JP2957012B2 - Lubricating oil for internal combustion engines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

 TECHNICAL FIELD The present invention relates to an internal combustion engine such as an engine oil of a gasoline vehicle.
The composition of custom lubricating oils,
For lubricating oil for internal combustion engines that can maintain fuel efficiency
It is about. Background Art Atmospheric CO contributes to global warming_TwoTo control the concentration
From the viewpoint of resource saving, gasoline engine oil
Below, simply referred to as engine oil), wear resistance, oxidation
Strong demand for fuel economy in addition to performance such as stability and clean dispersibility
I'm getting started. Normally, engine oils include mineral oil refined from petroleum and α
-Synthetic lubricating oils such as olefin oligomers and esters
In addition, detergent dispersant, antioxidant, antiwear agent, viscosity index
It is constituted by blending additives such as upper agent. Improve fuel efficiency
Is effective to lower the viscosity of the engine oil.
You. However, simply lowering the viscosity increases the boundary lubrication area
And may cause an increase in friction. Therefore, in recent years,
Friction modifier in engine oil to reduce friction in the boundary lubrication region
(FM) has been added. Among friction modifiers
Is an ashless additive such as an ester, amine, or amide
Organometallic additives are more effective than additives. Inside this
As shown in Japanese Patent Publication No. 3-23595,
Dendithiocarbamate (MoDTC) or oxymolybdenum sulfide
Yes, such as ten organophosphorodithioate (MoDTP)
Molybdenum compound is known to have high effect
I have. In addition, MoDTC is compatible with zinc dithiophosphate (ZnDTP).
It is reported that a high friction reduction effect can be obtained when used together.
Have been. However, with the use of engine oil, MoDTC deteriorates
And is consumed. As a result, fuel efficiency is low at the time of new oil
Even with excellent performance, it will save fuel over time.
There was a problem that cost was lost. The solution
It is conceivable to increase the amount of MoDTC added for new oil
You. However, in general, Mo with a relatively short alkyl group
Due to its low solubility, DTC has increased storage stability
Decrease. On the other hand, MoDT having a relatively long alkyl group
C has high solubility but low heat resistance.
It was difficult. Therefore, an object of the present invention is to provide MoDTC using a new manufacturing method.
Therefore, after use for a long time without precipitation before use
Also keep the wear loss of internal combustion engine lubrication oil low,
MoDTC sedimentation, generation of sludge, etc. are kept low.
Internal combustion engine that does not deteriorate in quality even after long-term storage
It is to provide a lubricating oil for use. DISCLOSURE OF THE INVENTION The present inventors have conducted intensive studies in order to achieve the above object.
As a result, the oxymolybdenum sulfide
By using a predetermined amount of bamate,
Life time is significantly improved and after long use and storage
Found that stable use is possible in
Ming has been completed. That is, the lubricating oil for an internal combustion engine of the present invention comprises (a) a mineral oil and / or a synthetic lubricating oil as a base oil, and (b) represented by the following chemical formula (1):₁Is 14 carbon atoms
A branched aliphatic hydrocarbon group as described above, and R_Two~ R_FourIs charcoal
Oxymolybdenum sulfide, which is an aliphatic hydrocarbon group having a prime number of 4 or more
Dendithiocarbamate as molybdenum (Mo)
It contains 0.005 to 0.2% by weight.(Where Χ₁~ Χ₄Is an oxygen atom or a sulfur atom
Each may be the same or different. The lubricating oil for an internal combustion engine according to another aspect of the present invention is
In the lubricating oil, R in the chemical formula (1)₁And R_ThreeIs a branch with 14 or more carbon atoms
An aliphatic hydrocarbon group, and R_TwoAnd R_FourHas 4 or more carbon atoms
Oxymolybdenum dithio sulfide, an aliphatic hydrocarbon group
The amount of carbamate is 0.005 to 0.2 as molybdenum (Mo).
% By weight. Further, another lubricating oil for an internal combustion engine of the present invention comprises: (a) a mineral oil and / or a synthetic lubricating oil as a base oil;₁Has a branch at the β position
An aliphatic hydrocarbon group having 10 or more carbon atoms, and R_Two~
R_FourIs an oxysulfide which is an aliphatic hydrocarbon group having 4 or more carbon atoms
Molybdenum dithiocarbamate, molybdenum (Mo) content
As 0.005 to 0.2% by weight. Another lubricating oil for an internal combustion engine of the present invention is
In the lubricating oil, R in the chemical formula (1)₁And R_ThreeIs a charcoal with a branch at the β-position
An aliphatic hydrocarbon group having a prime number of 10 or more, and R_TwoAnd R_FourIs
Oxymori sulfide, an aliphatic hydrocarbon group having 4 or more carbon atoms
The amount of molybdenum (Mo)
0.005 to 0.2% by weight. Further, another lubricating oil for an internal combustion engine of the present invention is preferably
Further comprises adding zinc dithiophosphate as phosphorus (P) amount of 0.
