Functional fluids comprising alkyl toluene sulfonates

Abstract

Provided are formulations, methods of making, and methods of using a functional fluid of the present invention to achieve and maintain optimal frictional characteristics in machines housing that fluid, wherein the functional fluid comprises, among others, a friction-modifying amount of an alkyl toluene sulfonate salt or a mixture of alkyl toluene sulfonate salts.

Claims

1. A functional fluid composition comprising an admixture of: (a) a major amount of an oil of lubricating viscosity; and (b) a friction-modifying amount of one or more oil-soluble alkyl toluene sulfonate salts represented by the formula: ##STR00003## wherein R.sub.1 is a metal sulfonate group and R.sub.2 is an alkyl group derived from C.sub.20-C.sub.24 isomerized linear alpha olefins, wherein about 14% to about 31% of each of the isomerized linear olefins are branched, and further wherein the friction-modifying amount of one or more oil-soluble alkyl toluene sulfonate salts in the functional fluid is about 1.5 wt. % to about 2.5 wt. %.

2. The functional fluid composition of claim 1, wherein the one or more alkyl toluene sulfonate salts are chosen from alkali metal salts and alkaline earth metal salts.

3. The functional fluid composition of claim 2, wherein the one or more alkyl toluene sulfonate salts are alkaline earth metal salts.

4. The functional fluid composition of claim 3, wherein the one or more alkyl toluene sulfonate salts are calcium salts.

5. The functional fluid composition of claim 1, wherein the one or more alkyl toluene sulfonate salts are overbased salts.

6. The functional fluid composition of claim 5, wherein the one or more alkyl Ilene sulfonate salts are overbased with carbon dioxide.

7. The functional fluid composition of claim 1, wherein each of the one or more alkyl toluene sulfonate salts has a total base number of about 0 to about 400.

8. The functional fluid composition of claim 5, wherein each of the overbased salts has a total base number of about 60 to about 400.

9. The functional fluid composition of claim 8, wherein each of the overbased salts has a total base number of about 250 to about 380.

10. The functional fluid composition of claim 9, wherein each of the overbased salts has a total base number of about 300 to about 350.

11. The functional fluid composition of claim 1, wherein the one or more alkyl toluene sulfonate salts are derived from alkyl toluene precursors prepared by reacting isomerized linear olefins with toluene.

12. The functional fluid composition of claim 1, wherein about 0.5% to about 50% of each of the isomerized linear olefins are alpha olefins.

13. The functional fluid composition of claim 12, wherein about 1.5% to about 35% of each of the isomerized linear olefins are alpha olefins.

14. The functional fluid composition of claim 1, further comprising one or more additives selected from the group consisting of (1) antioxidants; (2) rust inhibitors; (3) demulsifiers; (4) friction modifying agents other than alkyl toluene sulfonates; (5) viscosity index improvers; (6) multi-functional additives; (7) dispersants; (8) anti-wear/extreme pressure agents; (9) pour point depressants; (10) foam inhibitors; (11) detergents; and (12) seal conditioning agents.

15. The functional fluid composition of claim 1, wherein the friction-modifying capacity of the composition is not substantially diminished in the presence of chloride ions.

16. The functional fluid composition of claim 15, wherein the friction-modifying capacity of the composition is not substantially diminished in the presence of up to about 10 ppm of chloride.

17. The functional fluid composition of claim 16, wherein the friction-Modifying capacity of the composition is not substantially diminished in the presence of up to about 50 ppm of chloride.

18. A method of achieving optimal frictional characteristics and maintaining such characteristics in a machine comprising relatively moving and coupling parts, the method comprising: (a) immersing at least some of the surfaces of the relatively moving and coupling parts in a functional fluid of claim 1; and (b) operating the machine in the presence of the functional fluid.

19. The method according to claim 18, wherein the functional fluid is a tractor fluid, a tractor hydraulic fluid, a transmission fluid, or a hydraulic fluid.

20. The method according to claim 19, wherein the functional fluid is a tractor hydraulic fluid.

21. The method of claim 18, wherein the functional fluid further comprising one or more additives selected from the group consisting of (1) antioxidants; (2) demulsifiers; (3) rust inhibitors; (4) friction modifying agents that are not alkyl toluene sulfonates; (5) pour point depressants; (6) viscosity index improvers; (7) foam inhibitors; (8) multi-functional additives; (9) anti-wear/extreme pressure agents; (10) dispersants; (11) detergents; and (12) seal conditioning agents.

22. A method of making a functional fluid composition comprising blending the following components; (a) an oil of lubricating viscosity; and (b) one or more oil-soluble alkyl toluene sulfonate salts represented by the formula: ##STR00004## wherein R.sub.1 is a metal sulfonate group and R.sub.2 is an alkyl group derived from C.sub.20-C.sub.24 isomerized linear alpha olefins, wherein about 14% to about 31% of each of the isomerized linear olefins are branched, and further wherein the friction-modifying amount of one or more oil-soluble alkyl toluene sulfonate salts in the functional fluid is about 1.5 wt. % to about 2.5 wt. %.

23. The method according to claim 22, further comprising blending one or more additives selected from the group consisting of: antioxidants; rust inhibitors; friction modifying agents that are not alkyl toluene sulfonates; viscosity index improvers; demulsifiers; pour point depressants; anti-wear/extreme pressure agents; multi-functional additives; foam inhibitors; detergents; seal conditioning agents; and dispersants into the functional fluid composition.

24. The functional fluid composition according to claim 1, wherein the functional fluid is a tractor fluid, a tractor hydraulic fluid, a transmission fluid, or a hydraulic fluid.

