WO 2005/063673 PCT/KR2004/003433
METHOD OF PRODUCING UNSATURATRD ALDEHYDE AND/OR
UNSATURATED FATTY ACID
Technical Field
5 The present invention relates to a method for
producing unsaturated aldehydes and/or unsaturated acids
from at least one compound selected from the group
consisting of propylene, propane, (meth) acrolein,
isobutylene, t-butyl alcohol, methyl-t-butyl ether and o-
10 xylene, by means of fixed-bed catalytic partial oxidation in
a shell-and-tube heat exchange type reactor, as well as to a
fixed-bed shell-and-tube heat exchange type reactor used in
the above method.
15 Background Art
A process for producing unsaturated aldehydes and/or
unsaturated acids from olefins is a typical example of
catalytic vapor phase oxidation.
To perform the partial oxidation of olefins, a
20 multimetal oxide containing molybdenum and bismuth or
vanadium or a mixture thereof is used as a catalyst.
Typically, the partial oxidation of olefins may be
exemplified by a process for producing (meth) acrolein or
(meth) acrylic acid by oxidizing propylene or isobutylene, a
25 process for producing phthalic anhydride by oxidizing
naphthalene or ortho-xylene or a process for producing
maleic anhydride by partially oxidizing benzene, butylene or
butadiene.
Generally, propylene or isobutylene is subjected to
30 two-step catalytic vapor phase partial oxidation to form
(meth) acrylic acid as a final product. More particularly, in
the first step, propylene or isobutylene is oxidized. By

WO 2005/063673 PCT/KR2004/003433
oxygen, diluted inert gas, water vapor and an optional
amount of catalyst to form (meth) acrolein as a main product.
In the second step, (meth) acrolein obtained from the
preceding step is oxidized by oxygen, diluted inert gas,
5 water vapor and an optional amount of catalyst to form
(meth) acrylic acid. The catalyst used in the first step is
an oxidation catalyst based on Mo-Bi, which oxidizes
propylene or isobutylene to form (meth) acrolein as a main
product. Additionally, a part of (meth) acrolein is further
10 oxidized on the same catalyst to form acrylic acid
partially. The catalyst used in the second step is an
oxidation catalyst based on Mo-V, which oxidizes
(meth) acrolein-containing mixed gas produced in the first
step, particularly (meth) acrolein, to form (meth) acrylic
15 acid as a main product.
Reactors for carrying out the above process are
realized in such a manner that each of the above two steps
are implemented in one system or in two different systems
(see OS Patent No. 4,256,783).
20 In general, catalytic vapor phase oxidation is
implimented as follows. At least one catalyst in the form of
granules is packed into reaction tubes, feed gas is supplied
to a reactor through the reaction tubes and the feed gas is
in contact with the catalyst in the reaction tubes to
25 perform vapor phase oxidation. Reaction heat generated
during the reaction is removed by heat transfer with a heat
transfer medium, wherein the temperature of the heat
transfer medium is maintained at a predetermined
temperature. Particularly, the neat transfer medium for heat
30 exchange is provided on the outer surface of the catalytic
tubes to perform heat transfer. A reaction product mixture
containing a desired product is collected via a duct and
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WO 2005/063673 PCT/KR2004/003433
then sent to a purification step. Generally, catalytic vapor
phase oxidation is a highly exothermic reaction. Therefore,
it is very important to control the reaction temperature in
a specific range and to downsize hot spots in the reaction
5 zone.
For example, vapor phase partial oxidation of
propylene or isobutylene using a metal oxide catalyst based
on molybdenum-bismuth-iron is an exothermic reaction.
Therefore, it has a problem in that a hot spot (a point
10 whose temperature is abnormally high) is generated in the
reactor. Such hot spots show a relatively high temperature
compared to other parts of the reactor. Accordingly, in hot
spots, complete oxidation proceeds rather than partial
oxidation, thereby increasing by-products such as COx and
15 decreasing the yield of (meth) acrylic acid and
(meth) acrolein. Additionally, excessive heat generated in a
hot spot causes migration of molybdsnum that is a main
element of the catalyst, resulting in deposition of
molybdenum in a catalytic layer having a relatively low
20 temperature and pressure drop in the catalytic layer,
degradation of catalytic activity and in shortening of the
lifetime of the catalyst. Therefore, yield of (meth) acrolein
and (meth) acrylic acid decreases.
