WO2014033634A2

WO2014033634A2 - Lubricant additive and lubricant oil compositions and process of preparing thereof

Info

Publication number: WO2014033634A2
Application number: PCT/IB2013/058045
Authority: WO
Inventors: Samik Kumar HAIT; Om Prakash; Ramakumar Sankara Sri VENKATA; Biswajit Basu
Original assignee: Indian Oil Corporation Limited
Priority date: 2012-08-29
Filing date: 2013-08-28
Publication date: 2014-03-06
Also published as: WO2014033634A3

Abstract

The present invention discloses an ashless lubricant additive comprising an oil insoluble organic compound. Said lubricant additive can be added in high loadings in a lubricant oil to achieve desired TBN. The invention also discloses process for preparing the lubricant additive composition of the present invention.

Description

LUBRICANT ADDITIVE AND LUBRICANT OIL COMPOSITIONS AND PROCESS OF PREPARING THEREOF

FIELD OF THE INVENTION

The present invention relates to a lubricant additive and lubricant oil composition and the process of preparation for the same. More particularly, it relates to an ashless lubricant additive composition which imparts a significant amount of basicity to a lubricant composition.

BACKGROUND OF THE INVENTION

During the combustion of hydrocarbon fuels, acidic byproducts, and sludge are formed. These acidic materials and sludge are carried down into the lubricant system present in internal combustion engines. The acidic materials and sludge, if left untreated, would cause severe deterioration of the lubricating properties of the lubricant. Additives are commonly added to lubricant to impart properties needed for lubrication of modern engines. Modern lubricants must be able to disperse sludge and neutralize acidic materials produced by combustion.

Materials disclosed in the prior art which impart acid neutralizing properties are commonly formed by over basing a hydrocarbon sulfonic acid with metal bases such as magnesium oxide, calcium carbonate, and calcium oxide. As the lubricating oil which contains the metal sulfonates is consumed, the metal forms ashy deposits and residue.

Environmental concerns have led to continued efforts to reduce the CO, hydrocarbon and nitrogen oxide (NO_x) emissions of compression ignited (diesel-fueled) and spark ignited (gasoline-fueled) light duty internal combustion engines. Further, there have been continued efforts to reduce the particulate emissions of compression ignited internal combustion engines. To meet the upcoming emission standards for heavy duty diesel vehicles, original equipment manufacturers (OEMs) will rely on the use of additional exhaust gas after- treatment devices. Such exhaust gas after-treatment devices may include catalytic converters, which can contain one or more oxidation catalysts, NO_x storage catalysts, and/or N¾ reduction catalysts; and/or a particulate trap. Oxidation catalysts can become poisoned and rendered less effective by exposure to certain elements/compounds present in engine exhaust gasses, particularly by exposure to phosphorus and phosphorus compounds introduced into the exhaust gas by the degradation of phosphorus-containing lubricating oil additives. Reduction catalysts are sensitive to sulfur and sulfur compounds in the engine exhaust gas introduced by the degradation of both the base oil used to blend the lubricant, and sulfur- containing lubricating oil additives. Particulate traps can become blocked by metallic ash, which is a product of degraded metal-containing lubricating oil additives. This ashy residue causes severe problems including poisoning of catalytic converters, interfere with normal combustion of fuel, and reduce the effectiveness of other additives in the lubricating oil.

To ensure a long service life, lubricating oil additives that exert a minimum negative impact on such after-treatment devices must be identified, and OEM specifications for "new service fill" and "first fill" heavy duty diesel (HDD) lubricants require maximum sulfur levels of 0.4 mass %; maximum phosphorus levels of 0.12 mass %, and sulfated ash contents below 1.1 mass %, which lubricants are referred to as "mid- SAPS" lubricants (where "SAPS" is an acronym for "Sulfated Ash, Phosphorus, Sulfur"). In the future, OEMs may further restrict these maximum levels to 0.08 mass % phosphorus, 0.2 mass % sulfur and 0.8 mass % sulfated ash, with such lubricants being referred to as "low-SAPS" lubricating oil compositions.

