Note: Descriptions are shown in the official language in which they were submitted.
U092/18~X- PCT/US92/nl476
20~53~2
Title: OVERBACED ALKALI METAL SALTS AND ME~ODS FOR
MAKING THE SAME
FIELD OF THE INVENTION
This invention relates to novel overbased alkali
metal salts of sulfonic acids, carboxylic acids, phenols or
mixtures thereof.
INTRODUCTION TO THE INVENTION
Alkali metal overbased metal salts of many
organic acids are known compounds and are useful in numer-
ous applications including lubricating compositions. The
compounds are prepared by reacting an acidic material with
a reaction mixture comprising basic metal compounds, an
acidic organic compound or salt and a promoter. Generally,
the acidic material is carbon dioxide and the promoters are
usually lower alkyl alcohols, usually methanol, ethanol or
butanol or lower alkyl acids.
In the overbasing process, the promoter improves
contact between the acidic material and the basic metal
compound. The result is an oil-ssluble or dispersible form
of the basic metal-acidic material salt, usually a metal
carbonate. Procedures for making these overbased compounds
are generally known.
Canadian Patent 1,055,700 relates to basic alkali
sulfonate dispersions and processes. U.S. Patent 4,326,972
relates to concentrates, lubricant compositions and methods
for improving fuel economy of internal combustion engines.
These compositions have as an essential ingredient a
specific sulfurized composition and a basic alkali metal
sulfonate. U.S. Patent 4,904,401 relates to lubricating
oil compositions. These compositions may contain a basic
alkali metal salt of at least one sulfonic or carboxylic
acid. U.S. Patent 4,938,881 relates to lubricating oil
compositions and concentrates. ~hese compositions and
concentrates include at least one basic alkali metal salt
wo~2/l8s8- Pcr/ US92/01476
(
,~ G~
--2--
of sulfonic or carboxylic acid. u.s. Patent 4,952,328
relates to lubricating oil compositions. These composi-
tions contain from about 0.01% to about 2% by weight of at
least one basic alkali metal salt of sulfonic or carboxylic
acid.
It has been discovered that overbased alkali
metal salts of high molecular weight acidic organic com-
pounds may be prepared. One of the problems associated
with working with high molecular weight material is effec-
tively providing contact between the acidic material ove~-
basing and the alkali metal compounds. Generally, previ-
ously used low molecular weight, i.e. highly volatile,
materials are ineffective as promoters for high molecular
weight acidic organic compounds in providing the contact
necessary to produce useful overbased compounds. Further-
more, the temperature used to overbase high molecular
weight acidic organic compounds generally exceeds the
boiling point of highly volatile promoters. The high
molecular weight alkali metal salts are useful in many
applications including lubricating applications. These
compounds provide strongly basic components (alkali metal-
acidic material, usually alkali metal carbonate) along with
high molecular weight, solubilizing substitutents.
SUMMARY OF THE INVENTION
The invention relates to a composition, compris-
ing:
at least one basic alkali metal salt of at least
one hydrocarbyl-substituted acidic organic compound,
wherein the hydrocarbyl group is derived from a polyalkene
having an Mn of at least 600, provided that when the
organic compound is a sulfonic acid, the polyalkene has an
Mn of at least 900; and provided that when the acidic
organic compound is a mixture of acidic organic compounds
containing a carboxylic acid and a sulfonic acid which has
a hydrocarbyl group derived from a polyalkene having an Mn
~092/18~- PCI~/US92/01476
20~372
--3--
o~ less than soo, then the carboxylic acid comprises at
least 10% of the equivalents of the mixture.
The invention also relates to a process for
preparing basic alkali metal salts of acidic organic
compounds comprising the steps of:
(A) adding at least one basic alkali metal
compound to a reaction mixture comprising at least one
alkali metal salt of a hydrocarbyl-substituted acidic
organic composition and removing free water from the
reaction mixture; and
(B) concurrently, thereafter
(1) adding at least one basic alkali metal
compound to the reaction mixture,
(2) adding at least one inorganic or lower
carboxylic acidic material to the reaction mixture, and
(3) removing water from the reaction
mixture, wherein the reaction temperature is sufficient to
form an oil-soluble overbased alkali metal salt.
The overbased compositions of the present inven-
tion are useful in many applications including paints,inks, coating, ceramics processing and lubricating applica-
tions. These lubricants include crankcase lubricating oils
for spark-ignited and compression-ignited internal combus-
tion engines, including automobile and truck engines, two-
cycle engines, aviation piston engines, marine and railroaddiesel engines, and the like. They can also be used in gas
engines, stationary power engines and turbines and the
like. Automatic transmission fluids, transaxle lubricants,
gear lubricants, metal-working lubricants, hydraulic fluids
and other lubricating oil and grease compositions can also
benefit from the incorporation therein of the compositions
of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The term "hydrocarbyl" includes hydrocarbon, as
well as substantially hydrocarbon, groups. Substantially
WOs2/lx~8- PCT/U592/01476
.,'3,~?. ,
~Q -4-
hydrocarbon describes groups which contain non-hydrocarbon
substituents which do not alter the predominately hydrocar-
bon nature of the group.