It contains 0.1 to 0.2% by weight. Further, another lubricating oil for an internal combustion engine of the present invention is preferably
In addition, sulfur-based additives are used as sulfur (S)
It contains 0.01 to 0.5% by weight. Further, another lubricating oil for an internal combustion engine of the present invention is preferably used.
Or a phenol-based oxidation having an ester group.
It contains an inhibitor of 0.2 to 5% by weight. Further, another lubricating oil for an internal combustion engine of the present invention is preferably
Is a compound represented by the formula (1)₁Or R₁And R_ThreeLeads to nitrogen
Carbon at the second to fifth carbon atom from the carbon atom at the chain end
Oxymolybdenum dithioca sulfide having several or more side chains
Includes bamate. BEST MODE FOR CARRYING OUT THE INVENTION [Base oil] The base oil used in the present invention is a mineral oil of a lubricating oil fraction.
Or a synthetic oil, which accounts for the majority of the lubricating oil composition.
The base oil used as the component can be any lubricating base oil.
Can be used. In particular, a favorable friction reduction effect
To obtain a base oil, use a base oil with a viscosity index of 135 or more.
Is preferred. Specifically, mineral oils such as paraffinic crude oil
The fraction obtained by distillation of the atmospheric distillation residue under reduced pressure is
Extraction, hydrorefining, MEK or toluene
Treatment by a treatment method such as solvent dewaxing
Deasphalted lubricating base oil and the residue of the vacuum distillation
Deasphalted oil obtained by the above-mentioned appropriate treatment method
Lubricating base oil, slack wax, etc.
A suitable fraction of the isomerized oil obtained by hydroisomerization
Highly refined base oil obtained by dewaxing MEK or toluene solvent, and
And mixtures thereof. As synthetic oils, α-olefin oligomers
-From dibasic acids such as adipic acid and primary alcohols
Synthesized diester, neopentyl glycol, tri
High alcohol such as methylolpropane and pentaerythritol
Polyols synthesized from alcohol and monobasic acid
Ter, alkylbenzene, polyoxyalkylene glyco
And mixtures thereof. Further
In addition, mixed oils combining appropriate mineral and synthetic oils
It can be used as a base oil. [Sulfated oxymolybdenum dithiocarbamate] The present invention
Oxymolybdenum dithiocarbamate (Mo
DTC) is represented by the following chemical formula (1).(Where Χ₁~ Χ₄Is an oxygen atom or a sulfur atom
Each may be the same or different. Where R₁Or R₁And R_ThreeIs a branched aliphatic having 14 or more carbon atoms
Hydrocarbon group or β-branched C10 or more
It is an aliphatic hydrocarbon group. R₁Or R₁And R_ThreeBut in the beta position
An aliphatic hydrocarbon group having 14 or more carbon atoms having a branch,
In particular, it must be a primary alkyl group in terms of thermal stability.
Is preferred. As the carbon number, use 10 to 36, especially 14 to 24
Preferably. Soluble when carbon number is below this range
Is not sufficient, and beyond this range, the relative molybdenum
Is not preferred because the content of The branch position of this branched aliphatic hydrocarbon group is linked to nitrogen.
A side chain to the second to fifth carbon atom from the carbon atom at the chain end
Having a side chain at the second carbon atom.
(That is, have a branch in β)
No. This is the case when there is a branch at the α-position (such as a secondary alkyl group).
Etc.), and in the case of a straight chain, it is easy to decompose and has stability.
This is because it is not preferable because it is bad. Also a short at the tip
In the case of having a branch, it is almost the same as the case of the straight chain described above
This is because it is not preferable. The side chain is preferably an alkyl group having 1 to 16 carbon atoms, particularly
Is approximately equal to the number of carbon atoms in the main chain, specifically, R₁(Also
Is R_Three) Is n, the carbon number of the side difference is ｛(n
-2) / 2} to {(n-6) / 2}.
