Title of Invention: Catalyst for ammoxidation of propylene, method for preparing same, and method for ammoxidation of propylene using same
technical field
[One]
Cross-Citation with Related Application(s)
[2]
This application claims the benefit of priority based on Korean Patent Application No. 10-2019-0121172 on September 30, 2019 and Korean Patent Application No. 10-2020-0124245 on September 24, 2020, All content disclosed in the literature is incorporated as a part of this specification.
[3]
The present invention relates to a catalyst for ammoxidation of propylene, a method for preparing the same, and a method for ammoxidation of propylene using the same.
background
[4]
The ammoxidation process of propylene is based on the reduction reaction of ammonia and propylene and the mechanism of reoxidation by oxygen, the conversion of the reactant (ie propylene), and the selectivity of the reaction product (ie acrylonitrile) And catalysts of various compositions to increase the yield have been studied.
[5]
Specifically, since Mo (molybdenum) -Bi (bismuth) oxide catalysts have been proposed, catalysts to which metals having various oxidation states are added have been studied in order to increase their catalytic activity and stability. As a result, depending on the type or amount of added metal, the yield of acrylonitrile is improved compared to the initial study.
[6]
However, despite the diversification of the catalyst composition, studies on the structure and physical properties thereof are lacking, and the conversion rate of the reactant (ie, propylene) and the selectivity of the reaction product (ie, acrylonitrile) during ammoxidation of propylene are remarkable. There was a limit to how high it could be.
[7]
Specifically, it is common to obtain a catalyst having a secondary particle structure in which metal oxide particles and silica particles are aggregated by co-precipitating a metal precursor of a desired composition and nano silica sol, spray drying, and calcining.
[8]
However, the catalyst having the secondary particle structure inevitably has high crystallinity during the spray drying process during the manufacturing process. As such, a catalyst having high crystallinity may be easily broken or broken by a high temperature applied during the reaction, and Mo or the like may be eluted from the inside to the surface, thereby deteriorating catalyst performance.
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[9]
The present invention is to provide a catalyst for the ammoxidation of propylene while suppressing the elution of Mo during the ammoxidation reaction of propylene, the catalytic activity is maintained at a high level.
means of solving the problem
[10]
Specifically, in one embodiment of the present invention, there is provided a catalyst for ammoxidation of propylene, which exhibits high activity for the ammoxidation reaction of propylene and has a high content of an amorphous phase.
Effects of the Invention
[11]
The catalyst of one embodiment has a high content of an amorphous phase while exhibiting high activity for the ammoxidation reaction of propylene, so that the catalytic activity can be maintained at a high level while Mo elution is suppressed during the ammoxidation reaction of propylene.
[12]
Therefore, by using the catalyst of one embodiment, acrylonitrile can be prepared in a higher yield while converting propylene at a higher ratio.
Brief description of the drawing
[13]
1 schematically shows a catalyst prepared using a spray drying method.
[14]
2 schematically shows the catalyst according to the embodiment.
[15]
3 shows the results of XRD analysis of the catalyst of an embodiment to be described later.
[16]
4 shows the results of XRD analysis of the catalyst of a comparative example to be described later.
Modes for carrying out the invention
[17]
Since the present invention can apply various transformations and can have various embodiments, specific embodiments will be illustrated and described in detail. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the present invention, if it is determined that a detailed description of a related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.
[18]
In addition, terms including ordinal numbers such as first, second, etc. to be used below may be used to describe various elements, but the elements are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.
[19]
The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It is to be understood that this does not preclude the possibility of addition or existence of numbers, steps, operations, components, parts, or combinations thereof.
[20]
Hereinafter, the catalyst for ammoxidation of propylene of the embodiment will be described in detail with reference to the drawings.
[21]
Catalyst for ammoxidation of propylene
[22]
In one embodiment of the present invention,
[23]
and a metal oxide represented by the following formula (1)
[24]
In X-ray diffraction analysis by Cu Cα, the first peak with intensity A appears within the range of 2θ of 26.3±0.5°, and the second peak with intensity of B appears within the range of 2θ of 28.3±0.5°,
[25]
The intensity ratio (A/B) of the first peak to the second peak is 1.5 or more,
[26]
A catalyst for the ammoxidation of propylene is provided:
[27]
[Formula 1]
[28]

[29]
In Formula 1,
[30]
A and B are different and are each independently one or more elements of Ni, Mn, Co, Zn, Mg, Ca, and Ba;
[31]
C is one or more of Li, Na, K, Rb, and Cs,
[32]
D is one or more of Cr, W, B, Al, Ca, and V,
[33]
Wherein a to f, x, and y are mole fractions of atoms or groups of atoms,
[34]
a is 0.1 to 7, b is 0.1 to 7, with the proviso that the sum of a and b is 0.1 to 7,
[35]
c is 0.1 to 10, d is 0.01 to 5, e is 0.1 to 10, f is 0 to 10,
[36]
x is 11 to 14, and y is a value that can be determined by the respective oxidation numbers of Mo, Bi, Fe, A, B, C, and D.
[37]
As mentioned above, as a catalyst for ammoxidation of propylene, a catalyst having a secondary particle structure prepared through co-precipitation and spray drying of a metal precursor and a nano silica sol is known.
[38]
The catalyst having the secondary particle structure has a problem in that the metal oxide particles are uniformly distributed inside and outside but hardly contain pores, so the adsorption amount of the reactant per unit volume is small and the reaction activity is low.