Examples of hydrocarbyl groups include the
following:
(1) hydrocarbon substituents, that is, aliphatic
(e.g., alkyl or alkenyl), alicyclic (e.g., cycloalkyl,
cycloalkenyl) substituents, aromatic-, aliphatic- and
alicyclic-substituted aromatic substituents and the like as
well as cyclic substituents wherein the ring is completed
through another portion of the molecule (that is, for
example, any two indicated substituer.ts may together form
an alicyclic radical);
(2) substituted hydrocarbon substituents, that
is, those substituents containing non-hydrocarbon groups
which, in the context of this invention, do not alter the
predominantly hydrocarbon substituent; those skilled in the
art will be aware of such groups (e.g., halo (especially
chloro and fluoro), hydroxy, alkoxy, mercapto, alkylmer-
capto, nitro, nitroso, sulfoxy, etc.);
(3) hetero substituents, that is, substituentswhich will, while having a predominantly hydrocarbon
character within the context of this invention, contain
other than carbon present in a ring or chain otherwise
composed of carbon atoms. Suitable heteroatoms will be
apparent to those of ordinary skill in the art and include,
for example, sulfur, oxygen, nitrogen and such substituents
as, e.g., pyridyl, furyl, thienyl, imidazolyl, etc. In
general, no more than about 2, preferably no more than one,
non-hydrocarbon substituent will be present for every ten
carbon atoms in the hydrocarbyl group. Typically, there
will be no such non-hydrocarbon substituents in the hydro-
carbyl group. Therefore, the hydrocarbyl group is purely
hydrocarbon.
wo92/l8sx- PCT/US92/01476
2n~ 37~
The present lubricating compositions contain an
alkali metal basic salt of a carboxylic acid, sulfonic
acid, phosphorus acid or a phenol. These basic salts are
often referred to as overbased salts. The overbased salts
are single phase, homogeneous Newtonian systems character-
ized by a metal content in excess of that which would be
present according to the stoichiometry of the metal and the
particular organic compound reacted with the metal. The
amount of excess metal is commonly expressed in metal
ratio. The term "metal ratio" is the ratio of the total
equivalents of the metal to the equivalents of the acidic
organic compound. A neutral metal salt has a metal ratio
of one. A salt having 4.5 times as much metal as present
in a normal salt will have metal excess of 3.5 equivalents,
or a ratio of 4.5. In the present invention, these salts
preferably have a metal ratio from about 1.5 to about 40,
preferably about 3 to about 30, more preferably about 3 to
about 25.
The overbased materials are prepared by reacting
an acidic material, typically carbon dioxide, with a
mixture comprising a carboxylic acid, a sulfonic acid,
phosphorus acid or a phenol, a reaction medium comprising
at least one inert, organic solvent for said organic
material, a stoichiometric excess of the above-described
metal compound, and a promoter. Preferably, the overbased
materials are prepared with carboxylic acids or sulfonic
acids. The carboxylic and sulfonic acids may have sub-
stituent groups derived from the polyalkenes. The polyal-
kene is characterized as containing from at least about 45,
preferably at least about 50, more preferably about 60, up
to about 300 carbon atoms, generally about 200, preferably
about 100, more preferably about 80. In one embodiment,
the polyalkene is characterized by an Mn (number average
molecular weight) value of at least about 600. Generally,
the polyalkene is characterized by an Mn value of about
uos2/l8sx~ ~ ~ PCT~US92/0l476
3~
600, preferably about 700, more preferably about 800, still
more preferably about 900 up to about S000, preferably
2500, more preferably 20~0, still more preferably about
1500. In another embodiment Mn varies between about 600,
preferably about 700, more preferably about 800 to about
1200 or 1300.
The abbreviation Mn is the conventional symbol
representing number average molecular weight. Gel perme-
ation chromatography (GPC) is a method which provides both
weight average and number average molecular weights as well
as the entire molecular weight distribution of the poly-
mers. For purpose of this invention a series of fraction-
ated polymers of isobutene, polyisobutene, is used as the
calibration standard in the GPC.
The techniques for determining Mn and Mw values
of polymers are well known and are described in numerous
books and articles. For example, methods for the determi-
nation of Mn and molecular weight distribution of polymers
is described in W.W. Yan, J.J. Kirkland and D.D. Bly,
"Modern Size Exclusion Liquid Chromatographs", J. Wiley &
Sons, Inc., 1979.
The polyalkenes include homopolymers and inter-
polymers of polymerizable olefin monomers of 2 to about 16
carbon atoms; usually 2 to about 6, preferably 2 to about
4, more preferably 4. The olefins may be monoolefins such
as ethylene, propylene, 1-butene, isobutene, and 1-octene;
or a polyolefinic monomer, preferably diolefinic monomer,
such as 1,3-butadiene and isoprene. The polyalkenes are
prepared by conventional procedures.
Suitable carboxylic acids from which useful
alkali metal salts can be prepared include aliphatic,
cycloaliphatic and aromatic mono- and polybasic carboxylic
acids free from acetylenic unsaturation, including naph-
thenic acids, alkyl- or alkenyl-substituted cyclopentanoic
acids, alkyl- or alkenyl-substituted succinic acids or
WO92/185X- PCT/US92/01476
20~372
--7--
anhydrides, alkyl- or alkenyl-substituted cyclohexanoic
acids, and alkyl- or alkenyl-substituted aromatic carboxyl-
ic acids. The acids are generally prepared by reacting an
unsaturated acid or derivative thereof with one of the
above-described polyalkenes or derivative thereof. Gener-
ally, the unsaturated acid is an alpha, beta unsaturated
carboxylic acid. Examples of these acids include maleic,
itaconic, citraconic, glutaric, crotonic, acrylic, and
methacrylic acids or derivatives thereof. The derivatives
of the unsaturated carboxylic acid include acids, anhy-
drides, metal or amine salts, lower alkyl esters (C17 alkyl
esters), and the like.
Illustrative carboxylic acids include propylenyl-
substituted glutaric acid, polybutenyl-substituted succinic
acids derived from a polybutene (Mn equals about 20C-1,500,
preferably about 300-1500), propenyl-substituted succinic
acids derived from polypropylenes (Mn equal 200-1000),
acids, acids formed by oxidation of petrolatum or of
hydrocarbon waxes, available mixtures of two or more
carboxylic acids and mixtures of these acids, their metal
salts, and/or their anhydrides.
In one embodiment, the carboxylic acids are
aromatic carboxylic acids. A group of useful aromatic
carboxylic acids are those of the formula
lXI
( c--XI;) b
(Rl), Ar /
\ (XH)c
wherein R~ is an aliphatic hydrocarbyl group preferably
derived from the above-described polyalkenes, a is a number
in the range of 1 to about 4, usually 1 or 2, Ar is an
aromatic group, each X is independently sulfur or oxygen,
preferably oxygen, b is a number in the range of from 1 to
~0 92/18~X- PC'I/l,'S92/0147fi
-8-
about 4, usually 1 or 2, c is a number in the range of zero
to about 4, usually 1 to 2, with the proviso that the sum
of a, b and c does not exceed the number of valences of Ar.
