Note: Descriptions are shown in the official language in which they were submitted.
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BORATED HYDROXYL-CONTAINING COMPOSITIONS
AND LUBRICANTS CONTAINING SAME
The invention relates to lubricant and liqui~ fuel
compositions. In particular, it relates to the use of borated
derivatives of hydrocarbyl vicinal diols in liquid fuels and
lubricants to reduce friction and fuel consumption in internal
comoustion engines.
It provides for a liquid fuel or lubricant composition
comprising a major ~mount of fuel or lubricant and a ~riction-reducing
or anti-oxidant amount of a borated hydlocarbyl vicinal diol
containing from 10 to 30 carbon atoms.
Alcohols are well known fGr their lubricity properties when
formulated into lubrioating oils and for their water-scavenging
characteristics when blended into fuels. The use of vicinal
hydroxyl-containing alkyl carboxylates such as glycerol monooleate
have also ~ound wi~ L~ad use a~ hri~;ty additives. U.S. Patent
2,788,326 ~ s~ some of the e~ters suitable ~or the presenb
i~vention, e.g. glyoerol manooleabe, as ~unor ~I~V~ Ls of Jl~hr;~ting
oil c ~ ~;tions. U.S. Patent 3,235,498 ~;~çln~, amon~ other~ the
same es~er as just mentioned, as an additi~e to other oils. u.S.
Patent 2,443,578 teaches esters ~hexein ~he free l~y~xyl is found
in the acld portion, as for ~x~mrl~ in ta ~ ic acid.
The above patents, as are numercus others, are directed to
the use of such esters as additives. Other patents~ such as UOS.
patents 2,798,083; 2,820,014; 3,115,519; 3,282,971; and 3,309;318 as
well as an article by R. R. Barne~ et al. entitled ~Synthetic Ester
Lubricants" in Lubrication En~ineerinq, August, 1975, pp. 454-457,
teach lubricants prepared from polyhydric alcohols and acid containing
no hydroxyl other than those associated with the acid fL!nctioh.
So far as is known, no effort has been made to employ borated
hydrocarbyl vicinal diols as a fuel or lubricant additive. It is
known that borated hydrocarbyl and borated aliphatic diols are known
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F-1263
for other uses. For example, U.S. Patent 3,740,358 teaches
a phenol-aldehyde foamable composition containing a boron
compound, e.g. a material formed by reacting boric acid or
boric oxide with .such aliphatic hydroxyl-cor,taining compound.
It has now been found that boration of these long-chain alkyl
terminal vicinal diols significantly improves frictio~ reducing
properties and imparts an anti-oxidant component to these novel
c- r-~;tions. In addition to the friction-reducing properties
described, the alkyl terminal vicinal diol borate esters possess much
improved solubility characteristics, especially in synthetic fluids,
over those of the non-borated derivatives. These borates are
non-corrosive to copper, possess anti-oxidant and potential
anti-fatigue characteristics. Furthermore, the compositions also have
significantly greater friction-redu~ing ~Lu~tLLies~ higher viscosity
indices and good low temperature characteristics and solubility
characteristics when used in low additive concentrations than do other
known additives.
The hyd¢ocarbyl vicinal diols contemplated for use in this
invention are hydrocarbyl diols having vicinal hydroxyls. They have
the formula:
R~-OH)2
wherein R is a hydrocarbyl group containing 10 to 30 carbon atoms. As
used herein, "hydrocarbyl" includes, but is not limited to decyl,
dodecyl, tetradecyl, pentadecyl, hexadecyl, octadecyl, eicosyl and the
like. R can be linear or branched, saturated or unsaturated with
linear saturated members being preferred to maximize friction
reduction. The two hydroxyl groups can be anywhere along the
hydrocarbyl chain as long as they are on adjacent carbon atoms
(vicinal), but the terminal diols are much preferred.
The vicinal diols can be synthesized using several methods
known to the art such as that described in ~. Am. Chem. Soc., 689 1504
(1946) which involves the hydroxylation of 1 olefins with peracids.
