U.S. patent application number 11/850730 was filed with the patent office on 2008-03-20 for lubricating oil composition.
Invention is credited to Stephen Arrowsmith, Laura Kosidowski, Jeremy R. Spencer, Peter D. Watts.
Application Number | 20080070818 11/850730 |
Document ID | / |
Family ID | 37905856 |
Filed Date | 2008-03-20 |
United States Patent
Application |
20080070818 |
Kind Code |
A1 |
Arrowsmith; Stephen ; et
al. |
March 20, 2008 |
Lubricating Oil Composition
Abstract
A lubricating oil composition including at least one sulphurized
overbased metal phenate detergent prepared from a C.sub.9-C.sub.15
alkyl phenol, at least one sulphurizing agent, at least one metal
and at least one overbasing agent. The detergent includes less than
6.0% by combined mass of unsulphurized C.sub.9-C.sub.15 alkyl
phenol and its unsulphurized metal salt. The lubricating oil
composition exhibits an improved rate of acid neutralization.
Inventors: |
Arrowsmith; Stephen;
(Didcot, GB) ; Kosidowski; Laura; (Marlborough,
GB) ; Spencer; Jeremy R.; (Didcot, GB) ;
Watts; Peter D.; (Abingdon, GB) |
Correspondence
Address: |
INFINEUM USA L.P.
P.O. BOX 710
LINDEN
NJ
07036
US
|
Family ID: |
37905856 |
Appl. No.: |
11/850730 |
Filed: |
September 6, 2007 |
Current U.S.
Class: |
508/574 |
Current CPC
Class: |
C10N 2030/52 20200501;
C10N 2040/252 20200501; C10N 2010/02 20130101; C10N 2070/00
20130101; C10M 2219/089 20130101; C10M 2207/126 20130101; C10M
159/22 20130101; C10N 2030/04 20130101 |
Class at
Publication: |
508/574 |
International
Class: |
C10M 159/22 20060101
C10M159/22 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 19, 2006 |
EP |
06120924.3 |
Claims
1. A lubricating oil composition including at least one sulphurized
overbased metal phenate detergent prepared from a C.sub.9-C.sub.15
alkyl phenol, at least one sulphurizing agent, at least one metal
and at least one overbasing agent; the detergent including less
than 6.0% by combined mass of unsulphurized C.sub.9-C.sub.15 alkyl
phenol and unsulphurized metal salts thereof.
2. The composition as claimed in claim 1, wherein the sulphurized
overbased metal phenate detergent is prepared from a
C.sub.10-C.sub.13 alkyl phenol.
3. The composition as claimed in claim 1, wherein the sulphurized
overbased metal phenate detergent also includes at least one
further surfactant selected from a sulphonic acid or a carboxylic
acid.
4. The composition as claimed in claim 3, wherein the sulphurized
overbased metal phenate detergent includes stearic acid as a
further surfactant.
5. The composition as claimed in claim 1, wherein the sulphurizing
agent is sulphur monochloride.
6. The composition as claimed in claim 1, wherein the metal is
calcium.
7. The composition as claimed in claim 1, wherein the overbased
metal phenate detergent has been prepared using a carbonation
temperature of less than 100.degree. C., preferably less than
80.degree. C.
8. The composition as claimed in claim 7, wherein the overbased
metal phenate detergent has been prepared using a carbonation
temperature of less than 80.degree. C.
9. The composition as claimed in claim 1, wherein the overbasing
agent is carbon dioxide.
10. A method of increasing the rate of acid neutralization of a
lubricating oil composition, the method including the step of
adding to the lubricating oil composition at least one sulphurized
overbased metal phenate detergent prepared from a C.sub.9-C.sub.15
alkyl phenol, at least one sulphurizing agent, at least one metal
and at least one overbasing agent; the sulphurized overbased metal
phenate detergent including less than 6.0% by combined mass of
unsulphurized C.sub.9-C.sub.15 alkyl phenol and unsulphurized metal
salts thereof.
Description
[0001] The present invention is concerned with a lubricating oil
composition suitable for use as a marine diesel cylinder lubricant.
In particular, the present invention is concerned with a marine
diesel cylinder lubricant that exhibits an increased rate of acid
neutralization.
[0002] Fuels used in marine diesel engines generally include a high
sulphur content, such as, for example, 2-3%. The exhaust gases
therefore include sulphur oxides which react with moisture to form
sulphuric acid which corrodes and wears components in the diesel
engine, such as cylinder liners and piston rings. Therefore, any
acid must be neutralized as quickly as possible.
[0003] EP 0 839 894A discloses a marine diesel cylinder lubricant
that exhibits a rapid neutralization rate. The lubricant includes
(A) at least one compound selected from the group consisting of
overbased sulphonates, phenates or salicylates of alkaline earth
metals, and (B) a bis-type succinic imide compound having an
absorption ratio, .alpha./.beta., of absorption peaks in an IR
spectrum of not more than 0.005, wherein .alpha. is the intensity
of an absorption peak at 1550.+-.10 cm.sup.-1 and .beta. is the
intensity of absorption peak at 1700.+-.cm.sup.-1.
[0004] EP 1 051 467B also discloses a marine diesel cylinder
lubricant that exhibits a rapid neutralization rate. The lubricant
includes 0.5 to 2.5% by weight of a succinimide dispersant, 3.5 to
10% by weight of an overbased sulphonate detergent and 11 to 24.5%
by weight of an overbased phenate detergent.
[0005] The aim of the present invention is to provide a lubricant
composition that exhibits an increased rate of acid
neutralization.
[0006] FIG. 1 shows graphically the results of Examples 1 through
3, representative of the present invention, and Comparative Example
4.
[0007] In accordance with the present invention there is provided a
lubricating oil composition including at least one sulphurized
overbased metal phenate detergent prepared from a C.sub.9-C.sub.15
alkyl phenol, at least one sulphurizing agent, at least one metal
and at least one overbasing agent; the detergent including less
than 6.0% by combined mass of unsulphurized C.sub.9-C.sub.15 alkyl
phenol and its unsulphurized metal salt.
[0008] The lubricating oil composition preferably has a total base
number (`TBN`) of more than 30, preferably more than 35, mgKOH/g,
as determined by ASTM D2896. The lubricating oil composition
preferably has a TBN of less than 100 mgKOH/g, as determined by
ASTM D2896.
[0009] In accordance with the present invention there is also
provided use to increase the rate of acid neutralization of a
lubricating oil composition of at least one sulphurized overbased
metal phenate detergent prepared from a C.sub.9-C.sub.15 alkyl
phenol, at least one sulphurizing agent, at least one metal and at
least one overbasing agent; the sulphurized overbased metal phenate
detergent including less than 6.0% by mass of unsulphurized
C.sub.9-C.sub.15 alkyl phenol and its unsulphurized metal salt.
[0010] In accordance with the present invention there is also
provided a method of increasing the rate of acid neutralization of
a lubricating oil composition, the method including the step of
adding to the lubricating oil composition at least one sulphurized
overbased metal phenate detergent prepared from a C.sub.9-C.sub.15
alkyl phenol, at least one sulphurizing agent, at least one metal
and at least one overbasing agent; the sulphurized overbased metal
phenate detergent including less than 6.0% by mass of unsulphurized
C.sub.9-C.sub.15 alkyl phenol and its unsulphurized metal salt.
[0011] By `alkyl phenol` we mean phenol having a linear or branched
alkyl group attached thereto.
[0012] The metal is preferably calcium.
[0013] The overbased phenate detergent is prepared from mono-, di-
and polysulphides of C.sub.9-C.sub.15 alkyl phenols. The
C.sub.9-C.sub.15 alkyl substituted phenols may contain one or more
C.sub.9-C.sub.15 alkyl groups per aromatic ring. Preferably, the
overbased phenate detergent is prepared from mono-, di- and
polysulphides of C.sub.10-C.sub.13 alkyl phenols.
[0014] The sulphurized C.sub.9-C.sub.15 alkyl phenols may be
represented by the general formula I:
##STR00001##
wherein R represents a C.sub.9-C.sub.15 alkyl radical, n is an
integer of 0 to 20, y is an integer of 0 to 4 and may be different
for each aromatic nucleus and x is an integer of from 1 to 7,
typically 1 to 4. The individual groups represented by R may be the
same or different and may contain from 9 to 15, preferably 10 to
13, carbon atoms. Preferably n is 0 to 4, y is 1 or 2 and may be
different for each aromatic nucleus and x is 1 to 4.
[0015] The sulphurized C.sub.9-C.sub.15 alkyl substituted phenols
may be mixtures of the above general formula and may include
un-sulphurized phenolic material. It is preferred that the level of
un-sulphurized phenolic material is kept to a minimum. The
sulphurized C.sub.9-C.sub.15 alkyl substituted phenols may contain
up to 15%, preferably up to 9%, by weight of un-sulphurized
phenolic material. One preferred group of sulphur zed
C.sub.9-C.sub.15 alkyl substituted phenols are those with a sulphur
content of between 4 and 16 mass %, preferably 4 to 14%, and most
preferably 6 to 12 mass %.
