Detergent

DETERGENTS Surfactants are one of the major
components of cleaning products and can
Detergents are composed of physical or be regarded as the 'workhorses': they do
chemical active ingredients such as the basic work of breaking up soils and
surfactants, builders, solvents, chelators, keeping the dirt in the water solution to
preservatives, bleaches and enzymes. prevent re-deposition of the dirt onto the
surface from which it has just been
1. Surfactants removed. Surfactants disperse dirt that
2. Chelating/Sequestering Agents normally does not dissolve in water.
3. Builders
4. Solvents Each surfactant molecule has a hydrophilic
5. Preservatives (water-loving) head that is attracted to
6. Bleaches water molecules and a hydrophobic (water-
7. Enzymes hating) tail that repels water and
simultaneously attaches itself to oil and
1. Surfactants grease in dirt. These opposing forces
loosen the dirt and suspend it in the water.
The interaction between water, surfactant,
and surface is called “surface activity.” In
fact, the name surfactant comes from the
phrase “SURFace ACTive AgeNT.”

Surfactants are molecules that reduce the
surface tension of water, helping it to
spread out more uniformly. Basically,
surfactants make water “wetter”. They
also help penetrate, loosen and trap soils .

In more technical terms:

 Surfactants enable the cleaning
solution to fully wet the surface being
cleaned so that dirt can be readily
loosened and removed.

 Surfactants clean greasy, oily, Modern technology can produce many
particulate-based, protein-based, and different types of surfactants by changing
carbohydrate-based stains. the chemical composition of the
hydrophobic and hydrophillic ends of the
 Surfactants are instrumental in molecule. By changing the chemical
removing dirt and in keeping them composition, surfactants have greater or
emulsified, suspended, and dispersed lesser abilities in different areas:
so they don't settle back onto the
surface being cleaned. a. Detergency: the ability to break the bond
between soil and the surface.

Compiled by Deniz Kaya -1-

b. Penetrating and wetting: allows water to the surfactants surround it until it is
surround soil particles that would dislodged from the boundary. Notice in
otherwise repel the water. diagram 4 that the dirt molecules are
actually suspended in solution.
c. Foaming: creation of bubbles that lift
dirt from the surface.

d. Emulsifying: the ability to break up
greasy petroleum soils into small droplets
that can be dispersed thoroughly.

e. Solubilizing: dissolving a soil so that it
is no longer a solid soil particle.

f. Dispersing: spreading the minute soil
particles throughout the solution - to
prevent them back onto the cleaned
surface.

Many surfactants will be used in
combination to create a cleaner/detergent
with just the right balance of detergency,
foaming, wetting, emulsifying, solubilizing
and dispersing properties. Each surfactant
contributes its own special abilities to the
cleaner formula.

Surfactants can be natural or synthetic
origin. Surfactants from natural origin
(vegetable or animal) are known as oleo-
chemicals and are derived from sources
such as palm oil or tallow. Surfactants
from synthetic origin are known as petro-
chemicals and are derived from petroleum.
Formulation scientists focus quite a lot on
developing detergents that perform well at
lower wash temperatures. This approach
will continue to yield energy savings
during the consumer use phase, hence a
reduction of CO2 emissions.

The surfactant lines up at the interface. The
hydrophobic end of the molecule gets
away from the water and the hydrophilic
end stays next to the water. When dirt or
grease is present (hydrophobic in nature)


The law of mass cleaning action expresses water with the positively charged water
a relationship between time, action, hardness ions (calcium and magnesium) ,
concentration, and temperature in the which can lead to partial deactivation. The
process of removing soils. This laws states more calcium and magnesium molecules in
that if you decrease any one of these the water, the more the anionic surfactant
factors, we must increase one or more of system suffers from deactivation. To
the remaining factors in order to maintain prevent this, the anionic surfactants need
equal cleaning ability. help from other ingredients such as
builders (Ca/Mg sequestrants) and more
detergent should be dosed in hard water.

The most commonly used anionic
surfactants are alkyl sulphates (AS), alkyl
ethoxylate sulphates (AESs) and soaps.

