Production of Direct Dyeing Black Cotton Dyestuff.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Production of Direct Dyeing Black Cotton Dyestuff.
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:-
My foreign correspondents have found that a new black dyestuff of excellent
properties is obtained by heating oxydinitrodiphenylamine with sulphides of
alkalis and sulphur in aqueous solution. The dyestuff thus obtained dyes cotton
direct deep blue black shades, which are fast to rubbing, to light and absolutely
fast to washing and milling. The product from which my correspondents
start is obtained by allowing 1.3 dinitro-4-chlorbenzene to react on para-amido-
phenol in such a manner that only the amido group is substituted. The forma-
tion of oxydinitrodiphenylamine takes place for instance very readily, if the
components are allowed to react upon each other in spirit-solution in molecular
proportion in presence of acetates (:Nietzki Berichte XXVIII, P. 2973:).
Example. 15 parts by weight of oxydinitrodiphenylamine are gradually heated.
to about 140 degrees C. together with 75 parts of crystallised sulphide of sodium
and 30 parts sulphur in presence of a little water. This temperature is main-
tained for several hours, until the mass is almost completely dry. Then it is
heated for a short time to about 160 degrees C. in order to remove the last trace
of water. The dyestuff is thus obtained direct in a soluble form and in a state
ready for technical use.
From its solutions it is precipitated by acids and can thus be isolated and
obtained in a pure state.
Production of Direct Dyeing Black Cotton Dyestuff.
L, 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:-
My foreign correspondents have found that a new black dyestuff of excellent
properties is obtained by heating oxydinitrodiphenylamine with sulphides of

page_text: alkalis and sulphur in aqueous solution. The dyestuff thus obtained dyes cotton
direct deep blue black shades, which are fast to rubbing, to light and absolutely
fast to washing and milling. The product from which my correspondents
start is obtained by allowing 1.3 dinitro-4-chlorbenzene to react on para-amido-
phenol in such a manner that only the amido group is substituted. The forma-
tion of oxydinitrodiphenylamine takes place for instance very readily, if the
components are allowed to react upon each other in spirit-solution in molecular
proportion in presence of acetates (:Nietzki Berichte XXVIII, P. 2973).
Example. 15 parts by weight of oxydinitrodiphenylamine are gradually heated
to about 140 degrees C. together with 75 parts of crystallised sulphide of sodium
and 30 parts sulphur in presence of a little water. This temperature is main-
tained for several hours, until the mass is almost completely dry. Then it is
heated for a short time to about 160 degrees C. in order to remove the last trace
of water. The dyestuff is thus obtained direct in a soluble form and in a state
ready for technical use.
From its solutions it is precipitated by acids and can, thus be isolated and
obtained in a pure state.
Products of the same class which only differ somewhat in their shades from the
above described coloring matter are obtained if instead of the oxydinitrodiphenyl-
amine its homologues are treated in the same way. The dyestuff produced from
oxytolyldinitrophenylamine (; obtained from 1.3-dinitro-4-chlorbenzene and amido-
orthocresol for instance is distinguished by its blue shade.
1
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
claim is-
.
1. The production of coloring matters by heating oxydinitrodiphenylamine or
its homologues with sulphides of alkalis and sulphur substantially as described.
2. The new dyestuffs herein before described.
J.