[0016] The sulphurized phenols, which will normally comprise a
mixture of different compounds, typically contain at least some
sulphur which is either free, or is only loosely bonded; the
sulphur thus being available to attack nitrile elastomeric seals
and is referred to as active sulphur. This active sulphur may be
present in the form of polysulphides, for example when x is three
or greater in formula I; in this form the active sulphur may be
present at levels which are typically up to 2 wt % or more.
[0017] The sulphurized C.sub.9-C.sub.15 alkyl phenols are prepared
by the reaction of C.sub.9-C.sub.15 alkyl phenols in the presence
of a sulphurizing agent; the sulphurizing agent being an agent
which introduces S.sub.X bridging groups between phenols where x is
1 to 7. Thus the reaction may be conducted with elemental sulphur
or a halide thereof such as sulphur monochloride or sulphur
dichloride. Preferably, sulphur monochloride is used.
[0018] The C.sub.9-C.sub.15 alkyl substituted phenols may be any
phenol of general formula II
##STR00002##
wherein R and y are as defined above. Mixtures of phenols of
general formula II may be used.
[0019] It is preferred that the oil soluble sulphurized phenol is
derived from sulphur monochloride and has low levels of chlorine
such as less than 1000 ppm of chlorine. Preferably the chlorine
content is 900 ppm or less e.g. 800 or less and most preferably 500
ppm or less.
[0020] It is preferred that the phenol is a mixture of phenols and
as such has an average molecular weight of between 210 and 310,
preferably between 230 and 290, and most preferably between 250 and
270. Most preferred mixtures are mixtures of para-substituted
monoalkylphenols. It is preferred that the phenols of general
formula II are not hindered phenols although they may be mixtures
of phenols which comprise a minor proportion, such as less than 25
wt % e.g. less than 10 wt %, of hindered phenol. By `hindered
phenols` is meant phenols in which all the ortho and para reactive
sites are substituted, or sterically hindered phenols in which,
either both ortho positions are substituted or only one ortho
position and the para position are substituted and, in either case,
the substituent is a tertiary alkyl group, e.g. t-butyl. It is
preferred that for a given mixture of mono and di-alkyl substituted
phenols, e.g. dodecyl substituted, that the mono-substituted phenol
is present in at least 80 wt % and preferably in the range 90 to 95
wt %. It is preferred that the mole ratio of phenol to sulphur
monochloride is 2 or greater and most preferably is 2.2 or
greater.
[0021] The level of sulphur, the required conversion of phenolic
material to keep the un-sulphurized material to a minimum and the
chlorine levels are linked. It is difficult to keep chlorine levels
low whilst increasing sulphur content and achieving the desired
conversion, because more chlorine containing starting material,
i.e. S.sub.2Cl.sub.2, is usually required to achieve these targets;
the task is to be able to achieve low chlorine whilst at the same
time not having a detrimental effect on the other two factors. It
is preferred that the reaction is carried out in the temperature
range of -15 or -10 to 150.degree. C., e.g. 20 to 150.degree. C.
and preferably 60 to 150.degree. C. It is most preferred that the
reaction is carried out at less than 110.degree. C.; the use of
reaction temperatures below 110.degree. C. with certain phenols
results in lower levels of chlorine. Typically the reaction
temperature is between 60 and 90.degree. C. Preferably the sulphur
monochloride is added to the reaction mixture at a rate of
4.times.10.sup.-4 to 15.sup.-4 cm.sup.3 min.sup.-1g.sup.-1 phenol.
If the reaction mixture is not adequately mixed during this
addition the chlorine content may increase. The resultant product
preferably has a sulphur content of at least 4%, e.g. between 4 and
16%, more preferably 4 to 14% and most preferably at least 6%, e.g.
7 to 12%. The process has the advantage of not requiring
complicated post reaction purification steps in order to reduce the
levels of chlorine in the intermediate product.
[0022] Olefins and acetylenic compounds may be used to remove
active sulphur from the sulphurized C.sub.9-C.sub.15 alkyl
substituted phenols.
[0023] Suitable olefins include mono-olefins, di-olefins,
tri-olefins or higher homologues. By suitable is meant olefins
which are capable of reacting with active sulphur and whose
properties are such that the excess of such olefins used may be
removed from the reaction mixture without resulting in significant
decomposition of the sulphurized phenol. Preferred olefins are
those with a boiling point of up to 200.degree. C. and most
preferably have a boiling point in the range of 150.degree. C. to
200.degree. C.
[0024] The mono-olefins may be unsubstituted aliphatic mono-olefins
meaning that they contain only carbon and hydrogen atoms, or they
may be substituted with one or more heteroatoms and/or heteroatom
containing groups e.g. hydroxyl, amino, cyano. An example of a
suitable cyano substituted mono-olefin is fumaronitrile. The
mono-olefins may also be substituted with aromatic functionality
as, for example, in styrene. The mono-olefins may contain for
example ester, amide, carboxylic acid, carboxylate, alkaryl,
amidine, sulphinyl, sulphonyl or other such groups. It is preferred
that the mono-olefins are aliphatic and are not substituted with
heteroatoms and/or heteroatom containing groups other than hydroxyl
or carboxylate groups. The mono-olefins may be branched or
non-branched.
[0025] The mono-olefin preferably has from 4 to 36 carbon atoms and
most preferably 8 to 20 carbon atoms. The mono-olefin may, for
example, be an .alpha.-olefin. Examples of .alpha.-olefins which
may be used include: 1-butene, 1-pentene, 1-hexene, 1-heptene,
1-octene, 1-nonene, 1-decene, 1-dodecene, 1-tridecene,
1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene,
1-octadecene, 1-nonadecene, 1-eicosene, 1-heneicosene, 1-docosene,
1-tetracosene, 1-pentacosene, 1-hexacosene, 1-octacosene, and
1-nonacosene. The .alpha.-olefin may be a mixture of
.alpha.-olefins such as the following commercially available
mixtures: C.sub.15-C.sub.18, C.sub.12-C.sub.16, C.sub.14-C.sub.16,
C.sub.14-C.sub.18, C.sub.16-C.sub.20, C.sub.22-C.sub.28, and
C.sub.30+ (Gulftene available from the Gulf Oil Company).
[0026] Another class of mono-olefins are those containing a
saturated alicyclic ring and one double bond, e.g. an exocyclic
double bond. The alicyclic ring preferably contains at least six
carbon atoms, and, advantageously, the alicyclic ring is
substituted by a methylene bridging group that forms a
four-membered ring with three of the ring carbon atoms. The
methylene carbon atom in such a bridging group may be substituted,
preferably by two methyl groups, e.g. as in .beta.-pinene. Other
examples of mono-olefins include .alpha.-pinene, methylene
cyclohexane, camphene, and methylene cyclopentane etc. and
unsaturated compounds such as the various derivatives of acrylic
acid such as acrylate, methacrylate and acrylamide derivatives.
[0027] An example of a suitable mono-olefin is the C.sub.12
tetramer of propylene. Other suitable mono-olefins include
oligomers of, for example, ethylene. Typically oligomeric olefins
are mixtures; therefore mixtures of oligomeric mono-olefins may be
used such as mixtures of propylene oligomers.
[0028] The di-olefins, tri-olefins and higher homologues may be any
such olefins which meet the above identified performance
requirement for the olefin. Preferred di-olefins, tri-olefins and
higher homologues are those selected from:
(a) an acyclic olefin having at least two double bonds adjacent
double bonds being separated by two saturated carbon atoms; or (b)
an olefin comprising an alicyclic ring, which ring comprises at
least eight carbon atoms and at least two double bonds, each double
bond being separated from the closest adjacent double bond(s) by
two saturated carbon atoms.
[0029] The preferred olefins of group (a) are unsubstituted or
substituted linear terpenes. Unsubstituted linear terpenes for use
in accordance with the invention may be represented by the formula
(C.sub.5H.sub.8).sub.n wherein n is at least 2, that is, a terpene
containing carbon and hydrogen atoms only. An example of an
unsubstituted linear terpene is squalene (in which n in the above
formula is 6). Possible substituents for linear terpenes to be used
are, for example, hydroxyl groups. Suitable substituted terpenes
include farnasol and geraniol with geraniol being preferred. Other
examples of suitable di-olefins include dicyclopentadiene,
dipentene, 1,3-cyclohexadiene, 1,5,-cyclooctadiene,
methylcyclopentadiene, limonene and 1,4-cyclohexadiene and
polybutadiene etc.
[0030] If desired, the group (b) olefins may contain at least three
double bonds, each end of each double bond being separated from
each adjacent double bond by two saturated carbon atoms. An example
of a suitable group (b) olefin having three double bonds is
1,5,9-cyclododecatriene. An example of another tri-olefin is
cycloheptatriene.
[0031] The acetylenic compounds are compounds which are capable of
reacting with active sulphur and whose properties are such that the
excess of such compounds may be removed from the reaction mixture
without resulting in significant decomposition of the sulphurized
phenol. An example of a suitable acetylene material is phenyl
acetylene.
[0032] Olefins are preferred to acetylenic compounds,
[0033] More than one olefin may of course be used if desired. Where
two or more olefins are used, these need not be compounds from the
same group. Thus, for example, mixtures of mono and diolefins may
be used although this is not preferred.
