TAR is a dark brown or black viscous liquid of hydrocarbons and free
carbon , obtained from a wide variety of organic materials through
destructive distillation .
Tar can be produced from coal , wood ,
petroleum , or peat . Production and trade in pine-derived tar was a
major contributor in the economies of
Northern Europe and Colonial
America . Its main use was in preserving wooden sailing vessels
against rot. The largest user was the
Royal Navy . Demand for tar
declined with the advent of iron and steel ships.
Tar-like products can also be produced from other forms of organic
matter , such as peat . Mineral products resembling tar can be
produced from fossil hydrocarbons , such as petroleum.
Coal tar is
produced from coal as a byproduct of coke production.
Bitumen is a
term used for natural deposits of oil "tar", such as at the La Brea
Tar Pits .
* 1 Terminology
* 2.1 Uses
* 4 See also
* 5 References
* 6 External links
"Tar" and "pitch " can be used interchangeably; asphalt (naturally
occurring pitch) may also be called either "mineral tar" or "mineral
pitch". There is a tendency to use "tar" of more liquid substances and
"pitch" of more solid (viscoelastic ) substances. Both "tar" and
"pitch" are applied to viscous forms of petroleum or heavy crude oil ,
technically better described as asphalt or bitumen , such as the
asphalt found in naturally occurring "tar pits " (e.g., the La Brea
Tar Pits in Los Angeles) and oil sands deposits (sometimes called "tar
sands") (e.g., the
Tar Tunnel in Shropshire). "Rangoon tar", also
known as "Burmese Oil" or "Burmese Naphtha", is also a form of
Pine tar and
Tar kiln at
Öland , Sweden.
Northern Europe , the word "tar" refers primarily to a substance
that is derived from the wood and roots of pine . In earlier times it
was often used as a water repellent coating for boats , ships , and
roofs . It is still used as an additive in the flavoring of candy ,
alcohol , and other foods.
Wood tar is microbicidal . Producing tar
from wood was known in ancient Greece and has probably been used in
Scandinavia since the
Iron Age . For centuries, dating back at least
to the 14th century, tar was among
Sweden 's most important exports.
Sweden exported 13,000 barrels of tar in 1615 and 227,000 barrels in
the peak year of 1863. Production nearly stopped in the early 20th
century, when other chemicals replaced tar, and wooden ships were
replaced by steel ships. Traditional wooden boats are still sometimes
The heating (dry distilling ) of pine wood causes tar and pitch to
drip away from the wood and leave behind charcoal.
Birch bark is used
to make particularly fine tar, known as "Russian oil", suitable for
leather protection. The by-products of wood tar are turpentine and
charcoal . When deciduous tree woods are subjected to destructive
distillation, the products are methanol (wood alcohol) and charcoal .
TAR KILNS (Swedish : tjärdal, Danish : tjæremile, Norwegian :
tjæremile, Finnish : tervahauta) are dry distillation ovens,
historically used in
Scandinavia for producing tar from wood. They
were built close to the forest, from limestone or from more primitive
holes in the ground. The bottom is sloped into an outlet hole to allow
the tar to pour out. The wood is split into dimensions of a finger,
stacked densely, and finally covered tight with dirt and moss. If
oxygen can enter, the wood might catch fire, and the production would
be ruined. On top of this, a fire is stacked and lit. After a few
hours, the tar starts to pour out and continues to do so for a few
Birch-tar Tar-flavored candy,
Terva Leijona .
Tar was used as seal for roofing shingles and tar paper and to seal
the hulls of ships and boats. For millennia, wood tar was used to
waterproof sails and boats, but today, sails made from inherently
waterproof synthetic substances have reduced the demand for tar. Wood
tar is still used to seal traditional wooden boats and the roofs of
historical shingle-roofed churches, as well as painting exterior walls
of log buildings.
Tar is also a general disinfectant.
Pine tar oil, or
wood tar oil, is a pure natural product used for the surface treatment
of wooden shingle roofs, boats, buckets, and tubs and in the medicine,
soap, and rubber industries.
Pine tar has good penetration on the
rough wood. An old wood tar oil recipe for the treatment of wood is
one-third each genuine wood tar, balsam turpentine, and boiled or raw
linseed oil or Chinese tung oil.
Finland , wood tar was once considered a panacea reputed to heal
"even those cut in twain through their midriff". A Finnish proverb
states that "if sauna , vodka and tar won't help, the disease is
Wood tar is used in traditional Finnish medicine because of
its microbicidal properties.
Wood tar is also available diluted as tar water , which has numerous
* As a flavoring for candies (e.g.,
Terva Leijona ) and alcohol
* As a spice for food, like meat
* As a scent for saunas .
Tar water is mixed into water, which is
turned into steam in the sauna
* As an anti-dandruff agent in shampoo
* As a component of cosmetics
Mixing tar with linseed oil varnish produces tar paint.
Tar paint has
a translucent brownish hue and can be used to saturate and tone wood
and protect it from weather.
Tar paint can also be toned with various
pigments, producing translucent colors and preserving the wood
In English, German, and French, "tar" is a substance primarily
derived from coal. It was formerly one of the products of gasworks .
Tar made from coal or petroleum is considered toxic and carcinogenic
because of its high benzene content, though coal tar in low
concentrations is used as a topical medicine.
Coal and petroleum tar
has a pungent odour.
Coal tar is listed at number 1999 in the United Nations list of
dangerous goods .
Pitch drop experiment
Tarring and feathering
Tar (tobacco residue)
* tar (computing)
* ^ Daintith, John. "tar". Oxford University Press (6th ed.). A
dictionary of chemistry. Retrieved 14 March 2013. "Tar: Definition".
Miriam Webster. Retrieved 14 March 2013. "a dark brown or black
bituminous usually odorous viscous liquid obtained by destructive
distillation of organic material (such as wood, coal, or peat)". "tar
and pitch" (6th ed.). The Columbia Electronic Encyclopedia. Retrieved
14 March 2013. "tar and pitch, viscous, dark-brown to black
substances obtained by the destructive distillation of coal, wood,
petroleum, peat, and certain other organic materials. "
* ^ Burger, Pauline. "Ancient maritime pitch and tar a
multi-disciplinary study of sources, technology and preservation".
British Museum. Retrieved 14 March 2013.
* ^ "tar and pitch" (6th ed.). The Columbia Electronic
Encyclopedia. Retrieved 14 March 2013. "The terms tar and pitch are
loosely applied to the many varieties of the two substances, sometimes
interchangeably. For example, asphalt, which is naturally occurring
pitch, is called mineral tar and mineral pitch.
Tar is more or less
fluid, depending upon its origin and the temperature to which it is
exposed. Pitch tends to be more