A CATALYST COMPOSITION FOR GASEOUS PARTIAL OXIDATION
OF PROPYLENE AND METHOD FOR PREPARING THE SAME
Technical Field
The present invention relates to a method for preparing
a catalyst with high specific surface area to produce
acrolein and acrylic acid with high yield.
Background Art
Until now, many documents have proposed various methods
for producing acrolein, acrylic acid and other byproducts,
such as acetic acid, carbon monoxide and carbon dioxide, by
reacting propylene with oxygen-containing gas or air in the
presence of catalysts. Most of these catalysts have been
prepared and formed with the addition of ammonium nitrate,
cellulose, starch, polyvinyl alcohol, stearic acid, forming
aids, reinforcing agents, glass fiber, whisker, ethylene
glycol or polyethylene glycol in a forming process thereof.
In addition, many studies on the density, workability and
specific surface area of catalysts have been conducted, and
thus, many patent applications were filed in regard to the
technologies on catalyst preparations and additives.
Japanese Patent Laid-open Publication No. Sho 57-
119837, Japanese Patent Laid-open Publication No. Hei 1-
293389, Japanese Patent Laid-open Publication No. Hei 12-
169S1 and Japanese Patent Laid-open Publication No. 12-325795
disclose methods for preparing catalysts by adding an organic
polymer compound with a size of 0.01-10 µm to a catalyst
composition of Mo-Bi-Fe-Co-Ni, and forming the mixture into a
given shape, and then calcining the formed catalyst
composition. Examples of the organic polymer compound added
include methyl polymetacrylate, isobutyl polymetacrylate, and
polystyrene. Furthermore, Japanese Patent Laid-open
Publication No. Hei 13-48817 discloses a method for preparing
a catalyst with enhanced durability by the addition of
inorganic fiber and various whiskers to improve strength and
powdering of the catalyst, and a powder binder such as
ammonium nitrate, cellulose, starch, polyvinyl alcohol or
stearic acid to reproduce catalyst properties. However, a
need for studies on the preparation of catalysts with higher
activity and production yield still exists.
Studies on the preparation of acrolein and acrylic acid
using molybdenum-bismuth-cobalt-iron oxide catalysts have
been highly developed.
However, in order to prepare a catalyst exhibiting
higher activity and selectivity, there is a continued need
for the development of methods for preparing oxide catalysts
containing molybdenum-bismuth-cobalt-iron and other
transition metals.
Disclosure of the Invention
An object of the present invention is to develop a
catalyst capable of producing acrolein and acrylic acid at
high yields, and thus to provide a catalyst which exhibits
high activity for propylene oxidation, has high selectivity
to acrolein and acrylic acid, and allows stable operation of
a plant. To achieve this object, the present invention
provides a catalyst with high specific surface area prepared
by using a catalyst additive.
The present inventors have found that, in the
preparation of a catalyst which contains a composite metal
oxide as a catalytic active component and is used in
producing acrylic acid or acrolein by the vapor-phase
oxidation of propylene with oxygen-containing gas or air, the
use of a sublimable material, such as urea, melamine,
ammonium oxalate, methyl oxalate or naphthalene, as a
catalyst additive, can provide a catalyst with high specific
surface area.
On the basis of this finding, in one aspect, the
present invention provides a composition for catalyst
preparation comprising: 1) a composite metal oxide as a
catalytic active component; and 2) at least one catalyst
additive selected from the group consisting of sublimable
materials, including urea (NH2CONH2), melamine (C3H6N6) ,
ammonium oxalate (C2H8N2O4) , methyl oxalate (C4H6O4) and
naphthalene (C10H8) .
In another aspect, the present invention provides a
catalyst having fine pores formed by removing the catalyst
additive from the composition for catalyst preparation by a
calcining process, the catalyst additive being selected from
the group consisting of sublimable materials, including urea
(NH2CONH2), melamine (C3H6N6) , ammonium oxalate (C2H8N2O4) ,
methyl oxalate (C4H6O4) and naphthalene (C10H8) .