[39]
On the other hand, the catalyst having the secondary particle structure inevitably has high crystallinity during the spray drying process during the manufacturing process. As such, a catalyst having high crystallinity may be easily broken or broken by a high temperature applied during the reaction, and Mo or the like may be eluted from the inside to the surface, thereby deteriorating catalyst performance.
[40]
On the other hand, the catalyst of one embodiment has a high content of an amorphous phase while exhibiting high activity for the ammoxidation reaction of propylene, and while Mo elution during the ammoxidation reaction of propylene is suppressed, the catalytic activity can be maintained at a high level. .
[41]
Here, the amorphous phase while exhibiting high activity for the ammoxidation reaction of propylene may be a complex oxide phase of molybdenum (Mo) and a dissimilar metal, for example, a CoMoO 4 phase.
[42]
Specifically, in X-ray diffraction (XRD) analysis of the catalyst of the one embodiment, the first peak with intensity B appears within the range of 2θ of 26.3±0.5°, and the intensity within the range of 2θ of 28.3±0.5° A second peak with is B may appear.
[43]
Here, the first peak may appear by a complex oxide phase of molybdenum (Mo) and a different metal, for example, a CoMoO 4 phase. In addition, the second peak may appear by a molybdenum (Mo) oxide phase, that is, a MoO 3 phase.
[44]
The complex oxide phase of molybdenum (Mo) and a dissimilar metal exhibits activity against propylene ammoxidation, whereas the MoO 3 phase has no activity against propylene ammoxidation.
[45]
The catalyst of the secondary particle structure is prepared from a slurry in which silica sol and a metal oxide precursor are non-uniformly mixed, so that the content of the MoO 3 phase, which is an inactive phase, is relatively high, and the intensity ratio of the first peak to the second peak ( A/B) may be less than 1.5. Accordingly, Mo elution may occur during the ammoxidation reaction of propylene, and catalyst activity may be reduced.
[46]
On the other hand, in the catalyst of one embodiment, the content of the complex oxide phase of the heterogeneous metal as the active phase is relatively high, and the intensity ratio (A/B) of the first peak to the second peak is 1.5 or more, Specifically, it may be 2.0 or more, more specifically 2.5 or more, such as 3.0 or more.
[47]
Although a more detailed description will be given later, the catalyst of one embodiment may be prepared using an impregnation method. When a transparent solution in a very uniform state is supported on silica, the probability that the MoO 3 phase is formed alone is very low because the metal components exist in a well-bonded state .
[48]
In particular, since the large surface area of ​​the carrier itself is utilized, the dispersibility of active phases such as CoMoO 4 as well as FeMoO 3 and Bi 2 MoO 6 is greatly improved. Although the XRD peak intensity tends to decrease when the dispersibility is improved, the XRD pattern is formed in a state in which the peak of CoMoO 4 is significantly developed because the amount of Mo and Co added to form the metal oxide are large in the embodiment. can be
[49]
Accordingly, the catalyst of one embodiment, compared to the catalyst of the secondary particle structure, while Mo elution during the ammoxidation reaction of propylene is suppressed, the catalytic activity may be maintained at a high level.
[50]
On the other hand, in a catalyst that does not contain a heterogeneous metal other than Bi, for example, a catalyst containing only Mo and Bi as a metal component, a complex oxide phase of molybdenum (Mo) and a heterogeneous metal cannot be formed, and thus XRD The first peak cannot be seen in the analysis.
[51]
In other words, since the catalyst that does not contain a heterogeneous metal other than Bi includes only the inactive phase and the crystalline MoO 3 phase, Mo elution occurs during the ammoxidation reaction of propylene, and the catalytic activity may be reduced.
[52]
Hereinafter, the catalyst of the embodiment will be described in detail.
[53]
D50 particle size, pore volume and BET specific surface area of ​​catalyst
[54]
The catalyst of one embodiment may include a plurality of bulky pores to provide not only an external surface area but also an effective surface area in which the pores can participate in the reaction.
[55]
Specifically, the catalyst of the embodiment may have a D50 particle diameter of 10 to 300 μm, including pores having a volume of 0.3 to 1.3 cm 3 /g, and a BET specific surface area of ​​50 to 300 m 2 /g.
[56]
The BET specific surface area and pore volume provided by the catalyst of one embodiment are improved compared to the catalyst of the secondary particle structure, and thus, while converting propylene at a higher rate, acrylonitrile with higher selectivity and yield can be obtained.
[57]
Within the range presented above, as the pore volume included in the catalyst of the embodiment increases, the BET specific surface area of ​​the catalyst including the same may also increase. However, when the pore volume included in the catalyst of the one embodiment is excessively large, the content of the metal oxide may be relatively decreased, so that the catalytic activity may decrease.
[58]
Accordingly, it is possible to control the BET specific surface area and pore volume, etc., by comprehensively considering the desired properties as the catalyst of the embodiment.
[59]
For example, in the catalyst of one embodiment, the lower limit of the D50 particle size is 10 µm or more, 20 µm or more, 30 µm or more, or 45 µm or more, and the upper limit is 300 µm or less, 280 µm or less, 260 µm or less, 240 µm or less , 220 µm or less, or 200 µm or less.
