Chm144L Experiment 2 Soap Making

Mapa Institute of Technology

School of Chemical Engineering, Chemistry, Biological Engineering and

Materials Science Engineering

INDUSTRIAL CHEMISTRY LABORATORY

Experiment 2

Soap Making

De Guzman, Anne K.

CHM144L/B31

Prof. Medarlo De Jesus

Instructor

Soaps are cleaning agents that are usually made by reacting alkali with naturally

occurring fat or fatty acids. Soap comprises the sodium or potassium salts of various

fatty acids, but chiefly oleic, stearic, palmitic, lauric, and myristic acids. For

generations, its use has increased until its manufacture has become an industry

essential to the comfort and health of civilized human beings. Tallow is the principal

fatty material in soap making. It is usually mixed with coconut oil in the soap kettle

or hydrolyzer in order to increase the solubility of the soap. Coconut oil has long been

important. The soaps made from the Coconut oil are firm and lathers well. It contains

large proportions of the very desirable glycerides of lauric and myristic acids. The

alkaline solution, which is often called lye, brings about a chemical reaction known

as saponification. In this reaction, the triglyceride fats are first hydrolyzed into free

fatty acids, and then these combine with the alkali to form crude soap, an amalgam

of various soap salts, excess fat or alkali, water, and glycerin. Soap is an excellent

cleanser because of its ability to act as an emulsifying agent. An emulsifier is capable

of dispersing one liquid into another immiscible liquid. This means that while oil

(which attracts dirt) doesn't naturally mix with water, soap can suspend oil or dirt in

such a way that it can be removed. The glycerin is a useful by-product, which can be

left in the soap product as a softening agent, or isolated for other uses.

DATA AND RESULTS

Opaque Soap

Cold Process

Mass NaOH 18.286 g

Volume of water 31.135 mL

Mass of Coconut oil 100 g

pH of 1% soap solution 11

% difference 13.48%

% recovery 86.52 %

Theoretical weight of the soap 149.421 g

Actual weight of the soap 129.28 g

Hot Process

Mass NaOH 18.286 g




% difference 11.78%

% recovery 88.82 %



Transparent Soap

Mass NaOH 18.286 g




% difference 10.79%

% recovery 89.21 %



DISCUSSION OF RESULTS

In the cold process, upon mixing the NaOH with the coconut oil, the color changed

from pale yellow to creamy yellow, and with thorough stirring the color

permanently changed to cream. While in the hot process, upon addition of the 37%

NaOH solution, coagulation was observed and upon cooling the soap whitened in

color. For comparison, the soap mixture made by hot process took a longer stirring

time to reach its viscous state than the cold process. The high percentage recovery

shows the efficient production of soap. The remaining error in bath processes may

have arised from the soap solution left in the initial medium where it was mixed

before pouring into the molder. Coconut oil, the base oil for opaque soap, has a

76 melting point and is great for adding firmness to the soap and has a superb

lather. Since the temperature for the hot process was only maintained at 70, it is

unlikely to vaporize that can result to a decrease in the amount of oil in the

solution. NaOH, commonly termed as lye, is an essential component in the soap

making reaction because its hydroxide ion combines with the oil or fat to form the

soap. Water is used just to dilute the initially solid NaOH pellets into a 37%

solution. The reaction between the oil and the NaOH is a neutralization reaction

since the oil is an acid while NaOH is known to be a strong base. The quality of the

resulting mixture or soap will be affected by the quantity of the oil and the base

added. The pH of the solution for both the hot and cold process is 11. Assuring that

the reaction must be a neutralization reaction and must form a more neutral

compound, the quantity of the NaOH used overpowered the acidity of the oil, hence

favoring the resulting basicity of the soap.

In making the transparent soap, a number of chemicals: glycerin, propylene glycol,

stearic acid, lauric acid and myristic acid were shown to not have dissolve

completely even with continuous stirring at room temperature. However at the

presence of heat, the seemingly solid substances dissolved in the colorless liquid.

With the addition of colorless ethanol, no noticeable changes occurred. A small

amount of bubbles appeared in the addition of sugar in the solution and was also

included when the solution was poured into molder. The pH of the soap was 10 and

may be caused by the smaller amount of NaOH added and the heating conditions

made while the solution was in presence of heat while NaOH was poured into the

mixture.

The opaque soap prepared in hot process is bubblier when used compared to the

soap prepared in cold process, while the transparent soap forms the most bubbles

when used.

CONCLUSION AND RECOMMENDATION

In this experiment, opaque and transparent soaps were successfully prepared with

opaque soap prepared in two different processes: hot and cold.

It was learned that saponification is the reaction that comes from the main reaction

to make soap. The two most commonly used simple methods to make soap are

called the cold process and the hot process. Both require a heat source and careful

calculations to ensure that no caustic base is left unreacted in the soap. The hot

process uses heat to speed the reaction resulting in fully saponified soap by the

time the soap is poured into molds. The cold process uses just enough heat to

ensure that all the fat is melted prior to reacting it with the base. The cold process

is simpler, requires less time and energy, while resulting in a creamier bar.

High percentage recovery can be obtained by performing caution in mixing the

solutions and particularly in transferring the soap mixture into the molders as

residues reduces the percentage recovery.

Chm144L Experiment 2 Soap Making

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