CN115895763A

CN115895763A - Ether-based lubricant compositions, methods and uses

Info

Publication number: CN115895763A
Application number: CN202211673733.2A
Authority: CN
Inventors: I.S.阿当斯; A.布雷克斯皮尔; G.D.兰布; J.M.雷德肖; K.R.韦斯特; R.耶茨
Original assignee: Castrol Ltd
Current assignee: Castrol Ltd
Priority date: 2016-12-16
Filing date: 2017-12-14
Publication date: 2023-04-04
Also published as: EP3555248B1; EP4108745A1; CN110462010B; PL3555248T3; WO2018109123A1; JP7107938B2; CN110462010A; JP2022160461A; JP2020502338A; US20200115651A1; EP3555248A1

Abstract

The present invention provides a lubricant composition for an internal combustion engine comprising a base oil of lubricating viscosity, wherein the base oil comprises an ether-based base stock of formula (a):

(A) Wherein: r _a And R _b Is an aliphatic hydrocarbon groupAnd may be the same or different; wherein R is _a And R _b At least one of which is a branched alkyl, alkoxy-substituted alkyl, or cycloalkyl-substituted alkyl; the lubricant composition further comprises at least one aminic antioxidant and/or at least one phenolic antioxidant; and wherein the total combined amount of aminic antioxidant and phenolic antioxidant in the lubricant composition does not exceed 4.0 wt.% of the lubricant composition. In some embodiments, the ether basestock has formula (1):

(1) Wherein: r is ₁ 、R ₂ 、R ₃ 、R ₄ 、R ₅ And R ₆ As defined herein. The lubricant composition may be used to lubricate surfaces in an internal combustion engine and to improve the fuel economy performance and/or piston cleanliness performance of the engine and/or vehicle, such as a motor vehicle associated with the internal combustion engine.

Description

Ether-based lubricant compositions, methods and uses

The present application is a divisional application of chinese patent application having application number 201780085260.5, application date 2017, 12 and 14, entitled "ether-based lubricant composition, method and use".

Technical Field

The present invention relates to lubricant compositions comprising a base oil comprising certain ether based base stocks (basestock) suitable for use in lubricant compositions intended for use in internal combustion engines. Methods and uses of the lubricant composition and ether basestocks are also provided.

Background

The lubricating composition typically comprises a base oil of lubricating viscosity together with one or more additives to deliver properties including, for example: reduced friction and wear, improved viscosity index, improved dispersancy, detergency, and resistance to oxidation and corrosion. The lubricant base oil may comprise one or more lubricating base stocks.

Lubricant base stocks used in automotive engine lubricants are typically obtained from petrochemical sources, for example they may be obtained as high boiling fractions isolated during the refining of crude oil or as chemical reaction products of feedstocks from petrochemical sources. Lubricant base stocks may also be prepared from fischer-tropsch wax.

Lubricant base stocks may be classified as group I, II, III, IV and V base stocks, as listed in table 1, according to API standard 1509, "engine oil licensing and certification system", 17 th edition, appendix E (10 months 2013, along with 3 months 2015 survey error table).

TABLE 1

Group I base stocks are typically manufactured by known methods including, for example, solvent extraction and solvent dewaxing, or solvent extraction and catalytic dewaxing. Group II and group III base stocks are typically produced by known processes including, for example, catalytic hydrogenation and/or catalytic hydrocracking, and catalytic hydroisomerization. Group IV basestocks include, for example, hydrogenated oligomers of alpha-olefins.

It is desirable for the base stock to have a combination of properties for imparting to the lubricant composition comprising it. In some cases, such as in passenger car engine oils, it may be desirable for the base stock to impart a low viscosity profile on the lubricant composition, as this results in improved fuel economy. In particular, it is desirable that the base stock has a low kinematic viscosity as well as good low temperature viscosity characteristics, such as low pour point or low viscosity as measured using a Micro Rotational Viscometer (MRV). However, the general trend is for the improvement of the viscosity distribution of the base oil (i.e. the reduction of the viscosity parameter) to be accompanied by an undesirable increase in volatility.

In addition, it is desirable that the lubricant compositions exhibit good oxidative stability, particularly when used in internal combustion engines, where oxidative degradation is exacerbated due to the high temperatures encountered in the engine. Good oxidative stability can extend the useful life of the lubricant composition, for example, by reducing oxidative thickening that could otherwise rapidly lead to a loss of fuel economy, and reducing the formation of deposits and sludge that could otherwise ultimately lead to engine failure. Generally, the oxidation stability of lubricant compositions is improved by the addition of antioxidants. Representative antioxidant levels for high performance engine oils may exceed 5% by weight of the lubricant composition. Thus, a significant proportion of the composition may be made up of antioxidants, and these (antioxidants) therefore represent a significant cost component of the lubricant composition. Common antioxidants used in lubricant compositions for use in internal combustion engines include phenolic antioxidants and amine (aminic) antioxidants. However, the presence of phenolic antioxidants is known to have detrimental environmental effects, while the inventors have found that the presence of aminic antioxidants causes turbocharger deposits, piston varnish and copper corrosion, and can also cause compatibility problems with elastomers. In some cases, the negative interactions between the lubricant compositions found in the engine and the oil seal can lead to lubricant loss through oil seal failure.

Accordingly, there is a need for a lubricant composition that: has a low volatility for a given viscosity profile, but is also suitable for use in internal combustion engines. There is also a need for such lubricant compositions: which exhibit good oxidative stability without requiring high antioxidant processing rates (as typically associated with high performance engine oils).

Disclosure of Invention

Accordingly, in a first aspect, there is provided a lubricant composition for an internal combustion engine comprising a base oil of lubricating viscosity, wherein the base oil comprises an ether base stock of formula (a):

wherein: r _a And R _b Are aliphatic hydrocarbon groups and may be the same or different; wherein R is _a And R _b Is a branched alkyl, alkoxy-substituted alkyl, or cycloalkyl-substituted alkyl;

the lubricant composition further comprises at least one aminic antioxidant and/or at least one phenolic antioxidant; and is

Wherein the total combined amount of the aminic antioxidant and the phenolic antioxidant in the lubricant composition is no more than 4.0 wt.% of the lubricant composition.

In a particularly preferred embodiment, the ether basestock of the lubricant composition is selected from a subset of the compounds of formula (a), i.e., the compounds of formula (1):

wherein: r ₁ And R ₂ Is alkyl or, together with the carbon atom to which they are attached, is cycloalkyl;

R ₃ 、R ₄ and R ₅ Is H or alkyl;

R ₆ is alkyl or

Wherein: r ₇ And R ₈ Is H, alkyl, or with itThe carbon atoms to which they are attached together are cycloalkyl;

R ₉ is H or alkyl;

x is alkylene or absent; and

p is 0, 1, 2 or 3; and is

m and n are 0, 1, 2 or 3, with the proviso that when R is ₄ And R ₅ When it is H, m is 0.

Methods of making the lubricant compositions are also provided.

Also provided are methods of lubricating a surface using the lubricant compositions, and the use of the lubricant compositions for lubricating a surface.

Methods and uses are also provided for improving the oxidative stability of the lubricant composition, as well as for improving the fuel economy performance and/or piston cleanliness performance of an engine and/or vehicle (e.g., a motor vehicle associated with an internal combustion engine).

Drawings

FIG. 1 is a graph of percent increase in kinematic viscosity at 100 ℃ versus time corresponding to CEC-L-109 test results for a blend composition containing a Guerbet (alcohol) derived basestock (GE 3) and/or group III basestock (Yubase 4) along with varying amounts of aminic and/or phenolic oxidants, and other lubricant additives.

Detailed Description

There is provided a lubricant composition for an internal combustion engine comprising a base oil of lubricating viscosity, wherein the base oil comprises an ether-based base stock of formula (a):

For the purposes of the present invention, the following terms as used herein, unless otherwise indicated, shall be understood to have the following meanings:

the term "aliphatic hydrocarbon group" as used herein refers to a group comprising hydrogen and carbon atoms, wherein one or more carbon atoms may optionally be replaced by-O-, which group may be saturated or unsaturated, preferably saturated, and contains 1 to 40 carbon atoms. Examples of the hydrocarbon group include hydrocarbon groups containing 2 to 28 carbon atoms, for example, 3 to 26 carbon atoms or 4 to 24 carbon atoms. In case one or more carbon atoms are replaced by-O-, preferably from 2% to 35% or from 5% to 25% of the carbon atoms are replaced by-O-. In other examples, the aliphatic hydrocarbon group has 1 to 3 carbon atoms replaced with-O-, for example 2 carbon atoms replaced with-O-. In other examples, no carbon atom is replaced with-O-.

Examples of aliphatic hydrocarbon groups include acyclic groups, non-aromatic cyclic groups, and groups containing both acyclic moieties and non-aromatic cyclic moieties. The aliphatic hydrocarbon group may be straight or branched. Aliphatic hydrocarbon groups include the monovalent and polyvalent groups specified. Examples of monovalent hydrocarbon groups include alkyl, alkenyl, alkynyl, and carbocyclyl (e.g., cycloalkyl or cycloalkenyl).

The term "alkyl" as used herein refers to a monovalent straight or branched chain alkyl moiety containing from 1 to 40 carbon atoms. Examples of alkyl groups include alkyl groups containing 1 to 30 carbon atoms, such as 2, 3, or 4 carbon atoms to 24, 25, or 26 carbon atoms, such as 1 to 20 carbon atoms, 1 to 14 carbon atoms, 2 to 26 carbon atoms, and 3 to 24 carbon atoms. Particular examples include alkyl groups containing 1, 2, 3,4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, and 30 carbon atoms. Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl and the like. Unless otherwise specifically indicated, the term "alkyl" excludes optional substituents.

The term "cycloalkyl" as used herein refers to a monovalent saturated aliphatic hydrocarbon moiety containing from 3 to 40 carbon atoms and containing at least one ring, wherein the ring has at least 3 ring carbon atoms. The cycloalkyl groups referred to herein may optionally have an alkyl group attached thereto. Examples of cycloalkyl groups include cycloalkyl groups containing 3 to 16 carbon atoms, for example 3 to 10 carbon atoms. Particular examples include cycloalkyl groups containing 3,4, 5 or 6 ring carbon atoms. Examples of cycloalkyl groups include groups belonging to a monocyclic, polycyclic (e.g., bicyclic) or bridged ring system. Examples of cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and the like.

