Improvements in the Manufacture and Production of Sulpho Acids and of Colouring Matters.
Year: 1891

page_text: Date of Application, 4th Nov., 1891
Complete Specification Left, 4th Aug., 1892-Accepted, 15th Oct., 1892
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture and Production of Sulpho Acids
and of Colouring Matters.
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 Farbenfabriken vormals Friedrich Bayer
& Co., of Elberfeld, in the Empire of Germany,) to be as follows :—
I.
It is known that by heating methylbenzylaniline, ethylbenzylaniline or dibenzyl-
aniline with monohydrated sulphuric acid or by acting on them with fuming
sulphuric acid of moderate strength at a low temperature sulpho acids are formed
which contain the sulpho groups in the benzyl group.
My foreign correspondents have now found that the said amines yield new
sulpho acids when heated with fuming sulphuric acid of sufficient strength that is
to say that methylbenzylaniline and ethylbenzylaniline are changed into di- or
tri-sulpho acids and dibenzylaniline into a tri- or tetra-sulpho acid.
The production of these new sulpho acids can be carried out in the same
manner, in the case of the several bases; the following may be given as an
example.
MANUFACTURE OF ETHYLBENZYLANILINE DISULPHO ACID.
10 kilos of ethylbenzylaniline are introduced into 20 kilos of well cooled fuming
sulphuric acid containing about 20 per cent. of anhydride. When the ethylbenzyl-
aniline has dissolved the solution is mixed with 25 kilos of fuming sulphuric acid
containing 80 per cent. of anhydride and in order to complete the reaction the
liquid mixture is then heated to about 60 degrees centigrade. The formation of
the disulpho acid is judged to be complete when no precipitate is obtained on
treating a sample of the product with sodium sulphate in excess.
In contradistinction to the ethylbenzylaniline monosulpho acid the disulpho
acid thus produced dissolves very easily in water.
The strength of the fuming sulphuric acid and the temperature employed in the
process for producing these new sulpho acids can vary within wide limits.
The new methylbenzylaniline sulpho acids and dibenzylaniline sulpho acids are
formed in an analogous manner; they also dissolve with great readiness in water
and cannot be salted out by adding sodium sulphate in excess to their aqueous
Bolutions.
II.
The new sulpho acids of methyl- and ethylbenzylaniline and the new dibenzyl-
aniline sulpho acids before described enter very easily into action with tetraalkyl-
benzhydrols and their sulpho acids and yield leuco compounds.
These latter, by subsequent oxidation, can be transformed into new dyestuff
sulpho acids which afford shades characterised by their fastness in the presence of
alkalies. My foreign correspondents have obtained very valuable results by the
employment of the following benzhydrols, viz. :—
tetramethyldiamidobenzhydrol,
tetraethyldiamidobenzhydrol,
dimethyldiethrldiamidohenzhydrol.

page_text: diethyldibenzyldiamidobenzhydrol,
trimethylmonobenzyliamidobenzhydrol,
triethylmonobenzyldiamidobenzhydrol,
dimethylethylbenzyldiamidobenzhydrol,
diethylmethylbenzyldiamidobenzhydrol,
dimethyldibenzyldiamidobenzhydrol disulpbo acid,
diethyldibenzyldiamidobenzhydrol disulpho acid,
trimethylbenzyldiamidobenzhydrol monosulpho
acid,
triethylbenzyldiamidobenzhydrol monosulpho acid,
dimethylethylbenzyldiamidobenzhydrol monosulpho acid and
diethylmethylbenzyldiamidobenzhydrol monosulpho acid.
Colouring matters having similar properties are obtained by the action of
dimethylaniline meta sulpho acid, diethylaniline metasulpho acid, dimethyltoluidine
sulpho acid, diethyltoluidine sulpho acid dibenzylaniline disulpho acid and dibenzyl-
toluidine disulpho acid on the aforesaid hydrols and subsequently oxidising the
leuco compounds produced in the first instance.
The condensation of the hydrols or hydrolsulpho acids in question with the said
sulpho acids of dimethylaniline, diethylaniline, dimethyltoluidine, diethyltoluidine,
dibenzylaniline or dibenzyitoluidine is most practically effected by means of diluted
hydrochloric acid or sulphuric acid. The following may be given as an example
of the production of the said leuco compounds and their conversion into colouring
matters. by a subsequent oxidation.
