Improvements in the Preparation of Acetic and Oxalic Acids.
Year: 1893

page_text: Date of Application, 8th Dec., 1893
Complete Specification Left, 28th Aug., 1894-Accepted, 8th Dec., 1894
PROVISIONAL SPECIFICATION.
Improvements in the Preparation of Acetic and Oxalic Acids.
I, COUNT HENRI PLATER-SYBERG of 81 Rue de la Boëtie, Paris, France,
Gentleman, do hereby declare the nature of this invention to be as follows:-
This invention relates to a process for preparing acetic and oxalic acids which is
based upon the following experimental facts.
Various hydrates of carbon such as cellulose in the presence of caustic alkalies
give rise to numerous products of which acetic acid is one. By the intervention of
heat the action is accelerated, and beyond a certain temperature oxalic acid makes
its appearance beside the acetic acid. If with the intervention of heat oxydizing
agents (air or suitable chemical products) are coupled, the quantity of these two
acids is still more notably increased, and their relative proportions vary with the
temperature employed, the proportion of oxalic acid increasing with the tempera-
ture up to a certain limit.
Upon the foregoing I base my process for preparing on a manufacturing scale
acetic acid and oxalic acid by means of materials rich in carbon hydrates. I treat
these materials first with a hot alkaline lye and then with an oxydizing agent.
According to the working temperature employed I can obtain either acetic acid, or
acetic acid with a proportion of more or less oxalic acid.
As the primary materials I by preference use various kinds of wood or else
the mosses which are found in such large quantities in the bogs of Russia and
Lithuania.
The wood reduced to chips, in order to afford as large a surface as possible
for acting upon, or the moss, is soaked in a boiling soda or potash lye, or by
preference a mixture of these two lyes. Thereupon 1 cause the oxydizing agent
to act, but under the following slightly differing conditions according as I wish
to obtain merely acetic acid or else acetic acid and oxalic acid.
Į
In the former case I prefer to use wood treated as just above described;
submit it to the action of the oxydizing agent which may either be a current
of hot air, or a mixture of steam and air at a temperature of 110 to 130° C.
(230 to 266° F.). A product is thus obtained which when treated with water
disintegrates completely, the acetic acid remaining in solution in the form of
alkaline acetate, and a residue is got of wood pulp or cellulose which is not
paper stock.
decomposed or encumbered with impurities and which is suitable for
If it be desired to obtain simultaneously acetic acid and oxalic acid, a mixture
of steam and air is used as the oxydizing agent but at a higher temperature up
to 140° C. (284° F.) the fibre of the wood is then strongly attacked and the product
obtained, treated with water, dissolves almost entirely leaving only a slight
residuum. The solution contains acetic acid together with a material quantity of
oxalic acid. The acids may be eliminated by the ordinary processes.
The mosses decompose more easily than the wood and are particularly suitable
for obtaining a large proportion of oxalic acid. If, after the first soaking, the moss
in boiling alkaline lye, it is exposed to the action of a. current of steam and super-
heated air, it will be decomposed and at a temperature of 110° C. (230° F.) and
upwards give off oxalic acid together with acetic acid; the increase in temperature
will only accelerate the reaction and vary to a certain degree the proportions of the
two acids formed.
Dated this 8th day of December 1893.

