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Aug. 8, 1961
J. K. FARRELL
2,995,424
HYDROGEN PEROXIDE VIA TETRAHYDROANTHRAQUINONE
Filed Oct. 6, 1958
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INVENTOR
JAMES K. FARRELL
ATTORNEY
United States Patent
j Ce,
2,995,424
Patented Aug. 8, 1961
2
l
eñìcient method ofy producing hydrogen peroxide via
alkylated anthraquinones in which the- working solution
..
'
2,995,424
f
contains substantial amounts of tetrahydroquinone com
HYDROGEN P_EROXIDE VIA TETRAHYDRO
.
ANTHRAQUINONE
‘_ ’
.
James K. Farrell, Syracuse, N.Y., assiguor to Allred GI
pound.
v
-
ChemicalCorporatiou, New York, N. ., a corporation
Another object of the present invention is to provide
a method of maintaining high productivity of hydrogen
of New York
peroxide in a process for the production of hydrogen per
y
.
i
'
Filed Oct. 6, 1958, Ser. No. 765,367 „
10 Claims.
(Cl. 23-207)
v
I
This invention relates to the production of hydrogen
peroxide and more particularly refers- to a new and n_m
proved process for the production of hydrogen peroxide
oxide via alkylated anthraquinones in which nuclear hy
drogenation
A further object of the present invention is to provide
an efficient method of producing hydrogen peroxide in a
cyclic process involving hydrogenation of mixtures con
by a cyclic operation involving the reduction of a quinone
taining an alkylated tetrahydroquinone compound dis
compound, oxidation of the hydroquinone compound
produced, »and separation of the thus formed hydrogen
sulting tetrahydroanthraquinone dissolved in the water
peroxide.
.
l
The anthraquinone process for the production of _hy
drogen peroxide as commercially practiced and described
in the literature is a cyclic operation in which an anthra
solved in a water-immiscible solvent, oxidation of the re
7
` ible solvent, and water extraction of the hydrogen
peroxide formed during oxidation. Other-_.> objects and
advantages of the invention will be apparent from the
following description and accompanying drawing.
quinone compound dissolved in a water-immiscible sol 20 In accordance with the present invention hydrogen
peroxide is continuously produced by a cyclic process in
presence
vent is hydrogenated
of a catalyst,
to athe
hydroquinone
hydroquinonc
compound
compound
in 1s
volving hydrogenating a working solution containing an
alkylated tetrahydroanthraquinone dissolved> in a water
oxidized to the quinone compound with formation of hy
immiscible solvent to convert the alkylated tctrahydro
drogen peroxide, and the hydrogen peroxide formed dur
ing the oxidation extracted with water. In the hydrogena 25 anthraquinone to the alkylated tetrahydroanthrahydro
quinone, subjecting the hydrogenated working solution to
tion of the anthraquinone compound to the correspond
oxidation in the presence of a small amount, within the
ing hydroquinone one of the side reactions leads to the
range of about 0.002% to about 0.25%, preferably
addition of hydrogen to the aromatic nucleus of the an
0.005% to 0.02%, by weight of a. water-soluble ionizable
thraquinone compound forming the tetrahydroanthra
quinone compound. In the course of repeated cyclic op 30 inorganic alkaline compound with elemental oxygen in
the form of pure oxygen or a gas containing elemental
erations the anthraquinone compound becomes converted
oxygen to produce alkylated tetrahydroanthraquinone
to the tetrahydroanthraquinone compound to an extent
and hydrogen peroxide and extracting hydrogen peroxide
of sixty or more percent of the original anthraquinone
from said oxidized solution by passing the oxidized solu
compound. The formation of tetrahydroquinone in the
tion in intimate contact with water.
arithraquinone process for the production of hydrogen
In a more speciiìc embodiment of the invention a work
peroxide has been objectionable because it is four to six
ing solution comprising an alkylated anthraquinone such
times as dillicult to oxidize as the corresponding anthra
as methyl-, ethyl-, propyl-, iso-butyl-, dissolved in a
quinone compound. The elîect of the presence of sub
mixed solvent of two or more constituents consisting of
stantial quantities of tetrahydroquinone compound in the
a constituent capable of dissolving the quinone form such
working solution is to seriously reduce the capacity lof
as an aromatic hydrocarbon,- e.g. benzene, toluene and
the plant for producing hydrogen peroxide and may mean
xylene, a constituent capable of dissolving the hydro
the difference between running the operation at a loss or
profit. The art recognized the problem of tetrahydro
anthraquinone formation in the hydrogen peroxide proc
quinone form such as an alcohol having from 5 to 12
carbon atoms in the molecule as for example amyl alco
ess yand considerable work has been done in an attempt
hol, cyclohexanol, methyl cyclohexanol, octyl alcohol,
to minimize this inherent difficulty. One suggestion, U.S.
