Note: Descriptions are shown in the official language in which they were submitted.
CA 02202435 1997-04-11
- 1 -
SPECIFICATION
TITLE OF THE INVENTION
REGENERATION METHOD OF WORKING SOLUTION
BACKGROUND OF THE INVENTION
(i) Field of the Invention
The present invention relates to a regeneration
method of a working solution in a hydrogen peroxide produc-
tion process. More specifically, the present invention
relates to a regeneration method of a working solution by
which various by-products which do not participate in the
production of hydrogen peroxide and which are present in the
working solution in a hydrogen peroxide production process
utilizing an anthraquinone method can efficiently be con-
verted into anthraquinones effective as reaction media for
the production of hydrogen peroxide.
(ii) Description of the Related Art
A main production process of hydrogen peroxide which
has currently been practiced on an industrial scale is
called an anthraquinone method in which anthraquinones are
used as reaction media. In general, the anthraquinones are
used by dissolving them in an appropriate organic solvent.
This organic solvent may be a single organic solvent or a
mixed organic solvent, but it is usually a mixture of two
organic solvents. The solution obtained by dissolving the
anthraquinones in the organic solvent is called "a working
solution".
CA 02202435 1997-04-11
- 2 -
According to the anthraquinone method, the anthra-
quinones in the working solution are subjected to reduction
(hereinafter referred to as "the hydrogenation") with hydro-
gen in the presence of a catalyst in a reduction step to
produce corresponding anthrahydroquinones. Next, in an
oxidation step, the anthrahydroquinones are oxidized with
air or an oxygen-containing gas to convert the anthrahydro-
quinones into the anthraquinones again and to simultaneously
produce hydrogen peroxide. Hydrogen peroxide produced in
the working solution is usually extracted with water in an
extraction step to be separated from the working solution.
The working solution from which hydrogen peroxide has been
separated is returned to the reduction step again, thereby
forming a cyclic process. This cyclic process can produce
hydrogen peroxide substantially from hydrogen and air, and
hence it is an extremely efficient process. This cyclic
process has already been used for the industrial production
of hydrogen peroxide.
In the hydrogen peroxide production process utiliz-
ing the anthraquinone method, the anthraquinones contained
as the reaction media in the working solution are reduced
into the anthrahydroquinones, and they are further oxidized
to produce the anthraquinones and hydrogen peroxide. While
this procedure is repeated, alkyloxyanthrones, alkyltetra-
hydroanthraquinone epoxides and the like are produced by
side reactions. These alkyloxyanthrones, alkyltetrahydro-
anthraquinone epoxides and the like cannot produce hydrogen
peroxide, even when repeatedly subjected to the reduction
CA 02202435 1997-04-11
- 3 -
and oxidation. The production of these useless compounds is
very small per circulation of the reduction and oxidation,
but while the circulation is repeated, the above-mentioned
compounds are accumulated in the working solution and causes
various troubles.
If the nuclei of the alkylanthraquinones are hydro-
genated, the alkyltetrahydroanthraquinones are produced, but
these alkyltetrahydroanthraquinones have an ability of
producing hydrogen peroxide by the repetition of the reduc-
tion and oxidation like the alkylanthraquinones. However,
the alkyltetrahydroanthraquinones can easily be obtained by
reducing the alkylanthraquinones, but the alkyltetrahydro-
anthraquinones obtained by the reduction have a drawback
that their oxidation rate is low. Therefore, as indicated
by German Patent No. 2003268, in the case that the alkyl-
tetrahydroanthraquinones are used as the media for the
reduction and oxidation, an extremely large energy is re-
quired in the oxidation step, and hence half or more of the
total energy required in a circulation process is consumed
in the oxidation step, which leads to problems regarding an
apparatus and economy. As one means for solving these
problems, for example, in U.S. Patent No. 5,399,333, ratios
of the reduction and oxidation between the alkylanthraqui-
nones and the alkyltetrahydroanthraquinones can be con-
trolled in a suitable range to obtain an economically advan-
tageous process. However, when the alkyltetrahydroanthra-
quinones gradually increase and the ratios of the reduction
and oxidation increase, the above-mentioned problems regard-
CA 02202435 1997-04-11
4 -
ing the apparatus and economy similarly come up.
In view of the above-mentioned problems, in the
hydrogen peroxide production process utilizing the anthra-
quinone method, there are required a step in which the
alkyltetrahydroanthraquinones and the alkylanthraquinones
are regenerated from compounds such as the alkyltetrahydro-
anthraquinone epoxides and the alkyloxyanthrones and which
cannot produce hydrogen peroxide, and a step in which the
alkylanthraquinones are regenerated from the alkyltetra-
hydroanthraquinones. Thus, many suggestions have been made
so far.
In Japanese Patent Publication No. 8806/1964, it has
been suggested that inert components are converted into the
alkyltetrahydroanthraquinones by treating the working solu-
tion with an alkali and an aqueous alkali solution. Fur-
thermore, in Japanese Patent Publication No. 11658/1968, it
has been reported that the reduced working solution is
treated with caustic soda or sodium silicate at 120 C to
regenerate the alkyltetrahydroanthraquinone epoxides. How-
ever, when the working solution in which a part of the
anthraquinones are present as the anthrahydroquinones ob-
tained by their reduction is brought into contact with an
aqueous alkali solution, the anthrahydroquinones are ex-
tracted with the aqueous alkali solution, which leads to an
economical problem, i.e., the loss of the expensive an-
thraquinones.