COLOURING MATTER FROM TETRAMETHYLDIAMIDO BENZHYDROL AND
DIMETHYLANILINE META SULPHO ACID.
27 kilos of tetramethyldiamido benzhydrol are dissolved in 135 kilos of diluted
sulphuric acid containing 10 per cent. of acid and mixed with 20 kilos of dimethyl-
aniline meta sulpho acid dissolved in 80 kilos of water. The mixture is heated on
the water bath until the whole of the hydrol has entered into action with the
sulpho acid. Eventually the liquid is neutralized with sodium carbonate. On
cooling the sodium salt of the resulting leuco sulpho acid separates from the liquid
in characteristic lustrous scales. The product thus obtained is the monosulpho
acid of hexamethylparaleucaniline and this may be changed by oxidation with
lead dioxide into a blue colouring matter possessing both, basic and acid properties
suitable for dyeing cotton prepared with tannic acid and for dyeing wool in
a neutral bath, but less suitable for dyeing wool in acid baths. It produces
shades which are valuable on account of their fastness in the presence of
alkalies.
The colouring matters which contain benzyl groups obtained in an analogous
manner are not only fast in the presence of alkalies but also possess the property
of dyeing wool in acid baths.
The shades produced by all the dye-stuffs derived from the aforesaid hydrols are
from blue to violet.
Dated this 4th day of November 1901
COMPLETE SPECIFICATION.
Improvements in the Manufacture and Production of Sulpho Acids...
and of Colouring 'Matters.
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 5
communicated to me from abroad by The Farbenfabriken, vormals F. Bayer & Co.
of Elberfeld in the Empire of Germany).and in what manner. the same is to be

page_text: performed to be particularly described and ascertained in and by the following
statement:-
It is known that by heating methylbenzylaniline and ethylbenzylaniline with
monohydrated sulphuric acid or by acting on them with fuming sulphuric acid of
moderate strength at a low temperature sulpho acids are formed containing the
sulpho groups in the benzyl group.
My foreign correspondents have now found that the said amines yield new
sulpho acids when heated with fuming sulphuric acid of sufficient strength that.
is to say that methylbenzylaniline and ethylbenzylaniline are changed into
disulpho acids.
These new acids contain only one of the two sulpho groups in a benzyl group
one sulpho group having entered into the phenyl nucleus in a meta position to
the amido group.
3
The production of. these new sulpho acids from the said two tertiary amines can
be carried out in an analogous manner the following may be given as examples.
MANUFACTUre of ETHYLBENZYLANILINE DISULPHO ACID.
10 kilos of ethylbenzylaniline are introduced into 20 kilos of well cooled fuming
sulphuric acid containing about 20 per cent. of anhydride. When the ethyl-
benzylaniline has dissolved the solution is mixed with 25 kilos of fuming sulphuric
acid containing 80 per cent. of anhydride and in order to complete the action the
liquid mixture is then heated to 60 degrees centigrade. The formation of the
disulpho acid is judged to be complete when no precipitate is obtained on
treating with sodium sulphate in excess a sample of the product which has been
partially neutralized with sodium carbonate.
The whole mass is poured into water and the liquid is neutralized by means of
lime, the filtrate from the resulting calcium sulphate being then evaporated. The
product thus obtained is the calcium salt of the ethylbenzylaniline disulpho acid.
As this salt dissolves with very great readiness in water its watery solutions can be
evaporated until the liquid of a syrup-like consistency. After standing for some
time the syrup becomes solid. The barium salt obtained in an analogous manner
as the aforesaid calcium salt likewise dissolves with great readiness in cold water
but separates from a sufficiently concentrated solution in water in a crystallized
form. My foreign correspondents have ascertained by an analytical examination
of this barium salt that it is derived from a disulpho acid.
By boiling the said calcium or barium salt with alkaline carbonates the corre-
sponding alkaline salts are produced which though very easily soluble in water can
be salted out by means of common salt or potassium chloride. When concentrated
soda-lye is added to the solutions of the said alkaline salts these latter are
gradually precipitated in a crystalline form. Whereas however the addition of
hydrochloric acid to the watery solutions of ethylbenzylaniline monosulpho acid
causes the acid to separate, the ethylbenzylaniline disulpho acid cannot be
precipitated in this manner.
