ANTIOXIDANT HETEROCYCLIC NITROGENOUS AROMATIC CONTAINING OIL COMPOSITIONS

PRODUITS A BASE D'HUILE CONTENANT DES COMPOSES HETEORCYCLIQUES AROMATIQUES AZOTES A PROPRIETES ANTIOXYDANTES

English Abstract

ANTIOXIDANT HETEROCYCLIC NITROGENOUS
AROMATIC CONTAINING OIL COMPOSITIONS
(D#71,999-F)
ABSTRACT OF DISCLOSURE
Lubricating oil compositions containing antioxidant
mixtures of heterocyclic nitrogenous aromatic compounds de-
rived from uintaite which function to prevent the oxidative
thickening of lubricant oils at high temperatures.
-I-

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A lubricant oil composition resistant to oxidative thickening at
elevated temperatures comprising a mineral lubricating oil of a viscosity
of from 50 to 1000 SUS at 100°F containing from 0.01 percent to 50 percent
by weight of a heterocyclic nitrogenous-containing mixture of a molecular
weight of 140 to 200 derived from uintaite and distilled therefrom by a
procedure that comprises subjecting uintaite to a cracking temperature
within the range of about 885°F. to about 910°F. to yield a fraction boiling
in the range of about 400°F. to 650°F. which is sequentially treated with a
strong non oxidizing mineral acid to form an acid phase and an acid insoluble
organic phase; hydrolyzing said acid phase to provide an acid insoluble
organic fraction and an aqueous fraction; neutralizing the latter aqueous
fraction with a base to yield further organic- and water-containing phases;
and recovering said organic phase comprising said heterocyclic nitrogenous-
containing mixture therefrom.
2. The lubricant oil composition claimed in claim 1 wherein said
organic phase occurring after acid-treatment, hydrolysis, neutralization
and final removal of said water-containing phase therefrom, is desalted,
dried and recovered upon distillation thereof up to a temperature of 580°F.
3. The lubricant oil composition as claimed in claim 1 wherein said
organic phase occurring after acid-treatment, hydrolysis, neutralization
and final removal of said water-containing phase therefrom, is desalted,
dried and the fraction boiling at and below 580°F. removed upon distilla-
tion; and the residue remaining recovered upon distillation above 580°F.
23

4. A lubricant oil composition as claimed in Claim
1 wherein said composition comprises a mineral lubricating
oil and from 0.10 to 10 percent by weight of the said hetero-
cyclic nitrogenous-containing mixture.
5. A lubricant oil composition as claimed in Claim
2 wherein said composition comprises a mineral lubricating
oil and from 0.10 to 10 percent by weight of the said hetero-
cyclic nitrogenous-containing mixture.
6. A lubricant oil composition as claimed in Claim
3 wherein said composition comprises a mineral lubricating
oil and from 0.10 to 10 percent by weight of the said hetero-
cyclic nitrogenous-containing mixture.
7. A lubricating oil as claimed in Claim 1 wherein
said oil includes 0.1 to 5.0 percent of a zinc dithiophos-
phate characterized by the formula:
<IMG>
in which R is a hydrocarbyl radical or a hydroxy substituted
hydrocarbyl radical having from 4 to 12 carbon atoms, 0.5 to
5.0 percent of monohydroxyalkyl hydrocarbyl thiophosphonate
characterized by the general formula:
<IMG>
in which R1is a hydrocarbyl radical having at least 12 car-
bon atoms, R2 and R3 are selected from the group consisting
of hydrogen and monovalent aliphatic hydrocarbyl radicals
containing 1 to 6 carbon atoms and X is sulfur, from 0.5 to
-24-

5.0 percent of an oil-soluble, basic amino nitrogen-contain-
ing addition type methacrylate copolymer derived from an
alkyl methacrylate in which the alkyl radical has from 4 to
20 carbon atoms and dialkylaminoalkyl methacrylate in which
the alkyl radicals have a total of 4 to 8 carbon atoms, said
copolymer containing 0.05 to 3.5 percent by weight of basic
amino nitrogen and having an inherent viscosity of 0.1 to 3.0
and from 0.25 to 5 percent of calcium carbonate overbased
calcium sulfonate having from about 5 to 30 moles dispersed
calcium carbonate per mole of calcium sulfonate and having
a Total Base Number ranging from 100 to 500.
8. A lubricant oil as claimed in Claim 2
wherein said oil includes 0.1 to 5.0 percent of a zinc di-
thiophosphate characterized by the formula:
<IMG>
in which R is a hydrocarbyl radical or a hydroxy substituted
hydrocarbyl radical having from 4 to 12 carbon atoms, 0.5 to
5.0 percent of monohydroxyalkyl hydrocarbyl thiophosphonate
characterized by the general formula:
<IMG>
in which R1is a hydrocarbyl radical having at least 12 car-
bon atoms, R2 and R3 are selected from the group consisting
of hydrogen and monovalent aliphatic hydrocarbyl radicals
containing 1 to 6 carbon atoms and X is sulfur, from 0.5 to
5.0 percent of an oil-soluble, basic amino nitrogen-contain-
ing addition type methacrylate copolymer derived from an
-25-