Description

DETAILED DESCRIPTION

(1) Various preferred features and embodiments are described below by way of non-limiting illustrations.

(2) The present invention relates to a functional fluid composition comprising one or more alkyl toluene sulfonate salts as friction modifying agents. Specifically, the alkyl toluene sulfonate salts of the present invention are salts of oil-soluble alkyl toluene sulfonic acids. The alkyl toluene sulfonate salts of the present invention may be any type of metal salts, including alkaline earth metal salts, alkali metal salts, and the like. An exemplary group of alkyl toluene sulfonate salts of the present invention are calcium salts. Moreover, the salts of the present invention are often overbased salts, although neutral salts are also acceptable. The salts of the present invention may further be overbased with carbon dioxide. The one or more alkyl toluene sulfonate salts of the present invention may be derived from alkyl toluene alkylates that are the alkylation products of toluene and linear olefins. As if is understood by persons skilled in the art and for purpose of the present invention, the term a linear olefin refers to a non-cyclic olefin. Accordingly, the linear olefin used to alkylate the toluene can be branched or unbranched. Furthermore, the linear olefin used to alkylate the toluene can be either a single olefin or a mixture of olefins with varying numbers of carbon atoms. The single olefin and/or the olefins in the mixtures are preferably selected from C.sub.18 to C.sub.30 linear olefins. Regardless of the length of the chains, or whether the alkylating agent is a single olefin or a mixture, however, these olefins are, in some exemplary embodiments, isomerized prior to the alkylation step.

(3) Unless otherwise specified, all percentages are in weight percent.

(4) The Friction Modifying Agents

(5) The friction modifying agents of the present invention comprise alkyl toluene sulfonate salts. These salts can be prepared from alkyl toluene precursors by methods described below.

(6) 1. The Alkyl Toluene Precursors

(7) An alkyl toluene precursor of the present invention may be originally derived front a conventional Friedel-Crafts reaction that alkylates toluene with an olefin. An alkyl toluene precursor of the present invention may comprise an alkyl chain that is about 3 to about 50 carbon atoms long. Another alkyl toluene precursor of the present invention may comprise an alkyl chain that is about 10 to about 40 carbon atoms long. Yet another alkyl toluene precursor of the present invention may comprise an alkyl chain that is about 18 to about 30 carbon atoms long. The toluene ring may be linked to any position on the alkyl chain except for position 1 on the alkyl chain. As persons skilled in the art will appreciate, position 1 on an alkyl chain refers to the carbon position at the end of the chain. On the other hand, the alkyl chain can be linked to the toluene ring at any carbon position, except for the position at which the methyl group of the toluene is attached.

(8) The olefin that is used to alkylate the toluene can be a single olefin or a mixture of various olefins, although the latter is typically the alkylation agent of choice. Regardless whether a single olefin or a mixture is used to alkylate the toluene, the olefins are preferably isomerized. They may be isomerized prior to, during, or after the alkylation step, but are preferably isomerized prior to the alkylation step. At least about 0.5%, more preferably, about 1% to about 50%, and particularly preferably, about 1.5% to about 35% of the olefins in the alkylation agent are alpha olefins. In an exemplary friction modifying agent of the present invention, the alpha olefin content is about 10%. In another exemplary friction modifying agent of the present invention, the alpha olefin content is about 16%. On the other hand, the olefins in the alkylation mixture may be branched or unbranched, but are preferably not entirely unbranched. Preferably, about 5% to about 80% of the olefins are branched, more preferably, about 10% to about 60% of the olefins are branched, and particularly, about 14% to about 31% of the olefins are branched. In an exemplary friction modifying agent of the present invention, about 14% of the olefins in the mixed-olefin alkylation agent are branched. In another exemplary friction modifying agent of the present invention, about 25% of the olefins in the mixed-olefin alkylation agent are branched. In yet another exemplary friction modifying agent of the present invention, about 30% of the olefins in the mixed-olefin alkylation agent are branched.

(9) Methods of isomerizing olefin are known. Persons skilled in the art typically use one of at least two types of acidic catalysts for this purpose. Specifically, the acidic catalysts can be solid or liquid. A number of known solid acidic catalysts may be suitable, but a solid catalyst having at least one metal oxide is preferred. The metal oxide can be one selected from: natural zeolites, synthetic zeolites, synthetic molecular sieves, and clays. Preferably, the solid acidic catalyst comprises the acid forms of an acidic clay, or an acidic molecular sieve, or a zeolite having an average pore size of at least 6.0 angstroms. Useful acidic clays, including, for example, montmorillonite, laponite and saponite, may be derived from naturally-occurring or synthetic materials. Pillared clays may also serve as alleviation catalysts. Other molecular sieves with one-dimentional pore systems, having average pore sizes of less than 5.5 angstroms, may also serve as acidic catalysts. Examples include SM-3, MAPO-11, SAPO-11, SSZ-32, ZSM-23, MAPO-39, SAFO-39, ZSM-22, SSZ-20, ZSM-35, SUZ4, NU-23, NU86, and natural or synthetic ferrierites. These catalysts are described, tor example, in HANDBOOK OF MOLECULAR SIEVES by Rosamarie Szoslak (New York, Van Norsrand Reinhold, 1992), and in U.S. Pat. No. 5,282,858, which are hereby incorporated by reference.

