JPH0647675B2 - Molybdenum dithiocarbamate-containing lubricant composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel molybdenum dithiocarbamate compound useful as a lubricant additive.

In particular, the present invention is an antioxidant property, an antiwear property, a friction relaxation property,
The present invention relates to a compound which is excellent in metal corrosiveness and solubility in a base oil such as mineral oil and which is useful as a molybdenum-containing lubricant additive effective in a wide range of temperatures.

[Conventional technology and problems]

Conventionally, various compositions have been known as lubricating additives for engine oils and the like, but in recent years, the performance required for the lubricating additive has become more and more severe from the viewpoint of resource saving and energy saving. Zinc dithiophosphate (hereinafter referred to as "ZDTP") has been generally used for improving the abrasion resistance, and also, JP-B-40-8426, JP-B-44-27366 or JP-A-56- As disclosed in Japanese Patent Publication No. 110796 and the like, oxymolybdenum dialkylphosphorodithionate sulfide (hereinafter referred to as Mo-DTP) is also used.

However, both ZDTP and Mo-DTP contain a phosphorus atom.

In recent years, purification of automobile exhaust has become obligatory as part of measures to prevent air pollution, and as a technical measure, a method of attaching an exhaust purification catalyst to the exhaust pipe of a gasoline automobile, purifying the exhaust, and complying with regulations is generally performed. ing.

However, some engine oil burns with fuel such as gasoline in the engine, so if the engine oil contains catalyst poison of the exhaust purification catalyst, the catalyst will be poisoned and the performance will deteriorate, so expensive catalyst will be used. Must be exchanged, resource
It becomes a big financial problem.

Phosphorus contained in ZDTP and Mo-DTP has become a problem as a property of poisoning this catalyst, and the concentration used tends to decrease year by year.

Especially, ZDTP is 1 to 2% by weight in order to exert its effect by itself.
Therefore, the phosphorus concentration must be increased accordingly.

Also, since Mo-DTP exerts its effect at a lower concentration than ZDTP, it can be used at a relatively low phosphorus concentration, but the effect is not zero, and
When other additives are blended in order to produce a synergistic effect, if the additives contain phosphorus, the blending amount is restricted due to the problem of the total phosphorus content.

Further, all of the known Mo-DTPs have a low thermal decomposition temperature, and even those having good heat resistance are decomposed almost completely at 250 ° C or lower. Therefore, a lubricating oil used at a high temperature for a long time has a drawback that the active ingredient is drastically reduced.

On the other hand, many molybdenum dithiocarbamate type compounds have been reported (Japanese Patent Publication No. 49-6362 and Japanese Patent Publication No. 51-964).
No. 5, Japanese Patent Publication No. 53-31646, Japanese Patent Publication No. 56-12638, etc.).

However, although these compounds are not problematic in terms of catalyst poisoning, they have drawbacks such as unsatisfactory lubricity and large metal corrosivity, and a common problem is that solubility in base oils such as mineral oil is poor. It has drawbacks. In addition, since its thermal decomposition temperature is high and it decomposes in a narrow temperature range, it has a drawback that its use is limited depending on the compound.

[Means for solving problems]

The present invention provides a novel molybdenum dithiocarbamate having an asymmetrical mixed alkyl group, and by using the same, it is superior in exhaust gas purification catalyst coverage to the conventional ZDTP or molybdenum-containing lubricant additive. toxicity,
It is an object of the present invention to provide a lubricant additive having a wide range of applications, which has antiwear properties, friction mitigation properties, solubility in base oils, and works effectively in a wide temperature range.

The compounds of the present invention have the general formula (Wherein R ₁ and R ₂ are hydrocarbon groups having 4 to 13 carbon atoms, R ₃ and R ₄
Is a hydrocarbon group having 8 to 24 carbon atoms, R ₁ and R ₂ may be the same or different, R ₃ and R ₄ may be the same or different, but R _{1 and} R ₃ are both R ₄ is also different, R ₂ is also R ₃
And R ₄ are different. X is O or S
The four Xs may be the same or different. ) Is a molybdenum dithiocarbamate and is extremely useful as a lubricant additive.