Generally, various methods are known in order to
25 control the excessive heat at a hot spot in a catalytic
reaction accompanied with heat generation. Such methods
include a method for reducing the amount of feed gas to
decrease the space velocity and a method of using a reaction
tube having a relatively small inner diameter. However, when
30 the space velocity decreases, it is not possible to obtain
high productivity in an industrial scale. When the inner
diameter of a reaction tube decreases, it is difficult to
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WO 2005/063673 PCT/KR2004/003433
manufacture the reactor. Moreover, in the latter case, there
are disadvantages of economically unfavorable high cost
needed for manufacturing the reactor, and increased time and
labor needed for packing a catalyst. For these reasons,
5 there has been a continuous need for and research into a
method for producing unsaturated aldehydes and/or
unsaturated fatty acids with high yield and high
productivity by using a catalyst stably for a long time,
while avoiding the above problems according to the known
10 methods.
According to the prior art, disclosed is a reactor for
producing unsaturated aldehydes and/or unsaturated fatty
acids with high yield over a long time while extending the
lifetime of a catalyst, by controlling the excessive
15 reaction heat at the hot spot and optimizing catalytic
activity and selectivity. Japanese Laid-Open Patent Nos.
Sho53-3068861 and Hei-l0802A1 disclose a fixed-bed reactor
including a reaction zone for the first step of producing
acrolein as a main product, the reaction zone comprising a
20 catalytic bed that is formed of a catalyst mixed and diluted
with an inactive material and is packed in such a manner
that the ratio of the inactive material gradually decreases
from the inlet of the reactor toward the outlet of the
reactor, i.e., in the direction of reaction gas flow.
25 US Patent No. 5,198,531 discloses a fixed-bed multi-
tube type reactor for producing unsaturated aldehydes and
unsaturated fatty acids by means of catalytic vapor phase
oxidation of at least one compound selected from the group
consisting of propylene, isobutylene, t-butyl alcohol and
30 methyl-t-butyl ether with molecular oxygen or molecular
oxygen-containing gas. The above reactor includes a
plurality of reaction zones each packed with a different
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WO 2005/063673 PCT/KR2004/003433
composite oxide-based catalyst having a different occupation
vaslume along the axial direction of such reaction tube,
wherein the volume is controlled so that it decreases from
the gas inlet to the outlet. Korean Laid-Open Patent No.
5 2001-80871 discloses a method for producing acrolein (ACR)
and acrylic acid (AA) by means of vapor phase oxidation of
propylene with molsculat oxygen or molecular oxygen-
containing gas in a fixed-bed cylindrical reactor. According
to the above method, a plurality of catalysts having
10 different activities are obtained by controlling (a) the
valume occupied by a catalyst, (b) sintering temperature,
and/or (c) kind and/or amount of alkali metal elements.
Additionally, the catalytic bed in each reaction tube is
divided into two or more reaction zones along the axial
15 direction, the reaction zones being packed with the
catalysts in such a manner that the catalytic activity
increases from the reaction gas inlet to the outlet.
As described in the prior art, the method for packing
a catalyst after it is mixed and diluted with an inactive
20 material, the method for packing a plurality of composite
oxide-based catalysts having different occupation volumes in
such a manner that the volume gradually decreases, etc.,
have problems in that they are inefficient for commercial
use because the packing ratio of a catalyst varies depending
25 on the size, shape, specific gravity and density of the
catalyst and inactive material, even though the catalyst is
mixed and diluted with the inactive material at a correct
ratio and then the mixtme is packed into a reaction tube.
Additionally, the method for packing a catalyst by
30 controlling the catalytic activity through the control of
the occupation volume, sintering temperature and/or kind
and/or amount of alkali metal elements in the catalyst
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WO 2005/063673 PCT/KR2004/003433
having a specific composition can reduce the temperature of
a hot spot generated during the catalytic reaction, thereby
minimizing degradation of catalyst and side reactions.
However, the method is problematic in that the hot spot
5 still maintains high temperature.
Therefore, there is a continuous need for a method for
minimizing degradation of catalyst and side reactions caused
by extreme heat generation at a hot spot generated during
the catalytic reaction.
10
Brief Description of the Drawings
FIG. 1 is a schematic view showing the structure of a
reactor according to Example 2, including catalytic layers
and an inactive material layer packed therein.
16 FIG. 2 is a graph showing the temperature profile of a
catalyst bed at 310ºC in the first-step reaction producing
unsaturarated aldehyde as a main product.
