Uses of Hydrogen sulfide

Production of thioorganic compounds

Several organosulfur compounds are produced using hydrogen sulfide.
These include methanethiol, ethanethiol, and thioglycolic acid.

Alkali metal sulfides

Upon combining with alkali metal bases, hydrogen sulfide converts
to alkali hydrosulfides such as sodium hydrosulfide and sodium sulfide,
which are used in the degradation of biopolymers. The depilation of
hides and the delignification of pulp by the Kraft process both are
effected by alkali sulfides.

In analytical chemistry

Hydrogen sulfide used to have importance in analytical chemistry
for well over a century, in the qualitative inorganic analysis of metal
ions. For such small-scale laboratory use, H2S was made as needed in a
Kipp generator by reaction of sulfuric acid (H2SO4) with ferrous
sulfide FeS. Kipp generators were superseded by the use of
thioacetamide, an organic solid that converts in water to H2S. In these
analyses, heavy metal (and nonmetal) ions (e.g. Pb(II), Cu(II), Hg(II),
As(III)) are precipitated from solution upon exposure to H2S. The
components of the resulting precipitate redissolve with some
selectivity.

A precursor to metal sulfides

As indicated above, many metal ions react with hydrogen sulfide to
give the corresponding metal sulfides. This conversion is widely
exploited. In the purification of metal ores by flotation, mineral
powders are often treated with hydrogen sulfide to enhance the
separation. Metal parts are sometimes passivated with hydrogen sulfide.
Catalysts used in hydrodesulfurization are routinely activated with
hydrogen sulfide, and the behavior of metallic catalysts used in other
parts of a refinery is also modified using hydrogen sulfide.

Miscellaneous applications

Hydrogen sulfide is also used in the separation of deuterium oxide,
i.e. heavy water, from normal water via the Girdler Sulfide process