Examples of aromatic carboxylic acids include substituted
benzoic, phthalic and salicylic acids.
The R~ group is a hydrocarbyl group that is
directly bonded to the aromatic group Ar. Examples of Rl
groups include substituents derived from polymerized
olefins such as polyethylenes, polypropylenes, polybutyl-
enes, ethylene-propylene copolymers, chlorinated olefin
polymers and oxidized ethylene-propylene copolymers.
The aromatic group Ar may have the same structure
as any of the aromatic groups Ar discussed below. Examples
of the aromatic groups that are useful herein include the
polyvalent aromatic groups derived from benzene, naph-
thalene, anthracene, etc., preferably benzene. Specific
examples of Ar groups include phenylenes and naphthylene,
e.g., methylphenylenes, ethoxyphenylenes, isopropylphenyl-
enes, hydroxyphenylenes, dipropoxynaphthylenes, etc.
Within this group of aromatic acids, a useful
class of carboxylic acids are those of the formula
(COOH) b
~
(R~),
`(OH)~
wherein R, is defined above, a is a number in the range of
from 1 to about 4, preferably 1 to about 3; b is a number
in the range of 1 to about 4, preferably 1 to about 2, c is
a number in the range of zero to about 4, preferably 1 to
about 2, and more preferably 1; with the proviso that the
sum of a, b and c does not exceed 6. Preferably, b and c
are each one and the carboxylic acid is a salicylic acid.
WOs2/l8s8- PCT/US92/01476
9 20~5372
Overbased salts prepared from salicylic acids
wherein the aliphatic hydrocar~on substituents (R,) are
derived from the above-described polyalkenes, particularly
polymerized lower l-mono-olefins such as polyethylene,
S polypropylene, polyisobutylene, ethylene/propylene copoly-
mers and the like and having average carbon contents of
about 50 to about 400 carbon atoms are particularly useful.
The above aromatic carboxylic acids are well
known or can be prepared according to procedures known ïn
the art. Carboxylic acids of the type illustrated by these
formulae and processes for preparing their neutral and
basic metal salts are well known and disclosed, for exam-
ple, in U.S. Patents Z,197,832; 2,197,835; 2,252,662;
2,252,664; 2,714,092; 3,410,798; and 3,595,791. These
references are incorporated by reference for disclosure of
carboxylic acid, their basic salt and processes of making
the same.
The sulfonic acids useful in making the overbased
salts (A) of the invention include the sulfonic and thio-
sulfonic acids. Generally they are salts of sulfonicacids. The sulfonic acids include the mono- or polynuclear
aromatic or cycloaliphatic compounds. The oil-soluble
sulfonic acids can be represented for the most part by one
of the following formulae: R2-T-(SO3).H and R3-(S03)~,
wherein T is a cyclic nucleus such as, for example, ben-
zene, naphthalene, anthracene, diphenylene oxide, diphenyl-
ene sulfide, petroleum naphthenes, etc. Specific examples
of R2 and R~ are groups derived from petrolatum, saturated
and unsaturated paraffin wax, and the above-described
polyalkenes. The groups T, R2, and R3 in the above Formulae
can also contain other inorganic or organic substituents in
addition to those enumerated above such as, for example,
hydroxy, mercapto, halogen, nitro, amino, nitroso, sulfide,
disulfide, etc. In the above Formulae, a and b are at
least 1.
WO92/lX~8/ PCT/US92~01~76
J
--10--
Illustrative examples of these sulfonic acids
include polybutene or polypropylene substituted naphthalene
sulfonic acids, sulfonic acids derived by the treatment of
polybutenes having a number average molecular weight (Mn)
in the range of 700 to 5000, preferably 700 to 1200, more
preferably about 1500 with chlorosulfonic acids, paraffin
wax sulfonic acids, polyethylene (Mn e~uals about 900-2000,
preferably about 900-1500, more preferably 903-1200 or
1300) sulfonic acids, etc. Preferred sulfonic acids are
mono-, di-, and tri-alkylated benzene (including hydroge-
nated forms thereof) sulfonic acids.
In another embodiment, the hydrocarbyl-substi-
tuted acidic organic compound is a phenol. The phenol may
be a coupled or uncoupled phenol, preferably a substituted
phenol. The phenols may be alkylene coupled, wherein the
alkylene group contains from 1 to about 8 carbon atoms,
preferably 1 to about 4 carbon atoms, more preferably 1
carbon atom. Alkylene coupled phenols are prepared by
procedures known to those in the art. Generally, the
phenol is reacted with an aldehyde, usually formaldehyde or
a f ormaldehyde precursor such as paraformaldehyde, at a
temperature from about 50C to about 175C. A diluent may
be used such as mineral oil, naphtha, kerosene, toluene or
xylene.
The phenol may be a sulfur-coupled phenol which
is prepared by reacting a sulfurizing agent with the
phenol. The sulfurizing agent generally is elemental
sulfur or a sulfur halide, such as sulfur monochloride or
sulfur dichloride, preferably sulfur dichloride. Sulfur
coupled phenols, also referred to as polyphenol sulfides,
are generally prepared by reacting a sulfur halide with a
phenol at a temperature from about 50C to about 75C. The
diluent as described above may also be used.
In a preferred embodiment, the phenol is substi-
tuted with one of the polyalkene groups described above.
u~092/18s8 PC~/VS9Z/01476
208~372
Preferably, the phenol has a polybutene or polypropylene
substituent having a number average molecular weight of
about 700 to about 1200 or 1300.