Disclosurs of the Invention
20 It is an object of the present invention to provide a
method for producing unsaturated aldehydes and/or
unsaturated fatty acids with high yield in a stable manner
for a long time, the method including estimating the
position of a hot spot in a reaction tube and packing an
25 inactive material layer into the hot spot to reduce heat
generation at the hot spot, thereby facilitating heat
control and/or to disperse a temperature distribution toward
a reaction gas outlet.
According to an aspect of the present invention, there
30 is provided a method for producing unsaturated aldehydes or
unsaturated fatty acids from at least one compound selected
from the group consisting of propylene, propane,
6

WO 2005/063673 PCT/KR2004/003433
(meth) acrolein, isobutylene, t-butyl alcohol, methyl-t-butyl
ether and o-xylene by means of fixed-bed catalytic partial
oxidation in a shell-and-tube reactor, characterised in that
the reactor includes a reaction zone for producing
5 unsaturated aldehydes as a main product, the reaction zone
having an inactive material layer inserted into a position
where a hot spot is to be generated in a reaction tube.
According to another aspect of the present invention,
there is provided a shell-and-tube reactor that may be used
10 in a method for producing unsaturated aldehydes or
unsaturated fatty acids from at least one compound selected
from, the group consisting of propylene, propane,
(meth) acrolein, isobutylene, t-butyl alcohol, methyl-t-butyl
eather and o-xylene by means of fixed-bed catalytic partial
15 oxidation, characterised in that the reactor includes a
reaction zone for producing unsaturated aldehydes as a main
product, the reaction zone having an inactive material layer
inserted into a position where a hot spot is to be generated
in a reaction tube.
20 Hereinafter, the present invention will be explained
in detail.
According to the present invention, an inactive
meterial layer is formed at the position of a hot spot in
the reactor so that partial oxidation at the hot spot can be
25 prevented, thereby minimizing heat generation at the hot
spot and dispersing the temperature distribution, resulting
in minimization of degradation of catalyst and side
reactions.
As used herein, the term "hot spot" is referred to as
30 a point where a peak temperature is generated. For example,
a hot spot may be a point where an abnormally high
temperature is maintained due to excessive heat generation
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WO 2005/063673 PCT/KR2004/003433
or heat accumulation, in a catalytic bed in the reaction
tube of the first-step reaction zone for producing
unsaturated aldehydes as a main product.
A hot spot is formed by the reaction heat generated
5 during catalytic vapor phase oxidation. The position and
size of a hot spot are determined by many factors including
a reactant composition, space velocity and temperature of
heat transfer medium. Under constant processing conditions,
a hot spot has a constant position, and size. Therefore, the
10 position of a hot spot can be estimated by using a
simulation method, etc.
In general, each catalytic layer has at least one hot
spot. The hot spot in the first-step reaction zone may be
generated at the front part of the catalytic bed for the
15 first-step oxidation, enriched with a main reactant and
molecular oxygen. In addition, the hot spot may be generated
at the vicinity of the border of adjacent catalytic layers
having different activities, in the case of a reactor
structurs packed with two or more catalytic layers in the
20 first-step reaction zone.
According to the present invention, the position of a
hot spot and the temperature peak size of a hot spot are
quantitatively analyzed based on the temperature profile
(sec. FIG. 2) of a catalytic bed in a reaction tube. Then, a
25 predetermined height of an inactive material layer is
inserted into the temperature peak position where a hot spot
is generated so as to prevent partial oxidation at the hot
spot, thereby minimizing heat generation at the hot spot, and
dispersing a temperature distribution.
30 The reactors that may be used in the present invention
include a fixed-bed multi-tube reactor and a conical fixed-
bed multi-tube reactor. There is no particular limitation on
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WO 2005/063673 PCT/KR2004/003433
the shape of the reactor. In order to form a catalytic bed
needed for carrying out vapor phase partial oxidation, a
catalyst is packed in the reaction tube of a reactor, an
inactive material is packed at the position of a hot spot,
5 in one layer or two or more layers having different kinds
and sizes of inactive material, and then the catalyst is
further packed in the reaction tube.
In the case of the first-step reaction zone for
producing unsaturated aldehydes as a main product, a
10 catalytic bed may be packed in one layer having uniform
activity along the axial direction, or in two or more layers
whose catalytic activity gradually increases along the axial
direction, if necessary.
