Note: Descriptions are shown in the official language in which they were submitted.
lZO~:~41
Title: "Nitrogen-Containing Esters and Lubricants Containing Them"
TECHNICAL FIELD
This invention relates to nitrogen-containing esters of carboxy-
containing interpolymers and to lubricating compositions and additive con-
centrates containing such esters. More particularly, this invention relates
to interpolymers derived from low molecular weight olefin or styrene and
alpha, beta-unsaturated aliphatic acid, anhydride or ester thereof, such
interpolymers being esterified with long chain aliphatic alcohols and
neutralized with polyamino compounds having one primary or secondary
amino group and at least one mono-functional amino group, the resulting
nitrogen-containing esters being particularly useful as pour point depress-
ants.
BACKGROUND OF THE INVENTION
Ever since lubricating oils were prepared from crude oils,
refiners have experienced difficulty with congealation of these products at
low temperatures. Part of the difficulty arises from a natural stiffening at
low temperatures of the hydrocarbons comprising the bulk of the oil. This
type of congealation can be corrected quite easily by the use of a solvent
such as kerosene to reduce the viscosity of the oil. The remainder of the
difficulty arises from the crystallization at low temperatures of the paraffin
wax present in almost all heavy mineral oil fractions. Upon crystallization,
the paraffin wax tends to form interlocking networks which adsorb oil and
form a voluminous gel-like structure which restricts the flow or "pour" of
the oil. Even though refining processes known as dewaxing have been
developed to remove most of the paraffin from lubricating oil fractions, the
small amount of wax remaining after dewaxing can cause serious problems.
Even such small amounts of wax can raise by tens of degrees Fahrenheit the
temperature at which an oil will flow freely as measured by a suitable "pour
point" test. Since removal of the last traces of wax from oils is a difficult
and costly matter, other answers have been sought by refiners.
Various pour point depressants have been developed and those to
reach the commercial market have primarily been organic polymers, al-
though some monomeric substances such as tetra (long chain alkyl) silicates,
$~.
lZ~9~4~
phenyl tristearyloxysilane, and pentaerythritol tetrastearate have been
shown to be effective. Presently available commercial pour point depress-
ants are believed to be represented by the following types of polymeric
materials: polymethacrylates, for example, copolymers of various chain
length alkyl methacrylates (see, for example, U.S. patent 2,655,479); poly-
acrylamides (see, for example, U.S. patent 2,387,501); Friedel-Crafts con-
densation products of chlorinated paraffin wax with naphthalene (see, for
example, U.S. patents 1,815,022 and 2,015,748); Friedel-Crafts condensation
products of chlorinated paraffin wax with phenol (see, for example, U.S.
patent 2,191,498); and vinyl carboxylate, such as dialkyl fumarate copolymers
(see, for example, U.S. patents 2,666,746; 2,721,877 and 2,721,878).
Esters of maleic anhydride/alpha-olefin copolymers have been
suggested as pour point depressants. or example, U.S. Patent 2,977,334
describes the use of copolymers of maleic anhydride and ethylene which are
esterified with low or high molecular weight alcohols and/or amidized with
an amine. These resins are described as being useful as pour point
modifiers, gelling agents, thickeners, viscosity improvers, etc., for mineral
and synthetic oils including functional fluids and lubricating oils. U.S.
Patent 2,992,987 describes a class of lubricant additives useful as pour point
depressants which are ethylene-maleic anhydride copolymers esterified to
80% or more, preferably 90-100%, with a mixture of straight-chain saturated
hydrocarbon alcohols having from 8 to 24 carbon atoms. The unesterified
carboxylic groups can be left unreacted or can be reacted with such
materials as ethylene or propylene oxide alcohol esters, or lower-dialkyl-
amino-lower-alkyleneamines. U.S. Patents 3,329,658 and 3,449,250 de-
scribes copolymers of maleic anhydride and alpha-olefins such as ethylene,
propylene, isobutylene or styrene as being useful dispersancy and detergency
additives for oils, as well as pour point depressants and viscosity index
improvers. The copolymer is esterified to about 30 to about 95% with
aliphatic alcohols or mixtures of alcohols having from 10 to 20 carbon atoms,
and the remaining carboxyl groups are reacted with an amine of the
following formula
Rl R4
N--R3--N
R2 H
~2~9~41
where Rl and R2 are selected from the group consisting of aliphatic
hydrocarbon radicals having from 1 to 4 carbon atoms and the cyclohexyl
radical, R3 is an aliphatic hydrocarbon radical having from 2 to 4 carbon
atoms, and R4 is selected from the class consisting of hydrocarbon atom and
aliphatic hydrocarbon radicals having from 1 to 4 carbon atoms.
U.S. Patents 3,702,300 and 3,933,761 describe carboxy-containing
interpolymers in which some of the carboxy radicals are esterified and the
remaining carboxy radicals are neutralized by reaction with a polyamino
compound having one primary or secondary amino group and at least one
mono-function,ql amino group, and indicate that such interpolymers are
useful as viscosity index improving and anti-sludge agents in lubricating
compositions and fuels. The patentee indicates that it is critical that the
mixed esters described in these patents include both relatively high mole-
cular weight carboxylic ester groups having at least eight aliphatic carbon
atoms in the ester radical and relatively low molecular weight carboxylic
ester groups having no more than seven aliphatic carbon atoms in the ester
radical.
Although many pour point depressants have been suggested and
many are available in the market, concerted efforts are constantly being
made to find new pour point depressants which are more economical and
more effective than the depressants heretofore known in the art. In
particular, a great deal of interest exists in pour point depressants which are
capable of imparting other desirable properties to the lubricating composi-
tions to which they are added in addition to pour point depressant proper-
ties.
SUMMARY OF THE INVENTION
Nitrogen-containing esters of carboxy-containing interpolymers
are provided in accordance with the present invention which when added to
lubricant compositions provide such lubricant compositions with superior
pour point depressant properties as well as other desirable properties
including viscosity index improvement. These esters also enhance the
dispersion of other additives as well as contaminants (e.g., dirt, water,
metallic particles, etc.) in the lubricating compositions to which they are
~9141
added. These esters also enhance the flow characteristics of additive
concentrates to which they are added.
