What is the procedure of manufacturing soap on small scale?

Answer 1

Synthesis of Soap (Saponification) Soap in various forms has been around for centuries. Plants that contain saponins (chemicals that produce a soap-like lather) were used for many years before soap-making methods were discovered. Until the middle of the nineteenth century, use of soap was sporadic at best—with some cultures being much more interested in cleanliness than others. Soap commonly consists of the sodium or potassium salt of long-chain organic fatty acids such as sodium stearate. This salt is normally more soluble in an aqueous solution than is stearic acid (most salts are more soluble than their “parent” compound). A large hydrocarbon portion of the molecule allows the soap to accomplish its special cleaning function. The inorganic ionic end of the salt remains soluble in the aqueous solution while the long hydrocarbon portion becomes embedded in the grease or dirt that you are trying to remove. These organic portions form a micelle around the grease or dirt and allow it to be lifted out and washed away. Soap can be synthesized by heating the esters of fatty acids in a basic solution. Pioneer women accomplished this by heating animal fats with the potassium hydroxide that they obtained from wood ashes. The soap that was formed this way would float to the top and solidify and it would leave glycerol in the bottom of the kettle (glycerol is similar to glycerin). Use of a natural soap (like the one that you are about to synthesize) can result in some problems when it comes to general cleaning. Soap molecules will form an insoluble precipitate in the presence of the calcium, magnesium, and iron ions that are found in hard water. Also, in acidic solutions, the soap molecules can be converted into free fatty acids, which do not have any cleaning ability. Because of these problems, most of the “cleaning” that is now done is done with synthetic detergents that can be designed to avoid the problems that are present with “soap”. Safety Precautions: Sodium hydroxide is a highly corrosive base. Contact with skin will cause irritation and burning. Place excess in appropriate labeled waste container in hood after use. Ethanol is flammable and also toxic. Prolonged exposure to vapors can cause headaches. Place excess in appropriate labeled waste container in hood after use. The filtrate from this experiment should be disposed in appropriate labeled waste container in hood after use. Procedure: Dissolve 10 grams of sodium hydroxide in 20 ml. of deionized water. After the sodium hydroxide is completely dissolved, add 20 ml. of 95% ethanol. After placing 10 grams of fat into a 250 ml beaker, add the solution of sodium hydroxide, ethanol, and water to the 250 ml. beaker. Heat the mixture carefully on a hot plate for approximately thirty minutes. Keep another 40 ml of the ethanol/water mixture ready in case the solution begins to foam. If the solution begins foaming, add small amounts of the ethanol/water mixture to stop the foaming. Add 50 grams of salt (sodium chloride) to 150 ml. of water in a 400 ml. beaker. Quickly pour the saponification mixture (fat and alcohol) into the sodium chloride solution. Stir and cool to room temperature. Filter and air dry. Weigh the final product and record its appearance. Source: sitemaker.umich.edu/chemistry.ion/files/exp5_soap.doc

Answer 2

saponification