Preferably, the catalyst used in the vapor phase
15 partial oxidation for producing unsaturated aldehydes as a
main product is a metal oxide represented by the following
formulla 1:
1 (formula 1)
MoaAbBcCdOeEfFgOp
20 wherein Mo is molybdenum;
A is at least one element selected from the group
consisting of Bi and Cr;
B is at least one element selected from the group
consisting of Fe, Zn, Mn, Cu and Te;
25 C is at least one element selected from the group
consisting of Co, Rh and Ni;
D is at least one element selected from the group
consisting of W, Si, Al, Zr, Ti, Cr, Ag and Sn;
E is at least one element selected from the group
30 consisting of P, Te, As, B, Sb, Nb, Mn, Zn, Ce and Pb;
F is at least one element selected from the group
consisting of Na, K, Li, Rb, Cs, Ta, Ca, Mg, Sr, Ba and MgO;
9

WO 2005/063673 PCT/KR2004/003433
and
each of a, b, c, d, e, f and g represents the atomic
ratio of each element, with the proviso that when a=10, b is
a number of between 0.0l and 10, c is a number of between
5 0 01 and 10, d is a number of between 0.0 and 10, e is a
number of between 0.0 and 10, f is a number of between 0 and
20, g is a number of between 0 and 10, and h is a number
defined depending on the oxidation state of each of the
above elements.
10 The catalyst may have a cylindrical or a hollow
cylindrical shape, and there is no particular limitation in
shape of the catalyst. The catalyst preferably has an aspect
ratio (the ratio of length to diameter (outer diameter) ,
i.e., L/D) of between 1 and 1.3. More preferably, the ratio
15 of L/D equals 1.
The inactive material layer that may be used in the
present invention may be formed of an inactive material
alone or a mixture of an inactive material with a catalyst.
However, when a mixture of an inactive material with a
20 catalyst is used, the activity of the mixture should be
lower than that of a catalytic layer in the vicinity of a
hot spot. The volume ratio of the inactive material to the
catalyst in the inactive material layer is preferably 20-
l00%, and more preferably 80-100%.
25 The inactive material that may be used, in the present
invention is referred to as material inactive to a reaction
for producing unsaturated aldehydes and/or unsaturated acids
such as catalytic oxidation of propylene/isobutylene. Such
inactive materials include silica, alumina, silica/alumina,
30 zirconium oxide, titanium oxide, mixtures thereof, etc.
Although there is no particular limitation in shape of
the inactive material, the inactive material may have the
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WO 2005/063673 PCT/KR2004/003433
snape of a sphere, cylinder, ring, rod, plate, iron net and
mass with a suitable size. If necessary, mixtures of the
above shapes may be used.
When the inactive material has the shape of a sphere,
5 cylinder and ring, the diameter is preferably 2-10 mm, and
more preferably 5-8 mm. When, the inactive material has the
shape of a cylinder and ring, the ratio of length to
diameter (L/D) is preferably 1-1.3, and more preferably is
1. Preferably, the inactive material has the same or similar
10 shape and/or size as the catalyst.
At the point of a hot spot, the inactive material
layer is packed to the height of 0.1-1000 mm, preferably to
the height of 10-200 mm, in one or more, layers, preferably
in one or two layers. The position where the inactive
15 material layer is disposed in a reaction tube ranges
preferably 1-70% and more preferably 1-50% of the total
length of the whole catalytic bed in the reaction zone
producing unsaturated aldehyde as a main product, when
viewed from the reaction gas inlet toward the outlet.
20 It is preferable that the temperature at the hot spot
of a reactor is controlled by the inactive material layer
inserted into the hot spot, in such a manner that the
temperature of the hot spot is equal to or lower than
(reaction temperature + 55ºC). Accordingly, it is possible to
25 minimize volatilization of catalytically active components
and to inhibit side reactions caused by excessive heat,
thereby increassing the lifetime of a catalyst and producing
unsaturated aldehydes and unsaturated fatty acids with high
yield.
30 Vapor phase partial oxidation for producing aldehydes
as a main product in a reactor having an inactive layer at
the hot spot according to the present invention is suitably
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WO 2005/063673 PCT/KR2004/003433
carried out at a reaction temperature of 200-450ºC,
preferably 200-370ºC, under a reaction pressure of 0.1-10
arm, preferably 0.5-3 atm. For example, in order to perform
oxidation, a feed gas including 5-10 volume% of a feed
5 compound such as propylene, 13 volume% of oxygen, 5-60
volume% of water vapor and 20-80 volume% of an inert gas is
introduced onto a catalyst at a space velocity of 500-5000
br-1 (STP) .
