IMPROVEMENTS IN DYEING, PRINTING, AND OTHER OPERATIONS BASED ON CHEMICAL REACTIONS
Year: 1866

page_text: PROVISIONAL SPECIFICATION left by Alfred Paraf at the Office of
the Commissioners of Patents, with his Petition, on the 2nd June
1866. A communication from abroad by Mathias Paraf-Javal, of
Thann, France.
I, ALFRED PARAF, of the City of Manchester, in the County of Lancaster,
Chemist, do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN DYEING, PRINTING, AND OTHER OPERATIONS BASED ON CHEMICAL REACTIONS,"
being a communication to me from abroad by Mathias Paraf-Javal, of Thann,
France, to be as follows:-
The manufacture of certain precipitates, either in the isolated state, or in
suspension in liquids, is difficult and expensive, and some chemical operations
are applied with much trouble by the great quickness in which they are
produced. I overcome these inconveniences by fixing or causing to be fixed
temporarily or definitively upon certain substances those precipitates by
stopping or moderating for a time those chemical reactions, for instance, in
order not to lose the prussiate of potash contained in a bath, it is usually
boiled down to crystillization, or if there is a large quantity of water present
it is precipitated by a salt of iron. "In this case in taking account of the time
which the prussiate of iron requires to deposit, then washing it, decomposing
it by potash, and the separation by washing of the prussiate of potash from
the oxyde of iron, it is easily perceived that those operations are not only long
and expensive, but that immense sized vessels will be required for the quantity
of prussiate. In order to overcome these inconveniences, I fix the oxyde of

page_text: iron upon any substances which wash easily, such as wood, cotton, or calico.
If I operate, for instance, with calico I fix the iron in the fibre by the
known methods, wash it, dye in the solution containing the prussiate which
I want to obtain, wash again, and then decompose it in solution of potash
in the necessary quantity of water, and in this manner a long and expensive
operation becomes short and cheap. In the same manner I can obtain out of
liquids containing alcaloides, such as strichnine, quinine, and similar alcaloides,
those alcaloides in preparing cloth in tannic acid passing through the alcaloide
bath which the tannic acid absorbs, and decomposing or distilling afterwards
with any alkali to liberate again those alcaloides.
In another case in the manufacture of aniline mauve, either by chromates,
permanganates, or similar salts, there is a great quantity of a black precipitate
found which has to be separated by washing from the mauve coloring matter.
Not only this black is almost of no value, but the washing forms a very long
operation. I overcome this by fixing in the fibre the chromate, permanganate,
or similar salts, and then by dyeing in a salt of analine both black and mauve
are fixed in the fibre. After dyeing, I wash first in an alkaline water in
order to separate it from the brown, then by boiling in a high-pressure appa-
ratus (or bleaching pan for instance) with alcoholized water, I dissolve only
the pure mauve, and the black remains fixed in the fibre. In this manner
through a simple operation I get at once a pure mauve, and a black which
was lost before has served in this case to dye goods. I especially produce a
cheap and fast mauve in this way of operating by using the oxide of manga-
nese fixed in the fibre. I also use the manganese salt with advantage for the
production of auiline black which remains on the cloth after the mauve has
been taken out. The same process of precipitating in the fibre I use for the
purification of aniline blues.
I have also found that the more cool is a mixture of a salt of aniline and
metal the less is it liable to decomposition, for instance, when chromic acid is
mixed with a salt of aniline it is almost decomposed at once into black, but if
mixed in a vessel remaining in a freezing mixture it keeps undecomposed as
long as the mixture is below zero. I have applied for this purpose the
freezing machine of Monsieur Carré, and in passing my cloth or yarn through
a mixture of chromic acid and aniline salt kept cold by one of these apparatus
the cloth remains of a lemon yellow color, but whenever it comes out of this
cold bath the fast black is found insoluble in the fibre.
The improvement which I have made to moderate or prevent chemical
reactions by cold is not only applicable for the above-mentioned instance, but
in a great many cases, such as thickened chromic acid which is used as a resist

page_text: upon Turkey red, or thickened bypochlorite of lime which is used as a resist
upon indigo, both of which mixtures do not keep at all in the usual - tempe-
rature, but keep any length of time in the cold state.
I have also found that substances which quickly harden and get unworkable
at the usual temperature remain soft below zero, such as plaster and water,
all kinds of cements and similar materials. Also lactarine, which is coagulated
at the usual temperature by lime or other strong alkalies remains unde-
composed below zero.