The phenols useful in making the overbased salts
of the invention can be represented by the formula (R~ Ar-
(OH)~, wherein Rl is defined above; Ar is an aromatic group;
a and b are independently numbers of at least one, the sum
of a and b being in the range of two up to the number of
displaceable hydrogens on the aromatic nucleus or nuclei of
Ar. Preferably, a and b are independently numbers in tne
range of 1 to about 4, more preferably 1 to about 2. R~ and
a are preferably such that there is an average of at least
about 8 aliphatic carbon atoms provided by the R~ groups for
each phenol compound.
While the term "phenol~ is used herein, it is to
be understood that this term is not intended to limit the
aromatic group of the phenol to benzene. Accordingly, it
is to be understood that the aromatic group as represented
by "Ar", as well as elsewhere in other formulae in this
specification and in the appended claims, can be mononucle-
ar such as a phenyl, a pyridyl, or a thienyl, or polynucle-
ar. The polynuclear groups can be of the fused type
wherein an aromatic nucleus is fused at two points to
another nucleus such as found in naphthyl, anthranyl, etc.
The polynuclear group can also be of the linked type
wherein at least two nuclei (either mononuclear or polynu-
clear) are linked through bridging linkages to each other.
These bridging linkages can be chosen from the group
consisting of alkylene linkages, ether linkages, keto
linkages, sulfide linkages, polysulfide linkages of 2 to
about 6 sulfur atoms, etc.
The number of aromatic nuclei, fused, linked or
both, in Ar can play a role in determining the integer
values of a and b. For exa~ple, when ~r contains a single
aromatic nucleus, the sum of a and b is from 2 to 6. When
W092/1858-- PCT/US92/01476
3~
Ar contains two aromatic nuclei, the sum of a and b is from
2 to 10. With a tri-nuclear Ar moiety, the sum of a and b
is from 2 to 15. The value for the sum of a and b is
limited by the fact that it cannot exceed the total number
5of displaceable hydrogens on the aromatic nucleus or nuclei
of Ar.
The promoters, that is, these materials which
facilitate the incorporation of excess metal into the
overbased material act to improve contact between the
10acidic material and the acidic organic compound (overbasing
substrate). Generally, the promoter is a material which is
slightly acidic and able to form a salt with the basic
metal compound. The promoter must also be an acid weak
enough to be displaced by the acidic material, usually
15carbon dioxide. Generally, the promoter has a pKa in the
range from about 7 to about 10. A particularly comprehen-
sive discussion of suitable promoters is found in U.S.
Patents 2,777,874, 2,695,910, 2,616,904, 3,384,586 and
3,492,231. These patents are incorporated by reference for
20their disclosure of promoters. In one embodiment, promot-
ers include the phenolic promoters. Phenolic promoters
include a variety of hydroxy-substituted benzenes and
naphthalenes. A particularly useful class of phenols are
the alkylated phenols of the type listed in U.S. Patent
252,777,874, e.g., heptylphenols, octylphenols, and nonyl-
phenols. Mixtures of various promoters are sometimes used.
The inorganic or lower carboxylic acidic materi-
als, which are reacted with the mixture of promoter, basic
metal compound, reaction medium and acidic organic com-
30pound, are disclosed in the above cited patents, for
example, U.S. Patent 2,616,904. Included within the known
group of useful acidic materials are lower carboxylic
acids, having from 1 to about 8, preferably 1 to about 4
carbon atoms. Examples of these acids include formic acid,
35acetic acid, propanoic acid, etc., preferably acetic acid.
WO92/18~87 P~/US92/01476
2085372
-13-
Useful inorganic acidic compounds include HCl, 52~ S~3, C2~
H2S, N2O3, etc., are ordinarily employed as the acidi-
materials. Preferred acidic materials are carbon dioxide
and acetlc acid, ~ore preferably carbon dioxide.
The alkali metals present in the overbased alkali
metal salts include principally lithium, sodium and potas-
sium, with sodium being preferred. The overbased metal
salts are prepared using a basic alkali metal compound.
Illustrative of basic alkali metal compounds are hydrox-
ides, oxides, alkoxides (typically those in which t~e
alkoxy group contains up to 10 and preferably up to 7
carbon atoms), hydrides and amides of alkali metals. Thus,
useful basic alkali metal compounds include sodium oxide,
potassium oxide, lithium oxide, sodium hydroxide, potassium
hydroxide, lithium hydroxide, sodium propoxide, lithium
methoxide, potassium ethoxide, sodium butoxide, lithium
hydride, sodium hydride, potassium hydride, lithium amide,
sodium amide and potassium amide. Especially preferred are
sodium hydroxide and the sodium lower alkoxides (i.e.,
those containing up to 7 carbon atoms).
The overbased materials of the present invention
may be prepared by methods known to those in the art. The
methods generally involve adding acidic material to a
reaction mixture comprising the hydrocarbyl-substituted
acidic organic compound, the promoter and a basic alkali
metal compound. These processes are described in the
following U.S. Patent Nos.: 2,616,904; 2,616,905;
2,616,906; 3,242,080; 3,250,710; 3,256,186; 3,274,135;
3,492,231; and 4,230,586. These patents are incorporated
herein by reference for these disclosures.
In the present invention, the hydrocarbyl-substi-
tuted acidic organic materials have relatively high molecu-
lar weights. Higher temperatures are generally used to
promote contact between the acidic material, the acidic
organic compound and the basic alkali metal compound. The
W0 92/1 RSX~ ')2/~1 47f~
~^ ,~.
~'
-14-
higher temperatures also promote formation of the salt of
the weakly acidic promoter by removal of water. In prepar-
ing the overbased metal salts of the present invention,
water must be removed from the reaction.
The reaction generally proceeds at temperatures
from about 100C up to the decomposition temperature of the
reaction mixture or the individual components of the
reaction. The reaction may proceed at temperatures lower
than 100C, such as 60C or above, if a vacuum is applied.
