FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patent Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
"FUEL COMPOSITIONS COMPRISING CETANE AND LUBRICITY
IMPROVERS AND PROCESSES FOR PREPARATION OF CETANE AND
LUBRICITY IMPROVERS THEREOF"
We, BHARAT PETROLEUM CORPORATION LIMITED, of Bharat Bhawan, 4 & 6 Currimbhoy Road, Ballard Estate, Mumbai- 400 001, India.
The following specification particularly describes the nature of the invention and the manner in which it is performed:

FUEL COMPOSITIONS COMPRISING CETANE AND LUBRICITY IMPROVERS AND PROCESSES FOR PREPARATION OF CETANE AND LUBRICITY IMPROVERS THEREOF
FIELD OF THE INVENTION
The invention relates to cetane and lubricity improvers, particularly the invention relates to fuel compositions containing such cetane and lubricity improvers. The invention also relates to improved process for the preparation of cetane and lubricity improvers. More particularly the invention relates to cetane and lubricity improvers derived from natural, renewable triglycerides, esters and alcohols thereof and are environment friendly. BACKGROUND AND PRIOR ART OF THE INVENTION
Five important properties associated with premium quality diesel fuel are (1) Energy content, (2) cetane number, (3) fuel injector cleanliness, (4) low temperature operability and (5) thermal stability. Among these the most important property determining the diesel fuel quality is cetane number.
Cetane number is related to ignition delay after the fuel is injected into the combustion chamber, i.e. it measures the readiness of a fuel to auto-ignite. High cetane number means the fuel will ignite rapidly in the engine, it however does not mean that the fuel is highly flammable or explosive. A short ignition delay results in smooth engine operation and decreases the particulate matter. The reduction in the sulfur content of diesel fuel these days has resulted in lubricity problems and reduced cetane number, because reduction of sulfur is accompanied by a reduction in polar oxygenated compounds and polycyclic aromatics including nitrogen containing compounds, therefore reduced boundary lubricating ability of severely refined fuels. Low sulfur fuels

have also been found to increase the sliding adhesive wear and fretting wear of pump components such as rollers, couplings, lever joints and shaft drive bearings. Diesel fuel must meet minimum lubricity requirements to protect components such as fuel injector pumps and fuel injectors against premature wear and tear. To overcome these problems additives are added to diesel fuels or middle distillate fraction which can provide enhanced fuel efficiency and smooth engine operation.
Cetane Improvers (hereinafter referred to as "CIs ") are specialty chemicals that, when added to diesel fuel or middle distillate fraction enhance the cetane number of the fuel and simultaneously reduce NOx and particulate matter emissions from a fuel engine. CIs are also capable of modifying the performance of alternative fuels such as ethanol so they can be used in diesel engines without significant engine modification. While CIs increase the ignition quality of diesel fuel or middle distillate fraction, lubricity improvers are extremely important to minimize wear between moving metal parts in diesel fuel injectors.
The efficiency of the CIs is attributed to their ability to contribute and assist in free radical generation during the ignition. Compounds such as certain peroxides, aldehydes, organic sulfides and lower alkyl nitrates have been used for this purpose. Many of these compounds are yield unsatisfactory results due to instability, undesirable lowering of flash point or due to their tendency to form corrosive gases on storage. Long fatty chain structure combined with alkyl nitrate chain functionality yields a product potentially meeting the targeted properties of a cetane improver. The combination of polar head group and long chain hydrocarbon of the fatty acid compound also increases lubricity, thus imparting a dual functionality. Cetane and

