U.S. patent application number 10/491238 was filed with the patent office on 2005-06-16 for dibasic acid diesters.
Invention is credited to Fukuda, Yukitoshi, Ito, Katsuhiro, Osada, Kazuyasu, Shimizu, Ikuo.
Application Number | 20050130850 10/491238 |
Document ID | / |
Family ID | 19130811 |
Filed Date | 2005-06-16 |
United States Patent
Application |
20050130850 |
Kind Code |
A1 |
Fukuda, Yukitoshi ; et
al. |
June 16, 2005 |
Dibasic acid diesters
Abstract
The present invention provides dibasic acid diesters, which are
suitable for use in lubricating base oils, etc. and excellent in
hydrolysis resistance, etc., represented by general formula (I): 1
(wherein R.sup.2 and R.sup.3, which may be the same or different,
each represent lower alkyl; and R.sup.1 and R.sup.4, which may be
the same or different, each represent alkyl having 7 or more carbon
atoms).
Inventors: |
Fukuda, Yukitoshi;
(Yokkaichi-shi, JP) ; Shimizu, Ikuo;
(Yokkaichi-shi, JP) ; Ito, Katsuhiro;
(Yokkaichi-shi, JP) ; Osada, Kazuyasu;
(Yokkaichi-shi, JP) |
Correspondence
Address: |
FITZPATRICK CELLA HARPER & SCINTO
30 ROCKEFELLER PLAZA
NEW YORK
NY
10112
US
|
Family ID: |
19130811 |
Appl. No.: |
10/491238 |
Filed: |
November 15, 2004 |
PCT Filed: |
October 10, 2002 |
PCT NO: |
PCT/JP02/10528 |
Current U.S.
Class: |
508/110 |
Current CPC
Class: |
C10N 2020/081 20200501;
C10N 2030/66 20200501; C10N 2030/64 20200501; C10M 2207/2825
20130101; C10M 105/36 20130101; C10M 2207/345 20130101; C07C 69/34
20130101; C10M 2207/2855 20130101 |
Class at
Publication: |
508/110 |
International
Class: |
C10M 101/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 10, 2001 |
JP |
2001-312099 |
Claims
1. A dibasic acid diester represented by general formula (I):
3(wherein R.sup.2 and R.sup.3, which may be the same or different,
each represent lower alkyl; and R.sup.1 and R.sup.4, which may be
the same or different, each represent alkyl having 7 or more carbon
atoms).
2. The dibasic acid diester according to claim 1, wherein R.sup.1
and R.sup.4 each are alkyl having 7 to 40 carbon atoms.
3. A lubricating base oil comprising the dibasic acid diester
according to claim 1 or 2.
4. A lubricating oil comprising the lubricating base oil according
to claim 3.
Description
TECHNICAL FIELD
[0001] The present invention relates to dibasic acid diesters
suitable for use in lubricating base oils, etc.
BACKGROUND ART
[0002] As base oils for lubricating oils and grease, those having a
high stability and a long life are desirable.
[0003] Known examples of the base oils for lubricating oils or
grease include those comprising dibasic acid diesters. As the
lubricating oil whose base oil is a dibasic acid diester,
WO97/21792 discloses a lubricating oil whose base oil is an
alicyclic polycarboxylic acid ester, and Japanese Published
Unexamined Patent Application No. 2001-89776 discloses a
lubricating oil for a freezer whose base oil is
1,2-cyclohexanedicarboxylic acid diester. However, neither of the
above lubricating oils whose base oil is a polycarboxylic acid
diester is practically satisfactory in respect of hydrolysis
resistance.
DISCLOSURE OF THE INVENTION
[0004] An object of the present invention is to provide dibasic
acid diesters, which are suitable for use in lubricating base oils,
etc. and excellent in hydrolysis resistance, etc.
[0005] The present invention provides the following (1) to (4).
[0006] (1) A dibasic acid diester represented by general formula
(I): 2
[0007] (wherein R.sup.2 and R.sup.3, which may be the same or
different, each represent lower alkyl; and R.sup.1 and R.sup.4,
which may be the same or different, each represent alkyl having 7
or more carbon atoms).
[0008] (2) The dibasic acid diester according to (1), wherein
R.sup.1 and R.sup.4 each are alkyl having 7 to 40 carbon atoms.