[0034] The olefin or acetylenic compound and active
sulphur-containing sulphurized phenol may be added in any order.
Thus, for example, the olefin or acetylenic compound may be
introduced into a vessel already containing the sulphurized phenol
or vice versa, or the two materials may be introduced
simultaneously into the vessel. This process may be carried out in
a suitable solvent for the reactants and/or products. This is a
solvent which does not cause problems in removal which effect
stability of the product. An example of a suitable solvent which
may be used is SN150 basestock. In some instances the olefin when
used in a sufficient amount may act as a solvent for the
reaction.
[0035] The mass ratio of sulphurized phenol to olefin or acetylenic
compound is such that the olefin or acetylenic compound is always
in excess of that required to react with the active sulphur present
in the intermediate. The exact levels will depend on the nature of
the olefin or acetylenic compound, i.e. whether or not, for
example, it is a mono, di or tri olefin, its molecular weight and
the molecular weight of the sulphurized phenol used, its level of
sulphur and level of active sulphur. For example, when the olefin
is C.sub.12 propylene tetramer the ratio is preferably in the range
1.3:1 to 9:1.
[0036] It is preferred that the reaction between the sulphurized
phenol and the olefin or acetylenic compound is carried out at an
elevated temperature of greater that 120.degree. C. and, most
preferably between 120.degree. C. to 250.degree. C., and for 0.5 to
60 hours.
[0037] Substantially all of the unreacted olefin or acetylenic
compound should be removed preferably by means of vacuum
distillation, post reaction, or other separation methods. The exact
method used will depend on the nature of the olefin or acetylenic
compound used. In some circumstances the unreacted olefin or
acetylenic compound may be removed by simply applying a vacuum to
the reaction vessel or may require the use of applied heating to
elevate the temperature of the reaction mixture. Preferably the
unreacted material is removed by means of vacuum distillation and
where necessary with the use of heating. Other material, such as
volatile material when vacuum distillation is used, may be removed
at the same time as the unreacted olefin or acetylenic compound. By
`substantially all the unreacted olefin or acetylenic compound` is
meant that proportion which may be removed by the use of such
techniques as, for example, vacuum distillation. Typically there
will be less than 3 wt % of unreacted olefin or acetylenic compound
remaining in the product and preferably between 0 to 3 wt % and
most preferably 0.5 wt % or less. This residual material may
comprise as a major proportion the higher molecular weight
fractions present in the original olefin composition or mixture
used. For example, in the case of the olefin being a propylene
tetramer, which is typically a mixture of olefins, residual
material after removal of excess olefin may comprise a high
proportion of, for example, pentamer and higher homologues of
propylene.
[0038] It has been found that removal of substantially all the
unreacted olefin or acetylenic compound is required so that
lubricating oil compositions comprising olefin or acetylenic
compound reacted additives achieve acceptable performance in the
Panel Coker test. This is an industry standard bench test which is
used to screen additives in lubricating oil formulations to
evaluate their efficacy as, for example, antioxidants and/or their
ability to prevent deposition of carbonaceous deposits by
maintaining such deposits in a dispersed form in the oil. If the
excess olefin or acetylenic compound is not removed inferior Panel
Coker performance of the oil is observed. This is a particular
problem with di-olefins.
[0039] On completion of the reaction between sulphur monochloride
and the phenol, the temperature of the reaction mixture is
increased to the olefin or acetylenic compound reaction temperature
and the reaction carried out. This increase in temperature may be
achieved by means of a ramped temperature increase to the reaction
temperature. The olefin or acetylenic compound may be added to the
intermediate reaction mixture before, during or after the
temperature increase.
[0040] A catalyst may be used for the reaction between the olefin
or acetylenic compound and the sulphurized phenol. Suitable
catalysts include sulphurisation catalysts and nitrogen bases. The
preferred catalysts are nitrogen bases. Suitable nitrogen bases
include nitrogen-containing ashless dispersants which are
commercially available materials such as Mannich bases and the
reaction products of hydrocarbyl acylating agents with amines, in
particular polyisobutenyl succinimides may be used; these may be
prepared by any of the conventional routes. It is preferred to use
a polyisobutenyl succinimide in which the polyisobutenyl succinic
anhydride is prepared using the so-called thermal process in which
polyisobutene is reacted directly with maleic anhydride, without
the use of chlorine, before reaction with the amine to produce the
final dispersant. Other suitable nitrogen bases include simple
amines such as, for example, mono-, di-, and tri-butylamines,
polyamines such as, for example, diethylenetriamine (DETA),
triethylenetetramine (TETA) and tetraethylenepentamine (TEPA),
cyclic amines for example morpholines and aromatic amines such as
commercial diphenylamines. A particularly suitable amine is
n-octylamine. It has also surprisingly been found that nitrile seal
compatibility improves with the use of increasing levels of
catalyst to prepare the additives of the present invention.
[0041] The reaction with olefin or acetylenic compound has the
benefit of reducing the level of chlorine in sulphurized
compounds.
[0042] The sulphurized C.sub.9-C.sub.15 alkyl substituted phenols
are used to prepare the overbased metal phenates by reaction with
alkali or alkaline earth metal salts or compounds. The overbased
metal phenates may also have low levels of chlorine e.g. less than
1000 ppm. The overbased metal phenates comprise neutralized
detergent as the outer layer of a metal base (e.g. carbonate)
micelle. Such overbased metal phenates may have a TBN (total base
number as determined by ASTM D 2896) of 50 or greater, preferably
100 or greater, more preferably 150 or greater, and typically of
from 250 to 450 or more. The metals are in particular the alkali or
alkaline earth metals, e.g., sodium potassium, lithium, calcium,
and magnesium. The most commonly used metals are calcium and
magnesium and mixtures of calcium and/or magnesium with sodium.
[0043] The overbased phenates may include at least one further
surfactant such as, for example, a sulphonic acid or an aliphatic
carboxylic acid such as, for example, stearic acid.
[0044] Sulphonic acids are typically obtained by sulphonation of
hydrocarbyl-substituted, especially alkyl-substituted, aromatic
hydrocarbons, for example, those obtained from the fractionation of
petroleum by distillation and/or extraction, or by the alkylation
of aromatic hydrocarbons. Examples include those obtained by
alkylating benzene, toluene, xylene, naphthalene, biphenyl or their
halogen derivatives, for example, chlorobenzene, chlorotoluene or
chloronaphthalene. Alkylation of aromatic hydrocarbons may be
carried out in the presence of a catalyst with alkylating agents
having from about 3 to more than 100 carbon atoms, such as, for
example, haloparaffins, olefins that may be obtained by
dehydrogenation of paraffins, and polyolefins, for example,
polymers of ethylene, propylene, and/or butene. The alkylaryl
sulphonic acids usually contain from about 7 to about 100 or more
carbon atoms. They preferably contain from about 16 to about 80
carbon atoms, or 12 to 40 carbon atoms, per alkyl-substituted
aromatic moiety, depending on the source from which they are
obtained.
[0045] Another type of sulphonic acid which may be used comprises
alkyl phenol sulphonic acids. Such sulphonic acids can be
sulphurized. Whether sulphurized or non-sulphurized these sulphonic
acids are believed to have surfactant properties comparable to
those of sulphonic acids, rather than surfactant properties
comparable to those of phenols.
[0046] Sulphonic acids suitable for use also include alkyl
sulphonic acids. In such compounds the alkyl group suitably
contains 9 to 100 carbon atoms, advantageously 12 to 80 carbon
atoms, especially 16 to 60 carbon atoms. Carboxylic acids which may
be used include mono- and dicarboxylic acids. Preferred
monocarboxylic acids are those containing 1 to 30 carbon atoms,
especially 8 to 24 carbon atoms. Examples of monocarboxylic acids
are iso-octanoic acid, stearic acid, oleic acid, palmitic acid and
behenic acid. Iso-octanoic acid may, if desired, be used in the
form of the mixture of C.sub.8 acid isomers sold by Exxon Chemical
under the trade name "Cekanoic", Other suitable acids are those
with tertiary substitution at the .alpha.-carbon atom and
dicarboxylic acids with more than 2 carbon atoms separating the
carboxylic groups. Further, dicarboxylic acids with more than 35
carbon atoms, for example, 36 to 100 carbon atoms, are also
suitable. Unsaturated carboxylic acids can be sulphurized.
[0047] In another aspect of the invention, the carboxylic
acid/derivative, if used, has 8 to 11 carbon atoms in the
carboxylic-containing moiety.
[0048] In a further aspect of the invention, where a carboxylic
acid/derivative is used, this is not a monocarboxylic
acid/derivative with more than 11 carbon atoms in the
carboxylic-containing moiety. In another aspect, the carboxylic
acid/derivative is not a dicarboxylic acid/derivative with more
than 11 carbon atoms in the carboxylic-containing moiety. In a
further aspect, the carboxylic acid/derivative is not a
polycarboxylic acid/derivative with more than 11 carbon atoms in
the carboxylic-containing moiety. In another aspect, a carboxylic
acid surfactant is not a hydrocarbyl-substituted succinic acid or a
derivative thereof.