New As a preferred example of these, the carbon number of the side difference is
2- (hexyldecyl) group which is {(n-4) / 2},
Butylundecyl group, 2-octyldodecyl group, 2-de
And a siltetradecyl group. Where R₁Or R₁And R_ThreeR other than_Two~ R_FourOr R_TwoWhen
R_FourIs an aliphatic hydrocarbon group having 4 or more carbon atoms,
Preferably 4 to 12 branched aliphatic hydrocarbon groups,
It is a branched alkyl group having a branch at the β-position of carbon water 4 to 10.
Is particularly preferred from the viewpoint of thermal stability. These preferred
For example, 2-ethylhexyl group, 2-methylbutyl
And the like. Here, the aliphatic hydrocarbon group is an alkyl group,
Hydrocarbon groups such as alkyl groups and alkenyl groups are preferred,
Ester group, ether group, alcohol group, carboxyl
And the like. In the formula, 式₁~ Χ
₄Is an oxygen atom or a sulfur atom, preferably
Χ₁~ Χ₄The ratio of oxygen atoms to sulfur atoms is 1/3 to 3/1
is there. The amount of MoDTC added to the total lubricating oil weight is
This is the range to be solved, and is converted to molybdenum (Mo) amount of 0.
005 to 0.2% by weight, preferably 0.02 to 0.15% by weight,
More preferably, it is 0.03 to 0.10% by weight. This addition amount
Is less than 0.005% by weight, the friction reduction effect is small,
%, The effect of reducing friction is saturated.
And costs rise. In addition, four hydrocarbon groups R₁,
R_Two, R_Three, R_FourAre MoDTCs that do not fall within the above range.
You may add in the range which does not prevent a result. Incidentally, oxymolybdenum sulfide dithiocarbamate (Mo
When the structural formula of (DTC) is expressed as follows
There is.  This is CS_TwoDo you interpret the bond between -Mo as Keke structure?
It depends on whether it is interpreted as a heavy bond.
You. Structural formulas are a theoretical problem, and actual structural formulas
Does not change the present invention. [Production method of MoDTC] Generally, oxymolybdenum sulfide
The method for producing thiocarbamate (MoDTC) is disclosed in
(A) molybdenum trioxide as disclosed in
Or alkali metal salts of molybdic acid or aluminum
Salt, (b) alkali hydrosulfide or general formula M_TwoS (M is Al
Alkali sulfide represented by potassium metal or ammonium group)
(C) reacting with (c) carbon disulfide and (d) secondary amine
Those that respond are known. In this case, the secondary amine
By the hydrocarbon group, 4 of molybdenum dithiocarbamate
Two hydrocarbon groups R₁, R_Two, R_Three, R_FourIs determined. Secondary amine
Can be produced by using an alkyl halide and an ammonium halide.
Reaction with a or primary amine, alcohol and primary amine
Reaction with is known. However, MoDTC used in the present invention is
One of the two hydrocarbon groups to be bonded has a long chain, for example, a carbon number
14 or more, the other is a short chain, for example, having 10 or less carbon atoms
(Hereinafter also referred to as partial length difference MoDTC). Such a partial length
Synthesis of differential MoDTCs is difficult for the following reasons. In order to synthesize partial long-chain MoDTC, the corresponding
A secondary amine is required. The secondary amine synthesis method
With alkyl halides and alcohols and ammonia
When the amine is synthesized by reacting
Primary amines and tertiary amines are also included, and their hydrocarbons
Groups can be combined with long and short chains in addition to combining long and short chains.
And combinations of short chains and short chains. In addition, the second grade
Purification of olefins is carried out using relatively few carbon atoms,
If is less than 16, distill the secondary amine of the desired structure
It is also possible to purify by such as. But relatively
High carbon number, for example, the sum of carbon number is 18 or more, especially 22 or less
The above secondary amine has a high boiling point and a small boiling point difference.
Therefore, isolation becomes difficult. Therefore, the target part
It is difficult to efficiently produce long-chain MoDTC. Therefore, in the production of partially long-chain MoDTC,
MoDTC by-product whose structure is different from the target
In order to obtain the desired MoDTC with high purity and high yield, (a)
Has a halogen, hydroxyl, sulfonic or nitro group
Amine derived from a hydrocarbon derivative and a primary amine
(B) the secondary amine, a metal source, and
・ Produce a partially long-chain MoDTC by reacting
It is preferable to make them. According to this production method, the hydrocarbon group of the hydrocarbon derivative
Part and the hydrocarbon group of the primary amine have the respective structures
The secondary amine having the required structure is
Can be obtained without by-producing amine. Use this as raw material
To efficiently produce partially long-chain MoDTCs
Can be. In this production method, carbonization as a raw material of a secondary amine
Hydrogen derivatives include halogen, hydroxyl group, sulfonic acid
Group or a group having a nitro group substituent is used
You. Because the reaction is easy, alkyl halide
Preferably, it is used. As the alkyl halide,
Fluoride, chloride, bromide, iodide
Although the recuperation is improved, chlorides are better in terms of ease of handling.
Good. As a preferred compound, 2-hexyldecyl
Loride, 2-heptylundesyl chloride, 2-octyl
Ludodecyl chloride, 2-decyltetradecyl chloride
And a chlorinated product having a branched alkyl group. The primary amine used in this production method is 2-ethylhexyl.
Branched alkyl such as silamine and 2-methylbutylamine
Amines having a hydroxyl group are preferred. Alkyl primary amine
The carbon number of the alkyl group is greater than the carbon number of the alkyl derivative.
Less is from the time when primary amines are easy to purify
preferable. In this production method, the secondary amine is
Obtained by reacting a hydrogen derivative with a primary amine. Halogenation
When using the reaction of alkyl and alkyl primary amine
Is the molar ratio of alkyl halide to alkyl primary amine
Is 1: 1 to 1: 5, especially 1: 1.2 to 1: 4.
The reaction temperature is 50 to 250 ° C, especially 150 to 200 ° C.
It is preferable in terms of yield and reaction efficiency. As a solvent during the reaction
Use solvents such as halides and hydrocarbons as appropriate.
However, the reaction proceeds without using a solvent. Anti
After the reaction, unreacted raw materials are removed by distillation, etc.
However, even if the step of removing the by-product amine
Good. In this production method, MoDTC is a metal source, sulfur and carbon source.
And secondary amine in aqueous solution or organic solvent
Combined by In the reaction in an aqueous solution, the pH is 1 to
13, particularly preferably 1.5 to 3.5, if necessary sulfuric acid, salt
Add an acid such as an acid. The reaction temperature is between 60 ° C and 11 ° C, especially
95 ° C to 105 ° C is preferred. Molar ratio of secondary amine to metal source
Is preferably from 1: 0.8 to 1: 3, particularly preferably from 1: 0.9 to 1: 2.5. Money
If the source is excessive, removal of unreacted materials is complicated.
Become. After removing the solvent after the reaction, absorb silica gel or the like.
Purification of the dithiocarbamate by the adhesive is not possible.
Is it a point of removing pure substances, especially improving properties as a lubricant additive?
Are preferred. Also, N, N'-dimethylformamide, etc.
Can also be synthesized in an organic solvent. The metal source used in the above synthesis depends on the solvent used during the reaction.
A variety of solvable metal compounds can be used. Mo
In the case of DTC, molybdenum trioxide and molybdic acid
Potassium metal salts, ammonium salts of molybdic acid, etc.
Can be used as a source. In addition, metal source and second class
As sulfur and carbon source to react with amine, sodium sulfide
Alkali sulfide such as lithium, ammonium sulfide, hydrosulfide
Combined with sulfides such as sodium bisulfide such as sodium
Preferably, carbon is used. The method for producing the partial long-chain MoDTC described above is based on molybdenum
Can be used for other dithiocarbamates.
You. Dithiocarbamate is generally represented by the following chemical formula (2)
Is represented by In the formula, M is molybdenum, tungsten, titanium, lead,
Metal elements such as zinc and copper, and R and R 'have different structures
It is a hydrocarbon group such as an alkyl group and an aryl group. What
The bonding type between the metal element and sulfur depends on the metal element.
May be different. Usually, carbon number of hydrocarbon group R, R '
Is preferably from 4 to 28. Dithiocarbamate is lubricated
Good as a vulcanization accelerator for oil additives, latex and rubber.
It is used well. This production method comprises the steps of producing a hydrocarbon group R, R '.
Is preferred when the sum of the carbon numbers of the
And the hydrocarbon groups R and R 'are alkyl groups,
Is preferably used in the case of a branched alkyl group. [Zinc dithiophosphate] A diamine represented by the following chemical formula (3)
It is preferable to further add zinc thiophosphate (ZnDTP).