In still another aspect, the present invention provides
a method for preparing a catalyst containing a composite
metal oxide as a catalytic active component, the method
comprising the steps of:
a) preparing a catalyst suspension containing salt of
each metal component of the composite metal oxide for
catalytic active component;
b) drying the catalyst suspension and then crushing the
dried material to prepare a catalyst powder;
c) mixing the catalyst powder with at least one
catalyst additive selected from the - group consisting of
sublimable materials, including urea (NH2CONH2), melamine
(C3H5N6) , ammonium oxalate (C2H8N2O4) , methyl oxalate (C4H6O4)
and naphthalene (C10H8); and
d) calcining the mixture from the step c) .
In further another aspect, the present invention
provides a catalyst as well as a preparing method, thereof,
which comprises the steps of: adding at least one catalyst
additive selected from the group consisting of sublimable
materials, including urea (NH2CONH2) , melamine (C3H6N6) ,
ammonium oxalate (C2H8N2O4), methyl oxalate (C4H6O4) and
naphthalene (C10H8) to the catalytic active component
represented by the following formula 1 then mixing; forming
the mixture into a given shape; and calcining the formed
mixture:
[Formula 1]
MoaBibAcBdCeDfEgOh
wherein Mo is molybdenum;
Bi is bismuth;
A is an iron element;
B is at least one element selected from the group
consisting of Co and Ni;
C is at least one element selected from the group
consisting of W, Si, Al, Zr, Ti, Cr, Ag and Sn;
D is at least one element selected from the group
consisting of P, Te, As, B, Sb, Ce, Nb, Pb, Mn, Zn and Nb;
E is at least one element selected from the group
consisting of Na, K, Li, Rb, Cs, Ta, Ca and Mg;
a, b, c, d, e, f and g represent atomic ratio of the
respective elements, and
when a is 12, b is then 0.01-10, c is 0.01-10, d is
0.01-10, e is 0.01-10, f is 0.01-20 and g is 0.01-10, and h
is a numeral value depending on the oxidation state of each
of the elements.
The catalyst prepared using catalytic active component
of formula 1 can be used in producing acrolein and acrylic
acid by the vapor-phase contact oxidation of propylene.
Hereinafter, the present invention will be described in
detail.
The catalyst conventionally prepared for the production
of acrylic acid and acrolein, which consists of a composite
metal oxide, is known to have low specific surface area.
Because such a catalyst has low contact area with reactants
and thus has low catalytic activity, it is difficult to
achieve high preparation efficiency with this catalyst. To .
solve this problem, in the present invention, a sublimable
material, such as urea, melamine, ammonium oxalate, methyl
oxalate or naphthalene, was used to facilitate the control of
catalyst specific surface area and to achieve high catalyst
activity.
In the present invention, at least one catalyst
additive selected from the group consisting of sublimable
materials, including urea, melamine, ammonium oxalate, methyl
oxalate and naphthalene, is added to the catalytic active
component of formula 1 in the preparation of the catalyst,
which is used in a process of producing acrolein and acrylic
acid from, for example, oxygen-containing gas and propylene.
This can provide a catalyst with high activity as a result of
an increase in the specific surface area of the catalyst.
The sublimable material, such as urea, melamine,
ammonium oxalate, methyl oxalate or naphthalene, is a
material for controlling the surface area and fine pores of
the catalyst, because it takes a certain volume in the
composition for catalyst preparation and then is removed by a
drying or calcining process. The sublimable material
preferably has a size of 0.01-10 µm, and may be used in any
form, such as granular powder or liquid phase.
The sublimable material may be used at the amount of
0.1-30% by weight to the weight of the catalytic active
component of formula 1, and in view of the durability and
performance of the catalyst, it may preferably be used at the
amount of 0.1-20% by weight.
The sublimable material, such as urea, melamine,
ammonium oxalate, methyl oxalate or naphthalene, is an
organic material or organic amine consisting mainly of
oxygen, nitrogen, carbon and hydrogen, and is preferably in
the form of granule or powder at room temperature.
According to the present invention, the' composition for
catalyst preparation comprising: 1) a composite metal oxide
as a catalytic active component; and 2) a catalyst additive
selected from sublimable materials, including urea (NH2CONH2),
melamine (C3H6N6) , ammonium oxalate (C2H8N2O4), methyl oxalate
(C4H6O4) and naphthalene (C10H8); is preferably calcined at a
temperature of 400-500 °C for at least 5 hours to prepare a
calcined final catalyst.
