Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
  • B01J23/24—Chromium, molybdenum or tungsten
  • B01J23/30—Tungsten
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J35/00—Catalysts, in general, characterised by their form or physical properties
  • B01J35/70—Catalysts, in general, characterised by their form or physical properties characterised by their crystalline properties, e.g. semi-crystalline
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/08—Heat treatment
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07B—GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR
  • C07B61/00—Other general methods
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C253/00—Preparation of carboxylic acid nitriles
  • C07C253/24—Preparation of carboxylic acid nitriles by ammoxidation of hydrocarbons or substituted hydrocarbons
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C255/00—Carboxylic acid nitriles
  • C07C255/01—Carboxylic acid nitriles having cyano groups bound to acyclic carbon atoms
  • C07C255/06—Carboxylic acid nitriles having cyano groups bound to acyclic carbon atoms of an acyclic and unsaturated carbon skeleton
  • C07C255/07—Mononitriles
  • C07C255/08—Acrylonitrile; Methacrylonitrile

Definitions

• the present invention relates to a catalyst (preferably a catalyst for use in a gas-phase catalytic ammoxidation reaction) and a method for producing the same, as well as a method for producing an unsaturated nitrile.
• Patent Document 1 describes an oxide catalyst used in a gas-phase catalytic ammoxidation reaction of propane or isobutane, the oxide catalyst comprising a composite oxide, the composite oxide comprising a catalytically active species isolated from the composite oxide using aqueous hydrogen peroxide, the catalytically active species having an average composition represented by the following composition formula (1) as measured by STEM-EDX: Composition formula: Mo 1 V a Sb b Nb c W d X e O n ...(1) (X represents one or more elements selected from the group consisting of Te, Ce, Ti, and Ta, a, b, c, and d satisfy the relational expressions 0.050 ⁇ a ⁇ 0.200, 0.050 ⁇ b ⁇ 0.200, 0.100 ⁇ c ⁇ 0.300, 0 ⁇ d ⁇ 0.100, 0 ⁇ e ⁇ 0.100, a ⁇ c, and n is a number determined by the valence of other elements.)"
• Patent Document 2 discloses a catalytic composition for the ammoxidation of propane in a gas phase, the catalytic composition comprising one or more crystalline phases, at least one of which is a first phase having an M1 crystal structure and comprising a mixed metal oxide containing molybdenum (Mo), vanadium (V), antimony (Sb) and niobium (Nb), the first phase having a unit cell volume, a first crystal dimension and a second dimension transverse thereto within the range of 2250 A 3 to 2350 A 3 , with the proviso that the ratio of the first dimension to the second dimension is within the range of 2.5 to 0.7.
• a mixed metal oxide containing molybdenum (Mo), vanadium (V), antimony (Sb) and niobium (Nb) the first phase having a unit cell volume, a first crystal dimension and a second dimension transverse thereto within the range of 2250 A 3 to 2350 A 3 , with the proviso that the ratio of the first dimension to the
• Patent Document 3 describes a method for producing a mixed oxide material containing the elements molybdenum, vanadium, niobium, and tellurium, a) producing a mixture of starting compounds, wherein tellurium is in the +4 oxidation state, comprising molybdenum, vanadium, niobium, and a tellurium-containing starting compound; b) hydrothermally treating the mixture of starting compounds at a temperature between 100° C. and 300° C.
• the present invention aims to provide a catalyst suitable for producing unsaturated nitriles, a method for producing the same, and a method for producing unsaturated nitriles using the catalyst.
• a catalyst comprising a metal oxide containing molybdenum and vanadium The catalyst comprises P1 crystals and P2 crystals, A catalyst, wherein the ratio of the crystal lattice constant in the C-axis direction of the P2 crystal to the crystal lattice constant in the C-axis direction of the P1 crystal is 1.0030 to 1.0100.
• a catalyst comprising a metal oxide containing molybdenum and vanadium The catalyst comprises P1 crystals and P2 crystals, A catalyst, wherein the crystal lattice constant in the C-axis direction of the P2 crystal is 4.0200 ⁇ to 4.0298 ⁇ .
• a catalyst comprising a metal oxide containing molybdenum and vanadium, The catalyst comprises P1 crystals and P2 crystals, A catalyst, wherein the crystal lattice constant in the C-axis direction of the P1 crystal is 3.9900 ⁇ to 4.0080 ⁇ .