Generally, the reaction occurs at a temperature from about
110C to about 200C, preferably 120C to about l75DC and
more preferably about 130C to about 150C. Preferably,
the reaction is performed in the presence of a reaction
medium which includes naphtha, mineral oil, xylenes,
toluenes and the like. In the present invention water may
be removed by applying a vacuum, by blowing the reaction
mixture with a gas such as nitrogen or by removing water as
an azeotrope, such as a xylene-water azeotrope. Generally,
in the present invention, the acidic material is provided
as a gas, usually carbon dioxide. The carbon dioxide,
while participating in the overbasing process, also acts to
remove water if the carbon dioxide is added at a rate which
exceeds the rate carbon dioxide is consumed in the reac-
tion.
2~ The overbased metal salts of the present inven-
tion may be prepared incrementally (batch) or by continuous
process. The incremental process involves the following
steps: (A) adding a basic alkali metal compound to a
reaction mixture comprising an acidic organic compound and
removing free water from the reaction mixture to form an
alkali metal salt of the acidic organic compound; (B)
adding the basic alkali metal compound to the reaction
mixture and removing free water from from the reaction
mixture; and (C) introducing the acidic material to the
reaction mixture while removing water. Steps (B) and (C)
~ 0 92!lxcx~ l/l X92/~147(
2 0 ~ ~ 3 7 2
-15-
are repeated until a product of the desired metal ratio is
obtained.
A novel aspect of the present invention is the
semi-continuous process for preparing the alkali metal
overbased salts of the present invention. The process
involves (A) adding at least one basic alkali metal com-
pound to a reaction mixture comprising an alkali metal salt
of an acidic organic compound and removing free water from
the reaction mixture; and (B) concurrently thereafter, (1)
adding basic alkali metal compound to the reaction mixture;
(2) adding an inorganic or lower carboxylic acidic material
to the reaction mixture; and (3) removing water from the
reaction mixtureO The inventors have discovered that the
addition of basic alkali metal compounds together with the
inorganic or lower carboxylic acidic material may be accom-
plished by a process where the addition is done continuous-
ly along with the removal of water. This process shortens
processing time of the reaction.
The term "free water" refers to the amount of
water readily removed from the reaction mixture. This
water is typically removed by azeotropic distillation. The
water which remains in the reaction mixture is believed to
be coordinated, associated, or solvated. The water may be
in the form of water of hydration. Some basic alkali metal
compounds may be delivered to the reaction mixture as
aqueous solutions. The excess water added, or free water,
with the basic alkali metal compound is usually then
removed by azeotropic distillation, or vacuum stripping.
Water is generated during the overbasing process
and is desirably removed as it is formed to minimize or
eliminate formation of oil-insoluble metal carbonates.
During the overbasing process above, the amount of water
present prior to addition of the inorganic or lower carbox-
ylic acidic material (steps (C) and (B-1) above) is less
than about 30% by weight of the reaction mixture, prefera-
~092/l8~X~ 1/1!$~2/0l47(,
~ 16-
bly 20%, more preferably 10%. Generally, the amount of
water present after addition of the inorganic or lower
carboxylic acidic material is up to about 4% by weight of
the reaction mixture, preferably about 3%, more preferably
about 2%.
When the process involves concurrent addition of
basic alkali metal compounds and inorganic or lower carbox-
ylic acidic materials, the hydrocarbyl group of the acidic
organic compound is derived from the above-described poly-
alkenes. The provisos related to the polyalkene of the
sulfonic acid and mixture of acidic organic compound are
only preferred embodiments.
In another embodiment, the alkali metal overbased
salts are borated alkali metal overbased salts. Borated
overbased metal salts are prepared by reacting a boron
compound with the basic alkali metal salt. Boron compounds
include boron oxide, boron oxide hydrate, boron trioxide,
boron trifluoride, boron tribromide, boron trichloride,
boron acid such as boronic acid, boric acid, tetraboric
acid and metaboric acid, boron hydrides, boron amides and
various esters of boron acids. The boron esters are
preferably lower alkyl (1-7 carbon atoms) esters of boric
acid. Preferably, the boron compounds are boric acid.
Generally, the overbased metal salt is reacted with a boron
2S compound at about 50C to about 250C, preferably 100C to
about 200C. The reaction may be accomplished in the
presence of a solvent such as mineral oil, naphtha, kero-
sene, toluene or xylene. The overbased metal salt is
reacted with a boron compound in amounts to provide at
least about 0.5%, preferably about 1% up to about 5%,
preferably about 4%, more preferably about 3% by weight
boron to the composition.
The following examples illustrate the alkali
metal overbased salts of the present invention and methods
of making the same. In the examples and elsewhere in the
WO~2/lX5X, ~lCI /U`S92/~1l 47~)
20 ~a 3 7~
-17-
specification r unless otherwise indicated, the temperature
is degrees Celsius, the amounts are weight percent, and the
pressure is atmospheric.
Example 1
A reaction vessel is charged with 1122 parts (2
equivalents) of a polybutenyl-substituted succinic anhy-
dride derived from a polybutene (Mn=1000), 105 parts (0.4
equivalent) of tetrapropenyl phenol, 1122 parts of xylene
and 1000 grams of lO0 neutral mineral oil. The mixture is
stirred and heated to 80C under nitrogen. Then, 580 parts
of a 50% aqueous solution of sodium hydroxide is added to
the vessel over 10 minutes. The mixture is heated from
80OC to 120C over 1.3 hours. Water is removed by azeo-
tropic reflux and the temperature rises to 150C over 6
hours while 300 parts of water is collected. (1) The
reaction mixture is cooled to 80C where 540 parts of a 50%
aqueous solution of sodium hydroxide is added to the
vessel. (2) The reaction mixture is heated to 140C over
1.7 hours and water is removed at reflux conditions. (3)
The reaction mixture is carbonated at 1 standard cubic foot
per hour (scfh) while removing water for 5 hours. Steps
(1)-(3) are repeated using 560 parts of an aqueous sodium
hydroxide solution. Steps (1)-(3) are repeated using 640
parts of an aqueous sodium hydroxide solution. Steps (1)-
(3) are then repeated with another 640 parts of a 50%
aqueous sodium hydroxide solution. The reaction mixture is
cooled and 1000 parts of lO0 neutral mineral oil are added
to the reaction mixture. The reaction mixture is vacuum
stripped to 115C, about 30 millimeters of mercury. The
residue is filtered through diatomaceous earth. The
filtrate has a total base number of 361 (theoretical 398),
43.4% sulfated ash (theoretical 50.3), 39.4% oil and a
specific gravity of 1.11.