Patent 2,673,140, was to limit the degree of hydrogena
such as, a ketone, e.g. acetophenone, is in 'a continuous
nonyl alcohol and decyl alcohol, and a synergistic solvent
cyclic operation subjected to hydrogcnation in the pres
tion to a level of about 60% instead of 100% by main
ence of a palladium catalyst to convert the anthra
taining the hydrogen gas partial pressure to 0.9 atmos
phere or less. Obviously, such procedure reduces the po 50 quinone to the hydroquinone with concomitant formation
as a side reaction of tetrahydroanthraquinone resulting
tential hydrogenation capacity. Furthermore, even at re
from the addition of hydrogen to the aromatic nucleus
duced hydrogenation levels tetrahydroanthraquinone con
tinues to form at a measurable rate and accumulates in
of the anthraquinone, subjecting the hydrogenated Worr'k
the system.
ing solution to oxidation in the presence of a small
reduction inthe rate of tetrahydroquinone can be thus
gen to convert the anthrahydroquinones to the corre
Rosenmunde and co-workers found that
some degree of control of catalyst activity to reduce ring 55 amount, within the range of 0.005% to 0.02% by weight
of sodium hydroxide or ammonium hydroxide, prefera
hydrogenation could be obtained by the use of amines.
bly ammonium hydroxide, with elemental oxygen in the
Similar claims, U.S. Patents 2,720,531 and 2,720,532 are
form of pure oxygen or a gas containing elemental oxy
made for organic nitrites and nitriles. Although some
effected, the forrnationis not prevented and it continues
to be a serious problem. In another method as described
in U.S. Patent 2,739,042 the working solution containing
tetrahydroquinone was given a special separate catalytic
treatment to convert it Ito the corresponding anthra
quinone. While this method was successful in maintain
ing the capacity of the hydrogen peroxide process never- I
theless it entailed considerable cost for treating and con
verting the tctrahydroquinone. n
y
‘
An object of the present invention is to provide a more
sponding anthraquinones `and produce hydrogen peroxide,
adding a small amount of acid to the oxidized working
solution in an amount about equal to or greater than the
amount of oxidation catalyst, generally within the range
of 0.002% to 0.5% by weight, and extracting hydrogen
peroxide from said oxidized solution by passing the oxi
dized solution in intimate contact with water, and re
cycling the resultant working solution for further hy
drogenation.
Basic chemicalreactionsintheprocess fortheprcduc
2,995,424
3
tion of hydrogen peroxide via an
is illus
Theartsought-to overoomethisdiñìculty inhcreminthe
trated by the following equations:
(1)
anthraqt?none process for the production of hydrogen
peroxide by attempting to slow down the formation of
o
5
01H5
tetrahydroanthraquinone by proces control, as for ex
ample, by operating the hydrogenation step at a reduced
level, i.e. hydrogenating only about 60% of the anthraquinone compound.
\
The present invention is based on a new and different
+B:
approach-_the utilization of the tetrahydroquinone com
EA Q
(2-ethy1anthraquinone) \
l0 pound as an active working constituent for production of
EHQ
(Z-ethylanthrahydroquinone)
(|)H
CrHl
hydrogen peroxide without any attempt made to retard
the formation of tetrahydroanthraquinone or removal of
the tetrahydroanthraquinone. This is based on the dis
covery that the addition of relatively minute amounts of
15 oxidation catalyst within the range of 0.002% to 0.25 %,
preferably within the range of 0.005% to 0.02% based
on the weight of the working solution when added to the
working solution undergoing oxidation would surprising
ly increase the rate of oxidation of the tetrahydroanthra
Hr
20 hydroquinone compound four to six times, e.g. reduce the
time of oxidation from about 20-25 minutes to about 3-5
H
THH
(Q-ethyItetrah
anthra
hydroq none)
(2)
minutes. Quantities of such oxidation catalyst substan
tially in excess of 0.25% are not eEective for increasing
the rate of oxidation and usually act as an accelerator
25 to produce undesired by-products and causes decomposi
OH
tion of hydrogen peroxide with loss of the desired prod
uct. The oxidation catalysts of the present invention
when added to the working solution undergoing oxidation
tend to cause the formation of emulsions with the water
30 used for extracting the hydrogen peroxide from the oxi
dized working solution probably due to reaction with by
products to form surface active materials. The addition
EAQ
of an acid in an amount equal to or greater than the
amount of oxidation catalyst has been found to overcome
the tendency to emulsify and the hydrogen peroxide may
be readily extracted from the oxidized working solution
with water without ditliculty of emulsiñcation.
