Note: Descriptions are shown in the official language in which they were submitted.
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~02 FIELD OF THE_INVENTION
003 This invention relates to a process for preparing
004 lubricating oil a~ditives. It also relates to new lubricating
005 oil compositions containing antioxidant molybdenum compounds.
006 BACKGROUND OF T~E 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. Molybdenum 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
014 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 is molybdenum dithiocar-
019 bamates. Representative compositions are described in U.S.
020 patent 3,412,589, which teaches molybdenum (VI) dioxide
021 dialkyldithiocarbamates; U.S. 3,509,051, which teaches
022 sulfurized oxymolybdenum dithiocarbamates; and ~.S. 4,098,705,
023 which teaches sulfur containing molybdenum dihydrocarbyl dithio-
024 carbamate compositions.
025 An alternative approach is to form dithiophosph2tes
926 instead of dithiocarbamates. Representative of this type of
027 molybdenum compound are the compositions described in U.S.
028 3,4g4,866, such as oxymolybdenum diisopropylphosphorodithioate.
029 U.S. 3,184,410 describes certain dithiomolybdenyl
030 acetylacetonates for use in lubricating oils.
031 Braithwaite and Greène in Wear, 46 (1978) 405-432
032 describe various molybdenum-containin~ 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 steel.
037 Russian patent 533,625 teaches lube oil additives
038 prepared from ammonium molybdate and alkenylated polyaminesO
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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 C] 4 aliphatic alcohol, contacting
this with a sulfide ion generator and then removing the solvent.
Dispersants said to be effective in this procedure are petroleum
sulfonates, phenates, alkylphenate sulfides, phosphosulfurized
olefins and combinations thereof.
SUMMARY OF THE INVENTION
It has now been found that a lubricating oil additive
can be prepared by combining an ammonium tetrathiomolybdate,
and a basic nitrogen-containing composition, preferably in the
presence of a polar promoter, to form a sulfur and molybdenum-
containing complex.
Thus this invention provides a process for preparing a
sulfurized molybdenum-containing composition which comprises
reacting ammonium tetrathiomolybdate and a basic nitrogen com-
pound selected fro~ the group consisting of a succinimide,
carboxylic acid amide, hydrocarbyl monoamine, hydrocarbyl
polyamine, Mannich base, phosphonamide, thiophosphoramide,
phosphoramide, hydrocarbon dispersant viscosity index improvers,
or mixtures thereof.
DEI'AILED DESCRIPTION OF THE INVENTION
Lubricating oil compositions containing the additive
prepared as disclosed herein are effective as either fluid and
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grease compositions (depending upon the specific additive or
additives employed) for inhibiting oxidation, imparting antiwear
and extreme pressure properties, and/or modifying the friction
properties of the oil which may, when used as a cranking case
lubricant, lead to improved mileage.
The precise molecular formula of the molybdenum compo-
sitions prepared by 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 compositions.
The molybdenum compound used to prepare the complexes
of this invention is ammonium tetrathiomolybdate, ~NH~)2MoS4.
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m e polar promoter which is preferably used in the process of
this invention is one which facilitates ~he interaction between the ammonium
tetrathiomolybdate and the basic nitrogen compound. A wide variety of such
promoters may be used. Typical promoters are 1,3-propanediol, 1,4-butane-
diol, diethylene glycol, butyl cellosolve (a trade mark for 2-butoxyethanol),
propylene glycol, 1,4-butyleneglycol, methyl carbitol (a trade mark for
diethylene glycol methylether), ethanolamine, diethanolamine, ~-methyl-
diethanolamine, dimethyl formamide, Ni~Rthyl acetamide, dimethyl acetamide,
methanol, ethylene glycol, dimethyl sulfoxide, hexamethyl phosphoramide, and
tetrahydrofuran and water. Preferred are water and ethylene glycol. Par-
ticularly preferred is water.
While ordinarily the ~olar promoter is separately added to the
reaction mixture, it may also be present, particularly in the case of water,
as a ccmponent of non-anhydrous starti~ng materials or as waters of hydration
of the molybdenum compound. Water may also be added as ammonium hydroxide.