LAS (Linear Alkylbenzyne Sulphonate)

O
O
CH 3 (CH 2 ) 11 S
Na
O
LABSA (Linear Alkylbenzene Sulphonic
Acid)
SO3
There is a broad range of different o
surfactant types, each with unique
properties and characteristics. Detergents
use a combination of various surfactants to
provide the best possible cleaning results.
There are four main types of surfactants
used in cleaning products. Depending on
the type of the charge of the head, a
surfactant belongs to the anionic, cationic,
non-ionic or amphoteric/zwitterionic
family.
Anionic surfactants

In solution, the head is negatively charged.
This is the most widely used type of
surfactant for laundering, dishwashing Cationic surfactants
liquids and shampoos.
In solution, the head is positively charged.
Anionic surfactants are particularly There are 3 different categories of
effective at oily soil cleaning and oil/clay cationics each with their specific
soil suspension. They can react in the wash application:


1. In fabric softeners and in detergents with 3. In household and bathroom cleaners,
built-in fabric softener, cationic surfactants cationic surfactants contribute to the
provide softness. Their main use in laundry disinfecting/sanitizing properties.
products is in rinse added fabric softeners,
such as esterquats (esterified quaternary Non-ionic surfactants
ammonium compounds), one of the most
widely used cationic surfactants in rinse These surfactants do not have an electrical
added fabric softeners. charge, which makes them resistant to
water hardness deactivation. They are
An example of cationic surfactants is the excellent grease removers that are used in
esterquat. laundry products, household cleaners and
hand dishwashing liquids.

Nonionic surfactants , which do not
dissociate when dissolved in water, have
the broadest range of properties depending
upon the ratio of hydrophilic/ hydrophobic
balance. This balance is also affected by
2. In laundry detergents, cationic temperature. For example, the foaming
surfactants (positive charge) improve the properties of nonionic detergents is
packing of anionic surfactant molecules affected by temperature of solution. As
(negative charge) at the stain/water temperature increases, the hydrophobic
interface. This helps to reduce the character and solubility decreases. At the
dirtl/water interfacial tension in a very cloud point (minimum solubility), these
efficient way, leading to a more robust dirt surfactants generally act as defoamers,
removal system. They are especially while below the cloud point they are varied
efficient at removing greasy stains. in their foaming properties.

An example of a cationic surfactant used in Most laundry detergents contain both non-
this category is the mono alkyl quaternary ionic and anionic surfactants as they
system. complement each other's cleaning action.
Non-ionic surfactants contribute to making
the surfactant system less hardness
sensitive.

The most commonly used non-ionic
surfactants are ethers of fatty alcohols

CTAB (Cetyl Trimethyl Ammonium Bromide)

CH 3

CH 3
N Cl
CH 3 (CH 2 ) 15 CH 3


NPE (Nonyl Phenol (Poly)Ethoxylate) Dodecyl Dimethyl Sulphobetaine

CH 3
H 2 O
CH 3 (CH 2 ) 8 O(CH 2 CH 2 O) m H C
N
S
CH 3 (CH 2 ) 11 O
CH 3
O

Amphoteric/zwitterionic surfactants
Dodecyl Dimethyl Amine Oxide
These surfactants are very mild, making
CH 3 CH 3
them particularly suited for use in personal
care and household cleaning products. N
OH
H
O
N
They can be anionic (negatively charged), CH 3 (CH 2 )11 CH 3 CH 3 (CH 2 ) 11 CH 3
cationic (positively charged) or non-ionic
(no charge) in solution, depending on the
acidity or pH of the water. They behave as It is a common practice to blend surfactant
cationic surfactants under acid conditions, ingredients to optimize their properties.
and as anionic surfactants under alkaline However, because of precipitation
conditions. problems, cationic and anionic surfactants
cannot be blended.
They are compatible with all other classes
of surfactants and are soluble and effective 2.Chelating/Sequestering Agents
in the presence of high concentrations of
electrolytes, acids and alkalis. Soil removal is a complex process that is
much more involved than just adding soap
These surfactants may contain two charged or surfactant to water. One of the major
groups of different sign. Whereas the concerns we have in dealing with cleaning
positive charge is almost always compounds is water hardness. Water is
ammonium, the source of the negative made "hard" by the presence of calcium,
charge may vary (carboxylate, sulphate, magnesium, iron and manganese metal
sulphonate). These surfactants have ions. These metal ions interfere with the
excellent dermatological properties. They cleaning ability of detergents. The metal
are frequently used in shampoos and other ions act like dirt and "use up" the
cosmetic products, and also in hand surfactants, making them unavailable to act
dishwashing liquids because of their high on the surface we want to clean.
foaming properties.
A chelating agent (pronounced keelating
from the Greek word claw) combines itself
with these disruptive metal ions in the
water. The metal ions are surrounded by
the claw-like chelating agent which alters
the electronic charge of the metal ions
from positive to negative (see diagram
below.) This makes it impossible for the
metal ions to be precipitated with the
surfactants. Thus, chelated metal ions
remain tied up in solution in a harmless