The oxidation catalysts of the present invention are
ionizable water-soluble compounds having an alkaline
40 reaction. I have found that there is direct relation be
-tween the degree of water solubility `and the catalytic ef
fectiveness of the alkaline compound employed; the more
water soluble it is, the more effective it becomes as an
oxidation catalyst. While the mechanism of the catalysis
ClHl
+1110! 45 is not known, it appears that water, and/or hydrogen
peroxide, is essential in one or more steps of the oxida
tion using alkaline catalysts.
8
THQ
Organic alkaline com
pounds are undesirable for many reasons, among which
are inetïectiveness as an oxidation catalyst compared to
As will be noted from Equation 1 above, hydrogenation 50 the water-soluble ionizable inorganic alkaline compounds
of anthraquinone in the presence of a palladium catalyst
of the present invention, ltend to contaminate the hydro
produces as a primary reaction anthrahydroquinone and
gen peroxide product and complicate purification and
as a side reaction a portion of the -anthraquinone is con
concentration of the hydrogen peroxide product, tend to
verted to the tetrahydroanthraquinone compound as well
reduce the life of the palladium catalyst, and are eco`
as a very small amount of non-peroxide producing by 55 nomically disadvantageous because they are more ex
products of unknown composition. As a practical matter
pensive than »the oxidation catalysts of the present in
the working solution must be recycled many times, usual
vention.
ly live hundred or more times, thus subjecting the anthra
- Examples of the oxidation catalysts are ammonium
quinone to an equivalent number of hydrogenations with
hydroxide, sodium hydroxide, potassium hydroxide, so
consequent formation of the corresponding tetrahydro 60 dium carbonate, calcium hydroxide and magnesium hy
anthraquinone in each cycle which accumulates in the
droxide. Although not preferred, barium and calcium
working system displacing the anthraquinone often to an
carbonates may be employed. The preferred oxidation
extent of sixty or more percent. y Although the tetrahy»
catalysts are the alkali metal hydroxides and ammonium
droanthraquinone formed in a side reaction during the
hydroxide. Of these hydroxides ammonium hydroxide
hydrogenation step may be used as a working compound 65 and sodium hydroxide appear to be best. Ammonium
in the hydrogen peroxide process, unfortunately the
hydroxide is superior to sodium hydroxide in that a
oxidation of the tetrahydroanthrahydroquinone proceeds
smaller quantity of ammonium hydroxide as compared to
at a rate of about one-fifth the rate at which the anthra
sodium hydroxide has been found to be effective as a
hydroquinone oxidizes. The oxidation of anthrahydro
catalyst and additionally, ammonium hydroxide being
quinone and tetrahydroanthrahydroquinone is illustrated 70 volatile can be more readily separated from the reaction
products.
in Equations 2 and 3 above. Merely as illustrative, oxi
dation of ethylan-thrahydroqninone will occur in about
The accompanying drawing diagrammatically illustrates
three to live minutes whereas oxidation of the corre
sponding ethyltetrahydroanthrahydroquinone, under the
one method of carrying out the invention.
A working solution is first prepared composed of a
same conditions, requires twenty to twenty-five minutes. 76 quinone compound dissolved in a solvent medium, pref
‘ 2,995,424
5
' 6
e’rablyy a mixed >solvent with three constituents consisting
of a constituent capable of dissolving the quinone such
`as Berl saddles or glass beads. A small amount, about
as an aromatic hydrocarbon,‘e.g.«xylene, a constituent
as ammonium hydroxide or sodium hydroxide may be
added to the working solution through line 10 or may be
0.005% to 0.02%, by weight of oxidation catalyst, such
capable `of dissolving the hydroquinone formed, such as
introduced directly into oxidation tower 14. The primary
an alcohol, e.g. octanol-Z,> and a lsynergistic solvent, e.g.
