Description of experiment
Below follows a plain text transcript of the selected experiment.
Needed compounds:
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acetone : CH3 CO CH3
sulphuric acid : H2SO4
methyl ethyl ketone : CH3 CO CH2 CH3
Class:
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elem=C
organic
Summary:
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MEK reacts with sulphuric acid. A quick reaction occurs when the liquids
are mixed and a lot of heat is produced. Further reaction takes a few days.
The second reaction stage results in formation of a oil-like product
(a polymerization product?).
Description:
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Sequence 1:
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Add 1 volume of H2SO4 (appr. 98% by weight) to 4 volumes of MEK: The acid
completely dissolves in/mixes with the MEK (requires some shaking). After
dissolving/mixing, the liquid has become hot. The liquid is colourless.
After appr. 12 hours, the liquid is red/orange. After appr. 1.5 day, the
liquid is dark red/brown. After 3 days the liquid is almost black. At that
time, two layers can be observed. A thin colorless layer floats on top of
a thick viscous black layer. When the container is swirled, then the dark
liquid sticks to the glass, leaving a dark red/brown layer on the glass.
Pour the liquid (both the thick black layer and the thin colorless layer)
in a beaker, containing a large excess amount of water: The water becomes
turbid and yellow (what is the yellow precipitate?). Dark drops are floating
on the surface of the water. When the liquid is shaken, then the dark drops
dissolve in the water and they disappear. When the liquid is allowed to
stand for a while, then a brown layer is formed on the surface of the water.
Pour the complete liquid out of the beaker (turbid water and brown stuff):
The glass is covered with a oil-like substance, contaminated with remnants
of the yellow precipitate. The oil-like substance is hard to remove. Rinsing
with water multiple times does not result in removal of the substance from
the glass (with some acetone, however, the substance can easily be removed,
it dissolves in acetone).
A strong smell can be observed during these experiments. The smell is pungent
and spicy. (smell, resemling a certain plant / leather like?).
Sequence 2:
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Add 1 volume of MEK to two volumes of sulphuric acid (96%). CAUTION: The MEK
is added very carefully in small quantities at a time and between two
quantities the mixture is allowed to cool down before a new portion is added:
A lot of heat is produced, each time some MEK is added. When the mixture is
shaken, all MEK dissolves in the acid. After all MEK is added, the liquid
is colourless. After one day of standing, the mixture has become yellow.
After 3 days, the mixture is orange/red, like the colour of bromine-water.
On top of the orange/red liquid there is a thin layer of an almost colourless
liquid. The orange/red liquid is very viscous, oil-like.
Above the liquid, a clear smell of sulphur dioxide can be observed, together
with another familiar smell (some plant?).
Pour the liquid (both layers) in a large quantity of water: As soon as the
liquid(s) come in contact with the water, a yellow/white milk-like liquid
is formed. The color of this liquid is less intense than the turbid liquid,
formed from the black oil-like liquid from sequence 1. The other aspects,
observed in sequence 1, are observed here as well, including the special
smell.