The Manufacture and Production of New Colouring Matters and Leuco Compounds related to the Indigo Series, and of New Materials therefor.
Year: 1893

page_text: Date of Application, 16th Sept., 1893
Complete Specification Left, 6th June, 1894-Accepted, 7th July, 1894
PROVISIONAL SPECIFICATION.
The Manufacture and Production of New Colouring Matters and
Leuco Compounds related to the Indigo Series, and of New
Materials therefor.
I, BENJAMIN WILLCOX of No. 47 Lincoln's Inn Fields in the County of
Middlesex Patent Agent do hereby declare the nature of this invention (which
has been communicated to me from abroad by The Badische Anilin and Soda
Fabrik of Ludwigshafen-on-Rhine in the Empire of Germany) to be as follows:-
This invention relates principally to the manufacture of new-greenish-blue dyes
which are chemically carboxylated indigo compounds. The lenco-compounds of
the said dyes are obtained in the caustic alkali melt from a new initial material
hereinafter named and this new initial material may be produced by the interaction
of amido-phthalic acid [1 2 3] and mono-chloracetic acid.
On oxidizing the leuco-compound a new carboxylated indigo is obtained which
can itself be used as a dye or it can be converted by treatment with sulphuric acid
into sulphonated products which vary in their nature according to the degree of
sulphonation applied.
The following examples will serve to further illustrate the nature of the
invention which is however not limited to the said examples. The parts are by
CARBOXYLATED INDIGO AND ITS LEUCO COMPOUND.
Add about one part of the dry sodium salt of phenyl-glycocoll-dicarboxylic acid
quickly to a melt of about four parts of dry caustic potash at a temperature of
about two hundred and fifty to two hundred and sixty degrees centigrade.
As soon as the mass has acquired a brown colour and the intensity of this colour
no longer increases, the operation is finished. Pour the melt out, and, when cold,
dissolve in about sixty parts of cold water. The solution of the leuco-compound
so obtained at once turns green. Acidify with hydrochloric acid. On standing
the leuco-compound separates out but it is preferable to convert it before such
separation into the colouring matter. For this purpose add ferric chloride to the
solution until a further addition produces no further precipitation of colouring
matter. Collect the dye and purify by re-dissolving in dilute ammonia and
reprecipitating with a mineral acid.

page_text: In the above example alkalies other than caustic potash can also be used in the
melt and to oxidize the leuco-compound other oxidizing agents can be employed
such for example as bichromates in acid solution, or air in the alkaline solution.
In the latter case a stream of air is passed through the solution till the colour
thereof no longer increases in intensity and then the dye is precipitated with
an acid.
The dye can be employed in dyeing from the vat in a manner analogous to that
in which indigo itself is used. Greenish blue shades are for instance obtained on
wool by dyeing from a neutral bath after adding a little zinc dust.
SULPHO ACIDS OF THE CARBOXYLATED INDIGO.
Dissolve about one part of the carboxylated indigo in about ten parts of fuming
sulphuric acid containing about twelve per cent. free anhydride. Cool the mixture
so that the temperature does not rise above about sixty five degrees centigrade and
maintain the mixture at about this temperature for about five hours or until a test
portion is completely soluble in hot water. Pour the product into about one
hundred parts of water, the dye partly separates out; to complete the precipitation
add common salt and filter. Purify by dissolving in sodium acetate and
reprecipitating with a mineral acid. Collect and dry.
The sulpho acid so obtained resembles indigo-carmine in its properties but dyes
wool from the acid bath giving shades much greener than are given by indigo-
carmine.
Sulpho acid yielding still greener shades can be obtained by sulphonating more
energetically by using sulphuric acid containing a higher percentage of free
anhydride.
Dated this 16th day of September 1892
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, Agents.
COMPLETE SPECIFICATION.
The Manufacture and Production of New Colouring Matters and
Leuco Compounds related to the Indigo Series, and of New
Materials therefor.
I, BENJAMIN WILLCOX, of 47 Lincoln's Inn Fields in the County of Middlesex,
Patent Agent, do hereby declare the nature of this invention (which has been
communicated to me from abroad by The Badische Anilin and Soda Fabrik of
Ludwigshafen-on-Rhine 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:―
This invention relates principally to the manufacture of new greenish-blue dyes
which are chemically carboxylated indigo compounds. The leuco compounds of
the said dyes are obtained in the caustic alkali melt from a new initial material
hereinafter named phenyl-glycocoll-di-carboxylic acid and this new initial material
may be produced by the interaction of amido-phthalic acid (1:2:3) and mono-
chlor-acetic acid.
On oxidizing the leuco-compound a new carboxylated indigo is obtained which
can itself be used as a dye or it can be converted by treatment with sulphuric acid
into sulphonated products which vary in their nature according to the degree of
sulphonation applied.

page_text: The sulpho acid so obtained resembles indigo-carmine in its properties but dyes
wool from the acid bath giving shades much greener than are given by indigo-
carmine.
Sulpho acid yielding still greener shades can be obtained by sulphonating more
energetically by using sulphuric acid containing a higher percentage of free
anhydride.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The manufacture of a new indigo-carboxylic acid by first treating amido-
phthalic acid with mono-chlor-acetic acid so as to obtain phenyl-glycocoll-di-
carboxylic acid, then treating this new material in the caustic alkaline melt and
finally oxidizing the leuco-compound so obtained all substantially in the manner
herein before described.
2. The manufacture of sulpho acids of indigo-carboxylic acid by first preparing
the indigo-carboxylic acid in the manner berein described and claimed in the
foregoing claiming clause and then sulphonating it by treatment with sulphuric
acid.
3. The manufacture of a leuco-compound of carboxylated indigo by first
preparing phenyl-glycocoll-di-carboxylic acid and then treating this in the caustic
alkaline melt.
4. The manufacture of phenyl-glycocoll-di-carboxylic acid by treating amido-
phthalic acid with mono-chlor-acetic acid substantially as described.
5. The manufacture of phenyl-glycocoll-di-carboxylic acid carboxylated iudigo
and its leuco-compound and sulpho acids in the manners herein described in the
respective examples.
6. As new articles of manufacture the phenyl-glycocoll-di-carboxylic acid, the
carboxylated indigo, its leuco compound, and sulpho acids, all such as can be.
obtained substantially as hereinbefore described.
Dated this 6th day of June 1894.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.