AN IMPROVED PROCESS OF OXIDIZING CERTAIN MATTERS
Year: 1871

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery
:
Lane, in the 'County of Middlesex, Patent Agent, for the Inven-
tion of "AN IMPROVED PROCESS OF OXIDIZING CERTAIN MATTERS."-A
communication from abroad by Edouard Aubertin, Railway Super-.
intendent, of 13, Boulevart St. Martin, Paris.
Sealed the 20th October 1871, and dated the 3rd May 1871.
PROVISIONAL SPECIFICATION left by the said Alexander Melville-
Clark at the Office of the Commissioners of Patents, with his.
Petition, on the 3rd May 1871.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, do hereby declare the nature of
the said Invention for "AN IMPROVED PROCESS OF OXIDIZING CERTAIN MATTERS,'
to be as follows:---
3.
The Invention consists in a new mode of oxidizing various matters
capable of being oxidized by passing a current of air mixed with
vapors of such matters over sesquioxide of chromium at a dull red
heat or even at a lower temperature. The oxidation of said matters

page_text: is effected by extracting a portion of its oxygen from the oxide of
chromium, which is again restored to it by the air.
.
The matters which may be operated on in this manner are very
numerous, and include the following:-Hydrochloric acid for obtaining
chlorine; ammonia for producing nitric acid; alcohol for producing
aldehyde and acetic acid; hydro-sulphuric acid for producing sulphuric
acid, it being also obtainable by the aid of sulphurous acid. Instead
of using sesquioxide of chromium in all these reactions I may employ
chromic acid or chromates, more particularly those of iron or copper,
which act both by the oxygen of their base and by that of their acid, or
I may use alkalino or alkalino-terreous chromates, which act by first pro-
ducing a certain quantity of sesquioxide of chromium. I also use with
success the native ore of chromium (chrome iron).
In fact I may employ the greater number of compounds of chromium,
containing-this-metal in the form of an oxygenated compound.
--
The Invention thus consists in the employment, as an oxidizing agent,
of oxygenated compounds of chromium, at-a-dull red heat or lower tem-
1
£1.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alexander Melville Clark in the Great Seal Patent
Office on the 2nd November 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MELVILLE CLARK, of 53, Chancery Lanc, in the County of Middlesex,
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Third day of May, in the year of:
our Lord One thousand eight hundred and seventy-one, in the thirty-
fourth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Alexander Melville Clark, Her special licence
that I, the said Alexander Melville Clark, my executors, administrators,.

page_text: and assigns, or such others as I, the said Alexander Melville Clark, 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
PROCESS OF OXIDIZING CERTAIN MATTERS," a communication to me from
abroad by Edouard Aubertin, Railway Superintendent, of 13, Boulevart
St. Martin, Paris, upon the condition (amongst others) that I, the said
Alexander Melville Clark, my executors or administrators, by an instru-
ment in writing under my, or their, or one of their hands and seals,
should particularly describe and ascertain the nature of the said Inven-
tion, and in what manner the same was to be performed, and cause the
same to be filed in the Great Scal Patent Office within six calendar
months next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Alexander Melville Clark, do hereby
declare the nature of the 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):-
The Invention consists in a new mode of oxidizing various matters
capable of being oxidized by passing a current of air mixed with vapors
of such matters over sesquioxide of chromium at a dull red heat, or
even at a lower temperature. The oxidation of said matters is effected
by extracting a portion of its oxygen from the oxide of chromium, which
is again restored to it by the air.
The matters which may be operated on in this manner are very
numerous, and include the following:-Hydrochloric acid for obtaining
chlorine; ammonia for producing nitric acid; alcohol for producing
aldehyde and acetic acid; hydro-sulphuric acid for producing sulphuric
acid, it being also obtainable by the aid of sulphurous acid. Instead
of using sesquioxide of chromium in all these reactions I may employ
chromic acid or chromates, more particularly those of iron or copper,
which act both by the oxygen of their base and by that of their acid,
or I may use alkaline or alkalino-terreous chromates, which act by first
producing a certain quantity of sesquioxide of chromium. I also use
with success the native ore of chromium (chrome iron).
In fact I may employ the greater number of compounds of chromium;
containing the metal in the form of an oxygenated compound.

page_text: I would observe that the operation may be rendered either continuous
or intermittent, and in the latter case I first pass the vapors over the
compound of chromium and then air.
Under the influence of an oxygenated compound of chromium and of
a current of air, suitably regulated, sea salt (chloride of sodium) or
chloride of potassium becomes converted into a chromate with a base
of sodium or potassium and into chlorine, the operation requiring to
be effected at a red heat. If the sesquioxide of chromium or other
oxygenated compound of chromium be mixed with chlorido of sodium
or potassium brought to about a dull red heat, and then subjected to
the action of a gazeous current formed of a mixture of sulphurous acid
and atmospheric air, sulphate of soda is first formed and chlorine is
disengaged, which reacts in the presence of water on an equivalent
quantity of sulphurous acid, and produces sulphuric and hydrochloric
acids. The gases (after acting on the mixture of chloride and oxide)
must therefore be conducted into a condensing-apparatus containing
water. The reaction is also favored by adding steam to the mixture of
air and sulphurous acid-instead-of-using it in a dry condition. In this
reaction, as in those preceding it, the sesquioxide of chromium may
be replaced by the natural ore of chromium (chrome iron), or by a
mixture of sesquioxide of chromium with other metallic oxides. I also
reserve the right of producing bromine in the manufacture of chlorine
by this improved process, that is to say, I cause a current of hydro-
chloric acid and air to pass over the before-mentioned compounds of
chromium in the manner already described, the chlorine produced being
made to act on the mother waters of salt marshes.
Having described the nature of the Invention and the manner of
performing the same, I declare that what I claim as the Invention to
be protected by the herein-before in part recited Letters Patent is :—
1st. The novel application, as a general oxidizing agent, of sesqui-
oxide of chromium or other oxygenated compound of chromium, or a
natural ore of chromium (chrome iron), or a mixture of sesquioxide of
chromium with other metallic oxides, said matters being constantly
regenerated by the action of atmospheric air, at a dull red heat, or it
may be at a slightly lower temperature.
2ndly. I claim the application of the improved process of manu-
facturing chlorine (by oxidizing the sesquioxide of chromium or other
oxygenated compound of the same) for the production of bromine by

page_text: causing the chlorine so obtained to act on the mother waters of salt
marshes.
In witness whereof, I, the said Alexander Melville Clark, have here-
unto set my hand and seal, this Second day of November, in
the year of our Lord One thousand eight hundred and seventy-
one.
Witness,
JAS. O. DEWEY,
53, Chancery Lane,
London.
A. M. CLARK. (L.S.)