[60]
In addition, the catalyst of one embodiment has a pore volume of 0.3 cm 3 /g or more, 0.35 cm 3 /g or more, 0.4 cm 3 /g or more, 0.45 cm 3 /g or more, or 0.5 cm 3 /g or more, and 1.3 cm 3 /g or less, 1.2 cm 3 /g or less, 1.1 cm 3 /g or less, and 1.0 cm 3 /g or less.
[61]
In addition, the catalyst of one embodiment is 50 m 2 /g or more, 70 m 2 /g or more, 90 m 2 /g or more, 110 m 2 /g or more, or 120 m 2 /g while 300 m 2 /g It may have a BET specific surface area of 270 m 2 /g or less, 240 m 2 /g or less, 210 m 2 /g or less, or 180 m 2 /g or less.
[62]
metal oxide
[63]
On the other hand, even if it has the same structure as the catalyst of the one embodiment, if the types and contents of the components constituting the metal oxide do not satisfy Formula 1 above, the active point of the catalyst insufficient or too dense for ammoxidation of propylene is formed can be
[64]
Accordingly, the type and content constituting the metal oxide needs to satisfy Chemical Formula 1 above. For example, the metal oxide may be one represented by the following Chemical Formula 1-1, and due to the synergistic effect of the metal components included therein, it may be advantageous to increase the active point for the ammoxidation reaction of propylene:
[65]
[Formula 1-1]
[66]

[67]
In Formula 1-1, the definitions of x, a to e, and y are the same as described above.
[68]
If you want to directly measure the metal oxide composition and content, it can be measured using measuring equipment such as ICP (Inductively Coupled Plasma, Inductively Coupled Plasma).
[69]
catalyst structure
[70]
As mentioned above, a commonly known catalyst for ammoxidation of propylene is prepared through co-precipitation and spray drying, and is provided as a secondary particle structure in which metal oxide nanoparticles and silica nanoparticles are aggregated (FIG. 1).
[71]
This is because, instead of uniformly distributed metal oxide particles inside and outside, the site that can participate in the ammoxidation reaction of propylene is limited to the outer surface portion (that is, the surface of secondary particles), and provides a small surface area, During the ammoxidation reaction, the amount of ammonia desorbed from the catalyst surface is large.
[72]
On the other hand, the catalyst of the exemplary embodiment may be prepared by an impregnation method and provided in a structure in which a metal oxide is supported on a silica carrier ( FIG. 2 ).
[73]
For example, the silica carrier may be immersed in a metal precursor solution prepared to satisfy a desired stoichiometric molar ratio of the metal oxide, and the metal precursor solution may be impregnated in the silica carrier.
[74]
Thereafter, when the solvent (ie, water) is removed through the drying process, the metal precursor remains on the pore wall of the silica carrier, and as the metal precursor is oxidized in the firing process, a film continuously coating the pore wall of the silica carrier can be formed. have.
[75]
The catalyst of one embodiment prepared as described above may further include a silica carrier supporting the metal oxide.
[76]
In this case, the catalyst of one embodiment may include a silica carrier including a second pore; an inner coating layer continuously coating the wall surfaces of the second pores and including the metal oxide represented by Chemical Formula 1; and a first pore located inside the second pore and occupying an empty space excluding the inner coating layer.
[77]
The catalyst having the above structure may have superior durability than a catalyst prepared with the same composition through co-precipitation and spray drying, even if a classification process is not performed as a post-processing after preparation.
[78]
In addition, by evenly supporting the metal oxide in the internal pores of the silica carrier, the site that can participate in the ammoxidation reaction of propylene extends not only to the external surface part (that is, the surface of the catalyst) but also to its internal surface (pores). have.
[79]
Specifically, the catalyst of one embodiment may have an egg-shell structure.
[80]
For this purpose, as the silica carrier, a non-porous core portion; and a porous shell portion located on the surface of the non-porous core and including the second pores; may be used.
[81]
More specifically, the porous shell includes a concave portion and a convex portion of the surface, and the concave portion is formed by opening the second pores to the surface of the porous shell. may be formed.
[82]
Accordingly, the catalyst of one embodiment may include a coating layer that continuously coats the concave and convex portions of the porous shell and includes a metal oxide represented by Chemical Formula 1; and a first pore occupying an empty space excluding the coating layer in the main portion of the silica carrier.
[83]
The catalyst structure of the embodiment may be confirmed through an electron microscope such as a scanning electron microscope (SEM).
[84]
Weight ratio of metal oxide:silica carrier
[85]
When the catalyst of one embodiment further includes the silica carrier, the weight ratio of the metal oxide and the silica carrier is 10:90 to 15:95, specifically 20:80 to 50:50, such as 15:85 to 35 :65 (metal oxide: silica carrier).
[86]
Within this range, the catalyst of one embodiment may have high selectivity of acrylonitrile with high activity.
[87]
If you want to directly measure the weight ratio of the metal oxide and the silica carrier, it can be measured using a measuring device such as ICP (Inductively Coupled Plasma, Inductively Coupled Plasma).
