IMPROVEMENTS IN OBTAINING COLOURING MATTERS SUITABLE FOR DYEING AND PRINTING
Year: 1880

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CARL RUMPFF,
of the Firm of Friedrich Bayer and Company, of Barmen, Rhenish Prussia,
in the Empire of Germany, Chemist, send greeting:-
WHEREAS Her most Gracious Majesty Queen Victoria, by Her Letters Patent
under the Great Seal of Great Britain & Ireland, bearing date the Twenty
fourth day of January, One thousand eight hundred and eighty, in the forty
third year of Her reign, and sealed as of the said Twenty fourth day of
January, One thousand eight hundred and eighty, Number 324, did for Herself,
and Her heirs and successors, grant unto Joseph Anthony Dixon, of 175, West
George Street, Glasgow, in the County of Lanark, North Britain, Solicitor, his.
executors, administrators, and assigns, Her especial licence, full power, sole privilege,
and authority, that he, the said Joseph Anthony Dixon, his executors, administrators,
and assigns, and every of them, by himself or themselves, or by his or their deputy
or deputies, servants, or agents, or such others as he, the said Joseph Anthony'
Dixon, bis executors, administrators, or assigns, should at any time agree with,
and no others from time to time, and at all times thereafter during the term of
years therein expressed, should lawfully make, use, exercise, and vend within the
United Kingdom of Great Britain and Ireland, the Channel Islands, and the Isle of
Man," an Invention of IMPROVEMENTS IN OBTAINING COLOURING MATTERS
SUITABLE FOR DYEING AND PRINTING," communicated to the said Joseph Anthony
Dixon from abroad by me, the said Carl Rumpff and Dr. William Conrad,
of Würtzburg, the Empire of Germany, Chemist.
"
•
And whereas, by indenture made the Twenty sixth day of April, One thousand
eight hundred and eighty, between the said Joseph Anthony Dixon of the first.
part, me, the said Carl Rumpff, of the second part, and the said Dr. William
Conrad of the third part, which was registered in the Great Seal Patent
Office, on the Fifth day of May, One thousand eight hundred and eighty,.
the said. Joseph Anthony Dixon, with the consent and concurrence of the said
Dr. William Conrad, did assign and transfer unto me, the said Carl Rumpff, my
executors and assigns, the said Letters Patent, together with the said Invention
itself, and all privileges and authorities by the said Letters Patent granted;
and the exclusive use and benefit of the said Invention, within the said
:

page_text: United Kingdom, Channel Islands, and Isle of Man, and all rights, powers,
authorities, privileges, advantages, profits, emoluments, and benefits to the
said Invention, Letters Patent, and premises, in anywise appertaining so far as
concerns the use, exercise, and enjoyment of the said Invention, within the said
United Kingdom, Channel Islands, and Isle of Man, or otherwise, under and by
virtue of the said Letters Patent, so far as he, the said Joseph Anthony Dixon, had
right or title thereto or interest therein, and all the right, title, and interest
whatsoever of the said Joseph Anthony Dixon, to and in respect of the said
Invention, Letters Patent, and premises, and all right, title, claim, action, and
demand competent to him for all royalties due or to become due for the use of said
Invention, by and for all damages for infringement of said Letters Patent, exigible
from any person or persons in time past or to come, and all rights of action founded
on any infringement or other matter or thing which is or was competent to him in
connection with the said Letters Patent :
And whereas, in pursuance and performance of a condition in the said Letters
Patent contained; the said Joseph Anthony Dixon did, within six calendar months
next after the date of the said Letters Patent, cause a Specification in writing, under
his hand and seal, particularly describing the nature of the said Invention, and in
what manner the same was to be performed, to be duly filed in the Great Seal
Patent Office :
And whereas, since the filing of the said Specification I have been advised that
the statement, hereinafter particularly mentioned, contained in the said Specification
to the effect that certain sulpho acids when subjected to Lauth's reaction will
yield blue colouring matters suitable for dyeing and printing, is too wide, and
includes other bodies than were meant to be included therein, and I am, for the
purpose of obviating all doubts respecting the said statement, desirous of dis-
claiming such part of the said Specification to the extent to which it includes other
bodies than were meant to be included therein, and of amending the said Speci-
fication in manner hereinafter mentioned.