[0049] Examples of other surfactants which may be used include the
following compounds, and derivatives thereof: naphthenic acids,
especially naphthenic acids containing one or more alkyl groups,
dialkylphosphonic acids, dialkylthiophosphonic acids, and
dialkyldithiophosphoric acids, high molecular weight (preferably
ethoxylated) alcohols, dithiocarbamic acids, thiophosphines, and
dispersants, Surfactants of these types are well known to those
skilled in the art.
[0050] Metal salts of sulphurized phenols are prepared by reaction
with an appropriate metal compound such as an oxide or hydroxide
and neutral or overbased products may be obtained by methods well
known in the art.
[0051] Examples of suitable overbasing agents are carbon dioxide, a
source of boron, for example, boric acid, sulphur dioxide, hydrogen
sulphide, and ammonia. Preferred overbasing agents are carbon
dioxide or boric acid, or a mixture of the two. The most preferred
overbasing agent is carbon dioxide and, for convenience, the
treatment with an overbasing agent will in general be referred to
as "carbonation". Unless the context clearly requires otherwise, it
will be understood that references herein to carbonation include
references to treatment with other overbasing agents.
[0052] Advantageously, on completion of the carbonation step, part
of the basic calcium compound remains uncarbonated. Advantageously,
up to 15 mass % of the basic calcium compound remains uncarbonated,
especially up to 11 mass %.
[0053] Carbonation is effected at less than 100.degree. C.
Typically the carbonation is effected at least 15.degree. C.,
preferably at least 25.degree. C. Advantageously, carbonation is
carried out at less than 80.degree. C., more advantageously less
than 60.degree. C. preferably at most 50.degree. C., more
preferably at most 40.degree. C., and especially at most 35.degree.
C. Advantageously, the temperature is maintained substantially
constant during the, or each, carbonation step, with only minor
fluctuations. Where there is more than one carbonation step, both
or all carbonation steps are preferably carried out at
substantially the same temperature, although different temperatures
may be used, if desired, provided that each step is carried out at
less than 100.degree. C.
[0054] Carbonation may be effected at atmospheric,
super-atmospheric or sub-atmospheric pressures. Preferably,
carbonation is carried out at atmospheric pressure.
[0055] Advantageously, there is a first carbonation step that is
followed by a "heat-soaking" step in which the mixture is
maintained, without addition of any further chemical reagents, in a
selected temperature range (or at a selected temperature), which is
normally higher than the temperature at which carbonation is
effected, for a period before any further processing steps are
carried out. The mixture is normally stirred during heat-soaking.
Typically, heat-soaking may be carried out for a period of at least
30 minutes, advantageously at least 45 minutes, preferably at least
60 minutes, especially at least 90 minutes. Temperatures at which
heat-soaking may be carried out are typically in the range of from
15.degree. C. to just below the reflux temperature of the reaction
mixture, preferably 25.degree. C. to 60.degree. C.: the temperature
should be such that substantially no materials (for example,
solvents) are removed from the system during the heat-soaking step.
We have found that heat-soaking has the effect of assisting product
stabilization, dissolution of solids, and filterability.
[0056] Preferably, following the first carbonation step (and the
heat-soaking step, if used), a further quantity of basic calcium
compound is added to the mixture and the mixture is again
carbonated, the second carbonation step advantageously being
followed by a heat-soaking step.
[0057] Basic calcium compounds for use in manufacture of the
overbased detergents include calcium: oxide, hydroxide, alkoxides,
and carboxylates. Calcium oxide and, more especially, hydroxide are
preferably used. A mixture of basic compounds may be used, if
desired.
[0058] The mixture to be overbased by the overbasing agents should
normally contain water, and may also contain one or more solvents,
promoters or other substances commonly used in overbasing
processes.
[0059] Examples of suitable solvents are aromatic solvents, for
example, benzene, alkyl-substituted benzenes, for example, toluene
or xylene, halogen-substituted benzenes, and lower alcohols (with
up to 8 carbon atoms). Preferred solvents are toluene and methanol.
The amount of toluene used is advantageously such that the
percentage by mass of toluene, based on the calcium overbased
detergent (excluding oil) is at least 1.5, preferably at least 15,
more preferably at least 45, especially at least 60, more
especially at least 90. For practical/economic reasons, the said
percentage of toluene is typically at most 1200, advantageously at
most 600, preferably at most 500, especially at most 150. The
amount of methanol used is advantageously such that the percentage
by mass of methanol, based on the calcium detergent (excluding oil)
is at least 1.5, preferably at least 15, more preferably at least
30, especially at least 45, more especially at least 50. For
practical/economic reasons, the said percentage of methanol (as
solvent) is typically at most 800, advantageously at most 400,
preferably at most 200, especially at most 100. The above
percentages apply whether the toluene and methanol are used
together or separately.
[0060] Examples of suitable promoters are lower alcohols (with up
to 8 carbon atoms) and water. Preferred promoters for use in
accordance with the invention are methanol and water. The amount of
methanol used is advantageously such that the percentage by mass of
methanol, based on the initial charge of basic calcium compound,
for example, calcium hydroxide (that is, excluding any basic
calcium compound added in a second or subsequent step) is at least
6, preferably at least 60, more preferably at least 120, especially
at least 180, more especially at least 210. For practical/economic
reasons, the said percentage of methanol (as promoter) is typically
at most 3200, advantageously at most 1600, preferably at most 800,
especially at most 400. The amount of water in the initial reaction
mixture (prior to treatment with the overbasing agent) is
advantageously such that the percentage by mass of water, based on
the initial charge of basic calcium compound(s), for example,
calcium hydroxide, (that is, excluding any basic calcium
compound(s) added in a second or subsequent step) is at least 0.1,
preferably at least 1, more preferably at least 3, especially at
least 6, more especially at least 12, particularly at least 20. For
practical/economic reasons, the said percentage of water is
typically at most 320, advantageously at most 160, preferably at
most 80, especially at most 40. If reactants used are not
anhydrous, the proportion of water in the reaction mixture should
take account of any water in the components and also water formed
by neutralization of the surfactants. In particular, allowance must
be made for any water present in the surfactants themselves.
[0061] Advantageously, the reaction medium comprises methanol,
water (at least part of which may be generated during salt
formation), and toluene.
[0062] If desired, low molecular weight carboxylic acids (with 1 to
about 7 carbon atoms), for example, formic acid, inorganic halides,
or ammonium compounds may be used to facilitate carbonation, to
improve filterability, or as viscosity agents for overbased
detergents. The process does not, however, require the use of an
inorganic halide or ammonium salt catalyst, for example, ammonium
salts of lower carboxylic acids or of alcohols, and the overbased
detergents produced are thus preferably free from groups derived
from such a halide or ammonium catalyst. (Where an inorganic halide
or ammonium salt is used in an overbasing process the catalyst will
normally be present in the final overbased detergent.)
[0063] Oil-soluble, dissolvable, or stably dispersible as that
terminology is used herein does not necessarily indicate that the
additives or intermediates are soluble, dissolvable, miscible, or
capable of being suspended in oil in all proportions. It does mean,
however, that they are, for instance, soluble or stably dispersible
in oil to an extent sufficient to exert their intended effect in
the environment in which the oil is employed. Moreover, the
additional incorporation of other additives may also permit
incorporation of higher levels of a particular additive or
intermediate, if desired.
[0064] The overbased phenates can be incorporated into base oil in
any convenient way. Thus, they can be added directly to the oil by
dispersing or by dissolving them in the oil at the desired level of
concentration, optionally with the aid of a suitable solvent such
as, for example, toluene, cyclohexane, or tetrahydrofuran. In some
cases blending may be effected at room temperature: in other cases
elevated temperatures are advantageous such as up to 100.degree.
C.
[0065] Base oils include those suitable for use in marine diesel
engines.
[0066] Synthetic base oils include alkyl esters of dicarboxylic
acids, polyglycols and alcohols: poly-.alpha.-olefins, polybutenes,
alkyl benzenes, organic esters of phosphoric acids and polysilicone
oils.
[0067] Natural base oils include mineral lubricating oils which may
vary widely as to their crude source, for example, as to whether
they are paraffinic, naphthenic, mixed, or paraffinic-naphthenic,
as well as to the method used in their production, for example,
distillation range, straight run or cracked, hydrorefined, solvent
extracted and the like.
[0068] More specifically, natural lubricating oil base stocks which
can be used may be straight mineral lubricating oil or distillates
derived from paraffinic, naphthenic, asphaltic, or mixed base crude
oils. Alternatively, if desired, various blended oils may be
employed as well as residual oils, particularly those from which
asphaltic constituents have been removed. The oils may be refined
by any suitable method, for example, using acid, alkali, and/or
clay or other agents such, for example, as aluminium chloride, or
they may be extracted oils produced, for example, by solvent
extraction with solvents, for example, phenol, sulphur dioxide,
furfural, dichlorodiethylether, nitrobenzene, or
crotonaldehyde.
[0069] The lubricating oil base stock conveniently has a viscosity
of about 2.5 to about 12 cSt or mm.sup.2/sec and preferably about
3.5 to about 9 cSt or mm.sup.2/sec at 100.degree. C.