The term "alkenyl" as used herein refers to a monovalent straight or branched chain hydrocarbon radical (alkyl group) containing 2 to 40 carbon atoms and additionally containing at least one carbon-carbon double bond having either the E or Z configuration, unless specified. Examples of the alkenyl group include alkenyl groups having 2 to 28 carbon atoms, for example, 3 to 26 carbon atoms, for example, 4 to 24 carbon atoms. Particular examples include alkenyl groups containing 2, 3,4, 5 or 6 carbon atoms. Examples of alkenyl groups include vinyl, 2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, and the like.

The term "alkylene" refers to a divalent straight or branched chain saturated hydrocarbon radical consisting of hydrogen and carbon atoms and containing from 1 to 30 carbon atoms. Examples of the alkylene group include alkylene groups having 1 to 20 carbon atoms, for example, 1 to 12 carbon atoms, for example, 1 to 10 carbon atoms. Particular examples include alkylene groups containing 1, 2, 3,4, 5 or 6 carbon atoms.

The term "alkoxy" as used herein refers to an-O-alkyl group, wherein alkyl is as defined herein. In some examples, alkoxy groups contain 1 to 40 carbon atoms, such as 1 to 28 carbon atoms or 1 to 26 carbon atoms, or 1 to 24 carbon atoms, such as 1 to 10 carbon atoms. Particular examples include alkoxy groups containing 1, 2, 3,4, 5 or 6 carbon atoms. Examples of alkoxy groups include methoxy, ethoxy, propoxy, isopropoxy, butoxy, tert-butoxy, pentyloxy, hexyloxy, and the like.

The terms "alkoxy-substituted alkyl" and "cycloalkyl-substituted alkyl" refer to straight or branched chain alkyl groups in which one hydrogen of the alkyl chain is replaced by an alkoxy or cycloalkyl group, respectively, as described herein.

In some embodiments, R of formula (A) _a And R _b Independently selected from the group consisting of alkyl, alkoxy-substituted alkyl and cycloalkyl-substituted alkyl, with the proviso that at R _a And R _b In the case of both alkyl radicals, R _a And R _b At least one of which is a branched alkyl group. In a preferred embodiment, when R _a And R _b When both are alkyl, R _a And R _b Are all branched alkyl groups.

In some embodiments, R of formula (A) _a And R _b Is independently selected from C _1-30 Alkyl radicals, e.g. C _2-20 An alkyl group; c _5-30 Cycloalkyl-substituted alkyl radicals, e.g. C _5-25 Cycloalkyl-substituted alkyl; or C _2-30 Alkoxy-substituted alkyl radicals, e.g. C _2-20 Alkoxy-substituted alkyl.

In some embodiments, R of formula (A) _a Ratio R _b Containing more carbon atoms.

In some embodiments, R of formula (A) _a Containing from 12 to 30 carbon atoms, preferably from 12 to 26 carbon atoms, and/or R _b Containing from 2 to 20 carbon atoms, preferably from 2 to 12 carbon atoms.

In a particularly preferred embodiment, the ether basestock of the lubricant composition is a compound of formula (1):

R ₃ 、R ₄ and R ₅ Is H or alkyl;

R ₆ is alkyl or

Wherein: r ₇ And R ₈ Is H, alkyl, or together with the carbon atom to which they are attached is cycloalkyl;

R ₉ is H or alkyl;

x is alkylene or absent; and

p is 0, 1, 2 or 3; and is provided with

In some embodiments, R ₁ And R ₂ Is C _1-15 Alkyl radicals, or together with the carbon atom to which they are attached, C _5-30 Cycloalkyl radicals, e.g. C _2-12 Alkyl radicals, or together with the carbon atom to which they are attached, C _5-25 A cycloalkyl group.

In some embodiments, R ₃ 、R ₄ And R ₅ Is H or C _1-15 Alkyl radicals, e.g. H or C _2-12 An alkyl group. Preferably, R ₅ Is H.

In some embodiments, R ₆ Is C _1-20 Alkyl or

E.g. C _1-16 Alkyl or

In some embodiments, R ₇ And R ₈ Is H, C _1-20 Alkyl radicals, or together with the carbon atom to which they are attached, C _5-30 Cycloalkyl radicals, e.g. H, C _2-12 Alkyl radicals, or together with the carbon atom to which they are attached, C _5-25 A cycloalkyl group. Preferably, R ₇ And R ₈ Is C _1-20 Alkyl radicals, e.g. C _2-12 An alkyl group.

In some embodiments, R ₉ Is H or C _1-20 Alkyl radicals, e.g. H or C _2-12 An alkyl group. Preferably, R ₉ Is H.

In some embodiments, X is C _1-20 Alkylene radicals, e.g. C _3-15 An alkylene group.

In some embodiments, p is 0, 1 or 2, e.g., 0 or 1.

In some embodiments, m and n are 0, 1 or 2, e.g., 0 or 1.

R ₁ And R ₂ As described, alkyl, or together with the carbon atom to which they are attached, cycloalkyl. It will be understood that at R ₁ And R ₂ In the case of both alkyl groups, they may be the same as or different from each other. Similar considerations apply to other substituents defined as part of a group of substituents. Thus, this consideration applies to, for example, R ₃ 、R ₄ And R ₅ (ii) a Application to R ₇ And R ₈ (ii) a And to the values taken by m and n. For example, in the reaction of R ₃ 、R ₄ And R ₅ Where described as H or alkyl, it will be understood that R ₃ 、R ₄ And R ₅ Each may be H, R ₃ 、R ₄ And R ₅ Each may be alkyl, or R ₃ 、R ₄ And R ₅ May be H and R ₃ 、R ₄ And R ₅ May be an alkyl group. At R ₃ 、R ₄ And R ₅ Or a subset thereof is alkyl, R ₃ 、R ₄ And R ₅ Each may be the same alkyl group, or they may be different alkyl groups. In contrast, R is used at several positions in the formula ₁ (or any other symbol) is used to indicate that the same group is present at each of these positions.

In each of the embodiments disclosed herein, the ether compounds of the lubricant composition may contain a total of from about 20 to about 50 carbon atoms. For example, the total number of carbons in the ether compound can be about 25 to about 45, such as about 28 to about 40 or about 28 to about 36.

As previously indicated, the alkyl and alkylene groups mentioned herein (i.e., may be represented by R) _a 、R _b 、R ₁ 、R ₂ 、R ₃ 、R ₄ 、R ₅ 、R ₆ 、R ₇ 、R ₈ 、R ₉ And those represented by X) may be a straight-chain alkyl group or an alkylene group, but they may also be branched. In some embodiments, each alkyl and each alkylene contains a single branch point or is a straight chain alkyl or alkylene. For example, when R is _a And R _b In the case of both alkyl groups, at least one of these alkyl groups is branched, preferably both branched. In some embodiments, for example with respect to R ₁ 、R ₂ 、R ₃ 、R ₄ 、R ₅ 、R ₆ 、R ₇ 、R ₈ 、R ₉ And X groups, alkyl and alkylene being straight chain alkyl or alkylene. It will be understood that, except for alkyl branches (if present), alkyl and alkylene groups are unsubstituted and, therefore, may not contain any atoms other than carbon or hydrogen, unless otherwise specified.

The compounds of formula (a) and/or formula (1) may have a kinematic viscosity at 40 ℃ of less than about 25cSt, for example less than about 20cSt or less than about 17 cSt. The compound can have a kinematic viscosity at 100 ℃ of less than about 7cSt, such as less than about 5cSt or less than about 4 cSt. The compound may have a viscosity index greater than about 100, such as greater than about 110 or greater than about 120. Kinematic viscosity at 40 ℃ and kinematic viscosity at 100 ℃ can be measured according to astm d 7279. The viscosity index can be measured according to astm d 2270.

The compound may have a Noackvollatity (Noackvollatity) of less than about 26 wt%, such as less than about 20 wt%, less than about 16 wt%, or less than about 12 wt%. Noak volatility can be measured according to CEC-L-40-A-93.

The compound is at 150 ℃ and 10 ℃ ⁶ s ^-1 May have a viscosity of no greater than 1.7cP, such as no greater than 1.5cP, at shear rates of (a). Such high temperature high shear viscosity can be measured according to CEC-L-36-A-90.

The ether compounds described herein may be used to reduce the total amount of antioxidant additives required in a lubricant composition (the antioxidants comprising at least one aminic antioxidant and/or at least one phenolic antioxidant) in order for the lubricant composition to achieve a particular level of oxidative stability performance, preferably in the case where the lubricant composition is used in an internal combustion engine (e.g., one associated with a motor vehicle). In a preferred embodiment, the lubricant composition for improvement by use of the ether compounds described herein comprises an aminic antioxidant and/or a phenolic antioxidant and has a total combined amount of aminic antioxidant and phenolic antioxidant in the lubricant composition of no more than 4.0%, no more than 3.0%, no more than 2.5%, or no more than 2.0% by weight of the lubricant composition. In preferred embodiments, the lubricant composition for improvement by use of the ether compounds described herein comprises an aminic antioxidant and/or a phenolic antioxidant, and has a total combined amount of aminic antioxidant and phenolic antioxidant of at least 0.25%, at least 0.5%, or at least 1.0% in the lubricant composition by weight of the lubricant composition.

Thus, the following method is also provided: reducing the total amount of antioxidant additives required in the lubricant composition, said antioxidants comprising at least one aminic antioxidant and/or at least one phenolic antioxidant, in order for the lubricant composition to achieve a specific level of oxidative stability performance, the method comprising the step of providing or supplying at least one ether compound described herein to the lubricant composition. In a preferred embodiment, the lubricant composition is used in an internal combustion engine, such as that associated with a motor vehicle. In a preferred embodiment, the lubricant composition for improvement by the ether compounds described herein comprises an aminic antioxidant and/or a phenolic antioxidant and has a total combined amount of aminic antioxidant and phenolic antioxidant in the lubricant composition of no more than 4.0%, no more than 3.0%, no more than 2.5%, or no more than 2.0% by weight of the lubricant composition. In a preferred embodiment, the lubricant composition for improvement by the ether compounds described herein comprises an aminic antioxidant and/or a phenolic antioxidant and has a total combined amount of aminic antioxidant and phenolic antioxidant of at least 0.25%, at least 0.5%, or at least 1.0% in the lubricant composition by weight of the lubricant composition.