• the metal oxide is represented by the following formula (1): Mo 1 V a Sb b Nb c W d X e O n ...(1) [Wherein, X is at least one selected from the group consisting of Te, Ce, Ti and Ta; a is equal to or greater than 0.01 and equal to or less than 1, b is equal to or greater than 0.01 and equal to or less than 1, c is equal to or greater than 0.01 and equal to or less than 1, d is equal to or greater than 0 and equal to or less than 1, e is equal to or greater than 0 and equal to or less than 1, n is a value determined by X and a to e.
• the catalyst according to any one of [1] to [5], [7] preparing a slurry containing molybdenum, vanadium, and a first wet silica; spray drying the slurry to obtain particles; calcining the particles to obtain a catalyst; Including, The following (1) and (2): (1) mixing a second wet silica into the slurry when the pH of the slurry is 3 to 8; (2) In the solid-state 29Si -NMR spectrum of the first wet silica, the ratio of the total area of the Q2 signal and the Q3 signal to the total area of the Q2 signal, the Q3 signal, and the Q4 signal is 12 to 35%; A method for producing a catalyst, which satisfies at least one of the above.
• the present invention provides a catalyst suitable for producing unsaturated nitriles, a method for producing the catalyst, and a method for producing unsaturated nitriles using the catalyst.
• a catalyst according to a first embodiment of the present invention is a catalyst containing a metal oxide containing molybdenum and vanadium, the catalyst comprising P1 crystals and P2 crystals, and a ratio of the crystal lattice constant in the C-axis direction of the P2 crystals (hereinafter also referred to as the "P2-C-axis lattice constant") to the crystal lattice constant in the C-axis direction of the P1 crystals (hereinafter also referred to as the "P1-C-axis lattice constant”) is 1.0030 to 1.0100.
• the catalyst according to the second embodiment of the present invention is a catalyst containing a metal oxide containing molybdenum and vanadium, the catalyst containing P1 crystals and P2 crystals, and the crystal lattice constant in the C-axis direction of the P2 crystals is 4.0200 ⁇ to 4.0298 ⁇ .
• the catalyst according to the third embodiment of the present invention is a catalyst containing a metal oxide containing molybdenum and vanadium, the catalyst containing P1 crystals and P2 crystals, and the crystal lattice constant in the C-axis direction of the P1 crystals is 3.9900 ⁇ to 4.0080 ⁇ .
• the catalysts according to the first to third embodiments will be collectively referred to as the catalyst according to this embodiment.
• the catalyst according to this embodiment can be suitably used in a gas-phase catalytic ammoxidation reaction.
• gas-phase catalytic ammoxidation reaction refers to a reaction in which a hydrocarbon, ammonia, and molecular oxygen are reacted in the gas phase to obtain an unsaturated nitrile.
• the catalyst according to the present embodiment By using the catalyst according to the present embodiment, it is possible to produce an unsaturated nitrile in a high yield.
• the reason for this is assumed to be as follows, but the present invention is not limited to this assumed reason. That is, of the P1 crystals and P2 crystals contained in the catalyst, the P2 crystals tend to activate the raw material hydrocarbon and improve the yield of unsaturated nitriles, whereas the P1 crystals tend to decompose the hydrocarbons and unsaturated nitriles.
• vanadium Since vanadium is involved in such activation and decomposition, when vanadium is present in a large amount in the P2 crystals, the yield of the unsaturated nitrile tends to be improved, whereas when vanadium is present in a large amount in the P1 crystals, the yield of the unsaturated nitrile tends to be reduced.
• vanadium has a smaller atomic radius than molybdenum, so as the amount of vanadium contained in a crystal increases, the lattice constant of the crystal decreases, and as the amount of vanadium contained in a crystal decreases, the lattice constant of the crystal increases.
