Title of Invention


Abstract A method of bleaching fatty acids having C6-C24 carbon atoms, containing impurities such as pigments and decomposed proteins and carbohydrates essentially consisting of the following steps: a) heating said fatty acids to 50 - 90 °C; b) adding 0.5 - 5 % of hydrogen peroxide at 50% strength w/w at a dropwise rate of 0.2 ml per minute; c) maintaining temperature between 50 - 90 °C for 0.5-8 hours; d) stirring the reaction mixture and drying under reduced pressure, maintaining the said temperature.
Full Text The Patent Act, 1970
Complete Specification
(See Section 10; Rule 13)
A method of bleaching fatty acids
Godrej Soaps Ltd., Eastern Express Highway, Vikhroli, Mumbai 400 079 Maharashtra, India.
An Indian Company
The following specification particularly describes the nature of this invention and the
manner in which it is to be performed. GRANTED

The present invention envisages a method of bleaching fatty acids comprising of reacting the fatty acids with bleaching agents, preferably hydrogen peroxide.
Non Fatty Acids in Oils. Fats & Fattv Acids
Crude fats and oils are made up of free fatty acids, glycerides, phosphatides, sterols, tocopherols, tocotrienols, hydrocarbons, pigments (gossypol and chlorophyll), sterol glucosides & esters, and protein fragments, as well as resinous and mucilaginous material. Free Fatty Acids and Partial Glycerides are formed from crude oil crops, which contain lipase enzymes that cleave triglycerides. They may be diglycerides and monoglycerides. Free fatty acid concentrations are undesirable because they cause high losses during further processing of the oil. Glycerides esterified by fatty acids at the 1,2 positions and a phosphoric acid residue at the 3 position constitute the class called phospholipids. In older literature and in commercial practice, these materials are described as phosphatides. The most important one is Lecithin. Sterols are tetracyclic compounds derived biologically from terpenes. They are fat-soluble and therefore are found in small quantities in fats and oils. The hydroxyl group can be free or esterified with a fatty acid. Plants contain sterols such as Beta-Sitosterol and Stigmasterol. Algae and plants used as sources of edible oils contain tocopherols, phenolic materials that function as antioxidants. Carotenoids are tetraterpene hydrocarbons formed by the condensation of eight isoprene units. Another class of compounds, the xanthophylls, is produced by hydroxylation of the carotenoid skeleton. Beta-Carotene is the best known component of the carotenoids because it is the precursor for vitamin A. Carotenoid pigments are unstable toward heat, light, and

oxidation chlorophyll is composed of a porphyrin ring system, in which magnesium is the central metal atom, and a phytol side chain which imparts a hydrophobic character to the structure. Conventional bleaching clays are not as effective for the removal of chlorophylls as for red pigments and specialized acid-activated adsorbents or chemical agents are required. Most of these impurities are objectionable since they render the oil, fat or fatty acid dark coloured, cause it to foam or smoke, or are precipitated when the product is heated in subsequent processing operations.
Fatty Acids
The fatty acids applied to the present invention includes fatty acids having about 6 -24 carbon atoms, which are obtained by the hydrolysis of natural fats and oils such as vegetable fats and oils. These fatty acids are, for example, canola oil fatty acid, coconut oil fatty acid, corn oil fatty acid, mustard oil fatty acid, palm oil fatty acid, rapeseed oil fatty acid, soybean oil fatty acid, tall oil fatty acid and either their individual fatty acids or their most common fractions like valeric acid, caproic acid, caprylic acid, pelargonic acid, capric acid, caprylic-capric, lauric acid, myristic acid, lauric-myristic, palmitic acid, stearic acid, palmitic-stearic, oleic acid, linoleic acid, linolenic acid, arachidic acid, behenic acid, erucic acid & lignoceric acid.
Colours & Colouration
Green colouration, present in many fatty acids poses a particular problem in oil extracted from immature or damaged soybeans. Chlorophyll is the compound

