Note: Descriptions are shown in the official language in which they were submitted.
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001 -1-
002 FIELD OF THE INVENTION
003 This invention relates to new lubricating oil
004 compositions. More specifically, it relates to new lubricating
005 oil compositions containing antioxidant molybdenum compounds.
006 BACKGROUND O~ THE INVENTION
007 Molybdenum disulfide has long been known as a
008 desirable additive for use in lubricating oil compositions.
009 However, one of its major detriments is its lack of oil
010 solubility. ~olybdenum disulfide is ordinarily finely ground
011 and then dispersed in the lubricating oil composition to impart
012 friction modifying and antiwear properties. Finely ground
013 molybdenum disulfide is not an effective oxidation inhibitor in
01~ lubricating oils.
015 As an alternative to finely grinding the molybdenum
016 disulfide, a number of different approaches involving preparing
017 salts of molybdenum compounds have been tried. One type of
018 compound which has been prepared molybdenum dithiocarbamates.
019 R~e~/resentative compositions are described in U.S. patent
020 3,~12,539, which teaches molybdenum (VI) dioxide dialkyldithio-
021 carbamates; U.S. 3,509,051, which teaches sulfurized oxymolyb-
022 denum dithiocarbamates; and U.S. 4,098,705, which teaches
023 sulfur containing molybdenum dihydrocarbyl dithiocarbamate
024 compositions.
025 An alternative approach is to form dithiophospbates
026 instead of dithiocarbamates. Representative of this type of
027 molybdenum compound are the compositions described in U.S.
028 3,494,866, such as oxymolybdenum diisopropylphosphorodithioate.
029 U.S. 3,184,410 describes certain dithiomolybdenyl
030 acetylacetonates for use in lubricating oils.
031 Braithwaite and Greene in Wear, 46 tl978) 405-432
032 describe various molybdenum-containing compositions for use in
033 motor oils.
034 U.S. Patent 3,349,108 teaches a molybdenum trioxide
035 complex with diethylenetriamine for use as an additive for
036 molten ~teel.
037 ~ussian patent 533,625 teaches lube oil additives
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prepared from ammonium molybdate and alkenylated polyamines.
Another way to incorporate molybdenum compounds in oil
is to prepare a colloidal complex of molybdenum disulfide or
oxysulfides dispersed using known dispersants. United States
patent 3,223,625 describes a procedure in which an acidic
aqueous solution of certain molybdenum compounds is prepared and
then extracted with a hydrocarbon ether dispersed with an oil
soluble dispersant and then freed of the ether. United States
3,281,355 teaches the preparation of a dispersion of molybdenum
disulfide by preparing a mixture of lubricating oil, dispersant,
and a molybdenum compound in water or Cl 4 aliphatic alcohol,
contacting this with a sulfide ion generator and then removing
the solvent. Dispersants noted to be effective in this procedure
are petroleum sulfonates, phenates, alkylphenate sulfides,
phosphosulfurized olefins and combinations thereof.
It has now been found that a lubricating oil additive can
be prepared by combining an acidic molybdenum compound and
certain basic nitrogen-containing compositions.
; According to the invention, there is provided a process
for preparing a molybdenum-containing composition which comprises
combining an acidic molybdenum compound and a basic nitrogen
compound selected from the group consisting of a carboxylic acid
amide, Mannich base, phosphonamide, thiophosphonamide,
phosphoramide, and dispersant viscosity index improvers to form
a molybdenum containing complex. The process if preferably
carried out in the presence of a polar promoter.
Lubricating oil compositions containing the additive
disclosed herein are effective as either fluid and grease
compositions (depending upon the specific additive or additives
employed) for inhibiting oxidation, imparting antiwear and
extreme pressure properties t and modifying the friction proper-
ties of the oil which may, when used as a crankcase lubricant,
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lead to improved mileage for the vehicle being lubricated with
a lubricating oil of this invention.
The precise molecular formula of the molybdenum com-
positions prepared in the process of this invention is not
known with certainty; however, they are believed to be compounds
in which molybdenum, whose valences are satisfied with atoms of
oxygen or sulfur is either complexed by or the salt of one or
more nitrogen atoms of the basic nitrogen containing composition
used in the preparation of these additives.
