JP7749541B2 - lubricating oil composition - Google Patents

Description

Engine lubricant requirements are becoming more demanding to keep up with modern engine designs. One such requirement is the desire for stronger antioxidant properties, which has increased the search for new antioxidants. Oxidation of engine oils adversely affects the performance of lubricant additives and shortens the performance life of engine oils.

According to one embodiment of the present disclosure, there is provided a lubricating oil composition comprising:
Lubricating oil compositions are provided that include: (a) a major amount of oil of lubricating viscosity; and (b) one or more detergents including at least one alkyl hydroxybenzoate compound derived from isomerized NAO having from about 10 to about 40 carbon atoms; and (c) an ashless sulfur compound, wherein the ashless sulfur compound is not a dithiocarbamate.

Also provided is a method of lubricating an engine, comprising:
(a) a major amount of oil of lubricating viscosity;
(b) one or more detergents comprising at least one alkyl hydroxybenzoate compound derived from isomerized NAO having from about 10 to 40 carbon atoms; and (c) an ashless sulfur compound, wherein the ashless sulfur compound is not a dithiocarbamate.
Although overlapping with other descriptions, various aspects of the present invention are as follows: However, the present invention is not limited to the following.
[1]
1. A lubricating oil composition comprising:
(a) a major amount of oil of lubricating viscosity;
(b) one or more detergents comprising at least one alkyl hydroxybenzoate compound derived from isomerized normal alpha olefins (NAO) having from about 10 to about 40 carbon atoms; and
(c) an ashless sulfur compound, wherein the ashless sulfur compound is not a dithiocarbamate.
wherein the alkyl hydroxybenzoate compound has a TBN of at least 600 mg KOH/gm on an actives basis.
[2]
The lubricating oil composition of [1], wherein the TBN of the alkyl hydroxybenzoate compound is 600 to 800 mg KOH/gm on an active matter basis.
[3]
2. The lubricating oil composition of claim 1, wherein the one or more detergents are alkali or alkaline earth metal alkylhydroxybenzoates derived from alkyl groups having 20 to 28 carbon atoms.
[4]
2. The lubricating oil composition of claim 1, wherein the isomerized normal alpha olefin has an isomerization level (I) of the normal alpha olefin of about 0.1 to about 0.4.
[5]
2. The lubricating oil composition of claim 1, wherein the alkyl hydroxybenzoate detergent is a calcium alkyl hydroxybenzoate derived from isomerized NAO.
[6]
The lubricating oil composition of claim 1, wherein the ashless sulfur compound is selected from sulfurized fatty esters, sulfurized olefins, thiadiazoles, sulfurized olefins, ashless dithiophosphates, sulfurized phenols, and phenothiazines.
[7]
1. A method of lubricating an engine, comprising:
(a) a major amount of an oil of lubricating viscosity, and
(b) one or more detergents comprising at least one alkyl hydroxybenzoate compound derived from isomerized normal alpha olefins (NAO) having from about 10 to about 40 carbon atoms; and
(c) an ashless sulfur compound, wherein the ashless sulfur compound is not a dithiocarbamate.
wherein the alkyl hydroxybenzoate compound has a TBN of at least 600 mg KOH/gm on an actives basis.
[8]
The method of claim 7, wherein the TBN of the alkyl hydroxybenzoate compound is 600 to 800 mg KOH/gm on an active matter basis.
[9]
8. The method of claim 7, wherein the ashless sulfur compound is a sulfurized fatty ester, a sulfurized olefin, a thiadiazole, a sulfurized olefin, an ashless dithiophosphate, a sulfurized phenol, and a phenothiazine, or a combination thereof.
[10]
8. The method of claim 7, wherein the one or more detergents are alkali or alkaline earth metal alkylhydroxybenzoates derived from alkyl groups having 20 to 28 carbon atoms.
[11]
8. The method of claim 7, wherein the isomerized normal alpha olefin has an isomerization level (I) of the normal alpha olefin of about 0.1 to about 0.4.
[12]
8. The method of claim 7, wherein the alkyl hydroxybenzoate detergent is a calcium alkyl hydroxybenzoate derived from isomerized NAO.
[13]
8. The method of claim 7, wherein oxidation of the lubricating oil in an engine is reduced.

While the present invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been described in detail herein. However, the description of specific embodiments herein is not intended to limit the invention to the particular forms disclosed, but on the contrary, is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

To facilitate understanding of the subject matter disclosed herein, numerous terms, abbreviations, or other abbreviations used herein are defined below. Any term, abbreviation, or other abbreviation not defined will be understood to have its ordinary meaning as used by one of ordinary skill in the art contemporaneously with the filing of this application.

DEFINITIONS As used herein, the following terms have the following meanings unless expressly stated to the contrary: As used herein, the following terms and expressions, if used, have the meanings provided below.

"Major amount" means greater than 50% by weight of the composition.

"Minor amount" means less than 50% by weight of the composition, expressed with respect to the stated additive and with respect to the total mass of all additives present in the composition, calculated as the active ingredient of the additive(s).

"Active ingredient" or "active substance" or "oil-free" refers to an added substance that is not a diluent or solvent.

All percentages reported are by weight on an active ingredient basis (i.e., without regard to carrier or diluent oil) unless otherwise stated.

The abbreviation "ppm" means parts per million by weight, based on the total weight of the lubricating oil composition.

Total base number (TBN) was determined according to ASTM D2896.

Metal - The term "metal" refers to an alkali metal, alkaline earth metal, or mixtures thereof.

High temperature, high shear (HTHS) viscosity at 150°C was determined according to ASTM D4863.

Kinematic viscosity at 100° C. (KV ₁₀₀ ) was determined according to ASTM D445.

Cold cranking simulator (CCS) viscosity at -35°C was determined according to ASTM D5293.

Olefins - The term "olefin" refers to a class of unsaturated aliphatic hydrocarbons with one or more carbon-carbon double bonds, obtained by many processes. Those containing one double bond are called monoalkenes, and those with two double bonds are called dienes, alkyldienes, or diolefins. Alpha olefins are particularly reactive because the double bond is between the first and second carbon. Examples are 1-octene and 1-octadecene, which are used as starting points for moderately biodegradable surfactants. Linear and branched olefins are also included in the definition of olefins.

Normal alpha olefin - The term "normal alpha olefin" refers to an olefin that is a straight-chain, unbranched hydrocarbon with carbon-carbon double bonds present at both the beginning and end of the chain.

Isomerized normal alpha olefins. As used herein, the term "isomerized normal alpha olefins" refers to alpha olefins that have been subjected to isomerization conditions that result in a change in the distribution of olefin species present and/or the introduction of branching along the alkyl chain. Isomerized olefin products can be obtained by isomerizing linear alpha olefins containing from about 10 to about 40 carbon atoms, preferably from about 20 to about 28 carbon atoms, and preferably from about 20 to about 24 carbon atoms.

All ASTM standards referenced herein are the latest versions as of the filing date of this application.

This disclosure describes a lubricating oil composition comprising a combination of an alkyl hydroxybenzoate detergent and an ashless sulfur compound, the combination synergistically controlling oxidation of engine oils.

In one aspect, the present disclosure provides a lubricating oil composition comprising:
The present invention relates to a lubricating oil composition comprising: (a) a major amount of oil of lubricating viscosity; and (b) one or more detergents comprising at least one alkyl hydroxybenzoate compound derived from an isomerized normal alpha olefin having from about 10 to 40 carbon atoms; and (c) an ashless sulfur compound, wherein the ashless sulfur compound is not a dithiocarbamate.

In another aspect, a method of lubricating an engine comprises:
A method is provided that includes lubricating with a lubricating oil composition that includes: (a) a major amount of oil of lubricating viscosity; and (b) one or more detergents that include at least one alkyl hydroxybenzoate compound derived from an isomerized normal alpha olefin having from about 10 to 40 carbon atoms; and (c) an ashless sulfur compound, wherein the ashless sulfur compound is not a dithiocarbamate.