responsible for this defect. Carotenoids contain conjugated double bonds, a strong chromophore which produces red and yellow coloration in vegetable oils. Oxidation has an important effect on the colour of fatty acids. While air oxidation bleaches the carotenoid pigments, it develops the colour of other types of colouring materials. The partial oxidation of vegetable oils or fatty acids causes an increase in their red-yellow colour, due to formation of the chroman-5,6-quinones. The poor bleach colours are obtained because new pigments develop as the old ones are adsorbed. Oxidation of tocopherol leads to ring opening and the formation of tocoquinonos that show an intense red color. Traces of iron and some other metallic contaminants greatly favor color development in fatty acids. Oils from badly damaged seeds contain brown pigments which get carried over into the fatty acids are evidently derived from decomposed proteins and carbohydrates. (Maillard Reaction)
The object of refining and bleaching is to remove the objectionable impurities in the fatty acid with the least possible damage to the unsaturated fatty acids and with the least possible loss of the product. As used here, the term "refining" is solely used for oils and refers to any purifying treatment used to remove free fatty acids, phosphatides, or mucilaginous material, or other gross impurities in the oil. It excludes "bleaching" and also "deodorization" The term "bleaching" is used for both oils & fatty acids and is reserved for treatment designed solely to reduced the colour of the oil or fatty acid. The term "deodorization" is solely used for oils and involves a process where the volatile impurities like free fatty acids, hydrocarbons and other

break-away groups are removed from an oil by high temperature & high vacuum distillation. Some other methods, by default, serve the purpose of purification. The carotenoid pigments are not altogether stable to heat and are converted to colourless compounds by hydrogenation; hence some bleaching effects are incidental to the operations of hydrogenation and deodorization. In the process of deodorization, heat destroys the red carotenoid pigments (heat bleaching).
Light colour and a clear and bright appearance have long been associated with oil and fatty acid quality. Removal of pigments of accomplished by absorption on solid materials (absorption bleaching) or by treatment with oxidizing agents such as peroxide or hypochlorite solutions (chemical bleaching).
Adsorptive Bleaching
Bleaching absorbents are derived from bentonite or montmorillonite clays. The activity of these clays may be increased by treatment with acid. In addition to removing pigment, an important function of bleaching clays is the reduction of concentrations of metals such as copper, iron, manganese, and cobalt which catalyze oxidation of fatty acids and reduce their shelf life.
Activated carbon is an effective bleaching agent but also absorbs a high percentage of its own weight of the product resulting in increased product loss. Hence carbon may

be used effectively in small amounts in combination with activated bleaching earths. Absorbents may be selected according to the specific pigments to be removed from a fatty acid. Carotenoid pigments, which produce red colours are effectively removed by activated clays. Carbon is quite effective for removing green chlorophyll pigments from soybean fatty acids obtained from damaged beans. Brown pigments, which may be extremely difficult to remove, result from oxidation of carotenoids and are encountered in fatty acids from abused oils.
Bleaching Conditions
The type of adsorbent and concentration are selected considering activity, adsorbent cost, product loss, and metal removal. The amount of adsorbent required for any given bleaching operation will vary greatly with the activity and the nature of the adsorbent, the variety of the fatty acid, the color of the unbleached fatty acid, and the color desired in the bleached fatty acid. In general, however, the range of clay used is 0.15 - 3 wt %. Small amounts (5 to 10 wt % of the amount of earth used ) of activated carbon may be added to the bleaching clay, where chlorophyll pigments impart agreenish color to the fatty acid. Unless bleaching is conducted with the rigid exclusion of oxygen the normal color reduction, brought about by the adsorption of pigments will be considerably affected. This is mainly due to the theory of oxidative stabilization of pigments with bleaching earths. It has been established that oils bleached much better under vacuum than when exposed to the atmosphere. This true even when the fatty acids were characteristically "nonreverting" in colour, that is, when mild oxidation of the fatty acid brought about a reduction rather than an

increase in the colour general, there is no highly critical temperature for optimum bleaching result, and in most plants bleaching is carried out uniformly at a temperature in the neighborhood of 80 - 95 °C. Some activated earths, however, yield slight better results at a lower temperature; hence if the operation is carried under vacuum, so that dehydration of the fatty acid and earth constitutes no problem, temperatures as low as 65 - 75 °C. are recommended. Bleaching adsorbents equilibrate with the pigments in oils quite rapidly. So with reasonably efficient stirring of the slurry a contract time of 0.5 - 1.0 hr. is ample.
Chemical Bleaching
The various chemical bleaching methods applied to fatty all depend on oxidation of the pigments of colourless or lightly coloured materials. Most of the bleaching methods enumerated accomplish considerable reduction of the colour of the fatty acid. In earth bleaching pigments are removed from product. In chemical bleaching the pigments are allowed to remain but are oxidized to a colourless or less coloured form. Chrome bleaching of palm oil was practiced using chemicals like concentrated commercial hydrochloric acid and sodium dichromate. The bleaching of industrial fats with chlorine dioxide, obtained in situ by the action of sulfuric acid on sodium chlorite, has been described by Woodward. The corrosive effects of acid on the equipment can be avoided by using safer gaseous chlorine to liberate the chlorine dioxide The harmful effects of chlorine will still persist. Other harmful, toxic & environmentally unfriendly bleaching agents have included sodium hypochlorite, sodium perpyrophosphate, and potassium permanganate. The best and most safe