• the lattice constants of the P2 crystals and the P1 crystals are small and large, not compared with the P2 crystals and the P1 crystals contained in the same catalyst, but compared with the P2 crystals or the P1 crystals contained in different catalysts.Therefore, even if the lattice constant of the P2 crystals contained in the catalyst according to this embodiment is larger than the lattice constant of the P1 crystals contained in the same catalyst, if it is smaller than the lattice constant of the P2 crystals contained in different catalysts, it can be said that the lattice constant of the P2 crystals is small
• the ratio of the P2-C axis lattice constant to the P1-C axis lattice constant is 1.0030 to 1.0100. This means that the lattice constant of the P2 crystal is small and the lattice constant of the P1 crystal is large, and therefore it is expected that the yield of the unsaturated nitrile will be improved.
• the P2-C axis lattice constant is 4.0200 ⁇ to 4.0298 ⁇ , which means that the lattice constant of the P2 crystal is small, and therefore it is expected that the yield of unsaturated nitriles will be improved.
• the P1-C axis lattice constant is 3.9900 ⁇ to 4.0080 ⁇ , which means that the lattice constant of the P1 crystal is large. Therefore, it is assumed that the decomposition of hydrocarbons and unsaturated nitriles is promoted, and the yield of unsaturated nitriles is improved as a result.
• the catalyst according to this embodiment contains P1 crystals and P2 crystals.
• P1 crystal refers to a crystal having peaks at 22.1 ⁇ 0.5°, 28.1 ⁇ 0.5°, 36.1 ⁇ 0.5°, and 45.2 ⁇ 0.5° in an X-ray diffraction pattern.
• P2 crystal means a crystal having peaks at 7.8 ⁇ 0.5°, 8.9 ⁇ 0.5°, 22.1 ⁇ 0.5°, 27.1 ⁇ 0.5°, 35.2 ⁇ 0.5°, and 45.2 ⁇ 0.5° in an X-ray diffraction pattern.
• the X-ray diffraction patterns of the P1 crystals and the P2 crystals can be obtained according to the method described in the Examples.
• the P1-C axis lattice constant and the P2-C axis lattice constant can be determined by Rietveld analysis, specifically, according to the method described in the examples.
• the ratio of the P2-C axis lattice constant to the P1-C axis lattice constant is 1.0030 to 1.0100. From the viewpoint of improving the yield of unsaturated nitriles, the ratio is preferably 1.0037 to 1.0079, more preferably 1.0037 to 1.0075, more preferably 1.0037 to 1.0072, and even more preferably 1.0037 to 1.0060.
• the catalyst according to the second and third embodiments may have this characteristic.
• the P2-C axis lattice constant is 4.0200 ⁇ to 4.0298 ⁇ .
• the P2-C axis lattice constant is preferably 4.0210 ⁇ to 4.0290 ⁇ , more preferably 4.0210 ⁇ to 4.0285 ⁇ , and even more preferably 4.0210 ⁇ to 4.0275 ⁇ .
• the catalyst according to the first and third embodiments may have this characteristic.
• the P1-C axis lattice constant is 3.9900 ⁇ to 4.0080 ⁇ .
• the P1-C axis lattice constant is It is preferably 3.9975 ⁇ to 4.0061 ⁇ , more preferably 3.9980 ⁇ to 4.0053 ⁇ , and even more preferably 3.9988 ⁇ to 4.0053 ⁇ .
• the catalysts according to the first and second embodiments may have this characteristic.
• the amount of P2 crystals relative to the total mass of P1 crystals and P2 crystals is preferably 40% by mass or more, more preferably 46% by mass or more and 100% by mass or less, even more preferably 59% by mass or more and 95% by mass or less, and particularly preferably 70% by mass or more and 90% by mass or less.
• the amount of P2 crystals can be determined by Rietveld analysis, and specifically, can be determined according to the method described in the Examples.
• the metal oxide contained in the catalyst according to the present embodiment contains molybdenum (Mo) and vanadium (V) as metal components.
• the metal oxide may contain additional metal components.
• additional metal components include antimony (Sb), niobium (Nb), tungsten (W), tellurium (Te), cerium (Ce), titanium (Ti) and tantalum (Ta).
• the metal oxide is preferably represented by the following formula (1).
