Improvements in the Manufacture of Colouring Matter and of Leuco Bases employed therein.
Year: 1889

page_text: Date of Application, 24th May, 1889
Complete Specification Left, 24th Mar., 1890-Accepted 3rd Mav. 1890
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Colouring Matter and of Leuco
Bases employed therein.
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) to be as follows:-
According to this Invention leuco bases of the tri-phenyl methane group are obtained.
by taking benzaldehyde or a benzaldehyde substituted in the neucleus such as nitro
benzaldehyde, amido benzaldehyde, alkylised amido benzaldehyde, oxy benzaldehyde,
chloridised benzaldehyde on the one hand and m amido phenol or its alkylised
derivatives in the NH₂ group or its salts or m oxy diphenylamine on the other hand.
and melting them together at the temperature of a water bath in the presence of,
dehydrating agents such as concentrated sulphuric acid or preferably chloride
cf zinc:
Red colouring matters are obtained by further treating the leuco base or product of
this operation with dehydrating agents such as concentrated sulphuric acid or chloride
of zinc at a temperature of from about 160 to 200 degrees Centigrade.
To obtain a red basic colouring matter the following ingredients are taken
namely: :-
On the one hand.
Methylene chloride-bromide-iodide.
Acetone.
Chloroform.
On the other hand.
m oxydimethyl aniline
or ..
m oxydiethyl aniline.
These materials are (a) heated to from about 130 to 180 degrees Centigrade with or
without the employment of condensing agents such as zinc chloride or concentrated
sulphuric acid or (b) the new base formed in the first instance with or without the
employment of condensing agents is further treated with concentrated sulphuric acid
at about 160 degrees Centigrade.
A new basic red colouring matter is obtained according to this Invention as
follows:
(a) Oxy chloride of carbon or phosgene is caused to act upon m amido phenol
alkylised in the NH, group under pressure at a temperature of about 180 degrees
Centigrade and the resulting dioxy tetra methyl diamido benzo phenone is treated
with dehydrating agents such as sulphuric acid zinc chloride and the like.
(b) Acetaldehyde (paraldehyde) is caused to act upon m amido phenols alkylised
in the NH, group or on its salts, at a temperature of from about 170 to 180 degrees
centigrade with the addition of condensing agents.
(c) Unsymmetrical diphenyl tri chlorethane or unsymmetrical diphenyl dichlor-
ethylene on the one hand is caused to act upon m amido phenol alkylised in the NH,
group on the other hand at a temperature of from about 150 to 160 degrees Centigrade
with or without the employment of condensing agents such as aluminium chloride,
chloride of zinc and the like.
(d) Benzal chloride or benzo tri chloride on the one hand is caused to act upon
m amido phenol alkylised in the NH, group, on the other hand at or under 60 degrees
Centigrade with or without the employment of condensing agents.
(e) Free formic acid or a mixture of glycerine and oxalic acid is caused to act
upon m amido phenol alkylised in the NH, group with the employment of condensing
agents such as zinc chloride for example.

page_text: The manufacture of these colouring matters and materials is further described by
my foreign correspondence as follows:-
It is known that aromatic aldehydes can be readily condensed with certain aromatic
bases or the salts thereof in the presence of condensing agents to form leuco bases of
the triphenylmethane group. The action of aldehydes upon aromatic bases in which
one or more hydrogen atoms of the benzene neucleus are replaced by hydroxyl
groups has not hitherto been studied.
My foreign correspondents have now discovered that the condensation of aromatic
aldehyde with aromatic bases in which hydroxyl occupies the meta position or
with m amido phenol or its derivatives proceeds well and smoothly with formation
of leuco bases.
Two molecules of the amido phenol are used on one molecule of the aldehyde. The
operation may be performed either in an alcoholic chloride of zinc solution in an
anhydrous vinegar solution with the addition of a small quantity of concentrated
sulphuric acid or zinc chloride or with a small quantity of concentrated hydrochloric
acid and zinc chloride or again simply with concentrated sulphuric acid at the
temperature of a water bath.
As the reaction is not properly completed until after about twenty four hours, it
is desirable in order to avoid oxidation of the aldehyde with the oxygen of the
atmosphere or its evaporation with the escaping water to operate either in closed
vessels or by introducing the aldehyde very gradually.
The formation of the leuco base proceeds according to the general equation.

page_text: When the heating has been continued for too long a time the shade of the resulting
colouring matter is yellower and duller, the fluorescence being greener and likewise
duller whereas the alcoholic solution of the product when the operation has been
properly conducted is of a pure blue red and has a fiery yellow fluorescence.