(10) The isomerization process can be carried out, for example, at temperatures ranging from about 50 C. to about 280 C. Because olefins tend to have high boiling points, the process is preferably carried out in the liquid phase, in batch or continuous mode. In the batch mode, a stirred autoclave or glass flask, which may be heated to the desired reaction temperature, is typically used. On the other hand, a continuous process is most efficiently carried out in a fixed-bed process. In a fixed-bed process, space rates, which measure the rates of contact between the reactants and the catalyst beds, can range from about 0.1 WHSV to about 10 or more WHSV (i.e., weight of reactant feed per weight of catalyst per hour). The catalyst is charged into the reactor, which can be heated to the desired reaction temperature. The olefin can also be bested before it is exposed to the catalyst bed. An exotherm of about 10 C. to about 15 C. is often observed along the catalyst bed. The reactor effluent containing partially-branched and isomerized olefin is then collected. In both batch and continuous modes, the resulting partially-branched and isomerized olefin mixture typically contains a certain olefin distribution (alpha-olefin, beta-olefin, internal-olefin, trisubstituted olefin and vinylidene-olefin) and branching content, which can be differentiated from the non-isomerized olefin.

(11) Persons skilled in the art are able to choose isomerization conditions under which particular levels of isomerization may be achieved. Specifically, the level of isomerization is typically characterized by the amount of alpha olefins and the level of branching in a particular olefin sample or mixture. The amount of alpha olefin and the level of branching can in tarn be determined using various conventional methods, including, for example, Fourrier Transformed Infra Red (FTIR) spectroscopy. In a typical FTIR spectroscopy method, the level (or percentage) of alpha olefins can be measured by following the absorbance of a particular sample at 910 cm.sup.1 and comparing it to the 910-cm.sup.1 absorbance of calibration samples with known alpha olefin levels. The level (or percentage) of alpha olefin in the calibration samples can be obtained, for example, from .sup.13C quantitative nuclear magnetic resonance (NMR) spectroscopy according to known protocols.

(12) The percentage of branching can also be measured by FTIR spectroscopy by following the absorbance of a sample at 1378 cm.sup.1. This absorbance corresponds to the extent of deformation vibration of methyl groups. The absorbance of an isomerized olefin sample is then compared to the 1378-cm.sup.1 absorbance of a set of calibration samples with known branching levels. Typically, a particular olefin mix to be tested is first hydrogenated, converting the unbranched portion to n-alkanes and the branched portion to branched alkanes. Gas chromatography is then used to distinguish the unbranched n-alkanes from the branched alkanes, the proportion of which correlates to the percent branching level in that olefin mix.

(13) To achieve the desired levels of isomerization in a particular olefin mixture, a person skilled in the art can also mix olefins of different but known isomerization levels. For example, the skilled person may mix 8 portions of a 45%-branched olefin mix A comprising 15% alpha olefins, with 2 portions of a 25%-branched olefin mix B comprising 5% alpha olefins, to achieve a mixture AB that is 41%-branched and comprising 13% alpha-olefins.

(14) As described above, the olefins used to alkylate toluene in the present invention comprise at least about 0.5%, more preferably, about 1% to about 50%, and particularly preferably, about 1.5% to about 35%, alpha olefins. Suitable olefins in this regard may be about 5% to about 80% branched, more preferably, about 10% to about 60% branched, and particularly preferably, about 14% to about 31% branched.

(15) The alkylation step of the present invention may take place prior to, simultaneously with, or after, the isomerization step. It is however preferred that the isomerization step occurs before the alkylation step, so that the olefins that are used to alkylate toluene comprise isomerized olefins.

(16) Various known alkylation methods can be used to make the alkyl toluene precursors. For example, a typical alkylation reaction, which takes place in the presence of a hydrogen fluoride catalyst, may competently serve this purpose. A high toluene-to-olefin charge/molar ratio, for example, at about 10, is used in a single reactor in order to increase the alkylation rate vs. isomerization and dimerization rate, yielding a reaction product that comprises a high level of monoalkyl toluene. Various other methods can also be used to achieve alkylation, but nearly always, a one-stage reactor is used as the preferred vessel in which the reaction would take place.

(17) The alkylation process typically takes place at a temperature ranging from about 20 C. to about 250 C. Similar to the isomerization process discussed above, the alkylation process is preferably carried out in a liquid phase to accommodate the liquid olefins at these temperatures. The alkylation process may be activated in batch or continuous mode, with the former mode being carried out in a heated and stirred autoclave or glass flask, and with the latter mode carried out in a fixed-bed process.

(18) In the fixed bed process, the catalyst is heated to the desired reaction temperature, for example, at about 100 C. to about 200 C. Pressure is increased by means of a back pressure valve so that, the pressure is above the bubble point pressure of the toluene at the reaction temperature. After pressurizing the system to the desired pressure, the temperature is then increased to the desired reaction temperature. Alternatively, toluene may be introduced into the reactor at reaction temperature. A flow of the olefin is then introduced into the flow of toluene before the mixture comes into contact with the catalyst bed. Regardless of the mode in which the alkylation reaction is carried out, the reactor effluent typically contains alkyltoluene, mixed with excess toluene. The excess toluene can be removed by distillation, stripping evaporation under vacuum, or other means known to those skilled in the art.

(19) 2. The Alkyl Toluene Sulfonate Salts

(20) The alkyl toluene sulfonate salts of the present invention are represented by the general formula:

(21) ##STR00002##
wherein R.sub.1 is a metal sulfonate group, and R.sub.2 is an alkyl group. Moreover, the alkyl toluene sulfonate salts of the present invention are oil-soluble.

(22) These salts are derived from alkyl toluene sulfonic acids, which can be prepared by sulfonating the alkyl toluene precursors. Specifically, the alkyl toluene precursors described above may be sulfonated in conventional ways, such as using a SO.sub.3/Air Thin Film Sulfonation method. Applying that method, the alkyl toluene precursor is mixed with a SO.sub.3/Air falling film made by CHEMITHON or BALLESTRA.

