An Improved Process for the Production of Colouring Matters from Carbolic Acid and other Phenols.
Year: 1887

page_text: PROVISIONAL SPECIFICATION.
An Improved Process for the Production of Colouring Matters from
Carbolic Acid and other Phenols.
I, HANS JAKOB WALDER of Unterstrass near Zürich, Switzerland, Doctor of
Philosophy, do hereby declare the nature of this invention, to be as follows
One molecule of phenol is heated with one molecule of English sulphuric acid of
66° Beaume to 1350 Centigrade until the mass is light brown; then it is allowed to
cool, diluted with water to double the volume, this solution is heated to 40-50° Centi-
grade and to this liquid is added by degrees, with stirring, for each molecule of phenol
one molecule of solid nitrite of potassium or sodium, the temperature being kept
below 50° Centigrade. When all the nitrite is added the pasty mass is allowed to
cool and to it, is subsequently added 10 to 15 multiples of its volume of completely
saturated solution of common salt, the mixture is well stirred and then allowed to
stand for several hours. The separated colouring matter is filtered off, washed with a
small quantity of cold water, pressed and dried at a moderate temperature. This
colouring substance is soluble as a brown colour in water.
1 parts by weight of ẞ naphthol is heated with one unit of English sulphuric acid
of 66° B: to 160° Centigrade with continual stirring, until the mass is found to
dissolve in water to form a clear brown liquid. It is then allowed to cool a little and is
diluted with water to double its volume, the solution is heated to 40-50° Centigrade
and for each molecule of ẞ naphthol is added by degrees, with thorough stirring, one
molecule of solid nitrite of potassium or sodium, at the same time, preventing the
temperature from exceeding 50° Centigrade. When all the nitrite is added the
mixture is allowed to cool and to the pasty mass is added 10-15 multiples of its
volume, of completely saturated solution of common salt, the liquid is well stirred and
subsequently allowed to be at rest for several hours. It is then filtered and the
precipitate washed with a little cold water pressed and dried at a moderate
temperature.
This colouring matter is soluble as a brown red colour in water.
11 parts by weight of Resorcine are heated with 10 parts of English sulphuric.
acid of 66° B with continual stirring, to 135° Centigrade, until the mass is coloured

page_text: cherry red; it is then allowed to cool a little and diluted with water to double its
volume and heated to 40 to 50° Centigrade. Subsequently for each molecule of
Resorcine is added to the liquid by degrees, with stirring, one molecule of solid nitrite
of potassium or sodium, stirring, at the same time preventing the temperature from
exceeding 50° Centigrade. When all the nitrite is added the mixture is allowed to
cool and to the paste is added with stirring about 10 to 15 multiples of its volume of
saturated solution of common salt and the mixture is allowed to stand for several
hours the precipitate is then filtered off, washed with a little cold water, pressed
and dried.
This colouring matter is soluble as a brown colour.

page_text: Carbolic Acid and other Phenols.
I, HANS JAKOB WALDER of Unterstrass near Zürich, Switzerland, Doctor of
Philosophy, do hereby declare the nature of my invention, and in what manner the
same is to be performed to be particularly described and ascertained in and by the
following statement:-
This invention consists in a process for the formation of colouring matter or
matters by the action of nitrous acid or nitrites on the monosulpho-acids of
phenols.
In carrying out the invention one molecule of phenol is heated with one molecule
of English sulphuric acid of 66° B. to 135° Centigrade until the mass is light brown ;
then it is allowed to cool, diluted with water to double the volume, this solution is
heated to 40-45° Centigrade and to this liquid is added by degrees with stirring for each
molecule of phenol one molecule of solid nitrite of potassium or sodium the temperature
being kept below 50° Centigrade. When all the nitrite is added, the pasty mass is
allowed to cool and to it, is subsequently added 10 to 15 multiples of its volume of
completely saturated solution of common salt, the mixture is well stirred and then
allowed to stand for several hours. The separated colouring matter is filtered off
washed with a small quantity of cold water, pressed and dried at a moderate
temperature.
This colouring substance is soluble as a brown colour in water.
1 parts by weight of ẞ naphthol is heated with one unit of English sulphuric acid
of 66 B. to 160 Centigrade with continual stirring, until the mass is found to
dissolve in water to form a clear brown liquid. It is then allowed to cool a little and
is diluted with water to double its volume, the solution is heated to 40-50° Centigrade
and for each molecule of ẞ naphthol is added by degrees with thorough stirring one
molecule of solid nitrite of potassium or sodium at the same time preventing the
temperature from exceeding 50° Centigrade. When all the nitrite is added the mixture is
allowed to cool and to the pasty mass is added 10-15 multiples of its volume, of
completely saturated solution of common salt, the liquid is well stirred and subse-
quently allowed to be at rest for several hours. It is then filtered and the precipitate
washed with a little cold water pressed and dried at a moderate temperature.
This colouring matter is soluble as a brown red colour in water.
11 parts by weight of Resorcine are heated with 10 parts of English sulphuric
acid of 66° B. with continual stirring to 135° Centigrade, until the mass is coloured
cherry red, it is then allowed to cool a little and diluted with water to double its
volume and heated to 40 to 50° Centigrade. Subsequently for each molecule of
Resorcine is added to the liquid by degrees with stirring one molecule of solid nitrite
of potassium or sodium, at the same time preventing the temperature from exceeding
50 Centigrade. When all the nitrite is added the mixture is allowed to cool and to

page_text: the paste is added with stirring about 10 to 15 multiples of its volume of saturated
solution of common salt and the mixture is allowed to stand for several hours; the
precipitate is then filtered off, washed with a little cold water, pressed and dried.
The colouring matter is soluble as a brown colour.
Having now particularly described and ascertained the nature of my said invention,
and in what manner the same is to be performed, I declare that what I claim is:―
For the production of colouring matter or matters :
1. The treatment of monosulpho-acids of phenols by or with nitrous acid or nitrites
and common salt.
2. The herein described process of heating phenols with English sulphuric acid
cooling and diluting with water to the double volume, heating this solution to
45-50 Centigrade and adding to the same nitrite of potassium or sodium and
subsequently adding 10-15 multiples of its volume of saturated solution of common
salt.
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