THE PREPARATION OF CHLORINE GAS
Year: 1884

page_text: '
PROVISIONAL SPECIFICATION.
I, JOHN TAYLOR, of 3, Paragon Terrace, Cheltenham, Science Master at
Cheltenham College do hereby declare the nature of my invention for THE
PREPARATION OF CHLORINE GAS to be as follows:-
•
Hydrochloric acid gas, direct from the salt-cake furnace, (or otherwise prepared)
is passed through pumice, pounded fire-brick, or other material (contained in a
suitable chamber) moistened with concentrated nitric acid: The gases formed,
consisting mainly of chlorine & nitrosyl chloride (NO Cl) with small quantities of
nitrogen tri & tetroxides, are led through pounded fire-brick saturated with strong
sulphuric acid, whereby the nitrous fumes are absorbed & the nitrosyl chloride
decomposed, thus NO Cl + H₂SO = *HCl + H NO SO, the chlorine passing on
unchanged. The hydrochloric acid gas thus reformed is again oxidized by strong
nitric acid, as above, & the products of decomposition again absorbed by con-
centrated sulphuric acid; & so a third time, & if necessary, a fourth-by which
means, chlorine, almost free from hydrochloric acid gas, is obtained, & may be used
for the preparation of bleaching powder, or otherwise. The nitrosyl sulphato
(H NO SO), formed by the absorption of the nitrous fumes & the decomposition
of the nitrosyl chloride, by the sulphuric acid, is treated with a current of steam
mixed with air, & the vapours so obtained are passed through fragments of fire-
brick kept cool by water, whereby nitric acid is re-obtained & the sulphuric acid
re-produced: The sulphuric acid thus formed may be used to re-absorb the nitrous
fumes or in the preparation of sodium sulphate (salt-cake).
COMPLETE SPECIFICATION.
I, JOHN TAYLOR, of 3 Paragon Terrace, Cheltenham, Chemist, do hereby declare
the nature of my said invention for "THE PREPARATION OF CHLORINE GAS
" 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 said Invention consists in subjecting hydrochloric acid to the action of nitrio
acid, and in causing the gaseous products thereby obtained to be acted on by

page_text: sulphuric acid. By this process chlorine almost free from hydrochloric acid is
obtainable and may be used in well known ways for making bleaching powder,
chlorate of potash and other products; whilst the nitric and sulphuric acids
employed may be regenerated or recovered so as to be used over again.
In carrying out my Invention gaseous hydrochloric acid, obtained directly from
the salt-cake furnace or in any other convenient way, is passed through a tower,
or tube or other suitablo, apparatus containing fragments of pumice stone, coke, or
other suitable inert material, through which cold strong nitric acid is allowed to
flow. The action of the nitric acid causes the formation of chlorine, nitrosyl
chloride, water, and small quantities of nitrogen tri-and-tetroxides, about two
thirds of the chlorine of the hydrochloric acid being set free. The mixed gases,
chlorine, nitrosyl chloride, and nitrogen tri-and-tetroxides are passed into strong
sulphuric acid; whilst the water formed is periodically removed from the bottom
of the tower or tube or other suitable apparatus. The strong sulphuric acid absorbs
the nitrous fumes, permits the chlorine to pass on unchanged, and decomposes the
nitrosyl chloride with the formation of hydrochloric acid gas, and nitrosulphuric
acid. The reformed hydrochloric acid gas along with the chlorine with which it is
mixed is a second time submitted to the action of nitric acid and the gaseous
products of that action are a second time acted on with sulphuric acid; and a
further quantity of free chlorine is thereby obtained. The resulting gas is put,
through the processes a third time or oftenor if required until it is found to consist
almost entirely of chlorine free from hydrochloric acid.
In order to regenerate the nitric acid employed, the nitro-sulphuric acid, placed
in a suitable vessel is decomposed by the gradual addition of water whilst a rapid
current of air is passed through the liquid. The nitrous vapors evolved are passed
into water contained in a series of bottles, whereby nitric acid of sufficient strength
for the operations herein before described is obtained. And by distilling the
residual liquid, containing a little nitric acid, that nitric acid is obtained, whilst
the sulphuric acid is also restored to its original condition.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declaro that what
I claim is
The process for obtaining chlorine gas in which hydrochloric acid is subjected to
the action of nitric acid and the gascous products of that action are subjected to
the action of sulphuric acid, substantially as hereinbefore described.
181 น