Vicinal diols can also be prepared by the peroxytrifluoroacetic acid
method for the hydroxylation of olefins as described in J. Am. Chem.
Soc., 76, 3472 (1954). Similar procedures can be found in U.S. Pa~nts
2,411,762, 2,457,329 and 2,455,892.
F-1263 3
The diols can also be prepared via catalytic epoxidatiorl of
an appropriate olefin followed by hydrolysis to form the appropriate
vicinal diol.
~ he preferred borated vicinal diols contain 12 to 20 carbon
atoms. Below a carbon number of 12~ friction-reducing properties are
significantly reduced. Above a carbon number of 20, solllhillty
constraints become significant. Preferred are the C14-C17
hydrocarbyl groups in which solubility, frictional characteristics and
other properties are maximized.
Among the diols contemplated for reaction with the boron
compound are 1,2-hexanediol, 1,2-decanediol, 1,2-dodecanediol,
1,2-tetradecanediol, 1,2-pentadecanediol, 1,2-octadecanediol,
1,2-miYed C15-C18-alkarediols and mixtures thereof.
The boronated compound used in this invention can be made
using a single diol or two or more diols. A mixture of diols can
contain fTom about 5% to about 95% by weight of any one diol, the
other diol or diols being selected such that it or they together
comprise from about 95% to about 5% by weight of the mixture. Such
mixtures are o~ten preferred to the single diol.
Reaction with the boron compound of the ~ormula
(RO)xB(OH)y
where R is a Cl to C6 alkyl, x is 0 to 3
and y is 0 to 3, the sum of x and y being 3,
can be performed in the presence of an alcoholic solvent, such as
butanol or pentanol, or a hydrocarbon solvent such as benzene, toluene
or xylene, or mixtures of such solvents. Reaction temperaturcs of
90C to 263C or more can be used, but 110 to 200C is preferred.
Reaction times can be 1 to 24 hours and more. Up to a stoichiometric
amount o~ boric acid can be used, or an excess thereof can be used to
produce a derivative containing from about û.1% to about 10% of
boron. At least 5 to lû% o~ the available hydroxyl groups o~ the diol
should be borated to derive substantial beneficial effect.
Conversely, a stoichiometric excess of boric acid (more than an
equivalent amount of boronating agent compared to diol ~ydroxyl
groups) can also be charged to the reaction medium resulting in a
1~..~.
7~i
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product containing the stated amount of boron. The boronated diols
can also be borated with a trialkyl borate such as tributyl borate9
often in the presence of boric acid. Preferred reaction temperatures
for boration with the borate will range from 180C to 280C. Times
can be from 2 to 12 hours, or more.
As disclosed hereinabove, the borated esters are used with
lubricating oils to the extent of from 0.1% to 10~ by weight of the
total composition. Furthermore, other additives, such as detergents,
anti-oxidants, anti-wear agents may be present. These can include
phenates, sulfonates, succinimides, zinc dithiophosphates, polymers~
calcium and magnesium salts.
The lubricants contemplated for use wi~h the esters herein
~;srlosed include mineral and synthetic hydrocarbon oils of
lubricating viscosity,mixtures of mineral oils and synthetic oils,and
greases from any of these, including mixtures. The synthetic
hydrocarbon oils include long-chain alkanes such as cetanes and olefin
polymers such as oligomers of hexane, octene, decene, and dodecene,
etc. These vicinal diols are especially effective in synthetic oils
formulated using mixtures of synthetic hydrocarbon olefin oligomers
and lesser amounts of hy~LocaIbyl carboxylate ester fluids. The other
synthetic oils, which can be used alone with the borate~ compounds of
this invention, or which can be mixed with a mineral or synthetic
hydrocarbon oil, include (1) fully esterified ester oils, with no ~ree
hydroxyls, sucn as pentaerythritol esters of ,oca~boxylic acids
having 2 to 20 carbon atoms, trimethylolpropane esters of
monoca~oxylic acids having 2 to 20 carbon atoms~ (2) polyacetals and
(3) siloxane fluids. Fspeci~lly useful among the synthetic esters are
those made from polyc2rboxylic acids and monohydric alcohols. More
preferred are the ester ~luids made by fully esterifying
pentaerythritol1 or mixtures thereof with di- and tripentaerythritol,
with an aliphatic monocarboxyl~c acid containing ~rom 1 to 20 carbon
atoms, or mixtures of such acids.
