 4.106-4.169 (m, 8H), 7.750-7.761 (m, 2H), 7.772-7.782 (m, 2H), 9.141 (s, 2H)
¹³ C-NMR (heavy DMSO, δppm); 13.967, 22.239, 25.689, 28.543, 28.772, 28.879, 29.016, 29.138, 29.214, 29.520 , 31.458, 48.675, 49.041, 122.594, 122.639, 136.086

From these spectra, the product was identified as 1,5-bis [bis (nonaflatebutanesulfonyl) imide-1-octadecylimidazolium] pentane.
The pKa in acetonitrile of the acid [bis (nonafluorobutanesulfonyl) imide], which is the source of the conjugate base in 1,5-bis [1-octadecylimidazolium-bis (nonafluorobutanesulfonyl) imide] pentane, is It is 0.0.

(Comparative Example 10A)
<Synthesis of 1,9-bis [bis (nonafluorobutanesulfonyl) imide-1-octadecylimidazolium] nonane>
The synthesis of 1,9-bis [bis (nonafluorobutanesulfonyl) imide-1-octadecylimidazolium] nonane was carried out according to the following scheme.

10.91 g of 1-octadecylimidazole synthesized in Example 8A and 4.88 g of 1,9-dibromononane were dissolved in isopropanol. The obtained liquid was added to a three-necked flask equipped with a three-one motor and a cooler, and was heated to reflux for 3 hours. After removing the solvent, recrystallization was performed from a mixed solvent of n-hexane and ethanol to obtain 14.11 g of colorless crystals of 1,9-bis (1-octadecylimidazolium bromide) nonane. Yield 89%.

3.00 g of 1,9-bis (1-octadecylimidazolium bromide) nonane was dissolved in water, and an aqueous solution of 4.04 g of bis (nonafluorobutanesulfonyl) imide lithium salt was added. After stirring at room temperature for 1 hour, the mixture was heated under reflux for 2 hours. After completion of the reaction, the crystals were filtered. The filtrate was thoroughly washed with water until the AgNO ₃ test was negative to obtain 5.16 g of 1,9-bis [bis (nonafluorobutanesulfonyl) imide-1-octadecylimidazolium] nonane. Yield 73.7%.

The FTIR absorption of the product and its attribution are shown below.
1072 cm ^-1 is SNS inverse symmetric expansion and contraction vibration, 1169 cm ^-1 is CF ₂ symmetric expansion and contraction vibration, 1352 cm ^-1 is SO ₂ coupling inverse symmetric expansion and contraction vibration, 1469 cm ^-1 is CH ₂ variable angle vibration, 1564 cm ^-1 is C = symmetric stretching vibration of N, symmetric stretching vibration of CH ₂ in 2850 cm ^-1, antisymmetric stretching vibration of CH ₂ was observed in 2920 cm ^-1.

The peaks of proton ( ¹ H) NMR and carbon ( ¹³ C) NMR in CDCl ₃ are shown below.
^{1 1} H-NMR (CDCl ₃ , δppm); 0.870 (t / J = 6.9Hz, 6H), 1.180-1.370 (m, 70H), 1.780-1.920 (m, 8H) ), 4.151 (quin / J = 7.2Hz, 8H), 7.244-7.257 (m, 2H), 7.398-7.410 (m, 2H), 8.816 (s, 2H) )
¹³ C-NMR (CDCl ₃ , δppm); 14.055, 22.663, 25.334, 26.082, 27.807, 27.929, 28.845, 29.288, 29.333, 29.455 , 29.562, 29.669, 29.730, 30.127, 31.898, 50.015, 50.091, 121.980, 122.621, 135.366

From these spectra, the product was identified as 1,9-bis [bis (nonafluorobutanesulfonyl) imide-1-octadecylimidazolium] nonane.
The pKa in acetonitrile of the acid [bis (nonafluorobutanesulfonyl) imide] which is the source of the conjugate base in 1,9-bis [bis (nonafluorobutanesulfonyl) imide-1-octadecylimidazolium] nonane is It is 0.0.

The ionic liquids synthesized in the above Examples and Comparative Examples are summarized below.

