IMPROVED NEW COLORING MATTERS
Year: 1879

page_text: PROVISIONAL SPECIFICATION left by Felix de Lalande at the Office of the
Commissioners of Patents on the 4th July 1879.
FELIX DE LALANDE, of No. 22, Rue Denfert Rochereau, Paris, in the Republic of
France, Engineer. "IMPROVED NEW COLORING MATTERS."
These matters are obtained in treating with oxidising agents the sulpho-
conjugated derivatives of secondary or tertiary aromatic amines, and especially
those which contain once or oftener the radical benzyle.
1°. Preparation of sulpho-conjugated derivatives:-Sulphuric acid gives in general
by its action on the amines above indicated several derivatives, some but slightly
soluble in water, others more soluble in water, according to the extent of the action
of sulphuric acid.
A. Preparation of the insoluble sulpho-conjugated derivatives:-
Take for example,―
Dibenzylaniline
10 parts.
Sulphuric acid at 66° Baumé, 30 to 40 parts, and raise the temperature to say
about 150 to 170 degrees centigrade (301 to 336° F.); at the end of 2 to 3 hours
the reaction is finished, and this may be recognised by the product being almost
entirely soluble in an alkaline water. The mass is then poured into water and the
excess of sulphuric acid is removed by washing with water.
B. Preparation of the soluble sulpho-conjugated derivatives :-
The insoluble sulpho-conjugated acid "A" proceeding from the preceding
operation is dried and treated by 2 to 4 times its weight of fuming sulphuric acid
at a temperature of about 140 to 160 degrees centigrade (282 to 318° F.). The
operation is ended when the product has become completely soluble in water.
The same soluble sulpho-conjugated derivative may be obtained by treating
directly the dibenzylaniline by a greater quantity (4 to 6 parts) of fuming sulphuric
acid at the same temperature.
According to the same conditions the sulpho-conjugated derivatives of other
secondary or tertiary aromatic amines may be prepared.
2°. Preparation of coloring matters :—
A¹. Preparation of the coloring matters from the insoluble sulpho-conjugated
derivatives—
Dissolve in a sufficient quantity of caustic soda the sulpho-conjugated acid "A"
proceeding from 10 parts of dibenzylaniline, for example; next add a variable
quantity of bichromate of potassium (say from 1¹, to 3 parts), which is previously
0317

page_text: dissolved in water, then pour into the mixture an excess of acetic acid. The
reaction commences at the ordinary_temperature; in order to terminate the reaction,
the temperature is elevated to about 60 or 100 degrees centigrade (140 to 212°-F)
The coloring matter thus formed is precipitated by chloride of sodium collected
by filtration mixed with 2 to 3 parts of acetate of soda and dried.
B¹. Preparation of the coloring matters from the soluble sulpho-conjugated
derivatives:-
--The-soluble-sulpho-conjugated--derivative "B"-proceeding from 10 parts of
dibenzylaniline prepared by the above indicated process is poured into water and
saturated with caustic lime and then separated from the sulphate of lime by
filtration. Next the quantity previously indicated of bichromate of potassium (say
1 to 3 parts) is added to the solution, then add an excess of acetic acid. If
necessary the temperature is raised to about 100 degrees centigrade (212° F.) in
order to bring the reaction to an end. Then saturate with caustic soda and
precipitate with chloride of barium the remaining sulphates and the coloring
matter formed, then pass through a filter, wash the precipitate and extract the
coloring matter from the precipitate with a boiling solution of carbonate of soda.
The commercial product is obtained by evaporating the liquid.
The same process is applicable in the same conditions to the sulpho-conjugated
derivatives of other secondary or tertiary aromatic amines.
These coloring matters may also be produced directly upon fabrics or tissues
previously mordanted by means of oxidizing products; they are then dyed by means
of sulpho-conjugated derivatives.
Other oxidizing bodies can be employed to produce the reactions previously
referred to; for example, the permanganate of potassium in alkaline or in acid
solution, the chloride of copper mixed with chloride of sodium, the per chloride of
iron, and other suitable matters.
The coloring matters thus prepared are acids more or less soluble in water whose
alkaline salts are in general slightly colored. These salts may be employed in the
manner of Nicholson's blue by dyeing in neutral or alkaline baths and completing
the dyeing by passing the objects through an acid bath or by dyeing directly in
acid baths; the colored acid soluble in the water fixes itself readily upon the tissues
or fabrics.
By the process described coloring matters are obtained of variable shades; these
shades are generally green, which can approach more or less to blue shades.
The secondary or tertiary aromatic amines which I can employ in order to
prepare these coloring matters are principally monobenzylaniline, and the products
derivable from it by the substitution of alcoholic radicals, dibenzylaniline, the
mono and the dibenzyl derivatives of liquid toluidine, benzyldiphenylamine, and
similar compounds.