Lubricating oil composition for corrosion control

Abstract

A lubricating oil composition is disclosed. The composition includes a major amount of an oil of lubricating viscosity, one or more alkylhydroxybenzoic acid compounds derived from isomerized normal alpha olefins, and an antioxidant system including a molybdenum-containing antioxidant and diphenylamine. The molybdenum-containing antioxidant is present in an amount that provides at least 120 ppm of Mo to the lubricating oil composition. The diphenylamine is present in an amount that provides 0.5 wt% or more of diphenylamine to the lubricating oil composition.

Description

Technical Field

[0001] Inventors: Peter KLEIJWEGT; Kevin ZEVENBERGEN The present disclosure relates to lubricating oil compositions. More specifically, the present disclosure relates to lubricating oil formulations designed to improve corrosion control.

Background Art

[0002] Antioxidants are widely used as additives that give one or more performance advantages to lubricating oils. These advantages include extension of drain intervals, maintenance of viscosity, reduction of deposits, reduction of foam formation, protection from corrosion, and / or protection from high temperatures. One potential problem with lubricating oil formulations is that antioxidants do not always fully compatible with other components. For example, the combination of antioxidant(s) and alkylhydroxybenzoic acid (“salicylate”) detergent(s) can have an adverse effect on the corrosion resistance of the lubricating oil.

Summary of the Invention

[0003] In one aspect, there is provided a lubricating oil composition comprising a major amount of an oil of lubricating viscosity, one or more alkylhydroxybenzoic acid compounds derived from isomerized normal alpha olefins, and an antioxidant system comprising a molybdenum-containing antioxidant and diphenylamine, the molybdenum-containing antioxidant being present in an amount that provides at least 120 ppm of Mo to the lubricating oil composition, and the diphenylamine being present in an amount that provides 0.5 wt% or more to the lubricating oil composition.

[0004] In another aspect, a method for reducing copper corrosion in an engine is provided, the method comprising lubricating the engine with a lubricating oil composition comprising a major amount of oil of lubricating viscosity, one or more alkylhydroxybenzoic acid compounds derived from isomerized normal alpha olefins, and an oxidation inhibitor system comprising a molybdenum-containing antioxidant and a diphenylamine, wherein the molybdenum-containing antioxidant is present in an amount providing the lubricating oil composition with at least 120 ppm Mo and the diphenylamine is present in an amount providing the lubricating oil composition with at least 0.5 wt % Mo.

[0005] In yet another aspect, there is provided a lubricating oil composition comprising a major amount of oil of lubricating viscosity, one or more alkylhydroxybenzoic acid compounds derived from C10 to C40 isomerized normal alpha olefins, and an oxidation inhibitor system comprising a molybdenum-containing antioxidant and a diphenylamine, wherein the molybdenum-containing antioxidant is present in an amount providing the lubricating oil composition with at least 120 ppm Mo, and the diphenylamine is present in an amount providing the lubricating oil composition with at least 0.5 wt % Mo. DETAILED DESCRIPTION OF THE INVENTION

[0006] Where combinations, subsets, groups, etc. of elements are disclosed (e.g., combinations of components in a composition or combinations of steps in a method), it is understood that although specific reference to each of the various individual and collective combinations and permutations of those elements may not be expressly disclosed, each is specifically contemplated and described herein.

[0007] The present disclosure relates to lubricating oil compositions formulated to enhance or improve corrosion resistance. The lubricating oil compositions of the present disclosure include an alkylhydroxybenzoic acid detergent and an oxidation inhibitor system consisting of at least two different antioxidants.

[0008] More specifically, it has been unexpectedly discovered that alkylhydroxybenzoic acids or alkyl groups thereof that contain or are derived from isomerized normal alpha olefins, when formulated in combination with an antioxidant, provide improved resistance to corrosion.

[0009] In some embodiments, the lubricating oil compositions of this disclosure comprise: (a) a major amount of oil of lubricating viscosity; (b) one or more alkylhydroxybenzoic acids or alkyl groups thereof comprising or derived from C10 to C40 isomerized normal alpha olefins; and (c) an oxidation inhibitor system comprising: (i) a molybdenum compound present in an amount providing 120 ppm or greater Mo; and (ii) diphenylamine present in an amount of 0.5 wt. % or greater, based on the lubricating oil composition.

[0010] Alkyl hydroxybenzoate detergent The lubricating oil compositions of this disclosure comprise one or more alkylhydroxybenzoic acid detergents comprising or derived from C10 to C40 isomerized normal alpha olefins (NAO). In some embodiments, the alkyl group of the alkylhydroxybenzoic acid comprises or is derived from isomerized NAO. In some embodiments, production of the alkylhydroxybenzoic acid comprises alkylating phenol or another aromatic precursor with isomerized NAO.

[0011] Detergents used in engine oils are typically anionic materials containing a long-chain hydrophobic portion of the molecule and a smaller, anionic or lipophilic hydrophilic portion of the molecule. The long-chain hydrophobic portion of the alkylhydroxybenzoic acid detergents of the present disclosure is an isomerized NAO. The anionic portion of the alkylhydroxybenzoic acid detergent is derived from a carboxylic acid. The counterion is typically an alkaline earth metal or alkali metal.

[0012] The alkylhydroxybenzoic acid detergents of the present disclosure can be represented by the following generalized structure: [ka] In the formula, R” is a C10-C40 alkyl group (i.e., having 10 to 40 carbon atoms), n is an integer from 1 to 4, and M is an alkaline earth metal (e.g., Ca or Mg).

[0013] In some embodiments, the C10-C40 alkyl group is an isomerized normal alpha olefin (NAO) having an isomerization level (i) of about 0.10 to about 0.40, such as 0.10 to 0.35, 0.10 to 0.30, 0.10 to 0.25, 0.10 to 0.20, 0.10 to 0.15, 0.15 to 0.35, 0.15 to 0.30, 0.15 to 0.25, 0.15 to 0.20, 0.20 to 0.40, 0.20 to 0.35, 0.20 to 0.30, 0.20 to 0.25, 0.25 to 0.40, 0.25 to 0.35, 0.25 to 0.30, 0.30 to 0.40, 0.30 to 0.35, or 0.35 to 0.40.

[0014] In some embodiments, the isomerization level is about 0.12 to about 0.30, about 0.12 to about 0.25, about 0.12 to about 0.23, about 0.12 to about 0.22, about 0.12 to about 0.20, about 0.13 to about 0.19, about 0.14 to about 0.18, or about 0.15 to about 0.17.

[0015] The isomerization level (i) of the olefin is 1 determinable by 1H-NMR. More specifically, the isomerization level (i) represents the relative amount of methyl groups (-CH3) (chemical shift 0.3 to 1.01 ppm) bonded to methylene backbone groups (-CH2-) (chemical shift 1.01 to 1.38 ppm). The formula for the isomerization level (i) is as follows: Isomerization level = m / (m + n) where m is the NMR integration value of methyl groups with a chemical shift of 0.3 ± 0.03 to 1.01 ± 0.03 ppm, and n is the NMR integration value of methylene groups with a chemical shift of 1.01 ± 0.03 to 1.38 ± 0.1 ppm.

[0016] Useful alkylhydroxybenzoic acid detergents are neutral, moderately overbased, or highly overbased. In some embodiments, the lubricating oil composition can include alkylhydroxybenzoic acid detergents having various levels of TBN. A salt containing a stoichiometric amount of metal is called a neutral salt. Many detergents are overbased and contain a large amount of metal base achieved by reacting an acidic gas (e.g., carbon dioxide) rich in an excess amount of a metal compound (e.g., metal hydroxide or oxide). Overbased detergents neutralize acidic impurities generated by the combustion process and assist in becoming trapped in the oil. The degree of overbasing generally depends on the equivalent ratio of metal ions to the anionic portion of the detergent.