(Example 1B to Example 11B, and Comparative Example 1B to Comparative Example 10B)
<Results of measurement of solubility in fluorine-based solvent>
Solubility test of the ionic liquids synthesized in each example and each comparative example using Bertrel XF [CF ₃ (CHF) ₂ CF ₂ CF ₃ ] manufactured by Mitsui-Dupont Fluorochemical Co., Ltd. as a fluorine-based solvent. Was done.
An ionic liquid was added to a predetermined mass of Bertrel XF, and after irradiating with ultrasonic waves for 5 minutes, the solution was left for 1 day, and its solubility was visually confirmed.
Specifically, 0.5 parts by mass and 0.1 parts by mass of ionic liquids were added to 100 parts by mass of Bertrel XF (25 ° C.), irradiated with ultrasonic waves for 5 minutes, and then left for 1 day. , The solubility was visually confirmed and evaluated according to the following evaluation criteria.
In addition, it was visually confirmed, and it was judged that the case where it was transparent was dissolved. In addition, when it was opaque or insoluble, it was judged to be insoluble (insoluble).
The results are shown in Tables 2-1 to 2-2.

〔Evaluation criteria〕
・ 0.5% by mass or more:
It is dissolved by adding 0.5 parts by mass.
-0.1% by mass or more and less than 0.5% by mass:
It is insoluble when 0.5 parts by mass is added, but is dissolved when 0.1 parts by mass is added.
・ Less than 0.1% by mass:
It is insoluble with the addition of either 0.5 parts by mass or 0.1 parts by mass.

The solubility of the ionic liquid of Example 1A in a fluorinated solvent was 0.5% by mass or more.
The solubility of the ionic liquid of Example 2A in a fluorine-based solvent was 0.5% by mass or more.
The solubility of the ionic liquid of Example 3A in a fluorine-based solvent was 0.5% by mass or more.
The solubility of the ionic liquid of Example 4A in a fluorinated solvent was 0.5% by mass or more.
The solubility of the ionic liquid of Example 5A in a fluorinated solvent was 0.5% by mass or more.
The solubility of the ionic liquid of Example 6A in a fluorinated solvent was 0.1% by mass or more and less than 0.5% by mass.
The solubility of the ionic liquid of Example 7A in a fluorinated solvent was 0.5% by mass or more.
The solubility of the ionic liquid of Example 8A in a fluorinated solvent was 0.1% by mass or more and less than 0.5% by mass.
The solubility of the ionic liquid of Example 9A in a fluorinated solvent was 0.5% by mass or more.
The solubility of the ionic liquid of Example 10A in a fluorinated solvent was 0.1% by mass or more and less than 0.5% by mass.
The solubility of the ionic liquid of Example 11A in a fluorinated solvent was 0.5% by mass or more.

The solubility of the ionic liquids of Comparative Examples 1A to 10A in a fluorine-based solvent was less than 0.1% by mass.

As can be seen from this, the ionic liquid used in the examples has a solubility of 0.1% by mass or more in the fluorine-based solvent Bartrel XF, and is sufficient for production as a hard disk application.

Further, even when the same 6-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecene skeleton is used, as in Example 1B, when the bis (nonaflatebutanesulfonyl) imide is used as an anion. Is higher than that of hexafluorocyclopropane-1,3-bis (sulfonyl) imide (Comparative Example 1B), heptadecafluorooctanesulfonic acid (Comparative Example 2B), and tris (trifluoromethanesulfonyl) methide (Comparative Example 3B). Has excellent solubility.

Further, even when the same 6-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecene skeleton is used, when trifluoromethanesulfonic acid is used as an anion as in Example 7B, hexafluoro It has better solubility than the cases of cyclopropane-1,3-bis (sulfonyl) imide (Comparative Example 1B) and heptadecafluorooctanesulfonic acid (Comparative Example 2B).

However, as shown in Table 3, the fluorine contents contained in the molecular weight of the anion portion are 0.589, 0.389, 0.649 and 0.372, respectively, and heptadecafluorooctanesulfonic acid having a high fluorine content. In the case of, the solubility is low. However, it is not possible to consider the solubility simply by the fluorine content. Among them, it can be seen that the bis (nonaflatebutanesulfonyl) imide-based ionic liquid has improved solubility in a fluorine-based solvent.

Further, when Example 8B and Comparative Example 7B were compared, the structure of the imidazole in the cation portion was the same, and the solubility was improved when the anion portion was changed from sulfonic acid to sulfonylimide. Comparing Example 8B and Comparative Example 8B, the solubility is improved because the molecular design is such that fluorinated carbon is introduced into the butyl group at the 1-position. As a whole, it can be seen that the bis (nonafolic butane sulfonyl) imide-based ionic liquid has improved solubility in the fluorine-based solvent with respect to the corresponding nonafluorobutane sulfonic acid.

Further, in Examples 9B and 10B, since the fluorine content of the whole molecule was increased by changing the octadecyl group of Example 8B to a methyl group, its solubility was improved so that it could be dissolved even with a sulfonate. became.

