Phosphorus pentasulfide is the inorganic
compound with the formula P4S10. This yellow solid is the
one of two phosphorus sulfides of commercial value. Samples often appear
greenish-gray due to impurities.
In
organic chemistry P4S10 is used as a thionation reagent.
Reactions of this type require refluxing solvents such as benzene, dioxane or
acetonitrile with P4S10 dissociating into P2S5.
P2S5 can be trapped for example as the pyridine complex.
Ketones are converted to thioketones. In esters, imides and lactones the oxygen
atom can also be replaced by sulfur. With amides the reaction product is a
thioamide. With 1,4-diketones the reagent forms a thiophene. Compared to the
better known Lawesson's reagent P4S10
suffers from reduced yields. (Wikipedia)
Chemicals
1.
Red
phosphorus (pre-dried) : 1.6722 g
2.
Sulfur
(resublimed) : 4.3278 g
Apparatus
1.
A
Hot plate
2.
A
crucible with a cover
3.
Spatula
4.
Mortar
and pestle
Procedure
1.
Add
1.6722g red phosphorus powder and 4.3278 g resublimed sulfur in a crucible (with
a cover).
2.
Heat
the crucible genteelly to about 300℃[1] and leave it for 5 minutes.
3.
Cool
the crucible in a desiccator.
4.
Scratch
the solid from the crucible and smash it into powder with a mortar and pestle.[2]
It is a greenish-yellow powder
5.
Preserve
it in an air-tight vessel.
Notes
[1]
Don’t open the cover before you cool the crucible to room temperature or it may
cause fire and produce toxic gases. Once it burns, use dry sand or dry powder extinguisher.
Don’t use water to extinguish fire or it may cause explosion.
[2]
This procedure must be done in a hood or a ventilate area. If high
concentration of hydrogen sulfide (with an odor of rotten egg) is inhaled, it
will rapidly absorbed through the lung into blood. It may cause coma and may be
rapidly fatal.
[3]
This product is highly flammable and very toxic to aqueous organisms
[4]
Must see the MSDS of phosphorus pentasulfide before you handle it.
Experimental
Record
Weight
of Phosphorus Pentasulfide
|
4.4102
g
|
Theoretical
Weight of Phosphorus Pentasulfide
|
6.0000
g
|
Yield
|
(4.4102
g) / (6.0000 g) x 100%
|
=
73.50%
|
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