a ketone such as acetophenone.V 'I'he quinone compounds
used as the solute are anthraquinone and derivatives -of
reaction in'oxidation tower 14 is the oxidation of the
anthrahydroquinone compounds in the working solution
to the anthraquinone form with hydrogen'peroxide split
ting olf during the reaction. 'I‘he oxidation of the antha
and butyl-anthraquinones, the corresponding nuclear hy
drogenated anthraquínones and anthrahydroquinones. 10 hydroquinone compounds may be accomplished from be
low room temperature to about 40° C. or more, prefer
The mixture termed working solution is usually composed
ably about 25-35° C. Oxidation may be accomplished
of about 10-25% quinone compound, l10 to 60% ketone
at atmospheric pressure and preferably under superatmos
compound, with the balance made> up of the aromatic
pheric Apressure by passing an oxygen-containing gas,
hydrocarbon and alcohol solvents. An illustrative ex
ample illustrating the composition o_f a typical initial 15 4preferably air, by means of compressor 15 through line
16 intooxidation tower x14. The off-gases released from
working solution would ben15% Z-ethylanthraquinone,
anthraquinone such'as methyl-, ethyl-, propyl-, iso-, tert.-,
th tòp of oxidation tower 14 through line 17 and valve
20% xylene, 40% acetophenone and 25% octanol-2s.
During the course of operation by reduction and oxida
18 consist principally of nitrogen and usually contain less
tion to produce hydrogen peroxide nuclear hydrogena-.
than 1% oxygen.` The oxidation catalyst effects more
complete and rapid utilization of the oxygen in the air
thereby effecting a saving in `the: amount of oxygen-con
taining gas used and also producing a substantially» pure
tion occurs as a side reaction and after repeated cyclic
operations the tetrahydroquinone formed will increase
withcorresponding decrease ofthe anthraquinone formed
nitrogen which may be used in the plant for blanketing
in the working solution until after repeated cyclic opera
tionsV sixty or morejpercent of the anthraquinone com
pound 'initially present in the working solution will be 25 The products of the oxidation reaction Withdrawn
converted to the tetrahydroanthraquinone form. If de
from the bottomof oxidation tower 14,through line
19 containing about 1.5% hydrogen peroxide are then
sired the‘initial working solution may contain a mixture
subjected to water extraction .to separate the hydrogen
of anthraquinone and tetrahydroquinone compounds ’or
purposes.
may contain only tetrahydroquinone compound as a
>quinone constituent. 'I‘he working solution in the cyclic
30
operation will, after hydrogenation, contain vthe quinone
compound predominantly or entirely in the anthrahydro
quinone form and after the oxidation reaction the quinone
compound will be predominantly or entirely inthe anthra
quinone form.
35
`
'
`
I
"
’
jperoxide from the working solution. “It was found that
the presence of `the oxidation catalyst ltends to form
emulsions when extracting the hydrogen peroxide with
water from the working solution making the extraction
operation diñìcult particularly on a large> scale commer
cial operation. To negate the lemulsion for-ming tend
ency of the oxidation catalyst a mineral acid> such as
ofv about 20'-50° C. under substantially-atmospheric pres-`
sulfuric acid or phosphoric acid is added through line 21
to -the working solution. In practice it has been'found
that the amount of acid required is small, usually an
sure of about 1-5 p.s.i.g. To the working solutionis
amount by weight equal to and up to three to four times
._ l"lfhevworking solution is introduced through line ~1 in
a reducingchamber 2 maintained in a temperature range
added, through line 1, hydrogenation catalyst such as 40 the amount of oxidation catalyst will be adequate or
stated in terms of percentage an amountof acid based
palladium or platinum, preferably palladium, disposed on
on the weight of working solution of about 0.002% to
a solid-support. The preferred catalyst consists of about
5% palladium on a charcoal or'- alumina'carrier.
The
about 0.5%. Reaction products from line 16 are fed
to centrifugal extractor 22 into which distilled water
amount of catalyst required is approximately 1-~10% by
weight of the quinone present. -Hydrogen is forced by 45 through vline 23 in contact with working solution result
ing in a water solution containing about 10-20% dis
pumpß through' line 4 into the bottom of reducing cham
solved hydrogen peroxide together with small amounts
ber 2 in intimate contact with a body of working solu
of impurities which are withdrawn from extractor 22
tion containing suspended catalyst. Sufficient agitation
through line 24 and may, if a purer and more concen
t'o produce the necessary interfacial area for reasonable
reaction‘rat'e and to maintain necessary suspension of 50 trated solution is required, be subjected to further p_uri
catalyst is supplied by circulation of the hydrogen gas
`'stream which is released from the top of chamber 2
through line 5 to the suction side of compressor 3. The
hydrogen necessary tofsustain the reaction is added to
?ication and fractionation. Working solution removed
from extractor 22 through line 25 is recycled to reducer
2 via line 26. Make-up solution may be added from
time -to.time `through line 27 to replace that lost from
l
the circulating stream of hydrogen via line 6. The- hy 55 mechanical losses and chemical degradation.