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The molybdenum compounds used to prepare the additives for com-
positions of this invention are acidic molybdenum compounds. By acidic is
meant that the molybdenum compounds will react with a basic nitrogen compound
as measured by ASTM test D-664 or D-2896 titration procedure. Typically these
molybdenum compounds are hexavalent and are represented by the following
compositions: lybdic acid, ammonium molybdate, sodium molybdate, potassium
molybdate and other alkali metal molybdates and other molybdenum salts such as
MoOC14, MoO2Br2, Mo203C16, molybdenum trioxide or similar acidic molybdenum
compounds. Preferred acidic molybdenum compounds are molybdic acid, ammonium
lybdate, and alkali metal molybdates. Particularly preferred are molybdic
acid and ammonium molybdate.
The polar promoter which is preferably used in the process of this
invention is one which facilitates the interaction between the acidic moly-
bdenum compound and the basic nitrogen compound. A wide variety of such
promoters may be used. Typical promoters are 1,3-propanediol, 1,4-butanediol,
diethylene glycol, butyl cellosolve, propylene glycol, 1,4-butyleneglycol,
methyl carbitol, ethanolamine, diethanolamine, N-methyl-diethanol-amine,
dimethyl formamide, N-methyl acetamide, dimethyl acetamide, methanol, ethylene
glycol, dimethyl sulfoxide, hexamethyl phosphoramide, tetrahydrofuran and
water. Preferred are water and ethylene glycol. Particularly preferred is
water.
While ordinarily the polar promoter is separately added to the
reaction mixture, it may also be present, particularly in the case of water,
as a component of non-anhydrous starting materials or as waters of hydration
in the acidic molybdenum compound, such as (NH4)6Mo7O24.4 H2O. Water may
also be added as ammonium hydroxide.
The basic nitrogen compounds are selected from those having a basic
B nitrogen content as measured by ASTM D-664 or D-2896. It is preferred that
they be oil-soluble. These compositions are selected from -WWiA~
carboxylic acid amides, Mannich bases, phosphonamides, thiophosphonamides,
phosphoramides, dispersant
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viscosity index improvers, and mixtures thereof. These basic
nitrogen containing compounds are described below (keeping in
mind the reservation that each must have at least one basic
nitrogen). Any of the nitrogen-containing compositions may be
after-treated with e.g., boron, using procedures well known in
the art so long as the after-treated product continues to
contain basic nitrogen. These after- treatments are particularly
applicable to succinimides and Mannich base compositions.
Carboxylic amide compositions that are suitable
starting materials for preparing the products of this
invention, are known in the art. Typical of such compounds
are those disclosed in United States patent 3,405,064. These
compositions are ordinarily prepared by reacting a carboxylic
acid or anhydride ester thereof, having at least 12 to about
350 aliphatic carbon atoms in the principal aliphatic chain
and, if desired, having pendant aliphatic groups to render
the molecule oil soluble which is with an amine or a hydrocarbyl
polyamine, such as an ethylene amine, to give a mono or
polycarboxylic acid amide. Preferred are those amides prepared
from (1) a carboxylic acid of the formula R2COOH, where R2
is C12 20 alkyl or a mixture of this acid with a polyisobutenyl
carboxylic ac~d in which the polyisobutenyl group contains
from 72 to 128 carbon atoms and (2) an ethylene amine,
especially triethylene tetraamine or tetraethylene pentaamine
or mixtures thereof.
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Another class of compounds useful for supplying basic
nitrogen are the Mannich base compositions. The Mannich
base compositions are prepared from a phenol or Cg 200
alkylphenol, an aldehyde, such as formaldehyde or formaldehyde
precursor such a para-formaldehyde, and an amine compound.
The amine may be a mono or polyamine and typical compositions
are prepared from an alkylamine, such as methylamine, or an
ethylene amine, such as diethylene triamine, or tetraethylene
pentaamine and the like. The phenolic material may be
sulfurized and preferably in dodecylphenol or a C80 100
alkylphenol. Typical Mannich bases which can be used in this
invention are disclosed in United States patents 3,649,229,
3,368,972, 3,539,663 and 4,157,309. The last specification
discloses Mannich bases prepared by reacting an alkylphenol
having at least 50 carbon atoms, preferably 50 to 200 carbon
atoms with formaldehyde and an alkylene polyamine HN(ANH)nH
where A is a saturated divalent alkyl hydrocarbon of 2 to 6
carbon atoms and n is 1-10 and where the condensation product
of said alkylene polyamine may be further reacted with urea
or thiourea. The utility of these Mannich bases as starting
materials for preparing lubricating oil additives can often be
significantly improved by treating the Mannich base using
conventional techniques to introduce boron into the
composition.
