In chemistry, disulfate or pyrosulfate is the
anion
An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conven ...
with the molecular formula . Disulfate is the IUPAC name.
It has a
dichromate-like structure and can be visualised as two corner-sharing SO
4 tetrahedra, with a bridging oxygen atom.
[ ]
In this anion, sulfur has an
oxidation state
In chemistry, the oxidation state, or oxidation number, is the hypothetical Electrical charge, charge of an atom if all of its Chemical bond, bonds to other atoms are fully Ionic bond, ionic. It describes the degree of oxidation (loss of electrons ...
of +6. Disulfate is the
conjugate base of the hydrogen disulfate (hydrogen pyrosulfate) ion , which in turn is the conjugate base of
disulfuric acid
Disulfuric acid (alternative spelling disulphuric acid) or pyrosulfuric acid (alternative spelling pyrosulphuric acid), also named oleum, is a sulfur oxoacid. It is a major constituent of fuming sulfuric acid, oleum, and this is how most chemists e ...
(pyrosulfuric acid).
Role in sulfation
Industrial production of
sulfate ester
In organosulfur chemistry, organosulfates are a class of organic compounds sharing a common functional group with the structure . The core is a sulfate group and the R group is any Organyl group, organic residue. All organosulfates are formally ...
-based surfactants involves the reaction (
sulfation) of
fatty alcohol
Fatty alcohols (or long-chain alcohols) are usually high-molecular mass, straight-chain primary alcohols, but can also range from as few as 4–6 carbon atoms to as many as 22–26, derived from natural fats and oils. The precise chain length vari ...
s with
sulfur trioxide. For example,
dodecyl alcohol is sulfated using
sulfur trioxide. The reaction proceeds by initial formation of the pyrosulfate:
:
:
Several million tons are produced annually.
See also
*
Potassium pyrosulfate
Potassium pyrosulfate, or potassium disulfate, is an inorganic compound with the chemical formula K2S2O7.
Production
Potassium pyrosulfate is obtained by the thermal decomposition of other salts, most directly from potassium bisulfate:
: 2 KHSO4 ...
*
Sodium pyrosulfate
*
Pyrophosphate
*
Pyrocarbonate
References
{{reflist
Sulfur oxyanions