U.S. patent application number 12/093604 was filed with the patent office on 2009-10-29 for synthetic lubricating oil.
Invention is credited to You Honda, Naritoshi Kawata.
Application Number | 20090270286 12/093604 |
Document ID | / |
Family ID | 38023319 |
Filed Date | 2009-10-29 |
United States Patent
Application |
20090270286 |
Kind Code |
A1 |
Kawata; Naritoshi ; et
al. |
October 29, 2009 |
Synthetic Lubricating Oil
Abstract
The object of the present invention is to provide a synthetic
lubrication oil which shows low viscosity, is excellent in
viscosity properties at high temperature and shows stable
lubricating properties in a wide range of temperature. The
synthetic lubricating oil is one comprising an ionic liquid
containing an organic cation selected from the group consisting of
an imidazolium cation, a pyridinium cation, a quaternary ammonium
cation and a quaternary phosphonium cation and a
bis(fluorosulfonyl)imide anion, and one comprising an ionic liquid
composition which comprises an ionic liquid (A) containing a
1-ethyl-3-methylimidazolium cation and an ionic liquid (B1)
containing a 1-methyl-3-propylimidazolium cation and/or an ionic
liquid (B2) containing a 1-methyl-3-isopropylimidazolium
cation.
Inventors: |
Kawata; Naritoshi; (Osaka,
JP) ; Honda; You; (Osaka, JP) |
Correspondence
Address: |
ANTONELLI, TERRY, STOUT & KRAUS, LLP
1300 NORTH SEVENTEENTH STREET, SUITE 1800
ARLINGTON
VA
22209-3873
US
|
Family ID: |
38023319 |
Appl. No.: |
12/093604 |
Filed: |
November 10, 2006 |
PCT Filed: |
November 10, 2006 |
PCT NO: |
PCT/JP2006/322477 |
371 Date: |
May 14, 2008 |
Current U.S.
Class: |
508/244 ;
508/283; 508/388 |
Current CPC
Class: |
C10M 2215/2203 20130101;
C10M 2215/221 20130101; C10M 2215/023 20130101; C10N 2020/085
20200501; C10M 2215/224 20130101; C10M 2219/0406 20130101; C10M
2215/2245 20130101; C10N 2020/077 20200501; C10M 2215/02 20130101;
C10M 2219/044 20130101; C10N 2030/02 20130101; C10M 105/72
20130101 |
Class at
Publication: |
508/244 ;
508/283; 508/388 |
International
Class: |
C10M 133/40 20060101
C10M133/40; C10M 133/46 20060101 C10M133/46; C10M 135/08 20060101
C10M135/08 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 14, 2005 |
JP |
2005-328695 |
Sep 5, 2006 |
JP |
2006-240058 |
Claims
1. A synthetic lubricating oil comprising an ionic liquid
containing an organic cation selected from the group consisting of
an imidazolium cation, a pyridinium cation, a quaternary ammonium
cation and a quaternary phosphonium cation and a
bis(fluorosulfonyl)imide anion.
2. The synthetic lubricating oil of claim 1, wherein the organic
cation is an imidazolium cation.
3. The synthetic lubricating oil of claim 2, wherein the
imidazolium cation is a 1,3-disubstituted imidazolium cation in
which the substituents on the position-1 and the position-3 may be
same or different, or a 1,2,3-trisubstituted imidazolium cation in
which the substituents on the position-1, the position-2 and the
position-3 may be same or different.
4. A synthetic lubricating oil comprising an ionic liquid
composition comprising an ionic liquid (A) containing a
1-ethyl-3-methylimidazolium cation and an ionic liquid (B1)
containing a 1-methyl-3-propylimidazolium cation and/or an ionic
liquid (B2) containing a 1-methyl-3-isopropylimidazolium
cation.
5. The synthetic lubricating oil of claim 4, wherein an anion part
of the ionic liquid (A) and an anion part of the ionic liquid (B1)
and/or the ionic liquid (B2) are same.