Japanese Patent Publication No. 19164/1970 has
reported that the regeneration of the working solution can
CA 02202435 1997-04-11
- 5 -
be accomplished by treating the working solution with ozone,
further treating it with an aqueous caustic soda solution,
and then passing it through active alumina at 70 to 75 C.
However, this regeneration method comprises 3 steps and it
is complicated, and since expensive ozone is used, problems
regarding economy and an apparatus are present.
Japanese Patent Publication No. 41040/1974 has
suggested a method for regenerating the alkyloxyanthrones by
treating the working solution at 130 C in the presence of a
catalyst supporting palladium by the use of an olefin, but a
large amount of the'olefin and the expensive platinum group
metal are used in this method. For these reasons, this
method is also considered to be an economically disadvanta-
geous process.
Furthermore, as a method for converting the alkyl-
tetrahydroanthraquinones into the alkylanthraquinones,
Japanese Patent Publication No. 4474/1964 has reported that
the alkyltetrahydroanthraquinones can be converted into the
alkylanthraquinones by bringing alumina, magnesia, a spinel
of magnesia-alumina, carbon, or a metal having a hydrogena-
tion ability such as palladium, platinum or nickel into
contact with the working solution and a compound having an
unsaturated bond such as an olefin. Also in this case,
however, in order to heighten a reaction rate, a large
amount of the olefin is used and the employment of the
expensive platinum group metal is required. Hence, the
reported method is also considered to be an economically
disadvaritageous process.
CA 02202435 1997-04-11
- 6 -
As understood from the foregoing, the regeneration
methods of the working solution by the conventional tech-
niques have some problems regarding an apparatus and econ-
omy. For example, a plurality of steps are required and so
the operation is intricate, or the addition of a compound
other than the catalyst is necessary, or the anthraquinones
are probably lost in a certain ratio.
Furthermore, in the conventional techniques, it has
not been solved that the alkylanthraquinones and the
alkyltetrahydroanthraquinones are regenerated from the
alkyloxyanthrones and the alkyltetrahydroanthraquinone
epoxides and simultaneously the alkyltetrahydroanthra-
quinones are converted into the alkylanthraquinones.
On the other hand, the present inventors have found
that, in the case that the working solution containing at
least the alkyltetrahydroanthraquinones as the anthraqui-
nones is repeatedly reduced and oxidized to produce hydrogen
peroxide, alkyltetrahydrooxyanthrones are accumulated in the
working solution. The alkyltetrahydrooxyanthrones do not
produce hydrogen peroxide, even when repeatedly subjected to
the reduction and oxidation, and therefore, the alkyltetra-
hydrooxyanthrones accumulated in the working solution by
repeating the circulation inconveniently cause various
troubles. In addition, this fact leads to the loss of the
anthraquinones effective to produce hydrogen peroxide, which
is economically disadvantageous. The present inventors have
found that when the reduced working solution is treated with
a catalyst such as alumina with a view to particularly
CA 02202435 1997-04-11
- 7 -
regenerating the alkyltetrahydroanthraquinone epoxides, the
concentration of the alkyltetrahydrooxyanthrones increases.
For the purpose of solving this problem, in the hydrogen
peroxide production process utilizing the anthraquinone
method, it is necessary that the alkyltetrahydroanthra-
quinones should be regenerated from the alkyltetrahydrooxy-
anthrones.
As the conventional techniques regarding the regen-
eration method of the working solution, in addition to the
above-mentioned techniques, there have been reported a
production method of a desired compound from the alkyltetra-
hydroanthraquinone epoxides in Japanese Patent Publication
No. 30801/1982, and a method for regenerating the alkyl-
anthraquinones from the alkyltetrahydroanthraquinones in
"Studies in Surface Science and Catalysis", Vol. 88, p. 635
(1994).
In these conventional techniques, however, the
regeneration from the alkyltetrahydrooxyanthrones in the
working solution has not been described at all.
SUMMARY OF THE INVENTION
In view of such circumstances, the present invention
has now been developed, and the first object of the present
invention is to provide a regeneration method of a working
solution in a hydrogen peroxide production process utilizing
an anthraquinone method which comprises the step of convert-
ing alkyloxyanthrones and alkyltetrahydroanthraquinones in
the working solution into alkylanthraquinones, and convert-
CA 02202435 1997-04-11
- 8 -
ing alkyltetrahydroanthraquinone epoxides in the working
solution into alkyltetrahydroanthraquinones.
The second object of the present invention is to
provide a regeneration method of a working solution in a
hydrogen peroxide production process utilizing an anthraqui-
none method which comprises the step of converting alkyl-
tetrahydrooxyanthrones in the working solution into alkyl-
tetrahydroanthrahydroquinones.
The present inventors have intensively researched to
achieve the above-mentioned objects. As a result, it has
been found that the'first object of the present invention
can be achieved by bringing at least a part of an unreduced
working solution into contact with a catalyst mainly com-
prising a y-alumina at a specific temperature. Furthermore,
the second object of the present invention can be achieved
by bringing a working solution containing alkyltetrahydro-
anthrahydroquinones at a specific concentration into contact
with a catalyst mainly comprising a y-alumina at a specific
temperature.
The present invention has been completed on the
basis of the above-mentioned findings.
That is to say, the first object of the present
invention can be achieved by a regeneration method of a
working solution which comprises the step of repeatedly
reducing and oxidizing the working solution containing
alkylanthraquinones and alkyltetrahydroanthraquinones as
anthraquinones to produce hydrogen peroxide, wherein at
least a part of the unreduced working solution is brought
CA 02202435 2004-11-12
73162-106
- 9 -
into contact with a catalyst mainly comprising a y-alumina
at a temperature of 60 to 150 C (the first method).