Alkyl hydroxybenzoate detergent compounds derived from C10-C40 isomerized normal alpha olefins (NAO)

In one aspect of the disclosure, the alkyl hydroxybenzoate detergent derived from _C10 - _C40 isomerized NAO has a TBN of from about 100 to about 700, e.g., from about 100 to about 650, from about 100 to about 600, from about 100 to about 500, from about 100 to about 400, from about 100 to 300, from about 150 to 250, from about 175 to about 250, or from about 175 to about 225 mg KOH/gram on an oil-free basis.

In one aspect of the disclosure, the alkyl hydroxybenzoate detergent is derived from _C10 - _C40 isomerized NAO and has a TBN on an actives basis of about 10 to about 300, e.g., about 50 to about 300, about 100 to about 300, about 150 to about 300, and about 175 to about 250 mg KOH/gram.

In one aspect of the disclosure, the C ₁₀ -C ₄₀ isomerized NAO derived alkyl hydroxybenzoate detergent is a Ca alkyl hydroxybenzoate detergent.

In one aspect of the disclosure, the alkyl hydroxybenzoate detergent derived from C ₁₀ -C ₄₀ isomerized NAO may be an alkylated hydroxybenzoate detergent, hi another embodiment, the detergent may be a salicylate detergent.

In one aspect of the present disclosure, alkyl hydroxybenzoates derived from C ₁₀ -C ₄₀ isomerized NAO can be prepared as described in US Pat. No. 8,993,499, which is incorporated herein in its entirety.

In one aspect of the present disclosure, the alkyl hydroxybenzoate detergent is produced from a phenol having an alkyl group derived from an isomerized alpha olefin having about 10 to about 40 carbon atoms per molecule, e.g., about 14 to about 28 carbon atoms per molecule, about 20 to about 24 carbon atoms per molecule, about 14 to about 18 carbon atoms, and about 20 to about 28 carbon atoms per molecule.

In one aspect of the disclosure, alkyl hydroxybenzoates derived from C ₁₀ -C ₄₀ isomerized NAO are produced from alkylphenols having alkyl groups derived from isomerized NAO having an isomerization level (I) of from about 0.10 to about 0.40, e.g., from about 0.10 to about 0.35, from about 0.10 to about 0.30, from about 0.12 to about 0.30, and from about 0.12 to about 0.20.

In one aspect of the disclosure, alkyl hydroxybenzoates derived from C ₁₀ -C ₄₀ isomerized NAO are produced from one or more alkylphenols having alkyl groups derived from C ₁₀ -C ₄₀ isomerized NAO and one or more alkylphenols having alkyl groups different from the C ₁₀ -C ₄₀ isomerized NAO.

In one aspect of the present disclosure, the isomerized NAO alkyl hydroxybenzoate detergent has an isomerization level of about 0.16 and has from about 20 to about 24 carbon atoms.

In one aspect of the present disclosure, the isomerized NAO alkyl hydroxybenzoate detergent has an isomerization level of about 0.26 and has from about 20 to about 24 carbon atoms.

Alkyl hydroxybenzoate detergents derived from _C10 - _C40 isomerized NAO may contain alkali or alkaline earth metals (e.g., barium, sodium, potassium, lithium, calcium, and magnesium). The most commonly used metals are calcium and magnesium (both of which may be present in detergents used in lubricants), and mixtures of calcium and/or magnesium with sodium.

In one aspect of the disclosure, the lubricating oil composition comprises about 0.01 _to about _2.0 wt %, e.g., about 0.1 to about 1.0 wt %, about 0.05 to about 0.5 wt %, and about 0.1 to about 0.5 wt %, in terms of Ca content, of alkyl hydroxybenzoate derived from C10-C40 isomerized NAO.

In one aspect of the disclosure, the lubricating oil composition comprises from about _0.01 to about _2.0 wt %, e.g., from about 0.1 to about 1.0 wt %, from about 0.05 to about 0.5 wt %, and from about 0.1 to about 0.5 wt %, in terms of Mg content, of alkyl hydroxybenzoate derived from C10-C40 isomerized NAO.

In one aspect of the disclosure, the lubricating oil composition comprising the C ₁₀ -C ₄₀ isomerized NAO-derived alkyl hydroxybenzoate detergent is an automobile engine oil composition, a gas engine oil composition, a dual fuel engine oil composition, a mobile gas engine oil composition, or a locomotive engine oil composition.

In one aspect of the present disclosure, lubricating oil compositions containing C ₁₀ -C ₄₀ isomerized NAO-derived alkyl hydroxybenzoate detergents are functional fluids for automotive and industrial applications, such as transmission oils, hydraulic oils, tractor fluids, gear oils, and the like.

In one aspect of the disclosure, the lubricating oil composition comprising the C ₁₀ -C ₄₀ isomerized NAO-derived alkyl hydroxybenzoate detergent is a multigrade oil or a monograde oil.

In one aspect of the disclosure, a lubricating oil composition comprising a C ₁₀ -C ₄₀ isomerized NAO-derived alkyl hydroxybenzoate detergent lubricates crankcases, gears, and clutches.

Ashless sulfur compounds

Sulfurized fatty esters

In one embodiment, the ashless sulfur compound is a sulfurized fatty ester. The sulfurized fatty acid ester is prepared by reacting sulfur, sulfur monochloride, and/or sulfur dichloride with an unsaturated fatty ester at elevated temperatures. Typical esters include C1-C20 alkyl esters of C8-C24 unsaturated fatty acids, such as palmitoleic acid, oleic acid, ricinoleic acid, petroselinic acid, vaccenic acid, linoleic acid, linolenic acid, oleostearic acid, licanic acid, _parinaric acid, thallylic acid, gadoleic acid, _arachidonic acid, _and cetolic acid. Particularly good results have been obtained with _mixed unsaturated fatty acid esters, such as those obtained from animal fats and vegetable oils, such as tall oil, linseed oil, olive oil, castor oil, peanut oil, rapeseed oil, fish oil, and sperm whale oil.

Exemplary fatty esters include lauryl tallate, methyl oleate, ethyl oleate, lauryl oleate, cetyl oleate, cetyl linoleate, lauryl ricinoleate, oleyl linoleate, oleyl stearate, and alkyl glycerides.

Sulfurized olefin

In one embodiment, the ashless sulfur compound is a sulfurized olefin. Cross-sulfurized ester olefins, such as sulfurized mixtures of C10-C25 olefins with fatty acid esters of C10-C25 fatty acids and C10-C25 alkyl or alkenyl alcohols, where the fatty acids and/or alcohols are unsaturated, can also be used. Sulfurized olefins are typically derived from alpha olefins, isomerized alpha olefins, cyclic olefins, branched olefins, and polymeric olefins reacted with a sulfur source. Specific examples of olefins include, but are not limited to, 1-butene, isobutylene, diisobutylene, 1-pentene, 1-hexene, 1-heptene, 1-octene, and those with longer carbon chains up to C60 and polymeric olefins. Other examples of non-normal alpha olefins (NAO) include cyclohexene, cyclooctene, amylene, isoamylene, and branched and internal olefin isomers of NAO.

Examples of sulfur sources include sulfur, hydrogen sulfide, sodium hydrogen sulfide, sodium sulfide, sulfur chloride, and sulfur dichloride.

Also useful are aromatic and alkyl sulfides, such as dibenzyl sulfide, dixylyl sulfide, dicetyl sulfide, diparaffin wax sulfides and polysulfides, cracked wax-olefin sulfides, and the like. They can be prepared by treating starting materials, such as olefinically unsaturated compounds, with sulfur, sulfur monochloride, and sulfur dichloride. The paraffin wax thiomers described in U.S. Patent No. 2,346,156 are particularly preferred.

