Pine tar

When tar is the viscous, non- water-soluble mixture of organic substances, which, in addition to charcoal, wood gas, wood vinegar and water, produced during the pyrolysis of wood.

History

Tar has long been used in wood shipbuilding for the preservation of wood and rope. Networks used in salt water were also impregnated with tar. Even as a lubricant he had been in use, such as hammer mills. Today it is used mainly in the form of beech wood - not to be confused with tar book - as an attractant for wild boar and deer wallows in use.

Production

If wood, so pyrolyzed under exclusion of air in a closed container above about 250 ° C and heated higher, to decompose the substances charcoal, wood tar, wood vinegar and wood gas begins. Until the charcoal all substances are gaseous at the high temperature. Upon cooling to ambient temperature condense tar and wood vinegar and only the wood gas is gaseous. The wood vinegar comprises the water produced in the pyrolysis, and the organic substances dissolved in it, such as methanol, formic acid, acetic acid and phenol. The tar contains the water-insoluble organic substances. Both fluids are not miscible; the wood vinegar floats on top.

Will not heat from the outside you, you can let flow a little air into the container so that the wood burns incompletely ( smoldering ) and thus heats itself. Under such conditions, which correspond to those of a wood gasification, the oxygen with the organic tar and wood vinegar substances react. Its properties and composition are then in contrast to the pure pyrolysis and are almost identical to those of the wood gas condensate.

Properties

Tar is a good combustible mixture of different substances with different boiling points. Were obtained during the manufacture and the materials with comparatively low boiling point, then the tar liquid ( not viscous ), pungent odor of smoke and has a brown color. If you leave the tar are open, it is always viscous to solid by evaporation and further chemical reactions of organic substances to light and air. The tar is then almost black and tight, such as plasticine. The aromatic smell of smoked sausage and meat products derived from these materials.

See also

• Tar
• Pitch oil stone
• Birch pitch
• Pecherei