Example 11B, Comparative Example 9B and Comparative Example 10B are comparisons of dications, the lengths of which are binding groups are 3, 5 and 9, respectively. As a result, it was found that the solubility in a fluorine-based solvent can be improved when the length of the binding group is short.

From the examination results of the present inventors, the following findings were obtained regarding the solubility of ionic liquids in fluorine-based solvents.
It was found that even in an ionic liquid having the same octadecyl-1,8-diazabicyclo [5.4.0] -7-undecene structure, the solubility differs depending on the position where the octadecyl group is introduced. That is, in the case introduced at the 6-position, only the one having a bis (nonaflate sulfonyl) imide structure as an anion is dissolved, but in the case introduced at the 8-position, as can be seen from Examples 2B and 3B. Not only the bis (nonaflatebutanesulfonyl) imide structure but also the perfluorosulfonic acid structure that was not dissolved by the one introduced at the 6-position will be dissolved (Comparative Example 2B). That is, it can be seen that the solubility is improved by introducing an octadecyl group at the 8-position.

In the case of an ionic liquid having 7-octadecyl-1,5,7-triazabicyclo [4.4.0] -5-decene as a cation structure, hexafluorocyclopropane-1,3-bis of Comparative Example 4A It does not dissolve in (sulfonyl) imide or heptadecafluorooctanesulfonic acid of Comparative Example 5A. In Comparative Example 3A, tris (trifluoromethanesulfonyl) methide-6-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecene is not dissolved. Furthermore, based on the results of other studies not introduced here, the cationic structure of 7-octadecyl-1,5,7-triazabicyclo [4.4.0] -5-decene is 6 in terms of solubility. It is presumed that the solubility is higher than that of -octadecyl-1,8-diazabicyclo [5.4.0] -7-undecene.

It was found that the solubility of an ionic liquid having an octadecyl-1,8-diazabicyclo [5.4.0] -7-undecene structure differs depending on the anion structure. That is, it was found that hexafluorocyclopropane-1,3-bis (sulfonyl) imide and heptadecafluorooctanesulfonic acid as anions do not dissolve, but trifluoromethanesulfonic acid dissolves. In this case, the solubility cannot be explained by the fluorine content of the anion portion.

In the 1-heptadecafluorodecylimidazole skeleton, the structure having a methyl group at the 3-position is more soluble than the one having an octadecyl group, and even nonafluorobutane sulfonate also dissolves in Bertrel XF. In this case, it is considered that the solubility in the fluorine-based solvent was improved because the fluorine content of the whole molecule was increased by changing the long-chain hydrocarbon to a methyl group.

In the case of the dication, the result was further tricky, the solubility was less than 0.1% by weight when the number of binding chains was 9 and 5, and the solubility was improved only when the number was 3. In the case of an ionic liquid having a pyrrolidine skeleton N-butyl-N-octadecylpyrrolidine skeleton, the solubility in a fluorosolvent is 0.5% by mass or more, but in the case of a dication, 0.1% by mass. If it is less than, the solubility deteriorates. However, in the case of the imidazole skeleton, the monocation of butyl-octadecylimidazole has a solubility of less than 0.1% by mass in a fluorine-based solvent, but it has been found that the solubility is improved by using a dication.

Although not introduced here, most imidazole-based ionic liquids having a long-chain alkyl group do not dissolve in a fluorine solvent. However, some of the pyrrolidine-based ionic liquids are soluble in Examples 4A, 5A and 6A, and it has been found that the pyrrolidine-based ionic liquid is easily dissolved.

Therefore, the solubility of the cation moiety and the anion moiety in the fluorine-based solvent can be summarized as follows.
Here, among the general formula (A-1), the general formula (A-2), the general formula (B), the general formula (C) and the general formula (D), R ¹ and R ² are , As mentioned above.
In the general formula (A-1), R ²¹ represents a hydrocarbon group.
In the general formula (E), R ¹ , R ² , and R ³ independently represent either a hydrogen atom or a long-chain hydrocarbon group. However, at least one of R ¹ , R ² , and R ³ is a long-chain hydrocarbon group.
Here, in the general formula (X), l is as described above.
In the general formula (Y) and the general formula (Z), n is as described above.

