A NEW MANUFACTURE OF BLUE COLORING MATTERS PRO
Year: 1882

page_text: LETTERS PATENT to Raphael Meldola, Chemist to the Firm of Brooke Simpson
and Spiller, of the Atlas Works, Hackney Wick in the County of Middlesex
LETTERS PATENT to Raphael Meldola, Chemist to the Firm of Brooke Simpson
and Spiller, of the Atlas Works, Hackney Wick in the County of Middlesex
for an invention of "A NEW MANUFACTURE OF BLUE COLORING MATTERS
PROVISIONAL SPECIFICATION left by the said Raphael Meldola at the
Office of the Commissioners of Patents on the 24th May 1882.
RAPHAEL MELDOLA, Chemist to the Firm of Brooke, Simpson and Spiller, of the
Atlas Works, Hackney Wick in the County of Middlesex "A NEW MANUFACTURE
OF BLUE COLORING MATTERS "
My present invention relates to a new method for manufacturing blue coloring
matters by the action of suitable oxidising agents upon the products of the
reduction of certain diazo-colors derived from the amido-sulphonic acids of
napthalene and tertiary monamines (such as dimethylaniline, diethylaniline,
methyldiphenylamine, &c.) in the presence of sulphuretted hydrogen in accordance
with the well-known reaction discovered by Lauth.
In carrying out this invention I take one of the isomeric amidonapthalene-
sulphonic acids known to chemists and convert it into a diazo-sulphonic acid by
acting upon it with the necessary quantity of nitrous acid or of a nitrite in the
presence of a mineral acid. This diazosulphonic acid is then allowed to act upon
dimethylaniline, diethylaniline, or other tertiary monamines so as to produce
diazo-colours of which the formulæ are:-
C₁0 Hε. HSO. N
CH>
=
N. CH. C,H,
N
C₁H₁₂
&c.
C10 H. HSO,. N = N. CH. CH₁
N
These diazo-colors are all orange dye-stuffs, and by preference I use the
compounds derived from those amido-sulphonic acids of napthalene containing the
amidogen in the "beta" position, as is well understood by chemists, owing to
the greater facility with which such amido-sulphonic acids form the diazo-colors
above mentioned.
The following is the process for carrying out the manufacture of the blue
coloring matter according to my invention:-
First operation. Ten parts by weight of the amidonapthelene-sulphonic acid
prepared either by the action of sulphuric acid upon beta-napthylamine, or by

