US20080090743A1

US20080090743A1 - Compounds and methods of making the compounds

Info

Publication number: US20080090743A1
Application number: US11/550,242
Authority: US
Inventors: Naresh C. Mathur
Original assignee: Afton Chemical Corp
Current assignee: Afton Chemical Corp
Priority date: 2006-10-17
Filing date: 2006-10-17
Publication date: 2008-04-17
Also published as: DE102007047275A1; FR2907782A1; GB2443059A; GB0718972D0

Abstract

The present application is directed to compounds that are the reaction product of (i) a hydrocarbyl phenol, (ii) a hindered phenol; (iii) an diaryldiamine and (iv) an aldehyde. Methods of making and using the compounds of the present application are disclosed.

Description

DESCRIPTION OF THE DISCLOSURE

1. Field of the Disclosure
The present application is directed to novel antioxidants, processes for making the antioxidants, and compositions that comprise the antioxidants.
2. Background of the Disclosure
Lubricating oils as used in the internal combustion engines and transmissions of automobiles or trucks are subjected to a demanding environment during use. This environment results in the oil suffering oxidation which is catalyzed by the presence of impurities in the oil, such as iron compounds, and is also promoted by the elevated temperatures of the oil during use.
The oxidation of lubricating oils during use is often controlled to some extend by the use of antioxidant additives. Antioxidant additives can extend the useful life of the lubricating oil by, for example, reducing or preventing unacceptable viscosity increases.
A combination of antioxidants is often employed in lubricants. One such combination includes both hindered phenol compounds and alkylated diphenylamines as antioxidants. These antioxidants are believed to work synergistically by converting relatively reactive alkoxy and/or alkyl radicals to less reactive phenoxy radicals.

SUMMARY OF THE DISCLOSURE

In accordance with the disclosure, and aspect of the present application is directed to a compound that is the reaction product of (i) a hydrocarbyl phenol, (ii) a hindered phenol, (iii) an diaryldiamine and (iv) an aldehyde.
Another aspect of the present application is directed to a compound of formula V,
wherein R¹and R²are independently chosen from hydrogen and hydrocarbyl groups, with the proviso that at least one of R¹and R²is a hydrocarbyl group; R³and R⁴are independently chosen from hydrogen and a linear or branched C₁to C₁₂alkyl group, with the proviso that at least one of R³and R⁴is a branched C₃to C₁₂alkyl group; ′R⁵is a secondary amine substituent; R⁶and R⁷are independently chosen from hydrogen, C₁to C₁₈linear, branched or cyclic alkyl groups, substituted or unsubstituted heterocyclic groups, or substituted or unsubstituted aryl groups; and Ar and Ar′ are groups independently chosen from substituted or unsubtituted aryl groups having from 6 to about 50 carbon atoms.
Another aspect of the present application is directed to a process for forming a compound. The process comprises reacting (i) a hydrocarbyl phenol, (ii) a hindered phenol, (iii) a diaryldiamine and (iv) an aldehyde.
Another aspect of the present application is directed to a lubricant composition. The lubricant composition comprises a base oil and a first compound that is the reaction product of (i) a hydrocarbyl phenol, (ii) a hindered phenol, (iii) a diaryldiamine and (iv) an aldehyde.
Another aspect of the present application is directed to an additive package composition. The additive package composition comprises a diluent and a first compound that is the reaction product of (i) a hydrocarbyl phenol, (ii) a hindered phenol, (iii) a diaryldiamine and (iv) an aldehyde.
Another aspect of the present application is directed to a method for reducing the oxidation of a lubricating oil. The method comprises placing in the crankcase of an internal combustion engine a lubricating composition of the present application having a first compound, where the amount of oxidation of the oil is reduced compared to the amount of oxidation that would have occurred if the lubricating composition did not comprise the first compound.
Additional aspects and advantages of the disclosure will be set forth in part in the description which follows, and can be learned by practice of the disclosure. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure, as claimed.