chemical bleaching agents are peroxides. Environmental concerns have led many an industry to turn to alkaline solutions of peroxides as a replacement for chlorine. There are also some major bleaching applications where hypochlorite and chlorine dioxide are also being replaced.
Peroxides are one of the most Common bleaching agents. It is the primary bleaching agents in the textile industry, and is also used in pulp, paper, oleochemicals and home laundry applications. In textile bleaching peroxide is the most common bleaching agent for protein fibers and is also used extensively for Cellulosic fibers. Peroxides are also used to bleach solid surfaces such as wood or linoleum, and to improve the colour of oils and waxes. Most peroxides have a high active oxygen content. Of these hydrogen peroxide is the least expensive source of active oxygen commercially available. Moreover it is a liquid, making it convenient for many bleaching applications. Hydrogen peroxide is usually sold in solutions containing 30 - 35 %, 50% or 65 - 70% by weight of the active material. Hydrogen peroxide bleaching is performed in alkaline solution where part of the hydrogen peroxide is converted to the perhydroxyl anion. The perhydroxyl anion is generally believed to be the active bleaching species and its concentration in solution increases with hydrogen peroxide concentration, alkalinity, and temperature. The alkaline agents most commonly used to generate HO2 ions are caustic soda, carbonates, silicates, pyrophosphates, and polyphosphates. Better bleaching is obtained at these alkaline conditions by increasing the temperature and using stabilizers in order to prevent the uncontrolled

decomposition reactions of hydrogen peroxide. Common stabilizers include silicates, pyrophosphates, and polyaminocarboxylates. These stabilizers may be different from those used to stabilize commercial acidic hydrogen peroxide. As a bleaching agent, hydrogen peroxide is much less effective then chlorine or hypochlorite, however, it does have several advantages over these bleaching agents. Hydrogen peroxide causes less damage, is much gentler on material and does not have a strong odour. Final brightening is one of the major applications which also significantly improves brightening stability. Added to its other advantages, hydrogen peroxide is a nonpolluting oxidant which is of significant and increasing importance. Hydrogen peroxide is an ecologically desirable pollution-control agent because it yields only water or oxygen on decomposition.
The Inventive Step
The aspect of the method for bleaching of fatty acids according to the present invention lies in comprising reacting the fatty acids with 0.5 - 5 % of hydrogen peroxide at 50% strength by weight of the fatty acid at a temperature of 50 - 90 °C for 0.5-8 hours recovering a purified fatty acid. After drying or drying & distillation as the need may be. The present invention is a process which employs various steps. The process thus comprises of:
a. Heating the said fatty acid to 50 - 90 °C depending on the titre of the fatty acid
b. Stirring the molten fatty acid blend for though mixing

c. Adding 0.5 - 5 % of hydrogen peroxide (50% strength ) w / w, addition rate being
maintained so as not to raise the temperature of the reaction mixture beyond 100 °C
d. Giving sufficient time for the purification process ranging from 0.5 - 8hours
e. Recovering the purified fatty acid by simple drying or optionally distillation.
The present invention relates to a method of bleaching fatty acids having C6-C24 carbon atoms, containing impurities such as pigments and decomposed proteins and carbohydrates essentially consisting of the following steps:
a) heating said fatty acids to 50 - 90 °C;
b) adding 0.5 - 5 % of hydrogen peroxide at 50% strength w/w at a dropwise rate of 0.2 ml per minute;
c) maintaining temperature between 50 - 90 °C for 0.5 - 8 hours;
d) stirring the reaction mixture and drying under reduced pressure, maintaining the said temperature.
Hydrogen peroxide is a nonpolluting oxidant which is of significant and increasing importance. Hydrogen peroxide is an ecologically desirable pollution control agent because it yields only water or oxygen on decomposition. The other advantages of hydrogen peroxide are its mildness to the fatty acids & the ease of recovery of the purified fatty acid.

