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 bleaching of soap, particularly the bleaching ofsoap with an alkali metal hypochlorite.
• the lye which. separates from the grained soap has an-unspent alkali content which is usually higher in the case of continuous processes than in the case of batch processes, as Well as any impurities such as dirt and coloring matter present in the oil prior to saponification. It is uneconomic to discharge this lye to glycerine recovery without recovering alkali.
• the unspent alkali in such lye may be neutralized by mixing the lye with an oilhaving a high free fatty acid content. The free fatty acid in this oil :neutralizes the alkali to form a neutral oil-soap mixture.
• This neutral oil-soap mixture containing all the dirty impurities present in the original oil is then treated, for example, by 'centrifuging to remove the major part of the aqueous con stituents and the dirty impurities.
• the oil-soap mixture is then added to the oil being saponified in the continuous soap-making process. Although most of the dirt and other impurities is removed from the oil-soap mixture before passing into the continuous soap-making process, a certain amount of impurities is not removed and therefore impurities are continuously being fed back into the soap-making process. Over a period of time there is 2,892,348 Patented Aug.
• the present invention provides aprocess of preparing light-colored soap which includes the steps of contacting an oil, containing free fatty acid and from which the soap is to be formed, with a chlorite, then saponifying the'chlorite-treated oil with alkali and bleaching the resultant soap with ahypochlorite.
• the chlorite may be an alkali metal chlorite, such as sodium or potassium chlorite, and is preferably added to the oil in the form of an aqueous solution.
• the hypochlorite may be an alkali metal chlorite such as sodium or potassium hypochlorite, and is preferably added'to'the oil in the form of anaqueous solution.
• thehypochlorite and chlorite may be formed in situ-in the soap and oil respectively, for example, in the case of the hypochlorite, by addingan alkali, such as sodium hydroxide, to the soap and' passing chlorine gas'through it.
• the process of the invention may be used for bleaching soapsfrom any vegetable or animal oils containing free'fatty acids; that is to say, it canbe used for so'aps from unrefined oils which generally'cont'ain free acids: It is of particular advantage for decolorizing soaps-made from oil blends which include the acid oils resulting from the splitting of soapwhen the soapstock obtained from crude oils are alkali refined.
• agitation of thesoap andhypochlorite does not have to be violent, and does not involve the use of streams means-that'the operations of treating the oil with chlorite, saponifying and treating the soap with hypochlorite may be carried outin a single vessel, for example, a soapmaking kettle; insoapmaking may be used for saponification.
• a single vessel for example, a soapmaking kettle; insoapmaking may be used for saponification.
• the alkali metal hydroxides such as sodium and potassium hydroxide can be used to produce-water soluble soaps whereas alkaline-earth metal hydroxides such as calcium and barium hydroxide canbe used'toproduce water insoluble soaps.
• Such a vessel should preferably be acid-resistant since the product of the chlorite addition may. attack non-resistant materials and this may, result in lessJeflicient' decolorization of the finished soap than'would otherwise be obtained.
• the saponification procedure is conventional.
• the amount of chlorite used may be between 0.1% and "10% based'onthe total Weight of oil and fatty acid to "be” reacted with alkali; For'best results the amount of chlorite should 'be 0.5%.
• the amount of aqueous hypochlorite-(l4% available chlorine) used is preferably betweenv0.2-5% and 20%, i. e., from about 0.04 to 3% of hypochlorite expressed as alkali metal hypochlorite, based on thetotalweight of oil and fatty acid'previously treate'dwith chlorite and for best results 7.5% of aqueous hypochlorite should 'be used.
• the temperature ofboth" the chlorite treatment and the hypochlorite bleaching should bev between40 C. and 100 C. and preferably about C.
• the time of contact shouldbebetween-d- Any alkali customarily used minutes and 300 minutes and preferably about 30 minutes, when carrying out the process of the invention batchwise. It is preferred to keep the time of contact between the soap and hypochlorite as short as possible.
• a stream of soap made from chlorite-treated oil containing free fatty acid may be mixed by a suitable form of mixing device with a stream of aqueous solution of hypochlorite. No violent agitation of the soap and hypochlorite is necessary to give a bleached soap, the color of which shows less tendency to deteriorate on standing than do soaps bleached by hypochlorite alone.
• the process of the present invention is particularly suitable for combining with the process of the aforesaid copending application.