Therefore, as a combination of an acid and a base in an ionic liquid, an alkyl group is introduced into nitrogen as a base, pyrrolidine [general formula (D)], octadecyldiazabicyclo [5.4.0] -7-undecene [general formula]. (B), general formula (A-1), general formula (A-2)], or 1,5,7-triazabicyclo [4.4.0] -5-decene [general formula (C)] skeleton Is better to use. Further, as the acid, it is preferable to use perfluoroalkanesulfonylimide [general formula (X)] or perfluorosulfonic acid having a short alkyl chain [general formula (Y)].
s

(Example 1C)
<Results of thermal stability measurement>
5%, 10% and 20% weight loss temperatures of bis (nonafluorobutanesulfonyl) imide-6-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecene are 352.9 ° C. and 378, respectively. The temperature is .2 ° C. and 396.7 ° C., which is 100 as compared with the commercially available perfluoropolyether Z-DOL (Comparative Example 11C) which is generally known as a lubricant for magnetic recording media applications shown as a comparative example. It can be seen that the temperature is higher than that of Z-TETRAOL (Comparative Example 12C) by 50 ° C or higher.

(Example 2C)
<Results of thermal stability measurement>
Bis (nonaflate butane sulfonyl) imide-8-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecene 5%, 10%, 20% Weight loss temperatures are 341.1 ° C and 372, respectively. It was 9.9 ° C and 396.3 ° C. It can be seen that the thermal stability is also improved as compared with the commercially available perfluoropolyether Z-DOL (Comparative Example 11C) and Z-TETRAOL (Comparative Example 12C).

(Example 3C)
<Results of thermal stability measurement>
Nonaflate Butane Sulfonic Acid-8-Octadecyl-1,8-diazabicyclo [5.4.0] -7-Undecene 5%, 10%, 20% Weight loss temperatures are 346.9 ° C and 373.1 ° C, respectively. 396.8 ° C., 150 ° C. or higher as compared with the commercially available perfluoropolyether Z-DOL (Comparative Example 11C) shown as a comparative example, which is generally known as a lubricant for magnetic recording media applications. It can also be seen that the temperature is 100 ° C. or higher as compared with Z-TETRAOL (Comparative Example 12C).

(Example 4C)
<Results of thermal stability measurement>
The 5%, 10% and 20% weight loss temperatures of bis (nonaflatebutanesulfonyl) imide-N-butyl-N-octadecylpyrrolidinium were 331.4 ° C, 360.2 ° C and 382.5 ° C, respectively. It was. It can be seen that the thermal stability is also improved as compared with the commercially available perfluoropolyether Z-DOL (Comparative Example 11C) and Z-TETRAOL (Comparative Example 12C).

(Example 5C)
<Results of thermal stability measurement>
The 5%, 10% and 20% weight loss temperatures of the bis (nonaflatebutanesulfonyl) imide-N-octadecylpyrrolidinium were 312.6 ° C., 334.4 ° C. and 355.5 ° C., respectively. It can be seen that the thermal stability is also improved as compared with the commercially available perfluoropolyether Z-DOL (Comparative Example 11C) and Z-TETRAOL (Comparative Example 12C).

(Example 6C)
<Results of thermal stability measurement>
The 5%, 10% and 20% weight loss temperatures of nonaflate butane sulfonic acid-N-octadecylpyrrolidinium were 339.4 ° C, 359.0 ° C and 377.3 ° C, respectively. It can be seen that the thermal stability is also improved as compared with the commercially available perfluoropolyether Z-DOL (Comparative Example 11C) and Z-TETRAOL (Comparative Example 12C).

(Example 7C)
<Results of thermal stability measurement>
Trifluoromethanesulfonic acid-8-octadecyl-1,8-diazabicyclo [5.4.0] -7-Undecenium 5%, 10%, 20% Weight loss temperatures are 319.2 ° C and 346.6 ° C, respectively. The temperature is 389.0 ° C., which is 140 ° C. or higher as compared with the commercially available perfluoropolyether Z-DOL (Comparative Example 11C) which is generally known as a lubricant for magnetic recording media applications shown as a comparative example. It can be seen that the temperature is 80 ° C. or higher even when compared with Z-TETRAOL (Comparative Example 12C).

(Example 8C)
<Results of thermal stability measurement>
Bis (Nonafluorobutane Sulfonyl) Imide-1-1'H, 1'H, 2'H, 2'H Heptadecafluorodecyl-3-octadecyl 5%, 10%, 20% weight loss temperature of imidazolium The temperature was 335.8 ° C, 358.5 ° C, and 377.7 ° C, respectively. It can be seen that the thermal stability is improved by 150 ° C. and 90 ° C. or higher, respectively, as compared with the commercially available perfluoropolyether Z-DOL (Comparative Example 11C) and Z-TETRAOL (Comparative Example 12C).

