Sodium, stearate

Sodium stearate is one of the main compounds in common soap. To make soap, you start with beef fat. If you treat beef fat with steam you get tallow, a mixture of fats, one of which is glyceryl tristearate  

When you boil glyceryl tristearate in lye (sodium hydroxide), you get sodium stearate and glycerin. When you remove the glycerin, you get soap. 

The sodium end of the molecule attracts water. The long hydrocarbon chain at the other end attracts oils and fats. 

Soap works by helping to break fat and oil droplets into small pieces. The pieces are coated with the soap, with the hydrocarbon chains attached to the fat, leaving the sodium ends dangling in the water. The oils are now completely surrounded by water, instead of being attached to skin or clothing, and so they rinse away easily. 

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Results can sometimes be unexpected. The first study of this type made use of labeled Aerosol OTN [111], an anionic surfactant, also known as di-n-octylsodium sulfosuccinate. The measured F was twice that in Eq. III-93 and it was realized that hydrolysis had occurred, that is, X + H2O = HX + OH , and that it was the undissociated acid HX that was surface-active. Since pH was essentially constant, the activity of HX was just proportional to C. A similar behavior was found for aqueous sodium stearate [112]. 

Polymerization takes place, in the following manner in the presence of suitable peroxide catalyst these compounds polymerize with themselves (homopolymerizatiOn) in aqueous emulsion. When the reaction is complete, the emulsified polymer may be used directly or the emulsion coagulated to yield the solid polymer (312). A typical polymerization mixture is total monomer (2-vinylthiazole), 100 sodium stearate, 5 potassium persulfate, 0.3 laurylmercaptan, 0.4 to 0.7 and water, 200 parts. 

The solubility behavior of salts of carboxylic acids having 12—18 carbons is unusual and can be illustrated by considering sodium stearate (sodium octadecanoate) As seen by the structural formula of its sodium salt... 

FIGURE 19 5 Electrostatic potential map of sodium stearate Most of the molecule is comprised of a nonpolar hydrocarbon chain (green) One end is very polar as indicated by the red and blue associated with the carboxylate and sodium ions respectively... 

Compare the electro r-static potential maps of sodium lauryl sul 5 fate and sodium stearate on Learning By Modeling... 

Carboxylate groups are hydrophilic ( water loving ) and tend to confer water sol ubility on species that contain them Long hydrocarbon chains are lipophilic ( fat loving ) and tend to associate with other hydrocarbon chains Sodium stearate is an example of an amphiphilic substance both hydrophilic and lipophilic groups occur within the same molecule... 

The formation of micelles and their properties are responsible for the cleansing action of soaps Water that contains sodium stearate removes grease by enclosing it m the hydrocarbon like interior of the micelles The grease is washed away with the water not because it dissolves m the water but because it dissolves m the micelles that are dis persed m the water Sodium stearate is an example of a soap sodium and potassium salts of other C12-C1S unbranched carboxylic acids possess similar properties... 

Inorganic salts are also used to promote shampoo thickening. These should be used sparingly since an excess may have a deleterious effect on a product s physical stabiHty. Sodium chloride commonly is used in these cases. The additions of sodium stearate and stearic amides can be found in paste shampoos for thickening. 

Monohydroxyaluminum distearate, (HO)Al(OOC(CH2) gCH2)2, used to be the largest selling aluminum carboxylate (1). Although stiU sold, the product is no longer Hsted in the U.S. International Trade Commission Report (1) because of low volume or confidentiahty constraints because of too few supphers. Aluminum distearate is a white powder that is insoluble in water, alcohol, and ether. A key property is its abiUty to gel vegetable oils and hydrocarbons. Aluminum distearate is prepared by the reaction of aqueous sodium stearate with aqueous aluminum sulfate or chloride at pH 7.3. Aluminum monostearate is formed if the sodium stearate solution is held at pH 9.5 (44). 

Deodorant and cologne sticks are formed by allowing sodium stearate to gel in a suitable organic solvent, usually ethanol or propylene glycol. The soap and the solvent are heated under reflux until the soap is dissolved. The solution is cooled to about 60°C fragrance, color, and the like are added and the mass is placed into suitable containers. 

Fatty-acid soaps Alkali, alkaline earth, and other metal soaps sodium stearate aluminum stearate Gear oils paper stock paper sizing glue solutions... 

Stearate ion contains two very different str-uctural units—a long nonpolar- hydrocarbon chain and a polar- carboxylate group. The electrostatic potential map of sodium stearate in Figure 19.5 illustrates how different most of the molecule is from its polar- carboxyl-ate end. 

Water is extensively used to produce emulsion polymers with a sodium stearate emulsifrer. The emulsion concentration should allow micelles of large surface areas to form. The micelles absorb the monomer molecules activated by an initiator (such as a sulfate ion radical 80 4 ). X-ray and light scattering techniques show that the micelles start to increase in size by absorbing the macromolecules. For example, in the free radical polymerization of styrene, the micelles increased to 250 times their original size. 

Sodium bicarbonate, 112-113 Sodium carbonate, 61 Sodium chloride 44q common ion effect and, 439 electrolysis, 499 formation, 3 structure, 36 Sodium chlorine, 4 Sodium hydroxide, 61,84,441 Sodium hypochlorite, 369-370 Sodium stearate, 595 Sodium vapor lamps, 135 Solids... 

The metal salts of natural carboxylic acids, like sodium stearate, are called soaps. 

Sodium hypochlorite, 360 Sodium myristate, 426 Sodium stearate, 426 Sodium uranyl acetate, 17.)... 

A cationic surfactant will often have an ammonium group attached to a halogen, as in the ammonium chloride mentioned above. Anionic surfactants, such as soap, often have a sodium, potassium, or ammonium group, as in sodium stearate. 

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