The process that takes place consists in an inter molecular splitting off of water
and is represented by the following equation.
The melt is poured into a small quantity of water boiled and, when zinc chloride
has been employed as the condensing agent the colouring matter is precipitated with
common salt.
When sulphuric acid is employed the greater quantity of the acid is neutralised
with soda or lime and after filtering the colour base is thrown down with ammonia.
The latter is then dissolved with the calculated quantity of hydrochloric acid and a
small quantity of water and the colouring natter is precipitated by the addition
of Zn Cl, and Na Cl. The colouring matter thus obtained being dried at 60 degrees
Centigrade is in the form of a dark powder with a bronze lustre the watery and
alcoholic solutions of which are more or less vividly fluorescent.
These products dye animal fibre and vegetable fibre (treated with tannic acid) in
the same way as rhodamine and develope on silk especially a red of the most
splendid fluorescence.
The isolation of the leuco base as herein before described is not absolutely
necessary.
The actual coupling of the two components and the internal condensation can
be effected in one operation by proceeding as follows for example.
1 molecule of aldehyde.
2 molecules of amido phenol dissolved in the calculated quantity of concentrated
hydrochloric acid, and
3 times the weight of the aldehyde of zinc chloride―
are heated for about 24 hours to a temperature of about 100 degrees Centigrade..
The materials being stirred the temperature is slowly raised to about 150 degrees
and finally to about 200. The splitting off of the second molecule of water with
direct formation of the colouring matter then takes place.
The following may be taken as examples of this manufacture.
About 106 parts by weight (106 kilos.) of benzoldehyde are very gradually intro-
duced in the course of about twelve hours into a solution heated to 100 degrees of
about 27.4 parts by weight (27.4 kilos.) of m oxydimethyl aniline and about 30
parts by weight (30 kilos.) of zinc chloride in about 22 parts by weight (22 kilos.)

page_text: of concentrated hydrochloric acid (of about 33 per cent. strength). After frequent
stirring being maintained at the temperature of a water bath for another 12 hours
the yellowish brown melt is gradually heated to about 200 degrees.
The red melt obtained by this method is then subjected to further treatment as
herein before described. When working with closed vessels, the whole of the
aldehyde may be introduced at once.
According to another example
About five parts by weight (5 kilos.) of p dimethyl amido benzoldehyde.
About eleven parts by weight (11 kilos.) of m oxydiethyl aniline and
About forty parts (40 kilos.) of concentrated sulphuric acid-
are heated to 100 degrees Centigrade for from about two to three hours and then
maintained at from about 140 to 150 degrees Centigrade until a sample being
poured into a small quantity of cold water and,mixed with alcohol displays the
desired colour and fluorescence. The actual colouring matter is obtained as
herein before described.
There are several publications relating to processes connected with the production
of multiple halogen substituted méthane upon dimethyl aniline or diethyl aniline.
These reactions can be produced with the employment of m oxy dimethyl aniline
m oxy diethyl aniline and m oxy diphenylamine.
My foreign correspondents have discovered that good results are obtained by the
action of one molecule of methylene chloride or acetone on the one hand upon two
molecules of m oxy dimethyl aniline or m oxy diethyl aniline on the other hand at
temperatures of from about 130 to 180 degrees Centigrade. In the first place there
is formed the hydrochloric acid salt of the corresponding dihydroxylised tetra methyl
diamido diphenylene methane or its derivatives replaced (substituted) by 2Ch 3 groups
in the methylene rest.
When these salts are slowly introduced into from 4 to 5 times the quantity of
'concentrated sulphuric acid hydrochloric acid gas is generated and after heating for
about half an hour to from about 150 to 160 degrees Centigrade and pouring the
melt into water, red and highly fluorescent solutions of colouring matter are obtained
which are transformed into dyes in the usual manner. The new substances thus
obtained appear to resemble rhodamine.
This process may be conducted as follows-
About 34 parts by weight (3.4 kilos.) of methylene chloride and about 11 parts
by weight (11 kilos.) of m oxy dimethyl aniline are heated under pressure for about
3 or 4 hours to from about 130 to 140 degrees Centigrade and then slowly intro-
duced into about 60 parts by weight (60 kilos.) of concentrated sulphuric acid of about
66 degrees Baumé whereupon streams of hydrochloric acid gas are given off. After
heating to about 160 degrees Centigrade for about half an hour the materials are
poured into about 200 parts by weight (200 litres) of cold water and the excess of
soda lve is precipitated.
