AN IMPROVED SYSTEM OF MANUFACTURING SALTS, SULPHATES, AND ACETATES OF CHROME, AND OF APPLYING THEM AS MORDANTS IN DYEING AND PRINTING TEXTILE SUBSTANCES, BOTH ANIMAL AND VEGETABLE
Year: 1865

page_text: LETTERS PATENT to Jean Henri Chaudet, living at Rouen, Rue des
Emmurées, No. 14, Working Chemist, for the Invention of "AN
IMPROVED SYSTEM OF MANUFACTURING SALTS, SULPHATES, AND ACETATES OF
CHROME, AND OF APPLYING THEM AS MORDANTS IN DYEING AND PRINTING
TEXTILE SUBSTANCES, BOTH ANIMAL AND VEGETABLE."
Sealed the 16th January 1866, and dated the 21st July 1865.
PROVISIONAL SPECIFICATION left by the said Jean Henri Chaudet at
the Office of the Commissioners of Patents, with his Petition, on the 21st
July 1865.
I, JEAN HENRI CHAUDET, living at Rouen, Rue des Emmurées, No. 14,
Working Chemist, do hereby declare the nature of the said Invention for
"AN IMPROVED SYSTEM OF MANUFACTURING SALTS, SULPHATES, AND ACETATES
OF CHROME, AND OF APPLYING THEM AS MORDANTS IN DYEING AND PRINTING
TEXTILE SUBSTANCES, BOTH ANIMAL AND VEGETABLE," to be as follows:-
Sulphurous acid is a powerful reducer of oxygenic bodies, and possesses the
property of bringing back to a state of base chromic acid either isolated or in

page_text: combination. By causing a current of sulphurous acid to pass into a
solution of no matter what chromate the chromic acid is disoxygenated and
returned to a state of oxide. It forms sulphuric acid, which combines with
the oxide of chrome produced, as also with the primitive base combined with
the chromic acid. In this reaction, independently of the sulphates formed,
there are also produced a certain quantity of sulphites. It is this conversion
of the chromates into sulphites and sulphates which I have essayed to utilize
in order to obtain cheaply salts of chrome. I operate in the following
manner: In a cast-iron retort (gourd shaped) forming part of the bellows I
introduce a certain quantity of sulphur to which I set light. This retort
communicates with the washer which conducts to the reducer containing
chromate in solution. Putting the bellows in motion the sulphurous acid
produced by the combustion of the sulphur is pushed into the solution of
chromate which takes it up, and the azote of the atmospheric air disengages
itself from the preparation. If bi-chromate of potash or of soda is employed,
sulphates and sulphites of chrome and of potash or soda are formed, which
remain dissolved. If chromate of lime be employed sulphate of lime is formed,
which is precipitated, and sulphate of chrome which remains in solution. It
is the same with chromates of lead and baryta. By adding to the chromates
their equivalent in sulphuric acid of the base combined with the chromic acid
no sulphites are formed, and the operation is more rapid. It is by means of
the salts of lime, of baryta of lead, or other analogous salts, that I obtain
sulphate of chrome of fairly pure quality, separating by filtration the insoluble
sulphates so formed. In preference I employ bi-chromate of lime produced
direct by the treatment of chrome ores by lime. It is easy to produce
hydrated oxide of chromo by means of sulphate obtained as just stated, it
suffices to precipitate it by means of ammonia or the alkaline carbonates.
This oxide of chrome serves advantageously to color glass and porcelain. The
sulphate of chrome so obtained is a good mordant for wool and silk used with
divers tinctorials by which shades of all hues are obtained. For cotton and
textile vegetable matters I employ the acetates, citrates, and tartrates of
chrome, which obtain casily by double decomposition. By employing soluble
salts of chrome (sulphate and acetate of protoxide and sesqui-oxide of
chrome as mordants) fast colors are obtained, and such have not been obtainable
by the mordants hitherto used. In order to simplify the application of oxido
of chrome as mordant, I determined to produco the conversion of chromic
acid to oxide of chrome on certain textile substances, such as wool, by employing
the bi-chromate of potash as mordant, I arrived at the desired result by putting
in contact with the textile matter mordanted by bi-chromate of potash some

page_text: reducing body, such as sulphurous acid, the alkaline sulphites, or other
bodies which possess the property of returning the chromic acid to a state
of oxide. After this operation the substance is washed, and afterwards dyed
the desired color. The conversion by reducers of the chromic acid into oxyde
of chrome on textile substances furnishes coloring similar to those obtained
by the employ of salts of chrome as mordant. To obtain mixed colors a
mordant with several colorants is employed, and even several mordants with one
or more colorants. And shades may be obtained by employing simultaneously
my mordants of chrome in conjunction with the old and well-known
mordants.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Jean ITenri Chaudet in the Great Seal Patent Office on the
19th January 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JEAN
HENRI CHAUDET, living at Rouen, Rue des Emmurées, No. 14, Working
Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-first day of July, in the year of our Lord
One thousand eight hundred and sixty-five, in the twenty-ninth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Jean Henri Chaudet, Her special licence that I, the said Jean Henri
Chaudet, my executors, administrators, and assigns, or such others as I, the said
Jean Henri Chaudet, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "AN IMPROVED
SYSTEM OF MANUFACTURING SALTS, SULPHATES, AND ACETATES OF CHROME, AND OF
APPLYING THEM AS MORDANTS IN DYEING AND PRINTING TEXTILE SUBSTANCES, BOTH
ANIMAL AND VEGETABLE," upon the condition (ainongst others) that I, the said
Jean Henri Chaudet, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately after the
date of the said Letters Patent.