DESCRIPTION OF THE EMBODIMENTS

The present application is directed to novel compounds and methods of making the compounds. In some embodiments, the compounds can be the reaction product of (i) a hydrocarbyl phenol, (ii) a hindered phenol, (iii) a diaryldiamine and (iv) an aldehyde. In some aspects of the present application, the resulting compounds comprise both a hindered phenol functional group and a diaryldiamine functional group. The plurality of functional groups of the compounds of the present application may result in useful properties, such as, for example, compounds having good antioxidant function and/or other capabilities, as described in more detail below.
Non-limiting examples of suitable hydrocarbyl phenols include compounds of the formula I,
wherein R¹and R²can be chosen from hydrogen or hydrocarbyl groups, with the proviso that at least one of R¹and R²is a hydrocarbyl group. As seen from formula I, R¹and R²can be at ortho, meta or para positions. In one embodiment, R¹is a hydrogen and R²is a linear or branched C₁to C₅₀aliphatic group, such as a C₁to C₅₀alkyl group or polyisobutenyl group, in the para position. Examples of polyisobutenyl groups include polyisobutenyl with a molecular weight ranging from about 100 to about 6000 daltons and a vinylidene content ranging from about 4% to greater than about 90%. Nonlimiting examples of suitable hydrocarbyl phenols include 4-dodecylphenol and (polyisobutenyl)phenol.
As used herein, the term “hydrocarbyl group” or “hydrocarbyl” is used in its ordinary sense, which is well-known to those skilled in the art. Specifically, it refers to a group having a carbon atom directly attached to the remainder of a molecule and having a predominantly hydrocarbon character. Examples of hydrocarbyl groups include:
(1) hydrocarbon substituents, that is, aliphatic (e.g., alkyl or alkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents, and aromatic-, aliphatic-, and alicyclic-substituted aromatic substituents, as well as cyclic substituents wherein the ring is completed through another portion of the molecule (e.g., two substituents together form an alicyclic radical);
(2) substituted hydrocarbon substituents, that is, substituents containing non-hydrocarbon groups which, in the context of the description herein, do not alter the predominantly hydrocarbon substituent (e.g., halo (especially chloro and fluoro), hydroxy, alkoxy, mercapto, alkylmercapto, nitro, nitroso, and sulfoxy);
(3) hetero-substituents, that is, substituents which, while having a predominantly hydrocarbon character, in the context of this description, contain other than carbon in a ring or chain otherwise composed of carbon atoms. Hetero-atoms include sulfur, oxygen, nitrogen, and encompass substituents such as pyridyl, furyl, thienyl, and imidazolyl. In general, no more than two, or as a further example, no more than one, non-hydrocarbon substituent will be present for every ten carbon atoms in the hydrocarbyl group; in some embodiments, there will be no non-hydrocarbon substituent in the hydrocarbyl group.
Suitable hindered phenols for use in the present application include compounds of formula II,
wherein R³and R⁴can be independently chosen from, for example, hydrogen and a linear or branched C₁to C₁₂alkyl group, with the proviso that at least one of R³and R⁴is a branched C₃to C₁₂alkyl group. Non-limiting examples of phenols suitable for use herein include 2-tert-butylphenol; 2,6-ditert-butylphenol; 2-isopropylphenol; 2,6-diisopropylphenol; 2-sec-butylphenol; 2,6 di-sec-butylphenol; 2-tert-hexylphenol; 2,6-ditert-hexylphenol; 2-tert-butyl-o-cresol; 2-tert-dodecylphenol; 2-tert-decyl-o-cresol and 2-tert-butyl-6-isopropylphenol. In one embodiment, the hindered phenol is 2,6 di-tert-butylphenol.
Suitable diaryldiamines for use in forming the compounds of the present application include reactant compounds of the formula III,
wherein Ar and Ar′ each independently represent a substituted or unsubtituted aryl group having from about 6 to about 50 carbon atoms; and wherein R⁵is an amine substituent. Non-limiting examples of suitable amines include primary amine substituents such as —NH₂, —[NH(CH₂)_n]_mNH₂, —(CH₂)_nNH₂, and —CH₂-aryl-NH₂in which n is an integer ranging from about 1 to about 20, such as from about 1 to about 10, or in another embodiment, from about 2 to about 4; and m is an integer having a value of from about 1 to about 20, such as from about 2 to about 10. Non-limiting examples of other substituents that can also be bonded to Ar and Ar′ in addition to the R⁶substituent include one or more additional primary amine substituents, such as those listed above for R⁵; aliphatic hydrocarbon groups, such as alkyl groups having from about 1 to about 20 carbon atoms; hydroxyl; carboxyl and nitro groups.
