Title of Invention: Catalyst for ammoxidation of propylene, method for producing same, 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. 10-2020-0087104 dated July 14, 2020, and all contents disclosed in the literature of the Korean patent application are incorporated as a part of this specification.
[3]
The present invention relates to a catalyst for ammoxidation of propylene, a method for producing the same, and a method for ammoxidation of propylene using the same.
[4]
background
[5]
Acrylonitrile can be prepared through the ammoxidation of propylene.
[6]
Specifically, the ammoxidation reaction of propylene includes a reduction reaction of ammonia and propylene and a reoxidation reaction by oxygen, and a fluidized bed reactor is generally used to control heat generated during these reactions.
[7]
As a catalyst for ammoxidation of propylene, since Mo (molybdenum)-Bi (bismuth) oxide catalysts have been proposed, catalysts to which metals having various oxidation states are added have been proposed. However, despite the diversification of the catalyst composition, research on the structure and physical properties thereof is insufficient, and there is a limit in increasing the yield of acrylonitrile.
[8]
Specifically, the sol-gel method is widely known as a method for preparing a catalyst for ammoxidation of propylene, which corresponds to a method in which a metal precursor solution and silica sol are co-precipitated, and the co-precipitation product is spray-dried and then calcined.
[9]
According to this sol-gel method, a catalyst having a secondary particle structure in which metal oxide particles and silica particles are aggregated is prepared. The binding force of the particles constituting the secondary particles is weak, so that they are worn out in the fluid reactor or split into primary particles to catalytic activity easy to lose Therefore, when using the catalyst prepared by the sol-gel method, it is necessary to continuously add the catalyst (make-up) during the ammoxidation reaction of propylene, and even if it is added, there is a limit in increasing the yield of acrylonitrile.
[10]
Moreover, the catalyst prepared by the sol-gel method may already contain a large amount of fine powder before being introduced into the flowable reactor. In the process of spray-drying the co-precipitation product of the metal precursor solution and the silica sol, it may not be aggregated to an appropriate size and fine powder may be generated. Accordingly, the catalyst prepared by the sol-gel method has a problem in that its productivity is low and manufacturing cost is high.
[11]
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[12]
An object of the present invention is to provide a catalyst for ammoxidation of propylene having a low fine content and excellent durability, and to prepare acrylonitrile in a higher yield by using the catalyst.
[13]
means of solving the problem
[14]
Specifically, in one embodiment of the present invention, a catalyst having a structure in which a metal oxide of a specific composition is supported is provided on a silica carrier in which the pore diameter and the apparent density are each controlled to a specific range.
[15]
Effects of the Invention
[16]
The catalyst of one embodiment may be prepared by an impregnation method, and may have less fine powder content and superior durability compared to a catalyst prepared by a sol-gel method.
[17]
In addition, depending on the composition of the metal oxide, the pore diameter and apparent density of the silica carrier, the durability may be improved while exhibiting a more uniform particle size distribution.
[18]
Therefore, when using the catalyst of one embodiment, acrylonitrile can be mass-produced in high yield without additional supply of catalyst during the ammoxidation process of propylene in the fluidized bed reactor.
[19]
Brief description of the drawing
[20]
1 schematically shows a catalyst having a secondary particle structure prepared using a co-precipitation method.
[21]
2 schematically shows a catalyst according to the embodiment.
[22]
Modes for carrying out the invention
[23]
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 it should be understood that all modifications, equivalents and substitutes included in the spirit and scope of the present invention are included. 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.
[24]
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, a second component may also be referred to as a first component.
[25]
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 should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.
[26]
Hereinafter, “particle diameter Dv” means a particle diameter at the v% point of the cumulative volume distribution according to the particle diameter. That is, D50 is the particle size at the 50% point of the cumulative volume distribution according to the particle size, D90 is the particle size at the 90% point of the cumulative volume distribution according to the particle size, and D10 is the particle size at the 10% point of the cumulative volume distribution according to the particle size. is the size
[27]
[28]
Hereinafter, the catalyst for ammoxidation of propylene of one embodiment will be described in detail with reference to the drawings.
[29]
[30]
Catalyst for ammoxidation of propylene
[31]
[32]
In one embodiment of the present invention, a silica carrier comprising pores having a diameter of 2 to 15 nm and an apparent density of 0.25 to 1.0 g/cc; and a metal oxide supported on the silica carrier and including molybdenum (Mo), bismuth (Bi), and a heterogeneous metal; provides a catalyst for ammoxidation of propylene, including.
[33]
[34]
A commonly known catalyst for ammoxidation of propylene is prepared by a sol-gel method and provided in a secondary particle structure in which metal oxide nanoparticles and silica nanoparticles are aggregated ( FIG. 1 ).
[35]
This is a structure in which the metal oxide particles are evenly distributed inside and outside, but almost no internal pores, and the site that can participate in the ammoxidation reaction of propylene is limited to the outer surface portion.
[36]
[37]
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 ).
[38]
For example, the silica carrier may be immersed in a metal precursor aqueous solution prepared to satisfy a desired stoichiometric molar ratio of the metal oxide, and the metal precursor aqueous solution may be impregnated in the silica carrier.
[39]
Thereafter, when the solvent (ie, water) is removed through a 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. .
[40]
The catalyst of one embodiment prepared as described above may have a narrower particle size distribution than a catalyst prepared with the same composition by the sol-gel method, and may have a smaller content of fine powder, even if a classification process is not performed as a post-processing after preparation.
[41]
[42]
In particular, as the catalyst of one embodiment includes a silica carrier having a pore diameter and an apparent density within an appropriate range of 2 to 15 nm and 0.25 to 1.0 g/cc, respectively, it is possible to further reduce the fine powder content and improve durability. have.
[43]
In addition, the catalyst of one embodiment is Mo and Bi, which are known to increase the activity of the ammoxidation reaction, as well as a metal that forms an active site at a suitable level for the ammoxidation reaction of propylene. Through a metal oxide, the catalyst activity can be further increased.
[44]
Therefore, when using the catalyst of one embodiment, acrylonitrile can be obtained in high yield without additional supply of a catalyst during the ammoxidation process of propylene in a fluidized bed reactor.
[45]
[46]
Hereinafter, the catalyst of one embodiment will be described in more detail,
[47]
[48]
Pore ​​Diameter of Silica Carrier
[49]
[50]
The pore diameter of the silica carrier means the average size of pores in the particles, and in the curve of dVp / dDp according to Dp obtained by the BJH calculation formula in the desorption isothermal curve of nitrogen gas under liquid nitrogen temperature, at the maximum point of dVp / dDp Dp value of In the above, Dp means the pore diameter of the particle, and Vp means the pore volume of the particle.
[51]
[52]
When the pore diameter of the silica carrier is too small to be less than 2 nm, the impregnation of the metal oxide into the pores of the silica carrier is not uniformly made, so that the activity of the final catalyst is lowered, and the metal oxide not impregnated in this way is dissociated fines can be formed.
[53]
On the other hand, when the pore diameter of the silica carrier is excessively large to more than 15 nm, the final catalytic activity is high, but as the pore diameter is large, the apparent density and durability are lowered, and thus the silica carrier is easily abraded and pulverized in the fluidized bed reactor.
