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CHEMESTRY ⚗
ALCOHOLS
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Created by
Ixshel Garozzo
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Alcohols contain an
-OH
group and follow the general formula
CnH2n+1OH
Alcohols
can be produced via two main methods:
hydration
and
fermentation
Hydration method:
Alcohols are produced from
alkenes
in the presence of an
acid catalyst
Phosphoric acid is commonly used as the
catalyst
under
aqueous conditions
at
300°C
and
high pressures
Very high percentage yield as
ethanol
is the only product, favored as an
industrial process
Fermentation method:
Enzymes break down
starch
from
crops
into
sugars
which can be
fermented
to form
alcohol
Cheaper
than hydration, can be carried out at a
lower
temperature
Fermented in
batches
,
slower
process with a lower percentage yield
Ethanol
is a
common
biofuel produced in this way, considered
carbon neutral
Alcohols can be
primary
(
1o
),
secondary
(
2o
), or
tertiary
(
3o
)
1o and 2o alcohols can be
oxidised
to produce various
products
3o alcohols are not
easily
oxidised
1o alcohols can be heated in the presence of
acidified potassium dichromate
and distilled to produce
aldehydes
When heated further under reflux conditions, 1o alcohols
oxidise
further to produce
carboxylic acids
2o alcohols can be
oxidised
when
heated
in the presence of
acidified potassium dichromate
to produce
ketones
Potassium Dichromate
(
K2Cr2O7
) is used in the
oxidation
of
alcohols
as the
oxidising agent
It is
reduced
as the
alcohol
is
oxidised
, observed as a
colour change
from
orange
to
green
Alkenes can be formed from the
dehydration
of
alcohols
, where a molecule of
water
is
removed
from the molecule
Excess of
hot sulfuric acid
is added and
aluminium oxide
is used as a
catalyst
H+ acidic ions are reformed in the reaction showing how they act as a
catalyst
Addition
polymers can be produced from
fermentation
without the need for
crude oil
, a
nonrenewable
resource
Fermentation
produces the
primary alcohol
which is then
dehydrated
to produce an
alkene
used in the production of
addition polymers