The catalyst additive selected from sublimable
materials, including urea (NH2CONH2) , melamine (C3H6N6),
ammonium oxalate (C2H8N2O4), methyl oxalate (C4H6O4) and
naphthalene (C10H8), is removed from the composition at a
temperature below 250°C.
In addition to the above calcining step, a calcining
step as a pre-treatment may be additionally adopted. That is,
before the sublimable material, such as urea, melamine,
ammonium oxalate, methyl oxalate or naphthalene, is added to
the crushed catalyst powder, the crushed catalyst powder is
calcined at 180-250°C under an oxygen atmosphere for 3-5
hours. This pre-treatment step is conducted in order to
remove hygroscopic nitrate compounds before the catalyst
forming step of forming catalyst mixture into a given shape,
thus making good workability.
The catalyst powder to which the catalyst additive will
be added is crushed to a size of less than 150 µm for use.
The shape of the catalyst is not limited and may be any
shape, such as a cylinder, sphere, pellet, ring, shape, or the
like.
The catalyst prepared by the method of the present
invention can be used in the vapor-phase oxidation of
propylene according to a conventional method without specific
limitations.
Best Mode for Carrying Out the Invention
The present invention will now be described in detail
by the following examples and comparative examples. It is to
be understood, however, that these examples are provided by
way of illustration and nothing therein should be taken as a
limitation upon the scope of the present invention.
Comparative Example 1: Catalyst Preparation
1000 g of ammonium molybdenate was dissolved in 2500 ml
of distilled water with stirring and heating at 70°C to
prepare solution (1) . To 400 ml of distilled water, 228 g of
bismuth nitrate, 190.70 g of iron nitrate and 1.71 g of
potassium nitrate were added and mixed sufficiently, and then
71 g of nitric acid was added and dissolved in the mixture to
prepare solution (2) . 604.4 g of cobalt nitrate was dissolved
in 200 ml of distilled water to prepare solution (3) . The
solution (1) was mixed with the solution (3) with vigorous
stirring, to which the solution (2) was then added to prepare
a catalyst suspension. The suspension was dried in an
electric oven at 120°C for 12 hours, followed by crushing
into a size of less than 150 µm. The crushed catalyst powders
were mixed for 2 hours, formed into a shape of pellet, and
calcined at 450°C for 5 hours under an air atmosphere, then
examined for catalytic activities.
The prepared catalyst has the following composition:
MO12Bi1Fe1CO4.4KD.036 (Catalyst 1)
Example 1
A catalyst was prepared in the same manner as in
Comparative Example 1 except that 6% by weight of urea was
further added before forming the crushed catalyst powders
into a shape.
Example 2
A catalyst was prepared in the same manner as in
Comparative Example 1 except that 8% by weight of urea was
further added before forming the crushed catalyst powders
into a shape.
Example 3
A catalyst was prepared in the same manner as in
Comparative Example 1 except that 10% by weight of urea was
further added before forming the crushed catalyst powders
into a shape.
Example 4
A catalyst was prepared in the same manner as in
Comparative Example 1 except that 12% by weight of urea was
further added before forming the crushed catalyst powders
into a shape-
Example 5
A . catalyst was prepared in the same manner as in
Comparative Example 1 except that 6% by weight of naphthalene
was further added before forming the crushed catalyst powders
into a shape.
Example 6
A catalyst was prepared in the same manner as in
Comparative Example 1 except that 8% by weight of naphthalene
was further added before forming the crushed catalyst powders
into a shape.
Example 7
A catalyst was prepared in the same manner as in
Comparative Example 1 except that 10% by weight of
naphthalene was further added before forming the crushed
catalyst powders into a shape.
Example 8
A catalyst was prepared in the same manner as in •
Comparative Example 1 except that 12% by weight of
naphthalene was further added before forming the crushed
catalyst powders into a shape.
Comparative Exarople 2
1000 g of ammonium molybdenate was dissolved in 2500 ml
of distilled water with stirring and heating at 70 °c to
prepare solution (1) . To 400 ml of distilled water, 228 g of
bismuth nitrate, 190.70 g of iron nitrate, 1.71 g of
potassium nitrate and 62.25 g of aluminum chloride were added
and mixed sufficiently, and then 71 g of nitric acid was
added and dissolved in the mixture to prepare solution (2) .