[54]
Therefore, even when a silica carrier having an excessively small pore diameter of less than 2 nm as well as a silica carrier exceeding 15 nm is used, a catalyst must be continuously added (make-up) in the mass production process of acrylonitrile, and additional Even so, there is a limit to increasing the yield of acrylonitrile.
[55]
Accordingly, in one embodiment of the present invention, the pore diameter of the silica carrier is limited within the range of 2 to 15 nm.
[56]
[57]
The pore diameter of the silica carrier may be controlled within the range of 2 to 30 nm, depending on desired physical properties for the final catalyst.
[58]
Specifically, when the composition and loading amount of the metal oxide are the same, as the pore diameter of the silica carrier supporting it decreases within the range of 2 to 15 nm, the fine amount of the final catalyst decreases and the particle size distribution becomes uniform. have.
[59]
For example, the pore diameter of the silica carrier may be controlled within a range of 15 nm or less, 14 nm or less, 13 nm or less, or 12 nm or less while being 2 nm or more.
[60]
[61]
Apparent Density of Silica Carrier
[62]
[63]
In general, the apparent density refers to a value obtained by measuring the weight (W1) of a porous body contained in a container having a top shell of 3 cc and dividing it by 3 cc of a top shell of the container.
[64]
[65]
When the D50 particle diameter of the silica carrier is the same, as the pore diameter increases, the apparent density tends to decrease.
[66]
When the pore diameter of the silica carrier becomes large and the apparent density becomes too small to less than 0.25 g/cc, the final catalytic activity is high, but the apparent density and durability are low, and thus the silica carrier is easily abraded and pulverized in the fluidized bed reactor.
[67]
On the other hand, if the pore diameter of the silica carrier is small and the apparent density is excessively increased to more than 1.0 g/cc, the impregnation of the metal oxide into the pores of the silica carrier is not uniformly made, and thus the activity of the final catalyst is low. The non-impregnated metal oxide may dissociate to form fine powder.
[68]
Therefore, in the mass production process of acrylonitrile, the catalyst is continuously added in the mass production process of acrylonitrile even when not only a silica carrier with an apparent density of less than 0.25 g/cc but also a silica carrier that is too large over 1.0 g/cc is used. There is a limit in increasing the yield of acrylonitrile even if it is added.
[69]
[70]
The apparent density of the silica carrier may be controlled within the range of 0.25 to 1.0 g/cc, depending on desired physical properties for the final catalyst.
[71]
Specifically, when the composition and loading amount of the metal oxide are the same, as the apparent density of the silica support supporting it increases within the range of 0.25 to 1.0 g/cc, the fine amount of the final catalyst can be reduced.
[72]
For example, the apparent density of the silica carrier may be 0.25 g/cc or more, 0.27 g/cc or more, 0.29 g/cc or more, or 0.3 g/cc or more, and 1.0 g/cc or less.
[73]
[74]
D50 particle size of silica carrier
[75]
[76]
The D50 particle diameter of the silica carrier may be in the range of 50 to 150 μm.
[77]
Specifically, the silica carrier has a lower limit of 50 μm or more, 51 μm or more, 53 μm or more, or 55 μm or more of the D50 particle size, and an upper limit of 150 μm or less, 110 μm or less, 90 μm or less, or 75 μm or less. can do.
[78]
[79]
Ammonia Desorption Amount of Silica Carrier
[80]
[81]
In the initial stage of the catalytic reaction, a process in which reactants are chemically adsorbed on the catalyst surface is required, and the active site and surface area of ​​the catalyst are directly related to the adsorption capacity and the resulting chemical reaction.
[82]
Also, chemisorption on the catalyst surface tends to increase with increasing temperature, although the rate of adsorption is slower than that of physisorption.
[83]
[84]
In this regard , the ammonia temperature elevated desorption method (NH 3 -TPD) , which measures the degree of the acid site strength of the catalyst by the desorption degree (TPD: Temperature Programmed Desorption) of ammonia (NH 3 ) is widely known.
[85]
For example, after pretreatment at 400° C. for about 1 hour, NH 3 is adsorbed at about 100° C. with 5% NH 3 / He (50 cc/min) for 1 hour , and physical adsorption while flowing He at the same temperature After removing the formed NH 3 , the temperature of the desorbed NH 3 can be measured while raising the temperature to 800 °C.
[86]
[87]
The silica carrier has an ammonia (NH 3 ) desorption amount measured by the ammonia temperature elevation desorption method (NH 3 -TPD) of 1.3 mmol/g or less, 1.2 mmol/g or less, 1.1 mmol/g or less, or 1.00 mmol/g or less (provided that more than 0 mmol/g), the adsorption capacity may be excellent.
[88]
This may be a factor in reducing the amount of ammonia desorbed from the silica carrier and the catalyst including the same during the ammoxidation reaction of propylene, and improving the conversion rate of propylene, selectivity of acrylonitrile, and yield.
[89]
[90]
Composition of metal oxides
[91]
[92]
On the other hand, even if it has the same structure as the catalyst of the embodiment, depending on the type and content of the components constituting the metal oxide, a small number of active sites or rather an excessively high density of active sites may be formed.
[93]
In this regard, it is necessary to form an appropriate active site by adding a dissimilar metal, rather than a metal oxide containing only Mo and Bi as active metals.
[94]
[95]
Specifically, in the catalyst of the embodiment, the type and content of the metal constituting the metal oxide may satisfy Chemical Formula 1 above.
[96]
[Formula 1]
[97]
Mo 12 Bi a Fe b A c B d C e O x
[98]
In Formula 1,
[99]
A is one or more of Ni, Mn, Co, Zn, Mg, Ca, and Ba,
[100]
B is one or more of Li, Na, K, Rb, and Cs,
[101]
C is one or more of Cr, W, B, Al, Ca, and V,
[102]
wherein a to e and x are each a fraction of an atom or group, a is 0.1 to 5, b is 0.1 to 5, c is 0.01 to 10, d is 0.01 to 2, and e is 0 to 10; , x is 24-48.
[103]
[104]
In particular, when the metal oxide is represented by the following Chemical Formula 1-1, the effect of increasing the conversion rate by increasing the movement rate of lattice oxygen of molybdenum of Fe, and the formation of a complex oxide of Co with molybdenum to increase the partial oxidation reaction characteristics of propylene With the synergistic effect of the effect and the effect of increasing the AN selectivity by dispersing the active sites of the complex oxide containing molybdenum of K, the activity in the ammoxidation reaction of propylene can be higher:
[105]
[Formula 1-1]
[106]
Mo 12 Bi a Fe b Co c K d O x
[107]
In Formula 1-1, a to d and x are each an atom or fraction of an atomic group, a is 0.1 to 5, specifically 0.1 to 2.0, b is 0.1 to 5, specifically 0.5 to 3.0, , c is 0.01 to 10, specifically 1 to 10, d is 0.01 to 2, specifically 0.01 to 1.0, and x may be 24 to 48, specifically 28 to 45.