[88]
Method for preparing a catalyst for ammoxidation of propylene
[89]
In another embodiment of the present invention, preparing a first precursor solution comprising a Mo precursor,
[90]
Fe precursor; and preparing a second precursor solution comprising a precursor of at least one of Ni, Mn, Co, Zn, Mg, Ca, and Ba;
[91]
Bi precursor; a precursor of at least one of Ni, Mn, Co, Zn, Mg, Ca, and Ba different from the second precursor solution; and preparing a third precursor solution comprising a precursor of at least one of Li, Na, K, Rb, and Cs;
[92]
mixing the first to third precursor solutions so that the molar ratio of the metal satisfies the stoichiometric molar ratio of the following Chemical Formula 1;
[93]
Supporting the silica carrier in a mixture of the first to third precursor solutions;
[94]
drying the silica carrier on which the mixture of the first to third precursor solutions is supported, and
[95]
There is provided a method comprising calcining the dried material:
[96]
[Formula 1]
[97]

[98]
Definitions of x, a to e, and y in Formula 1 are the same as described above.
[99]
The preparation method of the embodiment corresponds to the method for preparing the catalyst of the embodiment described above using the impregnation method.
[100]
Hereinafter, descriptions overlapping with the above will be omitted, and the manufacturing method of the embodiment will be described step by step.
[101]
Process for preparing the first aqueous precursor solution
[102]
The step of preparing the first precursor solution may be a step of preparing an aqueous solution containing water and a Mo precursor by dissolving the Mo precursor in water at a temperature of 50 to 90 °C.
[103]
In the step of preparing the first aqueous precursor solution, an additive including citric acid, oxalic acid, or a mixture thereof may be used.
[104]
In a catalyst manufacturing process using co-precipitation and spray drying, the additive functions as a strength modifier. However, in the exemplary embodiment, the additive makes the first precursor solution transparent, so that a mixture precursor in a completely dissolved state can be prepared.
[105]
When the additive is added, the weight ratio of the molybdenum precursor and the additive may satisfy 1:0.1 to 1:1, specifically 1:0.2 to 1:0.7, and the solubility of the molybdenum precursor increases within this range. can, but is not limited thereto.
[106]
Manufacturing process of the second precursor solution
[107]
The step of preparing the second precursor solution, in water at 20 to 50 ℃, Fe precursor; and dissolving a second precursor including at least one of Ni, Mn, Co, Zn, Mg, Ca, and Ba. Optionally, a precursor further comprising a D precursor (D=one or more of Cr, W, B, Al, Ca, and V) may be further dissolved.
[108]
Here, the type and compounding amount of the precursor may be selected in consideration of the composition of the metal oxide in the final catalyst.
[109]
For example, an aqueous solution including water, an Fe precursor, and a Co precursor may be prepared in consideration of the metal oxide composition satisfying Chemical Formula 1-1.
[110]
Manufacturing process of the third precursor solution
[111]
The preparing of the third precursor solution comprises: a Bi precursor in nitric acid at 20 to 50 °C; a precursor of at least one of Ni, Mn, Co, Zn, Mg, Ca, and Ba different from the second precursor solution; and dissolving a precursor of at least one of Li, Na, K, Rb, and Cs.
[112]
Here too, the type and compounding amount of the precursor may be selected in consideration of the composition of the metal oxide in the final catalyst.
[113]
For example, a solution including nitric acid, a Bi precursor, a Ni precursor, and a K precursor may be prepared in consideration of the metal oxide composition satisfying Chemical Formula 1-1.
[114]
Mixing process of precursor solution
[115]
Processes of preparing the first to third precursor solutions are each independent, and the manufacturing order is not limited.
[116]
However, in consideration of the characteristics of each metal, the mixing of the first to third precursor solutions includes mixing the second and third precursor solutions, and a mixture of the second and third precursor solutions. It may include the step of dropping the first precursor solution.
[117]
In addition, when mixing the first to third precursor solutions, the mixing ratio may be controlled so that the molar ratio of metals satisfies the stoichiometric molar ratio of Chemical Formula 1, specifically, Chemical Formula 1-1.
[118]
Supporting process of precursor mixture solution
[119]
After preparing a mixture of the first to third precursor solutions, they may be supported on a silica carrier.
[120]
Here , silica ( _ SiO 2 ) The particles may be added to the mixture of the first to third precursor solutions and mixed, so that the mixture of the first to third precursor solutions is supported in the pores of the silica carrier.
[121]
Specifically, the step of supporting the mixture of the first to third precursor solutions on the silica carrier may include first mixing the silica carrier and the first to third precursor solutions within a temperature range of 20 to 30°C. and second mixing of the first mixture within a temperature range of 70 to 90° C., while the first and second mixing times may each independently be 1 to 3 hours.
[122]
However, this is only an example, and it is not particularly limited as long as the conditions allow the mixture of the first to third precursor solutions to be sufficiently supported on the silica carrier.
[123]
Drying and firing process
[124]
Thereafter, the silica carrier on which the mixture of the first to third precursor solutions is supported is dried at a temperature of 100 to 120° C. for 5 to 12 hours, and then calcined within a temperature range of 500 to 700° C. for 1 to 6 hours. and finally a catalyst can be obtained.
[125]
However, each condition of the drying and firing is only an example, and it is sufficient if the solvent is sufficiently removed from the pores of the carrier and the conditions capable of oxidizing the metal precursor are sufficient.
[126]
The structure of the catalyst thus formed is as described above.
[127]
Method for ammoxidation of propylene
[128]
In another embodiment of the present invention, in a reactor, there is provided a method for ammoxidation of propylene, comprising the step of reacting propylene and ammonia in the presence of the catalyst of the embodiment described above.
[129]
The catalyst of one embodiment has high activity and high temperature stability, and may be used for ammoxidation of propylene to increase propylene conversion, acrylonitrile selectivity, and yield.
