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Патент USA US2107527

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Patented Fch. 8, 1938
42,107,527 L
, l
‘. UNITED STATES
PATENT orrlcs
amass:
.
‘
PROCESS Foa oolxgliigg'nnmc oncmo
Theodore
and Karl R. Edlund,
Berkeley,Evans,
Calif.,Oakland,
assi
ment Company, San gnors to Shell Develop
poration of Delaware
Francisco, Calif..
a cor
No Drawing. Application
Novcmber 21, 1933,
Serial No.'699,032
38
((ilc 260-122)
This invention relates to the processes for con
centrating various dilute ‘organic acids and is
particularly concerned with the methods in which
certain solvents are used for this purpose.
A number of processes are known for concen
esses, where chemical stability, a relatively high
volatility. good acid, dissolving properties, and a
low solubility in water, are required from the
solvent.
In our co-pending application Serial No. 5
547,784, ?led June 29, 1931, we have described a
novel method for preparing mixed tertiary
ethers.
10 solvent systems from which concentrated acids
While our solvents can be used for concen
trating a large number of the organic carboxylic l0
acids, the advantages of using mixed ethers for
15 acid to be concentrated. Upon settling the dilute
the acid-solvent layer and the. water
layer. The acid-solvent phase, containing also
some water, is withdrawn and the solvent and
20 water are separated from the acid by distilla
01' said solvents, without the extraction step. In
practice, it is preferable, although not always
necessary, to employ solvents having boiling
tinuous operation.
30
ethers were the same in all cases.
Ether used
; quantities of
35
Percent
acid e?iciency
Relative
removal
40 ondary and tertiary ethers, such as methyl
Methyl tertiary butyl ................. _.
Methyl tertiary amyi. _
Methyl sec. butyl ____ __
Isopropy] __________ ..
Diethyl ______________ -_- ............... -.
61. 5, 60.0
45. 6
100. 0 40
74. 6
44. 7
26. 0
52. 2, 52. 5
73. 6
42. 8
'
85. 5
45 methyl secondary isoamyl, ethyl secondary butyl,
ethyl secondary amyl, ethyl secondary isoamyl,
Thwe data demonstrate the superiority of 45
propyl secondary butyl, propyl secondary amyl, mixed ethers over di-isopropyl ether, but the
propyl secondary isoamyl, isopropyl secondary same is not indicated with regard to the diethyl
~ butyl, isopropyl secondary amyl, isopropyl sec
ether.. However, the recovery of concentrated
;0 ondary isoamyl, methyl
acid requires the step of distilling on’ the ether,
tiary butyl', methyl tertiary amyl, ethyl tertiary
amyl, and other mixed ethers are excellently
suited for use, singly or combined in the above
5 outlined or otherv organic acid ‘extraction proc
and it is in this stage of the process that the rel- 50
ative de?ciency oi’ diethyl ether is to be noted.
2 >
2,107,527
I
a methyl tertiary butyl ether extract of acetic
fully used as components of complex solvents
acid can be readilyidistilled to produce 90% or used for concentrating organic acids. For ex
better acetic acid, ia similar extract of ‘diethyl ' ample, these ethers can be used together with
ether'yieids only 60% acid. -
‘ other solvents, such as hydrocarbons (pentane, 5;
in carrying out our invention in practice we ‘hexane, light naphthas and the lilge) , and/or cer- 55
prefer to employ a continuous process, in which
esters, in order to produce solvents a?ording
a solvent comprising one or more of the mixed higher partition coefficients for the acid and hav
ethers mentioned above is passed through a ver- ing a lower solubility in water, as well as a lower
tical contact vessel in an upward iiiow counter- ' capacityto dissolve the ‘same, thus increasing the 3
10 currently to a stream of a dilute organic acid. e?lciency with which a dilute organic acid can be 10
In order to obtain a larger area of contact between
concentrated.
cur solvent into the contact vessel under more
centrated by ‘extraction with suitable solvents
the aqueous andzsolvent phases we may inject
‘
.