• soapstock treated according to the process of the copending application may be mixed with the chlorite-treated oil containing free fatty acids prior to the reaction with alkali.
• Such soapstock which contains a considerable proportion of neutral oil is thus directly used in a soap-making process. Hitherto it has been necessary to split such soapstock with mineral acid to covert it into an acid oil by a difiicult and prolonged process, and the acid oil so produced was utilized in the soap-making process.
• the soapstock may be decolorized by the process of the copending application prior to mixing with the chlorite-treated oil utilized in the present invention.
• the untreated soapstock and material which is to be chloritetreated may be mixed and chlorite and hypochlorite added to the mixture provided the amount of soapstock in the mixture is sufiicient to render the mixture neutral or alkaline.
• the soap formed after reaction with alkali in this embodiment of the present invention has then, of course, to be treated with hypochlorite.
• the process of the present invention is also particularly useful in overcoming the color build-up resulting from the incorporation of the products of neutralization of the lye encountered in the soap-making processes, and which is not overcome by the hypochlorite treatment of soap even when this treatment involves intense agitation such as is mentioned above.
• Example 1 This illustrates the treatment of a crude oil blend to which soapstock has been added.
• An oil blend of the following composition was prepared:
• Example 2 Soaps prepared in a similar manner to that of the last line of the above table were kept for 12 and 15 days, respectively, at 35 C. and 75% relative humidity. Lovibond readings on 10% alcohol soap solutions of samples were taken before and after standing. These readings are given in the following tables, those in Table II relating to storage for 12 days and those in Table III to storage for 15 days:
• Example 3 This illustrates the formation of hypochlorite in situ.
• An oil blend was prepared with the following composition:
• Example 1 The soap was then mixed with about of its weight of water containing the requisite amount of sodium hydroxide which when reacted with chlorine would form the equivalent of about 5% of the weight of soap (having 60% total fatty matter) of sodium hypochlorite liquor having about 14% by weight available chlorine.
• This mixture was heated to 60 C. and passed through a suitable enclosed mixing apparatus, for example, a centrifugal or other suitable pump.
• the necessary amount of chlorine gas to react with sodium hydroxide to form the equivalent of about 5% of the sodium hypochlorite liquor (14% by weight available chlorine) based on the weight of soap having a 60% total fatty matter, is fed into the stream of soap/ sodium hydroxide mixture entering the mixing apparatus, for example, into the inlet side of the pump.
• the bleached soap passes continuously from the outlet of the mixing apparatus and is then subjected to the normal finishing operations for the production of soap. Analogous experiments were carried out with concentrated oil blends and the results obtained are expressed in the fol-
• the oil treated according to the present invention can be any of those customarily used in making soap. Examples of preferred fatty oils are rapeseed oil, peanut oil, palm oil, coconut oil, tallow, olive oil, palm kernel oil and like oils.
• a process of preparing light-colored soaps which includes the steps of contacting a glyceride oil containing free fatty acid with an alkali metal chlorite, saponifying the chlorite-treated oil with alkali and bleaching the resultant soap with from about 0.04% to about 3% of an alkali metal hypochlorite based on the total weight of chlorite-treated oil.
• a process of preparing light-colored soaps which includes the steps of contacting a glyceride oil containing free fatty acid with from about 0.1 to 10% of an alkali metal chlorite based on the weight of oil, saponifying the chlorite-treated oil with alkali and bleaching the resultant soap with from about 0.04% to about 3% of an alkali metal hypochlorite based on the total weight of chlorite-treated oil.
• a process of preparing light-colored soap which includes the steps of contacting a glyceride oil containing free fatty acid with an aqueous solution of an alkali metal chlorite at a temperature between about 40 and 100 C., saponifying the chlorite-treated oil with alkali and bleaching the resultant soap by contact with an aqueous solution of an alkali metal hypochlorite at a temperature between about 40 and 100 C., said aqueous solution of alkali metal hypochlorite furnishing from about 0.04% to about 3% of an alkali metal hypochlorite based on the total weight of chlorite-treated oil.

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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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Citations (3)

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

Patent Citations (3)

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