The liquid is decanted from the resinous separated base which is then dissolved in
about 9 parts by weight (9 kilos.) of hydrochloric acid (at 33 per cent.) and 50 parts
(or 50 litres) of water. The colouring matter is then separated by means of zinc
chloride and common salt in the form of a double salt of chloride of zinc. The
precipitate being resinous at first solidifies into a crystalline form after about 24 hours
and is dried preferably at a temperature of from about 30 to 40 degrees Centigrade.
The colouring matter thus obtained is in the form of a green, bronze lustrous powder
readily soluble in cold water and dyes animal fibre and vegetable fibre (treated with
tannic acid) in the same way as rhodamine.
According to another method about 10-5 parts by weight (10.5 kilos.) of acetone,
57 parts (57 kilos.) of m oxy diethyl aniline and 30 parts (30 kilos.) of zinc chloride
are intimately mixed and heated to about 180 degrees Centigrade in a closed vessel
for about 12 hours. After cooling and opening the vessel the excess of acetone is
driven off by heat. The mass is then dissolved in hot and highly diluted hydrochloric
acid and the resulting base is precipitated with acetate of soda, After filtering out

page_text: the resinous base is dissolved in about 200 parts by weight of concentrated sulphuric-
acid and heated to about 160 degrees Centigrade for half an hour. The melt after
being poured into water is further treated as in the preceding example.
My foreign correspondents have also discovered that the reaction may be extended
to the treatment of aldehydes of the fatty group as ascetic aldehyde (paraldehyde)
formic acid, oxy chloride of carbon, benzal chloride, benzo tri chloride, the diphenyl
tri chlorethane obtained from chloral and the di-phenyl di-chlorethylene obtained from
this chlorethane.
The condensation with alkylised m amido phenols is proceeded with in either open
or closed vessels according to the nature of the materials with or without the employ-
ment of condensing agents and generally at a high temperature between about 100
and 200 degrees Centigrade. The reaction is proportionately easier when two
halogen atoms of one molecule of one of the components act upon two hydrogen
neucleus atoms of two molecules of the above mentioned aromatic bases with the
formation of 2 molecules of oxy chloride of carbon.
The reaction proceeds with difficulty and only with the aid of condensing agents
when aldehydes of the fatty group are employed one oxygen atom of the aldehyde
being caused to react upon two hydrogen neucleus atoms of two molecules of the
aromatic base with the formation of one molecule of water.
On the other hand all those substances (except chloroform which reacts with more
difficulty) in whose molecules not 2 only but 3 affinities of the same hydrogen atoms
are replaced by elements or groups capable of reaction such as halogen oxygen
hydroxyl and the like, are condensed with great ease.
The yield in this case is very profitable the crude product being of remarkable
purity.
These substances are benzo trichloride diphenyl chlorethane, formic acid and the
like.
Whilst phosgene, benzal chloride, unsymmetrical diphenyl dichlor ethylene afford
a satisfactory yield of colouring matter only with the employment of condensing
agents such as aluminium chloride zinc chloride etc., benzo trichloride reacts at from
about 30 to 40 degrees Centigrade and unsymmetrical diphenyl trichlor ethane reacts
at melting temperature and form large quantities of red colouring matter.
When m oxy dimethylaniline is employed violent reactions take place readily when
heated too quickly. Excessive heat leads either to the production of spirit soluble
rhodamine like colouring matter or to no transformation whatever of the red
colouring matters into useful orange yellow dyes which in solution also present
intense Buorescence. The red colouring matters obtained from diphenyl trichlor
ethane and diphenyl dichlor ethylene are directly spirit soluble.
Next to the synthesis obtained with the aid of benzo tri chloride by far the
greatest interest is attached to those in which formic acid is employed. The capacity
of formic acid of condensing with alkylised m amido phenols is due to a certain
analogy to the aldehydes. All other higher fatty acids such as acetic acid for example
do not condense.
When for example any alkylised m amido phenol is heated with glycerine and
oxalic acid, both of which are preferably dehydrated before hand, and with a smal!
quantity of chloride of zinc the temperature being gradually raised to from about
110 to 120 degrees Centigrade the inaterials assume at first a blue colour. On
heating to a higher degree the mass becomes of a beautiful violet colour which at
from about 220 to 230 degrees Centigrade changes to a fiery red. The colouring
matter is precipitated in a state of almost chemical purity by means of common salt
and zinc chloride after the melt has been poured into water.