[0017] The alkylhydroxybenzoic acid detergents of the present disclosure have a TBN of 10 mg KOH / g or more, such as 15 mg KOH / g or more, 25 mg KOH / g or more, 50 mg KOH / g or more, 75 mg KOH / g or more, 100 mg KOH / g or more, 125 mg KOH / g or more, 150 mg KOH / g or more, 175 mg KOH / g or more, 200 mg KOH / g or more, 225 mg KOH / g or more, 250 mg KOH / g or more, 275 mg KOH / g or more, 300 mg KOH / g or more, 325 mg KOH / g or more, 350 mg KOH / g or more, 375 mg KOH / g or more, 400 mg KOH / g or more, 425 mg KOH / g or more, 450 mg KOH / g or more, 475 mg KOH / g or more, 500 mg KOH / g or more, 525 mg KOH / g or more, 550 mg KOH / g or more, 575 mg KOH / g or more, 600 mg KOH / g or more, and 650 mg KOH / g or more on an oil-free basis as measured by ASTM D-2896.

[0018] In some embodiments, the alkyl hydroxybenzoate detergent of the present disclosure has an oil-free basis of 10 to 650 mg KOH / g as measured by ASTM D-2896, for example, 10 to 600 mg KOH / g, 10 to 550 mg KOH / g, 10 to 500 mg KOH / g, 10 to 450 mg KOH / g, 10 to 400 mg KOH / g, 10 to 350 mg KOH / g, 10 to 300 mg KOH / g, 10 to 250 mg KOH / g, 10 to 200 mg KOH / g, 10 to 150 mg KOH / g, 10 to 100 mg KOH / g, 10 to 50 mg KOH / g, 50 to 650 mg KOH / g, 50 to 600 mg KOH / g, 50 to 550 mg KOH / g, 50 to 500 mg KOH / g, 50 to 450 mg KOH / g, 50 to 400 mg KOH / g, 50 to 350 mg KOH / g, 50 to 300 mg KOH / g, 50 to 250 mg KOH / g, 50 to 200 mg KOH / g, 50 to 150 mg KOH / g, 50 to 100 mg KOH / g, 100 to 650 mg KOH / g, 100 to 600 mg KOH / g, 100 to 550 mg KOH / g, 100 to 500 mg KOH / g, 100 to 450 mg KOH / g, 100 to 400 mg KOH / g, 100 to 350 mg KOH / g, 100 to 300 mg KOH / g, 100 to 250 mg KOH / g, 100 to 200 mg KOH / g, 100 to 150 mg KOH / g, 150 to 650 mg KOH / g, 150 to 600 mg KOH / g, 150 to 550 mg KOH / g, 150 to 500 mg KOH / g, 150 to 450 mg KOH / g, 150 to 400 mg KOH / g, 150 to 350 mg KOH / g, 150 to 300 mg KOH / g, 150 to 250 mg KOH / g, 150 to 200 mg KOH / g, 200 to 650 mg KOH / g, 200 to 600 mg KOH / g, 200 to 550 mg KOH / g, 200 to 500 mg KOH / g, 200 to 450 mg KOH / g, 200 to 400 mg KOH / g, 200 to 350 mg KOH / g, 200 to 300 mg KOH / g, 200 to 250 mg KOH / g, 250 to 650 mg KOH / g, 250 to 600 mg KOH / g, 250 to 550 mg KOH / g, 250 to 500 mg KOH / g, 250 to 450 mgIt has a TBN of 250 - 400 mg KOH / g, 250 - 350 mg KOH / g, 250 - 300 mg KOH / g, 300 - 650 mg KOH / g, 300 - 600 mg KOH / g, 300 - 550 mg KOH / g, 300 - 500 mg KOH / g, 300 - 450 mg KOH / g, 300 - 400 mg KOH / g, 300 - 350 mg KOH / g, 350 - 650 mg KOH / g, 350 - 600 mg KOH / g, 350 - 550 mg KOH / g, 350 - 500 mg KOH / g, 350 - 450 mg KOH / g, 350 - 400 mg KOH / g, 400 - 650 mg KOH / g, 400 - 600 mg KOH / g, 400 - 550 mg KOH / g, 400 - 500 mg KOH / g, 400 - 450 mg KOH / g, 450 - 650 mg KOH / g, 450 - 600 mg KOH / g, 450 - 550 mg KOH / g, 450 - 500 mg KOH / g, 500 - 650 mg KOH / g, 500 - 600 mg KOH / g, 500 - 550 mg KOH / g, 550 - 650 mg KOH / g, 550 - 600 mg KOH / g, or 600 - 650 mg KOH / g.

[0019] In some embodiments, the alkylhydroxybenzoic acid detergents of the present disclosure have an oil-free content of 10 to 150 mg KOH / g, e.g., 10 to 140 mg KOH / g, 10 to 130 mg KOH / g, 10 to 120 mg KOH / g, 10 to 110 mg KOH / g, 10 to 100 mg KOH / g, 10 to 90 mg KOH / g, 10 to 80 mg KOH / g, 10 to 70 mg KOH / g, 10 to 60 mg KOH / g, 10 to 50 mg KOH / g, 10 to 40 mg KOH / g, 10 to 30 mg KOH / g, 10 to 20 mg KOH / g, 20 to 150 mg KOH / g, 20 to 140 mg KOH / g, 20 to 130 mg KOH / g, 20 to 120 mg KOH / g, 20 to 110 mg KOH / g, 20~100mg KOH / g, 20~90mg KOH / g, 20~80mg KOH / g, 20~70mg KOH / g, 20~60mg KOH / g, 20~50mg KOH / g, 20~40mg KOH / g, 20~30mg KOH / g, 30~150mg KOH / g, 30~140mg KOH / g, 30~130mg KOH / g, 30~120mg KOH / g, 30~110mg KOH / g, 30~100mg KOH / g, 30~90mg KOH / g, 30~80mg KOH / g, 30~70mg KOH / g, 30~60mg KOH / g, 30~50mg KOH / g, 30~40mg KOH / g, 40~150mg KOH / g, 40~140mg KOH / g, 40~130mg KOH / g, 40~120mg KOH / g, 40~110mg KOH / g, 40~100mg KOH / g, 40~90mg KOH / g, 40~80mg KOH / g, 40~70mg KOH / g, 40~60mg KOH / g, 40~50mg KOH / g, 50~150mg KOH / g, 50~140mg KOH / g, 50~130mg KOH / g, 50~120mg KOH / g, 50~110mg KOH / g, 50~100mg KOH / g, 50~90mg KOH / g, 50~80mg KOH / g, 50~70mg KOH / g, 50~60mg KOH / g, 60~150mg KOH / g, 60~140mg KOH / g, 60~130mg KOH / g, 60~120mg KOH / g, 60~110mg KOH / g, 60~100mgIt has a TBN of 60 - 90 mg KOH / g, 60 - 80 mg KOH / g, 60 - 70 mg KOH / g, 80 - 150 mg KOH / g, 80 - 140 mg KOH / g, 80 - 130 mg KOH / g, 80 - 120 mg KOH / g, 80 - 110 mg KOH / g, 80 - 100 mg KOH / g, 80 - 90 mg KOH / g, 90 - 150 mg KOH / g, 90 - 140 mg KOH / g, 90 - 130 mg KOH / g, 90 - 120 mg KOH / g, 90 - 110 mg KOH / g, 90 - 100 mg KOH / g, 100 - 150 mg KOH / g, 100 - 140 mg KOH / g, 100 - 130 mg KOH / g, 100 - 120 mg KOH / g, 100 - 110 mg KOH / g, 110 - 150 mg KOH / g, 110 - 140 mg KOH / g, 110 - 130 mg KOH / g, 110 - 120 mg KOH / g, 120 - 150 mg KOH / g, 120 - 140 mg KOH / g, 120 - 130 mg KOH / g, 130 - 150 mg KOH / g, 130 - 140 mg KOH / g, or 140 - 150 mg KOH / g.