604.4 g of cobalt nitrate was dissolved in 200 ml of
distilled water to prepare solution (3) . The solution (1) was
mixed with the solution (3) by vigorous stirring, to which
the solution (2) was then added to prepare a catalyst
suspension. The suspension was dried in an electric oven at
120 °C for 12 hours, followed by crushing into a size of less
than 150 µm. The crushed catalyst powders were mixed for 2
hours, formed into a shape of pellet, and calcined at 450 °C
for 5 hours under an air atmosphere, then examined for
catalytic activities.
The prepared catalyst has the following composition:
MO12Bi1Fe1CO4.4AL1KD.036 (Catalyst 2)
Example 9
A catalyst was prepared in the same manner as in
Comparative Example 2 except that 6% by weight of melamine
was further added before forming the crushed catalyst powders
into a shape.
Example 10
A catalyst was prepared in the same manner as in
Comparative Example 2 except that 8% by weight of melamine
was further added before forming the crushed catalyst powders
into a shape.
Example 11
A catalyst was prepared in the same manner as in
Comparative Example 2 except that 10% by weight of melamine
was further added before forming the crushed catalyst powders
into a shape.
Example 12
A catalyst was prepared in the same manner as in
Comparative Example 2 except that 12% by weight of melamine
was further added before forming the crushed catalyst powders
into a shape.
Comparative Example 3
1000 g of ammonium molybdenate was dissolved in 2500 ml
of distilled water with stirring and heating at 70 °C to
prepare solution (1). To 400 ml of distilled water, 228 g of
bismuth nitrate, 190.70 g of iron nitrate, 15 g of cerium
nitrate, 21 g of manganese nitrate and 1.71 g of potassium
nitrate were added and mixed sufficiently, and then 71. g of
nitric acid was added and dissolved in the mixture to prepare
solution (2) . 604.4 g of cobalt nitrate was dissolved in 200
ml of distilled water to prepare solution (3). The solution
(1) was mixed with the solution (3) by vigorous stirring, to
which the solution (2) was then added to prepare a catalyst
suspension. The suspension was dried in an electric oven at
120°C for 12 hours, followed by crushing into a size of less
than 150 µm. The crushed catalyst powders were mixed for 2
hours, formed into a shape of pellet, and calcined at 450oC
for 5 hours under an air atmosphere, then examined for
catalytic activities.
The prepared catalyst has the following composition:
MO12Bi1Fe1CO4.4KD.036Ce0.1 (Catalyst 3)
Example 13
A catalyst was prepared in the same manner as in
Comparative Example 3 except that 6% by weight of ammonium
oxalate was further added before forming the crushed catalyst
powders into a shape.
Example 14
A catalyst was prepared in the same manner as in
Comparative Example 3 except that 8% by weight of ammonium
oxalate was further added before forming the crushed catalyst
powders into a shape.
Example 15
A catalyst was prepared in the same manner as in
Comparative Example 3 except that 10% by weight of ammonium
oxalate was further added before forming the crushed catalyst
powders into a shape.
Example 16
A catalyst was prepared in the same manner as in
Comparative Example 4 except that 12% by weight of ammonium
oxalate was further added before forming the crushed catalyst
powders into a shape.
Comparative Example 4
1000 g of ammonium molybdenate was dissolved in 2500 ml
of distilled water with stirring and heating at 70 °C to
prepare solution (1) . To 400 ml of distilled water, 228 g of
bismuth nitrate, 190.70 g of iron nitrate, 149 g of nickel
nitrate and 1.71 g of potassium nitrate were added and mixed
sufficiently, and then 71 g of nitric acid was added and
dissolved in the mixture to prepare solution (2) . 321.56 g of
cobalt nitrate was dissolved in 200 ml of distilled water to
prepare solution (3) . The solution (1) was mixed with the
solution (3) by stirring, to which the solution (2) was then
added to prepare a catalyst suspension. The suspension was
dried in an electric oven at 120 °C for 12 hours, followed by
crushing into a size of less than 150 µm. The crushed
catalyst powders were mixed for 2 hours, formed into a shape
of pellet, and calcined at 450°C for 5 hours under an air
atmosphere, then examined for catalytic activities.