The second object of the present invention can be
achieved by a regeneration method of a working solution
which comprises the step of repeatedly reducing and oxidiz-
ing the working solution containing at least alkyltetra-
hydroanthraquinones as anthraquinones to produce hydrogen
peroxide, wherein the working solution is brought into
contact with a catalyst mainly comprising a y-alumi.na at a
temperature of 60 to 150 C under conditions that a concen-
tration h(mol/liter) of the alkyltetrahydroanthrahydro-
quinones in the working solution before the catalytic
treatment meets the equation
(0.0018xt-0.0285)xhs0.05
wherein t is a treatment temperature ( C),
to convert alkyltetrahydrooxyanthrones in the working solu-
tion into the alkyltetrahydroanthrahydroquinones (the second
method).
DETAILED DESCRIPTION OF THE PRESENT INVENTION
A working solution which can be applied to a method
of the present invention is a solution containing anthra-
quinones as reaction media or anthrahydroquinones which are
their hydrides, and this solution can be used as a circulat-
ing solution in a hydrogen peroxide production process
utilizing an anthraquinone method.
In the hydrogen peroxide production process utiliz-
ing the anthraquinone method, the working solution contain-
CA 02202435 1997-04-11
- 10 -
ing the anthraquinones as the reaction media is first re-
duced in a reduction step with hydrogen to hydrogenate the
anthraquinones in the working solution, whereby correspond-
ing anthrahydroquinones are produced. Next, this reduced
solution is oxidized in an oxidation step with an oxygen-
containing gas to convert the anthrahydroquinones into the
corresponding anthraquinones again and to simultaneously
produce hydrogen peroxide. Hydrogen peroxide in the working
solution is extracted in an extraction step usually with
water to separate it from the working solution. The working
solution from which hydrogen peroxide has been separated is
returned to the reduction step again. As understood from
the foregoing, by the repetition of the reduction and oxida-
tion treatment of the anthraquinones, hydrogen peroxide can
continuously be produced from hydrogen and air.
No particular restriction is put on a solvent for
use in the preparation of the working solution which can be
used in this hydrogen peroxide production process, but
examples of the preferable solvent include a combination of
an aromatic hydrocarbon and a higher alcohol, a combination
of an aromatic hydrocarbon and a carboxylic acid ester of
cyclohexanol or an alkylcyclohexanol, and a tetra-
substituted urea. A combination of trimethylbenzene and
diisobutylcarbinol is particularly preferable.
Furthermore, as the anthraquinones which are the
reaction media, alkylanthraquinones and alkyltetrahydro-
anthraquinones can be used. Here, examples of the alkyl-
tetrahydroanthraquinones include amyltetrahydroanthraqui-
-- - - --------- - -
CA 02202435 1997-04-11
- 11 -
none, ethyltetrahydroanthraquinone, t-butyltetrahydro-
anthraquinone and mixtures thereof. In addition, examples
of the alkylanthraquinones include amylanthraquinone, ethyl-
anthraquinone, t-butylanthraquinone and mixtures thereof.
In the first place, the first method will be
described.
In the first method, the working solution con-
taining the alkylanthraquinones and the alkyltetrahydro-
anthraquinones can be used. In this case, the alkyl-
anthraquinones may be used singly or in a combination of two
or more thereof. Furthermore, the alkyltetrahydroanthra-
quinones may also be used singly or in a combination of two
or more thereof.
In the first method, the unreduced working solu-
tion is used. If the reduced working solution is used, the
rate of regenerating the alkylanthraquinones from the
alkyltetrahydroanthraquinones inconveniently lowers, and
what is worse, other by-products are liable to be produced
in large quantities.
Preferable examples of the unreduced working solu-
tion include a solution containing 0.05 mol/liter or more of
the alkyltetrahydroanthraquinones, a solution containing
0.15 mol/liter or less of alkyltetrahydroanthrahydroquinones
and a solution containing 0.05 mol/liter or more of the
alkyltetrahydroanthraquinones and 0.15 mol/liter or less of
the alkyltetrahydroanthrahydroquinones.
In the first method, at least a part of the
unreduced working solution is brought into contact with the
73162-106
CA 02202435 2006-12-22
73162-106
- 12 -
catalyst mainly comprising a y-alumina. This catalyst
mainly comprising the y-alumina has a high activity and is
economically advantageous. No particular restriction is put
on the particle size of the catalyst, but it is preferably
in the range of 8 to 100 mesh. If the particle size is less
than this range, a pressure loss in a reactor inconveniently
increases, and on the other hand, if it is larger than the
above-mentioned range, the catalytic activity inconveniently
deteriorates.
No particular restriction is put on the kind of
y-alumina, and the commercially available y-alumina can
usually widely be used. Furthermore, in the present inven-
tion, there can also be used a catalyst comprising this
y-alumina and about 10 wt% or less of calcium oxide, magne-
sium oxide, copper oxide, or a substance mainly consisting
of them, for example, CaO=A12O3 or Mg0=A1203.