New Where R₁₁~ R₁₄Is a straight chain having an average carbon number of 3 or more;
Or a hydrocarbon such as a branched alkyl or aryl group
Elementary group. R₁₁~ R₁₄Is a C 3 -C 18
A kill group is preferred, specifically, a propyl group, butyl
Group, pentyl group, hexyl group, octyl group, lauryl group
And the like. R₁₁~ R₁₄May be the same,
It may be different. The amount of ZnDTP added to the total lubricating oil weight is phosphorus (P)
0.01 to 0.2% by weight based on the amount, especially 0.04 to 0.2%
% By weight, and most preferably 0.04 to 0.15% by weight.
Good. In this range, high due to the synergistic effect with MoDTC
Abrasion prevention performance is obtained, and phosphorus content exceeds 0.2% by weight
Has a large adverse effect on the exhaust gas catalytic activity. [Sulfur-based additive] Add sulfur-based additive
Is preferred. As sulfur additives, sulfurized oils and fats
, Sulfides, thiocarbonates, metal dithioca
Extreme pressure agents such as rubamate can be used. Concrete
Specifically, sulfurized pepper oil, sulfurized pinene oil, sulfurized soybean oil,
Sulfurized polyolefin, dialkyl disulfide, dia
Lucyl polysulfide, dibenzyl disulfide,
Ditertiary butyl disulfide, polyolefin poly
Resulfide, bisalkyl polysulfanyl thiazi
Azole, sulfurized phenol, zinc, lead, antimony, etc.
Metal dithiocarbamate is used. In particular, dithiocarbon chloride represented by the following chemical formula (4)
Bamate (ZnDTC) or a thiocyanate represented by the following chemical formula (5)
Odiazole type polysulfide compound can be used
preferable. Where R_{twenty one}~ R_{twenty four}Is an alkyl group having an average of 6 or more carbon atoms,
Cycloalkyl group, aryl group, alkylaryl group,
With hydrocarbon groups such as arylalkyl groups and alkenyl groups
Yes, ester group, ether group, alcohol group, carbo
It may contain a xyl group or the like. Preferably, average charcoal
An alkyl group having a prime number of 8 to 18 is used. Specifically, 2-
Ethylhexyl group, isotridecyl group, octadecyl group
(Stearyl group) and the like. Usually R_{twenty one}~ R_{twenty four}Is
The same structure is used, but the average number of carbon
If it is a fixed value, ZnDTCs with different structures may be mixed.
No. In addition, metal DTC such as lead other than zinc is used for engine oil.
Part of the fuel is burned and emitted into exhaust gas,
Not preferred. Where R₃₁, R₃₂Is an alkyl group having an average of 3 or more carbon atoms,
Cycloalkyl group, aryl group, alkylaryl group,
Hydrocarbon groups such as arylalkyl and alkenyl groups
Yes, ester group, ether group, alcohol group, carbo
It may contain a xyl group or the like. Preferably, average charcoal
An alkyl group having a prime number of 3 to 18 is used. Specifically, Ok
Examples include a tyl group, a nonyl group, and a dodecyl group. Through
Always, R₃₁, R₃₂Have the same structure but their carbon
If the average value of the numbers is a predetermined value, the polysales of different structures
Fide compounds may be mixed. x and y are 2 to 5
Yes, usually 2-3 are used. The amount of sulfur-based additive to the total lubricating oil weight is
0.01 to 0.5% by weight in terms of sulfur (S)
Preferably 0.05 to 0.4% by weight, more preferably 0.07 to 0.3%
% By weight, and when the added amount is less than 0.01 to less than% by weight.
The effect of prolonging the service life is small.
Even the desired effect saturates. Note that MoDTC and R_{twenty one}~ R_{twenty four}of
When ZnDTC with an average carbon number of less than 6 coexists in lubricating oil
Turbidity in the lubricating oil and deteriorated storage stability
In some cases, it may be inappropriate as a lubricating oil for combustion engines. [Antioxidant] In the present invention, an antioxidant
Nol-based antioxidants are preferably used.
Is represented by the chemical formula (6). Use as engine oil
In order to reduce sublimation at high temperatures,
The molecular weight is preferably 300 or more.(Where m is 1-3). Where R₄₁, R₄₂Is an alkyl group having 1 to 12 carbon atoms;
It is preferably a branched alkyl group having a prime number of 3 to 8. R
₄₃Represents an alkyl group having 4 to 50 carbon atoms, a cycloalkyl group,
Reel group, alkylaryl group, arylalkyl group,
Hydrocarbon groups such as alkenyl groups, ester groups,
-Including ether groups, alcohol groups, carboxyl groups, etc.
May be. Preferably an alkyl group having 6 to 16 carbon atoms is used.