The hydrocarbon group represented by R ₁ and R ₂ in the general formula (1) is n-
Alkyl group such as butyl group, isobutyl group, n-hexyl group, n-octyl group, 2-ethylhexyl group, n-decyl group, dodecyl group, tridecyl group, cyclohexyl group, alicyclic ring such as 2-methylcyclohexyl group Group, benzyl group, aromatic group such as 4-methylbenzyl group, and the hydrocarbon group represented by R ₃ and R ₄ include n-octyl group, 2-ethylhexyl group, n-decyl group and dodecyl group. Groups, alkyl groups such as tridecyl group, hexadecyl group and octadecyl group, alkenyl groups such as hexadecene group and octadecene group, aromatic groups such as octylphenyl group and nonylphenyl group are exemplified as practical ones. . Of these, particularly preferred are R ₁ and R ₂
Are n-octyl group, 2-ethylhexyl group, R ₃ ,
Examples of R ₄ include a dodecyl group and a tridecyl group.

In the general formula (1), the portion represented by X is an oxygen atom or a sulfur atom, and it is necessary that O / S = 1/3 to 3/1. As a method for obtaining the compound of the general formula (1), for example, a part of the present inventor invented, and Japanese Patent Publication Nos. 55-40593 and 56-12638.
The method for producing a molybdenum-containing compound disclosed in JP-A-58-50233 can be used. Specifically, molybdenum trioxide or an alkali metal or ammonium salt of molybdic acid (A) and alkali hydrosulfide or General formula M ₂ S
(In the formula, M is an alkali metal or ammonium group) and an aqueous solution or suspension containing an alkali sulfide (B) represented by a molar ratio of 1: 0.005 to 1: 4 and adjusting the pH to 0.5 to 8. Then, it can be obtained by adding carbon disulfide and a secondary amine and keeping the temperature at 80 ° C. or higher.

Examples of the alkali metal salt of molybdic acid used for producing the compound of the present invention include sodium molybdate, potassium molybdate, and heteropoly acid molybdate.

Examples of the alkali hydrosulfide used in the production of the compound of the present invention or the alkali sulfide (B) represented by the general formula M ₂ S (wherein M is an alkali metal or ammonium group) include sodium sulfide, potassium sulfide, and ammonium sulfide. Etc. are used.

Similarly to these, an aqueous solution obtained by introducing hydrogen sulfide gas into a corresponding aqueous solution of alkali hydroxide is also used.

Alkali metal or ammonium salt of molybdenum trioxide or molybdic acid (A) and alkali hydrosulfide or general formula M ₂
The molar ratio of alkali sulfide represented by S is 1: 0.005.
It is preferably about 1: 4, and it is particularly preferable to use almost equimolar amounts.

The secondary amine used in the compound of the present invention corresponds to R ₁ , R ₂ and R ₃ , R ₄ in the general formula (1), and includes the hydrocarbon groups and the like exemplified as R _{1 to} R _4. Those that have are used. In this case, R ₁ and R ₂ may be the same or different, and R ₃ and R ₄ are the same.

Further, in the case of synthesizing the compound of the present invention, when two kinds of amines are used at the same time, in addition to the product of the present invention, those having the same alkyl group are by-produced, but when used as a lubricant, they are particularly separated. There is no need for it, and the solubilizing power of the product of the present invention results in a composition with good solubility as a whole.

The compounds of the present invention are useful as lubricant additives. The lubricant is usually composed of a base oil or a base, various additives added depending on the application, and the compound of the present invention can be appropriately used in combination with these base oils / bases and additives. .

When the compound of the present invention is used in a lubricant, it is generally preferable that the molybdenum-containing compound is added to the lubricant in an amount of 50 to 1500 ppm, preferably 150 to 1000 ppm, of which the compound of the present invention is 40% by weight or more. It should be added.

Examples of the base oil / base include natural oils such as animal oils, vegetable oils, oils obtained from petroleum, paraffinic oils, naphthenic oils, and mixtures thereof.