(Example 9C)
<Results of thermal stability measurement>
Bis (Nonafluorobutanesulfonyl) imide-1-1'H, 1'H, 2'H, 2'H Heptadecafluorodecyl-3-methylimidazolium 5%, 10%, 20% weight loss temperature The temperatures are 350.3 ° C. and 365.5 ° C., respectively, and 381.3 ° C., respectively, and the commercially available perfluoropolyether Z-DOL (comparative), which is generally known as a lubricant for magnetic recording media, shown as a comparative example. It can be seen that the temperature is 150 ° C. or higher as compared with Example 11C) and 90 ° C. or higher as compared with Z-TETRAOL (Comparative Example 12C).

(Example 10C)
<Results of thermal stability measurement>
Nonaflate Butane Sulfonic Acid-1-1'H, 1'H, 2'H, 2'H Heptadecafluorodecyl-3-methylimidazolium 5%, 10%, 20% Weight loss temperature is 373. It was 8 ° C., 389.3 ° C., and 401.7 ° C. It can be seen that the thermal stability is improved by 170 ° C. and 120 ° C. or higher, respectively, as compared with the commercially available perfluoropolyether Z-DOL (Comparative Example 11C) and Z-TETRAOL (Comparative Example 12C).

(Example 11C)
<Results of thermal stability measurement>
1,3-bis [bis (nonaflatebutanesulfonyl) imide-N-octadecylimidazolium)] 5%, 10%, 20% weight loss temperatures of propane were 352.3 ° C, 381.9 ° C, 401. It was 4 ° C. It can be seen that the thermal stability is improved by 170 ° C. and 120 ° C. or higher, respectively, as compared with the commercially available perfluoropolyether Z-DOL (Comparative Example 11C) and Z-TETRAOL (Comparative Example 12C).

(Comparative Example 1C)
<Results of thermal stability measurement>
Hexafluorocyclopropane-1,3-bis (sulfonyl) imide-6-octadecyl-1,8-diazabicyclo [5.4.0] -7-Undecenium 5%, 10%, 20% weight loss temperature, respectively It was 346.3 ° C., 384.1 ° C., and 414.0 ° C. Since it is an ionic liquid, it has high thermal stability even when compared with commercially available perfluoropolyether Z-DOL (Comparative Example 11C) and Z-TETRAOL (Comparative Example 12C).

(Comparative Example 2C)
<Results of thermal stability measurement>
5%, 10% and 20% weight loss temperatures of heptadecafluorooctanesulfonic acid-6-octadecil-1,8-diazabicyclo [5.4.0] -7-undecenium were 361.9 ° C and 382.7, respectively. The temperature was 403.5 ° C. Since it is an ionic liquid, it has high thermal stability even when compared with commercially available perfluoropolyether Z-DOL (Comparative Example 11C) and Z-TETRAOL (Comparative Example 12C).

(Comparative Example 3C)
<Results of thermal stability measurement>
Tris (trifluoromethanesulfonyl) methide-6-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenium 5%, 10%, 20% Weight loss temperature is 354.9 ° C., 385. It was 0 ° C. and 404.3 ° C. Since it is an ionic liquid, it has high thermal stability even when compared with commercially available perfluoropolyether Z-DOL (Comparative Example 11C) and Z-TETRAOL (Comparative Example 12C).

(Comparative Example 4C)
<Results of thermal stability measurement>
5%, 10%, 20% weight loss of hexafluorocyclopropane-1,3-bis (sulfonyl) imide-7-octadecyl-1,5,7-triazabicyclo [4.4.0] -5-decenium The temperatures were 288.4 ° C, 376.2 ° C and 412.1 ° C, respectively. Since it is an ionic liquid, it has high thermal stability even when compared with commercially available perfluoropolyether Z-DOL (Comparative Example 11C) and Z-TETRAOL (Comparative Example 12C).

(Comparative Example 5C)
<Results of thermal stability measurement>
5%, 10%, and 20% weight loss temperatures of -7-octadecyl-1,5,7-triazabicyclo [4.4.0] -5-decenium heptadecafluorooctanesulfonic acid were 356.1 ° C., respectively. , 380.4 ° C and 401.5 ° C. Since it is an ionic liquid, it has high thermal stability even when compared with commercially available perfluoropolyether Z-DOL (Comparative Example 11C) and Z-TETRAOL (Comparative Example 12C).

(Comparative Example 6C)
<Results of thermal stability measurement>
5%, 10% and 20% weight loss temperatures of hexafluorocyclopropane-1,3-bis (sulfonyl) imide-N-octadecylpyrrolidinium are 336.4 ° C., 358.4 ° C. and 379.4 ° C., respectively. Met. Since it is an ionic liquid, it has high thermal stability even when compared with commercially available perfluoropolyether Z-DOL (Comparative Example 11C) and Z-TETRAOL (Comparative Example 12C).