[108]
[109]
Metal oxide: weight ratio of carrier
[110]
[111]
The catalyst of one embodiment may include the metal oxide and the silica carrier in a weight ratio of 15:85 to 35:65, specifically 20:80 to 35:65 (metal oxide:silica carrier).
[112]
Within this range, the catalyst of one embodiment may have high selectivity of acrylonitrile with high activity.
[113]
[114]
Catalyst structure
[115]
[116]
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 positioned inside the second pore and occupying an empty space excluding the inner coating layer.
[117]
Here, the diameter of the second pores may be 2 to 15 nm, and the first pores may be determined according to the amount of the metal oxide supported in the second pores.
[118]
[119]
In view of such a supported structure, as compared to a catalyst prepared by a sol-gel method, it may be a catalyst having a small content of fine powder, excellent durability, and high activity.
[120]
Therefore, when using the catalyst of one embodiment, acrylonitrile can be obtained in high yield without additional supply of catalyst during the ammoxidation process of propylene in the fluidized bed reactor.
[121]
[122]
Specifically, the catalyst of one embodiment may have an egg-shell structure.
[123]
To this end, the silica carrier includes a non-porous core portion; and a porous shell portion located on the surface of the non-porous core and including second pores having a diameter of 2 to 30 nm.
[124]
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. it could be
[125]
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.
[126]
[127]
D50 particle size of final catalyst and uniformity of particle size distribution
[128]
[129]
In the catalyst of one embodiment, in a state in which the metal oxide is supported on the silica carrier, the particle size distribution relative to D50 may be uniform and the fine powder content may be small.
[130]
Specifically, the catalyst of the embodiment may have a D50 particle diameter of 30 to 200 μm, and a ratio of [difference between D90 particle diameter and D10 particle diameter] to this D50 particle diameter is 2.0 or less, indicating a narrow particle size distribution.
[131]
More specifically, in the catalyst of one embodiment, the lower limit of the D50 particle size is 30 µm or more, 35 µm or more, 40 µm or more, or 45 µm or more, and the upper limit is 200 µm or less, 190 µm or less, 180 µm or less, 170 It can be set to micrometer or less, 160 micrometers or less, or 150 micrometers or less.
[132]
In addition, the catalyst of one embodiment has a ratio of [difference between D90 particle diameter and D10 particle diameter] to D50 particle diameter of less than 2.0, 1.7 or less, 1.5 or less, 1.3 or less, or 1.0 or less, thereby exhibiting a narrow particle size distribution. .
[133]
In other words, the uniformity of the particle size distribution exhibited by the catalyst of the one embodiment can be supported by the fact that the D10 particle diameter and the D90 particle diameter relative to the D50 particle diameter satisfy the relationship of Equation 1, specifically, Equation 1-1 below:
[134]
[Equation 1]
[135]
(D90-D10)/D50 ≤ 2.0
[136]
[Equation 1-1]
[137]
(D90-D10)/D50 ≤1.0
[138]
[139]
Catalyst wear loss
[140]
[141]
Particle abrasion refers to a phenomenon in which solid particles are decomposed through mechanical and chemical processes. Particle wear is classified into two forms: abrasion and fragmentation, and both forms can occur together.
[142]
In particular, in the fluidized bed process, the catalyst particles may be abraded and micronized, and it is necessary to continuously make-up the catalyst by the worn amount, which may affect the economic feasibility of the entire process.
[143]
[144]
ASTM9797-00 method is known as a standard for measuring wear of particles. This is, after filling a vertical inner tube with an inner diameter of 35 mm and a height of 710 mm with 50 g of catalyst (W0), flowing N 2 gas at 10 L/min, and then measuring the amount (W) of the catalyst collected in the fine filter after 5 hours Therefore, it corresponds to a method of measuring abrasion resistance (abrasion loss, Attrition loss) using the following equation.
[145]
Wear resistance (attrition loss) (%) = (W0)/WX 100
[146]
[147]
The catalyst of one embodiment has abrasion resistance (attrition loss) measured according to the ASTM9797-00 method of 10% or less, 9% or less, 8% or less, 7% or less, 6% or less, or 5% or less. , the amount of loss is very small, and the abrasion resistance may be excellent.
[148]
Therefore, the catalyst of one embodiment exhibits superior wear resistance compared to the catalyst prepared by the sol-gel method, and acrylonitrile can be prepared in a higher yield without additional supply of a catalyst during the ammoxidation reaction of propylene in a fluidized bed reactor. .
[149]
[150]
Method for preparing a catalyst for ammoxidation of propylene
[151]
[152]
In another embodiment of the present invention, there is provided a method for preparing the catalyst of the above-described embodiment using an impregnation method.
[153]
As briefly described above, the catalyst of one embodiment may be prepared through a series of processes of supporting an aqueous metal precursor solution on the silica carrier using an impregnation method, drying and calcining.
[154]
[155]
More specifically, as a method for preparing the catalyst of one embodiment,
[156]
preparing a first aqueous precursor solution including a Mo precursor;
[157]
preparing a second aqueous precursor solution including a Bi precursor and a dissimilar metal precursor;
[158]
Supporting a mixture of the first and second aqueous precursor solutions on a silica carrier, including pores having a diameter of 2 to 15 nm and having an apparent density of 0.25 to 1.0 g/cc;
[159]
drying the silica carrier on which the mixture of the first and second aqueous precursor solutions is supported, and
[160]
and calcining the dried material.
[161]
[162]
Hereinafter, a description overlapping with the above will be omitted, and the catalyst preparation process of the embodiment will be described in detail.
[163]
[164]
Process for preparing the first aqueous precursor solution
[165]
[166]
In the step of preparing the first aqueous precursor solution, an additive including citric acid, oxalic acid, or a mixture thereof may be added.
[167]
The additive functions as a strength control agent in a catalyst manufacturing process using co-precipitation and spray drying, but in one embodiment serves to make the first aqueous precursor solution transparent.
[168]
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.
[169]
[170]
Manufacturing process of the second aqueous precursor solution
[171]
[172]
Except for the Mo precursor included in the first aqueous precursor solution, a second aqueous precursor solution including the remaining metal precursor may be prepared.
[173]
Specifically, the preparing of the second aqueous precursor solution includes a Bi precursor, an Fe precursor, an A precursor (A = at least one element among Ni, Mn, Co, Zn, Mg, Ca, and Ba), and a B precursor (B = Li, Na, K, Rb, and one or more elements of Cs) may be a step of preparing an aqueous solution of the second precursor.
[174]
More specifically, in the step of preparing the second aqueous precursor solution, the type of the metal precursor other than the Mo precursor may be selected in consideration of the final desired metal oxide composition in the catalyst.
[175]
For example, in consideration of the metal oxide composition satisfying Chemical Formula 1-1, a second aqueous precursor solution including a Bi precursor, an Fe precursor, a Co precursor, and a K precursor may be prepared.
[176]
Here, it is also possible to prepare a second precursor aqueous solution further comprising a C precursor (one or more elements of Cr, W, B, Al, Ca, and V).
[177]
[178]
mixture of first and second aqueous precursor solutions
[179]
[180]
Processes for preparing the first and second aqueous precursor solutions are independent of each other, and the production order is not limited.