Projected & forecasted global engine emissions standards for the period 2010 and beyond requires significant changes in the formulations of crankcase oils, including crankcase oils for heavy duty diesel engines with emphasis on providing oils with significant reduction in sulfur, phosphorus, and sulfated ash. However, such lower levels of elements have impact on performance of lubricating engine oils. Reduced ash levels necessitate a reduction in the amount of detergent containing metals like calcium, magnesium etc., which have been used to provide base to neutralize acidic fuel and lubricant degradation products. This neutralizing function of dispersant detergent combination is directly linked for use with extended oil drain intervals, where reduced detergent levels may jeopardize oil life. The challenge is to deliver basicity without adding ash or harming seal compatibility, which is often a problem when basic nitrogen compounds are added.

Historically, TBN (Total Base Number) has been provided by overbased detergents that introduce sulfated ash into the composition. It would be advantageous to provide a lubricating oil composition with a high level of TBN using a TBN boosting component that does not contribute sulfated ash. As highly basic components are known to induce corrosion and, in some cases reduce the compatibility between lubricating oil compositions and the fluoroelastomeric seal materials used in engines, it would be preferable to provide such a component that does not induce corrosion and, preferably, does not adversely affect seal compatibility. Due to demands for improved fuel economy, less viscous lubricants, such as 0 W and 5 W 20 and 30 grade lubricants have become more prevalent. To allow for easier formulation of such lubricants, the amount of polymer introduced by additives is preferably minimized. Therefore, it would be further preferable to provide a non-polymeric ashless TBN source.

US Pat. No. 2,823,182 discloses a normally liquid oleaginous compound, preferably a hydrocarbon oil, and from about 0.5% to about 70%, and preferably from about 1% to about 20%, of a guanidine sulfonate. The guanidine sulfonate can be the guanidine or alkyl guanidine salt of hydrocarbon oil sulfonic acids obtained in the treatment of hydrocarbon oils with strong sulfuric acid or of alkanesulfonic acids or of arylsulfonic acids, alkyl aryl sulfonic acids, and mixtures thereof. The sulfonic acids can be preferentially oil-soluble sulfonic acids or preferentially water-soluble sulfonic acids. However, when the guanidine salts of preferentially water-soluble sulfonic acids, i.e., low molecular weight, are employed, they are used in combination with salts of preferentially oil-soluble sulfonic acids.

US Pat. No. 2,660,562 discloses improved ashless lubricant compositions comprising mineral oils incorporated with a guanidine salt of an organic sulfonic acid selected from the group consisting of synthetic guanidine alkyl aryl sulfonates and guanidine petroleum sulfonates, and containing from 0.1 to 60 weight percent of the guanidine salt.

US Pat. No. 2,702,819 discloses synthetic guanidine alkyl hydro carbonaryl sulfonates containing a total number of at least 10 carbon atoms in the alkyl groups. This patent also discloses that many guanidine sulfonates are very insoluble compounds, unsuitable as lubricant additives.

US Pat. Nos. 5,525,247; 5,672,570; and 6,569,818 are directed to "low ash" lubricating oil compositions in which sulfated ash content is reduced by replacing overbased detergents with neutral detergents (phenates & salicylates). These patents describe such lubricants as providing sufficient detergency, but make no claim that such lubricants will provide enough TBN for use, as an example, in heavy duty diesel engines. US Patent Application 2007/0203031 describes the use of a high TBN nitrogen-containing dispersants as ashless TBN sources, but not enough to take care of engine requirement.

US Patent 7,749,948 describes at least one non-metal-containing polymeric additive, comprising a nitrogen-containing dispersant having a total base number of at least about 90 are useful for lubricating an internal combustion engine. The lubricants have less than 1.0% sulfated ash. The lubricants exhibit a high TBN without deterioration of elastomeric seals.

US Pat. Nos. 4,100,082; 4,200,545; 4,320,021, 4,663,063; 4,708.809; and Russian Patent Application SU1825780 describe amino-phenol compounds as lubricating oil additives (e.g., disp ersant/ detergents) .

US Pat. Nos. 2,511,750; 3,634,248; 4,269,720; 4,335,006; 4,411,805; and 6,242,394 describe certain aniline compounds as stabilizers (antioxidants) for lubricating oil compositions. US Pat. No. 4,778,654 describes alkylaniline/formaldehyde co-oligomers useful as corrosion inhibitors. US Patent Applications 20110224114 & 20100160195 describe morpholine & aniline Derivatives as ashless TBN sources & lubricating oil compositions containing those additives.

