SOAP AND DETERGENT

ByEvelyn, Fatin, Izati

Soaps

Detergent

Environmental Issues

SOAP AND DETERGENT

SOAPSRaw Material

Manufacturing Process

Types Of Soaps

Hydrophobic and Hydrophilic Orientation

What Is Soap????

• Soap is a cleansing agent created by the chemical reaction of a fatty acid with an alkali metal hydroxide.

• water-soluble sodium or potassium salts of fatty acids• made from fats and oils, or their fatty acids, by treating

them chemically with a strong alkali• has the general chemical formula RCOOX.

Main materials are caustic soda or sodium hydroxide or potassium hydroxide

Animal fats Plant oils (Coconut oil, Palm oil) Others common material are olive oil and cottonseed

oil

Raw Material

Manufacturing Process

Oil Preparation Saponification

WashingFittingDrying

Oil Preparation

Tallow and coconut oil are blended together and dried in a vacuum chamber.

Once the oils are dry, bleaching earth is added to remove any colored impurities. The bleaching earth remove by filtration.

The oils are stored ready for saponification.

Saponification

The bleached oils is mixed with recycled spent lye and fresh caustic soda (NaOH).

The mixture is boiled until it settles into two layers of soap (bottom) and unreacted oil (top).

Washing

The crude soap is washed with fresh caustic solution and nigre lye.

The washed soap is sent to fitting pans.

Fitting

Remaining unwanted glycerine is removed by reboilling with water, NaCI and a small amount of NaOH solution.

The electrolyte concentration in the water separates the soap and water into two layer.

The top layer is neat wet soap and pumped off to be dried.

The neat soap may be extracted for conventional soap productio( bar, flake or powder).

The bottom layer is known as nigre layer consists of solution os soap, glycerine and NaCI.

Drying

The water level is reduced down to about 12% by heating the soap to about 125 C under pressure and vacuum pressure of about 40 mm Hg (5.3 kPa).

the soap then mixed with air in a heat exchangerm where the soap is cooled to 45 C.

The soap then blended together with fragrance, colorants and all other ingredients.

The saponification of triglycerides with an alkali is a bimolecular nucleophilic substitution (SN2).

The rate of the of the reaction depends on the increase of the reaction temperature and on the high mixing during the processing

Saponification equation:NaOH + C17H35COOH → C17H35COONa + H2O

Types Of Soaps

Two main important classes of soaps are toilet and industrial.

Toilet soap is usually made from mixture of tallow and coconut in ratios 80-90/10-20.

The bar soap includes regular and super fatted toilet soaps, deodorant and antimicrobial soaps and hard water soaps.

The super fatted soaps are also made from mixture of coconut oil in ratios 50-60/40-50.

Hydrophobic and Hydrophilic Orientation

A soap molecule has two ends with different properties:

A long hydrocarbon part which is hydrophobic (i.e. it dissolves in hydrocarbon).

A short ionic part containing COO-Na+ which is hydrophilic (i.e. it dissolves in water).

Mechanism Of Soap

SOAP

Advantages Disadvantages

• Very effective as a bactericide

• It will form gels, emulsify oil and lower the surfaces tension of water.

• Excellent everyday cleaning agent.

• Good biodegradability

• Oils and perfume are immiscible in water and if spilled create havoc, although the oils do solidify at room temperature.

• When used in hard water, soap can produced a scum.

**Soaps, will react with metal ions in the water and can form insoluble precipitates (soap scum).

Detergent

Detergent- product that after formulation is devised to promote the development of detergency.

Three major components of raw material of detergent: Surfactants Builders Bleaching agents

Classification of surfactants

Surfactants are water-soluble oil-insoluble (hydrophilic) portion on one side and an oil-soluble water-insoluble (hydrophobic) portion on the opposite side.

The surfactants exhibits surface activity by lowering the surface tension of liquids.

surfactants are classified by their ionic (electrical charge) properties in water: Anionic (negative charge) Cationic (positive charge) Nonionic (no charge) Amphoteric ( either positive or negative charge)

Anionic surfactants

Anionic surfactants are compounds in which the detergency is realized in the anion.

Few examples are alkylbenzene suphonates, fatty alcohol sulphates (alkyl sulphates) and alkyl ether sulphates.

R-SO3- Na+

Linear alkyl benzene sulphonate (LAS)

It has good foaming ability and its foam can be readily stabilized

Its foam can be boosted or controlled by foam inhibitors/regulators.

LAS is sensitive to water hardness.

Fatty alcohol sulphates (ROSO3H)

They are readily biodegradable. Used in heavy and light duty detergents as well

as in toilet soaps. They are chemically stable on the alkaline side

and are easily hydrolysed on the acid side.

Alkyl ether sulphates (AES)

They are highly foaming and have low sensitivity to water hardness. High solubility Good storage stability at low temperature

AES are suitable components of detergents for delicate or wool washables, foam baths, hair shampoos and dishwashing liquids.

Nonionic surfactants The majority of nonionic surfactants are condensation

products of ethylene oxide with hydrophobe. Hydrophobe is a high molecular weight material with

an active hydrogen atom. The nonionic material can be one of the reaction

products. Fatty alcohol and alkylphenol condensates Fatty acid condensates Condensates of ethylene oxide with an amine Condensates of ethylene oxide with an amide

Alkyl polyglycol ethers (AEO)

Obtained by ethoxylation of ethylene oxide and any compound having reaction hydrogen atoms (hydrophobe).

The polyglycol ethers of straight chain alcohols are becoming the most important surfactants.

Most of AEO are viscous liquids or soft pastes. Aqueous solution exhibit an inverse solubility

behaviour. ( the solubility decreases with increasing temperature)

Alkylolamides of fatty acids

They have a structure of diethanolethamide and monoethanolamide.

Monoethanolamide are usually used in laundry detergents.

Diethanolethamide are used in light duty and dishwashing detergents and shampoos.

Their major function is in foam boosting and soil suspension.

Cationic surfactants

These surfactants are very strongly absorbed to the surface of natural fibers, such as cotton, wool and linen.

They are invariably contain amino compounds. They are used for special effects for example as

antistatic agents, fabric softening and as microbicides.

Quaternary ammonium compounds

Commonly used as fabric/textile softener for both household and industrial use.

Amphoteric These surfactants have the characteristics of both

anionic detergents and cationic fabric softeners It show the properties of anionics at high pH and

cationics at low pH. They are used to overcome problems associated with

high electrolyte levels and corrosion. Other properties:

Excellent foaming and lime soap dispersing properties Antistatic Textile softening

For example Alkyl aminopropionic acids have antistatic and

hair softening properties. N-alkylbetains are rarely used because they are

expensive.

Builders

They are used to support detergent action and to deal with the problem of water hardness.

Common builders used are: Alkalis Complexing agents Ion exchangers

Bleaching agents

Hydrogen peroxide is the main bleaching agent Sodium perborate is incorporated in detergents as a

source of hydrogen peroxide It increase the reflectance of visible light at the

expense of absorption. It involves the removal; or change of dyes and soil

by mechanical and/or physical means.

Functions of detergent

As a wetting agent

• Water has high surface tension.• It reduces the surface tension of water.• As a result of this, water spread over the surface and

wets it more easily.

As an emulsifying agent

A detergent increases the wetting power of water. Tap water does not wet this piece of cloth easily, but detergent solution does.

An oil-water emulsion is unstable on standing. Tiny oil droplets rapidly join together and grow

larger to form separate oily layer again.

An oil-water emulsion is stabilized by a detergent.

a) Before the mixture is shakenb) After shakingc) Negatively charged oil droplet repel each other.

DETERGENT

Advantages Disadvantages

• biodegradable• do not decompose in acidic medium.• As detergents are derived from

petroleum they save on natural vegetable oils.

• can lather well even in hard water*

• Their elimination from municipal wastewaters by the usual treatments is a problem.

• have a tendency to produce stable foams in rivers that extend over several hundred meters of the river water.

• danger to aquatic life.• Some surfactants are incompletely

broken down with conventional treatment processes

• inhibit oxidation*

Environmental Issue

Emissions and control The exhaust air from detergent towers

contains two types of contaminants Fine detergent particles Organics vaporized in the higher zone

The amount of foam on river was increasing and where

water was being drawn from wells located close to

household discharge points, the water tend to form when

coming out of the tap.

In certain lake and ponds algae started reproducing at an

unprecedented rate. This was blamed on the extensive use

of phosphate in the form of sodium tripolyphosphate.

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