[181]
However, the mixture of the first and second aqueous precursor solutions may be prepared so that the molar ratio of the metal satisfies the stoichiometric molar ratio of Formula 1 below:
[182]
[Formula 1]
[183]
Mo 12 Bi a Fe b A c B d C e O x
[184]
In Formula 1,
[185]
A is one or more of Ni, Mn, Co, Zn, Mg, Ca, and Ba,
[186]
B is one or more of Li, Na, K, Rb, and Cs,
[187]
C is one or more of Cr, W, B, Al, Ca, and V,
[188]
Wherein a to e, and x is a fraction of an atom or atomic group, a is 0.1 to 5, b is 0.1 to 5, c is 0.01 to 10, d is 0.01 to 2, e is 0 to 10, x is 24-48.
[189]
[190]
Supporting process of the first and second aqueous precursor solution mixture in a carrier
[191]
[192]
After mixing the first and second aqueous precursor solutions, it may be supported on a silica carrier.
[193]
Here, the silica carrier including the aforementioned second pores may be added to the mixture of the first and second aqueous precursor solutions so that the mixture of the first and second aqueous precursor solutions is supported on the pores of the silica carrier. .
[194]
Specifically, the D50 size of the silica carrier itself on which the metal oxide is not supported may be 20 to 400 μm.
[195]
[196]
Drying process of the carrier on which the mixture of the first and the second precursor aqueous solution is supported
[197]
[198]
The drying of the silica carrier on which the mixture of the first and second aqueous precursor solutions is supported may include first vacuum drying the silica carrier on which the mixture of the first and second aqueous precursor solutions is supported at 120 to 160 mbar, and Secondary vacuum drying of the first vacuum-dried material at 30 to 50 mbar may include obtaining a silica carrier on which a mixture of the first and second precursors is supported.
[199]
Specifically, the first vacuum drying is performed at 60 to 80 ° C. for 1 to 2 hours, and the second vacuum drying is performed at 80 to 100 ° C. for 15 to 45 minutes, whereby the solvent (ie, water) is removed and , only the first and second precursors may remain on the pore wall surface of the silica carrier.
[200]
Although the material on which the secondary vacuum drying has been completed can be directly fired, by tertiary drying at normal pressure, even the solvent (ie, water) remaining after the secondary vacuum drying can be effectively removed.
[201]
Specifically, the tertiary drying may be performed at 100 to 120° C. for 20 to 30 hours.
[202]
However, this is only an example, and the solvent (ie, water) is removed, and the first and second precursors are not particularly limited as long as they are dry conditions to obtain the supported carriers.
[203]
[204]
Final firing process
[205]
[206]
Finally, the dried material, that is, the carrier on which the first and second precursors are supported, is calcined within a temperature range of 500 to 700° C. for 2 to 5 hours to finally obtain a catalyst.
[207]
However, each of the drying and firing conditions is only an example, and it is sufficient if the solvent is sufficiently removed from the internal pores of the carrier and the conditions capable of oxidizing the metal precursor are sufficient.
[208]
[209]
Method for ammoxidation of propylene
[210]
[211]
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.
[212]
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.
[213]
[214]
For matters other than the catalyst of the embodiment, reference may be made to matters generally known in the art, and further detailed description thereof will be omitted.
[215]
[216]
Hereinafter, embodiments of the present invention will be described in more detail in the following examples. However, the following examples are merely illustrative of embodiments of the invention, and the content of the present invention is not limited by the following examples.
[217]
[218]
Example 1
[219]
[220]
(1) Preparation process of precursor solution
[221]
In distilled water, 10.59 g of Mo precursor ((NH 4 ) 6 Mo 7 O 24 ) and 5.3 g of citric acid were added and mixed to prepare a Mo precursor solution.
[222]
Independently, in distilled water, 1.82 g of Bi precursor (Bi(NO 3 ) 3 ·5H 2 O), 9.49 g of Co precursor (Co(NO 3 ) 2 ·6H 2 O), 2.99 g of Fe precursor (Fe (NO 3 ) 2 9H 2 O), and 0.35 g of a K precursor (KNO 3 ) were added, and 2.29 g of nitric acid (HNO 3 ) was added and mixed, followed by mixing of Bi, Fe, Co, and K precursors A solution was prepared.
[223]
the Mo precursor solution; and the Bi, Fe, Co, and K precursor mixed solution was mixed to complete a Mo, Bi, Fe, Co, and K precursor mixed solution.
[224]
In the precursor mixed solution, the total amount of distilled water is 45.74 g.
[225]
(2) Supporting process of precursor solution in silica carrier (using impregnation method)
[226]
Silica (SiO 2 , D60-120A(N), AGC Si-Tech Co., Ltd.) particles containing pores having an average diameter of 12 nm, an apparent density of 0.32 g/cc, and a D50 particle size of 70 μm are supported was used as
[227]
18.30 g of the silica carrier was added to the precursor mixture solution of Mo, Bi, Fe, Co, and K, and stirred at room temperature and 80 ° C. for 2 hours, respectively, in the pores of the silica carrier. Mo, Bi, The Fe, Ni, Co, and K precursor mixed solution was sufficiently supported.
[228]
(3) Drying and sintering process of the silica carrier on which the precursor solution is loaded
[229]
After that, the silica carrier on which the Bi, Fe, Co, and K precursor mixed solution is supported is recovered and put into a rotary vacuum dryer, and then vacuum dried for 1 hour and 40 minutes at a pressure of 140 mbar and a temperature of 70 ° C. and subsequently vacuum-dried for 30 minutes under a pressure of 40 mbar and a temperature of 90 °C.
[230]
The material completed up to the second vacuum drying is recovered, put into an oven, and dried for 24 hours under normal pressure and 110 ℃ temperature condition, and then 3 hours while maintaining the temperature of 580 ℃ in the box kiln in an air atmosphere. During heat treatment, the catalyst of Example 1 was finally obtained.
[231]
(4) Ammoxidation process of propylene
[232]
In a tubular reactor having an inner diameter of 3/8 inch (inch), 0.05 g of quartz wool was filled for activation of the catalyst, and 0.2 g of the catalyst of Example 1 was filled in the reactor.
[233]
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 10 °C/min, nitrogen and ammonia gas were flowed as a pretreatment process. Accordingly, after the internal temperature of the reactor reached 400° C., which is a temperature at which the ammoxidation reaction is possible, it was maintained in an atmosphere of reducing gas for 15 minutes so that sufficient pretreatment was performed.
[234]
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 feed amount of the reactant was configured to be propylene: ammonia: air = 0.8: 1.2: 8 by volume, and the total weight hourly space velocity (WHSV) of propylene, ammonia, and air was 1.54 h -1 .　
[235]
After completion of the ammoxidation reaction, the product was recovered and analyzed using various equipment to confirm whether acrylonitrile was well produced.
[236]
The analysis method, analysis result, and the like will be described in detail in the Experimental Examples to be described later.
[237]
[238]
Examples 2 to 7
[239]
[240]
A precursor solution was prepared according to the composition shown in Table 1, and the silica carrier shown in Table 2 was used, but the rest were the same as in Example 1 to prepare each catalyst of Examples 2 to 7.
