CA1333799C - Stabilised diesel engine oil - Google Patents
Stabilised diesel engine oilInfo
- Publication number
- CA1333799C CA1333799C CA 570728 CA570728A CA1333799C CA 1333799 C CA1333799 C CA 1333799C CA 570728 CA570728 CA 570728 CA 570728 A CA570728 A CA 570728A CA 1333799 C CA1333799 C CA 1333799C
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Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B3/00—Engines characterised by air compression and subsequent fuel addition
- F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition
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Abstract
A lubricant oil composition comprising a diesel engine oil and, as antioxidant, a compound of formula I
I
wherein R1 and R2 are each independently of the other C1-C12alkyl and X is ,
I
wherein R1 and R2 are each independently of the other C1-C12alkyl and X is ,
Description
~ 333799 3-16536/+
Stabilised diesel engine oil The present invention relates to a diesel engine oil which is stabilised with an ester of a sterically hindered 3-~4-hydroxy-phenyl) compound and to the use of said ester of 3-(3-hydroxy-phenyl~ compound for stabilising diesel engine oils.
Owing to the substantially greater load as compared with Otto engines and to the sulfur content of the diesel fuel, resistance to wear, oxidation and corrosion stability, low residue formation and nonsludging capacity are especially important for lubricant oils for diesel engines.
The life of diesel engines depends substantially on piston cleanliness as well as on the wear of the cylinder bore and on the wear of piston rings and bearings caused by mechanical abrasion and chemical corrosion. Abrasion is increased by engine soiling.
Corrosive wear is mainly caused by the sulfur content of the fuel, which results in the formation of highly corrosive sulfur-containing acids. The higher thermal stresses in the piston area necessitate the use of detergent additives for effectively preventing increased coking and lacquering on the piston under these conditions. As diesel engines discharge more solid combustion products into the engine oil than do gasoline engines, dispersant additives are added to the lubricating oil to prevent sludge formation. In addition, the trend towards longer oil-change intervals requires an adequate stability to ageing of the lubricating oils for diesel engines.
These oils must not thicken appreciably over the entire running time and must prevent the formation of residues. Good thermal and oxidative stability is therefore essential.
Ash-free antioxidants of the alkylated diphenylamine or sterically hindered phenol type are not markedly effective in lubricant oils for diesel engines.
Esters of 3-( 3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid are disclosed as antioxidants for polymers, industrial oils and for diesel fuel in US patent specifications 3 285 855, 3 330 859, 3 345 327 and 4 652 272.
Surprisingly, it has now been found that esters of a sterically hindered 3-(4-hydroxyphenyl) compound are very effective anti-oxidants for diesel engine lubricating oils.
The present invention relates to a lubricant oil composition comprising a diesel engine oil and, as antioxidant, a compound of formula I
Rl~
HC) ~ X
wherein Rl and R2 are each independently of the other C1-C12alkyl and X is -CH2-CH2-C-OR, -CH~-S-CH~-~-OR or -CH2-S-R and R is a straight chain or branched alkyl radical of the formula -C H2 +1' wherein n is an integer from 9 to 30.
Rl and R2 as C1-C12alkyl are straight chain or branched, preferably branched, alkyl radicals and, most preferably, those in which the (Y-carbon atom is a tertiary carbon atom, for example methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, straight chain or branched pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl or dodecyl.
_ 3 _ 1 333799 The C H2 +1 radical denotes preferably straight chain Cg-C30alkyl radicals. Most preferably the C H2 +1 radical denotes a straight chain C1s-C30alkyl radical.
R as Cg-C30alkyl is for example nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, eicosyl, heneicosyl, docosyl and others up to triacontyl. Preferred are C1s-C30alkyl radicals as defined above.
A preferred lubricant oil composition is one in which the diesel engine oil is an engine oil of API classes CC, CD or class CD~ ).
The API classes CC and CD are classifications of the American Petroleum Institute for engine oils. The C classes relate to diesel engine oils which, in accordance with their degree of doping and thus performance rating, are given a further letter in their classification.
Engine oils of the CC class conform to the requirements for diesel aspirating engines since 1961. They contain additives for the prevention of high- and low-temperature deposits and of corrosion (requirement according to MIL-L-2104 B).
Class CD engine oils conform to the requirements of supercharged diesel engines, also those powered by fuels of higher sulfur content. They contain additives for the prevention of high-temperature deposits, wear and corrosion.