Often, the ' ilute aliphatic acids which are con
or less high pressure through a smallori?ce, or e contain certain quantities of mineral acids. It
15 accomplish the dispersion of the solvent by some * was found, that it is very desirable that these 15
- ether physical means. Finely divided glohules of mineral acids were thoroughly removed by neu
the solvent rise then through‘ the descending
tralization or precipitation from mixtures either
stream of the progressively deconcentrated acid,
extracting more and more acid as they ascend.
before or after ' adding. to them or extracting
them with mixed ethers, because mineral acids
20 On theother hand, if desirable, the solution to
.be extracted may be dispersed throughout the
promote the decomposition of such ethers par- 20
ticularly at distillation temperatures. However,
solventiin a similar manner, the solvent now be-
if a niiineral acid is left in a mixture to be dis
coming the continuous phase.
tilled, we found, that'by adding an excess oi a
.
-
As a result of a sumcient contact of the twc
2&- phases and due to the solubility characteristics
~ of the materials used in the process, the acid dis-,-
known neutralizing agent or precipitant forsuch
an acid to the distilling mixture, the e?ect of acid 25
uponimixed ethers is effectively eliminated. For
tributes itself according to its partition coe?icient between the water and the solvent phases.
In this manner the acid content of the water
30 phase can- be reduced to any desired low value by
regulating the. operating conditions and the relative quantityeof the solvent used in the process.
The liquid continuously ?owing from the top
example, effective quantitiesc-i BaCoa or Bar-(OH):
or Ba(OOCCH3)z (sjolid or in solution) may be
used to suppress the eiiect cf the sulfuric acid
present in amixturerfrom which a mixed ether is 80
of the contact vessel consists essentially of the
:35 solvent and the extracted acid, and fountains a.
to be removed by distillation; AgOOCCHs may
be employed. in the case of hydrochloric acid.
It is obvious that a large number of the precess
steps and conditions (temperatures, pressures,
relatively small quantity of water, which isquite
be conceived for concentrating the individual or
insoluble in our solvents. . .;
This acid extract is subjected to a fractional
mixed dilute organic. acidsfin practice by using
our invention.
do not intend, however, to
distillation, the acid being produced as the dis40 tillation residue. The vaporized solvent and
limit our elaims to’ any speci?c method for prac
tising thesam'e, but believe any method or proc- in
steam are condensed into an acid-free conden-
ess, either batch or continuous, adapted for con
Satc. and. being substantially immiScib1c,.$eP4
centrating dilute organic acids and comprising
' arate into two phases. At ordinary temperatures
the step of treating Said acids Witré a, mixed ether
the condensed ~solvent contains onlygavery. small
45 quantity of'water and can be. immediately re'
.
and concentrations) and their combinations can as
cycled through the process‘
in any manner whatsoever, to 339 within the
Scope of our invention
45
We. claim as our invention:
In certain cases it is possible to accomplish conL The process for (iohcentmtmg an aqueous
carboxylic acid which comprises subjecting said
centration of a relatively dilute aliphatic acid by
acid to :selective extraction with an agent essen
simply adding to it a quantity of a mixed ether ;tially
comprising at least one mixed aliphatic
50 or a solvent containing such an ether, and then
distilling on the solvent and water from the mix lether.
2. Theprocess for concentrating anaqueous
ture, thereby producing the acid of a higher con
lower aliphatic carboxylic acid which comprises
centratiori than the original relatively dilute acid.
We have'iound that this method of operation
55 serves particularly well when the acid to be con
centrated is not very dilute but its concentration
is near the critical point, i. e. the point when the
- dilute acid becomes miscible with the selected
60
subjecting said acid tmselective extraction with
'arragent essentially comprising at least one mixed
aliphatic ether.
3. The process for concentrating aqueous acetic
acid winch comprises subjecting the aqueous
I
_
7
From {3111. observations of the processes
employ; acetic. acid_to .selective
extraction with an agent
6
solvent at a given temperature.
ing various solvents we have reached a:conclu-i es§entiauy comprising .at least. 039 mlxed
sion that mixed ethers' are often far superior toe
aliphatic ether.
:
I‘
the solvents previously used fer concentrating
4- The process for ccnccntlfating an aqueous
organic acids, so that it is possible to produce a’ carbcxylic acid which comprises subjecting the
t5 quantity of the concentrated acetic acid from‘ 9. aqueous acid to selective extraction with an agent i
> 'dilute acid by using far less of a-mixed ether, ' essentially gompl'isi?g at least
than would be? required of diethyl or isopropyl aliphatic tertiary ether.
