CN118006380A - Corrosion inhibitors and industrial lubricants containing the same - Google Patents

Abstract

Disclosed herein are corrosion inhibitors suitable for reloading industrial lubricants and industrial lubricating compositions, including such corrosion inhibitors in combination with phosphonic acid diesters to provide good copper corrosion and roller bearing protection. The corrosion inhibitor has a high content of a dialkyl dithiothiadiazole compound configured to maintain high levels of phosphonate diester in the lubricant.

Description

Corrosion inhibitors and industrial lubricants containing the same

Technical Field

The present disclosure relates to corrosion inhibitors suitable for heavy duty lubricants or industrial lubricants that achieve good wear performance, low copper corrosion, and/or low roller bearing weight loss.

Background

Driveline hardware such as gears, shafts, etc. typically require lubricants that provide antiwear or extreme pressure protection. In practice, gears and shafts may work at full capacity and/or frequently stop-and-go operation, imposing additional stress and strain on the hardware. Thus, lubricants for heavy duty gear and shaft applications require chemical additives to reliably protect the gears and shafts under full load and stop-and-go operating conditions.

Typically, lubricants used in such heavy duty applications require that the fluid meet one or more performance characteristics, such as extreme pressure, antiwear, friction, and/or copper corrosion, to suggest some common requirements for driveline hardware fluids. Various additives may be included in the lubricant to achieve such properties. For example, lubricants often contain a vulcanization additive, such as a thiadiazole compound, to protect gears and other components from corrosion and wear. Typically, these lubricants will also have a phosphorus compound to act as an antiwear additive or friction modifier. One means of determining the antiwear capability of gear lubricants is to run the FE8 bearing test (80 hours, 7.5rpm,100kN and 80 ℃) in accordance with DIN 51819-3. Phosphonic acid diesters, and in particular octadecyl dimethyl phosphonate, are known to provide bearing protection in FE8 bearing tests. Unfortunately, thiadiazole corrosion inhibitors, when used in combination with a phosphonate diester, tend to interact with the diester and can degrade the diester to the monoester form. However, monoester variants of phosphonates are less effective in preventing roller bearing wear. Thus, there is a need to modify thiadiazole corrosion inhibitors in a manner that both maintains their effectiveness as corrosion inhibitors, and also allows the phosphonic acid diesters to function as antiwear additives or friction modifiers.

Disclosure of Invention

In one method or embodiment, described herein is a corrosion inhibitor prepared by a method comprising the steps of: (a) Reacting 1,3, 4-dimercaptothiadiazole or an alkali metal salt thereof with an alkyl mercaptan in the presence of an acid to form a first reaction intermediate; (b) Reacting the first reaction intermediate with hydrogen peroxide to form a corrosion inhibitor; and (c) wherein the 1,3, 4-dimercaptothiadiazole or alkali metal salt thereof, the alkyl mercaptan, and hydrogen peroxide are provided in a molar ratio of 1:1.95 to 2.15:greater than 2.0.

In other methods or embodiments, the corrosion inhibitor of the preceding paragraph may be combined with the optional features or embodiments in any combination. These optional features or embodiments may include one or more of the following: wherein the acid is a strong acid provided in molar excess relative to the 1,3, 4-dimercaptothiadiazole; and/or wherein the corrosion inhibitor is about 95% by weight or more of a2, 5-dialkyl-dithiothiadiazole compound and about 5% by weight or less of a monoalkyl-dithiothiadiazole compound; and/or wherein the corrosion inhibitor has a total acid number of 10 or less; and/or wherein the method further comprises heating the corrosion inhibitor to a temperature effective to separate any aqueous layer, and optionally subjecting the heated corrosion inhibitor to vacuum stripping; and/or wherein the 2, 5-dialkyl-dithiothiadiazole compound has the structure of formula Ia:

And wherein the monoalkyl-dithiothiadiazole compound has the structure of formula Ib:

Wherein each R ₁ of formula Ia and/or formula Ib is independently a linear or branched C4 to C20 hydrocarbyl group; and/or wherein the alkyl portion of the alkyl thiol is an aliphatic or aromatic hydrocarbyl group; and/or wherein the alkyl portion of the alkyl mercaptan is a linear or branched C1 to C30 hydrocarbyl group; and/or wherein the dimercaptothiadiazole or alkali metal salt thereof, the alkyl mercaptan, and hydrogen peroxide are provided in a molar ratio of 1:1.95 to 2.15:2.1 to 2.4.

In another method or embodiment, described herein is a lubricant comprising: (a) a major amount of a base oil; and (b) a corrosion inhibitor prepared by a process comprising the steps of: (i) Reacting 1,3, 4-dimercaptothiadiazole or an alkali metal salt thereof with an alkyl mercaptan in the presence of an acid to form a first reaction intermediate; (ii) Reacting the first reaction intermediate with hydrogen peroxide to form a corrosion inhibitor; and (iii) wherein the 1,3, 4-dimercaptothiadiazole or alkali metal salt thereof, the alkyl mercaptan, and hydrogen peroxide are provided in a molar ratio of 1:1.95 to 2.15:greater than 2.0.

In other methods or embodiments, the lubricant of the preceding paragraph may be combined with the optional features or embodiments in any combination. These optional features or embodiments may include one or more of the following: wherein the acid is a strong acid provided in molar excess relative to the 1,3, 4-dimercaptothiadiazole; and/or the lubricant further comprises one or more phosphonate compounds comprising about 90 wt.% or more phosphonate diester and no more than about 10 wt.% phosphonate monoester, based on the total weight percent of phosphonate compounds; and/or wherein the corrosion inhibitor is about 95% by weight or more of a2, 5-dialkyl-dithiothiadiazole compound and about 5% by weight or less of a monoalkyl-dithiothiadiazole compound; and/or wherein the 2, 5-dialkyl-dithiothiadiazole compound has the structure of formula Ia:

And wherein the monoalkyl-dithiothiadiazole compound has the structure of formula Ib:

Wherein each R ₁ of formula Ia and/or formula Ib is independently a linear or branched C4 to C20 hydrocarbyl group; and/or wherein the phosphonate diester has the structure of formula II

Wherein R ₂ is a C1 to C50 hydrocarbyl group and each R ₃ is independently a C1 to C20 alkyl group; and/or wherein the phosphonate diester is dimethyl octadecylphosphonate (DMOP); and/or wherein the phosphonate monoester has the structure of formula III

Wherein R ₄ is a C1 to C50 hydrocarbyl group and R ₅ is a C1 to C20 alkyl group; and/or wherein the phosphonate monoester is octadecyl methyl phosphonate (MOP); and/or wherein the method further comprises heating the corrosion inhibitor to a temperature effective to separate any aqueous layer, and optionally subjecting the heated corrosion inhibitor to vacuum stripping; and/or wherein the lubricant exhibits a FAG FE8 roller bearing weight loss of about 12mg or less in accordance with DIN 51819-3 after 80 hours of operation at 80 ℃, 7.5rpm and 100 kN.

In further methods or embodiments, described herein is a corrosion inhibitor additive comprising: (a) About 95% by weight or more of a2, 5-dialkyl-dithiothiadiazole compound; (b) A monoalkyl-dithiothiadiazole compound, but no more than about 5% by weight of a monoalkyl-dithiothiadiazole compound; and (c) wherein the corrosion inhibitor additive has a total acid number of about 10 or less.

In other methods or embodiments, the corrosion inhibitor additive of the preceding paragraph may be combined with the optional features or embodiments in any combination. These optional features or embodiments may include one or more of the following: wherein the 2, 5-dialkyl-dithiothiadiazole compound has the structure of formula Ia:

And wherein the monoalkyl-dithiothiadiazole compound has the structure of formula Ib:

Wherein each R ₁ of formula Ia and/or formula Ib is independently a linear or branched C4 to C20 hydrocarbyl group; and/or wherein the corrosion inhibitor is obtained from dimercaptothiadiazole or an alkali metal salt thereof, an alkyl mercaptan, and hydrogen peroxide provided in a molar ratio of 1:1.95-2.15:2.1-2.4.

In further methods or embodiments, the use of any of the embodiments of the corrosion inhibitors or lubricants of the present disclosure is described for achieving a weight loss through a FAG FE8 roller bearing of about 12mg or less in accordance with DIN 51819-3 after 80 hours of operation at 80 ℃, 7.5rpm and 100 kN.

Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. The following term definitions are provided to clarify the meaning of certain terms as used herein.

The terms "gear oil", "gear fluid", "gear lubricant", "base gear lubricant", "lubricating oil", "lubricant composition", "lubricating composition", "lubricant" and "lubricating fluid" refer to the finished lubricating product comprising a major amount of a base oil as discussed herein and a minor amount of an additive composition as discussed herein. Such gear fluids are used under extreme pressure conditions, for example, in transmissions and gear drive components having metal-to-metal contact conditions, such as in transmissions (manual or automatic) and/or gear type differentials.

As used herein, the term "hydrocarbyl substituent" or "hydrocarbyl group" is used in its ordinary sense, as is well known to those skilled in the art. In particular, it refers to a group having a carbon atom directly attached to the rest of the molecule and having predominantly hydrocarbon character. Each hydrocarbyl group is independently selected from the group consisting of hydrocarbon substituents and substituted hydrocarbon substituents containing one or more halogen groups, hydroxyl groups, alkoxy groups, mercapto groups, nitro groups, nitroso groups, amino groups, pyridyl groups, furyl groups, imidazolyl groups, oxygen, and nitrogen, and wherein no more than two non-hydrocarbon substituents are present for every ten carbon atoms in the hydrocarbyl group.

As used herein, unless explicitly stated otherwise, the term "percent by weight" or "wt%" or "weight percent" means the percentage of the component by weight of the entire composition. All percentages herein are by weight unless otherwise indicated.

The terms "soluble", "oil-soluble" or "dispersible" as used herein may, but do not necessarily, indicate that the compound or additive is soluble, miscible or capable of being suspended in oil in all proportions. However, the foregoing terms do mean that they are, for example, soluble, suspendable, soluble or stably dispersible in oil to an extent sufficient to exert their intended effect in the environment in which the oil is employed. Furthermore, the additional incorporation of other additives may also allow for the incorporation of higher levels of specific additives, if desired.

As used herein, the term "alkyl" refers to straight, branched, cyclic, and/or substituted saturated chain moieties of from about 1 to about 200 carbon atoms. As used herein, the term "alkenyl" refers to straight, branched, cyclic, and/or substituted unsaturated chain moieties of from about 3 to about 30 carbon atoms. As used herein, the term "aryl" refers to mono-and polycyclic aromatic compounds that may include alkyl, alkenyl, alkylaryl, amino, hydroxyl, alkoxy, halogen substituents, and/or heteroatoms including, but not limited to, nitrogen and oxygen.