The colouring matters thus obtained are of a similar nature to rhodamine. Those
obtained from m oxy dimethyl aniline are red with a yellow tinge, those from
m oxydiethyl aniline blueish red and those from m oxydiphenylamine a dull violet red.
The latter are insoluble in water but readily soluble in spirit.
The following is given as an example-
About 7 parts by weight (7 kilos.) of m. oxy dimethyl aniline are dissolved in

page_text: $
about 5-6 parts by weight of hydrochloric acid of 33 per cent. strength. The water
is evaporated and the materials are then heated in a closed vessel to from about 170
to 180 degrees Centigrade for from about 8 hours with about 12 parts by weight of
paraldehyde & 40 parts of zinc chloride.
. After cooling the contents of the vessel are boiled down with a small quantity of
water slightly acidulated with hydrochloric acid, allowed to cool and the chloride of
zine and the mother liquor containing a quantity of unchanged m oxy dimethyl
aniline is separated from the colouring matter by filtration.
The colouring matter is dissolved in hot water and precipitated with a small
.quantity of zinc chloride and common salt after filtering.
According to another example about 6.6 parts by weight (66 kilos.) of m oxy
diethyl aniline: are carefully stirred into about 1.5 parts by weight (15 kilos.) of
benzo trichloride and slowly heated to from about 30 to 40 degrees Centigrade.
When the melt has assumed a strong red colour about 24 parts by weight (24 kilos.)
of benzo trichloride are added care being taken that the heat resulting from the
reaction is not allowed to exceed about 60 degrees Centigrade. The melt is. then
maintained at from about 50 to 60 degrees Centigrade for about 2 hours after which
it is dissolved in hot water and the colouring matter is precipitated with zinc chloride
and common salt.
According to another example, into a mixture of about 6.2 parts by weight
(6·2 kilos.) of unsymmetrical diphenyl dichlor ethylene and about 7 parts by weight
(7 kilos.) of m oxy dimethyl aniline there is very gradually introduced (with stirring)
about two parts by weight (2 kilos.) of dehydrated aluminium chloride. The melt of
, colouring matter produced is dissolved in spirit and the spirit soluble red colouring
matter is precipitated with water.
. According to another example a mixture composed of about eleven parts by weight
(11 kilos.) of m oxy diethyl aniline about 9 parts by weight (9 kilos.) of dehydrated
oxalic acid, about five parts by weight (5 kilos.) of dehydrated glycerine and about
6 parts by weight (6 kilos.) of zinc chloride is gradually heated to from about 80 to
90 degrees.
1
When the violent evolution of carbonic acid is over the materials are slowly heated
for a time in an open vessel to from about 110 to 120 degrees Centigrade after which
the temperature is slowly raised with stirring to from about 220 to 230 degrees
Centigrade. After cooling the melt is poured into hot water acidulated with
hydrochloric acid and salted out with common salt.
Dated this 04th d... is Ma– 1000
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Colouring Matter and of Leuco
Bases employed therein.
1, 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 com-
municated to me from abroad by 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:—
According to this Invention leuco bases of the tri-phenyl-methane group are
obtained by taking benzaldehyde or a benzaldehyde substituted in the nucleus such as
nitro-benzaldehydes, amido-benzaldehydes, alkylised-amido-benzaldehydes, hydr-oxy-
benzaldehydes, chlorinated benzaldehydes on the one hand and meta-amido-phenol
alkylised in the NH, group or its salts or meta-hydroxy-diphenylamine on the other
hand and melting them together at the temperature of a water bath in the presence of
dehydrating agents such as concentrated sulphuric acid or preferably chloride
of zinc,

page_text: Red coloring matters are obtained by further treating the leuco base or product of
this operation with dehydrating agents such as concentrated sulphuric acid or chloride
of zinc at a temperature of from about 160 to 200 degrees Centigrade.
To obtain a red basic colouring matter the following ingredients are taken
namely:-
་་
These materials are heated to from about 130 to 180 degrees Centigrade with, or
without, the employment of condensing agents such as zinc-chloride or concentrated
sulphuric acid or the new base formed in the first instance with, or without, the
employment of condensing agents is further treated with concentrated sulphuric acid
at about 160 degrees Centigrade. If di-ketones be employed one molecular proportion
is caused to react upon 4 molecular proportions of a meta-amido-phenol.