Thiadiazole:

In one embodiment, the ashless sulfur compound is a thiadiazole. Thiadiazoles include at least one of 2,5-dimercapto-1,3,4-thiadiazole; 2-mercapto-5-hydrocarbylthio-1,3,4-thiadiazole; 2-mercapto-5-hydrocarbyldithio-1,3,4-thiadiazole; 2,5-bis(hydrocarbylthio) and 2,5-bis(hydrocarbyldithio)-1,3,4-thiadiazole. Preferred compounds are 1,3,4-thiadiazoles, particularly 2-hydrocarbyldithio-5-mercapto-1,3,4-dithiadiazole and 2,5-bis(hydrocarbyldithio)-1,3,4-thiadiazole, many of which are commercially available. Other preferred compounds include thiadiazole-containing non-polycarboxylates containing about 4.0% by weight of 2,5-dimercapto-1,3,4-thiadiazole, which are commercially available from Afton. It is commercially available as Hitec® 4313 from Biochemical (Richmond, Virginia) or Lubrizol® 5955A from Lubrizol Corporation (Wycliffe, Ohio).

Ashless dithiophosphate:

In one aspect, the ashless sulfur compound is an ashless dithiophosphate. A class of ashless dithiophosphates suitable for use herein includes those represented by formula (I):

(wherein R ¹¹ and R ¹² are independently alkyl groups having 3 to 8 carbon atoms.) Suitable ashless dithiophosphates include VANLUBE® 7611M, commercially available from R. T. Vanderbilt Co., Inc.

Another class of suitable ashless dithiophosphates for use herein includes dithiophosphate esters of carboxylic acids, such as IRGALUBE® 63, available from BASF.

Yet another class of suitable ashless dithiophosphates for use herein includes triphenyl phosphorothioates, such as IRGALUBE® TPPT, available commercially from BASF.

Hindered sulfurized phenol:

In one embodiment, the ashless sulfur compound is a sulfurized hindered phenol. Sulfurized hindered phenols suitable for use in the present invention can be prepared by many known methods. Sulfurized hindered phenols are characterized by the type of hindered phenol used in their production and their ultimate sulfur content. Hindered tert-butylphenol is preferred. Sulfurized hindered phenols can be chlorine-free and prepared from chlorine-free sulfur sources, such as elemental sulfur, sodium sulfide, or sodium polysulfide, or they can contain chlorine and prepared from chlorinated sulfur sources, such as sulfur monochloride and sulfur dichloride. Preferred sulfurized hindered phenols include those represented by formula (II):

(wherein R is an alkyl group, _R1 is an alkyl group or hydrogen, one of Z or _Z1 is an —OH group and the other is hydrogen, one of _Z2 or _Z3 is an —OH group and the other is hydrogen, X is in the range of 1 to 6, and y is in the range of 0 to 2).

Suitable chlorine-free sulfurized hindered phenols may be prepared by the method taught in U.S. Patent No. 3,929,654, or as taught in co-pending applications 08/657,141, filed June 3, 1996, and 08/877,533, filed February 19, 1997, by (a) preparing a mixture of (i) at least one chlorine-free hindered phenol, (ii) a chlorine-free sulfur source, and (iii) at least one alkali metal hydroxide promoter in a polar solvent, and (b) reacting components (i), (ii), and (iii) for a sufficient time and at a sufficient temperature to form at least one chlorine-free sulfurized hindered phenol.

Suitable sulfurized hindered phenol products prepared from chlorinated sulfur sources include those taught in U.S. Patent Nos. 3,250,712 and 4,946,610, both of which are incorporated herein by reference.

Examples of sulfurized hindered phenols that can be used in the present invention include 4,4'-thiobis(2,6-di-t-butylphenol), 4,4'-dithiobis(2,6-di-t-butylphenol), 4,4'-thiobis(2-t-butyl-6-methylphenol), 4,4'-dithiobis(2-t-butyl-6-methylphenol), 4,4'-thiobis(2-t-butyl-5-methylphenol), and mixtures thereof.

Preferably, the sulfurized hindered phenol is a substantially liquid product. As used herein, substantially liquid refers to a composition that is primarily liquid. In this regard, aged samples of the sulfurized hindered phenol may form trace amounts of crystals, typically around the sides of the container where the product comes into contact with air and glass container surfaces. As taught in co-pending applications 08/657,141, filed June 3, 1996, and 08/877,533, filed February 19, 1997, the sulfurized hindered phenol is preferably chlorine-free, has low corrosivity, and has a high monosulfide content. It is also preferred that the sulfur content of the sulfurized hindered phenol range from about 4.0% to about 12.0% by weight of the additive concentrate.

Phenothiazine:

In one embodiment, the ashless sulfur compound is a phenothiazine. Phenothiazines useful in the practice of the present invention include alkylated phenothiazine compounds represented by formula (III):

(wherein R ¹ is a linear or branched group having 4 to 24 carbon atoms, for example 4 to 10 carbon atoms, and is an alkyl or alkylaryl group; and R ² , independently of R ¹ , is a linear or branched group having 4 to 24 carbon atoms, for example 4 to 10 carbon atoms, and is an alkyl or alkenyl group, or is a hydrogen atom).

As an example of the above formula (III), R ¹ is a nonyl group, and R ² is a hydrogen atom or a nonyl group.

In one embodiment of the alkylated phenothiazine, R ¹ is preferably an alkyl group having from 4 to 10 carbon atoms, and R ² is a hydrogen atom or an alkyl group having from 4 to 10 carbon atoms.

The alkylated phenothiazine preferably comprises a mixture of mono- and di-alkylated phenothiazines, for example, about 15 to about 85% by weight of the mixture being mono-alkylated.

Alkylated phenothiazines are known in the art and can be prepared by methods known in the art. For example, phenothiazine can be alkylated by reaction with suitable such olefins, including _C1 to _C10 olefins or mixtures thereof, alpha olefins and internal olefins, such as isobutylene, diisobutylene, nonene, and 1-decene, in the presence of an acid catalyst.

Additional Detergents The lubricating oil compositions of the present invention may further contain one or more overbased detergents having a TBN of from about 10 to about 800, e.g., from about 10 to about 700, from about 30 to about 690, from about 100 to about 600, from about 150 to about 600, from about 150 to about 500, and from about 200 to about 450 mg KOH/g on an actives basis.

Detergents that can be used include oil-soluble overbased sulfonates, non-sulfur-containing phenates, sulfurized phenates, salixarates, salicylates, saligenins, complex detergents, and naphthenate detergents, as well as other oil-soluble alkylhydroxybenzoates of metals, particularly alkali or alkaline earth metals such as barium, sodium, potassium, lithium, calcium, and magnesium. The most commonly used metals are calcium and magnesium (both of which may be present in detergents used in lubricants), and mixtures of calcium and/or magnesium with sodium.

Overbased metal detergents are typically produced by carbonating a mixture of a hydrocarbon, a detergent acid (e.g., sulfonic acid, alkylhydroxybenzoate, etc.), a metal oxide or hydroxide (e.g., calcium oxide or calcium hydroxide), and a promoter, such as xylene, methanol, and water. For example, to prepare overbased calcium sulfonate, in the carbonation step, calcium oxide or hydroxide reacts with gaseous carbon dioxide to form calcium carbonate. The sulfonic acid is neutralized with CaO or Ca(OH) ₂ to form the sulfonate.

The overbased detergent may be low overbased (e.g., an overbased salt having a TBN of less than about 100 on an actives basis). In one embodiment, the TBN of the low overbased salt may be from about 30 to about 100. In another embodiment, the TBN of the low overbased salt may be from about 30 to about 80.

In some embodiments, the overbased detergent may be medium overbased (e.g., an overbased salt having a TBN of about 100 to about 250). In one embodiment, the TBN of the medium overbased salt may be about 100 to about 200. In another embodiment, the TBN of the medium overbased salt may be about 125 to about 175.

In some embodiments, the overbased detergent may be highly overbased (e.g., an overbased salt having a TBN greater than about 250). In one embodiment, the TBN of the high overbased salt may be from about 250 to about 800 on an actives basis.

In one embodiment, the detergent may be one or more alkali or alkaline earth metal salts of alkyl-substituted hydroxyaromatic carboxylic acids. Suitable hydroxyaromatic compounds include mononuclear monohydroxy and polyhydroxyaromatic hydrocarbons having 1 to 4, preferably 1 to 3, hydroxyl groups. Suitable hydroxyaromatic compounds include phenol, catechol, resorcinol, hydroquinone, pyrogallol, cresol, and the like. A preferred hydroxyaromatic compound is phenol.