The CD( ) class comprises engine oils for higher supercharged vehicle diesel engines which do not yet have an API classification.
These oils are required above all in Europe, where engine oils are subjected to very high thermal stress on account of the high performance/weight ratio of the diesel engines.
The basis oil used for the preparation of engine oils of the aforementioned classes is normally a mineral oil. However, it can also consist of hydrogenated mineral oil distillates such as severely hydrotreated oil (refining hydrogenation, Ullmann's Encyclopedia of Industrial Chemistry, Vol. 10, pp. 6gO-699, Verlag Chemie, Weinheim, 1977) or hydrocracked oil (cleaving hydrogenation, Ullmann's Encyclopedia of Industrial Chemistry, Vol. 10, pp. 690-706, Verlag Chemie, Weinheim 1977) or synthetic components or mixtures thereof.
The synthetic oils comprise e.g. oils based on diesters, complex esters or poly-~-olefins.
A further preferred lubricant oil composition is one in which the diesel engine oil is a lubricant oil based on mineral oil, a synthetic oil or a mixture thereof, of SAE viscosity classes 15 W 40 or 30, and comprising 2.5 to 7.5 % by weight of a detergent, 3.5 to 6.0 % by weight of a dispersant and 1.2 to 1.8 % by weight of a zinc dialkyldithiophosphate.
Yet a further preferred lubricant oil composition is one in which the diesel engine oil contains 0.5 to 2.0 % by weight, preferably 0.75 to 1.5 % by weight, of an antiwear additive in addition to the detergent, dispersant and zinc dialkyldithiophosphate.
Examples of detergents which are added to diesel engine oils are basic alkali metal sulfonates or alkaline earth metal sulfonates such as sodium, calcium and magnesium salts of long-chain alkylarylsulfonic acids or basic alkali metal or alkaline earth metal phenolates and salicylates.
The dispersants for diesel engine oils are for example polyiso-butenylsuccinimides, polybutenylphosphonic acid derivatives or copolymers of vinyl acetate and fumaric acid esters.
The zinc dialkyldithiophosphates are preferably compounds of the general formula RO-P-S Zn R'O
wherein R and R' are each independently of the other C2-CI2alkyl preferably C2-Cgalkyl, and the total number of carbon atoms of R and R' is at least 5.
The antiwear additives are for example polar, oil-soluble substances such as fatty alcohols, fatty acids, fatty acid esters or fatty acid amides whose acti~ity increases with increasing molecular weight and in the sequence alcohol ~ ester < unsaturated acid < saturated acid.
A useful lubricant oil composition is also one comprising a diesel engine oil, an antioxidant of formula I and also, as additional antioxidant, a triarylphosphite, a trialkylphosphite, a mixed alkylarylphosphite andtor a thio compound of formula II
(ÇH2) -~-oR3 II
(CH2) ~ -oR3 wherein R3 is C6-C24alkyl, preferably Clz-Clgalkyl, and m is an integer from 1 to 6.
Examples of triarylphosphites, trialkylphosphites and mixed alkyl-arylphosphites are triphenylphosphite, diphenylalkylphosphites, phenyldialkylphosphites, tris(nonylphenyl)phosphite, trilauryl-phosphite, trioctyldecylphosphite, distearylpentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl)phosphite, diisodecyl-pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl)penta-erythritol diphosphite, tristearyl sorbitol triphosphite.
Examples of compounds of formula II are dilaurylthiodipropionate and distearylthiopropionate.
A particularly preferred lubricant oil composition is one which contains a compound of formula I, wherein Rl and R2 are each independently of the other Cl-C4alkyl.
A further especially preferred lubricant oil composition is one which contains a compound of formula I, wherein Rl and R2 are identical and are a tert-butyl radical.
Likewise very preferred is a lubricant oil composition which contains a compound of formula I, wherein Rl is methyl and R2 is tert-butyl.
A further interesting lubricant oil composition is one which contains a compound of formula I, wherein n is an integer from 12 to 24 and is preferably 1~.
A particularly interesting lubricant oil composition is one in which the compound of formula I is n-octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.
