U.S. patent application number 10/636111 was filed with the patent office on 2004-02-12 for cyclic thioureas as additives for lubricating oils.
Invention is credited to Mukkamala, Ravindranath.
Application Number | 20040029743 10/636111 |
Document ID | / |
Family ID | 31495972 |
Filed Date | 2004-02-12 |
United States Patent
Application |
20040029743 |
Kind Code |
A1 |
Mukkamala, Ravindranath |
February 12, 2004 |
Cyclic thioureas as additives for lubricating oils
Abstract
A composition comprising: (a) from 0.1% to 20% of at least one
cyclic thiourea compound of formula I: 1 wherein W is O or S;
R.sup.1 and R.sup.2 independently are hydrogen, alkyl, alkenyl,
aryl or aralkyl; R.sup.3 and R.sup.4 independently are hydrogen,
alkyl, alkenyl, aryl or aralkyl, or R.sup.3 and R.sup.4 groups
combine with ring carbon atoms to which they are attached to form a
five- to seven-membered heterocyclic ring; and (b) a lubricating
oil.
Inventors: |
Mukkamala, Ravindranath;
(Lansdale, PA) |
Correspondence
Address: |
ROHM AND HAAS COMPANY
PATENT DEPARTMENT
100 INDEPENDENCE MALL WEST
PHILADELPHIA
PA
19106-2399
US
|
Family ID: |
31495972 |
Appl. No.: |
10/636111 |
Filed: |
August 7, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60401540 |
Aug 7, 2002 |
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Current U.S.
Class: |
508/256 |
Current CPC
Class: |
C10M 2219/102 20130101;
C10M 2205/163 20130101; C10M 2205/143 20130101; C10M 2219/09
20130101; C10M 2207/1253 20130101; C10N 2030/10 20130101; C10M
105/24 20130101; C10N 2050/023 20200501; C10M 135/36 20130101; C10M
107/04 20130101; C10N 2010/04 20130101; C10N 2030/06 20130101; C10M
135/16 20130101; C10N 2030/12 20130101 |
Class at
Publication: |
508/256 |
International
Class: |
C10M 135/16 |
Claims
1. A composition comprising: (a) from 0.1% to 20% of at least one
cyclic thiourea compound of formula I: 8wherein W is O or S;
R.sup.1 and R.sup.2 independently are hydrogen, alkyl, alkenyl,
aryl or aralkyl; R.sup.3 and R.sup.4 independently are hydrogen,
alkyl, alkenyl, aryl or aralkyl, or R.sup.3 and R.sup.4 groups
combine with ring carbon atoms to which they are attached to form a
five- to seven-membered heterocyclic ring; and (b) a lubricating
oil.
2. The composition of claim 1 in which W is O, and R.sup.1,
R.sup.2, R.sup.3 and R.sup.4 independently are hydrogen, alkyl,
alkenyl, aryl or aralkyl.
3. The composition of claim 2 in which R.sup.1, R.sup.2, R.sup.3
and R.sup.4 independently are hydrogen or alkyl.
4. The composition of claim 3 in which at least one of R.sup.1,
R.sup.2, R.sup.3 and R.sup.4 is C.sub.6-C.sub.22 alkyl.
5. The composition of claim 1 in which W is S, and R.sup.1,
R.sup.2, R.sup.3 and R.sup.4 independently are hydrogen, alkyl,
alkenyl, aryl or aralkyl.
6. The composition of claim 1 in which R.sup.3 and R.sup.4 groups
combine with ring carbon atoms to which they are attached to form a
five- to seven-membered heterocyclic ring.
7. The composition of claim 6 in which the cyclic thiourea has
formula 9wherein R.sup.5 and R.sup.6 independently are hydrogen,
alkyl, alkenyl, aryl or aralkyl.
8. The composition of claim 7 in which W is O, R.sup.1 and R.sup.6
are the same, and R.sup.2 and R.sup.5 are the same.
9. The composition of claim 8 in which R.sup.1 and R.sup.2
independently are hydrogen or alkyl.
10. The composition of claim 9 in which at least one of R.sup.1 and
R.sup.2 is C.sub.6-C.sub.22 alkyl.
