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.Oct. 15, ‘1946.
2,409,441 '
Filed Ilay '1, 194:
1 4%,,”
Patented Oct. 15, 1946
Floyd J. Metzger, New York, N. Y., assignor, by
mesne assignments, to U. S. Industrial Chemi
cals, Inc., New York, N. Y., a corporation of
‘' Application May 7, 1943, Serial No. 486,057
3 Claims. (Cl. 260-635)
This invention relates to the recovery of glycols
from solutions resulting from the hydration of
aqueous solutions of ole?n oxides in the presence
of an acid catalyst and particularly to the elimi
nation of complex compounds of the glycol with
the acid which are formed during the hydration.
As an example of the application of the in
vention, it will be described with reference to the
production of ethylene glycol by hydration of
pipes and valves and by depositing on heating
coils may interiere with the transfer 01 heat.
Frequent shut-downs are required to remove the
salt, and filtration is necessary to separate the
salt from the glycol. Complete separation is
never possible, and some loss of glycol results.
The various operations and losses add to the op
erating cost.
It is the object of the present invention to avoid
ethylene oxide as set forth in the patent to 10 the di?iculties mentioned and to afford a simple,
Frederick R. Balcar No. 2,135,271. The same
procedure may be utilized, however, in the pro
duction of other glycols.
In the Balcar procedure, ethylene oxide is dis
e?lcient and economical procedure whereby the
glycol can be recovered without resort to the
complicated treatment hereinbefore described.
Another object of the invention is the provision
solved in water containing an acid hydration 15 of a satisfactory procedure whereby both free acid
and combined acid are easily separated from the
glycol solution, which may be evaporated and dis
tion. The solution is subjected to heating for a
tilled, if necessary, without the disadvantage of
period of about thirty minutes at a sulliciently
salt deposits during the operation.
catalyst, preferably sulphuric acid in the pro
portion of about 1/2% of the weight of .the solu
elevated temperature to convert the ethylene 20 Other objects and advantages of the invention
oxide to ethylene glycol. A temperature of about
will be apparent as it is better understood by
30°~40° C. is usually employed.
reference to the following speci?cation and ac
The continuous production of ethylene glycol
companying drawing, which illustrates diagram
by the procedure described produces an aqueous
matically an apparatus suitable for the practice
solution of glycol containing the acid used as 25 of the invention.
the catalyst. The solution is continuously with
I have discovered that the complex compound
drawn from the conversion chamber. The re
of glycol with an acid, which is produced during
covery of the glycol from the solution presents
the hydration of aqueous solutions of an ole?n
considerable di?iculty. Some of the acid catalyst
oxide and is not amenable to simple neutraliza
is present as such in the solution. The re 30 tion with an alkali, can be broken down and that
mainder is combined in some manner, not fully
the acid thus released can be separated, together
known, with the glycol. It cannot be titrated as
with free acid originally present, by the simple
free acid and is not precipitated by the addition
procedure hereinafter described‘. The desired re
of barium chloride.
sult is accomplished by subjecting the glycol solu
Owing to the presence of the combined acid, it . .1 tion to an anion adsorbing resin of which several
has been necessary to follow a complicated and
types are available. Such resins have been used
expensive method to remove the acid from the
heretofore to separate free acids from solutions,
glycol solution. This involves treating the solu
but it has not been known that the combina
tion with an excess of caustic soda and heating
tion of glycol with an acid in the form herein
at an elevated temperature for a considerable 40 described is amenable to the anion adsorption
period. Thereafter, the excess alkali must be
neutralized with additional acid. The consump
tion of alkali and acid is considerable.
The solution, then containing sodium sulphate,
activity of resins..
