WO2015015415A1

WO2015015415A1 - Process for obtaining ester

Info

Publication number: WO2015015415A1
Application number: PCT/IB2014/063512
Authority: WO
Inventors: Chinnamma MOHANKUMAR; Salini BHASKER; Harish MADHAV; Rajesh Mankulathil DEVASSY
Original assignee: Scms Institute Of Bioscience And Biotechnology Research And Development
Priority date: 2013-07-29
Filing date: 2014-07-29
Publication date: 2015-02-05

Abstract

The present disclosure relates to a process for obtaining ester and optionally glycerol from Coconut. The present disclosure also relate to the ester obtained and its use as a biofuel as an alternative for diesel. The process comprising acts of: a) obtaining endosperm from plant source and extracting oil from the endosperm, b) pretreating the oil and adding catalyst to the pre-treated oil to obtain reaction mixture, c) treating the reaction mixture to obtain ester fraction and glycerol fraction, wherein the glycerol fraction is heavier than the ester fraction, d) separating 25 the ester fraction from the glycerol fraction, obtaining and optionally quantifying ester from the ester fraction, and e) optionally obtaining and optionally quantifying glycerol from the glycerol fraction; methyl ester obtained from the said process.

Description

"PROCESS FOR OBTAINING ESTER"

TECHNICAL FIELD

The present disclosure relates to a process for obtaining Ester and glycerol from coconut, preferably coconut oil. The present disclosure also relates to the Ester obtained and its use as a biofuel as an alternative for diesel.

BACKGROUND OF THE DISCLOSURE

Self-sufficiency in energy requirement is a critical factor for the success of any growing economy. With respect to the increasing rate of energy consumption, dependence on fossil fuels will necessarily have to be reduced. India as the 5^th largest energy consumer, is importing almost 70% of its crude oil requirement (90 million tonnes) and the statistics indicate that this trade would rise to 95% by 2030. It is a paradox that with a rich natural biomass resource that can be converted in to renewable energy, the import trade of the country for petroleum product remains exorbitant. Hence, the search for new alternative source for fuel from nature, that is renewable, safe and non-polluting has become a part of innovative research today. Even though, different research agencies of the country have made several attempts in the production of biodiesel from oil crops under national mission on biodiesel by ministry of rural development, none of them have come out at commercial level with accepted technical feasibility with that of diesel. Hence, in view of constant increase in the price of diesel, scientists are tempted to identify attractive source of alternative energy.

Many researchers have successfully worked on generating energy from different alternative sources including solar and biological sources for production of electricity and fuel. Fuel and energy crisis due to depletion of non-renewable energy resources has generated a special interest in conversion of agriculture products to biofuel. India has a good number of oleaginous crops that can yield oil both for domestic and industrial purposes. As a renewable energy resource, vegetable oils and their derivatives are one of the most promising alternative for making biofuel. The use of vegetable oil in a combustion ignition engine (CIE) was first demonstrated by using peanut oil in diesel engine. The direct use of oils from peanut, coconut, soybean, sunflower, palm oil, linseed oil, rape seed oil have been attempted by many researchers. However, due to technical constraints for long term use of vegetable oils, such as sticking on piston ring, owing to their higher viscosity and other physicochemical features, their usage in engines' for long term is limited. Since trans-esterification process of the oil for making esters was found more compatible with the properties of fuel, the esterification process of vegetable oils have been tried in the production of biofuels.

The nutritional, therapeutic and industrial qualities of coconut oil, the commercial viability of non-lipid components of coconut and the perennial nature of yielding of the coconut palms make the crop unique from other tropical oleaginous crops. The main focus of the previous reports on production of biofuel from coconut oil was the trans-esterification of the oil to ethyl and methyl esters for blending it with diesel in vehicles. However, there are no studies relating to trans-esterification of coconut oil, esters having physicochemical properties and technical feasibility of fuel quality. Therefore, a detailed analysis of the coconut oil and its esters is inevitable for determining the functional efficacy of Coconut Methyl Ester as biofuel. In light of foregoing discussion, there exists a need to develop simple, efficient and economical method for producing biofuel from a renewable source. The present disclosure overcomes the various drawbacks observed in the prior art.

STATEMENT OF THE DISCLOSURE

Accordingly, the present disclosure relates to a process for obtaining ester optionally along with glycerol, said process comprising acts of: a) obtaining endosperm from plant source and extracting oil from the endosperm, b) pretreating the oil and adding catalyst to the pre-treated oil to obtain reaction mixture, c) treating the reaction mixture to obtain ester fraction and glycerol fraction, wherein the glycerol fraction is heavier than the ester fraction, d) separating the ester fraction from the glycerol fraction, obtaining and optionally quantifying ester from the ester fraction, and e) optionally obtaining and optionally quantifying glycerol from the glycerol fraction; methyl ester obtained from the said process; and use of methyl ester obtained by the said process as a biofuel. BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES

In order that the disclosure may be readily understood and put into practical effect, reference will now be made to exemplary embodiments as illustrated with reference to the accompanying figures. However, the figures are purely for the purpose of exemplifying and are non-limiting in nature. The figures together with the detailed description below, are incorporated in and form part of the specification, and serve to further illustrate the embodiments and explain various principles and advantages, in accordance with the present disclosure where:

Figure 1 shows flow diagram of experimental setup for the production of Coconut Methyl ester from coconut oil.