The prepared catalyst has the following composition:
MO12Bi1Fe1CO3Ni1.4K0.036 (Catalyst 4)
Example 17
A catalyst was prepared in the same manner as in
Comparative Example 4 except that 6% by weight of methyl
oxalate was further added before forming the crushed catalyst
powders into a shape.
Example 18
A catalyst was prepared in the same manner as in
Comparative Example 4 except that 8% by weight of methyl
oxalate was further added before forming the crushed catalyst
powders into a shape.
Example 19
A catalyst was prepared in the same manner as in
Comparative Example 4 except that 10% by weight of methyl
oxalate was further added before forming the crushed catalyst
powders into a shape.
Example 20
A catalyst was prepared in the same manner as in
Comparative Example 4 except that 12% by weight of methyl
oxalate was further added before forming the crushed catalyst
powders into a shape.
Test Example: Catalytic Activity Test
In order to measure the activity of the catalyst
prepared according to the method of the present invention,
the catalyst was formed into a pellet and placed into a
reactor, and the oxidation of propylene was performed in the
reactor to produce acrolein and acrylic acid. In the
production of acrolein and acrylic acid, reaction gas
comprising 1-10% by volume of propylene, 1-15% by volume of
oxygen, 5-60% by volume of water vapor and 20-80% by volume
of inert gas was introduced into the reactor and contacted
the catalyst at a reaction temperature of 200-370 °C and a
space velocity of 500-5000/hour (STP) under a reaction
pressure of 0.5-3 atm. The reaction test results for the
catalysts prepared in Examples and Comparative Examples are
given in Table 1 below.
Conversion ratio, selectivity and yield given in Table
1 were calculated by the following equations 1, 2 and 3,
respectively:
[Equation 1]
Propylene conversion (%) = (moles of reacted
propylene/moles of fed propylene) X 100
[Equation 2]
Acrolein selectivity (%) = (moles of produced
acrolein/moles of reacted propylene) X 100
[Equation 3]
Yield (%) = (moles of produced acrolein and acrylic
acid/moles of fed propylene) X 100
As can be seen from the foregoing, the addition of a
given amount of the sublimable material, such as urea
(NH2CONH2), melamine (C3H6N6), ammonium oxalate (C2H8N2O4),
methyl oxalate (C4H6O4) or naphthalene (C10H8), as a catalyst
additive, produced many fine pores in the catalyst. Thus, the
use of this catalyst in the vapor-phase oxidation of
propylene resulted in an increase in propylene conversion,
and an increase in the yield of acrolein and acrylic acid.
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
invention is not limited to the disclosed embodiment, but, on
the contrary, it is intended to cover various modifications
and variations within the spirit and scope of the appended
claims.
We claim :
1. A composition for catalyst preparation comprising:
1) a composite metal oxide represented by the following formula 1 as a catalytic
active component; and
2) a catalyst additive selected from sublimable materials wherein the catalyst
additive is selected from the group consisting of urea (NH2CONH2), melamine (C3H6N6),
ammonium oxalate (C2H8N2O4). methyl oxalate (C4H6O4) and naphthalene (C10H8).
[Formula 1]
MoaBibAcBdCeDfEgOh
wherein Mo is molybdenum;
Bi is bismuth;
A is an iron element;
B is at least one element selected from the group consisting of Co and Ni;
C is at least one element selected from the group consisting of W, Si, Al, Zr, Ti,
Cr, Ag and Sn;
D is at least one element selected from the group consisting of P, Te. As, B, Sb,
Ce, Nb. Pb, Mn, Zn and Nb;
E is at least one element selected from the group consisting of Na, K, Li, Rb, Cs,
Ta, Ca and Mg;
a, b, c, d, e, f and g represent the atomic ratio of the respective elements, and
when a is 12, b is then 0.01-10, c is 0.01-10, d is 0.01-10, e is 0.01-10, f is 0.01-
20 and g is 0.01-10; and h is a numeral value depending on the oxidation state of each of
the elements.
2. The composition as claimed in Claim 1, wherein the catalyst additive is in the
form of a granular powder with a size of 0.01-10 urn or a liquid.
3. The composition as claimed in Claim 1, wherein the catalyst additive is added
at the amount of 0.1-30% by weight to the weight of the catalyst active component of
formula 1.