My foreign correspondents have ascertained the position of the sulpho groups by
beating the sodium salt of this sulpho-acid with double its weight of sodium
hydroxide or potassium hydroxide and a little water until the addition of hydro-
chloric acid to a sample of the melt caused a copious disengagement of sulphurous
acid. On dissolving the melt in water acidulating with hydrochloric acid and then
rendering the liquid alkaline by the addition of sodium carbonate, a brown thick
oil, insoluble in water and sodium carbonate, but readily soluble in soda-lye and
alcohol, was separated and by heating this oil with an excess of phtalic anhydride
and some zinc chloride a rhodamine was obtained the alcoholic solution of which
was of a red colour exhibiting a brilliant green fluorescence. As it is known that.
only derivatives of meta amidophenol yield rhodamines this result proves that the

page_text: ethylbenzylaniline disulpho acid contains one sulpho group in the phenyl nucleus in
the meta position relatively to the amido group. Methylbenzylaniline disulpho
acid is obtained in a manner analogous to that by which the aforesaid ethylbenzyl-
aniline sulpho acid is produced. Both the acids and their salts are very similar.
The said disulpho acids can of course be produced be employing instead of
methyl or ethylbenzylaniline the corresponding monosulpho acids viz. methyl-
benzylaniline monosulpho acid and ethylbenzylaniline monosulpho acid.
The strength of the fuming sulphuric acid and the temperature employed in the
process for producing these new sulpho acids can vary within wide limits.
The new sulpho acids of methyl and ethylbenzylaniline above described very
easily interact with tetraalkyldiamidobenzhydrols yielding leuco compounds.
These latter can be transformed by subsequent oxidation into new dye-stuff sulpho
acids affording shades characterized by their fastness in the presence of alkalies.
The new dye-stuffs thus obtainable also differ from the analogous acid violets by
the possession of the property of retaining their beautiful bluish violet shades in
artificial light and of exhibiting no fluorescence on fibres when dyed together with
yellow colouring matters. My foreign correspondents have obtained very valuable
results by the employment of the following benzhydrols viz.
tetramethyldiamidobenzhydrol,
tetraethyldiamidobenzhydrol,
dimethyldiethyldiamidobenzhydrol,
dimethyldibenzyldiamidobenzhydrol,
diethyldibenzyldiamidobenzhydrol,
trimethylmonobenzyldiamidobenzhydrol,
triethylmonobenzyldiamidobenzhydrol,
dimethylethylbenzyldiamidobenzhydrol,
diethylmethylbenzyldiamidobenzhydrol.
Colouring matters having similar properties are obtained by the action of
dimethylaniline-meta-sulpho acid, diethylaniline-meta-sulpho acid, dimethyl-
toluidine-sulpho acid, diethyltoluidine-sulpho acid, dibenzylaniline-disulpho acid,
and dibenzyltoluidine-disulpho acid on the aforesaid hydrols and subsequently
oxidizing the leuco compounds which are produced in the first instance.
The condensation of the hydrols in question with the said sulpho acids of
dimethylaniline, diethylaniline, dimethyltoluidine, diethyltoluidine, dibenzylaniline,
or dibenzytoluidine, and the like, is most practically effected by means of diluted
hydrochloric acid or sulphuric acid. The following may be given as examples of
the production of the said leuco compounds and their conversion into colouring
matters by a subsequent oxidation.
DYE STUFF PRODUCED BY COMBINING TETRA-METHYL-DIAMIDO-BENZHYDROL
:
WITH METHYL-BENZYL-ANILINE-DISULPHO ACID AND SUBSEQUENTLY
OXIDISING THE LEUCO COMPOUND THUS OBTAINED.
27 kilos of tetra-methyl-diamido-benzhydrol are dissolved in 400 kilos of sulphuric
acid (containing 5 per cent. of H₂SO) and after adding 40 kilos of the dry sodium
salt of methyl-benzyl-aniline-disulpho acid the mixture is heated on the water bath
until the tetra-methyl-diamido-benzhydrol employed is no longer distinguishable.
