Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic sulfur compound – wherein the sulfur is single bonded...
Reexamination Certificate
1998-11-20
2003-04-22
Toomer, Cephia D. (Department: 1714)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Organic sulfur compound, wherein the sulfur is single bonded...
C562S115000
Reexamination Certificate
active
06551967
ABSTRACT:
BACKGROUND OF THE INVENTION
Sulfonates, particularly calcium, barium or magnesium overbased sulfonates are widely used as additives for lubricating oils. The term “overbased” is used to describe sulfonates containing an amount of metal in excess of that required to react with the sulfonic acid from which the sulfonate is obtained. Frequently, the excess metal is in the form of its carbonate, in which case the overbased sulfonate consists of a colloidal dispersion of the metal carbonate in the metal sulfonate as dispersant. These overbased sulfonates are used as dispersants in the lubricating oil where their basicity neutralizes acids which develop in the crank cases of engines during engine operation, thus reducing corrosion.
Sulfonates are generally obtained from monoalkylates of aromatics, the alkyl chain being either branched or straight. Oil soluble sulfonates are obtained from alkylates containing an alkyl group of more than 16, generally more than 20, carbon atoms.
WO 96/26919 discloses low base number sulfonates which are said to be useful in lubricants. The sulfonates are prepared from high molecular weight sulfonic acids (i.e., they have a number average molecular weight of 500 or higher). The high molecular weight sulfonic acids may be alkaryl sulfonic acids, for example alkyl benzene sulfonic acid, alkyl toluene sulfonic acid or alkylxylene sulfonic acid. It is preferred that the sulfonic acid is a mixed sulfonic acid of C
15
to C
60
and higher alkyl benzene or C
15
to C
60
and higher alkyl xylene or C
15
to C
60
and higher alkyl toluene sulfonic acids.
A lower molecular weight sulfonic acid may also be used. It is preferably an alkylaryl sulfonic acid and most preferably a mixture of C
8
to C
30
and higher alkyl substituted alkyl benzene or alkyl toluene or alkyl xylene sulfonic acid. It is preferred that the lower molecular weight sulfonic acid has a number average molecular weight of at least 300, preferably at least 350.
The preferred high molecular weight sulfonic acids and when present lower molecular weight sulfonic acids are said to be those which are derived from aromatic alkylates prepared from C
2
, C
3
or C
4
polyolefins such as polyethylene, polypropylene or polynormal butene. It is also said to be possible to prepare straight chain lower molecular weight sulfonic acids from aromatic alkylates prepared from straight chain hydrocarbons such as linear alpha-olefins.
U.S. Pat. No. 4,235,810, issued Nov. 25, 1980 to Osselet et al., discloses alkyl aromatics prepared by alkylation with a mixture of straight and branched chain olefins containing 16 to 30 carbon atoms. Oligomers of propylene are said to be the preferred branched chain olefin. The alkyl aromatics can be converted to sulfonates having a Total Base Number of 300.
U.S. Pat. No. 4,259,193, issued Mar. 31, 1981 to Tirtiaux et al., discloses overbased alkaline earth metal mono-alkyl ortho-xylene in which the alkylaryl moiety is a mono-alkyl ortho-xylene or a mono-alkyl toluene and the alkyl group contains 15 to 40 carbon atoms. The alkyl group may be straight chain or branched. Oligomers of propylene may be used for the alkyl group. In the examples, the overbased sulfonates have a Total Base Number of 300.
U.S. Pat. No. 4,387,033, issued Jun. 7, 1983 to Lenack et al., discloses highly basic calcium sulfonates having a Total Base Number of 400. The alkyl sulfonic acid used to prepared the sulfonate should preferably have at least 18 carbon atoms in the alkyl chain. Alkaryl sulfonic acids having a molecular weight of between 300 and 700, e.g., between 400 and 500, such as alkyl benzene and alkyl toluene sulfonic acids are said to be suitable. The alkyl group may be straight chain or branched.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a low overbased alkaline earth metal alkylaryl sulfonate having a Total Base Number of from about 2 to about 30, a dialkylate content of 0% to about 25% and a monoalkylate content of about 75% to about 90% or more, wherein the alkylaryl moiety is alkyltoluene or alkylbenzene in which the alkyl group is a C
15
-C
21
branched chain alkyl group derived from a propylene oligomer.