• X is at least one selected from the group consisting of Te, Ce, Ti, and Ta; a is 0.01 or more and 1 or less, preferably 0.01 or more and 0.4 or less, more preferably 0.02 or more and 0.3 or less, b is 0.01 or more and 1 or less, preferably 0.01 or more and 0.4 or less, more preferably 0.02 or more and 0.35 or less, c is 0.01 or more and 1 or less, preferably 0.01 or more and 0.3 or less, more preferably 0.02 or more and 0.25 or less, d is 0 or more and 1 or less, preferably 0 or more and 0.3 or less, more preferably 0 or more and 0.2 or less, e is 0 or more and 1 or less, preferably 0 or more and 0.1 or less, more preferably 0 or more and 0.09 or less, n is a value determined by X and a to e (in
• the metal oxide composition can be obtained according to the method described in the Examples.
• the metal oxide contained in the catalyst according to this embodiment may be supported on a carrier.
• the type of carrier is not particularly limited, but silica is preferred.
• a method for producing a catalyst includes: preparing a first slurry containing molybdenum, vanadium, and a first wet silica; mixing the first slurry with a second wet silica to prepare a second slurry when the pH of the first slurry is 3 to 8; spray drying the second slurry to obtain particles; calcining the particles to obtain a catalyst; including.
• the production method according to the fourth embodiment can produce P2 crystals preferentially, and can produce the catalyst described in the ⁇ Catalyst> section above.
• the reasons for this are assumed to be as follows, but the present invention is not limited to these assumed reasons. That is, in the first slurry, various metal components and the first wet silica are in an aggregated state, and by mixing this with the second wet silica, a slurry in which aggregates and dispersed wet silica exist together can be obtained. By spray drying this, particles with a silica layer formed on the surface can be obtained.
• a reducing gas e.g., ammonia gas
• ammonia gas e.g., ammonia gas
• the silica layer suppresses the penetration of the reducing gas into the inside of the particles, so the formation of P1 crystals is suppressed and instead P2 crystals are easily formed.
• the reducing gas can be generated, for example, from the components (e.g., ammonia) used in the preparation of the slurry during firing.
• the first slurry may contain further metal components in addition to molybdenum and vanadium.
• further metal components include those listed in the ⁇ Catalyst> section above.
• the pH of the first slurry may change over time.
• the pH of the first slurry when mixed with the second wet silica is 3 to 8, preferably 4 to 8, more preferably 5 to 8, and even more preferably 6 to 8.
• P2 crystals are more likely to form.
• the amount of the second wet silica is not particularly limited, but may be, for example, 3 to 70 mass%, 5 to 60 mass%, or 10 to 50 mass% based on the total mass of silica used in the catalyst production.
• the time from mixing the second wet silica to spray drying is preferably within 60 minutes, more preferably within 40 minutes, and even more preferably within 30 minutes. The shorter this time interval, the easier it is for P2 crystals to form.
• the second wet silica refers to the wet silica that is last mixed with the slurry. Therefore, for example, if the wet silica is mixed in three batches, the wet silica mixed the third time is the second wet silica.
• Wet silica is a classification of silica that is the opposite of dry silica, and refers to amorphous silicon dioxide synthesized in liquid. Examples include silica sol, precipitated silica, and silica gel. Dry silica is silicon oxide produced by burning silicon tetrachloride, and the physical and chemical properties of wet silica and dry silica are different.
• a method for producing a catalyst includes: preparing a slurry containing molybdenum, vanadium, and wet silica; spray drying the slurry to obtain particles; calcining the particles to obtain a catalyst; Including, In the solid-state 29 Si-NMR spectrum of the wet silica, the ratio of the total area of the Q2 signal and the Q3 signal to the total area of the Q2 signal, the Q3 signal and the Q4 signal is 12 to 35%.
• the "Q2 signal” is a signal derived from the (HO-) 2 Si(-O-Si) 2 structure.
• the term "Q3 signal” refers to a signal derived from the HO-Si(-O-Si) 3 structure.
• the "Q4 signal” is a signal derived from the Si(-O-Si) 4 structure.
• the Q2 to Q4 signals can be obtained according to the method described in the Examples.
• the production method according to the fifth embodiment can produce P2 crystals preferentially, and can produce the catalyst described in the ⁇ Catalyst> section above.
• the reasons for this are assumed to be as follows, but the present invention is not limited to these assumed reasons.
• the structures corresponding to the Q2 and Q3 signals are easily reactive with metal components due to the presence of hydroxyl groups, so that the metal components are dispersed on the silica surface, preventing the metal components from agglomerating, and the P2 crystals are preferentially formed.
