Naphthols are
either of two crystalline monohydric alcohols, derived
from naphthalene and belonging to the phenol family. The naphthols are position isomers; Alpha-naphthol
(also called 1-naphthol) is 1-hydroxynaphthalene and Beta-naphthol (also called
beta-naphthol) is 2-hydroxynaphthalene. The compound 1-naphthol is made by heating 1-naphthalenesulfonic
acid with caustic alkali or by heating 1-naphthylamine with water under
pressure. The compound 2-naphthol is manufactured by fusing
2-naphthalenesulfonic acid with caustic soda. They are used directly in making
several dyes and are converted into numerous dye intermediates, as well as into
tanning agents, antioxidants, and antiseptics. 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been replaced by a carbon group or a compound where a hydrogen atom has been
replaced by treatment with sulfuric acid; for example, benzene is converted to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 capability of binding more tightly to the fabric. They are widely used in
the detergent industry. Alkylbenzene sulfonic acid is the largest-volume
synthetic surfactant because of its relatively low cost, good performance, the
fact that it can be dried to a stable powder and the biodegradable environmental
friendliness. Sulfonate cleaners do not form an insoluble precipitates in hard
water. Sulfonic acid salts and esters are intermediates widely used in organic
synthesis and particularly phenolic compounds and cation exchange resins. They
are synthetic intermediate for a number of biologically active compounds and
pharmaceutical candidates such as sulfa drugs. Short carbon chain metallic
sulfonate is used in electroplating which is a process for applying a metallic
coating on a metal surface by electrodeposition from a suitable electrolyte
solution for imparting corrosion resistance and direct production of printed
circuit boards without etching out of a piece of copper sheet.
J Acid (2-amino-5-naphthol-7-sulfonic Acid) is a brownish solid derived from
tobias acid ( 2-amino-1-naphthalene Sulfonic acid) or from beta-naphthalamine.
It is slight soluble in water but soluble in alcohol and ether. Its alkali salts
are freely soluble in water. J Acid turns dark brown in ferric chloride solution
whereas yellowish brown in calcium chloride. J acid family compounds such as
carbonyl J-acid, phenyl J-acid, benzoyl J-acid are used as intermediates for the
production of azo and direct dyes. |