A2- Fats and Oils Flashcards
What is are cis fats?
where the H are on the same sides of the double bond
What are trans fats?
where the H atoms are on different sides of the double bond
Describe the VDWs forces between cis and trans fats?
cis; are weaker as bulkier molecules, so cannot pack as close together
trans; longer and flatter, so stronger VDWs
What is the difference between fats and oils?
fats = saturated hydrocarbons so stronger VDWs so are often
solid
oils = unsaturated hydrocarbons so weaker VDWs therefore are liquid
Describe fats/oils in water
tend to be insoluble
What can the glycerol combine with?
OH groups from carboxylic acids
Finish the equation:
oils + methanol
(NaOH/KOH catalyst) -> methyl esters and glycerol
What is biodiesel?
a mixture of methyl ester fatty acids used as an alternative to traditional fuels
What process produces biodiesel?
transesterification
Why is transesterification used to produce biodiesel?
low temperature and pressure, 98% yield
Finish the equation:
fat/oil + 3NaOH
-> glycerol and sodium salt
What can be used to catalyse transesterification?
- An acid works by protonating the carbonyl group
- An alkali works by deprotonating the alcohol / methanol
- However, it is more common to use an alkaline catalyst such as NaOH / KOH
