Soaps from fats

Castile soap is manufactured from olive oil, transparent soap from decolorized fats and liquid green soap from KOH and vegetable oils. Soaps are sometimes superfatted in that they contain some free fatty acid. 

An important reaction of fats is the reverse of ester formation. They hydrolyze, or react with water, just as disaccharides do. Usually hydrolysis is carried out in aqueous Ca(OH)2, NaOH, or KOH solution. Because of long use in the preparation of soap from fats, the alkaline hydrolysis reaction (6) is called saponification. 

Soaps are derived from natural sources such as animal fats. Soap made by boiling animal fat in an alkaline solution obtained from ashes has been known since the time of the ancient Sumerians, 2500 BC. Such soaps... 

Sodium carbonate is an alkali, a strongly basic compound that has a pH of 9 or more in solution. Boiling an alkali with fat makes soap. Chemically, soap contains a long chain of hydrocarbons that repels water but has an affinity for other fatty substances. When treated with alkali, the ends of the fatty chains are modified so that they are attracted to water. A molecule with one end that attracts fatty substances and another end that likes to dissolve in water is ideal for coating dirt particles and floating them away in water. Soap can be made from any kind of fat, whether from kitchen scraps or whale, olive, or palm oil. 

Uses of Soap.—Soap is applied for washing, for fulling weellcn cloths, et cetera, and in medicine. Ils application for washing is founded on two conditions, namely, on its power to remove fatly matters from textile and other materials, and to form therewith an emulsive mass soluble in soapy water and on the readiness with which the neutral salts of fatty acids are decomposed by worm, water into aoid componnds and free alkali, The latter acts upun tho impurities of substances, and forms with them compounds partly soluble, and partly such as will no longer adhere to toxtUo fabrics and other bodies, whilst the separated acid salts of the fatty aoids keep the surface of the material in a smooth condition. 

Making soap from vegetable oil and alkali. Boil a vegetable oil or animal fat with aqueous sodium hydroxide. Cool and add salt to precipitate the soap. 

Lard is a term used for animal fat, usually from pigs. Before the industrial revolution, it was commonly used in place of butter or vegetable oils, which were more expensive. In some cultures today, it is still an important food additive. Lard is also used to make some kinds of soap. 

Tallow is waxy body fat rendered from animal tissue, usually that of beef or sheep. It is isolated by heating, and allowed to solidify. Tallow has been used in leather preparation, as a lubricant, in food preparation, and in making candles and soap. It is used as food for domestic animals, mostly for poultry. Tallow candles bum quickly and have a low melting point. They were generally less expensive than wax candles, and easier to make. Suet is another name for animal fat, usually applied to that from sheep. 

Saponification is the base-promoted hydrolysis of the ester linkages in fats and oils (review Section 21-7B). One of the products is soap, and the word saponification is derived from the Latin word saponis, meaning soap. Saponification was discovered before 500 b.c., when people found that a curdy material resulted when animal fat was heated with wood ashes. Alkaline substances in the ashes promote hydrolysis of the ester linkages of the fat. Soap is currently made by boiling animal fat or vegetable oil with a solution of sodium hydroxide. The following reaction shows formation of soap from tristearin, a component of beef fat. 

Shmuel Krakowski, archives director of Yad Vashem, and Professor Yehuda Bauer finally admitted in 1990 that the Nazis never made soap from human fat (The Jerusalem Post International Edition, 5 May 1990). In a cemetery of Nice (France), there is a monument which bears the following inscription This urn contains soap from human fat manufactured by the Germans of the Third Reich with the bodies of our deported brothers. ... 

The Nazis did not manufacture soap from human fat, and did not kill their victims with Diesel exhaust. All these rumors were circulated in 1942, but we have the duty to thoroughly separate these rumors and fabrications from the facts and truth. Little lies provide fodder for the deniers and act against us. ... 

The two main classes of soaps are toilet soap and industrial soap. Toilet soap is usually made from mixtures of tallow and coconut in the ratios 80-90 10-20. The bar soap includes regular and super fatted toilet soaps, deodorant and antimicrobial soaps, floating soaps, and hard water soaps. The super fatted soaps are also made from a mixture of tallow and coconut oil in ratios 50-60 40-50. All soaps practically contain 10 to 30 percent water and also contain perfume that serves to... 

A commonly used nonfood product derived from coconut oil is soap. Laundry bar soaps made by boiled or cold procedures have excellent lathering property even in moderately hard water. A blend of tallow-coconut oU in ratios from 67 33 to 85 15 form an ideal fat charge for toilet soaps (37). Soap from such blends exhibit desirable characteristics related to lather quickness, low mechanical erosion, and absence of swelling or cracking of soap bars. 

A relationship between peroxide value and anisidine number that is used to measure the rancidity level of fats and oils. It is defined as (2 X PV) + AN. It reflects total oxidation to date. Considered an impurity. High levels of moisture in an oil can lead to deterioration in storage. Soap can be formed when moisture is present in the crude oil and reacts with the free fatty acids and a catalyst (alkali ion), or it can result from incomplete removal of soap from washed refined oil. 

As commercially made by the saponification of fats, soaps are not pure chemical individuals but consist of a mixture of the alkali-metal salts of the several fatty acids contained as esters in the original fat or oil. The composition of soap, therefore, depends upon the composition of the fat from which it is made. As the common fats and oils which are used for this purpose contain, mostly the glycerol esters of palmitic, stearic and oleic acids, the common soaps are mixtures of sodium, or potassium, palmitate, stearate and oleate. We shall consider now,... 

Soaps A class of chemical substances which are metal salts of fatty acids. Pliny (first century a.d) records that the ancient Romans learned the preparation of soap from Nordic tribes, who used a pomade prepared from goat fat and the calcined ashes of beech-wood. Sapo, the Latin word for soap, is derived from the Nordic sepe. The chemistry of soaps was elucidated in the early nineteenth century by French... 

C. Making solid soap from solid animal fat. 

The term extractable substances denotes those substances which are extracted under certain conditions by an organic solvent from a sample of sludge (or water), and which then remain after elimination of the solvent and drying. This group includes oils (both mineral and plant), fats, soaps, waxes, heavy hydrocarbons, tar, etc. The results of the determination of extractable substances are given in mg kg or mg 1 in liquid samples (it is necessary to state the method used). 

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