In the first method, the unreduced working
solution is brought into contact with the catalyst mainly
comprising the y-alumina, but in this case, a catalytic
treatment temperature is selected in the range of 60 to
150 C. If this temperature is less than.60 C, a reaction
rate is so low as to be impractical, and on the other hand,
if it is more than 150 C, useless reactions other than an
intended regeneration reaction easily occur. in addition, a
catalytic treatment time depends upon the kind of catalyst
and the catalytic treatment temperature, and it cannot be
decided sweepingly, but it is usually in the range of about
10 to 120 minutes. Moreover, no particular restriction is
- --- --------------- -
CA 02202435 1997-04-11
- 13 -
put on the type of a reactor which can be used in this
catalytic treatment, and any of a stirrer-equipped type, a
fixed bed type and a fluidized bed type can be used.
As described above, when the unreduced working
solution is simply regenerated by the use of the simple
apparatus and the inexpensive catalyst, the alkyloxy-
anthrones and the alkyltetrahydroanthraquinone contained in
the working solution can efficiently converted into alkyl-
anthraquinones, and the alkyltetrahydroanthraquinone epox-
ides contained in the working solution can efficiently
converted into the alkyltetrahydroanthraquinones without
losing the effective anthraquinones.
Next, the second method will be described.
In the second method, the working solution con-
taining at least the alkyltetrahydroanthraquinones is used,
but the working solution containing a mixture of the alkyl-
tetrahydroanthraquinones and the alkylanthraquinones is
particularly preferable. In this case, the alkyltetrahydro-
anthraquinones may be used singly or in a combination of two
or more thereof. Moreover, the alkylanthraquinones may be
used singly or in a combination of two or more thereof.
In this second method, either of the unreduced
working solution and the reduced working solution can be
used. As the catalyst which is brought into contact with
this working solution, the catalyst mainly comprising a
y-alumina can be used, but this catalyst may be the same as
described in the first method.
In the second method, the working solution is
73162-106
CA 02202435 2006-12-22
73162-106
- 14 -
brought into contact with the catalyst mainly comprising the
y-alumina at a temperature of 60 to 150 C under conditions
that a concentration h (mol/liter) of the alkyltetrahydro-
anthrahydroquinones in the working solution before the
catalytic treatment meets the equation
(0.0018xt-0.0285)xh50.05
wherein t is a treatment temperature ( C),
to convert alkyltetrahydrooxyanthrones in the working solu-
tion into the alkyltetrahydroanthrahydroquinones. In this
case, as the concentration of the alkyltetrahydroanthra-
hydroquinones in the working solution is low, the concentra-
tion of the alkyltetrahydrooxyanthrones in the regenerated
working solution can be lowered. Furthermore, as the tem-
perature is low, the concentration of the alkyltetrahydro-
oxyanthrones in the regenerated working solution can be
lowered. However, if the temperature is less than 60 C, a
reaction rate is so low as to be impractical. The prefer-
able treatment conditions are that the treatment temperature
is in the range of 60 to 150 C and the concentration h
(mol/liter) of the alkyltetrahydroanthrahydroquinones in the
working solution before the catalytic treatment is 0.15
mol/liter or less and meets the equation
(0.0018xt-0.0285)xh50.02
wherein t is a treatment temperature ( C).
The concentration of the alkyltetrahydroanthrahydro-
quinones in the working solution can be adjusted suitably by
oxidizing the working solution. Moreover, no particular
restriction is put on the type of a reactor which can be
CA 02202435 1997-04-11
- 15 -
used in this catalytic treatment, and any of a stirrer-
equipped type, a fixed bed type and a fluidized bed type can
be used.
When the working solution is regenerated under such
conditions, the alkyltetrahydrooxyanthrones in the working
solution can efficiently be converted into the alkyltetra-
hydroanthrahydroquinones.
Next, the present invention will be described in
more detail, but the scope of the present invention should
not be limited to these examples.
Example 1
Amyltetrahydroanthraquinone was dissolved in a mixed
solvent of 60 vol% of 1,2,4-trimethylbenzene and 40 vol% of
diisobutylcarbinol to prepare a working solution in which
the concentration of amyltetrahydroanthraquinone was 0.225
mol/liter, and the working solution was then sufficiently
oxidized to regulate, to 0.000 mol/liter, the concentration
of anthrahydroquinones which were reductants. In this
example, AA400G (14 to 48 mesh) made by Alcan Chemicals Co.,
Ltd. was used as a y-alumina. Next, 100 ml of the above-
mentioned working solution was placed in a 200-m1 flask, and
the introduction of nitrogen was begun and the working
solution was then heated up to 120 C with stirring. When
the working solution had reached 120 C, 10.0 g of the
y-alumina was fed, and reaction was carried out for 1 hour.
A reaction temperature was controlled to 120 C.
The working solution discharged from a reactor was
analyzed in the following manner, and as a result, it was
CA 02202435 1997-04-11
- 16 -
apparent that the concentration of amyltetrahydroanthra-
quinone was 0.194 mol/liter and that of amylanthraquinone
was 0.021 mol/liter. The amount of regenerated alkyltetra-
hydroanthraquinones was 0.021 mol/liter.
[Analysis of the working solution after the comple-
tion of the reaction]
The working solution discharged from the reactor was
cooled by a cooling tube, sufficiently oxidized, washed with
water, dehydrated, filtered, and then analyzed by liquid
chromatography to measure the concentrations of various
components.
The concentration of the anthrahydroquinones in the
working solution was calculated on the basis of the amount
of absorbed oxygen per unit volume of the working solution.
Furthermore, the amount of alkylanthraquinones into which
the alkyltetrahydroanthraquinones were converted was calcu-
lated by deducting the amount of the alkylanthraquinones
regenerated from alkyloxyanthrones, from the increased
amount of the alkylanthraquinones in the working solution
after the reaction. The value obtained by this calculation
will simply be called the regeneration of the alkyltetra-
hydroanthraquinones.