In carrying out the invention, I may use any
resin of the anion adsorption type. Several are
known, and it will su?lce to mention two which
is evaporated in a triple-e?ect evaporator to re 45 are commercially available. These resins are in
move the water in stages and is ?nally treated
general the product of condensation of organic
in a vacuum distillation apparatus to vaporize
amines or similar basic materials with formalde
and recondense the glycol. As evaporation pro
hyde. One known as “Anex” is believed to be a
ceeds, the concentration of sodium sulphate in
melamine resin, since it contains about 33% of
creases to the limit of solubility, after which it 50 nitrogen. The other, “Amberlite 1R-4” is the
precipitates as solid sodium sulphate. The salt
product‘of condensation of aromatic amines such
is deposited in increasing amounts in the latter
as aniline with formaldehyde. The invention is
stages of evaporation, and ?nally in the vacuum
not limited to the use of these particular prod
distillation equipment. This, of course, is un
ucts, as any resin having anion adsorption activ
desirable because it may result in stoppage of 55 ity can be used to accomplish the purpose.
For the purpose of the invention, a simple ap
paratus may be used. It may consist of a col
umn 5 in which a deep bed 8 of the resin is sup
ported. The resin may be in the form of par
ticles ranging in size from 16 to 50 mesh, al
though larger or smaller particles may be used.
A pipe 1 is connected to the bottom of the col
umn to permit the introduction of the glycol s0
luticn which escapes through a pipe 9 at the top.
Suitable connections i0 and H may be provided
_ to permit the introduction of water and the re
The procedure avoids much of the expense
heretofore incident to the recovery of glycol from
solutions in which it is formed by catalytic hy
It is'simple and more efficient, involv
ing only the use of inexpensive equipment.
Various changes may be made in the appa
ratus without departing from the invention or
sacrificing. the advantages thereof.
‘ I claim:
1. The method of converting an ole?n oxide
to the corresponding glycol, which comprises dis
solving the ole?n oxide in water containing an
acid hydration catalyst that forms a non-titrat
generation solution when necessary.
‘The glycol solution is introduced and caused
to flow through the bed of resin at a. relatively
able acid complex with the'glycol, maintaining
low rate such that when the solution leaves the 15 the resulting solution under conditions favorable
apparatus it will contain no free or combined
for hydration of the dissolved olefin oxide to the
acid. Operation is preferably at normal room
corresponding glycol, and subsequently treating
temperature, 1. e., 70° F., although the tempera
the glycol solution with an anion adsorbing resin
ture is not critical except with reference to ele
to break down the glycol-acid complex with lib
vated temperatures. When the resin has lost its 20 eration of the'acid and to remove the free acid
adsorption power as shown by the appearance of
from the solution.
acid in the eiiluent, it may be regenerated by
2. The method of liberating the acid from the
?rst ?ushing the bed with water to eliminate the
non-titratable glycol-acid complex formed dur
glycol solution and then introducing an aqueous
ing the hydration of an aqueous solution of the
solution of sodium carbonate, preferably 2%-4% 25 corresponding ole?n oxide in the presence of an
by weight. The resin‘ is then rinsed with water
acid hydration catalyst that forms such a com
and is ready _for further use.
plex with the glycol and removing the free acid
The glycol solution, free from acid, and par
from the resulting glycol solution, which com
ticularly acid'in combination with the glycol, may
prises passing the aqueous glycol solution through
be delivered to the multiple eifect evaporator and, 30 a bed of anion adsorbing resin.
after concentration, may be distilled to recover
3. The method of liberating sulphuric acid
the glycol. Since no alkali is introduced, the so
from the non-titratable ethylene glycol-sulphuric
lution is free from sodium sulphate and conse
acid complex present in the aqueous solution requently no di?iculty is met with deposits in the
sulting from the hydration of ethylene oxide in
evaporating and distillation system. Moreover, 35 the presence of sulphuric acid, which comprises
since the solution is free from acid and salt, a
passing the aqueous solution of ethylene glycol
marketable glycol may be obtained merely by
through a bed of an anion adsorbing resin.
evaporation and without the necessary step of
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