IMPROVEMENTS IN TREATING MADDER FOR THE PURPOSE OF OBTAINING PURPURINE OR ALIZARINE FROM THE SAME, AND IN APPARATUS TO BE MADE USE OF THEREBY
Year: 1867

page_text: PROVISIONAL SPECIFICATION left by Eduard Leitenberger at the Office
of the Commissioners of Patents, with his Petition, on the 12th October
1867.
I, EDUARD LEITENBERGER, of Cosmanos, in the Empire of Austria, Chemist,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
TREATING MADDER FOR THE PURPOSE OF OBTAINING PURPURINE OR ALIZARINE
FROM THE SAME, AND IN APPARATUS TO BE MADE USE OF THEREBY," to be as
follows:-
These improvements relate to new methods for obtaining the purpurine
and the alizarine separately from madder, and they consist in,-
1ly. Certain new modes of preparing either madder, or what is called
madder charcoal, viz., the results from the treatment of madder by concentrated
sulphuric acid, in such manner that instead of containing both purpurine and
alizarine, the same, after the said preparation, do contain only one of the said
colouring principles.
2ly. In new modes of and apparatus for extracting from madder or from
madder charcoal, prepared accordingly as above said, the colouring principle
left behind in the same or existing in the wash waters.
For preparing madder in such manner as to deprive it either entirely or
nearly so of the purpurine contained therein, the powdered madder is to be
washed repeatedly with water heated to about 122 Fahrenheit, and after
each washing rapidly filtered till the madder is sufficiently deprived of its
purpurine, the latter being soluble in water heated to this temperature; the

page_text: alizarine will remain behind in the madder whilst the purpurine may be
precipitated from the wash waters by means of lime water or caustic barytes,
and afterwards treating with diluted hydrochloric acid and filtering, when
the purpurine will remain on the filter; or the purpurine from the precipitate
might be dissolved therefrom by means of alcohol, this solution be partly
evaporated, the purpurine precipitated by the addition of water separated
by filtration.
My methods of treating madder charcoal are based on the observation made
by ine that according to the length of time powdered madder is submitted to
the action of concentrated sulphuric acid either purpurine or alizarine is
formed; if I wished to obtain purpurine I treat the powdered madder with
about twice its weight of concentrated sulphuric acid, viz., of a specific gravity
of from 0-74 to 0.78, the mass is repeatedly stirred, and after 1 to 2 hours,
according to the nature of the madder, 12 to 14 parts in weight of water are
mixed therewith, and having been left to stand for about 3 hours the mass is
filtered, after which again from 12 to 14 parts of water are added thereto,
and after having been left to stand for 3 to 4 hours the same is filtered again
which addition of water, leaving to stand, and filtration is continued until the
mass has become entirely deprived of acid.
If instead of purpurine alizarine is wished to be obtained from madder
charcoal, the same quantity of concentrated sulphuric acid as above mentioned
is mixed with the powdered madder, but the same is allowed to act thereon
for from 12 to 16 hours instead of from 1 to 2, as is done for obtaining
purpurine, after which 12 to 16 parts in weight of water are mixed with the
carbonized mass, and this latter left to stand for from 5 to 7 hours, after
which the same is filtered, then again 12 to 16 parts of water added, the well-
mixed mass left to stand for from 5 to 7 hours and then filtered again, which
process is repeated until the mass, which will now contain alizarine and
proportionally but very little purpurine, has become entirely deprived of
acid.
For extracting from the madder, or from the madder charcoal prepared in
the manner as above described, the colouring matter left behind therein, I
make use of the apparatus for extracting soluble from insoluble matters, for
which a Provisional Protection was applied for by me on the 11 October
instant, making use thereby of alcohol, benzol, methyles, acetic acid, or other
suitable solvent or extracting menstruum.
The apparatus is shown in longitudinal vertical sectional view in the annexed
Drawing.
The vessel A is filled for about with the madder or madder charcoal,

page_text: prepared as above described, the vessel B is filled for about with the
solvent, by preference alcohol, benzol, methyles, or acetic acid, according
to the purposes for which the purpurine or the alizarine are to be employed;
steam is allowed to enter into the double jacket b until the pressure in B
cause the solvent to pass by the syphon pipe a and rose or strainer a¹ through
the materials in A, after which the steam supply being shut off the vessel B
becomes cooled, and a partial vacuum formed therein, by means of which the
liquid from the vessel A is carried back into the vessel B, which passing of
the solvent from one vessel into the other is to be repeated until a solution
of sufficient strength is obtained in B, which solution is then run off into C,
in which latter water or other precipitating medium is added thereto, and the
entire is pumped up into the reservoir E carried through the air chamber F
into the filtering vessel G and forced up through the filters g, g, the heavier
parts, purpurine or alizarine, remaining in the lower part of the vessel G, from
whence the same may be removed by the valve opening g', whereas the
filtered solution passes into the trough H, and from thence runs into the
still J over the shelves j, steam being allowed to enter into these latter and
heat them sufficiently for causing the alcohol or other more volatile parts to be
distilled off and become condensed in the refrigerator N in order to be used
again in the vessel B, whereas the watery parts are collected by the pipe m
into the trough M, and may be used instead of water for causing the
precipitation or separation in the trough C.