Broadly stated, the present invention contemplates the provision
of a nitrogen-containing ester of a carboxy-containing interpolymer, said
interpolymer having a reduced specific viscosity of from about 0.05 to about
1 and being derived from at least two monomers, one of said monomers being
a low molecular weight aliphatic olefin or styrene and the other of said
monomers being an alpha, beta-unsaturated aliphatic acid, anhydride or
ester thereof, said nitrogen-containing ester being substantially free of
titratable acidity and being characterized by the presence within its
polymeric structure of at least one of each of the following groups which
are derived from the carboxy groups of said interpolymer:
(A) a carboxylic ester group, said carboxylic ester group having
at least eight aliphatic carbon atoms in the ester radical,
and
(B) a carbonyl-polyamino group derived from a polyamino
compound having one primary or secondary amino group
and at least one mono-functional amino group,
wherein the molar ratio of carboxy groups of said interpolymer esterified to
provide (A) to carboxy groups of said interpolymer neutralized to provide (B)
is in the range of about 85:15 to about 99:1.
Lubricant compositions and additive concentrates comprising the
foregoing nitrogen-containing ester are also provided in accordance with the
present invention. Further, the present invention contemplates the pro-
vision of a process for making a nitrogen-containing ester of a carboxy-
containing interpolymer comprising the steps of: providing an interpolymer
derived from at least two monomers, one of said monomers being a low
molecular weight aliphatic olefin or styrene and the other of said monomers
being an alpha, beta-unsaturated aliphatic acid, anhydride or ester thereof,
said interpolymer having a reduced specific viscosity of about 0.05 to about
l; partially esterifying said interpolymer with an alcohol having at least
eight aliphatic carbon atoms to convert from about 85% to about 99% of the
carboxy radicals of the interpolymer to ester radicals; and substantially
neutralizing the remaining carboxy radicals of said interpolymer with a
~Z~914~
polyamino compound having one primary or secondary amino group and at
least one mono-functional amino group.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
An essential element of the present invention is that each of the
carboxylic ester groups of the nitrogen-containing esters of the present
invention have at least eight aliphatic carbon atoms in the ester radical.
The presence of carboxylic ester groups of such size is critical to the stable
pour point properties imparted to the lubricating compositions in which the
nitrogen-containing esters of the present invention are used.
In reference to the size of the ester groups, it is pointed out that
an ester radical is represented by the formula
--C(O)(OR)
and that the number of carbon atoms in an ester radical is thus the
combined total of the carbon atom of the carbonyl group and the carbon
atoms of the ester group, i.e., the (OR) group.
Another essential element of the present invention is the pre-
sence of a polyamino group derived from a particular polyamino compound,
i.e., one in which there is one primary or secondary amino group and at least
one mono-functional amino group. Such polyamino group, when present in
the nitrogen-containing esters of the present invention in the proportion
stated above enhances the dispersability of such esters in lubricant composi-
tions and additive concentrates for lubricant compositions.
Still another essential element of the present invention is the
extent of esterification in relation to the extent of neutralization of the
unesterified carboxy groups of the carboxy-containing interpolymer through
the conversion thereof to polyamino-containing groups. The molar ratio of
the carboxy groups of said interpolymer that are esterified to the carboxy
groups neutralized through the conversion thereof to polyamino-containing
groups is generally in the range of about 85:15 to about 99:1. A preferred
ratio is 95:5. It should be noted that the linkage described as the carbonyl-
polyamino group may be imide, amide, or amidine and inasmuch as any such
linkage is contemplated within the present invention, the term "carbonyl
polyamino" is thought to be a convenient, generic expression useful for the
12~914~
purpose of defining the inventive concept. In a particularly advantageous
embodiment of the invention such linkage is imide or predominantly imide.
Still another important element of the present invention is the
molecular weight of the carboxy-containing interpolymer. For convenience,
the molecular weight is expressed in terms of the 'treduced specific
viscosity" of the interpolymer which is a widely recognized means of
expressing the molecular size of a polymeric substance. As used herein, the
reduced specific viscosity (abbreviated as RSV) is the value obtained in
accordance with the formula
RSV = Relative ~iscosity--1
Concentration
wherein the relative viscosity is determined by measuring, by means of a
dilution viscometer, the viscosity of a solution of one gram of the
interpolymer in 100 ml. of acetone and the viscosity of acetone at 30~
0.02C. Fdr purpose of computation by the above formula, the concentra-
tion is adjusted to 0.4 gram of the interpolymer per 100 ml. of acetone. A
more detailed discussion of the reduced specific viscosity, also known as the
specific viscosity, as well as its relationship to the average molecular
weight of an interpolymer, appears in Paul J. Flory, Principles of Polymer
Chemistry, (1953 Edition) pages 308 et seq.
While interpolymers having a reduced specific viscosity of from
about 0.05 to about 1 are contemplated in the present invention, the
preferred interpolymers are those having a reduced specific viscosity of
from about 0.2 or 0.35 to about 0.8 or 1. Interpolymers having a reduced
specific viscosity of from about 0.35 to about 0.5 or from about 0.65 to
about 0.75 are particularly useful.
From the standpoint of utility, as well as for commercial and
economical reasons, nitrogen-containing esters in which the ester group has
from 8 to 24 aliphatic carbon atoms, preferably about 12 to about 18 carbon
atoms, and most preferably about 14 or 15 carbon atoms, and the carbonyl
polyamino group is derived from a primary-aminoalkyl-substituted tertiary
amine, particularly heterocyclic amine, are preferred. specific examples of
the carboxylic ester group, i.e., the (OR) group of the ester radical (i.e.,--
(O)(OR)) include isooctyloxy, decyloxy, dodecyloxy, tridecyloxy, tetradecyl-
oxy, pentadecyloxy, octadecyloxy, eicosyloxy, tricosyloxy, tetracosyloxy,
~209141
etc. In most instances, alkoxy groups comprise the preferred ester groups.
Polar substituents may be present in such ester groups. Examples of polar
substituents are chloro, bromo, ether, nitro, etc. Mixtures of the foregoing
carboxylic ester groups can also be provided. For example, mixtures of
ester groups having from 12 to 18 carbon atoms have been found to be useful.
Mixtures of ester groups having 14 and 15 carbon atoms have been found to
be particularly advantageous.