Can be. R₄₁, R₄₂May be the same or different
May be. Also, R₄₁~ R₄₃Antioxidants of different types
These can be mixed and used. The amount of this antioxidant added to the total lubricating oil weight is
0.2 to 5% by weight, preferably 0.5 to 2% by weight.
You. If the amount is less than 0.2% by weight, the antioxidant effect is small.
In addition, even if added in an amount exceeding 5% by weight, the antioxidant effect becomes saturated.
It will add up and the cost will increase. [Other additives] The lubricating oil for an internal combustion engine of the present invention includes:
Further as needed to ensure performance adapted to the application
The lubricating oil additives other than the
Can be improved. Such an engine oil addition
Examples of the agent include alkaline earth metals such as Ca, Mg, Ba, and Na.
Which alkali metal sulfonates, phenates, salici
So-called metal detergents and dispersants such as alkenyl
Succinimide, succinate, succinamide and
Gray dispersants such as
Viscosity index improvers such as rimers and polymethacrylates
Is mentioned. In addition, pour point depressants, rust inhibitors, defoamers, etc.
Any additive or the like may be appropriately added. In addition, ester
Phenols other than phenolic antioxidants having phenolic groups
Antioxidants, amine antioxidants such as diphenylamine
An agent or the like may be appropriately added. (Examples) The present invention will be described in more detail using examples and comparative examples.
I will tell. First, the partially long-chain MoDTC used in the present invention is produced.
You. [2-hexyldecanyl chloride] 2-hexyldecano
240 g (0.99 mol) of chloroform and 900 mL of chloroform
Into a 3L three-necked flask fitted with a cooling tube and a dropping funnel.
120 mL (1.6 mol) of thionyl chloride was added dropwise over 70 minutes.
After stirring at room temperature for 1 hour, 130 mL (0.16 mol) of pyridine was added.
And stirred at room temperature for 1 hour, then at 75 ° C for 5 hours
While stirring. After the reaction, wash with 2 L of water and remove the organic layer.
Dried over sodium hydrogen sulfate. The resulting brown liquid solvent
Was distilled off under reduced pressure, and 150 g of a pale yellow liquid (0.58mo
l) was obtained. The yield was 59%. [Synthesis of secondary amine] 2-hexyldecanyl chloride
5.0 g (0.019 mol) and 2-ethylhexylamine 5.0 g (0.
039 mol) in a 100 mL
The mixture was placed in a Lasco and stirred at 180 ° C. for 11 hours. Due to this reaction
The secondary amine of hydrochloride is formed.
After washing, the residue was kept under reduced pressure to obtain 5.9 g of a pale yellow liquid.
This (2-hexyldecanyl) (2-ethylhexyl)
The yield of the amine was 85%. [Synthesis of MoDTC 1] Na_TwoMoO_Four・ 2H_TwoO 5.1g (0.021mo
l), Na_TwoS ・ 9H_TwoO 5.1 g (0.021 mol) and water 7 mL
Put in a 0 mL one-necked flask and add 20% sulfuric acid aqueous solution to pH 2.5.
And After stirring at room temperature for 30 minutes, (2-hexyldeca
Nyl) (2-ethylhexyl) amine 5.0 g (0.014 mol)
And 1.1 g (0.14 mol) of carbon dioxide, seal, and
At room temperature for 1 hour. Then return to one-neck flask
A diversion cooling tube was attached, and the mixture was stirred at 105 ° C. for 5 hours. reaction
After completion, dissolve in 100 mL of toluene, wash with 300 mL of water,
After the organic layer was dried over anhydrous sodium sulfate, the solvent was distilled off.
And purified using a silica gel column.
6.6 g of a viscous liquid (Synthesis Example 1) was obtained. [Synthesis of MoDTC 2] MoO_Three 24g (0.17mol), Nato hydrosulfide
63 g of an aqueous solution of lium (15-18%) and 200 mL of water are mixed with 500 mL of
The mixture was placed in a flask and adjusted to pH 3.0 with a 20% aqueous sulfuric acid solution.
After stirring at room temperature for 30 minutes, (2-hexyldecanyl) (2
-Ethylhexyl) amine 60g (0.17mol) and carbon disulfide
14 g (0.181 mol) were added. After the reaction, toluene 500
Add mL, seal and wash the organic layer with 1000 mL of water
did. Extract the organic layer and dry over anhydrous sodium sulfate
Thereafter, the solvent was distilled off, and the residue was purified using silica gel.