Figure 2 shows protocol for oil production.

Figures 3a & 3b show the effect of methanol and NaOH on yield of CME respectively.

Figure 4 shows the effect of temperature on yield of CME.

Figures 5a & 5b show the power and torque of CME as a biofuel respectively.

DETAILED DESCRIPTION OF THE DISCLOSURE

The present disclosure relates to a process for obtaining ester optionally along with glycerol, said process comprising acts of:

a) obtaining endosperm from plant source and extracting oil from the endosperm;

b) pretreating the oil and adding catalyst to the pre-treated oil to obtain reaction mixture; c) treating the reaction mixture to obtain ester fraction and glycerol fraction, wherein the glycerol fraction is heavier than the ester fraction;

d) separating the ester fraction from the glycerol fraction, obtaining and optionally quantifying ester from the ester fraction; and

e) optionally obtaining and optionally quantifying glycerol from the glycerol fraction.

In an embodiment of the present disclosure, the plant source is selected from group comprising Cocos nucifera, preferably coconut. In another embodiment of the present disclosure, the endosperm is obtained by separating it from the plant source, optionally grating and drying the endosperm; and wherein the drying of the endosperm is at temperature ranging from about 50°C to about 100°C, preferably about 60°C to about 90°C, for time duration ranging from about 30 minutes to about90 minutes, preferably about 60 minutes.

In yet another embodiment of the present disclosure, the oil has free fatty acid content ranging from about 0.1% to about 1.5%, preferably about 1% and moisture content ranging from about 1% to about 3%, preferably about 1%; wherein the extracting of oil is carried out in expeller machine; and wherein the pretreating of the oil is carried out at temperature ranging from about 85°C to about 95°C, preferably about 90°C for time duration ranging from about 20 minutes to about 30 minutes.

In still another embodiment of the present disclosure, the treating comprises acts of:

a) agitating the reaction mixture at about 700 rpm to about 1000 rpm, preferably about 800 rpm after addition of the catalyst for time duration ranging from about 30 minutes to about 90 minutes, preferably about 50 minutes;

b) refluxing the mixture for time duration ranging from about 60 minutes to about 80 minutes, preferably about 75 minutes, at temperature ranging from about 60°C to about 90°C, preferably about 76°C; and

c) cooling at temperature ranging from about 25°C to about 35°C, preferably about 30°C for time duration ranging from about 8 hours to about 10 hours, preferably about 9 hours to obtain the ester fraction and the glycerol fraction.

In still another embodiment of the present disclosure, the catalyst is alcohol-alkali catalyst, wherein the alcohol is selected from group comprising methanol, ethanol or any combinations thereof, preferably methanol at amount ranging from about 10 v/v % to about 20 v/v %, preferably about 15 v/v %; and the alkali is selected from group comprising sodium hydroxide, potassium hydroxide or any combinations thereof, preferably sodium hydroxide at amount ranging from about 0.5 w/v % to about 1.5 w/v %, preferably about 1 w/v %. In still another embodiment of the present disclosure, the catalyst is alkoxide such as methoxide, preferably sodium methoxide; and wherein the catalyst is optionally freshly prepared catalyst.

In still another embodiment of the present disclosure, yield of the ester and the glycerol is at ratio of about 8:2 to about 9: 1 , preferably about 9: 1.

In still another embodiment of the present disclosure, the separating is carried out by incubating for time duration ranging from about 6 hours to about 12 hours, preferably for about 8 hours to about 10 hours.

In still another embodiment of the present disclosure, the ester is methyl ester; and wherein the ester is obtained by subjecting the ester fraction to acts comprising washing, vacuum heating at temperature ranging from about 80°C to about 120°C, preferably about 100°C or any combination thereof

In still another embodiment of the present disclosure, the glycerol is obtained from the glycerol fraction by subjecting to pH ranging from about 4 to about 7, preferably to pH of about 5 to about 6, and precipitation.

The present disclosure also relates to Methyl Ester obtained from the process as said above.

In an embodiment of the present disclosure, the ester is used as biofuel.

In another embodiment of the present disclosure, said biofuel is used as automotive fuel.

In another embodiment of the present disclosure, said biofuel is used as automotive fuel in diesel engine.

The present disclosure relates to a process for obtaining Coconut Methyl Ester (CME) and optionally glycerol from coconut, preferably coconut oil. The present disclosure also relates to the Coconut Methyl Ester obtained and uses thereof.

The present disclosure relates to producing biofuel from coconut. In an embodiment, the present disclosure relates to producing biofuel from coconut, coconut oil by preparing coconut methyl ester.