The present invention also provides a lubricating oil containing a low overbased alkaline earth metal alkylaryl sulfonate having a Total Base Number of from about 2 to about 30, a dialkylate content of 0% to about 25% and a monoalkylate content of about 75% to about 90% or more, wherein the alkylaryl moiety is alkyltoluene or alkylbenzene in which the alkyl group is a C
15
-C
21
branched chain alkyl group derived from a propylene oligomer.
Also provided by the present invention is a lubricating oil formulation comprising:
(a) a major amount of a base oil of lubricating viscosity;
(b) about from 1 to 20 weight % of at least one ashless dispersant;
(c) from 1 to 40 weight % of a low overbased alkaline earth metal alkylaryl sulfonate having a Total Base Number of from about 2 to about 30, a dialkylate content of 0% to about 25% and a monoalkylate content of about 75% to about 100%, wherein the alkylaryl moiety is alkyltoluene or alkylbenzene in which the alkyl group is a C
15
-C
21
branched chain alkyl group derived from a propylene oligomer;
(d) about from 0.05 to 5 weight % of at least one zinc dithiophosphate;
(e) from 0 to 10 weight % of at least one oxidation inhibitor;
(f) from 0 to 1 weight % of at least one foam inhibitor; and
(g) from 0 to 20 weight % of at least one viscosity index improver.
The present invention further provides a concentrate comprising about from 10 weight % to 90 weight % of a compatible organic liquid diluent and about from 0.5 weight % to 90 weight % of a low overbased alkaline earth metal alkylaryl sulfonate having a Total Base Number of from about 2 to about 30, a dialkylate content of 0% to about 25% and a monoalkylate content of about 75% to about 100%, wherein the alkylaryl moiety is alkyltoluene or alkylbenzene in which the alkyl group is a C
15
-C
21
branched chain alkyl group derived from a propylene oligomer.
Further provided in accordance with the present invention is a method of producing a lubricating oil composition comprising blending the following components together:
(a) a major amount of a base oil of lubricating viscosity;
(b) from 1 to 20 weight % of at least one ashless dispersant;
(c) from 5 to 20 weight % of a low overbased alkaline earth metal alkylaryl sulfonate having a Total Base Number of from about 2 to about 30, a dialkylate content of 0% to about 25% and a monoalkylate content of about 75% to about 100%, wherein the alkylaryl moiety is alkyltoluene or alkylbenzene in which the alkyl group is a C
15
-C
21
branched chain alkyl group derived from a propylene oligomer;
(d) from 0.05 to 5 weight % of at least one zinc dithiophosphate;
(e) from 0 to 10 weight % of at least one oxidation inhibitor;
(f) from 0 to 1 weight % of at least one foam inhibitor; and
(g) from 0 to 20 weight % of at least one viscosity index improver.
The present invention also provides the lubricating oil composition produced by this method.
The present invention also provides an improved method of preparing an alkaline earth metal alkyltoluene sulfonate by reacting an alkyltoluene sulfonic acid with an active source of alkaline earth metal in the presence of a solvent, wherein the improvement comprises using water as the solvent.
DETAILED DESCRIPTION OF THE INVENTION
The low overbased alkylaryl sulfonates of the present invention are prepared from alkylates of benzene and toluene. The alkylates may be prepared by Friedel-Crafts alkylation of the benzene or toluene using techniques known in the art.
The alkylates used to prepare the sulfonates of this invention are prepared using a propylene oligomer for the alkyl group. The propylene oligomers useful for this purpose have an average of about 15 to 21, preferably about 14 to 18, carbon atoms. The oligomers have a low di-olefin content, i.e., they have a Bromine Number of about 15 to about 25 mg/100 g.
The synthesis of the alkyltoluene alkylate can be accomplished by t
Campbell Curtis Bay
Clement Olivier
Coent Jean-Louis Le
King William Frank
Lockett Steven Gale
Chevron Chemical S.A.
Kelley Sarita R.
Sheridan Richard J.
Toomer Cephia D.
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