(Comparative Example 7C)
<Results of thermal stability measurement>
Nonaflate Butane Sulfonic Acid-1-1'H, 1'H, 2'H, 2'H Heptadecafluorodecyl-3-octadecyl The weight loss temperatures of 5%, 10% and 20% of imidazolium are 257. It was 5 ° C., 267.6 ° C., and 278.4 ° C. Since it is an ionic liquid, it has high thermal stability even when compared with commercially available perfluoropolyether Z-DOL (Comparative Example 11C) and Z-TETRAOL (Comparative Example 12C).

(Comparative Example 8C)
<Results of thermal stability measurement>
5%, 10% and 20% weight loss temperatures of bis (nonaflate butane sulfonyl) imide-1-butyl-3-n-octadecylimidazolium at 347.2 ° C, 367.0 ° C and 387.8 ° C, respectively. there were. Since it is an ionic liquid, it has high thermal stability even when compared with commercially available perfluoropolyether Z-DOL (Comparative Example 11C) and Z-TETRAOL (Comparative Example 12C).

(Comparative Example 9C)
<Results of thermal stability measurement>
5%, 10%, and 20% weight loss temperatures of 1,5-bis [bis (nonaflatebutanesulfonyl) imide-1-octadecylimidazolium] pentane are 360.1 ° C, 384.4 ° C, and 402.0, respectively. It was ° C. Since it is an ionic liquid, its thermal stability is 170 ° C. and 120 ° C. or higher, respectively, as compared with the commercially available perfluoropolyether Z-DOL (Comparative Example 11C) and Z-TETRAOL (Comparative Example 12C).

(Comparative Example 10C)
<Results of thermal stability measurement>
1,9-Bis [bis (nonafluorobutanesulfonyl) imide-1-octadecylimidazolium] 5%, 10% and 20% weight loss temperatures of nonane are 355.1 ° C, 381.0 ° C and 400.9, respectively. It was ° C. Since it is an ionic liquid, its thermal stability is 170 ° C. and 110 ° C. or higher, respectively, even when compared with commercially available perfluoropolyether Z-DOL (Comparative Example 11C) and Z-TETRAOL (Comparative Example 12C).

(Comparative Example 11C)
<Results of thermal stability measurement>
As Comparative Example 11C, as a result of measuring a commercially available perfluoropolyether Z-DOL having a hydroxyl group at the terminal and having a molecular weight of about 2000, the weight loss temperatures of 5%, 10% and 20% were 165.0 ° C., respectively. It was 197.0 ° C. and 226.0 ° C., and the weight loss was due to evaporation.

(Comparative Example 12C)
<Results of thermal stability measurement>
A commercially available perfluoropolyether (Z-TETRAOL) having a plurality of hydroxyl groups at the terminal and having a molecular weight of about 2000, which is generally used as a lubricant for a magnetic recording medium, was used as the lubricant of Comparative Example 12C. The 5%, 10%, and 20% weight loss temperatures of Z-TETRAOL are 240.0 ° C., 261.0 ° C., and 282.0 ° C., respectively, and the weight loss is due to evaporation as in Z-DOL.

The results of Examples 1C to 11C and Comparative Examples 1C to 12C are summarized in Table 4.

As described above, it can be seen that the ionic liquid lubricant is excellent in thermal stability as compared with the commercially available perfluoropolyethers of Comparative Examples 11C and 12C.
Regarding the thermal stability in the ionic liquid, those having an octadecyl-1,8-diazabicyclo [5.4.0] -7-undecene structure are described in Examples 1C to 3C. Comparisons can be made from Example 7C and Comparative Examples 1C to 3C. In this case, the weight loss temperature is higher in the comparative example at about 10 ° C. to 50 ° C. However, the ionic liquid having an octadecyl-1,8-diazabicyclo [5.4.0] -7-undecene structure has a considerably high weight loss temperature, and the weight loss temperature of 20% is close to 400 ° C., which is sufficient thermal stability. Is considered to have.
Further, regarding the ionic liquid having an N-octadecylpyrrolidine structure, Examples 4C to 6C and Comparative Example 6C are compared, and there is no significant difference in thermal stability between the Examples and the Comparative Examples. However, since it is an ionic liquid as described above, it exhibits extremely high thermal stability as compared with a commercially available perfluoropolyether structure.
Further, regarding the ionic liquid having an imidazole structure, Example 8C to Example 11C and Comparative Example 7C to Comparative Example 10C were compared, and the thermal stability was described in Example and Comparative Example except for Comparative Example 7C. There is no big difference. However, since it is an ionic liquid as described above, it exhibits extremely high thermal stability as compared with a commercially available perfluoropolyether structure.