After washing with butyl alcohol and drying under reduced pressure, brown yellow viscous liquid
[Analysis of MoDTC] Element of MoDTC obtained in Synthesis Example 1
The results of the analysis were Mo 16.8% by weight, S 16.7% by weight, N
It was 2.35% by weight. C₅₀H₁₀₀N_TwoS_FourMo_TwoO_FourTheoretical value as
Is Mo 16.8 wt%, S 16.8 wt%, N 2.45 wt%
It is. Also,¹³From the results of C-NMR analysis, dithiocarba
Single peak (208.7 ppm) due to mate structure confirmed
did it. The result of elemental analysis of MoDTC obtained in Synthesis Example 2 was M
o 17.4% by weight, S 19.4% by weight, N 2.35% by weight
Was. Also,¹³From the results of C-NMR analysis,
A single peak (208.7 ppm) due to the structure of the
Came. By the following steps, MoDTC represented by chemical formula (1)
Oh, R₁And R_ThreeIs a 2-hexyldecyl group, and R_Two
And R_FourIs a 2-ethylhexyl group MoDTC (hereinafter, M
oDTC-1) was produced. Also, similarly, the chemical formula
MoDTC represented by (1), wherein (2-hexyldeca
(2) Instead of (nyl) (2-ethylhexyl) amine, (2
-Hexyldecanyl) (2-ethylhexyl) amine
Di (2-ethylhexyl) amine secondary with equimolar mixing
Amine is used, and MoDTC (hereinafter referred to as the
Below, referred to as MoDTC-2). To these MoDTCs
Ok₁~ Χ₄The ratio of oxygen atoms to sulfur atoms at
It is 1 Using this MoDTC, the engine of Example and Comparative Example
Test oils 1 to 8 were prepared as oils. As the base oil, the following
Mineral oils 1 and 2 having the properties shown in Table 1 were used.

[Table 1] Mineral oil 1 Mineral oil 2 Density (15 ° C) [g / cm ³ ] 0.862 0.821 Kinematic viscosity (40 ° C) [mm ² / s] 17.7 19.7 Kinematic viscosity (100 ° C) [mm ² / s] 3.78 4.51 Viscosity Index [-] 99 147 Pour point [° C] -15.0 -15.0 Saturation content [%] 76.5 98.8 The following additives were used. MoDTC-A: Commercially available MoDTC, in chemical formula (1)
R _{1 to} R ₄ are a 2-ethylhexyl group. MoDTC-B: Commercially available MoDTC, in chemical formula (1)
R _{1 to} R ₄ are an alkyl group having 13 carbon atoms. ZnDTP: a ZnDTP represented by the chemical formula (3), R ₁₁ ~
R ₁₄ is a 2-ethylhexyl group. ZnDTC: a ZnDTC expressed by the chemical formula (4), R ₂₁ ~
R ₂₄ is a 2-ethylhexyl group. The above base oils and additives were mixed at the ratios shown in Tables 2 and 3 to prepare test oils of Examples and Comparative Examples. The mixing ratio is represented by% by weight based on the lubricating oil. In addition,
As a common additive package, metal detergents, ashless dispersants, phenolic antioxidants, amine antioxidants, viscosity index improvers, rust inhibitors and defoamers were added to these test oils. . For the test oils 1 to 8 thus prepared, the friction characteristics in a new oil and a deteriorated oil, a hot tube test,
In addition, storage stability was evaluated. The results are shown in Tables 2 and 3. As the friction characteristics, the friction coefficients of the new oil and the deteriorated oil were measured. The measurement was performed using the SRV tester under the following conditions. Test piece: Ball and disc of diameter 10mm, material SUJ-2 Test condition: Load 100N Amplitude 1.5mm Frequency 50Hz Temperature 80 ℃ Time 20 minutes Here, the new oil is the lubricating oil immediately after mixing, and the deteriorated oil is JI
This lubricating oil has been subjected to an oxidation stability test of a lubricating oil for internal combustion engines in accordance with SK2514. Oxidation stability test was 150
C. for 168 hours. The heat resistance was evaluated by a hot tube test. The deposit amount at a temperature of 310 ° C. was measured using a hot tube tester manufactured by Komatsu Engineering Co., Ltd. The storage stability was determined by storing the test oil in a glass sedimentation tube at 0 ° C. for one month and evaluating whether the test oil caused precipitation. The test oils 1 to 4 of the examples are the test oils 5 of the comparative example.