B
71
The phosphoramides and phosphonamides, such as those
disclosed in United States patents 3,909,430 and 3,968,157,
may be prepared by forming oil soluble phosphorus compound
having at least one P-N bond~ They can be prepared, for
example, by reacting phosphorus oxychloride with a hydrocarbyl
diol in the presence of a monoamine or by reacting phosphorus
oxychloride with a difunctional secondary amine and a mono-
functional amine. Thiophosphoramides can be prepared by
reacting an unsaturated hydrocarbon compound containing from
2 to 450 or more carbon atoms, such as polyethylene, poly-
isobutylene, polypropylene, ethylene, l-hexene, 1,3-hexadiene,
isobutylene, 4-methyl-1-pentene, and the like, with phosphorus
pentasulfide and nitrogen-containing compound as defined above,
particularly an alkylamine, alkyldiamine, alkylpolyamine, or
an alkyleneamine, such as ethylene diamine, diethylenetriamine,
triethylenetetraamine, tetraethylenepentaamine, and the like.
Another class of nitrogen-containing compositions
useful in preparing the molybdenum compositions of this
invention includes the so-called dispersant viscosity index
improvers (VI improvers). These VI improvers are commonly
prepared by functionalizing a hydrocarbon polymer, especially
a polymer derived from ethylene and/or propylene, optionally
containing additional units derived from one or more
co-monomers such as
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oo 1 -7 -
002 alicyclic or aliphatic olefins or diolefins. The functionaliza-
003 tion may be carried out by a variety of processes which
ù04 introduce a reactive site or sites which usually has at least
005 one oxygen atom on the polymer. The polymer is then contacted
006 with a nitrogen-containing source to introduce nitrogen-
007 containing functional groups on the polymer backbone. Commonly
008 used nitrogen sources include any basic nitrogen compound,
009 especially those nitrogen-containing compounds and compositions
010 described herein. Preferred nitrogen sources are alkylene
011 amines, such as ethylene amines, alkyl amines, and Mannich
012 bases.
013 Preferred basic nitrogen compounds for use in this
014 invention are succinimides, carboxylic acid amides, and ~annich
015 bases.
016 The process of this invention may be carried out by
017 combining the acidic molybdenum precursor as described above,
018 with a basic nitrogen-containing composition as described above
019 preferably in the presence of a polar promoter. The reaction
020 is ordinarily carried out at atmospheric pressure; however,
021 higher or lower pressures may be used, if desired, using
022 methods that are well-known to those skilled in the art. A
023 diluent may be used to enable the reaction mixture to be
024 eficiently stirred. Typical diluents are lubricating oil and
025 liquid compounds containing only carbon and hydrogen. If the
026 mixture is sufficiently fluid to permit stirring, no diluent is
027 necessary. A diluent which does not react with the molybdenum
028 containing compound is desirable.
029 In the reaction mixture, the ratio of molybdenum
030 compound to basic nitrogen compound is not critical; however,
031 as the amount of molybdenum with respect to basic nitrogen,
032 increases, the filtration of the product becomes more diffi-
033 cult. Since the molybdenum component probably oligomerizes, it
034 is ad~7antageous to add as much molybdenum as can easily be
035 maintained in the composition. Usually the reaction mixture
036 will have charged to it from 0.01 to 2.00 atoms of molybdenum
037 per basic nitrogen atom. Preferably from 0.4 to 1.0, and most
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001 ~-
002 preferably from 0.4 to 0.7, atoms of molybdenum per atom of
003 basic nitrogen is added to the reaction mixture.
004 The polar promoter, which is preferably used, is
005 ordinarily present in the ratio of 0.1 to S0 mols of water per
006 mol of molybdenum. Preferably from 0.5 to 25 and most
007 preferably 1.0 to 15 mols of the promoter is present per mol of
008 molybdenum.