WOs2/l858~ P~'r/~!S~2/~)l476
'~.;`~
Example 2
A reaction vessel is charqed with 700 parts of a
loo neutral mineral oil, 700 parts (1.25 equivalents) of
the succinic anhydride of Example 1 and 200 parts (2.5
equivalents) of a 50% aqueous solution of sodium hydroxide.
The reaction mixture is stirred and heated to 80C where 66
parts (0.25 equivalent) of tetrapropenyl phenol are added
to the reaction vessel. The reaction mixture is heated
from 80C to 140C over 2.5 hours with blowing of nitrogen
and removal of 40 parts of water. Carbon dioxide (28
parts, 1.25 equivalents) is added over 2.25 hours at a
temperature from 140-165C. The reaction mixture is blown
with nitrogen at 2 standard cubic foot per hour (scfh) and
a total of 112 parts of water is removed. The reaction
temperature is decreased to 115C and the reaction mixture
is filtered through diatomaceous earth. The filtrate has
4.06~ sodium (theoretical 3.66), a total base number of 89,
a specific gravity of 0.948 and 44.5% oil.
Example 3
A reaction vessel is charged with 281 parts (0.5
equivalent) of the succinic anhydride of Example 1, 281
parts of xylene, 26 parts of tetrapropenyl substituted
phenol and 250 parts of 100 neutral mineral oil. The
mixture is heated to 80C and 272 parts (3.4 equivalents)
of an aqueous sodium hydroxide solution are added to the
reaction mixture. The mixture is blown with nitrogen at 1
scfh and the reaction temperature is increased to 148C.
The reaction mixture is then blown with carbon dioxide at
1 scfh for one hour and 25 minutes while 150 parts of water
is collected. The reaction mixture is cooled to 80C where
272 parts (3.4 equivalents) of the above sodium hydroxide
solution is added to the reaction mixture and the mixture
is blown with nitrogen at 1 scfh. The reaction temperature
is increased to 140C where the reaction mixture is blown
with carbon dioxide at 1 scfh for 1 hour and 25 minutes
uo~2/l8~ 92/~l47~,
20~372
-19-
while 150 parts of water is collected. The reaction
temperature is decreased to 100C and 272 parts (3.4
equivalents) of the above sodium hydroxide solution is
added whlle blowing the mixture with nitrogen at 1 scfh.
The reaction temperature is increased to 148C and the
reaction mixture is blown with carbon dioxide at 1 scfh for
1 hour and 40 minutes while 160 parts of water is collect-
ed. The reaction mixture is cooled to 90C and where 250
parts of 100 neutral mineral oil are added to the reaction
mixture. ~he reaction mixture is vacuum stripped at 70C
and the residue is filtered through diatomaceous earth.
The filtrate contains 50.0% sodium sulfate ash (theoretical
53.8%) by ASTM D-874, total base number of 408, a specific
gravity of 1.18 and 37.1% oil.
Example 4
A reaction vessel is charged with 700 parts of
the product of Example 3. The reaction mixture is heated
to 75C where 340 parts (5.5 equivalents) of boric acid is
added sver 30 minutes. The reaction mixture is heated to
110C over 45 minutes and the reaction temperature is
maintained for 2 hours. A 100 neutral mineral oil (80
parts) is added to the reaction mixture. The reaction
mixture is blown with nitrogen at 1 scfh at 160C for 30
minutes while 95 parts of water is collected. Xylene (200
parts) is added to the reaction mixture and the reaction
temperature is maintained at 130-140C for 3 hours. The
reaction mixture is vacuum stripped at 150C and 20 milli-
meters of mercury. The residue is filtered through dia-
tomaceous earth. The filtrate contains 5.84% boron (theo-
retical 6.43) and 33.1% oil. The residue has a total base
number of 309.
Example 5
A reaction vessel is charged with 224 parts (0.4
equivalents) of the succinic anhydride of Example 1, 21
parts (0.08 equivalent) of a tetrapropenyl phenol, 224
wo~2/l8sX r(r/l~s92t()l47fi
-20-
parts of xylene and 224 parts of 100 neutral mineral oil.
The mixture is heated and 212 parts (2.65 equivalents) of
a 50% aqueous sodium hydroxide solution are added to the
reaction vessel. The reaction temperature increases to
130C and 41 parts of water is removed by nitrogen blowing
at 1 scfh. The reaction mixture is then blown with carbon
dioxide at 1 scfh for 1.25 hours. The sodium hydroxide
solution (432 parts, 5.4 equivalents) is added over four
hours with carbon dioxide ~lowing at 0.5 scfh at 130C.
During the addition, 301 parts of water are removed from
the reaction vessel. The reaction temperature is increased
to 150C and the rate of carbon dioxide blowing is in-
creased to 1.5 scfh and maintained for 1 hour and 15
minutes. The reaction mixture is cooled to 150C and blown
with nitrogen at 1 scfh while 176 parts of oil is added to
the reaction mixture. The reaction mixture is blown with
nitrogen at 1.8 scfh for 2.5 hours and the mixture is then
filtered through diatomaceous earth. The filtrate contains
15.7~ sodium and 39% oil. The filtrate has a total base
number of 380.
