Soaps - saponification

sources of fats and oils (lipids)

typically found from animals or plants

Animal fats= solid at room temp: saturated fats (all carbon-carbon bonds are single bonds)

plant oil: liquid at room temp = unsaturated fats (contain one or more double or triple C-C bond.

fats and oils

contain large non-polar (have no overall dipole in the molecule) molecules (triglycerides)

• fats and oils are distinguished through their physical state at room temp.

being non-polar they are unable to form bonds with water - non-soluble

tryglycerides

synthesised by a condensation reaction between a glycerol molecule and 3 fatty acids

fatty acid

• carboxylic acids with chain lengths of eight or more carbon atoms

• have a carboxyl functional group attached to the hydrocarbon tail

glycerol

• a small molecule with 3 hydroxyl functional groups

condensation reaction to form triglycerides;

saponification

to form a soap the ester links in the triglyceride must be broken in a hydrolysis reaction (using a strong base such as NaOH)

by product is gycerol

all soaps are made up of a:

• long hydrocarbon chain

• carboxylate ion (COO-)attached to the hydrocarbon tail, is polar

• a metal ion normally Na+ or K+

limitation of soaps

• soap with form

detergents

contain a hydrocarbon chain sourced from petroleum products, do not form insoluble salts with calcium or magnesium ions

anionic detergent

a type of detergent where the hydrophilic (water-attracting) part of the molecule carries a negative charge

cleaning action of soaps

1. non-polar tail dissolves into grease through dispersion forces, which are stronger than the dispersion forces in grease

2. ion-dipole and H-bonds are formed from the carboxylate group on the soap and water

3. interactions are stronger than the H-bonds in water therefore dissolving into water

4. through agitation grease and oil molecules are able to be removed in the form of micelles

how does soap work in water

how does soap clean oil off of a surface

structure of a detergent

why does soap not work in hard water?

what is hard water

water with a relatively high concentration of cations (Mg and Ca

why are soaps basic?

soaps are salts of long chain fatty acids formed from a strong base and a weak acid, therefore they are basic.