As used herein, molecular weight is determined by Gel Permeation Chromatography (GPC) using commercially available polystyrene standards (having Mn of about 180 to about 18,000 as a calibration reference). The molecular weight (Mn) of any of the embodiments herein can be measured using Gel Permeation Chromatography (GPC) instruments and the like available from Waters, and the data processed using software such as Waters Empower software. The GPC instrument can be equipped with a Waters separation module and a Waters refractive index detector (or similar optional device). GPC operating conditions may include guard columns, 4 Agilent PLgel columns (300X 7.5mm in length; 5 μ in particle size, and pore size rangeThe column temperature was about 40 ℃. Unstabilized HPLC grade Tetrahydrofuran (THF) can be used as the solvent at a flow rate of 1.0mL/min. GPC instruments may be calibrated with commercially available Polystyrene (PS) standards having narrow molecular weight distributions ranging from 500g/mol to 380,000 g/mol. For samples with a mass of less than 500g/mol, the calibration curve can be extrapolated. The samples and PS standards were soluble in THF and prepared at concentrations of 0.1 wt% to 0.5 wt% and used without filtration. GPC measurements are also described in U.S. Pat. No. 5,266,223, incorporated herein by reference. The GPC method additionally provides molecular weight distribution information; see, e.g., w.w.yau, j.j.kirkland d.d.bly, "modern size exclusion chromatography (Modern Size Exclusion Liquid Chromatography)", john Wiley and Sons, new York,1979, also incorporated herein by reference.

It should be understood that throughout this disclosure, the terms "comprises," "comprising," "includes," "including," and the like are to be construed as open-ended, and include any element, step, or ingredient not explicitly listed. The phrase "consisting essentially of … …" is intended to include any explicitly listed elements, steps, or ingredients as well as any additional elements, steps, or ingredients that do not materially affect the basic and novel aspects of the invention. The present disclosure also contemplates that any composition described using the terms "comprising," "including," "containing," and "containing" are also to be construed as including the disclosure of the same composition "consisting essentially of, or" consisting of, its specifically listed components.

Drawings

FIG. 1 is a graph of the comparison of MOP weight percent in an industrial lubricant of the present invention subjected to aging at about 40 ℃; and

FIG. 2 is a graph of the comparison of aging at about 55℃and the percentage by weight of MOP in the industrial lubricant of the present invention.

Detailed Description

In one method or embodiment, disclosed herein are corrosion inhibitors suitable for heavy duty lubricants and/or industrial lubricants, and industrial lubricating compositions comprising such corrosion inhibitors. In some embodiments, the industrial lubricating compositions herein include a unique corrosion inhibitor in combination with one or more phosphonic acid diesters to provide both good copper corrosion and roller bearing protection. Corrosion inhibitors and lubricants comprising such corrosion inhibitors are suitable for use as industrial gear oils for transmission fluids (i.e., manual, automatic, or dual clutch transmissions), gear fluids, axle fluids, differential fluids, and/or lubrication fluids for other gear type applications (such as turbines, wind turbines, etc.) configured for heavy duty applications.

In one aspect of the present disclosure, a corrosion inhibitor is prepared by a unique process wherein the molar ratio of dimercaptothiadiazole or alkali metal salt thereof, alkyl mercaptan, and hydrogen peroxide is selected to form a corrosion inhibitor that maximizes the dialkyl-dithiothiadiazole content. In other methods or embodiments, the corrosion inhibitor has a maximum amount of dialkyl thiadiazole compound and about 95% by weight or more of 2, 5-dialkyl-dithiothiadiazole compound and about 5% by weight or less of mono-alkyl-dithiothiadiazole compound.

In further methods or embodiments, the corrosion inhibitor comprises a mixture of dialkyl dithiothiadiazole and monoalkyl dithiothiadiazole compounds containing about 95% by weight or more of dialkyl-dithiothiadiazole compounds and about 5% by weight or less of monoalkyl-dithio-thiadiazole compounds. Such corrosion inhibitors are suitable for use in lubricants that include one or more phosphonic acid diesters and are configured to maintain high diester levels. In the method, the lubricant herein having a phosphonate diester and a unique corrosion inhibitor further has a phosphonate diester to phosphonate monoester weight ratio of about 90:10 to 98:2 for at least about 8 weeks at 25 ℃, 40 ℃, or 50 ℃.

Corrosion inhibitors

In a method or embodiment, the corrosion inhibitor is a mixture of thiadiazole compounds or derivatives thereof, and in particular, thiadiazole compounds and/or hydrocarbyl-substituted derivatives thereof prepared by a specific method configured to maximize the content of dialkyl-dithiothiadiazole compounds or derivatives thereof in the mixture and minimize the content of any monoalkyl-dithiothiadiazole and/or other bis-thiadiazole contaminants in the mixture.

More specifically, the methods herein are configured to maximize the level of dialkyl-dithiothiadiazole compounds of formula Ia or derivatives thereof in a corrosion inhibitor mixture and minimize the level of monoalkyl dithiothiadiazole compounds of formula Ib in the mixture. In the method, the dialkyl-dithiothiadiazole compound has the structure of formula 1 a:

And the monoalkyl-dithiothiadiazole compound has the structure of formula Ib:

Wherein each R ₁ of formula Ia and/or formula Ib is independently a linear or branched C4 to C20 hydrocarbyl group, and preferably a linear or branched C10 to C16 hydrocarbyl group.

The methods herein are configured to produce mixtures of such thiadiazole compounds, or derivatives thereof, including blends of compounds having the structures of formula Ia and formula Ib, wherein the compounds of formula Ia are maximized in the blend. In other methods, the corrosion inhibitor is a blend of compound Ia and compound Ib, containing about 95 wt.% or more of the compound of formula Ia (preferably about 95 wt.% to about 99.5 wt.%) and about 5 wt.% or less of the compound of formula Ib (preferably about 0.05 wt.% to about 5 wt.%). In another approach, the corrosion inhibitor is a mixture of 2,5 dimercapto 1,3, 4-thiadiazole compounds, including a blend of 2, 5-bis- (nonyldithio) -1,3, 4-thiadiazole (such as about 95 wt.% or more or about 95 wt.% to about 99.5 wt.%) and 2, 5-mono- (nonyldithio) -1,3, 4-thiadiazole (such as about 5 wt.% or less or about 0.05 wt.% to about 5 wt.%).

The corrosion inhibitors herein are prepared in specific reactions having very tightly controlled molar ratios of (i) 1,3, 4-dimercaptothiadiazole or an alkali metal salt thereof, (ii) an alkyl thiol, and (iii) hydrogen peroxide. In a method or embodiment, the novel corrosion inhibitors herein are prepared by a method comprising the steps of: (a) Reacting 1,3, 4-dimercaptothiadiazole or an alkali metal salt thereof with an alkyl mercaptan in the presence of an acid to form a first reaction intermediate; (b) Reacting the first reaction intermediate with hydrogen peroxide to form a corrosion inhibitor; and (c) wherein the dimercaptothiadiazole or alkali metal salt thereof, the alkyl mercaptan, and hydrogen peroxide are provided in a specific molar ratio comprising 1.95 to 2.15 molar equivalents of alkyl mercaptan relative to the thiadiazole, and greater than 2.0 molar equivalents of hydrogen peroxide relative to the thiadiazole, and preferably 2.1 to 2.4 molar equivalents of hydrogen peroxide relative to the thiadiazole. Such tightly controlled reactant molar ratios are configured to maximize the dialkyl-dithiothiadiazole content of the resulting mixture. In general, the 1,3, 4-dimercaptothiadiazole or its alkali metal salt, alkyl mercaptan, and hydrogen peroxide are provided in a molar ratio of 1:1.95 to 2.15:greater than 2.0, and preferably in a molar ratio of 1:1.95 to 2.15:2.1 to 2.4.

In the process, the process herein first reacts 1,3, 4-dimercaptothiadiazole or an alkali metal salt thereof with an alkyl mercaptan in the presence of an optional solvent and/or acid at a temperature of from about 0 ℃ to about 100 ℃, preferably from about 15 ℃ to about 85 ℃, and more preferably from about 70 ℃ to about 85 ℃ to form a first reaction intermediate. If alkali metal salts of dimercaptothiadiazoles are used (such as the sodium salt of 2, 5-dimercapto-l, 3, 4-thiadiazole, or, for example, sodium 2, 5-dimercapto-1, 3, 4-thiadiazole), sufficient amounts of mineral acids such as, for example, sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid, hydrobromic acid, perchloric acid, hydroiodic acid, p-toluenesulfonic acid and/or methanesulfonic acid, and the like, can be used. Preferably, the acid is a strong acid provided in molar excess relative to the 1,3, 4-dimercaptothiadiazole. As used herein, strong acid refers to an acid that dissociates or ionizes completely in aqueous solution. Preferably, the acid is sulfuric acid. The first reaction intermediate may then be further reacted with hydrogen peroxide to form the corrosion inhibitors herein. The hydrogen peroxide and mineral acid (if used) are slowly added in their respective steps and hydrogen peroxide may preferably be added over a period of about 3 hours or more, preferably about 3 hours to about 6 hours, and more preferably about 3 hours to about 4 hours. After the addition of hydrogen peroxide, it may be advantageous to maintain the resulting reaction mixture at a temperature in the above-mentioned range and/or to raise the temperature above 85 ℃ and preferably about 88 ℃ to about 100 ℃ for a short period of time to complete the reaction product of the first reaction step. The organic layer may then optionally be washed with water and/or the solvent optionally removed to produce a first reaction product mixture from the first reaction step.

Suitable alkyl thiols have the general formula R-SH, where R may be an aliphatic or aromatic hydrocarbyl group, including but not limited to acyclic groups, cycloaliphatic groups, aralkyl groups, aryl and alkylaryl groups, or mixtures of such groups. The hydrocarbyl group may comprise from 1 to 30 carbons, and is preferably a linear or branched alkyl group containing from 4 to 16 carbons. Examples of suitable alkyl mercaptans may be, but are not limited to, ethyl mercaptan, propyl mercaptan, butyl mercaptan, hexyl mercaptan, octyl mercaptan, nonyl mercaptan, dodecyl mercaptan, tridecyl mercaptan, cetyl mercaptan, octadecyl mercaptan, cyclohexyl mercaptan, phenyl mercaptan, tolyl mercaptan, benzyl mercaptan, naphthyl mercaptan, styryl mercaptan, and the like, and mixtures thereof. In one method, the preferred alkyl mercaptan is t-nonylthiol.

The reaction step may be carried out in the presence of an optional solvent, if desired. The solvent may be any suitable solvent that is not chemically reactive with hydrogen peroxide. The solvent may be refluxed during the reaction and, if desired, may help control the reaction temperature. Suitable solvents may be water, methanol, acetone, phenol, isopropanol, ethanol, pentanol, ethylene glycol, glycerol, erythritol, and the like, or mixtures thereof.

