Burhan Riaz

03/18/2011

CHM 2211L-0017

Soaps and Detergents

Introduction: In this experiment soap is produced from a two step process which includes a

nucleophyllic acyl substitution reaction and a neutralization reaction. The entire process is called

saponification which is the reaction of a fat or oil with aqueous hydroxide ion to yield carboxylic acid

salts of fatty acids. Techniques that are used include vacuum filtration, salting out the product, and

refluxing.

Safety Concerns:

Sodium hydroxide

Ethyl alcohol

Main reaction and Mechanism:

Two side products were formed; diglyceride and monoglyceride

Results and Discussion:

Reaction Equation:

Calculations:

Analytical Purity:

Side products formed:

Experimental:

In a beaker, add 20mL H2O, 20 mL 95% EtOH, 5g NaOH. Mix until the solution is dissolved. This

creates a NaOH solution and now must be salted. In a 400mL beaker, add 150mL of H2O and 50g NaCl.

Nix until it is dissolved and then cool it to room temperature using an ice bath. Take 10g of lard and

40mL NaOH and place into a 250mL round bottom flask with a refluxe condesor attached. Heat for 45 to

60 minutes with stirring. Pour the mixture into a 400mL beaker that has 150mL NaCl solution. Mix for 5

minutes and cool to room reaction. Use a vacuum filter to gain the final product.

A test on the soap is performed by preparing a solution of .15g soap dissolved in 10mL H2O.

Shake 15 seconds and let it stand for 30 seconds. Add 4 drops of CaCl2, shake for 15 seconds, and let it

stand for 30 seconds. Add 1 g of Na3PO4, shake for 15 seconds and let it stand for 30 seconds. Record

results.

Source: Xanedu Coursepack CHM 2211 UCF Spring 2011

Questions 1,2,3,4,5

1. Why should the K salts of fatty acids yield soft soaps? because they are more soluble in water than

sodium salts of fatty acids (which yield hard soaps). They contain more water, so they are softer.

2. Why is the soap derived from coconut oil so soluble? The primary fatty acid of coconut oil is laureate,

a 12 carbon chain. After Saponification there is a relatively high ratio of glycerin to oil and the fatty acid

salts are more soluble than would be with longer chain fats.**

3. Why does adding a salt solution cause soap to precipitate?

It can form an insoluble compound that will precipitate with a soap molecule that is known as soap

scum.**

4. Why do you use a mixture of ethanol and water rather than simply water in the saponification

reaction? Because the ethanol allows the oil to mix with the solution better. Water and

oil do not mix, however, if you add ethanol to the mixture it will mix with the

oil to form a solution.

5. Sodium acetate and sodium propionate are poor soaps. Why? Because they do not have a long

enough hydrocarbon side to bind to dirt. Therefore there is not enough non polar substance in the

molecule to bind to nonpolar dirts, fats and oils. **

Literature Article "Soaps and Detergents"

Chemistry 49 (Sept. 1976) : 6

1. What was the title of this article?

Detergents, soaps and syndets

2. Who was the author?

Clifton E. Meloan

3. What chemical company first discovered floating soap by accident?

Proctor and Gamble

4. What caused the soap to float?

Extra boiling whipped air into the soap; rapid cooling trapped the air there.

5. In order to function, as a detergent, what property must a substance have?

Must reduce surface tension 72 to 30 dynes per cm^2

6. Approximately what % of soap is needed to form an effective detergent?

8-18%

7. Name one cationic detergent mentioned in this article:

Octadecyl ammonium chloride

8. Why are emulsifiers added to detergents?

To prevent dirt particles from redepositting on a fiber.

9. Why is sodium silicate added to detergents?

Helps prevent corrosion.

10. Why are enzymes added to detergents?

To hasten breakdown of protein and large molecules.