lubricity improvers based on fatty esters are biodegradable natural products and are supposed to be more resistant to shock and Fire initiated detonation. In addition, triglycerides have 71 bonds and ester functionality which can easily be modified and can lead to desired products.
Nitrates and peroxides are historically been the chemical functional groups that lead to good cetane improver performance. US patent application number 0037598Al describes CIs based on triglycerides and petroleum fractions which are at least half as effective as commercial cetane and lubricity improvers.
U.S. Patent No.6,589,302 Bl relates to an additive concentrate comprising glycerides of unsaturated fatty acids and at least one alkanolamine. The product remains fluid, is stable at low temperature and improves lubricity, thereby enhancing fuel economy and minimizing engine deposits.
U.S. Patent No. 4,365,973 discloses CIs comprising paraffinic nitrate or a mixture of nitrate wherein the paraffinic group contains from 4 to 16 carbon atoms.
U.S. Patent No. 4,448,587 describes synergistic combination of (a) an alkyl-nitrate (e.g. octyl nitrate) and (b) the nitrate ester of an alkoxylated alcohol (e.g.ethoxyethyl nitrate).
Unfortunately, some compounds that are effective cetane improver are also sensitive explosives. Therefore, they are not commercially accepted and attempts were made to desensitize them by blending with inert solvents. But these blends are less effective than the original compound and also give an additional cost in shipping and storage.

Smith et. al. (U.S. Patent No. 4,447,246) reported an improvement in the cetane number of diesel fuels by the addition of a small amount of a dithiocarbamate or a sulfonamide compounds viz.,allyl-N,N-dimethylthiocarbamate and N,N-dimethyl-S-t-butyl sulfenyldithiocarbamate.
EP 157684 discloses nitrates of alkoxylated alcohols or phenols added to diesel fuels to improve cetane index and to keep fuel injector systems clean. The organic nitrate is of the formula R(OCH2CHX)nON02 where R is C6-C20 alkoxyl or aryl substituted by a C4-C18 alkyl chain., X is H, CH3 and n= 1-15, R is a radical derived from aliphatic monoalcohol of natural or synthetic origin such as hexanol, octanol, myristyl or styryl alcohol or alcohols from the oxo process.
U.S. Patent No. 5,454,842 describes many approaches to the conversion of fatty acids into nitrated CIs. Feed stocks used here are fatty acid rich tall oil, vegetable oils and mixtures thereof. Fatty alcohols were produced by reduction of the ester of fatty acid groups to an alcohol by sodium in ethanol which was then nitrated to form a fatty nitrate ester.
WO93/08244 document discloses cetane improving additives comprising 13-25 carbon alkyl nitrates. Nitrates are obtained by nitration of oxo process alcohols. The fuel contains alkyl nitrate in addition to an ashless dispersant preferably a macrocyclic polyamine dispersant.
Alcantara R et al. (Alcantara R et al, Biomass and bioenergy 18, 2000, 515-527) discusses that amide biodiesel synthesized from fatty materials like soyabean oil, used frying oil and tallow have been found to increase the cetane number of petrochemical diesel fuel. Amidation reactions carried out with diethyl amine in the

presence of sodium methoxide as catalyst are disclosed. The process for synthesizing biodiesel amide reported in Alcantara et.al. is lengthy and time taking process. In this process the reaction time for the preparation of amide from biodiesel is as long as 48h; and the product hence obtained is miscible with the byproduct (glycerol). Separation and isolation of the biodiesel amide from the byproduct (glycerol) using vacuum distillation method is also cumbersome and an * energy intensive process. Disadvantage of prior art fuel additives:
All the above mentioned prior art fuel additives achieve successes as cetane improvers only in some aspects but fail or perform less in other aspects. Also, the prior art processes for the synthesis of cetane improvers either involve multi-step energy intensive processes, or have limited solubility, or are explosive in nature or use very costly catalyst (which can't be used industrially for large scale production), etc.
Accordingly, there is a continuous need in this field of technology to provide an improved fuel additive that can improve combustion and at the same time is also cost effective.
The present invention provides for Cetane Improvers (CIs) derived from triglycerides, esters or alcohols that improve diesel fuel or middle distillate fraction performance by improving cetane number and lubricity of the fuel at same dosage level.
The present invention also provides for improved method of preparation of CIs, i.e. either amides or nitrates of the present invention through amidation and nitration, respectively of triglycerides, esters or alcohols thereof.