[0020] In some embodiments, the alkylhydroxybenzoic acid detergent has a TBN of 10 - 300 mg KOH / g on an oil - free basis. In some embodiments, the alkylhydroxybenzoic acid detergent has a TBN of 600 mg KOH / g or more on an oil - free basis.

[0021] The synthesis of alkylhydroxybenzoic acid compounds is generally known. For example, one synthetic route for overbased metal alkylhydroxybenzoic acid detergents begins with reacting an alkylphenol with a metal base. Next, the product is carboxylated (i.e., treated with CO2) and acidified. The resulting acid product can be neutralized with lime and overbased. Some of these steps (e.g., the second neutralization and overbasing) can proceed simultaneously. A more detailed description of this process can be found in US8,030,258, which is incorporated herein by reference.

[0022] The counterions of alkylhydroxybenzoic acid detergents are typically alkaline earth metals such as calcium and magnesium. In some embodiments, the lubricating oil composition comprises an alkylhydroxybenzoic acid containing both Ca and Mg.

[0023] In some embodiments, the calcium-containing alkylhydroxybenzoic acid may be present in the lubricating oil composition in an amount providing from about 500 to about 5000 ppm of calcium, such as from about 500 to about 4500 ppm, 500 - 4000 ppm, 500 - 3500 ppm, 500 - 3000 ppm, 500 - 2500 ppm, 500 - 2000 ppm, 500 - 1500 ppm, 500 - 1000 ppm, 1000 - 5000 ppm, 1000 - 4500 ppm, 1000 - 4000 ppm, 1000 - 3500 ppm, 1000 - 3000 ppm, 1000 - 2500 ppm, 1000 - 2000 ppm, 1000 - 1500 ppm, 1500 - 5000 ppm, 1500 - 4500 ppm, 1500 - 4000 ppm, 1500 - 3500 ppm, 1500 - 3000 ppm, 1500 - 2500 ppm, 1500 - 2000 ppm, 2000 - 5000 ppm, 2500 - 4500 ppm, 2500 - 4000 ppm, 2500 - 3500 ppm, 2500 - 3000 ppm, 3000 - 5000 ppm, 3000 - 4500 ppm, 3000 - 4000 ppm, 3000 - 3500 ppm, 3500 - 5000 ppm, 3500 - 4500 ppm, 3500 - 4000 ppm, 4000 - 5000 ppm, 4000 - 4500 ppm, or 4500 - 5000 ppm.

[0024] In some embodiments, the magnesium-containing alkylhydroxybenzoic acid may be present in the lubricating oil composition in an amount providing from about 500 to about 5000 ppm of magnesium, such as from about 500 to about 4500 ppm, 500 to 4000 ppm, 500 to 3500 ppm, 500 to 3000 ppm, 500 to 2500 ppm, 500 to 2000 ppm, 500 to 1500 ppm, 500 to 1000 ppm, 1000 to 5000 ppm, 1000 to 4500 ppm, 1000 to 4000 ppm, 1000 to 3500 ppm, 1000 to 3000 ppm, 1000 to 2500 ppm, 1000 to 2000 ppm, 1000 to 1500 ppm, 1500 to 5000 ppm, 1500 to 4500 ppm, 1500 to 4000 ppm, 1500 to 3500 ppm, 1500 to 3000 ppm, 1500 to 2500 ppm, 1500 to 2000 ppm, 2000 to 5000 ppm, 2500 to 4500 ppm, 2500 to 4000 ppm, 2500 to 3500 ppm, 2500 to 3000 ppm, 3000 to 5000 ppm, 3000 to 4500 ppm, 3000 to 4000 ppm, 3000 to 3500 ppm, 3500 to 5000 ppm, 3500 to 4500 ppm, 3500 to 4000 ppm, 4000 to 5000 ppm, 4000 to 4500 ppm, or 4500 to 5000 ppm of magnesium.

[0025] In some embodiments, the total amount of calcium-containing alkyl hydroxybenzoate and magnesium-containing alkyl hydroxybenzoate is such that the total amount of calcium and magnesium in the lubricating oil composition is from about 500 to about 5000 ppm, for example, from about 500 to about 4500 ppm, 500 to 4000 ppm, 500 to 3500 ppm, 500 to 3000 ppm, 500 to 2500 ppm, 500 to 2000 ppm, 500 to 1500 ppm, 500 to 1000 ppm, 1000 to 5000 ppm, 1000 to 4500 ppm, 1000 to 4000 ppm, 1000 to 3500 ppm, 1000 to 3000 ppm, 1000 to 2500 ppm, 1000 to 2000 ppm, 1000 to 1500 ppm, 1500 to 5000 ppm, 1500 to 4500 ppm, 1500 to 4000 ppm, 1500 to 3500 ppm, 1500 to 3000 ppm, 1500 to 2500 ppm, 1500 to 2000 ppm, 2000 to 5000 ppm, 2500 to 4500 ppm, 2500 to 4000 ppm, 2500 to 3500 ppm, 2500 to 3000 ppm, 3000 to 5000 ppm, 3000 to 4500 ppm, 3000 to 4000 ppm, 3000 to 3500 ppm, 3500 to 5000 ppm, 3500 to 4500 ppm, 3500 to 4000 ppm, 4000 to 5000 ppm, 4000 to 4500 ppm, or 4500 to 5000 ppm.

[0026] Generally, the total amount of Ca and Mg present in the lubricating oil composition is 5000 ppm or less. The ppm value is based on the total weight of the lubricating oil composition.

[0027] Oxidation inhibitor system The lubricating oil composition of the present disclosure includes an oxidation inhibitor system including at least two antioxidant compounds. The antioxidant compounds include (i) a molybdenum-containing antioxidant and (ii) a diphenylamine antioxidant.

[0028] The molybdenum or molybdenum-containing antioxidant is present in an amount to provide the lubricating oil composition with at least 120 ppm Mo, e.g., at least 130 ppm, at least 140 ppm, at least 150 ppm, at least 160 ppm, at least 170 ppm, at least 180 ppm, at least 190 ppm, and at least 200 ppm. Examples of molybdenum-containing antioxidants include molybdenum succinimide, molybdenum dithiocarbamate, and trinuclear molybdenum compounds.

[0029] Molybdenum succinimide In one embodiment, the molybdenum amine is a molybdenum succinimide complex. Suitable molybdenum succinimide complexes are described, for example, in U.S. Patent No. 8,076,275. These complexes are prepared by a process comprising reacting an acidic molybdenum compound with an alkyl or alkenyl succinimide of a polyamine, such as: [ka] In the formula, R is C 24 ~C 350 (For example, C 70 ~C 128 ) alkyl or alkenyl group, R' is a straight or branched chain alkylene group having 2 to 3 carbon atoms, x is 1 to 11, and y is 1 to 11.

