Improvements in the Manufacture of Acetic Acid and Soluble Acetates.
Year: 1889

page_text: Date of Application, 14th Dec., 1889-Accepted, 18th Jan., 1890.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Acetic Acid and Soluble
Acetates.
JAMES EDWARD JOHNSON-JOHNSON F.I.C. F.C.S. of Crown Chemical Works
Marsh Gate Lane, Stratford, in the County of Essex, 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 from Acetates decom-
posable by hydrochloric acid gas and soluble salts of acetic acid from other salts of
acetic acid by mutual decomposition with salts of the chlorides.
My process is as follows:-
1-Production of Acetic Acid. According to my said Invention I take and mix
about equal weights of the acetate to be operated upon and water (employing, by
preference on account of its cheapness a crude calcium acetate, known commercially
as "lime salt"-acetate of sodium, acetate of potassium, and acetate of lead, etcetera,
would however, answer my purpose) in cast iron stills of usual shape or other suitable
vessels of about one thousand (1000) gallons capacity adapted to withstand fire or
steam heat having strong lids fixed thereto together with a suitable still head for
connection to a condenser, the stills being fitted inside with ordinary stirring apparatus
to keep the thick liquid in motion, and an opening through which a pipe is inserted to
admit the gas hereinafter inentioned. Hydrochloric acid gas is then by means of the
pipe referred to above, forced through or into the semi liquid mass (which is maintained
in motion all the time by the stirrer). The hydrochloric acid gas is absorbed by the
acetate solution and when the mass is thoroughly saturated with the gas-one hundred
parts of calcium acetate of eighty per cent. (80%) require about fifty six (56) volumes
of hydrochloric acid gas--the flow of the latter is stopped-the necessary heat is
applied to the stills (which are connected with ordinary condensing worms the whole
apparatus forming a distilling plant of usual pattern) and the acetic acid is distilled
off, calcium chloride remaining behind in the stills. Decomposition baving taken place
in accordance with the equation :-
----
×2 113 ₹2)2 + 2 = 2021
2. In making soluble acetates from other salts of acetic acid I proceed in this part
of my invention as follows:-Calcium acetate in a semi liquid state (as in the previous
case) is mixed with the necessary quantity of the chloride salt capable of effecting the
decomposition of the acetate. Taking sodium chloride as a type and for an example
the quantities I employ are one hundred (100) parts of calcium acetate of eighty per
cent. (80%) and sixty five (65) parts of dry sodium chloride. A similar description
of apparatus may be employed, as previously described, but without the opening or
pipe to convey the hydrochloric acid gas. The mass is heated to about two hundred
and fifty degrees (250°) Fahrenheit and maintained in motion during the operation by
the stirrer till decomposition takes place in accordance with the equation :-
Ca (C₂ H¸ O₂)2 + 2 Na Cl = 2 Na C, H, O, + Ca Cl₂.

page_text: after adding a carbonate or hydrate of the base which is to displace the base in the
acetate operated upon (in this case calcium). To make this operation more clear,
I take, for instance, calcium acetate, in solution, and heated to about two hundred and
fifty degrees (250°) Fahrenheit, as before, add thereto the equivalent proportion of
sodium carbonate or sodium hydrate (stirring all the time) and saturate the mixture
with hydrochloric acid gas, or I decompose the calcium acetate solution first, by
hydrochloric acid gas and then add the carbonate of sodium or hydrate of sodium.
The result is similar by either' method and the equations "a" and "" as under, will
indicate the reactions :-.
a
"Calcium acetate, carbonate of sodium and hydrochloric acid gas :—
"6" Calcium acetate, hydrate of sodium and hydrochloric acid gas:-
2 Na C, H, O₂+ Ca Cl₂ + 2 H₂O
Ca (C2H3O2)2 + 2 Na HO + 2 H CI
=
forming acetate of sodium, calcium chloride and water.
The acetate so formed in each case may be separated by any well known method.
I can also treat the weak and impure acetic acid (pyroligneous acid) resulting from
the destructive distillation of wood &c. by my process, by neutrallizing such acid with
an alkali or alkaline earth (such as sodium or calcium) in the ordinary way and then
treat the acetate liquor so formed as set forth above.
I do not bind myself to the exact quantities or proportions stated above as they
may be varied according to the quality and the nature of the acetate operated
upon.
I am aware that it has formerly been proposed to obtain glacial or nearly glacial
acetic acid by acting upon acetate of lime with dry hydrochloric acid gas, but I make
no claim to such process.
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 hydrochloric acid gas, as above
specified.
2. The improved method of producing acetic acid by forcing hydrochloric acid gas
through or into an acetate (preferably acetate of calcium) in a semi liquid condition
until the acetate is sufficiently saturated and then distilling off the acetic acid
substantially as set forth.
3. The improved acetic acid manufactured substantially as hereinbèfore described.
4. The improved method of producing soluble salts of acetic acid from acetates by
either adding a suitable salt of the chlorides to the solution of an acetic acid salt or
by decomposing the acetate in solution by forcing through the material hydrochloric
acid gas before or after mixing carbonates or hydrates of the base which is to displace
the base in the acetate operated upon-substantially as set forth.
5. The treatment of weak and impure acetic acid (pyroligneous acid) and proceeding
substantially as set forth.
Dated this 14th day of December 1889.