Examples of the carbonyl polyamino group include those derived
from polyamino compounds having one primary or secondary amino group
and at least one mono-functional amino group such as tertiary-amino or
heterocyclic amino group. Such compounds may thus be tertiary-amino
substituted primary or secondary amines or other substituted primary or
secondary amines in which the substituent is derived from pyrroles, pyrroli-
dones, caprolactams, oxazolidones, oxazoles, thiazoles, pyrazoles, pyrazol-
ines, imidazoles, imidazolines, thiazines, oxazines, diazines, oxycarbamyl,
thiocarbamyl, uracils, hydantoins, thiohydantoins, guanidines, ureas, sulfona-
mides, phosphoramides, phenolthiazines, amidines, etc. Examples of such
polyamino compounds include dimethylamino-ethylamine, dibutylamino-
ethylamine, 3-dimethylamino-1-propylamine, 4-methylethylamino-1-butyl-
amine, pyridyl-ethylamine, N-morpholino-ethylamine, tetrahydropyridyl-
ethylamine, bis-(dimethylamino~propylamine, bis-(diethylamino)ethylamine,
N,N-dimethy~p-phenylene diamine, piperidyl-ethylamine, l-aminoethyl
pyrazole, l-(methylamino)pyrazoline, l-methyl-4-aminooctyl pyrazole, 1-
aminobutyl imidazole, 4-aminoethyl thiazole, 2-aminoethyl triazine, di-
methylcarbamyl propylamine, N-methyl-N-aminopropyl acetamide, N-
aminoethyl succinimide, N-methylamino maleimide, N-aminobutyl-alpha-
chlorosuccinimide, 3-aminoethyl uracil, 2-aminoethyl pyridine, ortho-amino-
ethyl-N,N-dimethylbenzenesulfamide, N-aminoethyl phenothiazine, N-
aminoethylacetamidine, l-aminophenyl-2-methyl-imidazoline, N-methyl-N-
aminoethyl-S-ethyl-dithiocarbamate, etc. Preferred polyamino compounds
include the N-aminoalkyl-substituted morpholines such as aminopropyl mor-
pholine. For the most part, the polyamino compounds are those which
contain only one primary-amino or secondary-amino group and, preferably at
least one tertiary-amino group. The tertiary amino group is preferably a
12~9~41
--8--
heterocyclic amino group. In some instances polyamino compounds may
contain up to about 6 amino groups although, m most instances, they contain
one primary amino group and either one or two tertiary amino groups. The
polyamino compounds may be aromatic or aliphatic amines end are prefer-
ably heterocyclic amines such as amino-alkyl-substituted morpholines,
piperazines, pyridines, benzopyrroles, quinolines, pyrroles, etc. They are
usually amines having from 4 to about 30 carbon atoms, preferably from 4 to
about 12 carbon atoms. Polar substituents may likewise be present in the
polyamines.
The carboxy-containing interpolyrrlers include principally inter-
polymers of alpha, beta-unsaturated acids or anhydrides such as maleic
anhydride or itaconic anhydride with olefins (aromatic or aliphatic) such as
ethylene, propylene, styrene, or isobutene. The styrene-maleic anhydride
interpolymers are especially useful. They are obtained by polymerizing
equal molar amounts of styrene and maleic anhydride, with or without one
or more additional interpolymerizable comonomers. In lieu of styrene, an
aliphatic olefin may be used, such as ethylene, propylene or isobutene. In
lieu of maleic anhydride, acrylic acid or methacrylic acid or ester thereof
may be used. Such interpolymers are known in the art and need not be
described in detail here. Where an interpolymerizaWe comonomer is
contemplated, it should be present in a relati-;ely minor proportion, i.e., lessthan about 0.3 mole, usually less than about 0.15 mole, per mole of either
the olefin (e.g. styrene) or the alpha, beta-unsaturated acid or anhydride
(e.g. maleic anhydride). Various methods of interpolymerizing styrene and
maleic anhydride are known in the art and need not be discussed in detail
here. For purpose of illustration, the interpolymerizable comonomers
include the vinyl monomers such as vinyl acetate, acrylonitrile, methyl-
acrylate, methylmethacrylate, acrylic acid, vinyl methyl ether, vinyl ethyl
ether, vinyl chloride, isobutene or the like.
The nitrogen-containing esters of the invention are most con-
veniently prepared by first esterifying the carboxy-containing interpolymer
with an alcohol to convert at least about 85% and no more than about 99~6
of the carboxy radicals of the interpolymer to ester radicals and then
1209~41
neutralizing the remaining carboxy radicals with a polyamino compound such
as described above. More than one alcohol may be used in the process; so
also may be used commercial alcohol mixtures such as the so-called Oxo-
alcohols which comprise, for example, mixtures of alcohols having from 8 to
about 24 carbon atoms. A particularly useful class of alcohols are the
commercial alcohol mixtures or mixtures of commercial alcohol mixtures
comprising dodecyl alcohol, tridecyl alcohol, tetradecyl alcohol, pentadecyl
alcohol, hexadecyl alcohol, heptadecyl alcohol and octadecyl alcohol. Com-
mercial alcohol mixtures of tetradecyl and pentadecyl alcohols are particu-
larly useful. Several suitable sources of these Plcohol mixtures are the
technical grade alcohols sold under the tradename ~Neodols~ by Shell
Chemical Corporation and under the tradename "Alfols'~by Continental Oil
Company. Other alcohols useful in the process are illustrated by those
which, upon esterification, yield the ester groups exemplified above.
The extent of esterification, as indicated previously, may range
from about 85% to about 99%, preferably about 92% to about 97%,
conversion of the carboxy radicals of the interpolymer to ester radicals. In
a preferred embodiment, the degree of esterification is about 95%.
The esterification can be accomplished simply by heating the
carboxy-containing interpolymer and the alcohol or alcohol mixtures under
conditions typical for effecting esterification. Such conditions usually
include, for example, a temperature of at least about 80C, preferably from
about 150C to about 350C, provided that the temperature be below the
decomposition point of the reaction mixture, and the removal of water of
esterification as the reaction proceeds. Such conditions may optionally
include the use of an excess of the alcohol reactant so as to facilitate
esterification, the use of a solvent or diluent such as mineral oil, toluene,
benzene, xylene or the like and an esterification cstalyst such as toluene
sulfonic acid, sulfuric acid, aluminum chloride, boron trifluoride-triethyl-
amine, hydrochloric acid, ammonium sulfate, phosphoric acid, sodium meth-
oxide or the like. These conditions and variations thereof are well known in
the art.