In an embodiment, the present disclosure relates to obtaining biofuel for diesel engine. In another embodiment, the present disclosure standardizes CME and glycerol production from coconut oil. In another embodiment, the present disclosure analyzes the physicochemical features of CME for determining its technical feasibility as biofuel.

In another embodiment of the present disclosure, the CME obtained has physicochemical features rendering it feasible for use as a biofuel. In an exemplary embodiment of the present disclosure, the CME obtained has physicochemical features rendering it feasible for use as a biofuel in diesel engine.

In another embodiment of the present disclosure, the CME is obtained from coconut oil by trans-esterification process.

The present disclosure relates to producing biofuel from coconut oil by preparing coconut methyl ester by transesterifcation process. Appropriate standardization is done in the parameters viz, amount of alcohol, percentage of alkali, temperature, speed of agitation, purification procedure and the yield of CME and glycerol. Further, the quality of the ester is compared with biodiesel standard in order to ascertain its efficacy for using as an alternative source of fuel.

The present disclosure also relates to a method for production of CME from coconut oil using alcohol such as methanol or ethanol and alkali such as sodium hydroxide or potassium hydroxide as catalyst, wherein percentage of alcohol and alkali, preparation of the alkoxide such as methoxide, duration of the transesterifcation reaction, temperature, and rotating speed of the vessel are critical features for maintaining quality of the CME as a biofuel.

The amount of alcohol required for the transe-sterification (TE) reaction of the oil is about 5 v/v % to about 25 v/v %, preferably about 10 v/v % to about 20 v/v %, more preferably at about 15 v/v % with alkali at an amount of about 0.5 w/v % to about 1.5 w/v %, preferably about 0.75 w/v % to about 1.25 w/v %, more preferably at about 1 w/v %. In a non-limiting embodiment, the alcohol is selected from a group comprising methanol or ethanol, preferably methanol. In another non-limiting embodiment, the alkali is selected from a group comprising sodium hydroxide or potassium hydroxide, preferably sodium hydroxide. The temperature range for the TE reaction is at temperature ranging from about 60°C to about 90°C, preferably about 70°C to about 85°C, preferably at about 72°C to about 83°C, preferably at about 73 °C to about 82°C, more preferably at about 74°C to about 78°C and most preferably at about 76°C. The rotating speed of the vessel for agitating the oil during TE reaction after addition of the catalyst is about 500 rpm to about 1200 rpm, preferably 600 rpm to about 1100 rpm, more preferably about 700 rpm to about 1000 rpm, most preferably at about 800 rpm. The duration of trans-esterification reaction is about 30 minutes to about 90 minutes, preferably about 60 minutes. In an embodiment of the present disclosure, the average yield of CME and glycerol at a ratio of about 9: 1 is obtained by the trans-esterifcation. The partial purification of the crude glycerol fraction shows an average yield of about 70 to 80% glycerol.

In an embodiment of the present disclosure, the yield of CME is about 90%, i.e., about 900 mL of CME is obtained from about 1L of coconut oil.

In an embodiment of the present disclosure, coconut oil, preferably fresh coconut oil, is extracted from dried copra by expeller method. Coconut oil has negligible level of unsaturation and presence of short chain fatty acids. For the present study, free fatty acid content of the fresh oil is checked and is found to be less than about 1%. Moisture level of the oil is checked and found to be less than about 3%. The quality of the coconut oil is ensured by determining the parameters like moisture, lipid composition, fatty acid profile, iodine value, saponification value and peroxide value following the standard methods of American Oil Chemists' Society (AOCS) and International Union of Pure and Applied Chemistry (IUPAC).

In another embodiment of the present disclosure, mature coconuts (about 11-12 months of age) are harvested from healthy palms and fresh endosperm is separated from them. The endosperm is dried in oven for removing moisture to a level of about 2-3% and the oil is extracted by using expeller machine. The free fatty acid content of the oil is determined by titrimetric method.

In evaluation of complete procedure employed in the process, the oil extraction part is also significant. Regulation of low moisture and low free fatty acid content in the oil are essential factors for efficient trans-esterification. Moisture level of the oil is minimized by oven drying of the endosperm and the free fatty acid formation in the oil is also regulated by hygienic endosperm processing by oven drying. The extraction of oil by expeller machine maintains quality of the oil.

In an embodiment, the coconut methyl ester is prepared by trans-esterification process, provided below:

Fresh coconut oil with about 0.5% to about 1% free fatty acid (FFA) and > about 1% moisture, preferably about 1-3% moisture is heated at about 100°C for about 20 minutes with continuous stirring for removing the traces of moisture. The pre heated oil is cooled at about 80°C and stirred at a slow speed, prior to the addition of the alcohol-catalyst mixture. As part of the trans-esterification reaction, concentration of alcohol is standardized to a range of about 10% to about 20%, preferably at about 15%. Concentration of the sodium hydroxide catalyst is standardized to a range of about 0.5% to about 1.5%, preferably about 1%. A mixture of alcohol and alkali is prepared by mild stirring till the alkali completely dissolves in the alcohol. The alcohol-alkali mix is added to the preheated oil slowly with constant agitation and the temperature is maintained at about 80°C -90°C and the agitation is continued vigorously for about 70-90 minutes. After completion of the trans-esterification, the oil is cooled at room temperature (i.e. at about 30°C) and kept for about 8-10 hours. After settling, the upper ester layer is decanted by a separating funnel and the lower glycerol layer is removed and stored separately. The ester layer is washed with hot water about four to five times for removing impurities and traces of alkali (the absence of alkali is be determined by phenolphthalein test). The upper ester layer is separated carefully and vacuum heated for removing moisture. Final ester obtained is transparent having a light yellow colour and is named as coconut methyl ester (CME). A flow diagram to illustrate the above method is provided in Figure 1.