[0009] (3) A lubricating base oil comprising the dibasic acid
diester according to (1) or (2).
[0010] (4) A lubricating oil comprising the lubricating base oil
according to (3).
[0011] Hereinafter, the dibasic acid diesters represented by
general formula (I) may be referred to as Compounds (I).
[0012] In the definitions of the groups in general formula (I), the
lower alkyl includes straight-chain or branched alkyl groups having
1 to 8 carbon atoms, such as methyl, ethyl, propyl, isopropyl,
butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isoamyl, neopentyl,
hexyl, heptyl, octyl, isooctyl and 2-ethylhexyl. As R.sup.2 and
R.sup.3, alkyl having 1 to 4 carbon atoms is preferred, and ethyl
is more preferred.
[0013] The alkyl having 7 or more carbon atoms includes
straight-chain or branched ones such as heptyl, octyl, 2-octyl,
3-octyl, isooctyl, 2-ethylhexyl, 4-methyl-3-heptyl,
2-propyl-1-pentyl, 2,4,4-trimethyl-1-pentyl, 2,2-dimethyl-3-hexyl,
2,3-dimethyl-2-hexyl, 2,5-dimethyl-2-hexyl, 2,5-dimethyl-3-hexyl,
3,4-dimethyl-3-hexyl, 3,5-dimethyl-3-hexyl,
3-ethyl-2-methyl-3-pentyl, 2-methyl-2-heptyl, 3-methyl-3-heptyl,
4-methyl-4-heptyl, 5-methyl-1-heptyl, 5-methyl-2-heptyl,
5-methyl-3-heptyl, 6-methyl-2-heptyl, 6-methyl-3-heptyl, nonyl,
2-nonyl, 3-nonyl, 4-nonyl, 5-nonyl, 2-methyl-3-octyl,
6-methyl-1-octyl, 3,5,5-trimethyl-1-hexyl, 2,6-dimethyl-4-heptyl,
3-ethyl-2,2-dimethyl-3-pentyl, decyl, 2-decyl, 3-decyl, 4-decyl,
5-decyl, 3,7-dimethyl-1-octyl, 3,7-dimethyl-3-octyl, undecyl,
2-undecyl, 3-undecyl, 4-undecyl, 5-undecyl, 6-undecyl, dodecyl,
2-dodecyl, 2-butyl-1-octyl, tridecyl, 2-tridecyl, tridecyl,
tetradecyl, 2-tetradecyl, 7-tetradecyl, 7-ethyl-2-methyl-4-undecyl,
pentadecyl, hexadecyl, 2-hexadecyl, 2-hexyl-1-decyl, heptadecyl,
octadecyl (stearyl), isostearyl,
5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)octyl, nonadecyl, eicosyl,
docosyl, 2-octyl-1-dodecyl, triacontyl and tetracontyl. R.sup.1 and
R.sup.4 are preferably alkyl having 7 to 40 carbon atoms, more
preferably alkyl having 7 to 30 carbon atoms, further preferably
alkyl having 7 to 25 carbon atoms, and particularly preferably
alkyl having 7 to 20 carbon atoms.
[0014] Compounds (I) can be produced by known methods for synthesis
of esters. For example, Compound (I) can be obtained by reacting
the corresponding dibasic acid with 1 to 10 equivalents, preferably
1 to 2 equivalents of an aliphatic alcohol, if necessary, in the
presence of an entrainer and a catalytic amount to 0.5 equivalent
of an acid catalyst such as p-toluenesulfonic acid at 50 to
180.degree. C. Examples of the entrainers include toluene and
benzene. They are usually used in an amount of 0.5 to 100
equivalents on the basis of dibasic acid.
[0015] A dibasic acid used as a starting material can be produced
by treating the corresponding diol in the presence of 1 to 5
equivalents of a base such as sodium hydroxide or potassium
hydroxide, preferably at 200 to 320.degree. C. according to known
methods [Yukagaku (Oil Chenistry), Vol. 19, No. 12, p. 1087 (1970);
Japanese Published Unexamined Patent Application No. 72948/94;
etc.]. In this treatment, a reaction solvent such as an ether
solvent (e.g., dibenzyl ether) or a hydrocarbon solvent (e.g.,
liquid paraffin having 10 to 16 carbon atoms) may be used.
