The Production of Azo Dye-stuff's Derived from a1 a Azimido- naphtalene.
Year: 1893

page_text: Date of Application, 22nd Dec., 1893
Complete Specification Left, 21st Sept., 1894-Accepted, 27th Oct., 1894
PROVISIONAL SPECIFICATION.
The Production of Azo Dye-stuff's Derived from a₁ a Azimido-
naphtalene.
I, SYDNEY PITT, of Sutton, in the County of Surrey, Gentleman, (a com-
munication to me from abroad by Leopold Cassella & Co., of No. 19 Liebigstrasse,
Frankfort on Main, in the Empire of Germany,) do hereby declare the nature of
this invention to be as follows:-
In the German Patent No. 63507 it has been shown that a₁ a naphtylene-
diamine-disulpho acid may be combined with diazo bodies. As described in the
German Patent No. 70031 the thus obtained azo dye-stuffs are transformed into
the corresponding azo derivatives of the a₁ a amidonaphtol-disulpho acid by
treating them with mineral acids or caustic alkalies. If however nitrous acid is
used in order to obtain an analogous reaction, it will be observed that one molecule
of nitrous acid is absorbed by one molecule of the dye-stuff and that a new dye-
stuff is produced. Examination has shown that this reaction leads to the
formation of bodies which contain the characteristic group of
and which therefore are to be designated as azimido dye-stuffs. This reaction
shows itself with all azo derivatives of the mono- and di-sulpho acids of the
a a naphtylene-diamine examined up to the present. In their general behaviour
the dye-stuffs show a certain similarity to the corresponding azo derivatives of
the a, a, dioxynaphtalenesulpho acids. Their shades are very pure and somewhat
bluer than those of the dioxy dye-stuffs. They are comparatively very easily
soluble and give unusually level shades. Remarkable is their great fastness to
light.
The process may be carried out as illustrated by the following example :
27.6 kilos. p. nitraniline are diazotised and combined in the manner previously
described, in acid solution with 75 kilos. as a naphtylenediamine B, ẞ, disulpho
acid. When the dye-stuff has formed a solution of 23 kilos. nitrite of sodium is
added. The dye-stuff which has separated as a dark colored precipitate is at first
dissolved by the action of the nitrous acid. In a short time small yellowish red
needles of the azimido dye-stuff begin to separate. After a few hours the
same is filtered off. It dyes wool in an acid bath a magenta red shade. Dye-stuffs
of similar dyeing properties are obtained, if in the place of p. nitraniline the
isomeric nitraniline or nitrotoluidine, amidoazobenzole, amidoazotoluole, nitro-
naphtylamine are used. The shades vary between bluish red and reddish violet.
If in the place of the naphtylene-diaminedisulpho acid u̟ o̟ naphtylene-diamine-
monosulpho acid for instance the acid of the British Patent 46133 is used, dye-
stuffs of quite analogous properties are obtained which only dissolve somewhat
more difficultly..
Dated this 22nd day of December 1893.

page_text: COMPLETE SPECIFICATION.
The Production of Azo Dye-stuffs Derived from a₁ a Azimido-
naphtalene.
I, SYDNEY PITT, of Sutton, in the County of Surrey, Gentleman, (a com-
munication to me from abroad by Leopold Cassella & Co., of No. 19 Liebigstrasse,
Frankfort on Main, in the Empire of Germany,) 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 :-
In the German Patent No. 63507 it has been shown that as a naphtylene-
diaminedisulpho acid may be combined with diazo bodies. As described in the
German Patent No. 70031 the thus obtained azo dyestuffs are transformed into
the corresponding azo derivatives of the a₁ a amidonaphtoldisulpho acid by
treating them with mineral acids or caustic alkalies. If however nitrous acid is
used in order to obtain an analogous reaction, it will be observed that one molecule
of nitrous acid is absorbed by one molecule of the dye-stuff and that a new dye-stuff
is produced. Examination has shown that this reaction leads to the formation of
bodies which contain the characteristic group of
and which therefore are to be designated as azimido-dye-stuffs. This reaction
shows itself with all azo derivatives of the mono- and di-sulpho acids of the
a a naphtylene-diamine examined up to the present. In their general behaviour
the dye-stuffs show a certain similarity to the corresponding azo- derivatives of
the as a dioxynaphtalenesulpho acids. Their shades are very pure and somewhat
bluer than those of the dioxy dye-stuffs. They are comparatively very easily
soluble and give unusually level shades. Remarkable is their great fastness to.
light.
The process may be carried out as illustrated by the following example:
27.6 kilos. p. nitraniline are diazotised and combined in the manner previously
described, in acid solution with 75 kilos. a, a naphtylene-diamine ẞ, ẞ, disulpho
acid. When the dye-stuff has formed a solution of 23 kilos. nitrite of sodium is
added. The dye-stuff which has separated as a dark colored precipitate is at first
dissolved by the action of the nitrous acid. In a short time small yellowish red
needles of the azimido dye-stuff begin to separate. After a few hours the same is
filtered off. It dyes wool in an acid bath a magenta red shade. Dye-stuffs of
similar dyeing properties are obtained, if in the place of p. nitraniline the isomeric
nitraniline or nitrotoluidine, aniidoazobenzol, amidoazotoluol, nitronaphtylamine are
used. The shades vary between bluish red and reddish violet.
If in the place of the naphtylene-diaminedisulpho acid a a naphtylene-
diaminemonosulpho acid for instance the acid of the British Patent 4613³ is used,
dye-stuffs of quite analogous properties are obtained which only dissolve somewhat
more difficultly.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. Producing azo dyestuffs derived from a, a, azimidonaphtalene by treating the
azo derivatives of a, a, naphtylenediaminesulpho acids with nitrous acid, substan-
tially as described.
2. The new dyestuffs herein before described deriving from azimidonaphtalene.
Dated this 30th dex of Aug 1804
SYDNEY PITT.