LUBRICATING OIL COMPOSITIONS CONTAINING HYDROXYAMIDE COMPOUNDS AS FRICTION REDUCERS

HUILES LUBRIFIANTES RENFERMANT DES HYDROXYAMIDES COMME AGENTS ANTI-FROTTEMENT

English Abstract

ABSTRACT OF THE DISCLOSURE
A lubricating oil composition having im-
proved friction reducing properties and the method of
reducing friction in internal combustion engines by
lubricating said engines with said lubricating oil
which contains an effective friction reducing amount
of a selected hydroxyamide compound.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A lubricating oil composition having improved friction
reducing properties comprising a major amount of lubricating base
oil and from about 0.01 to about 2.0 percent by weight of a
hydroxyamide compound having the formula:
<IMG>
where R is the hydrocarbon radical of dimer carboxylic acid having
a total of about 24 to about 90 carbon atoms with about 9 to about
42 carbon atoms between carboxylic acid groups and Z is (a) a
hydroxy substituted alkyl group having about 1 to about 20 carbon
atoms or (b) an oxyalkylene group of the formula:
<IMG>
where A and B are each alkyl of 1 to 2 carbon atoms or hydrogen
and m is an integer of 1 to 50; x is 0 or 1: y is 1 or 2 and n is
2.
2. The composition of claim 1 wherein said dimer acid has a
total of about 24 to about 60 carbon atoms and about 12 to about
42 carbon atoms between the carboxylic acid groups and said
hydroxy substituted alkyl group has about 1 to about 4 hydroxy
groups.
11

3. The composition of claim 2 wherein said hydroxy
substituted alkyl group has about 1 to about 10 carbon atoms.
4 The composition of claim 3 wherein in said oxyalkylene
group, A and/or B are hydrogen, and m is 1 to 40.
5. The composition of claim 4 wherein about 0.01 to about 1.0
percent by weight of said hydroxyamide compound is used.
6. The composition of claim 5 wherein said dimer acid has a
total of about 24 to about 44 carbon atoms and about 16 to about
22 carbon atoms between the carboxylic acid groups and said Z
group in said hydroxyamide compound is a hydroxy substituted alkyl
group.
7. The composition of claim 6 wherein said hydroxy
substituted alkyl group has 1 to 2 hydroxy groups and 2 to 6
carbon atoms.
8. The composition of claim 7 wherein from about 0.05 to
about 0.5 weight percent of said hydroxyamide compound is used.
9. The composition of claim 8 wherein the hydroxyamide
compound is prepared from the combination of a dimer acid selected
from the group consisting of linoleic acid, oleic acid and
mixtures thereof, and a hydroxyamine compound selected from the
group consisting of ethanolamine and diethanolamine.
10. A method of reducing friction in an internal combustion
engine comprising lubricating said engine using a lubricating oil
composition containing an effective friction reducing amount of an
additive which is hydroxyamide compound having the formula:
12

<IMG>
where R is the hydrocarbon radical of dimer carboxylic acid having
a total of about 24 to about 90 carbon atoms with about 9 to about
42 carbon atoms between carboxylic acid groups, Z is (a) a hydroxy
substituted alkyl group having about 1 to about 20 carbon atoms,
or (b) an oxyalkylene group of the formula:
<IMG>
where A and B are each alkyl of 1 to 2 carbon atoms or hydrogen
and m is an integer of 1 to 50: x is 0 or 1, y is 1 or 2, and n is
2.
11. The method of claim 10 wherein said composition contains
about 0.01 to about 2.0 percent by weight of said hydroxyamide
compound.
12. The method of claim 11 wherein said dimer acid has a
total of about 24 to about 60 carbon atoms and about 12 to about
42 carbon atoms between the carboxylic acid groups and said
substituted hydroxyalkyl group has about 1 to about 4 hydroxy
groups.
13

13. The method of claim 12 wherein said hydroxy substituted
alkyl group has about 1 to about 10 carbon atoms and said
composition contains about 0.01 to about 1.0 percent by weight of
said hydroxyamide compound.
14. The method of claim 13 wherein said oxyalkylene group, A
and/or B are hydrogen, and m is 1 to 40.
15. The method of claim 14 wherein said dimer acid has a
total of about 24 to about 44 carbon atoms and about 16 to about
22 carbon atoms between the carboxylic acid qroups and said Z
group in said hydroxyamide compound is a hydroxy substituted alkyl
group.
16. The method of claim 15 wherein said hydroxy substituted
alkyl group has 1 to 2 hydroxy groups and 2 to 6 carbon atoms.
17. The method of claim 16 wherein said composition contains
about 0.05 to about 0.5 weight percent of said hydroxyamide
compound.
14