[0070] Additional additives may be incorporated into the
lubricating oil composition to enable it to meet particular
requirements. Examples of additives which may be included in
lubricating oil compositions are further detergents, dispersants,
anti-wear agents and pour point depressants.
[0071] The ashless dispersants comprise an oil soluble polymeric
hydrocarbon backbone having functional groups that are capable of
associating with particles to be dispersed. Typically, the
dispersants comprise amine, alcohol, amide, or ester polar moieties
attached to the polymer backbone often via a bridging group. The
ashless dispersant may be, for example, selected from oil soluble
salts, esters, amino-esters, amides, imides, and oxazolines of long
chain hydrocarbon substituted mono and dicarboxylic acids or their
anhydrides; thiocarboxylate derivatives of long chain hydrocarbons;
long chain aliphatic hydrocarbons having a polyamine attached
directly thereto; and Mannich condensation products formed by
condensing a long chain substituted phenol with formaldehyde and
polyalkylene polyamine.
[0072] The oil soluble polymeric hydrocarbon backbone is typically
an olefin polymer or polyene, especially polymers comprising a
major molar amount (i.e., greater than 50 mole %) of a C.sub.2 to
C.sub.18 olefin (e.g., ethylene, propylene, butylene, isobutylene,
pentene, octene-1, styrene), and typically a C.sub.2 to C.sub.5
olefin. The oil soluble polymeric hydrocarbon backbone may be a
homopolymer (e.g., polypropylene or polyisobutylene) or a copolymer
of two or more of such olefins (e.g., copolymers of ethylene and an
alpha-olefin such as propylene or butylene, or copolymers of two
different alpha-olefins). Other copolymers include those in which a
minor molar amount of the copolymer monomers, e.g. 1 to 10 mole %,
is an .alpha.,.omega.-diene, such as a C.sub.3 to C.sub.22
non-conjugated diolefin (e.g. a copolymer of isobutylene and
butadiene, or a copolymer of ethylene, propylene and 1,4-hexadiene
or 5-ethylidene-2-norbornene). Atactic propylene oligomer typically
having Mn of from 700 to 5000 may also be used, as described in
EP-A-490454, as well as heteropolymers such as polyepoxides.
[0073] One preferred class of olefin polymers is polybutenes and
specifically polyisobutenes (PIB) or poly-n-butenes, such as may be
prepared by polymerization of a C.sub.4 refinery stream. Other
preferred classes of olefin polymers are ethylene alpha-olefin
(EAO) copolymers and alpha-olefin homo- and copolymers having in
each case a high degree (e.g. >30%) of terminal vinylidene
unsaturation. That is, the polymer has the following structure:
##STR00003##
wherein P is the polymer chain and R is a C.sub.1-C.sub.18 alkyl
group, typically methyl or ethyl. Preferably the polymers will have
at least 50% of the polymer chains with terminal vinylidene
unsaturation. EAO copolymers of this type preferably contain 1 to
50 wt % ethylene, and more preferably 5 to 48 wt % ethylene. Such
polymers may contain more than one alpha-olefin and may contain one
or more C.sub.3 to C.sub.22 diolefins. Also usable are mixtures of
EAO's of varying ethylene content. Different polymer types, e.g.
EAO and PIB, may also be mixed or blended, as well as polymers
differing in Mn; components derived from these also may be mixed or
blended.
[0074] Suitable olefin polymers and copolymers may be prepared by
various catalytic polymerization processes. In one method,
hydrocarbon feed streams, typically C.sub.3-C.sub.5 monomers, are
cationically polymerized in the presence of a Lewis acid catalyst
and, optionally, a catalytic promoter, e.g., an organoaluminum
catalyst such as ethylaluminum dichloride and an optional promoter
such as HCl. Most commonly, polyisobutylene polymers are derived
from Raffinate I refinery feedstreams. Various reactor
configurations can be utilized, e.g. tubular or stirred tank
reactors, as well as fixed bed catalyst systems in addition to
homogeneous catalysts. Such polymerization processes and catalysts
are described, e.g., in U.S. Pat. Nos. 4,935,576; 4,952,739;
4,982,045; and UK-A 2,001,662.
[0075] Conventional Ziegler-Natta polymerization processes may also
be employed to provide olefin polymers suitable for use in
preparing dispersants and other additives. However, preferred
polymers may be prepared by polymerising the appropriate monomers
in the presence of a particular type of Ziegler-Natta catalyst
system comprising at least one metallocene (e.g., a
cyclopentadienyl-transition metal compound) and, preferably, a
cocatalyst or an activator, e.g., an alumoxane compound or an
ionising ionic activator such as tri (n-butyl) ammonium tetra
(pentafluorophenyl) boron.
[0076] Metallocene catalysts are, for example, bulky ligand
transition metal compounds of the formula:
[L].sub.mM[A].sub.n
where L is a bulky ligand; A is a leaving group, M is a transition
metal and m and n are such that the total ligand valency
corresponds to the transition metal valency. Preferably the
catalyst is four co-ordinate such that the compound is ionizable to
a 1.sup.+ valency state. The ligands L and A may be bridged to each
other, and if two ligands A and/or L are present, they may be
bridged. The metallocene compound may be a full sandwich compound
having two or more ligands L which may be cyclopentadienyl ligands
or cyclopentadienyl derived ligands, or they may be half sandwich
compounds having one such ligand L. The ligand may be mono- or
polynuclear or any other ligand capable of .eta.-5 bonding to the
transition metal.
[0077] One or more of the ligands may .pi.-bond to the transition
metal atom, which may be a Group 4, 5 or 6 transition metal and/or
a lanthanide or actinide transition metal, with zirconium, titanium
and hafnium being particularly preferred.
[0078] The ligands may be substituted or unsubstituted, and mono-,
di-, tri, tetra- and penta-substitution of the cyclopentadienyl
ring is possible. Optionally the substituent(s) may act as one or
more bridge between the ligands and/or leaving groups and/or
transition metal. Such bridges typically comprise one or more of a
carbon, germanium, silicon, phosphorus or nitrogen atom-containing
radical, and preferably the bridge places a one atom link between
the entities being bridged, although that atom may and often does
carry other substituents.
[0079] The metallocene may also contain a further displaceable
ligand, preferably displaced by a cocatalyst--a leaving group--that
is usually selected from a wide variety of hydrocarbyl groups and
halogens.
[0080] Such polymerizations, catalysts, and cocatalysts or
activators are described, for example, in U.S. Pat. Nos. 4,530,914;
4,665,208; 4,808,561; 4,871,705; 4,897,455; 4,937,299; 4,952,716;
5,017,714; 5,055,438; 5,057,475; 5,064,802; 5,096,867; 5,120,867;
5,124,418; 5,153,157; 5,198,401; 5,227,440; 5,241,025;
EP-A-129,368; 277,003; 277,004; 420436; 520,732; WO91/04257;
92/00333; 93/08199 and 93/08221; and 94/07928.
[0081] The oil soluble polymeric hydrocarbon backbone will usually
have a number average molecular weight ( Mn) within the range of
from 300 to 20,000. The Mn of the polymer backbone is preferably
within the range of 500 to 10,000, more preferably 700 to 5,000,
where its use is to prepare a component having the primary function
of dispersancy. Polymers of both relatively low molecular weight
(e.g. Mn=500 to 1500) and relatively high molecular weight (e.g.
Mn=1500 to 5,000 or greater) are useful to make dispersants.
Particularly useful olefin polymers for use in dispersants have Mn
within the range of from 1500 to 3000. Where the oil additive
component is also intended to have a viscosity modifying effect, it
is desirable to use a polymer of higher molecular weight, typically
with Mn of from 2,000 to 20,000; and if the component is intended
to function primarily as a viscosity modifier then the molecular
weight may be even higher, e.g., Mn of from 20,000 up to 500,000 or
greater. Furthermore, the olefin polymers used to prepare
dispersants preferably have approximately one double bond per
polymer chain, preferably as a terminal double bond.
[0082] Polymer molecular weight, specifically Mn, can be determined
by various known techniques. One convenient method is gel
permeation chromatography (GPC), which additionally provides
molecular weight distribution information (see W. W. Yau, J. J.
Kirkland and D. D. Bly, "Modern Size Exclusion Liquid
Chromatography", John Wiley and Sons, New York, 1979). Another
useful method, particularly for lower molecular weight polymers, is
vapour pressure osmometry (see, e.g., ASTM D3592). The oil soluble
polymeric hydrocarbon backbone may be functionalized to incorporate
a functional group into the backbone of the polymer, or as one or
more groups pendant from the polymer backbone. The functional group
typically will be polar and contain one or more hetero atoms such
as P, O, S, N, halogen, or boron. It can be attached to a saturated
hydrocarbon part of the oil soluble polymeric hydrocarbon backbone
via substitution reactions or to an olefinic portion via addition
or cycloaddition reactions. Alternatively, the functional group can
be incorporated into the polymer in conjunction with oxidation or
cleavage of the polymer chain end (e.g. as in ozonolysis),
[0083] Useful functionalization reactions include: halogenation of
the polymer at an olefinic bond and subsequent reaction of the
halogenated polymer with an ethylenically unsaturated functional
compound (e.g. maleation where the polymer is reacted with maleic
acid or anhydride); reaction of the polymer with an unsaturated
functional compound by the "ene" reaction absent halogenation;
reaction of the polymer with at least one phenol group (this
permits derivatization in a Mannich base-type condensation);
reaction of the polymer at a point of unsaturation with carbon
monoxide using a Koch-type reaction to introduce a carbonyl group
in an iso or neo position; reaction of the polymer with the
functionalizing compound by free radical addition using a free
radical catalyst; reaction with a thiocarboxylic acid derivative;
and reaction of the polymer by air oxidation methods, epoxidation,
chloroamination, or ozonolysis. It is preferred that the polymer is
not halogenated.
