The Mason County journal. [volume] (Shelton, W.T.) 1886-1927, 1889-11-15
USES OF COAL TAR.

Brilliant Colors Extracted From a sun.
stance Once Considered Worthless.
The coal tar created by gas MAKING
was for many years burned, together
with the coke, under the retorts Of
the gasworks. in order to economiza
coal; and not until Holman. a distin-
guished German chemist. investigated
coal tar scientifically was it found to
contain bodies that have since become
the basis of the worlds great color in
dustries. The brilliant aniline colors
now used for dyeing are all extracted
from coal. Coal tar yields, on redis.
tlllation. among other things a large
amount OF volatile oil called benzole.
Holman found that benzole. upon
proper treatment with certain chem.
icals, yielded aniline. This is an oilv
liquid. akin in its nature to the liouid
alkaloids. nicotine from tobacco and
CONNIE from hemlock. Holman also
succeeded in getting a beautiful deem
magenta dye from aniline by oxida-
ton, process in which a substance
called the oxidizer gives up some of
its oxygen to the body oxidized. This
dye he called rosaniline, and from il
may be obtained every conceivable
shade of color. 1t is a curious fact
this intense dye is colorless in an alb
solutely pure state, but on uniting
with acids it at once takes on it's char
acteristic vivid crimson color. Since
the most important part in the manu-
facture of these dyes depends upon
the oxidation of the aniline, it is neces-
sary to get some common and mex
pensive substance for that process.
Unfortunately for the personal COM
fort of many people. arsenic acid, one
OF our most fatal poisons, is the SUBJ
stance generally used. 1t is due to
this chemical that so many of the fab
RIGS dyed with aniline colors are in
furious. The dyes in themselves are
harmless. The arsenic acid is not es-
sential to the color, but after it has
done its duty as an oxidizer, the man.
ufacturer does not take the trouble to
remove the poison carefully from the
dyes. The suggestion to use other
oxidizers that are harmless has often
been made, but arsenic acid is in such
general use that manufacturers are
unwilling to give it up.
1t is said of Hoimann's discovery
no hn Of o1
had been trying the action of aniline
with different chemicals, and without
cleaning his test tubes had left them
standing in the rack. The next day,
upon his return to the laboratory, he
found, to his joy and establishment,
that something quite unexpected had
taken place. Beautiful crystals of a
deep magenta color had formed during
the night in one of the test tubes.
With eagerness' he examined them.
but could not remember how they had
been formed. At last it occurred to
him that this was the result of the OK
idation of aniline. This was the be-
ginning of Hefmann's great work upon
rOsaniline.
1t has also been discovered that
another body contained in coal tar can
be converted into one of the most i'm
portant and beautiful vegetable dyes
known - the dyeing matter of the
madden plant (alizarine), and since
the discovery the prices of madden
are so low that it is unremunerative to
raise it. and the cultivation OF the
plant may be considered as thing of
Che past. Such is the wonderful
growth of the discovery. 1t is the
fruit of scientific researches in organic
chemistry, conducted mostly from a
scientific point of view.
One very important coloring matter
related to coal tar. and one of the
original sources of aniline-a product
of as great value as alizarine-has yet
to be produced on a large scale. This
is indigo. Adolph Baeyer. German
chemist. has shown that it can be pro-
duced artiicially, but at present no
practical means of accomplishing it
have been discovered. No doubt how
ever, it will not be long before this 10
achieved, and the cultivation of the
indigo plant will share the fate Of the
madden. Boston Herald.