A wide variety of thickening agents can be use~d in the
greases of this invention. Included among the thickening agents are
alkali and alkaline earth metal soaps of fatty acids and fatty
F-1~63
materials having from 12 to 30 carbon atoms per molecule. The metals
are typified by sodium, lithium, calcium and barium. Fatty materials
are illustrated by stearic acid, hydroxystearic acid, steaxin,
cottonseed oil acids, oleic acid, palmitic acid, myristic acid and
hydrogenated fish oils.
Other thickening agents include salt and salt-soap complexes
as calcium stearate acetate (U.S. Patent No. 2,197,263), barium
stearate acetate (U.S. Patent No. 2,564,561), calcium
stearate-caprylateacetate complexes (U.S. Patent No. 2,999,065)~
calcium caprylate-acetate (U.S. Patent No~ 2,999,066), and calcium
salts and soaps of low-, intermediate- and high-molecular weight acids
and of nut oil acids.
Another group of thickening agents comprises substituted
ureas, phthalocyanines, indanthrene, pigments such as perylimides,
pyromellitdiimides, and ammeline.
The preferred thickening gelling agents employed in the
grease compositions are essentially hydrophobic clays. Such
thickening agents can be prepared from clays which are initially
hydrophilic in character, but which have been converted into a
hydrophobic condition by the introduction of long chain hydrocarbon
radicals into the surface of the clay particles; prior to their use as
a component of a grease composition, as, for example, by being
subjected to a preliminary treatment with an organic cationic surface
active agent, such as an onium compound. Typical onium compounds are
tetraalkylammonium chlorides, such as dimethyl dioctadecyl ammonium
chlorlde, dimethyl dibenzyl ammonium chloride and mixtures thereof.
This method of conversion, being well known to those skilled in the
art, is believed to require no further ~;scussion, and does not form a
part of the present invention. More specifically, the clays which are
useful as starting materials in forming the thickening agents to be
employed in the grease compositions, can comprise the naturally
occurring chemically unmodified clays. These clays are crystalline
complex silicates, the exact composition of which is rlot subject to
precise description, since they vary widely from one natural source to
another. ThesP clays can be described as complex inorganic silicates
~87~6
F -1263 -6
such as aluminum silica-tes, magnesiurn silicates, barium silicates, and
the like, containing, in addition to the silicate latticel varying
amounts of cation-exchangeable groups such as sodium. Hydrophilic
clays which are particularly useful for conversion to desired
thickening agents include montmorillonite clays, such as bentonite,
attapulgite, hectorite, illite, saponite, sepiolite, biotite,
vermiculite, zeolite clays, and the like. The thickening agent is
employed in an amount from 0.5 to 30, and preferably from 3 percent to
15, percent by weight of the total grease composition.
l~ The liquid fuels contemplated include liquid hydrocarbon
fuels such as fuel oils, diesel oils and gasolines~and alcohol fuels
such as methanol and ethanol or mixtures of these fuels.
In all reactions described hereinabove, a solvent is
preferred. Solvents that can be used include the hydrocarbon
solvents, such as toluene, benzene, xylene~ and the like, alcohol
solvents such as propanol, butanol, pentanol and the like, as well as
mixtures of hydrocarbon solvents or alcohol solvents and mixtures of
hydrocarbon and alcohol solvents.
EXAMPLE 1
1,2-Hexadecanediol Borate
869 of 1,2-hexadecanedi~l and 2ûûg toluene sclvent was
charged to a 1 liter reactor equipped with agitator, heater and Dean-
Stark tube with condenser. The contents were heated up to 80-90C to
dissolve the diol and approximately 119 boric acid was added. The
mixture was heated up to 155C until water evolution stopped over a
period of about 4 hours. Approximately 9 ml water was removed by
azeotropic distillation. The solvent was removed by vacuum
distillation and the product was filtered at 100C through
diatomaceous earth. The product became waxy after cooling.