Description

BACKGROUND OF THE INVENTION
This invention relates to a lubricating oil
composition having improved friction reducing proper-
ties and to a method for reducing friction in internal
combustion enginesO More particularly, this invention
is directed to a lubricating oil composition contain
ing selected hydroxyamide compounds as friction reduc-
ing additives and to a method of reducing friction in
an internal combustion engine by using a lubricating
oil which contains said hydroxyamide compounds.
There has been considerable efEort in
recent years to improve the fuel economy of automotive
engines which operate on petroleum fuel, a product
which like other forms of energy has become relatively
expensive. Some of the known ways to improve fuel
economy have been of a mechanical or design nature,
such as building smaller cars and engines. Since it
is known that high engine friction causes significant
energy l~ss, another way to improve fuel economy of
automotive engines is to reduce such friction.
~ ajor efforts to reduce friction in auto-
motive engines have involved the lubricating oils used
in such engines. One approach has been to use syn-
thetic ester base oils which are generally expensive.
Another approach has been to use additives to improve
the friction properties of the lubricating oil. Among
the friction reducing additives which have been used
are a number of molybdenum compounds including insol-
uble molybdenum sulfides and several organo molybdenum
complexes, e.g. molybdenum amine complexes disclosed
in U. S. Patent 4,164,473, molybdenum thio-bis-phenol
,,,,~

S3~
-- 2
complexes disclosed in U. S. Patents 4,192,753,
4,201,683, and 4,248,720, molybdenum oxazoline com-
plexes disclosed in U. S. Patent 4,176,074 and molyb-
denum lactone oxazoline complexes disclosed in U. S.
Patent 4,176,073.
Another group of friction reducing addi-
tives which have been used in lubricating oils are the
carboxylic acid esters. These compounds include the
esters of fatty acid dimers and glycols as disclosed
in U. S. Patent 4,105,571, the esters of monocar-
boxylic acids and glycerol as disclosed in U. S.
4,304,678, the ester of dimer acids and~monohydric
alcohol disclosed in U. S. 4,167,486, the esters oE
glycerol and monocarboxylic fatty acids as disclosed
in U.K. 2,038,355 and 2,038,356, and esters o~ mono-
carboxylic fatty acids and polyhydric alcohols dis-
closed in U. S~ 3,933,659.
Other friction reducing additives employed
in lubricating compositions include nitrogen-contain-
ing products of phosphosulfurized esters disclosed in
U. S. Patent 4,298,484 and boric acid salts or borate
esters of hydroxyalkyl imidazolines shown in U. S.
Patent 4,298,486.
While the different approaches and addi-
tives all generally provide some reduced engine fric-
tion and consequently improved fuel economy, there is
still the need for additional additives and composi-
tions which provide the necessary and desired friction
reduction, and are also economical, readily avail-
able, and most important, are compatible with commonly
used lubricating base oils and the many conventional
additives used in lubricating oil compositions.

3~
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SUMMARY OF THE INVENTION
-
Now it has been found that lubricating oil
compositions containing selected hydroxyamine com-
pounds as an additive have improved friction reducing
properties.
More particularly, this invention is di-
rected to a lubricating oil composition haviny im-
proved friction reducing properties comprising a major
amount of lubricating base oil and from about On Ql to
about.2.0 percent by weight of a hydroxyamide compound
having the formula:
R ~ CN(H)x(Z)y~
where R is the hydrocarbon radical or skeleton of a
dimer carboxylic acid having a total of about 24 to
about 9O carbon atoms with about 9 to about 42 carbon
atoms between carboxylic acid groups; Z is a) a
hydroxy substituted alkyl group having about 1 to
about 20 carbon atoms or b) an oxyalkylene group of
the formula:
A B
(CH - CHO~ H
m
where A and B are each alkyl of 1 to 2 carbon atoms
and m is an integer of 1 to 50;
x is 0 or 1; y is 1 or 2 and n is 1 or 2.