The liquid is then neutralised with sodium carbonate and the leuco compound is
precipitated by salting out with sodium sulphate. It is re-dissolved in 200 kilos
of acetic acid (containing 50 per cent. of acid) and 48 kilos of a lead dioxide paste
(containing 50 per cent. of PbO,) are stirred in, to oxidise the said leuco product.
When the oxidation is complete the lead is precipitated by the addition of diluted
sulphuric acid and, after filtering off the lead sulphate, the resulting filtrate is mixed
with a sufficient quantity of sodium sulphate to precipitate the colouring matter

page_text: THIRD EXAMPLE.
COLOURING MATTER FROM TETRA-METHYL-DIAMIDO-BENZHYDROL AND
DIMETHYL-ANILINE-META-SULPHO ACID.
27 kilos of tetra-methyl-diamido-benzhydrol are dissolved in 135 kilos of diluted
sulphuric acid (containing 10 per cent. of acid) and mixed with 20 kilos of dimethyl-
aniline meta-sulpho acid dissolved in 80 kilos of water. The mixture is heated on
the water bath until the whole of the hydrol has entered into action with the sulpho
acid. The liquid is then neutralized with sodium carbonate. The sodium salt of
the resulting leuco sulpho acid separates from the liquid, as it cools, in characteristic
lustrous scales. This product is the monosulpho acid of hexamethylparaleucaniline
and may be converted by oxidation with lead dioxide into a blue colouring matter
in the following manner. The leuco sulpho acid obtained in the manner described
is dissolved in 200 kilos of acetic acid (containing 50 per cent. of acid) and 48 kilos
of a lead dioxide paste (containing 50 per cent. of PbO2) are stirred into the liquid.
The formation of the dye-stuff is complete after a few minutes. The lead is pre-
cipitated by the addition of 20 kilos of sulphuric acid at 66 degrees Baumé and
after filtering off the lead sulphate the filtrate is evaporated in order to separate
the dissolved dye stuff. The latter possesses both basic and acid properties and is
suitable for dyeing cotton prepared with tannic acid and for dyeing wool in a
neutral bath but less suitable for dyeing wool in acid baths. It produces shades
which are valuable on account of their fastness in the presence of alkalies.
Colouring matters are produced in an analogous manner from tetraethyldiamido-
benzhydrol or the other above named alkylised diamidobenzhydrols or the other
sulpho acids above mentioned. All these products are of high value as they with-
stand alkalies.
The colouring matters which contain benzyl groups are not only fast in the
presence of alkalies but also possess the property of dyeing wool in acid baths.
The shades produced by all the dye-stuffs derived from the aforesaid hydrols are
from blue to violet.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed I declare that what I claim is :-
First. The process of producing methylbenzylaniline-disulpho-acid and ethyl-
benzylaniline-disulpho acid by heating methylbenzylaniline, ethylbenzylaniline, or
the mono-sulpho acids thereof, with fuming sulphuric acid as hereinbefore described.
Second. The process of obtaining leuco compounds containing sulpho groups and
belonging to the triphenylmethane series by acting with methylbenzylaniline-
disulpho acid, ethylbenzylaniline-disulpho acid, dimethylaniline-meta-sulpho acid,
diethylaniline-meta-sulpho acid, dimethyl-ortho-toluidine-meta-sulpho acid, diethyl-
ortho-toluidine-meta-sulpho acid, dibenzyl-aniline-disulpho acid, or dibenzyl-ortho-
toluidine-disulpho acid, on the following alkylised diamido benzhydrols:
tetramethyldiamidobenzhydrol,
tetraethyldiamidobenzhydrol,
dimethyldiethyldiamidobenzhydrol,
dimethyldibenzyldiamidobenzhydrol,
diethyldibenzyldiamidobenzhydrol,
trimethylmonobenzyldiamidobenzhydrol,
triethylmonobenzyldiamidobenzhydrol,
dimethylethylbenzyldiamidobenzhydrol,
diethylmethylbenzyldiamidobenzhydrol.

page_text: 3. The process of transforming the leuco sulpho acids described in the preceding
second claim into the corresponding dye-stuffs by oxidation.
4. As new manufactures:
a, methylbenzylaniline disulpho acid.
b, ethylbenzylaniline disulpho acid.