(Example 1D to Example 11D, and Comparative Example 1D to Comparative Example 10D)
<Disc durability test>
A magnetic disk was prepared by applying a lubricant containing each of the ionic liquids of Examples 1A to 11A and Comparative Examples 1A to 10A. As shown in Tables 5-1 and 2, the CSS measurement of the magnetic disk exceeded 50,000 times, and the CSS measurement after the heating test also exceeded 50,000 times, showing excellent durability.

(Comparative Example 11D)
<Disc durability test>
The above-mentioned magnetic disk was prepared using a lubricant containing Z-DOL. As shown in Table 5-2, the CSS measurement of the magnetic disk exceeded 50,000 times, but the CSS measurement after the heating test was 12,000 times, and the durability was deteriorated by the heating test.

(Comparative Example 12D)
<Disc durability test>
The above-mentioned magnetic disk was prepared using a lubricant containing Z-TETRAOL. As shown in Table 5-2, the CSS measurement of the magnetic disk exceeded 50,000 times, but the CSS measurement after the heating test was 36,000 times, and the durability was deteriorated by the heating test.

The results of Examples 1D to 11D and Comparative Examples 1D to 12D are summarized in Tables 5-1 and 5-2.

(Example 1E to Example 11E, Comparative Example 1E to Comparative Example 12E)
The above-mentioned magnetic tape was prepared by using a lubricant containing the ionic liquids of Examples 1A to 11A, the ionic liquids of Comparative Examples 1A to 10A, Z-DOL, and Z-TETRAOL, respectively. Then, the following measurements were made. The results are shown in Table 6-1 and Table 6-2.
・ Friction coefficient of magnetic tape after 100 shuttle runs In an environment with a temperature of -5 ° C or a temperature of 40 ° C and a relative humidity of 90% ・ Still durability test In an environment with a temperature of -5 ° C or a temperature of 40 ° C, relative Humidity 30% environment ・ Shuttle durability test Under temperature -5 ℃ environment, or temperature 40 ℃, relative humidity 90% environment ・ Friction coefficient of magnetic tape after 100 shuttle runs after heating test Temperature -5 ℃ Environment or temperature 40 ° C, relative humidity 90% environment-Still durability test after heating test Temperature -5 ° C environment or temperature 40 ° C, relative humidity 30% environment-Shuttle durability test temperature after heating test In an environment of -5 ° C, or in a temperature of 40 ° C and relative humidity of 90%

The results of Examples 1E to 11E and Comparative Examples 1E to 12E are summarized in Tables 6-1 and 6-2.

In the table, ">60" for still durability indicates that it is over 60 minutes.
In the table, the shuttle durability ">200" indicates that the number of times exceeds 200 times.

The following was confirmed.
The lubricant-coated magnetic tapes containing the respective ionic liquids of Examples 1A to 11A were found to have excellent frictional properties, still durability, and shuttle durability.
It was found that the magnetic tape coated with the lubricant containing each of the ionic liquids of Comparative Examples 1A to 10A had excellent friction characteristics, still durability, and shuttle durability. Since this comparative example lubricant is an ionic liquid, it showed excellent magnetic tape durability even after the heating test.
It was found that the magnetic tape coated with Z-DOL had a large deterioration in still durability and shuttle durability.
It was found that the magnetic tape coated with Z-TETRAOL had a large deterioration in still durability and shuttle durability.

From Tables 6-1 and 6-2, it contains an ionic liquid having a conjugate base and a conjugate acid, and the conjugate acid has a group containing a linear hydrocarbon group having 6 or more carbon atoms. , The pKa of the acid that is the source of the conjugate base in acetonitrile is 10 or less, and the solubility of the ionic liquid in CF ₃ (CHF) ₂ CF ₂ CF ₃ is CF ₃ (CHF) ₂ CF ₂ CF. ₃ It was found that excellent heat resistance and durability in magnetic tapes and magnetic disks can be obtained by using an ionic liquid lubricant having an amount of 0.1 parts by mass or more with respect to 100 parts by mass. Furthermore, not only is it excellent in heat resistance and durability of the magnetic recording medium, but it also dissolves in a fluorine-based solvent, so there is no problem in the manufacturing process, especially when considering the application of a hard disk.
As is clear from the above description, the conjugate acid contains an ionic liquid having a conjugate base and a conjugate acid, and the conjugate acid has a group containing a linear hydrocarbon group having 6 or more carbon atoms. The pKa of the acid that is the source of the conjugate base in acetonitrile is 10 or less, and the solubility of the ionic liquid in CF ₃ (CHF) ₂ CF ₂ CF ₃ is CF ₃ (CHF) ₂ CF ₂ CF ₃ The ionic liquid lubricant having 0.1 parts by mass or more with respect to 100 parts by mass has a high decomposition temperature and 5%, 10%, and 20% weight loss temperatures, and is excellent in thermal stability. Further, even under high temperature conditions, excellent lubricity can be maintained as compared with conventional perfluoropolyether, and lubricity can be maintained for a long period of time. Therefore, a magnetic recording medium using a lubricant containing this ionic liquid can obtain extremely excellent running performance, abrasion resistance, and durability. In addition, since it is soluble in fluorine-based solvents, there is no problem in the manufacturing process, especially when considering the application of hard disks.

