Year: 1889

page_text: 1. MATTHEW CANNON, F.C.S. M.S.C.I., of 25 Stormont Road, Lavender Hill,
in the County of Surrey, Manufacturing Chemist, do hereby declare the nature
of this invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
-
My invention relates to the manufacture of acetic acid. In making acetic acid
according to my said invention, I take the crude acetic or pyroligneous acid resulting
from the destructive distillation of wood, or I produce the crude acetic acid by
decomposing the crude acetate of lime, either brown or grey, or other acetate con-
taining tarry matter, with preferably (on account of their cheapness) hydrochloric or
sulphuric acid, and distil the same in iron, or other suitable still, connected with a
lead or other suitable condenser.
I then take the impure acid produced as above stated and digest it at a temperature
of about 140° Fah. for about 12 to 48 hours in earthenware, stone, slate or other
suitable vessel, with about three per cent. of any one of the following oxidising
agents, viz.:
1st. Binoxide of manganese, commonly known as black oxide of maganese, or
2nd. Manganate of soda or other manganate or
3rd. Permanganate of potash or other permanganate.
The hinoxide of manganese requires the longest time to digest on account of its
action taking place more slowly; the manganate or permanganate being more easily
decomposed is added gradually to the acid at the ordinary temperature, say about
60° Fah. being kept continually stirred during the whole time and afterwards raised,
by steam or some suitable means, to the temperature of 140° Fah. and kept at that
temperature until the whole of the manganate or permanganate is decomposed, this
state being known by the cessation of all effervescence.
An equivalent quantity of sulphuric or other acid, is added to decompose the
acetates formed by the decomposition of the oxidant used otherwise a loss of acetic
acid will result; when binoxide of manganese is used the sulphuric or other acid is
added at the same time, but in the case of manganate or permanganate it is pre-
ferable to add the acid after the addition of the oxidant.

page_text: The action in each case is due to the oxidation of the tarry matter into carbonic
acid (CO2), escaping as gas, by the liberation of oxygen in the nascent state from the
oxidant used.
The following equations show the reaction which takes place in each case, and also
show the proportional quantity of sulphuric acid to use.
1stly. With Binoxide of manganese showing liberation of oxygen.
2 Mn 0,2 H₂ SO
=
174
196
2 Mn SO +2 H₂ 0 + 0₂.
K, Mn, O3 + 3 H₂ SÓ¸
316
294
2 Mn SO, + K, SO₁ + 3 H₂ O + 0.
I then take the digested acid and distil in a copper or any suitable still heated by
steam or otherwise, and connected with a silver, tin or other suitable condensor.
About of the distillate, more or less if circumstances require it, is collected as
"first runnings;" this being a little coloured will requiro to go through the
digestion process again, or it may be utilized by saturating with carbonate of soda,
and so making acetate of soda, or it may be used for many purposes for which pure
acetic acid is not required. The remainder (except a small quantity of "last
runnings," about 20 of the whole, which may be separated and treated the same
as the "first-runnings") of the distillate will be colourless and free from unpleasant
taste or smell and suitable for most purposes for which pure acetic acid is required,
such as for making white lead by the modern process, white acetate of lead, emerald
green and other colours, acetate of soda, for pickling purposes and for the manufacture
of vinegar.
In the event of the acetic acid produced as above stated not being of sufficient
purity to meet the requirements of some purposes, I then take the acid through the
digestion process again with about 1 per cent. of any one of the above mentioned
oxidizing agents with the equivalent proportion of sulphuric or any other suitable
acid and again distil as before (rejecting the "first" and "last running" as before
stated); an acid of exceeding purity being then obtained. A proof of its purity from
tarry or other organic matter shall be that 100 grains measure of the acid shall not
decolorise 1 grain measure of a normal solution of permanganate of potash.
This
test being the most delicate of all for the detection of tarry or other organic
impurities, enables one to see at once that the acetic acid made by this process
compares favorably with acetic acid made by the ordinary process from acetate
of soda.
I do not bind myself to the above quantities of oxidizing agents, more or less
being required according to the quantity of tarry matter contained in the acetic acid,
neither do I bind myself that the temperature shall be 140° Fah. as higher or lower
temperatures will answer the purpose, but I find the best result is obtained at a
temperature of about 140° Fab.
The residue left in the digester or still contains the whole of the manganese con-
tained in the oxidant used and may be reconverted by the usual or any suitable
method into binoxide of manganese, manganate or permanganate of potash soda etc.,
and may be thus used continuously for the manufacture of acetic acid by my process.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
1. In the manufacture of acetic acid the use of binoxide of manganese, manganate
of soda or other manganate, or permanganate of potash or other permanganate,
together with sulphuric or other suitable acid for oxidizing the impure acetic or
pyroligneous acid.
2. The manufacture of pure acetic acid from the crude pyroligneous or acetic acid
resulting from the destructive distillation of wood or from the impure acetic acid from
the decomposition of acetate of lime or other acetate containing tarry matter by
digesting and purifying the impure acid by the oxidizing action of binoxide of
manganese, manganate of soda or other manganate, permanganate of potash or other
permanganate together with sulphuric or other suitable acid substantially as herein-
before specified.
3. The recovery of the reagents used in this improved process substantially as
above specified.
4. The improved pure acetic acid manufactured substantially as before described.
D
322 1
1 1000
MATTHEW CANNON.
W. P. Thompson & Boult,
Agents for Applicant.