IMPROVEMENTS IN THE MANUFACTURE OF CHLORINE.
Year: 1860

page_text: LETTERS PATENT to Charles Pierre Price Laurens, of Rouen, in tho
Empire of France, Professor. of Mathematics, for the Invention of
"IMPROVEMENTS IN THE MANUFACTURE OF CHLORINE.
Sealed the 20th July 1860, and dated the 21st January 1860.
PROVISIONAL SPECIFICATION left by the said Charles Pierre Price
Laurens at the Office of the Commissioners of Patents, with his
Petition, on the 21st January 1860.
I, CHARLES PIERRE PRICE LAURENS, of Rouen, in the Empire of France;
Professor of Mathematics, do hereby declare the nature of the said Invention:
for "IMPROVEMENTS IN THE MANUFACTURE OF CHLORINE," to be as follows:-
And for the purpose of avoiding any uncertainty as to the substances. I
employ, different chemists using different names for them, I have added to the
name of each substance the formula by which it is frequently. designated, and
the formula that I use are based upon the following equivalent..or atomic
weights of the said substances, viz., hydrogen =1,..oxygen = 8, chlorine=
35-46, copper = 81-68, all of which is perfectly intellegable to persons.
acquainted with chemistry..
My said Invention of improvements in the manufacture of chlorine consists
in decomposing by heat certain chlorides, particularly chloride of copper
(Cu Cl,) whereby the chloride gives off one equivalent of chlorine, and by
treating the residue with hydrochloric acid, and exposing it to the air, it

page_text: acquires another equivalent of chlorine, and is thereby made available for the
production of a further quantity of chlorine..
My method of manufacturing chlorine by means of chloride of copper, (Cu
Cl,) is as follows:-I take the hydrated chloride of copper, (Cu Cl + 2 HO)
and dry it at a temperature of from 100° to 150° Centigrade (212° to 302°
Fahrenheit,) until it becomes a yellowish brown powder; by this means the two
equivalents of water it contains are expelled and the chloride of copper (Cu Cl)
thus obtained is mixed with sand and heated in a retort similar to the cast iron
retorts used in the manufacture of coal gas to a temperature sufficient to expel
one equivalent of chlorine, but care must be taken not to allow the tempe-
rature to exceed 250° to 300° Centigrade, (432° to 572° Fahrenheit); the
chlorine given off is collected in any of the usual methods. In order to
prevent the chlorine acting injuriously on the sides of the retort, I cover the
inside of it with a coating of clay and charcoal of about a quarter of an inch in
thickness. The heat of the retort is continued until one equivalent of chlorine
is expelled from the chloride of copper (Cu CI), whereby the latter is reduced
to the subchloride (Cu, C!). The subchloride of copper (Cu, Cl) mixed with the
sand is then removed from the retort and common hydrochloric acid added, one
equivalent of pure hydrochloric acid (H CI) being added for every equivalent of
subchloride of copper (Cu 2 Cl), the subchloride of copper is by this means
dissolved, and the solution is then exposed to the air or a current of air is
forced by any convenient method through it until the whole of the subchloride
of copper (Cu, Cl) is converted into chloride of copper (Cu CI), which combining
with a certain quantity of the water which is always mixed with ordinary
hydrochloric acid is converted into hydrated chloride of copper (Cu Cl +
2 HO). This change is shewn to be complete if upon a few drops of the
solution being dropped into pure water,-no-precipitate or only a very slight
precipitate is formed. The exposure-of-the-solution_for_twelve hours to the.
air will generally be found sufficient to convert all the subchloride into chloride,
but the conversion is much more. rapid if a current of air be forced through
the solution as above mentioned. The solution is then evaporated until the
hydrated chloride of copper (Cu Cl + 2 HO) begins to cristallize, it is then
cooled and the cristals formed are collected and the water drained off, they are
then heated as above mentioned so as to deprive them of the two equivalents.
of water, or they may be reduced to powder and heated after being mixed with:
the sand as above described. The chloride of copper (Cu Cl) thus formed
may by the method above described be made use of for the production of a
further quantity of chlorine.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Pierre Price Laurens in the Great Seal Patent
Office on the 20th July 1860.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
PIERRE PRICE LAWRENS, of Rouen, in the Empire of France, Professor of
Mathematics, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-first day of January, in the year of
our Lord One thousand eight hundred and sixty, in the twenty-third
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Charles Pierre Price Lawrens, Her special licence
that I, the said Charles Pierre Price Lawrens, my executors, adminis-
trators, and assigns, or such others as I, the said Charles Pierre. Price
Lawrens, 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 nake, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN THE MANUFACTURE'
OF CHLORINE," upon the condition (amongst others) that I, the said Charles.
Pierre Price Laurens, my executors or administrators, by an 'instrument
in writing under my, or their, or one of their hands and seals, should.par-
ticularly 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 imme--
diately after the date of the said Letters Patent.
.
NOW KNOW YE, that I, the said Charles Pierre Price Lawrens, 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; that is to say:-
My Invention consists of certain improvements in the manufacture of
chlorine, the chlorine being obtained by the aid of heat from certain chlorides,.
the chlorides being, by the process herein-after described, made available for
the production of a further quantity of chlorine; and for the purpose of
avoiding any uncertainty as to the substances I employ, different chemists
using different names for them, I have in almost every-instance added to the
name of each substance the formula by which it is frequently designated, and
the formula that I have used are based upon the following equivalent or
atomic weights of the said substances, viz., hydrogen = 1, oxygen = 8,