009 The lubricating oil compositions of this invention
010 can be prepared by admixing, by conventional techniques, the
011 appropriate amount of the molybdenum-containing composition
012 with a lubricating oil. The selection of the particular base
013 oil depends on the contemplated application of the lubricant
014 and the presence of other additives. Generally, the amount of
015 the molybdenum containing additive will vary from 0.l05 to 15%
016 by weight and preferably from 0.2 to 10~ by weight.
017 The lubricating oil which may be used in this
018 invention includes a wide variety of hydrocarbon oils, such as
019 naphthenic bases, paraffin bases and mixed base oils as well as
020 synthetic oils such as esters and the like. The lubricating
021 oils may be used individually or in combination and generally
022 have a viscosity which ranges from 50 to 5,000 SUS and usually
023 from 100 to 15,000 SUS at 38C.
024 In many instances, it may be advantageous to form
025 concentrates of the molybdenum containing additive within a
026 carrier liquid. These concentrates provide a convenient method
027 of handling and transporting the additives before their subse-
028 quent dilution and use. The concentration of the molybdenum-
029 containing additive within the concentrate may vary from 0.25
030 to 90% by weight although it is preferred to maintain a con-
031 centration between 1 and 50% by weight. The final application
032 of the lubricating oil compositions of this invention may be in
033 marine cylinder lubricants as in crosshead diesel engines,
034 crankcase lubricants as in automobiles and railroads, lubri-
035 cants for heavy machinery such as steel mills and the like, or
036 as greases or bearings and the like. Whether the lubricant is
037 fluid or a solid will ordinarily depend on whether a thickening
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001 ~9 ~
002 agent is present. Typical thickening agents include polyurea
003 acetates, lithium stearate and the like.
004 If desired, other additives may be included in the lubri-
005 cating oil compositions of this invention. These additives
006 include antioxidants or oxidation inhibitors, dispersants, rust
007 inhibitors, anticorrosion agents and so forth. Also anti-foam
008 agents stabilizers, anti-stain agents, tackiness agents, anti-
009 chatter agents, dropping point improvers, anti-squawk agents,
010 extreme pressure agents, odor control agents and the like may
011 be included.
012 Certain molybdenum products that can be prepared by
013 the process of invention also find utility in making brake
014 lining materials, in high-temperature structural materials, in
015 iron and steel alloys, in cladding materials, in electroplating
016 solutions, as components for electrical discharge machine
017 electrodes, as fuel additives, in making self-lubricating or
018 wear-resistant structures, as mold release agents, in composi-
019 tions for phosphatizing steel, in brazing fluxes, in nutrient
020 media for microorganisms, in making electrosensitive recording
021 material, in catalysts for refining coal, oil, shale, tar
022 sands, and the like or as stabilizers or curing agents for
023 natural rubber or polymers.
024 The following examples are presented to illustrate
025 the operation of the invention and are not intended to be a
026 limitation upon the scope of the claims.
027 Example 1
028 To a 1 liter flask was added 290 grams of a solution
029 of 45% concentrate in oil of the succinimide prepared from
030 polyisobutenyl succinic anhydride and tetraethylene pentaamine
031 and having a number average molecular weight for the polyiso-
032 butenyl group of about 980, 28.8 grams of molybdenum trioxide
033 as a dry powder, 9.6 ml of water and 150 ml of hydrocarbon
034 thinner. The reaction mixture, which was a murky yellow-green
035 suspension, was heated to 65C and held at this temperature for
036 3-1/2 hours. The temperature was then raised to 150C to
037 remove water and held at this temperature for one hour. Then
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00 1 -10 -
002 50 ml of hot hydrocarbon thinner was added and the reaction
003 mixture was filtered through diatomaceous earth. The filter
004 cake was washed with 100 ml of hot hydrocarbon thinner and a
005 light blue residue remained on the filter cake. The reaction
006 mixture was then stripped to 160C at 20 mm Hg to yield a
007 product containing 4.16~ molybdenum, 3.4896 oxygen, and 1.97%
008 nitrogen.