The alkyl-substituted moiety of the alkali or alkaline earth metal salt of an alkyl-substituted hydroxyaromatic carboxylic acid is derived from an alpha-olefin having from about 10 to about 80 carbon atoms. The olefins used can be linear, isomerized linear, branched, or partially branched linear. The olefins can be a mixture of linear olefins, a mixture of isomerized linear olefins, a mixture of branched olefins, a partially branched linear mixture, or a mixture of any of the foregoing.

In one embodiment, the mixture of linear olefins that may be used is a mixture of normal alpha olefins selected from olefins having from about 10 to about 40 carbon atoms per molecule. In one embodiment, the normal alpha olefins are isomerized using at least one of a solid catalyst or a liquid catalyst.

In one embodiment, at least about 50 mol%, at least about 75 mol%, at least about 80 mol%, at least about 85 mol%, at least about 90 mol%, or at least about 95 mol% of the alkyl groups in the alkali or alkaline earth metal salt of an alkyl-substituted hydroxyaromatic carboxylic acid, such as the alkyl groups in the alkaline earth metal salt of an alkyl-substituted hydroxybenzoic acid detergent, are _C20 or _greater . In another embodiment, the alkali or alkaline earth metal salt of an alkyl-substituted hydroxyaromatic carboxylic acid is an alkali or alkaline earth metal salt of an alkyl-substituted hydroxybenzoic acid derived from an alkyl-substituted hydroxybenzoic acid in which the alkyl group is _{a C20} to about C28 normal alpha-olefin. The alkyl group on at least one of the at least two alkylphenols is derived from an isomerized alpha-olefin. The alkyl group on the second alkylphenol may be derived from a branched or partially branched olefin, a highly isomerized olefin, or a mixture thereof.

In another embodiment, the alkali or alkaline earth metal salt of an alkyl-substituted hydroxyaromatic carboxylic acid is a salicylate derived from an isomerized NAO having an alkyl group having from about 20 to about 40 carbon atoms, preferably from about 20 to about 28 carbon atoms, and more preferably from about 20 to about 40 carbon atoms.

Sulfonates can be prepared from sulfonic acids typically obtained by sulfonation of alkyl-substituted aromatic hydrocarbons, such as those obtained from petroleum fractionation or by alkylation of aromatic hydrocarbons. Examples include those obtained by alkylating benzene, toluene, xylene, naphthalene, diphenyl, or their halogen derivatives. The alkyl group of the alkaryl sulfonate typically contains from about 9 to about 80 or more carbon atoms, preferably from about 16 to about 60 carbon atoms, preferably from about 16 to about 30 carbon atoms, and more preferably from about 20 to about 24 carbon atoms.

Sulfurized phenate detergents, metal salts of phenols and sulfurized phenols, are prepared by reaction with an appropriate metal compound, such as an oxide or hydroxide. Neutral or overbased detergent products can be obtained by methods well known in the art. Sulfurized phenols can be prepared by reacting phenol with sulfur or a sulfur-containing compound, such as hydrogen sulfide, a sulfur monohalide, or a sulfur dihalide, to form a product that is usually a mixture of compounds in which two or more phenols are bridged by a sulfur-containing bridge.

Further details regarding the general preparation of sulfurized phenates can be found, for example, in U.S. Patent Nos. 2,680,096; 3,178,368; 3,801,507; and 8,580,717, the contents of which are incorporated herein by reference.

The reactants and reagents used in this process may utilize all allotropes of sulfur. The sulfur may be used either as molten sulfur, as a solid (e.g., powder or particles), or as a solid suspension in a compatible hydrocarbon liquid.

In certain circumstances, it may be desirable to use calcium hydroxide as the calcium base due to its superior performance. Calcium hydroxide is considered easier to handle than, for example, calcium oxide. Other suitable calcium bases include, for example, calcium alkoxides.

Suitable alkyl phenols that can be used are those in which the alkyl substituent contains a sufficient number of carbon atoms so that the resulting overbased sulfurized calcium alkylphenate composition is oil-soluble. Oil-solubility can be provided by a single long-chain alkyl substituent or by a combination of alkyl substituents. Typically, the alkyl phenol used is a mixture of different alkyl phenols, e.g., _C20 - _C24 alkyl phenols.

In one embodiment, suitable alkyl phenolic compounds are derived from isomerized alpha-olefin alkyl groups having from about 10 to about 40 carbon atoms per molecule and having an alpha-olefin isomerization level (l) of from about 0.1 to about 0.4. In one embodiment, suitable alkyl phenolic compounds are derived from alkyl groups that are branched olefinic propylene oligomers or mixtures thereof having from about 9 to about 80 carbon atoms. In one embodiment, the branched olefinic propylene oligomers or mixtures thereof have from about 9 to about 40 carbon atoms. In one embodiment, the branched olefinic propylene oligomers or mixtures thereof have from about 9 to about 18 carbon atoms. In one embodiment, the branched olefinic propylene oligomers or mixtures thereof have from about 9 to about 12 carbon atoms.

In one embodiment, suitable alkylphenolic compounds can be sourced from distilled cashew nut shell liquid (CNSL) or hydrogenated distilled cashew nut shell liquid. Distilled CNSL is a mixture of biodegradable meta-hydrocarbyl-substituted phenols in which the hydrocarbyl groups are linear and unsaturated, including cardanol. Catalytic hydrogenation of distilled CNSL yields a mixture of meta-hydrocarbyl-substituted phenols primarily enriched in 3-pentadecylphenol.

The alkylphenol may be para-, meta-, or ortho-alkylphenol. Because para-alkylphenols are believed to facilitate the preparation of highly overbased calcium sulfurized alkylphenates where an overbased product is desired, the alkylphenol is preferably predominantly para-alkylphenol, with no more than about 45 mole percent of the alkylphenols being ortho-alkylphenol; more preferably, no more than about 35 mole percent of the alkylphenols being ortho-alkylphenol. Alkyl-hydroxytoluenes or xylenes and other alkylphenols having one or more alkyl substituents in addition to at least one long-chain alkyl substituent may also be used. In the case of distilled cashew nut shell liquid, catalytic hydrogenation of the distilled CNSL results in a mixture of meta-hydrocarbyl-substituted phenols.

In one embodiment, one or more overbased detergents may be a complex or hybrid detergent, known in the art as comprising a surfactant system derived from at least two of the surfactants described above.

In one embodiment, the one or more overbased detergents may be salicylates having alkyl groups having from about 20 to about 28 carbon atoms, more preferably from about 20 to about 24 carbon atoms. In another embodiment, the one or more overbased detergents are salicylates having alkyl groups derived from C _14-18 NAO and may provide less than 0.05 wt %, preferably less than 0.025 wt %, more preferably less than 0.01 wt %, in terms of Ca content, to the lubricating oil.

Typically, the amount of detergent can be from about 0.001 to about 50 weight percent, or from about 0.05 to about 25 weight percent, or from about 0.1 to about 20 weight percent, or from about 0.01 to 15 weight percent, based on the total weight of the lubricating oil composition.

Antiwear Agents The lubricating oil compositions disclosed herein may contain one or more antiwear agents. Antiwear agents reduce wear of metal parts. Suitable antiwear agents include dihydrocarbyl dithiophosphate metal salts, such as zinc dihydrocarbyl dithiophosphate (ZDDP) of formula (IV):
Zn[SP(=S)(OR ¹ )(OR ² )] ₂ Formula (IV)
(wherein R ¹ and R ² can be the same or different hydrocarbyl groups having 1 to 18 (e.g., 2 to 12) carbon atoms. Suitable hydrocarbyl groups include, but are not limited to, alkyl, alkenyl, aryl, arylalkyl, alkaryl, and alicyclic groups. Particularly preferred R ¹ and R ² groups include alkyl groups having 2 to 8 carbon atoms (e.g., ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, n-pentyl, isopentyl, n-hexyl, isohexyl, 2-ethylhexyl). To obtain oil solubility, the total number of carbon atoms (i.e., R ¹ +R ² ) should be at least 5. Thus, the zinc dihydrocarbyl dithiophosphate can include a zinc dialkyldithiophosphate. The zinc dialkyldithiophosphate can be a primary or secondary zinc dialkyldithiophosphate, or a combination thereof. ZDDP may be present at up to about 3 weight percent (e.g., from about 0.1 to about 1.5 weight percent, or from about 0.5 to about 1.0 weight percent) of the lubricating oil composition. In one embodiment, the lubricating oil composition containing the magnesium salicylate detergent described herein further comprises an antioxidant compound. In one embodiment, the antioxidant is a diphenylamine antioxidant. In another embodiment, the antioxidant is a hindered phenol antioxidant. In yet another embodiment, the antioxidant is a combination of a diphenylamine antioxidant and a hindered phenol antioxidant.