[130]
For matters other than the catalyst of the embodiment, reference may be made to matters generally known in the art, and further detailed description will be omitted.
[131]
Hereinafter, embodiments of the present invention will be described in more detail in the following examples. However, the following examples are only illustrative of embodiments of the invention, and the content of the present invention is not limited by the following examples.
[132]
Example 1
[133]
(1) Preparation process of precursor solution
[134]
Mo precursor ((NH 4 ) 6 Mo 7 O 24 ) 4.24 g was dissolved in water at 85 ° C., and 3 g of oxalic acid or citric acid was added thereto to prepare a Mo precursor solution.
[135]
Independently, by dissolving 2.5 g of a Fe precursor (Fe(NO 3 ) 2 ·9H 2 O) and 3.5 g of a Co precursor (Co(NO 3 ) 2 ·6H 2 O) in water at room temperature, Fe and Co precursors A mixed solution was prepared.
[136]
Also independently, in a mixture of 1.46 g of Bi precursor (Bi(NO 3 ) 3 ·5H 2 O), 0.58 g of Ni precursor (Ni(NO 3 ) 2 ·6H 2 O), and 0.2 g of K precursor (KNO 3 ) By adding 2 g of nitric acid, a Bi, Ni, and K precursor mixed solution was prepared.
[137]
After mixing the Fe and Co precursor mixed solution and the Bi, Ni, and K precursor mixed solution with stirring, it is added dropwise to the Mo precursor solution to mix Mo, Bi, Fe, Ni, Co and K precursors A solution was obtained.
[138]
In the precursor mixed solution, the total amount of water is 45 g.
[139]
(2) Supporting process of precursor solution in silica carrier (using impregnation method)
[140]
Silica (SiO 2 ) having a particle size of 50-150 μm, a pore size of 10-25 nm, a pore volume of 1-3 cm 3 /g according to nitrogen adsorption method, and a BET specific surface area of ​​500-600 m 2 /g ) particles were used as carriers.
[141]
13 g of the silica carrier was added to the Mo, Bi, Fe, Ni, Co and K precursor mixed solution, and the Mo, The Bi, Fe, Ni, Co, and K precursor mixed solution was sufficiently supported.
[142]
(3) Manufacturing process of a catalyst in which a metal oxide is supported in a silica carrier
[143]
After that, the silica carrier on which the Mo, Bi, Fe, Ni, Co, and K precursor mixture solution is supported is recovered, dried in an oven at 110 ° C. for 12 hours, and maintained at a temperature of 580 ° C. in a nitrogen atmosphere tubular kiln 6 By heat treatment for a period of time, the catalyst of Example 1 in which 25 wt% of a metal oxide (however, the mole fraction of Mo in the metal oxide is 12) was supported was obtained.
[144]
(4) Ammoxidation process of propylene
[145]
In order to activate the catalyst, 0.2 g of the catalyst of Example 1 was filled in the reactor in which 0.05 g of quartz wool was filled.
[146]
As such, the internal pressure of the reactor filled with the quartz fiber and the catalyst was maintained at normal pressure (1 atm), and while the internal temperature of the reactor was increased at a temperature increase rate of 5 ° C., nitrogen and ammonia gas were flowed as a pretreatment process. Accordingly, the internal temperature of the reactor was made to reach 400° C., which is the temperature at which the ammoxidation reaction is possible, so that sufficient pretreatment was performed.
[147]
In this way, air was supplied along with propylene and ammonia as reactants to the reactor in which the pretreatment was completed, and the ammoxidation process of propylene was performed. At this time, the supply amount of the reactant is configured to have a volume ratio of propylene:ammonia:air=1:1.1:2=1.5 to 1:4:3, and the total weight hourly space velocity (WHSV) of propylene, ammonia, and air ) was set to 1 h -1 .　
[148]
After completion of the ammoxidation reaction, the product was recovered and analyzed using various equipment to confirm whether acrylonitrile was well produced.
[149]
The analysis method, analysis result, etc. will be described in detail in the experimental examples to be described later.
[150]
Examples 2 to 4
[151]
(1) Catalyst manufacturing process (using impregnation method)
[152]
A precursor solution was prepared according to the composition shown in Table 1, and the silica carrier shown in Table 2 was used, and the catalysts of Examples 2 to 4 were prepared in the same manner as in Example 1.
[153]
(2) Ammoxidation process of propylene
[154]
In addition, after performing the ammoxidation process of propylene by using each of the catalysts of Examples 2 to 4 instead of the catalyst of Example 1, the product was recovered and analyzed in the same manner as in Example 1.
[155]
Comparative Example 1
[156]
(1) Catalyst manufacturing process (using spray drying after co-precipitation)
[157]
First, 200 g of a Mo precursor (Ammonium Molybdate) was dissolved in 200 g of water at 85 °C, 270 g of silica sol was added thereto, stirred, and then heated to about 50 °C to prepare a solution A.
[158]
Independently of this, Bi precursor (Bi(NO 3 ) 3 ·5H 2 O) 69.4 g, Co precursor (Co(NO 3 ) 2 ·6H 2 O) 165 g, Fe precursor (Fe(NO 3 ) 2 ·9H 2 O) 115 g, Ni precursor (Ni(NO 3 ) 2 .6H 2 O) 10 g, K precursor (KNO 3 ) 10 g of nitric acid was added to a mixture of 17.5 g and heated to 50 ° C to prepare a solution B .
