Title of Invention	"A PROCESS FOR THE PREPARATION OF LIQUID LUBRICANTS FROM NON-EDIBLE VEGETABLE OILS"
Abstract	Liquid lubricants are prepared from non-edible vegetable oils by modifying castor oil by acetylation, hydrogenation and transesterificaiton or combinations thereof. According to the invention castor oil is degummed by dissolving it in isopropanol at 10-15°C, the degummed castor oil is hydrogenated in presence of a catalyst and hydrocarbon solvent at 35-200°C and 1-20 bar pressure. Modification of castor oil by acetylation is carried out by reacting oil or hydrogenated oil with acetic anhydride at 40-120°C. The transesterification is done by reacting the degummed oil with a monohydric alcohol having 5-10 carbon atoms in presence of a catalyst preferably a basic catalyst. The lubricant is purified by treatment with fuller earths.

Title of Invention

"A PROCESS FOR THE PREPARATION OF LIQUID LUBRICANTS FROM NON-EDIBLE VEGETABLE OILS"

Abstract

Liquid lubricants are prepared from non-edible vegetable oils by modifying castor oil by acetylation, hydrogenation and transesterificaiton or combinations thereof. According to the invention castor oil is degummed by dissolving it in isopropanol at 10-15°C, the degummed castor oil is hydrogenated in presence of a catalyst and hydrocarbon solvent at 35-200°C and 1-20 bar pressure. Modification of castor oil by acetylation is carried out by reacting oil or hydrogenated oil with acetic anhydride at 40-120°C. The transesterification is done by reacting the degummed oil with a monohydric alcohol having 5-10 carbon atoms in presence of a catalyst preferably a basic catalyst. The lubricant is purified by treatment with fuller earths.