In some embodiments, both Ar and Ar′ can be phenyl groups. For example, the diaryldiamine can be an N-phenylphenylenediamine (NPPDA), such as N-phenyl-1,3-phenylenediamine, N-phenyl-1,2-phenylenediamine and N-phenyl-1,4-phenylenediamine.
Non-limiting examples of suitable aldehydes include aliphatic aldehydes; such as formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, caproaldehyde, heptaldehyde, and stearaldehyde. Aromatic aldehydes which can be used include benzaldehyde and salicylaldehyde. Non-limiting examples of heterocyclic aldehydes for use herein are furfural and thiophene aldehyde, etc. Also useful are formaldehyde-producing reagents such as paraformaldehyde. In one embodiment, the chosen aldehyde is formaldehyde.
The above described reactant compounds can be employed to produce the product compounds of the present application. The product compounds of the present application include compounds of the following formula V:
wherein Ar, Ar′, R¹, R², R³, R⁴, R⁶and R⁷are defined as set forth above, and where ′R⁵is a secondary amine formed by bonding the R⁵amine of a compound of formula III during the reaction process to form the compound of formula V. Suitable non-limiting examples of ′R⁵secondary amine substituents include —NH—, —[NH(CH₂)_n]_mNH—, —(CH₂)_nNH—, and —CH₂-aryl-NH— in which n and m are as defined above.
In one embodiment, the compounds of the present application include compounds of the following formula VI:
wherein R¹in formula VI is a hydrocarbyl group defined as above.
The process of reacting the reactant compounds described above can be performed in any suitable manner which will produce the desired product compounds of the present application. During the reaction, the aldehyde couples the hindered phenol and diaryldiamine to the hydrocarbyl phenol.
Any suitable amount of the reactants can be employed under any suitable reaction conditions to form the desired product compounds. For example, the reactants can be combined in ratios of from about a 1:x:y:z molar ratio of hydrocarbyl phenol, hindered phenol, diaryldiamine and aldehyde, respectively; where x and y can range from about 1 to about 3; and z can range from 2 to about 4. Suitable reaction temperatures and concentrations of reactants employed informing the compounds of the present application can be determined by one of ordinary skill in the art.
The compounds of the present application may have many uses. For example, the compounds may be useful as antioxidants, anti-knocking agents, and/or as performance enhanced additives useful for improving or maintaining viscosity, or reducing discoloration and/or sludge or deposit formation in a variety of formulations, such as lubricant compositions, fuel compositions, or plastics. Other related applications may also be readily apparent to one of ordinary skill in the art.
The lubricating compositions disclosed herein can comprise a base oil. Base oils suitable for use in formulating the disclosed compositions can be selected from, for example, synthetic or mineral oils, or mixtures thereof.
The base oil can be present in a major amount, wherein “major amount” is understood to mean greater than or equal to 50% by weight of the lubricant composition, such as from about 80% to about 98% by weight of the lubricant composition. The base oil typically has a viscosity of, for example, from about 2 to about 15 cSt and, as a further example, from about 2 to about 10 cSt at 100° C.
Non-limiting examples of mineral oils suitable as base oils include animal oils and vegetable oils (e.g., castor oil, lard oil) as well as other mineral lubricating oils such as liquid petroleum oils and solvent treated or acid-treated mineral lubricating oils of the paraffinic, naphthenic or mixed paraffinic-naphthenic types. Oils derived from coal or shale are also suitable. Further, oils derived from a gas-to-liquid process are also suitable.