[0016] The lubricating base oil of the present invention preferably
contains Compound (I) in an amount of 10 wt % or more, more
preferably 25 wt % or more, further preferably. 50 wt % or more on
the basis of the total amount.
[0017] The lubricating base oil of the present invention may
contain additional base oils such as ester oils,
poly-.alpha.-olefin, mineral oils and silicone oils as may be
required.
[0018] Examples of the ester oils are fatty acid monoesters, adipic
acid diesters, azelaic acid diesters, sebacic acid diesters and
phthalic acid diesters.
[0019] Examples of the poly-.alpha.-olefin are low molecular weight
polybutene, low molecular weight polypropylene and .alpha.-olefin
oligomers having 8 to 14 carbon atoms.
[0020] Examples of the mineral oils are paraffin-base crude oil,
intermediate base crude oil and naphthene-base crude oil.
[0021] There is no specific restriction as to the amount of
additional base oils such as ester oils, poly-.alpha.-olefin,
mineral oils and silicone oils, but it is preferably 90 wt % or
less, more preferably 50 wt % or less on the basis of Compound
(I).
[0022] The lubricating oil of the present invention can be obtained
by adding to the lubricating base oil of the present invention,
according to need, additives such as a detergent-dispersant, an
antioxidant, an extreme-pressure additive, a rust inhibitor, a
vapor phase rust inhibitor, a pour point depressant, a thickener,
an antiseptic, an antifoaming agent, a demulsifier, an
extreme-pressure additive, a dye and a perfume. There is no
specific restriction as to the amount of these additives, but it is
preferably 0.01 to 5 wt % of the lubricating oil of the present
invention.
[0023] The lubricating base oil and the lubricating oil of the
present invention are excellent in hydrolysis resistance,
lubrication, heat resistance, low temperature fluidity, flame
resistance, biodegradability, or the like.
[0024] The lubricating oil of the present invention can be
employed, for example, as engine oil, turbine oil, hydraulic oil,
refrigerating oil, rolling oil, grease, lubricating oil for metal
processing, etc. according to known methods (WO97/21792, Japanese
Published Unexamined Patent Application No. 2001-89776, etc.).
TEST EXAMPLE 1
Hydrolysis Resistance Test
[0025] Hydrolysis resistance test was carried out using Compounds 1
and 2 respectively synthesized in Examples 1 and 2, and DOA
(dioctyl adipate) as a comparative compound. Test method: Into a
test solution comprising a test sample and water (weight ratio:
3:1) were put a copper piece and an iron piece as catalysts, and
the test solution was allowed to stand with stirring at 100.degree.
C. for 168 hours. The total acid number of the oil layer was
measured after standing (the total acid number becomes larger as
hydrolysis proceeds). The test results are shown in Table 1.
1 TABLE 1 Total acid value (mgKOH/g) Compound 1 0.12 Compound 2
0.03 Comparative compound 0.26
[0026] It is evident from Table 1 that Compounds 1 and 2 are
remarkably excellent in hydrolysis resistance, compared with the
comparative compound.
BEST MODES FOR CARRYING OUT THE INVENTION
[0027] Measurement data in the following reference example and
examples were obtained using the following measurement
instruments.
[0028] Mass spectrum (MS): M-80B mass spectrometer (Hitachi Co.,
Ltd.)
[0029] Infrared spectrum (IR): FTS-40A (Bio-Rad Japan)
[0030] Proton nuclear magnetic resonance spectrum (.sup.1H-NMR):
GSX-400 (400 MHz) (JEOL Ltd.)
[0031] Density: electronic densimeter SP-120L (Alfa Mirage Co.,
Ltd.)
[0032] Kinematic viscosity: Cannon-Fenske viscometer (measured
according to the method of JIS K2283)
Reference Example 1
[0033] 2,4-Diethyl-1,5-pentanediol (160.3 g) (trade name: Kyowadiol
PD-9, Kyowa Yuka Co., Ltd., purity: 93.9%), 156.6 g of potassium
hydroxide (purity: 86%) and 102.2 g of carbon number 12 paraffin
mixture (trade name: Kyowasol C1200-H, Kyowa Yuka Co., Ltd.) were
placed in a 1L nickel autoclave equipped with a reflux condenser, a
pressure control valve and an electric furnace capable of
temperature control, and heated with stirring under 1 MPa. The
generated hydrogen gas was measured with a gas meter, and the
progress of reaction was monitored. The generation of the gas was
confirmed at around 230.degree. C., and the reaction was continued
at a temperature maintained in the range of 250 to 270.degree. C.