Full Text	The present invention relates to a process for the preparation of liquid lubricants from non-edible vegetable oils. More specifically, this invention relates to the modification of castor oil by acetylation, hydrogenation and tranesterification or combinations thereof to prepare liquid lubricant base oil with acceptable biodegradability, suitable for application in industrial, automotive and as general purpose lubricant formulations. Traditionally, the petroleum-derived mineral oils have been the basic sources of industrial and automotive lubricants. The petroleum base lubricating oils are hydrocarbons consisting of naphthenes, paraffins and aromatics. Various additives, which are primarily chemicals of defined composition or structure are added to the mineral base oils to improve the physic-chemical properties and performance for specific applications. Mineral oil based lubricants, generally suffer from many disadvantages such as high toxicity to the environment, poor biodegradability. The other types of lubricants known as synthetic lubricants, are designed for use in extreme conditions of temperature, pressure, radiation or chemical and have excellent lubricity and thermal stability. The synthetic lubricants are relatively costly. Polyglycols, polybutenes, dibasic acid esters, fluoropolymers, polyol esters, phosphate esters, silicones, polyalpha olefins etc. are commonly used synthetic lubricants for various applications. Synthetics are also toxic to environment and are not readily biodegradable. The use of vegetable oils as lubricants is known for a long time. Vegetable oils are, by their chemical nature, long chain fatty acids triesters of glycerol and are capable of providing the desirable lubricant properties such as good boundary layer lubrication, high viscosity index, high flash point and low volatility. The major limitations of vegetable oils which restrict their use as lubricant are their thermoxidative stability and low temperature behaviour. European patent EP0714974, describes food grade lubricant composition, useful as hydraulic oil, gear oil and compressor oil for food service industry, comprising-of major amount of a genetically modified vegetable oil and minor amounts of a performance additive phosphorous compound or a non-generically modified vegetable oil. In the patents assigned to Agro Management Group Inc. (Patent No. US 5888947 PCT/US96/9509) formulation for lubricants, for use in four internal combustion engines. Comprising of a base oil such as soyabean, canola, rapeseed, crambe, safflower and sunflower, oil containing hydroxy fatty acids derived from castor, less querella etc and an oil source containing vegetable oil or animal wax. Patent WO9207051 assigned to Int. Lubricants Inc. discloses the process for preparing lubricant additives based n the telomerised vegetable oils such as rape seed, crambe, meadow foam, soya bean, peanut, corn, safflower, sunflower, cottonseed, olive, coconut, palm, linseed and combination there off. In another patent (EP05567995 assigned to Castrol Ltd. GB) satisfactory lubricants for industrial and automotive requirements based on palm oil are described. Vegetable based lubricants prepared using base oils derived from plants which are members of the genus Brassica and Cruciferea (mustard) family, e.g. rapeseed, crambe and canola are described in another patent (WO 96/39476). In view of the growing concern about the environment, there is a need for biodegradable, non-toxic lubricants for automotive and industrial applications, which are derived from renewable resources. The lubricant should be readily biodegradable, preferably by microbes naturally present in the environment and be cost effective. In the prior art for producing lubricants from vegetable oil vegetable oils used are edible oils or genetically modified vegetable oils. The oils generally used include soya bean, canola, rape seed, crambe, safflower, sunflower, castor, animal wax, jojoba oil etc. The focus have been on the use of such vegetable oil based lubricants as additives in petroleum based lubricants to enhance lubricity. Unlike the lubricants of the prior art, the vegetable based lubricant base oils of the present invention are derived from renewable resources are non-toxic and readily biodegradable by natural micro organisms. The lubricant base oils of the present invention has applicability in formulations suitable as lubricants in a variety of applications including two-stroke engine oil, hydraulic oil, refrigeration oil, metal working lubricant, industrial gear oil as well as general purpose lubricants. The main object of the present invention is to provide a process for the preparation of liquid lubricants from non-edible vegetable oils which obviates the drawbacks as detailed above. Another object of the present process is to provide a process for the preparation of vegetable oil based non-toxic and biodegradable lubricant base oil. Still another object of the present invention is to provide a non-edible vegetable oil based lubricant base oil for use in metal working operations, compressor lubricants, hydraulic fluids, transformer oil, greases and internal combustion engines. Yet another object of the present invention to provide lubricant base oil form modified castor oil that exhibit improved lubrication, viscosity index, thermal stability and pour point. Yet another object of the present invention is to provide the method preparation of vegetable oil derivatives suitable for use as lubricants base stock. The present invention relates to the modification of unsaturated vegetable oils to prepare liquid products suitable for use as lubricant base stocks. More particularly the present invention is concerned with modification of castor oil to enhance the lubricant characteristics e.g. viscosity index, low temperature behaviour - pour point and oxidation stability. In a broader sense the invention may be utilized to produce vegetable oil based lubricants which possesses excellent lubricating properties and are environment friendly and biodegradable. Vegetable oils which are long chain fatty acid trimesters of glycerol (triacyl glycerols) possesses most of the