Improvements in the Manufacture of Colouring Matters.
Year: 1889

page_text: Date of Application, 21st Aug., 1889
Complete Specification Left, 16th May, 1890-Accepted, 16th Aug., 1890
PROVISIONAL SPECIFICATION.
[Communicated from abroad by Messrs. WIRTH & Co., of Frankfort-on-the-Main,
in the Empire of Germany, acting as agents of A. Leonhardt & Co., of Muhlhain,
near Frankfort-on-the-Main, in the Empire of Germany, Manufacturers.]
Improvements in the Manufacture of Colouring Matters.
I, HENRY HARRIS LAKE of the firm of Haseltine, Lake & Co., Patent Agents,
Southampton Buildings, in the County of Middlesex, do hereby declare the nature
of this invention to be as follows:-
This invention relates to the manufacture of red colouring matters from aldehydes
and amidophenols or amidonaphthols.
For instance if formaldehyde and dimethylamidophenol are brought to react upon
each other a colourless product of condensation a derivative of diphenylmethane is
formed. This condensation will take place in an aqueous alcoholic solution with or
without the presence of acids.
With benzaldehyde there is also a product of condensation formed which is most
probably a derivative of triphenylmethane.
The intermediary products thus obtained are transformed into leucocompounds of
a new colouring matter by treatment with dehydrogennizing agents for instance,
sulphuric acid, chloride of zinc. At this reaction a partial formation of colouring
matter takes place by voluntary oxydation.
The completion of the formation of the colouring matter is effected by digestion
of an acidous aqueous solution of the leucocompound with an oxydizing agent.
The colouring matters thus obtained dissolve in water with a strong fluorescence
they are capable of dyeing wool, silk and mordanted cotton and excel by their purity
of shade and fastness.
These colouring matters can also be obtained in a direct way if in place of the
aldehydes the corresponding acids or acidchlorides are brought into reaction with
amidophenols or amidonaphthols preferably in presence of a condensing agent for
instance chloride of zinc, sulphuric acid. This way for instance a red fluorescing
dyestuff is formed direct if dimethylamidophenol is heated in prescence of chloride of
zinc with benzotrichloride (instead of benzaldehyde.
Dated this 21st day of August 1889.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Colouring Matters.
I, HENRY HARRIS LAKE of the firm of Haseltine, Lake & Co., Patent Agents,
Southampton Buildings in the County of Middlesex, do hereby declare the nature of
this invention and in what manner the same is to be perforined, to be particularly
described and ascertained in and by the following statement :-
If formaldehyde is allowed to react upon dimethyl- or diethyl-metaamidophenol at
the ordinary temperature, there are formed colourless products of condensation,
namely tetramethyl- or tetraethyl diamido dioxi diphenylmethan.

page_text: At this stage the formation of colour can to a small extent generally be observed,
the colour however becomes the principal product of reaction if the above named oxides
are subsequently subjected to an oxidation.
In this manner beautiful pink dye-stuffs are obtained, the watery and alcoholic
solutions of which show a magnificent fluorescence and which are excellently adapted
for dyeing or printing on cotton.
By this property they distinguish themselves favorably from the dyestuffs of similar
shade, the so-called rhodamines, which especially for tinting the cotton fibre are of
less value.
The manner in which this invention is to be carried out is as follows:-
FIRST STAGE. MANUFACTURE OF TETRAALKYLDIAMIDO-DIOXIDIPHENYLMETHAN.
Example 1. A solution of 28 kilos. of dimethylmeta-amidophenol in 200 litres
alcohol of about 60% is digested with 10 kilos. of an aqueous solution of formaldehyde
of 30%. After standing for some length of time at the ordinary temperature, the
product of condensation formed separates itself from the mother lye. It forms small
shiny leaves of the melting point 180° C. and possesses basic as well as acid properties.
From its solution in hydrochloric acid it may be precipitated by means of soda,
while from its solution in caustic soda lye it will be precipitated by means of
acetic acid.
Example 2. 14 kilos. of dimethylmeta-amidophenol are dissolved in 60 litres of
water and 11 kilos. of concentrated muriatic acid and the solution is digested cold
with 3.8 kilos. of a solution of formaldehyde of 40%. If after a prolonged standing,
the smell of aldehyde has disappeared, the solution is diluted to a volume of about
200 litres then heated to 60° Cent., and a gradual precipitation by means of soda is
effected, whereby first some impurities are precipitated and then from the filtrate the
tetramethyldiamido-dioxidiphenylmethan formed by the condensation, which can be
purified by crystallisation from diluted alcohol.
Example 3. 16 kilos. of diethylmeta-amidophenol are dissolved in 12 kilos. of
cautic lye of 33% and 80 litres of water and the cold solution is digested with
3.8 kilos. of a solution of formaldehyde of 40%. If after a prolonged standing, the