A new basic red colouring matter is obtained according to this invention as
follows:
**
:-
'
(a) Oxy-chloride of carbon or phosgene is caused to act upon meta-amido-phenol
alkylised in the NH, group under pressure at a temperature of about 180 degrees
Centigrade and the resulting dihydroxy-tetra-methyl-diamido-benzo-phenone is
treated with dehydrating agents such as sulphuric acid, zinc chloride and the like.
(b) Formaldehyde or acetaldehyde (paraldehyde) is caused to act upon meta-amido-
phenols alkylised in the NH, group, or on their salts, at a temperature of from about
170 to 180 degrees Centigrade with the addition of condensing agents.
(c) Unsymmetrical diphenyl-trichlorethane or unsymmetrical diphenyl-dichlor-
ethylene, is caused to act upon meta-amido phenol alkylised in the NH, group, at a
temperature of from about 150 to 160 degrees Centigrade, with or without the
employment of condensing agents, such as aluminium-chloride, chloride of zinc and
the like.
(d) Benzalchloride, benzo-trichloride is caused to act upon meta-amido-phenol
alkylised in the NH, group at, or under, 60 degrees Centigrade with or without the
employment of condensing agents.
(e) Free formic acid or a mixture of glycerine and oxalic acid is caused to act
upon meta-amido-phenol, alkylised in the NH, group with the employment of con-
densing agents such as zinc-chloride for example.
The manufacture of these colouring matters and materials is further described by
my foreign correspondents as follows
It is known that aromatic aldehydes can be readily condensed with certain aromatic
bases or the salts thereof in the presence of condensing agents to form leuco bases of
the triphenyl-methane group. The action of aldehydes upon aromatic bases, in which
one or more hydrogen atoms of the benzene neucleus are replaced by hydroxyl groups
has not hitherto been studied.
My foreign correspondents have now further discovered that the condensation of
aromatic aldehydes with aromatic bases in which hydroxyl occupies the meta position
or with meta-amido-phenol or its derivatives proceeds well and smoothly with
formation of leuco-bases.
;

page_text: Two molecular proportions of the amido phenol alkylised in the NH, group are
used to one molecular proportion of the aldehyde. The operation may be performed
either in an alcoholic chloride of zinc solution, or in an anhydrous acetic solution with
the addition of a small quantity of concentrated sulphuric acid or zinc chloride or
with a small quantity of concentrated hydrochloric acid and zinc chloride or again
simply with concentrated sulphuric acid at the temperature of a water bath.
As the reaction is not properly completed until after about twenty four hours, it is
desirable, in order to avoid oxidation of the aldehyde by the oxygen of the atmo-
sphere or its evaporation with the escaping water, to operate either in closed vessels
or to introduce the aldehyde very gradually.
The formation of the leuco base proceeds according to the general equation.
CH3
C₂ H
NO,; NH; N
; N
; OH; CH3;
CH3
C₂ H
bave been introduced. R₁₁ representing any fatty alkyl or aromatic hydrocarbon
radicle and R representing a hydrocarbon radicle or fatty alkyl.
When the reaction is concluded the yellow brown melt is dissolved' in water, the.
greater part of the acid neutralised with soda lye and the base precipitated with
acetate of soda.
After washing and pressing the leuco base is dissolved in a small quantity of con-
centrated bydrochloric acid and mixed with twice its weight of chloride of zinc or
dissolved in three times its weight of concentrated sulphuric acid and heated to from
about 190 to 200 degrees Centigrade or from about 140 to 150 degrees Centigrade
for a considerable period whilst being stirred in an open vessel. By taking samples
and dissolving them in alcohol the completion of the reaction can be readily ascertained.
by observing the increasingly vivid character of the fluorescence of these solutions.
When the heating has been continued for too long a time the shade of the resulting
colouring matter is yellower and duller; the fluorescence being greener and likewise
duller, whereas the alcoholic solution of the product, when the operation has been
properly conducted, is of a pure blue-red and has a vivid yellow fluorescence...

page_text: The change that takes place consists in an intra molecular splitting off of water and
perhaps in an oxidation and is represented by the following equation.
The melt is poured into a small quantity of water, boiled and when zinc-chloride
has been employed as the condensing agent, the colouring matter is precipitated with
common salt.
When sulphuric acid is employed the greater part of the acid is neutralised with
soda or lime and after filtering the colour base is thrown down with ammonia. The
latter is then dissolved in the calculated quantity of hydrochloric acid and a small
quantity of water and the colouring matter is precipitated by the addition of Zn.—Cl₂
and Na-Cl. The colouring matter, thus obtained, being dried at 60 degrees Centi-
grade is in the form of a dark powder with a bronze lustre the watery and alcoholic
solutions of which are more or less vividly fluorescent.