Antioxidants The lubricating oil compositions disclosed herein may contain one or more antioxidants. Antioxidants reduce the tendency of mineral oils to deteriorate during service. Oxidative deterioration can be manifested by sludge in the lubricant, varnish-like deposits on metal surfaces, and/or viscosity increase. Suitable antioxidants include hindered phenols, aromatic amines, and sulfurized alkylphenols and their alkali and alkaline earth metal salts.

Hindered phenol antioxidants often contain secondary butyl and/or tertiary butyl groups as sterically hindering groups. The phenol group may be further substituted with hydrocarbyl groups (typically linear or branched alkyl) and/or bridging groups linking to a second aromatic group. Examples of suitable hindered phenol antioxidants include 2,6-di-tert-butylphenol; 4-methyl-2,6-di-tert-butylphenol; 4-ethyl-2,6-di-tert-butylphenol; 4-propyl-2,6-di-tert-butylphenol; 4-butyl-2,6-di-tert-butylphenol; and 4-dodecyl-2,6-di-tert-butylphenol. Other useful hindered phenol antioxidants include 2,6-di-alkyl-phenolic propionate derivatives, such as IRGANOX® L-135 from Ciba, and bisphenolic antioxidants, such as 4,4′-bis(2,6-di-tert-butylphenol) and 4,4′-methylenebis(2,6-di-tert-butylphenol).
Typical aromatic amine antioxidants have at least two aromatic groups attached directly to one amine nitrogen. Typical aromatic amine antioxidants have alkyl substituents of at least six carbon atoms. Specific examples of aromatic amine antioxidants useful herein include 4,4'-dioctyldiphenylamine, 4,4'-dinonyldiphenylamine, N-phenyl-1-naphthylamine, N-(4-tert-octyphenyl)-1-naphthylamine, and N-(4-octylphenyl)-1-naphthylamine. The antioxidant may be present at about 0.01 to about 5 weight percent (e.g., about 0.1 to about 2 weight percent) of the lubricating oil composition.

Dispersants The lubricating oil compositions disclosed herein may contain one or more dispersants. Dispersants maintain oil-insoluble substances resulting from oxidation during engine operation in suspension, thereby preventing sludge flocculation and precipitation or deposition on metal parts. Dispersants useful herein include nitrogen-containing ashless (metal-free) dispersants known to be effective in reducing deposit formation when used in gasoline and diesel engines.

Suitable dispersants include hydrocarbyl succinimides, hydrocarbyl succinamides, mixed esters/amides of hydrocarbyl-substituted succinic acid, hydroxy esters of hydrocarbyl-substituted succinic acid, and Mannich condensation products of hydrocarbyl-substituted phenols, formaldehyde, and polyamines. Condensation products of polyamines and hydrocarbyl-substituted phenyl acids are also suitable. Mixtures of these dispersants may also be used. Basic nitrogen-containing ashless dispersants are well-known lubricating oil additives, and their preparation is widely described in the patent literature. Preferred dispersants are alkenyl succinimides and succinamides, in which the alkenyl substituents are long chains, preferably greater than about 40 carbon atoms. These materials are readily produced by reacting hydrocarbyl-substituted dicarboxylic acid materials with molecules containing amine functionality. Examples of suitable amines are polyamines, such as polyalkylene polyamines, hydroxy-substituted polyamines, and polyoxyalkylene polyamines.

A particularly preferred ashless dispersant is polyisobutenyl succinimide formed from polyisobutenyl succinic anhydride and a polyalkylene polyamine, such as a polyethylene polyamine of formula (V):
NH ₂ (CH ₂ CH ₂ NH) _z H Formula (V)
where z is 1 to 11. The polyisobutenyl group is derived from polyisobutene and preferably has an average molecular weight (M _n ) ranging from about 700 to about 3000 daltons (e.g., about 900 to about 2500 daltons). For example, the polyisobutenyl succinimide may be a bis-succinimide derived from a polyisobutenyl group having an M _n of about 900 to about 2500 daltons. As is known in the art, the dispersants may be post-treated (e.g., with boronating agents or cyclic carbonates, ethylene carbonate, etc.).

Nitrogen-containing ashless (metal-free) dispersants are basic and contribute to the TBN of the lubricating oil composition to which they are added without introducing additional sulfated ash. Dispersants may be present at about 0.1 to about 10 weight percent (e.g., about 2 to about 5 weight percent) of the lubricating oil composition.

Foam Inhibitors The lubricating oil compositions disclosed herein may contain one or more foam inhibitors that can destroy gas bubbles in the oil. Non-limiting examples of suitable foam inhibitors or anti-foam inhibitors include silicone oils or polydimethylsiloxanes, fluorosilicones, alkoxylated aliphatic acids, polyethers (e.g., polyethylene glycol), branched polyvinyl ethers, alkyl acrylate polymers, alkyl methacrylate polymers, polyalkoxyamines, and combinations thereof.

Additional Co-additives The lubricating oil compositions of the present disclosure may also contain other conventional additives that can impart or improve any desired properties of the lubricating oil composition, and these additives are dispersed or dissolved in the lubricating oil composition. Any additive known to those skilled in the art may be used in the lubricating oil compositions disclosed herein. Some suitable additives are described in Mortier et al., "Chemistry and Technology of Lubricants", 2nd Edition, London, Springer, (1996); and Leslie R. Rudnick, "Lubricant Additives: Chemistry and Applications", New York, Marcel Dekker (2003), both of which are incorporated herein by reference. For example, the lubricating oil composition may be blended with antioxidants, antiwear agents, detergents such as metal detergents, rust inhibitors, haze removers, demulsifiers, metal deactivators, friction modifiers, pour point depressants, anti-foam agents, co-solvents, corrosion inhibitors, ashless dispersants, multifunctional agents, pigments, extreme pressure agents, and the like, and mixtures thereof. A wide variety of additives are known and commercially available. These additives, or similar compounds thereof, may be used to prepare the lubricating oil compositions of the present disclosure by conventional blending procedures.

In preparing lubricating oil formulations, it is common practice to introduce the additive in the form of a concentrate of about 10 to about 100% by weight of the active ingredient in a hydrocarbon oil, e.g., mineral lubricating oil, or other suitable solvent.

Typically, these concentrates can be diluted with about 3 to about 100, e.g., about 5 to about 40, parts by weight of lubricating oil per part by weight of additive package in forming a finished lubricant, e.g., crankcase motor oil. The purpose of the concentrate, of course, is to reduce the difficulty and messiness of handling the various materials and to facilitate dissolution or dispersion in the final blend.

Each of the foregoing additives, when used, is in a functionally effective amount to impart the desired characteristic to the lubricant. Thus, for example, if an additive is a friction modifier, a functionally effective amount of the friction modifier would be an amount sufficient to impart the desired friction modifying characteristic to the lubricant.

Typically, the concentration of each of the additives in the lubricating oil composition, if used, can range from about 0.001 wt % to about 20 wt %, about 0.01 wt % to about 15 wt %, or about 0.1 wt % to about 10 wt %, about 0.005 wt % to about 5 wt %, or about 0.1 wt % to about 2.5 wt %, based on the total weight of the lubricating oil composition. Furthermore, the total amount of additives in the lubricating oil composition can range from about 0.001 wt % to about 20 wt %, about 0.01 wt % to about 10 wt %, or about 0.1 wt % to about 5 wt %, based on the total weight of the lubricating oil composition.