The esterified interpolymer is then treated with a polyamino
raze rn~ks
1209141
--10-
compound in an amount so as to neutralize substantially all of the un-
esterified carboxy radicals of the interpolymer. The neutrPlization is
preferably carried out at a temperature of at least about 80C, often from
about 120C to about 300C, provided that the temperature does not exceed
the decomposition point of the reaction mass. In most instances the
neutralization temperature is between about 150C and 250C. A slight
excess of the stoichiometric amount of the polyamino compound is often
desirable, so as to insure substantial completion of neutralization, i.e., no
more than about 2% of the carboxy radicals initially present in the
interpolymer remained unneutralized.
The following examples are illustrative of the preparation of the
nitrogen-containing esters of the present invention. Unless otherwise
indicated all parts and percentages are by weight.
Example 1
A styren~maleic interpolymer is obtained by preparing a solu-
tion of styrene (536 parts) and maleic anhydride (505 parts) in toluene (7585
parts) and contacting the solution at a temperature of 99-101C and an
absolute pressure of 480-535 mm. Hg. with a catalyst solution prepared by
dissolving benzoyl peroxide (2.13 parts) in toluene (51.6 parts). The catalyst
solution is added over a peiod of 1.5 hours with the temperature maintained
at 99-101C. Mineral oil (2496 parts) is added to the mixture. The mixture is
maintained at 99-101C and 480-535 mm. Hg. for 4 hours. The resulting
product is a slurry of the interpolymer in the solvent mixture. The resulting
interpolymer has a reduced specific viscosity of 0.42.
Example 2
A toluene slurry (2507 parts), having 11.06% solids and 88.94%
volatiles, of the maleic anhydride/styrene interpolymer of Example 1,
Neodol 45 (631 parts), a product of Shell Chemical Company identified as a
mixture of C14 and Cls linear primary alcohols, mineral oil (750 parts), and
Ethyl Antioxidant 733 (4.2 parts), a product of Ethyl identified as an
isomeric mixture of butyl phenols, are charged to a vessel. The mixture is
heated with medium agitation under nitrogen purge at 0.5 standard cubic
feet per hour until the temperature reaches 115C. 70% methane sulfonic
~2Q9141
acid catalyst in water (10.53 parts) is added dropwise over a period of 20
minutes. Nitrogen purge is increased to 1.0 standard cubic feet per hour and
temperature is raised by removal of toluene-water distillate. The mixture is
maintained at a temperature of 150C for five hours under a nitrogen purge
of 0.1-0.2 standard cubic feet per hour. Additional methane sulfonic acid
solution (15.80 parts) is added to the mixture over period of 15 minutes. The
mixture is maintained at 150C for 3.5 hours. The degree of esterification is
95.08%. Amino propylmorpholine (35.2 parts) is added to the mixture
dropwise over a period of 20 minutes. The mixture is maintained at 150C
for an additional 30 minutes then cooled with stirring. The mixture is
stripped from 50C to 141C at a pressure of 102 mm. Hg. then permitted to
cool. At a temperature of 100C, mineral oil (617 parts) is added. Cooling is
continued to 60C. At 60C, diatomaceous earth (36 parts) is added and the
mixture is heated to 100C. The mixture is maintained at 100-105C for one
hour with stirring and then filtered to yield the desired product.
Example 3
The procedure of Example 2 is repeated with the exception that
both Neodol 45 (315.4 parts) and Alfol 1218 (312.5 parts), a product of
Continental Oil Company identified as a mixture of synthetic primary
straight chain alcohols having 12 to 18 carbon atoms, are initially charged,
rather than the 631 parts of Neodol 45 which were included in the initial
charge in Example 2.
Example 4
A toluene slurry (1125 parts), having 13.46% solids and 86.54%
volatiles, of the maleic anhydride/styrene interpolymer of Example 1,
mineral oil (350 parts) and Neodol 45 (344 parts) are charged to a vessel.
The mixture is heated with medium agitation under nitrogen sweep of 0.5
standard cubic feet per hour until the temperature reaches 110C. Para-
toluene sulfonic acid (8.55 parts) in water (9 parts) is added dropwise over a
period of 24 minutes. The temperature of the mixture is increased to 152C
by removing toluene-water distillate. The temperature is maintained at 152-
156C under nitrogen sweep of 0.5 standard cubic feet per hour until the net
~2~9141
-12--
acid number indicates that esterification is at least 95% complete. Amino-
propylmorpholine (15.65 parts) is added dropwise over a period of 10 minutes.
The temperature of the mixture is maintained at 155C for 1 hour and then
cooled under a nitrogen sweep. Ethyl Antioxidant 733 (1.48 parts) is added
to the mixture. The mixture is stripped at 143C and 99 mm. Hg. pressure.
The mixture is cooled under nitrogen sweep. Mineral oil is added to provide
a total of 63% dilution. Ethyl Antioxidant 733 (1.79 parts) is added and the
mixture is stirred for 30 minutes. The mixture is heated to 60C while
stirring with a nitrogen sweep of 0.5 standard cubic feet per hour.
Diatomaceous earth (18 parts) is added to the mixture. The mixture is
heated to 90C. The temperature of the mixture is maintained at 90-100C
for 1 hour and then filtered through a pad of diatomaceous earth (18 parts) in
a heated funnel to yield the desired product.
Example 5
The procedure of Example 4 is repeated with the exception that
both Neodol 45 (172 parts) and Alfol 1218 (169 parts) are provided in the
initial charge, rather than the 344 parts of Neodol 45 provided in Example 4.
Example 6
The product of Example 1 (101 parts), Neodol 91 (56 parts), a
product of Shell Chemical Company identified as a mixture of Cg, Clo, and
A a alcohols, TA-1618~92 parts), a product of Procter & Gamble identified as
a mixture of C16 and C1g alcohols, Neodol 25 (62 parts), a pPoduct of Shell
Chemical Company identified as a mixture of C12, C13, C14, and Cls
alcohols, and toluene (437 parts) are charged to a vessel. The vessel is
stirred and the contents are heated. Methane sulfonic acid (5 parts) is added
to the mixture. The mixture is heated under reflux conditions for 30 hours.