Inorganic acids may also be used in the reaction, and suitable inorganic acids are those that readily react with sodium or other alkali metal substituents to form water-soluble salts. Such acids include, but are not limited to, sulfuric acid, phosphoric acid, sulfurous acid, phosphorous acid, hydrochloric acid, hydrofluoric acid, and the like, and combinations thereof. In one method, sulfuric acid is preferred.

In some methods or embodiments, the methods herein further comprise heating the thiadiazole corrosion inhibitor to a temperature effective to separate any aqueous layers and optionally subjecting the heated thiadiazole corrosion inhibitor from step to vacuum stripping. If desired, the heating to a temperature of about 100 ℃ to about 110 ℃ may be maintained under vacuum for a period of time ranging from 1 hour to 2 hours to form the final corrosion inhibitors herein.

In some methods, the corrosion inhibitor additive formed includes (a) about 95% by weight or more of a2, 5-dialkyl-dithiothiadiazole compound; (b) A monoalkyl-dithiothiadiazole compound, but no more than about 5% by weight of a monoalkyl-dithiothiadiazole; and (c) wherein the corrosion inhibitor has a total acid number of about 10 or less. In some embodiments, the corrosion inhibitor is obtained from 1,3, 4-dimercaptothiadiazole or an alkali metal salt thereof, an alkyl thiol, and hydrogen peroxide provided in a molar ratio of 1:1.95 to 2.15:2.1 to 2.4.

Suitable treatments for the corrosion inhibitors in the lubricants of the present disclosure may be from about 0.1 wt.% to about 1.0 wt.%, preferably from about 0.2 wt.% to about 0.6 wt.%, and more preferably from about 0.2 wt.% to about 0.4 wt.%.

Phosphonic acid diesters

The industrial or heavy duty lubricating oil compositions herein may also include small amounts of phosphonate diesters to provide improved roller bearing wear protection and the like. If included, the composition may comprise less than about 0.5% by weight, in other methods less than about 0.4% by weight, in other methods less than about 0.3%, and in more methods about 0.25% or less of the phosphonate diester. In other methods, the compositions herein may comprise about 0.05 wt% or more, or about 0.1 wt% or more, or about 0.15 wt% or more of the phosphonate diester. In embodiments herein, a lubricating oil composition comprising the corrosion inhibitors discussed above maintains a high level of phosphonate diester during aging, and as shown in the examples below, maintains about 10 wt.% or less of monoester phosphonate.

In some methods, the phosphonate diester can have the structure of formula II:

Wherein R ₂ is a C1 to C50 hydrocarbyl chain (preferably a C1 to C30, more preferably a C10 to C20 hydrocarbyl chain) and each R ₃ is independently a C1 to C20 alkyl group, a C1 to C10 alkyl group, or preferably a C1 to C4 alkyl group.

Suitable phosphonic acid diesters may include O, O-di- (primary alkyl) acyclic hydrocarbyl phosphonates wherein the primary alkyl groups are the same or different and each independently contain 1 to 4 carbon atoms, and wherein the acyclic hydrocarbyl group bonded to the phosphorus atom may contain 12 to 30 carbon atoms and is a straight chain hydrocarbyl group free of acetylenic unsaturation. Exemplary compounds include O, O-dimethylhydrocarbyl phosphonate, O-diethylhydrocarbyl phosphonate, O-dipropylhydrocarbyl phosphonate, O-dibutylhydrocarbyl phosphonate, O-diisobutylhydrocarbyl phosphonate and the like, wherein the two alkyl groups are different, such as, for example, O-ethyl-O-methylhydrocarbyl phosphonate, O-butyl-O-propylhydrocarbyl phosphonate and O-butyl-O-isobutylhydrocarbyl phosphonate, wherein the hydrocarbyl groups are in each case linear and saturated or contain one or more olefinic double bonds, each double bond preferably being an internal double bond. Suitable compounds include those in which two O, O-alkyl groups are identical to each other. Other suitable compounds include compounds in which the hydrocarbyl group bonded to the phosphorus atom contains 16 to 20 carbon atoms. A particularly suitable hydrocarbyl phosphonate diester is dimethyl octadecyl phosphonate. Other examples of suitable phosphonic acid diesters include, but are not limited to, dimethyl triacontyl phosphonate, dimethyl eicosanyl phosphonate, dimethyl hexadecyl phosphonate, dimethyl tetradecyl phosphonate, dimethyl hexadecyl phosphonate, dimethyl dodecyl phosphonate, dimethyl dodecenyl phosphonate, and the like.

Base oil

In one method, suitable base oils for the lubricating compositions or gear fluids herein include mineral oils, synthetic oils, and include all common mineral oil base stocks. The mineral oil may be a naphthenic oil or a paraffinic oil. The viscosity of heavy duty or industrial gear oils herein may range from about 5cSt to about 50cSt, or from about 10cSt to about 40cSt, or from about 20cSt to about 40cSt, KV100 (ASTM 445). Mineral oils may be refined by conventional methods using acids, bases and clays or other agents such as aluminum chloride, or may be extracted oils, for example produced by solvent extraction with solvents such as phenol, sulfur dioxide, furfural or dichlorodiethyl ether. The mineral oil may be hydrotreated or hydrofinished, dewaxed by a cooling or catalytic dewaxing process, or hydrocracked, such as from SK Innovation co., ltd (kouol, korea))A series of hydrocracked base oils. Mineral oils may be produced from natural crude sources or consist of isomerized wax material or other residues of refining processes.

The base oil used in the compositions herein or the base oil of lubricating viscosity may be selected from any suitable base oil for transmission or gear oil applications. Examples include base oils in class I-V as specified in the American Petroleum Institute (API) base oil interchangeability guidelines (American Petroleum Institute (API) Base Oil Interchangeability Guidelines). These three types of base oils are as follows:

table 1: base oil type

Class I, class II and class III are mineral oil processing feedstocks that may be preferred for use in the transmission system or gear fluids of the present application. It should be noted that while group III base oils are derived from mineral oils, the rigorous processing that these fluids undergo results in their physical properties very similar to some real synthetic oils, such as PAO. Thus, oils derived from group III base oils may be referred to in the industry as synthetic fluids. Suitable oils may be derived from hydrocracked, hydrogenated, hydrofinished, unrefined, refined and rerefined oils, and mixtures thereof. In some methods, the base oil may be a blend of group I and group II oils, and the blend may be about 0% to about 100% of a group I oil, about 0% to about 100% of a group II oil, about 0% to about 100% of a group III oil, or various blends of group I and group II, group I and group III, or a blend of group II and group III oils.

Unrefined oils are those derived from natural, mineral or synthetic sources with little or no further purification treatment. Refined oils are similar to unrefined oils except they have been treated in one or more purification steps, which may result in an improvement in one or more properties. Examples of suitable purification techniques are solvent extraction, secondary distillation, acid or base extraction, filtration, diafiltration, etc. Oil refined to edible quality may or may not be useful. Edible oils may also be referred to as white oils. In some embodiments, the lubricating oil composition is free of edible oil or white oil.

Rerefined oils are also known as reclaimed or reprocessed oils. These oils are obtained using the same or similar processes as the refined oils. Typically these oils are further processed by techniques directed to the removal of spent additives and oil breakdown products.

The mineral oil may comprise oil obtained by drilling or oil from plants and animals or any mixture thereof. For example, such oils may include, but are not limited to, castor oil, lard oil, olive oil, peanut oil, corn oil, soybean oil and linseed oil, as well as 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. Such oils may be partially or fully hydrogenated if desired. Oils derived from coal or shale may also be suitable.

The plurality of base oils included in the gear fluids herein may be selected from the group consisting of: group I, group II, group III, and combinations of two or more of the foregoing, and wherein the substantial amount of base oil is not the base oil resulting from providing an additive component or viscosity index improver in the composition. In another embodiment, the plurality of base oils included in the lubricating composition may be selected from the group consisting of: group I, group II, and combinations of two or more of the foregoing, and wherein the substantial amount of base oil is not the base oil resulting from providing an additive component or viscosity index improver in the composition.

The base oil may also be any synthetic base oil. Useful synthetic lubricating oils may include hydrocarbon oils such as polymerized, oligomeric, or copolymerized olefins (e.g., polybutenes, polypropylenes, propylene isobutylene copolymers); poly (1-hexene), poly (1-octene), trimers or oligomers of 1-decene, such as poly (1-decene), such materials are commonly referred to as alpha-olefins, and mixtures thereof; alkyl-benzenes (e.g., dodecylbenzene, tetradecylbenzene, dinonylbenzene, di- (2-ethylhexyl) -benzene); polyphenyl (e.g., biphenyl, terphenyl, alkylated polyphenyl); diphenylalkanes, alkylated diphenyl ethers and alkylated diphenyl sulfides and the derivatives, analogs and homologs thereof or mixtures thereof. Polyalphaolefins are typically hydrogenated materials.

Other synthetic lubricating oils include polyol esters, diesters, liquid esters of phosphorus acid (e.g., toluene phosphate, trioctyl phosphate, and diethyl ester of decane phosphonic acid) or polytetrahydrofuran. The synthetic oil may be produced by a Fischer-tropsch reaction (Fischer-Tropschreaction) and may typically be hydroisomerised Fischer-tropsch hydrocarbons or waxes. In one embodiment, the oil may be prepared by a Fischer-Tropsch gas-liquid synthesis procedure, as well as other gas-liquid oils.

In the compositions herein, the amount of base oil of lubricating viscosity may be the balance remaining after subtracting the sum of the amounts of performance additives from 100 wt.%. For example, an oil of lubricating viscosity that may be present in the finished fluid may be a "major amount," such as greater than about 50 wt.%, greater than about 60 wt.%, greater than about 70 wt.%, greater than about 80 wt.%, greater than about 85 wt.%, greater than about 90 wt.%, or greater than about 95 wt.%.

In some methods, a preferred base oil or base oil of lubricating viscosity has less than about 25ppm sulfur, a viscosity index of greater than about 120ppm, and a kinematic viscosity of about 2cSt to about 8cSt at about 100 ℃. In other methods, a base oil of lubricating viscosity has less than about 25ppm sulfur, a viscosity index of greater than 120, and a kinematic viscosity of about 4cSt at 100 ℃. The base oil may have a CP (paraffinic carbon content) of greater than 40%, greater than 45%, greater than 50%, greater than 55%, or greater than 90%. The base oil may have less than 5%, less than 3%, or less than 1% CA (aromatic carbon content). The base oil may have a CN (naphthenic carbon content) of less than 60%, less than 55%, less than 50% or less than 50% and greater than 30%. The base oil may have a ratio of 1-ring naphthenes to 2-6 ring naphthenes of less than 2 or less than 1.5 or less than 1.

Suitable driveline, transmission or gear lubricant compositions herein may comprise additive components within the ranges listed in table 2 below.