page_text: reducing the nitro-sulphonic acids obtained by the action of nitric acid upon the beta-
napthalene-sulphonic acid, as discovered by Clève, are suspended in cold water
acidulated with muriatic acid and a solution of nitrate of soda is gradually added
in such quantity as shall contain 3-09 parts by weight of pure nitrite. The
solutions after being mixed are kept well cooled and are allowed to stand for
some hours so as to form the diazo-sulphonic acid or mixture of isomeric acids as
mentioned. When the diazotizing operation is complete, which is the case in
about two hours, there is added a solution containing 54 parts by weight of
dimethylaniline or 67 parts of diethylaniline dissolved in the necessary quantity
of muriatic acid, and after standing for some hours the diazo-color begins to
separate and is completely thrown out by the addition of ammonia to the mixed
solutions
Second operation. The ammoniacal solution containing the ammonium salt of
the diazo-color in suspension is mixed with a solution of yellow sulphide of
ammonium and the mixture kept at a temperature of 80° to 90° Centigrade till
the diazo-color is completely reduced, as is ascertained by the mixture becoming
colorless. The reduction is much hastened by the addition of a small quantity of
zine dust. The solution is now rapidly cooled and made acid by means of muriatic
acid, and the sulphur and amido-napthalene-sulphonic acid thus precipitated is
removed by filtration. The solution is then oxidised by ferric chloride or other
suitable oxidising substances till the smell of sulphuretted hydrogen is destroyed,
when the coloring matter at once forms and is precipitated by the addition of
chloride. of zinc and common salt in the usual way. The amido-napthalene-
sulphonic acid is freed from sulphur by dissolving it in a weak solution of an
alkali, filtering and precipitating by muriatic acid, and the acid thus recovered
can be again used for the manufacture of the blue dye-stuff. The coloring matter
precipitated in the manner above described is collected on filters in order to
remove a red coloring matter which remains in the solution and is purified by
dissolving in hot water, filtering and again precipitating by zinc chloride and
common salt.
When collected it can be dried and is then ready for use, or it can
be employed in the form of a paste. It dyes silk and wool from a neutral or
ammoniacal bath of a fine blue shade and it can be used also for cotton with or
.without a mordant according to the shade required.
The advantage of the method herein described consists in the facility with
which the diazo colors above mentioned can be reduced by means of the sulphides
of ammonium or sodium, and the ease with which the amido-napthalene-sulphonic
acids employed can be recovered for use. I wish it further to be understood that
the operations above described may be varied in their order of application and I by
no means bind myself to the precise order as above set forth.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Raphael Meldola in the Great Seal Patent Office on the
8th November 1882.
RAPHAEL MELDOLA, Chemist to the Firm of Brooke, Simpson and Spiller, of the
Atlas Works, Hackney Wick in the County of Middlesex "A NEW MANUFACTURE
OF BLUE COLORING MATTERS
"
.
My present invention relates to a new method for manufacturing blue coloring
matters by the action of suitable oxidizing agents upon the products of the
reductions of certain diazo-colours derived from the amido-sulphonic acids of
naphthalene and tertiary monamines (such as dimethylaniline, diethylaniline,
methyldiphenylamine &c.) in the presence of sulphuretted hydrogen in accordance
with the well known reaction discovered by Lauth.
In carrying out this invention I take one of the isomeric amidonaphthalene-
sulphonic acids known to chemists and convert it into a diazo-sulphonic acid by
acting upon it with the necessary quantity of nitrous acid or of a nitrite in the
presence of a mineral acid. This diazo-sulphonic acid is then allowed to act upon
dimethylaniline diethylaniline, or other tertiary monamines so as to produce diazo
colours of which the formulæ are:-
с.н.
CH, &C.
C₁, H. HSO, N = N. CH. N CH, C₁, H. HSO,, N = N. CH N
These diazo-colours are all orange dye-stuffs, and by preference I use the
compounds derived from those amido-sulphonic acids of naphthalene containing the
amidogen in the "beta" position, as is well understood by chemists, owing to the
greater facility with which such amido-sulphonic acids form the diazo colors above
mentioned.
The following is the process for carrying out the manufacture of the blue
coloring matter according to my invention.
First operation. Ten parts by weight of the amidonaphthalene sulphonic acid
prepared either by the action of sulphuric acid upon beta-naphthylamine, or by
reducing the nitro-sulphonic acids obtained by the action of nitric acid upon the
beta-naphthalene-sulphonic acid, as discovered by Clève, are suspended in cold
water acidulated with muriatic acid and a solution of nitrate of soda is gradually
added in such quantity as shall contain 3.09 parts by weight of pure nitrite. The
solutions after being mixed are kept well cooled and are allowed to stand for some
hours so as to form the diazo-sulphonic acid or mixture of isomeric acids as
mentioned. When the diazotising operation is complete, which is the case in about
two hours there is added a solution containing 5.4 parts by weight of dimethylaniline
or 67 parts by weight of diethylaniline dissolved in the necessary quantity of
muriatic acid, and after standing for some hours the diazo-colour begins to
separate and is completely thrown out by the addition of ammonia to the mixed
solutions
Second operation. The ammoniacal solution containing the ammonium salt of
the diazo-colour in suspension is mixed with a solution of yellow sulphide of
ammonium and the mixture kept at a temperature of 80° to 90° Centigrade till the
diazo-colour is completely reduced, as is ascertained by the mixture becoming
colourless. The reduction is much hastened by the addition of a small quantity of
zinc-dust. The solution is now rapidly cooled and made acid by means of muriatic
acid, and the sulphur and amidonaphthalene-sulphonic acid thus precipitated is
removed by filtration. The solution is then oxidised by ferric chloride or other
suitable oxidising substances till the smell of sulphuretted hydrogen is destroyed
:

page_text: when the colouring matter at once forms and is precipitated by the addition of
chloride of zinc and common salt in the usual way. The amido-naphthalene-
sulphonic acid is freed from sulphur by dissolving it in a weak solution of an
alkali, filtering and precipitating by muriatic acid, and the acid thus recovered can
be again used for the manufacture of the blue dye-stuff. The colouring matter
precipitated in the manner above described is collected on filters in order to remove
a red colouring matter which remains in the solution and is purified by dissolving in
hot water, filtering and again precipitating by zine chloride and common salt.
When collected it can be dried and is then ready for use, or it can be employed in
the form of a paste. It dyes silk and wool from a neutral or ammoniacal bath of
a fine blue shade and it can be used also for cotton with or without a mordant
according to the shades required.
The advantage of the method herein described consists in the facility with
which the diazo-colours above mentioned can be reduced by means the sulphides of
ammonium or sodium, and the ease with which the amidonaphtalene-sulphonic
acids employed can be recovered for use. I wish it further to be understood that
the operations above described may be varied in their order of application and I by
no means bind myself to the precise order as above set forth.
Having thus described the nature of my invention and in what manner the
same is to be performed, I claim:
A new manufacture of blue colouring matters by the reduction of the diazo-
colours formed from the various amidonaphthalene-sulphonic acids in conjunction
with dimethylaniline and other tertiary monamines by means of a sulphide with
or without the addition of zinc-dust and the oxidation of the products thus formed
bo means of ferric chloride or other suitable oxidising materials, substantially as
herein described
In witness whereof I the said Raphael Meldola have hereunto set my hand
and seal this sixth day of November in the year of our Lord one
thousand eight hundred and eighty two.
RAPHAEL MELDOLA. (L.S.)