Aminopropyl morpholine (12.91 parts) is added to the mixture. The mixture
is heated under reflux conditions for an additional 4 hours. Diatomaceous
earth (30 parts) and a neutral paraffinic oil (302 parts) are added to the
mixture which is then stripped. The residue is filtered to yield 497.4 parts
of an orange-brown viscous liquid.
Example 7
The product of Example 1 (202 parts), Neodd 91(112 parts), TA
~r~de ~)1Qrk
14~
1618 (184 parts), Neodol 25 (124 parts) and toluene (875 parts) are charged to
a vessel. The mixture is heated and stirred. Methane sulfonic acid (10 parts)
is added to the mixture which is then heated under reflux conditions for 31
hours. Aminopropyl morpholine (27.91 parts) is added to the mixture which
is then heated under reflux conditions for an additional 5 hours. Diatoma-
ceous earth (60 parts) is added to the mixture which is then stripped, 600
parts of polymer remaining in the vessel. A neutral paraffinic oil (600 parts)
is added to the mixture which is then homogenized. The mixture is filtered
through a heated funnel to yield 1063 parts of a clear orange-brown viscous
liquid.
Example 8
The product of Example 1 (101 parts), Alfol 810 (50 parts), a
product of Continental Oil Company identified as a mixture of Cg and Clo
alcohols, TA-1618 (92 parts), Neodol 25 (62 parts) and toluene (437 parts) are
charged to a vessel. The mixture is heated and stirred. Methane sulfonic
acid (S parts) is added to the mixture which is heated under reflux conditions
for 30 hours. Aminopropyl morpholine (15.6 parts is added to the mixture
which is then heated under reflux conditions for an additional 5 hours. The
mixture is stripped to yield 304 parts of a yellow-orange viscous liquid.
Diatomaceous earth (30 parts) and a neutral paraffinic oil (304 parts) are
added to the mixture which is then homogenized. The mixture is filtered
through a heated funnel to yield 511 parts of a clear amber viscous liquid.
Example 9
A toluene slurry (799 parts) of a maleic anhydride/styrene
interpolymer (17.82% polymer) is charged to a vessel. The reduced specific
viscosity of the interpolymer is 0.69. The vessel is purged with nitrogen
while stirring the contents for lS minutes. Alfol 1218 (153 parts), Neodol 45
(156 parts) and 93% sulfuric acid (5 parts) are added to the mixture. Toluene
(125 parts is then added to the mixture. The mixture is heated at 150-156C
for 18 hours. Aminopropyl morpholine (1.3 parts) is added to the mixture
which is then heated for an additional 1 hour at 150C. The mixture is cooled
to 80C. Ethyl Antioxidant 733 (1.84 parts) is added to the mixture. The
mixture is stripped at 143C and 100 mm. Hg. Mineral oil (302 parts) and
~Z1~9141
-14-
Ethyl Antioxidant 733 (218 parts) are added and the mixture is stirred. The
temperature of the mixture is maintained at 90C and is blown with
nitrogen. Diatomaceous earth (44 parts) is added to the mixture which is
stirred for 1 hour at 90-95C. The mixture is filtered through diatomaceous
earth to yield 1312 parts of a dark brown clear viscous liquid.
Example 10
A toluene slurry (973 parts) of a mPleic anhydride/styrene
interpolymer (17.28% solids) is charged to a vessel. The reduced specific
viscosity of the interpolymer is 0.69. The slurry is stirred and blown with
nitrogen at 0.75-1.0 standard cubic feet per hour for 20 minutes. Neodol 45
(368 parts) and 80% sulfuric acid (6.84 parts) are added to the mixture. The
mixture is heated at 150-156C for 23 hours. Additional 80% sulfuric acid (1
part) and toluene (50 parts) are added after approximately the first 9 hours
of heating. Additional 80% sulfuric acid (2.84 parts) is added after about
the first 13 hours of heating. Additional Neodol 45 (18.4 parts) and 80%
sulfuric acid (2 parts) are added after about the first 16 hours of heating.
Aminopropyl morpholine (2.33 parts) is added to the mixture which is heated
at 153-154C for an additional 1 hour and 20 minutes. Ethyl Antioxidant 733
(2.06 parts) is added to the mixture. The mixture is stripped at 142C and
100 mm. Hg. Mineral oil (481 parts) is added to the mixture. Ethyl
Antioxidant 733 (2.5 parts) is added to the mixture while the mixture is
stirred. Diatomaceous earth (25 parts) is added to the mixture. The
temperature of the mixture is maintained at 70C for 45 minutes and then
heated to 110C. Diatomaceous earth (25 parts) is added to the mixture. The
mixture is filtered through diatomaceous earth to yield the desired product.
Example 11
A toluene and mineral oil slurry (699 parts) containing 17.28%
solids of a maleic anhydride/styrene interpolymer (reduced specific viscosity
of 0.69), Neodol 45 (139 parts), Alfol 1218 (138 parts), Ethyl Antioxidant 733
(2.9 parts) and toluene (50 parts) are charged to a vessel. The mixture is
heated under a nitrogen purge at 0.5 standard cubic feet per hour. 70%
methane sulfonic acid (3.9 parts) is added dropwise over a period of 9
minutes. The mixture is heated under reflux conditions for 35 minutes.
~2~9141
-15-
Toluene (51 parts) is added to the mixture which is then heated for an
additional 3 hours 15 minutes under reflux conditions. 70% methane sulfonic
acid (3 parts) is added dropwise over a period of 3 minute. The mixture is
heated under reflux conditions for 3 hours 15 minutes. 70% methane sulfonic
acid (3.9 parts) is added dropwise over a period of 12 minutes. The mixture
is heated at 150-152C for 3 hours 45 minutes. Aminopropyl morpholine (14.3
parts) is added to the mixture dropwise over a period of 15 minutes. The
mixture is maintained at a temperature of 149-150C for an additional 30
minutes. The mixture is stripped at 140C and 100 mm. Hg. The mixture is
cooled to 50C. Mineral oil (338 parts) and diatomaceous earth (19 parts) are
added to the mixture. The temperature of the mixture is maintained at 100-
105C for 1.5 hours and then filtered through additional diatomaceous earth
(18 parts) to yield the desired product.
