JP2941557B2 - Lubricating oil additives consisting of sulfurized monoalkyl catechol and its derivatives - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating oil additive comprising an oil-soluble sulfurized monoalkyl catechol and a derivative thereof, and more particularly to an oil-soluble sulfurized monoalkyl catechol and a derivative thereof having excellent antioxidant and antiwear properties. The present invention relates to a lubricating oil additive, particularly a lubricating oil additive for an internal combustion engine, and a method for producing the same.

[0002]

2. Description of the Related Art Recently, internal combustion engines have achieved remarkable fuel saving and high output. This requires lubricating oils to have excellent friction reducing properties, oxidation stability at high temperatures, and cleanliness.

The ability of monoalkyl catechols to function as lubricating oil antioxidants, friction reducers and diesel engine deposit inhibitors has been disclosed in US Pat.
43,838. U.S. Pat. No. 4,729,848 states that metal dithiophosphates of monoalkyl catechols are useful as antiwear agents in lubricating oils for gasoline and diesel engines. However, monoalkyl catechol has a problem in antioxidant properties at high temperatures. Further, since the metal dithiophosphate of monoalkyl catechol is a compound containing phosphorus which has a poisoning effect on the exhaust gas purifying catalyst, its use is restricted due to stricter exhaust gas regulations in the future.

In US Pat. No. 4,221,673, it is possible to produce a lubricating oil additive having excellent rust inhibitory properties by adding 10 to 50% by weight of an alkyldihydroxybenzene in producing a sulfurized or non-sulfurized phenate. Is stated. However, in this patent, as the amount of added nonyl catechol increases, the viscosity of the overbased sulfurized phenate increases, and nonyl catechol becomes 100%
In this case, it is described that solidification is caused by addition of calcium hydroxide. In the production of non-sulfurized phenate, it is a physical mixture of alkylphenol and alkyldihydroxybenzene, and in the production of sulfurized phenate, it is a compound in which alkylphenol and alkyldihydroxybenzene are bonded by a sulfur bridge. That is, the patent does not consider using alkyl catechol or sulfided alkyl catechol as an additive as it is.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a lubricating oil additive having excellent antioxidant and antiwear properties at high temperatures and a method for producing the same.

[0006]

The inventors of the present invention have studied the performance of monoalkyl catechols and found that the monoalkyl catechols and their alkaline earth metal salts and borates are excellent at high temperatures. Have been found to have antioxidant and antiwear properties, and have completed the present invention.

That is, the lubricating oil additive of the present invention is characterized by comprising at least one selected from monoalkyl catechol sulfide, alkaline earth metal salt of monoalkyl catechol sulfide, and sulfurized monoalkyl catechol borate. .

The sulfurized monoalkyl catechol used as a lubricating oil additive in the present invention is usually obtained by sulfurizing an alkylated catechol. The alkylated catechol is usually obtained by reacting catechol with an olefin in the presence of a catalyst. As the olefin used herein, those having 12 to 30 carbon atoms are preferably used, and specifically, for example, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene Α-olefins such as, 1-octadecene, 1-nonadecene, 1-eicosene, 1-heneicosene, 1-docosene; oligomers of olefins having 3 to 5 carbon atoms such as propylene tetramer, propylene pentamer, butene trimer and butene tetramer; Alternatively, a mixture of two or more of these may be used. The catalyst used may be a conventional alkylation catalyst, for example, an acidic catalyst such as iron chloride or an ion exchange resin. The reaction temperature is usually 50 to 200 ° C, preferably 100 to 150.
° C.

[0009] Sulfurized monoalkyl catechol is usually obtained by reacting the above alkyl catechol with elemental sulfur or sulfur chloride. The amount of elemental sulfur or sulfur chloride at this time is arbitrary, but the reaction is carried out so that the amount of sulfur in the produced sulfurized monoalkyl catechol becomes 0.05 to 15% by weight, preferably 1.0 to 10% by weight. It is desirable. When using elemental sulfur, the reaction temperature is usually 100 to 250 ° C, preferably 150 to 200 ° C. The reaction time is usually 2 to 6 hours. When sulfur chloride is used, the reaction temperature is usually 0 to 30C, preferably 10 to 20C. The reaction time is usually 4 to 8 hours.

The alkaline earth metal salt of a sulfurized monoalkyl catechol of the present invention is obtained by reacting a sulfurized monoalkyl catechol with an alkaline earth metal hydroxide or oxide. Specific examples of the alkaline earth metal hydroxide or oxide include magnesium hydroxide, calcium hydroxide, barium hydroxide, magnesium oxide,
Examples thereof include calcium oxide and barium oxide.