4 The following examples illustrate the‘present invention.
drogenation reaction may be `carried to a high level ap
proaching or at the level of 100% thus enhancing the
Example 1
etliciency of the operation. Previously care had to bel
A
working
solution
comprising
a mixed solvent in the
taken to avoid exceeding a level of about 60% hydro
genation in order to minimize nuclear hydrogenation.y 60 proportion of 34.1 parts by weight acetophenone, 27.1
parts by weight capryl alcohol, and 23.7 parts by weight
In the present invention nuclear hydrogenated quinone
xylene and containing as a solute 15.1% by weight of a
vcompounds are no, longer a handicap to the production
mixture of 2-ethyltetrahydroanthraquinone and 2-ethylof ’hydrogen peroxide and therefore the hydrogenation
anthraquinone of which the tetrahydroanthraquinone con
reaction'may be carried out Ito its full potentialities. '
VThe hydrogenated' solution containing suspended cata 65 stituted 61% of the total ethyltetrahydroanthraquinone
lyst is discharged f_rom‘reducer 2‘ throughl line 7 into
centrifuge 8 wherein the catalyst'is separated from the
solution and‘returned via line 9 to reducing chamber 2.
and ethylanthraquinone was subjected to repeated cyclic
operations each cycle involving hydrogenation of the
working solution, oxidation of the working solution, and
extraction with water of the hydrogen peroxide from the
fuge 8 flows through line 11 into after-cooler 12 wherein 70 oxidized lworking solution. The hydrogenation reaction
The working solution, after removal of catalyst in centri
some vof the exothermic heat ot reaction resulting from
the hydrogenation is removed by indirect heat exchange
with cooling water and the cooled solution introduced
is Vcarried "out by passing hydrogen through the working
solution containing 0.5% catalyst consisting of 5%'pal
ladium deposited on carbon carrier at a temperature of
25° C. until 1200 volumes'of hydrogen per 100 volumes
through line 13 into the top' of oxidation ltower 1_4 which
desirably is a vertical column iìlled with packing such 75 'of working solution were absorbed.- The ‘catalyst was
2,995,424
8
7
then separated from the hydrogenated working solution
stituted 51% `of the total ethyltetrahydroanthraquinone
and ethylanthraquinone was subjected to repeated cyclic
operations each cycle involving hydrogenation of the
working solution, oxidation of the working solution, and
extraction with water ofzthe hydrogen peroxide from the
and the working solution then subjected to oxidation at
a temperature of 30° C. by passing air up through the
hydrogenated working solution until 1000 volumes of
oxygen per 100 volumes of working solution were _ab
sorbed by the working solution. The oxidized working
oxidized working solution. 'I'he hydrogenation reaction is
carried out by passing hydrogen through the working
solution containing 0.5% catalyst consisting of -5% pal
solution was then scrubbed with water to remove the
hydrogen peroxide product and the working solution
therli returned for further hydrogenation to start another
ladium deposited on carbon carrier at a temperature of
25° C. until 1400 volumes of hydrogen per 100 volumes
of working solution were absorbed. The catalyst was
cyc e.
In the above operation the time required for etïecting
oxidation of working solution in each cycle requires
20-27 minutes.
then separated from the hydrogenated working solution
and the working solution then subjected to oxidation at a
.
temperature of 30° C. by passing air up through the hy
In a series of comparative cycle operations in accordance with the practice~ of the present invention.__0.03 15 drogenated working solution until 1200 volumes> of oxygen
per 100 volumes of working solution were absorbed by the
part by weight of the working solution of sodium hy
droxide was added to the working solution and subjected
working solution. ~The oxidized working solution was
then scrubbed with water to remove the hydrogen peroxide
to oxidation. The time required for effecting the oxiproduct and the working solution then returned for fur
dation, i.e. absorbing 1000 volumes of oxygen per 100
volumes of working solution, was 4--5 minutes. To the 20 ther hydrogenation to start another cycle.
In the above operation the time requiredfor effecting
oxidized working solution was added 0.05% by 'weight
of working solution of sulfuric acid and hydrogen perox
oxidation of working solution in each cycle requires 16
ide was then extracted from the working solution with
water without any ditlìculty due to emulsiñcation.
minutes.