In an embodiment of the present disclosure, the CME is quantified by employing a graduated measuring jar.

In an embodiment of the present disclosure, the glycerol is quantified by employing a graduated measuring jar.

In an embodiment of the present disclosure, CME is used as an effective biofuel as well as a substitute for diesel. The physical and chemical features of the CME obtained by the present disclosure, is based on mode of its preparation and treatment.

The prepared CME is subjected to quality analysis for determining its functionality. Parameters such as Cetane number, Cetane index, pH, flash point, viscosity, acidity, ash, carbon residue, cold filter plugging point, copper strip corrosion, density, lubricity, oxidation stability, pour point, contamination, total sulphur, water content, etc. are analyzed. The parameters are measured using standard protocol known in the art for measuring the functional property of biofuel. The data obtained is compared with the Bureau of Indian Standards (BIS) for biodiesel, presented in Table 1 below. The test values of all the parameters of the CME obtained are found to be at par with the biodiesel standard indicating that CME is useful as a biofuel for diesel engine, as an alternate to use of diesel. Table 1; Physicochemical properties as per biodiesel standard

The physicochemical properties of coconut methyl ester (CME) as per the requirements of fuel quality, strongly support functional ability of CME as a biofuel. The supporting factors like cetane number (42), kinematic viscosity (3.65), flash point and cloud point remain distinct for CME from that of other methyl esters derived from vegetable oils.

In an embodiment of the disclosure, the CME biofuel obtained is used in a diesel engine and combustion ignition engine (CIE) without any technical modification of the engine.

The CME of the present disclosure is an ecofriendly biofuel and has all the physico-chemical properties of biofuel. As a practical test, CME is used as a fuel in a diesel engine. At first stroke itself the engine shows its function and works continuously without any unusual sound or missings.

Additional embodiments and features of the present disclosure will be apparent to one of ordinary skill in art based upon description provided herein. The embodiments herein provide various features and advantageous details thereof in the description. Descriptions of well- known/conventional methods and techniques are omitted so as to not unnecessarily obscure the embodiments herein. Further, the disclosure herein provides for examples illustrating the above described embodiments, and in order to illustrate the embodiments of the present disclosure certain aspects have been employed. The examples used herein for such illustration are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the following examples should not be construed as limiting the scope of the embodiments herein.

EXAMPLES;

Example 1;

Coconut Methyl Ester and glycerol is obtained by the steps of preparation of fresh coconut oil with low Free fatty acids (FFA), followed by trans-esterification of the coconut oil which includes pre-treatment of oil, preparation of methoxide and trans-esterification reaction. This is thereafter subjected to the separation of the ester fraction, vacuum heating and quantification of the coconut methyl ester and the glycerol. Example 1.1; Preparation of fresh coconut oil with low Free fatty acids (FFA)

Mature coconuts (about 11-12 months age) are harvested from healthy palms and fresh endosperm is separated from them by breaking the shell and scooping the endosperm. The endosperm is grated in a hammer mill and oven dried in a cabinet flow drier at about 60°C for about 2 hours for removing the moisture to a level of about 2-3 %. The oil is extracted by using expeller machine. The schematic representation of the protocol used to produce oil is illustrated in figure 2. The free fatty acid content of the oil is determined by titrimetric method (standard method as per AOCS and IUPAC). Example 1.2; Trans-esterification of Coconut oil

Examplel.2.1; Pretreatment of oil

The fresh oil is heated at about 100°C for about 20-30 minutes for removing the excess moisture. Example 1.2.2; Preparation of methoxide - the catalyst for esterification

The catalyst for the trans-esterification process, i.e. the methoxide is prepared at three different concentrations of methanol i.e. about 10%, about 15% and about 20% with respect to the volume of the oil. Methanol is purchased from a licensed agency and distilled for preparation of methoxide. About 1% NaOH is added to the methanol by continuous shaking for about 20 minutes till NaOH dissolves in methanol completely in the alcohol mixture.