6. The synthetic lubricating oil of claim 5, wherein the anion
parts of the ionic liquid (A) and the ionic liquid (B1) and/or the
ionic liquid (B2) are bis(fluorosulfonyl)imide or
(fluorosulfonyl)(trifluoromethanesulfonyl)imide.
7. The synthetic lubricating oil of claim 6, wherein a mixing ratio
(weight ratio) of the ionic liquid (A) to the ionic liquid (B1)
and/or the ionic liquid (B2) is (A):(B1) and/or (B2)=8:2 to
2:8.
8. The synthetic lubricating oil of claim 4, wherein the anion
parts of the ionic liquid (A) and the ionic liquid (B1) and/or the
ionic liquid (B2) are bis(fluorosulfonyl)imide or
(fluorosulfonyl)(trifluoromethanesulfonyl)imide.
9. The synthetic lubricating oil of claim 4, wherein a mixing ratio
(weight ratio) of the ionic liquid (A) to the ionic liquid (B1)
and/or the ionic liquid (B2) is (A):(B1) and/or (B2)=8:2 to
2:8.
10. The synthetic lubricating oil of claim 5, wherein a mixing
ratio (weight ratio) of the ionic liquid (A) to the ionic liquid
(B1) and/or the ionic liquid (B2) is (A):(B1) and/or (B2)=8:2 to
2:8.
Description
RELATED APPLICATION
[0001] This application is a U.S. national phase application under
35 U.S.C. .sctn.371 of International Application No.
PCT/JP2006/322477 filed Nov. 10, 2006 which claims priority of
Japanese Patent Application No. 2005-328695 filed Nov. 14, 2005 and
Japanese Patent Application No. 2006-240058 filed Sep. 5, 2006.
TECHNICAL FIELD
[0002] The present invention relates to a synthetic lubricating oil
comprising an ionic liquid selected from an organic cation and a
bis(fluorosulfonyl)imide anion, and to a synthetic lubricating oil
comprising an ionic liquid composition which is a mixture of two or
more ionic liquids containing a 1,3-substituted imidazolium
cation.
BACKGROUND ART
[0003] As a lubricating oil used in a machinery installment, a
power transmission device, a metallurgical processing oil, grease
and the like, base oil selected from a poly .alpha.-olefin, a
diester, a polyol ester, silicone and the like as the best
ingredient has so far been used under optionally mixing with a
suitable additive. However, those lubricating oils are accompanied
with a danger of flash ignition or evaporation under specific
conditions such as high temperature and highly vacuum pressure, and
thus more suitable lubricating oil has been desired. Further, in
accordance with high functionality and high efficacy of a device, a
lubricating oil having more excellent anti-oxidation property,
anti-evaporation property and long-released excellent lubricating
property has been desired.
[0004] As means for solving the above problems, it is reported in
R. A. Reich et al., Journal of the Society of Tribologists and
Lubrication Engineers, July 2003, p. 16 to 21, for instance, that a
compound comprising a combination of an organic cation and an
inorganic anion (ionic liquid, melted salt at normal temperature)
can be adopted as lubricating oil, and it has recently been known
that the ionic liquid is possibly usable as a material of a
lubricating oil because the ionic liquid is excellent in
non-volatility, stability in a wide temperature range and
fire-resistance, and also it has a high viscosity index and
sufficient properties of a coefficient of friction and an abrasion
trace diameter which are required for lubricating oil.
[0005] However, many of the ionic liquids have generally show high
viscosity, and thus it is necessary for practical use as a
lubricating oil to find out an ionic liquid having low viscosity,
and under the situation, further development has been
continued.
[0006] And, in a Japanese Patent Publication No. 2005-89667, an
ionic liquid containing bis(trifluoromethanesulfonyl)imide anion as
an anion is mentioned as an ionic liquid having low viscosity.
However, it has been said that the ionic liquid comprising this
combination of an anion is not sufficient in reduction of
viscosity.
DISCLOSURE OF INVENTION
[0007] Under the situation, the object of the present invention is
to provide a synthetic lubricating oil having a stable lubricating
property in a wide temperature range.
