Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Heterocyclic ring compound; a heterocyclic ring is one...
Reexamination Certificate
2002-06-10
2004-05-11
McAvoy, Ellen M (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Heterocyclic ring compound; a heterocyclic ring is one...
C508S285000, C508S286000, C508S375000, C548S316400
Reexamination Certificate
active
06734149
ABSTRACT:
BACKGROUND
This invention relates generally to combinations of oil-soluble additives for lubricating oils.
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. Dithiohydantoin compounds are disclosed in European Patent Application No. EP 0 728 747 A1. However, the compounds are not within the scope of the present invention, and moreover, are disclosed only for pharmaceutical applications.
The problem addressed by this invention is to find improved oil-soluble additives for lubricating oils.
STATEMENT OF INVENTION
The present invention is directed to a composition comprising:
(a) from 1% to 99% of at least one compound of formula I:
wherein W represents O, S—A
2
, or two groups, R
3
and R
4
; bonds a and b are single or double bonds, provided that one of a and b is a single bond and the other is a double bond; c is a single or double bond, and d is a single bond, double bond, or two single bonds, provided that d is a single bond when c is a double bond, d is not a single bond when c is a single bond, and W is R
3
and R
4
when d is two single bonds;
A
1
, A
2
, B
1
and B
2
are independently hydrogen, alkyl, alkenyl, aralkyl or one of the groups depicted in Scheme 1:
provided that B
1
is absent when b is a double bond, B
2
is absent when a is a double bond, A
1
is absent when c is a double bond and A
2
is absent when d is a double bond; and provided that A
2
or B
2
is not aralkyl when W is O or S—A
2
;
R
1
, R
2
, R
3
and R
4
are independently hydrogen, alkyl, alkenyl, aryl or aralkyl; or R
1
and R
2
, or R
3
and R
4
, combine with the carbon atom to which they are attached to form an alkyl or alkenyl ring; Y is O or S; Z is O, S or NR
9
; m is 0 when bond e is a double bond and 1 when e is a single bond; n is 1 when bond f is a double bond and 2 when f is a single bond; R
5
is C(Y)ZR
7
, hydrogen or C
1
-C
4
alkyl; R
6
is hydrogen or C
1
-C
4
alkyl; R
7
, R
8
, R
9
, R
10
, R
11
and R
12
are independently hydrogen, alkyl, alkenyl, aryl or aralkyl;
provided that at least one of A
1
, A
2
, B
1
and B
2
is present and is not hydrogen; and
(b) from 1% to 99% of at least one dithiophosphate.
The present invention is further directed to a composition comprising a lubricating oil, from 0.05% to 15% of a compound of formula I, and from 0.01% to 10% of a dithiophosphate; and to a method for improving the anti-wear and anti-corrosion characteristics of a lubricating oil by adding from 0.05% to 15% of a compound of formula I, and from 0.01% to 10% of a dithiophosphate.
DETAILED DESCRIPTION
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 “alkanoyl” group is an alkyl group linked through a carbonyl group, e.g., an acetyl group. 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.
A “dithiophosphate” is any compound having a dithiophosphate group, preferably a dithiophosphate ester group {(RO)
2
P(S)S—, where the R groups are the same or different alkyl, aryl, aralkyl or alkenyl groups}, for example, a dialkyldithiophosphate group, a diaralkyldithiophosphate group, or a combination thereof. Examples of dialkyldithiophosphates include, but are not limited to, S-alkanoyl dialkyldithiophosphates, S-alkyl dialkyldithiophosphates and ZDDP. The term “ZDDP” refers to a zinc dialkyldithiophosphate having the structure
wherein R
A
, R
B
, R
C
and R
D
independently represent C
1
-C
22
alkyl groups. Preferably, alkyl groups are primary or secondary alkyl groups. Preferably, alkyl groups are C
2
-C
12
alkyl groups, more preferably C
2
-C
8
alkyl groups, and most preferably C
3
-C
6
alkyl groups.
In formula I and Scheme 1, the letter a, b, c, d, e or f represents the total bonding between the atoms adjacent to each letter, e.g., when “a” represents a single bond, the sulfur atom and ring carbon to which it is attached are connected by a single bond. These letters are used in formula I to indicate that the compound may exist in different tautomeric forms, e.g., when the sulfur shown in formula I is substituted, i.e., B
2
is present, a is a single bond, b is a double bond and B
1
is absent, as will be understood by one skilled in the art. In the substituent groups of Scheme 1, e and f indicate whether the bond between the adjacent carbons is a single or double bond, which is determined by the alkylating agent used to introduce the substituent, as described hereinbelow.
It is preferred that at least one of A
1
, A
2
, B
1
and B
2
is present and is not hydrogen or methyl. It is preferred that if the only one of A
1
, A
2
, B
1
and B
2
which is present, and is not hydrogen, is alkyl, then it is C
8
-C
22
alkyl, more preferably C
16
-C
22
alkyl, i.e., it is preferred that any alkyl group attached to nitrogen or sulfur is in one of the aforementioned ranges. It is also preferred that A
1
, A
2
, B
1
and B
2
are independently hydrogen or one of the three groups depicted in Scheme 1. It is also preferred that W is R
3
and R
4
, and c is a single bond. It is also preferred that W is R
3
and R
4
, c is a single bond, A
1
is hydrogen, and B
1
or B
2
is one of the groups depicted in Scheme 1.
Preferably, Y and Z are O, e is a single bond, m is one and R
5
and R
6
independently are hydrogen or methyl. Preferably, R
7
is alkyl. In one aspect of the invention, a tetraalkylimidazolidinethione (TAIT), or an imidazolidinethione having from one to three alkyl groups, is alkylated with an acrylate ester to produce a compound having a —CHR
5
CHR
6
C(O)OR
7
group, as shown below for an alkyl acrylate, resulting in R
5
═R
6
═H and R
7
═alkyl. Reaction with methacrylate or crotonate esters, resulting in R
6
═CH
3
or R
5
═CH
3
, respectively, also is possible. If R
1
, R
2
, R
3
and R
4
are all methyl, the TAIT is known as TMIT.
The extent of N-alkylation versus S-alkylation varies with the identity of the R groups on the imidazolidenethione ring and with the alkylating agent, as shown below in the Examples.
In another aspect of this invention, a TAIT or an imidazolidinethione having from one to three alkyl groups is alkylated with an alkyl propiolate to produce a compound in which the ester side chain has
Crimaldi Kenneth
McAvoy Ellen M
Rohm and Haas Company
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