The basic nitrogen compound must have a basic nitrogen content as
measured by ASTM D-664 or D-2896. Typical of such compositions are succinim-
ides, carboxylic acid amides, hydrocarbyl monoamines, hydrocarbon polyamines,
Mannich bases, phosphonamides, thiophosphonamides, phosphoramides dispersant
viscosity index improvers, and mixtures thereof. I~hese basic nitrogen contain-
ing ccmpcunds 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., ~oron using procedures well known
in the art so long as the compos~tions continue to contain basic ni-trogen.
m ese after~treabments are particularly applicable to succinimides and Mannich
base compositions.
The mono and polysuccin~mides that can be used to prepare the
lubricating oil additives descri~ed herein are disclosed in numerous references
and are well kno~ in the art. Certain fundamental types of succinlmides and
the related materials encompassed by the term of art "succinimide" are taught
in United States patents 3,219,666, 3,172,892, and 3,272,746.
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The term succim mide is understood in the art to include many of the amide,
imide, and amidine species which are also formed by this reaction. The pre-
domunant product, however, is a succinimide and this term has been generally
accepted as meaning the product of a re~ction of an aIkenyl substituted suc-
cinic acid or anhydride with a nitrogen containing compound. Preferred
succinimides, because of their commercial availability, are -those succinimides
prepared from a hydrocarbyl succ~nic anhydride, wherein the hydrocarbyl group
contains from about 24 to about 350 cæ bon atoms, and an ethylene amine, said
ethylene amines bein~ especially characterized by ethylene diamine, diethylene
triamine, triethylene tetraam~ne, and tetraethylene pentamine. Particularly
preferred æ e those succinimides prepared from polyisobutenyl succinic
anhydride of 70 to 128 carbon atoms and tetraethylene pentaamine or triethy-
lene tetraamine or mixtures thereof.
Also included within the term ~succinimide are the co-oligomers of
a hydrocarbyl succinic acid or anhydride and a poly secondary amine containing
at least one tertiary amino nitrogen in addition to two or more secondary
amino groups. Ordinarily this composition has between 1,500 and 50,000
average molecular weight. A typical compound would be that prepared by
reacting polyisobutenyl succinic anhy~ride and ethylene dipiperazine,
Carboxylic amide compositions are also suitable starting materials
for preparing the products of this invention. Typical of such compounds
are those disclosed in United States patent 3,405,064. These compositions
are ordinarily prepared by reactin~ a carboxylic acid or anhydride or ester
thereof, having at least 12 to a~out 350 saturated aliphatic cæbon atoms
in the principal aliphatic cha~n and, if desired, having sufficient
pendant aliphatic groups ~o render the molecule oil
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soluble with an am me or hydrocarbyl polyamine, such as an eth~lene amine,
to give a mono or polycarboxylic acid amide. Preferred carkoxylic acid
amides may be prepared from one or more carboxylic acids of the formula R2 _
C12 _ 350 alkyl or C12 _ 350 alkenyl, preferably C
alkyl or C12 20 alkenyl, and a hydrocarbyl polyamine, preferably tetra-
ethylene pentamine or triethylene tetraamine.
Another class of compounds which are useful in this invention
are hydrocarbyl monoamines, hydrocarb~on polyamines, preferably of the type
disclosed in United States patent 3,574,576. The hydrocarbyl, which is
preferably alkyl, or olefinic having one or t~o sites of unsaturation,
usually contains from 9 to 350, preferably from 20 to 200 carbon atoms.
Preferred amines are those which are derived, e.g., by reacting polyiso-
butenyl chloride and diethylene triamine, from polyaIkylene polyamines such
as ethylene diamine, diethylene triamine, tetraethylene pentamine and the
like, or 2-aminoethylpiperazine, 1,3-propylene diamine, 1,2-propylene-
diamine and the like.
Another class of compounds supply m~ basic nitrogen are the
M~nnich base compositions. These compositions are prepared frcm a phenol
or alkylphenol, for example Cg 200 alkylphenol, an aldehyde, such as
formaldehyde or formaldehyde precursor such a para-formaldehyde, and an
amine compQund. The amine may be a mono or polyam~ne and typical compo~
sitions are prepared from methylamine, diethylene triamine, or tetraethylene
pentamine and the like. m e phenolic material may ~e sulfurized or un-
sulfurized. Typical Mannich bases which can be used in this invention are
disclosed in United States patents 4,157,309, 3,649,229, 3,368,972,
3,539,663. The last application discloses Mannich bases prepared by reacting
an alkylphenol having at least 50 carkon atoms, preferably 50 to 200 carbon
atoms with formaldehyde and an alkylene polyamine HN(~NH)nH where A is a
saturated divalent alkyl hydrocarkon of 2 to 6 carbon
~S;231S
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 ~ases as starting materials for preparing lubricating oil additives
can often be significantly i~proved by treating the Mannich base using
conventional techniques to introduce boron into the composition.