These products dye animal fibre and vegetable fibre (treated with tannic acid) in
the same way as rhodamine and develope especially on silk a red exhibiting the most
splendid fluorescence.
The isolation of the leuco base as herein before described is not absolutely
necessary.
The actual coupling of the two components and the internal condensation can be
effected in one operation by proceeding as follows for example. There are taken :—
1 molecular proportion of aldehyde, and 2 molecular proportions of amido-pheno!
dissolved in the calculated quantity of concentrated hydro-chloric acid, and 3 times
the weight of the aldehyde of zinc-chloride and these are heated for about 24 hours to
a temperature of about 100 degrees Centigrade.
The materials being stirred the temperature is slowly raised to about 150 degrees
Centigrade and finally to about 200 degrees Centigrade. The splitting of the second
molecule of water with direct formation of the colouring matter then takes place.
The following may be taken as examples of this manufacture. Example A:-
About 106 parts by weight of benzaldehyde are very gradually introduced in the
course of about twelve hours into a solution (heated to 100 degrees Centigrade) of
about 27-4 parts by weight of meta-hydroxy-dimethyl-aniline and about 30 parts by
weight of zinc-chloride in about 22 parts by weight of concentrated hydrochloric acid
(of about 33 per cent. strength). After being maintained at the temperature of a
water bath for another 12 hours, and frequently stirred the yellowish brown melt is
gradually heated to about 200 degrees Centigrade. The red melt obtained by this
When
method is then subjected to further treatment as herein before described.
working with closed vessels the whole of the aldehyde may be introduced at once.

page_text: Example B-According to another method about five parts by weight of para
dimethyl-ainido-benzaldehyde and about eleven parts by weight of meta-hydroxy-
diethyl-aniline and about forty parts by weight of concentrated sulphuric acid are
heated to about 100° Centigrade for about two or three hours and then maintained at
from about 140 to 150 degrees Centigrade until a sample on being poured into a
small quantity of cold water and mixed with alcohol displays the desired colour and
fluorescence. The actual colouring matter is obtained as hereinbefore described.
There are several publications relating to processes in which multiple halogen.
derivatives of methane are allowed to act on dimethyl aniline or diethyl aniline.
Corresponding reactions take place in the employment of meta-hydroxy-dimethyl-
aniline, meta-hydroxy-diethyl-aniline, and meta-hydroxy-diphenylamine.
My foreign correspondents have discovered that good results are obtained by the
action of one molecular proportion of methylene-chloride or acetone upon two
molecular proportions of meta-hydroxy-dimethyl-aniline or meta-hydroxy-diethyl-
aniline or one molecular proportion of benzil or nitro-benzil upon four molecular
proportions of metahydroxydimethylaniline or metahydroxydiethylaniline on the
other hand, at temperatures of from about 130 to 180 degrees Centigrade. In the first
place there is formed the hydrochloric acid salt of the corresponding dihydroxylised
tetra-methyl-diamido-diphenylene-methane or its derivative in which two CH, groups
are substituted in the methylene radicle.
When these salts are slowly introduced into from 4 to 5 times the quantity of concen-
trated sulphuric acid, hydrochloric acid gas is generated and after heating for about
half an hour to from about 150 to 160 degrees Centigrade and pouring the melt into
water, red and highly fluorescent solutions of colouring matter are obtained which are
transformed into dyes in the usual manner. The new substances thus obtained appear
to resemble rhodatnine. This process may be conducted as follows:-
Example A: About 3-4 parts by weight of methylene-chloride and about 11 parts
by weight of meta-hydroxy-dimethyl-aniline are heated under pressure for about 3 or
4 hours to form about 130 to 140 degrees Centigrade and then slowly introduced into
about 60 parts by weight of concentrated sulphuric acid of about 66 degrees Beaumé
whereupon hydrochloric acid gas is given off. After heating to about 160 degrees
Centigrade for about half an hour the materials are poured into about 200 parts by
weight of cold water and precipitated by excess of soda lye.
The liquid is decanted from the resinous separated base which is then dissolved in
about 9 parts by weight of hydrochloric acid (at 33 per cent.) and 50 parts of water.