state where they will not use up the Precipitation - removing metal ions from
surfactants. solution as insoluble materials.

Builders, in addition to softening, provide
a desirable level of alkalinity (increase
pH), which aids in cleaning. They also act
as buffers to maintain proper alkalinity in
wash water.

Finally, builders help emulsify oily and
greasy soil by breaking it up into tiny
globules. Many builders will actually
Some common chelating agents used in peptize or suspend loosened dirt and keep
industrial cleaning compounds include it from settling back on the cleaned
phosphates, EDTA (ethylene diamine tetra surface. Below are three of the most
acetate), NTA, gluconic acid, sodium common builders used in today's heavy-
citrate, and zeolite compounds. duty detergents. A short description of
each follows.
Organic chelating agents, which are used
in formulation in water conditioners, are
more efficient than are phosphates in
sequestering calcium and magnesium ions EDTA
and in minimizing scale buildup. Most Ethylene Diamine
organic agents are salts of EDTA. Tetra Acetate

3. Builders

The chelating process, though very
effective, is not always necessary and adds
to the cost of formulating detergents. NTA
Builders are often a multifuctional Nitrilo Triacetic Acid
alternative and they are cheaper.

Builders are added to a cleaning compound
to upgrade and protect the cleaning Phosphates, usually sodium
efficiency of the surfactant(s). Builders tripolyphosphate (STPP), have been used
have a number of functions which help to as builders extensively in heavy-duty
reduce the hardness of the water, buffer the industrial detergents. They combine with
solution, and emulsify the soil. hardness minerals to form a soluble
Builders soften water by deactivating complex which is removed with the wash
hardness minerals (metal ions like calcium water. They also sequester dissolved iron
and magnesium. They do this through one and manganese which can interfere with
of two ways: detergency.

Sequestration - holding metal ions in
solution.


Solvents are chemical substances that can
dissolve, suspend, or extract other
materials, usually without chemically
changing either the solvents or the other
Sodium tripolyphosphate materials. Solvents can be organic,
(STPP) Na5P3O10 meaning the solvent contains carbon as
part of its makeup, or inorganic, meaning
Sodium carbonate (soda ash) is used as a the solvent does not contain carbon. For
builder but can only soften water through example, "rubbing" alcohol (isopropyl
precipitation. Precipitated calcium and alcohol) is an organic solvent, and water is
magnesium particles can build up on an inorganic solvent. Hydrocarbon
surfaces, especially clothing, and therefore (aliphatic and aromatic hydrocarbons) and
sodium carbonate is not used in laundry oxygenated solvents (alcohols, glycol
detergents. ethers ketones, esters, and glycol ether
esters) are examples of types of organic
solvents that can effectively dissolve many
materials.

Water is a solvent that dissolves many
things. But water cannot dissolve
Sodium carbonate / Na2CO3 everything. For example, water will not
dissolve oily/greasy substances. That is
Sodium silicate serves as a builder in because solvents work on the principle of
some detergents when used in high “like dissolves like.” Water has chemical
concentrations. When used in lower characteristics that are very different from
concentrations, it inhibits corrosion and greases. In order to dissolve things that
adds crispness to detergent granules. water cannot, other solvents are needed.
Sodium silicate is the common name for a These solvents are chemically much more
compound sodium metasilicate. similar to greases and, therefore, can
effectively dissolve them.