Oil of lubricating viscosity (sometimes called a "base stock" or "base oil") is the primary liquid component of a lubricant into which additives and optionally other oils are blended, for example, to produce the finished lubricant (or lubricant composition). Base oils are useful for producing concentrates and lubricating oil compositions derived therefrom, and may be selected from natural and synthetic lubricating oils and combinations thereof.

Natural oils include animal and vegetable oils, liquid petroleum oils, and hydrorefined and solvent-treated mineral lubricating oils of the paraffinic, naphthenic, and mixed paraffinic-naphthenic types. Oils of lubricating viscosity derived from coal or shale are also useful base oils.

Synthetic lubricating oils include hydrocarbon oils such as polymerized and copolymerized olefins (e.g., polybutylene, polypropylene, propylene-isobutylene copolymers, chlorinated polybutylene, poly(1-hexene), poly(1-octene), poly(1-decene); alkylbenzenes (e.g., dodecylbenzene, tetradecylbenzene, dinonylbenzene, di(2-ethylhexyl)benzene); polyphenols (e.g., biphenyls, terphenyls, alkylated polyphenols); and alkylated diphenyl ethers and alkylated diphenyl sulfides, as well as their derivatives, analogs, and homologs.

Another suitable class of synthetic lubricating oils comprises the esters of dicarboxylic acids (e.g., malonic acid, alkylmalonic acid, alkenylmalonic acid, succinic acid, alkylsuccinic acid and alkenylsuccinic acid, maleic acid, fumaric acid, azelaic acid, suberic acid, sebacic acid, adipic acid, linoleic acid dimer, phthalic acid) with various alcohols (e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether, propylene glycol). Specific examples of these esters include dibutyl adipate, di(2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, 2-ethylhexyl diester of linoleic acid dimer, and a complex ester formed by reacting 1 mole of sebacic acid with 2 moles of tetraethylene glycol and 2 moles of 2-ethylhexanoic acid.

Esters useful as synthetic oils also include those made from C ₅ to C ₁₂ monocarboxylic acids and polyols and polyol ethers, such as neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, and tripentaerythritol.

Base oils can be derived from Fischer-Tropsch synthesized hydrocarbons. Fischer-Tropsch synthesized hydrocarbons are produced from synthesis gas containing _H2 and CO using a Fischer-Tropsch catalyst. Such hydrocarbons typically require further processing to be useful as base oils. For example, the hydrocarbons can be hydroisomerized; hydrocracking and hydroisomerized; dewaxed; or hydroisomerized and dewaxed using processes known to those skilled in the art.

Unrefined, refined, and re-refined oils can be used in the lubricating oil compositions. Unrefined oils are those obtained directly from natural or synthetic sources without further purification treatment. For example, shale oil obtained directly from a retort operation, petroleum oil obtained directly from distillation, or ester oil obtained directly from an esterification process and used without further treatment would be unrefined oils. Refined oils are similar to unrefined oils except that they have been further treated in one or more purification steps to improve one or more properties. Many such purification techniques, such as distillation, solvent extraction, acid or base extraction, filtration, and percolation, are known to those skilled in the art.

Re-refined oils are obtained by processes similar to those used to obtain refined oils applied to refined oils already in service. Such re-refined oils are also known as reclaimed or reprocessed oils and are often further processed by techniques for the approval of used additives and oil breakdown products.

Thus, the base oils that may be used to produce the present lubricating oil compositions may be selected from any of the base oils in Groups I to V as defined in the American Petroleum Institute (API) Base Oil Interchangeability Guidelines (API Publication 1509). Such base oil groups are summarized in Table 1 below:

Suitable base oils for use herein are any of the types corresponding to API Group II, Group III, Group IV, and Group V oils and combinations thereof, preferably Group III-V oils (due to their exceptional volatility, stability, viscosity, and cleanliness characteristics).

The oil of lubricating viscosity for use in the lubricating oil compositions of this disclosure, also referred to as the base oil, is typically present in a major amount, e.g., greater than about 50 wt %, preferably greater than about 70 wt %, more preferably about 80 to about 99.5 wt %, and most preferably about 85 to about 98 wt %, based on the total weight of the composition. The expression "base oil," as used herein, should be understood to mean a base stock or blend of base stocks that is a lubricant component produced to the same specifications by a single manufacturer (regardless of source or location of manufacturer); meets the same manufacturer's specifications; and is identified by a unique formulation, product identification number, or both. A base oil for use herein can be any now-known or later-discovered oil of lubricating viscosity used in formulating lubricating oil compositions for any and all applications, e.g., engine oils, marine cylinder oils, functional fluids, e.g., hydraulic oils, gear oils, transmission fluids, etc. The base oils for use herein may also optionally contain viscosity index improvers, such as polymeric alkyl methacrylates; olefin copolymers, such as ethylene-propylene copolymers or styrene-butadiene copolymers, and mixtures thereof.

As one skilled in the art would readily understand, the viscosity of the base oil will depend on the application. Accordingly, the viscosity of base oils for use herein typically ranges from about 2 to about 2000 centistokes (cSt) at 100° Celsius (C.). Typically, individual base oils used as engine oils have a kinematic viscosity range at 100° C. of about 2 cSt to about 30 cSt, preferably about 3 cSt to about 16 cSt, and most preferably about 4 cSt to about 12 cSt, and are selected and blended depending on the desired end use and additives in the finished oil to produce the desired grade of engine oil, e.g., 0W, 0W-8, 0W-12, 0W-16, 0W-20, 0W-22, 0W-24, 0W-26, 0W-28, 0W-29, 0W-30, 0W-31, 0W-32, 0W-33, 0W-34, 0W-35, 0W-36, 0W-37, 0W-38, 0W-39, 0W-39, 0W-40, 0W-41, 0W-42, 0W-43, 0W-44, 0W-45, 0W-46, 0W-47, 0W-48, 0W-49 ...9, 0W-49, 0W-49, 0W-49, 0W-49, 0W-49, 0W-49, 0W-49, 0W-49, Lubricating oil compositions with SAE viscosity grades such as W-16, 0W-20, 0W-26, 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, 30, and 40 can be obtained.

Lubricating Oil Compositions Typically, the level of sulfur in the lubricating oil compositions of the present invention is about 0.7 wt % or less, e.g., about 0.01 wt % to about 0.70 wt %, about 0.01 to about 0.6 wt %, about 0.01 to about 0.5 wt %, about 0.01 to about 0.4 wt %, about 0.01 to about 0.3 wt %, about 0.01 to about 0.2 wt %, or about 0.01 to about 0.10 wt % sulfur, based on the total weight of the lubricating oil composition. In one embodiment, the level of sulfur in the lubricating oil compositions of the present invention is about 0.60 wt % or less, about 0.50 wt % or less, about 0.40 wt % or less, about 0.30 wt % or less, about 0.20 wt % or less, or about 0.10 wt % or less, based on the total weight of the lubricating oil composition.

In one embodiment, the level of phosphorus in the lubricating oil composition of the present invention is about 0.12 wt % or less, e.g., from about 0.01 wt % to about 0.12 wt % of phosphorus, based on the total weight of the lubricating oil composition. In one embodiment, the level of phosphorus in the lubricating oil composition of the present invention is about 0.11 wt % or less, e.g., from about 0.01 wt % to about 0.11 wt % of phosphorus, based on the total weight of the lubricating oil composition. In one embodiment, the level of phosphorus in the lubricating oil composition of the present invention is about 0.10 wt % or less, e.g., from about 0.01 wt % to about 0.10 wt % of phosphorus, based on the total weight of the lubricating oil composition. In one embodiment, the level of phosphorus in the lubricating oil composition of the present invention is about 0.09 wt % or less, e.g., from about 0.01 wt % to about 0.09 wt % of phosphorus, based on the total weight of the lubricating oil composition. In one embodiment, the level of phosphorus in the lubricating oil composition of the present invention is about 0.08 wt. % or less, e.g., from about 0.01 wt. % to about 0.08 wt. % based on the total weight of the lubricating oil composition. In one embodiment, the level of phosphorus in the lubricating oil composition of the present invention is about 0.07 wt. % or less, e.g., from about 0.01 wt. % to about 0.07 wt. % based on the total weight of the lubricating oil composition. In one embodiment, the level of phosphorus in the lubricating oil composition of the present invention is about 0.05 wt. % or less, e.g., from about 0.01 wt. % to about 0.05 wt. % based on the total weight of the lubricating oil composition.