desirable lubricant properties such as high viscosity index, high flash point, low volatility and good boundary lubrication. The major limitations of vegetable oils when applied to their lubricant behaviour include poor oxidative stability, low temperature behavior and compatibility with additives. Oxidation of vegetable oils is one of the major concerns that limits the use of vegetable oils as lubricant. Oxidation leads to deterioration of oil due to polymerization and degradation of oil. Polymerisation increases the molecular weight leading to increase in viscosity, gelling and loss of functionality which reduces the lubrication characteristics of the vegetable oil. Vegetable oil such as castor oil exhibits good characteristics as lubricant and provides good boundary lubrication and is biodegradable. Due to unsaturation and low solubility in mineral oil it has poor oxidation stability, poor compatibility with mineral oils based lubricants and low viscosity index. Typical characteristics of castor oil are : Viscosity, 40°C (cSt) : 252.0 Viscosity, 100°C (cSt) : 90 Viscosity Index : 90 Pour point : -10°C Acid number : 4.0 mg KOH/g During the course of research work it was found that acetylation of castor oil improves the lubrication properties of castor oil in terms of viscosity and viscosity index, low temperature behaviour i.e. pour point and oxidation stability. Viscosity index and oxidation stability can be further improved by acetylating the hydrogenated castor oil than neat castor oil. Alternatively, the lubrication characteristics of castor oil can be improved by hydrogenating and transesterifying the hydrogenated castor oil. The hydrogenated castor oil esters of C5-C7 monohydric alcohols such as 2-ethyl hexanol, 2,6 dimethyl heptanol and 2-pentyl alcohol showed marked improvement in viscosity temperature behaviour, thermal stability and low temperature behaviour; almost 100% improvement in viscosity index could be obtained in case of 2-ethyyl hexyl ester of hydrogenated castor oil. Treatment with fullers earth provides a lubricant with improved colour and lower acidity. Accordingly the present invention provides a process for the preparation of liquid lubricants from non-edible vegetable oils which comprises degumming and purification of vegetable oil by dissolving the oil in isopropanol in the ratio of 1-5 wt./wt followed by cooling to 10-15°C for 2-6 hour, filtering the mixture and removing the solvent, modifying the purified vegetable oil by acetylation, transesterification and hydrogenation or combinations thereof, wherein the acetylation is carried by reacting the vegetable oil or hydrogenated vegetable with acetic anhydride at temperature in the range of 40-120°C, transesterification is accomplished by reacting with a monohydric alcohol having 5-10 carbon atoms, hydrogenation is carried out in presence of a catalyst and hydrocarbon solvent having 5-8 carbon atoms preferable n-hexane or heptane at 35-200°C at 1-30 bar pressure, and purifying the lubricant by treatment with fullers earth. In an embodiment of the present invention the vegetable oil is preferably castor oil. In another embodiment of the present invention the transesterification of the vegetable oil is done with a monohydric alcohol having 5-10 carbon atoms. In yet another embodiment of the present invention the hydrogenation step is carried out in presence of a catalyst to obtain the hydrogenated oil having iodine value of less than 70. In still another embodiment of the present invention the degumming and purification of vegetable oil is accomplished by dissolving the oil in isopropanol in the ratio of 1-5 wt/wt followed by cooling to 10-15°C, filtering the mixture and removing the solvent by distillation. In still another embodiment of the present invention the hydrogenation is carried out in pressure of a catalyst and a hydrocarbon solvent having 5-8 carbon atoms preferably n-hexane or n-heptane at a temperature preferably in the range of 45-180°C at a pressure preferably at 3-26 bar. In still another embodiment of the present invention the acetylation is carried out by reacting the vegetable oil or hydrogenated vegetable oil with acetic anhydride at a temperature preferably in the range of 40-120°C. In still another embodiment of the present invention the purification of the lubricant base oil is obtained by treating with fullers earths. In still another embodiment of the present invention lubricant prepared is useful for lubricant formulations for application in automotive lubricants, gear oil, cutting oil, turbine oil, hydraulic oil, greases and metal forming oil as well as general purpose lubricant. It will be apparent from the foregoing that the present invention provides biodegradable base oils prepared form modified vegetable oil, particularly castor, useful for preparing lubricant formulations for automotive, and industrial applications. The lubricant base oils prepared according to the present invention exhibit improved lubrication properties over the neat castor oil in terms of improved viscosity index, pour point and oxidation stability and have excellent biodegradability and non-toxic. The invention is described by the following example, which are given only for the purpose of illustration and are not intended to limit the scope of the invention. Example-1 466 gm of castor oil was taken in jacketed stirred reactor and heated slowly to 40-50°C. To this 153 g of acetic anhydride was added drop wise over a period of one hour. The temperature was slowly raised to 120°C and maintained for 3 h with constant stirring. The liquid thus obtained is distilled to remove acetic acid and the product left behind was washed with hot water to remove traces of acid to pH 6-7. The liquid after washing is dissolved in toluene and refluxed in Dean Stark trap to remove water. The toluene is distilled off. Last traces of toluene were removed by distillation under vacuum (-20-50 mm Hg). The dried product (acetylated castor oil) is treated with fullers earth to remove any acidity and colouring materials to obtain a straw coloured acetylated castor oil. The acetylated castor oil thus obtained had the following characteristics: Viscosity, 