Post-Lab 4: Saponification

Saponification

The process by which soaps, carboxylate salts with very long hydrocarbon chains, are made from the base hydrolysis of a fat or an oil

Animal fat and lye (NaOH)

Traditionally, soaps were made from _____

Esters

They are converted into carboxylate salts when treated with sodium hydroxide (NaOH)

Carboxylic acids

Neutralization of carboxylate salts yield _____

deprotonated

If a base (usually NaOH, sometimes KOH) is used for hydrolysis, the fatty acids produced are _____ and are present as its corresponding carboxylate salt

soluble

Charged carboxylate salts are _____ in water than the uncharged fatty acids

Nonpolar

Carboxylate salts have a long (polar/nonpolar) tail

Sodium palmitate

Common soap ingredient

Irreversible

Saponification under basic conditions is _____

Micelles

Soaps are able to emulsify fats and oils by forming _____ around oil droplets

Dispersion

Enough soap molecules surrounding the oil droplets facilitate the _____ of the oil droplets in water where they can be easily washed away

Using lots of soap

Method of breaking down fat/oil
→ To accommodate more fat molecules

Using hot water

Method of breaking down fat/oil
→ To melt solid fats

Agitation

Method of breaking down fat/oil
→ To break down fats and oils into smaller droplets

Glycerol and three fatty acids

Fats and oils are triesters of _____

Insoluble; hydrophobic

Fats, oils, and fatty acids are generally _____ in water because of the presence of long _____ tails

Vacuum filtration

Formation of negative pressure at the outlet of the filtrate and using it as the driving force of filtration → accelerates the filtration process

Use: to obtain a filter residue with low moisture content

Solid soap sample

End product of the experiment

White, solid clumps with little to no moisture

Expected result of soap solution after being subjected to vacuum filtration

50ml of 30% NaCl

Some soap samples hardened or formed solid clumps as soon as _____ solution was added, but some soap samples remained liquid even after the ice bath

• Too much coconut oil

• Portion of NaOH solution not dispensed properly

• Inadequate mixing

Possible sources of error in the soap samples

4 weeks

Curing time for soaps lasts for around _____ where the soap lose more water and become milder

7 to 10

Homemade or laboratory made soap should have a pH level that ranges from ph _____

greater than 10

Soaps that have a pH level _____ are considered lye-heavy and can irritate or burn the skin

24 hours

Saponification reaction takes around _____ and continues to become milder with time

Colloidal

When shaking the soap mixed with water, the soap solution becomes _____ in nature

foaming

Agitation (by mixing) concentrates the solution on the surface which causes _____

Height

Foaming capacity of the soap samples is usually based on the ____ of the foam created after agitation

Surfactant

Substances that reduce the surface tension in the liquid

Surface tension

Soap reduces the _____ of the water, making its molecules less likely to stick together and more likely to interact with oil or grease

Hydrophilic

The (hydrophobic/hydrophilic) part of soap molecules interact with the water molecules in solution, forming the outer surface of the micelle

Hydrophobic

The (hydrophobic/hydrophilic) part of the soap interacts with the oil, trapping the oil in the center

Hard water

Water that contains a significant concentration of Mg²⁺ and Ca²⁺ ions

Soap scum

Precipitates with soap molecules formed by Mg²⁺ and Ca²⁺ ions

Less emulsification capacity and less foam formed

Result of soap forming precipitates with Mg²⁺ and Ca²⁺ ions

Hard

Soaps are less effective in _____ water

Soft water

Water that contains very few or no ions that precipitate with soap

Soft

Soaps are more effective in ____ water

Detergents

• Similar to soap (also have a charged head group and long hydrophobic tail)

• However, they are not prepared from natural fats or oils

Detergents

Work effectively both in soft and hard water (they don’t form precipitates)

Sodium lauryl sulfate

Typical ingredient found in commercial shampoos and other cleaning products

Sodium lauryl sulfate

Nonbiodegradable detergent

Sodium laurylbenzenesulfonate

Biodegradable detergents were developed substituting sodium lauryl sulfate with biodegradable compounds like _____

Phosphate

Excessive amounts of _____ in bodies of water accelerate the growth of algae which consumes too much of the dissolved O₂ in water

Bile salts

Lipid emulsification in the body is primarily facilitated by _____

Amphipathic nature

The _____ of bile salts aid in the digestion of fat droplets in the body, preventing their reaggregation

Galbladder

Bile salts are stored in the _____, which is stimulated to contract and secrete the bile when food passes from the stomach into the duodenum

Steroidal

Bile salts are _____ detergents
→ Form mixed micelles with lipids, dats, and/or cholesterol, and thus enable the digestion and absorption of fats and fat-soluble vitamins in the intestine