Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic sulfur compound
Reexamination Certificate
1999-05-05
2001-07-31
Medley, Margaret (Department: 1714)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Organic sulfur compound
C508S585000, C508S586000, C568S075000
Reexamination Certificate
active
06268320
ABSTRACT:
TECHNICAL FIELD
This invention relates to sulphur-containing calixarenes, and to metal salts of such calixarenes, especially overbased metal salts. The invention also relates to the preparation of such overbased salts as well as their use in additive compositions and finished lubricating oil compositions.
BACKGROUND OF THE INVENTION
In the operation of internal combustion engines, by-products from the combustion chamber often blow by the piston and admix with the lubricating oil. Compounds generally employed to neutralize the acidic materials and disperse sludge within the lubricating oil are overbased, alkaline earth metal, sulphurised, hydrocarbyl-substituted phenates, salicylates, napthenates and sulphonates. The term “overbased” is generally used to describe metal salts in which the ratio of the number of equivalents of the metal moiety to the number of equivalents of the acid moiety is greater than 1:1, and is usually greater than 1.2:1 and may be as high as 4.5:1 or greater. In contrast, the equivalent ratio of a metal moiety to acid moiety in “normal” or “neutral” metal salts is 1:1, and in “low-based” salts it is less than 1:1. Thus, the overbased material usually contains greater than 20% in excess of the metal present in the corresponding neutral material. For this reason overbased metal salts have a greater capability for neutralising acidic matter than do the corresponding neutral salts, though not necessarily an increased detergency power.
For environmental reasons it has become desirable to minimise the amount of sulphur in such materials, due to the resulting sulphur dioxide emissions associated with lubricant combustion in service, as well as in additive production. In response to the perceived desirability of providing sulphur-free overbased metal salts suitable for use as detergent additives in lubricating oils EP 0 450 874 discloses a non-sulphurised overbased metal salt of a sulphur-free calixarene having a substituent hydroxyl group or groups available for reaction with a metal base and their preparation by reacting at elevated temperature:
(A) either (i) a sulphur-free calixarene having a substituent hydroxyl group or groups available for reaction with metal base, (ii) a low-based metal calixarate, (iii) a neutral metal calixarate or (iv) an overbased metal calixarate,
(B) a metal base added either in a single addition or in a plurality of additions at intermediate points during the reaction,
(C) a solvent comprising either: (C
1
) either (i) a polyhydric alcohol having 2 to 4 carbon atoms, (ii) a di-(C
3
or C
4
) glycol, (iii) a tri-(C
2
-C
4
) glycol or (iv) a mono-or poly-alkylene glycol alkyl ether of the formula:
R
9
(OR
10
)
f
O R
11
(II)
wherein in the formula (II) R
9
is a C
1
to C
6
alkyl group, R
10
is an alkylene group, e.g. of 1-6 or 2-4 carbon atoms, R
11
is hydrogen or a C
1
to C
6
alkyl group and f is an integer from 1 to 6; either alone or in combination with either: (C
2
) a hydrocarbon solvent; or (C
3
) either (i) water, (ii) C
1
to C
20
monohydric alcohol, (iii) a C
1
to C
2
ketone, (iv) a C
1
to C
10
carboxylic acid ester or (v) an aliphatic, alicyclic or aromatic C
1
to C
20
ether; or (C
4
) a C
1
to C
4
monohydric alcohol, in combination with a hydrocarbon solvent;
(D) carbon dioxide added subsequent to each addition of component (B).
EP 0 755 988 discloses the use of sulphur-free calixarenes having a molecular weight of at least 1880 for achieving high AV (Alkalinity Values as measured by the method of ASTM D2896), typically of at least 370, for example about 450, and potentially as high as 500 or more.
While reasons exist for making sulphur-free products as described above, it is not necessary in all situations to have detergents which are entirely free of sulphur. With the present invention it has been discovered that AVs in excess of 400 can in fact be achieved at molecular weights below 1880 when the calixarene contains sulphur.
