Alcohols Flashcards
Alcohols general formula
CnH(2n+1) + 1OH
How do we know if something is a primary (1°), secondary (2°) or tertiary (3°) alcohol?
See how many carbon atoms that the C with the OH functional group is attached to
Do alcohols have a high or low melting point?
High
Explain the melting point of alcohols
Alcohols have hydrogen bonding between the molecules, so they have higher melting points than alkanes
Do branched alcohols have higher or lower melting points?
Lower
Explain the difference in boiling points of branched vs unbranched alcohols
Branched molecules don’t fit together as closely so less energy is required to pull them apart.
Are alcohols soluble in water?
Yes
Explain the solubility of alcohols in water.
Alcohols are soluble because they form hydrogen bonds with water.
What happens to solubility as the alcohol gets longer? Explain.
The longer an alcohol gets, the less soluble it becomes. The non-polar end of the molecule (everything except the -OH group) cannot interact with the water (it’s hydrophobic) so therefore is not soluble in water. When the molecule is longer, the hydrophobic part of the molecule becomes more significant than the hydrophilic (polar) part, so the molecule becomes insoluble.
What is the first insoluble alcohol?
Octanol
Why do longer alcohols have a higher boiling point?
Greater London forces
What are the 3 methods of preparing alcohols?
Fermentation, hydration of alkenes, hydrolysis of halogenoalkanes
What conditions are required for fermentation?
Anaerobic, 30-40°C, zymase enzyme, sugar, aqueous
What is the yield of fermentation?
Max 15% ABV (alcohol by volume)
What conditions are required for the hydration of alkenes?
300-400°C, steam, phosphoric acid catalyst, 60-70 atm