Non-limiting examples of synthetic oils include hydrocarbon oils such as polymerized and interpolymerized olefins (e.g., polybutylenes, polypropylenes, propylene isobutylene copolymers, etc.); polyalphaolefins such as poly(1-hexenes), poly-(1-octenes), poly(1-decenes), etc. and mixtures thereof; alkylbenzenes (e.g., dodecylbenzenes, tetradecylbenzenes, di-nonylbenzenes, di-(2-ethylhexyl)benzenes, etc.); polyphenyls (e.g., biphenyls, terphenyl, alkylated polyphenyls, etc.); alkylated diphenyl ethers and alkylated diphenyl sulfides and the derivatives, analogs and homologs thereof and the like.
Alkylene oxide polymers and interpolymers and derivatives thereof where the terminal hydroxyl groups have been modified by esterification, etherification, etc., constitute another class of known synthetic oils that can be used. Such oils are exemplified by the oils prepared through polymerization of ethylene oxide or propylene oxide, the alkyl and aryl ethers of these polyoxyalkylene polymers (e.g., methyl-polyisopropylene glycol ether having an average molecular weight of about 1000, diphenyl ether of polyethylene glycol having a molecular weight of about 500-1000, diethyl ether of polypropylene glycol having a molecular weight of about 1000-1500, etc.) or mono- and polycarboxylic esters thereof, for example, the acetic acid esters, mixed C_3-8fatty acid esters, or the C₁₃Oxo acid diester of tetraethylene glycol.
Another class of synthetic oils that can be used includes the esters of dicarboxylic acids (e.g., phthalic acid, succinic acid, alkyl succinic acids, alkenyl succinic acid, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkyl malonic acids, alkenyl malonic acids, etc.) with a variety of alcohols (e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether, propylene glycol, etc.) 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, the 2-ethylhexyl diester of linoleic acid dimer, the complex ester formed by reacting one mole of sebacic acid with two moles of tetraethylene glycol and two moles of 2-ethylhexanoic acid and the like.
Esters useful as synthetic oils also include those made from C_6-12monocarboxylic acids and polyols and polyol ethers such as neopentyl glycol, trimethylol propane, pentaerythritol, dipentaerythritol, tripentaerythritol, etc.
Hence, the base oil used to make the compositions as described herein can be selected from any of the base oils in Groups I-V as specified in the American Petroleum Institute (API) Base Oil Interchangeability Guidelines. Such base oil groups are as follows:
Group I contain less than 90% saturates and/or greater than 0.03% sulfur and have a viscosity index greater than or equal to 80 and less than 120; Group II contain greater than or equal to 90% saturates and less than or equal to 0.03% sulfur and have a viscosity index greater than or equal to 80 and less than 120; Group III contain greater than or equal to 90% saturates and less than or equal to 0.03% sulfur and have a viscosity index greater than or equal to 120; Group IV are polyalphaolefins (PAO); and Group V include all other basestocks not included in Group I, II, III or IV.
The test methods used in defining the above groups are ASTM D2007 for saturates; ASTM D2270 for viscosity index; and one of ASTM D2622, 4294, 4927 and 3120 for sulfur.
Group IV basestocks, i.e. polyalphaolefins (PAO) include hydrogenated oligomers of an alpha-olefin, the most important methods of oligomerisation being free radical processes, Ziegler catalysis, and cationic, Friedel-Crafts catalysis.
The polyalphaolefins typically have viscosities in the range of 2 to 100 cSt at 100° C., for example 4 to 8 cSt at 100° C. They can, for example, be oligomers of branched or straight chain alpha-olefins having from about 2 to about 30 carbon atoms; non-limiting examples include polypropenes, polyisobutenes, poly-1-butenes, poly-1-hexenes, poly-1-octenes and poly-1-decene. Included are homopolymers, interpolymers and mixtures.
Regarding the balance of the basestock referred to above, a “Group I basestock” also includes a Group I basestock with which basestock(s) from one or more other groups can be admixed, provided that the resulting admixture has characteristics falling within those specified above for Group I basestocks.
Exemplary basestocks include Group I basestocks and mixtures of Group II basestocks with Group I basestock.
Basestocks suitable for use herein can be made using a variety of different processes including but not limited to distillation, solvent refining, hydrogen processing, oligomerisation, esterification, and re-refining.