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Another class of ccmposition useful for preparing the additives
of this invention are the phosphoramides and phosphonamides sueh as those
disclosed in United States patents 3,909,430 and 3,968,157. These compositions
may be prepared by forming a phosphorus ccn~ound having at least one P-N bond.
m ey can be prepared, for example, by reacting phosphorus oxyehloride with
a ~lydrocarbyl 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 reaeting an unsaturated hydrocarbon
campound containing from 2 to 450 or more carbon atams, such as polyethylene,
polyisobutylene, polypropylene, ethylene, l-hexene, 1,3-hexadiene, iso-
butylene, 4-methyl-1-pentene, and the like, with phosphorus pentasulfide and
nitrogen-containing compound as defined akove, particularly an aLkylamine,
alkyldiamine, aIkylpolyamine, or an alkyleneamine, such as ethylene diamine,
diethylenetriamine, triethylenetetraamine, tetraethylenepentaamine, and the
like.
Another class of nitrogen-containing compositions useful in pre-
paring the molybdenum compositions of this invention ineludes the so-called
dispersant viscosity index improvers (VI improvers). These VI improvers
are co~,monly prepared by funetionalizing a hydroearbon polymer, espeeially
a polymer derived from ethylene and/or propylene, and optionally eontaining
additional units frcm one or more co-monomers such as alicyclic or aliphatic
olefins or diolefins. The functionalization may be carried out by a ~ariety
of proeesses which introduce a reactive site or sites which usually has at
least one oxygen atom on the polymer. The polymer is then contacted with a
nitrogen-containing source to introduce nitrogen-containing functional groups
on the polymer backbone. CoEmonly usel nitrogen sources include any basie
nitrogen compound, especially those nitrogen-containing ccmpounds and
compositions deseribed herein. Preferred nitrogen sources are alkylene
amines, aIkyl am~nes, and Mannich kases~
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001 -7-
002 ~referred basic nitrogen compounds for use in this
003 invention are succinimides, carboxylic acid amides, and ~annich
004 bases.
005 The compositions of this invention may be prepared by
006 reacting the ammonium tetrathiomolybdate and basic nitrogen
007 compound, preferably in the presence of a polar promoter,
008 optionally in the presence of an inert diluent.
009 In the reaction mixture, the ratio of molybdenum com-
Q10 pound to basic nitrogen compound is not critical; however, as
011 the amount of molybdenum with respect to basic nitrogen,
012 increases, the filtration of the product becomes more dif~i-
013 cult. Since the molybdenum component probably oligomerizes, it
014 is advantageous to add as much molybdenum as can easily be
015 maintained in the composition. Usually the reaction mixture
016 will have charged to it from 0.01 to 2.00 atoms of molybdenum
017 per basic nitrogen atom. Preferably from 0.4 to l.0, and most
018 preferably from 0.4 to 0.7, atoms of molybdenum per atom of
019 basic nitrogen is added to the reaction mixture.
020 The polar promoter, which is optionally and preferably
021 used, is ordinarily present in the ratio of 0.1 to S0 mols of
022 water per mol of molybdenum. Preferably from 0.5 to 25 and
023 most preferably l.0 to 15 mols of the promoter is present per
024 mol of molybdenum.
025 This reaction is preferably carried out at from a
026 temperature slightly above that at which the reaction mixture
027 becomes solid to refluxO The reaction is ordinarily carried
028 out at atmospheric pressure; however, higher or lower pressures
029 may be used, if desired, using methods that are well-known to
030 those skilled in the ar~. A diluent which does not react with
031 the ammonium tetrathiomolybdate is desirable. Typical diluents
032 are lubricating oil and liquid compounds containing only carbon
033 and hydrogen. The diluent provides a minimum dilution of the
034 reaction mixture to enable the mixture to be efficiently
035 stirred.
036 The lubricating oil compositions containing the
037 additives of this invention can be prepared by admixing, by con-
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002 ventional techniques, the appropriate amount of the molybdenum-
003 containing composition with a lubricatins oil. The selection
004 of the particular base oil depends on the contemplated appli-
005 cation of the lubricant and the presence of other additives.