[241]
In addition, the ammoxidation process of propylene was performed using each catalyst of Examples 2 to 7 instead of the catalyst of Example 1, and the product was recovered and analyzed in the same manner as in Example 1.
[242]
[243]
Comparative Example 1
[244]
[245]
(1) Catalyst manufacturing process (using spray drying after co-precipitation)
[246]
First, in distilled water, 10.59 g of Mo precursor ((NH 4 ) 6 Mo 7 O 24 ) and 5.3 g of citric acid were added and mixed to prepare a Mo precursor solution.
[247]
Independently, in distilled water, 1.82 g of Bi precursor (Fe(NO 3 ) 3 ·5H 2 O), 9.49 g of Co precursor (Co(NO 3 ) 2 ·6H 2 O), 2.99 g of Fe precursor (Fe (NO 3 ) 2 9H 2 O), and 0.35 g of K precursor (KNO 3 ) were added, and 1.13 g of nitric acid (HNO 3 ) was added and mixed, followed by mixing of Bi, Fe, Co, and K precursors A solution was prepared.
[248]
the Mo precursor solution; and the Bi, Fe, Co, and K precursor mixed solution, 22.53 g of silica sol (LUDOX AS 40, solid content: 40 %, Grace) was added thereto and stirred, followed by a disk-type spray dryer. and spray-dried at 120 °C (inlet) and 230 °C (outlet) conditions.
[249]
The powder thus obtained was calcined at 580° C. for 3 hours to finally obtain the catalyst of Comparative Example 1.
[250]
(3) Ammoxidation process of propylene
[251]
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.
[252]
After completion of the ammoxidation reaction of Comparative Example 1, the product was recovered and analyzed in the same manner as in Example 1.
[253]
[254]
Comparative Examples 2 and 3
[255]
[256]
A precursor solution was prepared according to the composition shown in Table 1, and the silica carrier shown in Table 2 was used, but the rest were the same as in Example 1 to prepare each catalyst of Comparative Examples 2 and 3.
[257]
In addition, the ammoxidation process of propylene was performed using the respective catalysts of Comparative Examples 2 and 3 instead of the catalyst of Example 1, and the product was recovered and analyzed in the same manner as in Example 1.
[258]
[259]
Comparative Example 4
[260]
[261]
A catalyst of Comparative Example 4 was prepared in the same manner as in Comparative Example 1, except that a precursor solution was prepared according to the composition shown in Table 1, and the silica carrier described in Table 2 was used.
[262]
In addition, after performing the ammoxidation process of propylene using the catalyst of Comparative Example 1 instead of the catalyst of Comparative Example 1, the product was recovered and analyzed in the same manner as in Comparative Example 1.
[263]
[264]
Comparative Example 5
[265]
[266]
Using the silica carrier shown in Table 1 below, and carrying out the supporting process in consideration of the metal oxide composition shown in Table 2 and the compounding ratio thereof with the silica carrier, the rest was the same as in Example 1 to prepare the catalyst of Comparative Example 5 prepared.
[267]
In addition, the ammoxidation process of propylene was performed using the catalyst of Comparative Example 5 instead of the catalyst of Example 1, and the product was recovered and analyzed in the same manner as in Example 1.
[268]
[269]
[Table 1]
division Mo precursor solution Dissimilar metal precursor solution Distilled water
SiO 2
citric acid Mo Bi Fe Co Ni K HNO 3 H 3 PO 4
Example 1 5.30 10.59 1.82 2.99 9.49 0.00 0.35 2.29 0 45.74 18.30
Example 2 5.30 10.59 1.82 2.99 9.49 0.00 0.35 2.29 0 45.74 18.30
Example 3 5.30 10.59 1.82 2.99 9.49 0.00 0.35 3.38 0 67.59 27.04
Example 4 5.30 10.59 1.82 2.99 9.49 0.00 0.35 4.51 0 90.12 36.05
Example 5 5.30 10.59 2.91 2.02 6.40 0.00 0.02 2.18 0 43.61 17.45
Example 6 5.30 10.59 2.18 3.03 9.46 1.60 0.05 2.38 0 47.58 19.03
Example 7 5.30 10.59 2.43 6.06 6.55 3.64 0.05 2.47 0 49.33 19.73
Comparative Example 1 5.30 10.59 1.82 2.99 9.49 0.00 0.35 1.13 0 22.53 22.53
Comparative Example 2 5.30 10.59 1.82 2.99 9.49 0.00 0.35 2.29 0 45.74 18.30
Comparative Example 3 5.30 10.59 1.82 2.99 9.49 0.00 0.35 2.29 0 45.74 18.30
Comparative Example 4 5.30 10.59 2.43 6.06 6.55 3.64 0.05 1.20 0.25 24.49 24.49
Comparative Example 5 4.41 8.83 48.51 0.00 0.00 0.00 0.00 1.20 0 52.17 52.17
[270]
In Table 1, Mo is (NH 4 ) 6 Mo 7 O 24 , Bi is Bi(NO 3 ) 3 ·5H 2 O, Fe is Fe(NO 3 ) 2 ·9H 2 O, Co is Co ( NO 3 ) 2 ·6H 2 O, Ni is Ni(NO 3 ) 2 ·6H 2 O, and K is KNO 3 .
[271]
[272]
[Table 2]
division quite Catalyst composition carrier
Active substance (metal oxide)
content and composition carrier content product name
Example 1 impregnation 33wt% (Mo 12 Bi 0.75 Fe 1.48 Co 6.52 K 0.7 O x ) 67 wt% D60-120A
Example 2 impregnation 33wt% (Mo 12 B i0.75 Fe 1.48 Co 6.52 K 0.7 O x ) 67 wt% Silica gel 60 (Merk)
Example 3 impregnation 25wt% (Mo 12 Bi 0.75 Fe 1.48 Co 6.52 K 0.7 O x ) 75 wt% D60-60A(N)
Example 4 impregnation 20wt% (Mo 12 B i0.75 Fe 1.48 Co 6.52 K 0.7 O x ) 80 wt% D60-60A(N)
Example 5 impregnation 33wt% (Mo 12 Bi 1.2 Fe 1.0 Co 4.4 K 0.03 O x ) 67 wt% D60-60A(N)
Example 6 impregnation 33wt% (Mo 12 Bi 0.9 Fe 1.5 Co 6.5 Ni 1.1 K 0.1 O x ) 67 wt% D60-60A(N)
Example 7 impregnation 33wt% (Mo 12 Bi 1.0 Fe 3.0 Co 4.5 Ni 2.5 K 0.1 O x ) 67 wt% D60-60A(N)
Comparative Example 1 sol-gel method 50wt% (Mo 12 Bi 0.75 Fe 1.48 Co 6.52 K 0.7 O x ) 50 wt% LUDOX_AS40 (Grace)
Comparative Example 2 impregnation 33wt% (Mo 12 Bi 0.75 Fe 1.48 Co 6.52 K 0.7 O x ) 67 wt% Q-23 (Wakogel)
Comparative Example 3 impregnation 33wt% (Mo 12 Bi 0.75 Fe 1.48 Co 6.52 K 0.7 O x ) 67 wt% SP948 (Grace)
Comparative Example 4 sol-gel method 33wt% (Mo 12 Bi 1.0 Fe 3.0 Co 4.5 Ni 2.5 K 0.1 P 0.5 O x ) 67 wt% LUDOX_AS40 (Grace)
Comparative Example 5 impregnation 33wt%(Bi2O 3 MoO 3 ) 67 wt% D60-60A(N)
[273]
[274]
[275]
Experimental Example 1: Analysis of silica carrier
[276]
[277]
Each silica carrier used in Examples and Comparative Examples was analyzed according to the following analysis method, and the analysis results are shown in Table 3 below:
[278]
[279]
Apparent density : Place the sample in a free-fall method in a container with a volume of 3 cm 3 (cc), add or subtract the amount of sample so that the surface of the sample in the container is in a straight line with the surface of the container, and then weigh the sample in the container Measure and divide this by the volume of the container to obtain the apparent density of the sample.