The base oil can be an oil derived from Fisher-Tropsch synthesized hydrocarbons. Fisher-Tropsch synthesized hydrocarbons can be made from synthesis gas containing H₂and CO using a Fischer-Tropsch catalyst. Such hydrocarbons typically require further processing in order to be useful as the base oil. For example, the hydrocarbons can be hydroisomerized using processes disclosed in U.S. Pat. Nos. 6,103,099 or 6,180,575; hydrocracked and hydroisomerized using processes disclosed in U.S. Pat. Nos. 4,943,672 or 6,096,940; dewaxed using processes disclosed in U.S. Pat. No. 5,882,505; or hydroisomerized and dewaxed using processes disclosed in U.S. Pat. Nos. 6,013,171; 6,080,301; or 6,165,949.
Unrefined, refined and rerefined oils, either mineral or synthetic (as well as mixtures of two or more of any of these) of the type disclosed hereinabove can be used in the base oils. Unrefined oils are those obtained directly from a mineral or synthetic source without further purification treatment. For example, a shale oil obtained directly from retorting operations, a petroleum oil obtained directly from primary distillation or ester oil obtained directly from an esterification process and used without further treatment would be an unrefined oil. Refined oils are similar to the unrefined oils except they have been further treated in one or more purification steps to improve one or more properties. Many such purification techniques are known to those skilled in the art such as solvent extraction, secondary distillation, acid or base extraction, filtration, percolation, etc. Rerefined oils are obtained by processes similar to those used to obtain refined oils, where the processes are applied to refined oils which have been already used in service. Such rerefined oils are also known as reclaimed or reprocessed oils and often are additionally processed by techniques directed to removal of spent additives, contaminants, and oil breakdown products.
The lubricant compositions of the present application can be used in any engine or other combustion systems or mechanical devices that may benefit therefrom. For example, the lubricant compositions can be suitable for use in the crank case of an internal combustion engine.
The product compounds of the present application can be added in an amount sufficient to provide the desired result. For example, where the product compound is added as antioxidant to a lubricant, an amount ranging from about 0.05 to about 10 weight percent, such as from about 0.1 to about 4 weight percent, relative to the total amount of the lubricant composition is usually sufficient.
By employing the product compounds of the present application in lubricants used, for example, in the crankcase of an internal combustion engine, the amount of oxidation of the oil in the lubricant may be reduced compared to the amount of oxidation that would have occurred if the lubricating composition did not comprise the compound of the present application, under the same engine operating conditions.
In some embodiments, the compounds of the present application can be added to the oil in the form of an additive package composition. These are concentrates dissolved in a diluent, such as mineral oil, synthetic hydrocarbon oils, and mixtures thereof. When added to the base oil, the additive package composition can provide an effective concentration of the additives in the base oil. The amount of the compounds of the present application in the additive package can vary from about 5 wt % to about 75 wt % of the additive package, such as from about 10 wt % about 50 wt %.
The additive compositions and finished lubricants of the present application can contain other additional additives. Non-limiting examples of such additional additives include dispersants, detergents, anti-wear agents, supplemental antioxidants, viscosity index improvers, pour point depressants, corrosion inhibitors, rust inhibitors, foam inhibitors, anti-swell agents and friction modifiers. Such additives are well known in the art, and choosing effective amounts of these additional additives in lubricant compositions would be within the ordinary skill of the art.
The following examples are presented to illustrate the manner in which the additives of the invention can be prepared and are not to be considered as limiting as to any aspect thereof.