~2~53~
-- 4 --
Another embodiment of this invention
relates to a method of reducing friction in an inter-
nal combustion engine by lubricating said engine using
a lubricating oil composition which contains an effec-
tive friction reducing amount of the selected hydroxy-
amide compound as described herein.
DETAILED DESCRIPTION OF THE INVENTION
This invention is directed to a lubricating
oil composition containing a selected hydroxyamide
compound additive to provide improved friction reduc-
ing proper-ties and to a method of reducing friction in
an internal combustion engine by using a lubricating
oil composition which contains said selected hydroxy-
amide compound additive.
The friction reducing additive which is
used in this invention is an oil soluble hydroxyamide
compound having the formula:
Rl CN(H)X(z)y~ (I)
where R is the hydrocarbon radical, backbone or
skeleton of a dimer carboxylic acid, Z is a hydroxy
substituted alkyl group or an oxyalkylene group, and
x, y and n are integers as hereinafter defined.
The dimer carboxylic acid used in preparing
the hydroxyamide compound of this invention will be a
dimer of an aliphatic saturated or unsaturated car-
boxylic acid, said dimer acid having a total of about
24 to about 90 carbon atoms, and from about 9 to about
42 carbon atoms between the carboxylic acid groups.
Preferably, the dimer acid will have a total of about
24 to about 60 carbon atoms and abou-t 12 to about 42

3~
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carbon atoms between the carboxylic acid groups, and
more preferably, a total of about 24 to about 44
carbon atoms and about 16 to a~bout 22 carbon atoms
between the carboxylic acid groups. The dimer acid
hydrocarbon residue or skeleton group as shown in the
hydroxyamide compound (I) may have one free carboxyl
group, i.e., it may not be completely amidated.
The Z qroup as found in the hydroxyamide
compound (I) may be a) a hydroxy substituted alkyl
group having about 1 to about 20, preferably 1 to 10,
and more preferably 2 to 6 carbon atoms; or 'D) an
oxyalkylene group of the formula:
A IB
(CH - CHO) - H
m
where A and B are each alkyl groups of 1 to 2 carbon
atoms and m is an integer oE 1 to 50. Preferably, in
the oxyalkylene group A and/or B will be hydrogen and
m will be 1 to 40. The preferred Z group in the
hydroxyamide compound (I) is the hydroxy substituted
alkyl group. In said hydroxy substituted alkyl group
there may be more than one hydroxy group and more
particularly 1 to 4 hydroxy groups with 1 to 2 being
preferred and more preferably 1 hydroxy group being
present~
In the hydroxyamide compound (I) shown
above, x, y, and n are integers with x beiny 0 or 1, y
being 1 or 2 and n being 1 or 2. Preferably x is 0, y
is 2, and n is 2.
The hydroxyamide compounds of this inven-
tion are generally obtained by condensing a hydroxy-
amine such as an alkanolamine with an acid at ele-

6S;3~
-- 6 --
vated temperature. They also may be obtained by thereaction of the dimer acid amide with an oxyalkylene
compound. Further description of the preparation of
the hydroxyamides may be found in Kirk-Othmer,"Ency-
clopedia of Chemical Technology," Second Edition, Vol.
2, 1963, pp. 66-76.
The dimer carboxylic acids used in prepar-
ing the hydroxyamides of this invention and described
of above are well known, commercially available com-
pounds. Further details about such compounds may be
found in U. S. Patents 3,189,832; 3,429,817;
3,223,635; 4,105,571 and 4,388,201. In referring to
dimer acids in this application, it is to be appre-
ciated that reactions for producing such acids, par-
ticularly in commercia] operations will generally lead
to trimer and even tetramer Eormation and in some
cases the product obtained will conkain mlnor amounks
of unreacted monomer or monomers. ~s a result, com-
mercially available dimer acids may contain other
products including as much as 25~ trimer. The use of
mixtures is within the scope of the present invention
and intended to be covered by the term " dimer acid"
as used herein.
The hydroxyamine compounds used in prepar-
ing the hydroxyamides of this invention are also known
and commercially available and generally are named as
alkanolamines or aminoalcohols. The hydroxyalkyl
amines as described above can be considered deriva-
tives of ammonia where at least one hydrogen is re-
placed by a hydroxyalkyl radical. One commercial
method oE preparation involves the reaction of ethyl-
ene oxide or propylene oxide with ammonia. The oxy-
alkylated amines may be formed as above, but also the