Water makes up a large percentage of most
liquid cleaner formulas. It is not
uncommon for water-based detergents to
contain 50% water or more. Some ready-
Sodium metasilicate / Na2SiO3
to-use formulations may contain as much
as 90% to 95% water.
4. Solvents
Water can be considered an active
Solvents can be found in a wide variety of
ingredient that actually adds to the
applications. Coatings, cleaners, personal
detergency of cleaners. It performs several
care products, inks, adhesives,
very important functions in liquid cleaners.
pharmaceuticals, and agricultural products
Most importantly, it adds to the
all benefit from the performance
"detergency" of a cleaner. Water acts as a
advantages of modern solvents.
solvent that breaks up soil particles after
the surfactants reduce the surface tension


and allow the water to penetrate soil (water
is commonly referred to as “the universal BHT - Butylated
solvent”). hydroxdytoluen
e C15H24O
Water also aids in the suspension and anti-
redeposition of soils. Once the soil has
been dissolved and emulsified away from BHT is a lipophilic (fat-soluble) organic
the surface, we want to prevent it from compound that is primarily used as
being redeposited. Water keeps the soil an antioxidant (E321) . Oxygen reacts
suspended away from the clean surface so preferentially with BHT rather than
that it can be carried away easily during oxidizing fats or oils, thereby protecting
the rinsing process. It is clear that without them from spoilage.
this water, our cleaning formulas would be
much less effective.
Stannic chloride
In addition to water, other chemical pentahydrate
solvents are often added to cleaners to (SnCI4-5H2O)
boost performance. Compounds such as 2-
Butoxyethanol (EGBE), isopropyl alcohol
(rubbing alcohol) and d-Limonene are all
considered solvents. Their main function is Stannic chloride (SnCI4) is a caustic liquid
to liquefy grease and oils or dissolve solid used in soaps as a colour and perfume
soil into very small particles so surfactants stabilizer and bacteria and fungi control.
can more readily perform their function.
In detergents, preservatives are used to
5. Preservatives prevent bacteria from spoiling the solution.
Methyl paraben and propyl paraben are
A preservative is nothing more than a very common for this application.
substance that protects soaps and Detergents would not be preserved if they
detergents against the natural effects of weren't biodegradable. Bacteria found in
aging such as decay, discoloration, air, waste treatment systems and in soil
oxidation and bacterial degradation. decompose the surfactants and other
Synthetic detergents are preserved ingredients found in our cleaners once they
differently from soaps. enter into the environment.

In soaps, preservatives are used to forestall Methyl Paraben
the natural tendency to develop rancidity
and oxidize upon aging. Butylated C8H8O3
hydroxdytoluene (BHT) and stannic
chloride are commonly used in this
application. Also used in small amounts is Propyl Paraben
EDTA.
C10H12O3


Methylparaben and Propylparaben are and others work to kill microorganisms
from the paraben family of chemicals. Due and bacteria. Due to its small size, the
to their antimicrobial properties, the are hypochlorite anion (ClO-) kills bacteria by
used extensively as a water-soluble diffusing through the bacteria's cell wall
preservative in many foods, beverages, and disrupting its ability to function. The
pharmaceuticals, detergents and personal compound attacks lipids in the cell wall,
care products. causing destruction of enzymes and other
parts of the cell, leaving the bacteria
6. Bleaches – Oxidizing Agents harmless . Although bleach can be a useful
disinfectant and stain remover, it is a
A bleach is a chemical that removes colors dangerous chemical that can inflict harm to
or whitens, often via oxidation. Oxidizing human cells the same way it attacks
agents used in detergent application are unwanted bacteria.
sodium hypochlorite (NaClO) (chlorine
bleach) and perborate (oxygen bleach The process of bleaching can be
which contains hydrogen peroxide or a summarized in the following set of
peroxide-releasing compound)
chemical reactions:

Cl2(aq) + H2O(l) H+(aq) + Cl-(aq) +HClO(aq)
Sodium
hypochlorite The H+ ion of the hypochlorous acid then
(NaClO) dissolves into solution, and so the final
result is effectively:
There are several kinds of bleach, but the Cl2(aq) + H2O(l) 2H+(aq) + Cl-(aq) + ClO-(aq)
most widespread form is chlorine bleach,
chemically known as sodium hypochlorite. Hypochlorite tends to decompose into
Bleach eliminates stains because it breaks chloride and a highly reactive form of
apart the bonds of the chromophores in
molecules. Chromophores are the parts of oxygen:
molecules responsible for color. Through ClO- Cl- + O
an oxidation reaction that breaks these
bonds, bleaching makes the compounds This oxygen then reacts with organic
colorless. Therefore, the stain can no
substances to produce bleaching or
longer be seen. A reducing bleach Works
by changing the double bond in antiseptic effects.
chromophores to a single bond, once again 7.Enzymes
making the compounds that cause a stain
colorless. Enzymes are proteins, composed of
hundred of amino-acids, which are
The chlorine in bleach also helps kill produced by living organisms. They are
bacteria because it disrupts their biological responsible for a number of reactions and
processes. When chlorine bleach is added biological activities in plants, animals,
to water, it forms many different human beings and micro-organisms. They
chemicals, one example being are found in the human digestive system to
hypochlorous acid (HOCl). This chemical


break down carbohydrates (sugars), fats or combined effect of surfactants and
proteins present in food. enzymes, stubborn stains can be removed
from fibres.
The most important reasons to use
enzymes in detergents are Lipases

I. that a very small quantity of these Though enzymes can easily digest protein
inexhaustible bio-catalysts can replace stains, oily and fatty stains have always
very large quantity of man made been troublesome to remove. The trend
chemicals towards lower washing temperatures has
made the removal of grease spots an even
II. enzymes can work at very low bigger problem. This applies particularly to
temperature at which traditional materials made up of a blend of cotton and
chemistry quite often is no longer polyester. The lipase is capable of
effective removing fatty stains such as fats, butter,
salad oil, sauces and the tough stains on
III. they are fully biodegradable. All these collars and cuffs.
characteristics make enzymes - on top of
their high efficiency - environmentally Amylases
friendly ingredients.
Amylases are used to remove residues of
Proteases starch-based foods like potatoes, spaghetti,
custards, gravies and chocolate. This type
Proteases are the most widely used of enzyme can be used in laundry
enzymes in the detergent industry. They detergents as well as in dishwashing
remove protein stains such as grass, blood, detergents.
egg and human sweat.

These organic stains have a tendency to Cellulases
adhere strongly to textile fibres. The
proteins act as glues, preventing the water The development of detergent enzymes has
borne detergent systems from removing mainly focused on enzymes capable of
some of the other components of the removing stains. However, a cellulase
soiling, such as pigments and street dirt. enzyme has properties enabling it to
modify the structure of cellulose fibre on
The inefficiency of non enzymatic cotton and cotton blends. When it is added
detergents at removing proteins can result to a detergent, it results into the following
in permanent stains due to oxidation and effects:
denaturing caused by bleaching and
drying. Blood, for example, will leave a Colour brightening: When garments made
rust coloured spot unless it is removed of cotton or cotton blends have been
before bleaching. washed several times, they tend to get a
'fluffy' look and the colours become duller.
Proteases hydrolyse proteins and break This effect is due to the formation of
them down into more soluble polypeptides microfibrils that become partly detached
or free amino acids. As a result of the from the main fibres. The light falling on

Compiled by Deniz Kaya - 10 -

the garment is reflected back to a greater
extent giving the impression that the colour
is duller. These fibrils, however, can be
degraded by the cellulase enzyme,
restoring a smooth surface to the fibre and
restoring the garment to its original colour.

Softening: The enzyme also has a
significant softening effect on the fabric,
probably due to the removal of the
microfibrils.

Soil removal: Some dirt particles are
trapped in the network of microfibrils and
are released when the microfibrils are
removed by the cellulase enzyme.

Compiled by Deniz Kaya - 11 -

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