Experiment 02 May 21, 2015 7 of 7
CHM144L/ A41 Industrial Chemistry Laboratory
4th Quarter SY 2014-2015
Mapua Institute of Technology
School Of Chemical Engineering and Chemistry
Chemical Process Industries Laboratory
Experiment 2
Soap Making
Joseph Bien M. Odiña
Student
Mr. Medarlo De Jesus
Professor
OBJECTIVES
To be able to prepare various type of soap.
To understand the process of making soap.
To identify the various roles of the raw materials in making soap.
INTRODUCTION
Soap is a salt of a fatty acid. Soaps are used as surfactants for washing, bathing, and cleaning, but they are also used in textile spinning and are important components of lubricants. Soaps for cleansing are obtained by treating vegetable or animal oils and fats with a strongly alkaline solution. Fats and oils are composed of triglycerides; three molecules of fatty acids are attached to a single molecule of glycerol. 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 liberated glycerol (glycerin). The glycerin is a useful by-product, which can be left in the soap product as a softening agent, or isolated for other uses.
Soaps are key components of most lubricating greases, which are usually emulsions of calcium soap or lithium soaps and mineral oil. These calcium- and lithium-based greases are widely used. Other metallic soaps are also useful, including those of aluminum, sodium, and mixtures of them. Such soaps are also used as thickeners to increase the viscosity of oils. In ancient times, lubricating greases were made by the addition of lime to olive oil.
In this experiment, three kinds of soap will be made. The first is an opaque soap made through the cold process. The other is an opaque soap but done through the hot process. The last one is the transparent soap. The process of making soap will be understood at the end of the experiment. Also, the effects and uses of the different reagents will be determined.
MATERIALS AND METHODS
The materials used in this experiment were hot plate with stirrer, electronic balance, spatula, 250 mL beakers, 50 mL beakers, 100 mL graduated cylinder and pH meter. The chemicals used were coconut oil, sodium hydroxide pellets, stearic acid, glycerin, white sugar, ethanol, propylene glycol, lauric acid, myristic acid, food coloring and essential oil.
This experiment was divided into three. In making the opaque soap, there were two processes. One was the cold process and another was hot process. Also, the process of making the transparent soap was also performed.
In doing the opaque soap through the cold process, the amount of materials needed were calculated and weighed. The 37% NaOH was made by dissolving 18. 25 g of NaOH pellets in 31 mL of water. 100 g of coconut oil was placed in a 250 mL beaker. Then, the NaOH solution was poured slowly in the coconut oil while constantly stirring the mixture. It was stirred until a viscous mixture was obtained. This was poured in the molder and allowed to harden for a few minutes. It was removed from its container and weighed. After that, a 1% soap solution was prepared to get the pH. Then, the % difference and % recovery were computed.
For the hot process, same with the cold process, 256 was the saponification value used for the coconut oil. The chemicals were weighed. Again, 18.25 g of NaOH pellets was dissolved in 31 mL of water. The coconut oil was heated for about 70°C. The NaOH solution was poured to the coconut oil slowly with constant stirring through magnetic stirrer. It was stirred until a viscous mixture was obtained. Then, it was poured into the molders and allowed to harden. It was removed from the molders and the weight of the soap was determined through the electronic balance. After that, a 1% soap solution of sample was prepared to determine its pH. The % difference and the % recovery were computed for the opaque soap made using hot process.
In making the transparent soap, the required materials were weighed. The 50% of the required water was placed in a beaker to dissolve the NaOH pellets. The remaining 50% of the water was placed in a separate beaker to dissolve the sugar until it totally dissolved. Then, the glycerin, propylene glycol, stearic acid, lauric acid and myristic acid were added in the stainless steel vessel. The mixture was heated to 70°C and was gently stirred. The NaOH solution was poured to the vessel slowly with constant stirring. It was heated with careful stirring until the mixture was homogenous. Then, the sugar solution, essential oil and food coloring were added. The hot mixture was poured into the molders. It was allowed to harden and removed from the molder. It was weighed. The % recovery, % difference were computed and the pH for the transparent soap was determined.
DATA AND OBSERVATIONS
Table 1. Results After Doing the Cold, Hot Process and Transparent
Process
Observations
Weight
% Difference
% recovery
pH
a. Opaque: Cold
After mixing the NaOH sol'n to the coconut oil, the mixture turned into creamy color and became thick.
Not too bubbly when used
135.09 g
10.48%
90.51%
11
b. Opaque: Hot
It was easier to produce a thick mixture.
Creamy color
Produced solid particles due to heating
129.69 g
15.08%
86.9%
11
c. Transparent
Yellow color
More ingredients were necessary in doing this but it required less time and effort in order to come up with the final product.
Bubbly compared to the two soaps
137.6 g
9.01%
91.73%
9
DISCUSSION
After doing the opaque soap through the cold and hot process, it was seen that it took more time and effort for the cold process to have a viscous mixture than the hot process. It is due to heating the mixture. Since the cold process didn't involve any heating, it took a lot of hours before obtaining a viscous mixture unlike the hot process, wherein it took only minutes for the mixture to be viscous. Also, the two processes gave almost the same product which was creamy in color. Another thing, the two soaps were bubbly when used. In Table 1, it can be observed that the % difference of the cold process is less than the % difference of the hot process and the % recovery of the cold process is greater than the % recovery of the hot process. This was because more losses were obtained in the hot process when transferring the mixture to the molder or when removing the soap from the molder. Since making opaque and transparent soap was easy and the % recovery of the soaps was high, it shows that the production of soaps is very efficient.