Examples of compounds of formula I are:
n-nonyl-3-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionate, 2-butyl-octyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, n-eicosyl-3-(3,5-diisopropyl-4-hydroxyphenyl)propionate, 2-hexyldecyl-3-(5-tert-octyl-4-hydroxy-3-methylphenyl)propionate, 7 21~89-7425 n-triacontyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, n-octadecyl-3-(3~5-di-Lert-butyl-4-llydroxyphenyl)propionate~
n-dodecyl-3-(3,5-di-n-dodecyl-4-hydroxyphenyljpropionate.
The compounds ot tormu1a I are known and can be prepared in a mallner known per se, for example by the methods described in US patent specifications 3 247 240, 4 085 13~ and 4 228 297. Any compounds which are novel can be prepared in analogous manner.
Preferred compositions of the present invention contain a compound ol lormu1a \ / CH~-S-CH2-~-0-C i~2 +1 (Ia) X
wherein n is an integer from 9 to 30, preterably trom 12 to 24 and, most preferab1y, is 18.
A1so preterred are compositlons containillg a compound ot tormula H0--~ ~--CH~-S-C H2 +1 (Ib) . _ --wherein n is an integer from 9 to 30, preferably from 12 to 24 and, mu~L pre1er~b1y, 1~
The compounds of formula I are excellent antioxidants for diesel engine oils. They are added thereto preferably in an amount of 0.2 to 2.0 % by weight, most preferably 0.5 to 1.5 % by weight, based on the total weight of the lubricant oil composition.
Hence the present invention also relates to the use of compounds of formula I for stabilising diesel engine oil against oxidative degradation.
The diesel engine oils stabilised with the compounds of formula I
may preferably be used in the following types of diesel engines:
- high-speed vehicle diesel engines which are naturally aspirated or supercharged (automobiles, locomotives), - marine diesel engines such as 4-cycle trunk-type piston engines, or 2-cycle crosshead diesel engines, - gas diesel engines.
The lubricant oil compositions of this invention can contain still further additives which are added to the diesel engine oil to improve its basic properties further, for example viscosity modifiers.
Examples of viscosity modifiers are polymethacrylates, vinylpyrrolidone/methacrylate copolymers, polybutenes, olefin copolymers or styrene/acrylate copolymers.
In the following Examples parts and percentages are by weight, unless otherwise stated.
1 33379~
g Example 1: Engine test in a MWM test diesel engine in accordance with DIN 51 361 or CECL 12-A-76 The field of application of this test relates to engine oils. The purpose of the test is to assess the cleansing action of engine oils. This is done by testing principally the snug fit of the piston rings and the coke-like deposits in the piston ring grooves of diesel engines.
Piston cleanliness in the context of this standard denotes the ability of engine lubricating oils to keep the engine clean internally and to keep in check the unavoidable impurities stemming from combustion [extraneous oil contamination and by ageing substances which form in the engine lubricating oil (inherent oil contamination)].
a) Test procedure and test engine:
A new test piston is run in with the engine lubricating oil for testing in the test engine. There follows a 50 hour test run with a fresh oil supply under exactly defined and constantly maintained operating conditions of the test engine.
The test engine is a single cylinder four-cycle diesel engine, type MWM KD 12E. This engine is a rotochamber aspirating engine with an engine capacity of 0.85 1 (cylinder bore 95 mm, piston stroke 120 mm) and a highest useful compression ratio of 22.
Operating conditions of the engine during the test run Test duration: 50 hours without interruption.
Gradual increase of engine speed and torque from start of operation so that the following engine speed and useful performance is reached after ca. 30 minutes:
- lo - 1 333799 engine speed: 2200 min 1 + 25 min 1 fuel consumption: 3100 g/h + 40 g/h coolant inlet temperature: at least 100C
coolant outlet temperature: (110 + 2)C.
Amount of oil: 3.2 1; the weight must be determined and entered in the test report. The engine lubricating oil must not be replenished or drawn off during the test run.
Lubricating oil consumption: at most 1400 g for the 50 hour duration of the test run.
oil temperature in the crankcase: (110+ 2)C
oil pressure: 1.3 to 1.8 bar overpressure exhaust gas counterpressure: 25 to 45 mbar air suction temperature: 25 to 35C
density of exhaust smoke: density value according to Bosch:
at most 4.
After the 50 hour test run, the piston cleanliness is evaluated by visual observation in accordance with DIN 51 361, Part 2.