[0030] The molybdenum compounds used to prepare molybdenum succinimide complexes are acidic molybdenum compounds or salts of acidic molybdenum compounds. "Acidic" means that the molybdenum compound reacts with basic nitrogen compounds when measured by ASTM D664 or D2896. Generally, acidic molybdenum compounds are hexavalent. Representative examples of suitable molybdenum compounds include molybdenum trioxide, molybdic acid, ammonium molybdate, sodium molybdate, potassium molybdate, and other alkali metal molybdates, and other molybdenum salts, such as hydrogen salts (e.g., sodium hydrogen molybdate), MoOCl4, MoO2Br2, Mo2O3Cl6, etc.

[0031] Succinimides that can be used to prepare molybdenum succinimide complexes have been disclosed in numerous documents and are known in the art. Specific basic types of succinimides and related substances included in the term "succinimide" are taught in U.S. Pat. Nos. 3,172,892, 3,219,666, and 3,272,746. The term "succinimide" is further understood in the art to include many amide, imide, and amidine species that can be formed. However, the main product is succinimide, and this term has come to be recognized as meaning the product of the reaction of an alkyl or alkenyl substituted succinic acid or anhydride with a nitrogen-containing compound. Preferred succinimides are those prepared by reacting a polyisobutenyl succinic anhydride having about 70 to 128 carbon atoms with a polyamine.

[0032] Preferred polyamines can have from 2 to 60 carbon atoms and from 2 to 12 nitrogen atoms per molecule. Particularly preferred amines include polyalkylene amines represented by the following formula: NH2(CH2) n -(NH(CH2) n ) m -NH2 In the formula, n is 2 to 3, and m is 0 to 10. Exemplary examples include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, tetrapropylene pentamine, and pentaethylenehexamine, along with commercially available mixtures of such polyamines.

[0033] The molybdenum succinimide complex can be post-treated with a sulfur source at an appropriate pressure and a temperature not exceeding 120 °C so as to provide a molybdenum sulfide succinimide complex. The sulfidation step can be carried out for a time of about 0.5 to 5 hours (for example, 0.5 to 2 hours). Suitable sulfur sources include elemental sulfur, hydrogen sulfide, phosphorus pentasulfide, an organic polysulfide of the formula R2S x (wherein R is a hydrocarbyl (for example, C1-C 10 alkyl), and x is at least 3), C1-C 10 mercaptan, inorganic sulfides and polysulfides, thioacetamide, and thiourea.

[0034] Molybdenum dithiocarbamate Suitable molybdenum dithiocarbamates include any molybdenum dithiocarbamate that can be used as an additive for lubricating oils. One class of molybdenum dithiocarbamates for use herein is represented by the following,

Chemical formula

[0035] Suitable alkyl groups include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, secondary butyl, tertiary butyl, pentyl, isopentyl, secondary pentyl, neopentyl, tertiary pentyl, hexyl, secondary hexyl, heptyl, secondary heptyl, octyl, 2-ethylhexyl, secondary octyl, nonyl, secondary nonyl, decyl, secondary decyl, undecyl, secondary undecyl, dodecyl, secondary dodecyl, tridecyl, isotridecyl, secondary tridecyl, tetradecyl, secondary tetradecyl, hexadecyl, secondary hexadecyl, stearyl, icosyl, docosyl, tetracosyl, triacontyl, 2-butyloctyl, 2-butyldecyl, 2-hexyloctyl, 2-hexyldecyl, 2-octyldecyl, 2-hexyldodecyl, 2-octyldodecyl, 2-decyltetradecyl, 2-dodecylhexadecyl, 2-hexadecyloctadecyl, 2-tetradecyloctadecyl, monomethyl-branched isostearyl, and the like.

[0036] Suitable alkenyl groups include, but are not limited to, vinyl, allyl, propenyl, butenyl, isobutenyl, pentenyl, isopentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tetradecenyl, oleyl, and the like.

[0037] Suitable aryl groups include, but are not limited to, phenyl, tolyl, xylyl, cumenyl, mesityl, benzyl, phenethyl, styryl, cinnamyl, benzhydryl, trityl, ethylphenyl, propylphenyl, butylphenyl, pentylphenyl, hexylphenyl, heptylphenyl, octylphenyl, nonylphenyl, decylphenyl, undecylphenyl, dodecylphenyl, biphenyl, benzylphenyl, styrenated phenyl, p-cumylphenyl, α-naphthyl, β-naphthyl group, and the like.

[0038] Suitable cycloalkyl and cycloalkenyl groups include, but are not limited to, cyclopentyl, cyclohexyl, cycloheptyl, methylcyclopentyl, methylcyclohexyl, methylcycloheptyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, methylcyclopentenyl, methylcyclohexenyl, methylcycloheptenyl groups, etc.

[0039] In certain embodiments, X 1 ~X 4 is independently selected from sulfur atoms or oxygen atoms, and all of X 1 ~X 4 can be sulfur atoms or oxygen atoms, or a mixture of sulfur atoms and oxygen atoms. Considering the balance between the friction reduction effect and corrosiveness, the molar ratio (ratio of numbers) of sulfur atom(s) / oxygen atom(s) should preferably be in the range of about 1 / 3 to about 3 / 1.

[0040] Some oil-soluble molybdenum compounds or dispersed oil-stable molybdenum compounds are commercially available. For example, when X 1 and X 2 are O, X 3 and X 4 are S, and R 3 ~R 6 are aliphatic hydrocarbyl groups of C 13 H 27 and the molybdenum is in the oxidation state V, the products are sold by R.T. Vanderbilt Company Inc. (Norwalk, Conn., USA) under the trademarks Molyvan 807 and Molyvan 822 as antioxidants and friction reduction additives. Those molybdenum compounds can be prepared by the method described in U.S. Patent No. 3,356,702, in which MoO3 is converted to a soluble molybdate by dissolving in an alkali metal hydroxide solution and neutralized by the addition of an acid followed by the addition of a secondary amine and carbon disulfide. In another aspect, X 1 ~X 4is O or S and can be prepared by several methods known in the art, such as U.S. Patent Nos. 4,098,705 and 5,631,213.

[0041] Generally, molybdenum oxysulfide dithiocarbamate can be prepared by reacting molybdenum trioxide or molybdate with an alkali sulfide or hydrosulfide, then adding carbon disulfide and a secondary amine to the reaction mixture and reacting the resulting mixture at an appropriate temperature. To prepare an asymmetric molybdenum oxysulfide dithiocarbamate, in the above process, it is sufficient to use a secondary amine having different hydrocarbon groups or to use two or more different secondary amines. Symmetric molybdenum oxysulfide dithiocarbamate can also be prepared in a similar manner, but can be prepared by using only one secondary amine.

[0042] Examples of suitable molybdenum dithiocarbamate compounds include molybdenum diethyldithiocarbamate sulfide, molybdenum dipropyldithiocarbamate sulfide, molybdenum dibutyldithiocarbamate sulfide, molybdenum dipentyldithiocarbamate sulfide, molybdenum dihexyldithiocarbamate sulfide, molybdenum dioctyldithiocarbamate sulfide, molybdenum didecyldithiocarbamate sulfide, molybdenum didodecyldithiocarbamate sulfide, molybdenum ditridecyldithiocarbamate sulfide, molybdenum di(butylphenyl)dithiocarbamate sulfide, molybdenum di(nonylphenyl)dithiocarbamate sulfide, molybdenum oxydiethyldithiocarbamate sulfide, molybdenum oxydipropyldithiocarbamate sulfide, molybdenum oxydibutyldithiocarbamate sulfide, molybdenum oxydipentyldithiocarbamate sulfide, molybdenum oxydihexyldithiocarbamate sulfide, molybdenum oxydioctyldithiocarbamate sulfide, molybdenum oxydidecyldithiocarbamate sulfide, molybdenum oxydidodecyldithiocarbamate sulfide, molybdenum oxyditridecyldithiocarbamate sulfide, molybdenum oxydi(butylphenyl)dithiocarbamate sulfide, molybdenum oxydi(nonylphenyl)dithiocarbamate sulfide (in all of these, the alkyl groups may be straight-chain or branched-chain), other similar ones, and mixtures thereof, but are not limited thereto.