Table 2: suitable and preferred transmission system or gear fluid compositions

The percentages of each of the above components represent weight percentages of each component, based on the weight of the total final additive or lubricating oil composition. The remainder of the lubricating oil composition is comprised of one or more base oils or solvents. The additives used to formulate the compositions described herein may be blended into the base oil or solvent, either alone or in various sub-combinations. However, it may be suitable to blend all components simultaneously using an additive concentrate (i.e., an additive plus diluent, such as a hydrocarbon solvent).

The lubricating compositions described herein can be formulated to provide lubrication, enhanced friction properties, and improved copper corrosion for a variety of applications. The driveline lubricating composition herein may be used for lubricating machine parts such as gears. Lubricating fluids according to the present disclosure may be used in gear applications such as industrial gear applications, automotive gear applications, axles, and stationary gearboxes. Gear types may include, but are not limited to, spur gears, helical gears, worm gears, rack gears, involute gears, bevel gears, helical gears, planetary gears, and hypoid gears, as well as limited slip applications and differentials. The driveline lubricating composition disclosed herein is also suitable for use in automatic or manual transmissions, including step-variable automatic transmissions, continuously variable transmissions, semi-automatic transmissions, automatic manual transmissions, toroidal transmissions and dual clutch transmissions. The driveline lubricating compositions herein are particularly useful for axles, transfer cases, differentials, such as straight differentials, steering differentials, limited slip differentials, clutch-type differentials, locking differentials, and the like.

Optional additives

In other methods, lubricants comprising such additives described above may also comprise one or more optional components, provided that such components and amounts thereof do not affect the performance characteristics as described in the preceding paragraphs. These optional components are described in the following paragraphs.

Phosphorus-containing compound

The lubricant compositions herein may comprise one or more phosphorus-containing compounds that may impart antiwear benefits to the fluid. The one or more phosphorus-containing compounds are present in the lubricating oil composition in an amount in the range of from about 0 wt.% to about 15 wt.%, or from about 0.01 wt.% to about 10 wt.%, or from about 0.05 wt.% to about 5 wt.%, or from about 0.1 wt.% to about 3 wt.% of the lubricating oil composition. The phosphorus-containing compound may provide up to 5000ppm phosphorus, or about 50 to about 5000ppm phosphorus, or about 300 to about 1500ppm phosphorus, or up to 600ppm phosphorus, or up to 900ppm phosphorus to the lubricant composition.

The one or more phosphorus-containing compounds may include ashless phosphorus-containing compounds. Examples of suitable phosphorus-containing compounds include, but are not limited to, thiophosphates, dithiophosphates, phosphates, phosphate esters, phosphites, phosphonates, phosphorus-containing carboxylic acid esters, ethers or amide salts thereof and mixtures thereof. Phosphorus-containing antiwear agents are more fully described in European patent 0612839.

It should be noted that the terms phosphonate and phosphite are often used interchangeably in the lubricant industry. For example, dibutyl phosphonate is commonly referred to as dibutyl hydrogen phosphite. It is within the scope of the present invention for the lubricant compositions of the present invention to include a phosphorus-containing compound that may be referred to as a phosphite or phosphonate.

In any of the above phosphorus-containing compounds, the compound may have from about 5wt% to about 20 wt% phosphorus, or from about 5wt% to about 15wt% phosphorus, or from about 8wt% to about 16 wt% phosphorus, or from about 6 wt% to about 9 wt% phosphorus.

The addition of a phosphorus-containing compound in combination with the above-described dispersant to a lubricant composition unexpectedly imparts positive friction characteristics, such as a low coefficient of friction, to the lubricant composition. In some cases, the effect of the present invention is even more pronounced where the phosphorus-containing compound itself imparts negative friction characteristics to the fluid. When these relatively poor friction reducing phosphorus containing compounds are combined with the olefin copolymer dispersants described herein, the lubricant compositions have an improved, i.e., lower coefficient of friction. That is, the dispersants herein tend to convert fluids comprising phosphorus-containing compounds having relatively poor coefficients of friction to fluids having improved friction properties.

This improvement in friction performance of a lubricating composition containing the phosphorus-containing compound and olefin copolymer dispersant described herein is surprising because the friction performance of the fluid is superior to the combination of phosphorus-containing compounds with other types of dispersants, including polyisobutylene succinimide dispersants and olefin copolymer succinimide dispersants that do not have the specified characteristics of the copolymers described above.

Another type of phosphorus-containing compound that imparts improved friction characteristics to lubricating compositions when combined with the olefin copolymer dispersants herein is an ashless (metal-free) phosphorus-containing compound.

In some embodiments, the ashless phosphorus-containing compound may be a dialkyl dithiophosphate, a amyl phosphate, a dipentyl phosphate, a dibutyl hydrogen phosphonate, a dimethyl octadecyl phosphonate, salts thereof, and mixtures thereof.

The ashless phosphorus-containing compound may have the formula:

Wherein R1 is S or O; r2 is-OR, -OH OR-R "; r3 is-OR ", -OH OR SR"' C (O) OH; r4 is-OR "; r' "is a C1-C3 branched or straight alkyl chain; and R' is a C1 to C18 hydrocarbyl chain. When the phosphorus-containing compound has the structure shown in formula XIV, the compound may have about 8 to about 16 weight percent phosphorus.

In some embodiments, the lubricant composition comprises a phosphorus-containing compound of formula XIV, wherein R1 is S; r2 is-OR "; r3 is S R' "COOH; r4 is-OR "; r' "is a C3 branched alkyl chain; r' is C4; and wherein the phosphorus-containing compound is present in an amount to deliver 80ppm to 900ppm of phosphorus to the lubricant composition.

In another embodiment, the lubricant composition comprises a phosphorus-containing compound of formula XIV, wherein R1 is O; r2 is-OH; r3 is-OR' OR-OH; r4 is-OR "; r' is C5; and wherein the phosphorus-containing compound is present in an amount to deliver 80ppm to 1500ppm of phosphorus to the lubricant composition.

In further embodiments, the lubricant composition comprises a phosphorus-containing compound of formula XIV, wherein R1 is O; r2 is OR'; r3 is H; r4 is-OR "; r' is C4; and wherein the one or more phosphorus-containing compounds are present in an amount to deliver 80ppm to 1550ppm of phosphorus to the lubricant composition.

In other embodiments, the lubricant composition comprises a phosphorus-containing compound of formula XIV, wherein R1 is O; r2 is-R'; r3 is-OCH 3 or-OH; r4 is-OCH 3; r' is C18; and wherein the one or more phosphorus-containing compounds are present in an amount to deliver 80ppm to 850ppm of phosphorus to the lubricant composition.

In some embodiments, the phosphorus-containing compound has a structure represented by formula XIV and delivers from about 80ppm to about 4500ppm phosphorus to the lubricant composition. In other embodiments, the phosphorus-containing compound is present in an amount to deliver from about 150ppm to about 1500ppm phosphorus, or from about 300ppm to about 900ppm phosphorus, or from about 800ppm to 1600ppm phosphorus, or from about 900ppm to about 1800ppm phosphorus to the lubricant composition.

Antiwear agent

The lubricant composition may also contain other antiwear agents that are phosphorus-free compounds. Examples of such antiwear agents include borates, borate epoxides, thiocarbamate compounds (including thiocarbamates, alkylene-coupled thiocarbamates and bis (S-alkyl dithiocarbamoyl) disulfides, thiocarbamate amides, thiocarbamate ethers, alkylene-coupled thiocarbamates and bis (S-alkyl dithiocarbamoyl) disulfides and mixtures thereof), sulfurized olefins, tridecyl adipates, titanium compounds and long chain derivatives of hydroxycarboxylic acids such as tartrate derivatives, tartaric acid amides, tartaric acid imides, citrates and mixtures thereof. A suitable thiocarbamate compound is molybdenum dithiocarbamate. Suitable tartrate derivatives or tartrimides may contain alkyl ester groups, wherein the total number of carbon atoms on the alkyl groups may be at least 8. The tartrate derivative or tartrimide may contain alkyl ester groups, wherein the total number of carbon atoms on the alkyl groups may be at least 8. In one embodiment, the antiwear agent may comprise a citrate ester. The additional antiwear agent may be present in a range including from about 0 wt.% to about 15 wt.%, or from about 0.01 wt.% to about 10 wt.%, or from about 0.05 wt.% to about 5 wt.%, or from about 0.1 wt.% to about 3 wt.% of the lubricating oil composition.

Extreme pressure agent

The lubricant compositions of the present disclosure may also contain other extreme pressure agents as long as the lubricating compositions herein include the noted amounts and distributions described herein. The optional extreme pressure agent may contain sulfur and may contain at least 12 wt.% sulfur. In some embodiments, the extreme pressure agent added to the lubricating oil is sufficient to provide at least 350ppm sulfur, 500ppm sulfur, 760ppm sulfur, about 350ppm to about 2,000ppm sulfur, about 2,000ppm to about 30,000ppm sulfur, or about 2,000ppm to about 4,800ppm sulfur, or about 4,000ppm to about 25,000ppm sulfur to the lubricant composition.

A variety of sulfur-containing extreme pressure agents are suitable and include sulfurized animal or vegetable fats or oils, sulfurized animal or vegetable fatty acid esters, fully or partially esterified esters of trivalent or pentavalent acids of phosphorus, sulfurized olefins (see, e.g., U.S. Pat. nos. 2,995,569;3,673,090;3,703,504;3,703,505;3,796,661;3,873,454 4,119,549;4,119,550;4,147,640;4,191,659;4,240,958;4,344,854;4,472,306; and 4,711,736), dihydrocarbyl polysulfides (see, e.g., U.S. Pat. nos. 2,237,625;2,237,627;2,527,948;2,695,316;3,022,351;3,308,166;3,392,201;4,564,709; and uk 1,162,334), functionally substituted dihydrocarbyl polysulfides (see, e.g., U.S. Pat. No. 4,218,332), and polysulfide olefin products (see, e.g., U.S. Pat. No. 4,795,576). Other suitable examples include organic sulfur compounds selected from the group consisting of sulfurized olefins, sulfur-containing amino heterocyclic compounds, 5-dimercapto-1, 3, 4-thiadiazoles, polysulfides having a majority of S3 and S4 sulfides, sulfurized fatty acids, sulfurized branched olefins, organic polysulfides, and mixtures thereof.

In some embodiments, the extreme pressure agent is present in the lubricating composition in an amount of up to about 3.0 wt.%, or up to about 5.0 wt.%. In other embodiments, the extreme pressure agent is present at about 0.05 wt.% to about 0.5 wt.% based on the total lubricant composition. In other embodiments, the extreme pressure agent is present at about 0.1 wt.% to about 3.0 wt.% based on the total lubricant composition. In other embodiments, the extreme pressure agent is present in an amount of about 0.6 wt.% to about 1 wt.% based on the total lubricant composition. In further embodiments, the detergent is present in an amount of about 1.0 wt.% based on the total lubricant composition.