At this time, it is preferable to add an alkanol having 1 to 4 carbon atoms in an amount of 5 to 30% by weight based on the monoalkyl catechol sulfide, since the reaction can be carried out quickly. As the alkanol having 1 to 4 carbon atoms, a monoalkanol or a dialkanol is preferably used. Specifically, methanol, ethanol, propanol, butanol, ethylene glycol, propylene glycol, triethylene glycol, butylene glycol, tetramethylene glycol and These mixtures can be exemplified.

At this time, the diluting solvent may be present in an amount of 50 to 200% by weight based on the monoalkyl catechol sulfide, and a non-polar organic solvent having a boiling point of 60 ° C. or higher can be used. Specifically, aromatic hydrocarbons such as benzene, toluene and xylene, petroleum solvents such as benzene, ligroin, mineral spirits and cleaning solvents, and gasoline fractions of mineral oils, kerosene fractions, gas oil fractions, lubricating oil fractions, etc. Can be exemplified.

The reaction conditions are optional, but
The reaction is preferably performed at a temperature of 130 ° C., preferably 130 to 160 ° C., for 2 to 8 hours, preferably 3 to 5 hours.

As a preferred method, it is also possible to simultaneously carry out the sulfidation of the monoalkyl catechol and the salification of the alkaline earth metal by coexisting an alkaline earth metal hydroxide or oxide during the sulfurization reaction of the monoalkyl catechol. . Of course, at this time, the alkanol having 1 to 4 carbon atoms or a diluting solvent may be present. Also in this case, the reaction conditions are optional, but at 100 to 200 ° C., preferably 130 to 150 ° C. for 2 to 8 hours, preferably 3 to 5 hours.
It is preferable to react for a time.

In any of the above cases, the addition amount of the alkaline earth metal hydroxide or oxide is important, and the addition amount of the alkaline earth metal hydroxide or oxide is preferably 1.0 to 1 mol of the monoalkyl catechol sulfide. If the amount exceeds mol, the product is solidified, so the amount is preferably 0.1 to 1.0 mol, preferably 0.2 to 0.5 mol. In the case where an alkaline earth metal hydroxide or oxide is simultaneously present during the sulfurization reaction of the monoalkyl catechol, the amount of the alkaline earth metal hydroxide or oxide, the alkanol having 1 to 4 carbon atoms, and the amount of the diluting solvent may be reduced. Is calculated as sulfide monoalkyl catechol or once obtained.

Thereafter, if necessary, the alkanol, the diluting solvent or both components may be distilled off.

The borated ester of sulfurized monoalkylcatechol of the present invention can be obtained by reacting sulfurized monoalkylcatechol with boric acid. Specific examples of boric acid include orthoboric acid, metaboric acid,
Examples thereof include boric acid and boric anhydride. Generally, orthoboric acid is preferred. The reaction conditions are arbitrary, but usually 1
The reaction is carried out at 50 to 200 ° C., preferably 170 to 190 ° C. while distilling out water, and the end of the reaction can be judged by the elimination of water distillation. The amount of boric acid is arbitrary, but as a boron content in the formed sulfurized monoalkyl catechol borate, 0.05 to 2.0 mol, preferably 0.1 to 2.0 mol, per mol of the sulfurized monoalkyl catechol.
Desirably, it is 1.0 mole.

As described above, the sulfurized monoalkyl catechol and its derivative alkaline earth metal salt and borate ester in the present invention can be obtained. However, if necessary, unreacted raw materials and by-products are removed. Therefore, it may be further purified by means such as filtration.

Since the monoalkyl catechol, its alkaline earth metal salt and borate ester in the present invention all have excellent antioxidant and antiwear properties, they may be used as such or diluted with an appropriate solvent. Thus, it can be used as an additive for lubricating oil. That is, a lubricating oil composition can be obtained by adding the above-mentioned sulfided monoalkyl catechol, its alkaline earth metal salt and borate ester to a lubricating base oil.

The base oil is not particularly limited, and may be any oil that is usually used as a base oil for lubricating oil. As a mineral oil, for example, a lubricating oil fraction obtained by atmospheric distillation and vacuum distillation of crude oil is subjected to solvent removal, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrorefining, and sulfuric acid washing. Oils such as paraffinic and naphthenic oils which are appropriately combined with a refining treatment such as a clay treatment can be used. Examples of synthetic oils include polybutene, 1
Poly-α-olefins such as octene oligomers and 1-decene oligomers; alkylbenzenes; alkylnaphthalenes; diesters such as ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, and di-2-ethylhexyl sebacate; trimethylol Polyol esters such as propane caprylate, trimethylolpropane pelargonate, pentaerythritol 2-ethylhexanoate, and pentaerythritol pelargonate; polyoxyalkylene glycol; polyphenyl ether; perfluoroalkyl ether can be used. These base oils may be used alone or in combination of two or more.