[0043] Trinuclear molybdenum compound Suitable molybdenum-containing antioxidants also include trinuclear molybdenum compounds such as trinuclear molybdenum dialkyldithiocarbamates known in the art, as taught in U.S. Pat. Nos. 5,888,945 and 6,010,987, which are incorporated herein by reference.

[0044] In some embodiments, the trinuclear molybdenum compounds may be represented by the formula Mo3S4(dtc)4, Mo3S5(dtc)4, Mo3S4(dtc)6, and Mo3S7(dtc)4, and mixtures thereof, where dtc represents an independently selected diorganodithiocarbamate ligand containing an independently selected organic group, the ligand having a sufficient number of carbon atoms present among all organic groups of the ligand of the compound to render the compound soluble or dispersible in lubricating oil.

[0045] Diphenylamine Diphenylamines are aromatic amine antioxidants that may have one or more carbon-based substituents. Diphenylamine-type oxidation inhibitors include, but are not limited to, alkylated diphenylamines, phenyl-α-naphthylamines, and alkyl- or arylalkyl-substituted phenyl-α-naphthylamines, alkylated p-phenylenediamines, and tetramethyl-diaminodiphenylamine.

[0046] Specific examples of diphenylamine antioxidants include bis-nonylated diphenylamine, bis-octylated diphenylamine, and octylated / butylated diphenylamine, 4,4′-dioctyldiphenylamine, 4,4′-dinonyldiphenylamine, N-phenyl-1-naphthylamine, N-(4-tert-octylphenyl)-1-naphthylamine, and N-(4-octylphenyl)-1-naphthylamine.

[0047] The diphenylamine antioxidant may be present in the lubricating oil composition in an amount of 0.01 to 5 wt%, for example, 0.01 to 4.5 wt%, 0.01 to 4.0 wt%, 0.01 to 3.5 wt%, 0.01 to 3.0 wt%, 0.01 to 2.5 wt%, 0.01 to 2.0 wt%, 0.01 to 1.5 wt%, 0.01 to 1.0 wt%, 0.01 to 0.5 wt%, 0.5 to 5.0 wt%, 0.5 to 4.5 wt%, 0.5 to 4.0 wt%, 0.5 to 3.5 wt%, 0.5 to 3.0 wt%, 0.5 to 2.5 wt%, 0.5 to 2.0 wt%, 0.5 to 1.5 wt%, 0.5 to 1.0 wt%, 1.0 to 5.0 wt%, 1.0 to 4.5 wt%, 1.0 to 4.0 wt%, 1.0 to 3.5 wt%, 1.0 to 3.0 wt%, 1.0 to 2.5 wt%, 1.0 to 2.0 wt%, 1.0 to 1.5 wt%, 1.5 to 5.0 wt%, 1.5 to 4.5 wt%, 1.5 to 4.0 wt%, 1.5 to 3.5 wt%, 1.5 to 3.0 wt%, 1.5 to 2.5 wt%, 1.5 to 2.0 wt%, 2.0 to 5.0 wt%, 2.0 to 4.5 wt%, 2.0 to 4.0 wt%, 2.0 to 3.5 wt%, 2.0 to 3.0 wt%, 2.0 to 2.5 wt%, 2.5 to 5.0 wt%, 2.5 to 4.5 wt%, 2.5 to 4.0 wt%, 2.5 to 3.5 wt%, 2.5 to 3.0 wt%, 3.0 to 5.0 wt%, 3.0 to 4.5 wt%, 3.0 to 4.0 wt%, 3.0 to 3.5 wt%, 3.5 to 5.0 wt%, 3.5 to 4.5 wt%, 3.5 to 4.0 wt%, 4.0 to 5.0 wt%, 4.0 to 4.5 wt%, or 4.5 to 5.0 wt%.

[0048] Any additive Optionally, the lubricating oil composition may contain a hindered phenol antioxidant. Examples of hindered phenol antioxidants include 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-p-cresol, and 2,6-di-tert-butyl-4-(2-octyl-3-propanoic)phenol.

[0049] The hindered phenolic antioxidant is present in the lubricating oil composition in an amount of 0.01 to 5 wt%, for example, 0.01 to 4.5 wt%, 0.01 to 4.0 wt%, 0.01 to 3.5 wt%, 0.01 to 3.0 wt%, 0.01 to 2.5 wt%, 0.01 to 2.0 wt%, 0.01 to 1.5 wt%, 0.01 to 1.0 wt%, 0.01 to 0.5 wt%, 0.5 to 5.0 wt%, 0.5 to 4.5 wt%, 0.5 to 4.0 wt%, 0.5 to 3.5 wt%, 0.5 to 3.0 wt%, 0.5 to 2.5 wt%, 0.5 to 2.0 wt%, 0.5 to 1.5 wt%, 0.5 to 1.0 wt%, 1.0 to 5.0 wt%, 1.0 to 4.5 wt%, 1.0 to 4.0 wt%, 1.0 to 3.5 wt%, 1.0 to 3.0 wt%, 1.0 to 2.5 wt%, 1.0 to 2.0 wt%, 1.0 to 1.5 wt%, 1.5 to 5.0 wt%, 1.5 to 4.5 wt%, 1.5 to 4.0 wt%, 1.5 to 3.5 wt%, 1.5 to 3.0 wt%, 1.5 to 2.5 wt%, 1.5 to 2.0 wt%, 2.0 to 5.0 wt%, 2.0 to 4.5 wt%, 2.0 to 4.0 wt%, 2.0 to 3.5 wt%, 2.0 to 3.0 wt%, 2.0 to 2.5 wt%, 2.5 to 5.0 wt%, 2.5 to 4.5 wt%, 2.5 to 4.0 wt%, 2.5 to 3.5 wt%, 2.5 to 3.0 wt%, 3.0 to 5.0 wt%, 3.0 to 4.5 wt%, 3.0 to 4.0 wt%, 3.0 to 3.5 wt%, 3.5 to 5.0 wt%, 3.5 to 4.5 wt%, 3.5 to 4.0 wt%, 4.0 to 5.0 wt%, 4.0 to 4.5 wt%, or 4.5 to 5.0 wt%.

[0050] Succinimide Optionally, the lubricating oil composition may contain a polyalkenyl succinimide dispersant such as those described herein. Generally, the nitrogen content from the nitrogen-containing dispersant based on the lubricating oil composition is about 0.010 wt% to about 0.30 wt%, for example, about 0.050 to about 0.25 wt%, about 0.050 to about 0.20 wt%, and about 0.050 to about 0.15 wt%, etc.

[0051] In one embodiment, the polyalkenyl bis-succinimide is the following polyalkenyl-substituted succinic anhydride

Chemical formula

[0052] Suitable polyamines for use in the preparation of bis-succinimide dispersants include polyalkylene polyamines. Such polyalkylene polyamines typically contain about 2 to about 12 nitrogen atoms and about 2 to 24 carbon atoms. Particularly suitable polyalkylene polyamines are those having the formula: H2N-(R’NH)x-H, where R’ is a straight-chain or branched-chain alkylene group having 2 or 3 carbon atoms and x is 1 to 9. Representative examples of suitable polyalkylene polyamines include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and heavy polyamines (e.g., Ethyleneamine E-100 available from Huntsman Company).