40°C (cSt) : 17.6 Viscosity, 100oC (cSt) : 15.70 Viscosity Index : 142 Pour Point, °C : Iodine value : 64 AcidNo.mgKOH/g : Oxidation stability at 95°C, 120 h: Viscosity at 100°C (cSt) before and after test was 15.75 and 14.67 respectively. Example - 2 Procedure of example-1 was repeated except that in place of castor oil, hydrogenated castor oil was taken and the reaction temperature was kept at 80-85°C. The liquid product thus obtained (acetylated hydrogenated castor oil) had the following lubricant characteristics. Viscosity, 40°C (cSt) : 92.0 Viscosity, 100°C (cSt) : 13.6 Viscosity Index : 150 Pour point, °C : -25 Iodine value : Acid No., mg KOH/g : Oxidation stability at 95°C, 120 h: Viscosity at 100°C (cSt) before and after test was 13.60 and 14.13 respectively. Example - 3 Castor oil (600 g) was taken in a stirred autoclave. To this 600 g of n-heptane and 15 g of Raney Nickel were added. The contents were heated to 130°C and after 3 purges with hydrogen, the autoclave was filled with hydrogen upto 15 bar. The temperature and pressure were kept constant for 6 h. After cooling and releasing the pressure the contents of the autoclave were filtered to remove Raney Nickel, the filtered liquid was subjected to distillation to remove n-heptane. The remaining oily portion (hydrogenated castor oil) obtained after distillation had an iodine value of Ethyl hexyl alcohol (431 g) was refluxed separately with sodium metal (5g) till it dissolved to give clear solution. 520 gm of the Hydrogenated Castor oil was melted and added to 431 gm of sodium treated ethyl hexanol. The mixture was refluxed at 180-200°C for 30 hours. Part of the glycerol was recovered as a lower layer during this operation. Excess of Ethyl hexyl alcohol/ nonyl alcohol was removed by distillation under vacuum at 10 mm. pressure (120-130°C). The remaining contents were kept at 120°C and treated with steam for 1 to 2 hours. The lower layer containing glycerol and hydrolysed sodium ethyl hexanoate/ sodium nonanoate was neutralized with hydrochloric acid to pH 6-7. The contents were allowed to stand for 2 to 3 hours and the lower layer containing remaining of glycerol with drawn. The upper layer was dissolved in Toluene and water was removed by Dean and Stark trap. The dried upper layer (412 gm) was treated 110 gm of Acetic anhydride by drop wise addition at 40°C for 1 hour followed by reflux of the content with constant stirring at 110-120°C. The toluene and Acetic acid was distilled off. The remaining contents were washed with hot water to pH 6-7. The product was dried under vacuum at 70-80°C to remove traces of water. Viscosity, 40°C (cSt) : 31.10 Viscosity, 110°C (cSt) : 6.80 Viscosity Index : 187 Pour point, °C : Iodine value : Acid No., mg KOH/g : Oxidation stability at 95°C, 120 h: Viscosity at 100°C before and after test was 6.8 and 7.16 respectively. Example - 4 Procedure of example - 3 was repeated except in place of ethyl hexyl alcohol, 475 g of sodium treated nonyl alcohol (2,6 dimethyl heptanol) was taken. The lubricant characteristics of the product obtained were as follows: Viscosity, 40°C (cSt) : 48.06 Viscosity, 100°C (cSt) : 8.26 Viscosity Index : 146 Pour point, °C : Iodine value : Acid No., mg KOH/g : Example - 5 Procedure of exaple-4 was respected except in place of ethyl hexyl alcohol 2-pentyl alcohol was taken. The lubricant characteristics of the product obtained were as follows: Viscosity, 40°C (cSt) : 18.16 Viscosity, 100°C (cSt) : 4.39 Viscosity Index : 160 Pour point, °C : Iodine value : Acid No., mg KOH/g : We Claim 1. A process for the preparation of liquid lubricants from non-edible vegetable oils which comprises degumming and purification of vegetable oi! by dissolving the oil in isopropanol in the ratio of 1-5 wt./wt followed by cooling to 10-15°C for 2-6 hour, filtering the mixture and removing the solvent, modifying the purified vegetable oil by acetylation, transesterification and hydrogenation or combinations thereof, wherein the acetylation is carried by reacting the vegetable oil or hydrogenated vegetable with acetic anhydride at temperature in the range of 40-120°C,ransesterification is accomplished by reacting with a monohydric alcohol having 5-10 carbon atoms, hydrogenation is carried out in presence of a catalyst and hydrocarbon solvent having 5-8 carbon atoms preferable n-hexane or heptane at 35-200°C at 1-30 bar pressure, and purifying the lubricant by treatment with fullers earth. 2. A process as claimed in claim 1 wherein the vegetable oil is preferably castor oil. 3. A process as claimed in claims 1 and 2 wherein the transesterification of the vegetable oil is done with a monohydric alcohol having 5-10 carbon atoms. 4. A process as claimed in claims 1 to 3 wherein the hydrogenation step is carried out in presence of a catalyst to obtain the hydrogenated oil having iodine value of less than 70. 5. A process as claimed in claims 1 to 4 wherein the degumming and purification of vegetable oil is accomplished by dissolving the oil in isopropanol in the ratio of 1-5 wt/wt followed by cooling to 10-15°C, filtering the mixture and removing the solvent by distillation. 6. A process as claimed in claims 1 to 5 wherein the hydrogenation is carried out in pressure of a catalyst and a hydrocarbon solvent having 5-8 carbon atoms preferably n-hexane or n-heptane at a temperature preferably in the range of 45-180°C at a pressure preferably at 3-26 bar. 7. A process as claimed in claims 1 to 6 wherein the acetylation is carried out by reacting the vegetable oil or hydrogenated vegetable oil with acetic anhydride at a temperature preferably in the range of 40-120°C. 8. A process as claimed in claims 1 to 7 wherein the purification of the lubricant base oil is obtained by treating with fullers earths. 9. A process as claimed in claims 1 to 8 wherein lubricant prepared is useful for lubricant formulations for application in automotive lubricants, gear oil, cutting oil, turbine oil, hydraulic oil, greases and metal forming oil as well as general purpose lubricant. 10. A process for the preparation of liquid lubricants from non-edible vegetable oils substantially as herein described with references to the examples.