(23) The sulfonate salts of the present invention can be prepared by methods known to those skilled in the art. For example, they may be obtained by reacting alkyl toluene sulfonic acids with sources of suitable metals. An exemplary method comprises combining a reactive base of a metal, such as a hydroxide, with an alkyl toluene sulfonic acid. This is conventionally earned out in the presence of a hydroxylic promoter such as water; alcohols such as 2-ethyl hexanol, methanol, or ethylene glycol; and typically in an inert solvent, in which the resulting sulfonate salts may be dissolved. The reaction mixtures are typically heated. After the reactive bases of the metals are converted into the metal sulfonates, the reaction, promoters and solvents can be removed by distillation and other conventional methods.

(24) The metals that form the alkyl toluene sulfonate salts of the present invention may be any known metals feat are capable of forming salts with alkyl toluene sulfonic acids. In a particular embodiment of the present invention, the metal is an alkali metal or an alkaline earth metal. The term alkaline earth metal refers to calcium, barium, magnesium and strontium. The term alkali metal refers to lithium, sodium, potassium, rubidium, cesium and francium. In a further embodiment of the present invention, the metal is an alkaline earth metal. In yet another specific embodiment of the present invention, the metal is calcium.

(25) The alkyl toluene sulfonate salts of the present invention may be either neutral or overbased salts. Overbased materials are characterized by a metal content in excess of that which would be present according to the stoichiometry of the metal cation in the sulfonate said to be overbased. The term base number or BN refers to the amount of base equivalent to milligrams of KOH in one gram of sample. Thus, a higher BN reflects more alkaline products and thus a greater alkalinity reserve. The BN of samples can be determined by a variety of methods, including, for example, ASTM test No. D2896 and other equivalent procedures. The term total base number or TBN refers to the amount of base equivalent to milligrams of KOH in one gram of functional fluid. These terms are often used interchangeably with base number or BN, respectively. The term low overbased refers to a BN or TBN of about 2 to about 60. The term high overbased refers to a BN or TBN of about 60 or more.

(26) The alkyl toluene sulfonate salts of the present invention may be either neutral or overbased salts. Accordingly, they may have a TBN of about 0 to about 400. The alkyl toluene sulfonate salts of the present invention are preferably overbased to provide a TBN of about 2 to about 400, and preferably highly overbased to have a TBN of between about 60 to about 400, more preferably about 220 to about 380, and particularly preferably about 280 to about 350. An exemplary alkyl toluene sulfonate, salt of the present invention is highly overbased with a TBN of about 320.

(27) Methods and reaction conditions for overbasing are known in the art, for example, as generally disclosed in U.S. Pat. No. 3,496,105, which is incorporated herein by reference to the extent it does not conflict with the disclosures and the claims herein. For the present invention, the overbasing may be carried out with carbon dioxide. It is believed that the carbon-dioxide treatment may lead to the formation of a colloidal dispersion of metal base. Typically, the overbased salts of the present invention are formed in the presence of methanol and xylene, and in the absence of chlorine.

(28) The alkyl toluene sulfonate salts of the present invention are useful as additives in functional fluids in amounts sufficient to provide the desired frictional properties to the fluids, and to improve brake and clutch capacities in machines housing those fluids. Typically, at least about 0.15 wt. % of a single alkyl toluene sulfonate salt or a mixture of such salts is used in a finished functional fluid of the present invention. In various embodiments of the present invention, the amount of sulfonates in the finished functional fluid may range from, about 0.15 wt. % to about 4.0 wt. %, or from about 0.5 wt. % to about 3.5 wt. %, or from about 1.5 wt. % to about 2.5 wt. %. An exemplary finished functional fluid of the present invention comprises about 1.8 wt. % of a certain alkyl toluene sulfonate salt mixture.

(29) The Functional Fluids

(30) The functional fluid of the present invention comprises one or more base oils, which are present in major amounts (i.e., an amount greater than about 50 wt. %). Generally, the base oil or the mixture of base oils is present in an amount greater than about 60 wt. %, or greater than about 70 wt. %, or greater than about 80 wt. %, based on the total mass of the functional fluid. An exemplary functional fluid of the present invention comprises about 88 wt. % of a mixture of base oils.

(31) The base oils may be derived from mineral oils, synthetic oils or vegetable oils. A base oil having a viscosity of at least about 2.5 cSt at about 40 C. and a pour point at or below about 20 C. preferably at or below about 0 C., is desirable. The base oils may be derived from synthetic or natural sources. Suitable base oils may be selected from any one or combination of Group I through Group V base stocks as defined in American Petroleum Institute Publication 1509, which is herein incorporated by reference. Suitable base oils may also include various newly developed base stocks, for example, those that are informally referred to as Group I/+, Group II/+, or Group III/+, as well, as other base stocks that are currently used by skilled persons in the art. General descriptions of these newly developed base stocks can be found in various places, for example, at Chevron's products/base oils website (www.chevron.com/products/prodserv/BaseOils/gf4_faq.shtml).

(32) Natural base oils may include, for example, mineral oils and vegetable oils. Mineral oils suitable for use as the base oil of this invention include, for example, paraffinic, naphthenic and other oils that are ordinarily used in lubricating oil compositions. Suitable vegetable oils may include, for example, canola oil or soybean oil.