The nitrogen-containing esters of this invention can be effec-
tively employed in a variety of lubricating compositions based on diverse
oils of lubricating viscosity such as a natural or synthetic lubricating oil, orsuitable mixtures thereof. The lubricating compositions contemplated
include principally crankcase, lubricating oils for spark-ignited and com-
pressionignited internal combustion engines including automobile and truek
engines, two-cycle engine lubricants, aviation piston engines, marine and
railroad diesel engines, and the like. However, automatic transmission
fluids, trans-axle lubricants, gear lubricants, metal-working lubricants,
hydraulic fluids, and other lubricating oil and grease compositions can
benefit from the incorporaion of the present additives.
Natural oils include animal oils and vegetable oils (e.g., castor
oil, lard oil) as well as solvent-refined or acid-refined mineral lubricating
oils of the paraffinic, naphthenic, or mixed paraffin-naphthenic types. Oils
of lubricating viscosity derived from coal or shale are also useful base oils.
Synthetic lubricating oils include hydrocarbon oils and halo-substituted
hydrocarbon oils such as polymerized and interpolymerized olefins (e.g.,
polybutylenes, polypropylenes, propylene-isobutylene copolymers, chlorin-
ated polybutylenes, etc.); alkyl benzenes (e.g., dodecylbenzenes, tetradecyl-
benzenes, dinonylbenzenes, di-(2-ethylhexyl) benzenes, etc.); polyphenols
~2~9~41
-16-
(e.g., biphenyls, terphenyls, etc.); and the like. Alkylene oxide polymers and
interpolymers and derivatives thereof where the terminal hydroxyl groups
have been modified by esterification, etherification, etc., constitute another
class of known synthetic lubricating oils. These are exemplified by the oils
prepared through polymerization of ethylene oxide or propylene oxide, the
alkyl and aryl ethers of these polyoxyalkylene polymers (e.g., methylpolyiso-
propylene glycol ether having an average molecular weight of 1000, diphenyl
ether of polyethylene glycol having a molecular weight of 500-1000, diethyl
ether of polypropylene glycol having a molecular weight of 1000-1500, etc.)
or mono- and polycarboxylic esters thereof, for example, the acetic acid
esters, mixed C3-Cg fatty acid esters, or the C13 Oxo acid diester of
tetraethylene glycol. Another suitable class of synthetic lubricating oils
comprises the esters of dicarboxylic acids (e.g., phthalic acid, succinic acid,
maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic
acid, linoleic acid dimer, etc.) with a variety of alcohols (e.g., butyl alcohol,
hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, pentaerythritol, etc.).
Specific examples of these esters include dibutyl adipate, di(2-ethylhexyl)-
sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diiso-
decyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, the
2-ethylhexyl diester of linoleic acid dimer, the complex ester formed by
reacting one mole of sebacic acid with two moles of tetraethylene glycol
and two moles of 2-ethyl-hexanoic acid, and the like. Silicon-based oils such
as the polyalkyl-, polyaryl-, polyalkoxy-, or polyaryloxy-siloxane oils and
silicate oils comprise another useful class of synthetic lubricants (e.g.,
tetraethyl-silicate, tetraisopropyl-silicate, tetra-(2-ethylhexyl)-silicate,
tetra-(4-methyl-2-tetraethyl)-silicate, tetra-(p-tert-butylphenyl)-silicate,
hexyl-(4-methyl-2-pentoxy)-di-siloxane, poly(methyl)-siloxanes, poly-
(methylphenyl)-siloxanes, etc.). Other synthetic lubricating oils include
liquid esters of phosphorus-containing acids (e.g., tricresyl phosphate, tri-
octyl phosphate, diethyl ester of decane phosphonic acid, etc.), polymeric
tetrahydrofurans, and the like.
Of the various lubricants, crankcase lubricants and automobile
transmission fluids are especially adapted to the improvement by the use of
~2~9141
the additives of the present invention. Generally, the lubricant composi-
tions of the present invention contain an amount of the nitrogen-containing
esters of the invention sufficient to provide such lubricant compositions
with pour point depressant properties. This amount may be as low as 0.01%,
although it more often is from about 0.1% to about 10% preferably about
0.1% to about 1% by weight of the finished lubricant. Higher concentrations
may be employed.
As indicated previously, the nitrogen-containing esters of the
present invention are particularly suitable for imparting pour point depress-
ant properties to lubricants. In this regard, the nitrogen containing esters
reduce the lowest temperature at which the lubricant composition to which
they are added flows. Accordingly, these nitrogen-containing esters extend
the versatility and lubricating qualities of such lubricant compositions at
lower service temperatures. The pour point depressants provided in
accordance with the present invention are especially important for use in
crankcase oils and gear oils as well as automatic transmission fluids and
hydraulic oils.
The nitrogen-containing esters of Examples 2, 3 and 6-11 were
subjected to ASTM Pour Point of Petroleum Oils D 97-66 for determination
of respective initial pour points, and to Method 201-Federal Test Method
Standard No. 791B for determination of respective stable pour points.
Additionally, for purposes of comparison samples A and B tthe preparation
of which is indicated below) were also subjected to these tests. The results
of these tests are indicated in Table I below.
Samples A and B are prepared in accordance with the teachings
of U.S. Patents 3,702,300 and 3,933,761 as follows:
Sample A
A styrene-maleic interpolymer is obtained by preparing a solu-
tion of styrene (536 parts) and maleic anhydride (505 parts) in toluene (7585
parts) and contacting the solution at 99-101C and 480-535 mm. Hg. absolute
with a mixture of benzoyl peroxide (1.55 parts) and toluene (51.6 parts) for
1.5 hours. Mineral oil (2228 parts) is added to the mixture which is
maintained at a temperature of 99-101C and a pressure of 480-535 mm. Hg.
lZ~)9141
--18--
for 4 hours to strip the mixture. To 3888 parts of the stripped mineral oil-
interpolymer slurry there are added mineral oil (77 parts, Alfol 1218 (1380
parts), Alfol 810 (244 parts), n-butanol (133 parts) premixed with 66 Baume
sulfuric acid (2.58 parts) and an additional amount of 66 Baume sulfuric
acid (15.5 parts). The mixture is then heated at 150-160C for 20 hours
whereupon water is distilled off. An additional amount of sulfuric acid (2.58
parts) together with an additional amount of n-butanol (133 parts) is added
and esterification is continued until 95% of the carboxy radicals of the
polymer have been esterified. To the esterified interpolymer there is then
~4 added aminopropyl morpholine (74.8 parts), Ethyl Antioxidant 733~8.4 parts)
and the resulting mixture is heated to 150-160C/10 mm. Hg. to distill off
toluene and any other volatile components. The stripped product is mixed
with an additional amount of mineral oil (600 parts) and filtered. The
filtrate is a mineral oil solution of a nitrogen-containing mixed ester.