The values corresponding to a specific piston cleanliness are reported in Table 1 Table 1 Piston cleanliness Evaluation factor clean 100 discoloured 65 black 30 coke - 30 The 1st, 2nd and 3rd groove beds, the 2nd piston land, the piston head and piston skirt are evaluated.
1 33~799 At each site the product of the respective piston cleanliness and the area thereof is formed.
A mean value is computed for the measuring sites at the 1st, 2nd and 3rd groove bed and at the 1st and 2nd land of the piston.
b) Test procedure The base oil is a formulated mineral oil of SAE viscosity class 15 ~-40 with a TBN (total basic number) of 8.8 mg of KOH/g of mineral oil and having a Zn content of 0.11 % by weight, a P content of 0.095 % by weight, a Ca content of 0.25 % by weight, a Mg content of 0.045 % by weight and a sulfate ash content of 1.21 ~O by weight.
This corresponds to a zinc dialkyldithiophosphate content of 1.2 %
by weight, a detergent content (magnesium sulfonate, calcium phenate) content of 3.5 % by weight and a dispersant content of 3.5 % by weight.
The oil additionally contains 8 % by weight of a viscosity modifier (olefin copolymer). The oil is thus a diesel engine oil of API
class CD.
The antioxidant of formula I of this invention is added to this base oil and the measurement is made as described in a).
The results are reported in Table 2.
- 1~ - 1 3 3 3 7 9 9 Table 2 ~easuring Base Base oil Base oil site oil + 0.6 % of AO + 1.2 % of AO
1st groove bed 18 40 27 2nd groove bed 84 93 8~
3rd groove bed 100 100 100 1st land 62 63 67 Znd land 100 98 98 Mean value 73 79 7~
AO = n-octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate Example 2: Following the procedure described in Example 1, the improvement in the cleansing action of a base oil of the following composition is tested hy the addition of an antioxidant of formula I of this invention to said base oil.
Base oil: formulated mineral oil of SAE viscosity class l0 W-30 with a TBN (total basic number) of 5.5 mg of ~OH/g of mineral oil and having a Zn content ol 0 07 C~O by weight, a P content of 0.07 ~/O by weight, a calcium content of 0.2 % by weight and a sulfate ash content of 0.74 % by weight. This corresponds to a zinc dialkyldithiophosphate content of O.Y ~/O by weight, a detergent content (calci~m sulfonate, calcium phenate) of 3.0 % by weight, and a dispersant content of 3.5 % by weight.
The oil additionally contains 6 ~O by weight of a viscosity modifier ~olefin copolymer). The oil is thus a diesel engine oil of API
class CC.
The antioxidant is n-octadecyl-3-(3,5-di-tert-butyl-4-hydroxy-phenyl)propionate.
The results are reported in Table 3 Table 3 Measuring site Base oil Base oil + 0.6 ~/0 of AO
1st groove bed O O
2nd groove bed 22 71 3rd groove bed ~1 98 1st land 44 53 2nd land 86 93 Mean value 49 63
Stabilised diesel engine oil The present invention relates to a diesel engine oil which is stabilised with an ester of a sterically hindered 3-~4-hydroxy-phenyl) compound and to the use of said ester of 3-(3-hydroxy-phenyl~ compound for stabilising diesel engine oils.
Owing to the substantially greater load as compared with Otto engines and to the sulfur content of the diesel fuel, resistance to wear, oxidation and corrosion stability, low residue formation and nonsludging capacity are especially important for lubricant oils for diesel engines.
The life of diesel engines depends substantially on piston cleanliness as well as on the wear of the cylinder bore and on the wear of piston rings and bearings caused by mechanical abrasion and chemical corrosion. Abrasion is increased by engine soiling.
Corrosive wear is mainly caused by the sulfur content of the fuel, which results in the formation of highly corrosive sulfur-containing acids. The higher thermal stresses in the piston area necessitate the use of detergent additives for effectively preventing increased coking and lacquering on the piston under these conditions. As diesel engines discharge more solid combustion products into the engine oil than do gasoline engines, dispersant additives are added to the lubricating oil to prevent sludge formation. In addition, the trend towards longer oil-change intervals requires an adequate stability to ageing of the lubricating oils for diesel engines.
These oils must not thicken appreciably over the entire running time and must prevent the formation of residues. Good thermal and oxidative stability is therefore essential.
