4.6 + 6.5 - Organic synthesis Flashcards
1
Q
Name the basic quick fit apparatus
A
- round-bottom/pear-shaped flask
- receiver
- screw-tap adaptor
- condensor
- still head
2
Q
Describe the safest heating method for reflux, other precautions and why
A
- heating mantle
no naked flame = safer if apparatus leaks/cracks - anti-bumping granules added to liquid
so boils smoothly - glass joints lightly greased
so apparatus comes apart easily after experiment - condensers clamped loosely
outer jacket very fragile - never put stopper in top
closed system = pressure builds up and explodes
3
Q
Purpose of reflux
A
to heat volatile organic compounds to prepare organic product without boiling off solvent, reactants or products
4
Q
Purpose of distillation
A
to separate pure liquid from its impurities
5
Q
Give precautions of distillation
A
- glass joints lightly greased
so apparatus comes apart easily after experiment - flask to collect distillate
so not airtight - separate product at end to prevent further oxidation (e.g primary alcohol -> aldehyde -> carboxylic acid)
6
Q
Describe how to purify an organic product (stage 1: separating funnel)
A
- use separating funnel to separate organic and aqueous layers
- collect organic layer
(densest is bottom, less dense is top)
7
Q
Describe how to purify an organic product (stage 2: drying)
A
- add organic liquid to conical flask and dry by adding anhydrous salt (e.g CaCl2, CaSO4, MgSO4, hydrocarbons) with spatula and swirl
- place stopper on to prevent product evaporation and leave for 10 mins
- decant liquid into another flask
8
Q
Describe how to purify an organic product (stage 3: redistillation )
A
collect product at fraction of exact boiling point of desired product in redistillation
9
Q
What does BP range tell you about product purity?
A
narrower range = purer product
10
Q
Describe how to purify an organic solid
A
- filter under reduced pressure
- recrystallise
- measure MP