After the temperature reached 250.degree. C., 89.4 l of hydrogen
was generated in 3.5 hours. The reaction was continued for further
30 minutes, during which 0.8 l of hydrogen gas was generated. The
amount of the generated hydrogen agreed with the theoretical value
and the rate of reaction was 100%. After the reaction, the reaction
mixture containing dipotassium 2,4-diethylglutarate was dissolved
in water, and sulfuric acid was added thereto. The deposited solid
was separated therefrom by filtration to obtain crude
2,4-diethylglutaric acid. The obtained crude 2,4-diethylglutaric
acid was washed with water and purified by crystallization from
n-hexane, whereby 142.5 g of 2,4-diethylglutaric acid (white
crystals) was obtained. The obtained 2,4-diethylglutaric acid had
98.3% purity (calculated from acid value) (yield: 79.1%).
Example 1
Synthesis of bis(2-ethylhexyl) 2,4-diethylglutarate (Compound
1)
[0034] In a reaction flask were placed 2,4-diethylglutaric acid
(92.50 g), 2-ethylhexanol (66.00 g) and toluene (157.3 g), and the
mixture was stirred well and p-toluenesulfonic acid monohydrate
(2.67 g) was added thereto, followed by reflux for 5 hours. After
cooling to room temperature, the reaction mixture was neutralized
with a 0.1 wt % aqueous solution of sodium hydroxide and then
washed with water. The solvent was distilled away from the reaction
mixture at 135.degree. C. in vacuo, whereby 146 g of Compound 1
(yield: 98.4%) was obtained. The physical properties of Compound 1
were as follows.
[0035] .sup.1H-NMR (CDCl.sub.3, .delta. ppm): 3.98 (m, 4H), 2.32
(m, 2H), 1.94 (m, 1H), 1.75 (m, 1H), 1.59 (m, 4H), 1.28 (m, 18H),
0.95 (m, 18H)
[0036] IR (cm.sup.-1): 2972, 2942, 2887 (C--H), 1745 (C.dbd.O),
1465, 1388, 1261, 1163 (C--O)
[0037] MS (m/z): 414 (M.sup.+)
[0038] Density (kg/m.sup.3): 929 (25.degree. C.)
[0039] Kinematic viscosity (cSt): 9.47 (40.degree. C.), 2.53
(100.degree. C.)
Example 2
Synthesis of
bis[5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)octyl]2,4-diethyl-
glutarate (Compound 2)
[0040] In a reaction flask were placed 2,4-diethylglutaric acid
(92.06 g), 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)octyl alcohol
(28.32 g) and toluene (30.23 g), and the mixture was stirred well
and p-toluenesulfonic acid monohydrate (1.13 g) was added thereto,
followed by reflux for 4 hours. After cooling to room temperature,
the reaction mixture was neutralized with a 0.2 wt % aqueous
solution of sodium hydroxide and then washed with water.
5,7,7-Trimethyl-2-(1,3,3-trimethylbutyl)octyl alcohol was removed
from the reaction mixture by extraction with methanol (three
times), whereby 82.9 g of Compound 2 (yield: 79.0%) was obtained.
The physical properties of Compound 2 were as follows.
[0041] .sup.1H-NMR (CDCl.sub.3, .delta. ppm): 4.01 (m, 4H), 2.32
(m, 2H), 1.96-1.04 (m, 28H), 0.88 (m, 54H)
[0042] IR (cm.sup.-1): 2962, 2916, 2887 (C--H), 1743 (C.dbd.O),
1471, 1384, 1233, 1197, 1164 (C--O)
[0043] Density (kg/m.sup.3): 879 (26.degree. C.)
[0044] Kinematic viscosity (cSt): 270 (40.degree. C.), 14.3
(100.degree. C.)
INDUSTRIAL APPLICABILITY
[0045] The present invention provides dibasic acid diesters, which
are suitable for use in lubricating base oils, etc. and excellent
in hydrolysis resistance, etc.
* * * * *