006 Generally, the amount of the molybdenum containing additive
007 will vary from 0.05 to 15~ by weight and preferably from 0.2 to
008 10% by weight.
009 The lubricating oil which may be used in this
010 invention includes a wide variety of hydrocarbon oils, such as
011 naphthenic bases, paraffin bases and mixed base oils as well as
012 synthetic oils such as esters and the like. The lubricating
013 oils may be used individually or in combination and generally
014 have a viscosity which ranges from 50 to 5,000 SUS and usually
015 from 100 to 15,000 SUS at 38C.
016 In many instances it may be advantageous to form
Q17 concentrates of the molybdenum containing additive within a
018 carrier liquid. These concentrates provide a convenient method
019 of handling and transporting the additives before their subse-
020 quent dilution and use. The concentration of the molybdenum-
021 containing additive within the concentrate may vary from 0.25
022 to gO% by weight although it is preferred to maintain a con-
023 centration between 1 and so% by weight. The final application
024 of the lubricating oil compositions of this invention may be in
025 marine cylinder lubricants as in crosshead diesel engines,
026 crankcase lubricants as in automobiles and railroads, lubri-
027 cants for heavy machinery such as steel mills and the Iike, or
028 as greases for bearings and the like. Whether the lubricant is
029 fluid or a solid will ordinarily depend on whether a thickening
030 agent is present. Typical thickening agents include polyurea
031 acetates, lithium stearate and the like.
032 If desired, other additives may be included in the
033 lubricating oil compositions of this invention. These addi-
034 tives include antioxidants or oxidation inhibitors, disper-
035 sants, rust inhibitors, anticorrosion agen~s and so forth.
036 Also anti-foam agents stabilizers, anti-stain agents, tackiness
037 agents, anti-chatter agents, dropping point improvers, anti-
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squawk agents, extrene pressure agents, odor control agents and the like may
be included~
Certain m~lybdenum products that can be prepared by the process
of invention also find utility in making brake lining materials, in high-
temperature structural materials, in iron and steel alloys, in cladding
materials, in electroplating solutions, as cQmponents for electrical dis-
charge machine electrodes, as fuel additives, in m~*ing self-lubricating or
wf~r-resistant structures, as mold release agents, in com~ositions for
phosphatizing steel, in brazing fluxes, in nutrient media for microorganisms,
in making electr~sensitive recording material, in catalysts for refining
coal, oil, shale, tar sands, and the like or as stabilizers or curing agents
for natural rubber or polymers.
m e following examples are presented to illustrate the operation
of the invention and are ~ot intended to be a limitation upon the scope of
the claims.
Example 1
To a 500 ml flask was added 145 grams of a solution of 45% con-
centrate in oil of the succinimide prepared from polyisobutenyl succinic an-
hydride and tetraethylene pentaamine and having a number average molecular
weight for the polyisobutenyl group of about 980 and 75 ml of hydrocarkon
thinner. The mixture was heated to 75C and then 0.1 mol (26 grams) of
(NH4)2MoS4 in a pulverized state was added to the react;on mixture along with
35 ml of water. A nitrogen atmosphere was maintained in the reaction mix-ture
which was heated at 65C for 45 minutes. The temperature was then increased
to 95C and water was removed. A heavy eYolution of hydrogen sulfide and
ammonia was observed. m e te~perature was increased to reflux at 155C and
maintained for one hour. The m~xture was then filtered through diatamaceous
earth and the filtrate stripped to 160C at 20 mm Hg to yield a product con-
taining 4.78% molykdenum, 4.00% sulfur, and 1.79% oxygen.
Example 2
In the Oxidator B test the stability of the oil ~s
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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 providing 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 *he oil.
The copper strip test is a measure of corrosivity toward non-
ferrous metals and is described as ASThl 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 ASThl D-2266. The data for some of the
tests run on compositions of this invention is reported in the Table below.
The formulation tested was neutral oil containing 3.5%
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001
002 of a 50% solution of succinimide in oil, 22 mmols/kg of the
003 product of Example 1, 20 mmols/kg sulfurized calcium phenate,
004 30 ~mols/kg overbased magnesium sulfonate, 5.5~ vlscosity index
005 improver and, if necessary, additional succinimide to bring the
006 total nitrogen content of the finished oil to 2.14%~
:
s
` TABLE
Product Oxidato~ AST~I D-130
of B, hrs. D-2266,
Example
8 . 6 . 36 2A
'~'. ' . . '' .