Full Text

The present invention relates to a process for the preparation of liquid lubricants from non-edible vegetable oils. More specifically, this invention relates to the modification of castor oil by acetylation, hydrogenation and tranesterification or combinations thereof to prepare liquid lubricant base oil with acceptable biodegradability, suitable for application in industrial, automotive and as general purpose lubricant formulations.
Traditionally, the petroleum-derived mineral oils have been the basic sources of industrial and automotive lubricants. The petroleum base lubricating oils are hydrocarbons consisting of naphthenes, paraffins and aromatics. Various additives, which are primarily chemicals of defined composition or structure are added to the mineral base oils to improve the physic-chemical properties and performance for specific applications.
Mineral oil based lubricants, generally suffer from many disadvantages such as high toxicity to the environment, poor biodegradability. The other types of lubricants known as synthetic lubricants, are designed for use in extreme conditions of temperature, pressure, radiation or chemical and have excellent lubricity and thermal stability. The synthetic lubricants are relatively costly. Polyglycols, polybutenes, dibasic acid esters, fluoropolymers, polyol esters, phosphate esters, silicones, polyalpha olefins etc. are commonly used synthetic lubricants for various applications. Synthetics are also toxic to environment and are not readily biodegradable.
The use of vegetable oils as lubricants is known for a long time. Vegetable oils are, by their chemical nature, long chain fatty acids triesters of glycerol and are capable of providing the desirable lubricant properties such as good boundary layer lubrication, high viscosity index, high flash point and low volatility. The major limitations of vegetable oils which restrict their use as lubricant are their thermoxidative stability and low temperature behaviour.
European patent EP0714974, describes food grade lubricant composition, useful as hydraulic oil, gear oil and compressor oil for food service industry, comprising-of
major amount of a genetically modified vegetable oil and minor amounts of a performance additive phosphorous compound or a non-generically modified vegetable oil.
In the patents assigned to Agro Management Group Inc. (Patent No. US 5888947 PCT/US96/9509) formulation for lubricants, for use in four internal combustion engines. Comprising of a base oil such as soyabean, canola, rapeseed, crambe, safflower and sunflower, oil containing hydroxy fatty acids derived from castor, less querella etc and an oil source containing vegetable oil or animal wax.
Patent WO9207051 assigned to Int. Lubricants Inc. discloses the process for preparing lubricant additives based n the telomerised vegetable oils such as rape seed, crambe, meadow foam, soya bean, peanut, corn, safflower, sunflower, cottonseed, olive, coconut, palm, linseed and combination there off.
In another patent (EP05567995 assigned to Castrol Ltd. GB) satisfactory lubricants for industrial and automotive requirements based on palm oil are described.
Vegetable based lubricants prepared using base oils derived from plants which are members of the genus Brassica and Cruciferea (mustard) family, e.g. rapeseed, crambe and canola are described in another patent (WO 96/39476).
In view of the growing concern about the environment, there is a need for biodegradable, non-toxic lubricants for automotive and industrial applications, which are derived from renewable resources. The lubricant should be readily biodegradable, preferably by microbes naturally present in the environment and be cost effective. In the prior art for producing lubricants from vegetable oil vegetable oils used are edible oils or genetically modified vegetable oils. The oils generally used include soya bean, canola, rape seed, crambe, safflower, sunflower, castor, animal wax, jojoba oil etc. The focus have been on the use of such vegetable oil based lubricants as additives in petroleum based lubricants to enhance lubricity.
Unlike the lubricants of the prior art, the vegetable based lubricant base oils of the present invention are derived from renewable resources are non-toxic and readily biodegradable by natural micro organisms. The lubricant base oils of the present invention has applicability in formulations suitable as lubricants in a variety of applications including two-stroke engine oil, hydraulic oil, refrigeration oil, metal working lubricant, industrial gear oil as well as general purpose lubricants.
The main object of the present invention is to provide a process for the preparation of liquid lubricants from non-edible vegetable oils which obviates the drawbacks as detailed above.
Another object of the present process is to provide a process for the preparation of vegetable oil based non-toxic and biodegradable lubricant base oil.
Still another object of the present invention is to provide a non-edible vegetable oil based lubricant base oil for use in metal working operations, compressor lubricants, hydraulic fluids, transformer oil, greases and internal combustion engines.
Yet another object of the present invention to provide lubricant base oil form modified castor oil that exhibit improved lubrication, viscosity index, thermal stability and pour point.
Yet another object of the present invention is to provide the method preparation of vegetable oil derivatives suitable for use as lubricants base stock.
The present invention relates to the modification of unsaturated vegetable oils to prepare liquid products suitable for use as lubricant base stocks. More particularly the present invention is concerned with modification of castor oil to enhance the lubricant characteristics e.g. viscosity index, low temperature behaviour - pour point and oxidation stability. In a broader sense the invention may be utilized to produce

