The Stark County Democrat. [volume] (Canton, Ohio) 1833-1912, 1906-10-05
COAL TAR

Drugs are Derived.
We are just beginning to learn
what a wonderful fortune we have
fallen heir to. Recently a body of
scientists assembled in honor of Will
liam Henry Perkin, who, by his dis
covery of mauve just fifty years ago,
inaugurated the dyeing industry,
which was the first of the great in
dustries developed from coal tar, says
the New York Herald
Long before Perkin made his fam
Gus discovery four different chemists,
working independently at different
times in widely separated places with
entirely different materials and en-
tirely different processes, produced
colorless aromatic oil which had the
property of producing beautiful crys-
talline salts. Each chemist thought his
discovery an original one and gave it
an original name. The first man who
produced the substance by distilling
the well known dye indigo called it
crystalline; the next man to obtain
the substance from coal tar called it
kyanol; the third chemist who also
worked with indigo, named his dis
covery aniline, and the fourth man,
who derived the salts from benzine,
called the derivative benzidam. But
all these were different names for the
very same thing, as was shown by
the chemist Hoffman, and this oil we
now call aniline.
In the manufacture of Illuminating
gas from coal about 140 pounds of tar
are obtained from every ton of coal.
In the early history of gas making,
before the value of this tar was
known, manufactures were only too
anxious to get rid of the stuff. 1t
possessed no market value and was
literally given away to any one who
was willing to pay the carriage. Its
only use was for coating fence posts,
tiles, etc, to protect them from the
weather. Some attempts were made
to convert the tar into a patent fuel
by compressing it into briquettes. But
very little of it was used in this way,
| and the manufacturers could rid their
works of the stuff only by burning it.
| Thirty-fve years before the discovery
of mauve coal tar was distilled and
! several oils discovered One of these
! oils, namely benZine, was used by a
! Scotchman named Mcintosh to dis
| solve rubber, which he used in the
manufacture of rain coats which still
| bear his name. But a very limited
| quantity was used in this way, and
It was not until Perkins showed it's
| commercial possibilities in the manu-
faCture of dyes that the stuff rose to a
respectable valuation.
Take the production of mauve. for
example. To start with, coal tar is
distilled to produce benzene (that. by
the way, must not be confused with
benzene, which is produced from petro-
! leum). This must then be nitrated to
form nitro-benzene. Nitro benzene is
| now mixed with acetic acid and iron
filings and distilled at a high tenn
| perature to produce aniline, with
which Perkin began. First he pro-
duced a sulphate of aniline, then he
mixed this with potassic dichromate
and let the mixture settle. In a few
hours a muddy black precipitate was
formed in the bottom of the recepta-
Gle. This black substance was now
washed to rid it of potassium sulphate
! and than tTpotAh Nrrith
which the residue was dissolved in
alcohol to produce the dye mauve.
Similar processes, some of them far
more complicated, must be gone
through to produce other dyes.
To be sure there are many sub
stances which can be obtained direct
from coal tar without mixing in other
| chemicals, and number of these sub
stances are used in the new state
They are procured by heating the tar
slowly, and thus distilling the various
constituents. First there is light,
waterly liquor, next comes a light oil,
then, as the temperature grows
higher, carbOlic oil is obtained, fol-
lowed by creosote oil and finally an
thracene oil, leaving a residue of pitch
in the still. Aside from caTbolic, there
are more than one hundred different
drugs derived from coal tar-antipy-
I rine, for instance, and phenacetine,
and thallium, the great yellow fever
medicine.
One of the most remarkable derivi-
tives of coal tar is saccharine, sub,
stitute for sugar, which is largely
used in jams, jellies, etc., because it
does not ferment. Saccharine is more
than three hundred times sweeter than
cane sugar, yet it contains no nutri-
! ment. 1t is very useful for favoring
the food of diabetic patients who are
unable to use sugar. In addition to
its other properties saecharine is a