Soaps and Detergents

Soaps and detergent

By

Muhammad Sajid Majeed

Applied chemistry GCUF

.

   Soap got its name, according to an ancient Roman legend, from Mount Sapo, where animals were sacrificed. Rain washed a 

mixture of melted animal fat, or tallow, and wood ashes down into the clay soil along the Tiber River. Women found that this clay mixture made their wash cleaner with much less effort.

   As Roman civilization advanced, so did bathing. The first of the famous Roman baths, supplied with water from their aqueducts, was built about 312 B.C. The baths were luxurious, and bathing became very popular. By the second century A.D., the Greek physician, Galen, recommended soap for both medicinal and 

cleansing purpose 

The early Greeks bathed for aesthetic reasons and apparently did not use soap. Instead, they cleaned their bodies with blocks of clay, sand, pumice and ashes, then anointed themselves with oil, and scraped off the oil and dirt with a

metal instrument known as a strigil.

What is a Soap?

A soap is compound of alkali and fat, used with water as a cleaning agent

Examples of Soaps

.Sodium stearate (Chemical formula: C17H35COO-Na+)

Sodium palmitate (Chemical formula: C15H31COO-Na+)

Sodium oleate (Chemical formula: C17H33COO-Na+)

What is it made of?

Saponification is the process by which soap is made. Soaps are made from the alkaline of natural esters as fats and oils. These esters are made from large carboxylic acid molecules containing more than ten carbon atoms in their hydrocarbon chains, and glycerol - an alcohol containing 3 OH groups in its molecule.

Soap Manufacturing

Soaps are the product of the reaction between a fat and sodium hydroxide:

Advantages of the soap

Soaps are cheap.

Can be manufactured from renewable sources

Don’t cause skin allergies.

Soaps are biodegradable and so will not perish in the environment.

Disadvantages of the soap They do not remove all types of

dirt.

They don’t clean very efficiently in hard water. Hard water contains calcium and magnesium ions that react with the soap to form insoluble salts called scum.

They form gels which clog sewerage systems.

Detergents

What is a detergent?

A detergent is a cleaning agent. There are two types of detergents:

soapy detergent [made from the hydrolysis of natural esters] and the soapless detergent.

What is it made of?

In general detergents are made from hydrocarbon products which react with highly concentrated sulphuric acid to convert them to an organic acid based on the –SO3H group.

Examples of Detergent

Two basic examples of well-known detergents

of the sulphonate group  or the sulphate

group   are:

Soapy and SOAPLESS DETERGENTS

Soapless Detergents

Soapy Detergents

Made from petroleum products that have been treated with concentrated sulphuric acid.

Most are non- biodegradable and comes in the liquid form.

Soapy detergents are made from reacting natural esters with an alkali.

Usually comes in the form of bars and is biodegradable.

It is converted to scum when used with hard water.

What is found in a detergent?

Detergents does not contain 100% active detergent ingredients.

Detergents usually contains 20% surfactant which is the active cleaning ingredient. 30% phosphates which is added to soften hard water. 40% sodium sulphate for keeping it dry and10% bleaching agents and optical brighteners.

Advantages of the detergent

They are very cheap.

There is no wastage when using hard water since detergents doesn’t form scum.

Disadvantages of the detergent It is non- biodegradable which

means that it is resistant to bacterial breakdown and if it ends up in rivers or lakes cause foaming.

Prone to extensive algal growth due to the high phosphate content which provides nutrients for the algal.

DIFFERENCES BETWEEN SOAPS AND DETERGENTS

SOAPS

They are metal salts of long chain higher fatty acids. These are prepared from vegetable oils and animal fats. They cannot be used effectively in hard water as they produce scum i.e., insoluble precipitates of Ca2+, Mg2+, Fe2+ etc.

DETERGENTS

These are sodium salts of long chain hydrocarbons like alkyl sulphates or alkyl benzene sulphonates.

They are prepared from hydrocarbons of petroleum or coal.

These do not produce insoluble precipitates in hard water. They are effective in soft, hard or salt water.

Good Bye!