[0053] Generally, the polyalkenyl-substituted succinic anhydride is reacted with the polyamine at a temperature of about 130°C to about 220°C (e.g., 145°C to 175°C). The reaction can be carried out under an inert atmosphere such as nitrogen or argon. Generally, a suitable molar charge of the polyamine and the polyalkenyl-substituted succinic anhydride is about 0.35:1 to about 0.6:1 (e.g., 0.4:1 to 0.5:1). As used herein, the “molar charge of the polyamine and the polyalkenyl-substituted succinic anhydride” means the ratio of the number of moles of the polyamine to the number of succinic acid groups in the succinic anhydride reactant.

[0054] One class of suitable polyalkenyl succinimides can be represented by the following, [Chemical Formula] wherein R and R' are as described above herein, and y is from 1 to 11.

[0055] Work-up of Polyalkenyl Succinimide In some embodiments, the succinimide dispersant can be worked up with a reactive boron compound or an organic carbonate.

[0056] Suitable boron compounds that can be used as a boron source include, for example, boric acid, borates, and borate esters. Representative examples of boric acid include orthoboric acid, metaboric acid, and para-boric acid. Representative examples of borates include ammonium borates, such as ammonium metaborate, ammonium tetraborate, ammonium pentaborate, and ammonium octaborate. Representative examples of borate esters include monomethyl borate, dimethyl borate, trimethyl borate, monoethyl borate, diethyl borate, triethyl borate, monopropyl borate, dipropyl borate, tripropyl borate, monobutyl borate, dibutyl borate, and tributyl borate.

[0057] In some embodiments, the lubricating oil composition includes both boronated succinimide and non-boronated succinimide. In some embodiments, the mass ratio of boronated succinimide to non-boronated succinimide is less than 1, such as less than 0.95, less than 0.90, less than 0.85, and less than 0.80.

[0058] Lubricating Oil Lubricating viscosity oils (sometimes referred to as "base stocks" or "base oils") are the main liquid components of lubricating oils, to which additives and sometimes other oils are blended to produce, for example, the final lubricating oil (or lubricating oil composition). Base oils useful for producing concentrates and from which lubricating oil compositions can be produced may be selected from natural (vegetable, animal, or mineral) and synthetic lubricating oils and mixtures thereof.

[0059] The oils used as base oils are selected or blended according to the desired end use and additives in the finished oil to obtain the desired grade of engine oil. In one embodiment, the lubricating oil composition is a multigrade oil for large vehicles or passenger cars. Multigrade oils are in the viscosity grades of the Society of Automotive Engineers (SAE) and can have 0W-8, 0W-12, 0W-16, 0W-20, 0W-30, 0W-40, 0W-50, 0W-60, 5W, 5W-20, 5W-30, 5W-40, 5W-50, 5W-60, 10W, 10W-20, 10W-30, 10W-40, 10W-50, 15W, 15W-20, 15W-30, 15W-40, 20W-40 or 20W-50.

[0060] The definitions of base stocks and base oils in the present disclosure are the same as those found in American Petroleum Institute (API) Publication 1509 Annex E (“API Base Oil Interchangeability Guidelines for Passenger Car Motor Oils and Diesel Engine Oils,” February 2022). Group I base stocks contain less than 90% saturates and / or more than 0.03% sulfur and have a viscosity index of 80 or more and less than 120 using the test methods defined in Table E-1. Group II base stocks contain 90% or more saturates and 0.03% or less sulfur and have a viscosity index of 80 or more and less than 120 using the test methods defined in Table E-1. Group III base stocks contain 90% or more saturates and 0.03% or less sulfur and have a viscosity index of 120 or more using the test methods defined in Table E-1. Group IV base stocks are polyalphaolefins (PAOs). Group V base stocks include all other base stocks not included in Group I, II, III, or IV.

[0061] Natural oils include animal oils, vegetable oils (e.g., castor oil and lard oil), and mineral oils. Animal and vegetable oils with favorable thermal oxidation stability can be used. Among natural oils, mineral oils are preferred. Mineral oils vary widely depending on their crude source, for example, whether paraffinic, naphthenic, or a mixture of paraffinic and naphthenic. Oils derived from coal or shale are also useful. Natural oils also vary depending on the methods used in their production and refining, for example, their distillation range, and whether they are straight-run, cracked, hydrorefined, or solvent-extracted.

[0062] Synthetic oils include hydrocarbon oils. Examples of hydrocarbon oils include oils such as polymerized and copolymerized olefins (e.g., polybutylene, polypropylene, propylene isobutylene copolymer, ethylene-olefin copolymer, and ethylene-alpha olefin copolymer). Polyalphaolefin (PAO) oil base stocks are commonly used synthetic hydrocarbon oils. As an example, PAO derived from C8 to C 14 olefins, such as C8, C 10 , C 12 , C 14 olefins, or mixtures thereof can be utilized.

[0063] Other useful fluids for use as base oils include non-conventional or unaccustomed base stocks that have been (preferably catalytically) treated or synthesized to impart high-performance characteristics.

[0064] Non-conventional or unaccustomed base stocks / base oils include base stock(s) derived from one or more gas-to-liquid (GTL) materials, as well as natural waxes or waxy feedstocks, mineral oil and / or non-mineral oil waxy feedstocks, e.g., slack wax, natural wax, and waxy stocks such as gas oil, residues from hydrocracking of waxy fuels, waxy raffinates, hydrocracked oils, pyrolysis oils, or other mineral, mineral oils, or even non-petroleum-derived waxy materials, e.g., waxy materials obtained from coal liquefaction or shale oil, mixtures of isomerized / isomerized dewaxed base stock(s) derived therefrom, and one or more of mixtures of these base stocks. Other base oils include coal-to-liquid (CTL) products and alkylnaphthalenes.

[0065] The base oil for use in the lubricating oil composition of the present disclosure is any of various oils corresponding to API Group I, Group II, Group III, Group IV, and Group V oils, and mixtures thereof, with Group II, Group III, Group IV, and Group V oils, and mixtures thereof being preferred, and Group III to Group V base oils being more preferred due to their excellent volatility, stability, viscosity, and cleanliness characteristics.

