Alcohols Flashcards
Name of reaction
Mechanism
Reagent & conditions
For alkene to alcohol
Dehydration
Elimination
Conditions :
- Concentrated H2SO4
- high pressure
Reagent : steam
Show how glucose can produce ethanol in a fermentation reaction
State conditions for this reaction
C6H12O6 -> 2CH3CH2OH + 2CO2
Conditions :
- Yeast catalyst
- No air
- temperature between 30 - 40 degrees
Why can’t fermentation have too low temperature or too high temperature
Too low : reaction to slow
Too high : yeast enzymes becomes denatured
What is meant by carbon-neutral
No net overall emissions of CO2 released into the atmosphere
How to show carbon as carbon neutral using photosynthesis, fermentation and combustion equations
Advantages and disadvantages of using ethanol in fermentation
Advantages and disadvantages of producing ethanol using direct hydration
O
Apparatus used to separate two immiscible liquids
Separating funnel
Reagent and conditions of oxidation of
Observation
a) primary alcohol to aldehyde
b) primary alcohol to carbolic acid
c) aldehyde to carboxylic acid
d) secondary alcohol to ketone
Reagent for all : acidified potassium dichromate
Ornate too green
a) heat under distillation
b) heat under reflex, excess oxidising agent
c) heat under reflux
d) heat under reflux or distillation
Both reflux and distillation apparatus use condenser, state use of condenser
Cools hot vapour and condenses it to liquid
Purpose of anti-bumping granules
Prevents formation of large bubbles
Draw a reflux apparatus, state what happens when aldehyde is in reflux, label parts of apparatus
Why is reflux used to oxidise primary alcohol to a carboxylic acid
Reflux doesn’t allow any reactant vapour to escape
- think about it like this, alcohol needs to keep boiling and boiling until forever to get to carboxylic acid as that can’t be further oxidised
Describe what happens when a reaction is refluxed and why it is necessary for complete oxidation to carboxylate acid, use ethanol as example of alcohol
Draw distillation apparatus, forget the part taking about aldehydes
What happens to aldehyde as it is produced during distillation
Aldehyde forms as a vapour and escapes from reaction mixture into condenser
Why is distillation used when producing aldehyde from primary alcohol
To prevent further oxidation
Outline mechanism for elimination but for an alcohol. Use example ethanol can be dehydrated to Ethene. Never mind its the Same mechanism works for all elimination of alcohols
What two watch out for when being asked to draw two isomeric alkenes
Don’t draw E-Z isomers, make sure you draw a position, functional or chain isomer
Nucleophilic substitution
Loss of H+ from 1st carbon in chain leads to but-1-ene
Loss of H+ from 3rd carbon in chain leads to but-2-ene
But-2-ene forms as e-z isomers
Tip : there was confusion on whether you had to draw sulfuric acid but you still get the mark using H+. Play safe and don’t use sulfuric acid