The lubricant compositions described herein may be used to improve fuel economy performance and/or piston cleanliness performance of an engine and/or vehicle (e.g., a motor vehicle associated with an internal combustion engine). Accordingly, a method of improving fuel economy performance and/or piston cleanliness performance of an engine and/or vehicle (e.g., a motor vehicle associated with an internal combustion engine) is provided, comprising the step of providing the engine and/or vehicle with a lubricant composition as described herein.

The ether compounds described herein may have a pour point of less than-10 ℃, e.g., less than about-25 ℃ or less than about-35 ℃. Pour point can be measured according to astm d 5950.

The ether compound may have a cold crankcase simulator viscosity (cold-crank casedesigning viscosity) of less than about 1800cP, such as less than about 1500cP or less than about 1200cP at-35 ℃, for example as measured according to astm d 5293.

The ether compound may have a DSC oxidation onset temperature of greater than about 165 ℃, e.g., greater than about 175 ℃, or greater than about 185 ℃, e.g., as measured according to astm e2009 (method B).

In particular embodiments, the ether compounds of formula (a) or formula (1) may have a kinematic viscosity at 100 ℃ of about 3 to about 4cSt and a noack volatility of less than about 20 wt%, e.g., less than about 16 wt% or less than about 12 wt%; or a kinematic viscosity at 100 ℃ of about 2 to about 3cSt and a Noah volatility of less than about 40 wt%, for example less than about 30 wt%.

The ether compounds of formula (A) or formula (1) are particularly suitable for blending into lubricant compositions. In particular, the compounds are miscible with conventional base stocks, including hydrocarbon base stocks, and with conventional lubricant additives. Additionally, the compounds may be used in relatively high amounts (e.g., in amounts greater than about 10 wt.%, such as greater than about 20 wt.% or greater than about 30 wt.%) in the lubricant composition while meeting elastomer compatibility requirements for the lubricant composition.

The compounds of formula (a) and formula (1) may be prepared from a wide range of commercially available starting materials.

In some embodiments, the compound is prepared from a biologically derived feedstock. For example, the compound may contain greater than about 50 wt%, such as greater than about 70 wt% or greater than about 80 wt% biobased carbon. Bio-based carbon content of the compound can be measured according to astm d 6866.

Guerbet-derived (Guerbet-derived) basestocks

In a preferred embodiment, the compound of formula (1) is derived from a β -alkylated alcohol. In these embodiments, the compound may have formula (2):

R ₃ and R ₅ Is H or alkyl;

R ₄ is an alkyl group;

R ₆ is alkyl or

R ₉ is H or alkyl;

x is alkylene or absent; and

p is 0, 1, 2 or 3; and is

n is 0, 1, 2 or 3.

In some embodiments, R ₁ And R ₂ Is C _1-15 Alkyl, or together with the carbon atom to which they are attached, C _5-30 Cycloalkyl radicals, e.g. C _2-12 Alkyl radicals, or together with the carbon atom to which they are attached, C _5-25 A cycloalkyl group. Preferably, R ₁ And R ₂ Is C _1-15 Alkyl radicals, e.g. C _2-12 An alkyl group.

In some embodiments, R ₃ And R ₅ Is H or C _1-15 Alkyl radicals, e.g. H or C _2-12 An alkyl group. Preferably, R ₃ And R ₅ Is H.

In some embodiments, R ₄ Is C _1-15 Alkyl radicals, e.g. C _2-12 An alkyl group.

In some embodiments, R ₆ Is C _1-15 Alkyl or

E.g. C _1-12 Alkyl or

In some embodiments, p is 0, 1 or 2, e.g., 0 or 1.

In some embodiments, n is 0, 1 or 2, e.g., 0 or 1.

Where the compound is derived from a β -alkylated alcohol, it is preferably at least partially derived from a guerbet alcohol. The compound at least partially derived from a guerbet alcohol can have formula (3):

wherein: r is ₁ Is an alkyl group;

R ₃ and R ₅ Is H or alkyl;

R ₄ is an alkyl group;

R ₆ is alkyl or

R ₉ is H or alkyl;

x is alkylene or absent; and

p is 0, 1, 2 or 3; and is provided with

n is 0, 1, 2 or 3.

In some embodiments, R ₁ Is C _1-12 Alkyl radicals, e.g. C _2-10 An alkyl group.

In some embodiments, R ₃ Is H or C _1-12 Alkyl radicals, e.g. H or C _2-10 An alkyl group. Preferably, R ₃ Is H.

In some embodiments, R ₅ Is H or C _1-15 Alkyl radicals, e.g. H or C _2-12 An alkyl group. Preferably, R ₅ Is H.

In some embodiments, R ₆ Is C _1-15 Alkyl or

E.g. C _1-12 Alkyl or

Preferably, R ₆ Is C _1-15 Alkyl radicals, e.g. C _1-12 An alkyl group.

In some embodiments, R ₇ And R ₈ Is H, C _1-20 Alkyl radicals, or together with the carbon atom to which they are attached, C _5-30 Cycloalkyl radicals, e.g. H, C _2-12 Alkyl radicals, or the carbons to which they are attachedThe atoms together being C _5-25 A cycloalkyl group. Preferably, R ₇ And R ₈ Is C _1-20 Alkyl radicals, e.g. C _2-12 An alkyl group.

In some embodiments, p is 0, 1 or 2, e.g., 0 or 1.

In some embodiments, n is 0, 1 or 2, e.g., 0 or 1.

A part of the compound of formula (3) has a structure derivable from a Guerbet alcohol (i.e., contains R ₁ And R ₃ Without the other moiety needing to be derived from a guerbet alcohol (i.e., containing R) ₄ 、R ₅ And R ₆ Part(s). However, in a preferred embodiment, the compound may be derived from a combination of two guerbet alcohols. The compound prepared in this manner may have formula (4):

wherein: r ₁ And R ₄ Is an alkyl group;

R ₃ and R ₅ Is H or alkyl.

In some embodiments, R ₁ And R ₄ Is C _1-12 Alkyl radicals, e.g. C _2-10 An alkyl group.

In some embodiments, R ₃ And R ₅ Is H or C _1-12 Alkyl radicals, e.g. H or C _2-10 An alkyl group. Preferably, R ₃ And R ₅ Is H.

In particular embodiments: r ₁ Is C _4-12 Alkyl radicals, e.g. C _6-10 An alkyl group;

R ₃ is H;

R ₄ is C _1-10 Alkyl radical, examplesSuch as C _2-8 An alkyl group; and is

R ₅ Is H.

Two different Guerbet alcohols may be combined to form a compound of formula (4), in which case R ₁ And R ₄ May be different. Or, R ₃ And R ₅ May be different. In some embodiments, R ₁ And R ₄ Is different from, and R ₃ And R ₅ And also different.

However, in some embodiments, the compound may be derived from a reaction in which the same guerbet alcohol is bound. The compound prepared in this manner may have formula (5):

wherein: r ₁ Is an alkyl group; and is

R ₃ Is H or alkyl.

In some embodiments, R ₁ Is C _1-10 Alkyl radicals, e.g. C _2-9 An alkyl group.

In some embodiments, R ₃ Is H or C _1-9 Alkyl radicals, e.g. H or C _2-8 An alkyl group. Preferably, R ₃ Is H.

In particular embodiments: r ₁ Is C _3-10 Alkyl radicals, e.g. C _4-8 An alkyl group; and is

R ₃ Is H.

Compounds derived from Guerbet alcohols include the compounds GE1-GE3, GE5, GE7-GE9, SE1, SE2 and TE1 shown in Table 2.

The guerbet alcohol may be prepared, for example, by dimerizing a primary alcohol in a guerbet reaction to form a β -alkylated alcohol product:

wherein R is ₁ And R ₃ As previously defined;

and/or:

wherein R is ₄ And R ₅ As previously defined.

The guerbet reaction is well known to the skilled person. The reaction is generally carried out at elevated temperature in the presence of a catalyst.

The compounds can be prepared from guerbet alcohols, for example according to the following reaction:

wherein: y is a leaving group; and is

R ₁ 、R ₃ 、R ₄ 、R ₅ 、R ₆ And n is as previously defined for the compound of formula (3).

In the case of combining two guerbet alcohols to form a compound, one guerbet alcohol can first be modified so that it contains a leaving group Y, and then the compound is prepared:

/>

then:

or:

then:

wherein: y is a leaving group; and is

R ₁ 、R ₃ 、R ₄ And R ₅ As previously defined for the compound of formula (4).

Where the same guerbet alcohols are combined to form a compound, they may be combined, for example, according to the following reaction:

then:

wherein: y is a leaving group; and is

R ₁ And R ₃ As previously defined for the compound of formula (5).

The skilled worker is aware of the methods and reaction conditions for modifying Guerbet alcohols such that they contain a leaving group Y. For example, the mesylate group can be introduced by reacting a guerbet alcohol with methanesulfonyl chloride in the presence of triethylamine. Bromine groups can be introduced by reacting a Guerbet alcohol with N-bromosuccinimide and triphenylphosphine.

The skilled worker knows the methods and reaction conditions for carrying out the etherification reaction. A base (e.g., potassium hydroxide or potassium tert-butoxide), a catalyst (e.g., starks catalyst: N-Methyl-N, N-tri-N-octyl-ammonium chloride (N-Methyl-N, N-tricapryloctan-1-ammonium chloride)), or both, may be used in the above-described compound formation reaction (i.e., etherification reaction).

In the above compound formation reaction, Y may be any suitable leaving group, such as a halogen (e.g. bromo, chloro or iodo) or a sulfonate (e.g. mesylate or tosylate).

Secondary and tertiary ether basestocks

In some preferred embodiments, the compound of formula (1) is a secondary or tertiary ether compound. In these embodiments, the compound may have formula (6):

wherein: r ₁ And R ₂ Is alkyl or, together with the carbon to which they are attached, is cycloalkyl;

R ₃ 、R ₄ and R ₅ Is H or alkyl;

R ₆ is alkyl or

Wherein: r is ₇ And R ₈ Is H, alkyl, or together with the carbon atom to which they are attached is cycloalkyl;

R ₉ is H or alkyl;

x is alkylene or absent; and

p is 0, 1, 2 or 3; and is

n is 0, 1, 2 or 3.