And whereas, I have discovered since the filing of the said Specification that
certain words and figures, hereinafter particularly mentioned, have been erroneously
transcribed or copied in the said Specification, and I am desirous of striking out
the said words and figures, and substituting for the said words the correct words
which were intended to have been written instead of those standing in the said
Specification.
«<
"
NOW KNOW YE, that I, the said Carl Rumpff, by and with the leave of Her
Majesty's Solicitor General, do hereby, for the reasons aforesaid and for effecting
the objects aforesaid, add to the said Specification after the word "acids," occurring.
on the thirty third line of page 3 of the said print of the said Specification,
printed by the Queen's printers, and published at the Great Seal Patent Oilice, the
following words in brackets, videlicet, "[restricting them however to the sulpho
"acids of the reduced bases obtained from the said nitroso derivatives of such
tertiary aromatic monamines as consist of aniline or other amido compound of
"an aromatic hydrocarbon with its amido hydrogens substituted by two alkyls, or
by an alkyl and a phenyl, or other like aromatic hydrocarbon radicle]." I also
add to the said Specification after the word "Patent," occurring on the nineteenth
line of page 5 of the said print of the said Specification, the words, "the sulpho
"acids to be used for the production of the colouring matter being restricted as
" above mentioned." I also add to the said Specification after the word "described,"
occurring on the twenty second line of the said page 5 of the said print of the
said Specification, the words "as suitable.” And I also add after the word "acids,"
occurring on the twenty ninth line of the said page 5 of the said print of the
aaid Specification, the words, "such as are indicated as being suitable." And,
further, I strike out and omit the figure "3" preceding the formula (NH), S, O,
in both the places in which it occurs, at the commencement of line 12 of
page 3, and after the word "thiosulphate" in line 21 of page 4 of the said

page_text: print. And, further, I strike out in both the places in which it occurs the
word "sulphite," which occurs twice in the thirteenth line of page 4 of the said
print, and in each case I substitute the word "sulphide in place thereof. And
in order that it may be clearly understood what is the Invention which I now
consider to be secured by the hereinbefore in part recited Letters Patent, I
shall proceed to repeat (omitting preamble and testing clause) the said Specification
as proposed to be amended by this present Disclaimer and Memorandum of
Alteration, as follows:-
The persons from whom I have received the communication of the Invention
hereinafter described made the observation that when sulphite of ammonia
(NH), SO,, or the hyposulphite (otherwise called the thiosulphate) of ammonia
(NH), S, O, is caused to react on nitroso-dimethylanilin the nitroso group is
reduced, and at the same time a sulphonic acid of the reduced base is produced. The
object of this Invention is, besides producing the said sulphonic acid of the said
reduced base in manner mentioned, to use the said sulphonic acid for the purpose
of producing a blue colouring matter therefrom by applying to the same (instead of
to para amido dimethylanilin) the reaction first indicated by Charles Lauth
(Berichte der Deutschen Chemischen Gesellschaft, 1876, page 1035), for the
production of a violet colouring matter from para diamido benzole or its
homologues, that is to say, treatment with sulphuretted hydrogen and oxydising
agents.
Nitroso-dimethylanilin may be prepared in a way well known to chemists by
acting on a solution of dimethylanilin in hydrochloric acid and water with nitrite
of soda or free nitrous acid, and then isolating the nitroso-dimethylanilin from the
hydrochlorate of nitroso-dimethylanilin so produced, and the nitroso derivatives of
the other tertiary aromatic monamines may be obtained by an analogous reaction.
The preparation of nitroso-dimethylanilin, or any other of the said nitroso
derivatives, is not claimed as forming any part of this Invention; but by treating
the nitroso derivatives of the tertiary aromatic monamines generally with sulphite
or hyposulphite of ammonia the nitroso group is reduced, and a sulphonic acid of
the reduced base may be obtained in a manner perfectly analogous to that by
which the sulphonic acid of the reduced base is obtained from nitroso dimethyl-
anilin, and these sulpho acids (restricting them however to the sulpho acids of the
reduced bases obtained from the said nitroso derivatives of such tertiary aromatic
monamines as consist of aniline or other amido compound of an aromatic hydro-
carbon, with its amido hydrogens substituted by two alkyls, or by an alkyl and a
phenyl, or other like aromatic hydrocarbon radicle) when subjected to Lauth's
reaction will also yield blue colouring matters suitable for dyeing and printing.