page_text: Improvements in the Preparation of Acetic and Oxalic Acids.
I, COUNT HENRI PLATER-SYBERG of 81 Rue de la Boëtie, Paris, France,
Gentleman, 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 :-
This invention relates to a process for preparing acetic and oxalic acids which is
based upon the following experimental facts.
Various hydrates of carbon such as cellulose in the presence of caustic alkalies
give rise to numerous products of which acetic acid is one. By the intervention of
heat the action is accelerated and beyond a certain temperature oxalic acid makes
its appearance beside the acetic acid. If with the intervention of heat oxydizing
agents (air or suitable chemical products) are coupled, the quantity of these two
acids is still more notably increased, and their relative proportions vary with the
temperature employed, the proportion of oxalic acid increasing with the temperature
up to a certain limit.
treat
Upon the foregoing I base my process for preparing on a manufacturing scale
acetic acid and oxalic acid by means of materials rich in carbon hydrates.
these materials first with a hot alkaline lye and then with an oxydizing agent.
According to the working temperature employed I can obtain either acetic acid, or
acetic acid with a proportion of more or less oxalic acid.
As the primary materials I by preference use various kinds of wood or else the
mosses which are found in such large quantities in the bogs of Russia and
Lithuania.
The wood reduced to chips in order to afford as large a surface as possible for
acting upon or the moss is soaked in a boiling soda or potash lye, or by preference
a mixture of these two lyes. Thereupon I cause the oxydizing agent to act, but
under the following slightly differing conditions according as I wish to obtain
merely acetic acid or else acetic acid and oxalic acid.
In the former case I prefer to use wood treated as just above described; I submit
it to the action of the oxydizing agent which may be either a current of hot air, or
a mixture of steam and air at a temperature of 110 to 130° C. (230 to 266° F.).
A product is thus obtained which when treated with water desintegrates completely,
the acetic acid remaining in solution in the form of alkaline acetate, and a residue
is got of wood pulp or cellulose which is not decomposed or encumbered with
impurities and which is suitable for paper stock.
If it be desired to obtain simultaneously acetic acid and oxalic acid, a mixture of
steam and air is used as the oxydizing agent but at a higher temperature up to
140° C. (284° F.) the fibre of the wood is then strongly attacked and the product
obtained, treated with water dissolves almost entirely leaving only a slight residuum.
The solution contains acetic acid together with a material quantity of oxalic acid.
The acids may be eliminated by the ordinary processes.
The mosses decompose more easily than the wood and are particularly suitable
for obtaining a large proportion of oxalic acid. If, after first soaking the moss in
boiling alkaline lye, it is exposed to the action of a current of steam and super-
heated air it will be decomposed and at a temperature of 110° C. (230° F.) and'
upwards give off oxalic acid together with acetic acid; the increase in temperature
will only accelerate the re-action and vary to a certain degree the proportions of
the two acids formed.
The strength of the alkaline lyes may vary within wide limits. But as it is
necessary to bring the mass to a temperature of about 250° C. (482° F.) there will
in the case of weak lyes be a loss of time because of the necessity for evaporating a
considerable quantity of water before the desired temperature is attained. As
I

page_text: furthermore an excess of bydrate does no harm to the result of the reaction it is
always preferable to employ very concentrated lyes.
It is not necessary that the treatment of the body to be oxydized with the caustic
lye should be done by heat but it is indispensable that the said body should be as
perfectly impregnated with the lye as possible. For spongy bodies such as moss
the latter may be sprinkled with the lye little by little while alternately compress-
For very
ing the moss and letting it expand; it sucks the liquid like a sponge.
compact bodies such as wood the chips may be soaked in cold lye but the penetra-
tion is then slow, while by using hot lye or by boiling the chips some moments in
the lye the process is accelerated.
The duration of the oxydation varies within wide limits according to the body
treated and the end in view. When moss for instance which has been made to
absorb concentrated lye and contains about 2 or 3 times its weight of the alkaline
hydrate, is exposed to the action of a mixture of air and steam at about 120° C.
(248° F.) it oxydizes very slowly and it takes 70 to 80 hours. There are then
formed carbon dioxide and acetic acid in notable quantities while only traces of
oxalic acid are found. When on the contrary raising the temperature of the
medium and increasing the proportion of the air in the mixture of the steam
and the air there will be found a progressive decrease in the quantities of acetic
acid and increase in the proportion of oxalic acid so that when operating towards
300° C. (572° F.) and with air alone without admixture of steam, the formation of
acetic acid ceases almost entirely and is replaced by oxalic acid. The duration
necessary for oxydation in this case would only be 2 or 3 hours.
If wood is operated upon the wood chips may be exposed to the caustic lye under
a current of air of 105 to 110° C. (213 to 230° F.) during 3 to 9 hours. After that
time the incrusting matter in the wood has become soluble in the water and contains
notable quantities of carbon dioxide and acetic acid and only traces of oxalic acid
while the fibre is disintegrated without being sensibly attacked that is to say it has
been transformed into paper pulp.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that
what claim is :
The process berein before described consisting in impregnating materials rich in
hydrates of carbon, especially wood and moss, with alkaline lyes and then treating
same with heat and an oxydizing agent for the purpose of producing acetic acid and
oxalic acid all according to the heat employed with the oxydizing agent and also
paper pulp as a useful residuum substantially as described:
Dated this 28th day of August 1894
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.