'
‘
In a series of compartive cyclic operations in accord
ance
with the practice of the present invention 0.01 part
25
Example 2
by weight of the working solution of ammonia was added
A working solution comprising a mixed solvent in the
to the working solution and subjected to oxidation. The
proportion of 27.4 parts by weight acetophenone, 28.7
time required for effecting the oxidation, i.e. absorbing
parts by weight capryl alcohol, and 27.0 parts by weight Y
1200 volumes of oxygen per 100 volumes of working
xylene and containing as a solute 16.9% by weight of a 30 solution, was 4 minutes. To the oxidized working solu
mixture of 2-ethyltetrahydronanthraquinone and 2-ethylanthraquinone of which the tetrahydroamhraquinone
constituted 61.5% of the total ethyltetrasydroanthra
tion was added 0.02% by weight of working solution of
sulfuric acid and hydrogen peroxide was then extracted
from the working solution with water without any diñi
quinone and ethylanthraquinone was subjected to re
peated cyclic operations each cycle involving hydrogena~
tion of the wo?king solution, oxidation of the working
culty due to emulsitication. ,
35
-In an operation under conditions the same as Example
3 above the amount of ammonia was increased to 0.05 %,
the time required for oxidation was reduced to 2.52 min
solution, and extraction with water of the hydrogen
peroxide from the oxidized working solution. The hy
drogenation reaction is carried out by passing hydrogen
through the working solution containing 0.5% catalyst
consisting of 5% palladium deposited on carbon carrier
'
Example 4
40
at a temperature of 25° C. until 1200 volumes of hy
drogen per 100 volumes of working solution were ab
utes.
`
Example 5
A working solution comprising a mixed solvent in the
proportion of 24.6 parts by weight acetophenone, 30.3
parts by weight capryl alcohol, and 29.8 parts by weight
sorbed. The catalyst was then separated from the hy
drogenated working solution and the working solution 45 xylene and cotnaining as a solute 15.3% by weight of a
then subjected to oxidation at a temperature of 30° C.
mixture of Z-ethyltetrahydroanthraquinone and 2-ethylby passing air up through the hydrogenated working
anthraquinone of which the tetrahydroanthraquinone con
solution until 1000 volumes of oxygen per 100 volumes
stituted 66% of the total ethyltetrahydroanthraquinone
of working solution were absorbed by the working solu
and ethylanthraquinone was subjected to repeated cyclic
tion. The oxidized working solution was then scrubbed
operations each cycle involving hydrogenation of the
with water to remove the hydrogen peroxide product and
working solution, oxidation of the working solution, and
the working solution then returned for further hydro
extraction with water of the hydrogen peroxide- from the
genation to start another cycle.
oxidized working solution. The hydrogenation reaction
In the above operation the time required for effecting
is carried out by passing hydrogen through the working
oxidation of working solution in each cycle requires 17
solution containing 0.5% catalyst consisting of 5% pal
minutes, 50 seconds to 20 minutes.
ladium deposited on carbon carrier at a temperature of
In a series of comparative cyclic operations in accord
ance with the practice of the present invention 0.04 part
25° C., untli 1100 volumes of hydrogen per 100 volumes
of working solution were absorbed. The catalyst was
by weight of_ the working solution of sodium hydroxide
then separated from the hydrogenated working solution
and the working solution then subjected to oxidation at
a temperature of 30° C. by passing air up through the
hydrogenated’working solution until 950 volumes of oxy
was added to the working solution and subjected to oxida
tion. The time required for effecting the oxidation, i.e.
absorbing 1000 volumes of oxygen per 100 volumes of
working solution, was 3 minutes, 17 seconds to 3 minutes,
50 seconds. To the oxidized working solution was added
gen per 100 volumes of working solution were absorbd
by the working solution. The oxidized working solution
0.06% by weight of working solution of sulfuric acid
was then scrubbed with water to remove the hydrogen
and hydrogen peroxide was then extracted from the work
ing solution with water without any diñìculty due to
peroxide product and the working solution then returned
for further hydrogenation to start another cycle.
emulsitication.
y
In the above operation the time required for eiîecting
Example 3
oxidation of working solution in each cycle requires 15
A working solution comprising a mixed solvent in the 70 minutes, l0 seconds.
In a series of comparative cyclic operations in accord
proportion of 26.5 parts by weight acetophenone, 32.7
ance with the practice of the present invention 0.02 part
parts by weight capryl alcohol, and 25.1 parts by weight
xylene and containing as a solute 15.7% by weight of a
mixture of 2>ethyltetrahydroanthraquinone and 2-ethyl
anthraquinone of which the tetrahydroanthraquinone con
rs
by weight of the working solution of sodium carbonate
was added to the working solution and subjected to oxida
tion. The time required for eiîecting the oxidation, i.e.