Ash-free antioxidants of the alkylated diphenylamine or sterically hindered phenol type are not markedly effective in lubricant oils for diesel engines.
Esters of 3-( 3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid are disclosed as antioxidants for polymers, industrial oils and for diesel fuel in US patent specifications 3 285 855, 3 330 859, 3 345 327 and 4 652 272.
Surprisingly, it has now been found that esters of a sterically hindered 3-(4-hydroxyphenyl) compound are very effective anti-oxidants for diesel engine lubricating oils.
The present invention relates to a lubricant oil composition comprising a diesel engine oil and, as antioxidant, a compound of formula I
Rl~
HC) ~ X
wherein Rl and R2 are each independently of the other C1-C12alkyl and X is -CH2-CH2-C-OR, -CH~-S-CH~-~-OR or -CH2-S-R and R is a straight chain or branched alkyl radical of the formula -C H2 +1' wherein n is an integer from 9 to 30.
Rl and R2 as C1-C12alkyl are straight chain or branched, preferably branched, alkyl radicals and, most preferably, those in which the (Y-carbon atom is a tertiary carbon atom, for example methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, straight chain or branched pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl or dodecyl.
_ 3 _ 1 333799 The C H2 +1 radical denotes preferably straight chain Cg-C30alkyl radicals. Most preferably the C H2 +1 radical denotes a straight chain C1s-C30alkyl radical.
R as Cg-C30alkyl is for example nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, eicosyl, heneicosyl, docosyl and others up to triacontyl. Preferred are C1s-C30alkyl radicals as defined above.
A preferred lubricant oil composition is one in which the diesel engine oil is an engine oil of API classes CC, CD or class CD~ ).
The API classes CC and CD are classifications of the American Petroleum Institute for engine oils. The C classes relate to diesel engine oils which, in accordance with their degree of doping and thus performance rating, are given a further letter in their classification.
Engine oils of the CC class conform to the requirements for diesel aspirating engines since 1961. They contain additives for the prevention of high- and low-temperature deposits and of corrosion (requirement according to MIL-L-2104 B).
Class CD engine oils conform to the requirements of supercharged diesel engines, also those powered by fuels of higher sulfur content. They contain additives for the prevention of high-temperature deposits, wear and corrosion.
The CD( ) class comprises engine oils for higher supercharged vehicle diesel engines which do not yet have an API classification.
These oils are required above all in Europe, where engine oils are subjected to very high thermal stress on account of the high performance/weight ratio of the diesel engines.
The basis oil used for the preparation of engine oils of the aforementioned classes is normally a mineral oil. However, it can also consist of hydrogenated mineral oil distillates such as severely hydrotreated oil (refining hydrogenation, Ullmann's Encyclopedia of Industrial Chemistry, Vol. 10, pp. 6gO-699, Verlag Chemie, Weinheim, 1977) or hydrocracked oil (cleaving hydrogenation, Ullmann's Encyclopedia of Industrial Chemistry, Vol. 10, pp. 690-706, Verlag Chemie, Weinheim 1977) or synthetic components or mixtures thereof.
The synthetic oils comprise e.g. oils based on diesters, complex esters or poly-~-olefins.
A further preferred lubricant oil composition is one in which the diesel engine oil is a lubricant oil based on mineral oil, a synthetic oil or a mixture thereof, of SAE viscosity classes 15 W 40 or 30, and comprising 2.5 to 7.5 % by weight of a detergent, 3.5 to 6.0 % by weight of a dispersant and 1.2 to 1.8 % by weight of a zinc dialkyldithiophosphate.
Yet a further preferred lubricant oil composition is one in which the diesel engine oil contains 0.5 to 2.0 % by weight, preferably 0.75 to 1.5 % by weight, of an antiwear additive in addition to the detergent, dispersant and zinc dialkyldithiophosphate.
Examples of detergents which are added to diesel engine oils are basic alkali metal sulfonates or alkaline earth metal sulfonates such as sodium, calcium and magnesium salts of long-chain alkylarylsulfonic acids or basic alkali metal or alkaline earth metal phenolates and salicylates.
The dispersants for diesel engine oils are for example polyiso-butenylsuccinimides, polybutenylphosphonic acid derivatives or copolymers of vinyl acetate and fumaric acid esters.