(33) Synthetic oils of proper viscosity include, for example, hydrocarbon synthetic oils, synthetic esters, and mixtures thereof. Hydrocarbon synthetic oils may include, for example, oils prepared from the polymerization of ethylene, higher olefins, examples of which include polyalphaolefin or PAO, or from hydrocarbon synthesis procedures using carbon monoxide and hydrogen gases such as in a Fisher-Tropsch process. Useful synthetic hydrocarbon oils include liquid polymers of alpha olefins having the proper viscosity. Especially useful are the hydrogenated liquid oligomers of C.sub.6 to C.sub.12 alpha olefins such as 1-decene trimer. Likewise, alkyl benzenes of proper viscosity, such as didodecyl benzene, can be used. Useful synthetic esters include esters of monocarboxylic acids and polycarboxylic acids, as well as mono-hydroxy alkanols and polyols. Typical examples are didodecyl adipate, pentacrythritol tetracaproate, di-2-ethylhexyl adipate, dilaurylsebacate, and the like. Complex esters prepared from mixtures of mono- and dicarboxylic acids and mono- and dihydroxy alkanols can also be used. Blends of mineral oils with synthetic oils are likewise potentially useful.

(34) An exemplary functional fluid of the present invention employs a mixture of two Group 1 base oils, EXXON MOBIL AP/E CORE 150N and EXXON MOBIL AP/E CORE 600N.

(35) A functional fluid of the present invention contains a friction-modifying amount of one or more alkyl toluene sulfonate salts as described herein. Typically, at least about 0.15 wt. % of one or more alkyl toluene sulfonate salts are included in a functional fluid of the present invention. Preferably, the concentration of alkyl toluene sulfonate salts in the functional fluid ranges from about 0.15 wt. % to about 4.0 wt. %, more preferably from about 0.5 wt. % to about 3.5 wt. %, and particularly preferably from about 1.5 wt. % to about 2.5 wt. %. An exemplary functional fluid of the present invention comprises about 1.8 wt. % of an alkyl toluene sulfonate salt mixture.

(36) Besides the alkyl toluene sulfonate salts of the present invention, the functional fluid may comprise other additives as described below. These additional components can be blended in any order and can be blended as combinations of components. The fallowing additive components are provided as examples of components that may be favorably employed, without limiting the scope of the present invention.

(37) Various dispersants may be added to the functional fluids of the present invention. Dispersants, and typically those of the ashless (metal-free) kinds are typically used in lubricants and functional fluids to maintain in suspension insoluble materials resulting from oxidation dining use, thus preventing sludge flocculation and precipitation, or deposition on metal parts. An ashless dispersant generally comprises an oil-soluble polymeric hydrocarbon backbone having functional groups that are capable of associating with particles to be dispersed. Many types of ashless dispersants are known in the art, including amines, alcohols, amides, or ester polar moieties attached to the polymer backbones via bridging groups. The ashless dispersants of the present invention may be chosen from, for example, oil-soluble salts, esters, amino-esters, amides, imides, and oxazolines of long-chain hydrocarbon-substituted mono and dicarboxylic acids or their anhydrides, thiocarboxylate derivatives of long-chain hydrocarbons, long-chain aliphatic hydrocarbons having a polyamine attached directly thereto; and Mannich condensation products formed by condensing a long-chain substituted phenol with formaldehyde and polyalkylene polyamine. Examples of suitable ashless dispersants may include carboxylic dispersants, which are reaction products of carboxylic acylating agents (acids, anhydrides, esters, etc.) comprising at least 34 and preferably at least 54 carbon atoms with nitrogen-containing compounds (such as amines), organic hydroxyl compounds (such as aliphatic compounds including monohydric and polyhydric alcohols, or aromatic compounds including phenols and nephthols), and/or basic inorganic materials. Succinimide dispersants are a species of carboxylic dispersants, which may be produced by reacting hydrocarbyl-substituted succinic acylating agent with organic hydroxyl compounds, or with amines comprising at least one hydrogen atom attached to a nitrogen atom, or with a mixture of the hydroxyl compounds and amines. Examples of suitable ashless dispersants also include, for example, amine dispersants, which are reaction products of relatively high molecular weight aliphatic halides and amines, preferably polyalkylene polyamines. Examples thereof have been described, for example, in U.S. Pat. Nos. 3,275,554, 3,438,757, 3,454,555, 3,565,804, and the like. Examples of suitable dispersants also include, for example, Mannich dispersants, which are the reaction products of alkyl phenols in which the alkyl group contains at least 30 carbon atoms with aldehydes (especially formaldehyde) and amines (especially polyalkylene polyamines). These dispersants have been described, for example, in U.S. Pat. Nos. 3,036,003, 3,586,629, 3,591,598, 3,980,569, and the like. Suitable ashless dispersants may even include post-treated dispersants, which can be obtained by reacting carboxylic, amine or Mannich dispersants with reagents such as dimercaptothiazoles, urea, thiourea, carbon disulfide, aldehydes, ketones, carboxylic acids, hydrocarbon-substituted succinic anhydrides, nitrile epoxides, boron compounds and the like. Post-treated dispersants have been described, for example, in U.S. Pat. Nos. 3,329,658, 3,449,250, 3,666,730, and the like. Suitable ashless dispersants may also include polymeric dispersants, such as those described in, for example, U.S. Pat. Nos. 3,329,658, 3,449,250, 3,666,730, and the like. The disclosures of the herein patents, to the extent they do not conflict with the disclosures and claims herein, are incorporated in their entirely by reference.