[0066] The lubricating oil composition may have a high temperature high shear (HTHS) viscosity at 150 °C of 5.2 cP or less, for example, 5.1 cP or less, 5.0 cP or less, 4.5 cP or less, 4.0 cP or less, 3.9 cP or less, 3.8 cP or less, 3.7 cP or less, 3.6 cP or less, 3.5 cP or less, 3.4 cP or less, 3.3 cP or less, 3.2 cP or less, 3.1 cP or less, 3.0 cP or less, 2.9 cP or less, 2.8 cP or less, 2.7 cP or less, 2.6 cP or less, 2.5 cP or less, 2.4 cP or less, 2.3 cP or less, 2.2 cP or less, 2.1 cP or less, 2.0 cP or less, 1.9 cP or less, 1.8 cP or less, 1.7 cP or less, 1.6 cP or less, 1.5 cP or less, 1.4 cP or less, 1.3 cP or less, 1.2 cP or less, 1.1 cP or less, or 1.0 cP or less. In some embodiments, the lubricating oil composition may have an HTHS at 150 °C of 1.0 to 5.2 cP, for example, 1.0 to 4.5 cP, 1.0 to 4.0 cP, 1.0 to 2.9 cP, 1.3 to 2.9 cP, 1.0 to 2.6 cP, 1.3 to 2.6 cP, 1.0 cP to 2.3 cP, 1.3 cP to 2.3 cP, 1.0 cP to 2.0 cP, 1.3 cP to 2.3 cP, 1.0 cP to 1.7 cP, or 1.3 cP to 1.7 cP. The lubricating oil composition may have a viscosity index of at least 135 (e.g., 135 to 400, or 135 to 250), at least 150 (e.g., 150 to 400, 150 to 250), at least 165 (e.g., 165 to 400, or 165 to 250), at least 190 (e.g., 190 to 400, or 190 to 250), or at least 200 (e.g., 200 to 400, or 200 to 250). If the viscosity index of the lubricating oil composition is less than 135, it may be difficult to improve fuel efficiency while maintaining the HTHS viscosity at 150 °C. If the viscosity index of the lubricating oil composition exceeds 400, the evaporation characteristics may decrease, and defects may occur due to insufficient solubility of additives and poor matching with seal materials.

[0067] The base oil has a kinematic viscosity (ASTM D445) at 100 o °C in the range of 1.4 to 20 mm 2 / s, for example, 3 to 12 mm 2 / s, for example, 3 to 11 mm 2 / s, 3 to 10 mm 2 / s, 3 to 9 mm 2 / s, 3 to 8 mm 2 / s, 3 to 7 mm 2 / s, 3 to 6 mm 2 / s, 3 to 5 mm 2 / s, 3 to 4 mm 2 / s, 4 to 12 mm 2 / s, 4 to 11 mm 2 / s, 4 to 10 mm 2 / s, 4 to 9 mm 2 / s, 4 to 8 mm 2 / s, 4 to 7 mm 2 / s, 4 to 6 mm 2 / s, 4 to 5 mm 2 / s, 5 to 12 mm 2 / s, 5 to 11 mm 2 / s, 5 to 10 mm 2 / s, 5 to 9 mm 2 / s, 5 to 8 mm 2 / s, 5 to 7 mm 2 / s, 5 to 6 mm 2 / s, 6 to 12 mm 2 / s, 6 to 11 mm 2 / s, 6 to 10 mm 2 / s, 6 to 9 mm 2 / s, 6 to 8 mm 2 / s, 6 to 7 mm 2 / s, 7 to 12 mm 2 / s, 7 to 11 mm 2 / s, 7 to 10 mm 2 / s, 7 to 9 mm 2 / s, 7 to 10 mm 2 / s, 7 to 9 mm 2 / s, 7 to 8 mm 2 / s, 8 to 12 mm 2 / s, 8 to 11 mm 2 / s, 8 to 10 mm 2 / s, 8 to 9 mm 2 / s, 9 to 12 mm 2 / s, 9 to 11 mm 2 / s, 9 to 10 mm 2 / s, 10 to 12 mm 2 / s, 10 to 11 mm 2 / s, or 11 to 12 mm 2 / s may be.

[0068] Other additives The lubricating oil composition of the present invention may also contain conventional lubricating oil additives for imparting auxiliary functions, and a finished lubricating oil composition in which these additives are dispersed or dissolved may be obtained. For example, the lubricating oil composition may contain antioxidants, ashless dispersants, antiwear agents, rust inhibitors, cloud point depressants, demulsifiers, friction modifiers, metal deactivators, pour point depressants, viscosity modifiers, antifoaming agents, cosolvents, package compatibilizers, corrosion inhibitors, dyes, extreme pressure agents, etc., and mixtures thereof. Various additives are known and commercially available. These additives or their similar compounds can be used in the preparation of the lubricating oil composition of the present invention by ordinary compounding procedures.

[0069] Each of the aforementioned additives, when used, is used in a functionally effective amount to impart the desired properties to the lubricating oil. Thus, for example, when the additive is an ashless dispersant, the functionally effective amount of this ashless dispersant is an amount sufficient to impart the desired dispersion properties to the lubricating oil. Generally, the concentration of each of these additives, when used, can be in the range of about 0.001 to about 20 wt%, for example, about 0.01 to about 10 wt%, unless otherwise specified.

[0070] The following non-limiting examples are illustrative of the present invention. A brief description of the method for preparing the examples is provided.

Examples

[0071] Each sample described herein contained a dispersant inhibitor package containing one or more of the following: Dispersant inhibitor package 1) Dispersant 2) Antiwear agent 3) Detergent 4) Antioxidant 5) Optional friction modifier 6) Optional corrosion inhibitor The fully formulated lubricating oil composition contains a dispersant inhibitor package and a base oil. The composition may also contain a viscosity index improver and a pour point depressant.

[0072] The following describes the specific detergent components used. The salicylate detergents (A, B, D) were synthesized according to, or substantially according to, the method described in U.S. Patent No. 8,993,499. The salicylate detergent C was synthesized according to, or substantially according to, the method described in U.S. Patent No. 8,030,258. The isomerized normal alpha olefin was obtained as a commercial product from CP Chem.

[0073] Salicylate A Salicylate A was prepared by alkylating with a C20 - 24 isomerized normal alpha olefin. The isomerization level of the alpha olefin is about 0.16. The TBN of the resulting alkylhydroxybenzoic acid composition is about 225 mg KOH / g, and the Ca content is 8 wt% on an oil - free basis.

[0074] Salicylate B Salicylate B was prepared by alkylating with a C20 - 24 isomerized normal alpha olefin. The isomerization level of the alpha olefin is about 0.16. The TBN of the resulting alkylhydroxybenzoic acid composition is about 630 mg KOH / g, and the Ca content is 22 wt% on an oil - free basis.

[0075] Salicylate C Salicylate C was prepared by alkylating with a C20 - 28 normal alpha olefin. The TBN of the resulting alkylhydroxybenzoic acid composition is about 520 mg KOH / g, and the Ca content is 19 wt% on an oil - free basis.

[0076] Salicylate D Salicylate D was prepared by alkylating with a C14 - C18 normal alpha olefin. The TBN of the resulting alkylhydroxybenzoic acid composition is about 300 mg KOH / g, and the Ca content is about 10.6 wt% on an oil - free basis.

[0077] Ca Sulfonate 1 Calcium sulfonate 1 is a low overbased calcium sulfonate with a TBN of approximately 35 mg KOH / g and a Ca content of approximately 4.4 wt% on an oil-free basis.

[0078] Calcium sulfonate 2 Calcium sulfonate 2 is a highly overbased calcium sulfonate with a TBN of approximately 700 mg KOH / g and a Ca content of approximately 26 wt% on an oil-free basis.

[0079] Magnesium sulfonate Magnesium sulfonate is a moderately overbased sulfonate with a TBN of approximately 656 mg KOH / g and a Mg content of approximately 15.4 wt% on an oil-free basis.

[0080] Phenate Phenate is a highly overbased calcium phenate with a TBN of approximately 383 mg KOH / g and a Ca content of approximately 14 wt% on an oil-free basis.

[0081] HTCBT test Using the ASTM D6594 HTCBT protocol, lubricants for diesel engines were tested to measure their tendency to corrode various metals. Four types of metal samples, copper, lead, tin, and phosphor bronze, were immersed in a measured amount of engine oil. Air (5 l / h) was blown into the oil at a high temperature (170 °C) for a certain period of time (168 hours). Thereafter, the copper test pieces and the stressed oil were inspected respectively to detect corrosion and corrosion products.