One class of suitable extreme pressure agents are polysulfides consisting of one or more compounds of the formula: ra-Sx-Rb, where Ra and Rb are hydrocarbyl groups, each hydrocarbyl group may contain from 1 to 18 and in other processes from 3 to 18 carbon atoms, and x may be in the range of from 2 to 8, typically in the range of from 2 to 5, especially 3. In certain methods, x is an integer from 3 to 5, wherein 30% to 60% of x is an integer of 3 or 4. The hydrocarbyl groups may be of a wide variety of types, such as alkyl, cycloalkyl, alkenyl, aryl, or aralkyl. Tertiary alkyl polysulfides, such as di-t-butyl trisulfide, and mixtures comprising di-t-butyl trisulfide (e.g., mixtures consisting essentially or entirely of tri-, tetra-and penta-sulfides) may be used. Examples of other useful dihydrocarbyl polysulfides include dipentyl polysulfides, dinonyl polysulfides, dodecyl polysulfides, and dibenzyl polysulfides.

Another suitable class of extreme pressure agents are sulfurized isobutylene produced by reacting an olefin such as isobutylene with sulfur. The Sulfurized Isobutylene (SIB), particularly sulfurized polyisobutylene, typically has a sulfur content of about 10% to about 55%, desirably about 30% to about 50% by weight. A variety of other olefins or unsaturated hydrocarbons, such as isobutylene dimers or trimers, may be used to form the sulfurized olefin extreme pressure agent. Various processes for preparing sulfurized olefins have been disclosed in the prior art. See, for example, U.S. patent number 3,471,404 to Myers; U.S. patent No. 4,204,969 to Papay et al; U.S. patent No. 4,954,274 to Zaweski et al; U.S. patent No. 4,966,720 to DeGonia et al; and U.S. patent No. 3,703,504 to Horodysky et al, each of which is incorporated herein by reference.

Methods for preparing sulfurized olefins, including those disclosed in the above-identified patents, generally include forming a material commonly referred to as an "adduct" in which an olefin is reacted with a sulfur halide, such as sulfur monochloride. The adduct is then reacted with a sulfur source to provide a sulfurized olefin. The quality of the sulfurized olefin is typically measured by various physical properties including, for example, viscosity, sulfur content, halogen content, and copper corrosion test weight loss. U.S. patent No. 4,966,720 relates to sulfurized olefins for use as extreme pressure additives in lubricating oils and to two-step reactions for their preparation.

Antioxidant agent

The lubricating oil compositions herein may also optionally contain one or more antioxidants. Antioxidant compounds are known and include, for example, phenoxide sulfide, sulfurized olefin, phosphosulfurized terpene, sulfurized ester, aromatic amine, alkylated diphenylamine (e.g., nonyldiphenylamine, dinonyldiphenylamine, octyldiphenylamine, dioctyldiphenylamine), phenyl-alpha-naphthylamine, alkylated phenyl-alpha-naphthylamine, hindered non-aromatic amines, phenol, hindered phenol, oil soluble molybdenum compounds, macromolecular antioxidants, or mixtures thereof. The antioxidant compounds may be used alone or in combination.

The hindered phenolic antioxidants may contain sec-butyl and/or tert-butyl groups as sterically hindered groups. The phenolic group may be further substituted with a hydrocarbyl group and/or a bridging group attached to the second aromatic group. Examples of suitable hindered phenol antioxidants include 2, 6-di-tert-butylphenol, 4-methyl-2, 6-di-tert-butylphenol, 4-ethyl-2, 6-di-tert-butylphenol, 4-propyl-2, 6-di-tert-butylphenol or 4-butyl-2, 6-di-tert-butylphenol, or 4-dodecyl-2, 6-di-tert-butylphenol. In one embodiment, the hindered phenol antioxidant may be an ester and may include, for example, those commercially available from BASFL-135 or an addition product derived from 2, 6-di-tert-butylphenol and an alkyl acrylate wherein the alkyl group may comprise from about 1 to about 18, or from about 2 to about 12, or from about 2 to about 8, or from about 2 to about 6, or about 4 carbon atoms. Another commercially available hindered phenol antioxidant may be an ester and may include the one available from EarMich (Albemarle Corporation)4716。

Useful antioxidants may include diarylamines and phenols. In one embodiment, the lubricating oil composition may contain a mixture of diarylamines and phenols, such that each antioxidant may be present in an amount sufficient to provide up to about 5 wt.%, based on the weight of the lubricant composition. In one embodiment, the antioxidant may be a mixture of about 0.3 wt.% to about 1.5 wt.% diarylamine and about 0.4 wt.% to about 2.5 wt.% phenol, based on the lubricant composition.

Examples of suitable olefins that can be sulfided to form a sulfided olefin include propylene, butene, isobutylene, polyisobutylene, pentene, hexene, heptene, octene, nonene, decene, undecene, dodecene, tridecene, tetradecene, pentadecene, hexadecene, heptadecene, octadecene, nonadecene, eicosene, or mixtures thereof. In one embodiment, hexadecene, heptadecene, octadecene, nonadecene, eicosene, or mixtures thereof, and dimers, trimers, and tetramers thereof are particularly suitable olefins. Alternatively, the olefin may be a Diels-alder adduct (Diels-Alder adduct) of a diene, such as 1, 3-butadiene, with an unsaturated ester, such as butyl acrylate.

Another class of sulfurized olefins includes sulfurized fatty acids and esters thereof. Fatty acids are typically obtained from vegetable or animal oils and typically contain from about 4 to about 22 carbon atoms. Examples of suitable fatty acids and esters thereof include triglycerides, oleic acid, linoleic acid, palmitoleic acid, or mixtures thereof. Typically, the fatty acid is obtained from lard, pine oil, peanut oil, soybean oil, cottonseed oil, sunflower oil, or mixtures thereof. The fatty acids and/or esters may be mixed with olefins, such as alpha-olefins.

The one or more antioxidants may be present in the range of about 0 wt.% to about 20 wt.%, or about 0.1 wt.% to about 10 wt.%, or about 1 wt.% to about 5 wt.% of the lubricating oil composition.

Dispersing agent

The dispersant contained in the lubricant composition may include, but is not limited to, an oil-soluble polymeric hydrocarbon backbone having functional groups capable of associating with the particles to be dispersed. Typically, dispersants comprise amine, alcohol, amide or ester polar moieties attached to the polymer backbone, typically via bridging groups. The dispersant may be selected from the mannich dispersants as described in U.S. Pat. nos. 3,634,515, 3,697,574 and 3,736,357; ashless succinimide dispersants as described in U.S. Pat. nos. 4,234,435 and 4,636,322; amine dispersants as described in U.S. Pat. nos. 3,219,666, 3,565,804, and 5,633,326; koch dispersants as described in U.S. patent nos. 5,936,041, 5,643,859, and 5,627,259, and as described in U.S. patent No. 5,851,965;5,853,434; and 5,792,729.

In some embodiments, the additional dispersant may be derived from poly-alpha-olefin (PAO) succinic anhydride, olefin maleic anhydride copolymers. As one example, the additional dispersant may be described as poly-PIBSA. In another embodiment, the additional dispersant may be derived from an anhydride grafted with an ethylene-propylene copolymer. Another additional dispersant may be a high molecular weight ester or half ester amide.

Dispersants are commonly referred to as ashless dispersants because they do not contain ash forming metals prior to mixing into the lubricating oil composition and they typically do not provide any ash when added to a lubricant. Ashless dispersants are characterized by a polar group attached to a relatively higher molecular weight hydrocarbon chain. Typical ashless dispersants comprise an N-substituted long chain alkenyl succinimide. Examples of N-substituted long chain alkenyl succinimides include polyisobutylene succinimides, where the number average molecular weight of the polyisobutylene substituent is in the range of about 350 to about 50,000 or to about 5,000 or to about 3,000 as measured by GPC. Succinimide dispersants and their preparation are disclosed, for example, in U.S. patent No. 7,897,696 or U.S. patent No. 4,234,435. Alkenyl substituents may be prepared from polymerizable monomers containing from about 2 to about 16, or from about 2 to about 8, or from about 2 to about 6 carbon atoms. Succinimide dispersants are typically imides formed from polyamines, typically poly (ethyleneamines).

Preferred amines are selected from polyamines and hydroxylamines. Examples of polyamines that may be used include, but are not limited to, diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), and higher homologs such as Pentaethylenehexamine (PEHA), and the like.

Suitable heavy polyamines are mixtures of polyalkylene-polyamines comprising small amounts of lower polyamine oligomers such as TEPA and PEHA (pentaethylenehexamine) but mainly oligomers having 6 or more nitrogen atoms, 2 or more primary amines and more extensive branching than conventional polyamine mixtures.

In some processes, suitable polyamines are commonly referred to as PAM and contain a mixture of ethyleneamines, with TEPA and Pentaethylenehexamine (PEHA) being the major portions of the polyamines, typically less than about 80%.

Typically, PAM has from 8.7 to 8.9 milliequivalents of primary amine per gram (equivalent weight of 115 grams to 112 grams per equivalent of primary amine) and a total nitrogen content of about 33 wt.% to 34 wt.%. The heavy fraction, which has little TEPA and contains only a very small amount of PEHA but mainly PAM oligomers with more than 6 nitrogen and more broadly branched oligomers, can produce dispersants with improved dispersion.

In one embodiment, the present disclosure further comprises at least one polyisobutylene succinimide dispersant derived from polyisobutylene having a number average molecular weight in the range of about 350 to about 50,000 or to about 5000 or to about 3000, as determined by GPC. The polyisobutene succinimide may be used alone or in combination with other dispersants.

In some embodiments, the polyisobutylene (when included) may have a terminal double bond content of greater than 50 mole%, greater than 60 mole%, greater than 70 mole%, greater than 80 mole%, or greater than 90 mole%. Such PIB is also known as highly reactive PIB ("HR-PIB"). HR-PIB having a number average molecular weight in the range of about 800 to about 5000 as determined by GPC is suitable for embodiments of the present disclosure. Conventional PIB typically has a terminal double bond content of less than 50 mole%, less than 40 mole%, less than 30 mole%, less than 20 mole%, or less than 10 mole%.

HR-PIB having a number average molecular weight in the range of about 900 to about 3000 as determined by GPC may be suitable. Such HR-PIBs are commercially available or can be synthesized by polymerizing isobutylene in the presence of a non-chlorinated catalyst, such as boron trifluoride, as described in U.S. patent No. 4,152,499 to Boerzel et al and U.S. patent No. 5,739,355 to Gateau et al. When used in the aforementioned thermal ene reactions, HR-PIB can increase conversion in the reaction, as well as reduce sediment formation, due to enhanced reactivity. Suitable methods are described in U.S. patent No. 7,897,696.