EXAMPLES

Example 1

A 2-liter 4-neck flask was equipped with a nitrogen atmosphere and reflux condenser. The flask was charged with 950 g of (polyisobutenyl)phenol and a few drops of a defoamer. With agitation, the contents in the flask were heated to 80° C. and 138 g of N-phenyl-phenylenediamine (NPPDA) was added in portions, followed by dropwise addition of 60.8 g of 37% aqueous solution of formaldehyde over approximately 90 min. The reaction was then held at 80° C. for 4 hrs and then at reflux for 4 hrs. The reaction mixture was vacuum stripped at 110° C. The product was diluted with 336 g of process oil and then filtered over Celite. A total of approx. 1307 g of product thus obtained had TAN (total acid number) of 28.6 and % N=1.52.
552.6 g of the above product and 61.8 g of 2,6-ditertbutylphenol were charged to a 1-liter flask equipped with nitrogen atmosphere and reflux condenser. With agitation, the contents in the flask were heated to 60° C. and 1.5 g of dimethylaminopropylamine (DMAPA) catalyst was added followed by dropwise addition of 24.3 g of 37% aqueous solution of formaldehyde over approximately 20 min. The reaction was then held at 60° C. for 3.5 hrs. Reflux condenser was replaced with a distillation condenser and the temperature then gradually raised to 150° C. The reaction mixture was diluted with 45 g of process oil and then filtered over Celite. A total of approximately 548 g of product thus obtained had TAN (total acid number) of 15.6 and % N=1.31.

Example 2

A 1-liter 4-neck flask was charged with 314.4 g of 4-dodecylphenol and 247.2 g of 2,6-ditertbutylphenol and equipped with nitrogen atmosphere and reflux condenser. With agitation, the contents in the flask were heated to 60° C. and 6 g of DMAPA catalyst was added followed by dropwise addition of 97.2 g of 37% aqueous solution of formaldehyde over approximately 20 min. The reaction was then held at 60° C. for 1 hr. Reflux condenser was replaced with a distillation condenser and the temperature then gradually raised to 150° C. A total of approximately 558 g of product thus obtained had TAN (total acid number) of 122.4.
344 g of the above product, 321.7 g of process oil and few drops of a defoamer were charged to a 1-liter flask equipped with nitrogen atmosphere and reflux condenser. With agitation, the contents in the flask were heated to 80° C. and 128.8 g of N-phenyl-phenylenediamine (NPPDA) was added in portions, followed by dropwise addition of 60.8 g of 37% aqueous solution of formaldehyde over approximately 2 hrs. The reaction was then held at 80° C. for 4 hrs and then at reflux for 4 hrs. The reaction mixture was vacuum stripped at 110° C. The product was then filtered over Celite. A total of approx 691.5 g of product thus obtained had TAN (total acid number) of 51 and % N=2.39.
For the purposes of this specification and appended claims, unless otherwise indicated, all numbers expressing quantities, percentages or proportions, and other numerical values used in the specification and claims, are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by the present disclosure. A the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.
It is noted that, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the,” include plural referents unless expressly and unequivocally limited to one referent. Thus, for example, reference to “an acid” includes two or more different acids. As used herein, the term “include” and its grammatical variants are intended to be non-limiting, such that recitation of items in a list is not to the exclusion of other like items that can be substituted or added to the listed items.
While particular embodiments have been described, alternatives, modifications, variation, improvements, and substantial equivalents that are or can be presently unforeseen can arise to applicants or others skilled in the art. Accordingly, the appended claims as filed and as they can be amended are intended to embrace all such alternatives, modifications variation, improvement, and substantial equivalents.

Claims

1. A compound that is the reaction product of (i) a hydrocarbyl phenol, (ii) a hindered phenol, (iii) an diaryldiamine and (iv) an aldehyde.

2. The compound of claim 1, wherein the hydrocarbyl phenol is a compound of the formula I,

wherein R¹and R²are independently chosen from hydrogen or hydrocarbyl groups, with the proviso that at least one of R¹and R²is a hydrocarbyl group.

3. The compound of claim 1, wherein the hindered phenol is a compound of the formula II,

wherein R³and R⁴are independently chosen from hydrogen and a linear or branched C₁to C₁₂alkyl group, with the proviso that at least one of R³and R⁴is a branched C₃to C₁₂alkyl group.

