IMPROVEMENTS IN THE MEANS OF PRODUCING FROM ROSANILINE BLUE AND VIOLET COLOURING MATTERS SOLUBLE IN WATER
Year: 1865

page_text: PROVISIONAL SPECIFICATION left by Edward Thomas Hughes at the
Office of the Commissioners of Patents, with his Petition, on the
12th June 1865.-A communication from abroad by Prosper Monnet,
of Lyons, in the Empire of France.
I, EDWARD THOMAS HUGHES, of the Firm of Hughes and Son, Patent
Agents, 128, Chancery Lane, London, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE MEANS OF PRODUCING FROM ROSANILINE
BLUE AND VIOLET COLOURING MATTERS SOLUBLE IN WATER," a communication
to me from abroad by Prosper Monnet, of Lyons, in the Empire of France,
to be as follows:-
This Invention consists of transforming certain chemical agents upon the
salts of rosaniline for producing blue and violet colouring matters. Heretofore
the violet colouring matter has been insoluble in water, and necessitated the
use of alcohol to effect its dissolution in the process of dyeing or printing
fabrics or yarns, the use of alcohol being prejudicial to the production of fine
shades.
In the alcoholic dissolution of the ordinary violet, the colour being thrown
into the dye bath of cold water, it is precipitated in an insoluble state upon
the textile material without imparting all the brightness and freshness that
violet is capable of giving. This improved violet colour being in a state of
perfect dissolution in the dye bath produces the finest shades, the dyeing and
printing being at the same time more easily accomplished and less expensive;
the alcohol being simply omitted and replaced by water to effect the disso-
lution. This improved violet colour may be obtained by various similar
processes, two of which I will proceed to describe.

page_text: Firstly, I make a mixture of equal parts of blue, of aniline of commerce,
and sulphate of rosaniline, or any other salt of rosaniline, the proportions
being varied according to the tinge of red or blue required. One part of the
mixture is dissolved in six parts in weight of sulphuric acid at 66° Beaumé.
The dissolution is facilitated by heat, but it must not exceed 60° centigrades
(or 108° Fahrenheit), and when the dissolution is perfect the mixture is
heated to 140° centigrades (or 252° Fahrenheit), and drawn back from the
fire.
Secondly, the Invention consists in treating with sulphuric acid in the
same proportions, conditions, and degrees of temperature an insoluble violet
prepared as follows:-I heat to about 100° centrigrades (or 180° Fahrenheit)
about four kilogrammes (9 lbs. avoirdupois) of aniline of commerce, in which
is dissolved a kilogramme (about 2 lbs. 3 oz. avoirdupois) of red of aniline
(chlorhydrate of rosaniline, for example), the dissolution being complete I
throw into the mixture two hundred grammes (about 7 oz. avoirdupois) of
acetate of soda, dry and powdered; the temperature is then raised to
170° centigrades (or 306° Fahrenheit); the red changes by little and little to
violet, the tint of which becomes of a deeper blue if the reaction is prolonged.
Arrived at the desired shade the vessel is taken from the fire, and after
cooling I add with care four kilogrammes, eight hundred grammes (4k.
800 g. or about 10 lbs. 12 oz. avoirdupois) of white hydrochloric acid of
commerce at 22° Beaumé. This mixture is kept boiling for some minutes,
the violet is dissolved in the hydrochlorate of aniline which is produced, and
by the help of this dissolution. the high temperature and excess of acid, the
double salt of rosaniline, and bleuine (I mean by bleuine the basic matter of
the blue of aniline) in its insoluble state (common or ordinary violet) is pro
duced in a condition not easily obtained by any other way. The liquid and
cold mixture is poured into ten times its weight of cold water, and the violet
is precipitated and collected upon a filter, washed and dryed. It is the
common insoluble violet thus obtained that is treated with six times its weight
of sulphuric acid in following the directions given for the first processs.
If I shew here the preparation of the common or ordinary violet which is
insoluble in water, it is because the violets of commerce being found in the
conditions of process often irregular, important to know the definite product
upon which the sulphuric acid is to act. Obtained with either of the before-
mentioned violets, the new violet consists of a powder of a bright metallic
appearance, and has a greenish reflection similar to the wings of cantharides,
it being perfectly soluble in about 200 parts of boiling water.
The solution obtained from the violet, treated or not treated with the

page_text: solution of potash, is a little coloured, it only requires the addition of a small
quantity of vegetable or mineral acid (by preference sulphuric acid) to
produce all the requisite richness of colour. Without the addition of the acid
the violet has little affinity for the textile fabrics. The dyeing and printing
of the tissues is effected in the manner usually adopted for treating other
aniline colours.