It is believed that the borated product included the
following structures:
7~
F - l~ 63
H H
R - C lH2 R - C lH2
B/ and \ B
0/ \0
R - C CH2
where R = C14H29
EXAMPLE 2
1,2-Oodecanediol Borate (High Boron Content)
Approximately 151g o~ 1,2-dodecanediol and 1509 cf toluene
were charged to a 1 liter reactnr eqll;pped with agitator, heater and
3ean~Stark tube with condenser and provision for using a nitrogen
vapor space blanket. The contents were heated up to 75C, and 45g of
boric acid was added. The mixture was heat~d up to 1s5oc over a
period of 5 hou~s until water evolution stopped. The solvent was
removed by vacuum distillation and the product was fi:l.tered hot
through diatomaceous earth. The product was a viscous, clear yellow
fluid.
EXAMPLE 3
1,2 Dodecandiol
Approximately 303g of 1,2-dodecanediol and 2509 of toluene
were charged to a 1 liter reactor equipped as described in Example 2.
The contents were heated up to 70C and 62g of boric aoid was added.
The mixture was heated up to 160C over a period of 6 hours until
water evolution stopped. The solvent was removed by ~acuum
distillation and the product was filtered hot through diatomaceous
earth.
a~
.,~7~
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EXAMPLE 4
1,2-Mixed C15~_18 Alkanediol Borate (High Boron Content)
Approximately 1559 of 1,2-mixed C15-C18 alkanediols and
130g of toluene were charged to a 1 liter reactor equipped as
described in Example 2. The contents were heated up to 65C and 349
of boric acid was added. The mixture was heated up to 160C over a
period of ~ 1/2 hours until water evolution stopped The solvent was
removed by vacuum distillation and the product was filter~d hot
through diatomaceous earth, yielding a white waxy solid after cooling.
EXAMPLE 5
1,2-Mixed Cl ~ 18 Alkanediol Borate
Approximately 2659 of 1,2-mixed C15~C18 alkanediols and
2009 of toluene were cnarged to a 1 liter reactor equipped as
described in Example 2. The contents were heated to 70~C and 42g of
boric acid was added. The mixture was heated up to 155C over a
period of 5 hours until water evolution stopped. The solvent was
removed by vacuum distillation and the product was filtered at 100C
through diatomaceous earth.
The product of the Examples were blended into a fully
formulated 5W-~O synthetic automotive engine oil containing other
additives, such as detergent, clispersant, anti-oxidant and the like
additives and evaluated using the Low Velocity Friction ~pparatus
(LVFA) test.
EVALUATION OF PRO~UCTS
The compounds were evaluated as friction modifiers in
accordance with the following test.
LOW VELOCITY FRICTION APPARATUS
Description
~ he Low Velocity Friction Apparatus (LVFA) is used to measure
the friction of test lubricants under various loads, temperatures, and
sliding speeds. The LVFA consists of a flat SAE 1020 steel surface
(diam. 3.8 cm.) which is attached to a drive shaft and rotated over a
stationary, raised) narrow ringed SAE 1020 steel surface of 51.6 mm2
(area 0.08 in.2). Both surfaces are submerged in the test
lubricant. Friction between the steel surfaces is measured as a
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function of the sliding speed at a lubricant temperature of 121C.
The friction between the rubbing surfaces is measured using a torque
arm-strain gauge system. The strain gauge output, which is calibrated
to be equal to the coefficient of friction, is fed to t~le Y axis of an
X-Y plotter. The speed signal from the tachometer-generator is ~ed to
the X-axis. To minimize external friction, the piston is supported by
an air bearing. The normal force loa~ing the rubbing surfaces is
regulated by air pressure on the bottom of the piston. The drive
system consists o~ an infinitely variable-speed hydraulic transmission
driven by a 373W (1/2 HP) electric motor. To vary the sliding speed,
the output speed of the transmission is regulated by a lever-cam motor
arrangement.