Example 6
A reaction vessel is charged with 561 parts (1
equivalent) of the succinic anhydride of Example 1, 52.5
parts (0.2 equivalent) of a tetrapropenylphenol, 561 parts
xylene and 500 parts of a 100 neutral mineral oil. The
mixture is heated to 50C under nitrogen and 373.8 parts
(6.8 equivalents) of potassium hydroxide and 299 parts of
water are added to the mixture. The reaction mixture is
heated to 135C while 145 parts of water is removed. The
azeotropic distillate is clear. Carbon dioxide is added to
the reaction mixture at l scfh for two hours while 195
parts of water is removed azeotropically. The reaction is
cooled to 75C where a second portion of 373.8 parts of
potassium hydroxide and 150 parts of water are added to the
reaction vessel. The reaction mixture is heated to 150C
~'092~1X~ lJX92~)l47~
20~5~7~
-21-
with azeotropic removal o~ 70 parts of water. Carbon
dioxide (1 scfh) is added for 2.5 hours while 115 parts of
water is removed azeotropically. The reaotion is cooled to
100C where a third portion of 373.8 parts of potassium
hydroxide and 150 parts of water is added to the vessel.
The reaction mixture is heated to 150C while 70 parts of
water is removed. The reaction mixture is blown with
carbon dioxide at 1 scfh for one hour while 30 parts of
water is removed. The reaction temperature is decreased to
70C. The reaction mixture is reheated to 150C under
nitrogen. At 150C the reaction mixture is blown with
carbon dioxide at 1 scfh for two hours while 80 parts of
water is removed. The carbon dioxide is replaced with a
nitrogen purge and 60 parts of water is removed. The
reaction is then blown with carbon dioxide at 1 scfh for
three hours with removal of 64 parts of water. The reac-
tion mixture i5 cooled to 75C where 500 parts of 100
neutral mineral is added to the reaction mixture. The
reaction is vacuum stripped to ll5DC and 25 millimeters of
mercury. The residue is filtered through diatomaceous
earth. The filtrate contains 35% oil and has a base number
of 322.
Example 7
An overbased sodium salt of a substituted phenol
is prepared by the process of Example 1 using 994 parts (1
equivalent) of polybutenyl-substituted phenol derived from
a polybutene (Mn=900) reacted with 1440 (18 equivalents) of
a 50% aqueous solution of sodium hydroxide.
Example 8
An overbased sodium sulfonate is prepared by the
process described in Example 6 by using 980 parts (1
equivalent) of a sodium polypropenyl-substituted benzene
sulfonate derived from a polypropene (Mn=800) and 800 parts
(10 equivalents) of a 50% aqueous solution of sodium
hydroxide.
W09~ 5X, PCr/~'.S92/~JI47h
-22-
Example 9
An overbased lithium carboxylate is prepared by
the process described in Example 1 using 1072 parts (1
equivalent) of a polybutenyl of carboxylate, prepared by
reacting polybutenyl chloride derived from a polybutene
(Mn=1000) and acrylic acid, which is reacted with 756 parts
(18 equivalents) of lithium hydroxide monohydrate.
Example 10
An overbased sodium sulfonate-carboxylate is
prepared by the process described in Example 1 using 5~2
parts of the succinic anhydride of Example 1 and 479 parts
of a polybutenyl-substituted sulfonic acid derived from a
polybutene (Mn=800) and 1632 parts (20.4 equivalents) of a
50% aqueous solution of sodium hydroxide.
Lubricatin~ ComDositions
The alkali metal overbased salts of the present
invention may be used, in lubricants or in concentrates, by
themselves or in combination with any other known additive
which includes, but is not limited to dispersants, deter-
gents, antioxidants, anti-wear agents, extreme pressure
agents, emulsifiers, demulsifiers, foam inhibitors, fric-
tion modifiers, anti-rust agents, corrosion inhibitors,
viscosity improvers, pour point depressants, dyes, and
solvents to improve handleability which may include alkyl
and/or aryl hydrocarbons. These additives may be present
in various amounts depending on the needs of the final
product.
Dispersants include, but are not limited to,
hydrocarbon substituted succinimides, succinamides, carbox-
ylic esters, Mannich dispersants and mixtures thereof as
well as materials functioning both as dispersants and
viscosity improvers. The dispersants include nitrogen-
containing carboxylic dispersants, ester dispersants,
Mannich dispersants or mixtures thereof. Nitrogen-contain-
ing carboxylic dispersants are prepared by reacting a
WO92/1X~X- ~cr/us92/l~l47~
208.~3 7~
-23-
hydrocarbyl carboxylic acylating agent (usually a hydro-
carbyl substituted succinic anhydride) with an amine
(usually a polyamine). Ester dispersants are prepared by
reacting a polyhydroxy compound with a hydrocarbyl carbox-
ylic acylating agent. The ester dispersant may be furthertreated with an amine. ~annich dispersants are prepared by
reacting a hydroxy aromatic compound with an amine and
aldehyde. The dispersants listed above may be post-treated
with reagents such as urea, thiourea, carbon disulfide,
aldehydes, ketones, carboxylic acids, hydrocarbon substi-
tuted succinic anhydride, nitriles, epoxides, boron com-
pounds, phosphorus compounds and the like.
Detergents include, but are not limited to,
Newtonian or non-Newtonian, neutral or basic salts of
alkaline earth or transition metals with one or more
hydrocarbyl sulfonic acid, carboxylic acid, phosphoric
acid, thiophosphoric acid, dithiophosphoric acid, phos-
phinic acid, thiophosphinic acid, sulfur coupled phenol or
phenol. Basic salts are salts that contain a stoichiomet-
ric excess of metal present per acid function.