When the lubricating base oil of the present invention contains a monoalkyl catechol, an alkaline earth metal salt thereof, and a borate ester in a lubricating base oil, the contents thereof are each 0 based on the total amount of the composition. .01
It is desirably from 10 to 10% by weight, preferably from 0.1 to 5% by weight.

The lubricating oil composition of the present invention can be used as gasoline engine oil, diesel engine oil, hydraulic oil, gear oil, automatic transmission oil and the like. Also, depending on the application and required performance, metal detergents, ashless dispersants, extreme pressure agents, friction reducers, rust inhibitors, corrosion inhibitors, defoamers, pour point depressants, viscosity index improvers, antioxidants Ordinary lubricating oil additives such as agents may be used in combination.

[0023]

EXAMPLES Hereinafter, the contents of the present invention will be described more specifically with reference to examples and the like, but the present invention is not limited thereto.

Synthesis Example 1 (Production of alkyl catechol) 550 g (5 mol) of catechol and 1580 g of Amberlyst as an alkylation catalyst were each placed in a 3 liter round bottom four-necked flask. The flask was heated to 120 ° C. to melt the contents. 1,232 g of a mixture of 1-tetradecene, 1-hexadecene and 1-octadecene at 40% by weight: 40% by weight: 20% by weight, respectively
(5.5 mol) was taken in a dropping bottle and dropped into the flask over 3 hours in a nitrogen stream. Thereafter, the reaction was performed for 2 hours while maintaining the temperature at 120 ° C. After completion of the reaction, the catalyst was removed by filtration. The filtrate was transferred to a three-necked flask, and unreacted catechol and hexadecene were removed by vacuum distillation.
Thereafter, a fraction at 1 mmHg and 225 to 235 ° C. was used as a product. ^{By 13} C-NMR, the product was 55% 3-alkylcatechol and 40% 4-alkylcatechol.
And 5% of dialkylcatechol.

Embedded image (Wherein R is 1-tetradecene, 1-hexadecene, 1
A branched alkyl group derived from an octadecene mixture. )

Synthesis Example 2 (Production 1 of Sulfurized Monoalkyl Catechol) 167 g of the alkyl catechol obtained in Synthesis Example 1 (0.
5 mol), 12.8 g (0.4 mol) of elemental sulfur
The mixture was taken in a four-necked flask with a capacity of m1 and reacted at 195 ° C. for 4 hours. After the reaction, the reaction product was filtered with a 0.45 μm Millipore filter using Celite as an auxiliary. The obtained sulfurized monoalkyl catechol had the following structural formula containing 2.73% of sulfur (calculated value: 2.74%).

Embedded image (Wherein R and R ′ are each independently a branched alkyl group derived from a mixture of 1-tetradecene, 1-hexadecene and 1-octadecene, and the bonding site to the benzene ring is 3 or 4 Rank.)

Synthesis Example 3 (Production of Sulfurized Monoalkylcatechol 2) 167 g of the alkyl catechol obtained in Synthesis Example 1 (0.
5 mol), 5.15 g (0.5 mol) of sulfur dichloride in 50
The mixture was placed in a 0 ml four-necked flask and dropped at 20 ° C. for 4 hours to react. After the completion of the dropwise addition, the reaction was further performed for 1 hour. After the reaction, the reaction product was filtered with a 0.45 μm Millipore filter using Celite as an auxiliary. The obtained sulfurized monoalkyl catechol has a sulfur content of 8.8% (calculated value 8.
9%).

Embedded image (Wherein R and R ′ are each independently a branched alkyl group derived from a mixture of 1-tetradecene, 1-hexadecene and 1-octadecene, and the bonding site to the benzene ring is 3 or 4 Rank.)

Example 1 (Production 1 of calcium salt of monoalkyl catechol sulfide) Monoalkyl catechol 90 sulfide synthesized in Synthesis Example 2
g, calcium hydroxide 9 g, ethylene glycol 25
g, 90 g of diluent oil (100 neutral oil) to 500 m
The mixture was placed in a 1-liter four-necked flask and reacted at 120 ° C. for 4 hours. Thereafter, ethylene glycol was removed by distillation at 195 ° C. for 1 hour. Filtration under reduced pressure was performed using celite as a filter aid to obtain a calcium salt of sulfurized monoalkylcatechol. The Ca content of the calcium salt of the sulfurized monoalkylcatechol is 2.7% (calculated value 2.7%), and the base number (JIS)
K2501) was 74.6.

