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Method for Preparation of Bromoethane - Coggle Diagram
Method for Preparation
of Bromoethane
1.Place (10g)
NaBr
in
pear shaped flask
2.
Add
(7.5cm3) of
butan-1-ol
and (10cm3) of
water
Equation
3.Lower into beaker
of
cold water
why?
highly exothermic
reaction
4.Add (10cm3)
concentrated sulfuric acid
slowly + stirring
adding too fast =
dehydration of alcohol
5.Add
anti-bumping
granules
promote smooth
boiling
6.
Heat
under
REFLUX
for 30 mins
why heat?
organic reactions are slow
because covalent bonds are strong
why reflux?
to allow continuous evaporation and condensation without loss of product/reactant
7.
Distil
off product until
upper
organic layer gone
organic layer = mainly 1-bromobutane
with some other impurities:
water
unreacted butan-1-ol
sulfuric acid
hydrogen bromide
8.Place distillate in clean separating
funnel +
separate organic layer
Add small deionised water
layer INCREASES volume = aq layer
layer remains same volume = organic layer
9.Add
conc hydrochloric acid to
impure organic layer
in separating funnel
to
remove unreacted butan-1-ol
stopper
shake
invert (remove gas)
10.
Clamp
separating funnel +
allow
layers to separate
remove stopper (if not would be closed
system + layers not drain)
open tap
lower organic layer
run to beaker
upper aqueous layer
into other
layer + discard
11.Put
lower organic layer
in separating funnel
Wash
w/
sodium hydrogencarbonate solution
NaHCO3 = removes acidic impurities
of HBr + H2SO4
12.
Separate
as before +
discard upper
aqueous layer
SAFETY = invert + release gas
(CO2 formed in reaction)
13.Add
anhydrous sodium sulfate/calcium carbonate
- DRYING AGENT
14.
Decant
/filter to
remove
anhydrous sodium sulfate
15.
Distil
1-bromobutane
and collect at
101-103°C
why temp? boiling point
1-bromobutane is 102°C