Fundamentals Used During The Chemical Process Of Making Soap

• Soaps are produced during the chemical reaction known as saponification.

• Saponification is the reaction between a fat or oil and a base, producing glycerol and a salt (soap) fat or oil + base -----> glycerol + salt (soap)

• Soaps are usually sodium or potassium salts of long-chain fatty acids

• Soaps are cleaning agents or detergents.

• Molecules of soap are made up of two parts: a non-polar, hydrophobic tail consisting of a long hydrocarbon chain a hydrophilic, negatively charged, carboxylate ion (anion) head

• Hydrophobic: aversion to water, not readily wettable by water. Hydrophilic: affinity for water, wettable by water

• Saponification fat or oil

(ester) + base heat

-----> glycerol

(alkanol) + salt

(soap)

RCOOR' + NaOH heat

The main sources of fats are beef and mutton tallow, while palm, coconut and palm kernel oils are the principal oils used in soapmaking. The raw materials may be pretreated to remove impurities and to achieve the color, odor and performance features desired in the finished bar. The chemical processes for making soap, i.e., saponification of fats and oils and neutralization of fatty acids.

Both continuous and batch processes produce soap in liquid form, called neat soap, and a valuable by-product, glycerine (1). The glycerine is recovered by chemical treatment, followed by evaporation and refining. Refined glycerine is an important industrial material used in foods, cosmetics, drugs and many other products.

The next processing step after saponification or neutralization is drying. Vacuum spray drying is used to convert the neat soap into dry soap pellets (2). The moisture content of the pellets will vary depending on the desired properties of the soap

There are many types of triglycerides; each type consists of its own particular combination of fatty acids.

Fatty acids are the components of fats and oils that are used in making soap. They are weak acids composed of two parts:

A carboxylic acid group consisting of one hydrogen (H) atom, two oxygen (O) atoms, and one carbon (C) atom, plus a hydrocarbon chain attached to the carboxylic acid group. Generally, it is made up of a long straight chain of carbon (C) atoms each carrying two hydrogen (H) atoms.

Alkali

An alkali is a soluble salt of an alkali metal like sodium or potassium. Originally, the alkalis used in soapmaking were obtained from the ashes of plants, but they are now made commercially. Today, the term alkali describes a substance that chemically is a base (the opposite of an acid) and that reacts with and neutralizes an acid.

The common alkalis used in soapmaking are sodium hydroxide (NaOH), also called caustic soda; and potassiumhydroxide (KOH), also called caustic potash.

How Soaps are Made

Saponification of fats and oils is the most widely used soapmaking process. This method involves heating fats and oils and reacting them with a liquid alkali to produce soap and water (neat soap) plus