Thus the same or nearly the same results obtained by the treatment in manner
hereinafter described of nitroso-dimethylanilin may be obtained by using instead
thereof the nitroso derivatives of the compounds of two methyls and toluidine,
or of two methyls and any other homologue of aniline, or by using the nitroso
derivatives of the compounds of aniline, toluidine, and their homologues with
two ethyls or two other alkyl radicles, whether such radicles be the same as
or different from each other, as for example, the nitroso derivatives of diethylanilin,
of methylethylanilin, of dimethyl- or diethyl-orthotoluidine, and of methyl- or ethyl-
diphenylamin. There is however no advantage to be obtained by using any of
these nitroso compounds (which I regard for the purposes of the present Invention
as merely chemical equivalents of the nitroso derivatives of dimethylanilin) in place
and as I recommend the use of nitroso dimethylanilin
A
of nitroso dimethylanilin, by preference, I merely include the said other nitroso
derivatives for the purpose of preventing evasion of the said Patent by means
thereof, and I shall in the following exposition of this Invention assume that I
work with nitroso-dimethylanilin.
In order to produce the sulpho acid derivable by the reaction above mentioned
from nitroso dimethylanilin, sulphite of ammonia in the form of the dry salt, or the
concentrated watery solution, is allowed to act on a boiling alcoholic solution of

page_text: the nitroso-dimethylanilin. In this way I succeed in getting the reaction to
proceed smoothly and rapidly, and I avoid the employment of large quantities
either of liquors, or of sulphuretted hydrogen as reducing agent. The sulpho acid
of the reduced base, which is the product of this reaction, is obtained in the form
of an ammonia salt of the said sulpho acid, which sulpho acid on heating with acids
splits up into sulphuric acid and amido dimethylanilin. It is not however
necessary that the sulphonic acid should be isolated from the ammonia base before
being subjected to the treatment with sulphuretted hydrogen, as hereinafter
mentioned. The quantities of sulphuretted hydrogen absolutely necessary for the
formation of the blue colouring matter are small, and may be produced directly in
an acid solution of the sulphonic acid, or of its salt, contained in an open vessel by
adding sulphide of sodium to the solution. Any other convenient sulphide may be
used which will give sulphuretted hydrogen in an acid liquor, or the sulphuretted
hydrogen may be generated by any of the well known methods in a separate
vessel, and conveyed into the acidulated solution of the sulpho acid or its salt. For
oxidizing agent, ferric chloride may be employed with great advantage, but other
oxidizing agents which are well known to chemists may be substituted for the
ferric chloride, as bichromate of potash and an acid. The sulphite of ammonia may,
as already stated, be replaced by the hydrosulphurous acid salt, that is to say, by
ammonium thio-sulphate (NH4)2S, O
In order to convert into blue colouring matter the sulphonic acid of the reduced
base obtained by the action of sulphite or hyposulphite of ammonia on a nitroso
derivative of a tertiary aromatic monamin, such as is hereinbefore described, or on
the ammonia salt of such a sulpho acid, the same may be treated either (first) with
sulphuretted hydrogen and then with the oxidizing agent, or (second) the order of
applying these re-agents may be reversed, but not with advantage.
I now proceed to give a description of the process as applied to nitroso-
dimethylanilin, and I observe that the quantitative proportions of materials herein-
after stated yield a satisfactory result, but that they are susceptible of variation
within limits of considerable width.
First. For the preparation of the sulpho acid product of the reaction of sulphite
of ammonia on nitroso dimethylanilin I take ten kilogrammes of nitroso dimethyl-
anilin, which are dissolved in fifty kilogrammes of alcohol; into the boiling solution
there are allowed to flow gradually fifty kilogrammes of a watery solution of
sulphite of ammonia (sp. gr. 1.24, contents in (NH), SO,, about 38.6 per cent.
The mixture colours itself brown, and assumes as the boiling is continued an acid
which is changed by the addition of carbonate of ammonia into the basic reaction. The reaction
reaction,
of the sulphite on the nitroso-dimethylanilin is complete in about an
hour. The alcohol is then distilled off; the watery solution remaining behind
contains, besides much sulphate and a little sulphite of ammonia, the ammonia salt
of a sulpho acid, which on beating with acids splits up into sulphuric acid and
amido dimethylanilin.