[0008] Thus, the present inventors have made extensive study under
considering the above situation to find surprisingly that an ionic
liquid having remarkably low viscosity and excellent viscosity
stability can be obtained by using a bis(fluorosulfonyl)imide anion
as an anion seed in an ionic liquid using an organic cation
selected from an imidazolium cation, a pyridinium cation, a
quaternary ammonium cation and a quaternary phosphonium cation and
this ionic liquid can suitably be used as a synthetic lubricating
oil.
[0009] Further, it is found that an ionic liquid composition having
a low viscosity and excellent viscosity stability and moreover
having a lower melting point compared with a single use can be
obtained by mixing an ionic liquid with an ionic liquid containing
an imidazolium cation having a specific alkyl group of relatively
short alkyl chain and at the same time by incorporating therein two
or more kind of compounds having an eutectic point, and
consequently the present invention has been completed.
[0010] Namely, the present invention relates to a synthetic
lubricating oil comprising an ionic liquid composition which
comprises an ionic liquid (A) containing an organic cation selected
from the group consisting of an imidazolium cation, a pyridinium
cation, a quaternary ammonium cation and a quaternary phosphonium
cation and a bis(fluorosulfonyl)imide anion and an ionic liquid
(B1) containing a 1-ethyl-3-methylimidazolium cation, and an ionic
liquid (B2) containing a 1-methyl-3-propylimidazolium cation and/or
a 1-methyl-3-isopropylimidazolium cation.
[0011] The ionic liquid and the ionic liquid composition used in
the present invention are useful as lubricating oil which is
excellent in anti-abrasion property and further has stable
flowability, and viscosity characteristics required for lubricating
oil, and still further has stable lubricating properties in a wide
temperature range and a wide using condition.
BEST MODE FOR CARRYING OUT THE INVENTION
[0012] In the following, the present invention is explained in
details.
[0013] In the following, the ionic liquid of the present invention
means an ionic substance which is in melted state at normal
temperature (25.degree. C.).
[0014] The present invention relates to a synthetic lubricating oil
comprising an ionic liquid composition which comprises an organic
cation selected from the group consisting of an imidazolium cation,
a pyridinium cation, a quaternary ammonium cation and a quaternary
phosphonium cation and a bis(fluorosulfonyl)imide anion and to a
synthetic lubricating oil comprising an ionic liquid (A) containing
a 1-ethyl-3-methylimidazolium cation, and an ionic liquid (B1)
containing a 1-methyl-3-propylimidazolium cation and/or an ionic
liquid (B2) containing a 1-methyl-3-isopropylimidazolium
cation.
[0015] Explanation is given first on the synthetic lubricating oil
comprising an ionic liquid which comprises an organic cation
selected from the group consisting of an imidazolium cation, a
pyridinium cation, a quaternary ammonium cation and a quaternary
phosphonium cation, and a bis(fluorosulfonyl)imide anion.
[0016] The organic cation used in the present invention is
exemplified by an imidazolium cation, a pyridinium cation, a
quaternary ammonium cation and a quaternary phosphonium cation. By
combining the organic cation with a bis(fluorosulfonyl)imide anion,
viscosity of the ionic liquid as a synthetic lubricating oil can be
reduced to a great extent.
[0017] The imidazolium cation is not specifically limited and can
be exemplified by one having a structure shown by the following
general formula (I).
##STR00001##
(in the formula (I), the substituents R.sup.1 to R.sup.5 are each
independently a hydrogen atom, a halogen atom, a straight chained
or branched alkyl group, an alkenyl group, an alkinyl group, an
alkoxyl group or an acyl group, which has 1 to 16 carbon atoms, or
an amide group, a cyano group, a nitro group, or an amino group,
and the alkyl group, the alkenyl group, the alkinyl group, the
alkoxyl group and the acyl group may contain a hetero atom selected
from N, S and O, and further may contain a conjugate or independent
double bond or triple bond.).