alkyl methacrylate in which the alkyl radical has from 4 to
20 carbon atoms and dialkylaminoalkyl methacrylate in which
the alkyl radicals have a total of 4 to 8 carbon atoms, said
copolymer containing 0.05 to 3.5 percent by weight of basic
amino nitrogen and having an inherent viscosity of 0.1 to 3.0
and from 0.25 to 5 percent of calcium carbonate overbased
calcium sulfonate having from about 5 to 30 moles dispersed
calcium carbonate per mole of calcium sulfonate and having
a Total Base Number ranging from 100 to 500.
9. A lubricant oil as claimed in Claim 3
wherein said oil includes 0.1 to 5.0 percent of a zinc di-
thiophosphate characterized by the formula:
<IMG>
in which R is a hydrocarbyl radical or a hydroxy substituted
hydrocarbyl radical having from 4 to 12 carbon atoms, 0.5 to
5.0 percent of monohydroxyalkyl hydrocarbyl thiophosphonate
characterized by the general formula:
<IMG>
in which R1is a hydrocarbyl radical having at least 12 car-
bon atoms, R2 and R3 are selected from the group consisting
of hydrogen and monovalent aliphatic hydrocarbyl radicals
containing 1 to 6 carbon atoms and X is sulfur, from 0.5 to
5.0 percent of an oil-soluble, basic amino nitrogen-contain-
ing addition type methacrylate copolymer derived from an
alkyl methacrylate in which the alkyl radical has from 4 to
20 carbon atoms and dialkylaminoalkyl methacrylate in which
-26-

the alkyl radicals have a total of 4 to 8 carbon atoms, said
copolymer containing 0.05 to 3.5 percent by weight of basic
amino nitrogen and having an inherent viscosity of 0.1 to 3.0
and from 0.25 to 5 percent of calcium carbonate overbased
calcium sulfonate having from about 5 to 30 moles dispersed
calcium carbonate per mole of calcium sulfonate and having
a Total Base Number ranging from 100 to 500.
10. A lubricating oil as claimed in Claim 4
wherein said oil includes 0.1 to 5.0 percent of a zinc di-
thiophosphate characterized by the formula:
<IMG>
in which R is a hydrocarbyl radical or a hydroxy substituted
hydrocarbyl radical having from 4 to 12 carbon atoms, 0.5 to
5.0 percent of monohydroxyalkyl hydrocarbyl thiophosphonate
characterized by the general formula:
<IMG>
in which R1 is a hydrocarbyl radical having at least 12 car-
bon atoms, R2 and R3 are selected from the group consisting
of hydrogen and monovalent aliphatic hydrocarbyl radicals
containing 1 to 6 carbon atoms and X is sulfur, from 0.5 to
5.0 percent of an oil-soluble, basic amino nitrogen-contain-
ing addition type methacrylate copolymer derived from an
alkyl methacrylate in which the alkyl radical has from 4 to
20 carbon atoms and dialkylaminoalkyl methacrylate in which
the alkyl radicals have a total of 4 to 8 carbon atoms, said
copolymer containing 0.05 to 3.5 percent by weight of basic
-27-

amino nitrogen and having an inherent viscosity of 0.1 to 3.0
and from 0.25 to 5 percent of calcium carbonate overbased
calcium sulfonate having from about 5 to 30 moles dispersed
calcium carbonate per mole of calcium sulfonate and having
a Total Base Number ranging from 100 to 500.
11. A lubricating oil as claimed in Claim 5
wherein said oil includes 0.1 to 5.0 percent of a zinc di-
thiophosphate characterized by the formula:
<IMG>
in which R is a hydrocarbyl radical or a hydroxy substituted
hydrocarbon radical having from 4 to 12 carbon atoms, 0.5 to
5.0 percent of monohydroxyalkyl hydrocarbyl thiophosphonate
characterized by the general formula:
<IMG>
in which R1 is hydrocarbyl radical having at least 12 car-
bon atoms, R2 and R3 are selected from the group consisting
of hydrogen and monovalent aliphatic hydrocarbyl radicals
containing 1 to 6 carbon atoms and X is sulfur, from 0.5 to
5.0 percent of an oil-soluble, basic amino nitrogen-contain-
ing addition type methacrylate copolymer derived from an
alkyl methacrylate in which the alkyl radical has from 4 to
20 carbon atoms and dialkylaminoalkyl methacrylate in which
the alkyl radicals have a total of 4 to 8 carbon atoms, said
copolymer containing 0.05 to 3.5 percent by weight of basic
amino nitrogen and having an inherent viscosity of 0.1 to 3.0
and from 0.25 to 5 percent of calcium carbonate overbased
-28-

calcium sulonate having from about 5 to 30 moles dispersed
calcium carbonate per mole of calcium sulfonate and having
a Total Base Number ranging from 100 to 500.
12. A lubricant oil as claimed in Claim 6
wherein said oil includes 0.1 to 5.0 percent of a zinc di-
thiophosphate characterized by the formula:
<IMG>
in which R is a hydrocarbyl radical or a hydroxy substituted
hydrocarbon radical having from 4 to 12 carbon atoms, 0.5 to
5.0 percent of monohydroxyalkyl hydrocarbyl thiophosphonate
characterized by the general formula:
<IMG>
in which R1 is hydrocarbyl radical having at least 12 car-
bon atoms, R2 and R3 are selected from the group consisting
of hydrogen and monovalent aliphatic hydrocarbyl radicals
containing 1 to 6 carbon atoms and X is sulfur, from 0.5 to
5.0 percent of an oil-soluble, basic amino nitrogen-contain-
ing addition type methacrylate copolymer derived from an
alkyl methacrylate in which the alkyl radical has from 4 to
20 carbon atoms and dialkylaminoalkyl methacrylate in which
the alkyl radicals have a total of 4 to 8 carbon atoms, said
copolymer containing 0.05 to 3.5 percent by weight of basic
amino nitrogen and having an inherent viscosity of 0.1 to 3.0
and from 0.25 to 5 percent of calcium carbonate overbased
calcium sulfonate having from about 5 to 30 moles dispersed
calcium carbonate per mole of calcium sulfonate and having
a Total Base Number ranging from 100 to 500.
-29-