In some embodiments, R ₁ And R ₂ Is C _1-15 Alkyl radicals, or together with the carbon atom to which they are attached, C _5-30 Cycloalkyl radicals, e.g. C _2-12 Alkyl, or together with the carbon atom to which they are attached, C _5-25 A cycloalkyl group. Preferably, R ₁ And R ₂ Is C _1-15 Alkyl radicals, e.g. C _2-12 An alkyl group.

In some embodiments, R ₆ Is C _1-20 Alkyl or

E.g. C _1-16 Alkyl or

In some embodiments, R ₇ And R ₈ Is H, C _1-20 Alkyl, or together with the carbon atom to which they are attached, C _5-30 Cycloalkyl radicals, e.g. H, C _2-12 Alkyl radicals, or together with the carbon atom to which they are attached, C _5-25 A cycloalkyl group. Preferably, R ₇ And R ₈ Is C _1-20 Alkyl radicals, e.g. C _2-12 An alkyl group.

In some embodiments, p is 0, 1 or 2, e.g., 0 or 1.

In some embodiments, n is 0, 1 or 2, e.g., 0 or 1.

The secondary and tertiary ether compounds may have formula (7):

R ₃ 、R ₄ and R ₅ Is H or alkyl; and is provided with

R ₆ Is an alkyl group.

In some embodiments, R ₁ And R ₂ Is C _1-15 Alkyl, or together with the carbon to which they are attached, C _5-30 Cycloalkyl radicals, e.g. C _2-12 Alkyl, or together with the carbon to which they are attached, is C _5-25 A cycloalkyl group.

In some embodiments, R ₃ 、R ₄ And R ₅ Is H or C _1-15 Alkyl radicals, examplesSuch as H or C _2-12 An alkyl group. Preferably, R ₅ Is H.

In some embodiments, R ₆ Is C _1-20 Alkyl radicals, e.g. C _1-16 An alkyl group.

The compound may be a secondary ether compound of formula (8):

R ₄ and R ₅ Is H or alkyl; and is

R ₆ Is an alkyl group.

In some embodiments, R ₁ And R ₂ Is C _1-15 Alkyl radicals, e.g. C _2-12 An alkyl group.

In other embodiments, the secondary ether may be obtained from a cyclic compound. In this case, R ₁ And R ₂ Together with the carbon to which they are attached form cycloalkyl, e.g. C _5-30 Cycloalkyl or C _5-25 A cycloalkyl group. The cycloalkyl group may contain cyclopentyl, cyclohexyl, or cycloheptyl groups, optionally having one or more alkyl groups attached thereto, e.g., C _1-12 Alkyl or C _1-8 An alkyl group.

In some embodiments, R ₄ And R ₅ Is H or C _1-15 Alkyl radicals, e.g. H or C _2-12 An alkyl group. Preferably, R ₅ Is H.

In particular embodiments: r ₁ And R ₂ Is C _3-12 Alkyl radicals, e.g. C _5-10 An alkyl group;

R ₄ and R ₅ Is H; and is

R ₆ Is C _4-20 Alkyl radicals, e.g. C _6-15 An alkyl group.

In other particular embodimentsIn the embodiment: r ₁ And R ₂ Is C _3-12 Alkyl radicals, e.g. C _5-10 An alkyl group;

R ₄ is C _3-12 Alkyl radicals, e.g. C _5-10 An alkyl group;

R ₅ is H; and is provided with

R ₆ Is C _3-12 Alkyl radicals, e.g. C _5-10 An alkyl group.

The compound may be a tertiary ether compound of formula (9):

R ₃ is an alkyl group;

R ₄ and R ₅ Is H or alkyl; and is

R ₆ Is an alkyl group.

In some embodiments, R ₁ And R ₂ Is C _1-15 Alkyl, or together with the carbon to which they are attached, C _5-30 Cycloalkyl radicals, e.g. C _2-12 Alkyl, or together with the carbon to which they are attached, is C _5-25 A cycloalkyl group. Preferably, R ₁ And R ₂ Is C _1-15 Alkyl radicals, e.g. C _2-12 An alkyl group.

In some embodiments, R ₃ Is C _1-12 Alkyl radicals, e.g. C _1-10 An alkyl group.

In some embodiments, R ₄ And R ₅ Is H or C _1-15 Alkyl radicals, e.g. H or C _2-12 An alkyl group.

In particular embodiments: r ₁ And R ₂ Is C _2-12 Alkyl radicals, e.g. C _4-10 An alkyl group;

R ₃ is C _1-10 Alkyl radicals, e.g. C _1-8 An alkyl group;

R ₄ and R ₅ Is H; and is

R ₆ Is C _4-20 Alkyl radicals, e.g. C _6-15 An alkyl group.

In other particular embodiments: r ₁ 、R ₂ And R ₃ Is C _2-12 Alkyl radicals, e.g. C _4-10 An alkyl group;

R ₃ is C _1-10 Alkyl radicals, e.g. C _1-8 An alkyl group;

R ₄ is C _3-12 Alkyl radicals, e.g. C _5-10 An alkyl group;

R ₅ is H; and is provided with

R ₆ Is C _3-12 Alkyl radicals, e.g. C _5-10 An alkyl group.

Examples of secondary and tertiary ether compounds include SE1, SE2, and TE1 as shown in table 2.

Secondary and tertiary ether compounds may be prepared according to the following reaction:

or:

wherein: y is a leaving group; and is

R ₁ 、R ₂ 、R ₃ 、R ₄ 、R ₅ 、R ₆ And n is as previously defined for the compound of formula (6).

Similarly:

or:

wherein: y is a leaving group; and is

R ₁ 、R ₂ 、R ₃ 、R ₄ 、R ₅ And R ₆ As previously defined for the compound of formula (7).

The skilled person will be aware of the methods and reaction conditions used to carry out these etherification reactions. For example, the reaction may be carried out in the presence of magnesium sulfate, sulfuric acid, and dichloromethane.

The secondary and tertiary alcohol starting materials used in the etherification reaction will generally be commercially available or they may be obtained from commercially available ketones.

The group may be prepared by introducing the leaving group Y into the alcohol starting material

The skilled person is aware of the methods and reaction conditions for introducing a leaving group into an alcohol.

In the above secondary and tertiary ether compound formation reactions, Y may be any suitable leaving group, such as a halogen (e.g., bromine, chlorine, or iodine) or a sulfonate (e.g., a mesylate or tosylate).

Secondary or tertiary ethers derived from Guerbet alcohols

In some embodiments, the compound may comprise an ether that is derived on one side from a secondary or tertiary alcohol and on the other side from a guerbet alcohol. In these embodiments, the compound may have formula (10):

wherein: r ₁ And R ₄ Is an alkyl group;

R ₃ and R ₅ Is H or alkyl;

R ₆ is alkyl or

R ₉ is H or alkyl;

x is alkylene or absent; and is

And p is 0, 1, 2 or 3.

In some embodiments, R ₆ Is C _1-15 Alkyl or

E.g. C _1-12 Alkyl or

In some embodiments, p is 0, 1 or 2, e.g., 0 or 1.

Examples of secondary and tertiary ether compounds derived from guerbet alcohols include compounds SE1, SE2 and TE1 as shown in table 2.

Diether base stocks

It is generally preferred that the compound of formula (1) is a monoether. However, in some embodiments, the compound is a diether compound. Such compounds may have formula (11):

R ₃ 、R ₄ and R ₅ Is H or alkyl;

R ₇ and R ₈ Is H, alkyl, or together with the carbon atom to which they are attached is cycloalkyl;

R ₉ is H or alkyl;

x is alkylene or absent;

p is 0, 1, 2 or 3; and is

m and n are 0, 1, 2 or 3.

In some embodiments, R ₁ And R ₂ Is C _1-15 Alkyl, or together with the carbon to which they are attached, C _5-30 Cycloalkyl radicals, e.g. C _2-12 Alkyl, or together with the carbon to which they are attached, C _5-25 A cycloalkyl group. Preferably, R ₁ And R ₂ Is C _1-15 Alkyl radicals, e.g. C _2-12 An alkyl group.

In some embodiments, R ₃ 、R ₄ And R ₅ Is H or C _1-15 Alkyl radicals, e.g. H or C _2-12 An alkyl group. Preferably, R ₃ And R ₅ Is H.

In some embodiments, p is 0, 1 or 2, e.g., 0 or 1.

In some embodiments, m and n are 0, 1 or 2, e.g., 0 or 1.

In some embodiments, the diether compound can contain two ether groups, at least one of which is derived from a β -alkylated alcohol. In such embodiments, the compound may have formula (12):

R ₃ 、R ₄ and R ₅ Is H or alkyl;

R ₉ is H or alkyl;

x is alkylene or absent;

p is 0, 1, 2 or 3; and is

n is 0, 1, 2 or 3.

In some embodiments, R ₁ And R ₂ Is C _1-15 Alkyl radicals, or together with the carbon atom to which they are attached, C _5-30 Cycloalkyl radicals, e.g. C _2-12 An alkyl group, which is a radical of an alkyl group,or together with the carbon atom to which they are attached is C _5-25 A cycloalkyl group. Preferably, R ₁ And R ₂ Is C _1-15 Alkyl radicals, e.g. C _2-12 An alkyl group.

In some embodiments, R ₃ 、R ₄ And R ₅ Is H or C _1-15 Alkyl radicals, e.g. H or C _2-12 An alkyl group. Preferably, R ₃ And R ₅ Is H. Preferably, R ₄ Is C _1-15 Alkyl radicals, e.g. C _2-12 An alkyl group.

In some embodiments, p is 0, 1 or 2, e.g., 0 or 1.

In some embodiments, n is 0, 1 or 2, e.g., 0 or 1.

Examples of guerbet (alcohol) derived base stocks GE1-GE9, secondary ether base stocks SE1 and SE2, and tertiary ether base stocks TE1 of formula (1) that may be preferably used in connection with the present application are shown in table 2.

TABLE 2

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Base oil and lubricant composition

The ether compounds of formula (a), or a subset of formula (1) thereof, are used as part of the base oil according to the present invention.

The base oil may contain an amount of a compound of formula (a), or a subset of formula (1) thereof, sufficient to impart the beneficial properties of the compound to the base oil.

In some embodiments, the base oil comprises greater than about 5 wt%, such as greater than about 25 wt% or greater than about 40 wt% of the ether compound of formula (a), or a subset of formula (1) thereof. The base oil may comprise up to about 100%, for example up to about 90%, of compounds of formula (a) or a subset of formula (1) thereof. The compound of formula (a) or a subset of formula (1) thereof in the base oil may consist of a single compound or a combination of compounds of formula (a) or a subset of formula (1) thereof.