[0082] The concentrations of copper, lead, and tin in the new oil and the stressed oil, and the changes in the respective metal concentrations are reported below.

Table 1

[0083] For the sake of brevity, only certain ranges are explicitly disclosed in this specification. However, ranges from any lower limit can be combined with any upper limit to describe ranges not explicitly recited, and similarly, ranges from any lower limit can be combined with any other lower limit to describe ranges not explicitly recited, and similarly, ranges from any upper limit can be combined with any other upper limit to describe ranges not explicitly recited. Further, within a range, all points or individual values between its endpoints are included even if not explicitly recited. Thus, all points or individual values can be combined with any other point or individual value, or any other lower or upper limit, to function as its own lower or upper limit and describe ranges not explicitly recited.

[0084] Similarly, the term "comprising" is considered synonymous with the term "including". Similarly, whenever there is a transitional phrase "comprising" before a composition, element, or group of elements, it is always understood to also contemplate the same composition or group of elements with a transitional phrase "consisting essentially of", "consisting of", "selected from the group consisting of", or "being" before the description of the composition, element, or group of elements, and vice versa.

[0085] As used herein, the terms "a" and "the" are understood to include both the singular and the plural forms.

[0086] Various terms are defined above. To the extent that a term used in a claim is not defined above, the broadest definition given to that term by an expert in the relevant art should be given, as in at least one printed publication or issued patent. Further, all patents, test methods, and other documents cited in this application are hereby incorporated by reference in their entirety to the extent that such disclosure is not inconsistent with this application and in all jurisdictions in which such incorporation is permitted.

[0087] The above description of the present disclosure is illustrative and explanatory of the present disclosure. Further, while the present disclosure shows and describes only preferred embodiments, as described above, the present disclosure is applicable in other various combinations, modifications, and environments, and within the scope of the concepts expressed herein, it should be understood that changes or modifications commensurate with the above teachings and / or the skills or knowledge of the related art are possible. The above is directed to embodiments of the present disclosure, but other further embodiments of the present disclosure can be devised without departing from the basic scope of the present disclosure, and the scope of the present disclosure is determined by the following claims.

[0088] When combinations, subsets, groups, etc. of elements are disclosed (e.g., combinations of components in a composition or combinations of steps in a method), specific references to each of the various individual and collective combinations and permutations of these elements may not be explicitly disclosed, but each is specifically contemplated and described herein.

[0089] The embodiments described above in this specification are further intended to describe the best mode known for carrying them out and to enable others skilled in the art to utilize the present disclosure with various modifications required for such or other embodiments for a particular application or use. Accordingly, this description is not intended to be limiting to the forms disclosed herein. Also, the appended claims are intended to be construed to include alternative embodiments.

Claims

Claim 1 A lubricating oil composition comprising: a major amount of an oil of lubricating viscosity, one or more alkylhydroxybenzoic acid compounds derived from isomerized normal alpha-olefins, and an antioxidant system comprising a molybdenum-containing antioxidant and diphenylamine, wherein the molybdenum-containing antioxidant is present in an amount providing at least 120 ppm of Mo to the lubricating oil composition, and the diphenylamine is present in an amount providing 0.5 wt% or more to the lubricating oil composition. Claim 2 The lubricating oil composition according to claim 1, wherein the alkylhydroxybenzoic acid compound has a TBN of 10 to 300 mg KOH / g on an oil-free basis. Claim 3 The lubricating oil composition according to claim 1, wherein the one or more alkylhydroxybenzoic acid compounds have a TBN of 600 mg KOH / g or more on an oil-free basis. Claim 4 The lubricating oil composition according to claim 1, wherein the one or more alkylhydroxybenzoic acid compounds are a mixture of an alkylhydroxybenzoic acid compound having a TBN of 10 to 300 mg KOH / g on an oil-free basis and an alkylhydroxybenzoic acid compound having a TBN of 600 mg KOH / g or more on an oil-free basis. Claim 5 The lubricating oil composition according to claim 1, wherein the molybdenum-containing antioxidant is a molybdenum succinimide, a molybdenum dithiocarbamate, or a trinuclear molybdenum compound. Claim 6 The lubricating oil composition according to claim 1, further comprising a friction modifier, a viscosity index improver, a corrosion inhibitor, or a pour point depressant. Claim 7 The lubricating oil composition according to claim 1, wherein the isomerized normal alpha-olefin contains 10 to 40 carbon atoms. Claim 8 A method for reducing copper corrosion in an engine, the method comprising lubricating the engine with a lubricating oil composition comprising: a major amount of an oil of lubricating viscosity, one or more alkylhydroxybenzoic acid compounds derived from isomerized normal alpha-olefins, and an antioxidant system comprising a molybdenum-containing antioxidant and diphenylamine, wherein the molybdenum-containing antioxidant is present in an amount providing at least 120 ppm of Mo to the lubricating oil composition, and the diphenylamine is present in an amount providing 0.5 wt% or more to the lubricating oil composition. Claim 9 The method according to claim 8, wherein the alkylhydroxybenzoic acid compound has a TBN of 10 to 300 mg KOH / g on an oil-free basis.

10. The method according to claim 8, wherein the one or more alkylhydroxybenzoic acid compounds have a TBN of 600 mg KOH / g or more on an oil-free basis.

11. The method according to claim 8, wherein the one or more alkylhydroxybenzoic acid compounds is a mixture of an alkylhydroxybenzoic acid compound having a TBN of 10 to 300 mg KOH / g on an oil-free basis and an alkylhydroxybenzoic acid compound having a TBN of 600 mg KOH / g or more on an oil-free basis.

12. The method according to claim 8, wherein the molybdenum-containing antioxidant is molybdenum succinimide, molybdenum dithiocarbamate, or a trinuclear molybdenum compound.

13. The method according to claim 1, wherein the lubricating oil composition further comprises a friction modifier, a viscosity index improver, a corrosion inhibitor, or a pour point depressant.

14. The method according to claim 8, wherein the isomerized normal alpha olefin contains 10 to 40 carbon atoms.

15. A lubricating oil composition comprising: a major amount of an oil of lubricating viscosity; one or more alkylhydroxybenzoic acid compounds derived from C10 - C40 isomerized normal alpha olefins; and an antioxidant system comprising a molybdenum-containing antioxidant and diphenylamine; wherein the molybdenum-containing antioxidant is present in an amount that provides at least 120 ppm of Mo to the lubricating oil composition, and the diphenylamine is present in an amount that provides 0.5 wt% or more to the lubricating oil composition.

16. The lubricating oil composition according to claim 15, wherein the alkylhydroxybenzoic acid compound has a TBN of 10 to 300 mg KOH / g on an oil-free basis.

17. The lubricating oil composition according to claim 15, wherein the one or more alkylhydroxybenzoic acid compounds have a TBN of 600 mg KOH / g or more on an oil-free basis.

18. The lubricating oil composition according to claim 15, wherein the one or more alkylhydroxybenzoic acid compounds is a mixture of an alkylhydroxybenzoic acid compound having a TBN of 10 to 300 mg KOH / g on an oil-free basis and an alkylhydroxybenzoic acid compound having a TBN of 600 mg KOH / g or more on an oil-free basis.

19. The lubricating oil composition according to claim 15, wherein the molybdenum-containing antioxidant is a molybdenum succinimide, a molybdenum dithiocarbamate, or a trinuclear molybdenum compound.

20. The lubricating oil composition according to claim 15, further comprising a friction modifier, a viscosity index improver, a corrosion inhibitor, or a pour point depressant.

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