4. A method for preparing a catalyst containing a composite metal oxide as a
catalytic active component, the method comprising the steps of:
a) preparing a catalyst suspension containing salt of each metal components of
the composite metal oxide for the catalytic active component;
b) drying the catalyst suspension and then crushing the dried material to prepare a
catalyst powder;
c) mixing the catalyst powder with a catalyst additive selected from sublimable
materials wherein the catalyst additive is selected from the group consisting of urea
(NH2CONH2), melamine (C3H6N6), ammonium oxalate (C2H8N2O4), methyl oxalate
(C4H6O4) and naphthalene (C10H8); and
d) calcining the mixture from the step c).
5. The method of Claim 6, which comprises the steps of:
a) preparing a catalyst suspension containing a catalytic component represented
by the following formula 1;
b) drying the catalyst suspension and then crushing the dried material into a
catalyst powder with a size of less than 150;
c) mixing the crushed catalyst powder with a catalyst additive selected from
sublimable materials wherein the catalyst additive is selected from the group consisting of
urea (NH2CONH2), melamine (C3H6N6), ammonium oxalate (C2H8N2O4), methyl oxalate
(C4H6O4) and naphthalene (C10H8); and
d) calcining the mixture from the step c) at a temperature of 400-500 °C under an
air atmosphere for at least 5 hours:
[Formula 1]
MoaBibAcBdCeDfEgOh
wherein Mo is molybdenum;
Bi is bismuth;
A is an iron element;
B is at least one element selected from the group consisting of Co and Ni;
C is at least one element selected from the group consisting of W, Si, Al, Zr, Ti,
Cr, Ag and Sn;
D is at least one element selected from the group consisting of P, Te, As, B, Sb,
Ce, Nb, Pb, Mn, Zn and Nb;
E is at least one element selected from the group consisting of Na, K, Li, Rb, Cs,
Ta, Ca and Mg;
a, b, c, d, e, f and g represent the atomic ratio of the respective elements, and
when a is 12, b is then 0.01-10, c is 0.01-10, d is 0.01-10, e is 0.01-10, f is 0.01-
20 and g is 0.01-10; and h is a numeral value depending on the oxidation state of each of
the elements.
6. The method as claimed in Claim 7, which optionally comprises, between the
steps b) and c), a step of calcining the crushed catalyst powder at a temperature of 180-
250 °C for 3-5 hours under an oxygen atmosphere.
7. The method as claimed in Claim 6 or 7, wherein the catalyst additive is in the
form of a granular powder with a size of 0.01-10 µm or a liquid.
8. The method as claimed in Claim 7, wherein the catalyst additive is added at
the amount of 0.1-30% by weight to the weight of the catalytic active component of
formula 1.
9. A catalyst having fine pores formed by removing the catalyst additive from the
composition for catalyst preparation as claimed in any one of Claims 1, 4, and 5 by a
calcining process.

The invention discloses a composition for catalyst preparation comprising:
1) a composite metal oxide represented by the following formula 1 as a catalytic
active component; and
2) a catalyst additive selected from sublimable materials wherein the catalyst
additive is selected from the group consisting of urea (NH2CONH2), melamine (C3H6N6),
ammonium oxalate (C2H8N2O4), methyl oxalate (C4H6O4) and naphthalene (C10H8).
[Formula 1]
MoaBibAcBdCeDfEgOh
wherein Mo is molybdenum;
Bi is bismuth;
A is an iron element;
B is at least one element selected from the group consisting of Co and Ni;
C is at least one element selected from the group consisting of W, Si, Al, Zr, Ti,
Cr, Ag and Sn;
D is at least one element selected from the group consisting of P, Te, As, B, Sb,
Ce,Nb, Pb, Mn, Zn and Nb;
E is at least one element selected from the group consisting of Na, K, Li, Rb, Cs,
Ta, Ca and Mg;
a, b, c, d, e, f and g represent the atomic ratio of the respective elements, and
when a is 12, b is then 0.01-10, c is 0.01-10, d is 0.01-10, e is 0.01-10, f is 0.01-20 and g
is 0.01-10; and h is a numeral value depending on the oxidation state of each of the
elements.
The invention is also for method of preparing said catalyst.