Description
BACKGROUND
[0001] This invention relates generally to cyclic thioureas useful
as additives for lubricating oils.
[0002] Zinc dialkyldithiophosphates (ZDDP) are widely used as
lubricant additives. The principal disadvantages of these compounds
are that an ash residue is produced by the zinc as the additive is
consumed, and that phosphorus is known to affect the efficiency of
catalytic converters in motor vehicles, thereby causing emissions
problems. Cyclic thiourea compounds useful as lubricant additives
are disclosed in U.S. Pat. No. 5,935,913. However, the compounds
disclosed therein are not within the scope of the present
invention.
[0003] The problem addressed by this invention is to find
additional non-metallic, non-phosphorus-containing oil-soluble
additives for lubricating oils.
STATEMENT OF INVENTION
[0004] The present invention is directed to a composition
comprising:
[0005] (a) from 0.1% to 20% of at least one cyclic thiourea
compound of formula I: 2
[0006] wherein W is O or S; R.sup.1 and R.sup.2 independently are
hydrogen, alkyl, alkenyl, aryl or aralkyl; R.sup.3 and R.sup.4
independently are hydrogen, alkyl, alkenyl, aryl or aralkyl, or
R.sup.3 and R.sup.4 groups combine with ring carbon atoms to which
they are attached to form a five- to seven-membered heterocyclic
ring; and
[0007] (b) a lubricating oil.
[0008] The present invention is further directed to a method for
improving the anti-wear characteristics of a lubricating oil by
adding from 0.1% to 20% of a compound of formula I.
DETAILED DESCRIPTION
[0009] All percentages are weight percentages based on the entire
composition described, unless specified otherwise. An "alkyl" group
is a saturated hydrocarbyl group having from one to twenty-two
carbon atoms in a linear, branched or cyclic arrangement, and
having from 0 to 2 oxygen, nitrogen or sulfur atoms. Substitution
on alkyl groups of one or more halo, hydroxy, alkoxy, alkanoyl or
amido groups is permitted; alkoxy, alkanoyl and amido groups may in
turn be substituted by one or more halo substituents. In one
preferred embodiment, alkyl groups contain from one to twelve
carbon atoms and from 0 to 1 oxygen, nitrogen or sulfur atoms; in
another preferred embodiment, alkyl groups contain from 12 to 22
carbon atoms, and more preferably, no heteroatoms. An "alkenyl"
group is an "alkyl" group in which at least one single bond has
been replaced with a double bond. An "aryl" group is a substituent
derived from an aromatic compound, including heterocyclic aromatic
compounds having heteroatoms chosen from among nitrogen, oxygen and
sulfur. An aryl group has a total of from five to twenty ring
atoms, and has one or more rings which are separate or fused.
Substitution on aryl groups of one or more halo, alkyl, alkenyl,
hydroxy, alkoxy, alkanoyl or amido groups is permitted, with
substitution by one or more halo groups being possible on alkyl,
alkenyl, alkoxy, alkanoyl or amido groups. An "aralkyl" group is an
"alkyl" group substituted by an "aryl" group. A "lubricating oil"
is a natural or synthetic oil, or a mixture thereof, having
suitable viscosity for use as a lubricant, e.g., as crankcase oil
in an internal combustion engine, automatic transmission fluid,
turbine lubricant, gear lubricant, compressor lubricant,
metal-working lubricant, hydraulic fluid, etc.
[0010] In one embodiment of the invention, preferably formula (I)
has R.sup.1, R.sup.2, R.sup.3 and R.sup.4 which independently are
hydrogen, alkyl, alkenyl, aryl or aralkyl, i.e., the compound is
not bicyclic. Preferably, R.sup.1, R.sup.2, R.sup.3 and R.sup.4
independently are hydrogen, alkyl or alkenyl, more preferably at
least one of R.sup.1, R.sup.2, R.sup.3 and R.sup.4 is
C.sub.6-C.sub.22 alkyl or alkenyl, more preferably at least one of
R.sup.1, R.sup.2, R.sup.3 and R.sup.4 is C.sub.10-C.sub.22 alkyl,
and most preferably at least one of R.sup.1, R.sup.2, R.sup.3 and
R.sup.4 is C.sub.16-C.sub.22 alkyl.
