C14 - alcohols Flashcards
methanol uses
- good fuel
- efficient combustion
- paints
- antiseptics
- adhesives
volatility meaning
physical state change liquid to gas
more volatile = less energy needed to turn into gas
alcohol Vs alkene volatility
alcohol = strong IMF = more energy needed = less volatile
alkene = weak IMF = less energy = more volatile
solubility in alcohols
alcohol = polar so can H-bond with water
- solubility decreases for larger alcohols as more LF compared to OH, so is harder for polar solvent to overcome
Why do alcohols have a higher melting point than alkanes?
polar so stronger London forces & H-bonds
oxidation colour change
orange –> green
oxidation agent for oxidising alcohols
acidified potassium dichromate
K2Cr2O7/H+
primary alcohol –> aldehyde
- 1 mole of K2Cr2O7 & H2SO4
- distil
primary alcohol –> carboxylic acid
- 2 moles of K2Cr2O7 & H2SO4
- reflux
secondary alcohol -> ketone
- 1 mole K2Cr2O7 & H2SO4
- reflux
Why are carboxylic acids refluxed?
To ensure any aldehydes formed initially are oxidised into carboxylic acids
Why can’t tertiary alcohols be oxidised?
Very stable carbocation, so no reaction
- no colour change as stays orange
Alcohol + _____ —-> haloalkane + H2O
NaX or HX, H2SO4 catalyst & reflux
- nucleophilic substitution
How is HBr made?
NaBr(s) + H2SO4 –> NaHSO4 + HBr(aq)
formed in situ, as is very toxic
alcohol –> alkene
- dehydration
- elimination rxn
H3PO4 catalyst & reflux
