Sulfonic acid is
a compound with general formula RSO2OH, where R is an
aliphatic or aromatic hydrocarbon. It is a derivative of sulfuric acid
(HOSO2OH) where an OH has
been replaced by a carbon group or a compound where a hydrogen atom has been
replaced by treatment with sulfuric acid; for example, benzene is converted to
benzenesulfonic acid (water-soluble). Sulfonic acid has a sulfur atom bonded to
a carbon atom of a hydrocarbon and bonded also to three oxygen atoms, one of
which has been attached to a hydrogen atom.
Sulfonic acid is acidic due to the
hydrogen atom, stronger than a carboxylic acid. Sulfonic acid is one of the most
important organo sulfur compounds in organic synthesis. Sulfonic acids are used
as catalysts in esterification, alkylation and condensation reactions.
Sulfonates are salts or esters of sulfonic acid. Sulfonic salts are soluble in
water. Sulfonic acid and its salts present in organic dyes provide useful
function of water solubility and or improve the washfastness of dyes due to
their capabiltity of binding more tightly to the fabric.
Toluenesulfonate esters are useful for the application as alkylating agents in
organic synthesis. p-Toluenesulfonic acid is used as a non-oxidizing catalyst
in the manufacture of plasticizers It is used as a curing agent for
epoxy-phenolic resins. Toluene sulfonic acids are used in preparing hydrazine
based blowing agents such as p-Toluenesulfonylhydrazide, p,p'-Oxybis(benzenesulfonylhydrazide), p-Toluenesulfonyl acetone hydrazone. Toluene
sulfonic acids and their derivatives are used as intermediates for the synthesis of isocyanate
compounds used as water scavengers and catalysts for the production of
thermosetting resins. They are synthetic intermediates for a number of
biologically active compounds, pharmaceuticals, herbicides, dyes and pigments candidates.
sulfonic acid is often used as a catalyst in the formation of acetal which water must be removed from the reaction mixture to
escape reversible reaction. Water is removed azeotropically
by distilation. (Toluene is the solvent).
is a white to
light gray powder; insoluble in water, chorobenzene, slightly
soluble in hot
water, soluble in alkaline solution, ethyl alcohol and ether.
It is used as an intermediate for the synthesis
of organic colorants; pigments (red color),
dyes, optical brighteners; printing inks.
(6-Amino-m-toluenesulfonic acid, CAS #: 88-44-8) is