page_text: smell of aldehyde has disappeared, the solution is diluted up to a volume of 200 litres
heated to 50° Cent. Precipitation is then effected, by diluted acetic acid, first of some
impurities and then from the filtrate of the tetraethyldiamido-dioxidiphenylmethan
formed, which can be easily obtained in quite a pure state by crystallization in diluted
alcohol. The melting point is at 164° Cent. and in its chemical properties it is very
similar to the above described tetramethyl derivative.
SECOND STAGE. MANUFACTURE OF TETRAALKYLDIAMIDO-DIPHENYLMETHANOXIDE.
10 kilos. of one of the products of condensation obtained in the first stage are heated
to about 100° Cent. with 50 kilos. of ordinary concentrated sulphuric acid, the mass
is thereby dissolved and assumes a yellow colour. The termination of the reaction
can be tested by pouring a sample into water where it must dissolve with a light pink
colour and a yellowish fluorescence, and after oversaturating with caustic soda lye and
filtering, the filtrate on the addition of acetic acid must not show any or only an
insignificant precipitation.
The oxides thus obtained can be isolated by pouring the whole mass into cooled
water and precipitating with caustic soda lye.
They do not possess any acid properties but are entirely of a basic nature.
Amongst the dehydrating agents which we employ we have found sulphuric
acid to be the best, but chloride of zinc and a little muriatic acid would also do."
THIRD STAGE. PRODUCTION OF THE DYE-Stuffs.
For the oxidation of the oxides described under second stage most of the usual
oxidizing agents can be employed. We mention as an example nitrous acid, peroxyde
of lead, sesquichloride of iron; the last rendering the best results.
Example. A solution of 10 kilos. of tetraethyldiamido-diphenylmethan oxide in
about 200 litres of diluted sulphuric acid of 20% (such a solution can be obtained
by simply mixing the mass obtained in the second stage with water) is digested with
thirty litres of solution of sesquichloride of iron (of 1-14 sp. gravity) and 150 litres of
solution of chloride of zinc (sp. gravity 1.45), the whole is then heated for about
12 hours at about 90° Cent., until the formation of the colouring matter is finished.
After cooling, the dye-stuff is separated by filtering and well washed with solution
of salt.
The oxidation by means of peroxide of lead or nitrite must be effected in a weak
acid solution and in the cold.
Example, 2.7 kilos. of tetramethyldiamido-diphenylmethanoxide are dissolved hot in
120 litres of water and 4 kilos. of concentrated muriatic acid, the whole mass must
always be kept slightly aciduous, and, after cooling, an aqueous solution of nitrite is
added in the cold as long as any formation of colouring matter can be observed, which
can be tested by precipitating a sample and filtering it; if the filtrate on addition of
nitrite shows no further formation of colouring matter, the reaction is finished. This
operation requires about 0-8 kilo. of nitrite. The colouring matter obtained is then
precipitated with chloride of zinc and salt, and purified by crystallization in presence
of chloride of zinc.
The shade of the ethylated dye-stuff is a little more biueish than that of the methyl-
derivative.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed as communicated to me
by my foreign correspondent I declare that what I claim is :-
First The production of tetramethyl- or tetraethyldiamido-dioxidiphenylmethan by
the hereinbefore described process which consists in treating dimethyl- or diethyl-
inetaamidophenol with formaldehyde.

page_text: Second-Tetramethyl- or tetraethyldiamido-dioxidiphenylmethan prepared by treating
methyl- or diethylmetaamidophenol with formaldehyde.
Third The production of tetramethyl- or tetraethyldiamido-diphenylmethanoxide by
the hereinbefore described process which consists in treating tetramethyl- or tetraethyl-
diamido-dioxidiphenylmethan with dehydrating agents.
Fourth-Tetramethyl- or tetraethyldiamido-diphenylmethanoxide prepared by
treating tetramethyl or tetraethyldiamidodioxidiphenylmethan with dehydrating
agents.
Fifth The production of basic pink colouring matters by the herein before
described process which consists in treating the oxides mentioned in claim 3 and 4
with oxidizing agents.
Sixth Basic pink colouring matters prepared by treating the oxides mentioned
under claims 3 and 4 with oxidizing agents.
1 yea
1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.