EP540534 describes preparation of oil soluble amido amine compounds & further linkage with PIB as an ashless overbased dispersant for the lubricating oil compositions. US patent 5,496,480 details acylation of amino guanidine & further linkage with PIB to provide ashless dispersant for the lubricating oil composition. US patent 7,851,418 also describes salicylation & sulfonation of the active compound to use as ashless TBN booster for the lubricating composition. US patent 4,149,980 describes sulfonation of amino guanidine to impart better acid neutralization capability to lubricating oil.

US Patent No. 7,651,984 discloses a lubricant in the form of a water or oil insoluble solvent in oil emulsion. The water phase contains the basic material, and this phase is dispersed in the oil phase, making it a two phase system.

However all the above mentioned patents and references cited in those patents primarily describe preparation of oil soluble ashless TBN boosting composition by chemical means; where the main active compound is soluble in polar medium (such as water) and insoluble in non polar medium (lubricating oil). The use of guanidium type compound is reported in literature for emulsion based lubricating system for rust inhibition, where the compounds are solubilized in water and emulsified with mineral oil further.

In US patent 20080312340 and 20080229655 reduction of particle size by milling is reported. The patent covers only inorganic compounds more specifically inorganic metal bases. Those inventions further provide a process for preparing the composition and a method for its use. US patent 20080229655 describes the method of preparing a dispersion of metallic base which is highly ash forming. US patent 20080312340 claims to prepare inorganic metallic dispersion such as magnesium oxide, iron oxide, cerium oxide which are all ash forming. All the above processes form ash when dispersed in fuel oils.

In light of the above prior art processes, there exists a need for an ashless additive composition for lubricant oil which does not poison catalytic converters, deposit metal ash in combustion chambers, but has acid neutralization, antirust, anticorrosive, dispersant, and detergent properties in lubricants.

OBJECT AND SUMMARY OF THE INVENTION

It is an object of the invention to provide an ashless lubricant additive for providing a suitable desired Total Base Number (TBN) in a lubricating oil composition/formulation.

It is a specific object of the invention to provide an ashless lubricant additive which can be loaded in high amounts in a lubricating oil composition/formulation.

It is also an object of the present invention to provide an ashless lubricant additive which is stable and provides the desired TBN with desired amount of loading in a lubricating composition/ formulation.

It is a further object of the present invention to provide an ashless lubricant additive which is stable with sufficient clarity that provides the desired TBN with desired amount of loading in a lubricating composition formulation.

To achieve the above objectives, the present invention provides an ashless lubricant additive composition which comprises: (a) 1-60% by wt. of a oil- insoluble nitrogen containing organic compound,

(b) 10-15% by wt. of a surfactant, and

(c) an organic media,

wherein, the said organic compound is nano-dispersed in said organic media.

The present invention also provides a method of preparing an ashless lubricant additive composition comprising

(a) 1-60%) by wt. of a oil- insoluble nitrogen containing organic compound,

(b) 10-15%o by wt. of a surfactant, and

(c) an organic media,

wherein, the said organic compound is nano-dispersed in said organic media. The method comprises reducing the particle size of a slurry comprising (i) the ashless organic compound; (ii) the surfactant; and (iii) the organic media, in the presence of (iv) a plurality of beads, to form a dispersion, wherein the particles are uniformly dispersed in the liquid medium.

The present invention also provides a lubricant oil composition comprising:

(i) a lubricant oil, and

(ii) 0.1 to 60%) of an ashless lubricant additive composition.

The lubricant additive composition in said lubricant oil composition is as per the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a lubricant additive composition and process of preparing the same. The present invention further relates to the lubricant additive composition comprising ashless dispersion of oil insoluble organic compounds. According to the invention, the dispersion is a nanodispersion. According to the invention, the lubricant additive composition comprising ashless nanodispersion of oil insoluble organic compounds is useful as TBN (Total Base Number) booster for lubricating oil compositions. Such lubricant additive is useful for various lubricating oil compositions, particularly engine lubricating oil with reduced levels of sulfated ash (SASH).

The term "lubricant additive" is interchangeably used with "lubricant additive composition" and "lubricant additive formulation". Said term refers to a composition comprising the components (a) an oil-insoluble nitrogen containing organic compound, (b) a surfactant, and (c) an organic media.