The remainder of the base oil may consist of base stocks which are not compounds of formula (a) and formula (1). Base stocks other than those of formula (a) and formula (1) suitable for use in the base oil include non-aqueous base stocks such as group I, group II, group III, group IV and group V base stocks. The remainder of the base oil may comprise a single base stock or a combination of base stocks different from those of formula (a) and formula (1).

The base oil is used as part of the lubricant composition according to the present invention.

The lubricant composition may contain an amount of base oil sufficient to impart the beneficial properties of the compound of formula (a) or a subset of formula (1) thereof, onto the lubricating composition.

In some embodiments, the lubricant composition comprises greater than about 50 wt.%, such as greater than about 65 wt.% or greater than about 80 wt.% base oil. The base oil may be composed of a single base oil or a combination of base oils comprising compounds of formula (a) or a subset of formula (1) thereof.

The lubricant composition comprises at least one aminic antioxidant and/or at least one phenolic antioxidant, wherein the total combined amount of aminic antioxidant and phenolic antioxidant does not exceed 4% by weight of the lubricant composition. In preferred embodiments, the lubricant composition has a total combined amount of aminic and phenolic antioxidants in the lubricant composition of no more than 3.0%, no more than 2.5%, or no more than 2.0% by weight of the lubricant composition. In preferred embodiments, the lubricant composition has a total combined amount of at least 0.25%, at least 0.5%, or at least 1.0% of the aminic antioxidant and the phenolic antioxidant in the lubricant composition, by weight of the lubricant composition.

Any total combined amount of aminic and phenolic antioxidants may be present in the lubricant compositions of the present invention, provided that it does not exceed 4% by weight of the lubricant composition. Thus, any subrange of the antioxidant concentration within the above range can be used in accordance with the invention. For example, all subranges forming a combination of a lower weight percent limit (0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5) along with an upper weight percent limit (4.0, 3.9, 3.8, 3.7, 3.6, 3.5, 3.4, 3.3, 3.2, 3.1, 3.0, 2.9, 2.8, 2.7, 2.6, 2.5, 2.4, 2.3, 2.2, 2.1, or 2.0) can be utilized in accordance with the invention.

A particular advantage of the present invention relates to the oxidative stability imparted to the lubricant composition by the presence of the ether compounds of formula (a) or a subset of formula (1) thereof. This allows for the achievement of desirable oxidation stability properties in the composition without the need for the same total concentration of aminic and/or phenolic antioxidants as would normally be required in a comparative lubricant composition formulated without any ether compound of formula (a) or formula (1). The representative total combined level of aminic and/or phenolic antioxidants of the high performance engine oil may exceed 5% by weight of the lubricant composition. The present invention enables the use of much lower total combined concentrations of aminic and/or phenolic antioxidants to achieve the same or better oxidative stability properties, for example, both before and during use in an internal combustion engine, as compared to conventional lubricant compositions that do not contain any ether compound of formula (a) or formula (1), and that contain the same, but higher concentrations of aminic and/or phenolic antioxidants. This is particularly beneficial from a cost standpoint as well as from a lubricant composition life, fuel economy, and piston cleanliness standpoint. The reduction of amine antioxidants in lubricant compositions for internal combustion engines is of particular benefit in reducing turbocharger deposits as well as reducing copper corrosion and increasing elastomer compatibility. At the same time, the reduction of phenolic antioxidants results in improved environmental toxicity of the lubricant composition.

It is common to add one or more anti-wear additives to lubricant compositions, examples of which include Zinc Dihydrocarbyl Dithiophosphates (ZDDPs). Additionally, it has also been found that some of the benefits of the present invention are not affected by the presence of ZDDP as compared to what is observed for non-ether based lubricant compositions. Surprisingly, some of the benefits of the present invention are even enhanced by the presence of ZDDP in the lubricant composition. For example, in CEC-L-109 tests involving non-ether based compositions comprising aminic and/or phenolic antioxidants, it has been observed that the presence of ZDDP exacerbates oxidative thickening. In contrast, the presence of ZDDP together with aminic and phenolic antioxidants in the ether-based compositions of the present invention unexpectedly results in high oxidative stability and oxidative thickening resistance in the CEC-L-109 test, which indicates synergy between the ether base stock and the ZDDP and antioxidant components in the lubricant composition. Thus, an additional benefit of the present invention is that greater amounts of ZDDP can be used with the ether compositions of the present invention without significantly affecting the oxidative stability of the compositions, thereby achieving the full antiwear benefits of ZDDP.

Still further, it has also been found that some of the benefits of the present invention are not affected by the presence of significant amounts of boron or magnesium in the lubricant composition, for example in the form of a borated dispersant or magnesium detergent, as is observed in comparison to the case for non-ether based lubricant compositions. In the CEC-L-109 test for non-ether based lubricant compositions, the presence of a borated dispersant and/or other boron containing additives or magnesium resulted in a substantial increase in the percent change in kinematic viscosity at 100 ℃. In contrast, the presence of boron and/or magnesium in the ether-based composition according to the invention is well tolerated without a significant increase in oxidative thickening. This is particularly beneficial because increasing boron in the lubricant composition results in increased elastomer compatibility and reduced corrosion of the lubricated surface, while magnesium reduces the occurrence of low speed pre-ignition.

In some embodiments, the lubricant compositions of the present invention may comprise both aminic antioxidants and phenolic antioxidants.

In some embodiments, the lubricant compositions of the present invention may comprise either an aminic antioxidant or a phenolic antioxidant, and not both.

The aminic antioxidants and/or phenolic antioxidants present in the compositions of the present invention are not particularly limited, provided that they are suitable for use in lubricant compositions intended for use in internal combustion engines, such as the internal combustion engines of motor vehicles.

In some embodiments, the phenolic antioxidant is selected from alkylated monophenols, alkylated hydroquinones, hydroxylated thiodiphenyl ethers, alkylene bisphenols, amido phenols and sulfurized alkylphenols, and alkali metal and alkaline earth metal salts thereof. In a preferred embodiment, the phenolic antioxidant is selected from the group consisting of 2-tert-butyl-4-heptylphenol, 2-tert-butyl-4-octylphenol, 2-tert-butyl-4-dodecylphenol, 2, 6-di-tert-butyl-4-methylphenol, 2, 6-di-tert-butyl-4-heptylphenol, 2, 6-di-tert-butyl-4-dodecylphenol, 2-methyl-6-tert-butyl-4-heptylphenol, 2-methyl-6-tert-butyl-4-dodecylphenol, 4 '-methylenebis (2, 6-di-tert-butylphenol), 2' -bis (4-heptyl-6-tert-butylphenol), 2 '-bis (4-octyl-6-tert-butylphenol), 2' -bis (4-dodecyl-6-tert-butylphenol), 4 '-bis (2, 6-di-tert-butylphenol) and 4,4' -methylene-bis (2, 6-di-tert-butylphenol) and derivatives thereof.

In some embodiments, the aminic antioxidant is selected from alkylated and non-alkylated aromatic amines, alkylated diphenylamines, N-alkylated phenylenediamines, phenyl-alpha-naphthylamines, and alkylated phenyl-alpha-naphthylamines. In a preferred embodiment, the aminic antioxidant is selected from the group consisting of p, p-dioctylaniline, tert-octylphenyl-alpha-naphthylamine, p-octylphenyl-alpha-naphthylamine, monooctyldiphenylamine, N-di (2-naphthyl) -p-phenylenediamine, phenyl-1-naphthylamine, phenyl-2-naphthylamine, alkylphenyl-1-naphthylamine and alkylphenyl-2-naphthylamine, and derivatives thereof.

The lubricant composition may also contain other antioxidants that are not aminic or phenolic in nature. For example, the lubricant composition of the present invention may additionally comprise an antioxidant selected from the group consisting of: hydroxylated thiodiphenyl ethers, thiopropionates, metal dithiocarbamates, 1,3, 4-dimercaptothiadiazoles and derivatives, oil-soluble copper compounds (e.g. copper dihydrocarbyl or copper thiophosphates; copper salts of synthetic or natural carboxylic acids, e.g. C ₈ To C ₁₈ Fatty acids, unsaturated acids or branched carboxylic acids, said copper salts being derived, for example, from basic, neutral or acidic Cu (I) and/or Cu (II) salts of alkenyl succinic acids or anhydrides, alkaline earth metal salts of alkylphenyl thioesters, suitably containing C ₅ To C ₁₂ Alkyl side chains), tert-octylphenyl barium sulfide, phosphosulfurized or sulfurized hydrocarbons, oil soluble phenates, oil soluble sulfurized phenates, phosphosulfurized hydrocarbons, sulfurized hydrocarbons, phosphorus esters, low sulfur peroxide decomposers, and the like.

As will be appreciated, it is preferred that the non-aminic and non-phenolic antioxidants be used in minimum amounts in their presence. In some embodiments, the total amount of non-aminic and non-phenolic antioxidants in the lubricant composition is no more than 1.0%, no more than 0.75%, or no more than 0.5% by weight of the lubricant composition. In some embodiments, the antioxidant present in the lubricant composition consists of, or consists essentially of, an aminic antioxidant and/or a phenolic antioxidant.

In addition to the antioxidant, the lubricant composition may also contain other lubricant additives. Additional lubricant additives will typically be present in the lubricant composition in an amount of from about 2wt.% to about 40 wt.%, for example from about 3wt.% to about 30 wt.%.

Suitable additional lubricant additives include detergents (including metallic and non-metallic detergents), friction modifiers, viscosity modifiers, dispersants (including metallic and non-metallic dispersants), dispersant viscosity modifiers, viscosity index improvers, pour point depressants, antiwear additives, rust inhibitors, corrosion inhibitors, antioxidants (also sometimes referred to as oxidation inhibitors), antifoamants (also sometimes referred to as antifoamants), seal swell agents (also sometimes referred to as seal compatibilisers), extreme pressure additives (including metallic, non-metallic, phosphorus-, non-phosphorus-, sulfur-and non-sulfur-containing extreme pressure additives), surfactants, demulsifiers, anti-seizing agents (anti-sessilisation agents), wax modifiers, lubricants, anti-staining agents, chromophoric agents, metal deactivators, and mixtures of two or more thereof.