vegetable oil based lubricants which possesses excellent lubricating properties and are environment friendly and biodegradable.
Vegetable oils which are long chain fatty acid trimesters of glycerol (triacyl glycerols) possesses most of the desirable lubricant properties such as high viscosity index, high flash point, low volatility and good boundary lubrication. The major limitations of vegetable oils when applied to their lubricant behaviour include poor oxidative stability, low temperature behavior and compatibility with additives. Oxidation of vegetable oils is one of the major concerns that limits the use of vegetable oils as lubricant. Oxidation leads to deterioration of oil due to polymerization and degradation of oil. Polymerisation increases the molecular weight leading to increase in viscosity, gelling and loss of functionality which reduces the lubrication characteristics of the vegetable oil.
Vegetable oil such as castor oil exhibits good characteristics as lubricant and provides good boundary lubrication and is biodegradable. Due to unsaturation and low solubility in mineral oil it has poor oxidation stability, poor compatibility with mineral oils based lubricants and low viscosity index. Typical characteristics of castor oil are :
Viscosity, 40°C (cSt) : 252.0
Viscosity, 100°C (cSt) : 90
Viscosity Index : 90
Pour point : -10°C
Acid number : 4.0 mg KOH/g
During the course of research work it was found that acetylation of castor oil improves the lubrication properties of castor oil in terms of viscosity and viscosity index, low temperature behaviour i.e. pour point and oxidation stability.
Viscosity index and oxidation stability can be further improved by acetylating the hydrogenated castor oil than neat castor oil.
Alternatively, the lubrication characteristics of castor oil can be improved by hydrogenating and transesterifying the hydrogenated castor oil. The hydrogenated castor oil esters of C5-C7 monohydric alcohols such as 2-ethyl hexanol, 2,6 dimethyl heptanol and 2-pentyl alcohol showed marked improvement in viscosity temperature behaviour, thermal stability and low temperature behaviour; almost 100% improvement in viscosity index could be obtained in case of 2-ethyyl hexyl ester of hydrogenated castor oil. Treatment with fullers earth provides a lubricant with improved colour and lower acidity.
Accordingly the present invention provides a process for the preparation of liquid lubricants from non-edible vegetable oils which comprises degumming and purification of vegetable oil by dissolving the oil in isopropanol in the ratio of 1-5 wt./wt followed by cooling to 10-15°C for 2-6 hour, filtering the mixture and removing the solvent, modifying the purified vegetable oil by acetylation, transesterification and hydrogenation or combinations thereof, wherein the acetylation is carried by reacting the vegetable oil or hydrogenated vegetable with acetic anhydride at temperature in the range of 40-120°C, transesterification is accomplished by reacting with a monohydric alcohol having 5-10 carbon atoms, hydrogenation is carried out in presence of a catalyst and hydrocarbon solvent having 5-8 carbon atoms preferable n-hexane or heptane at 35-200°C at 1-30 bar pressure, and purifying the lubricant by treatment with fullers earth.
In an embodiment of the present invention the vegetable oil is preferably castor oil.
In another embodiment of the present invention the transesterification of the vegetable oil is done with a monohydric alcohol having 5-10 carbon atoms.
In yet another embodiment of the present invention the hydrogenation step is carried out in presence of a catalyst to obtain the hydrogenated oil having iodine value of less than 70.
In still another embodiment of the present invention the degumming and purification of vegetable oil is accomplished by dissolving the oil in isopropanol in the ratio of 1-5 wt/wt followed by cooling to 10-15°C, filtering the mixture and removing the solvent by distillation.
In still another embodiment of the present invention the hydrogenation is carried out in pressure of a catalyst and a hydrocarbon solvent having 5-8 carbon atoms preferably n-hexane or n-heptane at a temperature preferably in the range of 45-180°C at a pressure preferably at 3-26 bar.
In still another embodiment of the present invention the acetylation is carried out by reacting the vegetable oil or hydrogenated vegetable oil with acetic anhydride at a temperature preferably in the range of 40-120°C.
In still another embodiment of the present invention the purification of the lubricant base oil is obtained by treating with fullers earths.
In still another embodiment of the present invention lubricant prepared is useful for lubricant formulations for application in automotive lubricants, gear oil, cutting oil, turbine oil, hydraulic oil, greases and metal forming oil as well as general purpose lubricant.