Example 2
Reaction was carried out by the same procedure as in
Example 1 except that there was used a working solution in
which amyltetrahydroanthraquinone was partially reduced so
that the concentration of amyltetrahydroanthrahydroquinone
might be 0.080 mol/liter and that of alkyltetrahydroanthra-
CA 02202435 1997-04-11
- 17 -
quinones might be 0.145 mol/liter.
The working solution discharged from the reactor was
analyzed in the same manner as in Example 1, and as a re-
sult, the concentration of amyltetrahydroanthraquinone was
0.196 mol/liter and that of amylanthraquinone was 0.010
mol/liter. The regeneration of the alkyltetrahydroanthra-
quinones was 0.010 mol/liter.
Example 3
There was used a working solution obtained in an
experimental device in which the working solution containing
amylanthraquinone and amyltetrahydroanthraquinone as reac-
tion media was alternately reduced and oxidized to produce
hydrogen peroxide. In this working solution, the concentra-
tion of amyltetrahydroanthraquinone was 0.150 mol/liter,
that of amyltetrahydroanthrahydroquinone was 0.05 mol/liter,
that of amylanthraquinone was 0.580 mol/liter, that of
amyloxyanthrone was 0.012 mol/liter, and that of amyltetra-
hydroanthraquinone epoxide was 0.010 mol/liter. In this
working solution, solid components other than mentioned
above were contained in an amount of about 10 wt% of the
total solid components, but since they scarcely changed in
this example, they will not particularly be referred to
hereinafter. A reactor was filled with 300 ml of AA400G (14
to 48 mesh) made by Alcan Chemicals Co., Ltd. as a
y-alumina. After the reactor had sufficiently been purged
with nitrogen, the working solution prepared above was fed
at 220 ml/hr to carry out regeneration reaction. A reaction
temperature was controlled to 120 C.
CA 02202435 1997-04-11
- 18 -
The regeneration reaction of the working solution
was accomplished by feeding the working solution from bottom
to top of the fixed bed type reactor filled with the
y-alumina. The fixed bed type reactor was made of stainless
steel, and this reactor was fixed at upper and lower posi-
tions of its catalyst filling portion by a filter having a
mesh size of about 20 m. The reactor itself was also
heated from the outside, but the working solution was previ-
ously heated up to a predetermined temperature and then
introduced into the catalyst filling portion so that the
temperature of the catalyst filling portion might be uniform
as much as possible. Furthermore, the working solution to
be fed was sufficiently nitrogen-sealed prior to its intro-
duction into the reactor.
The working solution (after 24 hours had lapsed from
the start of the reaction) discharged from the reactor was
analyzed in the same manner as in Example 1. As a result,
the concentration of amyltetrahydroanthraquinone was 0.188
mol/liter, that of amylanthraquinone was 0.607 mol/liter,
and that of amyltetrahydroanthraquinone epoxide and amyl-
oxyanthrone was 0.000 mol/liter. The regeneration of the
alkyltetrahydroanthraquinones was 0.015 mol/liter.
Example 4
Reaction was carried out by the same procedure as in
Example 3 except that there was used a working solution in
which the concentration of amyltetrahydroanthraquinone was
0.08 mol/liter, that of amyltetrahydroanthrahydroquinone was
0.12 mol/liter, that of amylanthraquinone was 0.580 mol/li-
CA 02202435 1997-04-11
- 19 -
ter, that of amyloxyanthrone was 0.012 mol/liter, and that
of amyltetrahydroanthraquinone epoxide was 0.010 mol/liter.
The working solution (after 24 hours had lapsed from
the start of the reaction) discharged from a reactor was
sufficiently oxidized and then analyzed in the same manner
as in Example 1. As a result, the concentration of amyl-
tetrahydroanthraquinone was 0.190 mol/liter, that of amyl-
anthraquinone was 0.597 mol/liter, and that of amyltetra-
hydroanthraquinone epoxide and amyloxyanthrone was 0.000
mol/liter. The regeneration of the alkyltetrahydroanthra-
quinones was 0.005 mol/liter.
Example 5
Reaction was carried out by the same procedure as in
Example 3 except that a y-alumina, Sunbead AN made by Shoku-
bai Chemical Co., Ltd. was used as a catalyst.
A working solution (after 24 hours had lapsed from
the start of the reaction) discharged from a reactor was
sufficiently oxidized and then analyzed in the same manner
as in Example 1. As a result, the concentration of amyl-
tetrahydroanthraquinone was 0.188 mol/liter, that of amyl-
anthraquinone was 0.607 mol/liter, and that of amyltetra-
hydroanthraquinone epoxide and amyloxyanthrone was 0.000
mol/liter. The regeneration of the alkyltetrahydroanthra-
quinones was 0.015 mol/liter.
Example 6
Reaction was carried out by the same procedure as in
Example 3 except that a y-alumina, KHD-24 made by Sumitomo
Chemical Co., Ltd. was used as a catalyst.
CA 02202435 1997-04-11
- 20 -
A working solution (after 24 hours had lapsed from
the start of the reaction) discharged from a reactor was
sufficiently oxidized and then analyzed in the same manner
as in Example 1. As a result, the concentration of amyl-
tetrahydroanthraquinone was 0.190 mol/liter, that of amyl-
anthraquinone was 0.605 mol/liter, and that of amyltetra-
hydroanthraquinone epoxide and amyloxyanthrone was 0.000
mol/liter. The regeneration of the alkyltetrahydroanthra-
quinones was 0.013 mol/liter.
Example 7
Reaction was carried out by the same procedure as in
Example 1 except that a y-alumina, GB-13 made by Mizusawa
Chemical Co., Ltd. was used as a catalyst.
A working solution (after 24 hours had lapsed from
the start of the reaction) discharged from a reactor was
sufficiently oxidized and then analyzed in the same manner
as in Example 1. As a result, the concentration of amyl-
tetrahydroanthraquinone was 0.190 mol/liter, that of amyl-
anthraquinone was 0.605 mol/liter, and that of amyltetra-
hydroanthraquinone epoxide and amyloxyanthrone was 0.000
mol/liter. The regeneration of the alkyltetrahydroanthra-
quinones was 0.013 mol/liter.
Comparative Example 1
Reaction was carried out by the same procedure as in
Example 3 except that there was used a reduced working
solution in which the concentration of amyltetrahydroanthra-
quinone was 0.35 mol/liter, that of amyltetrahydroanthra-
hydroquinone was 0.165 mol/liter, that of amylanthraquinone
CA 02202435 1997-04-11
- 21 -
was 0.580 mol/liter, that of amyloxyanthrone was 0.012
mol/liter, and that of amyltetrahydroanthraquinone epoxide
was 0.010 mol/liter.
The working solution (after 24 hours had lapsed from
the start of the reaction) discharged from a reactor was
sufficiently oxidized and then analyzed in the same manner
as in Example 1. As a result, the concentration of amyl-
tetrahydroanthraquinone was 0.185 mol/liter, that of amyl-
anthraquinone was 0.593 mol/liter, and that of amyltetra-
hydroanthraquinone epoxide and amyloxyanthrone was 0.000
mol/liter. The regeneration of the alkyltetrahydroanthra-
quinones was 0.001 mol/liter.
Comparative Example 2
Reaction was carried out by the same procedure as in
Example 3 except that there was used a reduced working solu-
tion in which the concentration of amyltetrahydroanthra-
quinone was 0.000 mol/liter, that of amyltetrahydroanthra-
hydroquinone was 0.20 mol/liter, that of amylanthraquinone
was 0.44 mol/liter, that of amylanthrahydroquinone was 0.14
mol/liter, that of amyloxyanthrone was 0.012 mol/liter, and
that of amyltetrahydroanthraquinone epoxide was 0.010
mol/liter.
The working solution (after 24 hours had lapsed from
the start of the reaction) discharged from a reactor was
sufficiently oxidized and then analyzed in the same manner
as in Example 1. As a result, the concentration of amyl-
tetrahydroanthraquinone was 0.176 mol/liter, that of amyl-
anthraquinone was 0.557 mol/liter, that of amyltetrahydro-
CA 02202435 1997-04-11
-22-
anthraquinone epoxide was 0.000, and that of amyloxyanthrone
was 0.035 mol/liter. The regeneration of the alkyltetra-
hydroanthraquinones was 0.000 mol/liter.
Example 8
Reaction was carried out by the same procedure as in
Example 3 except that the reaction temperature of a working
solution was 100 C.
A working solution (after 24 hours had lapsed from
the start of the reaction) discharged from a reactor was
sufficiently oxidized and then analyzed in the same manner
as in Example 1. As a result, the concentration of amyl-
tetrahydroanthraquinone was 0.205 mol/liter, that of amyl-
anthraquinone was 0.597 mol/liter, and that of amyltetra-
hydroanthraquinone epoxide and amyloxyanthrone was 0.000
mol/liter. The regeneration of the alkyltetrahydroanthra-
quinones was 0.005 mol/liter.
Example 9
Reaction was carried out by the same procedure as in
Example 3 except that the reaction temperature of a working
solution was 80 C.
A working solution (after 24 hours had lapsed from
the start of the reaction) discharged from a reactor was
sufficiently oxidized and then analyzed in the same manner
as in Example 1. As a result, the concentration of amyl-
tetrahydroanthraquinone was 0.206 mol/liter, that of amyl-
anthraquinone was 0.594 mol/liter, that of amyltetrahydro-
anthraquinone epoxide was 0.005 mol/liter, and that of
amyloxyanthrone was 0.000 mol/liter. The regeneration of
CA 02202435 1997-04-11
- 23 -
the alkyltetrahydroanthraquinones was 0.002 mol/liter.
Comparative Example 3
Reaction was carried out by the same procedure as in
Example 3 except that the reaction temperature of a working
solution was 30 C.
A working solution (after 24 hours had lapsed from
the start of the reaction) discharged from a reactor was
sufficiently oxidized and then analyzed in the same manner
as in Example 1. As a result, the concentration of amyl-
tetrahydroanthraquinone was 0.200 mol/liter, that of amyl-
anthraquinone was 0.587 mol/liter, that of amyltetrahydro-
anthraquinone epoxide was 0.010 mol/liter, and that of
amyloxyanthrone was 0.005 mol/liter. The regeneration of
the alkyltetrahydroanthraquinones was 0.000 mol/liter.
Example 10
Reaction was carried out by the same procedure as in
Example 3 except that the reaction temperature of a working
solution was 60 C.
A working solution (after 24 hours had lapsed from
the start of the reaction) discharged from a reactor was
sufficiently oxidized and then analyzed in the same manner
as in Example 1. As a result, the concentration of amyl-
tetrahydroanthraquinone was 0.195 mol/liter, that of amyl-
anthraquinone was 0.594 mol/liter, that of amyltetrahydro-
anthraquinone epoxide was 0.009 mol/liter, and that of
amyloxyanthrone was 0.000 mol/liter. The regeneration of
the alkyltetrahydroanthraquinones was 0.002 mol/liter.