(38) Metal-containing detergents may be added, to the functional fluids of the present invention. Such detergents may include, for example, sulfurized or unsulfurized alkyl or alkenyl phenates, sulfonates derived from synthetic or natural feedstocks, carboxylates, salicylates, phenalates, sulfurized or unsulfurized metal salts of multi-hydroxy alkyl or alkenyl aromatic compounds, alkyl or alkenyl hydroxy aromatic sulfonates, sulfurized or unsulfurized alkyl or alkenyl naphthenates, metal salts of alkanoic acids, metal salts of an alkyl or alkenyl multiacid, and chemical or physical mixtures thereof. Such metal-containing detergents may be overbased or neutral. Overbased metal-containing detergents may be high-overbased or low-overbased.

(39) Antioxidants are optionally added to the functional fluids to reduce the tendency of mineral oils to deteriorate in service. Such deterioration may otherwise lead to deposits of sludge and varnish-like debris on metal surfaces. The oxidation deterioration may also lead to an unacceptable increase in viscosity in the fluids, impairing the performance of the machines that house the functional fluid, and/or damaging the relatively moving and coupling parts. Many antioxidants are known in the art, including, for example, phenol-type (phenolic) oxidation inhibitors, such as 4,4-methylene-bis(2,6-di-tert-butylphenol), 4,4-bis(2,6-di-tert-butylphenol), 4,4-bis(2-methyl-6-tert-butylphenol), 2,2-methylene-bis(4-methyl-6-tert-butylphenol), 4,4-butyldene-bis(3-methyl-6-tert-butyl phenol), 4,4-isopropylidene-bis(2,6-di-tert-butylphenol), 2,2-methylene-bis(4-methyl-6-nonylphenol), 2,2-isobutylidene-bis(4,6-dimethylphenol), 2,2-methylene-bis(4-methyl-6-cyclohexylphenol), 2,6-di-tert-butyl-4-ethylphenol, 2,4-dimethyl-6-tert-butyl-phenol, 4,4-thiobis(2-methyl-6-tert-butylphenol), 2,2-thiobis(4-methyl-6-tert-butylphenol), and bis(3,5-di-tert-butyl-4-hydroxybenzyl). Antioxidants may also be of the diphenylamine-type, which include, for example, alkylated diphenylamine, phenyl--naphthylamine, and alkylated--naphthylamine. Other types of oxidation inhibitors may include, for example, metal dithiocarbamate (e.g., zinc dithiocarbamate), methylene bis-(dibutyldithiocarbamate), and the like.

(40) One or more anti-wear/extreme pressure agents may be included in the functional fluid compositions of the present invention, especially when the fluids are blended for use in heavy-duty machines such as farm tractors. As their name implies, these agents reduce wear of moving metallic parts. Examples of such agents include phosphates, carbamates, esters, sulfur-containing compounds, molybdenum complexes, zinc dialkyldithiophosphate (primary alkyl-, secondary alkyl-, and aryl-types), sulfurized oils, sulfurized isobutylene, sulfurized polybutene, methyl trichlorostearate, chlorinated naphthalene, fluoro-alkylpolysiloxane, and lead naphthenate.

(41) One or more rust inhibitors may also be added to the functional fluid. These agents typically fall into two broad categories: nonionic polyoxyethylene surface active agents, and other compounds. Nonionic polyoxyethylene surface active agents include, for example, polyoxyethylene lauryl ether, polyoxyethylene higher alcohol ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene octyl stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene sorbitol, monostearate, and polyethylene glycol monooleate. Other rust-inhibiting compounds include, for example, stearic acid and other fatty acids, dicarboxylic acids, metal soaps, fatty acid amine salts, metal salts of heavy sulfonic acid, partial carboxylic acid ester of polyhydric alcohol, and phosphoric ester.

(42) It is not uncommon to include demulsifiers in functional fluids, especially when such fluids are used in environments where water contamination is prevalent or inevitable. Typical demulsifiers include, for example, the addition product of alkylphenol and ethylene oxide, polyoxyethylene alkyl ether, and polyoxyethylene sorbitan ester.

(43) In addition to the friction-modifying amount of alkyl toluene sulfonate salts, the functional fluids of the present invention may optionally comprises one or more other friction modifiers. These other friction modifiers may be selected from, for example, fatty alcohols, 1,2-diols, borated 1,2-diols, fatty acids, amines, fatty acid amides, borated esters, and other esters.

(44) As it is known in the art, many additives are multifunctional. For example, a particular compound may be included in the lubricating fluid to provide dispersancy in addition to antiwear properties. Suitable multifunctional additives include, for example, sulfurized oxymolybdenum dithiocarbamate, sulfurized oxymolybdenum organo phosphorodithioate, oxymolybdenum, monoglyceride, oxymolybdenum diethylate amide, amine-molybdenum complex compound, and sulfur-containing molybdenum complex compound.

(45) A functional fluid of the present invention may optionally include one or more viscosity index improvers. They include, for example, polymethacrylate-type polymers, ethylene-propylene copolymers, styrene-isoprene copolymers, hydrogenated styrene-isoprene copolymers, polyisobutylene, and dispersant-type viscosity index improvers.

(46) For certain applications, a functional, fluid of the present invention may also include one or more pour point depressants, including, for example, polymethyl methacrylate.

(47) Moreover, a functional fluid of the present invention may comprise one or more foam inhibitors. Suitable foam inhibitors include, for example, alkyl methacrylate polymers, dimethyl silicone polymers, and like molecules.

(48) The functional fluid compositions of the present invention are formulated by known methods. The formulation is typically carried out at the additive manufacturing plant or blending facility, but the compositions can also be formulated by hand.

(49) Often all the additives, except for the viscosity index improvers and pour point depressants, are blended into a concentrate or additive package that is subsequently blended into base stock to make finished fluids. Use of such concentrates is conventional and well known. The concentrates are formulated to contain the additives in proper amounts so as to provide the desired concentration in the final formulation when the concentrate is combined with a predetermined amount of base oils.