• the ratio of the total area of the Q2 and Q3 signals to the total area of the Q2 to Q4 signals is 12 to 35%, preferably 15 to 35%, and more preferably 20 to 35%.
• This ratio can be adjusted, for example, by changing the pH in the preparation of silica or by changing the particle size of the silica particles.
• the ratio of the total area of the Q2 and Q3 signals tends to increase.
• a method for changing the pH to the basic side there is a method of adding a basic solution such as ammonia water.
• the pH of the wet silica is preferably 12.4 or more, more preferably 12.5 or more.
• the particle size of the silica particles is preferably 19 nm or less, more preferably 16 nm or less.
• d is the average particle size
• s is the specific surface area
• ⁇ is the density of silica (2.2 g/cm 3 ).
• the slurry may contain further metal components in addition to molybdenum and vanadium.
• further metal components include those listed in the ⁇ Catalyst> section above.
• the manufacturing method according to the fourth embodiment and the manufacturing method according to the fifth embodiment may be combined. That is, the use of the second wet silica in the fourth embodiment and the use of the wet silica having a predetermined structure in the fifth embodiment may be combined.
• the method includes preparing a first slurry containing molybdenum, vanadium, and a first wet silica; mixing the first slurry with a second wet silica to prepare a second slurry when the pH of the first slurry is 3 to 8; spray drying the second slurry to obtain particles; calcining the particles to obtain a catalyst; Including, In the method for producing a catalyst, in a solid-state 29Si -NMR spectrum of the first wet silica, the ratio of the total area of the Q2 signal and the Q3 signal to the total area of the Q2 signal, the Q3 signal and the Q4 signal is 12 to 35%.
• the spray drying temperature in the manufacturing methods according to the fourth and fifth embodiments is not particularly limited, but it is preferable that the inlet temperature of the spray drying device is 150 to 300°C, and the outlet temperature is 100 to 160°C.
• the firing temperature in the manufacturing methods according to the fourth and fifth embodiments is not particularly limited, but is preferably 500 to 800°C.
• the firing is preferably carried out under an inert gas (e.g., nitrogen).
• the method for producing an unsaturated nitrile according to the sixth embodiment of the present invention includes a step of obtaining an unsaturated nitrile by a gas-phase catalytic ammoxidation reaction of a hydrocarbon in the presence of a catalyst described in the above ⁇ Catalyst> section. Specifically, the step is a step of obtaining an unsaturated nitrile by reacting a hydrocarbon, ammonia, and molecular oxygen in a gas phase.
• Hydrocarbons used in the manufacturing method according to the sixth embodiment include, for example, propane and isobutane.
• the unsaturated nitrile produced by the manufacturing method according to the sixth embodiment is acrylonitrile when propane is used as the raw material, and is methacrylonitrile when isobutane is used as the raw material.
• the molar ratio of hydrocarbon, ammonia, and molecular oxygen is preferably 1:0.8-2.5:7-12.
• the reaction temperature is not particularly limited, but is preferably 350 to 550°C.
• the reaction pressure is not particularly limited, but is preferably 30 to 50 kPa.
• the [crystal lattice constant in the C-axis direction of the P1 crystals], [crystal lattice constant in the C-axis direction of the P2 crystals], and [amount of P2 crystals] were obtained by Rietveld analysis using measurement data obtained from X-ray diffraction measurements.
• the X-ray diffraction measurement method and Rietveld analysis method are as follows.
• X-ray source CuK ⁇ Detector: LYNXEYE XE (1D mode) Tube voltage: 40 kV Tube current: 40mA DS (divergence slit): 0.3° Solar slit (entrance and reception side): 2.5° Detector width (PSD aperture width): 2.9° Air scatter screen: Used Measurement mode: Two Theta/Theta Mode: PSD high speed scan Time: 0.5 (s) 2 ⁇ /start: 5.0° 2 ⁇ /stop: 80.0° Step width: 0.020°
• Rietveld analysis is a well-known method for estimating crystal structure. It is a method for estimating crystal structure by performing measurement of a certain crystal using an X-ray diffraction device (XRD) and defining the information of the measurement device (optical system) and the crystal structure present in the sample for the XRD data obtained, and then adjusting parameters such as the lattice constant and the proportion of crystalline phases so that the measured data and the calculated pattern match.