Procedure
The rubbing surfaces and 12-I3 ml of test lubricant are
placed on the LVFAo A 1756 kPa (240 psig~ load is applied, and the
sliding speed is maintained at 12.2 m/s (40 fpm) at ambient
temperature for a few minutes. A plot of coefficients of friction
(Uk) over the range of sliding speeds, 1.5 to l~2 m/s (5 to 40 fpm,
25-195 rpm), is obtained. A minimum o~ three measurements is obtained
for each test lubricant. Then, the test lubricant and specimens are
heated to 121C~ another set of measursments is obtained, and the
system is run for 50 minutes at 121C, 240 psi and 12.2 m/s (40 fpm)
sliding speed. Afterward, measurements of Uk vs. speed are taken at
1756, 2170, 2859 and 3549 kPa (240, }00, 400, and 500 psig). Freshly
polished steel specimens are used for each run. The surface of the
steel is parallel ground to ol to .2 ~m (4-8 mic~oinches).
The data obtained are shown in Table 1. The data in Table 1
are reported as percent reduction in coefficient of friction at two
speeds. The ~riction-re~ ;n~ es~er additi~es ware evalua~ed in a
fully formulated 5W-20 synthetic lubricating oil comprising an
additive package including anti-oxidant, detergent and dis~eIsant.
The oil had the following general characteristics:
Viscosity lOO~C - 6.8cs
Vi~cosity 40C - 36.9 cs
Viscosity Index - 14~
37Z6
F 1263 -1 n-
TABLE l
Friction Test Results Using
Low Velocity Friction Apparatus
Additive% Reduction in Coefficient
Conc. inof Friction in LVFA at
Example Additive Base Blend0.025 m/s0.152 m~s
Base Blend Fully formulated
engine oil --
l Borated 1,2- l 45 30
hexadecanediol 0.5 41 32
0.~5 28 2
Borated 1,2- 2 33 22
dodecanediol l 45 35
~high boron content) 0.5 34 27
eorated 1,2- l 37 27
dodecanediol O.S 37 31
Borated 1~2-mixed
C,~_C1Q alkanediols 2 42 35
(~lgh ~oron content~ 0.5 33 27
Borated 1,2-mixed l 4~ 31
Cl5-Cl8 alkanediols 0.5 40 28
F-1?63
-11-
The results clearly show the borated hydrocarbyl vicinal diol
to be a far superior friction reducerO For example, the use of only
1/2% of Example 5, borated 1,2-mixed C15 C18 alkanediols reduces
the coefficient of friction by 40%/28%.
The products of this invention were tested in a catalytic
oxidation test for lubr'cants, using as the base oil a 200" solvent
paraffinic neutral mineral oil. The test lubricant composition is
subjected to a stream of air bubbled through the composition at a rate
of 5 liters per hour at 163C for 40 hours. Present in the
composition are metals commonly used as materials of engine
construction, namely:
a. 100~6 cm2 (15.6 sq. in.) of sand-blasted iron wire,
b. 5.03 cm (0.78 sq~ in.) of polished copper wire7
c. 5.61 cm2 (0.87 sq. in.) of polished aluminum wire, and
d. 1.08 cm (0.167 sq. in.) of pûlished lead surface.
Inhibitors for oil are rated on the basis of prevention of
oil deterioration as measured by the increase in acid formation or
neutralization number (NN) and kinematic viscosity (KV) occasioned by
the oxidation. The results of the tests are reported in Table 2.
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TABLE 2
Catalytic Oxidation Test
40 Hours ~ 163C
Additive % Increase
Conc. in Viscosity, ~eutralization
Additive Wt. % KV at 100C Number
~ase Oil Only -- 67 3.62
Example 1 1 22 1.96
3 38 1.60
Example 2 0.25 18 1.95
0.5 19 1.71
1 15 1.32
3 4 0.55
Example 3
Example 4 1 11 2.10
3 15 1.89
Example 5 1 13 2.43
3 17 2.~4
The results clearly show the effectiveness of the borates at
controlling viscosity increase and neutralization nu~ber increase
under somewhat severe oxidation conditions.
