Soap

Soap formulation

Date of experiment : 28 April 2015

Introduction

Saponification is a process that produces soap, usually from fats and lye.The term saponification is the name given to the 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 enter into the chemical reaction. The water is only a vehicle for the alkali, which is otherwise a dry powder.

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.

Objectives 

At the end of the practical the students should be able to:

1.Understand the rationate behind the use of the different types of ingredients in  a shampoo formulation.

2.Understand the acid-base reaction (saponification process)by which soap is produced.

3.Evaluate the quality of the products that have been produced.

List of chemicals/items

Oliver oil,vegetable shortening,coconut oil,potassium hydroxide,sodium hydroxide,glucerin,alcohol,castor oil,distilled water,fragrance and essential oils,colourants, honey,oatmeal,tea,coffee,cocoa,vitamin E and camphor

Honey and oatmeal soap bar

Coconut oil	19.6%
Olive oil	19.6%
Vegetable shortening	29.6%
Sodium hydroxide	9.9%
Dsitilled water	20.9%
Honey	0.17%
Oats	0.23%
Colourants	0.23%
Fragrance/essential oils	0.23%

Procedure

1.Prepare the mold

-Molds were cleaned and dry completely.They also were greased with petroleum jelly.

2.Weighing out the fats

-By using a weighing scale,the fats and oils were weighed out.

3.Melting the fats

-All the fats and oils were mixed in a beaker and  the mixture were  heated to around 40-50⁰C.Then the mixture was removed from the heat.

4.Preparing sodium hydroxide solution

-Sodium hydroxide and water was weighed out.Sodium hydroxide was added to water and mixed well.The solution was cooled down.

5.Mixing

-When the sodium hydroxide was completely dissolved in water,the solution was poured into the warm oil mixture in the beaker (the oil become opaque).

-The solution was mixed for 15 minutes  in circular motion  constantly.After a short rest,they was mixed more until thickened.

6.Adding fragrance/Essential oils/other ingredients.

-The mixing was stopped when the mixture form “trace”.(A line or circle on the mixture was drawed to confirm tracing has occurred.The mixture was traced when the line/circle stays on the surface.

-Honey,oats and fragrance was added and was mixed well.

7.Pouring in the mold

-The soap was poured into the mold.Themold was covered and keeped moderately at a warm place.Themold was covered with cloth and leaved for 24-48 hours.

8.Curing

-The soap was removed from the mold.

-As plastic mold was used,themold was freezed for 1-2 hours before  taking the saop out to avoid the soap from sticking to the mold.

-The mold was rested in a cool place for the next 3-4 weeks.

-Any ‘ashy’ powder formed on the soap surface was scraped.

Result

I.Retention of bubble

Weight of soap	Bubbles start to appear	Bubbles start to dissapear	Bubbles totally dissapear
1.5 g	After 1st minute	After 2nd minute	After 4th minute
2.5 g	After 1st minute	After 4th minute	After 6th minute
3.5 g	After 1st minute	After 6th minute	After 8th minute

II.Boiling point

Some pieces of soap were heated on water bath according to the temperatures:

60 ⁰C	No reaction on soap
80 ⁰C	No reaction on soap
100 ⁰C	No reaction on soap

III.Irritation

Everyone of each has to wash our hands using the soap :

A	No irritation
B(sensitive skin)	No irritation
C	No irritation
D(sensitive skin)	No irritation
E	No irritation

IV.ph

We tested a red litmus paper in soap  three times:

	Colour change	Ph scale
1st trial	Red litmus turns to blue	8
2nd trial	Red litmus turns to blue	8
3rd trial	Red litmus turns to blue	9

 Discussion

Soaps are made in a chemical process called saponification. In this reaction, the triglycerides are hydrolyzed into free fatty acids and glycerol. Fatty acids have very useful property of having one end that is hydrophilic, which is also the “acid” part and another end that is hydrophobic which the “fatt” part is. This dual nature allows soaps to dissolve in fat, grease and dirt in water and bring out a very good cleansing property.

General overall saponification  reaction:

Fat + NaOH   →   glycerol + sodium salt of fatty acid

  We had do some test to our soap which is retention of bubble,boiling point,skin irritation and pH.Based on the result,our soap produce bubble and it does not disappear for a long time depending on the weight of soap used.The long time bubble retention proves that our soap works effectively.For boiling test,when we boil various weight of soap,it turn out that no change happen.As there are no change in shape and structure of the soap,it is proven that the soap is stable in structure.Furthermore,we had conducted a skin irritation test for both normal skin and sensitive skin.For both type of skin,there is no skin irritation detected which shows that our skin is good to use buy people of various type of skin.Last but not least,we had performed the pH test on our soap.The result shows the litmus paper turns to blue and the pH indicator shows the pH at 8 which prove that it is in alkaline state.Soap should be in alkaline state and we had managed to produce the soap that is alkaline.

 Conclusion

In conclusion,from this experiment,we get to understand the rational behind the use of the different types of ingredients in  a shampoo formulation.We already understand the acid-base reaction (saponification process)by which soap is produced as well and lastly,we get to evaluate the quality of the products that have been produced.

References 

1. http://www.millersoap.com/phtome.html
2. http://science.uvu.edu/ochem/index.php/alphabetical/s-t/saponification/
3. http://www.gutenberg.org/files/21724/21724-h/21724-h.htm