Pyroligneous acid

Wood vinegar (Latin Acetum lignorum or also Acidum pyrolignosum ) is the liquid condensate of wood gasification.

Properties

Wood Vinegar consists of about 12 % acetic acid and homologues, 2% methanol, 1 % acetone, methyl acetate 1% and 10 % dissolved tar.

The crude wood vinegar, brown, sour, unpleasant tarry and smoky smelling and tasting liquid, is next to water from acetic acid, wood alcohol and small amounts of creosote, fire resins and fire oils, aldehyde and other products of the distillation, the only play the role of impurities here.

Production

When wood is subjected to the type of gas coal dry distillation, it leaves the same about 20-30 % carbon and the aborted products of distillation are some real gases ( coal gas ), some vapors of liquids that are condensed form droplets again by cooling templates created depending on the volatility wood vinegar and tar, which occupies the bottom place in the distillate.

In the carbonization of wood after hergebrachter way in kilns the wood gases, the wood vinegar and water vapor go into the air and partially burn; contrast is obtained in wood gas factories wood gas. Even with the charcoal, the distillation method is used in the actual carbon distillery used in place of Meilerverkohlung, which won the wood vinegar and tar and occurring gas is thus still reasonably used that one directs it into the retort and can burn with. By slurrying of milk of lime, the acid can be neutralized and bound, thereby wood spirit settles above. The production of wood alcohol was used in the 19th century, as in wood alcohol was less volume to transport with ease of handling. From the dried Essigkalk acetic acid could be obtained. Most of the acetic acid, the distillate of beech and birch wood. In general, the content of 5-9 % acetic acid changes. The preparation of pure acetic acid and wood alcohol was operated late 19th century on a large scale.

Use

The crude wood vinegar is used for as a rot retardant, also probably moths and other insects abhaltendes paints, for the preservation of wood and basting meats (cold smoked ).

For dyeing and printing has the same good use in preparing the necessary to ensure that certain colors wood acetic acid iron, also it serves instead of ordinary vinegar for the production of sugar of lead, aluminum acetate and other preparations.

By Umdestillieren of crude wood vinegar in the way that only three-quarters will be deducted from the whole, we obtain the purified or rectified wood vinegar which is prescribed in medicine, but is still not a pure vinegar, because the same smell still dicey and loses under the influence of air and light its initial colorless again by him nor stain the indwelling fuels with oxygen intake and let the liquid appear yellowish or brownish.