Synthetic lubricant oils include olefin polymers and copolymers (eg, polybutylene, polypropylene, propylene-
Isobutylene copolymer, polybutylene chloride, poly (1-hexene) poly (1-octene), poly (1-decene), etc. and mixtures thereof), alkylbenzene (for example, dodecylbenzene, tetradodecylbenzene, dinonylbenzene, di ( 2-ethylhexyl) benzene etc.), polyphenyls (eg biphenyl, terphenyl, alkylpolyphenyl etc.), alkyl diphenyl ethers and diphenyl alkyl sulfides and hydrocarbon oils such as derivatives, analogues and homologs thereof and halogen-substituted carbonization. Includes hydrogen oil. Mention may be made of the oils obtained by the polymerization of ethylene oxide or propylene oxide, the alkyl and aryl ethers of these polyoxyalkylene polymers, as well as their mono- or polycarboxylic acid esters or diesters. Also included are esters of dicarboxylic acids (eg, phthalic acid, succinic acid, alkylsuccinic acids and alkenylsuccinic acids, sebacic acid, adipic acid, linoleic acid dimers, etc.) and various alcohols. Useful esters also include those made from polyhydric alcohol ethers such as neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol. Also, silicic oils such as polyalkyl-, polyaryl-, polyalkoxy- or polyaryloxy-siloxane oils and silicate oils, liquid esters of phosphorus-containing acids (TCP, TOP, diethyl ester of decylphosphonic acid). ) Etc. are included.

Examples of various additives to be added depending on the use include, for example, ash-forming or ashless type auxiliary detergents and dispersants, corrosion and antioxidants, pour point depressants, extreme pressure agents, oiliness agents, colorants and deodorants. Examples include foaming agents.

Ash-producing detergents are carbon and phosphorus obtained by treating alkali metal or alkaline earth metal sulfuric acid, carboxylic acid, or olefin polymer with a phosphorus agent such as phosphorus trioxide, phosphorus pentasulfide, phosphorus trichloride and sulfur. Is represented by a fat-soluble neutral or basic salt such as an organic phosphoric acid having at least one bond directly bonded to. The most commonly used are sodium, potassium, lithium, calcium, magnesium,
It is a salt of strontium and barium.

Examples of the ashless detergent include carboxylic acid-based dispersants, amine dispersants, Mannich dispersants, decyl methacrylate, vinyl decyl ether, and fat-soluble monomers such as high molecular weight olefins and polar such as aminoalkyl acrylates. Examples thereof include a copolymer with a monomer having a certain substituent.

Oiliness agents, extreme pressure agents, corrosion and antioxidants are represented by the following.

1) Chlorinated aliphatic hydrocarbons 2) Benzyl disulfide, bis (chlorobenzyl) disulfide,
Dibutyl tetrasulfide, sulfurized methyl ester of olefinic acid,
Organic sulfides and polysulfides of sulfurized alkylphenols, dipentene sulfides and terpenes 3) Phosphorus hydrocarbons such as reaction products of phosphorus sulfide with turpentine and methyl olefin 4) Dibutyl, diheptyl, dicyclohexyl, pentyl phosphites Phenyl, dipentylphenyl, dioctyl, tridecyl, distearyl, dimethylnaphthyl, diisobutyl-substituted phenyl and other dihydrocarbons and trihydrocarbons Phosphorus ester mainly containing phosphite ester, tricresyl phosphate, trioctyl phosphate, tributyl phosphate, Phosphoric acid esters such as triphenyl phosphate and nonyl phenyl phosphate 5) Zinc dioctylcarbamate, zinc diisoamyldithiocarbamate and barium heptylphenyldithiocarbamate, diisoami Metal salts of thiocarbamic acid such as antimony dithiocarbamate 6) Zinc dicyclohexylphosphorodithioate, zinc dioctylphosphorodithioate, barium di (heptylphenyl) phosphorodithioate, cadmium dinonylphosphorodithioate, and phosphorus pentasulfide and isopropyl alcohol And a group II metal salt of phosphorodithioic acid, such as a zinc salt of phosphorodithioic acid, obtained by reaction with an equimolar mixture of n-hexyl alcohol, di-2-ethylhexyl phosphorodithioic acid oxymolybdenum sulfide, di-n- Butyl phosphorodithionate sulfurized oxymolybdenum salts such as oxymolybdenum sulfide 7) Oily agents such as oleyl alcohol, stearyl alcohol, stearic acid, isostearic acid, oleic acid The application of the lubricant is not particularly limited, and specific applications include spark ignition type and compression ignition type including automobile and truck engines, two-cycle engines, piston engines for aircraft, diesel engines for ships and locomotives, and the like. Internal combustion engine crankcase lubricating oil, gas engine, stationary power engine and turbine lubricating oil, automatic transmission liquid, transaxle lubricant, gear lubricant, metalworking lubricant, hydraulic liquid and other lubricating oil and grease A composition etc. can be illustrated.