It will be apparent from the foregoing that the present invention provides biodegradable base oils prepared form modified vegetable oil, particularly castor, useful for preparing lubricant formulations for automotive, and industrial applications. The lubricant base oils prepared according to the present invention exhibit improved lubrication properties over the neat castor oil in terms of improved viscosity index, pour point and oxidation stability and have excellent biodegradability and non-toxic.
The invention is described by the following example, which are given only for the purpose of illustration and are not intended to limit the scope of the invention.
Example-1
466 gm of castor oil was taken in jacketed stirred reactor and heated slowly to 40-50°C. To this 153 g of acetic anhydride was added drop wise over a period of one hour. The temperature was slowly raised to 120°C and maintained for 3 h with constant stirring. The liquid thus obtained is distilled to remove acetic acid and the product left behind was washed with hot water to remove traces of acid to pH 6-7. The liquid after washing is dissolved in toluene and refluxed in Dean Stark trap to remove water. The toluene is distilled off. Last traces of toluene were removed by distillation under vacuum (-20-50 mm Hg). The dried product (acetylated castor oil) is treated with fullers earth to remove any acidity and colouring materials to obtain a straw coloured acetylated castor oil.
The acetylated castor oil thus obtained had the following characteristics:
Viscosity, 40°C (cSt) : 17.6
Viscosity, 100oC (cSt) : 15.70
Viscosity Index : 142
Pour Point, °C : Iodine value : 64
AcidNo.mgKOH/g : Oxidation stability at 95°C, 120 h: Viscosity at 100°C (cSt) before and after test was
15.75 and 14.67 respectively.
Example - 2
Procedure of example-1 was repeated except that in place of castor oil, hydrogenated castor oil was taken and the reaction temperature was kept at 80-85°C. The liquid
product thus obtained (acetylated hydrogenated castor oil) had the following lubricant characteristics.
Viscosity, 40°C (cSt) : 92.0
Viscosity, 100°C (cSt) : 13.6
Viscosity Index : 150
Pour point, °C : -25
Iodine value : Acid No., mg KOH/g : Oxidation stability at 95°C, 120 h: Viscosity at 100°C (cSt) before and after test was
13.60 and 14.13 respectively.
Example - 3
Castor oil (600 g) was taken in a stirred autoclave. To this 600 g of n-heptane and 15 g of Raney Nickel were added. The contents were heated to 130°C and after 3 purges with hydrogen, the autoclave was filled with hydrogen upto 15 bar. The temperature and pressure were kept constant for 6 h. After cooling and releasing the pressure the contents of the autoclave were filtered to remove Raney Nickel, the filtered liquid was subjected to distillation to remove n-heptane. The remaining oily portion (hydrogenated castor oil) obtained after distillation had an iodine value of Ethyl hexyl alcohol (431 g) was refluxed separately with sodium metal (5g) till it dissolved to give clear solution. 520 gm of the Hydrogenated Castor oil was melted and added to 431 gm of sodium treated ethyl hexanol. The mixture was refluxed at 180-200°C for 30 hours. Part of the glycerol was recovered as a lower layer during this operation. Excess of Ethyl hexyl alcohol/ nonyl alcohol was removed by distillation under vacuum at 10 mm. pressure (120-130°C). The remaining contents were kept at 120°C and treated with steam for 1 to 2 hours. The lower layer containing glycerol and hydrolysed sodium ethyl hexanoate/ sodium nonanoate was neutralized with hydrochloric acid to pH 6-7. The contents were allowed to stand for 2 to 3 hours and the lower layer containing remaining of glycerol with drawn. The upper layer was dissolved in Toluene and water was removed by Dean and Stark trap. The dried upper layer (412 gm) was treated 110 gm of Acetic anhydride by drop wise addition at 40°C for 1 hour followed by reflux of the content with constant stirring at 110-120°C.
The toluene and Acetic acid was distilled off. The remaining contents were washed with hot water to pH 6-7. The product was dried under vacuum at 70-80°C to remove traces of water.
Viscosity, 40°C (cSt) : 31.10
Viscosity, 110°C (cSt) : 6.80
Viscosity Index : 187
Pour point, °C : Iodine value : Acid No., mg KOH/g : Oxidation stability at 95°C, 120 h: Viscosity at 100°C before and after test was 6.8 and 7.16 respectively.
Example - 4
Procedure of example - 3 was repeated except in place of ethyl hexyl alcohol, 475 g of sodium treated nonyl alcohol (2,6 dimethyl heptanol) was taken. The lubricant characteristics of the product obtained were as follows:
Viscosity, 40°C (cSt) : 48.06
Viscosity, 100°C (cSt) : 8.26
Viscosity Index : 146
Pour point, °C : Iodine value : Acid No., mg KOH/g : Example - 5
Procedure of exaple-4 was respected except in place of ethyl hexyl alcohol 2-pentyl alcohol was taken. The lubricant characteristics of the product obtained were as follows:
Viscosity, 40°C (cSt) : 18.16
Viscosity, 100°C (cSt) : 4.39
Viscosity Index : 160
Pour point, °C : Iodine value : Acid No., mg KOH/g :