[159]
The solutions A and B were mixed with stirring to obtain an aqueous slurry, and the mixed aqueous slurry of the solutions A and B was dried at 150°C using a rotary nozzle type spray dryer. The dried product of the solid phase thus obtained was calcined at 580° C. for 3 hours to finally obtain the catalyst of Comparative Example 1.
[160]
(2) Ammoxidation process of propylene
[161]
The catalyst of Comparative Example 1 was used instead of the catalyst of Example 1, and the ammoxidation process of propylene was performed in the same manner as in Example 1.
[162]
After completion of the ammoxidation reaction of Comparative Example 1, the product was recovered and analyzed in the same manner as in Example 1.
[163]
Comparative Example 2
[164]
(1) Catalyst manufacturing process (using impregnation method)
[165]
A catalyst of Comparative Example 2 was prepared in the same manner as in Example 1, except that a precursor solution was prepared according to the composition shown in Table 1, and the silica carrier shown in Table 2 was used.
[166]
(2) Ammoxidation process of propylene
[167]
In addition, after performing the ammoxidation process of propylene by using the catalyst of Comparative Example 2 instead of the catalyst of Example 1, the product was recovered, and analysis was performed in the same manner as in Example 1.
[168]
[Table 1]
[169]
In Table 1, Mo is (NH 4 ) 6 Mo 7 O 24 , Bi is Bi(NO 3 ) 3 ·5H 2 O, Co is Co(NO 3 ) 2 ·6H 2 O, and Fe is Fe ( NO 3 ) 2 ·9H 2 O, Ni is Ni(NO 3 ) 2 ·6H 2 O, and K is KNO 3 . In addition, the omitted unit is g.
[170]
Meanwhile, the raw material input amount of Table 1 is calculated in consideration of the target composition of Table 2, that is, the stoichiometric molar ratio of the final metal oxide and the content of the metal oxide. If you want to directly measure the metal oxide composition and content of Table 2 below, it can be measured using measuring equipment such as ICP (Inductively Coupled Plasma, Inductively Coupled Plasma).
[171]
[Table 2]
[172]
Experimental Example 1: Catalyst Analysis
[173]
Each catalyst of Example 1 and Comparative Example 1 was analyzed according to the following analysis method:
[174]
XRD main peak intensity ratio : For each catalyst of Example 1 and Comparative Example 1, after diffraction analysis (X-Ray Diffraction, XRD) using Cu Kα X-rays, the analysis results are shown in FIG. 3 (Example 1), and FIG. 4 (Comparative Example 1) respectively.
[175]
3 (Example 1) and 4 (Comparative Example 1) in common, the main peaks (main peaks) appear at 26.3 ± 0.5 ° and 28.3 ± 0.5 °. Let A be the peak intensity appearing at 26.3 ± 0.5 °, and let B be the peak intensity appearing at 28.3 ± 0.5 °. .
[176]
BET specific surface area : For each catalyst of Example 1 and Comparative Example 1, using a BET specific surface area measuring instrument (manufacturer: BEL Japan, instrument name: BELSORP-mino X), nitrogen gas under liquid nitrogen temperature (77 K) The specific surface area was evaluated from the adsorption amount, and the evaluation results are shown in Table 1.
[177]
Pore ​​volume : Using an apparatus according to ASTM D4641 (manufacturer: BEL Japan, device name: BELSORP-mino X), the pore volume in each catalyst of Example 1 and Comparative Example 1 was measured, and the measurement results are shown in Table 1. .
[178]
Catalyst structure : It can be confirmed through an electron microscope such as a scanning electron microscope (SEM).
[179]
[Table 3]
[180]
1) Examples 1 to 4 and Comparative Examples 1 to 4 and Comparative Example 1 In Comparative Examples 1 to 4 and Comparative Example 1, the XRD peak intensity characteristics, pore volume and BET specific surface area characteristics may be related to the method for preparing the catalyst.
[181]
Specifically, in the catalyst of Comparative Example 1, a relatively large number of crystalline phases were formed through co-precipitation and spray drying processes, and thus had high crystallinity.
[182]
In addition, the catalyst of Comparative Example 1 has a secondary particle structure that contains almost no pores through co-precipitation and spray drying processes, and an effective surface area capable of participating in the reaction is limited by the external surface area.
[183]
On the other hand, the catalysts of Examples 1 to 4 were prepared by the impregnation method, and the amorphous phase was formed in a relatively large amount, and thus had low crystallinity.
[184]
In addition, the catalysts of Examples 1 to 4 have a structure including a large number of large pores while being prepared by the impregnation method, and an effective surface area capable of participating in the reaction is expanded to the pores.
[185]
In fact, upon X-ray diffraction (XRD) analysis of the catalysts of Examples 1 to 4 and Comparative Example 1 , a first peak having an intensity of B within a range of 2θ of 26.3±0.5 ° appears by the CoMoO 4 phase, and MoO A second peak with intensity B appeared within the range of 2θ of 28.3±0.5° by three phases.
[186]
The CoMoO 4 phase is the active phase for propylene ammoxidation, and the MoO 3 phase is the inactive phase. Accordingly, it can be seen that the higher the XRD peak intensity ratio (A/B), the lower the crystallinity of the catalyst and the lower the activity.