4. The compound of claim 1, wherein the hindered phenol is a compound chosen from 2-tert-butylphenol; 2,6-ditert-butylphenol; 2-isopropylphenol; 2,6diisopropylphenol; 2-sec-butylphenol; 2,6 di-sec-butylphenol; 2-tert-hexylphenol; 2,6-ditert-hexylphenol; 2-tert-butyl-o-cresol; 2-tert-dodecylphenol; 2-tert-decyl-o-cresol and 2-tert-butyl-6-isopropylphenol.

5. The compound of claim 1, wherein the hindered phenol is 2,6 di-tert butyl phenol.

6. The compound of claim 1, wherein the diaryldiamine is a compound of the formula III,

where Ar and Ar′ each independently represent a substituted or unsubtituted aryl group having from 6 to 50 carbon atoms; and

R⁶is an amine substituent.

7. The compound of claim 6, wherein R⁵is a substituent chosen from —NH₂, —[NH(CH₂)_n]_mNH₂, —(CH₂)_nNH₂, and —CH₂-aryl-NH₂, in which n and m are each an integer having a value of from about 1 to about 20.

8. The compound of claim 7, wherein at least one of Ar and Ar′ is substituted with one or more substituents in addition to R⁵, the one or more additional substituents being chosen from primary amine substituents, aliphatic hydrocarbon groups, hydroxyl groups, carboxyl groups, and nitro groups.

9. The compound of claim 6, wherein Ar and Ar′ are phenyl groups.

10. The compound of claim 1, wherein the diaryldiamine is a compound chosen from N-phenyl-1,3-phenylenediamine, N-phenyl-1,2-phenylenediamine and N-phenyl-1,4-phenylenediamine.

11. The compound of claim 1, wherein the aldehyde is chosen from formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, caproaldehyde, heptaldehyde, stearaldehyde, benzaldehyde, salicylaldehyde, furfural, thiophene aldehyde, and paraformaldehyde.

12. A compound of formula V,

wherein R¹and R²are independently chosen from hydrogen and hydrocarbyl groups, with the proviso that at least one of R¹and R²is a hydrocarbyl group;

R³and R⁴are independently chosen from hydrogen and a linear or branched C₁to C₁₂alkyl group, with the proviso that at least one of R³and R⁴is a branched to C₃to C₁₂alkyl group;

′R⁵is a secondary amine substituent;

R⁵and R⁷are independently chosen from hydrogen, C₁to C₁₈linear, branched or cyclic alkyl groups, substituted or unsubstituted heterocyclic groups, or substituted or unsubstituted aryl groups, and

Ar and Ar′ are groups independently chosen from substituted or unsubtituted aryl groups having from 6 about 50 carbon atoms.

13. A process for forming a compound, the process comprising reacting (i) a hydrocarbyl phenol, (ii) a hindered phenol, (iii) a diaryldiamine and (iv) an aldehyde.

14. The process of claim 13, wherein the hydrocarbyl phenol is a compound of the formula I,

wherein R¹and R²are chosen from hydrogen or hydrocarbyl groups, with the proviso that at least one of R¹and R²is hydrocarbyl group.

15. The process of claim 13, wherein the hindered phenol is a compound of the formula II,

where R³and R⁴are independently chosen from hydrogen or a linear or branched C₁to C₁₂alkyl group, with the proviso that at least one of R³and R⁴is a branched C₃to C₁₂alkyl group.

16. The process of claim 13, wherein the diaryldiamine is a compound of the formula III,

R⁵is an amine substituent.

17. The process of claim 13, wherein the aldehyde is chosen from formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, caproaldehyde, heptaldehyde, stearaldehyde, benzaldehyde, salicylaldehyde, furfural, thiophene aldehyde, and paraformaldehyde.

18. A lubricant composition comprising:

a base oil; and

a first compound that is the reaction product of (i) a hydrocarbyl phenol, (ii) a hindered phenol, (iii) a diaryldiamine and (iv) an aldehyde.

19. The lubricant composition of claim 18, wherein the concentration of the first compound ranges from about 0.05 wt % to about 10 wt % of the lubricant composition.

20. The lubricant composition of claim 18, further comprising one or more additional additives chosen from dispersants, detergents, anti-wear agents, supplemental antioxidants, viscosity index improvers, pour point depressants, corrosion inhibitors, rust inhibitors, foam inhibitors, anti-swell agents and friction modifiers.

