Saponification of a fat. Soap

Place 5 g. of lard (or any fat or fatty oil), 3 g. of potassium hydroxide and 40 ml. of alcohol in a 250 ml. round-bottomed flask, attach a reflux condenser, and boil for about 30 minutes. The reaction is complete when no globules of oil are present when a few drops of the mixture are mixed with a little water. Distil the reaction mixture (Fig. II, 13, 3) and recover the alcohol dissolve the residue in 75 ml. of hot water. Carry out the following experiments with the resulting solution — 

Drying oils. Place 3 ml. of linseed oil in a test-tube, add about 01 g. of litharge and boil the mixture gently for 10 minutes. When cold, pour a little of the product on a watch glass and spread the oil into a thin film with the aid of a small piece of paper. Pour a little of the untreated linseed oil on another watch glass and spread it out as a thin film. Compare the times taken for the films to become dry. 

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As pointed out in Chapter II. the fatty acids, which, combined with soda or potash, form soap, occur in nature almost invariably in the form of glycerides, i.e., compounds of fatty acids with glycerol, and as the result of saponification of a fat or oil glycerine is set free. 

Saponification (the hydrolysis of a fat to a soap under strongly alkaline BW conditions)... 

Salt Bridge concentrated solution of electrolyte used to complete the circuit in an electrochemical cell that helps to equalize charge distribution in each half cell Saltpeter potassium nitrate, KNO3 Saponification conversion of a fat to soap by reacting with an alkali Saturated solution that contains the maximum amount of solute under a given set of conditions... 

CANDLE.—Read, in connection with the processes described at pages 430,431 —The operations of saponification of the fat, and decomposition of the lime-soap by sulphuric acid, have been hitherto effected in open vessels, under the ordinary pressure of the atmosphere. An improvement on this plan has been recently proposed by M, Delapchiek, of Besangoo, who substitutes dose vessels in Order to saponify the fat. Wash and decompose the lime-soap under a pressure of about twenty-two pounds to the square inch, by which the operations are considerably facilitated, and their duration shortened. The products by this process are said to be superior to those obtained in open vessels, and a considerable economy of flaid is effected. The apparatus consists essentially of a horizontal boiler, with a man-hole and two safety valves at the top, The heat is furnished by a large steam-pipe, running in a depression along the bottom of the boiler. The... 

Ordinary soap is a mixture of the sodium or potassium salts of long-chain carboxylic acids that arise from saponification of animal fat. Draw the structures of soap molecules produced in the following reaction ... 

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. 

In general, two types of chemical reactions are utilized in the manufacture of soap the saponification of triglycerides (fats and oils) and the neutralization of fatty acids (which themselves are produced from the triglycerides by a variety of methods, most notably splitting or hydrolysis of fats and oils with steam under high pressure). Sodium hydroxide (the predominant alkali employed in the manufacture of soaps), potassium hydroxide, sodium carbonate, and triethanolamine are... 

Soap is prepared by the basic hydrolysis or saponification of a triacylglycerol. Heating an animal fat or vegetable oil with aqueous base hydrolyzes the three esters to form glycerol and sodium salts of three fatty acids. These carboxylate salts are soaps, which clean away dirt because of their two structurally different regions. The nonpolar tail dissolves grease and oil and... 

The process was best adapted to fresh fat. Stocks in which hydrolysis occurred were difficult to process because of the formation of soap in the aqueous phase. The soap was derived only from already liberated free fatty acids. Under the mild conditions of this digestion process, there was no appreciable saponification of neutral fat. The fat was also alkali refined to produce a final product free of acidity. A typical final product had a free fatty acid content of 0.01% and a Fovibond color of 2 yellow and 0.3 red. This process gave improved yields over conventional wet rendering (59, 60). 

Insoluble Acids, Hehner Value.—The acids which are set free from the fat or oil by saponification and subsequent acidification, differ in two other respects as well as in their power to absorb halogens. These are, (i) solubility (2) volatility. - Some of the acids, like butyric, are soluble in water while most of them are insoluble. Some, like butyric and lauric, are volatile with steam, others are non-volatile. The determination of the amount of insoluble acids in a fat gives us a value known as the Hehner Value which may be defined as the sum of the insoluble acids and unsaponifiable matter in a fat expressed in per cent. After saponification of the fat the soap solution is acidified and the insoluble fatty acids are collected on a filter paper and weighed. In the case of most of the common fats and oils the Hehner value lies in the neighborhood of 95, with butter fat as the striking exception, with a value of less than 90. The Hehner values which differ much from 95 are given in the table at the end of this section. 

Soap, which is a mixture of sodium and potassium salts of fatty acids, is produced industrially by hydrolysis (saponification) of animal fat using aqueous sodium hydroxide. 

For a long time the soaps of carboxylic acids were manufactured by saponification of natural fats, which are the esters of glycerol and various fatty acids. A large consumption of food materials promoted the development of commercially manufactured synthetic fatty acids (SFA). As shown further down, the unbranched C]0 - C20 synthetic fatty acids can be manufactured by a number of methods and are widely used in surfactant production. 

FIGURE 5.2.1.2 Saponification of a Triglyceride. Treating a fat with a strong base frees fatty acids that can be isolated as sodium salts that can be used as soaps. 

During the last few years, however, there has been a growing attempt to first separate the glycerol from the fatty acids, and then convert the latter into soap by treatment with the carbonates of soda or potash, which are of course considerably cheaper than the caustic alkalies, but cannot be used in the actual saponification of a neutral fat. The two processes chiefly used for this purpose are those in which the reaction is brought about by enzymes or by Twitchell s reagent. 

RNA Ribonucleic acid, a type of nucleic acid, is a single strand of nucleotides containing adenine, cytosine, guanine, and uracU. saponification The reaction of a fat with a strong base to form glycerol and salts of fatty acids (soaps), secondary structure The formation of an a helix, /3-pleated sheet, or triple helix. 

Soap Soap has been known since antiquity as a surfactant for removal of soil from textiles. Soap is readily made by basic hydrolysis (saponification) of animal fats (fatty esters of glycerol). Soap is the resultant sodium sal t of the fatty acids, with the composition depending on the source of fatty acid esters. Soap suffers from one major deficiency as a surfactant in hard water containing calcium and magnesium cations, the sodium ion in soap is replaced by these multivalent ions to form insoluble salts which caimot act effectively as surfactants. 

The glycerol may be united to three molecules of the same acid, or three molecules of different acids, the latter constituting a mixed glyceride. Hydrolysis may be accomplished by enzymes, such as the lipases of the alimentrary tract, by alkalies, or by superheated steam. Alkaline hydrolysis of a fat is termed saponification, because the alkali combines with the liberated aliphatic acid to form a soap. 

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