[187]
In this context, the catalyst of Comparative Example 1 has an XRD peak intensity ratio (A/B) of only 1.47, which is evaluated to have high crystallinity and low activity. On the other hand, the catalysts of Examples 1 to 4 satisfy the high range of the XRD peak intensity ratio (A/B), and are evaluated to have low crystallinity and high activity.
[188]
In addition, compared to Comparative Example 1, it was confirmed that the pore volume included in the catalysts of Examples 1 to 4 was large and had a larger BET specific surface area.
[189]
2) Comparison of Examples 1 to 4 and Comparative Example 2
[190]
Meanwhile, in Examples 1 to 4 and Comparative Example 1, the XRD peak intensity characteristics, pore volume and BET specific surface area characteristics may be related to the metal oxide composition in the catalyst.
[191]
Specifically, although the catalyst of Comparative Example 2 was prepared by the impregnation method, under the influence of a metal oxide containing only Mo and Bi, only a peak due to the inactive phase, MoO 3 , was formed, and a peak due to the active phase was not formed.
[192]
On the other hand, the catalysts of Examples 1 to 4, prepared by the impregnation method, under the influence of metal oxides comprising Mo and Bi as well as a number of suitable metal components, compared to the peak by the inactive phase MoO 3 , the active phase (In particular, the peak area by CoMoO 4 ) was formed more extensively.
[193]
In addition, it is evaluated that the catalysts of Examples 1 to 4 have an appropriate pore volume and a BET specific surface area by uniformly coating the pore walls of the silica carrier by CoMoO 4 as the active phase and the crystalline phase.
[194]
Experimental Example 2: Analysis of ammoxidation products
[195]
Each ammoxidation product of Examples 1 to 4 and Comparative Examples 1 and 2 was analyzed using chromatography (Gas chromatography, manufacturer: Agilent, device name: GC6890N) equipped with FID (Flame Ionization Detector) and TCD (Thermal conductivity detector). analyzed.
[196]
Specifically, products such as ethylene (ehthlene), hydrogen cyanide, acetaldehyde, acetonitrile, and acetonitrile (Acrylonitrile) were analyzed by FID, and NH 3 , O 2 , By analyzing gas products such as CO and CO 2 , the number of moles of propylene reacted in Example 1 and Comparative Example 1 and the number of moles of ammoxidation products were obtained.
[197]
By substituting the number of moles of propylene supplied along with the analysis result according to the following 1, 2, and 3, the conversion rate of propylene, the selectivity and yield of acrylonitrile, which is an ammoxidation product of propylene, are calculated, and the calculated values ​​are Table 2 shows.
[198]
[Equation 1]
[199]

[200]
[Equation 2]
[201]

[202]
[Equation 3]
[203]

[204]
[Table 4]
[205]
As a result of preparing the catalyst of Comparative Example 1 through co-precipitation and spray drying, the effective surface area (BET specific surface area) that can participate in the reaction is limited to the outer surface portion, and the formation of the active phase and amorphous CoMoO 4 is suppressed.
[206]
Accordingly, the catalyst of Comparative Example 1 has low activity due to a narrow effective surface area and low active phase content, and may be easily broken or broken due to high crystallinity. In particular, when the catalyst is broken or broken by high temperature during the ammoxidation reaction of propylene, Mo or the like is eluted from the inside of the catalyst to the surface, and catalyst performance may be deteriorated.
[207]
In fact, during the reaction using the catalyst of Comparative Example 1, it is confirmed that the conversion rate of propylene is 56.5%, and the yield of acrylonitrile is only 33.7%.
[208]
On the other hand, although the catalyst of Comparative Example 2 was prepared by the impregnation method, effective active phases, particularly active phases (CoMoO 4 ) that can participate in the reaction, were formed under the influence of a metal oxide containing only Mo and Bi as metal components. can't be
[209]
In fact, it is confirmed that during the reaction using the catalyst of Comparative Example 2, the conversion rate of propylene and the yield of acrylonitrile are lower than those of Comparative Example 1.
[210]
On the other hand, the catalysts of Examples 1 to 4, as a result of being prepared by the impregnation method, have a large effective surface area (BET specific surface area) that can participate in the reaction, and the formation of the active phase CoMoO 4 is increased.
[211]
Accordingly, the catalysts of Examples 1 to 4 have high activity due to their large effective surface area and high active phase content, and may not break or break even at high temperatures applied during the ammoxidation reaction of propylene.
[212]
In fact, during the reaction using the catalysts of Examples 1 to 4, the conversion rate of propylene was 70% or more, and the yield of acrylonitrile was high as 60% or more.
[213]
Overall, a catalyst having an XRD main peak intensity ratio (A/B) of 1.5 or more while the metal oxide composition satisfies the aforementioned formula (1) can significantly improve the conversion rate of propylene and the yield of acrylonitrile during the ammoxidation reaction of propylene. is evaluated as having
Claims
[Claim 1]
A metal oxide represented by the following formula (1) containing; and upon X-ray diffraction analysis by Cu Cα, a first peak having an intensity of A appears within a range where 2θ is 26.3±0.5°, and 2θ is 28.3±0.5° A second peak having an intensity of B appears within, and an intensity ratio (A/B) of the first peak to the second peak is 1.5 or more, the catalyst for ammoxidation of propylene: [Formula 1 ] A and B are different and each independently is one or more elements of Ni, Mn, Co, Zn, Mg, Ca, and Ba, C is one or more elements of Li, Na, K, Rb, and Cs, and D is Cr, W, B, Al, Ca, and at least one element of V, wherein a to f, x, and y are the mole fractions of atoms or groups of atoms, a is 0.1 to 7, b is 0.1 to 7, provided that the sum of a and b is 0.1 to 7, c is 0.1 to 10, d is 0.01 to 5, e is 0.1 to 10, f is 0 to 10, x is 11 to 14, y is the Mo , Bi, Fe, A, B, C, and D are values ​​that can be determined by the respective oxidation numbers.