Example 1.2.3; Trans - esterification reaction

The methoxide is added slowly to the preheated (about 80-90°C) oil to obtain reaction mixture with mild agitation. The agitation speed is increased to about 700 rpm to about 1000 rpm, preferably about 800 rpm after addition of the methoxide and the total mixture is refluxed for about 70-80 minutes, preferably about 75 minutes, at about 70°C-90°C, preferably about 76°C. After the esterification process, i.e. the completion of methyl ester formation, the heating is stopped and the mixture is cooled at room temperature insitu for about 8-10 hour, preferably about 9 hour. Example 1.3; Separation of the ester fraction

Methyl ester is obtained by purification of the two fractions. Clear upper layer of methyl ester is slowly transferred to the separating funnel for further purification. Lower layer of glycerol is removed and stored separately. The crude methyl ester in the separating funnel is thoroughly washed with hot water (about 90°C) for removing the residual catalysts and other impurities. The aqueous wash is continued for about 5-6 times till the drained aqueous phase is free from NaOH.

Example 1.4; Vacuum Heating

At the end of the production process, the purified coconut methyl ester is subjected to vacuum heating at a temperature of about 100°C for ultimate removal of traces of water molecule from the ester. The final product is analyzed for revealing physicochemical properties and ignition quality of ester for detecting its functional ability as biofuel. The physicochemical properties of the CME obtained as against BIS specifications of biodiesel are analyzed at quality control department, Kochi Refinery, Bharat Petroleum Corporation Limited, Cochin.

Example 1.5; Quantification of the coconut methyl ester

The purified ester is quantified and the volume is estimated employing a graduated measuring jar per litre oil. Yield of about 10 batches of the experiment is given below in table 2.

From fifty trials of esterification reaction conducted, yield of ester and glycerol is consistently observed in a ratio of about 9: 1, i.e. one litre of coconut oil yielded about 900 ml of ester and about 100 ml of glycerol.

Table 2; Yield of CME and glycerol obtained per litre of coconut oil in different batches of transesterifcation with constant temperature of about 76°C and at a concentration of methoxide at about 15% and NaOH at about 1%

Batch No. Temperature (°C) CME (ml) Glycerol (ml)

Batch-I 76 886±0.05 122±0.012 Batch-II 76 910±0.0316 115±0.022

Batch-Ill 76 880±0.04 118±0.012

Batch- IV 76 910±0.0332 118.4±0.009

Batch-V 76 904±0.068 109.8±0.026

Batch- VI 76 898±0.08 117.4±0.022

Batch- VII 76 904±0.068 110±0.030

Batch-Vm 76 894±0.051 115±0.025

Batch- IX 76 908±0.038 110±0.035

Batch-X 76 906±0.51 114.4±0.032

AVG 900 ml 115 ml

Example 2;

Example 2.1; Extraction of coconut oil

Matured coconuts (about 11- 12 months) are harvested from healthy coconut palms and dehusked. The dehusked nuts are broken into two halves and dried in a hot air oven for about 8 hours for deshelling. Initially the temperature of the hot air oven is kept at about 90°C for about 3 hours for the fast recovery of moisture and subsequently the temperature is reduced to about 70°C for avoiding the browning of the endosperm. After proper drying, the deshelled dry endosperm (copra) is fed into an expeller machine for the extraction of the oil. The coconut oil is thus extracted from dried copra processed from fresh mature nuts by effective expeller extraction procedure and an average yield of 68-70% is obtained at each trial.

The quality of the coconut oil is ensured by determining the parameters like moisture, lipid composition, fatty acid profile, iodine value, saponification value, and peroxide value following the standard methods of American Oil Chemists' Society (AOCS) and International Union of Pure and Applied Chemistry (IUPAC). Table 3 demonstrates the physicochemical properties of the extracted coconut oil. Table 3; Physicochemical properties of coconut oil

The trace amount of free fatty acid (FFA- about 0.1%) and the moisture (about 0.05%) content shows the stability of the oil for storage. The saponification value of about 250 and iodine value of about 8 of the oil indicate the presence of higher level of saturated lipids. The lipid composition of extracted oil exhibits a profile of about 95.6% -tri acyl glycerides, about 0.57 % -di acyl glycerides, about 3.4%- polar acyl glycerides, about 0.04% phospholipids, about 0.02% glycolipids and traces of mono acyl glycerides. The fatty acid profile of coconut oil exhibits the content of short and long chain fatty acids with about 93% saturated lipids and the remaining unsaturated .The distribution of short chain fatty acids of Laurie (about 47.2 %), Myristic (about 19.42 %), Caprylic (about 8.21 %) and Capric (about 5.59 %) acids indicate the uniqueness of the coconut oil compared with other vegetable oils (Table 4).

Table 4; Fatty acid composition of the coconut oil

Fatty acid Name Composition (%)

Caproic acid (C6:0) 0.37

Capry c acid (C8:0) 8.21 Capnc acid (CI 0:0) 5.59

Laurie Acid (CI 2:0) 47.08

Myristic acid (CI 4:0) 19.42

Palmitic acid (CI 6:0) 7.80

Stearic acid (CI 8:0) 4.29

Oleic acid (C18: l) 4.30

Linoleic acid (CI 8:2) 1.81

Arachidic acid (C20:0) 1.03

Example 2.2; Production of Coconut methyl ester

Example 2.2.1; Preheating of the oil

A known volume of fresh coconut oil (about 1L) with less than about 0.1% FFA is heated separately at about 90°C for about 20 minutes for removing the traces of moisture.

