Classifications

• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11C—FATTY ACIDS FROM FATS, OILS OR WAXES; CANDLES; FATS, OILS OR FATTY ACIDS BY CHEMICAL MODIFICATION OF FATS, OILS, OR FATTY ACIDS OBTAINED THEREFROM
  • C11C1/00—Preparation of fatty acids from fats, fatty oils, or waxes; Refining the fatty acids
  • C11C1/08—Refining
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11B—PRODUCING, e.g. BY PRESSING RAW MATERIALS OR BY EXTRACTION FROM WASTE MATERIALS, REFINING OR PRESERVING FATS, FATTY SUBSTANCES, e.g. LANOLIN, FATTY OILS OR WAXES; ESSENTIAL OILS; PERFUMES
  • C11B3/00—Refining fats or fatty oils
  • C11B3/02—Refining fats or fatty oils by chemical reaction
  • C11B3/08—Refining fats or fatty oils by chemical reaction with oxidising agents
• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D13/00—Making of soap or soap solutions in general; Apparatus therefor
  • C11D13/02—Boiling soap; Refining
  • C11D13/06—Bleaching of soap or soap solutions

Definitions

• This invention relates to the treatment of soapstock and in particular to the treatment of soapstock to obtain good colored soaps therefrom.
• Vegetable and animal oils as extracted from plant or animal tissue usually contain free fatty acids and are usually treated with an aqueous alkali such as caustic soda to remove such free fatty acids when it is desired to use the oil for edible purposes.
• the treatment with alkali results in a refined oil and an aqueous phase, usually referred to as soapstock.
• soapstock contains, in a concentrated form, dirt or coloring matter previously present in the unrefined o l, together with a considerable quantity of occluded neutral oil.
• soapstock is added to charges of oil to be saponified in a soap making process, the resulting soap from such charges is of poor color due to high concentrations of dirt and coloring matter present in the soapstock. If a soap of good color is desired it is possible to bleach the oil mixture from which the soap is to be obtained with a bleaching earth.
• the soapstock instead of being added to a soap charge, the soapstock may be treated with a mineral acid such as sulfuric acid to release the fatty acids from the soap. After separation of the aqueous phase, a mixture consisting of the released fatty acids and the occluded neutral oil is obtained. As the proportion of fatty acids in this mixture is considerably higher than in the original unrefined oil, it is usual to refer to this oil as acid oil. This splitting of soapstocks may be a costly and laborious operation.
• Such acid oil that is oil containing a high proportion of fatty acids, will also contain a proportion of the dirt and undesirable coloring matter present in the original oil.
• soapstock it is sometimes added to the charges of oil used in soap making.
• the resulting soap from such a charge is also of poor color.
• the original oil and the acid oil from the soapstock or an oil blend containing this acid oil has to be bleached with a bleaching earth.
• the bleaching by means of bleaching earth of oils containing free fatty acids such as the above described acid oils or blends of oil containing such acid oil is a laborious and costly process involving filtering of the oil from the earth. It also involves a treatment of the spent earth to recover the considerable amount of oil which is adsorbed by the earth during the treatment. Consequently, earth bleaching of oils is adopted in the soap making industry only when it is desired to produce soaps of the very highest quality, for example, toilet soaps.
• the present invention provides a process of bleaching soapstocks obtained in the alkali-refining of animal and vegetable oils which process comprises contacting the soapstock with a hypochlorite in the presence of an alkali metal chlorite.
• hypochlorite and chlorite which are preferably sodium salts, may both be used in the form of their aqueous solutions. If desired, however, the hypochlorite may be formed in situ in the mixture under treatment; for example, when the hypochlorite is sodium hypochlorite, by adding sodium hydroxide to the soapstock and passing chlorine gas through it.
• the chlorite might also be formed in situ by passing a suitably diluted chlorine dioxide gaseous mixture into soapstock containing an alkali.
• the amount of chlorite used is preferably between 0.1% and 10% and the amount of aqueous hypochlorite, containing about 14% available chlorine, is preferably between 0.1% and 20%, i. e., from about 0.02 to 3% hypochlorite, expressed as alkali metal hypochlorite, all figures being based on the total weight of soapstock. For best results, the amount of chlorite is 0.5%.
• the chlorite may be added to the soapstock before, with or after the hypochlorite.
• the chlorite and hypochlorite solutions are mixed immediately prior to the addition to the soapstock.
• the temperature of the soapstock should be between 40 C. and C. and is preferably about 60 C., while the time of contact with the chlorite and hypochlorite is preferably between about 0.5 minutes and 30 minutes. When carrying out the treatment batchwise optimum results are obtained when the time of contact is about 15 minutes.
• the time of contact can be relatively short is advantageous in that it enables a stream of soapstock and a stream of hypochlorite-chlorite to be passed into a convenient form of mixing device, such as a centrifugal pump, from which a substantially bleached soapstock will issue without having been violently agitated.
• a convenient form of mixing device such as a centrifugal pump
• the process of the invention can be used to supply directly to the saponification stage of a continuous soap making process a stream of bleached soapstock and removes any limitation on the amount of soapstock which may be used in such a continuous soap making process.