C,
the new leuco compounds and dye-stuffs having the properties herein before
described.
B. WILLCOX,
47, Lincoln's Inn Fields.

page_text: Date of Application, 4th Nov., 1891
Complete Specification Left, 26th July, 1892-Accepted, 27th Aug., 1892
COLOURING MATTER FROM TETRAMETHYLDIAMIDOBENZHYDROL AND PARA-
TOLYLALPHANAPHTHYLAMINE.
-
24-2 kilos. of the leuco compound formed by condensing tetramethyldiamido-
benzhydrol with paratolylalphanaphthylamine in alcoholic solution in the presence
of diluted muriatic acid, are dissolved in a mixture of 140 kilos. of 50 per cent. acetic
acid and 20 kilos. of hydrochloric acid (specific gravity 1.18). The resulting
solution is diluted with such a quantity of water that the whole volume is 2000 litres.
This liquid having been cooled has slowly stirred into it 34-5 litres of a solution of
sodium nitrite containing 10 per cent. of nitrite.
The formation of the nitroso amine derivative takes place almost immediately and
it is produced in theoretical amount. In the next place it is oxidised by means of
39.6 kilos. of a lead dioxide paste containing 30 per cent. of lead dioxide in the usual
manner and after the lead has been separated and filtered off the intense green
solution of the nitroso dye-stuff is heated on the water bath in order to remove the
nitroso group. The conversion is complete after heating for a few hours and a pure
blue solution is obtained from which the new dye-stuff separates on cooling in golden
lustrous crystals.
This new product is difficultly soluble in cold but easily soluble in hot water, and
produces on wool or cotton, prepared with tannic acid, a pure blue colour whilst the
dye stuff obtained when the condensation product is oxidised without having been
previously changed into its nitroso compound yields only dull tones of no practical
value.
The oxidation product differs from the nitroso amine compound by yielding pure
blue shades, the latter producing on wool and cotton green shades which are
less fast.
The removal of the nitroso group from the nitroso compound of the dye-stuff
may also be effected by means of alkalies or by aniline or substances acting in a
similar manner.
Instead of tetramethyldiamidobenzhydrol the analogues compound tetraethyldi-
amidobenzhydrol can be employed and the following secondary amines may be used

page_text: in place of paratolylalphanaphthylamine viz. : monomethylaniline, monoethylaniline,
monobenzylaniline diphenylamine,monomethylalpha naphthylamine,monoethylalpha-
naphthylamine, monobenzylalphanaphthylamine, phenylalphanaphthylamine, ortho-
and paratolylalphanaphthylamine or dinaphthylamine.
The colouring matters which are formed by the before described process are not
identical but isomeric with those described in the Specification of the German
Patent No. 27789.
Dated this 7th day of December 1801
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Colouring Matters.
I BENJAMIN WILLCOX of 47 Lincolns 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 Farbenfabriken vormals Friedrich Bayer
& Co. of Elberfeld 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 :—
Primary secondary and tertiary aromatic amines can it is known be condensed
with the tetra alkylised diamido benzhydrols leuco bases of the rosaniline series
being produced. Although the leuco compounds formed from tertiary amines are
very easily oxidised to form colouring matters the oxidation proceeds in a less simple
manner and yields a considerably smaller quantity of the dye stuff when the leuco
products obtained from tetraalkylised benzhydrols and primary or secondary aromatic
amines are employed.
My foreign correspondents have discovered that leuco compounds resulting from
the condensation of secondary amines with tetra-alkylised benzhydrols may be
-oxidized with the greatest ease if the hydrogen atom of the amido group be
displaced in the well known manner by the nitroso group and the resulting nitroso
leuco compounds be subjected to oxidation. The said leuco compounds in general
are dissolved in acetic acid and after adding a mineral acid a solution of sodium
nitrite is added. When the reaction is complete the oxidation is effected in the
usual manner. The products thus obtained which belong to the nitroso amine series
can be converted into dye-stuffs by subsequently removing the nitroso group viz. by
heating the resulting nitroso compounds in watery solution with or without the
.addition of acids or alkalies.
In order to avoid oxidation by the nitrous acid which is disengaged it is desirable
to effect the reaction in the presence of aromatic bases such for example as aniline,
toluidine or of moderately powerful reducing agents (sulphurous acid and the like).