[0084] The functionalized oil soluble polymeric hydrocarbon
backbone is then further derivatized with a nucleophilic reactant
such as an amine, amino-alcohol, alcohol, metal compound or mixture
thereof to form a corresponding derivative.
[0085] Useful amine compounds for derivatizing functionalized
polymers comprise at least one amine and can comprise one or more
additional amine or other reactive or polar groups. These amines
may be hydrocarbyl amines or may be predominantly hydrocarbyl
amines in which the hydrocarbyl group includes other groups, e.g.
hydroxyl groups, alkoxy groups, amide groups, nitriles, imidazoline
groups, and the like. Particularly useful amine compounds include
mono- and polyamines, e.g. polyalkylene and polyoxyalklene
polyamines of about 2 to 60) conveniently 2 to 40 (e.g., 3 to 20),
total carbon atoms and about 1 to 12, conveniently 3 to 12, and
preferably 3 to 9 nitrogen atoms in the molecule. Mixtures of amine
compounds may advantageously be used such as those prepared by
reaction of alkylene dihalide with ammonia. Preferred amines are
aliphatic saturated amines, including, e.g., 1,2-diaminoethane;
1,3-diamino propane; 1,4-diaminobutane; 1,6-diaminohexane;
polyethylene amines such as diethylene triamine; triethylene
tetramine; tetraethylene pentamine; and polypropyleneamines such as
1,2-propylene diamine; and di-(1,2-propylene)triamine.
[0086] Other useful amine compounds include: alicyclic diamines
such as 1,4-di(aminomethyl)cyclohexane, and heterocyclic nitrogen
compounds such as imidazolines. A particularly useful class of
amines are the polyamido and related amido-amines as disclosed in
U.S. Pat. Nos. 4,857,217; 4,956,107; 4,963,275; and 5,229,022. Also
usable is tris(hydroxymethyl)amino methane (THAM) as described in
U.S. Pat. Nos. 4,102,798; 4,113,639; 4,116,876; and UK 989,409.
Dendrimers, star-like amines, and comb-structure amines may also be
used. Similarly, one may use the condensed amines disclosed in U.S.
Pat. No. 5,053,152. The functionalized polymer is reacted with the
amine compound according to conventional techniques as described in
EP-A 208,560; U.S. Pat. No. 4,234,435 and U.S. Pat. No.
5,229,022.
[0087] The functionalized oil soluble polymeric hydrocarbon
backbones also may be derivatized with hydroxy compounds such as
monohydric and polyhydric alcohols or with aromatic compounds such
as phenols and naphthols. Polyhydric alcohols are preferred, e.g.
alkylene glycols in which the alkylene radical contains from 2 to 8
carbon atoms. Other useful polyhydric alcohols include glycerol,
mono-oleate of glycerol, monostearate of glycerol, monomethyl ether
of glycerol, pentaerythritol, dipentaerythritol, and mixtures
thereof. An ester dispersant may also be derived from unsaturated
alcohols such as allyl alcohol, cinnamyl alcohol, propargyl
alcohol, 1-cyclohexane-3-ol, and oleyl alcohol, Still other classes
of the alcohols capable of yielding ashless dispersants comprise
the ether-alcohols and including, for example, the oxy-alkylene,
oxy-arylene. They are exemplified by ether-alcohols having up to
150 oxy-alkylene radicals in which the alkylene radical contains
from 1 to 8 carbon atoms. The ester dispersants may be di-esters of
succinic acids or acidic esters, i.e. partially esterified succinic
acids; as well as partially esterified polyhydric alcohols or
phenols, i.e. esters having free alcohols or phenolic hydroxyl
radicals. An ester dispersant may be prepared by one of several
known methods as illustrated, for example, in U.S. Pat. No.
3,381,022.
[0088] A preferred group of ashless dispersants includes those
derived from polyisobutylene substituted with succinic anhydride
groups and reacted with polyethylene amines (e.g. tetraethylene
pentamine, pentaethylene (di)pentamine, polyoxypropylene diamine)
aminoalcohols such as trismethylolaminomethane and optionally
additional reactants such as alcohols and reactive metals, e.g.
pentaerythritol, and combinations thereof). Also useful are
dispersants wherein a polyamine is attached directly to the long
chain aliphatic hydrocarbon as shown in U.S. Pat. Nos. 3,275,554
and 3,565,804 where a halogen group on a halogenated hydrocarbon is
displaced with various alkylene polyamines.
[0089] Another class of ashless dispersants comprises Mannich base
condensation products. Generally, these are prepared by condensing
about one mole of an alkyl-substituted mono- or polyhydroxy benzene
with about 1 to 2.5 moles of carbonyl compounds (e.g. formaldehyde
and paraformaldehyde) and about 0.5 to 2 moles polyalkylene
polyamine as disclosed, for example, in U.S. Pat. No. 3,442,808.
Such Mannich condensation products may include a long chain, high
molecular weight hydrocarbon (e.g. Mn of 1,500 or greater) on the
benzene group or may be reacted with a compound containing such a
hydrocarbon, for example, polyalkenyl succinic anhydride, as shown
in U.S. Pat. No. 3,442,808.
[0090] Examples of functionalized and/or derivatized olefin
polymers based on polymers synthesized using metallocene catalyst
systems are described in U.S. Pat. Nos. 5,128,056; 5,151,204;
5,200,103; 5,225,092; 5,266,223; EP-A-440,506; 513,157; 513,211.
The functionalization and/or derivatizations and/or post treatments
described in the following patents may also be adapted to
functionalize and/or derivatize the preferred polymers described
above: U.S. Pat. Nos. 3,087,936; 3,254,025; 3,275,554; 3,442,808,
and 3,565,804.
[0091] The dispersant can be further post-treated by a variety of
conventional post treatments such as boration, as generally taught
in U.S. Pat. Nos. 3,087,936 and 3,254,025. This is readily
accomplished by treating an acyl nitrogen-containing dispersant
with a boron compound selected from the group consisting of boron
oxide, boron halides, boron acids and esters of boron acids, in an
amount to provide from about 0.1 atomic proportion of boron for
each mole of the acylated nitrogen composition to about 20 atomic
proportions of boron for each atomic proportion of nitrogen of the
acylated nitrogen composition. Usefully the dispersants contain
from about 0.05 to 2.0 wt. %, e.g. 0.05 to 0.7 wt. %, boron based
on the total weight of the borated acyl nitrogen compound. The
boron, which appears be in the product as dehydrated boric acid
polymers (primarily (HBO.sub.2).sub.3), is believed to attach to
the dispersant imides and diimides as amine salts, e.g. the
metaborate salt of the diimide. Boration is readily carried out by
adding from about 0.05 to 4, e.g. 1 to 3, wt. % (based on the
weight of acyl nitrogen compound) of a boron compound, preferably
boric acid, usually as a slurry, to the acyl nitrogen compound and
heating with stirring at from 135.degree. to 190.degree. C., e.g.
140.degree.-170.degree. C., for from 1 to 5 hours followed by
nitrogen stripping. Alternatively, the boron treatment can be
carried out by adding boric acid to a hot reaction mixture of the
dicarboxylic acid material and amine while removing water.
[0092] Metal-containing or ash-forming detergents function both as
detergents to reduce or remove deposits and as acid neutralisers or
rust inhibitors, thereby reducing wear and corrosion and extending
engine life. Detergents generally comprise a polar head with a long
hydrophobic tail, with the polar head comprising a metal salt of an
acidic organic compound. The salts may contain a substantially
stoichiometric amount of the metal in which case they are usually
described as normal or neutral salts, and would typically have a
total base number or TBN (as may be measured by ASTM D2896) of from
0 to 80. It is possible to include large amounts of a metal base by
reacting an excess of a metal compound such as an oxide or
hydroxide with an acidic gas such as carbon dioxide. The resulting
overbased detergent comprises neutralized detergent as the outer
layer of a metal base (e.g. carbonate) micelle. Such overbased
detergents may have a TBN of 150 or greater, and typically of from
250 to 450 or more.
[0093] Detergents that may be used include oil-soluble neutral and
overbased sulphonates, phenates, sulphurized phenates,
thiophosphonates, salicylates, and naphthenates and other
oil-soluble carboxylates of a metal, particularly the alkali or
alkaline earth metals, e.g., sodium, potassium, lithium, calcium,
and magnesium. The most commonly used metals are calcium and
magnesium, which may both be present in detergents used in a
lubricant, and mixtures of calcium and/or magnesium with sodium.