10 Mode for Carrying Out the Invention
Reference will now be made in detail to the preferred
embodiments of the present invention. It is to be understood
that the following examples are illustrative only and the
present invention is not limited thereto.
15 Preparation Example 1
(Preparation of Catalyst)
2500 ml of distilled water was heated with stirring at
70-85ºC and 1000 g of ammonium molybdate was dissolved
therein to form solution (1) . To 400 ml or distilled water,
20 274g of bismith nitrate, 228 g of iron nitrate and 1.9 g of
potassium nitrate were added and mixed thoroughly. Next, 71
g of nitric acid was added to the mixture and dissolved
therein to form solution (2) , 513 g of cobalt nitrate was
dissolved in 200 ml of distilled water to form solution (3).
25 Solution (2) was mixed with solution (3) and the combined.
solution was further mixed with solution (1), while
maintaining the temperature of the solution at 40-60ºC, to
form a catalyst suspension.
The suspension obtained as described above was dried
30 to provide MO12Bi1.2Fe1.2Co4.5K0.04, which was pulverized into a
size of 150 pm or less. The pulverized catalyst powder was
mixed for 2 hours and formed into a cylindrical shape. The
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WO 2005/063673 PCT/KR2004/003433
formed catalyst had an outer diameter of 4.0-8.0 mm. Then,
the catalyst was baked at 500ºC for 5 hours under air to
check the catalytic activity.
Comparative Example l
5 To a stainless steel reactor having an inner diameter
of 1 inch and heated with molten nitrate,, alumina/silica as
an inactive material was packed to the height of 150 mm, and
then the catalyst obtained from Preparation Example 1 and
having a size of 5 mm (±0.2) was packed to the height of
10 2900 mm, when viewed from the reaction gas inlet toward the
outlet.
Example 1
To a stainless steel reactor having an inner diameter
of 1 inch and heated with molten nitrate, alumina/silica as
15 an inactive material was packed to the height of 150 mm, the
catalyst obtained from Preparation Example 1 and having a
size of 5 mm (±0.2) was packed to the height of 200 mm,
alumina/silica as an inactive material was packed to the
height of 100 mm at the point of a hot spot, and then the
20 catalyst obtained, from Preparation Example 1 and having a
size of 5 mm (±0-2) was further packed to the height of 2600
mm, when viewed from the reaction gas inlet toward the
outlet.
Comparative example 2
25 To a stainless steel reactor having an inner diameter
of 1 inch and heated with molten nitrate, alumina/silica as
an inactive material was packed to the height of 150 mm, the
catalyst obtained from Preparation Example 1 and having a
size of 7 mm (±0.2) was packed to the height of 800 mm, and
30 then the catalyst obtained from Preparation Example 1 and
having g size of 5 mm (±0.2) was further packed to the
height of 2100 mm, when viewed from the reaction gas inlet
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WO 2005/063673 PCT/KR2004/003433
toward the outlet.
Example 2
To a stainless steel reactor having an inner diameter
of 1 inch and heated with molten nitrate, alumina/silica as
5 an inactive material was packed to the height of 150 mm, the
catalyst obtained from Preparation Example 1 and having a
size of 7 mm(1±0.2) was packed to the height of 200 mm,
alumina/silica as an inactive material was packed to the
height of 100 mm at the point of a hot spot, and then the
10 catalyst obtained from Preparation Example 1 and having a
size of 7 mm (±0.2) was further packed to the height of 500
mm when viewed from the reaction gas inlet toward the
outlet. Further, the catalyst obtained from Preparation
Example 1 and having a size of 5 mm (±0.2) was packed to the
15 height of 100 mm, alumina/silica as an inactive material was
packed to the height of 100 mm at the point of a hot spot,
and then the catalyst obtained from Preparation Example 1
and having a size of 5 mm(±0.2) was packed to the height of
1900 mm.
20 Comparative Example 3
To a stainless steel reactor having an inner diameter
of 1 inch and heated with molten nitrate, alumina/silica as
an inactive material was packed to the height of 150 mm, the
catalyst obtained from Preparation Example 1 and having a
25 size of 7 mm (±0.2) was packed to the height of 800 mm, the
catalyst obtained from Preparation Example 1 and having a
size of 4.5 mm(±0.2) was packed to the height of 1100 mm,
and then the catalyst obtained from Preparation Example 1
and having a size of 5 mm(±0.2) was packed to the height of
30 1000 mm, when viewed from the reaction gas inlet toward the
outlet.