Example 2.2.2; Preparation of the catalyst

The catalyst used for the reaction is sodium methoxide. For standardizing the concentration of methanol and sodium hydroxide, several trials are done using a range of about 5-25% methanol and about 0.5-1.5 % NaOH. The methanol- alkali mixture is blended by continuous gentle agitation at about 700 rpm for about 20 minutes. The alcohol- alkaline solution is prepared freshly in order to maintain the catalytic activity and to prevent the moisture absorbance.

Example 2.2.3; Transesterifcation reaction

The freshly prepared methoxide solution is slowly charged to the preheated oil and the reaction vessel is connected with water condenser for avoiding evaporation of methanol. The temperature of the reaction is at temperature ranging from about 70°C to about 85°C. The reaction is performed for about 1 hour with continuous agitation for the completion of coconut methyl ester (CME) production. The trans-esterification reaction of the oil iscarried out by doing more than about 50 trials with a capacity of about one litre for optimizing the methoxide composition, temperature of the reaction and the yield of CME and glycerol. For the reaction, about 15% methanol with about 1% sodium hydroxide is found to provide maximum catalytic effect (Figures 3a & 3b). Temperature range for the reaction is optimized by performing the reactions at varied temperature ranging from about 70-85°C. The temperature of about 76°C is found to provide maximum yield of CME (Figure 4).

Example 2.2.4; Settling and Separation

After completion of the reaction, the reaction mixture is allowed a settling time of about 8-10 hours in a separating funnel. Two layers are obtained with a top layer of Coconut Methyl Ester (CME) and the bottom layer of sodium salt of glycerol with other organics. The crude glycerol layer obtained is decanted out and used for the separation of glycerin while the top CME layer is used for further purification

Example 2.3; Purification of CME

The recovered coconut methyl ester layer contains traces of the catalyst NaOH and methanol. For removing the alkali, the CME layer is washed gently with hot water. The process is repeated for about 6 - 7 times, till it becomes neutral. The neutral CME is distilled under vacuum for removing the traces of methanol and water present in the ester. No difference is observed in the amount of purified CME obtained after the recovery of methanol and moisture by separation and distillation processing.

Example 2.4; Partial purification of Glycerol

The pH of the collected glycerol layer from the reaction is reduced to about 5-6 by the addition of phosphoric acid. After acidification, the mixture is incubated at room temperature for settling for about 12 hours. After settling, two layers appear, a bottom layer comprising inorganic salts & glycerol and a top layer comprising impurities. For the partial purification of glycerol, the bottom layer is neutralized with about 5M NaOH and the inorganic salt present in the layer is precipitated by the addition of methanol. The precipitate is filtered out and the filtrate that contains glycerol is distilled for the removal of solvent residues. The amount of glycerol is determined by standard colorimetric method. The partial purification of the crude glycerol fraction shows an average yield of about 70 to 80% glycerol.

An average yield of about 900 ml CME and about 115 ml glycerol is recovered from about one litre of coconut oil by transesterifcation.

Example 3; Biofuel quality of CME

In order to ascertain the characteristic features of CME as a biofuel, the physico chemical properties of CME is analyzed against BIS specifications for biodiesel at quality control department, Kochi Refinery, Bharat Petroleum Corporation Limited, Cochin. The main criterion of biofuel quality is the inclusion of its physical and chemical properties into the requirements of the adequate standard. Though the current standards for regulating the quality of biofuels vary from region to region, their similarity with the existing diesel fuel standards common in the regions is crucial in determining the fuel quality. Table 5 illustrates the test values of CME showing the physicochemical properties against biodiesel standards.

Table 5; Physicochemical properties of instant Coconut methyl ester against biodiesel

3Hours @100°C

9 Density @ 15°C About 884.3 kg/m³ 860-900 kg/m3

10 Flash point (Abel/PMC) About 96°C 93-120°C

Kinematic Viscosity @ 3.5 - 5.0 cST

11 About 3.65 cST

40°C

Lubricity, corrected

12 wear scar diameter About 151 Microns 150-155 microns (WSD) @ 60°C

13 Oxidation Stability About 14 g/m³ 12-16 g/m³

14 Pour Point About -3 °C -3 - 0°C

15 Total contamination About 13 mg/Kg 24 mg/kg

16 Total sulphur Nil 0.001-0.05%

17 Water Content About 500mg/Kg 500 mg/kg

The physicochemical properties of coconut methyl ester (CME) as per the requirements of fuel quality strongly support functional ability of CME as a biofuel. The supporting factors like cetane number (42), kinematic viscosity (3.65), flash point and cloud point remain distinct for CME from that of other methyl esters derived from vegetable oils.