The zinc dialkyldithiophosphates are preferably compounds of the general formula RO-P-S Zn R'O
wherein R and R' are each independently of the other C2-CI2alkyl preferably C2-Cgalkyl, and the total number of carbon atoms of R and R' is at least 5.
The antiwear additives are for example polar, oil-soluble substances such as fatty alcohols, fatty acids, fatty acid esters or fatty acid amides whose acti~ity increases with increasing molecular weight and in the sequence alcohol ~ ester < unsaturated acid < saturated acid.
A useful lubricant oil composition is also one comprising a diesel engine oil, an antioxidant of formula I and also, as additional antioxidant, a triarylphosphite, a trialkylphosphite, a mixed alkylarylphosphite andtor a thio compound of formula II
(ÇH2) -~-oR3 II
(CH2) ~ -oR3 wherein R3 is C6-C24alkyl, preferably Clz-Clgalkyl, and m is an integer from 1 to 6.
Examples of triarylphosphites, trialkylphosphites and mixed alkyl-arylphosphites are triphenylphosphite, diphenylalkylphosphites, phenyldialkylphosphites, tris(nonylphenyl)phosphite, trilauryl-phosphite, trioctyldecylphosphite, distearylpentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl)phosphite, diisodecyl-pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl)penta-erythritol diphosphite, tristearyl sorbitol triphosphite.
Examples of compounds of formula II are dilaurylthiodipropionate and distearylthiopropionate.
A particularly preferred lubricant oil composition is one which contains a compound of formula I, wherein Rl and R2 are each independently of the other Cl-C4alkyl.
A further especially preferred lubricant oil composition is one which contains a compound of formula I, wherein Rl and R2 are identical and are a tert-butyl radical.
Likewise very preferred is a lubricant oil composition which contains a compound of formula I, wherein Rl is methyl and R2 is tert-butyl.
A further interesting lubricant oil composition is one which contains a compound of formula I, wherein n is an integer from 12 to 24 and is preferably 1~.
A particularly interesting lubricant oil composition is one in which the compound of formula I is n-octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.
Examples of compounds of formula I are:
n-nonyl-3-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionate, 2-butyl-octyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, n-eicosyl-3-(3,5-diisopropyl-4-hydroxyphenyl)propionate, 2-hexyldecyl-3-(5-tert-octyl-4-hydroxy-3-methylphenyl)propionate, 7 21~89-7425 n-triacontyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, n-octadecyl-3-(3~5-di-Lert-butyl-4-llydroxyphenyl)propionate~
n-dodecyl-3-(3,5-di-n-dodecyl-4-hydroxyphenyljpropionate.
The compounds ot tormu1a I are known and can be prepared in a mallner known per se, for example by the methods described in US patent specifications 3 247 240, 4 085 13~ and 4 228 297. Any compounds which are novel can be prepared in analogous manner.
Preferred compositions of the present invention contain a compound ol lormu1a \ / CH~-S-CH2-~-0-C i~2 +1 (Ia) X
wherein n is an integer from 9 to 30, preterably trom 12 to 24 and, most preferab1y, is 18.
A1so preterred are compositlons containillg a compound ot tormula H0--~ ~--CH~-S-C H2 +1 (Ib) . _ --wherein n is an integer from 9 to 30, preferably from 12 to 24 and, mu~L pre1er~b1y, 1~
The compounds of formula I are excellent antioxidants for diesel engine oils. They are added thereto preferably in an amount of 0.2 to 2.0 % by weight, most preferably 0.5 to 1.5 % by weight, based on the total weight of the lubricant oil composition.
Hence the present invention also relates to the use of compounds of formula I for stabilising diesel engine oil against oxidative degradation.
The diesel engine oils stabilised with the compounds of formula I
may preferably be used in the following types of diesel engines:
- high-speed vehicle diesel engines which are naturally aspirated or supercharged (automobiles, locomotives), - marine diesel engines such as 4-cycle trunk-type piston engines, or 2-cycle crosshead diesel engines, - gas diesel engines.
The lubricant oil compositions of this invention can contain still further additives which are added to the diesel engine oil to improve its basic properties further, for example viscosity modifiers.
Examples of viscosity modifiers are polymethacrylates, vinylpyrrolidone/methacrylate copolymers, polybutenes, olefin copolymers or styrene/acrylate copolymers.
In the following Examples parts and percentages are by weight, unless otherwise stated.