Second. The object of the next part of the process is the conversion of the
sulphonic acid so obtained or its ammonia salt into the blue colouring matter. For
the preparation of the blue colouring matter it is not necessary, as I have before
mentioned, to isolate the sulphonic acid from the ammonia salt thereof. The watery
solution of the said ammonia salt is mixed with 80 kilogrammes of hydrochloric
acid.
After the sulphurous acid which proceeds from the sulphite of ammonia present
has escaped, the strongly acid solution is diluted with about seven times its volume
of water, and thereafter (the liquor being kept heated) sulphide of sodium (about
6 kilogrammes) is introduced into it until an excess of sulphuretted hydrogen
makes itself manifest by the smell.
Into the cooled colourless sulphuretted hydrogen holding solution there is then
allowed to flow for the purpose of producing the blue colouring matter a solution
of 26 kilogrammes of ferric chloride in 200 litres of water.
The colouring matter forms at once, and it is afterwards precipitated from the

page_text: watery solution in the form (by preference) of the chloride of zinc compound by
saturating the solution with common salt, and precipitating with chloride of zinc
in aqueous solution.
The process as applied to the nitroso derivatives of the other tertiary aromatic
monamines is substantially the same as or similar to the process as applied to the
nitroso dimethylanilin.
Having thus described the nature of the said Invention, and the manner in
which the same is to be performed, I wish to observe that I do not limit myself to
the precise quantities and proportions mentioned in the preceding description of
the process, and that other oxidants and other sources of sulphuretted hydrogen
may be substituted for those herein before mentioned, but what I believe to be new
in the said Invention herein before described, and what I claim as secured to me by
said Letters Patent, the sulpho acids to be used for the production of the colouring
matter being restricted as above mentioned, is,-
First. The obtaining of colouring matter or matters by preparing from nitroso-
dimethylanilin or from the nitroso derivative of any of the tertiary aromatic
monamines hereinbefore described, as suitable by the action of sulphite or hypo-
sulphite (thiosulphate) of ammonia thereon in manner herein before described, the
sulpho acid of the corresponding reduced base or its ammonia salt, and by then
subjecting such sulpho acid or its said salt to the successive action in manner
herein before described of sulphuretted hydrogen, and of an oxydizing agent such
as ferric chloride.
Second. And, separatim, the preparation (as a source from which colouring matter
or matters may be obtained) of sulpho acids, such as are indicated as being suitable,
of the reduced bases from the nitroso derivatives of the tertiary aromatic mona-
mines herein before described by acting on the said nitroso derivatives with
sulphite or hyposulphite (thiosulphite) of ammonia in manner herein before
described.
In witness whereof, I, the said Carl Rumpff, have hereunto set my hand and
seal, this Twentyfifth day of February, in the year of our Lord One
thousand eight hundred and eighty one.
Signed and sealed in the
presence of
JAMES ANSTEY WILD,
Solicitor,
10, Ironmonger Lane,
E.C.
To the Commissioners of Patents for Inventions.
I hereby grant my fiat, giving leave to the witbin-named Carl Rumpff, to file in
the Great Seal Patent Office, with the Specification to which the same relates, the
above written Disclaimer and Memorandum of Alteration.

page_text: LETTERS PATENT to Joseph Anthony Dixon, of 175, West George Street,
Glasgow, in the County of Lanark, North Britain, Solicitor, for an Invention
of "IMPROVEMENTS IN OBTAINING COLOURING MATTERS SUITABLE FOR DYEING
AND PRINTING." A communication from abroad by Carl Rumpff, of Barmen,
Rhenish Prussia, in the Empire of Germany, Chemist, and Doctor William
Conrad, of Würtzburg, in the Empire of Germany, Chemist.
PROVISIONAL SPECIFICATION left by the said Joseph Anthony Dixon at
the Office of the Commissioners of Patents on the 24th January 1880.
JOSEPH ANTHONY DIXON, of 175, West George Street, Glasgow, in the County
of Lanark, North Britain, Solicitor. "IMPROVEMENTS IN OBTAINING COLOURING
MATTERS SUITABLE FOR DYEING AND PRINTING." [A communication from abroad
by Carl Rumpff, of Barmen, Rhenish Prussia, in the Empire of Germany, Chemist,
and Doctor William Conrad, of Würtzburg, in the Empire of Germany, Chemist.]