In one embodiment, the present disclosure further comprises at least one dispersant derived from polyisobutylene succinic anhydride ("PIBSA"). PIBSA may have an average succinic acid moiety per polymer of between about 1.0 and about 2.0.

Chromatographic techniques can be used to determine the% activity of alkenyl or alkyl succinic anhydrides. Such a method is described in columns 5 and 6 of U.S. patent No. 5,334,321. The percent conversion of polyolefin was calculated from the% activity using the equations in columns 5 and 6 of U.S. patent No. 5,334,321.

In one embodiment, the dispersant may be derived from Polyalphaolefin (PAO) succinic anhydride. In one embodiment, the dispersant may be derived from an olefin maleic anhydride copolymer. For example, the dispersant may be described as poly PIBSA. In embodiments, the dispersant may be derived from an anhydride grafted to an ethylene-propylene copolymer.

A suitable class of nitrogen-containing dispersants may be derived from Olefin Copolymers (OCP), more particularly ethylene-propylene dispersants, which may be grafted with maleic anhydride. A more complete list of nitrogen-containing compounds that can react with functionalized OCPs is described in U.S. patent No. 7,485,603;7,786,057;7,253,231;6,107,257; and 5,075,383; and/or are commercially available.

One class of suitable dispersants may also be Mannich bases (Mannich base). Mannich bases are materials formed from the condensation of higher molecular weight alkyl-substituted phenols, polyalkylene polyamines, and aldehydes (such as formaldehyde). Mannich bases are described in more detail in U.S. Pat. No. 3,634,515.

One class of suitable dispersants may also be high molecular weight esters or half-ester amides. Suitable dispersants may also be post-treated by conventional methods by reaction with any of a variety of agents. Among these are boron, urea, thiourea, dimercaptothiadiazoles, carbon disulphide, aldehydes, ketones, carboxylic acids, hydrocarbon-substituted succinic anhydrides, maleic anhydride, nitriles, epoxides, carbonates, cyclic carbonates, hindered phenolic esters, and phosphorus compounds. US 7,645,726; US 7,214,649; and US 8,048,831 are incorporated herein by reference in their entirety.

In addition to carbonate and boric acid post-treatments, both compounds may be post-treated or further post-treated using a variety of post-treatments designed to improve or impart different properties. Such post-treatments include those outlined in columns 27 to 29 of U.S. patent No. 5,241,003, incorporated herein by reference. Such treatments include the following: inorganic phosphorous acid or anhydrous (e.g., U.S. Pat. nos. 3,403,102 and 4,648,980); an organic phosphorus compound (e.g., U.S. patent No. 3,502,677); phosphorus pentasulfide; boron compounds as already mentioned above (e.g., U.S. Pat. nos. 3,178,663 and 4,652,387); carboxylic acids, polycarboxylic acids, anhydrides, and/or acid halides (e.g., U.S. Pat. nos. 3,708,522 and 4,948,386); epoxides, polyepoxides, or thioepoxides (e.g., U.S. Pat. nos. 3,859,318 and 5,026,495); aldehydes or ketones (e.g., U.S. patent number 3,458,530); carbon disulfide (e.g., U.S. Pat. No. 3,256,185); glycidol (e.g., U.S. patent No. 4,617,137); urea, thiourea or guanidine (e.g. U.S. Pat. nos. 3,312,619;3,865,813; and british patent GB 1,065,595); organic sulfonic acids (e.g., U.S. patent No. 3,189,544 and british patent GB 2,140,811); alkenyl cyanide (e.g., U.S. patent nos. 3,278,550 and 3,366,569); diketene (e.g., U.S. patent No. 3,546,243); diisocyanates (e.g., U.S. Pat. No. 3,573,205); alkane sultones (e.g., U.S. patent No. 3,749,695); 1, 3-dicarbonyl compounds (e.g., U.S. Pat. No. 4,579,675); sulfates of alkoxylated alcohols or phenols (e.g., U.S. patent No. 3,954,639); cyclic lactones (e.g., U.S. Pat. nos. 4,617,138;4,645,515;4,668,246;4,963,275; and 4,971,711); cyclic carbonates or thiocarbonates linear mono-carbonates or polycarbonates, or chloroformates (e.g., U.S. Pat. Nos. 4,612,132;4,647,390;4,648,886;4,670,170); nitrogen-containing carboxylic acids (e.g., U.S. patent No. 4,971,598 and british patent GB 2,140,811); hydroxy-protected chlorodicarbonyloxy compounds (e.g., U.S. patent No. 4,614,522); lactam, sultam, thiolactone, or dithiolactone (e.g., U.S. Pat. nos. 4,614,603 and 4,666,460); cyclic carbonates or thiocarbonates linear mono-carbonates or polycarbonates, or chloroformates (e.g., U.S. Pat. Nos. 4,612,132;4,647,390;4,646,860; and 4,670,170); nitrogen-containing carboxylic acids (e.g., U.S. patent No. 4,971,598 and british patent GB 2,440,811); hydroxy-protected chlorodicarbonyloxy compounds (e.g., U.S. patent No. 4,614,522); lactam, sultam, thiolactone, or dithiolactone (e.g., U.S. Pat. nos. 4,614,603 and 4,666,460); cyclic carbamates, cyclic thiocarbamates or cyclic dithiocarbamates (e.g., U.S. Pat. nos. 4,663,062 and 4,666,459); hydroxy aliphatic carboxylic acids (e.g., U.S. Pat. Nos. 4,482,464;4,521,318;4,713,189); oxidizing agents (e.g., U.S. patent No. 4,379,064); a combination of phosphorus pentasulfide and a polyalkylene polyamine (e.g., U.S. patent No. 3,185,647); a combination of a carboxylic acid or aldehyde or ketone and sulfur or sulfur chloride (e.g., U.S. Pat. Nos. 3,390,086;3,470,098); a combination of hydrazine and carbon disulfide (e.g., U.S. patent number 3,519,564); combinations of aldehydes and phenols (e.g., U.S. Pat. Nos. 3,649,229;5,030,249;5,039,307); a combination of an aldehyde and an O-diester of dithiophosphoric acid (e.g., U.S. patent No. 3,865,740); a combination of hydroxy aliphatic carboxylic acid and boric acid (e.g., U.S. patent No. 4,554,086); hydroxy aliphatic carboxylic acid, then formaldehyde and phenol (e.g., U.S. Pat. No. 4,636,322); a combination of a hydroxy aliphatic carboxylic acid and then an aliphatic dicarboxylic acid (e.g., U.S. patent No. 4,663,064); formaldehyde and phenol in combination with then glycolic acid (e.g., U.S. patent No. 4,699,724); a hydroxy aliphatic carboxylic acid or oxalic acid, and then a combination of diisocyanates (e.g., U.S. patent No. 4,713,191); a combination of a phosphorus mineral acid or anhydride or a partial or complete sulfur analog with a boron-containing compound (e.g., U.S. Pat. No. 4,857,214); a combination of an organic diacid, then an unsaturated fatty acid, and then a nitrosoaromatic amine, optionally followed by a boron compound, and then an glycolysis reagent (e.g., U.S. patent No. 4,973,412); a combination of an aldehyde and a triazole (e.g., U.S. patent number 4,963,278); aldehyde and triazole, then boron compounds (e.g., U.S. patent No. 4,981,492); a combination of a cyclic lactone and a boron compound (e.g., U.S. Pat. nos. 4,963,275 and 4,971,711). The above-mentioned patents are incorporated herein in their entirety.

The TBN of a suitable dispersant may be from about 10mg to about 65mg KOH/g dispersant on an oil-free basis, equivalent to about 5TBN to about 30TBN if measured on a dispersant sample containing about 50% diluent oil. TBN was measured by the method of ASTM D2896.

In further embodiments, the optional dispersant additive may be a hydrocarbyl-substituted succinamide or succinimide dispersant. In the method, the hydrocarbyl-substituted succinamide or succinimide dispersant is derived from a hydrocarbyl-substituted acylating agent reacted with a polyalkylene polyamine, and wherein the hydrocarbyl substituent of the succinamide or succinimide dispersant is a linear or branched hydrocarbyl group having a number average molecular weight of about 250 to about 5,000 as measured by GPC using polystyrene as a calibration reference.

In some methods, the polyalkylene polyamine used to form the dispersant has the formula

Wherein each R and R' is independently a divalent C1 to C6 alkylene linking group, each R ₁ and R ₂ is independently hydrogen, C1 to C6 alkyl, or together with the nitrogen atom to which they are attached form a 5 or 6 membered ring optionally fused with one or more aromatic or non-aromatic rings, and n is an integer between 0 and 8. In other methods, the polyalkylene polyamine is selected from the group consisting of: mixtures of polyethylene polyamines having an average of 5 to 7 nitrogen atoms, triethylenetetramine, tetraethylenepentamine, and combinations thereof.

The dispersant, if present, may be used in an amount sufficient to provide up to about 20 wt.%, based on the final weight of the lubricating oil composition. Another amount of dispersant that may be used may be from about 0.1 wt.% to about 15 wt.%, or from about 0.1 wt.% to about 10 wt.%, or from about 0.1 wt.% to about 8 wt.%, or from about 1 wt.% to about 10 wt.%, or from about 1 wt.% to about 8 wt.%, or from about 1 wt.% to about 6 wt.%, based on the final weight of the lubricating oil composition. In some embodiments, the lubricating oil composition utilizes a mixed dispersant system. A single type of dispersant or a mixture of two or more types of dispersants in any desired ratio may be used.

The dispersant, if present, may be used in an amount sufficient to provide up to about 10 wt.%, based on the final weight of the lubricating oil composition. Another amount of dispersant that may be used may be from about 0.1 wt.% to about 10 wt.%, or from about 3 wt.% to about 8 wt.%, or from about 1 wt.% to about 6 wt.%, based on the final weight of the lubricating oil composition.

Viscosity index improver

The lubricant compositions herein may also optionally contain one or more viscosity index improvers. Suitable viscosity index improvers may comprise polyolefins, olefin copolymers, ethylene/propylene copolymers, polyisobutylene, hydrogenated styrene-isoprene polymers, styrene/maleate copolymers, hydrogenated styrene/butadiene copolymers, hydrogenated isoprene polymers, alpha-olefin maleic anhydride copolymers, polymethacrylates, polyacrylates, polyalkylstyrenes, hydrogenated alkenyl aryl conjugated diene copolymers, or mixtures thereof. Other viscosity index improvers may include star polymers, and suitable examples are described in U.S. publication No. 20120101017A1, which is incorporated herein by reference.

The lubricating oil compositions herein may optionally contain one or more dispersant viscosity index improvers in addition to or in place of the viscosity index improvers. Suitable viscosity index improvers may include functionalized polyolefins, such as ethylene-propylene copolymers that have been functionalized with the reaction product of an acylating agent (such as maleic anhydride) and an amine; an amine-functionalized polymethacrylate, or an esterified maleic anhydride-styrene copolymer reacted with an amine.