1 33379~
g Example 1: Engine test in a MWM test diesel engine in accordance with DIN 51 361 or CECL 12-A-76 The field of application of this test relates to engine oils. The purpose of the test is to assess the cleansing action of engine oils. This is done by testing principally the snug fit of the piston rings and the coke-like deposits in the piston ring grooves of diesel engines.
Piston cleanliness in the context of this standard denotes the ability of engine lubricating oils to keep the engine clean internally and to keep in check the unavoidable impurities stemming from combustion [extraneous oil contamination and by ageing substances which form in the engine lubricating oil (inherent oil contamination)].
a) Test procedure and test engine:
A new test piston is run in with the engine lubricating oil for testing in the test engine. There follows a 50 hour test run with a fresh oil supply under exactly defined and constantly maintained operating conditions of the test engine.
The test engine is a single cylinder four-cycle diesel engine, type MWM KD 12E. This engine is a rotochamber aspirating engine with an engine capacity of 0.85 1 (cylinder bore 95 mm, piston stroke 120 mm) and a highest useful compression ratio of 22.
Operating conditions of the engine during the test run Test duration: 50 hours without interruption.
Gradual increase of engine speed and torque from start of operation so that the following engine speed and useful performance is reached after ca. 30 minutes:
- lo - 1 333799 engine speed: 2200 min 1 + 25 min 1 fuel consumption: 3100 g/h + 40 g/h coolant inlet temperature: at least 100C
coolant outlet temperature: (110 + 2)C.
Amount of oil: 3.2 1; the weight must be determined and entered in the test report. The engine lubricating oil must not be replenished or drawn off during the test run.
Lubricating oil consumption: at most 1400 g for the 50 hour duration of the test run.
oil temperature in the crankcase: (110+ 2)C
oil pressure: 1.3 to 1.8 bar overpressure exhaust gas counterpressure: 25 to 45 mbar air suction temperature: 25 to 35C
density of exhaust smoke: density value according to Bosch:
at most 4.
After the 50 hour test run, the piston cleanliness is evaluated by visual observation in accordance with DIN 51 361, Part 2.
The values corresponding to a specific piston cleanliness are reported in Table 1 Table 1 Piston cleanliness Evaluation factor clean 100 discoloured 65 black 30 coke - 30 The 1st, 2nd and 3rd groove beds, the 2nd piston land, the piston head and piston skirt are evaluated.
1 33~799 At each site the product of the respective piston cleanliness and the area thereof is formed.
A mean value is computed for the measuring sites at the 1st, 2nd and 3rd groove bed and at the 1st and 2nd land of the piston.
b) Test procedure The base oil is a formulated mineral oil of SAE viscosity class 15 ~-40 with a TBN (total basic number) of 8.8 mg of KOH/g of mineral oil and having a Zn content of 0.11 % by weight, a P content of 0.095 % by weight, a Ca content of 0.25 % by weight, a Mg content of 0.045 % by weight and a sulfate ash content of 1.21 ~O by weight.
This corresponds to a zinc dialkyldithiophosphate content of 1.2 %
by weight, a detergent content (magnesium sulfonate, calcium phenate) content of 3.5 % by weight and a dispersant content of 3.5 % by weight.
The oil additionally contains 8 % by weight of a viscosity modifier (olefin copolymer). The oil is thus a diesel engine oil of API
class CD.
The antioxidant of formula I of this invention is added to this base oil and the measurement is made as described in a).
The results are reported in Table 2.
- 1~ - 1 3 3 3 7 9 9 Table 2 ~easuring Base Base oil Base oil site oil + 0.6 % of AO + 1.2 % of AO
1st groove bed 18 40 27 2nd groove bed 84 93 8~
3rd groove bed 100 100 100 1st land 62 63 67 Znd land 100 98 98 Mean value 73 79 7~
AO = n-octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate Example 2: Following the procedure described in Example 1, the improvement in the cleansing action of a base oil of the following composition is tested hy the addition of an antioxidant of formula I of this invention to said base oil.
Base oil: formulated mineral oil of SAE viscosity class l0 W-30 with a TBN (total basic number) of 5.5 mg of ~OH/g of mineral oil and having a Zn content ol 0 07 C~O by weight, a P content of 0.07 ~/O by weight, a calcium content of 0.2 % by weight and a sulfate ash content of 0.74 % by weight. This corresponds to a zinc dialkyldithiophosphate content of O.Y ~/O by weight, a detergent content (calci~m sulfonate, calcium phenate) of 3.0 % by weight, and a dispersant content of 3.5 % by weight.