Auxiliary extreme pressure agents and corrosion-
and oxidation-inhibiting agents which may be included in
the lubricants of the invention are exemplified by chlori-
nated aliphatic hydrocarbons such as chlorinated wax;
organic sulfides and polysulfi~es such as benzyl disulfide,
bis(chlorobenzyl)disulfide, dibutyl tetrasulfide, sulfu-
rized methyl ester of oleic acid, sulfurized alkylphenol,
sulfurized dipentene, and sulfurized terpene; phospho-
sulfurized hydrocarbons such as the reaction product of a
phosphorus sulfide with turpentine or methyl oleate,
phosphorus esters including principally dihydrocarbon and
trihydrocarbon phosphites such as dibutyl phosphite,
diheptyl phosphite, dicyclohexyl phosphite, pentylphenyl
phosphite, dipentylphenyl phosphite, tridecyl phosphite,
distearyl phosphite, -dimethyl naphthyl phosphite, oleyl
wos2/lNsx~ r~/ U~92/01476
-24-
4-pentylphenyl phosphite, polypropylene (molecular weight
500)-substituted phenyl phosphite, diisobutyl-substituted
phenyl phosphite; metal thiocarbamates, such as zinc
dioctyldithiocarbamate, and barium heptylphenyl dithio-
carbamate; boron-containing compounds including borate
esters; molybdenum compounds; Group II metal phosphorodi-
thioates such as zinc dicyclohexylphosphorodithioate, zinc
dioctylphosphorodithioate, barium di(heptylphenyl)-phos-
phorodithioate, cadmium dinonylphosphorodithioate, and the
zinc salt of a phosphorodithioic acid produced by the
reaction of phosphorus pentasulfide with an equimolar
mixture of isopropyl alcohol and n-hexyl alcohol.
Viscosity improvers include, but are not limited
to, polyisobutenes, polymethacrylate acid esters, poly-
acrylate acid esters, diene polymers, polyalkyl styrenes,
alkenyl aryl conjugated diene copolymers, polyolefins and
multifunctional viscosity improvers.
Pour point depressants are a particularly useful
type of additive often included in the lubricating oils
described herein. See for example, page 8 of "Lubricant
Additives" by C. V. Smalheer and R. Kennedy Smith (Lesius-
Hiles Company Publishers, Cleveland, Ohio, 1967).
Anti-foam agents used to reduce or prevent the
formation of stable foam include silicones or organic
polymers. Examples of these and additional anti-foam
compositions are described in "Foam Control Agents", by
Henry T. Kerner (Noyes Data Corporation, 1976), pages 125-
162.
These and other additives are described in
greater detail in U.S. Patent 4,582,618 (column 14, line 52
through column 17, line 16, inclusive), herein incorporated
by reference for its disclosure of other additives that may
be used in combination with the present invention.
The concentrate might contain 0.01 to 90~ by
weight of the alXali metal overbased salts. The alkali
w~s2/l8sx~ l'Cr/0.~92/~)147~)
208~37~
metal overbased salts may be present in a final product,
blend or concentrate in (in a minor amount, i.e., up to 50%
by weight) any amount effective to act as a detergent, but
is preferably present in oil of lu~ricating viscosity,
hydraulic oils, fuel oils, gear oils or automatic transmis-
sion fluids in an amount of from about 0.1 to about 10%,
preferably 0.25 to about 2% by weight, most preferably
about 0.50 to about 1.25%.
The lubricating compositions and methods of this
invention employ an oil of lubricating viscosity, including
natural or synthetic lubricating oils and mixtures thereof.
~atural oils include animal oils, vegetable oils, mineral
lubricating oils, solvent or acid treated mineral oils, and
oils derived from coal or shale. Synthetic lubricating oils
include hydrocarbon oils, halo-substituted hydrocarbon
oils, alkylene oxide polymers, esters of carboxylic acids
and polyols, esters of polycarboxylic acids and alcohols,
esters of phosphorus-containing acids, polymeric tetra-
hydrofurans, silicon-based oils and mixtures thereof.
Specific examples of the oils of lubricating
viscosity are described in U.S. Patent 4,326,972 and
European Patent Publication 107,282, both herein incorpo-
rated by reference for ~heir disclosures relating to
lubricating oils. A basic, brief description of lubricant
base oils appears in an article by D. V. Brock, "Lubricant
Base Oils", Lubricant Enaineerina, volume 43, pages 184-
185, March, 1987. This article is herein incorporated by
reference for its disclosures relating to lubricating oils.
A description of oils of lubricating viscosity occurs in
U.S. Patent 4,582,618 (column 2, line 37 through column 3,
line 63, inclusive), herein incorporated by reference for
its disclosure to oils of lubricating viscosity.
The following examples illustrate lubricating
compositions of the present invention. The amount of each
WOg2/l~sg- r~ S92
,. '` ~l'?~
-2~-
component in Examples A-C reflects the amount of oil
containing product of the indicated additives.
Lubricant (% weight)
S
Component A B C
Product of Example 1 0.76 1.04 1.04
~eaction product of poly- 5.7 6.25 6.25
butene succinic anhydride
~Polybutene Mn=1845) and
ethylene polyamines
Zinc-isopropyl,metAylamyl 0.9 1.12 1.1
dithiophosphate
Methylene-bis(6-t-butyl- 0.33 0.32 ---
4-tetrapropenyl phenol)
2,6-di-t-butyl-4-tetra- --- --- 0.37
propenyl phenol
Copper-O,O'isopropyl, 0.08 0.1 0.1
methylamyl dithiophosphate
Glycerolmonooleate or 0.1 0.1 0.1
oleylamide
8% by weight hydrogenated 9.5 9.0 10.0
styrene-butadiene copolymer
in 100 neutral mineral oil
Silicon antifoam agent 80 ppm 80 ppm 80 ppm
Oil Balance Balance Balance
The lubricating oil compositions of the present
invention exhibit a reduced tendency to deteriorate under
conditions of use and thereby reduce rust and corrosive
wear and the formation of such undesirable deposits as
varnish, sludge, carbonaceous materials and resinous
materials which tend to adhere to the various engine parts
and reduce the efficiency of the engines. Lubricating oils
also can be formulated in accordance With this invention
WV92/185X, pcT/~Js92/nl47~
20~372
-27-
which result in improved fuel economy when used in the
crankcase of a passenger automobile.
While the invention has been explained in rela-
tion to its preferred embodiments, it is to be understood
that various modifications thereof will become apparent to
those skilled in the art upon reading the specification.
Therefore, it is to be understood that the invention
disclosed herein is intended to cover such modifications as
fall within the scope of the appended claims.