page_text: chlorine 35-46, copper=31-68, all of which is perfectly intelligible to persons
acquainted with chemistry. I take any chloride which can be decomposed by
a moderate heat, and the chloride which I find to be best adapted for the
manufacture of chlorine according to my Invention is chloride of copper
(Cu Cl), which upon being heated gives off half its chlorine, then by treating
the residue with hydrochloric acid, and exposing it to the air, I cause it to
regain the amount of chlorine it had lost, thus making it available for the
production of a further quantity of chlorine.
I will now describe my method of manufacturing chlorine by means of
chloride of copper (Cu CI), but any other chloride which upon being
moderately heated gives off chlorine will, when treated in a manner similar to
that herein described, answer the same purpose. I take the bydrated chloride
of copper (Cu Cl + 2 HO) and dry it at a temperature of from 100° to 150°
Centigrade (212° to 302° Fahrenheit) until it becomes a yellowish brown
powder; by this means the two equivalents of water it contains are expelled,
and the residue thus obtained, which is anhydrous chloride of copper (Cu CI),
is mixed with about half its weight of sand, and heated in a retort similar to
the cast-iron retorts used in the manufacture of coal gas, to a temperature
sufficient to expel one equivalent of chlorine from every two equivalents of
chloride of copper, but care must be taken not to allow the temperature to
exceed 250° to 300° Centigrade (432° to 572° Fahrenheit).
I collect or utilise the chlorine given off in any of the usual methods. In order
to prevent the chlorine acting injuriously on the sides of the retort, I cover the
inside of it with a coating of clay and charcoal of about a quarter of an inch
in thickness.
The heat of the retort is continued until one equivalent of chlorine is
expelled from every two equivalents of the chloride of copper (Cu Cl),
whereby the latter is reduced to the sub-chloride (Cu, C1). The sub-
chloride of copper (Cu, Cl), with the sand mixed with it, is then removed
from the retort, and common hydrochloric acid added in such a proportion
that there shall be about one equivalent of pure hydrochloric acid (II CI)
for every equivalent of sub-chloride of copper (Cu, Cl); a slight excess of
bydrochloric acid is of no consequence. The sub-chloride of copper is by this
means dissolved. The solution is then exposed to the air, or a current of air
is forced by any convenient method through it until the whole of the sub-
chloride of copper (Cu, Cl) is converted into chloride of copper (Cu Cl).
The latter combining with a certain quantity of the water, which is always
mixed with ordinary hydrochloric acid, is converted into hydrated chloride of
copper (Cu Cl+2 HO.)