In some embodiments, the lubricant composition comprises a detergent. Examples of detergents include ashless detergents (i.e., metal-free detergents) and metal-containing detergents. Suitable non-metallic detergents are described, for example, in US7,622,431. Metal-containing detergents comprise at least one metal salt of at least one organic acid, which is known as a soap or a surfactant. Suitable organic acids include, for example, sulfonic acids, phenols (suitably sulfurized and including, for example, phenols having more than one hydroxyl group, phenols having a fused aromatic ring, modified phenols, such as alkylene bridged phenols, and Mannich base-condensed phenols and salicin-type phenols, such as produced by the reaction of phenol with an aldehyde under basic conditions), and sulfurized derivatives thereof, and carboxylic acids including, for example, aromatic carboxylic acids (e.g., hydrocarbyl-substituted salicylic acids and derivatives thereof, such as hydrocarbyl-substituted salicylic acids and sulfurized derivatives thereof).

Advantageously, magnesium detergents may also be used in the lubricant compositions of the present invention without negatively affecting oxidation stability. In some embodiments, the amount of magnesium contained in the lubricant composition is from 0.025wt.% to 0.5wt.%, preferably from 0.05wt.% to 0.4wt.%, more preferably from 0.08wt.% to 0.35wt.%, even more preferably from 0.1wt.% to 0.25wt.%. This level of elemental magnesium may result from the use of magnesium detergents and/or other magnesium-containing additives or other forms.

In some embodiments, the lubricant composition comprises a friction modifier. Suitable friction modifiers include, for example, ash-producing additives and ashless additives. Examples of suitable friction modifiers include fatty acid derivatives, including, for example, fatty acid esters, amides, amines, and ethoxylated amines. Examples of suitable ester friction modifiers include esters of glycerol such as monooleate, dioleate and trioleate, monopalmitate and monomyristate. A particularly suitable fatty acid ester friction modifier is glycerol monooleate. Examples of suitable friction modifiers also include molybdenum compounds such as organo-molybdenum compounds, molybdenum dialkyldithiocarbamates, molybdenum dialkylthiophosphates, molybdenum disulfide, trimolybdenum dialkyldithiocarbamates, sulfur-free molybdenum compounds, and the like. Suitable molybdenum-containing compounds are described, for example, in EP1533362Al, for example in paragraphs [0101] to [0117 ].

In some embodiments, the lubricant composition comprises a dispersant. Examples of suitable ashless dispersants include oil soluble salts, esters, amino esters, amides, imides and oxazolines of long chain hydrocarbon substituted monocarboxylic and polycarboxylic acids or anhydrides thereof; thiocarboxylate derivatives of long chain hydrocarbons; long chain aliphatic hydrocarbons containing a polyamine moiety attached directly thereto; a Mannich condensation product formed by condensing a long chain substituted phenol with formaldehyde and a polyalkylene polyamine; koch (Koch) reaction products, and the like. Particularly preferred dispersants for use in the present invention are long chain aliphatic hydrocarbons containing polyamine moieties attached directly thereto, such as polyisobutylene succinic anhydride-polyamine (PIBSA-PAM).

Advantageously, boronated dispersants may also be used in the lubricant compositions of the present invention without negatively impacting oxidative stability. In some embodiments, the lubricant composition may contain the following amounts of boron: 0.005wt.% to 0.05wt.%, preferably 0.0075wt.% to 0.035wt.%. This level of elemental boron may be obtained from borated dispersants and/or boron-containing anti-wear additives or other forms of use.

In some embodiments, the lubricant composition comprises a dispersant viscosity modifier. Examples of suitable dispersant viscosity modifiers and methods for making them are described in WO99/21902, WO2003/099890 and WO 2006/099250.

In some embodiments, the lubricant composition comprises a viscosity index improver. Examples of suitable viscosity modifiers include high molecular weight hydrocarbon polymers (e.g., polyisobutylene, copolymers of ethylene and propylene and higher alpha-olefins); polyesters (e.g., polymethacrylates); hydrogenated poly (styrene-co-butadiene or isoprene) polymers and modifications (e.g., star polymers); and esterified poly (styrene-co-maleic anhydride) polymers. The oil-soluble viscosity modifying polymer typically exhibits a number average molecular weight of at least about 15,000 to about 1,000,000, for example about 20,000 to about 600,000, as determined by gel permeation chromatography or light scattering methods.

In some embodiments, the lubricant composition comprises a pour point depressant. Examples of suitable pour point depressants include fumaric acid C ₈ To C ₁₈ Dialkyl ester/vinyl acetate copolymers, methacrylates, polyacrylates, polyacrylamides, polymethacrylates, polyalkylmethacrylates, vinyl fumarates, styrene esters, condensation products of halogenated paraffins with aromatics, vinyl carboxylate polymers; dialkyl fumarates, terpolymers of vinyl esters of fatty acids and allyl vinyl ether, waxy naphthalenes, and the like.

In some embodiments, the lubricant composition comprises at least one anti-wear additive. Examples of suitable antiwear additives include phosphorus-free additives such as sulfurized olefins. Examples of suitable anti-wear additives also include phosphorus-containing anti-wear additives. Examples of suitable ashless, phosphorus-containing, anti-wear additives include trilaurylphite and triphenylthiophosphate and those disclosed in paragraph [0036] of US 2005/0198894. Examples of suitable ash-forming phosphorus-containing anti-wear additives include dihydrocarbyl dithiophosphate metal salts. Examples of suitable metals for dihydrocarbyl dithiophosphate metal salts include alkali and alkaline earth metals, aluminum, lead, tin, molybdenum, manganese, nickel, copper and zinc. A particularly suitable metal dihydrocarbyl dithiophosphate is Zinc Dihydrocarbyl Dithiophosphate (ZDDP).

In some embodiments, the amount of phosphorus contained in the lubricant composition is less than 0.5wt.%, preferably 0.001 to 0.3wt.%, more preferably 0.025 to 0.2wt.%, and even more preferably 0.04 to 0.12wt.%, based on the total weight of the lubricant composition.

The use of ZDDP in the compositions of the present invention is particularly beneficial to the overall properties of the lubricant composition, especially from an anti-wear standpoint, since ZDDP is particularly well tolerated in terms of oxidative stability of the lubricant composition of the present invention and also appears to impart a synergistic effect when used in combination with ether-based basestocks and antioxidants. Thus, in some embodiments, the amount of metal dihydrocarbyl dithiophosphate (preferably in the form of Zinc Dihydrocarbyl Dithiophosphate (ZDDP)) in the lubricant composition is from 0.01wt.% to 10.0wt.%, preferably from 0.1wt.% to 5wt.%, more preferably from 0.2wt.% to 2.5wt.%, and even more preferably from 0.3wt.% to 1.0wt.%.

In some embodiments, the lubricant composition comprises a rust inhibitor. Examples of suitable rust inhibitors include nonionic polyoxyalkylene polyols and esters thereof, polyoxyalkylene phenols, polyoxyalkylene polyols, anionic alkyl sulfonic acids, zinc dithiophosphates, metal phenolates, basic metal sulfonates, fatty acids, and amines.

In some embodiments, the lubricant composition comprises a corrosion inhibitor. Examples of suitable corrosion inhibitors include phosphosulfurized hydrocarbons and products obtained by reacting a phosphosulfurized hydrocarbon with an alkaline earth metal oxide or hydroxide, nonionic polyoxyalkylene polyols and esters thereof, polyoxyalkylene phenols, thiadiazoles, triazoles, and anionic alkyl sulfonic acids. Examples of suitable epoxidized ester corrosion inhibitors are described in US 2006/0090393.

In some embodiments, the lubricant composition comprises an anti-foaming agent. Examples of suitable defoamers include silicones, organic polymers, siloxanes (including polysiloxanes and (poly) dimethylsiloxanes, phenylmethylsiloxanes), acrylates, and the like.

In some embodiments, the lubricant composition comprises a seal swell agent. Examples of suitable seal swell agents include long chain organic acids, organic phosphates, aromatic esters, aromatic hydrocarbons, esters (e.g., butyl benzyl phthalate), and polybutenyl succinic anhydride (polybutenylsuccinamide).

The lubricant composition may comprise lubricant additives in the amounts shown in table 3.

TABLE 3

The lubricant composition may have a kinematic viscosity at 40 ℃ of less than about 60cSt, such as less than about 55cSt or less than about 50 cSt. The lubricant composition can have a kinematic viscosity at 100 ℃ of less than about 12cSt, such as less than about 10cSt or less than about 9.5 cSt. The lubricant composition may have a viscosity index greater than about 100, such as greater than about 110 or greater than about 120. Kinematic viscosity at 40 ℃ and kinematic viscosity at 100 ℃ can be measured according to astm d 445. The viscosity index can be calculated according to astm d 2270.

The lubricant composition may have a Noak volatility of less than about 25wt.%, such as less than about 15 wt.% or less than about 10 wt.%. Noak volatility can be measured according to CEC-L-40-A-93.

Lubricant compositions at 150 ℃ and 10 ⁶ s ^-1 May have a viscosity of no greater than 3cP, such as no greater than 2.8cP, at shear rates of (a). Such high temperature high shear viscosity can be measured according to CEC-L-36-A-90.

The lubricant composition may have at least one of:

oxidation stability performance as indicated by an increase in absolute viscosity at 40 ℃ of no more than 45cSt, e.g., no more than 35cSt or no more than 25cSt, as tested by CEC-L-088-02; a fuel economy performance of at least 2.5%, such as at least 3%, as tested by CEC-L-054-96; piston cleanliness performance as indicated by a CEC-L-088-02 test as assessed by a composite piston of at least 8.5, e.g., 9; and oxidation stability performance as indicated by an increase in kinematic viscosity at 100 ℃ of less than 200% (preferably less than 150%) at 216 hours and/or less than 200% (preferably less than 150%) at 168 hours, as tested by CEC-L-109-14.

The lubricant composition may have a cold crankcase simulator performance at-30 ℃ of less than about 3000, such as less than about 2800 or less than about 2750, as measured, for example, according to astm d 5293.

Preferred lubricant compositions meet the requirements set forth in SAEJ 300.

The lubricant composition may be used in a method of lubricating a surface.

Suitable surfaces include, for example, those used in the drivetrain (e.g., drive train and gearbox) of vehicles (including, for example, passenger and heavy vehicles); and internal combustion engines (e.g., crankcases for internal combustion engines). Suitable surfaces also include those in turbine bearings (e.g., water turbine bearings).