[280]
[281]
Average pore diameter : Using a BET specific surface area measuring device (manufacturer: BEL Japan, device name: BELSORP_Mini), the adsorption amount measured up to 0.03 and the relative pressure (P/P0) measured up to 1 under liquid nitrogen temperature (77K) The pore size was measured from the BJH equation using the desorption amount.
[282]
[283]
D50 particle size : Dv can be measured using a laser diffraction method. Specifically, each silica carrier of Examples and Comparative Examples was introduced into a particle size measuring device (Microtrac, Blue wave) using a laser diffraction method, and the particle size distribution was measured by measuring the diffraction pattern difference according to the particle size when the particles pass through the laser beam. Calculate. In the measuring device, the value of D50 was obtained by calculating the particle diameter at the point at which it became 50% of the cumulative volume distribution according to the particle diameter.
[284]
[285]
Ammonia (NH 3 ) desorption amount : About 0.1 g of catalyst is filled in a U-shaped quartz tube, a U-shaped reactor is connected to the device, and then the temperature is raised from room temperature by using helium gas (50 cc/min) at a rate of 10 ℃/min After raising the temperature to about 400 ℃ by raising the temperature to about 400 ℃, holding for about 1 hour at 400 ℃ proceed with pretreatment. This is to remove organic matter remaining in the catalyst.
[286]
After the pretreatment is completed, NH 3 is adsorbed at about 100° C. with 5% NH 3 /He (50 cc/min) for 1 hour . While flowing He at the same temperature, the physically adsorbed NH 3 is removed, the temperature is raised to 800° C., and the desorbed NH 3 is measured.
[287]
[288]
[Table 3]
division carrier properties
product name Apparent density pore average diameter D50 particle size Ammonia
desorption amount
Example 1 D60-120A(N) 0.32 g/cc 12 nm 70 μm 0.98 mmol/g
Example 2 Silica gel 60 (Merk) 0.62 g/cc 4.8 nm 56 μm 0.86 mmol/g
Example 3 D60-60A(N) 0.49 g/cc 5.8 nm 61 μm 1.00 mmol/g
Example 4 D60-60A(N) 0.49 g/cc 5.8 nm 61 μm 1.00 mmol/g
Example 5 D60-60A(N) 0.49 g/cc 5.8 nm 61 μm 1.00 mmol/g
Example 6 D60-60A(N) 0.49 g/cc 5.8 nm 61 μm 1.00 mmol/g
Example 7 D60-60A(N) 0.49 g/cc 5.8 nm 61 μm 1.00 mmol/g
Comparative Example 1 LUDOX_AS40 (Grace) - <1 nm 20 nm -
Comparative Example 2 Q-23 (Wakogel) 1.1 g/cc 1.5 nm 70 μm 1.43 mmol/g
Comparative Example 3 SP948 (Grace) 0.2 g/cc 16 nm 55 μm 0.72 mmol/g
Comparative Example 4 LUDOX_AS40 (Grace) 0.49 g/cc 5.8 nm 20 nm -
Comparative Example 5 D60-60A(N) 0.49 g/cc 5.8 nm 61 μm 1.00 mmol/g
[289]
[290]
Experimental Example 2: Catalyst Analysis
[291]
[292]
Each catalyst of Examples and Comparative Examples was analyzed according to the following analysis method, and the analysis results are shown in Table 4 below. For reference, the active material (metal oxide) content and composition, the apparent density of the carrier and the average pore diameter are also listed in Table 4 below:
[293]
[294]
Measurement of D10, D50 and D90 : Dv can be measured using a laser diffraction method. Specifically, each catalyst of Examples and Comparative Examples is introduced into a particle size measuring device (Microtrac, Blue wave) using a laser diffraction method, and the particle size distribution is calculated by measuring the diffraction pattern difference according to the particle size when the particles pass through the laser beam. do. In the measuring device, by calculating the particle diameter at the point where it becomes 10%, 50%, and 90% of the cumulative volume distribution according to the particle size, the values ​​of D10, D50 and D90 are obtained, and the particle size distribution diagram ((D90-D10)/ value of D50) can also be output.
[295]
[296]
Attrition loss : Based on the ASTM9797-00 method, 50g of catalyst (W0) is filled in a vertical inner tube with an inner diameter of 35mm and a height of 710mm, and then N 2 gas is flowed at 10L/min, after 5 hours The weight (W) of the catalyst collected in the fine filter was measured, and the abrasion resistance (attrition loss) was measured using the following equation.
[297]
Wear resistance (attrition loss) (%) = (W0)/WX 100
[298]
[299]
[Table 4]
division quite Active substance (metal oxide)
content and composition carrier Catalyst properties
Apparent
Density pore
average diameter Catalyst
(D90-D10)/D50 Attrition loss
(ASTM_5hrs)
Example 1 impregnation 33wt% (Mo 12 Bi 0.75 Fe 1.48 Co 6.52 K 0.7 O x ) 0.32 g/cc 12 nm 0.82 2.5%
Example 2 impregnation 33wt% (Mo 12 B i0.75 Fe 1.48 Co 6.52 K 0.7 O x ) 0.62 g/cc 4.8 nm 0.53 0.7%
Example 3 impregnation 25wt% (Mo 12 Bi 0.75 Fe 1.48 Co 6.52 K 0.7 O x ) 0.49 g/cc 5.8 nm 0.62 1.5%
Example 4 impregnation 20wt% (Mo 12 B i0.75 Fe 1.48 Co 6.52 K 0.7 O x ) 0.49 g/cc 5.8 nm 0.58 1.4%
Example 5 impregnation 33wt% (Mo 12 Bi 1.2 Fe 1.0 Co 4.4 K 0.03 O x ) 0.49 g/cc 5.8 nm 0.61 2.8%
Example 6 impregnation 33wt% (Mo 12 Bi 0.9 Fe 1.5 Co 6.5 Ni 1.1 K 0.1 O x ) 0.49 g/cc 5.8 nm 0.61 2.8%
Example 7 impregnation 33wt% (Mo 12 Bi 1.0 Fe 3.0 Co 4.5 Ni 2.5 K 0.1 O x ) 0.49 g/cc 5.8 nm 0.60 4.6%
Comparative Example 1 sol-gel method 50wt% (Mo 12 Bi 0.75 Fe 1.48 Co 6.52 K 0.7 O x ) - <1 nm 2.3 10.2%
Comparative Example 2 impregnation 33wt% (Mo 12 Bi 0.75 Fe 1.48 Co 6.52 K 0.7 O x ) 1.1 g/cc 1.5 nm 4.2 5.2%
Comparative Example 3 impregnation 33wt% (Mo 12 Bi 0.75 Fe 1.48 Co 6.52 K 0.7 O x ) 0.2 g/cc 16 nm 0.86 18%
Comparative Example 4 sol-gel method 33wt% (Mo 12 Bi 1.0 Fe 3.0 Co 4.5 Ni 2.5 K 0.1 P 0.5 O x ) 0.49 g/cc 5.8 nm 3.2 14.3%
Comparative Example 5 impregnation 33wt%(Bi 2 O 3 MoO 3 ) 0.49 g/cc 5.8 nm 4.8 23%
[300]
In Table 4, the catalysts of Examples 1 to 7 have a narrower particle size distribution and a smaller wear rate than the catalysts of Comparative Examples 1 to 5.