The said persons from whom I received the communication have made the
observation that in the reaction of sulphite of ammonia on nitrosodimethylanilin
a sulphonic acid of the reduced base is produced, and they propose to use this
product instead of the para-amido-dimethylanilin for the preparation of a blue
colouring matter by subjecting the same to the reaction, first published by Charles
Lauth (Berichte der Deutschen Chemischen Gesellschaft, 1876, page 1035), for the
production from para-diamido-benzol of a violet colouring matter, that is to say,
to treatment with sulphuretted hydrogen and oxidizing agents.
The sulphite of ammonia in the form of the dry salt or in concentrated watery
tion is allowed to act on a boiling alcoholic solution of nitroso-dimethylanilin.
way the reaction proceeds smoothly and quickly, and the employment of
quantities either of liquors or of sulphuretted hydrogen as reducing agent is
1.
quantities of sulphuretted hydrogen absolutely necessary for the formation
of the blue colouring matter are small, and are produced directly in the acid solution
of the sulphonic acid contained in an open vessel upon addition of sulphide of
sodium thereto.
As oxidizing agent the the ferric chlorid may be applied with advantage.

page_text: The sulphite of ammonia may, according to the experience of the said persons
from whom I received this communication, be replaced by the hyposulphurous acid
Balt
Besides the sulpho acid which may, as hereinbefore mentioned, be prepared from
nitroso di metbylanilin, the sulpho acids prepared in an analogous manner from
the nitroso derivatives of di-ethyl-anilin, of methyl-ethyl-anilin, of di-methyl- or
di-ethyl-ortho-toluidine, and of methyl- or ethyl-diphenylamin, and generally from
the nitroso derivatives of the tertiary aromatic monamines, may be used for the
preparation of clouring matters.
I give in the following paragraphs a description of the process. The quantitative
proportions stated yield a satisfactory result, but are susceptible of variation.
First. Preparation of the product of the reaction of sulphite of ammonia on
nitrosodimethylanilin.
10 kilogrammes of nitroso-dimethylanilin are dissolved in
50 kilogrammes of alcohol. Into the boiling solution there are allowed to
flow gradually
50 kilogrammes of a watery solution of sulphite of ammonia (sp. gr. 1.24,
contents in (NH), SO, about 38-6 per cent).
The mixture colours itself brown, and assumes as the boiling is continued an
acid reaction, which is arrested by the addition of carbonate of ammonia. The
reaction is after the lapse of an hour complete. The alcohol is distilled off; the
watery solution remaining behind contains besides much sulphate, a little sulphite
of ammonia, and the ammonia salt of a sulpho acid, which on heating with acids is
split up into sulphuric acid and amidodimethylanilin.
Second. Conversion of the sulphonic acid into the blue colouring matter.
For the preparation of the blue colouring matter it is not necessary to isolate the
sulphonic acid. The watery solution of the ammonia salt is mixed with 80 kilo-
grammes of hydrochloric acid.
After the sulphurous acid which proceeds from the sulphite of ammonia present
has escaped the strongly acid solution is diluted with about seven times its volume
of water, and thereafter (the liquor being heated) sulphide of sodium (about 6
kilogrammes) is introduced into it until an excess of sulphuretted hydrogen makes
itself manifest by the smell.
Into the cooled, colourless, sulphuretted-hydrogen-holding solution there is
allowed to flow, for the purpose of producing the blue colouring matter, a
solution of
26 kilogrammes of ferric chloride in

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Anthony Dixon in the Great Seal Patent Office on the 8th
June 1880.
JOSEPH ANTHONY DIXON, of 175, West George Street, Glasgow, in the County
of Lanark, North Britain, Solicitor. "IMPROVEMENTS IN OBTAINING COLOURING
MATTERS SUITABLE FOR DYEING AND PRINTING." A communication from abroad
by Carl Rumpff, of Barmen, Rhenish Prussia, in the Empire of Germany, Chemist,
and Doctor William Conrad, of Würtzburg, in the Empire of Germany, Chemist.
The persons from whom I have received the communication of the Invention,
hereinafter described, made the observation that when sulphite of ammonia
(NH), SO, or the hyposulphite (otherwise called the thiosulphate) of ammonia
3 (NH), Š₂O₂, is caused to react on nitroso-dimethylanilin, the nitroso-group is
reduced, and at the same time a sulphonic acid of the reduced base is produced.