Description

10~44~
BA~KGR~VND OF INVENTI ON
There exists a constant demand for improved lu~ri-
cating oil compositions at significantly reduced cost. This
demand has had specific impact in the search for antioxidant~
capable of controlling the thickening tendencies of lubricants
and specifically crankcase engine oils at elevated tempera-
tures.
The utilization, as effective antioxidants, of com-
positions recovered in the course of mining natural occurring,
asphalitic type materials well-known and employed commerci-
ally for other applications would render the cost of recover-
ing the latter materials less expensive while providing anti-
oxidants of substantially unparalleled economy.
Thus, the discovery of a motor oil composition con-
taining an effective, valuable and inexpensiv~ antioxidant
lubricant additive produced with comparative ease would
represent a significant advance in the relevant art. This is
parti~ularly true where the recovered compositions require
only minimal and inexpensive treatment to provide antioxidant~
of substantially uniform effectiveness.
.
SUMMARY OF INVENTION
It is accordingly an object of this invention to
provide improved lubricating oil compositions.
It is a further object of this invention to pro- ;
vide lubricant oil compositions containing an antioxidant
suitable for reducing the thickening of engine oils and parti-
cularly crankcase engine oils at high temperatures. ;
- It is an additional object in accordance with this
invention to produce the antioxidant additive from naturally
occurring asphaltites requiring minimal processing prior to
utilization as antioxidant~.
. _ , . . .
.:
.

g~Z
Thus, it has now been discovered that the thickening propensity of
crankcase engine oils under high temperature operating conditions, for exam-
ple, crankcase bulk oil temperatures of 300F. and above, may be alleviated
significantly by incorporation therein of the inexpensive by-products derived
from the mining of the naturally occurring resin, uintaite~ in a mineral oil
base of lubricating viscosity. The foregoing by-products are composed sub-
stantially of heterocyclic amines, including alkyl substituted and unsubsti-
tuted quinolines, pyrroles, indoles and pyridines, it is believed.
Accordingly, the present invention provides a lubricant oil compo-
sition resistant to oxidative thickening at elevated temperatures comprisinga mineral lubricating oil of a viscosity of from 50 tolOOO SUS at 100 F con-
taining from 0.01 percent to 50 percent by weight of a heterocyclic nitrogen-
ous-containing mixture of a molecular weight of 140 to 200 derived from
uintaite and distilled therefrom by a procedure that comprises subjecting
uintaite to a cracking temperature within the range of about 885 F. to about
910 F. to yield a fraction boiling in the range of about 400 F. to 650 F.
which is sequentially treated with a strong non oxidizing mineral acid to form
an acid phase and an acid insoluble organic phase; hydrolyzing said acid phase
to provide an acid insoluble organic fraction and an aqueous fraction;
neutralizing the latter aqueous fraction with a base to yield further organic-
and water-containing phases; and recovering said organic phase comprising
said heterocyclic nitrogenous-containing mixture therefrom.
I~ETAILED DESCRIPTION OF THE INVENTI~N
Specifically, the invention relates to hydrocarbon mineral oil
formulations containing an antioxidant capable of controlling the thickening
tendencies of said formulations, particularly under high temperature operat-
ing conditions, said antioxidant prepared by treatment of uintaite, a natural
resin of the asphaltite type, found particularly in the Uinta Basin of Utah.
More specifically, the antioxidants employed in the practice of the
~ / - 2 -
:D ~
.. .
.

106446Z
invention are deri~ed from uintaite by the following processes:
Uintaite is subjected to cracking temperatures within the range of
885 F. to 910 F.~ and most desirable about 900 F. to yield a fraction boiling
in the range of about 204 Centigrade (C) to about 343 C. [400 Fahrenheit (F)
to 650 F.] and frequently referred to as the ~diesel cut" which, when treated
with a non-oxidizing, strong mineral aeid, for example concentrated sulfuric
aeid, hydrochlorie aeid, phosphorie acid or trichloro-aeetic acid, yields an
acid phase which is readily separated from an accompanying acid-insoluble
organie
:
- 2a -
'~ '

i(~ti44~z
phase. This latter extractive step is accomplished mo~t desir-
ably at or about ambient temperature, particularly where concen-
trated sulfuric acid i8 employed, to avoid hydrolysis to which
the acid phase is thereafter subjected in a separate step pre-
ferably at a temperature within the range of 53C. to 100C.
If hydrochloric acid is employed in the extrac~ion step, no
water is added in the hy~rolysis step. If anhydrous acid i~
used, the acid is diluted to an approximately fifty percent
(50%) solution in water prior to addition to the "diesel cutn.
Hydrolysis results in the formation of a further acid-insol-
uble organic phase and aqueous fraction. The latter fraction
i8 neutralized with a base, illustratively, Emmonia or sodium
hydroxide, to yield an organic fraction and a water-containing
phase. This organic fraction is a concentrated mixture of weak
nitrogenous organic bases having a molecular weight of 140 to
200. This organic phase is substantially water-soluble and
reactive with sulfuric acid, and is referred to hereinafter as
"the broad unrefined fractionn.
Particularly useful in that they assure uniform
properties within even narrower and more preferred parameter~
than the initial broad unrefined fraction are tho6e fractions
of the foregoing product which when desalted, dried and di~-
tilled by conventional techniques are recovered above and below
580F. The desalting step is accomplished using an inert
organic solvent, desirably dioxane, ether or benzene followed
~y filtration; water is then azeotroped out or, alternatively,
a conventional drying agent added, and the solvent sequenti-
ally flashed off.
The exact composition of the broad unrefined frac-
tion, the narrower fraction recovered below 580F., referred
--3-- -

