Studied by 7 people
What are the 2 ways that alcohols can be produced?
Hydration, fermentation
General formula for alcohols
CnH2n+1OH
What catalyst and temperature is needed for hydration to make alcohols?
Phosphoric acid (H3PO4), 300°C
Equation for production of ethanol by hydration
ethene + water —> ethanol
How is ethanol made by fermentation?
Enzymes break down starch from crops into sugar which can then be fermented to for ethanol
Why is the fermentation method to make ethanol carbon neutral?
The CO2 given out when it is burned is taken in by plants during photosynthesis (net carbon output is 0)
Equation for production of ethanol by fermentation
C6H12O6 —> C2H5OH + CO2
What enzyme is needed to convert glucose to ethanol?
Yeast
What are disadvantages of production of ethanol by fermentation?
Slower and lower percentage yield
Why is fermentation cheaper than hydration?
It takes place at lower temperatures
What types of alcohols can be oxidised?
1° and 2°
Why can 3° alcohols not be oxidised?
C-C bond would have to be broken rather than C-H bond
What oxidising agent is needed for oxidation of primary alcohols?
Acidified potassium dichromate (Cr2O7 2-)
Equation for partial oxidation of 1° alcohols (example propanol)
Propan-1-ol + [O] —> propanal + H2O
Equation for full oxidation of primary alcohols (example propanol)
Propan-1-ol + 2[O] —> propanoic acid + H2O
What colour change is observed when oxidising alcohols using acidified potassium dichromate?
Orange to green
What is produced when you oxidise a secondary alcohol?
Ketone
what are the conditions needed for oxidation of secondary alcohols?
Potassium dichromate, heat under reflux
Equation for oxidation of secondary alcohols (example propanol)
Propan-2-ol + [O] —> Propanone + H2O
Why should you never seal the end of the condenser during reflux?
Build up of gas pressure can cause the apparatus to explode
Why are anti-bumping granules added to the flask in reflux and distillation?
To prevent vigorous, uneven boiling by making small bubbles form instead of large bubbles
