chemistry of detergents

1. Chemistry of Detergents
Presented by Taskeen Rubab
28145
General chemistry
Dr. Ammara Fatima

2. Introduction
A detergent is a surfactant or
mixture of surfactants with
purifying properties in dilute
solutions. In the domestic context,
the term detergent itself refers
specifically to laundry detergent
or dish detergent, as opposed to
hand soap or other types of
cleaning agents.

3. Detergents
• Detergents are the sodium salt of long chain
benzene sulphuric acids
• Detergents are primarily surfactants, which
could be produced easily from
petrochemicals
• Surfactants lower the surface tension of
water, essentially making it wetter so that
that it is less likely to stick to itself and more
likely to interact with oil and grease
• The ionic group is in detergent is SO2Na

4. Chemical composition
Hydrophobic part Hydrophilic part
• Non-polar
• Water repelling part
• Consisting of long h structure
• hydrocarbons or ring
• Forming the tail of the detergent
• Polar
• Water-attracting part
• Which consisting of small ionic group
such as sulphonates, sulphates etc
• Forming the head of the head of the
detergent

5. Examples of detergents
Two basic examples of well-known detergents of the sulphonate group
or the sulphate group are
• Sodium p-dodecyl benzene sulphonate
• Sodium lauryl sulphate or sodium n-dodecyl sulphate

6. Chemical categories for detergents
Depending on the electric charge of
the surfactants, detergents
are classified into three broad
groupings.
• Anionic detergents
• Cationic detergents
• Non-ionic and zwitter ionic
detergents

7. Cationic detergents
• Cationic detergents are similar to thje anionicones, with a
hydrophobic co,mponent, but, instead of the anionic sulfonates
group,
• the cationic surfactants have quartnery ammonium as the polar end.
• The ammonium center is positively charged
• The most common is Acetyl trimethyl ammonium bromide

8. Anionic Detergents
• The detergents which consist negative ionic are
called anioc detergents
• The majority are alkyl sulfates and others are
generally known as alkyl benzene sulfonates

9. Non-ionic and zwitter ionic detergents
• Zwitterionic detergents possess a net zero charge arising from the
presence of equal numbers of + 1 and chemical groups
• Examples include CHAPS
• (3-[(3cholamidopropyl)dimethylammonio]1-propanesulfonate)

10. Ingredients
• Surfactants
• Acids
• Alkalis
• Plasticizers
• Binders
• Water
• Enzymes
• Fragrance causing agents
• Bleaches
• Dyes and pigments

11. Chemical reaction
• Preparation of detergent

12. How do detergents work
Soaps and detergents are made from long molecules that have a head and
tail. These molecules are called tensioactives; a surfactant molecule is
described in the diagram below. The head of the molecule is drawn to water
(hydrophilic) and grease and dirt attract the tail (hydrophobic).

13. Industrial preparation
Powder detergents are produced by
• Spray drying process
• Agglomeration process
• Dry mixing process

14. Hard water and its effect on detergents
• Hard water contains dissolved calcium and magnesium compounds
such as:
oMagnesium hydrogen carbonate
oCalcium hydrogen carbonate
oMagnesium sulfate
oCalcium sulfate
• Detergent molecules have a long chain of carbon and hydrogen
atoms,but at the end of the molecule there is this group SO3 called
sulphonate, so hard water does not effect its cleaning action because
they are soluble in hard water and do not form scum

15. Advantages of Detergents
• Since detergents are the salts of strong acids they do not decompose
in acidic medium
• Thus detergents can effectively clean fabric even if the water is acidic
• Synthetic detergents are more soluble in water than soaps
• They have a stronger cleansing action than soaps
• As detergents are derived from petroleum they save on natural
vegetable oils, which are important as essential cooking medium

16. Disadvantages of detergents
• Many detergents are resistant to action of the action of biological
agents and thus are not biodegradable. Their elimination from
municipal wastewaters by the usual treatments is a problem
• They have a tendency to produce stable foams in rivers that extend
over several hundred meters of the river water.
• This is due to effects of surfactants used in their preparation. Thus
they pose a danger to aquatic life
• They tend to inhibit oxidation of organic substances present in
wastewaters because they form a sort of envelop around them