[0018] In a case where the substituents R.sup.1 to R.sup.5 are an
alkyl group, an alkenyl group, an alkinyl group, an alkoxyl group
or an acyl group, a carbon atom number thereof is preferably 1 to
16, particularly preferably 1 to 12, and still particularly
preferably 1 to 6. Those substituents may be straight chained or
branched, and a carbon atom number over the above maximum value is
not preferable because of trend of viscosity increase by
intermolecular interaction on side chains.
[0019] The above alkyl group, alkenyl group, alkinyl group, alkoxyl
group and acyl group may contain a hetero atom selected from N, S
and O, and the number of the hetero atom to be contained is not
specifically limited. Further, they may contain a conjugate or
independent double bond or triple bond, and the number of those
unsaturated bonds is not specifically limited.
[0020] Those alkyl groups are specifically exemplified by a methyl
group, an ethyl group, a propyl group, an isopropyl group, a butyl
group, an isobutyl group, a secondary butyl group, a tertiary butyl
group, a pentyl group, a hexyl group, a cyclopropyl group, a
cyclopentyl group, a cyclohexyl group, etc. The alkenyl group is
exemplified by a vinyl group, an allyl group, an 1-propenyl group,
an isopropenyl group, a 2-butenyl group, an 1,3-butadienyl group, a
2-pentenyl group, a 2-hexenyl group, etc. Further, the alkinyl
group is exemplified by an ethynyl group, an 1-propinyl group, a
2-propinyl group, etc., and the alkoxyl group is exemplified by a
methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy
group, a t-butoxy group, etc., the acyl group is exemplified by an
acetyl group, a propionyl group, a butylyl group, a benzoyl group,
etc., and the amino group is exemplified by an N,N-dimethylamino
group, an N,N-diethylamino group, etc. From a viewpoint of
industrial use, easy decomposition by enzymes and increased
biodegrability are valuable, and thus an alkoxyl group, an acyl
group, an amide group, a cyano group, a nitro group, an amino
group, etc. can be mentioned.
[0021] As the imidazolium cation shown by the above formula (I),
1,3-substituted imidazolium cation, and 1,2,3-substituted
imidazolium cation is preferably used from a viewpoint of easy
synthesis. The substituent in the derivatives may be same or
different, and a substituent which may contain a multiple bond or a
branched chain is preferable.
[0022] The above substituent is same with one in the above general
formula (I), and one optionally selected therefrom is used.
[0023] Further, in the present invention, a pyridinium cation, a
quaternary ammonium cation and a quaternary phosphonium cation are
mentioned as well as the above imidazolium cation, and the
pyridinium cation is exemplified by a pyridinium cation substituted
by an alkyl group of 1 to 16 carbon atoms such as
N-methylpyridinium, N-ethylpyridinium, N-butylpyridinium and
N-propylpyridinium.
[0024] The quaternary ammonium cation is exemplified by an ammonium
cation substituted by an alkyl group of 1 to 16 carbon atoms such
as tetramethylammonium, tetraethylammonium and
tetrabutylammonium.
[0025] The quaternary phosphonium cation is exemplified by a
phosphonium cation substituted by an alkyl group of 1 to 16 carbon
atoms such as tetramethylphosphonium, tetraethylphosphonium and
tetrabutylphosphonium.
[0026] And, in the present invention, the anion used as an anion
part constituting the ionic liquid together with the above organic
cation is a bis(fluorosulfonyl)imide anion, and by using this
anion, an ionic liquid having remarkably low viscosity and
excellent viscosity stability can be obtained.
[0027] A method for producing the ionic liquid of the present
invention is not specifically limited, and a conventional method
such as an ion exchange method or a metathesis reaction can be
applied. For instance, the ionic liquid can be obtained by an anion
exchange reaction using a halogenated salt of an organic cation to
be used and an alkaline metal salt of a bis(fluorosulfonyl)imide
anion. The halogen in the halogenated salt is exemplified by
chlorine or bromine. The alkaline metal in the alkaline metal salt
is exemplified by sodium, potassium, etc.
