Improvements in the Manufacture of Acetic Acid.
Year: 1888

page_text: Date of Application, 5th Oct., 1888 "
Complete Specification Left, 21st June, 1889-Accepted, 24th Aug., 1889
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Acetic Acid.
I, MATTHEW CANNON, F.C.S., M.S.C.I., of 25 Stormont Road, Lavender Hill,
London, S. W., manufacturing Chemist, do hereby declare the nature of this invention
to be as follows:-
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 (known commercially as lime salt) either
brown or grey, or other acetates containing tarry matter, with hydrochloric or
sulphuric acid and distil in an iron or other suitable still attached to a leaden or
other suitable condenser.
I take the impure acid and digest it in suitable earthenware slate or stone vessels
with about 3 per cent. of any of the following oxidizing agents, viz. :
1. Binoxide of manganese commonly known as black oxide of manganese, or
2. Manganate of sodium or potassium or other manganate, or
3. Permanganate of sodium or potassium or other permanganato, at a temperature
of about 140° Fahrenheit for from 24 to 48 hours. An equivalent quantity of
preferably sulphuric acid is used to decompose the above oxidants, otherwise they
would be decomposed at the expense of an equivalent of acetic acid.
I then distil the digested acid in suitable stills heated by steam or otherwise, and
connected to a silver or tin condenser.
When the acid commences to distil over about 15 of the distillate is collected as
"first runnings" which will be a little colored and will require to go through the
digestion process again, but the remainder of the distillate will be colourless and free
from any unpleasant taste or smell and suitable for most purposes, such as making
white lead by the modern process, white acetate of lead, emerald green and also for
pickling 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 can take the acid first obtained
through the digestion process again with about 1 per cent. of one of the said oxidizing
agents, and distil again, when an acid of the utmost purity is obtained.
The residuum left in the still or digester, containing the whole of the manganese
contained in the oxidizing agents above named may be reconverted by any well
known processes into binoxide of manganese, or maganates, or permanganates and
used again as before stated.
Deted this 5th day of Oatsho- 1888
W. P. THOMPSON & BOULT,
A cents
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Acetic Acid.
I, MATTHEW CANNON, F.C.S., M.S.C.I., of 25 Stormont Road, Lavender Hill,
London, S. W., 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

page_text: containing 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 condensor.
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 oxidizing
agents, viz. :-
1st. Binoxide of manganese commonly known as black oxide of manganese or
2nd. Manganate of soda or other manganate, or
3rd. Permanganate of potash or other permanganate.
The binoxide 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 preferable
to add the acid after the addition of the oxidant.
The action in each case is due to the oxidation of the tarry matter into carbonic
acid (CO) 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.
K, Mn, 0 + 3 H₂ SO, = 2 Mn SO + K, SO₁ + 3H 20 + 0,
316
294
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 require 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 "blast runnings'
about 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.

page_text: 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 runnings" 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
decolorize 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 favourably 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° Fahrenheit, as
higher or lower temperatures will answer the purpose, but I find the best result is
obtained at a temperature of about 140° Fahrenheit.
The residue left in the digester or still contains the whole of the manganese
contained 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.
Having now particularly described and ascertained the nature of the 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.
Dated this 20th day of June 1889.