• XRD X-ray diffraction device
• the analysis software used was TOPAS (DIFFRAC.TOPAS Version 6) from Bruker AXS.
• Rietveld analysis was performed on the P1 crystal using the structure published in Bulletin de la Societe Chimique de France, 1971, 3459-3463 ("EntryWithCollCode26303" in the ICSD database) as the initial structure, and on the P2 crystal using the structure published in Applied Catalysis A: General, 2007, vol 318, 20, 137-142 ("EntryWithCollCode157165" in the ICSD database) as the initial structure.
• the Rietveld analysis was performed as follows:
• the initial structure listed in the above database was used with some modifications to improve the accuracy of the Rietveld analysis with regard to the type, valence, and occupancy of elements at each site in the structural information.
• the modified initial conditions are shown below.
• fitting means refining each set parameter, such as the lattice constant and the proportion of crystalline phases, so that the calculated pattern matches the measured data.
• [C-axis direction crystal lattice constant of P1 crystal] and [C-axis direction crystal lattice constant of P2 crystal] are obtained by refining the C-axis direction crystal lattice constant of the P1 and P2 crystal structures listed in Tables 1 and 2.
• [Amount of P2 crystal] is obtained by refining the scale of the P1 and P2 crystal structures listed in Tables 1 and 2.
• the refinement conditions for the thermal vibration parameters (BEQ) of each site, the x, y, z coordinates of each site, and the metal occupancy of each site for each of the P1 and P2 structures were set as follows:
• the "Mo3 site” and "V3 site”, “Mo4 site” and “V5 site”, “Mo5 site” and “V7 site”, and “Mo7 site” and “V9 site” are located in the same position on the P2 structure, and refer to sites that differ only in the element type, so the x, y, and z coordinates were specified to be the same (e.g., for the "Mo3 site” and “V3 site”, the respective coordinates were set to the same variables, x1, y1, and z1). Furthermore, variables were set so that the occupancy rates for these sites sum to 1. (e.g., for the "Mo3 site” and “V3 site”, the respective occupancies were set to the variables, n1 and 1-n1).
• the XRD calculation pattern is obtained assuming a certain P1/P2 crystal structure, it can be considered that the [crystal lattice constant of P1 crystal in the C-axis direction], [crystal lattice constant of P2 crystal in the C-axis direction], and [amount of P2 crystal] in the assumed P1/P2 crystals represent the P1/P2 crystals that are actually present in the measured sample.
• Catalyst composition (X-ray Fluorescence (XRF) Measurement)
• the catalyst composition was quantitatively measured by a fundamental parameter (FP) method using fluorescent X-ray analysis (Rigaku Corporation, product name "RINT1000", Cr tube, tube voltage 50 kV, tube current 50 mA).
• FP fundamental parameter
• the catalyst obtained was ground and mixed for two hours using a uniaxial Meno automatic mortar (manufactured by Nitto Kagaku Co., Ltd.), and pressure-molded into a vinyl chloride ring (manufactured by Rigaku Co., Ltd.) using a uniaxial press.
• the pellet obtained was semi-quantitatively analyzed by the fundamental parameter (FP) method, which determines the content from a sensitivity library registered in advance in the software, using a wavelength dispersive X-ray fluorescence analyzer (Rigaku Co., Ltd., product name "RINT1000", Cr tube, tube voltage 50 kV, tube current 50 mA).
• FP fundamental parameter
• the obtained spectrum was subjected to phase correction and baseline correction, and then waveform separation of the Q structure signal was performed using waveform processing software (FT-NMR Data Processing by Personal Computer, by Hiroshi Nakamura, Sankyo Publishing).
• the initial values of the shift positions of the Q4, Q3, and Q2 signals were -111.6 ppm, -101.6 ppm, and -92.4 ppm, and the half-widths were 420 Hz, 330 Hz, and 290 Hz, respectively, and the intensities were set according to the signal shapes.
• Waveform separation was then performed by the least squares method with the shift position, half-width, and intensity as variable parameters.
• a mixed function with a Lorentzian/Gaussian function ratio fixed at 0.5 was used as the function.