The total amount of viscosity index improver and/or dispersant viscosity index improver may be from about 0 wt.% to about 20 wt.%, from about 0.1 wt.% to about 15 wt.%, from about 0.1 wt.% to about 12 wt.%, or from about 0.5 wt.% to about 10 wt.%, from about 3 wt.% to about 20 wt.%, from about 3 wt.% to about 15 wt.%, from about 5 wt.% to about 15 wt.%, or from about 5 wt.% to about 10 wt.% of the lubricating oil composition.

In some embodiments, the viscosity index improver is a polyolefin or olefin copolymer having a number average molecular weight of from about 10,000 to about 500,000, from about 50,000 to about 200,000, or from about 50,000 to about 150,000. In some embodiments, the viscosity index improver is a hydrogenated styrene/butadiene copolymer having a number average molecular weight of about 40,000 to about 500,000, about 50,000 to about 200,000, or about 50,000 to about 150,000. In some embodiments, the viscosity index improver is a polymethacrylate having a number average molecular weight of about 10,000 to about 500,000, about 50,000 to about 200,000, or about 50,000 to about 150,000.

Other optional additives

Other additives may be selected to perform one or more functions desired for the lubricating composition. In addition, one or more of the mentioned additives may be multifunctional and provide functionality other than or different from the functionality specified herein. The other additives may be additives other than the specified additives of the present disclosure and/or may comprise one or more of the following: metal deactivators, viscosity index improvers, ashless TBN accelerators, anti-wear agents, corrosion inhibitors, rust inhibitors, dispersants, dispersant viscosity index improvers, extreme pressure agents, antioxidants, foam inhibitors, demulsifiers, emulsifiers, pour point depressants, seal swelling agents, and mixtures thereof. Typically, a fully formulated lubricating oil will contain one or more of these additives.

Suitable metal deactivators may include derivatives of benzotriazole (typically tolyltriazole), dimercaptothiadiazole derivatives, 1,2, 4-triazole, benzimidazole, 2-alkyldithiobenzimidazole or 2-alkyldithiobenzothiazole; foam inhibitors, including copolymers of ethyl acrylate and 2-ethylhexyl acrylate, and optionally vinyl acetate; demulsifiers including trialkyl phosphates, polyethylene glycols, polyethylene oxides, polypropylene oxides and (ethylene oxide-propylene oxide) polymers; pour point depressants, including esters of maleic anhydride-styrene, polymethacrylates, polyacrylates or polyacrylamides.

Suitable foam inhibitors include silicon-based compounds such as siloxanes.

Suitable pour point depressants may include polymethyl methacrylate or mixtures thereof. The pour point depressant may be present in an amount sufficient to provide from about 0 wt.% to about 1 wt.%, from about 0.01 wt.% to about 0.5 wt.%, or from about 0.02 wt.% to about 0.04 wt.%, based on the final weight of the lubricating oil composition.

Suitable rust inhibitors may be single compounds or mixtures of compounds having the property of inhibiting corrosion of the iron metal surface. Non-limiting examples of rust inhibitors useful herein include: oil-soluble high molecular weight organic acids such as 2-ethylhexanoic acid, lauric acid, myristic acid, palmitic acid, oleic acid, linoleic acid, linolenic acid, behenic acid, and cerotic acid; and oil-soluble polycarboxylic acids including dimer and trimer acids, such as those produced from pine oil fatty acids, oleic acid, and linoleic acid. Other suitable corrosion inhibitors include long chain alpha, omega-dicarboxylic acids having a molecular weight in the range of about 600 to about 3000, and alkenyl succinic acids in which the alkenyl group contains about 10 or more carbon atoms, such as tetrapropenyl succinic acid, tetradecenyl succinic acid, and hexadecenyl succinic acid. Another useful type of acidic corrosion inhibitor is a half ester of alkenyl succinic acid having from about 8 to about 24 carbon atoms in the alkenyl group with an alcohol, such as polyethylene glycol. Corresponding semi-amides of such alkenyl succinic acids are also useful. Useful rust inhibitors are high molecular weight organic acids. In some embodiments, the engine oil is free of rust inhibitors.

The rust inhibitor, if present, may be used in an optional amount sufficient to provide from about 0wt.% to about 5 wt.%, from about 0.01 wt.% to about 3wt.%, from about 0.1 wt.% to about 2 wt.%, based on the final weight of the lubricating oil composition.

The lubricant composition may also include a corrosion inhibitor (note that some of the other mentioned components may also have copper corrosion inhibiting properties). Suitable copper corrosion inhibitors include etheramines, polyethoxylated compounds such as ethoxylated amines and alcohols, imidazolines, mono-and dialkyl thiadiazoles, and the like.

Thiazole, triazole and thiadiazole are also useful in lubricants. Examples include benzotriazole, tolyltriazole, octyltriazole, decyltriazole; dodecyl triazole, 2-mercaptobenzotriazole, 2, 5-dimercapto-1, 3, 4-thiadiazole, 2-mercapto-5-alkylthio-1, 3, 4-thiadiazole and 2-mercapto-5-alkylthio-1, 3, 4-thiadiazole. In one embodiment, the lubricant composition comprises a1, 3, 4-thiadiazole, such as a 2-hydrocarbyl dithio-5-mercapto-1, 3, 4-dithiadiazole.

Defoamers/surfactants may also be included in the fluid according to the present invention. Various reagents are known for this purpose. Copolymers of ethyl acrylate and hexyl acrylate may be used, such as PC-1244 available from the company nux-vomica (Solutia). In other embodiments, silicone fluids, such as 4% DCF, may be included. Mixtures of defoamers may also be present in the lubricant composition.

Examples

The following examples are illustrative of exemplary embodiments of the present disclosure. In these examples, and elsewhere in the present application, all ratios, parts, and percentages are by weight unless otherwise specified. These examples are intended to be presented for illustrative purposes only and are not intended to limit the scope of the application disclosed herein.

Comparative example 1

Comparative corrosion inhibitors comprising a mixture of dialkyl-thiadiazole compounds and monoalkyl-thiadiazole compounds were prepared as follows: 43.3% sodium 2, 5-dimercapto-1, 3, 4-thiadiazole solution (NaDMTD, 504.0g,1.267 moles), 98.7% t-nonylthiol (334.0 g,2.059 moles) and 95% sulfuric acid (77.8 g,0.75 moles) were charged to a2 liter kettle equipped with baffles, condenser and gas outlet connected to a caustic/bleach scrubber. To this mixture was added 50% hydrogen peroxide (144.4 g,2.123 moles) over 3 hours 50 minutes at a temperature of about 75 ℃ to about 85 ℃. The reaction temperature is then raised to about 90 ℃ and the aqueous layer is separated, followed by vacuum stripping at a temperature of about 110 ℃ or less.

The reaction had a total reaction molar ratio of 1.624 molar equivalents of alkyl mercaptan to thiadiazole and 1.675 molar equivalents of hydrogen peroxide to thiadiazole, resulting in a 1:1.62:1.68 thiadiazole to thiol to peroxide. The Total Acid Number (TAN) of this sample was about 30.6 and the final product contained a 74.3:25.4 molar ratio of dialkyl-thiadiazole to monoalkyl-thiadiazole, as measured by C NMR.

Comparative example 2

Comparative corrosion inhibitors were prepared as follows: 43.3% sodium 2, 5-dimercapto-1, 3, 4-thiadiazole (NaDMTD, 447.6g,1.125 mol), 98.7% tertiary nonylthiol (413.0 g,2.546 mol) and 95% sulfuric acid (70.5 g,0.68 mol) were charged into a 2 liter kettle equipped with a baffle, condenser and gas outlet connected to a caustic/bleach scrubber. To this mixture was added 50% hydrogen peroxide (198.0 g,2.912 moles). The reaction temperature is then raised to about 90 ℃ and the aqueous layer is separated, followed by vacuum stripping at a temperature of about 110 ℃ or less.

The reaction had a total reaction molar ratio of 1:2.26:2.59 thiadiazole to thiol to peroxide of 2.262 molar equivalents of alkyl thiol to thiadiazole and 2.587 molar equivalents of hydrogen peroxide to thiadiazole. The Total Acid Number (TAN) of this sample was about 22 and the final product had a molar ratio of dialkyl-thiadiazole to monoalkyl-thiadiazole of greater than 91:9 as measured by C NMR.

Example 1

The corrosion inhibitors of the present invention comprising predominantly dialkyl-thiadiazole compounds are prepared as follows: 43.3% sodium 2, 5-dimercapto-1, 3, 4-thiadiazole solution (NaDMTD, 447.6g,1.125 mol), 98.7% t-nonylthiol (386.0 g,2.379 mol) and 95% sulfuric acid (69.1 g,0.70 mol) were charged into a 2 liter kettle equipped with a baffle, condenser and gas outlet connected to a caustic/bleach scrubber. To this mixture was added 50% hydrogen peroxide (167.3 g,2.460 moles) over 3 hours 50 minutes at a temperature of about 75 ℃ to about 85 ℃. The reaction temperature is then raised to about 90 ℃ and the aqueous layer is separated, followed by vacuum stripping at a temperature of about 110 ℃ or less.

The reaction had 2.113 molar equivalents of alkyl mercaptan to thiadiazole and 2.186 molar equivalents of hydrogen peroxide to thiadiazole, resulting in a total reaction molar ratio of thiadiazole to thiol to peroxide of 1:2.11:2.19. The Total Acid Number (TAN) of the sample was about 8 and the final product had undetectable levels of monoalkylthiadiazole compound, as measured by C NMR, the molar ratio of dialkyl-thiadiazole to monoalkyl-thiadiazole was greater than 99:1.

Example 2

Another corrosion inhibitor of the present invention comprising mainly a dialkyl-thiadiazole compound is prepared as follows: 43.3% aqueous 2, 5-dimercapto-1, 3, 4-thiadiazole sodium solution (NaDMTD, 500g,1.257 moles), 98.7% t-nonylthiol (408.7 g,2.519 moles) and 95% sulfuric acid (74.1 g,0.72 moles) were charged into a2 liter kettle equipped with a baffle, condenser and gas outlet connected to a caustic/bleach scrubber. To this mixture was added 50% hydrogen peroxide (188.5 g,2.772 moles) over 3 hours 50 minutes at a temperature of about 75 ℃ to about 85 ℃. After addition of thiol/peroxide, a sample was removed and the Total Acid Number (TAN) was measured to be less than about 10. The reaction temperature was raised to 90 ℃ and the aqueous layer was separated, followed by vacuum stripping at a temperature of about 110 ℃ or less.