[0028] Amounts of the halogenated salt of the organic cation and
the alkaline metal salt of a bis(fluorosulfonyl)imide anion to be
used in the above reaction are not specifically limited, and 0.5 to
2 equivalents, still preferably 0.8 to 1.2 equivalent of the
alkaline metal salt of bis(fluorosulfonyl)imide anion relative to
the halogenated salt of the organic cation is preferable. In a case
of over the above range, economical effect tends to be lowered
because the amount over the range does not give influence upon a
reaction yield, and in a case of less than the range, on the other
hand, a large amount of non-reacted starting material remains to
bring about tendency of lowering a reaction yield.
[0029] The synthetic lubricating oil containing the ionic liquid
comprising the above organic cation and bis(fluorosulfonyl)imide
anion may contain, as well as the above ionic liquid, a base oil
for a lubrication oil, which has been conventionally used, and
further optionally other additives such as an anti-rusting agent
and a flow-point depressant can be used. An amount of the additives
is not specifically limited so far as the effect of the present
invention is not disturbed, and it is preferably 0.001 to 50% by
weight relative to the ionic liquid in order to utilize the
characteristics owned by the ionic liquid itself.
[0030] Then, explanation is given on the synthetic lubricating oil
comprising the ionic liquid composition which comprises the ionic
liquid (A) containing a 1-ethyl-3-methylimidazolium cation and the
ionic liquid (B1) containing a 1-methyl-3-propylimidazolium cation
and/or the ionic liquid (B2) containing a
1-methyl-3-iospropylimidazolium cation.
[0031] Those ionic liquid compositions have been found as a result
of studying combinations of ionic liquids containing various kind
of imidazolium cation. The compositions comprising combinations of
those ionic liquids have low viscosity and excellent viscosity
stability, and further have lower viscosity than each of the ionic
liquids themselves, and thus it has been found that those
compositions can be used as lubricating oil at a low temperature in
a wider range.
[0032] The anion parts of the ionic liquids (A), (B1) and (B2) used
in the present invention are not specifically limited, and anions
so far used in conventional ionic liquids can be used. Among them,
use of a hydrophobic organic anion or inorganic anion is preferable
from a viewpoint of keeping hydrophobicity, and as the hydrophobic
organic anion, a bis(trifluoromethanesulfonyl)imide anion, a
(fluorosulfonyl)(trifluoromethanesulfonyl)imide anion, a
(trifluoroacetyl) (trifluoromethanesulfonyl)imide anion, etc. are
preferably used, and as the hydrophobic inorganic anion, a
hexafluorophosphate anion, a bis(fluorosulfonyl)imide anion, etc.
are preferably used, among which a bis(fluorosulfonyl)imide anion
is most preferably used.
[0033] The anion parts of each ionic liquid constituting the ionic
liquid composition of the present invention may be same with or
different from each other, and the same anion parts are
particularly desirable because of easier production compared with
different anion parts.
[0034] A mixing ratio (weight ratio) of the ionic liquid (A) to the
ionic liquid (B1) and/or the ionic liquid (B2) to be used in the
present invention can be selected suitably according to the desired
viscosity and low temperature for its use, and generally, a ratio
(A):(B1) and/or (B2)=8:2 to 2:8 is preferable. Over the maximum in
the ionic liquid (A) tends to cause increase of a melting point,
and less than the range tends to cause increase of viscosity.
[0035] Particularly in a case of incorporating the ionic liquid (A)
and the ionic liquid (B1), its mixing ratio (weight ratio) of
(A):(B1)=7:3 to 2:8 is preferable, and in a case of incorporating
the ionic liquid (A) and the ionic liquid (B2), its mixing ratio
(weight ratio) of (A):(B2)=8:2 to 6:4 is preferable. Over the
maximum in the ionic liquid (A) tends to cause increase of a
melting point, and less than the range tends to cause increase of
viscosity.