11 Substrate 12 Underlayer 13 Magnetic layer 14 Carbon protective layer 15 Lubricant layer 21 Substrate 22 Magnetic layer 23 Carbon protective layer 24 Lubricant layer 25 Backcoat layer

Claims (3)

Contains an ionic liquid having a conjugate base and a conjugate acid,
The conjugate acid is any of the following general formula (A), the following general formula (B), the following general formula (C), the following general formula (D), the following general formula (E), and the following general formula (F). Represented by
The conjugate base is represented by any of the following general formula (X), the following general formula (Y), and the following general formula (Z).
The pKa of the acid that is the source of the conjugate base in acetonitrile is 10 or less.
Lubricant characterized in that the solubility of the ionic liquid in CF ₃ (CHF) ₂ CF ₂ CF ₃ is 0.1 part by mass or more with respect to 100 parts by mass of CF ₃ (CHF) ₂ CF ₂ CF _3. Agent.
However, in the general formula (A), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, and R ² represents either a hydrogen atom or a hydrocarbon group.
However, in the general formula (B), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms.
However, in the general formula (C), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms.
However, in the general formula (D), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, and R ² represents either a hydrogen atom or a hydrocarbon group.
However, in the general formula (E), R ³ represents a hydrocarbon group, R ⁴ represents either a hydrogen atom or a hydrocarbon group, and R ⁵ is represented by the following general formula (IV). Represents a group .
_{- (CH 2) m - (} CF 2) n -CF 3 formula (IV)
In the general formula (IV), m represents an integer of 1 or more and 6 or less, n represents an integer of 3 or more and 20 or less, and m + n is 7 or more .
However, in the general formula (F), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, and n represents an integer of 1 or more and 3 or less.
However, in the general formula (X), l represents an integer of 1 or more and 12 or less.
However, in the general formula (Y), n represents an integer of 1 or more and 12 or less.
However, in the general formula (Z), n represents an integer of 0 or more and 6 or less. A magnetic recording medium having a non-magnetic support, a magnetic layer on the non-magnetic support, and the lubricant according to claim 1 on the magnetic layer. It has a conjugate base and a conjugate acid,
The conjugate acid is any of the following general formula (A), the following general formula (B), the following general formula (C), the following general formula (D), the following general formula (E), and the following general formula (F). Represented by
The conjugate base is represented by any of the following general formula (X), the following general formula (Y), and the following general formula (Z).
The pKa of the acid that is the source of the conjugate base in acetonitrile is 10 or less.
CF _{3 (CHF)} solubility 2 _CF 2 CF _{3 are,} CF _{3 (CHF)} against ₂ CF 2 CF 3 100 parts by weight, ionic liquids, characterized in that at least 0.1 part by weight.
However, in the general formula (A), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, and R ² represents either a hydrogen atom or a hydrocarbon group.
However, in the general formula (B), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms.
However, in the general formula (C), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms.
However, in the general formula (D), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, and R ² represents either a hydrogen atom or a hydrocarbon group.
However, in the general formula (E), R ³ represents a hydrocarbon group, R ⁴ represents either a hydrogen atom or a hydrocarbon group, and R ⁵ is represented by the following general formula (IV). Represents a group .
_{- (CH 2) m - (} CF 2) n -CF 3 formula (IV)
In the general formula (IV), m represents an integer of 1 or more and 6 or less, n represents an integer of 3 or more and 20 or less, and m + n is 7 or more .
However, in the general formula (F), R ¹ represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, and n represents an integer of 1 or more and 3 or less.
However, in the general formula (X), l represents an integer of 1 or more and 12 or less.
However, in the general formula (Y), n represents an integer of 1 or more and 12 or less.
However, in the general formula (Z), n represents an integer of 0 or more and 6 or less.