The object of this Invention is, besides producing the said sulphonic acid of the
said reduced base in manner mentioned, to use the said sulphonic acid for the
purpose of producing a blue colouring matter therefrom, by applying to the same
(instead of to para amido dimethylanilin) the reaction first indicated by Charles
Lauth (Berichte der Deutschen Chemischen Gesellschaft, 1876, page 1035) for the
production of a violet colouring matter from para diamido benzole or its homo-
logues, that is to say, treatment with sulphuretted hydrogen and oxydizing
agents.
Nitroso-dimethylanilin may be prepared in a way well known to chemists by
acting on a solution of dimethylanilin in hydrochloric acid and water with nitrite
of soda or free nitrous acid, and then isolating the nitroso-dimethylanilin from the
hydrochlorate of nitroso-dimethylanilin so produced. And the nitroso derivatives
of the other tertiary aromatic monamines may be obtained by an analogous
reaction. The preparation of nitroso-dimethylanilin or any other of the said nitroso
derivatives is not claimed as forming any part of this Invention; but by treating
the nitroso derivatives of the tertiary aromatic monamines generally with sulphite
or hyposulphite of ammonia the nitroso group is reduced, and a sulphonic acid of
the reduced base may be obtained in a manner perfectly analogous to that by which
the sulphonic acid of the reduced base is obtained from nitroso dimethylanilin, and
these sulpho acids when subjected to Lauth's reaction will also yield blue colouring
matters suitable for dyeing and printing. Thus the same or nearly the same results
obtained by the treatment in manner hereinafter described of nitroso dimethyl-
aniline may be obtained by using instead thereof the nitroso derivatives of the
compounds of two methyls and toluidine, or of two methyls and any other homo-
logue of aniline, or by using the nitroso derivatives of the compounds of aniline,
toluidine, and their homologues, with two ethyls or two other alkyl radicles,
whether such radicles be the same as or different from each other, as, for example,
the nitroso derivatives of diethylanilin, of methylethylanilin, of dimethyl- or
diethyl-ortho-toluidine, and of methyl- or ethyl-diphenylamin. There is however
no advantage to be obtained by using any of these nitroso compounds (which I
regard for the purposes of the present Invention as merely chemical equivalents of
the nitroso derivatives of dimethylanilin) in place of nitrosodimethylanilin. And
as I recommend the use of nitroso-dimethylanilin by preference, I merely include
the said other nitroso derivatives for the purpose of preventing evasion of the said
Patent by means thereof, and I shall in the following exposition of this Invention
assume that I work with nitrosodimethylanilin.
In order to produce the sulpho acid derivable by the reaction above mentioned
from nitrosodimethylanilin, sulphide of ammonia, in the form of the dry

page_text: salt or in concentrated watery solution, is allowed to act on a boiling alcoholic
solution of the nitroso-dimethylanilin. In this way I succeed in getting the reaction
to proceed smoothly and rapidly, and I avoid the employment of large quantities
either of liquors or of sulphuretted hydrogen as reducing agent. The sulpho acid
of the reduced base, which is the product of this reaction is obtained in the form of
an ammonia salt of the said sulpho acid, which sulpho acid on heating with acids
splits up into sulphuric acid and amido dimethylanilin. It is not however, necessary
that the sulphonic acid should be isolated from the ammonia base before being
subjected to the treatment with sulphuretted hydrogen, as hereinafter mentioned.
The quantities of sulphuretted hydrogen absolutely necessary for the formation of
the blue colouring matter are small, and may be produced directly in an acid
solution of the sulphonic acid, or of its salt, contained in an open vessel, by adding
sulphite of sodium to the solution. Any other convenient sulphite may be used
which will give sulphuretted hydrogen in an acid liquor, or the sulphuretted
hydrogen may be generated by any of the well known methods in a separate vessel,
and conveyed into the acidulated solution of the sulpho acid or its salt. For
oxydizing agent, ferric chloride may be employed with great advantage, but other
oxydizing agents which are well known to chemists, may be substituted for the
ferric chloride, as bichromate of potash and an acid. The sulphide of ammonia may,
as already stated, be replaced by the hyposulphurous acid salt, that is to say, by
ammonium thiosulphate 3 (NH), S₂O¸
In order to convert into blue colouring matter the sulphonic acid of the reduced
base, obtained by the action of sulphite or byposulphite of ammonia on a nitroso
derivative of a tertiary aromatic monamin, such as is hereinbefore described, or on
the ammonia salt of such a sulpho acid, the same may be treated either (first) with
sulphuretted hydrogen and then with the oxydizing agent, or (second) the order of
applying these reagents may be reversed, but not with advantage.