[0036] In the ionic liquid composition of the present invention, it
is possible to co-use the ionic liquid (A) with (B1), co-use the
ionic liquid (A) with (B2) and to co-use of the ionic liquid (A)
with (B1) and (B2), and also it is possible to co-use an optional
ionic liquid (C) other than the ionic liquids (A), (B1) and (B2) in
a range not inhibiting the effect of the present invention. The
optional ionic liquid (C) is exemplified by an ionic liquid
containing a 1-allyl-3-alkylimidazolium cation, an ionic liquid
containing a 1,3-diallylimidazolium cation, an ionic liquid
containing a 1,3-dimethylimidazolium cation, etc., but not limited
thereto.
[0037] An amount of the ionic liquid (C) is, in general, preferably
0 to 20% by weight, more preferably 0 to 10% by weight.
[0038] A method for producing the ionic liquid (A), (B1), (B2) and
(C) is not specifically limited, and a conventional method such as
an anion exchange method, an acid ester method, a neutralizing
method, etc. can be applied. For instance, they can be produced by
alkylating with the use of N-alkyl imidazole and an alkylating
agent such as an alkyl halide, and then conducting an anion
exchange reaction using an alkyl metal salt of
bis(fluorosulfonyl)imide.
[0039] The synthetic lubricating oil containing the ionic liquid
composition may contain a conventional base oil of a lubricating
oil as well as the above ionic liquid component, and further
optionally other additives such as an anti-rusting agent and a
flow-point depressant can be used. An amount of the additives to be
used is not specifically limited so far as not disturbing the
effect of the present invention, and preferably 0.001 to 50% by
weight relative to the above ionic liquid in order to utilize the
characteristics owned by the ionic liquid itself.
[0040] In this way as above, the synthetic lubricating oil
comprising the ionic liquid or the ionic liquid composition of the
present invention can be produced.
[0041] Viscosity of the synthetic lubricating oil of the present
invention is, in general, preferably 30 mPas or lower at 25.degree.
C., still preferably 20 mPas or lower. Over the maximum of
viscosity is not preferable because energy loss is caused by
viscosity of the lubricating oil itself, and the minimum of the
viscosity is generally 2 mPas, and less than the minimum tends to
fly easily due to low viscosity.
[0042] Further, the kinematic viscosity of the synthetic
lubricating oil of the present invention is preferably 2 to 20
mm.sup.2/sec at 40.degree. C., still preferably 4 to 10
mm.sup.2/sec, and the kinematic viscosity at 100.degree. C. is
preferably 1 to 13 mm.sup.2/sec, still preferably 2 to 7
mm.sup.2/sec. Over the maximum in each temperature tends to cause
energy loss by viscosity of the lubricating oil itself, and less
than the minimum tends to fly easily due to low viscosity.
[0043] Viscosity index of the synthetic lubricating oil is
preferably 180 or more, still preferably 200 or more, particularly
preferably 220 or more. The maximum viscosity index is generally
700. Herein, viscosity index means an index showing a relation of
temperature and viscosity, and calculated by a method stipulated in
JIS K2283 (a test method for kinematic viscosity of crude oil and
petroleum products and a viscosity index calculation method of
petroleum products).
[0044] Higher viscosity index means less change by temperature, and
thus means that the product is excellent as a lubricating oil.
[0045] As the objects to be applied by the lubricating oil, there
can be imaged those wherein high absolute viscosity is important
and those wherein other properties such as contact angle to a metal
is considered to be more important than absolute viscosity. In such
cases, upon necessity, the properties are controlled by selecting
the organic cation among an imidazolium cation, a pyridinium
cation, a quaternary ammonium cation and a quaternary phosphonium
cation and further optionally changing the substituent. Also in
this case, the above viscosity index is a property considered to be
important. Less than the minimum viscosity index tends to bring
about too much high changing degree of viscosity by
temperature.
[0046] The synthetic lubricating oil of the present invention has
excellent viscosity properties at low viscosity and high
temperature, and is excellent in non-volatility, heat stability and
other properties, and thus it has possibility of using in a wide
range as lubricating oil for machinery installments such as
automobiles and electrical products, power transmission devices and
precision machines, as metallurgical processing oil, as lubricating
oil under special conditions, and the like.