In performing the cold and hot process, the NaOH solution was added in the coconut oil. Coconut oil is often used in making soaps because of its good lather, lively bubbles and very great in adding hardness to the soap. It also nourishes the skin, keeping it soft and smooth. Coconut oil is light and greasy, leaving the skin with a radiant and glowing sheen. Also, it has a defatting effect on skin and has good cleansing properties. The 76 degree coconut oil was used in the experiment. In the hot process, it oil was heated to 70°C so there is a possibility of decreasing the amount of oil. Lye is a highly concentrated or aqueous solution of sodium hydroxide which is really used in making soaps. The hydroxide ion combines with the oil to form the soap. Since the oil is an acid and the NaOH is considered to be a strong base, there will be neutralization reaction.
The pH of the solution for the hot process and cold process were the same which was 11. From that, it can be inferred that NaOH which is a strong base was the one responsible for making the solution basic. It overpowered the acidity of the coconut oil.
More reagents/ chemicals were used in making the transparent soap unlike from doing the opaque soaps. And making the transparent soap was a lot easier than making the opaque soaps although there were a lot of materials used in this part. Also, from the three soaps made, the transparent soap had the highest % recovery and a pH of 10 which may be due to the amount of NaOH added to the solution.
The reagents used in making the transparent soap have their own uses that help in making good quality soap. After adding ethanol, the solution was still clear. This is because ethanol helps in making a see- through, glass- like or transparent soap. The higher the proof of the alcohol, the more transparent the soap is. Proof is the unit of measurement used to identify the potency of alcohol. Also, ethanol helps in hardening the soap. When the sugar solution was added, bubbles suddenly appeared. This is because sugar is responsible for the formation of bubbles or increasing the lather. The glycerin and propylene glycol were added in the solution to help in moisturizing the skin. The remaining reagents like lauric acid, stearic acid and myristic acid were accounted for hardening the transparent soap. Aside from hardening the soap, the lauric and myristic acid is best in promoting fluffy lather and cleaning very well. In line with this, large amount of the lauric acid and myristic acid may result to excessive drying because of its amazing cleansing properties. Also, the stearic acid can give a creamy or stable lather for the soap solution. All these reagents/ chemicals used for this experiment have their own uses or effect in the product.
CONCLUSION AND RECOMMENDATIONS
All the objectives of this experiment were achieved. First, three kinds of soaps were made. These are the opaque soaps done through cold and hot process and the transparent soap. Second, the process of making the soap was understood. For the cold process, the 37% NaOH solution was added to the coconut oil. Constant stirring was done until a viscous mixture was obtained. This was poured into the molder and allowed to harden. Same procedures were done for the hot process. The only difference was that the coconut oil was heated to about 70°C. It was seen that it took so long for the solution in the cold process to be viscous unlike in the hot process wherein the solution became viscous after a few minutes. For the transparent soap, the glycerin, propylene glycol, stearic acid, lauric acid and myristic acid were mixed and heated until 70°C. The ethanol was added, then the NaOH solution and sugar solution were also put in the mixture. This was stirred constantly and poured in the molder. The last objective was also met since the different effects or uses of the reagents/ chemicals used in the experiment were determined. For the hot and cold process, the coconut oil was used since it's known for its , good lather, cleansing, moisturizing properties and great in hardening the soap. The NaOH when added to the oil formed soap and also, it made the product basic. In the transparent process, the ethanol was added to make the soap see- through or glass- like look. It also helped in hardening the soap. Another reagent added was sugar to help in the formation or bubbles because of its superb lather. In terms of the moisturizing properties, the glycerol and propylene glycol were accounted for. The lauric acid and myristic acid helped in hardening the soap and promoting its fluffy lather and cleansing properties. Lastly, the myristic acid was responsible for the creamy or stable lather of the solution.
The % recovery for the three soaps was high which infers that the production of soaps is very efficient. It wouldn't be that hard to make soap as long as you have the materials or chemicals to be used for the experiment. And the % recovery will be improved by being careful in transferring the solution in one container to another to avoid too much loss of it.
REFERENCES
Fatty Acids and Soap Making. Soap Making Supplies. Retrieved May 12, 2014 from http://www.soap-making-resource.com/fatty-acids-soap-making.html.
Why is Ethanol Used to Make Soap?. (2014) Demand Media Inc. Retrieved May 5, 2014 from http://www.ehow.com/about_6384669_ethanol-used-make-soap_.html.
Soap. (2014). Wikipedia. Retrieved May 12, 014 from http://en.wikipedia.org/wiki/Soap.
SAMPLE COMPUTATIONS
For Cold Process:
Theoretical weight=100 g+18.25 g+31 g
Theorerical weight=149.25 g
% Difference=theorerical weight-actual weighttheorerical weight x 100
% Difference=149.25-135.09135.09 x 100
% Difference=10.48%
% Recovery=actual weighttheorerical weight x 100
% Recovery=135.09 149.25 x 100
% Recovery=90.51%