Suitable internal combustion engines include, for example, engines used in automotive applications, engines used in marine applications, and engines used in land-based power plants. The lubricant composition is particularly suitable for use in an automotive internal combustion engine.

The lubricant compositions may be used to improve fuel economy and/or piston cleanliness performance of an internal combustion engine and/or vehicle (e.g., a motor vehicle associated with the internal combustion engine). Accordingly, a method of improving fuel economy and/or piston cleanliness performance of an internal combustion engine and/or vehicle (e.g., a motor vehicle associated with an internal combustion engine) is provided, comprising the step of providing or supplying at least one of the lubricant compositions to the engine and/or vehicle.

The invention will now be described with reference to the figures and examples, which are non-limiting in nature.

Examples

EXAMPLE 1 Properties of Ether-based basestocks

A guerbet (alcohol) -derived base stock GE3 of formula (1) was prepared, the structure of which is shown in table 4.

TABLE 4

The base stock was tested for the following properties:

the kinematic viscosity at 100 ℃ (KV 100) and at 40 ℃ (KV 40) were tested according to ASTM D7279.

The Viscosity Index (VI) was calculated according to astm d 2270.

Pour point was determined according to astm d 7346.

Differential Scanning Calorimetry (DSC) oxidation onset temperatures were tested using a method based on astm e2009 (method B). According to the method, a base stock is heated from 50 ℃ to 300 ℃ at a rate of 50 ℃/minute under a pressure of 500psi in an aluminum SFI pan. The temperature at which the temperature rise was observed was recorded.

Noak volatility was measured using a method based on IP393 and believed to be similar to CEC-L-40-A-93. According to this method, reference oils with known Noak volatility are heated from 40 ℃ to 550 ℃ to determine the temperature at which the weight loss of Noak volatility of each reference oil is reached. The base stock was subjected to the same procedure as the reference oil. The Noakg weight of the base stock can be determined based on the results obtained from the reference oil.

The results of the tests are summarized in table 5 together with the results obtained from conventional base stocks (Yubase 4: group III base stocks).

TABLE 5

It can be seen that the guerbet (alcohol) derived base stock ethers have lower volatility, lower pour point and lower kinematic viscosity than conventional base oils.

Example 2: properties of Lubricant compositions containing Ether-based basestocks

The guerbet (alcohol) derived ether base stock GE3 is blended with conventional base oil additives (additive a: a commercially available additive package which provides a representative dispersant level of high performance engine oils of between 7 and 10wt%, based on the total weight of the lubricant composition; additive B: a cold flow improver; additive C: an oxidation inhibitor; and additive D: a viscosity index improver) and conventional base oils (Yubase 4: group III base oils; and Yubase6: group III base oils) to form a lubricant blend. A baseline blend was also prepared. Yubase4 was chosen as the major component of the baseline blend because it exhibited KV100 similar to the guerbet (alcohol) derived ether base stock GE 3. This baseline blend is believed to be a strict baseline for comparison, as it is a 5W-30 formulation that meets certain specifications (ACEAA 5/B5, API-SN/GF-4). Details of the blend compositions are shown in table 6 (in wt%).

TABLE 6

No miscibility problems were encountered during the preparation of the blend compositions.

The blend compositions were tested to see if the advantageous properties of the base stock would be reflected in a fully formulated lubricant composition. The following properties were tested:

kinematic viscosity at 100 ℃ (KV 100) and at 40 ℃ (KV 40) were tested according to astm d445 (part of SAEJ 300).

The Viscosity Index (VI) was calculated according to astm d 2270.

Cold start simulator (CCS) analysis was performed at-30 ℃ according to astm d5293 (part of SAEJ 300).

High Temperature High Shear (HTHS) analysis was performed according to CEC-L-36-A-90.

Total Base Number (TBN) was determined according to ASTM D2896.

Noak volatility was tested according to CEC-L-40-A-93.

The sulfated ash content was measured according to IP 163.

The test results are summarized in table 7.

TABLE 7

It can be seen that the properties of the guerbet (alcohol) -derived base stock are also exhibited in the blend composition. In particular, beneficial viscosity, volatility and cold flow properties were observed. The guerbet (alcohol) -derived base stocks also exhibited HTHS measurements, TBN, and sulfated ash content similar to the baseline blend.

Example 3: CEC-L-85-99 assay

Blend compositions comprising a guerbet (alcohol) derived base stock (GE 3), a group III base stock (Yubase 4) or a group IV base stock (PAO 4) along with varying amounts of aminic oxidants (diphenylamine) and/or phenolic oxidants (substituted phenols) were subjected to a CEC-L-85-99 test which measures the DSC oxidation onset temperature and DSC oxidation induction time of the blends tested. The results obtained from the CEC-L-85-99 test are shown in Table 8 (composition data is shown in weight%).

TABLE 8

The results in table 8 demonstrate that when either a phenolic antioxidant (blend K) or an aminic antioxidant (blend L) is present in the ether blend, both the oxidation onset temperature and the oxidation induction time are increased, indicating increased oxidative stability (compared to blend J). In addition, when both aminic and phenolic antioxidants were added (blend M), a large increase in oxidation onset temperature and oxidation induction time was observed. In particular, when comparing non-ether blends (blends B to D and F to H), it is clear that the oxidation onset temperature and oxidation induction time are only moderately increased when both aminic and phenolic antioxidants are present (blends D and H) compared to when they are present alone (blends B, C, F and G). This indicates that there is a synergistic effect associated with ether-based basestocks with aminic and phenolic antioxidants, which is not observed with non-ether basestocks. This effect can be readily seen when comparing test blends (blends D, H and M) comprising both aminic and phenolic antioxidants present, with movement to the ether-based system (blend M) resulting in an increase in oxidation induction time of more than 25% over the systems based on classes III and IV (blends D and H).

Example 4: CEC-L-85-99 test-fully formulated lubricant compositions

A fully formulated lubricant composition containing a guerbet (alcohol) derived base stock (GE 3) and a group III base stock (Yubase 4) along with varying amounts of aminic and/or phenolic oxidizers, as well as other lubricant additives including (non-boronated) dispersants, detergents, viscosity Index Modifiers (VIM) and secondary ZDDP, was subjected to CEC-L-85-99 testing. The results obtained from the CEC-L-85-99 test are shown in Table 9 (composition data is shown in weight%).

The results in table 9 demonstrate that as the levels of phenolic and aminic antioxidants in the ether-based composition are increased, both the oxidation onset temperature and the oxidation induction time are increased, indicating increased oxidative stability. In addition, a large increase in oxidation onset temperature and oxidation induction time was observed when both the aminic and phenolic antioxidants were added (compositions 12 and 16), each at a level of 0.5wt.%, compared to when one of the aminic or phenolic antioxidants was present at a lower concentration of 0.1wt.% (compositions 10, 11, 14 and 15).

In particular, in addition to the aminic or phenolic antioxidants, the presence of ZDDP surprisingly also confers a large increase in oxidative stability, as shown by the corresponding increase in oxidation onset temperature and oxidation induction time (compositions 13 to 16 compared to compositions 9 to 12). Furthermore, this effect is particularly pronounced in the case where equal amounts (0.5 wt.%) of aminic and phenolic antioxidants are present in the ether-based composition (composition 16). However, this significant effect was not observed in the corresponding non-ether based system (composition 8), indicating that there is a synergistic effect associated with the combination of ether base stocks along with aminic and phenolic antioxidants and ZDDP. Thus, the presence of ZDDP provides a further improvement in the oxidative stability of the compositions of the present invention while also resulting in improved antiwear properties of the lubricant compositions.

Example 5: CEC-L-109 assay

CEC-L-109 testing was performed on fully formulated lubricant compositions containing guerbet (alcohol) derived base stocks (GE 3) and group III base stocks (Yubase 4) along with varying amounts of aminic and/or phenolic oxidizers, as well as other lubricant additives including (non-boronated) dispersants, boronated dispersants, detergents, viscosity Modifiers (VM), and secondary ZDDP). The CEC-L-109 test is a high temperature oxidation test designed to determine the oxidation stability of an engine lubricant via measuring the percent increase in kinematic viscosity at 100 ℃ ("KV 100% change"), with a lower percent change indicating a higher oxidation stability. The results obtained from the CEC-L-109 test are shown in Table 10 (composition data is shown in weight%).

The CEC-L-109 test results (in the form of an average percent increase in kinematic viscosity at 100 ℃ from repeated runs) illustrate the benefit of increasing total antioxidant concentration (compare the results for composition b with the results for composition a) and the negative impact of the presence of ZDDP on the oxidative stability of the non-ether based lubricant compositions in this test (compare the results for compositions a and b with the results for compositions c and d).

However, it is apparent from the results for composition f that the oxidative stability of the ether-based composition as measured by the CEC-L-109 test is not significantly affected by the presence of ZDDP, where this is clearly not the case for the corresponding non-ether-based composition e, which has the same ZDDP and antioxidant levels as composition f (40.7% change for composition f vs 227% change for composition e). These results indicate synergy between the ether basestocks and the ZDDP and antioxidant components in the lubricant compositions. Thus, this means that greater amounts of ZDDP can be used with the ether compositions of the present invention without significantly affecting the oxidative stability of the compositions, such that the full antiwear benefits of ZDDP can be achieved.

The presence of 6wt.% boronated dispersant for lubricant compositions g and h provided the lubricant composition with about 0.021wt.% boron (on an elemental basis). The presence of the borated dispersant and the associated boron caused a significant increase in the percent change in kinematic viscosity at 100 ℃ of the non-ether based composition g (too viscous to measure). In contrast, the presence of the borated dispersant in the ether-based composition h was well tolerated with only a modest average percent increase in kinematic viscosity at 100 ℃ (84.4%). These results demonstrate that despite the increased boron content, the oxidation stability of the ether compositions of the present invention is substantially maintained. This is particularly beneficial because increasing boron in the lubricant composition results in increased elastomer compatibility and reduced corrosion.

For lubricant compositions i and j, the presence of 0.86wt.% magnesium-containing detergent provides about 0.072wt.% magnesium (on an elemental basis) for the lubricant compositions. The presence of magnesium-containing detergents resulted in a large increase in the percent change in kinematic viscosity at 100 ℃ of the non-ether based composition i (too viscous to measure). In contrast, the presence of magnesium-containing detergents in ether-based composition j was well tolerated with only a modest average percent increase in kinematic viscosity at 100 ℃ (76.1%). These results demonstrate that the oxidative stability of the ether compositions of the present invention is substantially maintained despite the increased magnesium content. This is particularly beneficial because increasing the magnesium-containing detergent in the lubricant composition provides a reduced level of sulphated ash for the same total base number (acid neutralising ability) compared to a calcium-containing detergent.