Example_ 3
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WO 2005/063673 PCT/KR2004/003433
To a stainless steel reactor having an inner diameter
of 1 inch and heated with molten nitrate, alumina/silica as
an inactive material was packed to the height of 150 mm, the
catalyst obtained from Preparation Example 1 and having a
5 size of 7 mm(±0.2) was packed to the height of 200 mm,
alumina/silica as an inactive material was packed to the
height of 100 mn at the point of a hot spot, and then the
catalyst obtained from preparation Example 1 and having a
size of 7 mm (±0.2) was further packed to the height of 500
10 mm, when viewed from the reaction gas inlet toward the
outlet. Next, the catalyst obtained from Preparation Example
1 and having a size of 4-5 mm (±0.2) was packed to the
height of 100 mm, alumina/silica as an inactive material was
packed to the height of 100 mm at the point of a hot spot,
15 and then the catalyst obtained from Preparation Example 1
and having a size at 4.5 mm (±0.2) was packed to the height
of 900 mm. Further the catalyst obtained from Preparation
Example 1 and having a size of 5 mm (±0.2) was packed to the
height of 100 mm, alumina/silica as an inactive material was
20 packed to the height of 100 mm at the point, of a hot spot,
and then the catalyst obtained from Preparation Example 1
and having a size of 5 mm(±0.2) was packed to the height of
800 mm.
Comparative Example 4
25 The same catalyst, inactive material and packing
heights as Comparative Example 3 were used to provide a
reactor, except that a stainless steel fixed-bed conical
multi-tube reactor was used instead of the stainless steel
reactor having an inner diameter of 1 inch.
30 Example 4
The same catalyst, inactive material and packing
heights as Example 3 were used to provide a reactor, except

WO 2005/063673 PCT/KR2004/003433
chat a stainless steel fixed-bed conical multi-tube reactor
was used instead of the stainless steel reactor having an
inner diameter of 1 inch.
Experimental Example: _Catalytic Activity Test.
5 The reactors packed with catalysts according to the
above Examples and Comparative Examples were used to perform
oxidation of propylene, thereby producing acrolein and
acrylic acid. The oxidation was carried out by introducing a
feed gas containing 1 volume% of propylene, 13 volume% of
10 oxygen, 8 volume% of water vapor and 13 volume% of inert gas
onto the catalyst at the reaction temperature of 320ºC,
under the reaction pressure of 0.7 atm, at the space
velocity of 1400 hr-1 (STP).
The results obtained from the above Examples and
15 Comparative Examples are shown in the following Table l.
In Table 1, the reactant (propylene) conversion ratio,
selectivity and yield are calculated based on the following
mathematical formulae 1 and 2.
(mathematical formula 1)
20 propylene conversion ratio(%) = [moles of reacted
propylene/males of supplied propylene] X 100
[mathematical formula 2]
yield (%) of acrolein + acxylic acid = [moles of
produced acrolein and acrylic acid/moles of supplied
25 propylene] X 100
[Table 1]

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WO 2005/063673 PCT/KR2004/003433

As can be seen from Table 1, reactors of Examples 1-4
including at least one layer of inactive material formed at
the point of a hot spot in the catalytic reaction zone
5 according to the present invention can provide excellent
prepylene conversion ratio and yield of a desired product as
well as a lower temperature in the point of heat generation.
Industrial Applicability
10 As can be seen from the foregoing, the present
invention provides a method for producing unsaturated
aldehydes and/or unsaturated fatty acids from at least one
compound selected from the group consisting of propylene,
propane, (meth) acrolein, isobutylene, t-butyl alcohol,
15 methyl-t-butyl ether and o-xylene, by means of fixed-bed
catalytic vapor phase partial oxidation with molecular
oxygen or molecular oxygen-containing gas in a shell-and-
tube heat exchange type reactor. According to the present
invention, it is possible to minimize the heat generation in
20 hot spots, to disperse a temperature distribution toward an
outlet, and thus to produce unsaturated aldehydes and
unsaturated fatty acids stably with high yield for a long
time, by virtue of at least one layer of inactive material
inserted at the point of a hot spot.