Example 2 (Production of Calcium Salt of Sulfurized Monoalkylcatechol 2) Sulfurized monoalkylcatechol 90 synthesized in Synthesis Example 3
g, calcium hydroxide 9 g, ethylene glycol 25
g, 90 g of diluent oil (100 neutral oil) to 500 m
The mixture was placed in a 1-liter four-necked flask and reacted at 120 ° C. for 4 hours. Thereafter, ethylene glycol was removed by distillation at 195 ° C. for 1 hour. Filtration under reduced pressure was performed using celite as a filter aid to obtain a calcium salt of sulfurized monoalkylcatechol. The Ca content of the calcium salt of the sulfurized monoalkylcatechol is 2.6% (calculated value 2.7%), and the base number (JIS)
K2501) was 64.9.

Example 3 (Production of Calcium Salt of Sulfurized Monoalkylcatechol 3) Monoalkylcatechol 65.6 synthesized in Synthesis Example 1
g, 7.4 g of calcium hydroxide, 6.4 g of elemental sulfur, 16 g of ethylene glycol, and 76 g of diluent oil (100 neutral oil) in a 300 ml four-necked flask.
The reaction was performed at 5 ° C. for 4 hours. Thereafter, ethylene glycol was removed by distillation at 195 ° C. for 1 hour. Filtration under reduced pressure was performed using celite as a filter aid to obtain a calcium salt of sulfurized monoalkylcatechol. The Ca content of the calcium salt of the sulfurized monoalkylcatechol is 2.4% (calculated value: 2.7).
%) And the base number (JIS K2501) were 74.1.

Example 4 (Production of borate ester of sulfurized monoalkyl catechol) Sulfurized monoalkyl catechol 65 synthesized in Synthesis Example 3
g and 12 g of orthoboric acid were placed in a 200 ml four-necked flask and reacted at 180 in a nitrogen stream for 8 hours. The obtained boric ester of sulfurized monoalkylcatechol contained 3.9% of boron (calculated value: 4.8%).

Examples 5 to 8 and Comparative Examples 1 to 4 The lubricating oil compositions containing the sulfurized monoalkylcatechol, its calcium salt and its borate obtained in Synthesis Examples 2 to 3 and Examples 2 and 4 were prepared. Abrasion resistance was evaluated by a high-speed four-ball test. Table 1 shows the results. Further, in the table, as comparative examples, data of lubricating oil compositions containing only base oil, monoalkyl catechol (Synthesis Example 1), commercially available calcium sulfurized alkylphenate and sulfurized alkylphenol are also shown. The base oil is a hydrogenated mineral oil of SAE10, and the content of various additives (compounds) is 2% by weight.

[0032]

[Table 1]

The antioxidant properties of these lubricating oil compositions were evaluated by a thin film oxidation test at 150 ° C. (ASTM D4742). Table 2 shows the results.

[0034]

[Table 2]

[0035]

As described above, it is possible to mix a sulfurized monoalkyl catechol and its derivatives, a sulfurized monoalkyl catechol alkaline earth metal salt and a borate ester, with a lubricating base oil as a lubricating oil additive. Thus, a lubricating oil composition excellent in both abrasion resistance at high temperatures and antioxidant properties can be obtained.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C10N 30:10 40:25 70:00

Claims (5)

(57) [Claims] 1. A monoalkyl catechol sulfide and 0.1 to 1.0 mol per mol of the monoalkyl catechol sulfide.
A method for producing a lubricating oil additive comprising a sulfurized monoalkyl catechol alkaline earth metal salt, characterized by reacting with a molar alkaline earth metal hydroxide or oxide. 2. A monoalkyl catechol, elemental sulfur or sulfur chloride, and 0.1 to 1.0 mol per mol of the monoalkyl catechol, which is calculated once assuming that the monoalkyl catechol has been obtained. A method for producing a lubricating oil additive comprising a sulfurized monoalkyl catechol alkaline earth metal salt, characterized by reacting the alkaline earth metal hydroxide or oxide of the above. 3. A method for producing a lubricating oil additive comprising a sulfurized monoalkyl catechol borate, which comprises reacting a sulfurized monoalkyl catechol with boric acid. 4. A lubricating oil additive comprising at least one member selected from the group consisting of a sulfurized monoalkyl catechol, a sulfurized monoalkyl catechol alkaline earth metal salt, and a sulfurized monoalkyl catechol borate. 5. A lubricating oil composition comprising a lubricating base oil containing the lubricating oil additive according to claim 4 as an essential component.