page_text: NOW KNOW YE, that I, the said Jean Henri Chaudet, do hereby
declare the nature of my said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement :-
Sulphurous acid is a powerful reducer of oxygenic bodies, and possesses the
property of bringing back to a state of base chromic acid either isolated or in
combination. By causing a current of sulphurous acid to pass into a solution
of no matter what chromate, the chromic acid is disoxygenated and returned
to a state of oxide. Sulphuric acid is thus formed, which combines with the
oxide of chrome produced, as also with the base primitively combined with
the chromic acid. In this reaction independently of the sulphates formed
there are also produced a certain quantity of sulphites. It is this conversion
of the chromates into sulphites and sulphates which I have essayed to utilizo
in order to obtain chiedy salts of chrome. I operate in the following manner :-
In a cast-iron retort forming a continuation of the bellows or blowing machine
I introduce a certain quantity of sulphur to which I set light. This retort
communicates with the washer, which conducts to the reducer containing
chromate in solution. On putting the bellows in motion the sulphurous acid
produced by tho combustion of the sulphur is pushed into the solution of
chromate, which takes it up, and the azote of the atmospheric air disengages
itself from the apparatus. If bi-chromate of potash or of soda is employed,
sulphates and sulphites of chrome, and of potash or of soda are formed, which
remain dissolved. If chromate of lime be employed sulphate of lime is
formed, which precipitates itself and sulphate of chrome which remains in
solution. It is the same with chromates of lead and baryta. By adding to
the chromates the equivalent in sulphuric acid of the base combined with the
chromic acid no sulphites are formed, and the operation is moro rapid. It is
by means of the salts of lime, of baryta, of lead, or other analogous salts, that I
obtain sulphate of chrome of fairly pure quality in separating by filtration the
insoluble sulphates so formed. In preference I employ the bi-chromate of
lime obtained direct from the treatment of chrome oro by lime. It is
easy to produce economically hydrated oxide of chromo by means of the
sulphate obtained as just stated, it suffices to precipitate it by means of
ammonia or the alkaline carbonates. This oxide of chrome may be used
advantageously in the coloring of glass and porcelain. I use the sulphate and
nitrate of chrome as a mordant for wool and silk, in order to obtain entirely
novel shades of color with the divers tinctorial matters. For cotton and
textile vegetable matters I employ the acetates, nitrates, citrates, and tartrates
of chrome which I obtain easily by double decomposition.

page_text: Here are the colorations given by the salts of chrome employed as mordant
with the following tinctorial matters :-
Campeachy, blue and black blue.
Red wood, violet red.
Sanders, red.
Yellow or Jamaica rosewood (Mo-
rustinctoria), golden yellow.
Quercitron, clear yellow.
Woad or resida luteola, emerald
yellow.
Persian berries, straw colour.
Roucou, flesh colour.
Curcuma, copper yellow.
Fustic, mahogany yellow.
Madder, fallow red.
Gall nut, fallow brown.
Sumach, yellow brown.
Catechu, sienna clay.
Cochineal, purple red.
Carmeline, carmine red..
Aniline, violet and fuchsia.
Yellow prussiate, green.
Orchilla, violet red.
Red prussiate, green blue.
I pass over in silence the extracts of the different tinctorial matters of
which the colorations with salts of chrome agree with the immediate coloring
principles above set forth.
By employing the solublo salts of chrome (sulphate, nitrate, and acetate of
protoxide and sesqui-oxide of chrome) as mordant fast colors are obtained,
such as could not be obtained with the mordants hitherto used, for example,
the colours obtained no longer turn green on exposure to the air like those
obtained by the use of bi-chromate of potash.
I explain this difference of fastness in the following manner :-In employing
the usual bichromate of potash as a mordant, the chromic acid of the salt
oxidizes the textile matter, and the coloring which is applied in such wise that
the said coloring matter consumes and slowly destroys itself by this energetic
oxidation produced by the oxygen arising from the chromic acid. The
chromic acid in transmitting its oxygen to the coloring matter transforms itself
into oxide of chrome, which is naturally green. It follows that the coloring
matter being more or less destroyed the green oxide of chrome appears, and
the primitive shade becomes greenish. It is not so in employing the chrome
in the state of oxide or base as mordant, the affinity of the oxide of chrome
for the textile and coloring matters being considerable, the result is unalterable
ternary compounds, and each of the elements composing them being fixed,
they have no longer anything to mutually exchange and destroy themselves.
In order to simplify the application of oxide of chrome as mordant, I deter-
mined to produce the conversion of the chromic acid into oxide of chrome on
certain textile substances, such as wool, by employing the bi-chromate of
potash as mordant. I have arrived at the desired result by putting in contact
with the textile matter, mordanted by bi-chromate of potash, a reducing body,

page_text: such as sulphurous acid, the alkaline sulphites, the organic acids, alcohol,
sugar, and it congeners, and other bodies which possess the property of
returning the chromic acid to a state of oxide, and after this operation the
substance is washed, and afterwards dyed the desired color. The conversion
by reducers of the chromic acid into oxide of chrome on textile substances,
furnishes colorations similar to those obtained by the employment of salts of
chrome as mordant. To obtain mixed colors, a mordant with several coloring
matters is employed, and often several mordants with one or more colorants.
And these shades may be obtained by employing simultaneously my mordants
of chrome in conjunction with old and well-known mordants.
The manufacture and application of the salta of chrome as a mordant in
dyeing and printing textile substances being entirely new, I claim their exclu-
sive manufacture and application in all the cases defined in this Specification.
In witness whereof, I, the said Jean Henri Chaudet, have hereunto set
my hand and seal, this Fifteenth day of January, in the year of our
Lord One thousand eight hundred and sixty-six.
J. H. CHAUDET. (LS.)