10~;44~i~
to hereinafter as the "distillate", and that fraction re-
covered above 580F., referred to hereinafter as the "high
temperature residuen, is not fully known. Generally, they
are represented, although it is not intended that characteri-
zation be relied upon, as containing heterocyclic nitrogenous
compounds, the heterocyclic ring structures of which are
selected from five and six member rings and mixtures thereof
containing one nitrogen atom and four and five carbon atoms
respectively; the foregoing either unsubstituted; or substi-
tuted with an unsubstituted fused benzene ring, one or morealkyl moieties, a fused alkyl-substituted benzene ring, or
one or more alkyl moieties and said substituted or unsubsti-
tuted fused benzene ring. The fusion, where it occurs, i8
normally in the 2,3-position of the heterocyclic ring. ~he
foregoing heterocyclic compounds are thus predominantly
quinolines, pyrroles, indoles, pyridines, and possibly acri-
dines and condensation products or heterocyclic polymers
thereof in which the foregoing compounds are unsubstituted
and substituted; predominantly alkyl-substituted, it is
believed. Presumably, the broad unrefined fraction, dis-
tillate and high temperature residue contain many of the
nitrogenous compounds which are believed to occur in uintaite
such as the 3-ethylpyridine, 2,3,5-trimethylpyridine, pyri-
dine, condensation products for~ed in the coking step to form
the broad unrefined fraction, pyrrole, 2-methylpyrrole, poss-
ibly l-methylpyrrole, and other lower alkyl-substituted
pyrrole~ and condensation products thereof, described by
J. M. Sugihora and D. P. Sorensen, Journal of the American
Society, vol. 77, pages 963 to 966 (February 20, 1965).
The organic phase de~ignated as the broad unrefined
fraction used in the practice of this invention and recovered
.
-4-
. .
., : , .' . . '~ ' '

lQ64~Z
as described above, prior to desalting, drying or distilla-
tion, has, typically, physical properties recited in Table
I: :
TABLE I
Specific gravity at 77F. 1.0171
at 60F. 1.0226
API gravity 6.9
Distillation Vol. % F. at 760 mm
(ASTM D 158) Start 400
- 10 10 450
533
648
- End point 656 : .
Recovery 93~ .Pensky-Martens flash point, F. 225
. Pour Point, F. 0
. Viscosity, centipoises at 77F. 32
Average molecular weight 185
Total nitrogen, % by weight 7.8 :
- 20 Basic nitrogen, ~ by weight 6.2
Tertiary amine nitrogen, % by weight 5.9
Carbon, % ~y weight 82.8
Hydrogen,% by weight 9.1
. Sulfur, % by weight o 3
Oxygen, % by weight 0 4
~: This fraction, constituting one of the desired
additive products of the invention, will normally retain
a residue of mineral acid salts remaining from the frac- ~
tionation steps discussed hereinabove and used in securing~ .
: 30 the product, for example, sodium sulfate.
The desalted, dried distillate of the foregoing
initial fraction boiling below 580F. ~304 Centigrade ~C)]
is a deep red oil with a characteristic odor, eighty volume
percent of which forms water-soluble salts with fifty per-
cent (50%) sulfuric acid.
--5--

10644~;Z
This distillate is characterized by the physical
properties recited in the following Table II:
TABLE II
Specific gravity at 77F. 0.973
at 60F. 0.979
API gravity 13.0
Distillation Vol. % F. at 760 mm
(ASTM D-158) Start 361
10 44
492
514 : .
~0 532
90 550
End point 579
Recovery 99~
Pensky-Martens flash point, F. 158
., ,~
Pour point, F. below -40
Viscosity, centipoises at 77F. 15
Average molecular weight i85 ~ :
. 20 Water, % by weight 0.52 :~:
Total nitrogen, % by weight 6.88
Basic nitrogen, % by weight 4.66
Sulfur, % by weight 0.289
The residue of heterocyclic compounds boiling
~. above 580F. (304C.) and remaining after removal of the
.. distillate characterized in Table II is composed predomin-
- antly, it is believed, of highly alkylated quinolines and
indoles in addition to heterocyclic polymers formed from
reactive pyridines, quinolines, indoles and pyrroles, as
noted above; that is, those of the foregoing compounds
having a reactive hydrogen in the alpha position. This .
~ residue is characterized by the following physical proper-
`; ties: :
.. . .. - ..: ... .: .
, . . ~ . :, , . .: ~
.