2,995,424
absorbing 950 volumes of oxygen per 100 volumes of `
the range of about 0.002% to about 0.25%, by weigh
working solution, was l1 minutes, 20 seconds. To the
oxidized working solution was added 0.04% by weight of
of sodium hydroxide.
-
'
~
S. Ina cyclic process for the production of hydrogen
peroxide involving hydrogenating a working solution
comprising a tetrahydroanthraquinone compound dis
working solution of sulfuric acid and hydrogen peroxide
was then extracted from the working solution with water
solved in a water-immiscible solvent to convert the tetra
lwithout any dilliculty due to emulsiiication.
hydroanthraquinone compound to the corresponding
tetrahydroanthrahydroquinone compound, oxidizing the
Example 6
In an operation under conditions the same as Example '
hydrogenated working solution with elemental oxygen to
5 above the amount of sodium carbonate was increased
to 0.05%, the time required `for oxidation was reduced to
5.0 minutes.
produce the tetrahydroanthraquinone compound and hy
drogen peroxide, and separating hydrogen peroxide'from
the oxidized working solution, and recycling the oxidized
working solution for further hydrogenation the improve
ment which comprises effecting oxidation of the working
Although certain preferred embodiments of the inven
tion have been disclosed for purpose of` illustration, it
will be evident that various changes and modiñcations may
be made therein without departing from the scope and
spirit of the invention.
solution in the presence of a small amount, within the
range of about 0.002% to about 0.25% by weight of~
ammonia.
I claim:
'
6. A cyclic process for the production of hydrogen
l. In a cyclic process for the production of hydrogen
peroxide
which comprises hydrogenating the working so
peroxide involving hydrogenating a working solution com-_ 20 lution comprising
an alkylated anthraquinone dissolved in
prising a tetrahydroanthraquinone compound dissolved in
a water-immiscible solvent to convert the anthraquinone
a water-ímmiscible solvent to convert the tetrahydro
anthraquinone compound to the corresponding tetrahydro
anthrahydroquinone compound, oxidizing the hydrogen
to the hydroquinone with concomitant formation as- a
oxide, and separating hydrogen peroxide from the oxidized
working solution, and recycling the oxidized working solu
tion for further hydrogenation the improvement which
comprises effecting oxidation of the working solution in
lution with elemental oxygen in the presence of a small
amount, within the range of about 0.002% to about
side reaction of tetrahydroanthraquinone resulting from
addition of hydrogen to the aromatic nucleus of the
ated working solution with elemental oxygen to produce 25 the
anthraquinone, oxidizing the hydrogenated working so
the tetrahydroanthraquinone compound and hydrogen per
the presence of a small amount, within the range of about
0.002% to about 0.25%, by weight of a water soluble
0.25 %, by weight of a water-soluble ionizable inorganic
alkaline compound to convert anthrahydroquinones to the
30
corresponding anthraquinone and produce hydrogen
peroxide, adding a small amount of acid to the oxidized
ionizable inorganic alkaline compound.
working solution and extracting hydrogen peroxide from
anthraquinone compound to the corresponding tetrahydro
anthrahydroquinone compound, oxidizing the hydrogen
peroxide which comprises hydrogenating the working so
lution comprising an alkylated tetrahydroanthraquinone
said oxidized working solution by passing the oxidized
2.. In a cyclic process for the production of hydrogen
solution
in intimate contact with water, and recycling
peroxide involving hydrogenating a working solution com 35
the resultant working solution for further hydrogenation.
prising a tetrahydroanthraquinone compound dissolved in
7. A cyclic process for the production of hydrogen
, a water-immiscible solvent to convert the tetrahydro
ated working solution with elemental oxygen to produce 40 dissolved in a water-immiscible solvent to convert the al
kylated tetrahydroanthraquinone to the alkylated tetrahy
the tetrahydroanthraquinone compound and hydrogen
peroxide, and separating hydrogen peroxide from the oxi
dized working solution, and recycling the oxidized work
ing solution for further hydrogenation the improvement
which comprises eiïectin'g oxidation of the working solu
droanthrahydroquinone, oxidizing the hydrogenated work
ing solution with elemental oxygen in the presence
l of a small amount, within the range of about 0.002%
to about 0.25 %, by weight of a water-soluble ionizable
tion in the presence of a small amount, within the range 45 inorganic alkaline compound to convert the alkylated
tetrahydroanthrahydroquinone to the corresponding al
kylated tetrahydroanthraquinone, adding a small amount
of acid to the oxidized working solution and extracting
3. In a cyclic process for the production of hydrogen
hydrogen peroxide from said oxidized working solution
peroxide involving hydrogenating a working solution
comprising a tetrahydroanthraquinone compound dis 50 by passing the oxidized solution in intimate contact with
water, and recycling the resultant working solution for
solved in a water-immiscible solvent to convert the tetra
further hydrogenation.
