IMPROVEMENTS IN THE MANU- FACTURE OF COLOURING MATTERS
Year: 1883

page_text: LETTERS PATENT to Paul Joachim Meyer Doctor of Philosophy, of Berlin,
Prussia, German Empire for an Invention of IMPROVEMENTS IN THE MANU-
FACTURE OF COLOURING MATTERS
PROVISIONAL SPECIFICATION left by the said Paul Joachim Meyer at the
Office of the Commissioners of Patents on the 9th April 1883.
PAUL JOACHIM MEYER Doctor of Philosophy, of Berlin Prussia, German Empire,
"IMPROVEMENTS IN THE MANUFACTURE OF COLOURING MATTERS
29
I expose Aniline, Toluidine, Hylidine, Cumidine, Naphtylamine, or their alkylised
or halogenised products of substitution (Chloride Bromide, Iodide, Methyl or
Aethyl derivatives) or their corresponding Diamines (Phenylendiamine, Toluylen-
diamine) to the action of dichloracetic dibromacetic or dinio dacetic acid or of the
Amides thereof. This can be done either by continued boiling of the solutions
thereof or, preferably, by melting a mixture over an open fire; under certain
circumstances especially with liquid bases, or such as will melt at low temperatures,
the temperature of a water bath will suffice.
The proportions are preferably so chosen that 4. mol. of the base are employed
for 1 of the acid. Deviations from these proportions do not prevent the reaction
from taking place.
The products of the direct action are Imesatine products of substitution which
when treated with strong acids or bases readily (some even at the ordinary
temperature) exchange the Imido groups for Oxygen and yield Isatine or Isatine
products of substitution; the reactions take place according to the following
equations;

page_text: The operation is carried out as follows: 1 part by weight of dichloracetic acid is
heated for instance with 3.3 parts by weight of Paratoluidine in open vessels at
100° until the mixture which at first becomes clear and very liquid, has become
viscous or stiff.
The product, Imesatine, freed from chloric salts by lixiviation is then treated
preferably with hydrochloric acid at the ordinary temperature or slightly heated
and according to the above equations paratoluidine and an Imsatine product of
substitution (Methylisatine) is produced by reason of the addition of water.
Instead of the Dichloracetic acid (or dibromacetic or dimoid acetic acid) or of
the Amidines thereof, the aldehydes thereof or the Dichloracetic Dibromacetic or
Diniodacetic acetones may be employed.
The Isatine or the Isatine products of substitution may be transformed into
Indigo or Indigo products of substitution in the usual manner by transformation
into chloride and reduction of the same say by Zinc or Iodide of Hydrogen into
glacial acetic acid.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Paul Joachim Meyer in the Great Seal Patent Office on the
9th October 1883.
Paul Joachim MEYER Doctor of Philosophy, of Berlin, Prussia German Empire
"IMPROVEMENTS IN THE MANUFACTURE OF COLOURING MATTERS
"
Paratoluidine is exposed to the effects of dihalogenised acetic acid (dichloric,
dibromic or di-iodic acetic acid) this can be effected either by directly fusing them
together, even at the temperature of a waterbath, or by digesting their solutions
in open or in closed vessels.
The proportions of quantity are preferably chosen so, that for 1 molecule of acid
4 molecules of the base are used, therefore for instance 1 part by weight of
dichloracetic acid for 332 parts by weight of paratoluidine (1 part by weight
of dibromacetic acid for 1.96 parts by weight of partoluidine, 1 part by weight of
di-iodacetic acid for 1-37 parts by weight of paratoluidine); deviation from these
proportions does not prevent the taking place of the reaction, but will diminish
the yield.
The termination of the reaction is characterised by the presence of ample
quantities of hydrochloric acid which forms with the base bydrochlorate of
paratoluidine; if the substances are directly fused together, the mixture which
first has become clear and very liquid, ultimately becomes viscuous or stiff.
The product of the interaction is, preferably after previous elimination of the
hydrochlorate of toluidine by lixiviation with water, advantageously dissolved in
alcohol and caused to crystallize. The crystals, or crystal-crusts, which separate
consist of paratoluylised paramethylimesatin, that is to say of paramethylisatin in
which the place of one atom of oxygen thereof is taken by the rest of paratoluidine.
The chemical process which takes place may be expressed as follows:
C, H, Cl₂ O, + 4 NH₂ (C₂ H₁₂) = C₁ H₁ N, O + 2 NH, (C, H₂) HCl + H, O + H„
Dichloracetic acid Paratoluidine Paratolulised Para-
Hydrochlorate of Paratoluidine
methylimesatin
The paratoluylised paramethylimesatin thus obtained being treated with strong
acids (with hydrochloric acid even at the ordinary temperature) or with bases,
paratoluidine is separated, water being at the same time taken up and
paramethylisatin is produced according to the following equation:
C16 H₁4 N, O
Paratoluylised paramethylimesatin
+ E, O = C, H, N, O + NH₂ (C, H₂).
Paramethylisatin
Paratoluidino
C, HCl, O, . Cụ H. + 4NH, (C, E) = C
Dichloracetic ether
14
E, N,O + 2NH, (C, E) HO
+ C₁₂ H¿ (OH) + H₂
Alcohol
C, HCI, O. NH, +3 NH, (C,H)=C₁₁ N₂O+Nн₂ (C, H,) HCI+NH₂HƠl+H
Dinklestin Amida
Ammonium Chlorid

page_text: The paramethylisatin possesses properties similar to those of the ordinary isatin
and can be transformed into paramethylindigo according to the known method by
transformation into the chloride and subsequent reduction, which paramethylindigo
in its general properties resembles the natural indigo and may be used in its
place.
Aniline, Metoluidine Xylidine, Cumidine Naphtylamine, their alkylised or
halogenised products of substitution (chloric, bromic, iodic methyllic and ethyllic
derivatives) and the corresponding Diamines (Phenylendiamine Toluylendiamine)
act similarly to paratoluidine; by the effects of the dihalogenised acetic acids and
of their derivatives they are transformed first into products of substitution of
imesatins (phenylised imesatin, metatoluylised Metamethylimesatin &c) then, by
the effects of strong acids or bases, into isatin, metamethylisatin &c from which
by chlorination and reduction artificial indigo, Metamethylindigo &c, can be
produced.
The final products thus obtained, in their properties resemble, generally speaking,
the above described paramethylindigo.
As the transformation of ordinary isatin into indigo by the above indicated
reactions is already known, I do not claim the same, but only the employment of
the reaction for the transformation of the indicated products of substitution of
isatin into products of substitution of Indigo.
Nor do I claim the employment of dihalogenized Aceton (mentioned in the
provisional specification).
Having thus described the nature of my said invention and the manner of
performing the same, I wish it to be understood that what I claim is
First: The production of Isatin or of products of substitution of Isatin from
dihalogenised acetic acids or from their Amides, Ethers, and Aldehydes on the one
hand and the above indicated Amines on the other, by directly fusing them
together or by boiling their solutions and treating the product of the interaction
with strong acids or bases.
Second: The transformation of the thus obtained products of substitution of
Isatin (Methylisatin, Dimethylisatin, Trimethylisatin, their halogenised and
alkylised products of substitution and Amido and Methylamido Isatin) into a
product of substitution of Indigo by reducing the Chlorides thereof.
In witness whereof I, the said Paul Joachim Meyer, have hereunto set my
hand and seal this twentyninth day of September in the year of our Lord One
thousand eight hundred and eighty three
PAUL JOACHIM MEYER (L.S.)