Example 11
CA 02202435 1997-04-11
- 24 -
Reaction was carried out by the same procedure as in
Example 3 except that there was used a working solution in
which the concentration of amyltetrahydroanthraquinone was
0.15 mol/liter, that of amyltetrahydroanthrahydroquinone was
0.05 mol/liter, that of amylanthraquinone was 0.532 mol/li-
ter, that of amyloxyanthrone was 0.06 mol/liter, and that of
amyltetrahydroanthraquinone epoxide was 0.010 mol/liter.
The working solution (after 24 hours had lapsed from
the start of the reaction) discharged from a reactor was
sufficiently oxidized and then analyzed in the same manner
as in Example 1. As a result, the concentration of amyl-
tetrahydroanthraquinone was 0.191 mol/liter, that of amyl-
anthraquinone was 0.594 mol/liter, that of amyltetrahydro-
anthraquinone epoxide was 0.006 mol/liter, and that of
amyloxyanthrone was 0.000 mol/liter. The regeneration of
the alkyltetrahydroanthraquinones was 0.002 mol/liter.
Example 12
A working solution was prepared in which the concen-
tration of amyltetrahydroanthrahydroquinone was 0.337
mol/liter, that of amyltetrahydroanthraquinone was 0.000
mol/liter, and that of amyltetrahydrooxyanthrone was 0.063
mol/liter. In this example, AA400G (14 to 48 mesh) made by
Alcan Chemicals Co., Ltd. was used as a y-alumina. Next,
100 ml of the above-mentioned working solution was placed in
a 200-m1 flask, and the introduction of nitrogen was begun
and the working solution was then heated up to 60 C with
stirring. When this working solution had reached 60 C, 10.0
g of the y-alumina was fed, and reaction was carried out for
CA 02202435 1997-04-11
- 25 -
2 hours. Afterward, the working solution was sufficiently
oxidized, washed with water, dehydrated, filtered, and then
analyzed by liquid chromatography to measure the concentra-
tions of various components. In consequence, the concentra-
tion of amyltetrahydroanthraquinone was 0.371 mol/liter, and
that of amyltetrahydrooxyanthrone was 0.029 mol/liter.
In this connection, for the preparation of the
working solution, a mixed solvent of 60 vol% of 1,2,4-
trimethylbenzene and 40 vol% of diisobutylcarbinol was used.
Furthermore, the analysis of the oxidized solution by the
liquid chromatography was carried out after all of alkyl-
tetrahydroanthraquinones in the working solution at the
start of the reaction had been reduced into alkyltetrahydro-
anthrahydroquinones. The concentration of anthrahydroqui-
nones in the working solution was calculated on the basis of
the amount of absorbed oxygen per unit volume of the working
solution (the same shall apply hereinafter).
Example 13
Reaction was carried out by the same procedure as in
Example 12 except that there was used a working solution in
which the concentration of amyltetrahydroanthrahydroquinone
was 0.000 mol/liter, that of amyltetrahydroanthraquinone was
0.337 mol/liter, and that of amyltetrahydrooxyanthrone was
0.063 mol/liter. After the completion of the reaction, the
concentrations of various components were measured. As a
result, the concentration of amyltetrahydroanthraquinone was
0.390 mol/liter, that of amyltetrahydrooxyanthrone was 0.005
mol/liter, and that of amylanthraquinone was 0.003 mol/li-
CA 02202435 1997-04-11
- 26 -
ter.
Example 14
Reaction was carried out by the same procedure as in
Example 12 except that there was used a working solution in
which the concentration of amyltetrahydroanthrahydroquinone
was 0.169 mol/liter, that of amyltetrahydroanthraquinone was
0.168 mol/liter, and that of amyltetrahydrooxyanthrone was
0.063 mol/liter. After the completion of the reaction, the
concentrations of various components were measured. As a
result, the concentration of amyltetrahydroanthraquinone was
0.382 mol/liter, and that of amyltetrahydrooxyanthrone was
0.017 mol/liter.
Example 15
Reaction was carried out by the same procedure as in
Example 12 except that there was used a working solution in
which the concentration of amyltetrahydroanthrahydroquinone
was 0.000 mol/liter, that of amyltetrahydroanthraquinone was
0.337 mol/liter and that of amyltetrahydrooxyanthrone was
0.063 mol/liter, and a reaction temperature was 80 C. After
the completion of the reaction, the concentrations of vari-
ous components were measured. As a result, the concentra-
tion of amyltetrahydroanthraquinone was 0.386 mol/liter,
that of amyltetrahydrooxyanthrone was 0.007 mol/liter, and
that of amylanthraquinone was 0.002 mol/liter.
Example 16
Reaction was carried out by the same procedure as in
Example 12 except that there was used a working solution in
which the concentration of amyltetrahydroanthrahydroquinone
CA 02202435 1997-04-11
- 27 -
was 0.051 mol/liter, that of amyltetrahydroanthraquinone was
0.286 mol/liter and that of amyltetrahydrooxyanthrone was
0.063 mol/liter, and a reaction temperature was 80 C. After
the completion of the reaction, the concentrations of vari-
ous components were measured. As a result, the concentra-
tion of amyltetrahydroanthraquinone was 0.383 mol/liter,
that of amyltetrahydrooxyanthrone was 0.013 mol/liter, and
that of amylanthraquinone was 0.002 mol/liter.