No precipitation occurs after storage as in Nos. 6 to 6, and the storage stability is excellent. In addition, the test oils 1 to 4 can maintain a low friction coefficient even when used for a long period of time without deterioration of the friction coefficient even when the oil is deteriorated like the test oils 7 to 8 which are comparative examples. Further, the test oils 1 to 4 are less likely to generate deposits due to the hot tube test and are excellent in heat resistance. It can be seen that the test oil 4 containing the sulfur-based additive further reduces the generation of deposits. Further, the above base oils and additives were mixed at the ratios shown in Table 4 to prepare test oils 9 and 10 of Examples and Comparative Examples. The following additives were used as additives in addition to those used in test oils 1 to 8. MoDTC-C: Commercially available MoDTC, in chemical formula (1)
R _{1 to} R ₄ are an alkyl group having 13 or 8 carbon atoms. Thiazoazole compound: a thiadiazole-type polysulfide compound represented by the chemical formula (5),
R ₃₁ and R ₃₂ each represent an alkyl group having 9 carbon atoms;
~ 5. The sulfur content in the additive is 36% by weight. Propionate antioxidant: a phenolic antioxidant having an ester group represented by the chemical formula (6), m is 2, R ₄₁ and R ₄₂ are tertiary butyl groups, and Irganox from Ciba-Geigy An additive sold as L135. The remainder is a common additive package, which is composed of a metal detergent, an ashless dispersant, an amine antioxidant, a viscosity index improver, a rust inhibitor and an antifoaming agent. With respect to the test oils 9 to 10 thus prepared, the friction characteristics in new oil and deteriorated oil, hot tube test,
The storage stability was evaluated in the same manner as in Test Oils 1 to 8. The results are shown in Table 4. However, the deteriorated oil used was deteriorated by a bench durability test in the AMA driving mode under the conditions of oil temperature 100 ° C and water temperature 100 ° C, using a 2L inline 6-cylinder gasoline engine, reducing the oil pan oil amount to 2L. What was used was used. It can be seen that the test oil 9 of the example is less deteriorated in friction coefficient even if it is deteriorated, and can maintain a low friction coefficient even in long-term use, as compared with the test oil 10 of the comparative example. The present invention is a lubricating oil for an internal combustion engine to which a predetermined amount of oxymolybdenum dithiocarbamate having a specific structure is added,
It can maintain a low coefficient of friction even when used for a long time, has excellent heat resistance, and has excellent storage stability and stability. Therefore, it can be used stably for a long period of time in an internal combustion engine using engine oil and the like, and has a remarkable effect on fuel saving.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C10N 40:25 (72) Inventor Koichi Nakamura 3-17-35 Nishinaminami, Toda City, Saitama Prefecture Japan Energy Co., Ltd. (56) References JP-A-6-336592 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C10M 169/04 C10M 135/14-135/18 C10M 137/10 C10M 141/06- 141/10 C10N 40:25 C10N 30:06 C10N 10:12 CA (STN) WPI / L (QUESTEL)

Claims (5)

(57) [Claims] 1. A mineral oil and / or synthetic lubricating oil as a base oil, represented by the following chemical formula (1), wherein R ₁ is an aliphatic hydrocarbon group having 10 or more carbon atoms having a branch at the β-position. Yes, and R ₂ ~
R ₄ is a sulfurized oxymolybdenum dithiocarbamate is the number 4 or more aliphatic hydrocarbon group having a carbon, molybdenum (Mo) amount as 0.005 wt% lubricating oil for internal combustion engines, characterized in that it contains. (In the formula, Χ _{1 to ４ 4} are oxygen atoms or sulfur atoms, which may be the same or different.) 2. The lubricating oil for an internal combustion engine according to claim 1, wherein in the chemical formula (1), R ₁ and R ₃ each have a carbon atom having a branch at the β-position.
A lubricating oil for an internal combustion engine, wherein the lubricating oil is an aliphatic hydrocarbon group having 10 or more, and R ₂ and R ₄ are aliphatic hydrocarbon groups having 4 or more carbon atoms. 3. Zinc dithiophosphate as phosphorus (P) content
The lubricating oil for an internal combustion engine according to claim 1 or 2, which contains 0.01 to 0.2% by weight. 4. The sulfur-based additive as sulfur (S) amount.
The content is 0.01 to 0.5% by weight.
3. The lubricating oil for an internal combustion engine according to any one of 3. 5. The lubricating oil for an internal combustion engine according to claim 1, comprising 0.2 to 5% by weight of a phenolic antioxidant having an ester group.