;53~
-- 7 --
oxyalkylated amines may be formed more directly from
the reaction of a dimer acid amide, i.e., DA-CONH2
where DA is the dimer acid backbone, with an oxyal-
kylene compound such as ethylene or propylene oxide.
Further description of the preparation of the hydroxy-
amine compounds of the type used in this invention may
be found in Kirk-Othmer, "Encyclopedia of Chemical
Technology," Second Edition, Vol. 1, 1963, pp. 809-831
and Vol. 2, 1963, pp~ 72-73. Typical compounds of this
type include ethanolamine, diethanolamine, propanol-
amine, and 3-amino-1, l-propanediol.
In preparing the hydroxyamide compounds
used in this invention, yenerally one or more moles of
hydroxyamine per mole of dimer acid is used depending
on the degree of amidation of the dimer carboxyl
groups that is desired. More particularly, from about
1:1 to about 3:}: moles of hydroxyamine per mole oE
dimer acid is used with about l:l to about 2:1 being
preferred.
The hydroxamide friction reducing additives
of this invention will generally be used at a concen-
tration of from about 0.01 to about 2.0 percent by
weight, preferably from about 0.01 to about 1.0 and
more preferably from about 0.05 to about 0.5 percent
by weight based on the total weight of the lubricating
oil composition.
The lubricating base oil will generally
comprise a major amount of the lubricating composi-
tion, i.e., at least 50% by weight thereof, and will
include liquid hydrocarbons such as the mineral lubri-
cating oils and the synthetic lubricating oils and
mixtures thereof. The synthetic oils which can be

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used include diester oils such as di(2-ethylhexyl)
sebacate, azelate and adipate; complex ester oils such
as those formed Erom dicarboxylic acids, glycols and
either monobasic acids or monohydric alcohols;
silicone oils; sulfide esters; organic carbonates; and
other synthetic oils known to the art. Mineral oils
are the preferred lubricating base.
Other additives, known in the art, may be
added to the oil composition of the present invention
to form a finished oil. Such additives include dis-
persants, anti-wear agents, antioxidants, corrosion
inhibitors, detergents, pour point depressants,
extreme pressure additives, viscosity index improvers,
etc. These additives are typically disclosed for
example in "Lubricant Additives" by C. V. Snmalheer
and R. Kennedy Smith,~1967, pp. 1-11 and in U. S.
Patent 4,105,571.
The following examples are further illus-
trative of this invention and are not intended to be
construed as limitations thereof.
Example 1
A 10W40SE quality automotive engine oil was
prepared containing a base oil comprising about 56
parts by weight of solvent 150 neutral and about 19
parts by weight of solvent 100 neutral mineral oil.
It also contained 0.1 weight percent of a hydroxyamide
compound friction reducing additive prepared by react-
ing a dimer acid comprising linoleic and/or oleic acid
(sold commercially by Emery Industries, Inc., as Empol
1010) and ethanolamine. The composition additionally
contained other additives conventionally used in auto-

s~
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motlve engine oils including a zinc dialkyl dithio-
phosphate antioxidant/antiwear agent, a rust inhibi-
tor, i.e., overbased magnesium sulfonate, a detergent,
and a V.I. improver, i.e., an ethylene-propylene
copolymer.
The prepared composition was tested for
coefficient of friction using a ball on cylinder test
described in the "Journal of the American Society of
Lubrication Engineers" (ASLE Transaction), Vol. 4~
pages 1-11, 1961. In essence, the apparatus consists
basically of a fixed metal ball loaded against a
rotating cylinder. The weight on the ball and the
rotation of the cylinder can be varied during any
given test or from test to test. Also, the time of any
given test can be varied. Generally, however, steel
on steel is used at a constant load, constant rpm and
a fixed time and in each test oE these examples, a ~
kg load, 0.26 rpm and 70 minutes was used. The appa-
ratus and method used is more fully described in U. S.
Patent 3,129,580.
The prepared composition containing the
hydroxyamide additive gave a coefficient of friction
of 0.10. The same formulation without the additive
had a significantly higher friction of 0.28.
Example 2
Another automotive engine oil the same as
described in Example 1 but having a different friction
reducin~ additive, i.e., 0.1 weight percent of a
hydroxyamide prepared by reacting a dimer acid (as in
Example 1) with diethanolamine, was tested for co-
efficient of friction as in Example 1.

3~
- 10 ~
The resulting coefficient of friction was
0.11. As in t}-e previous example, this composition
containing the select hydroxyamide friction reducing
additive in accordance with this invention, showed
significantly reduced coefficient of friction as com-
pared to the same formulation without the additive.