Example 17
Reaction was carried out by the same procedure as in
Example 12 except that there was used a working solution in
which the concentration of amyltetrahydroanthrahydroquinone
was 0.337 mol/liter, that of amyltetrahydroanthraquinone was
0.000 mol/liter and that of amyltetrahydrooxyanthrone was
0.063 mol/liter, and a reaction temperature was 80 C. After
the completion of the reaction, the concentrations of vari-
ous components were measured. As a result, the concentra-
tion of amyltetrahydroanthraquinone was 0.362 mol/liter,
that of amyltetrahydrooxyanthrone was 0.041 mol/liter, and
that of amylanthraquinone was 0.000 mol/liter.
Example 18
Reaction was carried out by the same procedure as in
Example 12 except that there was used a working solution in
which the concentration of amyltetrahydroanthrahydroquinone
was 0.000 mol/liter, that of amyltetrahydroanthraquinone was
0.337 mol/liter and that of amyltetrahydrooxyanthrone was
0.063 mol/liter, and a reaction temperature was 100 C.
After the completion of the reaction, the concentrations of
CA 02202435 1997-04-11
- 28 -
various components were measured. As a result, the concen-
tration of amyltetrahydroanthraquinone was 0.373 mol/liter,
that of amyltetrahydrooxyanthrone was 0.011 mol/liter, and
that of amylanthraquinone was 0.014 mol/liter.
Example 19
Reaction was carried out by the same procedure as in
Example 12 except that there was used a working solution in
which the concentration of amyltetrahydroanthrahydroquinone
was 0.182 mol/liter, that of amyltetrahydroanthraquinone was
0.155 mol/liter and that of amyltetrahydrooxyanthrone was
0.063 mol/liter, and a reaction temperature was 100 C.
After the completion of the reaction, the concentrations of
various components were measured. As a result, the concen-
tration of amyltetrahydroanthraquinone was 0.363 mol/liter,
that of amyltetrahydrooxyanthrone was 0.033 mol/liter, and
that of amylanthraquinone was 0.004 mol/liter.
Example 20
Reaction was carried out by the same procedure as in
Example 12 except that there was used a working solution in
which the concentration of amyltetrahydroanthrahydroquinone
was 0.000 mol/liter, that of amyltetrahydroanthraquinone was
0.337 mol/liter and that of amyltetrahydrooxyanthrone was
0.063 mol/liter, and a reaction temperature was 120 C.
After the completion of the reaction, the concentrations of
various components were measured. As a result, the concen-
tration of amyltetrahydroanthraquinone was 0.339 mol/liter,
that of amyltetrahydrooxyanthrone was 0.023 mol/liter, and
that of amylanthraquinone was 0.039 mol/liter.
CA 02202435 1997-04-11
-29-
Example 21
Reaction was carried out by the same procedure as in
Example 12 except that there was used a working solution in
which the concentration of amyltetrahydroanthrahydroquinone
was 0.167 mol/liter, that of amyltetrahydroanthraquinone was
0.170 mol/liter and that of amyltetrahydrooxyanthrone was
0.063 mol/liter, and a reaction temperature was 120 C.
After the completion of the reaction, the concentrations of
various components were measured. As a result, the concen-
tration of amyltetrahydroanthraquinone was 0.339 mol/liter,
that of amyltetrahydrooxyanthrone was 0.043 mol/liter, and
that of amylanthraquinone was 0.020 mol/liter.
Comparative Example 4
Reaction was carried out by the same procedure as in
Example 12 except that there was used a working solution in
which the concentration of amyltetrahydroanthrahydroquinone
was 0.337 mol/liter, that of amyltetrahydroanthraquinone was
0.000 mol/liter and that of amyltetrahydrooxyanthrone was
0.063 mol/liter, and a reaction temperature was 120 C.
After the completion of the reaction, the concentrations of
various components were measured. As a result, the concen-
tration of amyltetrahydroanthraquinone was 0.327 mol/liter,
and that of amyltetrahydrooxyanthrone was 0.063 mol/liter.
Comparative Example 5
Reaction was carried out by the same procedure as in
Comparative Example 4 except that a reaction temperature was
140 C. After the completion of the reaction, the concentra-
tions of various components were measured. As a result, the
CA 02202435 1997-04-11
- 30 -
concentration of amyltetrahydroanthraquinone was 0.327
mol/liter, and that of amyltetrahydrooxyanthrone was 0.074
mol/liter.
Comparative Example 6
Reaction was carried out by the same procedure as in
Example 12 except that there was used a working solution in
which the concentration of amyltetrahydroanthrahydroquinone
was 0.237 mol/liter, that of amyltetrahydroanthraquinone was
0.100 mol/liter and that of amyltetrahydrooxyanthrone was
0.063 mol/liter, and a reaction temperature was 150 C.
After the completion of the reaction, the concentrations of
various components were measured. As a result, the concen-
tration of amyltetrahydroanthraquinone was 0.320 mol/liter,
that of amyltetrahydrooxyanthrone was 0.064 mol/liter, and
that of amylanthraquinone was 0.014 mol/liter.
Comparative Example 7
Reaction was carried out by the same procedure as in
Comparative Example 4 except that a reaction temperature was
100 C. After the completion of the reaction, the concentra-
tions of various components were measured. As a result, the
concentration of amyltetrahydroanthraquinone was 0.347
mol/liter, and that of amyltetrahydrooxyanthrone was 0.053
mol/liter.