I now proceed to give a description of the process as applied to nitroso-
dimethylanilin, and I observe that the quantitative proportions of materials herein-
after stated yield a satisfactory result, but that they are susceptible of variation
within limits of considerable width.
First. For the preparation of the sulpho acid product of the reaction of sulphite
of ammonia on nitrosodimethylanilin, I take,-
10 kilogrammes of nitrosodimethylanilin which are dissolved in
50 kilogrammes of alcohol. Into the boiling solution there are allowed to
flow gradually
50 kilogrammes of a watery solution of sulphite of ammonia, (sp. gr. 1·24,
contents in (NH), SO, about 38.6 per cent.)
The mixture colours itself brown, and assumes, as the boiling is continued, an
acid reaction, which is changed by the addition of carbonate of ammonia into the
basic reaction. The reaction of the sulphite on the nitrosodimethylanilin is complete
in about an hour. The alcohol is then distilled off; the watery solution remaining
behind contains, besides much sulphate and a little sulphite of ammonia, the
ammonia salt of a sulpho acid which, on heating with acids, splits up into sulphuric
acid and amidodimethylanilin.
Second. The object of the next part of the process is the conversion of the
sulphonic acid so obtained or its ammonia salt into the blue colouring matter.
For the preparation of the blue colouring matter, it is not necessary, as I have
before mentioned, to isolate the sulphonic acid from the ammonia salt thereof. The
watery solution of the said ammonia salt is mixed with 80 kilogrammes of
hydrochloric acid.
After the sulphurous acid which proceeds from the sulphite of ammonia present,
has escaped, the strongly acid solution is diluted with about seven times its volume
of water, and thereafter (the liquor being kept heated) sulphide of sodium (about 6
kilogrammes) is introduced into it until an excess of sulphuretted hydrogen
makes itself manifest by the smell.

page_text: Into the cooled, colourless, sulphuretted-hydrogen-holding solution there is
then allowed to flow for the purpose of producing the blue colouring matter a
solution of
26 kilogrammes of ferric chloride in
200 litres of water.
The colouring matter forms at once, and it is afterwards precipitated from the
watery solution in the form (by preference) of the chloride of zinc compound, by
saturating the solution with common salt and precipitating with chloride of zinc, in
aqueous solution.
The process as applied to the nitroso derivatives of the other tertiary aromatic
monamines is substantially the same, as or similar to the process as applied to the
nitroso dimethylanilin.
Having thus described the nature of the said Invention, and the manner in
which the same is to be performed, I wish to observe that I do not limit myself to
the precise quantities and proportions mentioned in the preceding description of the
process, and that other oxidants and other sources of sulphuretted hydrogen may
be substituted for those herein before mentioned, but what I believe to be new in
the said Invention bereinbefore described, and what I claim as secured to me by
said Letters Patent is,-
First. The obtaining of colouring matter or matters by preparing from nitroso-
dimethylanilin, or from the nitroso derivative of any of the tertiary aromatic
monamines herein before described, by the action of sulphite or hyposulphite
(thiosulphate) of ammonia thereon, in manner herein before described, the sulpho
acid of the corresponding reduced base or its ammonia salt, and by then subjecting
such sulpho acid or its said salt to the successive action, in manner herein before
described, of sulphuretted hydrogen and of an oxydizing agent, such as ferric
chloride.
Second. And, separation the preparation (as a source from which colouring matter
or matters may be obtained) of sulpho acids of the reduced bases from the nitroso
derivaties of the tertiary aromatic monamines, hereinbefore described, by acting on
the said nitroso derivatives with sulphite or hyposulphite (thiosulphate) of ammonia,
in manner herein before described.
In witness whereof, I, the said Joseph Anthony Dixon, have hereunto set
my hand and seal, this Twenty fourth day of May, in the year of our Lord
One thousand eight hundred and eighty.
JOSEPH ANTHONY DIXON. (LS)