page_text: The conversion of 'the sub-chloride of copper (Cu, Cl) into. hydrated
chloride of copper (CuCl + 2 HO) is shewn to be complete if upon a few,
drops of the solution being dropped. into distilled water no precipitate or only,
a very slight precipitate is formed. The exposure of the solution for twelve:
hours to the air will generally be found sufficient to convert all the 'sub->
chloride into chloride, but the conversion is much more rapid if a current of
air be forced, through the solution, as above mentioned. After the conversion
of the sub-chloride into chloride the solution is evaporated until the hydrated
chloride of copper (Cu CI+ 2 HO) begins to crystallize; it is then cooled,
and the crystals formed are collected, and the water drained off. These
crystals are employed to produce a further quantity of chlorine, and for this
purpose they are heated so as to deprive them of the two equivalents of water."
This may be done either before or after they are mixed with the sand. In the
Jatter case they should be first reduced to powder. The process above
described is then repeated, and a further quantity of chlorine obtained, and the
chloride of copper may be used over and over again for this purpose, it being
only necessary from time to time to supply the accidental waste by the addition
of fresh quantities of chloride of copper.
It will be obvious to any one that there are many modes of forcing air
through the solution of sub-chloride of copper (Cu, Cl) in hydrochloric acid.
The two following methods I find to answer very well. In the first the
solution is placed in a suitable vessel, made either of wood, earthenware, or
gutta percha, or of any substance not attacked by hydrochloric acid, one end
of a tube of earthenware, glass, or gutta percha is immersed in the solution to
the bottom of the vessel, and the other end connected with a pair of bellows
or a blower. Upon the bellows or blower being worked, a current of air is
forced through the solution. The other method is to place the solution in a
vessel made of some substance not attacked by hydrochloric acid, the cover of
which fits air-tight; one end of a tube communicates with the upper part of
the vessel, and the other end with a flue or chimney having a sufficiently
strong draught. The orifice of the tube must be above the surface of the
solution in the vessel. Another tube made of some substance not attacked by
hydrochloric acid enters the vessel, the orifice being at or near the bottom
and below the surface of the solution, and the other end of this tube com-
municates with the air, but it must be above the level of the surface of the
solution. The draught of the flue or chimney sucks the air out of the vessel,.
and the air rushing in through the secondly mentioned tube, passes through
the solution.
All that I claim as my Invention is the method of obtaining chlorine by

page_text: beating chloride of copper (Cu Cl) or any other chloride which gives off
chlorine at a moderate heat, and causing the chloride of copper or other
chloride to regain the chlorine lost by treating it with hydrochloric acid,
and so making it available for the production of a further quantity of
beating chloride of copper (Cu Cl) or any other chloride which gives off
chlorine at a moderate heat, and causing the chloride of copper or other
chloride to regain the chlorine lost by treating it with hydrochloric acid,
and so making it available for the production of a further quantity of
chlorine.
In witness whereof I, the said Charles 'Pierre Price Laurens, have
horonto sot my hand and cool this Fourteenth day of July in the
chlorine at a moderate heat, and causing the chloride of copper or other
chloride to regain the chlorine lost by treating it with hydrochloric acid,
and so making it available for the production of a further quantity of
chlorine.
In witness whereof I, the said Charles 'Pierre Price Laurens, have
horonto sot my hand and cool, this Fourteenth day of July in the
year of our Lord One thousand eight hundred and sixty.
In witness whereof I, the said Charles Pierre Price Laurens, have
horounta sot my hand and cool this Fourteenth day of July in the
year of our Lord One thousand eight hundred and sixty.
C. LAURENS. (L.S.)