Sample B
A styrene-maleic interpolymer is obtained by preparing a solu-
tion of styrene (536 parts) and maleic anhydride (505 parts) in toluene (7610
parts) and contacting the solution at 99-101C and 480-535 mm. Hg. absolute
with a catalyst solution prepared by dissolving Percadox 16W-70~1.79 parts),
a product of Noury Chemical identified as a peroxide catalyst and toluene
(55.2 parts). Mineral oil (4125 parts) is added to the mixture while the
solvent mixture is being distilled off at 99-101C and 480-535 mm. Hg.
absolute. To the mixture of copolymer (1000 parts), mineral oil (4125 parts)
and toluene ~441 parts) there are added Neodol 45 (690 parts), Alfol 1218 (690
parts), Alfol 810 ~244 parts), mineral oil (83 parts), 66 Baume sulfuric acid
(19.3 parts), and a mixture of 66 Baume sulfuric acid (5.52 parts) and n-
butanol (133 parts). The mixture is heated at 150-160C for 20 hours. An
additional amount of 66 Baume sulfuric acid (5.52 parts) together with an
additional amount of n-butanol (133 parts) is added and the esterification is
continued until 95% of the carboxy radicals of the polymer have been
esterified. To the esterified interpolymer, there is then added aminopropyl
morpholine (77.2 parts) and Ethyl Antioxidant 733 (11.4 parts) and the
~rQJe ma ~5
~2~9141
--19--
resulting mixture '.s heated to 150-160C/10 mm. Hg. to distill off toluene and
any other volatile components. The stripped product is mixed with an
additional amount of mineral oil (800 parts) and filtered. The filtrate is a
mineral oil solution of a nitrogen-containing mixed ester.
In the pour point tests identified in Table I below, each of the
nitrogen-containing esters of Examples 2, 3 and 6-11 along with Samples A
and B were mixed with a base oil, viscosity index improver and dispersant in
the amounts identified in Table I. In Table I the following abbreviations are
used for the viscosity index improvers, dispersants and base oils:
V-l is Paratone 715, a product of Exxon identified as ethylene
propylene rubber.
V-2 is a mixture of diluent oil (91.07 parts), Ortholeum 2035 ~8.80
parts), a product ox! DuPont identified as a lubricant additive, and 2,6-di-
tertiary-butyl-para-cresol (0.13 parts).
V-3 is a mixture of diluent oil (10.85 parts) and the following
composition: diluent oil (87.85 parts), 2,6-di-tertiary-butyl-para-crecol (0.15
parts) and Ortholeum 2052 (12.00 parts), a product of DuPont identified as
ethylene-propylene-diene terpolymer.
V-4 is Shellvis 40~ a product of Shell identified as a styrene
isoprene copolymer viscosity improver.
D-l is Lubrizol 7502il(a product of Lubrizol Corporation identified
as a dispersant containing a mixture of succinimides and esters.
D-2 is Lubrizol 7802 a product of Lubrizol Corporation identified
as a dispersant containing a mixture of esters, amides, and imides.
D-3 is Lubrizol 7515A, a product of Lubrizol Corporation identi-
fied as a dispersant containing a mixture of succinimides and esters.
QS is an abbreviation for base stock provided by Quaker State
and OK is an abbreviation for base stock provided by Oljekonsumenternas
Forbund K-fabriken. The expressions 10W40 and 10W30 are the grades of
base stocks tested.
real r ks
12~)9141
--20--
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~Z~9141
-23-
The invention also contemplates the use of other additives in
combination with the nitrogen-containing esters of this invention. Such
additives include, for example, auxiliary detergents and dispersants of the
ash-producing or ashless type, corrosion- and oxidation-inhibiting agents,
viscosity improving agents, extreme pressure agents, color stabilizers and
anti-foam agents.
The ash-producing detergents are exemplified by oil-soluble
neutral and basic salts of alkali or alkaline earth metals with sulfonic acids,
carboxylic acids, or organic phosphorus acids characterized by at least one
direct carbon-to-phosphorus linkage such as those prepared by the treatment
of an olefin polymer (e.g., polyisobutene having a molecular weight of 1000)
with a phosphorizing agent such as phosphorus trichloride, phosphorus
heptasulfide, phosphorus pentasulfide, phosphorus trichloride and sulfur,
white phosphorus and a sulfur halide, or phosphorothioic chloride. The most
commonly used salts of such acids are those of sodium, potassium, lithium,
calcium, magnesium, strontium and barium.
The term "basic salt" is used to designate metal salts wherein
the metal is present in stoichiometrically larger amounts than the organic
acid radical. The commonly employed methods for preparing the basic salts
involve heating a mineral oil solution of an acid with a stoichiometric excess
of a metal neutralizing agent such as the metal oxide, hydroxide, carbonate,
bicarbonate, or sulfide at a tempersture above 50C and filtering the
resulting mass. The use of a "promoter" in the neutralization step to aid the
incorporation of a large excess of metal likewise is known. Examples of
compounds useful as the promoter include phenolic substances such as
phenol, naphthol, alkylphenol, thiophenol, sulfurized alkylphenol, and con-
densation products of formaldehyde with a phenolic substance; alcohols such
as methanol, 2-propanol, octyl alcohol, cellosolve, carbitol, ethylene glycol,
stearyl alcohol, and cyclohexyl alcohol; and amines such as aniline, phenyl-
enediamine, phenothiazine, phenyl-beta-naphthylamine, and dodecylamine.