21. The lubricant composition of claim 18, wherein:

the hydrocarbyl phenol is a compound of the formula I,

wherein R¹and R²are chosen from hydrogen or hydrocarbyl groups, with the proviso that at least one of R¹and R²is a hydrocarbyl group;

the hindered phenol is a compound of the formula II,

where R³and R⁴are independently chosen from hydrogen and a linear or branched C₁to C₁₂alkyl group, with the proviso that at least one of R³and R⁴is a branched C₃to C₁₂alkyl group;

the diaryldiamine is a compound of the formula III,

where Ar and Ar′ each independently represent a substituted or unsubtituted aryl group having from 6 to 50 carbon atoms and R⁵is an amine substituent; and

the aldehyde is chosen from formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, caproaldehyde, heptaldehyde, stearaldehyde, benzaldehyde, salicylaldehyde, furfural, thiophene aldehyde, and paraformaldehyde.

22. The lubricant composition of claim 21, wherein R⁵is a substituent chosen from —NH₂, —[NH(CH₂)_n]_mNH₂, —(CH₂)_nNH₂, and —CH₂-aryl-NH₂, in which n and m are each an integer having a value of from about 1 to about 20; and wherein Ar and Ar′ are phenyl groups.

23. The lubricant composition of claim 21, wherein the hindered phenol is a compound chosen from 2-tert-butylphenol; 2,6-ditert-butylphenol; 2-isopropylphenol; 2,6-diisopropylphenol; 2-sec-butylphenol; 2,6 di-sec-butylphenol; 2-tert-hexylphenol; 2,6-ditert-hexylphenol; 2-tert-butyl-o-cresol; 2-tert-dodecylphenol; 2-tert-decyl-o-cresol and 2-tert-butyl-6-isopropylphenol.

24. The lubricant composition of claim 21, wherein the diaryldiamine is a compound chosen from N-phenyl-1,3-phenylenediamine, N-phenyl-1,2-phenylenediamine and N-phenyl-1,4-phenylenediamine.

25. A additive package composition comprising:

a diluent; and

26. The additive package composition of claim 25, wherein the concentration of the first compound ranges from about 5 wt % to about 75 wt % of the additive package composition.

27. The additive package composition of claim 25, further comprising one or more additional additives chosen from dispersants, detergents, anti-wear agents, supplemental antioxidants, viscosity index improvers, pour point depressants, corrosion inhibitors, rust inhibitors, foam inhibitors, anti-swell agents and friction modifiers.

28. The additive package of claim 25, wherein:

the hydrocarbyl phenol is a compound of the formula I,

the hindered phenol is a compound of the formula II,

the diaryldiamine is a compound of the formula III,

29. The additive package of claim 28, wherein R⁵is a substituent chosen from —NH₂, —[NH(CH₂)_n]_mNH₂, —(CH₂)_nNH₂, and —CH₂-aryl-NH₂, in which n and m are each an integer having a value of from about 1 to about 20; and wherein Ar and Ar′ are phenyl groups.

30. The additive package of claim 28, wherein the hindered phenol is a compound chosen from 2-tert-butylphenol; 2,6-ditert-butylphenol; 2-isopropylphenol; 2,6-diisopropylphenol; 2-sec-butylphenol; 2,6-di-sec-butylphenol; 2-tert-hexylphenol; 2,6-ditert-hexylphenol, 2-tert-butyl-o-cresol; 2-tert-dodecylphenol; 2-tert-decyl-o-cresol and 2-tert-butyl-6-isopropylphenol.

31. The additive package of claim 28, wherein the diaryldiamine is a compound chosen from N-phenyl-1,3-phenylenediamine, N-phenyl-1,2-phenylenediamine and N-phenyl-1,4-phenylenediamine.

32. A method for reducing the oxidation of a lubricating oil, the method comprising placing in the crankcase of an internal combustion engine a lubricating composition according to claim 18, where the amount of oxidation of the oil is reduced compared to the amount of oxidation that would have occurred if the lubricating composition did not comprise the first compound.