The test values strongly support the functional similarity of CME with that of diesel as per the requirement of fuel quality. Cetane number (CN) of CME is observed as 42.1. As the primary indicator of ignition quality of fuels, the optimal range of the CN is identified in between 41-56 based on the global biodiesel standards. The cetane number of a biofuel depends on the chemical structure of the vegetable oil, the degree of unsaturation, number of carbon atoms and the nature of alcohol used for esterification of the oil. The cetane number of about 42 obtained for the CME of the present disclosure supports the recommended value. Density of CME is found very close to that of biodiesel. Since density is strongly influenced by temperature, the quality standards state the density of fuels at 15°C. As an effective parameter of fuel quality, the density directly affects the fuel performance, quality of atomization and combustion. More over the similarity noticed in the density of the CME with biodiesel standard indicates the purity of the fuel without any contaminants. Viscosity is a crucial factor of liquid fuels that highly influences ease of starting the engine, spray quality, size of the particles, penetration of the injected jet, quality of the fuel-air mixture and combustion. The similarity observed in the viscosity of the CME of the present disclosure with diesel strongly indicates the smooth operational power of the fuel.

As one of the main criteria of fuel quality, the pour point (PP) and cold filter plugging point (CFPP) property of the CME is found supportive to biodiesel as per the standards. Since the PP and CFPP values represent the cloud flow performance of the fuel in compression ignition engine, their values for the CME supports its efficiency as biofuel in cold environment. The similarity observed in the flash point of CME (about 96°C) and recommended range for biodiesel (93°C to 120°C) indicate the ability of ignition. Moreover, it makes the fuel comfortable during storage, transportation and handling. . The values of lubricity, oxidation stability, water content and acid value of CME showcompetent nature of the CME with biodiesel standards and the values support its excellence as a good biofuel. The low carbon residue, minimal acidity and the absence of sulphur elements add more positivity to the quality of the CME. Example 4; Functional tests of CME as biofuel

Based on its physicochemical features, the CME is used as fuel in a diesel engine test rig of matador vehicle (Trade mark of FORCE MOTORS) without any modification to the engine system or fuel lines. The functional property of the CME is evaluated in a diesel vehicle (TATA Ace -Magic- Trade mark of TATA MOTORS) and the torque and power of the diesel vehicle using CME is checked on a Dynamometer. The torque (Nm) and power (bhp) of the vehicle using CME are determined and compared with the specifications stipulated by the manufacturer.

Based on its physicochemical features, the CME is used as fuel in a diesel engine test rig of matador vehicle without any modification to the engine system or fuel lines. The engine starts and achieves maximum rpm and is stable across various acceleratory inputs without any unusual sound or missing. The functional test of the CME provides a positive sign for using CME as a fuel for road trials in a new diesel vehicle (Figures 5a and 5b). The power and torque of the vehicle using diesel as fuel are recorded at about 16 bhpat 3200 rpm and at about 38 Nm at 2000 rpm.

The successful part of any prospective biofuel is, whether an engine using the biofuel performs similarly or better than an engine using normal gasoline based diesel. With respect to the similarity noticed in the functional feature of CME as a biofuel, the CME is used in a diesel engine of a new vehicle (TATA Ace Magic-diesel) for determining its technical feasibility. The torque and the power of the engine are determined using CME as a fuel in the new vehicle. It is reported that, performance of any fuel is judged by power and torque output that it generates. The test run is done on TATA Ace Magic-diesel vehicle on dynamometer for determining the power and torque as against the specifications of the manufacturer of the vehicle (Table 6). The power and the torque of the CME as a fuel are found similar to the values as per the specifications.

Table 6; Technical specifications of the diesel vehicle stipulated by the manufacturer

Figures 5a & 5b indicate the power and torque of CME as a biofuel. Under the dynamometer test, the CME provides a power of about 16 bhp at about 3000 rpm and a torque of about 38.5 Nm at about 2000 rpm as against manufacturer specification of 16 bhp at 3200 rpm and 38 Nm torque at 2000 rpm (Table 6). Thus, the study clearly indicates that there is no overall marked difference in the performance of the coconut methyl ester as biofuel in a diesel engine.

Besides the similarity noticed in the power and torque of the engine between the CME and diesel showing the fuel energy, the mileage of the vehicle showed a significant increase of about 22.5 km/1 from the 16 km/1 recommended for diesel by the manufacturer, which in turn confirms the thermal efficiency of the CME. Even though the overall fuel efficiency may vary from vehicle to vehicle, the higher mileage of CME than diesel supports the thermal efficiency of the CME during the performance of the vehicle. Moreover K value obtained for CME by diesel opacity test for detecting the level of air pollution clearly indicates the poor emission of smoke confirming the usability of the CME as an ecofriendly fuel (Table 7).

Table 7; Computerized pollution under control certificate using CME as fuel

The present disclosure demonstrates a new trend in the field of renewable energy source and in the area of biofuel production. The significant increase noticed in the mileage of CME with that of diesel stands as a monetary advantage supporting the CME production at industrial level. Precisely, the important technical advantages of the CME of the present disclosure as fuel in diesel engines are as follows:

(i) CME can be used straight away as fuel in diesel engines. The prerequisites of using CME in diesel engine only includes thorough cleaning of the fuel system including fuel lines and installation of fresh fuel filters.