The reaction had a total reaction molar ratio of 1:2.00:2.21 of thiadiazole to thiol to peroxide of 2.004 molar equivalents of alkyl thiol to thiadiazole and 2.205 molar equivalents of peroxide factor to thiadiazole. The Total Acid Number (TAN) of the sample was about 8 and the final product had undetectable levels of monoalkylthiadiazole compound, as measured by C NMR, the molar ratio of dialkyl-thiadiazole to monoalkyl-thiadiazole was greater than 99:1.

Example 3

Another corrosion inhibitor of the present invention comprising mainly a dialkyl-thiadiazole compound is prepared as follows: 43.3% aqueous sodium 2, 5-dimercapto-1, 3, 4-thiadiazole (NaDMTD, 160g,0.402 mole), 98.7% t-nonylthiol (127.2 g,0.874 mole) and 95% sulfuric acid (23.5 g,0.228 mole) were charged to a2 liter kettle equipped with baffles, condenser and gas outlet connected to a caustic/bleach scrubber. To this mixture was added 50% hydrogen peroxide (59.8 g,0.879 mole) over 3 hours and 50 minutes at a temperature of about 75 ℃ to about 85 ℃. After addition of thiol/peroxide, a sample was removed and the Total Acid Number (TAN) was measured to be less than about 10. The reaction temperature was raised to 90 ℃ and the aqueous layer was separated, followed by vacuum stripping at a temperature of about 110 ℃ or less.

The reaction had 1.949 molar equivalents of alkyl mercaptan to thiadiazole and 2.186 molar equivalents of hydrogen peroxide to thiadiazole, resulting in a total reaction molar ratio of thiadiazole to thiol to peroxide of 1:1.95:2.19. The Total Acid Number (TAN) of the sample was about 10 and the final product had undetectable levels of monoalkylthiadiazole compound, as measured by C NMR, the molar ratio of dialkyl-thiadiazole to monoalkyl-thiadiazole was greater than 99:1.

Example 4

The corrosion inhibitors of comparative example 1 and example 1 were each formulated into finished lubricants at a treat rate of 0.35 wt.%. The finished lubricant also included 0.25 wt.% dimethyl octadecyl phosphonate (DMOP) and the same base additive package in a group 4 base oil having a KV100 of 39.2 cSt.

The finished lubricant was heat aged at about 40 ℃ or about 55 ℃ and evaluated for the presence of Methyl Octadecyl Phosphonate (MOP). The graphs of fig. 1 and 2 show the significant improvement in DMOP stability of the finished lubricants comprising the thiadiazole corrosion inhibitors of the present invention of example 1 as compared to the finished lubricants comprising the comparative thiadiazole corrosion inhibitors of comparative example 1.

The finished lubricant was also evaluated for copper corrosion after 3 hours at 121 ℃ according to ASTM D130, the relative ratio of DMOP to MOP after 8 weeks storage at room temperature (25 ℃) and the FAG FE8 roller bearing weight loss was measured according to DIN 51819-3 at 80 hours, 7.5rpm, 100kN and 80 ℃. The results are provided in table 3 below.

TABLE 3 Table 3

As shown in table 3 above, the finished lubricant comprising the corrosion inhibitor of example 1 had the same copper corrosion grade as the finished lubricant comprising the comparative corrosion inhibitor of comparative example 1, but the lubricant and additive of the invention had a higher molar ratio of phosphonic acid Diester (DMOP) to phosphonic acid Monoester (MOP) and therefore had a significantly improved roller bearing weight loss. The lubricants of example 2 and example 3 and comparative example 2 were expected to be used with similar results.

It should be 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 antioxidant" includes two or more different antioxidants. As used herein, the term "include" and grammatical variants thereof are intended to be non-limiting such that recitation of items in a list is not to the exclusion of other like items that may be substituted or added to the listed items.

For purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing quantities, percentages or proportions used in the specification and claims, and other numerical values, 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 may vary depending upon the desired properties sought to be obtained by the present disclosure. At 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 at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

It is to be understood that each component, compound, substituent, or parameter disclosed herein is to be interpreted as being disclosed for use alone or in combination with one or more of each of the other components, compounds, substituents, or parameters disclosed herein.

It is further understood that each range disclosed herein is to be interpreted as having the same numerical value of each specific value within the range disclosed. Thus, for example, a range of 1 to 4 should be interpreted as an explicit disclosure of the values 1,2, 3, and 4, and any range of such values.

It is further understood that each lower limit of each range disclosed herein is to be interpreted as being combined with each upper limit of each range and each specific value within each range disclosed herein for the same component, compound, substituent, or parameter. Accordingly, this disclosure should be construed as a disclosure of all ranges derived by combining each lower limit of each range with each upper limit of each range or with each specific value within each range, or by combining each upper limit of each range with each specific value within each range. That is, it should be further understood that any range between the endpoints within the broad ranges is also discussed herein. Thus, a range of 1 to 4 also means a range of 1 to 3, 1 to 2, 2 to 4, 2 to 3, etc.

Furthermore, a particular amount/value of a component, compound, substituent, or parameter disclosed in this specification or example should be construed as a disclosure of a lower limit or upper limit of a range, and thus may be combined with any other lower limit or upper limit or particular amount/value of a range for the same component, compound, substituent, or parameter disclosed elsewhere in this disclosure to form that range of component, compound, substituent, or parameter.

Although particular embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are or may not be presently contemplated may be appreciated by the applicant or others skilled in the art. Accordingly, the appended claims as filed and as they may be amended are intended to embrace all such alternatives, modifications, variations, improvements, and substantial equivalents.

Claims (15)

1. A corrosion inhibitor prepared by a process comprising the steps of:

(a) Reacting 1,3, 4-dimercaptothiadiazole or an alkali metal salt thereof with an alkyl mercaptan in the presence of an acid to form a first reaction intermediate;

(b) Reacting the first reaction intermediate with hydrogen peroxide to form the corrosion inhibitor; and

(C) Wherein said 1,3, 4-dimercaptothiadiazole or an alkali metal salt thereof, said alkyl mercaptan, and said hydrogen peroxide are provided in a molar ratio of 1:1.95 to 2.15:greater than 2.0.

2. The corrosion inhibitor according to claim 1, wherein the acid is a strong acid provided in molar excess relative to the 1,3, 4-dimercaptothiadiazole.

3. The corrosion inhibitor according to claim 1, wherein the corrosion inhibitor is about 95% by weight or more of a2, 5-dialkyl-dithiothiadiazole compound and about 5% by weight or less of a mono-alkyl-dithiothiadiazole compound; and/or wherein the corrosion inhibitor has a total acid number of 10 or less; and/or wherein the alkyl portion of the alkyl mercaptan is an aliphatic or aromatic hydrocarbon group; and/or wherein the alkyl portion of the alkyl thiol is a linear or branched C1 to C30 hydrocarbyl group.

4. The corrosion inhibitor of claim 1, wherein the method further comprises heating the corrosion inhibitor to a temperature effective to separate any aqueous layer, and optionally subjecting the heated corrosion inhibitor to vacuum stripping.

5. The corrosion inhibitor of claim 3, wherein the 2, 5-dialkyl-dithiothiadiazole compound has the structure of formula Ia:

And

Wherein the monoalkyl-dithiothiadiazole compound has the structure of formula Ib:

Wherein each R ₁ of formula Ia and/or formula Ib is independently a linear or branched C4 to C20 hydrocarbyl group.

6. The corrosion inhibitor according to claim 1, wherein the dimercaptothiadiazole or an alkali metal salt thereof, the alkyl mercaptan, and the hydrogen peroxide are provided in a molar ratio of 1:1.95-2.15:2.1-2.4.

7. A lubricant, the lubricant comprising:

(a) A substantial amount of base oil; and

(B) A corrosion inhibitor prepared by a process comprising the steps of:

(i) Reacting 1,3, 4-dimercaptothiadiazole or an alkali metal salt thereof with an alkyl mercaptan in the presence of an acid to form a first reaction intermediate;

(ii) Reacting the first reaction intermediate with hydrogen peroxide to form a corrosion inhibitor; and

(Iii) Wherein said 1,3, 4-dimercaptothiadiazole or an alkali metal salt thereof, said alkyl mercaptan, and said hydrogen peroxide are provided in a molar ratio of 1:1.95 to 2.15:greater than 2.0.

8. The lubricant of claim 7, wherein the acid is a strong acid provided in molar excess relative to the 1,3, 4-dimercaptothiadiazole.

9. The lubricant of claim 7, further comprising one or more phosphonate compounds comprising about 90 wt.% or more phosphonate diester and no more than about 10 wt.% phosphonate monoester, based on the total weight percent of phosphonate compounds; and/or wherein the corrosion inhibitor is about 95% by weight or more of a2, 5-dialkyl-dithiothiadiazole compound and about 5% by weight or less of a monoalkyl-dithiothiadiazole compound.

10. The lubricant of claim 7, wherein the 2, 5-dialkyl-dithiothiadiazole compound has the structure of formula Ia:

And

Wherein the monoalkyl-dithiothiadiazole compound has the structure of formula Ib:

Wherein each R ₁ of formula Ia and/or formula Ib is independently a linear or branched C4 to C20 hydrocarbyl group.

11. The lubricant of claim 9, wherein the phosphonate diester has the structure of formula II:

Wherein R ₂ is a C ₁ to C ₅₀ hydrocarbyl group and each R ₃ is independently a C ₁ to C ₂₀ alkyl group; and/or wherein the phosphonic acid diester is dimethyl octadecylphosphonate; and/or wherein the phosphonate monoester has the structure of formula III:

Wherein R ₄ is a C ₁ to C ₅₀ hydrocarbyl group and R ₅ is a C ₁ to C ₂₀ alkyl group; and/or

Wherein the phosphonate monoester is methyl octadecylphosphonate.

12. The lubricant of claim 9, wherein the lubricant exhibits a FAG FE8 roller bearing weight loss of about 12mg or less in accordance with DIN 51819-3 after 80 hours of operation at 80 ℃, 7.5rpm and 100 kN.

13. A corrosion inhibitor additive, the corrosion inhibitor additive comprising:

(a) About 95% by weight or more of a 2, 5-dialkyl-dithiothiadiazole compound;

(b) A monoalkyl-dithiothiadiazole compound, but not more than about 5% by weight of said monoalkyl-dithiothiadiazole compound; and

(C) Wherein the corrosion inhibitor additive has a total acid number of about 10 or less.

14. The corrosion inhibitor according to claim 13, wherein the 2, 5-dialkyl-dithiothiadiazole compound has the structure of formula Ia:

And

Wherein the monoalkyl-dithiothiadiazole compound has the structure of formula Ib:

Wherein each R ₁ of formula Ia and/or formula Ib is independently a linear or branched C4 to C20 hydrocarbyl group.

15. The corrosion inhibitor according to claim 13, wherein the corrosion inhibitor is obtained from dimercaptothiadiazole or an alkali metal salt thereof, an alkyl thiol, and hydrogen peroxide provided in a molar ratio of 1:1.95-2.15:2.1-2.4.