OBJECTS OF THE INVENTION
The primary object of the invention is to provide for fuel compositions containing cetane and lubricity improvers in the base fuel having enhanced cetane number and lubricity properties.
Another object of the invention is to provide for cetane improvers and lubricity improvers derived from natural, renewable and environment friendly triglycerides and thereby providing biodegradable, renewable and environment friendly cetane improvers and lubricity improvers.
Yet another object of the invention is to provide for Cetane Improvers that improve base fuel performance by improving cetane number and lubricity of the fuel at same dosage level.
Yet another object of the invention is to provide for improved processes for the preparation of CIs, i.e. either amides or nitrates through amidation and nitration, respectively of triglycerides, esters or alcohols thereof. SUMMARY OF THE INVENTION
Accordingly, the present invention relates to a fuel composition comprising: (a) at least 99 wt% of a base fuel, and (b) cetane improvers selected from fatty amide or fatty alcohol nitrate ester in the concentration range of 0.02 to 0.2 wt%.
In a preferred embodiment, the base fuel in the fuel composition of the invention is diesel or middle distillate fraction.
In another preferred embodiment, the said fatty amide in the fuel composition of the invention is in the concentration range of 0.05 to 0.2 wt%, preferably in the concentration range of 0.05 to 0.15 wt%.

In yet another preferred embodiment, the said fatty alcohol nitrate in the fuel

composition of the invention is in the concentration range of 0.025 to 0.1 wt%.
In yet another preferred embodiment, the said fatty amide in the fuel composition of the invention is derived from triglycerides, methyl ester of fatty acids, and/or mixtures thereof, wherein the triglycerides or methyl esters are obtained from Jatropha oil and/or soyabean oil or a mixture thereof.
The present invention also relates to a process for the preparation of fatty amide comprising reacting diethyl amine with triglycerides or methyl esters thereof in presence of metal oxides for a time period of l8-22hrs, preferably for 20 hrs, at a temperature of 180-200 C, preferably at 190 C to obtain a final product; and wherein further the byproduct glycerol, if produced, is separated from the final product by crystallization or pH method, wherein the triglycerides or methyl esters are preferably obtained from Jatropha oil and/or soyabean oil or a mixture thereof.
In a preferred embodiment, the metal oxides used in the process for the preparation of fatty amide are freshly prepared oxides of zinc, strontium or antimony, preferably zinc oxide.
In another preferred embodiment, the byproduct glycerol produced in the process for the preparation of fatty amide is separated from the final product by crystallization at a temperature in the range of 0-4C.
In yet another preferred embodiment, the byproduct glycerol produced in the process for the preparation of fatty amide is separated from the final product by treating the said product with aqueous HC1 and the pH is adjusted in the range of 5 to 6.

The present invention also relates to a process for the preparation of fatty alcohol nitrate comprising nitration of fatty alcohols using concentrated nitric acid and acetic anhydride to obtain fatty alcohol nitrate ester, wherein the said fatty alcohols are obtained by reduction of methyl esters of vegetable oils by sodium borohydride in a polar solvent, preferably an alcohol having carbon atoms CI to C4 or their mixtures thereof, more preferably CI and C2 alcohols and mixtures thereof.
In a preferred embodiment, the said polar solvent used in the process for the preparation of fatty alcohol nitrate is methanol and ethanol in the ratio 8:2.
In another preferred embodiment, the sodium borohydride used in the process for the preparation of fatty alcohol nitrate is added in molar equivalents to the reactant methyl esters. DETAILED DESCRIPTION OF THE INVENTION
The fuel additives, i.e. cetane improvers and lubricity improvers of the present invention are derived from natural, renewable triglycerides and are environment friendly product. Fuel compositions containing such Cetane Improvers (CIs) comprises a fatty amide or a fatty alcohol nitrate ester; which are derived from triglycerides, mixtures thereof or methyl ester of fatty acids. CIs of the present invention also exhibit very good lubricity improver properties when added to fuels in same concentration range as required for cetane improvement.
The present invention also discloses improved methods for preparation of:
(a) Amides derived from long chain fatty acid esters and triglycerides e.g. Jatropha oil, karanja oil and soyabean oil, and
(b) nitrated products derived from long chain fatty acid esters and triglycerides.

