Year: 1886

page_text: I, OLIVER IMRAY of N° 28 Southampton Buildings, Chancery Lane, in the
County of Middlesex, Fellow of the Institute of Patent Agents, do hereby declare
the nature of this invention and in what manner the same is to be performed
to be particularly described and ascertained in and by the following statement:―
This invention relates to the manufacture of a Resorcine Blue by transforming
Resorcine, having the formula, C, H*, (0², H²), into a substance which may be
termed Resorcine Blue having an assumed empyric formula C¹³, H¹³, N², O® and
adapted for use principally as a dye.
For this purpose, there is added to Resorcine, an aqueous solution of ammonium
hydrate in excess, to effect a solution.
To this ammonia-Resorcine solution is added by preference a solution of ammonia-
carbonate of copper, about equal in weight to the Resorcine employed; a greater
quantity is superfluous, with a smaller quantity the process is retarded.
Into the mingled solutions of ammonia resorcine and ammonia-carbonate of
copper is now dipped a copper plate, which may be in the form of a slowly
revolving disc partly submerged in the liquid. Instead of such a revolving disc a
copper plate, or plates, may be repeatedly dipped into the solution. The addition
of the ammonia carbonate of copper may be dispensed with when copper discs or
plates are employed, but its presence accelerates the reactions.
During the operation above described, ammonia water is added, from time to
time, to keep the solution alkaline and replace loss by evaporation.
The chemical changes take place at ordinary temperatures and consist in
molecular transpositions among the resorcine groups, the primary formation of
cuprous ammonia, the secondary combination of the cuprous ammonia and resorcine
the elimination of water and production of amidogen, two molecules of which
combine with the resorcine residues, in place of displaced hydrogen.
The movement of the metallic copper from the solution through the air and back
again, forms cuprous ammonia, making a solution that acts at once upon the
resorcine like a battery, producing the chemical combination of two amidogen
groups in the resorcine molecule residues.

page_text: In order to ascertain when the transformations are completed, a sample 18
evaporated to dryness at a temperature not exceeding 212° Fahr, and the dry
residue is digested with lukewarm water which dissolves out any untransformed
resorcine, forming a solution which may be mixed with a small quantity of ether,
or alcohol, to which a little sodium nitrite is added, and followed with enough
hydrochloric acid to liberate the nitrous acid from the sodium nitrite. This
operation and the attendant reaction produces a yellow tri-nitro-resorcine, if the
mixed aqueous and etherial, or alcoholic solution, contains free, untransformed
resorcine.
Instead of the above test, the aqueous solution mentioned, may have added to it
a dilute solution of ferric-chloride, which strikes a dark violet color, if free
resorcine is present.
By either, or both of these tests it may be readily ascertained whether the
treatment has been carried to such a point that no free or untransformed resorcine
remains in the solution. When this is ascertained, the entire solution is treated as
follows:-
The solution is, first neutralized by the addition of a dilute acid, preferably
sulphuric or bydro-chloric acid, (which must be added in excess) and is then
boiled.
The coloring matter precipitates on cooling and may be filtered out, or the
super-natant fluid may be decanted and the colour collected and dried.
This completes the manufacture of the coloring matter for ordinary commercial
purposes.
The isolation of the coloring matter after the transformations are completed, may
be more thoroughly obtained by immersing a sheet of metallic zinc in the solution
until all the copper is precipitated in the metallic condition.
When this is done, it is proper, after the precipitation of the copper, to filter the
solution, which contains the color with ammonia-zinc-oxide and ammonia-zinc-
carbonate, and then to add dilute sulphuric or hydro-chloric acid in excess, and
subsequently to boil.
After cooling, the coloring matter precipitates and may be collected by filtration
or decantation. The color is then dried, whereupon it is ready for use as a dye.
If a very high degree of purity is required, the coloring matter formed as above
described may be again dissolved in dilute ammonia water and the solution again
be made acid and boiled, when the coloring matter will again precipitate in a purer
condition, this step being essentially a repetition of the final step described above.
The test mentioned for determining whether the chemical transformations are
complete is a convenient method for ascertaining that fact, but there are other
ways of arriving at the same information. For example, a portion of the solution
may be neutralized with acid and boiled, and the resulting precipitate being
filtered these may be added to it while on the filter a cold solution of carbonate of
ammonia. If the solution passes through the filter and exhibits a green fluor-
escence, while viewed in a body, as in a test tube, the operation should be
continued. If, on the other hand, it imparts to the ammonium-carbonate a blue-
black color, the transformations may be regarded as complete.
The whole of the solution may be treated in the same manner as the sample just
described. It should be noted, however, that when the ammonium-carbonate
solution comes through the filter nearly colorless, its use should be discontinued and
followed by pure water until the water which comes through is of an indigo-blue
color, when its use is discontinued and the coloring-matter remaining on the filter
is dried at a steam heat.
The coloring matter formed by the process above described is almost wholly
insoluble in water or in dilute acids. With concentrated sulphuric acid in the cold
it dissolves, forming a green solution which becomes blue by dilution and finally
precipitates, but heating such solution decomposes the color; with concentrated
muriatic acid it yields a purple solution, which becomes successively green and blue,
according to the extent of dilution, resulting finally in precipitation

page_text: These qualities manifest themselves when the process is conducted substantially
as above described, but there is a disposition of the materials to form modified and
substitution products according to the degrees of saturation in solution, and the
reagents and temperatures employed, so that the tests mentioned may seem to be
unreliable.
For instance, after the formation of the color as described, and the precipitation
of the copper by zinc, the solution will be found to contain color, Ammonia-Zinc-
Oxide, and Ammonia-Zinc-Carbonate.
If this solution, is boiled with considerable excess of dilute sulphuric acid for a
long time, the color forms a combination soluble in pure water.
Or, if the said solution is boiled with a mixture of sulphuric, or hydrochloric
acid, and ethyl, or Methyl-alcohol, Ethyl, or Methyl substitution products, are
formed which are also blue dyes, but are possessed of qualities different from those
of the original color.
Many substitutions like the above can be made, particularly in the presence of
the Zinc salts, the Ethyl and Methyl substitutions yielding new substances having
great affinity for cotton.
With bases, the Resorcine blue combines to form Lakes and is soluble in alkalies
giving blue solutions. It is of great value as a dye, taking the place of indigo
and giving results which are equal, commercially, to those produced by the best
qualities of indigo.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that
what I claim is :-
1. The manufacture of a "Resorcine Blue" by dissolving resorcine in an excess
of ammonia water, agitating the solution with or without the addition of ammonia
carbonate of copper by repeated immersions of a copper plate, adding dilute acid
in excess, boiling and filtering, substantially as described.
2. The use, as a dye, of "Resorcine blue" manufactured substantially as herein
described, and distinguished by the qualities herein set forth.