Transcript Chem - Alcohols

Alcohols are soluble in water due
to the hydrogen bonding
between the extra hydrogen and
the water molecules. This leads
to lower volatility, because the
alcohol is less readily able to
disperse into a gas.
Fermentation is used to produce alcohol from
glucose. The glucose is produced by the hydrolysis
of starch. The conditions needed are: a warm
temperature, although this must not exceed 37
degrees Celsius & yeast to break down the sugars.
Equation: C6H12O6
2C2H5OH + 2CO2
Pros: Renewable energy resources are used; simple
equipment.
Cons: Slow; produces impure ethanol; has to be in
the batch process.
The hydration of ethene is used to make
alcohols by using fractions of distilled crude
oil from fractioning columns. It is made in
the presence of an acid catalyst, normally
phosphoric acid, and it needs high
temperature and pressure.
Equation: C2H4 + H2O
C2H5OH
Ethanol is used in alcoholic drinks, such as
beer, wine & spirits. It is also used as an
industrial solvent, when mixed with
methanol to make methylated spirits.
Finally, ethanol can be used as a fuel
substitute, in countries that have limited oil
resources.
Methanol can also be used in fuel, to
improve performance & combustion in
unleaded fuel. It can also be used as a
feedstock in important industrial processes.
However, be warned, methanol is highly
toxic.
In a primary alcohol, the carbon which
carries the -OH group is only attached
to one other carbon atom. Examples
include ethanol, propan-1-ol &
2-methylpropan-1-ol.
In a secondary alcohol, the carbon
with the -OH group attached is joined
to two other carbon atoms. Examples
are propan-2-ol, butan-2-ol &
pentan-3-ol
In a tertiary alcohol, the carbon atom
holding the -OH group is attached
directly to three carbon groups. Tertiary
alcohols are extremely hard to oxidise.
Examples, 2-methylpropan-2-ol &
2-methylbutan-2-ol.