009 Example 2
010 To a l-liter flask was added 290 grams of the
011 succinimide described in Example 1 and 150 ml of hydrocarbon
012 thinner. The mixture was heated to 65C and then 28.8 grams of
013 molybdenum trioxide and 50 ml of water was added. The tempera-
014 ture of the mixture was maintained at 65C for 1/2 hour and
015 then increased to 155C over a period of one hour and main-
016 tained at 155 to 160C for one hour. To this mixture was
017 added 50 ml hydrocarbon thinner and the product was filtered
018 through diatomaceous earth. The filtrate was stripped to 160C
019 at 20 mm Hg to yield 311 grams of product containing 6.18%
020 molybdenum, 4.17% oxygen and 1.94% nitrogen.
021 Example 3
022 To a 3-liter flask was added 1160 9 o~ the succini-
023 mide described in Example 1 and 800 ml hydrocarbon thinner.
024 The temperature of the mixture was increased to 75C and 200 ml
025 water and 116 g MoO3 were added and the mixture was stirred at
026 97C for 3 hours. It was then stripped at 188C. After
027 cooling to 130C, 100 ml hydrocarbon thinner and 25 g diatoma-
028 ceous earth were added and the mixture was filtered through
029 diatomaceous earth and then stripped at 180C and 20 mm Hg.
030 The product contained 5.84% molybdenum and 1.92~ nitrogen.
031 Example 4
032 To a l-liter flask containing 290 g of the succini-
033 mide described in Example 1 and 200 ml hydrocarbon thinner at
034 65C was added 50 ml water and 589 MoO3. The mixture was
035 stirred at reflux for 4.5 hours and then stripped at 198-209C.
03~ The product was diluted with hydrocarbon thinner and then
037 filtered through diatomaceous earth to yield 332 9 of product
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containing 10.1% molybdenum (by X-ray fluorescence), 9.71% molybdenum ~by
neutron activation) and 5.97% oxygen ~by neutron activation).
Example 5
Lubricating oil compositions containing the additives prepared
according to this invention have been tested in a variety of tests. Reported
below are results from certain of these tests which are described as follows.
In the Oxidator B test the stability of the oil is measured by the
time required for the consumption of 1 liter of oxygen by 100 grams of the
test oil at 340F. In the actual test, 25 grams of oil is used and the
results are corrected to 100-gram samples. The catalyst which is used at a
rate of 1.38 cc per 100 cc oil contains a mixture of soluble salts pToviding
95 ppm copper, 80 ppm iron, 4.8 ppm manganese, 1100 ppm lead, and 49 ppm tin.
The results of this test are reported as hours to consumption of 1 liter of
oxygen and our measure of the oxidative stability of the oil.
The anti-corrosion properties of compositions can be tested by their
performance in the CRC L-38 bearing corrosion test. In this test, separate
strips of copper and lead are immersed in the test lubricant and the lubricant
is heated for 20 hours at a temperature of 295F. The copper strip is
weighed and then washed with potassium cyanide solution to remove copper
compound deposits. It is then re-weighed. The weight losses of the two
strips are reported as a measure of the degree of corrosion caused by the
oil.
The copper strip test is a measure of corrosivity toward non-ferrous
metals and is described as ASTM Test Method D-130. Anti-wear properties are
measured by the 4-ball wear and the 4-ball weld tests. The 4-ball wear test
is described in ASTM D-2266 and the 4-ball weld test is ASTM D-2783. The
data for some of the tests run on compositions of this in~ention is reported
in the Table below.
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The formulations tested contained, in neutral oil, 3.5% of a 50%
in oil solution of succinimide, 22 mmols/kg of the molybdenum product being
tested, 20 mmols/kg sulfuri~ed calcium phenate, 30 mmols/kg overbased
magnesium sulfonate, 5.5% viscosity index improver and, if necessary,
additional succinimide to bring the total nitTogen content of the finished
oil to 2.14%.
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TABLE
Product Oxidator ASTM ASTM L-38 D-130
of B, hrs. D-2266, D-2783 Cu, mg Pb, mg
Example mm kg
1 7.7 .39 165 16.3 10.1
; 2 8.0
~ 3 8.5 lA
: 4
I Fortulation tested was 4~ ~t. = Iybdenum oo Found in neutral oil.
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