Particularly convenient metal detergents are neutral and overbased
calcium sulphonates having TBN of from 20 to 450 TBN, and neutral
and overbased calcium phenates and sulphurized phenates having TBN
of from 50 to 450.
[0094] Dihydrocarbyl dithiophosphate metal salts are frequently
used as anti-wear and antioxidant agents. The metal may be an
alkali or alkaline earth metal, or aluminium, lead, tin,
molybdenum, manganese, nickel or copper. The zinc salts are most
commonly used in lubricating oil in amounts of 0.1 to 10,
preferably 0.2 to 2 wt. %, based upon the total weight of the
lubricating oil composition. They may be prepared in accordance
with known techniques by first forming a dihydrocarbyl
dithiophosphoric acid (DDPA), usually by reaction of one or more
alcohol or a phenol with P.sub.2S.sub.5 and then neutralising the
formed DDPA with a zinc compound. The zinc dihydrocarbyl
dithiophosphates can be made from mixed DDPA which in turn may be
made from mixed alcohols. Alternatively, multiple zinc
dihydrocarbyl dithiophosphates can be made and subsequently
mixed.
[0095] Thus the dithiophosphoric acid containing secondary
hydrocarbyl groups used in this invention may be made by reacting
mixtures of primary and secondary alcohols. Alternatively, multiple
dithiophosphoric acids can be prepared where the hydrocarbyl groups
on one are entirely secondary in character and the hydrocarbyl
groups on the others are entirely primary in character. To make the
zinc salt any basic or neutral zinc compound could be used but the
oxides, hydroxides and carbonates are most generally employed.
Commercial additives frequently contain an excess of zinc due to
use of an excess of the basic zinc compound in the neutralisation
reaction.
[0096] The preferred zinc dihydrocarbyl dithiophosphates useful in
the present invention are oil soluble salts of dihydrocarbyl
dithiophosphoric acids and may be represented by the following
formula:
##STR00004##
wherein R and R' may be the same or different hydrocarbyl radicals
containing from 1 to 18, preferably 2 to 12, carbon atoms and
including radicals such as alkyl, alkenyl, aryl, arylalkyl, alkaryl
and cycloaliphatic radicals. Particularly preferred as R and R'
groups are alkyl groups of 2 to 8 carbon atoms. Thus, the radicals
may, for example, be ethyl, n-propyl, i-propyl, n-butyl, i-butyl,
sec-butyl, amyl, n-hexyl, i-hexyl, n-octyl, decyl, dodecyl,
octadecyl, 2-ethylhexyl, phenyl, butylphenyl, cyclohexyl,
methylcyclopentyl, propenyl, butenyl. In order to obtain oil
solubility, the total number of carbon atoms (i.e. R and R') in the
dithiophosphoric acid will generally be about 5 or greater. The
zinc dihydrocarbyl dithiophosphate can therefore comprise zinc
dialkyl dithiophosphates. At least 50 (mole) % of the alcohols used
to introduce hydrocarbyl groups into the dithiophosphoric acids are
secondary alcohols.
[0097] Additional additives are typically incorporated into the
compositions of the present invention. Examples of such additives
are antioxidants, anti-wear agents, friction modifiers, rust
inhibitors, anti-foaming agents, demulsifiers, and pour point
depressants.
[0098] Pour point depressants, otherwise known as lube oil flow
improvers, lower the minimum temperature at which the fluid will
flow or can be poured. Such additives are well known. Typical of
those additives which improve the low temperature fluidity of the
fluid are C.sub.8 to C.sub.18 dialkyl fumarate/vinyl aceteate
copolymers and polyalkylmethacrylates.
[0099] Foam control can be provided by many compounds including
antifoamant of the polysiloxane type, for example, silicone oil or
polydimethyl siloxane.
[0100] When lubricating compositions contain one or more of the
above-mentioned additives, each additive is typically blended into
the base oil in an amount which enables the additive to provide its
desired function. Representative effective amounts of such
additives, when used in a marine diesel lubricant are as
follows:
TABLE-US-00001 Mass % a.i.* Mass % a.i.* Additive (Broad)
(Preferred) Detergent(s) 1-18 3-12 Dispersant(s) 0.5-5 1-3
Anti-wear agent(s) 0.1-1.5 0.5-1.3 Pour point depressant 0.03-0.15
0.05-0.1 Mineral or synthetic base oil Balance Balance *Mass %
active ingredient based on the final oil.
[0101] The components may be incorporated into a base oil in any
convenient way. Thus, each of the components can be added directly
to the oil by dispersing or dissolving it in the oil at the desired
level of concentration. Such blending may occur at ambient
temperature or at an elevated temperature.
[0102] Preferably all the additives except for the pour point
depressant are blended into a concentrate or additive package that
is subsequently blended into basestock to make finished lubricant.
Use of such concentrates is conventional. The concentrate will
typically be formulated to contain the additives in proper amounts
to provide the desired concentration in the final formulation when
the concentrate is combined with a predetermined amount of
basestock.
[0103] Preferably the concentrate is made in accordance with the
method described in U.S. Pat. No. 4,938,880. That patent describes
making a premix of ashless dispersant and metal detergents that is
pre-blended at a temperature of at least about 100.degree. C.
Thereafter the pre-mix is cooled to at least 85.degree. C. and the
additional components are added.
[0104] The final formulations may employ from 2 to 30 mass % and
preferably 10 to 25 mass %, typically about 15 to 23 mass % of the
concentrate or additive package with the remainder being base
oil.
[0105] The invention will now be described by way of illustration
only with reference to the following examples. In the examples,
unless otherwise noted, all treat rates of all additives are
reported as mass percent active ingredient.
Synthesis of Sulphurized Dodecylphenol
Charges:
[0106] Charge weights (g) to make approx. 1 kg of sulphurized
dodecylphenol:
TABLE-US-00002 Charge (g) Reactor Dodecylphenol 1102 Measuring
cylinder Sulphur monochloride 275 Caustic trap Sodium hydroxide 800
(50% aqueous) Water 800 Reactor addition Dec-1-ene 202
Heating Profile
Day 1:
TABLE-US-00003 [0107] Start Target Dwell Temp. Temp. Ramp Time Time
(.degree. C.) (.degree. C.) (min.) (min.) Ambient 60 10 2 60 80 120
90 80 85 30 2 85 110 30 180
Days 2 and 3:
TABLE-US-00004 [0108] Start Target Dwell Temp. Temp. Ramp Time Time
(.degree. C.) (.degree. C.) (min.) (min.) Ambient 110 40 2 110 175
50 Hold
Method
Day 1
[0109] Sulphur monochloride (SMC) is corrosive and toxic, and
therefore the following method of charging was used to minimize the
risk of exposure. A charge of SMC, close to the proposed weight,
was first poured into a 150 ml beaker and from there to a 100 ml
measuring cylinder which had been placed on a balance. The exact
weight was recorded from which the dodecylphenol (DDP) charge was
calculated. The caustic trap was set up at this stage by charging a
3 litre beaker with sodium hydroxide solution.
[0110] The DDP was then weighed into a 1 litre baffled flask. The
flask was set up for reflux and heated to 60.degree. C. under a
nitrogen blanket using the above profile. At 60.degree. C. the
sulphur monochloride addition was started via a peristaltic pump
over 4 hours using two 16 gauge flat ended stainless steel needles
joined by viton tubing. The weight loss over time was noted varying
the addition rate as necessary. During this time, while the
temperature was allowed to follow the programmed ramp given above,
the stirrer was adjusted to keep the mixture stirring briskly. The
mixture thickened during addition; stirring was started at approx.
270 rpm and had been increased to 500 rpm by the end of
addition.
[0111] At the end of addition the stainless needle and septum were
removed, a nitrogen sparge was placed in the vessel and nitrogen
bubbled through the mixture at 200 ml min.sup.-1. The temperature
was ramped to 110.degree. C. following the profile and then the
mixture was held at 110.degree. C. for 3 hours. The stirrer was
turned down to 240 rpm at 110.degree. C. because the mixture became
much thinner.
[0112] Finally the heating was stopped, the funnel to the trap
raised out of the solution, the mixture air-cooled to below
60.degree. C. (raising the sparge out of the solution at 85.degree.
C.) and the nitrogen flow stopped. It was left standing
overnight.
Day 2:
[0113] Nitrogen sparge and stirring were restarted as before. The
viscous mixture was heated gently until mechanical stirring could
be switched on. The prep was then heated to 110.degree. C. in 40
minutes. At 110.degree. C. decene was added (17% of estimated
sulphurized DDP) and the mixture was heated to 175.degree. C. in a
further 50 minutes.
[0114] The prep was held at 175.degree. C. for up to 6 hours until
the required UV ratio (see below) was reached and then the heating
was switched off but stirring and nitrogen were continued until the
prep had cooled below 60.degree. C. The prep was then switched
off.
[0115] UV ratio: The UV ratio of absorbances at 291:325 nm was
measured on sulphurized DDP samples to determine the extent of
polysulphide breakdown from the initial reaction. The peak at 325
nm was expected to diminish during a successful desulphurization to
produce a final ratio exceeding 3.0.