(50) Chloride Compatibility

(51) There may be occasionally a need to use the friction modifying agents and functional fluids of the present invention in the presence of certain amounts of chloride ions. For example, the process to manufacture alkyl toluene sulfonate salts may itself introduce chloride ions into the environment wherein a friction modifying agent of the present invention is used because one or more chloride-containing compounds may be added to modify viscosity during that process. Having a class of friction modifying agents that can be used in the presence of chloride ions is therefore desirable as such friction modifying agents can be used without necessarily removing the chloride ions.

(52) The friction-modifying capacities of the alkyl toluene sulfonate salts and functional fluids of the present invention are not substantially diminished in the presence of chloride ions. Accordingly, other additives and the base oils in these functional fluids are likewise compatible with the presence of chloride. Typically, the friction-modifying capacities of the alkyl toluene sulfonate salts and functional fluids of the present invention are not substantially diminished in the presence of up to about 10 ppm, preferably up to about 20 ppm, and particularly preferably up to about 50 ppm of chloride ions. In an exemplary embodiment, the presence of about 50 ppm of chloride does not substantially diminish the friction-modifying capacity of a certain functional fluid prepared according to the specifications of the present invention. For purposes of the present invention, the term not substantially diminish refers to a reduction of not more than 5%, 10%, 20%, or 30% of friction-modifying capacity. Accordingly, chloride ions are said to not substantially diminish the friction-modifying capacity of a certain alkyl toluene sulfonate salt/mixture or a functional fluid when its friction-modifying capacity in the presence of chloride is at least about 70%, about 80%, about 90%, or about 95%, of its friction-modifying capacity in the absence of chloride.

(53) This invention will be further understood by reference to the following examples, which are not to be considered as limitative of its scope.

EXAMPLES

(54) The following examples are provided to illustrate the present invention without limiting it. While the present invention has been described with reference to specific embodiments, this application is intended to encompass those various changes and substitutions that may be made by those skilled in the art without departing from the spirit and scope of the appended claims.

Example 1

Improving Static Breakaway Friction Values

(55) Various finished functional fluid samples were prepared. Their friction-modifying capacities were measured in a static breakaway friction bench test designed to simulate the conditions under which a set of wet brakes or wet clutches may operate. The device in which the tests were carried out comprised a brake disc, which was lubricated in an open oil sump with Functional Fluid Samples 1 to 10 and Comparative Functional Fluid A, which are listed below in Table 3. The device further comprised friction pads, which were in contact with the brake disc, and a shaft that rotated the brake disc. During each test, a certain level of pressure was applied on the friction pads, and an electric motor drove the shaft to rotate while the brake disc, was held in its original position. At a particular pressure level, a reading of maximum resisting torque reached within 0.25 seconds after the shaft starts to rotate was recorded. Ten of these 0.25-second cycles were carried out at each pressure level. An average was taken from the 10 maximum torque readings, yielding a 10-round average maximum torque, which was then divided by the level of pressure to arrive at a static breakaway friction value.

(56) The Negative Control Sample comprised an alkyl benzene sulfonate instead of an alkyl toluene sulfonate mixture of the present invention, in an amount that provided the same concentration of Ca.sup.2+ as in the Functional Fluid Samples and Comparative Fluid Sample A. The increase in static breakaway friction values were determined by subtracting the static breakaway friction values of the Negative Control Sample [Y] from the values of the Functional Fluid Samples and Comparative Fluid Sample A [X]. Functional Fluid Samples 1 to 10 and Comparative fluid Sample A exhibited significant increase in static breakaway friction values.

(57) Olefins of various branching/isomerization levels (Olefins I to VIII in Table 1) were mixed to prepare the alkylation agents (the olefin mixes in Table 2). These olefin mixes were then used to prepare alkyl toluenes (ATs I to X in Table 2). To prepare the Comparative Package A, non-isomerized Olefin(comp) (Table 1) was used to alkylate toluene, yielding AT(comp) (Table 2). To prepare the Negative Control package, the same, non-isomerized Olefin(comp) (Table 1), was used to alkylate benzene, yielding AB() (Table 2). These alkylated precursors were sulfonated by conventional methods such as the SO.sub.3/Air Thin Film Sulfonation method described herein. The sulfonation products were then introduced to additive packages at concentrations that would provide about the same amount of Ca.sup.2+ to the fluids. Other components of the additive packages are also listed in Table 2.

(58) All sulfonation products, including the ones comprising the AB() and the AT(comp), were highly overbased to give a TBN of about 320.

(59) TABLE-US-00001 TABLE 1 The Olefins Branching Alpha-Olefin Olefin # Carbon Numbers Levels Concentrations Olefin I 20-24 20.4% 12.1% Olefin II 20-26 54.8% 1.6% Olefin III 20-24 25.0% 1.1% Olefin IV 20-26 23.4% 31.9% Olefin V 20-24 21.2% 5.6% Olefin VI 20-24 17.5% 12.0% Olefin VII 20-26 20.7% 11.7% Olefin VIII 20-26 0 Non-isomerized Olefin(comp) 20-24 0 Non-isomerized

