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Benzoic acid, the
simplest aromatic carboxylic acid containing carboxyl group bonded
directly to benzene ring, is a white, crystalline organic compound;
melting at 122 C (starting sublime at 100 C); boiling at 249 C;
slightly soluble in water, soluble in ethanol, very slightly soluble in
benzene and acetone. Its aqua solution is weakly acidic. It occurs
naturally in many plants and resins. Benzoic acid is also detected
in animals. The most of commercial benzoic acid is produced by the
reaction of toluene with oxygen at temperatures around 200 C in the
liquid phase and in the presence of cobalt and manganese salts as
catalysts. It can be prepared also by the oxidation of benzene with
concentrated sulphuric acid or carbon dioxide in the presence of
catalysts. Other methods are such as by the oxidation of benzyl alcohol,
benzaldehyde, and cinnamic acid; by hydrolysis of benzonitrile, benzoyl
chloride. More than 90% of commercial benzoic acid is converted directly
to phenol and caprolactam. Its use in the production of glycol benzoates
for the application of plasticizer in adhesive formulations is
increasing. It is also used in the manufacture of alkyd resins and
drilling mud additive for crude oil recovery applications. It is
used as a rubber polymerization activators and retardants. Benzoic acid
is converted to its salts and esters for the use of preservative
application in foods, drugs and personal products. Sodium benzoate,
sodium salt of benzoic acid, is used preferably as one of the principal
anti-microbial preservatives used in foods and beverages (but it's
concentration is limited usually not exceeding 0.1% because it is
poisonous), as it is about 200 times more soluble than benzoic acid.
Sodium Benzoate is also used in medications, anti-fermentation additives
and tabletting lubricant for pharmaceuticals. The industrial applications
are as a corrosion inhibitor, as an additive to automotive engine
antifreeze coolants and in other waterborne systems, as nucleating agents
for polyolefin, as a dye intermediate, as a stabilizer in photographic
processing and as a catalyst. Wide range of benzoic esters is used
as solvents, dying carrier, and disinfectant additive, penetrating agent
and pesticides and manufacturing other compounds.
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