The term "lubricating oil composition" is interchangeably used with "lubricating oil formulation". Said term refers to a composition comprising a lubricating oil and the "lubricant additive" of the present invention.

The term "lubricating oil" refers to lubricants useful for lubricating an apparatus in general, and in particular to engine oils for internal combustion engines.

The present invention further provides that the addition of such lubricant additive, is capable of providing basicity to lubricant formulations (lubricant oil compositions); especially low sulfur, low phosphorus, low ash diesel oil formulations, and boosts the TBN level of such lubricating oils.

The present invention provides a lubricant additive that comprises a oil insoluble nitrogen- containing organic compound, a surfactant and an organic media. The organic compound is in the form of a nanodispersion in the organic media.

The nitrogen-containing organic compound can be selected from various derivatives of guanidine. In some embodiments, the nitrogen-containing organic compound is selected from guanidine carbonate; 1 -methyl guanidine carbonate; 1,1 -dimethyl guanidine carbonate; and 1- ethyl guanidine carbonate. In a specific embodiment, the nitrogen-containing organic compound is guanidine carbonate.

The surfactants/dispersants for the lubricant additive can be selected from any conventional surfactants/dispersants used in lubricants. In some embodiments, the surfactants/dispersants are ashless-type molecules used for stabilization of nanoparticles. They do not contain ash- forming metals when added to a lubricant. Dispersants also include polymeric dispersants having hyper reactive polymeric moiety. In the present invention, the ashless dispersants include N-substituted long chain alkenyl succinimides. Examples ofN-substituted long chain alkenyl succinimides include polyisobutylene succinimide with number average molecular weight of the polyisobutylene substituent in the range of 900 to 3000. The polyisobutylene succinimide of different viscosity may be used alone or in various proportions in combination with other dispersants & detergent molecules. Another class of ashless dispersant is Mannich bases. Mannich dispersants are the reaction products of alkyl phenols with aldehydes and amines.

The organic media in which the organic compound is dispersed in a base oil. The base oil may include oils derived from animal sources and vegetable sources (e.g., rapeseed oil, fish oil, coconut oil, castor oil, lard oil), as well as mineral lubricating oils (Group I, Group II, Group III), and solvent-treated or acid-treated mineral lubricating oils of the paraffinic, naphthenic or mixed paraffinic-naphthenic types. The oils may be biodegradable in nature. The polyalphaolefins (PAOs) derived from monomers having from about 4 to about 30 carbon atoms having a viscosity in the range from about 1.5 to about 150 mm7s (cSt) at 100°C can also be used in this invention. The esters of dicarboxylic acids (e.g., adipic acid, phthalic acid, succinic acid etc.) with a variety of alcohols are also useful . The base oil can be an individual oil or may be a mixture of different proportion of these mentioned oils. In specific embodiment, the organic media is low viscosity mineral oil, or low viscosity di-iso decyl di-adipate (DID A), or a mixture thereof.

The present invention also provides that the lubricant additive has a high TBN value, capable of being used in low amounts to achieve desired TBN level in the final lubricant formulations (lubricating oil compositions).

The present invention also provides that the various concentrations of the lubricant additive can be added in varying amounts to a lubricating oil to achieve a lubricating oil composition with a desired TBN.

The amount of lubricant additive required to be added in a lubricating oil composition to achieve a desired TBN can be calculated from the plot shown in Figure 1. Figure 1 shows a plot of TBN vs % Solid Loading of guanidine carbonate, from which the concentration of guanidine carbonate required to get a desired TBN (TBN range 0.6-360) in a lubricating oil composition can be calculated.

Further, according to the present invention, there is provided a process to prepare an over based ashless lubricant additive composition free from metal salts. Further, the invention provides a process to solubilize or disperse large amounts of ashless basic materials (nitrogen containing organic compounds) in lubricant additive.

According to an embodiment of the present invention, there is provided a process for preparing a nanodispersion of organic ashless particles, comprising: reducing the particle size of nitrogen containing organic compound to nano dimension in the presence of (i) a plurality of beads. In an embodiment, the process comprises reducing the particle size of (i) an ashless organic powder; (ii) a surfactant; and (iii) a liquid medium, in the presence of (iv) a plurality of beads, to form a dispersion, wherein the particles are uniformly dispersed in the liquid medium.