10~i44~Z
TABLE III
Specific gravity at 77F. 1.059
at 60F. 1.064
API gravity 1.4
Distillation Vol. % F. at 760 mm
~ASTM D-158) Start 598
626
643
659
692
go 888
End point Cracked
; Pensky-Martens flash point, F. 360
Pour point, F. ~80
Viscosity, centistokes at 140F. 492
Average molecular weight 280
Water, % by weight 0.34
Total nitrogen, % by weight 6.94
Basic nitrogen, % by weight 3.32
Tertiary amine nitrogen, % by weight 3.31
Sulfur, % by weight 0.68
Uintait0, or gilsonite or uintahite as it is also designated,
its origin, properties, types and methods of recovery and composition
are further described by H. Abraham in Asphalts and Allied Substances,
5th Edition, vol. I, D. von Nostrand Co., Inc., New York, New York,
; pages 250 et seq. (1945); and Encyclopedia of Chemical Technology, 2d ~ `
Edition, Kirk-Othmer, pages 527 to 533 (1966) and the references recited
; therein.
The foregoing fractions have been producedsporadically by the
American Gilsonite Company, Salt Lake City, Utah; the broad unrefined
fraction bearing the trademark GN-lQ3; the distillate bearing the trademark
GN-200; and the high temperature residue bearing the trad~mark GN-201.
:''
- -7
. .
. . .

106446Z
These products, which have been found frequently
heretofore to possess properties lacking in uniformity in
~, .
many of their areas of application, indicate satisfactorily
uniform results when employed as antioxidants as provided
herein.
The uintaite derivative antioxidants prepared
according to the practice of the invention while particularly
useful in crankcase motor oil formulations wherein they per~
mit operation of equipment over wider temperature range~
than would otherwise be feasible have utility as well in
lubricant formulations for gas turbine and hydraulic ~ystems. ~ -
Concentrations in hydrocarbon lubricating oil o~from about 0.01 to about 50 percent by weight of one of the
foregoing uintaite derived mixtures, that is, the broad un-
refined fraction, the distillate or the high temperature
residue are contemplated. In the lubricating oil concentrates
which are formulated for storage and/or transport and are
subsequently blended into additional base oil to form
finished motor oil formulations ~uitable for crankcase use,
the content of the uintaite antioxidant normally ranges from
about ten (10) to about fifty (50) weight percent. Concen-
trations of these antioxidants in the finished motor oil
composition are advantageously within the range of about
one-tenth (0.1) to about ten (10) weight percent.
The nitrogenous antioxidant mixtures of the inven-
tion replace the significantly more expensive conventional
amine antioxidants exemplified by the phenylnaphthyl amines,
; phenothiazine and diphenylamine. Advantageous proportions
of the heterocyclic nitrogenous compositions of the inven-
tion are within the range of 0.1 to 5 percent by weight and
most desirably about 0.5 to 1.5 percent by weight. The
.~ ,
--8--

10644~i~
lubricant compositions of the invention are also fortified
normally with conventional additives such as anti-wear
agents, dispersants, corrosion inhibitors antifoamants and
other standard additives. .
The hydrocarbon mineral oils employed in this in~
vention can be paraffin base, naphthene base, or mixed paraf-
fin-naphthene base distillate or residual oils. The lubri-
cating oil base generally has been subjected to solvent re-
fining to improve its lubricity and viscosity temperature
relationship as well as solvent dewaxing to remove waxy com-
ponents and to improve the pour of the oil. Generally,
mineral lubricating oils have an SUS viscosity at 100F.
between 50 and 1000 may be used in the formulation of the .-
improved lubricants of this invention although the viscosity
range wil usually fall between 70 and 300 SUS at 100F. A ~ .:
blend of base oils can be employed to provide a suitable
base oil for either a single or multigrade motor oil.
: An antiwear agent desirably incorporated in the
: lubricating oil compositions of the invention is zinc dithio-
phosphate characterized by the foxmula:
rRO S
I P-S- Zn
~RO ~
in which R is a hydrocarbyl radical or a hydroxy-substituted
hydrocarbyl radical having from 4 to 12 carbon atoms. The
preferred zinc dithiophosphates are those in which R represents
~- an alkyl radical having from 4 to 8 carbon atoms. Examples
of suitable compounds include zinc isobutyl 2-ethylhexyl di-
thiophosphate, zinc di(2-ethylhexyl) dithiophosphate, zinc
30 i80amyl 2-ethylhexyl dithiophosphate, zinc di(phenoxyethyl)

lO~y4~;~
dithiophosphate, zinc di(2,4 diethylphenoxyethyl) dithiophosphate and
most desirably zinc isopropylmethyl isobutyl carbinyl dithiophosphate.
In general, these compounds are~employed in the oil composition in a
concentration ranging from about 0.1 to 5.0 percent with the preferred
concentration ranging from about 0.5 to 1.5 percent. These compounds
can be prepared from the reaction of a suitable alcohol or mixture of
alcohols with phosphorus pentasulfide. They are illustrated in U.S.
2,344,395 issued to E. W. Cook et al on 3/14/44 and 3,293,181 issued to
F. A. Stuart, et al on 12/20/66.
Most desirable o~ the foregoing is zinc isopropyl methyl
isobutyl carbinol dithiophosphate prepared by reaction of a methyl-
isobutyl-carbinol and isopropanol with phosphorus pentoxide in a mole
ratio respectively of about 2.7:2.3:1Ø
Dispersants which may be included in the compositions of
the invention are the monohydrocarbyl thiophosphonates characterized
by the formula:
X R R
Rl _ P-O-C-C OH
OH H H
in which Rl is a hydrocarbyl radical having at least 12 carbon atoms and
R2 and R3 are selected from the group consisting of hydrogen and monovalent
aliphatic hydrocarbyl radicals containing 1 to 6 carbon atoms, and X is
- predominantly, or normally, sulfur.
Mono-hydroxyalkyl hydrocarbyl thiophosphates can be prepared
by reacting an alkylene oxide, such as ethylene oxide, alkylene carbonates,
such as ethylene carbonate or propylene carbonate, with a hydrocarbyl
. . .
thiophosphonic acid. The reaction of alkylene carbonate with hydrocarbyl
thiophosphonic acid is usually effected in the presence of an alkaline
catalyst, such as potassium carbonate.
-lQ-