The colouring matter is then separated by means of zinc-chloride and common salt in
the form of a double salt of chloride of zinc. The precipitate being resinous at first,
solidifies in a crystalline form after about 24 hours and is dried preferably at a tempe-
rature of from about to 30 to 40 degrees Centigrade. The colouring matter thus
obtained is in the form of a green-bronze lustrous powder readily soluble in cold
water and dyes animal fibre and vegetable fibre (treated with tannic acid) of the same
shade as rhodamine.
Example B-According to another method about 10-5 parts by weight of acetone,
57 parts by weight of meta-hydroxy-diethyl-aniline and 30 parts by weight of zinc-
chloride are intimately mixed and heated to about 180 degrees Centigrade in a closed
vessel for about 13 hours. After cooling and opening the vessel the excess of
acetone is driven off by heat. The mass is then dissolved in hot and highly diluted
hydrochloric acid and the resulting base is precipitated with acetate of soda.
filtering off the resinous base it is dissolved in about 200 parts by weight of concen-
trated sulphuric acid and heated to about 160 degrees Centigrade for say half an hour.
The melt after being poured into water is further treated as in the preceding
example.
After

page_text: My foreign correspondents have also discovered that the reaction may be extended
to the treatment of aldehydes of the fatty group such as formaldehyde or acetic alde-
hyde (paraldehyde) formic acid, oxy-chloride of carbon (phosgene) benzal-chloride,
benzo-tri-chloride, the diphenyl-tri-chlorethane obtained from chloral and the diphenyl-
di-chlorethylene obtained from this chlorethane.
The condensation with alkylised meta-amido-phenol is proceeded with in either
open or closed vessels according to the nature of the materials with or without the
employment of condensing agents and generally at a high temperature between about
100 and 200 degrees Centigrade. This reaction is proportionately easier when two
halogen atoms of one molecule of one of the components act upon two hydrogen atoms
of the neucleus of two molecules of the abovementioned aromatic bases.
The reaction proceeds with difficulty and only with the aid of condensing agents
when aldehydes of the fatty group are employed one oxygen atom of the aldehyde
being caused to react upon two hydrogen atoms of the neucleus of two molecules of
the aromatic base, with the formation of one molecule of water.
On the other hand all those substances (except chloroform which reacts with more
difficulty) in whose molecules not two only but three of the hydrogen atoms are
replaced by elements or groups, capable of reacting such as a halogen, oxygen,
hydroxyl and the like, are condensed with great ease. The yield in this case is very
profitable the crude product being of remarkable purity.
These substances are benzo-trichloride, diphenyl-chlorethane, formic acid and the
like.
Whilst phosgene, benzal-chloride, unsymmetrical diphenyl-dichlorethylene afford a
satisfactory yield of colouring matter only when condensing agents are employed
such as aluminium-chloride, zinc chloride and the like; benzo-tri-chloride reacts at
from about 30 to 40 degrees Centigrade and unsymmetrical diphenyl-tri-chlor-ethane
reacts at its melting temperature forming large quantities of red colouring matter.
When meta-hydroxy-dimethylaniline is employed violent reactions readily take place
when heat is applied too quickly. Excessive heat leads to the production either of
rhodamine-like colouring matter soluble in spirit or to no transformation whatever of
the red colouring matters into useful orange yellow dyes which in solution also present
intense fluorescence. The red colouring matters obtained from diphenyl tri-chlor-
ethane and diphenyl-di-chlor-ethylene are directly soluble in spirit.
Next to the synthesis obtained with the aid of benzo-tri-chloride by far the
greatest interest is attached to those in which formic acid is employed. The capacity
of formic acid of condensing with alkylised meta-amido-phenols is due to a certain
analogy which it presents to the aldehydes.
When for example any alkylised meta-anido-phenol is heated with glycerine and
oxalic acid, both of which are preferably dehydrated beforehand and with a small
quantity of chloride of zinc, the temperature being gradually raised to from about
110 to 120 degrees Centigrade, the materials assume at first a blue colour. On
heating to a higher degree the mass becomes of a beautiful violet colour which at
from about 220 to 230 degrees Centigrade changes to a vivid red. The colouring
matter is precipitated in a state of almost chemical purity by means of common salt
and zinc-chloride from the solution of the melt in water.
The colouring matters thus obtained are of a similar nature to rhodamine. Those
obtained from meta-hydroxy-dimethyl-aniline are red with a yellow tinge, those from
meta-hydroxy-diethyl-aniline are blueish red and those from ineta-hydroxy-diphenyl-
amine are a dull violet red. The latter are insoluble in water but are readily soluble
in spirit.