In one embodiment, the lubricating oil compositions of the present invention produce sulfated ash levels of about 1.60 wt % or less, as determined by ASTM D 874, e.g., about 0.10 to about 1.60 wt % sulfated ash, as determined by ASTM D 874. In one embodiment, the lubricating oil compositions of the present invention produce sulfated ash levels of about 1.00 wt % or less, as determined by ASTM D 874, e.g., about 0.10 to about 1.00 wt % sulfated ash, as determined by ASTM D 874. In one embodiment, the lubricating oil compositions of the present invention produce sulfated ash levels of about 0.80 wt % or less, as determined by ASTM D 874, e.g., about 0.10 to about 0.80 wt % sulfated ash, as determined by ASTM D 874. In one embodiment, the sulfated ash level produced by the lubricating oil composition of the present invention is about 0.60 wt. % or less as determined by ASTM D 874, e.g., about 0.10 to about 0.60 wt. % sulfated ash as determined by ASTM D 874.

In certain embodiments, the present disclosure provides lubricating oil compositions suitable for reducing friction in passenger vehicle internal combustion engines, particularly spark ignition, direct injection, and/or port fuel injected engines. In certain embodiments, the engine may be coupled to an electric motor/battery system in a hybrid vehicle (e.g., a port fuel injected spark ignition engine coupled to an electric motor/battery system in a hybrid vehicle). In certain embodiments, the present disclosure provides lubricating oil compositions suitable for reducing friction in heavy-duty diesel internal combustion engines.

The following examples are provided to illustrate embodiments of the present invention and are not intended to limit the invention to the specific embodiments shown. Unless indicated to the contrary, all parts and percentages are by weight. All numerical values are approximate. When numerical ranges are given, it should be understood that embodiments outside the stated ranges may still fall within the scope of the invention. Specific details recited in each example should not be construed as necessary features of the invention.

The following examples are intended for illustrative purposes only and are not intended to limit the scope of the present disclosure in any way.

Isomerization Level (I) and NMR Methods The isomerization level (I) of olefins was determined by hydrogen-1 (1H) NMR. NMR spectra were obtained on a Bruker Ultrashield Plus 400 at 400 MHz using TopSpin 3.2 spectrum processing software. NMR samples were dissolved in chloroform-d1.

The isomerization level (I) represents the relative amount of methyl groups (-CH3) (chemical shift 0.3-1.01 ppm) attached to methylene backbone groups (-CH2-) (chemical shift 1.01-1.38 ppm), and is defined by equation (1) shown below:
I=m/(m+n) Equation (I)
where m is the NMR integral for methyl groups with chemical shifts between 0.3±0.03 and 1.01±0.03 ppm, and n is the NMR integral for methylene groups with chemical shifts between 1.01±0.03 and 1.38±0.10 ppm.

The isomerization level (I) of the alpha olefin is between about 0.1 and about 0.4, preferably between about 0.1 and about 0.3, and more preferably between about 0.12 and about 0.3.

In one embodiment, the NAO has an isomerization level of about 0.16 and has about 20 to about 24 carbon atoms.

In another embodiment, the NAO has an isomerization level of about 0.26 and has about 20 to about 24 carbon atoms.

Example A
Alkylated phenols and Ca alkylhydroxybenzoates were prepared in substantially the same manner as in U.S. Patent No. 8,993,499 using C _20-24 isomerized normal alpha olefins. The isomerization level of the alpha olefins is about 0.16. The resulting alkylhydroxybenzoate composition has a TBN of about 225 on an oil-free basis and a Ca content of about 8 wt.%.

Comparative example B
The alkyl hydroxybenzoate was prepared from an alkylphenol having an alkyl group derived from C _14-18 NAO, a TBN of about 300 on an oil-free basis and a Ca content of about 10.6 wt. %.

Example C
Example C is a sulfurized olefin, namely sulfurized isobutylene.

Example D
Example D is a sulfurized fatty ester which is (9-octadecenoic acid (Z)-, isooctyl ester, reaction product of glycerol trioleate and sulfur).

Example E
Example E is an ashless dithiocarbamate, namely methylenebis(dibutyldithiocarbamate).

Example F
Example F is a thiadiazole having the trade name Hitec 4313.

Example G
Example G is an ashless dithiophosphate having the trade name Irgalube TPPT.

Example H
Example H is a sulfurized phenol having a sulfur content of 15.8 wt.%.

Baseline Formulation 1
A 15W-40 lubricating oil composition was prepared containing a major amount of a Group II base oil of lubricating viscosity and the following additives:
(1) a mixture of three dispersants; (2) a secondary zinc dialkyldithiophosphate in an amount of 0.077% by weight of phosphorus;
(3) olefin copolymer viscosity index improvers;
(4) polymethacrylate pour point depressants; and (5) foam inhibitors.

Example 1
Between 30-36 mM of Example A was added to Baseline 1, providing between 1200-1400 ppm Ca to the lubricant. Also added was 0.29 wt % of Example C, providing approximately 1300 ppm sulfur to the finished oil.

Example 2
Between 30-36 mM of Example A was added to Baseline 1, providing between 1200-1400 ppm Ca to the lubricant. Also added was 1.35 wt % of Example D, providing approximately 1300 ppm sulfur to the finished oil.

Example 3
Between 30-36 mM of Example A was added to Baseline 1, providing between 1200-1400 ppm Ca to the lubricant. Also added was 0.375 wt % of Example F, providing approximately 1300 ppm sulfur to the finished oil.

Example 4
Between 30-36 mM of Example A was added to Baseline 1, providing between 1200-1400 ppm Ca to the lubricant. Also added was 1.452 wt % of Example G, providing approximately 1300 ppm sulfur to the finished oil.

Example 5
Between 30-36 mM of Example A was added to Baseline 1, providing between 1200-1400 ppm Ca to the lubricant. Also added was 0.854 wt % of Example H, providing approximately 1300 ppm sulfur to the finished oil.

Comparative Example 1
Between 30-36 mM of Comparative Example B was added to Baseline 1, providing between 1200-1400 ppm of Ca to the lubricant. Also added was 0.29 wt % of Example C, providing approximately 1300 ppm of sulfur to the finished oil.

Comparative Example 2
Between 30-36 mM of Comparative Example B, which provides between 1200-1400 ppm of Ca to the lubricant, was added to Baseline 1. Also added was 1.35 wt % of Example D, which provides approximately 1300 ppm of sulfur to the finished oil.

Comparative Example 3
Between 30-36 mM of Example A was added to Baseline 1, providing between 1200-1400 ppm Ca to the lubricant. Also added was 0.45 wt % of Example E, providing approximately 1300 ppm sulfur to the finished oil.

Comparative Example 4
Between 30-36 mM of Comparative Example B, which provides between 1200-1400 ppm of Ca to the lubricant, was added to Baseline 1. Also added was 0.45 wt % of Example E, which provides approximately 1300 ppm of sulfur to the finished oil.

