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org14 Molecule
structure and properties of butanole isomers
*
Sodium is very corrosive. *Experiment with a chemstry teacher. Use
a tray. * So not forget your goggles!
Left: Add a tiny
piece of sodium into bottles with of primary, secondary and teriary
butanole.
Middle: Mix
1 ml samples of water with 1 ml of primary, secondary and teriary
butanole.
Observations
left:Tertiary
butanole shows nearly no reaction with sodium, secondary butanole reacts
more significant , primary butanol reacts best (a residue floats).
Middle: Tertiary
butanole dissolves well in water, primary butanole (longest C4H9-chain)
has lowest solubility.
Explanations
using molecule models right:
All butanole molecules consist
of a a hydrocarbon component (C4H9-) and of a hydroxyle
group (-OH). The models show the different structures of both components.
The OH group
reacts with sodium like the same goup in a water molecule (H-OH) releasing
hydrogen:2 C4H9-OH(l)
+ 2 Na(s) ----> 2 C4H9-ONa + H2(g).In
tertiary butanole the OH group is surrounded by three CH3 goups. So
sodium particles cannot easily collide with the OH group: limited hydrogen production.
The different solubility
of butanoles in water is related to the different shapes of
the C4H9 groups: In primary butanole these are long
chains which make the alcohol molecules "sticky": They cannot easily be
separated by water molecules to mix with them.
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modification: 16.04.2003