[Claim 2]
The catalyst for ammoxidation of propylene according to claim 1, wherein the catalyst has an intensity ratio (A/B) of the first peak to the second peak of 3.0 or more during X-ray diffraction analysis by Cu Cα.
[Claim 3]
The catalyst for ammoxidation of propylene according to claim 1, wherein the catalyst has a BET specific surface area of ​​50 to 300 m 2 /g.
[Claim 4]
The catalyst for ammoxidation of propylene according to claim 1, wherein the pore volume in the catalyst is 0.3 to 1.3 cm 3 /g.
[Claim 5]
The catalyst for ammoxidation of propylene according to claim 1, wherein the metal oxide is represented by the following Chemical Formula 1-1: [Formula 1-1] In Chemical Formula 1-1, x, a to e, and y The definition is the same as in Paragraph 1.
[Claim 6]
The catalyst for ammoxidation of propylene according to claim 1, wherein the catalyst further comprises a silica carrier supporting the metal oxide.
[Claim 7]
The catalyst for ammoxidation of propylene according to claim 6, wherein the weight ratio of the metal oxide and the silica carrier is 15:85 to 35:65.
[Claim 8]
Preparing a first precursor solution containing a Mo precursor, Fe precursor; and preparing a second precursor solution including at least one of Ni, Mn, Co, Zn, Mg, Ca, and Ba; a Bi precursor; a precursor of at least one of Ni, Mn, Co, Zn, Mg, Ca, and Ba different from the second precursor solution; and preparing a third precursor solution including a precursor of one or more elements of Li, Na, K, Rb, and Cs, so that the molar ratio of the metal satisfies the stoichiometric molar ratio of Formula 1 below, Mixing a third precursor solution, supporting the silica carrier in the mixture of the first to third precursor solutions, drying the silica carrier on which the mixture of the first to third precursor solutions is supported, and the A method for preparing a catalyst for ammoxidation of propylene, comprising the step of calcining the dried material: [Formula 1] In Formula 1, A and B are different and each independently represent at least one element of Ni, Mn, Co, Zn, Mg, Ca, and Ba, and C is at least one of Li, Na, K, Rb, and Cs. element, D is one or more of Cr, W, B, Al, Ca, and V, wherein a to f, x, and y are mole fractions of atoms or groups of atoms, a is 0.1 to 7, and b is 0.1 to 7, with the proviso that the sum of a and b is 0.1 to 7, c is 0.1 to 10, d is 0.01 to 5, e is 0.1 to 10, f is 0 to 10, and x is 11 to 14 , y is a value that can be determined by the respective oxidation numbers of Mo, Bi, Fe, A, B, C, and D.
[Claim 9]
The method of claim 8, wherein in the step of preparing the first precursor solution, citric acid, oxalic acid, or a mixture thereof is added as an additive.
[Claim 10]
The method of claim 8, wherein the preparing of the first precursor solution is performed at 50 to 90°C.
[Claim 11]
The method of claim 8, wherein the preparing of the second precursor solution is a step of preparing an aqueous solution containing water, a Fe precursor, and a Co precursor.
[Claim 12]
The method of claim 8, wherein the preparing of the third precursor solution is a step of preparing a solution containing nitric acid, a Bi precursor, a Ni precursor, and a K precursor.
[Claim 13]
The method of claim 8, wherein the preparing of the second precursor solution and the preparing of the second precursor solution are each independently performed at 20 to 50° C., the method for preparing a catalyst for ammoxidation of propylene .
[Claim 14]
The method according to claim 8, wherein the mixing of the first to third precursor solutions comprises mixing the second and third precursor solutions, and mixing the mixture of the second and third precursor solutions with the first precursor solution. A method for producing a catalyst for the ammoxidation of propylene, comprising the step of dropping to the.
[Claim 15]
According to claim 8, wherein the step of supporting the mixture of the first to third precursor solutions on the silica carrier, the silica carrier and the first to third precursor solutions within a temperature range of 20 to 30 ℃ the primary A method for producing a catalyst for ammoxidation of propylene, comprising the step of mixing, and a second mixing step of the first mixture within a temperature range of 70 to 90 ℃.
[Claim 16]
The method of claim 8, wherein the first and second mixing are each independently performed for 1 to 3 hours.
[Claim 17]
The method according to claim 8, wherein the drying of the silica carrier on which the mixture of the first to third precursor solutions is supported is performed within a temperature range of 100 to 120 °C, the method for producing a catalyst for ammoxidation of propylene .
[Claim 18]
The method of claim 8, wherein the drying of the silica carrier on which the mixture of the first to third precursor solutions is supported is performed for 5 to 12 hours.
[Claim 19]
The method of claim 8, wherein the calcining of the dried material is performed within a temperature range of 500 to 700 °C.
[Claim 20]
A process for the ammoxidation of propylene comprising reacting propylene and ammonia in a reactor in the presence of the catalyst of claim 1 .