Example I
Example I was prepared by slurrying MgO (82 grams) in MeOH (81.4 grams), and xylene (500 grams) was prepared and introduced into a reactor. Hydroxybenzoic acid (1774 grams, 43% active material in xylene) produced from isomerized alpha olefins (C20-24, isomerization level 0.16) was then added to the reactor, and the temperature was maintained at 40°C for 15 minutes. Dodecenyl anhydride (DDSA, 7.6 grams) was then introduced into the reactor, followed by AcOH (37.3 grams), and then _H2O (69 grams) over 30 minutes, while the temperature was increased to a maximum of 50°C. _CO2 was then introduced into the reactor (96 grams) under vigorous agitation. A slurry consisting of MgO (28 grams) in xylene (200 grams) was then introduced into the reactor, and an additional amount of _CO2 was bubbled through the mixture. At the end of _CO2 introduction, distillation of the solvent is achieved by heating to 132°C. 500 grams of base oil are then introduced into the reactor. The mixture is then centrifuged in a laboratory centrifuge to remove unreacted magnesium oxide and other solids. Finally, the mixture is heated at 170°C under vacuum (15 mbar) to remove the xylene, resulting in a final product containing 4.3% magnesium as a _C20 - _C24 magnesium alkylhydroxybenzoate detergent produced from isomerized NAO with an isomerization level of 0.16. Properties: TBN (mg KOH/g) = 199 in 35 wt% diluent oil.

Comparative example J
Comparative Example J is a C ₁₄ -C ₁₈ magnesium alkyl hydroxybenzoate detergent made from an alpha olefin. Properties: TBN (mg KOH/g) = 236; Mg (wt %) = 5.34.

Comparative Example 5
Between 38-46 mM of Example I was added to Baseline 1, providing between 900-1200 ppm Mg to the lubricant. Also added was 0.45 wt % of Example E, providing approximately 1300 ppm sulfur to the finished oil.

Comparative Example 6
Between 38 and 46 mM of Comparative Example J, which provides between 900 and 1100 ppm Mg to the lubricant, was added to Baseline 1. Also added was 0.45 wt % of Example E, which provides approximately 1300 ppm sulfur to the finished oil.

Comparative Example 7
Between 30-36 mM of Comparative Example B, which provides between 1200-1400 ppm of Ca to the lubricant, was added to Baseline 1. Also added was 0.375 wt % of Example F, which provides approximately 1300 ppm of sulfur to the finished oil.

Comparative Example 8
Between 30-36 mM of Comparative Example B, which provides between 1200-1400 ppm of Ca to the lubricant, was added to Baseline 1. Also added was 1.452 wt % of Example G, which provides approximately 1300 ppm of sulfur to the finished oil.

Comparative Example 9
Between 30-36 mM of Comparative Example B, which provides between 1200-1400 ppm of Ca to the lubricant, was added to Baseline 1. Also added was 0.854 wt % of Example H, which provides approximately 1300 ppm of sulfur to the finished oil.

Example K
Alkylated phenols and Ca alkyl hydroxybenzoates were prepared in substantially the same manner as in U.S. Patent No. 8,993,499 using C _20-24 isomerized normal alpha olefins. The isomerization level of the alpha olefins is about 0.15. The resulting alkyl hydroxybenzoate composition has a TBN of about 225 on an oil-free basis and a Ca content of about 8 wt.%.

Example L
Alkylated phenols and Ca alkyl hydroxybenzoates were prepared in substantially the same manner as in U.S. Patent No. 8,993,499 using C _20-24 isomerized normal alpha olefins. The isomerization level of the alpha olefins is about 0.219. The resulting alkyl hydroxybenzoate composition has a TBN of about 225 on an oil-free basis and a Ca content of about 8 wt.%.

Example M
Alkylated phenols and Ca alkylhydroxybenzoates were prepared in substantially the same manner as in U.S. Patent No. 8,993,499 using C _20-24 isomerized normal alpha olefins. The isomerization level of the alpha olefins is about 0.23. The resulting alkylhydroxybenzoate composition has a TBN of about 225 on an oil-free basis and a Ca content of about 8 wt.%.

Example 6
Between 30-36 mM of Example K was added to Baseline 1, providing between 1200-1400 ppm of Ca to the lubricant. Also added was 0.29 wt % of Example C, providing approximately 1300 ppm of sulfur to the finished oil.

Example 7
Between 30-36 mM of Example L was added to Baseline 1, providing between 1200-1400 ppm Ca to the lubricant. Also added was 0.29 wt % of Example C, providing approximately 1300 ppm sulfur to the finished oil.

Example 8
Between 30-36 mM of Example M, which provides between 1200-1400 ppm Ca to the lubricant, was added to Baseline 1. Also added was 0.29 wt % of Example C, which provides approximately 1300 ppm sulfur to the finished oil.

Oxidation-Nitration Test The oxidation-nitration bench test demonstrates the ability of a lubricating oil to resist oxidation and nitration. This test is an additional tool to assist in determining an oil's performance as it relates to actual service lubricating engines using natural gas as a fuel source. The lower the values for oxidation and nitration at the end of the test, the better the product's performance. The oxidation-nitration bench test was designed to simulate the Caterpillar 3500 series engine conditions associated with the actual field performance of the Caterpillar 3516 model. The oxidation-nitration test was performed on Examples 1-8 and Comparative Examples 1-9. The lubricating oil compositions from these examples were placed in a heated glass bath and subjected to calibrated levels of nitrous oxide gas for a specified period of time. The test was run in duplicate for each sample, and the results are the average of the two runs. The samples were evaluated using differential infrared spectroscopy before placing them in a heated glass bath to determine a baseline for each sample. The samples were re-evaluated at the end of the test period. The difference between the baseline data, the absorbance units at 5.8 and 6.1 microns, and the data obtained at the end of the test cycle provides an indication of the oxidation-nitration resistance of the sample.

Differential infrared spectroscopy measures the amount of light absorbed by an oil sample, providing a unit of measurement called absorbance units. DIR (differential infrared) spectra were determined by subtracting the fresh oil spectrum from the used oil spectrum to observe changes caused by oxidation, nitration, fuel dilution, soot buildup, and/or contamination. A 0.1 millimeter (mm) cell is typically used; however, an ATR crystal setup can be used after determining its associated pathlength. If the instrument does not have software to determine the pathlength, the pathlength can be back-calculated by measuring oxidation with a calibrated 0.1 mm cell. Variation between ATR and vertical cell measurements is minimal when limited to the narrow region of oxidation and nitration (approximately 1725 to 1630 cm ^-1 ).

DIR oxidation was measured (in absorbance units) from the peak maximum at approximately 1715±5 cm ⁻¹ to the spectral baseline.

DIR nitration was measured (in absorbance units) from the peak maximum at approximately 1630±1 cm ⁻¹ to the peak baseline.

The oxidation level of 5.8 microns and the nitration level of 6.1 microns were used for peak height comparison.

The example containing the ashless sulfur compound and isomerized NAO detergent performed better than its corresponding comparative example containing the same ashless sulfur compound and non-isomerized detergent. This test, which quantifies a lubricant's resistance to oxidation, is used to determine whether it is a good candidate for extending the life of the lubricant. Oxidation is undesirable in lubricants.

Examples 1-8 and Comparative Examples 1-9 were tested separately by using each as a lubricant in bench tests.

The oxidation performance of the samples was analyzed using differential IR as described above.

The table below shows the oxidation performance.

Claims (4)

1. A method of lubricating an automobile engine, a gas engine, a dual fuel engine, a mobile gas engine, or a locomotive engine, said method comprising:
1. The method of claim 1, further comprising lubricating with a lubricating oil composition comprising: (a) a major amount of oil of lubricating viscosity; and (b) one or more detergents comprising at least one alkyl hydroxybenzoate compound derived from isomerized normal alpha olefins (NAO) having 10 to 40 carbon atoms; and (c) an ashless sulfur compound that is a thiadiazole, an ashless dithiophosphate, or a phenothiazine, wherein the alkyl hydroxybenzoate compound has a TBN of 100 to 300 mg KOH/g on an oil-free basis. The method of claim 1, wherein the one or more detergents are alkali or alkaline earth metal alkylhydroxybenzoates derived from alkyl groups having 20 to 28 carbon atoms. The method of claim 1, wherein the isomerized normal alpha olefin has an isomerization level (I) of normal alpha olefin of 0.1 to 0.4. 2. The method of claim 1, wherein the alkyl hydroxybenzoate detergent is a calcium alkyl hydroxybenzoate derived from isomerized NAO.