hydroanthraquinone compound to the corresponding
8. A cyclic process for the production of hydrogen
tetrahydroanthrahydroquinone compound, oxidizing the
peroxide which comprises hydrogenating the working so
hydrogenated working solution with elemental oxygen to
produce the tetrahydroanthraquinone compound and hy 55 lution comprising an alkylated tetrahydroanthraquinone
of about 0.005% to 0.02%, by weight vof a water-soluble
ionizable inorganic alkaline compound.
drogen peroxide, and separating hydrogen peroxide from
the oxidized working solution, and recycling the oxidized
working solution for further hydrogenation the improve
ment which comprises etîecting oxidation of the Working
dissolved in a water-immiscible solvent in the presence of
a palladium catalyst to convert the alkylated tetrahydro
anthraquinone to the alkylated tetrahydroanthrahydro
quinone, oxidizing the hydrogenated working solution
solution in the presence of a small amount, within the 60 with elemental oxygen in the presence of a small amount,
within the range of about 0.002% to about 0.25%, by
range of about'0.002% to about 0.25%, by weight an
weight of an alkali metal hydroxide to convert the al
alkali metal hydroxide.,
kylated tetrahydroanthrahydroquinone to the correspond
4. In a cyclic process for the production of hydrogen
ing alkylated tetrahydroanthraquinone, adding an amount
peroxide involving hydrogenating a working solution
comprising a tetrahydroanthraquinone compound dis 65 of acid at least equal to the weight of oxidation cata
lyst to the oxidized working solution and extracting hy
drogen peroxide from said oxidized working solution by
passing the oxidized solution in intimate contact with
water, and recycling the resultant working solution for
hydrogenated working solution with elemental oxygen to
produce the tetrahydroanthraquinone compound and hy 70 further hydrogenation.
9. A cyclic process for the production of hydrogen
drogen peroxide, and separating hydrogen peroxide from
peroxide which comprises hydrogenating the working so
the oxidized working solution, and recycling the oxidized
lution comprising an alkylated tetrahydroanthraquinone
working solution for further hydrogenation the improve
dissolved in a water-immiscible solvent to convert the al
ment which comprises effecting oxidation of the work
ing solution in the presence of a small amount, within 15 kylated tetrahydroanthraquinone to the alkylated tetra
solved in a water-immiscible solvent to convert the tetra
hydroanthraquinone compound to the corresponding
tetrahydroanthrahydroquinone compound, oxidizing the
2,995,424
12
"
v
,
hydroanthrahydroquînone, oxidizing the hydrogenated
of a small amount, within the range of about 0.005% to
working solution with> elemental oxygen in the presence of
0.02%, by weight of ammonia to convert the alkylated
tetrahydroanthrahydroquinone to the corresponding al
kylated tetrahydroanthraquinone, adding 0.002% to 0.5%
by weight of acid to the oxidized working solution by
a small amount, within the range of about 0.005% to
0.02%, by weight of sodium hydroxide to convert‘the
alkylated tetrahydroanthrahydroquinone to the corre
sponding alkylated tetrahydroanthraquinone, adding
passing the oxidized solution in intimate contact with wa
0.002% to 0.5% by weight of acid to the oxidized
ter, and recycling the resultant working solution for fur
working solution andlextracting hydrogen peroxide from
said oxidized working solution by passing the oxidized
ther hydrogenation.
solution in intimate contact with water, and recycling 10
the resultant working solution for further hydrogenation.
10. A cyclic process for the production of hydrogen
peroxide which comprises hydrogenating the working so
lution comprising an alkylated tetrahydroanthraquinone
dissolved in a Water-immiscible solvent to convert the al
-
References Cited in the tile of this patent
UNITED STATES PATENTS
2,158,525
2,901,491
'2,909,532
Riedl et al. _______ --..._.. May 16, 1939
Eller et al ............ _.- Aug. 25, 1959
Cosley et al. ......... _- Oct. 20, 1959
kylated tetrahydroanthraquinone to the alkylated tetra
OTHER REFERENCES
hydroanthrahydroquinone, oxidizing the hydrogenated
Walter C. Schumb: Hydrogen Peroxide, Reinhold Pub
liahing Co., New York, NLY., page 527 (1955).
working solution with elemental oxygen in the presence
AJ

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