We Claim
1. A process for the preparation of liquid lubricants from non-edible vegetable oils which comprises degumming and purification of vegetable oi! by dissolving the oil in isopropanol in the ratio of 1-5 wt./wt followed by cooling to 10-15°C for 2-6 hour, filtering the mixture and removing the solvent, modifying the purified vegetable oil by acetylation, transesterification and hydrogenation or combinations thereof, wherein the acetylation is carried by reacting the vegetable oil or hydrogenated vegetable with acetic anhydride at temperature in the range of 40-120°C,ransesterification is accomplished by reacting with a monohydric alcohol having 5-10 carbon atoms, hydrogenation is carried out in presence of a catalyst and hydrocarbon solvent having 5-8 carbon atoms preferable n-hexane or heptane at 35-200°C at 1-30 bar pressure, and purifying the lubricant by treatment with fullers earth.
2. A process as claimed in claim 1 wherein the vegetable oil is preferably castor oil.
3. A process as claimed in claims 1 and 2 wherein the transesterification of the vegetable oil is done with a monohydric alcohol having 5-10 carbon atoms.
4. A process as claimed in claims 1 to 3 wherein the hydrogenation step is carried out in presence of a catalyst to obtain the hydrogenated oil having iodine value of less than 70.
5. A process as claimed in claims 1 to 4 wherein the degumming and purification of vegetable oil is accomplished by dissolving the oil in isopropanol in the ratio of 1-5 wt/wt followed by cooling to 10-15°C, filtering the mixture and removing the solvent by distillation.
6. A process as claimed in claims 1 to 5 wherein the hydrogenation is carried out in pressure of a catalyst and a hydrocarbon solvent having 5-8 carbon atoms preferably n-hexane or n-heptane at a temperature preferably in the range of 45-180°C at a pressure preferably at 3-26 bar.
7. A process as claimed in claims 1 to 6 wherein the acetylation is carried out by reacting the vegetable oil or hydrogenated vegetable oil with acetic anhydride at a temperature preferably in the range of 40-120°C.
8. A process as claimed in claims 1 to 7 wherein the purification of the lubricant base oil is obtained by treating with fullers earths.
9. A process as claimed in claims 1 to 8 wherein lubricant prepared is useful for lubricant formulations for application in automotive lubricants, gear oil, cutting oil, turbine oil, hydraulic oil, greases and metal forming oil as well as general purpose lubricant.
10. A process for the preparation of liquid lubricants from non-edible vegetable oils substantially as herein described with references to the examples.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=drrYt4vkORvj3XUX6p9Uhg==&loc=+mN2fYxnTC4l0fUd8W4CAA==

« Previous Patent

Next Patent »

Patent Number

271024

Indian Patent Application Number

365/DEL/2004

PG Journal Number

06/2016

Publication Date

05-Feb-2016

Grant Date

29-Jan-2016

Date of Filing

05-Mar-2004

Name of Patentee

CENTER FOR HIGH TECHNOLOGY

Applicant Address

Ministry of Petroleum & Natural Gas (Govt. of India) Scope Complex, Lodhi Road, New Delhi-110 003

Inventors:

#	Inventor's Name	Inventor's Address
1	VIJAY KUMAR CHHIBBER	INDIAN INSTITUTE OF PETROLEUM, DEHRADUN-248005, INDIA.
2	ASHOK KUMAR GUPTA	INDIAN INSTITUTE OF PETROLEUM, DEHRADUN-248005, INDIA.
3	ONKAR NATH ANAND	INDIAN INSTITUTE OF PETROLEUM, DEHRADUN-248005, INDIA.
4	JAIDEEP MEHTA	INDIAN INSTITUTE OF PETROLEUM, DEHRADUN-248005, INDIA.

PCT International Classification Number

C 10 M 105/32

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA