Styphnic acid (from
Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
''stryphnos'' "astringent"
[Alexander Senning (2006). ]), or 2,4,6-trinitro-1,3-benzenediol, is a yellow
astringent
An astringent (sometimes called adstringent) is a chemical that shrinks or constricts body tissues. The word derives from the Latin ''adstringere'', which means "to bind fast". Calamine lotion, witch hazel, and yerba mansa, a Californian pla ...
acid that forms hexagonal
crystal
A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macro ...
s. It is used in the manufacture of
dyes,
pigment
A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compou ...
s, inks, medicines, and
explosives such as
lead styphnate
Lead styphnate (lead 2,4,6- trinitroresorcinate, C6HN3O8Pb ), whose name is derived from styphnic acid, is an explosive used as a component in primer and detonator mixtures for less sensitive secondary explosives. Lead styphnate is only slightly ...
. It is itself a low sensitivity explosive, similar to
picric acid, but explodes upon rapid heating.
Preparation and chemistry
It may be prepared by the nitration of
resorcinol
Resorcinol (or resorcin) is an organic compound with the formula C6H4(OH)2. It is one of three isomeric benzenediols, the 1,3-isomer (or '' meta''-isomer). Resorcinol crystallizes from benzene as colorless needles that are readily soluble i ...
with a mixture of
nitric and
sulfuric acid.
This compound is an example of a trinitro
phenol
Phenol (also called carbolic acid) is an aromatic organic compound with the molecular formula . It is a white crystalline solid that is volatile. The molecule consists of a phenyl group () bonded to a hydroxy group (). Mildly acidic, it ...
.
Like
picric acid, it is a moderately strong acid, capable of displacing carbon dioxide from solutions of
sodium carbonate, for example.
It may be reacted with weakly basic oxides, such as those of lead and silver, to form the corresponding salts.
The solubility of
picric acid and styphnic acid in water is less than their corresponding mono- and di-nitro compounds, and far less than their non-nitrated precursor phenols, so they may be purified by fractional crystallisation.
References
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Nitrophenols
Explosive chemicals
Resorcinols
Organic acids