[301]
[302]
In particular, in relation to the catalysts of Comparative Examples 1 and 4 prepared by the sol-gel method, the impregnation method used to prepare the catalysts of Examples 1 to 7 forms a structure in which a metal oxide is supported on a silica carrier, so that the particle size It can be seen that it is an advantageous method for preparing a catalyst having a narrow distribution and excellent wear resistance.
[303]
[304]
However, although the catalysts of Comparative Examples 2 and 3 were prepared by the impregnation method, a wide particle size distribution and high wear loss appeared.
[305]
As the catalyst of Comparative Example 2 uses a silica carrier having a small pore diameter of 1.5 nm, a large amount of metal oxide cannot be impregnated into the small pores of the silica carrier in the supporting process, and a large amount formed by the non-impregnated metal oxide The particle size distribution is wide and the wear resistance is inferior.
[306]
On the other hand, each catalyst of Comparative Example 3 was easily pulverized because the apparent density and durability were lowered by using a silica carrier having a large pore diameter of 16 nm.
[307]
[308]
Although the catalyst of Comparative Example 5 was also prepared by the impregnation method, a wide particle size distribution and high wear loss appeared.
[309]
The catalyst of Comparative Example 5 showed a wide particle size distribution and poor wear resistance due to the influence of a metal oxide containing only Mo and Bi as active metals, despite using a silica carrier having a pore diameter and an apparent density within an appropriate range, respectively. .
[310]
[311]
On the other hand, the catalysts of Examples 1 to 7 use a silica carrier having a pore diameter and an apparent density within an appropriate range of 2 to 15 nm and 0.3 to 1.0 g/cc, respectively, and Mo and Bi as well as Fe, Co, As a result of supporting a metal oxide further containing an active metal component such as K on the silica carrier, the particle size distribution is narrow and the abrasion resistance is excellent.
[312]
In particular, the catalysts of Examples 1 to 7 showed a uniform particle size distribution with (D90-D10)/D50 of 2 or less, specifically 0.85 or less, and showed a wear loss according to the ASTM9797-00 method of 10% or less, specifically 5 % or less.
[313]
[314]
Experimental Example 3: Analysis of ammoxidation products of propylene
[315]
[316]
Each ammoxidation product of Examples and Comparative Examples was analyzed using chromatography (Gas chromatography, manufacturer: Agilent machine name: HP 6890 N) equipped with FID (Flame Ionization Detector and TCD (Thermal Conductivity Detector)).
[317]
Specifically, products such as ethylene (ehthlene), hydrogen cyanide, acetaldehyde, acetonitrile, acetonitrile (Acrylonitrile) were analyzed by FID, and NH 3 , O 2 , By analyzing gas products such as CO and CO 2 and unreacted propylene, the number of moles of propylene reacted in Examples and Comparative Examples and the number of moles of ammoxidation products were obtained.
[318]
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 5 shows.
[319]
For reference, the active material (metal oxide) content and composition, the apparent density of the carrier and the average pore diameter are also listed in Table 5 below:
[320]
[321]
[Equation 1]
[322]
Conversion of propylene (%)
[323]
=100*(number of moles of ammoxidation of reacted propylene)/(number of moles of propylene supplied)
[324]
[Equation 2]
[325]
Selectivity of acrylonitrile (%)
[326]
=100*(number of moles of acrylonitrile produced)/(number of moles of reacted propylene)
[327]
[Equation 3]
[328]
Yield of acrylonitrile (%)
[329]
=100*(number of moles of acrylonitrile produced)/(number of moles of propylene supplied)
[330]
[331]
[Table 5]
division quite Active substance (metal oxide)
content and composition carrier
Analysis of propylene ammoxidation products
Apparent
Density pore
average diameter Propylene
conversion (%) Acrylonitrile
selectivity (%) Acrylonitrile
Yield (%)
Example 1 impregnation 33wt% (Mo 12 Bi 0.75 Fe 1.48 Co 6.52 K 0.7 O x ) 0.32 g/cc 12 nm 64 70 45
Example 2 impregnation 33wt% (Mo 12 B i0.75 Fe 1.48 Co 6.52 K 0.7 O x ) 0.62 g/cc 4.8 nm 62 68 42
Example 3 impregnation 25wt% (Mo 12 Bi 0.75 Fe 1.48 Co 6.52 K 0.7 O x ) 0.49 g/cc 5.8 nm 58 69 40
Example 4 impregnation 20wt% (Mo 12 B i0.75 Fe 1.48 Co 6.52 K 0.7 O x ) 0.49 g/cc 5.8 nm 57 68 39
Example 5 impregnation 33wt% (Mo 12 Bi 1.2 Fe 1.0 Co 4.4 K 0.03 O x ) 0.49 g/cc 5.8 nm 67 85 57
Example 6 impregnation 33wt% (Mo 12 Bi 0.9 Fe 1.5 Co 6.5 Ni 1.1 K 0.1 O x ) 0.49 g/cc 5.8 nm 67 85 57
Example 7 impregnation 33wt% (Mo 12 Bi 1.0 Fe 3.0 Co 4.5 Ni 2.5 K 0.1 O x ) 0.49 g/cc 5.8 nm 42 88 37
Comparative Example 1 sol-gel method 50wt% (Mo 12 Bi 0.75 Fe 1.48 Co 6.52 K 0.7 O x ) - <1 nm 14 64 9
Comparative Example 2 impregnation 33wt% (Mo 12 Bi 0.75 Fe 1.48 Co 6.52 K 0.7 O x ) 1.1 g/cc 1.5 nm 5 60 3
Comparative Example 3 impregnation 33wt% (Mo 12 Bi 0.75 Fe 1.48 Co 6.52 K 0.7 O x ) 0.2 g/cc 16 nm 80 80 64
Comparative Example 4 sol-gel method 33wt% (Mo 12 Bi 1.0 Fe 3.0 Co 4.5 Ni 2.5 K 0.1 P 0.5 O x ) 0.49 g/cc 5.8 nm 12 58 7
Comparative Example 5 impregnation 33wt%Bi 2 O 3 MoO 3 0.49 g/cc 5.8 nm 10 50 5
[332]
[333]
In Table 5, the catalysts of Examples 1 to 7, compared to the catalysts of Comparative Examples 1, 2, 4 and 5, have significantly higher propylene conversion, selectivity and yield of acrylonitrile.