These nitrated and amidated CIs have been found to enhance lubricity of base fuel by 25-75 units and cetane number by 2-5.4 units.
A preferred embodiment of the invention is to provide for Cetane Improvers (CIs) which improve the cetane number with an additional advantage of being lubricity improver at the same concentration, i.e. in the range of 0.02 to 0.2 wt%. The cetane improver composition comprises of amides prepared from triglycerides of natural origin or mixture thereof having C8 to C18 carbon atoms.
The CIs of the present invention are used to prepare a diesel fuel or middle distillate fraction composition comprising cetane improvers selected from fatty amide or fatty alcohol nitrate ester in the concentration range of 0.02 to 0.2 wt%. The fuel composition of the present invention comprises the said fatty amide in the concentration range of 0.05 to 0.2 wt%, preferably in the concentration range of 0.05 to 0.15 wt%. The fuel composition of the present invention comprises the said fatty alcohol nitrate preferably in the concentration range of 0.025 to 0.1 wt%.
Processes of preparation of CIs (fatty amides and fatty alcohol nitrate ester): (1) Preparation of fatty amides:
As mentioned hereinbefore, the earlier attempts (Alcantara et.al) to synthesize biodiesel amide were lengthy and time taking processes. In prior art processes the reaction time for the preparation of amide from biodiesel was about 48h; and the product hence obtained was miscible with the byproduct (glycerol). Separation and isolation of the biodiesel amide from the byproduct (glycerol) using vacuum distillation method is cumbersome and an energy intensive process.

The fatty amides (CIs) of the present invention are synthesized by the reaction of diethyl amine with the triglycerides or methyl esters thereof in presence of metal oxides. The metallic oxides used in the reaction are freshly prepared oxides of zinc, strontium or antimony, preferably zinc oxide.
The triglyceride used in present invention is Jatropha oil and methyl ester of the Jatropha oil of their mixtures thereof. Fattty acids and oils have been esterified by the reaction of alcohol such as methanol in the presence of acid such as sulfuric acid or base such as NaOH or KOH at reflux temperature, see J.Org. Chem. 50,8 (1985).
The present invention describes processes for the synthesis of amide biodiesel in less reaction time, i.e. (18-22hrs), either with no byproduct or with much simpler method for separation of the byproduct.
The present invention provides for two approaches to overcome the elimination/separation of byproduct glycerol. First approach relies on the crystallization while second approach is based on pH separation. In the present invention both the processes result in efficient separation of glycerol. In order to separate glycerol from the final product the crystallization is done at low temperatures, i.e. in the range of 0-4°C and pH separation is done by treating it with aqueous HC1 and the pH is adjusted in the range of 5 to 6. Biodiesel amide synthesized with biodiesel and diethylamine under above conditions does not produce glycerol at all. The reaction can be completed in 18-22hrs, preferably in 20 hrs and at a temperature of 180°-200°C, preferably at 190°C.
(2) Preparation of fatty alcohol nitrate ester:

The present invention also provides for a process for the synthesis of the fatty alcohol nitrate ester (CIs) from fatty alcohols. The fatty alcohols are obtained by reduction of methyl esters of vegetable oils by sodium borohydride in a polar solvent preferably an alcohol having carbon atoms CI to C4 or their mixtures thereof, most preferably CI and C2 alcohols and mixtures thereof. The alcohols so produced are "further nitrated by the procedures described earlier using concentrated nitric acid and acetic anhydride (See, GJSuppes, Ind.Eng.Chem.Res.2003, 42, 5042-5053).
The alcohol used here is methanol and ethanol in the ratio 8:2, because when one solvent is used the reaction does not proceed towards completion. In this reaction equal molar equivalents of sodium borohydride is added to the substrate or reactant.
Reduction of esters to alcohol has been achieved by hydrogenation using rhenium heptoxide as catalyst as disclosed by Broadbent et al. or by hydrogenation using copper chromate or Raney-nickel as catalyst followed by Bouveault-Blanc method and followed by nitration of resulting alcohols.
Fuel composition containing from 0.02 to about 0.2wt% preferably 0.05 to 0.2wt%, more preferably 0.05 to 0.15wt% of fatty amide as CIs or containing 0.025 to 0.1 wt% fatty alcohol nitrate as CIs in addition to a base fuel shows improvements in cetane rating as well as lubricity, Cetane number of the fuel increases from 0.5 to > 5 depending on the concentration of additive and type of the base fuel used. The lubricity aid of the CIs of this invention has been found to be extremely well suited to low sulfur diesel fuel with a very low dosage providing excellent lubricity. A significant increase in lubricity has been observed when the CIs are added at a concentration of 0.025 to 0.1wt%. The lubricity of the products was tested by HFRR (PCS Instruments).

