Naphtha's price rise causes anxiety. It signals an inevitable increase
in polymer prices. So what is naphtha? Is it a compound? Naphtha
is a generic term applied to any one of a wide variety of volatile
hydrocarbon mixtures. They are obtained from coal tar or more often
from petroleum.
Petroleum naphtha or mineral naphtha is obtained from petroleum
as a crude distillate that is lighter than kerosene and has a lower
boiling point. It contains a mixture of methane-type hydrocarbons.
The distillates with lower boiling points than petroleum naphtha
are called ligroin. Other forms of naphtha are crude naphtha, obtained
from coal tar; shale naphtha, obtained from shale; and wood naphtha,
obtained from wood.
Solvent naphtha, used for dissolving rubber, is a high-boiling-point
fraction distilled from coal tar. Physical properties vary widely
depending on the mixture. Initial boiling point may may be as low
as 27°C and end points may reach as high as 260°C. Boiling
ranges could be as narrow as 11°C or as high as 110°C. In
the strictest sense of the term naphtha, not less than 10% of the
material should distill below 175°C and not less than 95% should
distill below 240°C. Strictly speaking refinery products like
gasoline and kerosene are also naphthas.
Naphthas are primarily produced by fractional distillation. Extractive
distillation is used when certain high quality naphthas are desired.
Acid, clay treating removes sulphur compounds and improves odour
and stability. Products sold as naphthas find their use as solvents,
thinners, or as carriers.
Naphthas could be classified between aliphatic (paraffinic) naphthas
and aromatic types. Aliphatic naphthas are relatively low in odor
and toxicity and low in solvent power. These are used in processing
of soyabeans for oil extraction, by dry cleaners, as a carrier in
printing inks. Aromatic naphthas are the high solvency type. The
main components are toluene and xylenes. These are used as thinners
for paints and varnishes. Rubber industry also uses naphtha as solvents.
Leather industry uses them to degrease the skin, metal industry
to degrease metals. naphthas also find usage in floor waxes, furniture
waxes, shoe polishes and metal polishes. And offcourse naphtha is
used in the manufacture of synthetic (artificial) resins. Pure naphtha
is highly explosive when exposed to an open flame.
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