:
.
one
’
mixed
ether, ior example, for producing the same yield
-5-':?I'he process for concentrating an aqllcclls
of thegzoncentrated acid. The greater emciency
carbcxylic acid which comprises subjecting the
7s of the new process appears to result from the
higher selectivity of the new solvents with re-
aqueous acid to selective extraction with an agent
essentially comprising at least one mixed aliphatic
gard to the components of an aliphatic acid-
ether possessing a butyl radical linked to the
water
We system.
have also discovered
that
'3
mixed 'ethers,
ethereal
6. The oxygen
process atom.
fr-r concentratingan aqueous
75 such as mentioned hereinbefore, can be success-
carboxylicéacid which comprises subjecting the
2,167,527
aqueous acid to selective extraction with an agent
‘ essentially
comprising
at
least
3.
taining a mineral acid, the step of subjecting said
acid so
one‘ mixed
aliphatic ether possessing a tertiary amyl radical
linked to the ethereal
'
'
7. In a
_izing agent insu?icient in amount to substan
tially neutralize the organic carboxylic acid.
acidis sulphuric acid and the neutralizing agent
acid.
is a barium compound.
20. In a process for concentrating an organic
-
8. The process of claim 7 wherein an aqueous
aliphatic acid is treated.-
10
'
-.9. The process of claim 7 wherein the solvent '
employed
nially fluid hydrocarbon.
'
10. In a process for concentrating an organic
carboxylic acid
'
aliphatic ether.
21. The process for continuously separating 15
water from its solution with acetic acid, in which
the dilute acid‘ is extracted with ethyl tertiary
'20
20
11.‘ The process of claim
25
aliphatic acid is treated. 10 wherein an aqueous
12. In a continuous
acid discharged in a concentrated condition from 25
‘
22. ‘The
the column base.
streams of the solution and a solvent essentially
thereby ex~
tracting the acid from its aqueous solution, con
30
and‘subjecting the
. rate the concentrated acid from the solvent and
will er .
,which the ether removes the
‘water in an azeotropic distillation and the formic '
acid discharged in a concentrated condition from
the column base.
\
23..In' the process of dehydrating aqu'eouss'oe I
40
lutionsof one or more of the lower fatty acids,
the use of mixed ethers haying normal boiling
points between 80° C. and 105° C. for extracting
the acid or acids from the water.
4-5
densing the vaporized solvent and Watenthereby
producing a non-miscible solvent-water system,
and continuously returning the condensed solvent
'
distillation in the presence of a’ mixed'ether hav
ing a normal boiling point between 80° C. and
. to the process’.
105° C., said ether acting as a withdrawing-agent
forthe water.
14. In a process for concentrating an organic
~
‘
25. The process for continuously separating
carboxylic acid from its aqueous solution, a step
of subjecting said acid solution to a fractional
distillation in the presence 01' a solvent essentially
trating the acid. -\
'
24. The process 01" dehydrating aqueous solu- I
tions of one or more of the lower fatty acids by
‘solution with‘ one or
C‘)
the aqueous layer discharged after
complete exhaustion, the ether layer, containing
‘
15. In a process for the'recovery of an organic
carboxylic acid from its aqueous
in an azeotropic distillation and the lower fatty‘
resultant solution the solvent and water.
16. In a process-for concentrating acetic acid
from. its aqueous solution, the steps of extracting
acid or acids are discharged in a concentrated
condition.
'
-
26._The process, for separating water from a
the‘ acid from its aqueous solution with a solvent
mixture with one or more of the lower fatty
essentially comprising a mixedgaliphatic ether
acids by distillation with
‘
and removing the concentrated acid from the ex
tract by tractional distillation.
‘ 1'7. Ina process Iorconcentrating a relatively. . '
dilute acetic acid, a step comprising subjecting‘
said acid to a fractional distillation in the pres-'
ence ofla solvent essentially comprising a mixed
aliphatic ether, thereby evaporating. the solvent
and the water' and concentrating the ‘acid.
18. ' n a process for concentrating an organic‘
carboxylic acid _from its aqueous solution con-i
water layer discharged, the ether layer returned
to the still head to remove more water, and the 70
process conducted
fatty acid or acids.