In an embodiment of the invention the process comprises preparing a high TBN dispersion of organic base/compound in mineral oil by Small Molecule Surface Modification (SMSM) approach through chemo -mechanical processes.

In an embodiment of the present invention, the surface modification of organic compound particles is done with lubricant formulation compatible dispersant by simultaneous wet ultra- fine grinding. Dispersion of particle with volume average particle size less than 100 nm is acheived with input of substantial energy. The present invention further describes the process of preparing the stable nanodispersion of the active over basing ashless compound in the base oil, which is however insoluble in non polar medium.

Further, the process of the invention for preparing the nanodispersion is devoid of the chemical process and chemicals which generates additional unwanted functionality to make them soluble in oil and are required in large amount. The complete composition comprises of lubricant compatible surfactants/dispersants which further makes the composition seal compatible. The ultrafme (nano) size of the active compound (nitrogen containing organic compound) is hydrophobic ally surface modified to make them stably dispersed in the lubricating oil. The process has the flexibility to prepare the ashless TBN booster in different concentrations as per the requirement of the formulation, with as much as 60% loading.

In an embodiment of the invention, the nanodispersion prepared according to the process of the invention has a total base number (TBN) ranging up to 300 and is opaque or semi- translucent or translucent or transparent depending on solid loading. Further the overbased dispersion prepared by Mechano-activated surface modification with in situ ultrafme grinding had been evaluated for finest particle size achievable, viscosity of the oil & total energy imparted.

In an embodiment of the invention, the lubricant additive can be used for adding in lubricants useful for lubricating apparatus generally, but particularly for use as engine oils for internal combustion engines. These include but are not limited to passenger car engines, small engines, marine diesel engines, stationary gas engines, two-cycle and four-cycle engines, and engines fueled with gasoline, diesel fuel, organic fuels such as alcohol and hydrocarbon- alcohol mixtures, natural gas, and hydrogen, and sump-lubricated and fuel-lubricated engines. It is particularly suited for lubricating heavy duty diesel engines such as the type found in trucks. It is also suited for heavy duty diesel engines which are equipped with exhaust gas recirculation systems. Such systems may be used in efforts to reduce environmental emissions from such engines. Diesel engines with Exhaust Gas Recirculation (EGR) may also experience higher loadings of acidic products of combustion, imparted to the lubricant from the exhaust gases, so lubricants with high TBN levels are often desirable to effect neutralization of such acids.

The lubricating oil composition may also contain other suitable components like detergents, antioxidants, antiwear agents, EP additives, viscosity modifiera, antiscuffmg agents, etc.

As the amounts of phosphorus, sulfur and ash-containing lubricant additives are being reduced to provide mid- and low-SAPS lubricants that are compatible with exhaust gas after- treatment devices, the lubricating oil composition must continue to provide the high levels of lubricant performance, including adequate detergency, and specifications of the OEM's, such as the ACEA E6 and MB p228.51 (European) and API CI-4+ and API CJ-4 (U.S.) specifications for heavy duty engine lubricants. Criteria for being classified as a lubricating oil composition meeting the above listed industry standards is known to those skilled in the art. Following experiments/examples further describe the invention without limiting its scope:

Example 1

Ball mill experiment

A series of dispersions containing an ashless basic/organic compound, an organic medium and a surfactant are prepared from a slurry comprising 40 wt % to 50 wt % of the ashless base, 10 wt % to 15 wt % of a surfactant and for the remaining amount a hydrocarbon fluid, typically low viscosity mineral oil. The slurry is milled in a planetary ball mill with a milling chamber of suitable size appropriate for the scale of the operation. The bead size filling the chamber (typically 33 vol. %) is typically in the range of 0.1 mm to 1 mm diameter (e.g. 0.3 mm+/-0.05 mm beads) with bigger beads being processed first, i.e., first processing with 1 mm bead, then with 0.5 mm & finally with 0.1 mm. After a suitable amount of milling, the required particle size is achieved (i.e. d₅o=100 nm) as determined by Malvern® NanoZS Particle Size Analyzer. The dispersion is easy to pour and stable for several weeks between 20° C and 60° C, showing no tendency to stratify or to form a gel. The preparations prepared as per the example are shown in Table 1.