EXAMPLE
[0047] In the following, the present invention is further explained
referring to Examples, but the present invention is not limited to
the following Examples unless it is beyond its gist. In Examples,
"part" and "%" mean on the basis of weight unless otherwise stated.
Viscosity was obtained by the following method.
[0048] Conditions for measuring viscosity are as follows.
Machine: AR-1000 type rotary rheometer (TA Instruments). Measuring
method: The machine was set forth at 25.degree. C., and 0.6 ml
sample was put on a sample desk, and a cone was set forth, and
viscosity upon rotating the cone at predetermined force (20 Pa) was
measured.
[0049] The kinematic viscosity at 40.degree. C. and 100.degree. C.
was obtained by measuring viscosity at each of the above
temperature using the above machine and measuring method and
calculating from thus obtained viscosity. Further, the viscosity
index was obtained by calculating from the kinematic
viscosities.
Synthesis Example 1
[0050] In a flask equipped with a refluxing column were charged
19.1 g (0.10 mol) of 1-ethyl-3-methylimidazolium bromide and 20 ml
of water, and further 21.9 g (0.10 mol) of potassium salt of
bis(fluorosulfonyl)imide, followed by stirring at 40.degree. C. for
5 hours. After the reaction, 80 ml of methylene chloride was added,
followed by well stirring and fractionating. The methylene chloride
layer was washed five times each with 40 ml of water, and the
methylene chloride layer is concentrated under reduced pressure to
give 23.8 g (0.08 mol, yield: 81.8%) of 1-ethyl-3-methylimidazolium
bis(fluorosulfonyl)imide.
Synthesis Example 2
[0051] The same procedure as the above Synthesis example 1
excepting using 20.5 g of 1-methyl-3-propylimidazolium bromide in
place of 19.1 g of 1-ethyl-3-methylimidazolium bromide was
conducted to give 27.5 g (0.09 mol, yield: 90.1%) of
1-methyl-3-propylimidazolium bis(fluorosulfonyl)imide. Viscosity of
this compound was 29 mPas (25.degree. C.).
Synthesis Example 3
[0052] The same procedure as the above Synthesis example 1
excepting using 20.5 g of 1-methyl-3-isopropylimidazolium bromide
in place of 19.1 g of 1-ethyl-3-methylimidazolium bromide was
conducted to give 27.1 g (0.09 mol, yield: 88.8%) of
1-methyl-3-isopropylimidazolium bis(fluorosulfonyl) imide.
Viscosity of this compound was 27 mPas (25.degree. C.).
Example 1
[0053] Result of measuring various properties of
1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide in the
Synthesis example 1 is shown in Table 1.
Comparative Example 1
[0054] 11.0 Grams (60.6 mmol) of 1-ethyl-3-methylimidazolium
bromide obtained by the same method as Example 1 was reacted with
20.3 g (63.7 mmol) of potassium salt of
bis(trifluoromethanesulfonyl)imide anion in 20 g of water-methylene
chloride at 40.degree. C. for 4 hours, and an aqueous layer was
fractionated by a separating funnel and discarded, and an organic
layer was washed with water, followed by drying under reduced
pressure to give 22.5 g (57.6 mmol, yield: 95.0%) of
1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide.
[0055] Measurement of properties of the obtained
1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide was
conducted by the same manner as the Example 1. The result is shown
in Table 1.
Comparative Example 2
Poly.alpha.-Olefin
[0056] Properties were measured by the same manner as the Example 1
using poly.alpha.-olefin (SYNFLUID 801 (Chevron phillips). The
result is shown in Table 1.
Comparative Example 3
Diester
[0057] Properties were measured by the same manner as the Example 1
using diester (dioctyl adipate: Plasthall DOA (The C.P. Hall)). The
result is shown in Table 1.
Comparative Example 4
Polyol Ester
[0058] Properties were measured by the same manner as the Example 1
using polyol ester (polyester (trivalent): KAOLUBE 190 (Kao
Corporation)). The result is shown in Table 1.
Comparative Example 5
Liquid Paraffin
[0059] Properties were measured by the same manner as the Example 1
using liquid paraffin (Cosmo Neutral 150: (Cosmo Oil Lubricants co
LTD)). The result is shown in Table 1.