Colour Value
Oil refiners and fatty acid manufacturers usually determine the colours, of the lighter refined and bleached oils or distilled fatty acids, by matching in a suitable tintometer a 5.25" column of the melted fat against red and yellow Lovibond colour glasses. The red glasses are standardized by the National Bureau of Standards in terms of the Priest-Gibson N" color scale. The N" scale approximates but does not exactly follow the manufacturers standards. In matching the colour of the sample of the sample of oil or fatty acid, it is necessary to only approximate the yellow colour to obtain a satisfactory match with the red glasses. For higher colour the smaller sized 1"' and the 0.25" columns are used. Crude fatty acids also exhibit a blue tint due to the green pigments.
The following examples are only illustrative and not limiting the scope of the above invention.
Example 1
500 gms. of Hardened Palm Fatty Acid Distillate Fatty Acid (HPFADFA) was taken in a 3-necked flask fitted with a thermometer pocket and over head stirrer with shaft. The material was heated to 85 °C in a constant temperature water bath with continuous stirring. A solution of 10 gms. ( 11.8 ml) of 50 % hydrogen peroxide was taken in a dropping funnel. The addition was started at a dropwise rate and the temperature was maintained between 85 and 90 °C. After the entire amount had been

added the reaction mixture was stirred at 85 °C for 1 hr. The reaction mixture is then dried under reduced pressure at the same temperature of 85 °C. The purified and dried fatty acid is ready for further processing or used as such. The degree of purification is measured by comparing the Lovibond colour of the original and purified fatty acids. The results of the experiment are tabulated in the common table below.
Examples 2 to 15 encompass the principle of Example 1. The variations made are related to either the type of Raw Materials selected or the type of bleaching agent used or the percentage of bleaching agent used or the time of reaction or a combination of any of the above. The results of all the examples have been tabulated in one common table on the following page.

Tabulation of the experimental results


14 CPStFA Peroxide 1% 1" 5.9R+31.0Y 3.0R+12.0Y2hrs
15 CPStFA Peroxide 1% 1" 5.9R+31.0Y 3.8R+19.0Y 1 hr.
HPFADFA = Hydrogenated Palm Fatty Acid Distillate Fatty Acid
HPStFA = Hydrogenated Palm Stearin Fatty Acid
HRBFA = Hydrogenated Rice Bran Fatty Acid
RBOFA = Rice Bran Oil Fatty Acid
PFADFA = Crude Palm Fatty Acid Distillate Fatty Acid
CPStFA = Crude Palm Stearin Fatty Acid
Earth = Acid Activated Bentonite
Carbon = Acid Activated Charcoal
Perborate = Sodium Perborate Tetrahydrate
Peroxide = 50% Hydrogen Peroxide Solution

We Claim :
1. A method of bleaching fatty acids having C6-C24 carbon atoms, containing
impurities such as pigments and decomposed proteins and carbohydrates essentially
consisting of the following steps:
a) heating said fatty acids to 50 - 90 °C;
b) adding 0.5 - 5 % of hydrogen peroxide at 50% strength w/w at a dropwise rate of 0.2 ml per minute;
c) maintaining temperature between 50 - 90 °C for 0.5-8 hours;
d) stirring the reaction mixture and drying under reduced pressure, maintaining the said temperature.
2. A method as claimed in Claim 1, wherein the resulting fatty acid is optionally
Dated this 20th day of June 2001
H . W. Kane Applicant's Agent


241-mum-2000 cancelled page(13-12-2004).pdf

241-mum-2000 claim(13-12-2004).pdf

241-mum-2000 claims (granted)-(13-12-2004).doc

241-mum-2000 correspondence(12-5-2006).pdf

241-mum-2000 correspondence(ipo)(17-11-2004).pdf

241-mum-2000 form 1(16-3-2000).pdf

241-mum-2000 form 1(21-3-2000).pdf

241-mum-2000 form 19(31-7-2003).pdf

241-mum-2000 form 2 (granted)-(13-12-2004).doc

241-mum-2000 form 2(granted)(13-12-2004).pdf

241-mum-2000 form 3(16-3-2000).pdf

241-mum-2000 form 3(21-3-2000).pdf

241-mum-2000 form 3(8-7-2001).pdf

241-mum-2000 form 4(20-6-2004).pdf

241-mum-2000 form 5(20-6-2004).pdf

241-mum-2000 form 6(10-3-2005).pdf

241-mum-2000 power of authority(10-12-2004).pdf

241-mum-2000 power of authority(21-3-2000).pdf

Patent Number 208836
Indian Patent Application Number 241/MUM/2000
PG Journal Number 35/2007
Publication Date 31-Aug-2007
Grant Date 13-Aug-2007
Date of Filing 21-Mar-2000
# Inventor's Name Inventor's Address
PCT International Classification Number C07C 67/48
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA