ORGANIC CHEM - ALCOHOLS Flashcards
How are alcohols produced?
hydration of alkenes with an acid catalyst (electrophilic addition)
How can ethanol be produced?
- hydration of ethene in the presence of an acid catalyst
- fermentation
What is the equation for fermentation?
C6H12O6 -> 2C2H5OH + 2CO2
What is a biofuel?
a fuel derived from living matter (eg: ethanol produced from the fermentation of glucose)
What does carbon neutral mean?
no net emissions of CO2 to the atmosphere
Why is bioethanol being used as a fuel considered carbon neutral?
the amount of CO2 released when it’s burned is the same amount of CO2 that is absorbed by plants for photosynthesis
Why is the claim that bioethanol is carbon neutral incorrect?
doesn’t take into account CO2 released from other things like transporting the bioethanol
What is a primary alcohol?
C atom bonded to the hydroxyl (-OH) group is attached to only one other C atom
What is a secondary alcohol?
C bonded to the hydroxyl (-OH) group is attached to 2 other C atoms
What is a tertiary alcohol?
C bonded to the hydroxyl (-OH) group is attached to 3 other C atoms
Elimination by dehydration of an alcohol:
- reagent?
- conditions?
- what happens?
- reagent: H2SO4
- conditions: hot, conc. H2SO4, 180°C
- alcohol is dehydrated (loses H2O) to form an alkene
What is used to oxidise alcohols?
acidified potassium dichromate (K2Cr2O7 + H2SO4)
Primary alcohol + [O] -> ?
aldehyde + H2O
Aldehyde + [O] -> ?
carboxylic acid
Primary alcohol + 2[O] -> ?
carboxylic acid + H2O
Secondary alcohol + [O] -> ?
ketone + H2O
What is used to convert primary alcohols to aldehydes?
distillation
What is used to convert primary alcohols to carboxylic acids?
reflux
Things to include in a distillation diagram
- round-bottomed/pear shaped flask
- bung and thermometer at the top of the flask
- acidified potassium dichromate
- heat source
- condenser going into a conical flask
- water going in at the bottom of the condenser and out at the top
Things to include in a reflux diagram
- round-bottomed/pear shaped flask
- acidified potassium dichromate
- heat source
- vertical condenser which should be open at the top
- water going in at the bottom of the condenser and out at the top