〔Example〕

 Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1 300 ml of water, 1.0 mol of sodium molybdate and 1.0 mol of sodium sulfide were placed in a reactor and stirred for 20 minutes.
The pH was adjusted to 2.8 with% sulfuric acid. 0.5 mol of di (2-ethylhexyl) amine, 0.5 mol of di (tridecyl) amine and 1.0 mol of carbon disulfide were added, and the mixture was stirred at room temperature for 30 minutes and then reacted at 95 to 102 ° C for 4 hours. After the reaction is complete, the solid is washed with methanol and dried to yield a green solid.
Obtained at 89.0%. Elemental analysis results are Mo; 16.6%, S; 17.2
%, N; 2.6%. The results of high performance liquid chromatography analysis are shown in FIG.

The high performance liquid chromatographic analysis was performed under the following conditions.

Equipment Shimadzu LC-3A, Column Zorbax-SIL 4.6mm × 25cm,
Solvent benzene / hexane = 1/1 (Vol), flow rate 1.2 ml / min,
Detector Shimadzu SPD-2A, 290nm. Incidentally, in FIG. 1, A
The peaks of R ₁ , R ₂ , R ₃ and R ₄ are all tridecyl groups (hereinafter abbreviated as C ₁₃ -C ₁₃ ), and the peaks of B are R ₁ and R ₂ are 2-ethylhexyl groups, R ₃ and R 4. ₄ is a tridecyl group (hereinafter C ₈
-C ₁₃ ) and C peaks (5 peaks) in which R ₁ , R ₂ , R ₃ and R ₄ are all 2-ethylhexyl groups (hereinafter abbreviated as C ₈ -C ₈ )
Shows the peak of.

As is clear from FIG. 1, the products are C ₈ -C ₁₃ , C ₈ -C ₈ ,
It was a mixture of C ₁₃ -C ₁₃ . The peak area ratio when using a UV detector (290 nm) is C ₈ -C ₁₃ : C ₈ -C ₈ : C ₁₃ -C ₁₃ ≒
It was 50:25:25. The main component of X in general formula (1) was S / O = 2/2.

The product was fractionated and purified using a silica gel column and n-hexane / benzene as a solvent to obtain a liquid purified product having a purity of 90%. Second infrared absorption spectrum of the purified product
Shown in the figure.

Example 2 100 ml of water and 0.3 mol of sodium molybdate were placed in a reactor, and 0.4 mol of 40% sodium hydrosulfide was added with stirring. After adjusting the pH to 3.5 with 20% sulfuric acid,
Add 0.15 mol of di (2-ethylhexyl) amine, 0.15 mol of dilaurylamine, and 0.3 mol of carbon disulfide to obtain 95-
The reaction was carried out at 102 ° C for 8 hours. After completion of the reaction, the solid matter was washed with methanol and dried to obtain a greenish brown solid matter in a yield of 81.8%.
Got with. Elemental analysis results are Mo; 16.1%, S; 17.2%, N; 3.
It was 2%. The peak area ratio by high performance liquid chromatography is
C ₈ -C ₁₂ : C ₈ -C ₈ : C ₁₂ -C ₁₂ ≈ 50:25:25.

Example 3 In the same manner as in Example 1, the reaction was carried out using di (stearin) amine instead of di (tridecyl) amine to obtain a greenish brown solid in a yield of 93.7%. Elemental analysis results are Mo; 1
The percentages were 3.2%, S; 15.0%, N; 2.2%. Peak area ratio by high performance liquid chromatography is C ₈ -C ₁₈ : C ₈ -C ₈ : C ₁₈ -C ₁₈ ≈ 48:27:
Was 25.

Comparative Example 1 In the same manner as in Example 1, the reaction was carried out by using di (2-ethylhexyl) amine alone to obtain a yellowish brown solid substance in a yield of 86.7%.
Got with. Elemental analysis results are Mo; 19.9%, S; 20.3%, N; 3.
It was 1%.

Comparative Example 2 In the same manner as in Example 1, di (tridecyl) amine was used alone to carry out the reaction to obtain a yellowish brown solid substance in a yield of 88.6%. Elemental analysis results are Mo; 16.3%, S; 16.8%, N; 2.2%
Met.

Example 4 The compounds obtained in Examples 1, 2 and 3 and Comparative Examples 1 and 2 were added to special spindle oil at 1% or diisodecyl adipate (D
IDA) 10%, dissolved at 70 ℃, left at room temperature for 1 week,
The presence or absence of precipitation was checked.

The evaluation criteria are as follows.

◯: Both precipitation and turbidity could not be visually confirmed.

Δ: No precipitation was visually confirmed, but turbidity was confirmed.

X: Precipitation was visually confirmed.

The results are shown in Table 1.

Example 5 The decomposition start temperature and the decomposition end temperature were measured by the differential thermal analysis of the compounds obtained in Examples 1, 2, 3 and Comparative Examples 1, 2.

The results are shown in Table 2.

Example 6 The compounds obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were used as 150
A molybdenum content of 0.04% by weight was dissolved in neutral oil, and wear resistance was measured by a shell four-ball tester (oil temperature 2
3 at 5 ℃, 120 ℃, load 40kg, 1800rpm
(Indicated by the diameter of the wear mark after 0 minutes).

The results are shown in Table 3.

Example Inventive Product A The same as the above except that 0.5 mol of di (2-ethylhexyl) amine and 0.5 mol of di (tridecyl) amine were replaced by 0.5 mol of n-docosyl-n-dodecylamine and 0.5 mol of n-dibutylamine. A reaction product was obtained in the same manner as in Example 1.

The yield is 88%, the Mo content is 16.3% (theoretical value 18.1%),
The S content was 16.8% (theoretical value 18.1%).

The O / S corresponding to X in the general formula (1) was 2.5 / 1.5.

Comparative product B According to the method of Reference Example 2 of JP-A-51-80825, MoS ₃
The compound was synthesized. According to the elemental analysis ratio of Mo and S, the composition is
It was MoS _3.1 .

Next, MoS _3.1 0.5 moles of dimethylformamide 500ml
Was placed in a four-necked flask having an inner volume of 2 equipped with a stirrer, a thermometer, and a reflux condenser.

Carbon disulfide 1 in a mixture of 0.5 mol of n-docosyl-n-dodecylamine and 0.5 mol of n-dibutylamine at room temperature
The mixture obtained by adding mols dropwise is added to the flask and the temperature
The reaction was carried out at 90 to 100 ° C for 5 hours. After cooling, the obtained reaction mixture was filtered, washed with methanol, and dried to obtain a reaction product.

The yield is 82%, the Mo content is 16.8% (theoretical value 17.5%),
The S content was 23.8% (theoretical value 23.5%).

The O / S corresponding to X in the general formula (1) was 0/4.

Comparative test The metal corrosiveness of the invention product A and the comparative product B was evaluated.
That is, a copper plate corrosion test was conducted according to JIS K-2513 on a composition obtained by dissolving 1 part by weight of each of the present invention product A and comparative product B in 99 parts by weight of dioctyl phthalate and dissolving them. still,
The test time is 3 hours and the temperature is 100 ° C.

As a result, the composition of the invention product A was 1b, whereas the composition of the comparative product B was 4a, and it is clear that the comparative product B is highly corrosive and lacks practicality. .

[Brief description of drawings]

FIG. 1 is a chart of high performance liquid chromatographic analysis of the product of Example 1, and FIG. 2 is a chart of infrared absorption spectrum of the purified product of Example 1.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C10N 30:06 30:10 30:12 40:25 8217-4H (72) Inventor Noriyoshi Tanaka Tokyo Asahi Denka Kogyo Co., Ltd. 7-35, Higashi-Ohaku, Arakawa-ku (72) Inventor Masanori Konishi 7-5-235 Higashi-Ohgu, Arakawa-ku, Tokyo Asahi Denka Kogyo Co., Ltd. 7-35 Higashiohisa, Arakawa-ku, Tokyo Inside Asahi Denka Co., Ltd.

Claims (2)

[Claims] 1. A general formula, (Wherein R ₁ and R ₂ are hydrocarbon groups having 4 to 13 carbon atoms, R ₃ and R ₄
Is a hydrocarbon group having 8 to 24 carbon atoms, R ₁ and R ₂ may be the same or different, R ₃ and R ₄ may be the same or different, but R _{1 and} R ₃ are both R ₄ is also different, R ₂ is also R ₃
And R ₄ are different. X is O or S
4 X's may be the same or different, but O / S = 1
/ 3 to 3/1. ) A lubricant composition containing molybdenum dithiocarbamate represented by 2. A lubricant composition containing molybdenum dithiocarbamate according to claim ₁ , wherein R ₁ and R ₂ are octyl groups and R ₃ and R ₄ are dodecyl groups or tridecyl groups.