~ 64~6~
The hydrocarbyl thiophosphonic acid employed in
preparing the mono-hydroxyalkyl thiophosphate may be repre-
sented by the general formula:
X : .-
.- , .
OH
wherein Rl is a hydrocarbyl radical which may be aromatic
aliphatic or cycloaliphatic in nature and which usually con-
tains 12 or more carbon atoms and X is sulfur or a mixture :
comprising a major proportion of sulfur and a minor propor-
tion of oxygen. The Rlradical in this formula is advantage-
ously a polyolefin radical such as polyisobutylene or poly-
propylene having an average molecu~ar weight between about
250 and 50,000 since such material~ are the preferred
. materials for reaction with P2Ss. The preferred hydrocarbyl
radical is a polybutene radical having a molecular weight
between 500 and 5,000.
The hydrocarbyl thiophosphonic acids of the above
formula are conventionally prepared by the reaction of P2S5
with a hydrocarbon, the reaction mixture consisting of be-
tween about 5 and 40 weight percent P2S5, at an elevated
temperature of between about 100 and 320C. in a non-oxid~z-
ing atmosphere, for example, under a blanket of nitrogen
followed by hydrolysis of the resulting product by contact
with steam at a temperature between about 100 and 260C.
Steam treatment of the P2S5 hydrocarbon reaction product re-
sults in its hydrolysis to form inorganic phosphorus acids
and a hydrocarbyl thiophosphonic acid of the structure shown
above.
The inorganic phosphorus acids are removed from
the hydrolyzed reaction product prior to reaction with
--11--

-- iO~44~Z
alkylene oxide or alkylene carbOnate to form the mono-hydroxyalkyl
- hydrocarbyl thiophosphates. Removal of the inorganic phosphorus acids
from the hydrolyzed product can be effected by the procedures disclosed
in U.S. 2,951,835 issued to H.D. Kluge, et al on 9/6/60 wherein removal
is effected by contact with synthetic hydrous alkaline earth metal
silicates and synthetic hydrous alkali metal silicates respectively.
Inorganic phosphorus acid can also be removed by extraction with
anhydrous methanol as disclosed in U.S. 3,135,729 issued to H.D. Kluge
et al on 6/2/64.
An alkylene oxide is reacted with the hydrocarbyl thiophosphonic
acid in about an equimolar basis in the absence of catalyst to form the
mono-hydroxyalkyl thiophosphonate additives of this invention. The
preparation of this component is fully described in U.S. 3,272,744 issued
to E.F. Schallenberg, et al on 9/13/66.
The preferred thiophosphonates for use herein are mono ( ~-
hydroxyethyl) alkene thiophosphonates, and most desirably mono ( ~-
hydroxyethyl) polybutene thiophosphonate having an average molecular
weight of about 1100. A phosphonate such as the foregoing is normally
' present in the lubricating oil in an amount of about 0.5 to 5.0 weight
20 percent.
Another suitable additive for lubricant composition of the
invention is a calcium carbonate overbased calcium sulfonate component con-
taining from about 5 moles to 30 moles of dispersed calcium carbonate per
mole of calcium sulfonate and having a Total Base Number from about 100 to
500. The preferred overbased calcium sulfonate will have from about 10 to
20 moles of dispersed calcium carbonate per mole of calcium sulfonate.
These overbased substances provide a high level of alkalinity in the
lubricating oil composition useful in combating deleterious action of
. ~ .
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~0~44~Z
corrosive substances as well as providing dispersanc~. The~ are
advantageously present in amounts of between about 0.25 and 5 wt. %.
In general, an overbased calcium sulfonate is prepared by
reacting a calcium sulfonate (derived from the reaction of a natural
or synthetic sulfonic acid having a molecular weight ranging from about
350 to 600 with hydrated lime) with carbon dioxide at an elevated
temperatuTe, 135-160F., for an extended time period of several hours
and under total reflux conditions. Thereafter the reaction mixture is
filtered to recover an approximately 45 percent oil solution of calcium
carbonate overbased calcium sulfonate perscribed above. The preparation
of this component is fully described in U.S. 3,537,996 issued to E.H. Holst,
et al on 11/3/70.
An effective dispersant and viscosity index improving component
also contemplated foT use in the lubricant oils provided herein is a basic
amine-containing addition-type copolymer formed of a plurality of poly-
merizable ethylenically unsaturated compounds, at least one of which is
amino-free and contains from 8 to about 18 carbon atoms in an aliphatic
hydrocarbon chain, preferably predominantly straight chain in nature, and
one of which as it exists in the polymer contains a basic amino nitrogen
20 in the side chain, in an amount by weight of said polymer of 0.05 to 3.5
percent.
It is essential that at least one of the monomeric components
employed in making the polymer should introduce an oil-solubilizing or
oleophilic structure to insure that the polymer is soluble to the extent
of at least 0.1~ by