The separation of the nitroso group especially in strong acid solution can be effected
in such cases at ordinary temperature and in a short time.
This new process may be explained by the following examples :-

page_text: The formation of the nitroso amine derivative takes place almost immediately
and it is produced in theoretical amount. In the next place it is oxidized by means
of 39-6 kilos. of a lead dioxide paste containing 30 per cent. of lead dioxide in the
usual manner and after the lead has been separated and filtered off the intense
green solution of the nitroso dyestuff is heated on the water bath in order to
remove the nitroso group. The conversion is complete after heating for a few
hours and a pure blue solution is obtained from which the new dyestuff separates on
cooling in golden lustrous crystals.
This new product is difficultly soluble even in hot water and produces on
wool or cotton prepared with tannic acid a pure blue colour whilst the dye-
stuff obtained when the condensation product is oxidized without having been
previously changed into its nitroso compound yields only dull tones of no practical
value.
The oxidation product differs from the nitroso amine compound by yielding
pure blue shades the latter producing on wool and cotton green shades which
are less fast.
The removal of the nitroso group from the nitroso compound of the dye stuff may
also be effected by means of alkalies or by aniline or reducing substances acting in
a similar manner such as sulphurous acid and the like as described in the following
example
amine.
SECOND EXAMPLE.
Dyestuff obtained from tetramethyldiamidobenzhydrol and phenylalphanaphthyl-
47.1 kilos. of the leuco base obtained from tetramethyldiamidobenzhydrol and
phenylalphanaphthylamine in alcoholic solution and in presence of muriatic acid
are dissolved in 200 kilos. of acetic acid containing 50 per cent. of pure acid with the
addition of 40 kilos. of muriatic acid (specific gravity 1.18) and 400 kilos. of water.
The solution thus obtained after cooling is mixed with 69 litres of a 10 per cent.
solution of sodium nitrite in water and the resulting nitroso amine leuco compound
is oxidized by means of 79.3 kilos. of a lead dioxide paste containing 30 per cent.
of PbP,. After precipitating the lead from the deep green solution by means of
diluted sulphuric acid (an amount corresponding to 10 kilos. of pure sulphuric
acid) about 500 litres of a watery solution (6 per cent.) of sulphurous acid are added
and the mixture is added with constant agitation to an equal volume of strong
muriatic acid whereby the removal of the nitroso group is effected. When
after some hours standing the solution shews no further change in colour it is poured
into hot water and the free mineral acids are neutralized by the addition of alkalies
or sodium acetate. The colouring matter is thereby separated in a crystalline state
and in good amount. It can be purified by redissolving in acids and precipitating
by means of alkalies and is identical with the product known in commerce as
Victoria blue B.
Instead of tetramethyldiamidobenzhydrol of the foregoing examples the
analogous compounds tetraethyldiamidobenzhydrol and the like can be employed
and the following secondary amines may be used in place of paratolyl or phenyl-
alphanaphthylamine viz. monomethylaniline monoethylaniline, monobenzylaniline
diphenylamine mono-methylalphanaphthylamine mono-ethylalphanapthylamine
mono-benzylalphauaphthylamine ortho and paratolylalphanaphthylamine or dinaph-
thylamine.
The shades produced by all these colouring matters on wool or cotton prepared
with tannic acid are in general from violet to blue or greenish blue.
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 :-
First The process of producing leuco compounds containing a nitrosoamine group

page_text: and belonging to the triphenylmethane or diphenylnaphthylmethane series by
treating with nitrous acid the leuco products which result from the combination of
tetraalkylised diamido benzhydrols with secondary amines such as for example
mono-methylaniline monoethylaniline, mono-benzylaniline diphenylamine, mono-
methylalphanaphthylamine mono-ethylalphanaphthylamine mono-benzylalpha-
naphthylamine phenylalphanaphthylamine ortho and paratolylalphanaphthylamine
dinaphthylamine.
Second-The transformation of the leuco compounds defined in the preceding
first claim into colouring matters likewise containing a nitroso amine group by
oxidizing the said leuco base products.
Third The process of producing dyestuffs by splitting off the nitroso group
from the products defined in the foregoing second claim.
1
T11000
J. H. JOHNSON & Co.,
Agents.