MAIN ADVANTAGES OF THE INVENTION
1. The cetane improvers of the present invention also exhibit very good lubricity properties when added to diesel fuel or middle distillate fractions in same concentration range as required for cetane improvement.
2. Cetane improvers and lubricity improvers of the present invention are derived from natural, renewable triglycerides and are environment friendly.
3. Fatty amides (CIs) of the present invention have been synthesized in less reaction time (18-20hrs) using freshly prepared metal oxides of zinc, strontium and antimony.
4. Byproduct glycerin, when produced during synthesis of fatty amides have been removed either by crystallization method or by drop wise addition of aqueous hydrochloric acid till two layers of glycerin and amide are separated.
5. To overcome problem of glycerin separation, fatty amides (CIs) of the present invention have been prepared from esters of triglycerides where methanol is formed as byproduct which is easier to remove from the synthesized amide leading to better purity of the product.
6. In the present invention, the preparation of precursor of fatty alcohol nitrate ester (CIs) of is an improved process wherein the reduction of fatty acid ester has been carried out using sodium borohydride in alcohol at 10°C to 25°C.

EXAMPLES
The following examples describe preferred embodiments of the invention. The specific examples given herein, however, should not to be construed as forming the only genus that is considered as the invention, and any combination of the process or their steps may itself form a genus. Other embodiments within the scope of the claims herein will be apparent to one skilled in the art from consideration of the specification or practice of the invention as disclosed herein.
The lubricity and cetane improving properties of the CIs of the present invention are summarized in Table-1 and Table-2 respectively. Example-1
Typically, a 300 mL autoclave is charged with 30g Jatropha oil, diethyl amine (15g) and catalyst zinc oxide 2-3% (w/w of oil). The reaction is carried out at predetermined temperatures of 180 -200 C, and at 10 bar pressure. At constant pressure conditions, heating and stirring functions of the autoclave are switched off, and the mixture is cooled. Reaction mixture is centrifuged and liquid is separated from the solid catalyst. Excess diethyl amine is evaporated under reduced pressure and glycerol is separated by crystallization at 3°C. Clear dark brown product is isolated and characterized by FTIR and !H NMR spectroscopic methods. Example-2
Typically, a 300 mL autoclave is charged with 30g Jatropha oil, diethyl amine (12g) and catalyst zinc oxide 2-3% (w/w of oil). The reaction is carried out at predetermined temperatures of 180 -200 C and at 10 bar pressure. At constant pressure conditions, heating and stirring functions of the autoclave are switched off, and the

mixture is cooled. Reaction mixture is centrifuged and liquid is separated from the solid catalyst. Excess diethyl amine is evaporated under reduced pressure. Glycerol is separated by adjusting the pH in the range of 5 to 6 using aqueous HC1. The yellow product is isolated and characterized by FTIR and 'H NMR spectroscopic methods. Examplc-3
Typically, a 300 mL autoclave is charged with 25g of methyl ester of soyabean oil, diethyl amine (15g) and catalyst zinc oxide 2-3% (w/w of oil). The reaction is earned out at predetermined temperatures of 180-200 C and at 10 bar pressure. At constant pressure conditions, heating and stirring functions of the autoclave are switched off, and the mixture is cooled. Reaction mixture is centrifuged and liquid is separated from the solid catalyst. Excess diethyl amine is evaporated under reduced pressure. Clear dark brown product is isolated and characterized by FTIR and !H NMR spectroscopic methods. Exampte-4
Preparation of fatty alcohol from biodiesel
(a) In a three necked flask biodiesel of soyabean oil (lOg) is taken in 20 mL methanol and ethanol (8:2) and the temperature is maintained around IOC. 1.1 equivalent of sodium borohydride is added in small fractions while maintaining the temperature at around 10°-15°C.
After complete addition reaction mixture is stirred for 6 hrs. The reaction is quenched with water, washed with water, brine and dried on anhydrous sodium sulfate. Light yellow color product is obtained which is nitrated further as per procedure