‘
so as to . giveconcentrated
27. In the process of dehydrating aqueous
acetic acid, the use 01' mixed ethers having nor
75
9,107,527
. ,
34. The process for ' separating water from’
formic acid by distillation with methyl tertiary
amyl ether in which the water and ether forms
mal boiling points between 80 and 105° C. for
extracting the acetic acid from the water.
an azeotropic mixture in the still head, the vapor
28. Theproce'ss oi dehydrating aqueous acetic
acid by distillation in the presence of a mixed
ether having a normal boiling point between 80
and 105° C., said ether acting as a withdrawing
ous azeotropic mixture condensed, the condensate .
separated into a water and an ether layer, the
.
water layer discharged, the ether layer returned
to the still head to remove more water, and the
process conducted so as to give concentrated 10
agent for the water. '
29. The process for continuously separating
water from its solution with acetic acid, in
which the dilute acid is extracted with a mixed
10 etherhaving a normal boiling point between 80
and 105° C., the aqueous layer discharged after
substantially complete exhaustion, the ether lay
er, containing substantially all of the acid origi
nally present and part of the water, passed to a
formic acid in the still pot.
35._ The process for continuously separating
water from its solution with butyric acid, in which
the dilute acid is extracted with-a mixed ether
having a normal boiling point between 80 and 15
105° C., the aqueous layer discharged after sub
stantially complete exhaustion, the ether layer,
15 column still in which the ether removes the water
containing substantially all oi the acid originally
present and part of the water,'passed tov a column
in an azeotropic distillation'and the acetic acid
discharged in a concentrated condition from the
still in which the ether removes the water in an 20
azeotropic distillation and the butyric acid dis
column base.
30. The process for separating water? from
20 acetic acid by distillation with a mixed ether
having a boiling point between 80 and 105° 0.,
in which the water and ether forms an azeo
tropic mixture in the still head, the vaporous
charged in a concentrated condition from the
column base.
azeotropic mixture condensed, the condensate
.25 separated into a water and an ether layer, the
‘
36. The processv for separating water
irom
butyric acid by distillation with a mixed ether 25
having a boiling point between 80 and 105° 0.,"
in which the water and ether forms an azeotropic
mixture in the still head, the vaporous azeotropic
water layer discharged, the ether layer returned
mixture condensed, the condensate separated into
to the still head to remove more water, and the
a water and an ether layer, the water layer dis
process conducted so as to give concentrated
charged, the ether layer returned to the still head
to remove more water, and the process conducted
so as to give concentrated butyric acid in the
acetic acidin the stillipot.
‘
31. The process for separating water from
actic acid by distillation with ethyl tertiary amyl
ether, in which the water and ether forms an
azeotropi'c mixture in the still head, the vaporous
azeotropic mixture condensed, the condensate
'
30
still pot.
s
37. The process
for continuously separating
a 35
substantial amount of the water present in its
solution'with one or more of the lower fatty acids
separated into a water and an ether layer, the
from said acid or acids, in which the dilute acid
water layer discharged, the ether layer returned
or acids is extracted with a'mixed ether having
to the still head .to remove more water, and the
conducted so as to give concentrated
process
a
acetic acid in the still pot.
'
~
32. The process for continuously separating
water from its solution with formic acid, in
,
dilute acid is extracted with a mixed
'
° C.,.
40
the aqueous layer
the ether layer, I
complete exhaustion,the acid or acids originally
substantially all of
and part of the water passed to a column ‘I
present
still in which the ether removes part but not all
or the water in an azeotropic distillation, and the
lower fatty acid or acids are discharged contain
the ether ing some or the water originally present.
' substantially - complete
38. The process for separating a substantial
layer, containing substantially all or the acid‘
originally present and part of the water, passed amount of the water in ,a mixture with one or
to a column still in'which the'ether removes the more or the lower fatty acids by distillation with
water in an azeotropic distillation and the formic a mixed ether having a normal boiling point be
ether having a ‘normal boiling point between 80
and 105° C_., the aqueous layer discharged after
tween _80° and 105° 0., in which the water and
other forms an azeotropic- mixture in the still
33. The process for -. separating water from head, the vaporous azeotropic mixture is con
formic acid by distillation with a mixed ether 3 densed, the condensate separated into a water
having a boiling point between 80 and 105°'C., and an other layer, the water layer discharged,
acid discharged in a concentrated condition from
the column base.
-
'
' in which the water and ether forms an azeotropic - the ether layer return
_
the vaporous 'azeotropic
to the still head to re
move more water, and the process conducted'so
mixture condensed, the condensate
separated into as to give fatty acid or acids still containing some
the water layer dis-v
a water and an ether layer,
THEODORE EVANS.
charged, the ether layer returned to the still head
water.
to remove more water, and the process conducted
so as to give concen
still pot.
I
formic acid in vthe
'
-
.
'
KARL' a. EDLUND.
'
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