The effect of the presence of ZDDP and/or boronated dispersant in the compositions of the present invention (compositions f and h) compared to conventional non-ether based compositions (compositions e and g) as discussed above is also illustrated in figure 1.

The results in the above examples demonstrate the benefit of ether base stocks along with aminic and/or phenolic antioxidants for improved oxidative stability, as well as additional benefits resulting from cooperativity with ZDDP. These results demonstrate that lower amounts of aminic and/or phenolic antioxidants can be used in lubricant compositions comprising ether basestocks according to the present invention and that similar or better oxidative stability is achieved compared to conventional non-ether based lubricant compositions. Reducing amine antioxidants in lubricant compositions for internal combustion engines has particular benefits in reducing turbocharger deposits as well as reducing copper corrosion and increasing elastomer compatibility. At the same time, the reduction of phenolic antioxidants results in an improvement in the environmental toxicity of the lubricant composition.

The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Rather, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as "40mm" is intended to mean "about 40mm".

Each document cited herein (including any cross-referenced or related patent or application) is hereby incorporated by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it teaches, suggests or discloses any such invention alone or in any combination with any other reference or references. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the term in a document incorporated by reference, the meaning or definition assigned to the term in this document shall govern.

While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope and spirit of this invention.

Claims

1. A lubricant composition for an internal combustion engine comprising a base oil of lubricating viscosity, wherein the base oil comprises an ether base stock of formula (a):

wherein: r _a And R _b Are aliphatic hydrocarbon radicals, which are identical or different; wherein R is _a And R _b Is a branched alkyl, alkoxy-substituted alkyl, or cycloalkyl-substituted alkyl;

Wherein the total combined amount of aminic antioxidant and phenolic antioxidant in the lubricant composition does not exceed 4.0 wt.% of the lubricant composition.

2. The lubricant composition of claim 1, wherein R _a And R _b Independently selected from alkyl, alkoxy substituted alkyl or cycloalkyl substituted alkyl, with the proviso that when R is _a And R _b When both are alkyl, R _a And R _b At least one of which is a branched alkyl group.

3. The lubricant composition of claim 1, wherein R _a Ratio R _b Containing more carbon atoms.

4. The lubricant composition of any one of claims 1 to 3 wherein R _a Containing 12 to 30 carbon atoms, and/or R _b Containing 2 to 20 carbon atoms.

5. The lubricant composition of any one of claims 1 through 3, wherein the ether basestock has formula (1):

R ₃ 、R ₄ and R ₅ Is H or alkyl;

R ₆ is alkyl or

R ₉ is H or alkyl;

x is alkylene or absent; and

p is 0, 1, 2 or 3; and is

m and n are 0, 1, 2 or 3, wherein when R ₄ And R ₅ When it is H, m is 0.

6. The lubricant composition of claim 5, wherein R ₁ And R ₂ Is C _1-15 Alkyl radicals, or together with the carbon atom to which they are attached, C _5-30 A cycloalkyl group; and/or

Wherein R is ₃ 、R ₄ And R ₅ Is H or C _1-15 An alkyl group.

7. The lubricant composition of claim 5 wherein m and n are 0, 1 or 2.

8. The lubricant composition of any one of claims 1 to 3 and 6 to 7, wherein the ether basestock has formula (2):

R ₃ and R ₅ Is H or alkyl;

R ₆ is alkyl or

R ₉ is H or alkyl;

x is alkylene or absent; and

p is 0, 1, 2 or 3; and is

n is 0, 1, 2 or 3.

9. The lubricant composition of any one of claims 1 through 3 and 6 through 7 wherein the ether base stock contains a total of 20 to 50 carbon atoms.

10. The lubricant composition of any one of claims 1 through 3 and 6 through 7 wherein the ether base stock is prepared from a biologically derived feedstock.

11. The lubricant composition of any one of claims 1 to 3 and 6 to 7 wherein said base oil of said lubricant composition comprises greater than 10 weight percent of said ether base stock and/or wherein said lubricant composition comprises greater than 50 weight percent of said base oil.

12. The lubricant composition of claim 11, wherein the base oil of the lubricant composition further comprises a base stock selected from the group consisting of: group I basestocks, group II basestocks, group III basestocks, group IV basestocks, and group V basestocks, and mixtures thereof.

13. The lubricant composition of any one of claims 1 to 3, 6 to 7, and 12, wherein the lubricant composition has at least one of:

a kinematic viscosity at 40 ℃ of less than 60 cSt;

a kinematic viscosity at 100 ℃ of less than 12 cSt;

a viscosity index greater than 100;

at 150 ℃ and 10 ⁶ s ^-1 A viscosity of no greater than 3cP at shear rate of (a); and

a Noak volatility of less than 25 wt%.

14. The lubricant composition of any one of claims 1 to 3, 6 to 7, and 12, wherein the lubricant composition has at least one of:

oxidative stability performance as indicated by an increase in absolute viscosity of no more than 45cSt at 40 ℃ as measured by CEC-L-088-02; oxidative stability performance as indicated by an increase in kinematic viscosity at 100 ℃ of less than 200% over 168 hours as measured by CEC-L-109-14;

CEC-L-054-96 tests show that the fuel economy performance is at least 2.5 percent; and

the piston cleanliness performance as indicated by the composite piston was evaluated to be at least 8.5 by the CEC-L-088-02 test.

15. The lubricant composition of any one of claims 1 through 3, 6 through 7, and 12 wherein the total combined amount of aminic and phenolic antioxidants in the lubricant composition does not exceed 3.0% by weight of the lubricant composition.

16. The lubricant composition of any one of claims 1 to 3, 6 to 7, and 12 wherein the total combined amount of aminic antioxidant and phenolic antioxidant in the lubricant composition is at least 0.25% by weight of the lubricant composition.

17. The lubricant composition of any one of claims 1 to 3, 6 to 7, and 12 wherein the total amount of non-aminic and non-phenolic antioxidants in the lubricant composition does not exceed 1.0% by weight of the lubricant composition.

18. The lubricant composition of any one of claims 1 through 3, 6 through 7, and 12, wherein the lubricant composition comprises an aminic antioxidant or a phenolic antioxidant, but does not comprise both an aminic antioxidant and a phenolic antioxidant.

19. The lubricant composition of any one of claims 1 through 3, 6 through 7, and 12 wherein said at least one phenolic antioxidant is selected from the group consisting of alkylated monophenols, alkylated hydroquinones, hydroxylated thiodiphenyl ethers, alkylene bisphenols, amido phenols and sulfurized alkylphenols, and alkali and alkaline earth metal salts thereof.

20. The lubricant composition of any one of claims 1 through 3, 6 through 7, and 12, wherein the at least one phenolic antioxidant is selected from the group consisting of 2-tert-butyl-4-heptylphenol, 2-tert-butyl-4-octylphenol, 2-tert-butyl-4-dodecylphenol, 2, 6-di-tert-butyl-4-methylphenol, 2, 6-di-tert-butyl-4-heptylphenol, 2, 6-di-tert-butyl-4-dodecylphenol, 2-methyl-6-tert-butyl-4-heptylphenol, 2-methyl-6-tert-butyl-4-dodecylphenol, 4' -methylenebis (2, 6-di-tert-butylphenol), 2' -bis (4-heptyl-6-tert-butylphenol), 2' -bis (4-octyl-6-tert-butylphenol), 2' -bis (4-dodecyl-6-tert-butylphenol), 4' -bis (2, 6-di-tert-butylphenol), and derivatives thereof.

21. The lubricant composition of any one of claims 1 to 3, 6 to 7, and 12, wherein said at least one aminic antioxidant is selected from alkylated and non-alkylated aromatic amines.

22. The lubricant composition of any one of claims 1 to 3, 6 to 7, and 12 wherein the at least one aminic antioxidant is selected from the group consisting of p, p-dioctylaniline, monooctyldiphenylamine, N-bis (2-naphthyl) -p-phenylenediamine, phenyl-1-naphthylamine, phenyl-2-naphthylamine, alkylphenyl-1-naphthylamine, alkylphenyl-2-naphthylamine, and derivatives thereof.

23. The lubricant composition of any one of claims 1 through 3, 6 through 7, and 12, wherein the amount of phosphorus contained in the lubricant composition is less than 0.5wt.%, based on the total weight of the lubricant composition.

24. The lubricant composition of any one of claims 1 through 3, 6 through 7, and 12, wherein the amount of boron contained in the lubricant composition is 0.005wt.% to 0.05wt.%.

25. The lubricant composition of any one of claims 1 through 3, 6 through 7, and 12, wherein the amount of magnesium contained in the lubricant composition is from 0.025wt.% to 0.5wt.%.

26. The lubricant composition of any one of claims 1 to 3, 6 to 7, and 12, wherein the lubricant composition comprises one or more dihydrocarbyl dithiophosphate metal salts in an amount of 0.01wt.% to 10.0wt.%.

27. A method of preparing a lubricant composition, the method comprising providing a base oil as defined in any one of claims 1 to 12, and blending the base oil with at least one aminic antioxidant and/or at least one phenolic antioxidant such that the total combined amount of aminic antioxidant and phenolic antioxidant in the lubricant composition does not exceed 4.0% by weight of the lubricant composition, and optionally further blending one or more additional lubricant additives, so as to prepare the lubricant composition.

28. A method of lubricating a surface, the method comprising supplying to the surface a lubricant composition as defined in any one of claims 1 to 26.

29. Use of a lubricant composition according to any one of claims 1 to 26 for lubricating a surface.

30. Use of an ether basestock as defined in any of claims 1 to 12 for reducing the total amount of antioxidant additives required in a lubricant composition comprising at least one aminic antioxidant and/or at least one phenolic antioxidant in order for the lubricant composition to achieve a specific level of oxidative stability performance.

31. A method of improving fuel economy performance and/or piston cleanliness performance of an engine and/or vehicle comprising the step of providing the engine and/or vehicle with a lubricant composition according to any one of claims 1 to 26.

32. Use of a lubricant composition according to any one of claims 1 to 26 to improve fuel economy performance and/or piston cleanliness performance of an engine and/or vehicle.