The following is given as an example :-
Example A. About 7 parts by weight of meta-hydroxy-dimethyl-aniline are
dissolved in about 5.6 parts by weight of hydro-chloric acid of 33 per cent. strength.
The water is evaporated and the materials are then heated in a closed vessel to from

page_text: about 170 to 180 degrees Centigrade for say 8 hours with about 1.2 parts by weight
of paraldehyde and 40 parts by weight of zinc-chloride.
After cooling the contents of the vessel are boiled down with a small quantity of
water, slightly acidulated with hydrochloric acid allowed to cool and the chloride of
zinc and the mother liquor containing a quantity of unchanged meta-hydroxy-
dimethyl-aniline is separated from the colouring matter by filtration.
The colouring matter is dissolved in hot water and precipitated with a small quantity
of zinc-chloride and common salt after filtering.
Example B. According to another example about 66 parts by weight of meta-
hydroxy-diethyl-aniline are carefully stirred in about 1.5 parts by weight by benzo-
tri-chloride and slowly heated to from about 30 to 40 degrees Centigrade. When the
melt has assumed a strong red colour about 24 parts by weight of benzo-tri-chloride
are added care being taken that the heat resulting from the reaction is not allowed to
exceed about 60 degrees Centigrade for about 2 hours after which it is dissolved in
hot water and the colouring matter is precipitated with zinc-chloride and common salt.
Example C. According to another example; into a mixture of about 6.2 parts by
weight of unsymmetrical diphenyl-dichlor-ethylene and about 7 parts by weight of
meta-hydroxy-dimethyl-aniline there is very gradually introduced (whilst stirring)
about two parts by weight of dehydrated aluminium chloride. The melt is dissolved
in spirit and the colouring matter soluble in spirit is precipitated with water.
Example D. According to another example a mixture composed of about eleven
parts by weight of meta-hydroxy-diethyl-aniline about nine parts by weight of
dehydrated oxalic acid about 5 parts by weight of dehydrated glycerine and about
6 parts by weight of zinc-chloride, is gradually heated to from about 80 to 90 degrees
Centigrade. When the violent evolution of carbonic acid ceases, the materials are
slowly heated for a time in an open vessel to from about 110 to 120 degrees Centigrade
after which the temperature is slowly raised (whilst stirring) to from about 220 to
230 degrees Centigrade. After cooling the melt is poured into hot water acidulated
with hydrochloric acid and salted out with common salt.
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 for manufacturing leuco-bases of the triphenyl methan series
(Part I of the description) consisting in melting together benzaldehyde or nitro-
benzaldehydes, amido-benzaldehydes, alkylamido-benzaldehydes, hydroxybenzalde-
hydes, chlor-benzaldehydes, with meta-amidophenol, the alkylised derivatives thereof
and hydroxydiphenylamine or its salts in the presence of dehydrating agents.
Second. The process for manufacturing new red dyestuffs, consisting in heating
the leuco bases claimed by the preceding claiming clause with dehydrating agents.
Third. The process for manufacturing new red basic colouring matters (Part II of
the description) consisting in heating methylene-chloride-bromide or iodide, acetone
or chloroforin together with two molecular proportions or benzil, nitro-benzils with
four molecular proportions of the alkylized meta-amido-phenols or its salts with or
without the employment of a condensing agent.
Fourth. The process for manufacturing new red basic colouring matters (Part III
of the description) consisting in treating dialkyl-meta-amidophenols under pressure
with chloride of carbon (phosgene) at temperatures from about 180 degrees Centi-
grade and treating the resulting dihydroxy-tetra alkyldiamido-benzophenones with
dehydrating agents.
Fifth. The process for manufacturing new red basic colouring matters (Part III of
the description) which consists in causing-
(a) Formaldehyde-acetaldehyde (paraldehyde) unsymmetrical diphenyltrichlor-
ethane or unsymmetrical diphenyldichlorethylene to act upon meta-amido-
phenol, alkylized in the NH, group or its salts at a temperature of from about
150 to 180 degrees Centigrade with or without the employment of condensing
agents and the like, or

page_text: (b) Benzalchloride, benzotrichloride to act upon meta-amido-phenol-alkylized
in the NH, group or its salts at or under 60 degrees Centigrade with, or
without, the employment of condensing agents, or
(c) Free formic acid or a mixture of glycerine and oxalic acid to act upon
meta-amido-phenol alkylized in the NH, group or its salts with, or without, the
employment of condensing agents.
Sixth. As new articles of manufacture the new products hereinbefore described.
Dated this 24th day of March 1890.