The oil additionally contains 6 ~O by weight of a viscosity modifier ~olefin copolymer). The oil is thus a diesel engine oil of API
class CC.
The antioxidant is n-octadecyl-3-(3,5-di-tert-butyl-4-hydroxy-phenyl)propionate.
The results are reported in Table 3 Table 3 Measuring site Base oil Base oil + 0.6 ~/0 of AO
1st groove bed O O
2nd groove bed 22 71 3rd groove bed ~1 98 1st land 44 53 2nd land 86 93 Mean value 49 63
Claims (16)
1. A lubricant oil composition comprising a diesel engine oil and, as antioxidant, a compound of formula I
I
wherein R1 and R2 are each independently of the other C1-C12alkyl and X is or -CH2-S-R and R is a straight chain or branched alkyl radical of the formula -CnH2n+1, wherein n is an integer from 9 to 30.
I
wherein R1 and R2 are each independently of the other C1-C12alkyl and X is or -CH2-S-R and R is a straight chain or branched alkyl radical of the formula -CnH2n+1, wherein n is an integer from 9 to 30.
2. A lubricant oil composition according to claim 1, wherein the diesel engine oil is an engine oil of API classes CC, CD
or class CD(+).
or class CD(+).
3. A lubricant oil composition according to either claim 1 or claim 2, wherein the diesel engine oil is a lubricant oil based on mineral oil, a synthetic oil or a mixture thereof, of SAE viscosity classes 15 W 40 or 30, which contains 2.5 to 7.5 % by weight of a detergent, 3.5 to 6.0 % by weight of a dispersant and 1.2 to 1.8 %
by weight of a zinc dialkyldithiophosphate.
by weight of a zinc dialkyldithiophosphate.
4. A lubricant oil composition according to claim 3, wherein the diesel engine oil additionally contains 0.5 to 2.0 % by weight of an antiwear agent.
5. A lubricant oil composition according to claim 1 which contains, as additional antioxidant, a triarylphosphite, a trialkylphosphite, a mixed alkylarylphosphite and/or a thio compound of formula II
II
wherein R3 is C6-C24alkyl and m is an integer from 1 to 6.
II
wherein R3 is C6-C24alkyl and m is an integer from 1 to 6.
6. A lubricant oil composition according to claim 1 which contains a compound of formula I, wherein R1 and R2 are each independently of the other C1-C4alkyl.
7. A lubricant oil composition according to claim 5 which contains a compound of formula I, wherein R1 and R2 are identical and are a tert-butyl radical.
8. A lubricant oil composition according to claim 5 which contains a compound of formula I, wherein R1 is methyl and R2 is tert-butyl.
9. A lubricant oil composition according to claim 1 which contains a compound of formula I, wherein X is and n is an integer from 9 to 30.
10. A lubricant oil composition according to claim 1 which contains a compound of formula I, wherein X is and n is an integer from 9 to 30.
11. A lubricant oil composition according to claim 1 which contains a compound of formula I, wherein X is -CH2-S-CnH2n+1 and n is an integer from 9 to 30.
12. A lubricant oil composition according to any one of claims 9, 10 or 11 which contains a compound of formula I, wherein n is an integer from 12 to 24.
13. A lubricant oil composition according to claim 12 which contains a compound of formula I, wherein n is 18.
14. A lubricant oil composition according to claim 1, wherein the compound of formula I is n-octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.
15. A lubricant oil composition according to claim 1 which contains a compound of formula I in an amount of 0.2 to 2.0 % by weight, based on said lubricant oil composition.
16. A method of stabilising diesel engine oil against oxidative degradation, which comprises the use of a compound of formula I
according to claim 1.
according to claim 1.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH2479/87-9 | 1987-07-01 | ||
| CH247987 | 1987-07-01 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1333799C true CA1333799C (en) | 1995-01-03 |
Family
ID=4234725
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 570728 Expired - Fee Related CA1333799C (en) | 1987-07-01 | 1988-06-29 | Stabilised diesel engine oil |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1333799C (en) |
-
1988
- 1988-06-29 CA CA 570728 patent/CA1333799C/en not_active Expired - Fee Related
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