• This invention has the advantage that it permits the resultant soapstock to be used directly in the manufacture of good colored soaps, thereby avoiding the necessity of submitting them to the above described splitting with mineral acid to produce acid oils.
• the fact that the soapstock which contains in a concentrated form all the impurities originally present in the unrefined oil can be bleached to give a soapstock of good color and ultimately be used in conjunction with the normal oil blends for the production of good colored soaps, and that both DEl-liibii HUUi i the color of the soapstock and soap does not show any great tendency to revert is surprising, especially when it is remembered that no violent agitation need be employed in the process of the present invention. The agitation need be sufficient only to insure uniform dispersion of the soapstock with the chlorite and hypochlorite.
• EXAMPLE 1 One hundred (100) parts of palm oil soapstock containing from 40 to 50% total fatty matter and having a soap to oil ratio of 1.5:1 are heated to 60 C. in a glass or other chemically-resistant vessel fitted with a mechanical agitator. 0.5 part of sodium chlorite dissolved in water to form a 50% solution are mixed with parts of aqueous sodium hypochlorite having an available chlorine content of 14%. The mixture is added to the soapstock immediately after formation, the soapstock being stirred continually during the addition. The mixture is agitated for 15 minutes at 60 C. before being saponified into a fully saponified soap.
• soaps from red palm oil soapstock treated according to the present invention are much lighter in color than soaps from the unbleached soapstock or hypochlorite bleached soapstock or soapstock from earth bleached oils.
• Example 2 illustrates the formation of the hypochlorite in situ.
• One hundred parts of red palm oil soapstock used in Example 1 are heated to 60 C. as described in Example 1.
• 0.5 parts of sodium chlorite dissolved in suflicient water to form a 50% solution are added to the soapstock, the soapstock being agitated during the addition.
• the mixture is kept at 60 C. while rsufiicient sodium hydroxide solution is added to give, after reaction with chlorine gas, the equivalent of a liquor containing 5% sodium hypochlorite based on the weight of the soapstock.
• the resultant mixture is passed through any enclosed mixing device of chemically-resistant imaterial, such as a centrifugal pump.
• EXAMPLE 5 This example illustrates the addition of the hypochlorite after the chlorite.
• 100 parts of red palm oil soapstock are treated at 60 C.
• sodium chlorite added in the form of a 50% aqueous solution in a reaction vessel such as is mentioned in Example 1 and fitted with mechanical agitation.
• 5 parts of sodium hypochlorite liquor containing approximately 14% by weight of available chlorine are added while the reaction mixture is being agitated.
• Agitation is continued as in Example 1 and then fully saponified soap is prepared from the mixture by saponification. Lovibond measurements on an alcoholic solution of the resultant soap are carried out as well as on alcoholic solutions of soaps from untreated soapstock and of soaps from soapstock treated with sodium hypochlorite liquor.
• EXAMPLE 6 This example illustrates the short time of contact required when treating soapstock according to the present invention.
• 100 parts of palm oil soapstock containing 30 parts of soap and 40 parts of palm oil were heated to between 60 and 65 C. in a glass or other chemically-resistant vessel fitted with a mechanical agitator.
• 0.5 parts of sodium chlorite dissolved in water to form a 50% solution were mixed with 5 parts of sodium hypochlorite liquor having an available chlorine content of 14%.
• Samples were withdrawn from the reaction vessel at intervals of time shown in Table 6 below. These samples were examined for color to test the speed of the bleaching reaction.
• the soapstock treated according to the invention may be derived from any animal or vegetable oil.
• oils are peanut oil, palm oil, rapeseed oil, coconut oil, cotton seed oil, soybean oil, fish oil and like oils.
• a process of bleaching soapstock which comprises contacting soapstock, in indiflerent order, with an alkali metal hyprochlorite and an alkali metal chlorite in aqueous solution at a temperature from about 40 to C., the amount of chlorite being from about 0.1 to 10% by weight of the soapstock and the amount of hypochlorite, expressed as alkali metal hypochlorite, being from about 0.02 to 3% by weight of the soapstock.

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• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Wood Science & Technology (AREA)
• Organic Chemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Microbiology (AREA)
• Fats And Perfumes (AREA)
• Detergent Compositions (AREA)

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ID=9779177

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Citations (8)

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• 1954
  • 1954-02-16 GB GB4545/54A patent/GB762688A/en not_active Expired
• 1955
  • 1955-01-13 US US481709A patent/US2810735A/en not_active Expired - Lifetime
  • 1955-01-13 US US481710A patent/US2802848A/en not_active Expired - Lifetime
  • 1955-02-15 DE DEU3207A patent/DE1010686B/de active Pending
  • 1955-02-15 CH CH336538D patent/CH336538A/de unknown
  • 1955-02-15 FR FR1136264D patent/FR1136264A/fr not_active Expired
  • 1955-02-15 CH CH334640D patent/CH334640A/de unknown
  • 1955-02-16 BE BE535776A patent/BE535776A/xx unknown
  • 1955-02-16 BE BE535775A patent/BE535775A/xx unknown

Patent Citations (8)

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