Producing Dyestuffs from Amidophenols.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Producing Dyestuffs from Amidophenols.
I, SYDNEY PITT, of Sutton, in the County of Surrey, Gentleman, do hereby
declare the nature of this invention (which has been communicated to me from
abroad by Leopold Cassella & Co., of Frankfort-on-Main, in the Empire of Germany,)
to be as follows:
If chloride of sulphur is allowed to react upon amidophenols, new and valuable
dyestuffs result. They possess a strong phenol character, dissolve in caustic
alkalis, and such solutions dye vegetable fibres intense shades. The dyestuffs are
entirely different from the bodies which have been obtained by the action of
sulphur in presence of alkalis or ammonia upon amido-phenols. They possess,
contrary to the latter, basic properties and dissolve in strong acids. They are
also much more intense, and dyeings produced therewith do not rub off. Contrary
to the known coloring matters, they may be transformed into sulphonic acids.
By chloride of sulphur is understood the combination S, Cl, and the products
containing a larger proportion of chlorine, such as S Cl₂ etc. As amidophenols the
three amidophenols, their homologues, alkyl-, and alphyl-derivatives may be
used.
The reaction takes place in two phases which can be strictly distinguished if
the process is carried out in presence of a dissolving agent, as for instance
tetrachloride of carbon.
At first a colorless intermediate body is formed. The same can only be trans-
formed into a dyestuff by heating it to a high temperature, and differs in this
respect materially from the leuco compound of the dyestuff derived from the latter
by reduction with zinc dust in alkaline solution which is transformed into the
original dyestuff by the action of the oxygen of the air.
EXAMPLE.
50 parts by weight of para amidophenol are slowly heated to about
70 degrees C. together with 150 parts by weight of chloride of sulphur in a
vessel provided with a cooler turned upward; this temperature is maintained for
about five hours, and then gradually raised to 190 to 200 degrees C. whereby the
formation of the dyestuff takes place. The product of the reaction forms a black
mass. In order to remove any amidophenol-chlorhydrate which may have re-
mained unchanged, the mass is powdered and boiled with water in which the
free dyestuff-acid is not soluble. In order to obtain the dyestuff in a soluble
form, it is transformed with soda lye into its sodium salt, the solution of which
is then evaporated.
The product thus obtained dissolves in water with a blue black shade, and
produces direct on unmordanted cotton, especially in a bath charged with common
salt a blue black.

page_text: In analogous manner brownish black dyestuffs are obtained from ortho and
meta amidophenol, black dyestuffs from para amido-ortho-cresol, brownish violet
dyestuffs from para oxydiphenylamine, all possessing the same dyeing properties
as the derivative of para amidophenol above described.
Dated this 27th dox of Ontahan 1007'
Producing Dyestuffs from Amidophenols.
I, SYDNEY PITT, of Sutton, in the County of Surrey, Gentleman, do hereby
declare the nature of this invention (which has been communicated to me from
abroad by Leopold Cassella & Co., of Frankfort-on-Main, in the Empire of Germany,)
and in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement:-
1
If chloride of sulphur is allowed to react upon amidophenols, new and valuable
dyestuffs result. They possess a strong phenol character, dissolve in caustic
alkalis, and such solutions dye vegetable fibres intense shades. The dyestuffs are
entirely different from the bodies which have been obtained by the action of
sulphur in presence of alkalis or ammonia upon amido-phenols. They possess,
contrary to the latter, basic properties and dissolve in strong acids. They are
also much more intense, and dyeings produced therewith do not rub off. Contrary
to the known coloring matters, they may be transformed into sulphonic acids.
By chloride of sulphur is understood the combination S, Cl, and the products
containing a larger proportion of chlorine, such as S Cl, etc. As amidophenols the
three amidophenols, their homologues, alkyl-, and alphyl-derivatives may he
used.
The reaction takes place in two phases which can be strictly distinguished if
the process is carried out in presence of a dissolving agent, as for instance
tetrachloride of carbon.
At first a colorless intermediate body is formed. The same can only be trans-
formed into a dyestuff by heating it to a high temperature, and differs in this
respect materially from the leuco compound of the dyestuff derived from the latter
by reduction with zinc dust in alkaline solution which is transformed into the
original dyestuff by the action of the oxygen of the air.
EXAMPLE.
50 parts by weight of para amidophenol are slowly heated to about
70 degrees C. together with 150 parts by weight of chloride of sulphur in a
vessel provided with a cooler turned upward; this temperature is maintained for
about five hours, and then gradually raised to 190 to 200 degrees C. whereby the
formation of the dyestuff takes place. The product of the reaction forms a black
mass. In order to remove any amidophenol-chlorhydrate which may have re-
mained unchanged, the mass is powdered and boiled with water in which the
free dyestuff-acid is not soluble. In order to obtain the dyestuff in a soluble
form, it is transformed with soda lye into its sodium salt, the solution of which
is then evaporated.
The product thus obtained dissolves in water with a blue black shade, and
produces direct on unmordanted cotton, especially in a bath charged with common
salt a blue black.
In analogous manner brownish black dyestuffs are obtained from ortho and
meta amidophenol, black dyestuffs from para amido-ortho-cresol, brownish violet
dyestuffs from para oxydiphenylamine, all possessing the same dyeing properties
as the derivative of para amidophenol above described.

page_text: Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1. The production of coloring matters by the action of chloride of sulphur on
the amidophenols and their derivatives substantially as described.
2. The new coloring matters hereinbefore described.