Day 3:
[0116] The caustic trap was removed and the flask set up for
distillation. Nitrogen blanket and stirring were started and the
prep heated to 175.degree. C. using the same profile as in Day 2.
The mixture was much thinner that on day 2 due to the decene
addition and stirring could be started immediately. At 175.degree.
C. high vacuum was applied and held for 2 hours. At the end of 2
hours the heating was switched off and the prep cooled to below
60.degree. C. under vacuum with stirring and nitrogen still on.
Once below 60.degree. C. the prep was switched off. In the case of
A (see Table below) the sulphurized DDP was then used as such. In
the case of B (see Table below) the product obtained was blended
with SN 150 oil (14%) at 60.degree. C. for 1 hr.
Synthesis of Overbased Phenates
EXAMPLES A (PHENATE/STEARATE) AND B
(PHENATE/SULPHONATE/STEARATE)
Charges:
TABLE-US-00005 [0117] Mass (g) Example A Example B Reactor Toluene
695 632 Methanol 397 361 Water 26 24 Oil, SN 150 30 30 Sulphurized
dodecylphenol 622 Sulphurized dodecylphenol 457 Alkylbenzene
sulphonic acid 0 39 (Mol. Wt. approx. 660, active matter 83%)
Reactor Additions Calcium hydroxide 212 195 Carbon dioxide 65 66
Oil, SN 150 (second oil charge) 144 178 Stearic Acid 93 84
Centrifuge addition Toluene (further toluene charge) 1072 431
Heating Profile:
TABLE-US-00006 [0118] Start Temp Final Temp Ramp Time Dwell Time
(.degree. C.) (.degree. C.) (min.) (min.) Ambient 40 10 2 40 28 10
2 28 60 60 2 60 65 15 -- 65 70 90 -- 70 75 15 -- 75 110 50 -- 110
120 15 Hold
Method:
[0119] The toluene, methanol, water and initial oil were weighed
into a 2 litre reaction vessel. The vessel was set up for reflux
and heated to 40.degree. C. using the above heating profile. The
mixture was stirred at 200 rpm. Calcium hydroxide was added at
33.degree. C. At 40.degree. C. stirring was increased to 400 rpm
and the sulphurized dodecylphenol (and alkylbenzene sulphonic acid,
if required) were run in over a period of approx. 25 minutes. The
prep was then cooled back to 28.degree. C.
[0120] At 28.degree. C. carbonation was started at a rate of
approx. 150 ml min-1. Carbonation time was 180 minutes.
[0121] Heat soak: after carbonation the mixture was ramped from
28.degree. C. to 60.degree. C. using the above profile. The stearic
acid was added at 60.degree. C. at the end of the heat soak. After
adding the stearic acid the reaction vessel was rearranged for
distillation and a blanket of nitrogen was applied. The mixture was
stripped according to the above profile. The second oil charge was
added at 120.degree. C.
[0122] Centrifugation: The product was decanted into a 3 litre
beaker and weighed. A further toluene charge was added to the
beaker and stirred. The mixture was transferred into centrifuge
cans and spun in a centrifuge at 2500 rpm for 30 min. After
spinning the mixtures were decanted to be stripped on a rotary
evaporator.
[0123] Rotary Evaporator Strip: The oil bath was pre-heated to
160.degree. C. and was maintained at this temperature
.+-.10.degree. C. An empty 2 litre pear shaped flask was placed on
the rotovap, spun briskly and a vacuum of approx. 400 mbar was
applied. The supernatant liquid was then bled in slowly over
approx. 40 min. and the solvent allowed to flash off. After all the
mixture had been added the vacuum was increased to full vacuum and
maintained for 1 hour. After 1 hour the vacuum was released and the
product was cooled.
[0124] The overbased detergent produced had the following
characteristics:
TABLE-US-00007 Comparative Example- Example A Example B OLOA 219*
TBN 258 258 250 Unsulphurized 5.58 3.84 6.15 alkyl phenol and its
unsulphurized calcium salt, mass % *OLOA 219 is a commercially
available 250 BN calcium phenate.
[0125] The detergents in the table above were tested for their
rates of neutralization using the following test method:
Acid Neutralisation Rig Method
[0126] A 100 ml two neck round bottom flask was fitted with a
digital manometer (Digitron model 2083) and an injection port
consisting of a glass tap and quick fit adapter. The flask was
charged with 30 g of sample (to 0.1 mg) and a magnetic stirrer
added. The flask was placed in an oil bath at 40.degree.
C..+-.1.degree. C. and the sample was allowed to reach equilibrium.
0.182 g of 18M sulphuric acid was charged to a syringe and injected
into the flask via the injection port and the pressure of the
CO.sub.2 gas evolved was recorded as a function of time. The
results are shown in the table below and also in the attached
graph.
[0127] The amount of dodecyl phenol (DDP) and its calcium salt was
measured as follows:
Method for Analysis of (Ca) DDP Content
[0128] The determination of dodecyl phenol (DDP) and its calcium
salt content was done by reverse phase HPLC using a u.v. detector.
Alkylphenol species were differently eluted within ten minutes. The
remaining sample impurities were washed out from the column with
pure methanol A series of four calibration standards were prepared
by dissolving known amounts of reference DDP in the mobile phase
(84% methanol-16% water), concentrations were selected according to
the most appropriate range of detector response factor and
linearity. Analyses of test specimens were carried out within the
calibration range of response. About 0.3 g of sample solution was
dissolved in about 3 g of dichloromethane (AR grade). The solution
was gently agitated. A 20 ml volumetric flask was half filled with
the mobile phase and into this, about 2.6 g of the dichloromethane
solution was directly weighed (to nearest 0.1 mg). The sample was
homogenised by agitation or by sonication in a water bath for 2
minutes. The flask was diluted to volume with mobile phase and
then, by means of a 5 mL plastic syringe and a 0.45 .mu.m
disposable cellulose acetate filter, the sample was filtered
directly into the HPLC vial. The sample and calibration solutions
were chromotographed using the HPLC conditions below. Integration
of the peaks was carried out between 4 and 9 minutes, the baseline
being flat (the slope being less than 5%) with no drift of the u.v.
detector. The reference point for the baseline was taken at 9
minutes. A linear calibration curve was generated by plotting the
integrated areas of the standards against the amount of DDP used to
prepare the standards. This calibration curve was used to determine
the content of DDP and its calcium salt by combined mass % in the
sample.
[0129] The HPLC was run with the following conditions:
Column: C8(2) 150 mm.times.4.6 mm, 5 .mu.m particles size (Luna
100A Phenomex column or equivalent);
[0130] Flow rate: 1.2 mL/min; Mobile phase: methanol 84% and water
16%; Typical injection volume: 5 .mu.l; Total run time: 38 min;
0-10 min 84% methanol-16% water; 10.10-20.00 min 100% methanol
(column wash); 20.10-38.00 min 84% methanol-16% water; Temperature
of the column compartment: 40.degree. C.; UV detector settings:
Wavelength: 230 nm (reference at 360 nm for DAD systems).
TABLE-US-00008 Comparative Example 1 Example 2 Example 3 Example 4
Example A 8.00 16.00 Example B 16.00 OLOA 219 16.00 425 BN 7.10
7.10 7.10 7.10 Calcium Sulphonate, Infineum M7117 ExxonMobil 64.90
56.90 56.90 56.90 SN600 ExxonMobil 20.00 20.00 20.00 20.00 BS 2500
TBN 50 70 70 70 VK @ 40.degree. C. 180.2 196.6 211.8 209.7
TABLE-US-00009 Acid Neutralization Testing, CO.sub.2 pressure
changes Comparative Time, minutes Example 1 Example 2 Example 3
Example 4 0 0 0 0 0 1 28.0 26.5 27.0 10.8 2 35.0 29.8 27.8 12.5 3
38.7 32.0 29.2 13.3 4 41.7 34.3 31.0 13.5 5 45.0 36.0 32.0 13.5 6
47.0 37.0 33.0 13.8 7 49.0 38.3 33.8 13.8 8 50.3 39.8 35.0 14.0 9
51.7 41.0 35.4 14.3 10 53.2 41.8 35.6 14.3 11 53.7 42.3 35.8 14.5
12 54.3 42.5 36.2 14.0 13 55.7 42.8 36.4 14.5 14 56.7 42.5 36.0
14.3 15 57.0 43.5 36.0 14.5 16 56.7 43.8 36.0 14.0 17 57.3 44.5
36.0 14.0 18 57.7 44.0 35.8 13.8 19 57.7 43.8 35.8 14.0 20 57.7
43.8 35.8 14.3
[0131] The results above show that the use of an overbased
sulphurized metal phenate including less than 6.0% by mass of
unsulphurized C.sub.9-C.sub.15 alkyl phenol and its unsulphurized
metal salt unexpectedly produces a higher rate of acid
neutralization than the use of an overbased sulphurized metal
phenate including more than 6.0% by mass of unsulphurized
C.sub.9-C.sub.15 alkyl phenol and its unsulphurized metal salt.
* * * * *