• the molar ratio of oxalic acid/niobium in the niobium raw material liquid (B1) was calculated as follows. 10 g of the niobium raw material liquid (B1) was weighed out and placed in a crucible, dried at 120° C. for 2 hours, and then heat-treated at 600° C. for 2 hours. The Nb concentration of the aqueous mixed liquid was calculated from the weight of the solid Nb 2 O 5 obtained by the above process, and was found to be 1.072 mol/kg. In addition, 3 g of the niobium raw material liquid (B1) was weighed out into a 300 mL glass beaker, and 20 mL of hot water at about 80° C.
• niobium raw material liquid (B1) 200.7 g of niobium raw material liquid (B1), 29.3 g of ammonium metatungstate aqueous solution (purity 50%), and a dispersion obtained by dispersing 176 g of powdered silica (fumed silica) in 1584 g of water were added in sequence to the aqueous mixture (A1 '), 40.3 g of 25% ammonia water was added, and the mixture was stirred and aged at 65 ° C. for 2 hours to obtain a mixture with a pH of 4.9. To this was added 77.4 g of silica sol containing 34.1 mass % of SiO2 (second wet silica), and the mixture was stirred and aged for 40 minutes to obtain a precursor slurry (C1).
• the precursor slurry (C1) was fed to a centrifugal spray dryer and dried to obtain microspherical dried particles (D1).
• the drying heat source was air.
• the inlet temperature of the dryer was 210° C., and the outlet temperature was 120° C.
• the obtained dried particles (D1) were classified using a sieve with an opening of 32 ⁇ m to obtain classified dried particles (D1).
• Example 2 to 4 A catalyst was prepared in the same manner as in Example 1, except that the pH of the slurry to which the second wet-processed silica was added and the time from mixing the second wet-processed silica to spray drying were changed as shown in Table 1 below.
• Example 1 A catalyst was prepared in the same manner as in Example 1, except that the second wet-processed silica was not mixed.
• Example 5 A catalyst was prepared in the same manner as in Example 1, except that the pH was adjusted to 12.5 by adding 25% aqueous ammonia before adding the first wet silica.
• Example 6 A catalyst was prepared in the same manner as in Example 1, except that before the addition of the first wet-processed silica, 25% aqueous ammonia was added to adjust the pH to 12.8, and the second wet-processed silica was not added.
• Example 7 A catalyst was prepared in the same manner as in Example 1, except that before the addition of the first wet-processed silica, 25% aqueous ammonia was added to adjust the pH to 13.0, and the second wet-processed silica was not added.
• Example 8 A catalyst was prepared in the same manner as in Example 1, except that before the addition of the first wet-processed silica, 25% aqueous ammonia was added to adjust the pH to 13.2, and the second wet-processed silica was not added.
• Example 9 A catalyst was prepared in the same manner as in Example 1, except that before the addition of the first wet-processed silica, 25% aqueous ammonia was added to adjust the pH to 13.4, and the second wet-processed silica was not added.
• Example 2 A catalyst was prepared in the same manner as in Example 1, except that before the addition of the first wet-processed silica, 25% aqueous ammonia was added to adjust the pH to 12.3, and the second wet-processed silica was not added.
• Example 3 A catalyst was prepared in the same manner as in Example 1, except that the second wet-processed silica was not added.
• Example 4 A catalyst was prepared in the same manner as in Example 1, except that the first wet-processed silica had a large particle size of 20 nm and the second wet-processed silica was not added.
• Example 5 A catalyst was prepared in the same manner as in Example 1, except that the first wet-processed silica had a large particle size of 25 nm and the second wet-processed silica was not added.
• Example 6 A catalyst was prepared in the same manner as in Example 1, except that before the addition of the first wet-processed silica, 25% aqueous ammonia was added to adjust the pH to 13.9, and the second wet-processed silica was not added.
• the yield of acrylonitrile was determined as follows. A gas containing acrylonitrile with a known concentration was analyzed by gas chromatography (GC: Shimadzu Corporation, product name "GC2014”) to obtain a calibration curve, and then a gas generated by the ammoxidation reaction was quantitatively injected into the GC to measure the number of moles of acrylonitrile. The yield of acrylonitrile was calculated from the measured number of moles of acrylonitrile according to the following formula.

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• 2023
  • 2023-12-14 WO PCT/JP2023/044821 patent/WO2024135525A1/ja not_active Ceased
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