Industrial Lab 4

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OBJECTIVE

After completing this experiment, the student should be able to:

1. Prepare a soap starting with olive oil

2. Examine the chemical properties of the soap that is made.

3. Understand what saponification means.

4. Understand how soap cleans.

INTRODUCTION

The name saponification literally means "soap making". The root word, "sapo", is Latin for soap.

The Italian word for soap is sapone. Soap making as an art has its origins in ancient Babylon

around 2500 - 2800 BC.

The oils used in modern handmade soap are carefully chosen by the soap maker for the character

they impart to the final soap. Coconut oil creates lots of glycerin, makes big bubbly lather, and is

very stable. Olive oil has natural antioxidants and its soap makes a creamier lather. Tallow, or

rendered beef fat, makes a white, stately bar that is firm and creates abundant lather. Many other

oils can be used, each one for a specific reason. Your soap maker will be glad to tell you which

oils are used to make her or his soap.

The alkali used in modern soap is either potassium hydroxide, which is used to make soft soap or

liquid soap because of its greater solubility, or sodium hydroxide, which is used to make bar

soap. The common term for the alkali became simply "lye", which curiously is not short for

alkali, but originated in the Anglo-Saxon language.

Soap made in cottages and on farms in earlier American times became known as "lye soap". That

term is now pejorative and derogatory and denotes a harsh soap that would irritate your skin. The

old soap got a bad name because it had an excessive amount of caustic. Weighing and measuring

techniques were crude, and knowledge of soap chemistry was elementary or non-existent.


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The true fact is that modern handcrafted soap, though necessarily made with lye to get true soap,

has no lye in the final product. It has all been reacted with the oils to form soap and glycerin.

A curious fact about modern soap is that most common soap found in the grocery store made in

mass-produced factories does have a small amount of excess alkali in it. Also, it has had all of its

naturally-occurring glycerin removed so it can be sold as a separate commodity. Why? Greater

profit. An important difference between most commercial soap and our Real Handmade soap is

that the glycerin is left in Real Handmade Soap and thus it retains its natural moisturizing

property.

MATERIALS AND APPARATUS

20 ml olive oil

30 ml of 95% ethanol

Beaker and glass-stirring rod

Hotplate

NaOH solution

3g of NaCl

100 ml of deionized water and ice

Buchner funnel and filter paper

SAFETY CONSIDERATION

1. All the instructions and modification of the experiment performed by student must be

authorized and supervised by the lab tutor.

2. Safety equipment such as goggles (eye), gloves (skin) and lab coat was used during the

experiment when dealing with highly concentration and/or toxic substance in order to

avoid any contact with skin or eyes.

3. All the equipment which was used must be washed cleanly by using distilled water before

and after using it in the experiment.


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PROCEDURE

1. About 20 ml olive oil was added to a 200 ml beaker and it was dissolved in a 30 ml of

95% ethanol.

2. When the olive oil was completely dissolve, put the beaker on the hot plat and the

temperature was maintained to about 85C. The flask was swirled to mix the solution.

Next, 20 ml of 50% NaOH solution was poured down the glass-stirring rod into the oil

solution. A small amount of the NaOH solution was trickled down the rod very slowly

and the stirring was stopped. Then, a little more NaOH solution was trickled in. The

mixture was stirred until it thickens.

3. A small watch glass was placed over the mouth of the flask to minimize evaporation of

the alcohol.4. The oil-alcoholic-NaOH solution was allowed to boil for at least 30 min. If an un-

dissolved fat was observed in the flask, a little more ethanol was added to the flask and

stir to dissolve the fat. The temperature was kept just hot enough to had controlled boiling

of the fat solution.

5. While the saponification proceeds, a salt solution was prepared by completely dissolving

30 g NaCl in 100 ml deionized water in a 250 ml beaker. After the salt completely

dissolves, about half of this salt solution was transferred to another beaker and both

beakers were placed on ice to cool down.

6. After 30 min, the fat solution was tested to see if saponification is complete by placing a

few drops of the solution in a test tube of deionized water. If fat droplets float to the top,

the saponification is not completed and it was allowed to boil for an additional 10 min.

7. When the saponification was completed, the hot reaction mixture was carefully poured

into one beaker of salt solution and stirred for a minute or two. The mixture was allowed

to cool for 24 hours before filtering.

8. A suction filtration with a Buchner funnel and filter paper was set up. The mixture from

step 7 was filtered and the soap was washed twice with cold salt water. Air was drawn

through the soap for a few minutes to remove most of the water.

9. The soap cake was removed from the Buchner funnel and it was saved for the following

tests.


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RESULT AND DISCUSSION

Results taken during conducting experiment:

Olive oil used

Mass is 17.2015g and the volume is 20 ml

NaCl used

Mass is 30.0355g

Calculation

1. Type of oil used: Olive Oil

2. Weight of oil taken: 17.2015g

3. Weight of NaOH used: 30.0355g

4. Weight of soap formed: 109.4g

5. Theoretical yield

Theoretical yield ( )

()


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6. Percentage of yield

According to the objective, I have understood the meaning of saponification and how soap clean.

Saponification is a chemical reaction that occurs when a vegetable oil or animal fat is mixed with

a strong alkali. The products of the reaction are two: soap and glycerin. Water is also present, but

it does not involve in the chemical reaction. The water is only a tool for the alkali to dilute,

which is otherwise a dry powder. Soap is able to be an excellent cleaner 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 (dirt) in such a way that it can be removed.

CONCLUSION

All the objectives have been achieved. I have understood the meaning of saponification and how

soap has the cleaning ability.

LIMITATION

Do not pour the NaOH solution into the oil too quickly. Pouring the NaOH solution too

quickly will cause the oil to separate from the NaOH solution, and your final product will

be a failure.

Do not use high heat to boil or the alcohol will evaporate.


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REFERENCES

http://chemistry.about.com/od/cleanerchemistry/a/how-soap-cleans.htm

http://www.realhandmadesoap.com/folders/FAQ/what_is_saponification.htm

K. Schumann, K. Siekmann Soaps in Ullmanns Encyclopedia of Industrial Chemistry

2005, Wiley-VCH, Weinheim. doi:10.1002/14356007.a24_247

Thorsten Bartels et al. "Lubricants and Lubrication" in Ullmann's Encyclopedia of

Industrial Chemistry, 2005, Weinheim. doi:10.1002/14356007.a15 423


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Industrial Lab 4

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