10~;44~'~
weight in naphthenic or paraffinic lubricating oils. In
- addition, the presence of basic amino groups, either primary,
secondary or tertiary is necessary to impart the unique
sludge dispersing properties which characterize these poly-
mers. The proportion of basic amino nitrogen is best ex-
pressed in weight percent based on the total copolymer and
should be within the range of 0.05 to 3.5 weight percent as
described above. Elaborating on the description provided
hereinabove, introduction of the basic amino nitrogen struc-
ture can be accomplished by the use of at least one monomeric
component containing the amino group or by use of a monomer
containing a group which is reactive, when present in the
polymer, toward ammonia, or primary or secondary non-aromatic
amines. These monomers can also contain oleophilic struc-
tures that will assist in contributing to the requisite oil
solubility. In addition, some of the polymers coming within
the scope of this invention can, without sacrificing either
oil solubility or dispersing properties, include certain
proportions of monomers that do not themselve~ yield oil
soluble polymers.
Most preferred of the~e methacxylate-containing
polymers is the copolymex of butyl, lauryl, stearyl and di-
methylaminoethyl methacrylate wherein the butyl, lauryl,
stearyl and dimethylamino monomers are incorporated in a
weight ratio respectively of 21:53:22:4. It should be
understood, additionally, that lauryl methacrylate monomer
charged to the polymerization reaction frequently contains
about 25 percent to 28 percent by weight of myristyl meth-
acrylate and the stearyl methacrylate monomer includes, by
weight, about 32 percent to 44 percent of cetyl methacrylate
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10~44~z :
and possibly up to 16 percent by weight of lower hydrocarbyl-containing
methacrylates.
Copolymers useful in the practice of the invention can be
prepared by conventional bulk, solutionJ or dispersion polymerization
methods involving known initiators, including oxygen-yielding compounds,
such as benzoyl peroxide, and azo compounds, such as alpha,alpha'-azo-
diisobutyronitrile, The polymerization processes usually are carried
out in an inert atmosphere, e.g. nitrogen or carbon dioxide, at
temperatures ranging from 30C. to 150C., depending on the catalyst
used and generally at temperatures between 50C. and 70C. when alpha,
alpha~-azodiisobutyronitrile is used as catalyst. It is important to
carry the copolymerization substantially to completeness so that no
unpolymerized monomers remain and the proportions of each component in
the final product are essentially those of the original monomer mixture.
The method of preparing these polymers is described in detail in U.S.
2,737,496 issued to W.E. Catlin, et al on 3/16/56.
The above described methacrylate copolymer is employed in the
lubricating oil in a concentration ranging from about 0.5 to 5 percent
with the preferred concentration ranging from about 1 to 4 peTcent.
A suitable anti-foaming agent is a dimethyl silicone polymer
having a kinematic viscosity at 25C. of about 100 centistokes and above.
; A very satisfactory anti-foaming agent for this purpose is prepared by
diluting 10 grams of a dimethyl silicone polymer (1000 centistokes at
25C.) with kerosene to provide a solution of 100 cubic centimeters.
From 0.005 to 0.025 percent by weight of this concentrate is
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10~46Z
generally employed to provide from 50 to 200 parts per million
of the silicone polymer based on the lubricating oil composi-
~ion.
An example of a crankcase lubricant composition for
- u8e herein will comprise a base oil blend such as the fore~
going in an amount of at least 77 weight percent to about 99
weight percent (e.g. 99.05 weight percent) and preferably
about 89 percent (e.g. 89.46 weight percent) and will contain
from about 0.5 to 8 weight percen~ (e.g. 5 weight percent) of
an oil concentrate containing about 35 percent by welght of a
basic amino nitrogen-containin~ ~ddition type of alkyl ester~
of methacrylic acid, that is, butyl, lauryl, stearyl and di-
methyl amino-ethyl methacrylates in approximately 21:53:22:4
weight ratios (as described in U. S. patent 2,737,496); about
0.25 to 5.0 weight percent, for example, 2 weight percent,
~: .
of an oil concentrate containing 50 weight percent of a cal-
cium carbonate overbased calcium sulfonate of a 300 TBN; ~-
about 0.1 to 5, and for example, about 2.5 weight percent of
an oil concentrate containing about 44 percent by weight of ;
a naphthenic lubricating oil of an SUS viscosity of about 100
at 100F. mono( ~ -hydroxyethyl) alkene thiophosphonate and
from about 0.50 to 5 weight percent, illustratively 0.54 ~-~
welght percent, as indicated above, of a heterocyclic nitro-
genous-containing mixture of the invention.
The formulations so described are supplied by
standard procedures to the crankcase of the engine. When the
engine is in operation the oil will attain elevated tempera-
ture~ and, in accordance with the i~vention, the viscosity
increases in the oil, which would occur in the absence of the
. 30 uintaite derivatives of the invention, will be found to be
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10~i446~
significantly alleviated by their presence. Thus, it has
been found that at 100F. from approximately 700 percent to
100 percent reduction in viscosity increase i8 realized by
use of the compositions of the invention at a concentration of
one weight percent in the lubricant blend. The present inven- -
tion is further illustrated by the foll~lwing example:
EXAMPLE
This example illustrates, in comparative test pro-
cedure, the oxidative-thickening resistant properties imparted
to typical crankcase engine lubricating oils under high tem- -
perature operating conditions by the practice of this inven-
tion.
The mixture of the invention, the high temperature
residue, distillate and broad unrefined fraction derived from
uintaite were incorporated individually in lubricant oil com-
positions incorporating, as well, the full complement of
additives shown in Table IV, and tested, as also shown in
Table IV, in a sequence of Runs for terminal viscosity, per-
centage increases in viscosity and the period required before
break, if any. The additives of the invention were incor-
porated in like amounts in each of Runs 1, 2 and 3 in a test
oil formulation designated "Composltion A" and the test re-
sults secured using identical test procedures. A control
Run 4, made for purposes of comparison and the results of
- which also appear in ~able IV, was undertaken under identical
conditions, excluding the additives of the invention~
The test procedure employed in all four runs was
one which correlates the results of field trials with the
thickening properties of motor oils and is designed to simu-
30 late extreme service conditions in a road test. In this
' ~,