[334]
[335]
When combined with the results of Table 4, it can be seen that the preparation of a catalyst having a narrow particle size distribution and excellent wear resistance contributes to remarkably increasing the conversion rate of propylene, selectivity of acrylonitrile, and yield.
[336]
[337]
However, the catalyst of Comparative Example 3 was prepared using a silica carrier having a large pore diameter of 16 nm, and as a result, catalytic activity was high. Accordingly, in the reaction carried out on a laboratory scale, as shown in Table 4 above, it was possible to increase the conversion rate of propylene, the selectivity and the yield of acrylonitrile.
[338]
However, as the pore diameter of the silica carrier is large, the apparent density and durability are lowered, so that it is easily abraded and pulverized in the fluidized bed reactor. Therefore, in the mass production process of acrylonitrile, it is necessary to continuously add a catalyst (make-up), and even if it is added, there is a limit in increasing the yield of acrylonitrile.
[339]
[340]
Therefore, in the mass production process of acrylonitrile, catalyst stability is increased by controlling the pore diameter, apparent density, etc. of the silica carrier within the scope of the above-described embodiment with reference to Examples, and the conversion rate of propylene, acrylonitrile Selectivity and yield may be adjusted to a desired range.
Claims
[Claim 1]
a silica carrier comprising pores having a diameter of 2 to 15 nm and an apparent density of 0.25 to 1.0 g/cc; and a metal oxide supported on the silica carrier and including molybdenum (Mo), bismuth (Bi), and a heterogeneous metal; A catalyst for the ammoxidation of propylene, comprising a.
[Claim 2]
The catalyst for ammoxidation of propylene according to claim 1, wherein the silica carrier includes pores having a diameter of 2 to 13 nm.
[Claim 3]
The catalyst for ammoxidation of propylene according to claim 1, wherein the silica carrier has an apparent density of 0.3 to 1.0 g/cc.
[Claim 4]
The catalyst for ammoxidation of propylene according to claim 1, wherein the silica carrier has a D50 particle diameter of 50 to 150 μm.
[Claim 5]
The ammoxidation of propylene according to claim 1, wherein the silica carrier has an ammonia (NH 3 ) desorption amount of 1.3 mmol/g or less (provided that greater than 0 ) as measured by ammonia temperature elevated desorption method (NH 3 -TPD) dragon catalyst.
[Claim 6]
According to claim 1, wherein the metal oxide, the catalyst for ammoxidation of propylene, which is represented by the following formula (1): [Formula 1] Mo 12 Bi a Fe b A c B d C e O x In the formula (1), A is at least one of Ni, Mn, Co, Zn, Mg, Ca, and Ba, B is at least one of Li, Na, K, Rb, and Cs, and C is Cr, W, B, Al, Ca, and at least one element of V, wherein a to e, and x are each an atom or fraction of an atomic group, a is 0.1 to 5, b is 0.1 to 5, c is 0.01 to 10, and d is 0.01 to 2, e is from 0 to 10, and x is from 24 to 48.
[Claim 7]
The catalyst for ammoxidation of propylene according to claim 6, wherein Chemical Formula 1 is the following Chemical Formula 1-1: [Formula 1-1] Mo 12 Bi a Fe b Co c K d O x In Chemical Formula 1-1 , a to d, and each definition of x is the same as in claim 1.
[Claim 8]
The catalyst for ammoxidation of propylene according to claim 1, wherein the weight ratio of the metal oxide and the silica carrier is 15:85 to 35:65.
[Claim 9]
The method according to claim 1, wherein the catalyst comprises: a silica carrier including second pores; 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.
[Claim 10]
The catalyst for ammoxidation of propylene according to claim 1, wherein the catalyst has a D10 particle size, a D50 particle size, and a D90 particle size that satisfies the relationship of Equation 1: [Formula 1] (D90-D10)/D50 ≤ 2.0
[Claim 11]
The catalyst for ammoxidation of propylene according to claim 1, wherein the catalyst has a wear resistance (attrition loss) of 10% or less according to the ASTM9797-00 method.
[Claim 12]
Preparing a first aqueous precursor solution containing a Mo precursor, preparing a second aqueous precursor solution containing a Bi precursor and a heterogeneous metal precursor, including pores having a diameter of 2 to 15 nm, and having an apparent density Supporting a mixture of the first and second aqueous precursor solutions on a silica carrier of 0.25 to 1.0 g/cc, drying the silica carrier on which the mixture of the first and second aqueous precursor solutions is supported, and the A method for preparing a catalyst for ammoxidation of propylene, comprising the step of calcining the dried material.
[Claim 13]
13. The method of claim 12, wherein the second aqueous precursor solution comprises: Bi precursor, Fe precursor, A precursor (A = one or more of Ni, Mn, Co, Zn, Mg, Ca, and Ba), and B precursor (B = Li, Na, K, Rb, and one or more elements of Cs) comprising the step of preparing a second precursor aqueous solution, the method for producing a catalyst for ammoxidation of propylene.
[Claim 14]
According to claim 12, In the step of preparing the second aqueous precursor solution, Bi precursor, Fe precursor, Co precursor, and the preparation of a catalyst for ammoxidation of propylene to prepare a second aqueous precursor solution comprising a K precursor Way.
[Claim 15]
According to claim 12, In the step of preparing the second aqueous precursor solution, to prepare a second precursor aqueous solution further comprising a C precursor (one or more elements of Cr, W, B, Al, Ca, and V) , A method for producing a catalyst for the ammoxidation of propylene.
[Claim 16]
The method of claim 12, wherein in the mixture of the first and second aqueous precursor solutions, the molar ratio of metal satisfies the stoichiometric molar ratio of Formula 1 below: [Formula 1] Mo 12 Bi a Fe b A c B d C e O x In Formula 1, A is at least one of Ni, Mn, Co, Zn, Mg, Ca, and Ba, and B is Li, Na, K, Rb , and one or more elements of Cs, C is one or more elements of Cr, W, B, Al, Ca, and V, wherein a to e, and x are the fraction of atoms or groups of atoms, and a is 0.1 to 5; , b is 0.1 to 5, c is 0.01 to 10, d is 0.01 to 2, e is 0 to 10, and x is 24 to 48.
[Claim 17]
The method according to claim 12, wherein the drying of the silica carrier on which the mixture of the first and second aqueous precursor solutions is supported comprises: the first step of drying the silica carrier on which the mixture of the first and second aqueous precursor solutions is supported at 120 to 160 mbar. A method for producing a catalyst for ammoxidation of propylene, comprising the steps of vacuum drying, and second vacuum drying the first vacuum-dried material at 30 to 50 mbar.
[Claim 18]
13. The method of claim 12, further comprising the step of thirdly drying the second vacuum-dried material at atmospheric pressure.
[Claim 19]
The method of claim 12, wherein the calcining of the dried material is performed at 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 .