TABLE-US-00001 TABLE 1 Kinematic Kinematic Viscosity viscosity
viscosity (25.degree. C., (40.degree. C., (100.degree. C.,
Viscosity mPa s) mm.sup.2/s) mm.sup.2/s) index Ex. 1 19 9.4 4.9 623
Com. Ex. 1 28 12 3.7 206 Com. Ex. 2 62 46 7.8 130 Com. Ex. 3 36 25
5.2 140 Com. Ex. 4 65 48 9.7 151 Com. Ex. 5 44 33 5.6 108
Examples 2 to 7
[0060] Using 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide
in the Synthesis example 1 as the ionic liquid (A) and
1-methyl-3-propylimidazolium bis(fluorosulfonyl)imide in the
Synthesis example 2 as the ionic liquid (B1), ionic liquid
compositions of the formulations in Table 2 were produced. Result
of measuring properties thereon is shown in Table 2.
TABLE-US-00002 TABLE 2 Ionic Ionic liquid liquid Kinematic
Kinematic (A) (B1) Viscosity viscosity viscosity EMIFSI MPIFSI
(25.degree. C., (40.degree. C., (100.degree. C., Viscosity (%) (%)
mPa s) mm.sup.2/s) mm.sup.2/s) index Ex. 2 80 20 20 10.3 4.7 503
Ex. 3 70 30 21 10.7 4.7 473 Ex. 4 60 40 22 11.1 4.8 463 Ex. 5 50 50
22 11.5 4.8 438 Ex. 6 40 60 23 11.8 4.9 437 Ex. 7 20 80 25 12.2 5.4
490
EMIFSI: 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide
MPIFSI: 1-methyl-3-propylimidazolium bis(fluorosulfonyl)imide
Examples 8 and 9
[0061] Using 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide
in the Synthesis example 1 as the ionic liquid (A) and
1-methyl-3-isopropylimidazolium bis(fluorosulfonyl)imide in the
Synthesis example 3 as the ionic liquid (B2), ionic liquid
compositions were produced. Result of measuring properties thereon
is shown in Table 3.
TABLE-US-00003 TABLE 3 Ionic Ionic liquid liquid Kinematic
Kinematic (A) (B2) Viscosity viscosity viscosity Vis- EMIFSI
MiPIFSI (25.degree. C., (40.degree. C., (100.degree. C., cosity (%)
(%) mPa s) mm.sup.2/s) mm.sup.2/s) index Ex. 8 80 20 20 10.3 4.7
503 Ex. 9 60 40 21 10.9 4.8 477 EMIFSI: 1-ethyl-3-methylimidazolium
bis(fluorosulfonyl)imide MiPIFSI: 1-methyl-3-isopropylimidazolium
bis(fluorosulfonyl)imide
[0062] As understood from results of Table 1 to Table 3, the
synthetic lubricating oil of the present invention, which comprises
the specific organic cation and bis(fluorosulfonyl)imide anion and
the synthetic lubricating oil containing the ionic liquid
composition comprising a mixture of two or more ionic liquids
containing 1,3-substituted imidazolium cation has lower viscosity
and higher viscosity index compared with an ionic liquid comprising
a bis(trifluoromethyl sulfonyl)imide anion which has been known as
being low viscosity, and other conventional base oil, and thus they
are remarkably excellent in properties as a synthetic lubricating
oil.
[0063] Further, by making the cation easily degradable by
introducing a substituent for increasing biodegradability, the
remaining anion becomes an inorganic compound and thus no attention
to biodegradability of the anion is necessary, and consequently the
oil becomes suitable also from environmental point of view.
INDUSTRIAL APPLICABILITY
[0064] The synthetic lubricating oil of the present invention is
suitable as a lubricating oil for machinery installments such as
automobiles, marine structures and electrical products, a
lubricating oil for power transmission devices and precision
machines, metallurgical processing oil, a lubricating oil under
special conditions, and the like.
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