Table 1

The final sample shows a TBN of 300 as measured in accordance with ASTM D-2896. Example 2

Bead mill experiment

A series of dispersions containing an ashless basic/organic compound, an organic medium and a surfactant are prepared from a slurry comprising 40 wt % to 50 wt % of the ashless base, 10 wt % to 15 wt % of a surfactant and for the remaining amount a hydrocarbon fluid, typically low viscosity mineral oil. 5 kg of the slurry is milled in a combination of horizontal & vertical bead mill with a milling chamber of suitable size appropriate for the scale of the operation. The bead size filling the chamber (typically 70 vol. %) is typically in the range of 0.1 mm to 1 mm diameter (e.g. 0.3 mm+/-0.05 mm beads). The milling with 1 mm bead is done first followed with sequential milling with 0.5 mm bead & 0.1 mm bead. After a suitable amount of milling, typically 4 to 20 minutes residence time (i.e. the actual time the dispersion spends in the mill) the required particle size is achieved (i.e. d₅o=100 nm) as determined by Malvern® NanoZS Particle Size Analyzer. The dispersion is easy to pour and stable for several weeks between 20° C and 60° C, showing no tendency to stratify or to form a gel. The preparations prepared as per example are shown in Table 2.

Table 2

The final sample shows a TBN of 310 as measured in accordance with ASTM D-2896. Example 3

A series of dispersions containing an ashless basic compound, an organic medium and a surfactant are prepared from a slurry comprising 60 wt % of the ashless base, 10 wt % to 15 wt % of a surfactant and for the remaining amount a diester fluid typically low viscosity DIDA (di-iso decyl di-adipate). 5 kg of the slurry is milled in a combination of horizontal & vertical bead mill with a milling chamber of suitable size appropriate for the scale of the operation. The bead size filling the chamber (typically 70 vol. %) is typically in the range of 0.1 mm to 1 mm diameter (e.g. 0.3 mm+/-0.05 mm beads). The milling with 1 mm bead is done first followed with sequential milling with 0.5 mm bead & 0.1 mm bead. After a suitable amount of milling, typically 4 to 20 minutes residence time (i.e. the actual time the dispersion spends in the mill) the required particle size is achieved (i.e. d₅o=100 nm) as determined by Malvern® NanoZS Particle Size Analyzer. The dispersion is easy to pour and stable for several weeks between 20° C and 60° C, showing no tendency to stratify or to form a gel. The preparations prepared as per example are shown in Table 3.

Table 3

The final sample shows a TBN of 360 as measured in accordance with ASTM D-2896.

Refractive index of mineral oil is 1.46-1.48 depending on the viscostiy & polarity of base oil. The RI of guanidine carbonate is 1.47.

Fuzi evaluation: Aging of sample under air at 165° C for extended time interval as shown in Table 4, with the result shown in Figure 2. Table 4

It is found from the table that there is no significant depletion of TBN after extended thermal aging & is comparable with commercial sample.

It may be noted that the embodiments illustrated and discussed in this specification are intended only to teach to those skilled in the art the best way known to the Inventors to make and use the invention. In describing embodiments of the Invention, specific terminology is employed merely for the sake of clarity. However, the invention is not intended to be restricted to specific terminology so-used. The above-described embodiments of the invention may be modified or varied, without departing from the invention, as appreciated by those skilled in the art in light of the above teachings. It is therefore understood that, within the scope of the claims and their equivalents, the invention may be practiced otherwise than as specifically described.

Claims

What Claimed is:

1. An ashless lubricant additive composition comprising:

(a) 1-60% by wt. of an oil- insoluble nitrogen containing organic compound,

(b) 10-15% by wt. of a surfactant, and

(c) an organic media,

wherein, the said organic compound is nano-dispersed in said organic media.

2. The composition of claim 1, wherein the oil- insoluble nitrogen containing organic compound is in an amount of 40-60% by wt.

3. The composition of claim 1, wherein the nitrogen containing organic compound is selected from guanidine carbonate, 1 -methyl guanidine carbonate, 1,1 -dimethyl guanidine carbonate, 1 -ethyl guanidine carbonate, or a mixture thereof.

4. The composition of claim 1, wherein the surfactant is an ashless-type molecule used for stabilization of nanoparticles, selected from N-substituted long chain alkenyl succinimides, Mamilch bases or a mixture thereof.