(60) TABLE-US-00002 TABLE 2 The Alkylation Agents & Friction Modifying Agents Packages Additive Sulfonate Package # (wt. %) AT # Olefin mixes Branch (%) Optional Components 1 1.8 I 80% Olefin I 27.3 Examples** of optional 20% Olefin II components that can be 2 1.8 II 80% Olefin I 21.0 favorably employed in the 20% Olefin IV packages, selected from one or 3 1.8 III 80% Olefin III 31.0 more of: 20% Olefin II a) antioxidants; 4 1.8 IV 80% Olefin III 24.7 b) anti-wear/extreme pressure 20% Olefin IV agents; 5 1.8 V 100% Olefin V 21.2 c) detergents 6 1.8 VI 80% Olefin V 17.0 d) rust inhibitors; 20% Olefin VIII e) non-alkyl toluene sulfonate 7 1.8 VII 100% Olefin VI 17.5 friction modifiers; 8 1.8 VIII 90% Olefin VI 15.8 f) multi-functional additives; 10% Olefin VIII g) foam inhibitors; 9 1.8 IX 80% Olefin VI 14.0 h) demulsifiers; 20% Olefin VIII i) dispersants; 10 1.8 X 100% Olefin VII 20.7 j) seal conditioning agents Comp. 1.8 AT Olefin(comp) 0 Pack. A (comp) Negative 1.9* AB() Olefin(comp) 0 Control Package *The alkyl benzene sulfonate in the Negative Control package (i.e., 1.9 wt. %) provided an equivalent amount of Ca.sup.2+ to the package as did the alkyl toluene sulfonates in the other packages (i.e., 1.8 wt. %). **The optional components listed in this column are merely examples of the type of components that can be employed for purpose of the present invention. They are listed herein to illustrate the claimed invention without limiting it.

(61) The Additive Packages of Table 2 were further blended with a certain mixture of base oils, one or more viscosity improvers, and one or more pour point depressants. The finished functional fluids and their components are listed in Table 3.

(62) TABLE-US-00003 TABLE 3 Components of the Finished Functional Fluids Functional Additive Package Fluid # (6.85 wt. %) Other Components 1-10 1-10 Viscosity Index Improver 4.75 wt. % Comp. Comp. Pour Point Depressant 0.20 wt. % Functional Pack. A EXXON MOBIL 54.70 wt. % Fluid A AP/E Core 150N EXXON MOBIL 33.50 wt. % AP/E Core 600N

(63) Static breakaway friction values were determined. Each sample or comparative sample (value [X]) was measured in parallel with a negative control sample (value [Y]) to account for experimental variability. The results for Functional Fluid samples 1 to 10 and Comparative Functional Fluid A are listed in Table 4.

(64) TABLE-US-00004 TABLE 4 Test Results Static Breakaway Increase in Static Static Breakaway Friction of Negative Breakaway Friction Sam- Friction Values Control Values ple # (mm.sup.3) = [X] (mm.sup.3) = [Y] (mm.sup.3) = [X] [Y] 1 17463 17010 453 2 17617 17010 607 3 17653 17010 643 4 17340 17010 330 5 17869 17110 759 6 17364 16924 440 7 17951 16881 1070 8 16555 15965 590 9 16923 15965 958 10 16638 15965 673 Comp. 17766 17441 325 Functional Fluid A

Example 2

Chloride Compatibility

(65) Chloride compatibility of a friction modifying agent, i.e., an alkyl toluene sulfonate salt made from alkyl toluene precursor (AT) XI, and a functional fluid, i.e., Functional Fluid Sample 11, was determined using Comparative Functional Fluid B. Components of these samples are listed in Table 5. Alkyl toluene precursor (AT) XI had a branching level of about 20.7% and an alpha olefin content of about 11.7%.

(66) A static breakaway value of a Negative Control fluid comprising a Ca.sup.2+-equivalent amount of alkyl benzene sulfonate instead of alkyl toluene sulfonate was obtained in parallel with Functional Fluid Sample 11 and Comparative Functional Fluid B. This value was then subtracted from the static breakaway values of the samples to yield the static breakaway friction increases results in Table 5.

(67) Functional Fluid Sample 11 and Comparative Functional Fluid B both showed higher breakaway friction values than the Negative Control fluid, suggesting that these fluids both had improved frictional properties. The presence of chloride in Fluid Sample 11 did not substantially diminish the friction-modifying capacity of the alkyl toluene sulfonate salts in that fluid.

(68) TABLE-US-00005 TABLE 5 Functional Fluid Sample 11 Comparative Functional Fluid B 1.8 wt. % AT sulfonate XI (20.7% branched) 1.8 wt. % AT sulfonate XI (20.7% branched) Package may also optionally comprise one or Package comprises the same optional components more of the following components: * as in Functional Fluid Sample 11 and at the same a) antioxidants; concentrations, which may be one or more b) anti-wear/extreme pressure agents; selected from: * c) rust inhibitors; a) antioxidants; d) detergents; b) anti-wear/extreme pressure agents; e) non-alkyl toluene sulfonate friction modifiers; c) rust inhibitors; f) foam inhibitors d) detergents; g) dispersants; e) non-alkyl toluene sulfonate friction modifiers; h) demulsifiers; f) foam inhibitors i) multi-functional additives; and g) dispersants; j) seal conditioning agents. h) demulsifiers; 50 ppm Cl.sup. i) multi-functional additives; and Other components in the functional fluid: j) seal conditioning agents. a) 0.20 wt. % pour point depressant 0 ppm Cl.sup. b) 4.75 wt. % viscosity index improver Other components in the functional fluid: c) ~88 wt. % EXXON MOBIL AP/E CORE a) 0.20 wt. % pour point depressant Base Oils (mixed) b) 4.75 wt. % viscosity index improver Static Breakaway Friction Increase = 1346 mm.sup.3 c) ~88 wt. % EXXON MOBIL AP/E CORE Base Oils (mixed) Static Breakaway Friction Increase = 673 mm.sup.3 * The following is a non-limiting list of optional components that may be favorably employed.