(ii) No modification is required in the engine components,

(iii) No modification is required in the fuel lines. (iv) CME need not be blended with any other fuel for use in diesel engines.

(v) No additives are required for the CME to work in a diesel engine.

(vi) All vital engine parameters like temperature, oil pressure, fuel consumption, power and torque are within the limits or better than the specification of the vehicle manufacturer.

Additional embodiments and features of the present disclosure will be apparent to one of ordinary skill in art based on the description provided herein. The embodiments herein provide various features and advantageous details thereof in the description. Descriptions of well-known/conventional methods and techniques are omitted so as to not unnecessarily obscure the embodiments herein.

The foregoing description of the specific embodiments fully reveals the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments in this disclosure have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

Throughout this specification, the word "comprise", or variations such as "comprises" or "comprising" wherever used, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity. The use of the expression "at least" or "at least one" suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results. Any discussion of documents, acts, materials, devices, articles and the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.

While considerable emphasis has been placed herein on the particular features of this disclosure, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other modifications in the nature of the disclosure or the preferred embodiments will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.

Claims

We Claim;

1) A process for obtaining ester optionally along with glycerol, said process comprising acts of: a) obtaining endosperm from plant source and extracting oil from the endosperm;

5 b) pretreating the oil and adding catalyst to the pre-treated oil to obtain reaction mixture; c) treating the reaction mixture to obtain ester fraction and glycerol fraction, wherein the glycerol fraction is heavier than the ester fraction;

10 e) optionally obtaining and optionally quantifying glycerol from the glycerol fraction.

2) The process as claimed in claim 1, wherein the plant source is selected from group comprising Cocos nucifera, preferably coconut.

153) The process as claimed in claim 1, wherein the endosperm is obtained by separating it from the plant source, optionally grating and drying the endosperm; and wherein the drying of the endosperm is at temperature ranging from about 50°C to about 100°C, preferably about 60°C to about 90°C, for time duration ranging from about 30 minutes to about90 minutes, preferably about 60 minutes.

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4) The process as claimed in claim 1, wherein the oil has free fatty acid content ranging from about 0.1% to about 1.5%, preferably about 1% and moisture content ranging from about 1% to about 3%, preferably about 1%; wherein the extracting of oil is carried out in expeller machine; and wherein the pretreating of the oil is carried out at temperature ranging from

25 about 85°C to about 95°C, preferably about 90°C for time duration ranging from about 20 minutes to about 30 minutes.

5) The process as claimed in claim 1, wherein the treating comprises acts of:

a) agitating the reaction mixture at about 700 rpm to about 1000 rpm, preferably about 30 800 rpm after addition of the catalyst for time duration ranging from about 30 minutes to about 90 minutes, preferably about 50 minutes; b) refluxing the mixture for time duration ranging from about 60 minutes to about 80 minutes, preferably about 75 minutes, at temperature ranging from about 60°C to about 90°C, preferably about 76°C; and

c) cooling at temperature ranging from about 25°C to about 35°C, preferably about 30°C 5 for time duration ranging from about 8 hours to about 10 hours, preferably about 9 hours to obtain the ester fraction and the glycerol fraction.

6) The process as claimed in claim 1 , wherein the catalyst is alcohol-alkali catalyst, wherein the alcohol is selected from group comprising methanol, ethanol or any combinations thereof, 10 preferably methanol at amount ranging from about 10 v/v% to about 20 v/v %, preferably about 15 v/v %; and the alkali is selected from group comprising sodium hydroxide, potassium hydroxide or any combinations thereof, preferably sodium hydroxide at amount ranging from about 0.5 w/v % to about 1.5 w/v %, preferably about 1 w/v %.

157) The process as claimed in claim 1, wherein the catalyst is alkoxide such as methoxide, preferably sodium methoxide; and wherein the catalyst is optionally freshly prepared catalyst.

8) The process as claimed in claim 1, wherein yield of the ester and the glycerol is at ratio of 20 about 8:2 to about 9: 1 , preferably about 9: 1.

9) The process as claimed in claim 1, wherein the separating is carried out by incubating for time duration ranging from about 6 hours to about 12 hours, preferably for about 8 hours to about 10 hours.

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10) The process as claimed in claim 1, wherein the ester is methyl ester; and wherein the ester is obtained by subjecting the ester fraction to acts comprising washing, vacuum heating at temperature ranging from about 80°C to about 120°C, preferably about 100°C or any combination thereof.

30 11) The process as claimed in claim 1, wherein the glycerol is obtained from the glycerol fraction by subjecting to pH ranging from about 4 to about 7, preferably to pH of about 5 to about 6, and precipitation.

512) Methyl ester obtained from the process as claimed in claim 1.

13) Use of methyl ester obtained by the process as claimed in claim 1 as a biofuel.

14) The process as claimed in claim 1 or the Methyl Ester as claimed in claim 12, wherein the0 ester is used as biofuel.

15) The process as claimed in claim 1 or the Methyl Ester as claimed in claim 12 or the use as claimed in claim 13, wherein said biofuel is used as automotive fuel. 5