[0011] In another embodiment of the invention R.sup.3 and R.sup.4
groups in formula I combine with ring carbon atoms to which they
are attached to form a five- to seven-membered heterocyclic ring.
In a preferred embodiment R.sup.3 and R.sup.4 groups combine to
form the following bicyclic system of formula (II): 3
[0012] wherein R.sup.5 and R.sup.6 independently are hydrogen,
alkyl, alkenyl, aryl or aralkyl. In a preferred embodiment of the
invention, in which W is O, R.sup.1 and R.sup.6 are the same, and
R.sup.2 and R.sup.5 are the same, the compound is a symmetric
bicyclic compound of formula (III): 4
[0013] In one embodiment of the invention, a compound of formula
(I) is prepared from a 2-amino alkyl nitrile and carbon disulfide,
as shown below: 5
[0014] Preferably, R.sup.2 is C.sub.6-C.sub.22 alkyl or alkenyl,
more preferably C.sub.10-C.sub.22 alkyl, and most preferably
C.sub.16-C.sub.22 alkyl. Preferably, R.sup.2 is derived from an
unsubstituted C.sub.16-C.sub.22 alkyl amine, R.sup.2NH.sub.2,
preferably one which is an oil-soluble amine. In one preferred
embodiment, the alkyl amine is a tertiary alkyl primary amine.,
i.e., a primary amine in which the alkyl group is attached to the
amino group through a tertiary carbon. Examples of commercially
available tertiary alkyl primary amines are the Primene.TM. amines
available from Rohm and Haas Company, Philadelphia, Pa.
[0015] In one embodiment of the invention, a compound of formula
(III) is prepared from a substituted thiourea and a di-ester of
acetylenedicarboxylic acid, as shown below: 6
[0016] The R groups are alkyl, alkenyl, or aralkyl groups,
preferably C.sub.1-C.sub.4 alkyl groups. Preferably, R.sup.1 and
R.sup.2 are hydrogen, alkyl or alkenyl, more preferably at least
one of R.sup.1 and R.sup.2 is C.sub.6-C.sub.22 alkyl or alkenyl,
more preferably at least one of R.sup.1 and R.sup.2 is
C.sub.10-C.sub.22 alkyl, and most preferably at least one of
R.sup.1 and R.sup.2 is C.sub.16-C.sub.22 alkyl.
[0017] In one embodiment of the invention, a compound of formula
(I) is prepared from a substituted thiourea and an ester of a
.alpha.,.beta.-unsaturated carboxylic acid, as shown below: 7
[0018] Preferably, R.sup.3 and R.sup.4 are hydrogen or
C.sub.1-C.sub.4 alkyl. Preferably, R.sup.1 and R.sup.2 are
hydrogen, alkyl or alkenyl, more preferably at least one of R.sup.1
and R.sup.2 is C.sub.6-C.sub.22 alkyl or alkenyl, more preferably
at least one of R.sup.1 and R.sup.2 is C.sub.10-C.sub.22 alkyl, and
most preferably at least one of R.sup.1 and R.sup.2 is
C.sub.16-C.sub.22 alkyl.
[0019] Preferably, the compound(s) of formula (I) is present in a
lubricating oil in a total amount of at least 0.2%, more preferably
at least 0.3%, and most preferably at least 0.4%. Preferably, the
compound(s) of formula (I) is present in a lubricating oil in a
total amount no greater than 10%, more preferably no greater than
5%, and most preferably no greater than 2%. Preferably, the
compounds are soluble at the aforementioned levels.
[0020] Optionally, other additives typically used in lubricating
oils are present in the composition. Such additives include, but
are not limited to, other anti-wear additives, anti-corrosion
additives, dispersants, detergents, antioxidants, antifoamants,
friction modifiers, seal swell agents, demulsifiers, viscosity
index improvers and pour point depressants. Other anti-wear
additives that can be used in combination with the compound of
formula (I) include the commercial products known as ZDDP, which
are zinc dialkyldithiophosphates. In addition to improving the
anti-wear characteristics of lubricating oils, the compound of
formula (I) typically also improves anti-corrosion characteristics
and functions as an anti-oxidant.
* * * * *