25 While this invention has been described in connection
with what is presently considered to be the most practical
and preferred embodiment, it is to be understood that the
17

WO 2005/063673 PCT/KR2004/003433
invention is not limited to the disclosed embodiment and the
drawings. On the contrary, it is intended to cover various
modifications and variations within the spirit and scope of
the appended claims.
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WO 2005/063673 PCT/KR2004/003433
Claims
1. A method for producing unsaturated aldehydes or
unsaturated fatty acids from, at least one compound selected
from the group consisting of propylene, propane,
5 (meth) acrolein, isobutylene, t-butyl alcohol, methyl-t-butyl
ether and o-xylene by means of fixed-bed catalytic partial
oxidation in a shell-and-tube reactor, characterized in that
the reactor includes a reaction zone for producing
unsaturated aldehydes as a main product, the reaction zone
10 having an inactive material layer inserted into a position
where a hot spot is to be generated in a reaction tube.
2. The method according to claim 1, wherein the
catalyst is a metal oxide catalyst represented by the
15 following formula 1:
[formula 1]
MoaAbBcCdDeEfFgOn
wherein Mo is molybdenum;
A is at least one element selected from the group
20 consisting of Bi and Cr;
B is at least one element selected from the group
consisting of Fe, Zn, Mn, Cu and Te;
C is at least one element selected from the group
consisting of Co, Rh and Ni;
25 D is at least one element selected from the group
consisting of W, Si, Al, Zr, Ti, Cr, Aq and Sn;
E is at least one element selected from the group
consisting o£ P, Te, As, B, Sb, Nb, Mn, Zn, Ce and Pb;
F is at least one element selected from the group
30 consisting of Wa, K, Li, Sb, Cs, Ta, Ca, Mg, Sr, Ba and MgO;
and
each of a, b, c, d, e, f and g represents the atomic
19

WO 2005/063673 PCT/KR2004/003433
RO/KR 25.02.2005
ratio of each element, with the proviso that when a=10, b is
a number of between 0.01 and 10, c is a number of between
0.01 and 10, d is a number of between 0,0 and 10, e is a
number of between 0.0 and 10, f is a number of between 0 and
5 20, g is a number of between 0 and 10, and h is a number
defined depending on the oxidation state of each of the
above elements.
3. The method according to claim l, wherein the
10 inactive, material layer is formed of an inactive material
alone or a mixture of an inactive material with a catalyst.
4. The method according to claim 3, wherein the
infective material is present in the inactive material layer
15 in a ratio of between 20% and 100% based on the volume of
the catalyst.
5. The method according to claim 1, wherein the
inactive material layer is packed to a height of between 0.1
20 mm land 1000 mm.
6. The method according to claim 3, wherein the
inactive material takes a spherical, cylindrical or ring
shape and has a diameter of between 2 mm and 10 mm.
25
7. The method according to claim l, wherein the
temperature of the hot spot is controlled in such a manner
that it is equal to or lower than (reaction temperature +
55ºC).
30
8. The method according to claim 1, wherein the
inactive material has the same size, shape or size and shape
20

WO 2005/063673 PCT/KR2004/003433
as the catalyst.
9. A shell-and-tube reactor that may be used in a
method for producing unsaturated aldehydes or unsaturated
5 fatty acids from at least one compound selected from the
group consisting of propylene, propane, (meth) acrolein,
isobutylene, t-butyl alcohol, methyl-t-butyl ether and o-
xylene by means of fixed-bed catalytic partial oxidation,
chcraeterized in that the reactor includes a reaction zone
10 for producing unsaturated aldehydes as a main product, the
reaction zone having an inactive material layer inserted
into a position where a hot spot is to be generated in a
reaction tube.
21

Diclosed is a method for producing unsaturated aldehydes or unsaturated fatty acids at least compound
selected from the group XXX of propylene propane (methylaceton isobutylene 1-butyl alchol methyl 1-poly ester andXXX
lene by means of fixed-bed catalyne XXX oxidation in a shall and tube reactor charecterized in that the reactor include reaction
zone for producing unsaturated zolehydes as XXX product the reaction zone having an inactive methanol layer inserted into a po-
sition where a hot spot is to the generated in a reactuion tube. A fixed bed shell and tube reactor for use in the above mehtod is also
disclosed. According to the present invention at least one layer of inactive material is packed at the point of a hot spot to control this
}hot spot temoarature efficiency thereby increasing the XXX of the catalyst and producing unsaturated aldehydes and unsatuarted
fetty acids with hugh yield.