Introduction
Sodium sulfide is pink to yellowish solid with a rotten egg-like
odor. It is readily soluble in water, slightly soluble in alcohol
and insoluble in ether. Anhydrous sodium sulfide can ignite spontaneously
when exposed to air.
[¹]
It is
used in chemical manufacturing as a sulfonation and sulfomethylation
agent. It is used in the production of rubber chemicals, sulfur
dyes, and other chemical compounds. It has also been used as a reducer
for the reduction of nitro compounds to the corresponding amines.
[²]
It was found to be useful
for the conversion of carboxylic acids into thioacids
[³]
and alkenoyl ketene dithioacetals
into the corresponding [5+1]-annulation
products
[4]
as well as for the synthesis
of thiofuranose,
[5]
cyclic dithiocarbonates,
[6]
tetrahydrothiophene derivatives,
[7]
4-bromo-2-nitrobenzenethiol,
[8]
a-lipoic acid,
[9]
thieno[2,3-c]pyrazoles,
[¹0]
unsaturated thiacrown
ethers,
[¹¹]
thieno[3,2-c]cinnoline,
[¹²]
monomeric cyclic
diketosulfides,
[¹³]
thiophenes,
[¹4]
2H-thiopyran
compounds,
[¹5]
4H-thiochromen-4-ones
[¹6]
and benzo[b]thiophenes.
[¹7]
It can also act as an
atom-economical inorganic nucleophile in transition-metal-catalyzed
allylation substitutions.
[¹8]
Willgerodt-Kindler
reaction between anilines and benzaldehydes has also been achieved by
the use of Na2S˙9H2O as a base catalyst.
[¹9]
Sodium sulfide is commercially available and it can be readily
prepared by reduction of Na2SO4 with carbon
or through a solid-gas reaction of a sulfidizing gas mixture of
COS, CS2, and S2 with the reactant of Na2CO3.
[²0]