5. The composition of claim 1, wherein the organic media is selected from oils derived from animal sources, vegetable sources, mineral lubricating oils, solvent-treated or acid-treated mineral lubricating oils of the paraffmic, naphthenic or mixed paraffinic- naphthenic types, poiyalphaolefins (PAOs) derived from monomers having from about 4 to about 30 carbon atoms having a viscosity in the range from about 1 .5 to about 150 mm²/s (cSt) at 100°C, esters of dicarboxylic acids with a variety of alcohols, or a mixture thereof.

6. The composition of claim 5, wherein the organic media is low viscosity mineral oil, or low viscosity di-iso decyl di-adipate (DI D A), or a mixture thereof.

7. The composition of claim 1, wherein the particle size of oil- insoluble nitrogen containing organic compound is d₅o = 100 nm.

8. A method of preparing an ashless lubricant additive composition comprising (a) 1-60% by wt. of a oil- insoluble nitrogen containing organic compound,

(b) 10-15% by wt. of a surfactant, and

(c) an organic media,

wherein, the said organic compound is nano-dispersed in said organic media, the method comprising reducing the particle size of a slurry comprising (i) the ashless organic compound; (ii) the surfactant; and (iii) the organic media, in the presence of (iv) a plurality of beads, to form a dispersion, wherein the particles are uniformly dispersed in the liquid medium.

9. The method of claim 8, wherein the slurry is milled in a planetary ball mill or a combination of horizontal & vertical bead mill, with bead size in the range of 0.1 mm to 1 mm diameter.

10. The method of claim 9, wherein the milling is carried out with bigger beads first, followed by the smaller beads.

11. The method of claim 10, wherein the milling is carried out for a period of about 4 to 20 minutes residence time to achieve the particle size of d₅o=100 nm as determined by Malvern^® NanoZS Particle Size Analyzer.

12. A lubricant oil composition comprising:

(i) a lubricant oil, and

(ii) 0.1 to 60% of an ashless lubricant additive composition comprising:

(a) 1-60% by wt. of a oil- insoluble nitrogen containing organic compound,

(b) 10- 15%) by wt. of a surfactant, and

(c) an organic media,

wherein, the said organic compound is nano-dispersed in said organic media.

13. The composition of claim 12, wherein the lubricant oil is selected from oils derived from animal sources and vegetable sources, as well as mineral lubricating oils (Group I, Group Π, Group III), and solvent-treated or acid-treated mineral lubricating oils of the paraffinic, naphthenic or mixed paraffinic-naphthenic types as well as polyalphaolefins (PAOs) derived from monomers having from about 4 to about 30 carbon atoms having a viscosity in the range from about 1.5 to about 150 mriiV^'s (cSt) at 100°C or the esters of dicarboxylic acids with a variety of alcohols or a mixture thereof.

14. The composition of claim 12, wherein said composition has a Total Base Number (TBN) of from 0.6 to 360.

15. The composition of claim 12, wherein the nitrogen containing organic compound is selected from guanidine carbonate, 1 -methyl guanidine carbonate, 1,1 -dimethyl guanidine carbonate, 1 -ethyl guanidine carbonate, or a mixture thereof.

16. The composition of claim 12, wherein the surfactant is an ashless-type molecule used for stabilization of nanopartieles, selected from N-substituted long chain alken l succiniraid.es, Manmch bases or a mixture thereof.

17. The composition of claim 12, wherein the organic media is selected from oils derived from animal sources, vegetable sources, mineral lubricating oils, solvent-treated or acid-treated mineral lubricating oils of the paraffinic, naphthenic or mixed paraffinic- naphthenic types, polya!phao!efms (PAOs) derived from monomers having from about 4 to about 30 carbon atoms having a viscosity in the range from about 1.5 to about 150 mm²/s (cSt) at 100°C, esters of dicarboxylic acids with a variety of alcohols, or a mixture thereof.

18. The composition of claim 17, wherein the organic media is low viscosity mineral oil, or low viscosity di-iso deeyl di-adipate (DIDA), or a mixture thereof.

19. The composition of claim 12, wherein the particle size of oil-insoluble nitrogen containing organic compound is d₅o = 100 nm.

20. The lubricating oil composition of claim 12, further comprising a detergent, an antioxidant, an antiwear agent, an EP additive, a viscosity modifier, an antiscuffing agent, or a mixture thereof.