SUMMARY OF THE INVENTION
This invention relates to a composition comprising at least one sulphur-containing calixarene represented by formula (I)
or a metal salt of said calixarene, wherein in formula (I): Y is a divalent bridging group, at least one of said bridging groups being a sulphur atom; R
3
is hydrogen, a hydrocarbyl or a hetero-substituted hydrocarbyl group; either R
1
is hydroxyl and R
2
and R
4
are independently either hydrogen, hydrocarbyl or hetero-substituted hydrocarbyl, or R
2
and R
4
are hydroxyl and R
1
is either hydrogen, hydrocarbyl or hetero-substituted hydrocarbyl; and n is a number having a value of at least 4. In one embodiment, the foregoing salt is an overbased salt. The invention also relates to additive compositions and finished lubricating oil compositions containing the foregoing overbased salt. The invention also relates to a process for making the foregoing overbased salt.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The sulphur-containing calixarenes of the invention are represented by the formula
In formula (I), Y is a divalent bridging group or a sulphur atom with the proviso that at least one Y group is a sulphur atom. The divalent bridging group, when not a sulphur atom, can be a divalent hydrocarbon group or divalent hetero-substituted hydrocarbon group of 1 to 18 carbon atoms, and in one embodiment 1 to 6 carbon atoms. The hetero atoms can be —O—, —NH— or —S—. n is an integer which typically has a value of at least 4, and in one embodiment the value of n is from 4 to 12, and in one embodiment 4 to 8. In one embodiment, n-2 to n-6 of the Y groups are sulphur atoms, and in one embodiment n-3 to n-10 of the Y groups are sulphur atoms, and in one embodiment one of the Y groups is a sulphur atom. In one embodiment, the amount of sulphur incorporated in the calixarene is between 5 and 50 mole %, such that between 5 and 50% of the groups Y in formula (I) are sulphur atoms. In one embodiment, the amount of sulphur is between 8 and 20 mole %.
In one embodiment, when Y is not a sulphur atom it is a divalent group represented by the formula (CHR
6
)
d
in which R
6
is either hydrogen, hydrocarbyl, or a hetero-substituted hydrocarbyl group and d is an integer which is at least one. R
6
can be a hydrocarbyl group or a hetero-substituted hydrocarbyl group of 1 to 18 carbon atoms, and in one embodiment 1 to 6 carbon atoms. Examples include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and the like. In one embodiment d is from 1 to 3, and in one embodiment 1 to 2, and in one embodiment d is 1. The hetero-substituted hydrocarbyl groups are those in which the heteroatom, typically —O—, —NH— or —S—, interrupts a chain of carbon atoms, an example being an alkoxy-alkyl group of 2 to 20 carbons.
R
3
is hydrogen, a hydrocarbyl or a hetero-substituted hydrocarbyl group. R
3
may be a hydrocarbyl group derived from a polyolefin, for example polyethylene, polypropylene, polybutylene or polyisobutylene, or a polyolefin copolymer, for example an ethylene/propylene copolymer. Examples of R
3
include dodecyl and octadecyl. The hetero atoms can be —O—, —NH— or —S—. These hydrocarbyl groups and hetero-substituted hydrocarbyl groups typically have 1 to 20 carbon atoms, and in one embodiment 1 to 6 carbon atoms.
Either R
1
is hydroxyl and R
2
and R
4
are independently either hydrogen, hydrocarbyl or hetero-substituted hydrocarbyl, or R
2
and R
4
are hydroxyl and R
1
is either hydrogen, hydrocarbyl or hetero-substituted hydrocarbyl. In one embodiment, R
1
is hydrogen, R
2
and R
1
are hydroxyl, and R
3
is either hydrogen, hydrocarbyl or hetero—substituted hydrocarbyl in the formula (I) and the calixarene is a resorcinarene. The hydrocarbyl groups and hetero-substituted hydrocarbyl groups typically have 1 to 24 carbon atoms, and in one embodiment 1 to 12 carbon atoms. The hetero atoms of such hereto-substituted hydrocarbyl groups can be —O—, —NH—, or —S—.
In one embodiment, Y is either sulphur or (CR
7
R
8
)
e
, where either one of R
7
and R
8
is hydrogen and the other is hydrogen or hydrocarbyl; R
2
and R
4
are independently either hydrogen,
Esposito, Esq. Michael F.
Lubrizol Adibis Holdings (UK) Limited
Medley Margaret
Toomer Cephia D.
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