described hereinafter. Yellow color product is obtained (yield: >90%) which is then analyzed by elemental analysis, IR and !H NMR. Preparation of fatty alcohol nitrate ester
(b) In a 100 mL three necked flask equipped with thermometer, magnetic stirrer and dropping funnel is charged with alcohol obtained after reduction of methyl ester of fatty acid (10 g) and acetic anhydride (18.3g). The reaction mixture is stirred while the reaction temperature is maintained at 10 C by an external ice bath. Nitric acid (11 mL) is added slowly to this mixture using a dropping funnel with constant stirring while controlling the temperature of reaction at IOC.
After complete addition mixture is stirred for 4 hrs. The reaction is quenched with ice cold water, washed with water, sodium bicarbonate and dried over anhydrous sodium sulfate. Dark red color product is obtained (yield: >90%) which is analyzed by IR which shows strong peaks at 1634, 1275, S56 cm"1 that are representative of nitrate group. Incorporation of nitrogen is further confirmed by elemental analysis which shows 3.74% nitrogen.
Table-1. Improvement in Lubricity of the base fuel with different additives.

S.No. Additive Dosage (ppm) Lubricity, wear scar,
micron
1. Base Fuel - 256
2. Biodiesel Amide from Methyl ester of Soyabean oil 1000 216
3. Fatty alcohol nitrate ester 1000 185
4. Biodiesel Amide from 1000 231
Jatropha oil

Table-2. Increase in Cetane number of the base fuel with different additives.

S.No. Additive Dosage (ppm) Cetane no. A Cetane no.
1. Base fuel - 48,6 -
2. Biodiesel Amide from Soyabean oil ester 1000 50.0 1.4
3. Biodiesel Amide from Soyabean oil ester 2000 50.8 2.2
4. Biodiesel amide from Jatropha oil 1000 49,4 0.8
5. Biodiesel amide from Jatropha oil 2000 50.6 2.0
6. Base Fuel - 45.5 -
7. Fatty alcohol nitrate ester 1000 50.0 4.5
8. Fatty alcohol nitrate ester 2000 50.9 5.4

We Claim:
1. A fuel composition comprising:
(a) at least 99 wt% of a base fuel, and
(b) cetane improvers selected from fatty amide or fatty alcohol nitrate ester in the concentration range of 0.02 to 0.2 wt%.

2. The fuel composition as claimed in claim 1, wherein the base fuel is diesel or middle distillate fraction.
3. The fuel composition as claimed in claims 1 or 2, wherein the said fatty amide is in the concentration range of 0.05 to 0.2 wt%, preferably in the concentration range of0.05to0.15wt%.
4. The fuel composition as claimed in claims 1 or 2, wherein the said fatty alcohol nitrate is in the concentration range of 0.025 to 0.1 wt%.
5. The fuel composition as claimed in any preceding claim, wherein the said fatty amide are derived from triglycerides, methyl ester of fatty acids, and/or mixtures thereof.
6. The fuel composition as claimed in any preceding claim, wherein the triglycerides or methyl esters are obtained from Jatropha oil and/or soyabean oil or a mixture thereof.

7. A process for the preparation of fatty alcohol nitrate ester as claimed in claim 1, comprising nitration of fatty alcohols using concentrated nitric acid and acetic anhydride to obtain fatty alcohol nitrate ester, wherein the said fatty alcohols are obtained by reduction of methyl esters of vegetable oils by sodium borohydride in a polar solvent, preferably an alcohol having carbon atoms CI to C4 or their mixtures thereof, more preferably CI and C2 alcohols and mixtures thereof.
8. The process as claimed in claim 7, wherein the said polar solvent is methanol and ethanol in the ratio 8:2.
9. The process as claimed in claims 7 or 8, wherein said sodium borohydride is added in molar equivalents to the reactant methyl esters.