Soap is produced through a chemical reaction called saponification where triglycerides (fats or oils) are reacted with a strong base like sodium or potassium hydroxide. This produces glycerol and fatty acid salts known as soap. In this experiment, coconut oil was reacted with sodium hydroxide through heating to produce soap. The soap produced was a white solid with a slight pandan smell. Saponification is an exothermic reaction where the internal heat generated supports the process without external heating.

1. INTRODUCTION
Soap is produced by the saponification (hydrolysis) of a triglyceride (fat or oil). (See Figure 1.) In
this process the triglyceride is reacted with a strong base such as sodium or potassium hydroxide
to produce glycerol and fatty acid salts. The salt of the fatty acid is called a soap.
Fatty acids are straight-chain monocarboxylic acids. The most common fatty acids range in size
from 10-20 carbons and most often have an even number of carbon atoms including the carboxyl
group carbon. The carbon-carbon bonds in saturated fatty acids are all single bonds, while
unsaturated fatty acids have one or more carbon-carbon double bonds in their chains. One example
of a saturated fatty acid is palmitic acid, CH3-(CH2)14-CO2H.
Fatty acids are seldom found as free molecules in nature but are most often a part of a larger
molecule called a triglyceride. Triglycerides consist of a three-membered carbon chain (glycerol
backbone) with a fatty acid bonded to each of the three carbon atoms in the glycerol backbone.
The bond between the fatty acid and the glycerol backbone is referred to as an ester linkage. In the
saponification process the ester linkage is broken to form glycerol and soap.
Detergents are similar to soaps in that they have a charged head group and a long nonpolar tail
group, but they are not prepared from natural fats or oils. Detergents are useful because they do
not form precipitates with magnesium or calcium ions, which means that they work in both soft
and hard water.
After detergents started being widely used, it was discovered that they were not broken down in
sewage treatment plants. Many streams and lakes became contaminated with detergents and large
amounts of foam appeared in natural waters. Biodegradable detergents were then developed.
Shown below is an example of a biodegradable detergent, sodium laurylbenzenesulfonate.
Many commercial detergents also contain phosphate compounds. This can be a problem, because
phosphate is a nutrient for plants. Too much phosphate in a pond, lake, or stream accelerates the
growth of algae, which consumes too much of the dissolved oxygen in the water. This disturbs the
ecosystem in the pond, and some organisms will die. Therefore, you will see some detergents these
days that are labeled “phosphate free”. These are better for the environment than phosphate-

2. containing detergents. In this experiment, you will make soap from a fat or an oil by heating it
with sodium hydroxide.
Objectives :
1) Learn how to prepare soap by saponification reaction of NaOH and oils.
2) Understand the condition needed in preparation of soap.
Apparatus and materials :
29.5g NaOH
72mL distilled water
100mL of coconut oil
3mL of pandan leaves extract
Beakers
Stirrer
Spoon
Hot plate
Thermometer
Procedures:
1) NaOH pellets were dissolved 72mL of distilled water (250mL of beaker). Put them aside
and let them cool down in between 27oC to 38oC.
2) After the NaOH solution cooled sufficiently, heat the mixture of coconut oil and 72mL
water in a 500mL beaker, to 82oC. Let oil globules remain suspended in the water until the
next step.
3) Stop heating, drizzle the lye solution into the mixture of oil and water and gently stir to
blend.
4) The beaker was placed back on hot plate and set on to medium heating until the temperature
of the mixture creep back up towards 82oC, continuously stirred but gentle to create the
uniform mixture. Initially the mixture looks like water shimmering with unsaponiafible oil,
but after 10 to 15 minutes it will be gradually become thick and uniform do not allow the
temperature of the soap exceed 82oC or fall below 71oC, the beaker was removed from the
heat occasionally and return to the hot plate as needed.
5) After about 20 minutes, fragrance was added to the hot mixture and stir gently. The mixture
of soap was placed into a mould covered with grease paper and let it cool down.
6) After more than 24 hours or until 2 to 3 weeks, the soap will continue solidify slowly. This
process called ‘curing’.
Results:
Condition Observation
Colour White
Smell Slightly pandan smell
State Solid

3. Discussion :
Soap is made by the saponification reaction. It is an exothermic chemical reaction which happens
when fatty acids react with base. This process involves boiling the fats together with the base. For
this experiment, we boiled coconut oil with 29.5g NaOH. The hydrolysis of the oil occurs, thus
producing glycerol and crude soap. Then, sodium chloride is added into it once the saponification
reaction completed. Addition of sodium chloride causes the soap to precipitate. The crude soap
acquired from the process consists of sodium chloride, sodium hydroxide and glycerol. The crude
soap curds is then boiled in water and re-precipitated with salt in order to remove the impurities.
Saponification Reactions: Fat + Lye → Soap + Glycerol

4. Conclusion :
In conclusion, the soap is successfully prepared and the comparison properties of soap, which are
precipitation are made, observed and recorded. It can be concluded soap is also a good cleaning
agent but decrease in effectiveness as it used in hard water. The presence of scum tends to remain
behind and deposits on the cloth. The quantity of the soap formed depends on the amount of
reagents used. This procedure is applicable even in industrial set ups. The sodium chloride is used
for the purposes of salting out and helps in the crystallization of the soap.
Questions and answers :
1) What are the additives usually used in the preparation of bath soap or detergent?
There are many different soap making ingredients that can be used to create soap at home.
Whether it's a base, fat, oil, nutrient, natural preservative essential oil or colorant each
substance has specific benefits for soap making.
2) What do you expect if olive oil is added into the soap formulation (coconut oil + olive oil)?
High amounts of coconut oil can be drying, however you can always use a higher superfat
to counteract the drying effect. The more un-saponified oils in your soap the more
moisturizing it is. Experiment with a 100% coconut oil soap with a 20% superfat.
Meanwhile, The low cleansing properties of olive oil make it very mild and nourishing.
Soap for sensitive skin, elder skin or baby skin should include high amounts of olive (60%).
Castile soap is made with 100% olive oil. Classify this as a soft/hard oil because it makes
a very soft bar of soap initially upon unmolding but cures into a rock hard bar. Soaps high
(50%+) in olive oil need longer to cure and unmold.
3) Saponification reaction can take place without external heating. Explain how the internal
heat can support this saponification process?
Although cold-process soapmaking takes place at room temperature; first, the fats are
heated to ensure the liquification of the fats used. Then, when the lye water solution is
added to the fats, it should be the same temperature of the melted oils and both are typically
between 80-90° F. An external heat source is not necessary but the molded soap should be
incubated by being wrapped in blankets or towels for 24 hours after being poured into the
mold. Milk soaps are the exception. They do not require insulation. Insulation may cause
the milk to sour. The soap will continue to exothermically give off heat for many hours
after being molded. During this time, it is normal for the soap to go through a "gel phase"
where the opaque soap will turn somewhat transparent for several hours before turning
opaque again. The soap may be removed from the mold after 24 hours but the
saponification process takes several weeks to be complete.

5. References :
1) “Fats, Oils, Fatty Acids, Triglycerides - Chemical Structure” a webpage by
ScientificPsychic.com accessed Nov 2, 2004 at
http://www.scientificpsychic.com/fitness/fattyacids.html
2) Paul Kelter, Jim Carr and Andrew Scott, Laboratory Manual to accompany Chemistry a
World of Choice, McGraw-Hill, Boston, 1999.
3)