A particularly effective method for preparing the basic salts comprises
mixing an acid with an excess of a basic alkaline earth metal neutralizing
agent and at least one alcohol promoter, and carbonating the mixture at an
elevated temperature such as 60-200C.
12(~9141
Auxiliary ashless detergents and dispersants are so called despite
the fact that, depending on its constitution, the dispersant may upon
combustion yield a non-volatile material such as boric oxide or phosphorus
pentoxide; however, it does not ordinarily contain metal and therefore does
not yield a metal-containing ash on combustion. Many types are known in
the art, and any of them are suitable for use in the lubricants of this
invention. The following are illustrative:
(1) Reaction products of carboxylic acids (or derivatives
thereof) containing at least about 34 and preferably at least about 54 carbon
atoms with nitrogen-eontaining compounds such as amine, organic hydroxy
compounds such as phenols and alcohols, and/or basic inorganic materials.
Examples of these "carboxylic dispersants" are described in British Patent
1,306,529 and in many U.S. patents including the following:
3,163,603 3,351,552 3,541,012
3,184,474 3,381,022 3,542,678
3,215,707 3,399,141 3,542,680
3,219,666 3,415,750 3,567,637
3,271,310 3,433,744 3,574,101
3,272,746 3,4449170 3,576,743
3,281,357 3,448,048 3,630,904
3,306,908 3,448,049 3,632,510
3,~11,558 3,451,933 3,632,511
3,316,177 3,454,607 3,697,428
3,340,281 3,467,668 3,725,441
3,341,542 3,501,405 Re 26,433
3,346,493 3,522,179
(2) Reaction products of relatively high molecular weight
aliphatic or alicyclic halides with amines, preferably polyalkylene poly-
amines. These may be characterized as "amine dispersants" and examples
thereof are described for example, in the following U.S. patents:
3,275,554 3,454,555
3,438,757 3,565,804
(3) Reaction products of alkyl phenols in which the alkyl group
~Z09~4~
contains at least about 30 carbon atoms with aldehydes (especi-
ally formaldehyde) and amines (especially polyalkylene poly-
amines), which may be characterized as "Mannich dispersants".
The materials described in the following U.S. patents are
illustrative:
3,413,347 3,725,480
3,697,574 3,726,882
3,725,277
(4) Products obtained by post-treating the caboxylic,
amine or Mannich dispersants with such reagents as urea,
thiourea, carbon disulfide, aldehydes, ketones, carboxylic
acids, hydrocarbon-substituted succinic anhydrides, nitriles,
epoxides, boron compounds, phosphorus compounds or the like.
Exemplary materials of this kind are described in the following
U.S. patents:
3,036,003 3,282,955 3,493,520 3,639,242
3,087,936 3,312,619 3,502,677 3,649,229
3,200,107 3,366,569 3,513,093 3,649,6~9
3,216,936 3,367,943 3,533,945 3,658,836
3,254,025 3,373,111 3,539,633 3,697,574
3,256,185 3,403,102 3,573,010 3,702,757
3,278,550 3,442,808 3,579,450 3,703,536
3,280,234 3,455,831 3,591,598 3,704,308
3,281,428 3,455,832 3,600,372 3,708,522
(5) Interpolymers of oil-solubilizing monomers such as
decyl methacrylate, vinyl decyl ether and high molecular weight
olefins with monomers containing polar substituents, e.g.,
aminoalkyl acrylates or acrylamides and poly-(oxyethylene)-
substituted acrylates. These may be characterized as "polymeric
dispersants" and examples thereof are disclosed in the following
U.S. patents:
3,329,658 3,666,730
3,449,250 3,687,849
3,519,565 3,702,300
lZ09141
--26--
Extreme pressure agents and corrosion- and oxidation-inhibiting
agents are exemplified by chlorinated aliphatic hydrocarbons such as chlori-
nated wax; organic sulfides and polysulfides such as benzyl disulfide,
bis(chlorobenzyl)disulfide, dibutyl tetrasulfide, sulfurized methyl ester of
oleic acid, sulfurized alkylphenol, sulfurized dipentene, and sulfurized
terpene; phosphosulfurized hydrocarbons such as the reaction product of a
phosphorus sulfide with turpentine or methyl oleate; phosphorus esters
including principiqlly dihydrocarbon and trihydrocarbon phosphites such as
dibutyl phosphite, diheptyl phosphite, dicyclohexyl phosphite, pentylphenyl
phosphite, dipentylphenyl phosphite, tridecyl phosphite, distearyl phosphite,
dimethyl naphthyl phosphite, oleyl 4-pentylphenyl phosphite, polypropylene
(molecular weight 500)-substituted phenyl phosphite, diisobutyl-substituted
phenyl phosphite; metal thiocarbamates, such as zinc dioctyldithiocar-
bamate, and barium heptylphenyl dithiocarbamate; Group II metal phos-
phorodithioates such as zinc dicyclohexylphosphorodithioate, zinc dioctyl-
phosphorodithioate, barium di(heptylphenyl~phosphorodithioate, 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.
Automatic transmission fluids containing esters of the present
invention often contain frictional additives to improve the so-called slip-
stick characteristics. Such additives are exemplified by fatty amines such
as stearylamine and oleylamine, alkoxylated amines such as the reaction
products of amines with ethyleneoxide or propyleneoxide and other deriva-
tives of amines such as the reaction products of an alkoxylated amine with
boric acid or boron oxide. Still other frictional additives are exemplified by
sperm oil, sulfurized sperm oil, stearylamine methyloleate and other oily
agents.
The above-illustrated additives may each be present in lubri-
cating compositions at a concentration ranging from about 0.01% to about
20% by weight. In most instances, they each range from about 0.1% to about
10%.
The nitrogen-containing esters of this invention can be added
lZ~)914~
--27--
directly to the lubricant. Preferably, however, they are diluted with a
substantially inert, normally liquid organic diluent such as mineral oil,
naphtha, benzene, toluene or xylene, to form an additive concentrate.
These concentrates usually comprise about 0.1 to about 80%, more prefer-
ably about 1 or 2.5 to about 3, 5 or 10%, by weight of the nitrogen-containing
ester of this invention and may contain, in addition, one or more other
additives known in the art or described hereinabove. Concentrations such as
15%, 20%, 30% or 50% may be employed.
While the invention has been explained in relation to its pre-
ferred 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.