10~i446Z
......
test procedure, a 1969 Ford 289-CID V-8 engine was installed
on a dynamometer test stand instrumented to control engine
operating conditions. The engine was modifiea by replacing the
filter housing with a blank plate and by enclosing the engine
oil pan with l-inch thick Fiberglas insulation ~bout the out-
side. The test stand included an intake air temperature con-
trol to maintain a prescribed carburetor inlet air temperature.
The automotive radiator was submerged in a water tank with
. .. . .
means to control the engine jacket temperature. .
After a three and one-half hour break-in, the engine
was operated at the following test conditions:
Oil charge, quarts 4.0
Duration, hours 40
Load, BHP 105+2
Speed, revol~tions per minute 3200+10
Air-fuel ratio about 15:1
. ., - .
Exhaust back pressure, inches mercury 5.0+1.0 ~ ~
,
Temperatures, degrees Fahrenheit
Jacket outlet 230+2
Intake air 115+2
Oil gallery Record (about 315) -~
~ Spark Advance, BTC 32 ~-
; Approximately five gallons of test oil are re-
quired for each run. About 600 gallons of gasoline is used
in each run as fuel.
In this test the oils were runs, as indicated, for
. . .
40 hours of total and continuous testing time with samples
being removed every four hours, and both viscosity and infra-
red nitro-oxidation patterns monitored.
.
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10~ 62
The test lubricant oil, Composition A, incorporated a
blend of mineral oils of lubricating viscosity having the follow-
ing inspection tests:
Gravity API 31.0
Flash COC F. 410
Viscosity, SUS at:
0F. (extrapolated) 7500
100F. 160
; 210F. 44
The lubricant oil included the components and weight
percentages thereof recited in Table IV, as follows:
, .
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1C~644~Z
TABLE IV
Run No. 1 2 3 4
Com~osition percentages of components by weight ~ -
Composition A 91.56 91.56 91056 92.56
Mono (2-hydroxy-
ethyl) polybutene
(1,100 average
mol wt.) thiophos-
phonate 3.00 3.00 3.00 3.00
Basic amino
nitrogen-con- -
taining addi-
tion type
methacrylate
copolymerl 2.00 2.00 2.00 2.00
Zinc isopropyl
methyl isobutyl
carbinyl dithio-
phosphate 1.09 1.09 1.09 1.09
20 Calcium carbonate
overbased calcium
sulfonate2 1.35 1.35 1.35 1.35
Dimethyl Silicone
Antifoamant 100 ppm 100 ppm 100 ppm 100 ppm
High Temperature 1.00
Residue
Distillate - 1.00
Broad Unrefined
Fraction - - 1.00
30 Hours To Break 3
Vis~osity None 37 hrs. None3 27
DIR 5.8 None 29 hrs. None 22
Terminal Viscosity
- at 100F. 713.2 SUS 1371.1 SUS 650.7 SUS 2858.4 SUS
at 210F. 92.80 SUS 125.4 SUS 85.47 ~US 157.1 SUS
%Viscosity Inc.
at 100F. (ter-
minal) 101.7% 408.8% 92.1% 741.4%
lCopolymer of butyl, lauryl, stearyl and dimethyl-
aminoethyl methacrylates in 21:53:22:4 weight ratio. Per-
centages of myristyl, cetyl and other lower methacrylate
monomers are incorporated with the lauryl and stearyl mono-
mers charged.
2Approximately 15 moles of dispersed calcium car-
bonate per3mole of calcium sulfonate, 300 T~N.
No break observed.
4DIR: infra-red nitro-oxidation pattern.
` -20-
.

10644~Z
It will be evident from the foregoing Table IV that
the composition of Run 4, from which the additives of the
invention were excluded, manifested oxidative breaks a~
measured by viscosity and infra-red nitro-oxidation patterns
at about 27 hours and 22 hours respectively. These breaks
are significant in that thickening of the lubricant oil occurs
characteristically very rapidly after these breaks are found
and often lead in commercial practice with many typical lubri-
cant compositions to engine failure. It will be equally
evident that these breaks did not occur under the rigorous
test conditions employed where high temperature residue or
broad unrefined fraction is incorporated in the lubricant
composition; asd occurs where distillate is incorporated
(Run 2) only after the passage of a significantly greater
period of time, i.e. 37 hours and 29 hours respectively, than
is seen in the control of Run 4.
Thus, when additives of the type described are used,
- the times transpiring until an oxidation break occurs (as
measured by either viscosity increase or infra-red nitro-
oxidation patterns) are significantly increased, indicating
clearly the superior performance of criankcase engine oils
incorporating the nitrogenous compositions of the invention
This conclusion is reinforced by the comparison of terminal
viscosities secured in each of the foregoing runs as recited
in Table IV above.
The method of the invention involves operating an
internal combustion reciprocating engine emplo~ing the lubri-
cant oil compositions of the invention.
It will be evident that the terms and expressions
which have been employed are used as terms of description
., ~ .
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106~462
and not of limitation. There is no intention in the u8e Of
æuch terms and expressions of excluding equivalents of the
features shown and described or portions thereof and it is
; recognized that various modifications are possible within the
scope of the invention claimed.
' "
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