intro to alcohols

give 2 physical properties of alcohols:

• water soluble

• higher bpt than alkanes of similar mass due to H bonding between molecules

give the 2 methods for alcohol formation:

• hydration of alkenes (or electrophilic addition of alkenes w/ H₂SO₄)

• fermentation - ethanol

give the conditions required for the hydration of alkenes:

• H₃PO₄ catalyst

• 60 atm

• 600 K

• often XS ethene - high yield

draw out the mechanism for the hydration of ethene:

give the symbol equation and conditions for fermentation:

• C₆H₁₂O₆ → 2 CH₃CH₂OH + 2 CO₂ - separated by distillation afterwards

• anaerobic - to prevent oxidation of ethanol

• ~ 35^oC, yeast - enzymes

what is a biofuel? give one example:

• fuels derived from biomass that has recently died

• e.g. (bio)ethanol

why are biofuels often described as carbon neutral? why not?

• no net emissions of CO₂ to the atmosphere

• but fossil fuels are needed to make fertilisers/harvest crops etc. so not completely carbon neutral

evaluate the use of biofuels:

strengths:

• renewable

• carbon-neutral (mostly)

limitations:

• land used to grow biofuels is unable to be used for growing food

• biofuels in transport - petrol car engines would have to be modified to use fuels w/ high ethanol concs

compare the processes of fermentation and hydration: