JP5694727B2 - Method for producing unsaturated acid or unsaturated nitrile - Google Patents

Description

  The present invention relates to a process for producing a corresponding unsaturated acid or unsaturated nitrile by subjecting propane or isobutane to gas phase catalytic oxidation or gas phase catalytic ammoxidation reaction.

Conventionally, a process for producing a corresponding unsaturated acid or unsaturated nitrile by subjecting propylene or isobutylene to gas-phase catalytic oxidation or gas-phase catalytic ammoxidation reaction is well known, but in recent years, propane has been replaced with propylene or isobutylene. Alternatively, a method for producing a corresponding unsaturated acid or unsaturated nitrile by subjecting isobutane to gas phase catalytic oxidation or gas phase catalytic ammoxidation reaction has attracted attention.
Up to now, when propane or isobutane is subjected to gas phase catalytic oxidation or gas phase catalytic ammoxidation to produce the corresponding unsaturated acid or unsaturated nitrile, the target compound is obtained by adding a molybdenum compound into the reactor during the reaction. Studies have been made on methods for maintaining the yield of the product, and methods for recovering the yield of the target product by impregnating, calcining, and drying the catalyst again when the catalyst deteriorates due to the reaction.
For example, Patent Document 1 describes a method of adding a molybdenum compound during a gas phase catalytic ammoxidation reaction using a Mo—V—Sb—Nb-based catalyst.
Patent Document 2 describes a method in which an additive such as an antimony compound, a molybdenum compound, a tellurium compound, or a tungsten compound is mixed and reacted with a composite oxide catalyst.
Further, Patent Document 3 describes Mo—V—Sb / Te-based catalysts as tungsten, molybdenum, chromium, zirconium, titanium, niobium, tantalum, vanadium, boron, bismuth, tellurium, palladium, cobalt, nickel, iron, phosphorus, A method of impregnating a solution containing one or more elements selected from the group consisting of silicon, rare earth elements, alkali metals, and alkaline earth metals is described.

JP 2007-308423 A International Publication No. 2009-048533 Pamphlet JP-A-10-28862

However, as a result of studies by the present inventors, when a molybdenum compound is added during the ammoxidation reaction as in the method described in Patent Document 1, the performance of the catalyst can be recovered to a level close to the initial state. It cannot be improved beyond the initial state, and the performance is still insufficient.
In addition, when an additive such as a metal oxide is added to the composite oxide catalyst as in the method described in Patent Document 2, it succeeds in increasing the selectivity of the target product compared to using the original catalyst. However, even by this method, a catalyst showing industrially sufficient selectivity cannot be obtained. Although it is not clear because there is not enough description in the document, the average particle size of the additive to be added is not appropriate, the contact efficiency between the catalyst and the additive is poor, and the amount of incorporation is too small, so the selectivity of the target product Is estimated to be low.
Furthermore, the method described in Patent Document 3 requires equipment for impregnating the catalyst into the solution and the like, and there are problems that the cost increases because the number of steps increases.
In view of the above circumstances, an object of the present invention is to provide a method for producing an unsaturated acid or an unsaturated nitrile with higher selectivity, which does not require complicated steps such as impregnation and drying.

  As a result of intensive studies to achieve the above object, the present inventors have found that a fluidized bed reactor is used when performing a gas phase catalytic oxidation or a gas phase catalytic ammoxidation reaction using a Mo-V-Nb composite oxide catalyst. It has been found that the selectivity of the target compound is increased by adding a tungsten compound having an average particle size in a specific range and bringing the tungsten compound into contact with the catalyst.

That is, the present invention is as follows.
[1]
By subjecting propane or isobutane to a gas phase catalytic oxidation reaction or a gas phase catalytic ammoxidation reaction using a fluidized bed reactor in the presence of a complex oxide catalyst containing Mo, V and Nb, the corresponding unsaturated acid or non-oxidizing catalyst is obtained. A method for producing a saturated nitrile, comprising:
The step of contacting with said complex oxide catalyst tungsten compound having an average particle diameter 1~500μm in the fluidized bed reactor seen including,
The tungsten compound is an ammonium salt, carboxylate, nitrate, carboxylate ammonium salt, peroxocarboxylate salt, ammonium peroxocarboxylate salt, ammonium halide salt, halide, acetylacetonate, alkoxide, triphenylate, and A method for producing an unsaturated acid or an unsaturated nitrile, which is at least one selected from the group consisting of polyoxometalates and tungsten dioxide, tungstic acid, ammonium metatungstate, ammonium paratungstate and tungsten trioxide .
[2]
The method for producing an unsaturated acid or unsaturated nitrile according to the above [1], wherein the composite oxide catalyst contains a composite oxide represented by the following composition formula (1).
_{Mo 1 V a Nb b A c} X d Z e O n (1)
(In Formula (1), Component A represents at least one element selected from Te and Sb, Component X represents at least one element selected from W, Bi, and Mn, and Component Z represents La, At least one element selected from Ce, Pr, Yb, Y, Sc, Sr, and Ba; a, b, c, d, e, and n represent atomic ratios of each element per Mo atom; Is 0.01 ≦ a ≦ 1, b is 0.01 ≦ b ≦ 1, c is 0.01 ≦ c ≦ 1, d is 0 ≦ d ≦ 1, e is 0 ≦ e ≦ 1, and n is a configuration (The number is determined by the valence of the element.)
[3]
The unsaturated acid or unsaturated according to the above [1] or [2], wherein the composite oxide catalyst comprises a composite oxide supported on 20 to 70% by mass of silica in terms of SiO _{2 with} respect to the whole catalyst. Nitrile production method.

  According to the present invention, it is possible to provide a process for producing an unsaturated acid or an unsaturated nitrile that is simpler and has a higher selectivity.

  Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. The present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist.

  In the method for producing an unsaturated acid or unsaturated nitrile according to the present embodiment, propane or isobutane is subjected to gas phase catalytic oxidation reaction or gas phase contact using a fluidized bed reactor in the presence of a composite oxide catalyst containing Mo and Nb. A method for producing a corresponding unsaturated acid or unsaturated nitrile by subjecting to an ammoxidation reaction, wherein a tungsten compound having an average particle size of 1 to 500 μm is brought into contact with the composite oxide catalyst in the fluidized bed reactor. It is a method including.

[1] Method for Producing Complex Oxide Catalyst (a) Complex Oxide Catalyst The complex oxide catalyst in the present embodiment is a complex oxide containing Mo and Nb supported on a support. The composite oxide catalyst used for producing a corresponding unsaturated acid or unsaturated nitrile by gas phase catalytic oxidation or gas phase catalytic ammoxidation reaction from propane or isobutane has a selectivity by the interaction with the tungsten compound described later. From the viewpoint of exhibiting the improvement effect, it is necessary to contain Mo and Nb.

  From the viewpoint of improving the yield of the target compound, the composite oxide preferably contains Mo, V, Nb and component A (A is at least one element selected from Te and Sb). The complex oxide containing Mo, V, Nb and component A is not clear for certain reasons, but easily forms a bronze structure with good crystallinity, and this structure is a catalyst for the oxidation or ammoxidation reaction of propane or isobutane. It seems to work in favor of performance.

From the viewpoint of the selectivity of the target product and the long-term flow reaction, a more preferable composite oxide composition is represented by the following formula (1).
_{Mo 1 V a Nb b A c} X d Z e O n (1)
(In Formula (1), Component A represents at least one element selected from Te and Sb, Component X represents at least one element selected from W, Bi, and Mn, and Component Z represents La, At least one element selected from Ce, Pr, Yb, Y, Sc, Sr, and Ba; a, b, c, d, e, and n represent atomic ratios of each element per Mo atom; Is 0.01 ≦ a ≦ 1, b is 0.01 ≦ b ≦ 1, c is 0.01 ≦ c ≦ 1, d is 0 ≦ d ≦ 1, e is 0 ≦ e ≦ 1, and n is a configuration (The number is determined by the valence of the element.)

  The atomic ratio a of V per Mo atom and the atomic ratio b of Nb are 0.1 to 0.4 and 0.02 from the viewpoint of suppressing the formation of by-products and increasing the selectivity of the target product, respectively. A range of 0.2 is preferable.

  Component A represents at least one element selected from Te and Sb. The atomic ratio c of the component A per Mo atom is preferably in the range of 0.01 to 0.6 from the viewpoint of suppressing the formation of by-products and increasing the selectivity of the target product. A range of 0.4 is more preferable. In general industrial production methods of unsaturated nitriles, the composite oxide catalyst is preferably able to withstand long-term use at 400 ° C. or higher. However, when component A is Te, Te is likely to escape during long-term operation. Tend to be. From this point of view, component A is preferably Sb in the industrial production method of unsaturated nitrile. On the other hand, in the industrial production method of unsaturated acids, the reaction at 400 ° C. or lower is also possible, so the influence of Te escape during long-term operation is small, and Te can also be used suitably.

  Moreover, a / c which is an atomic ratio of V and component A is preferably in the range of 1 to 10 when Te is used from the viewpoint of suppressing the formation of by-products and increasing the selectivity of the target product. When Sb is used, it is preferably in the range of 0.1-1.

  Component X represents at least one element selected from W, Bi, and Mn. The atomic ratio d of the component X per Mo atom is 0 ≦ d ≦ 1 and satisfies 0.001 ≦ d ≦ 0.3 from the viewpoint of suppressing the formation of by-products and increasing the selectivity of the target product. It is preferable. Component X is selected from W, Bi, and Mn from the viewpoint of industrial long-term use, and W is particularly preferable because the yield of the target product tends to increase.

  The component Z represents at least one element selected from La, Ce, Pr, Yb, Y, Sc, Sr, and Ba. When the component Z is uniformly dispersed in the composite oxide, the effect of improving the yield of the target product tends to increase. Component Z is preferably at least one element selected from La, Ce, Pr, and Yb, and Ce is particularly preferable from the viewpoint of the effect of improving the yield of the target product. Further, from the viewpoint of preventing an undesirable reaction in the slurry by the component Z as taught in JP-A-11-244702, the atomic ratio e of the component Z per Mo atom is 0.001 ≦ e <1. It is preferable to satisfy, more preferably 0.001 ≦ e <0.1, and still more preferably 0.002 ≦ e <0.01.

The composite oxide catalyst in the present embodiment is obtained by supporting the composite oxide described above on a carrier. The carrier on which the composite oxide is supported preferably has silica as a main component. When the composite oxide is supported on a carrier mainly composed of silica, it tends to have high mechanical strength, and is suitable for gas phase catalytic oxidation reaction or gas phase catalytic ammoxidation reaction using a fluidized bed reactor. It is. When the support is mainly composed of silica, the content of silica is preferably 20 to 70% by mass in terms of SiO _{2 with} respect to the entire catalyst including the composite oxide and the support, and is 30 to 60% by mass. More preferably.
The content of silica is preferably 20% by mass or more based on the whole catalyst from the viewpoint of strength and prevention of pulverization. When the silica content is less than 20% by mass, stable operation is difficult in industrial use of the composite oxide catalyst, and it is necessary to replenish the lost composite oxide catalyst, which is not economically preferable. .
On the other hand, from the viewpoint of obtaining a sufficient amount of catalyst by obtaining sufficient activity, the content of silica is preferably 70% by mass or less based on the entire catalyst. In particular, in the case of a fluidized bed, when the silica content is 70% by mass or less, the specific gravity of the composite oxide catalyst is appropriate, and it becomes easy to make a good fluidized state.

(B) Production of Composite Oxide Catalyst The composite oxide catalyst in the present embodiment is produced, for example, by the following three steps.
(1) Step of preparing raw material preparation liquid by preparing raw materials (2) Step of drying raw material preparation liquid obtained in step (1) to obtain a catalyst precursor (3) Catalyst obtained in step (2) Step of calcining the precursor to obtain a composite oxide catalyst Here, “preparation” is to dissolve or disperse the raw material of the catalyst constituent element in a solvent. Although it does not specifically limit as a solvent, It is preferable to use water.
The “raw material” refers to a compound containing a constituent element of the composite oxide catalyst. It does not specifically limit as a raw material, For example, the following compounds can be used.

As the raw material for Mo and V, but are not limited to, respectively, be used ammonium heptamolybdate _{[(NH 4) 6 Mo 7} O 24 · 4H 2 O] and ammonium metavanadate [NH ₄ VO _3] suitably it can.

As a raw material of Nb, niobic acid, an inorganic acid salt of niobium, and an organic acid salt of niobium can be used, and niobic acid is particularly preferable. Niobic acid is represented by Nb ₂ O ₅ .nH ₂ O and is also referred to as niobium hydroxide or niobium oxide hydrate. Furthermore, it is preferable to use as a Nb raw material liquid having a dicarboxylic acid / niobium molar ratio of 1 to 4. Oxalic acid is preferably used as the dicarboxylic acid.

The raw material of Sb is not particularly limited, but diantimony trioxide [Sb ₂ O ₃ ] is preferable.

The raw material of Te is not particularly limited, but telluric acid [H ₆ TeO ₆ ] is preferable.

  The raw material of component X is not particularly limited as long as it is a substance containing these elements, and a compound containing these elements or a material obtained by solubilizing a metal of these elements with an appropriate reagent can be used. The compounds containing these elements are usually ammonium salts, nitrates, carboxylates, ammonium carboxylates, peroxocarboxylates, ammonium peroxocarboxylates, ammonium halides, halides, acetylacetonates, alkoxides, etc. Preferably, water-soluble raw materials such as nitrates and carboxylates are used.

  The raw material for component Z is not particularly limited as long as it is a substance containing these elements, but a compound containing these elements or a metal obtained by solubilizing these elements with an appropriate reagent can be used. . As compounds containing these elements, nitrates, carboxylates, ammonium carboxylates, peroxocarboxylates, ammonium peroxocarboxylates, ammonium halides, halides, acetylacetonates, alkoxides, etc. are usually used. Preferably, water-soluble raw materials such as nitrates and carboxylates are used.

  The silica raw material contained in the carrier is not particularly limited, and silica sol can be suitably used, but powder silica can also be used for a part or all of the silica raw material. The powder silica is preferably produced by a high heat method. Powdered silica can be easily added to and mixed with the slurry by previously dispersing it in water. There is no restriction | limiting in particular as a dispersion method, A general homogenizer, a homomixer, an ultrasonic vibrator, etc. can be disperse | distributed individually or in combination.

Below, the manufacture example of the preferable complex oxide catalyst containing process (1)-(3) is demonstrated.
(Step (1): Step of preparing raw material preparation liquid by preparing raw materials)
The raw materials of Mo, V, component A, component X, and component Z and, if necessary, other raw material components are added to water and heated to prepare an aqueous mixture (I). At this time, the inside of the container may be a nitrogen atmosphere. Next, the Nb raw material and dicarboxylic acid are heated and stirred in water to prepare a mixed solution (B0). Further, hydrogen peroxide is added to the mixed solution (B0) to prepare an aqueous mixed solution (II). At this time, H ₂ O ₂ / Nb (molar ratio) is 0.5 to 20, preferably 1-10.

  The aqueous mixture (I) and the aqueous mixture (II) are suitably mixed according to the target composition to obtain the aqueous mixture (III). The obtained aqueous mixed liquid (III) is aged in an air atmosphere to obtain a slurry-like raw material preparation liquid.

The aging of the aqueous mixture (III) means that the aqueous mixture (III) is allowed to stand for a predetermined time or is stirred. In the case of producing a composite oxide catalyst industrially, the processing speed of the spray dryer is usually limited, and after a part of the aqueous mixed liquid (III) is spray dried, the spray drying of all the mixed liquid is completed. It takes time. During this time, aging of the liquid mixture that has not been spray-dried is continued. Therefore, the aging time includes not only the aging time before spray drying but also the time from the start to the end of spray drying.
The aging time is preferably 90 minutes to 50 hours, more preferably 90 minutes to 6 hours.
The aging temperature is preferably 25 ° C. or higher from the viewpoint of preventing condensation of Mo components and precipitation of V. Moreover, 65 degreeC or less is preferable from a viewpoint which prevents hydrolysis of the complex containing Nb and hydrogen peroxide from occurring too much, and forms the slurry of a preferable form. Therefore, the aging temperature is preferably 25 ° C. or more and 65 ° C. or less, and more preferably 30 ° C. or more and 60 ° C. or less.
The atmosphere in the container at the time of aging preferably has a sufficient oxygen concentration. If oxygen is not sufficient, there is a possibility that substantial changes in the aqueous mixture (III) are less likely to occur. Accordingly, the gas phase oxygen concentration in the container is preferably 1 vol% or more.
The gas phase oxygen concentration can be measured by a general method, for example, using a zirconia oxygen analyzer. The place where the gas phase oxygen concentration is measured is preferably near the interface between the aqueous mixed liquid (III) and the gas phase. For example, it is preferable to measure the gas-phase oxygen concentration at the same point three times within 1 minute, and use the average value of the three measurement results as the gas-phase oxygen concentration.
Although it does not specifically limit as dilution gas for reducing a gaseous-phase oxygen concentration, Nitrogen, helium, argon, a carbon dioxide, water vapor | steam, etc. are mentioned. Industrially, nitrogen is preferable. The gas for increasing the gas phase oxygen concentration is preferably pure oxygen or air with a high oxygen concentration.

  Aging is considered to cause some change in the redox state of the components contained in the aqueous mixture (III). Some kind of change is also suggested from the fact that a change in the color of the aqueous mixture (III), a change in redox potential, and the like occur during aging. As a result, a difference also appears in the performance of the composite oxide catalyst obtained depending on the presence or absence of aging in an atmosphere having an oxygen concentration of 1 to 25 vol% for 90 minutes to 50 hours. In other words, it is extremely difficult to accurately identify the morphological changes of the components in the liquid during aging, but by producing catalysts with different aging times and evaluating their performance, the aging time applied to the catalyst with good performance Preferably, at this time, it can be inferred that some preferred form of slurry was formed.

  The redox potential of the aqueous mixture (III) is dominated by the potential 600 mV / AgCl of the aqueous raw material liquid (II), and the oxalic acid Nb peroxide and other metal components contained in the aqueous raw material liquid (II) are oxidized in some way. It is believed that the reduction of the potential with time occurs due to the reduction reaction. A preferable redox potential is 450 to 530 mV / AgCl, and more preferably 470 to 510 mV / AgCl.

  From the viewpoint of preventing the oxidation-reduction state in the slurry stage from becoming overoxidized without slowing the progress of the oxidation-reduction reaction that affects any change in the oxidation-reduction state of the components contained in the aqueous mixture (III). The oxygen concentration during aging is preferably 1 vol% or more. On the other hand, from the viewpoint of preventing the oxidation-reduction reaction from proceeding excessively and causing the slurry to become overreduced, the oxygen concentration during the aging is preferably 25 vol% or less. In any case, since oxygen in the gas phase affects the redox state of the slurry, it is necessary to maintain the oxygen concentration within an appropriate range. As for the range of oxygen concentration, 5-23 vol% is more preferable, and 10-20 vol% is still more preferable.

  During ripening, moisture can evaporate and concentration can occur. However, if the aging is carried out in an open system, the evaporation of water inevitably occurs, but the catalyst performance tends to be further improved when carried out in an atmosphere with an oxygen concentration of 1 to 25 vol%.

  When the composite oxide is supported on silica, the raw material preparation liquid is prepared so as to include silica sol. Silica sol can be added as appropriate. Also, a part of the silica sol can be made into an aqueous dispersion of powdered silica, and such an aqueous dispersion of powdered silica can be added as appropriate.

Moreover, when using Sb (antimony) as the component A, it is preferable to add hydrogen peroxide to the liquid containing the component of the aqueous mixed liquid (I) or the aqueous mixed liquid (I) being prepared. At this time, H ₂ O ₂ / Sb (molar ratio) is preferably from 0.01 to 5, and more preferably 0.05 to 4. At this time, it is preferable to continue stirring at 30 ° C. to 70 ° C. for 30 minutes to 2 hours.

(Process (2): Drying process)
A drying process is a process of drying the raw material preparation liquid obtained at the process (1), and obtaining a catalyst precursor. Drying can be performed by a known method, for example, spray drying or evaporation to dryness. Among these, it is preferable to employ spray drying to obtain a fine spherical catalyst precursor. The atomization in the spray drying method can be performed by a centrifugal method, a two-fluid nozzle method, or a high-pressure nozzle method. As the drying heat source, air heated by steam, an electric heater or the like can be used. The dryer inlet temperature of the spray dryer is preferably 150 to 300 ° C. The dryer outlet temperature is preferably 100 to 160 ° C.

(Process (3): Firing process)
The calcining step is a step of calcining the catalyst precursor obtained in the step (2) to obtain a composite oxide catalyst. A rotary furnace (rotary kiln) can be used as the baking apparatus. Although the shape of a baking machine is not specifically limited, If it is tubular, continuous baking can be implemented. The shape of the firing tube is not particularly limited, but is preferably a cylinder. The heating method is preferably an external heating type, and an electric furnace can be suitably used. The size, material, and the like of the firing tube can be selected appropriately depending on the firing conditions and production amount, but the inner diameter is preferably 70 to 2000 mm, more preferably 100 to 1200 mm, and its length. Is preferably 200 to 10000 mm, more preferably 800 to 8000 mm. When impacting the firing device, the thickness of the firing device is preferably 2 mm or more, more preferably 4 mm or more from the viewpoint that the thickness of the firing device is not damaged by the impact, and the impact is sufficient to the inside of the firing device. From the viewpoint of being transmitted to the surface, it is preferably 100 mm or less, more preferably 50 mm or less. The material of the calciner is not particularly limited except that it has heat resistance and has a strength that does not break due to impact, and SUS can be suitably used.

  In the firing tube, a weir plate having a hole in the center for allowing the powder to pass can be provided perpendicular to the flow of the powder to partition the firing tube into two or more areas. By installing the weir plate, it becomes easy to secure the residence time in the firing tube. The number of weir plates may be one or more. The material of the weir plate is preferably metal, and the same material as that of the firing tube can be suitably used. The height of the weir plate can be adjusted according to the residence time to be secured. For example, when supplying powder at 250 g / hr in a rotary furnace having a 150 mm inner diameter and 1150 mm long SUS firing tube, the weir plate is preferably 5 to 50 mm, more preferably 10 to 40 mm, still more preferably 13 to 35 mm. The thickness of the weir plate is not particularly limited, and is preferably adjusted according to the size of the firing tube. For example, in the case of a rotary furnace having a SUS firing tube having an inner diameter of 150 mm and a length of 1150 mm, the thickness of the firing tube is preferably from 0.3 mm to 30 mm, more preferably from 0.5 mm to 15 mm.

  It is preferable to rotate the calcining tube in order to prevent cracking, cracking and the like of the catalyst precursor and to calcine uniformly. The rotation speed of the firing tube is preferably 0.1 to 30 rpm, more preferably 0.5 to 20 rpm, and still more preferably 1 to 10 rpm.

  For the firing of the catalyst precursor, the heating temperature of the catalyst precursor is started from a temperature lower than 400 ° C., and continuously or intermittently raised to a temperature within the range of 550 to 800 ° C. preferable.

  The firing atmosphere may be an air atmosphere or an air circulation, but it is preferable to carry out at least a part of the firing while circulating an inert gas substantially free of oxygen such as nitrogen. The supply amount of the inert gas is 50 N liters or more per 1 kg of the catalyst precursor, preferably 50 to 5000 N liters, more preferably 50 to 3000 N liters (N liter is a standard temperature / pressure condition, that is, 0 ° C., Means liters measured at 1 atm). At this time, the inert gas and the catalyst precursor may be counter-current or co-current, but counter-current contact is preferable in consideration of gas components generated from the catalyst precursor and air mixed in a trace amount together with the catalyst precursor.

  The firing step can be performed even in one stage, but the firing includes pre-stage firing and main firing, and the pre-stage firing is performed in a temperature range of 250 to 400 ° C., and the main firing is performed in a temperature range of 550 to 800 ° C. preferable. The pre-baking and the main baking may be performed continuously, or the main baking may be performed again after the pre-baking is once completed. Moreover, each of pre-stage baking and main baking may be divided into several stages.

  The pre-stage calcination is preferably performed in the range of a heating temperature of 250 to 400 ° C., preferably 300 to 400 ° C. under an inert gas flow. Although it is preferable to hold at a constant temperature within the temperature range of 250 ° C. to 400 ° C., the temperature may vary within the range of 250 ° C. to 400 ° C., or the temperature may be gradually raised or lowered. The holding time of the heating temperature is preferably 30 minutes or more, more preferably 3 to 12 hours.

  The temperature rising pattern until reaching the pre-stage firing temperature may be increased linearly, or the temperature may be increased by drawing an upward or downward convex arc.

  There is no particular limitation on the average rate of temperature increase during the temperature increase until reaching the pre-stage firing temperature, but generally it is about 0.1 to 15 ° C./min, preferably 0.5 to 5 ° C./min, more preferably 1 to 2 ° C./min.

  The main calcination is preferably performed at 550 to 800 ° C., preferably 580 to 750 ° C., more preferably 600 to 720 ° C., and still more preferably 620 to 700 ° C. under an inert gas flow. Although it is preferable to hold at a constant temperature within a temperature range of 620 to 700 ° C, the temperature may fluctuate within the range of 620 to 700 ° C, or the temperature may be gradually increased or decreased. The firing time is 0.5 to 20 hours, preferably 1 to 15 hours. When the calcining tube is divided by a dam plate, the catalyst precursor and / or the composite oxide catalyst pass through at least two, preferably 2 to 20, more preferably 4 to 15 zones in succession. The temperature can be controlled by using one or more controllers, but in order to obtain the desired firing pattern, a heater and a controller can be installed and controlled for each section separated by these weirs. preferable. For example, when seven dam plates are installed so that the length of the portion of the calcination tube entering the heating furnace is equally divided into eight, and the calcination tube divided into eight sections is used, the catalyst precursor and / or the composite oxide It is preferable that the set temperature is controlled by a heater and a controller in which eight zones are installed for each zone so that the catalyst temperature has the desired firing temperature pattern. If desired, an oxidizing component (for example, oxygen) or a reducing component (for example, ammonia) may be added to the firing atmosphere under an inert gas flow.

  The temperature rising pattern until reaching the main firing temperature may be increased linearly, or the temperature may be increased by drawing an upward or downward convex arc.

  There is no particular limitation on the average rate of temperature increase during the temperature increase until the main firing temperature is reached, but generally 0.1 to 15 ° C./min, preferably 0.5 to 10 ° C./min, more preferably 1 to 8 ° C / min.

  Moreover, the average temperature-fall rate after completion | finish of this baking is 0.01-1000 degreeC / min, Preferably it is 0.05-100 degreeC / min, More preferably, it is 0.1-50 degreeC / min, More preferably, 0.5- 10 ° C./min. Moreover, it is also preferable to hold once at a temperature lower than the main firing temperature. The temperature to be maintained is 10 ° C., preferably 50 ° C., more preferably 100 ° C. lower than the main firing temperature. The holding time is 0.5 hours or more, preferably 1 hour or more, more preferably 3 hours or more, and further preferably 10 hours or more.

  When the main baking is performed again after the pre-stage baking is once completed, it is preferable to perform a low temperature treatment in the main baking.

  The time required for the low-temperature treatment, that is, the time required for raising the temperature to the firing temperature after reducing the temperature of the catalyst precursor and / or the composite oxide catalyst is the size, thickness, material, It can be appropriately adjusted depending on the catalyst production amount, a series of periods in which the catalyst precursor and / or the composite oxide catalyst are continuously calcined, the fixing speed and the fixing amount, and the like. For example, in the case of using a SUS calcining tube having an inner diameter of 500 mm, a length of 4500 mm, and a wall thickness of 20 mm, preferably within 30 days, more preferably within 15 days, Preferably within 3 days, particularly preferably within 2 days.

  For example, the catalyst precursor is supplied at a speed of 35 kg / hr while rotating at 6 rpm by a rotary furnace having a SUS calcining tube having an inner diameter of 500 mm, a length of 4500 mm, and a wall thickness of 20 mm, and the main calcining temperature is set to 645 ° C. In this case, after the temperature is lowered to 400 ° C., the step of raising the temperature to 645 ° C. can be performed in about one day. In the case of continuous firing for one year, by performing such a low temperature treatment once a month, it is possible to perform firing while stably maintaining the oxide layer temperature.

[2] Method for Producing Unsaturated Acid or Unsaturated Nitrile Propane or isobutane is subjected to gas phase catalytic oxidation or gas phase catalytic ammoxidation reaction using a fluidized bed reactor in the presence of the composite oxide catalyst in the present embodiment. Thus, the corresponding unsaturated acid or unsaturated nitrile can be produced.
The feedstock for propane or isobutane and ammonia does not necessarily have to be high purity, and industrial grade gases can be used.
Air, oxygen-enriched air, or pure oxygen can be used as the supply oxygen source. Further, helium, argon, carbon dioxide gas, water vapor, nitrogen or the like may be supplied as a dilution gas.

The gas phase catalytic oxidation of propane or isobutane can be carried out under the following conditions.
The molar ratio of oxygen supplied to the reaction to propane or isobutane is 0.1 to 6, preferably 0.5 to 4.
The reaction temperature is 300 to 500 ° C, preferably 350 to 450 ° C.
The reaction pressure is 5 × 10 ^{4 to} 5 × 10 ⁵ Pa, preferably 0.5 × 10 ⁵ to 2 × 10 ⁵ Pa.
The contact time is 0.1 to 10 (sec · g / cc), preferably 0.5 to 5 (sec · g / cc). In the present embodiment, the contact time is determined by the following equation.
Contact time (sec · g / cc) = (W / F) × 273 / (273 + T)
Here, W, F, and T are defined as follows.
W = filled catalyst amount (g)
F = Raw material mixed gas flow rate (Ncc / sec) at standard condition (0 ° C., 1.013 × 105 Pa)
T = reaction temperature (° C.)

The gas phase catalytic ammoxidation of propane or isobutane can be carried out under the following conditions.
The molar ratio of oxygen supplied to the reaction to propane or isobutane is 0.1 to 6, preferably 0.5 to 4.
The molar ratio of ammonia to propane or isobutane supplied to the reaction is 0.3 to 1.5, preferably 0.7 to 1.2.
The reaction temperature is 350 to 500 ° C, preferably 380 to 470 ° C.
The reaction pressure is 5 × 10 ^{4 to} 5 × 10 ⁵ Pa, preferably 1 × 10 ^{5 to} 3 × 10 ⁵ Pa.
The contact time is 0.1 to 10 (sec · g / cc), preferably 0.5 to 5 (sec · g / cc).

  In general, conventional methods such as a fixed bed, a fluidized bed, and a moving bed can be adopted as a reaction method for producing an unsaturated acid or unsaturated nitrile. In this embodiment, a tungsten compound is used in the reactor. From the viewpoint of improving the selectivity of the target compound by interaction with the composite oxide catalyst, the fluidized bed reaction is selected. The fluidized bed reaction also has an advantage that reaction heat can be easily removed.

  The gas phase catalytic ammoxidation reaction may be a single flow type or a recycle type.

[3] Method for Adding Tungsten Compound The method for producing an unsaturated acid or unsaturated nitrile in this embodiment includes a step of bringing a tungsten compound having an average particle diameter of 1 to 500 μm into contact with the composite oxide catalyst in a fluidized bed reactor. . The composite oxide catalyst has catalytic activity as it is, but by contacting the tungsten compound with the composite oxide catalyst in the gas phase catalytic oxidation reaction or gas phase catalytic ammoxidation reaction using a fluidized bed reactor, The selectivity of the target compound can be improved. For example, even when the raw material is supplied to the reactor containing the composite oxide catalyst and the gas phase catalytic oxidation reaction or the gas phase catalytic ammoxidation reaction is allowed to proceed, the selectivity of the target compound is not sufficient. The selectivity can be improved from the initial state by adding the tungsten compound while the reaction proceeds.

As described above, tungsten may be contained as an element constituting the composite oxide catalyst. Even in this case, the selectivity of the target compound can be increased by adding the tungsten compound to the fluidized bed reactor. Can be improved. The reason for this is that the tungsten compound added to the reactor is involved in the modification near the surface of the composite oxide and acts differently from the tungsten component that has entered the crystal of the composite oxide catalyst. The present inventors presume.
More specifically, when a tungsten compound is added to the fluidized bed reactor, the composite oxide catalyst and the tungsten compound come into contact with each other, and the tungsten compound diffuses to the surface of the composite oxide in the catalyst by a solid-phase reaction, such as Mo. It is assumed that an exchange reaction with the metal element occurs. The present inventors consider that this exchange reaction contributes to improvement of the selectivity of the target compound.

Examples of the method of adding the tungsten compound into the reactor include the following two methods (1) and (2), and the latter (2) can be further classified into continuous addition and intermittent addition.
(1) Method of adding to fluidized bed reactor before gas phase catalytic oxidation reaction or gas phase catalytic ammoxidation reaction (2) Method of adding to fluidized bed reactor during gas phase catalytic oxidation reaction or gas phase catalytic ammoxidation reaction (Continuous / intermittent addition)

(Method (1): Method of adding before reaction)
Tungsten compounds include ammonium salts, nitrates, carboxylates, carboxylic acid ammonium salts, peroxocarboxylates, peroxocarboxylic acid ammonium salts, ammonium halide salts, halides, acetylacetonates, alkoxides, triphenyl compounds, polyoxo Tungsten salts such as metalate and polyoxometalate ammonium salt; tungsten trioxide, tungsten dioxide, tungstic acid, ammonium metatungstate, ammonium paratungstate, silicotungstic acid, caythanst molybdic acid, cayvanadotungstic acid, etc. These powder raw materials can be used. Among the above, tungsten trioxide and ammonium metatungstate can be preferably used from the viewpoint of little adverse effect of the tungsten compound on the target compound. In addition, about the complex oxide catalyst containing much tungsten, a part of the complex oxide catalyst may function as the tungsten compound in the present embodiment.

  If the tungsten compound is too large, it stays at the bottom of the reactor and does not come into contact with the catalyst. If it is too small, the tungsten compound may blow off and go out of the reactor. Therefore, the average particle size is 1 to 500 μm, preferably It is 5-300 micrometers, More preferably, it is 10-250 micrometers, More preferably, it is 20-150 micrometers. Here, the average particle diameter of a tungsten compound means the value which measured the tungsten compound baked at 300-600 degreeC for 3 to 5 hours with the particle diameter measuring apparatus (LS230 by BECKMANCOULTER).

  The means for adding the tungsten compound into the reactor is not particularly limited, but the tungsten compound can be supplied by being fed from a hopper or the like outside the reactor via a pipe to the catalyst rich layer portion of the fluidized bed reactor. In this case, air, inert gas, or the like is used as the gas used for pressure feeding.

(Method (2): Method of adding during reaction)
The same tungsten compound as that used in the method (1) can be used. Regarding the amount of tungsten compound added during the reaction, depending on the reactor equipment, operating conditions, type of tungsten compound, and combinations of these, the shape of the tungsten compound may be damaged and go out of the reactor. It is necessary to arbitrarily adjust the addition amount according to the catalyst composition in the reactor.

  Also in the case of the method (2), for the same reason as described above, the average particle size of the tungsten compound is 1 to 500 μm, preferably 5 to 300 μm, more preferably 10 to 250 μm, and still more preferably 20 to 150 μm.

  As the means for addition into the reactor, the same means as described above can be used. The tungsten compound may be added alone or in a mixture with a catalyst and a molybdenum compound.

  When a tungsten compound is added during the reaction, it may be added continuously or intermittently. Here, continuous addition refers to a technique in which tungsten is continuously added every day, and intermittent addition refers to a technique in which addition is performed every several days.

  Hereinafter, the present embodiment will be described in more detail with reference to examples and comparative examples, but the scope of the present embodiment is not limited to these examples.

In Examples and Comparative Examples, propane conversion, acrylonitrile selectivity, acrylonitrile yield, acrylic acid selectivity, and acrylic acid yield are in accordance with the following definitions.
Propane (PN) conversion (%) = (moles of propane reacted) / (moles of propane fed) × 100
Acrylonitrile (AN) selectivity (%) = (number of moles of acrylonitrile produced) / (number of moles of reacted propane) × 100
Acrylonitrile (AN) yield (%) = (Mole number of acrylonitrile produced) / (Mole number of supplied propane) × 100
Acrylic acid (AA) selectivity (%) = (number of moles of produced acrylic acid) / (number of moles of reacted propane) × 100
Acrylic acid (AA) yield (%) = (number of moles of acrylic acid produced) / (number of moles of propane supplied) × 100

The average particle size was measured as follows.
10 g of a tungsten compound was calcined at 500 ° C. for 3 hours, mixed with about 10 g of water in about 10 cc of water, and an appropriate amount of the suspension was placed in a particle size measuring device (LS230 manufactured by BECKMANCOULTER) and measured.

(Preparation of niobium mixture)
A niobium mixed solution was prepared by the following method.
In 10 kg of water, 0.956 kg of niobic acid containing 80.0% by mass as Nb ₂ O ₅ and 3.291 kg of oxalic acid dihydrate [H ₂ C ₂ O ₄ .2H ₂ O] were mixed. The molar ratio of the charged oxalic acid / niobium was 5.0, and the charged niobium concentration was 0.50 (mol-Nb / Kg-solution). This solution was heated and stirred at 95 ° C. for 2 hours to obtain a mixed solution in which niobium was dissolved. The mixture was allowed to stand and ice-cooled, and then the solid was separated by suction filtration to obtain a uniform niobium mixture. The molar ratio of oxalic acid / niobium in this niobium mixture was 2.75 according to the following analysis.
10 g of this niobium mixed solution was precisely weighed in a crucible, dried overnight at 95 ° C., and then heat treated at 600 ° C. for 1 hour to obtain 0.760 g of Nb ₂ O ₅ . From this result, the niobium concentration was 0.572 (mol-Nb / Kg-solution).
3 g of this niobium mixture was precisely weighed into a 300 mL glass beaker, 200 mL of hot water at about 80 ° C. was added, and then 10 mL of 1: 1 sulfuric acid was added. The obtained mixed liquid was titrated with 1 / 4N KMnO ₄ under stirring while maintaining the liquid temperature at 70 ° C. on a hot stirrer. The end point was a point where a faint pale pink color by KMnO ₄ lasted for about 30 seconds or more. The concentration of oxalic acid was 1.573 (mol-oxalic acid / Kg) as a result of calculation according to the following formula from titration.
2KMnO ₄ + 3H ₂ SO ₄ + 5H ₂ C ₂ O ₄ → K ₂ SO ₄ + 2MnSO ₄ + 10CO ₂ + 8H ₂ O
The obtained niobium mixed solution was used as a niobium mixed solution (B ₀ ) for catalyst preparation described below.

[Example 1]
(Preparation of composite oxide catalyst)
Mixing composition formula was produced by the composite oxide catalyst represented by _{Mo 1 V 0.20 Nb 0.10 Sb 0.20} W 0.05 O n /50.0wt%-SiO 2 as follows.
In 1683 g of water, 411.3 g of ammonium heptamolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O], 54.1 g of ammonium metavanadate [NH ₄ VO ₃ ], and antimony trioxide [Sb ₂ O ₃ ] was added and heated at 95 ° C. for 1 hour with stirring to obtain an aqueous raw material liquid (I).
Aqueous raw material liquid (II) is prepared by adding 66.3 g of hydrogen peroxide containing 30 wt% as H ₂ O _{2 to} 404.4 g of niobium mixed liquid (B ₀ ), and stirring and mixing at room temperature for 10 minutes. did.
After cooling the obtained aqueous raw material liquid (I) to 70 ° C., 735.7 g of silica sol containing 34.0 wt% as SiO ₂ was added, and hydrogen peroxide solution 129 containing 30 wt% as H ₂ O ₂ was further added. .3 g was added and stirring was continued at 55 ° C. for 30 minutes. Next, an aqueous raw material liquid (II), a dispersion in which 53.4 g of a 50 wt% ammonium metatungstate aqueous solution as WO _{3 and} 250 g of powdered silica are dispersed in 3375 g of water are sequentially added to obtain an aqueous mixed liquid (III). Obtained. The aqueous mixed liquid (III) was aged 2 hours and 30 minutes after addition of the aqueous raw material liquid (II) at 50 ° C. to obtain a slurry raw material preparation liquid.
The obtained raw material mixture was supplied to a centrifugal spray dryer and dried to obtain a microspherical catalyst precursor. The dryer inlet temperature was 210 ° C. and the outlet temperature was 120 ° C.
200 g of the obtained catalyst precursor was filled in a SUS firing tube having a diameter of 3 inches, and the composite oxide was calcined at 680 ° C. for 2 hours while rotating the tube under a nitrogen gas flow of 5.0 NL / min. A catalyst was obtained.

(Preparation of tungsten trioxide)
A 50% by mass ammonium metatungstate aqueous solution was prepared from ammonium metatungstate [(NH ₄ ) ₆ H ₂ W ₁₂ O ₄₀ ], supplied to a centrifugal spray dryer, dried, and formed into microspheres. The dryer inlet temperature was 210 ° C. and the outlet temperature was 120 ° C.
The microspherical ammonium metatungstate (200 g) is placed on an evaporating dish, and is baked at 200 ° C. for 1 hour and further at 500 ° C. for 2 hours in a stationary baking furnace. Got. Next, the obtained tungsten trioxide was sieved to a predetermined particle size.
In addition, all the tungsten trioxides in the following examples and comparative examples were prepared by the same method as described above.

(Propane ammoxidation reaction)
A glass fluidized bed reactor having an inner diameter of 1B was charged with a mixture of 40 g of the composite oxide catalyst obtained above and 1.0 g of tungsten trioxide having an average particle diameter of 100 μm, and the reaction temperature was 440 ° C. and the reaction pressure was normal. Under pressure, a mixed gas having a molar ratio of propane: ammonia: oxygen: helium = 1: 1: 3: 18 was supplied at a contact time of 2.9 (sec · g / cc), and an ammoxidation reaction was carried out for 10 days.
The reaction results on the 10th day are shown in Table 1.

[Comparative Example 1]
(Preparation of composite oxide catalyst)
The composite oxide catalyst was prepared in the same manner as in Example 1.

(Propane ammoxidation reaction)
A glass fluidized bed reactor having an inner diameter of 1B is charged with 40 g of the composite oxide catalyst obtained above, and propane: ammonia: oxygen: helium = 1: 1: 3: under a reaction temperature of 440 ° C. and a normal pressure of the reaction. A mixed gas having a molar ratio of 18 was supplied at a contact time of 2.9 (sec · g / cc), and an ammoxidation reaction was carried out for 10 days.
The reaction results on the 10th day are shown in Table 1.

[Example 2]
(Preparation of composite oxide catalyst)
Mixing composition formula was produced by the composite oxide catalyst represented by _{Mo 1 V 0.21 Nb 0.10 Sb 0.22} W 0.05 O n /50.0wt%-SiO 2 as follows.
To 1738 g of water, 404.1 g of ammonium heptamolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O], 55.9 g of ammonium metavanadate [NH ₄ VO ₃ ], and antimony trioxide [Sb ₂ O ₃ ] was added and heated at 95 ° C. for 1 hour with stirring to obtain an aqueous raw material liquid (I).
Add 66.3g of hydrogen peroxide containing 30wt% as H ₂ O _{2 to} 397.4g of niobium mixed liquid (B ₀ ), and stir and mix at room temperature for 10 minutes to prepare aqueous raw material liquid (II) did.
After cooling the obtained aqueous raw material liquid (I) to 70 ° C., 735.7 g of silica sol containing 34.0 wt% as SiO ₂ was added, and hydrogen peroxide solution 129 containing 30 wt% as H ₂ O ₂ was further added. .3 g was added and stirring was continued at 55 ° C. for 30 minutes. Next, an aqueous raw material liquid (II), 52.5 g of a 50 wt% ammonium metatungstate aqueous solution as WO ₃ and a dispersion obtained by dispersing 250 g of powdered silica in 3375 g of water were sequentially added to obtain an aqueous mixed liquid (III). Obtained. The aqueous mixture (III) was 2 hours 30 minutes after addition of the aqueous raw material liquid (II) at 50 ° C.
The slurry was aged to obtain a slurry-like raw material mixture.
The obtained raw material mixture was supplied to a centrifugal spray dryer and dried to obtain a microspherical catalyst precursor. The dryer inlet temperature was 210 ° C. and the outlet temperature was 120 ° C.
200 g of the obtained catalyst precursor was filled in a SUS firing tube having a diameter of 3 inches, and the composite oxide was calcined at 680 ° C. for 2 hours while rotating the tube under a nitrogen gas flow of 5.0 NL / min. A catalyst was obtained.

(Propane ammoxidation reaction)
A glass fluidized bed reactor having an inner diameter of 1B is charged with 40 g of the composite oxide catalyst obtained above, and propane: ammonia: oxygen: helium = 1: 1: 3: under a reaction temperature of 440 ° C. and a normal pressure of the reaction. A mixed gas having a molar ratio of 18 was supplied at a contact time of 2.9 (sec · g / cc) to carry out an ammoxidation reaction. Immediately after the start of the reaction, tungsten trioxide having an average particle size of 100 μm was continuously added to the catalyst concentrated layer in the reactor in an amount of 0.2 g / day via a valve for 5 days, and the reaction was carried out for 10 days.
The reaction results on the 10th day are shown in Table 1.

[Example 3]
(Preparation of composite oxide catalyst)
A composite oxide catalyst having a composition formula of Mo ₁ V _0.21 Nb _0.10 Sb _0.22 W _0.04 O _n /50.0 wt% -SiO ₂ was produced as follows.
To 1757 g of water, 408.4 g of ammonium heptamolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O], 56.5 g of ammonium metavanadate [NH ₄ VO ₃ ], and antimony trioxide [Sb ₂ O ₃ ] was added and heated at 95 ° C. for 1 hour with stirring to obtain an aqueous raw material liquid (I).
Aqueous raw material liquid (II) is prepared by adding 66.3 g of hydrogen peroxide containing 30 wt% as H ₂ O _{2 to} 401.6 g of niobium mixed liquid (B ₀ ), and stirring and mixing at room temperature for 10 minutes. did.
After cooling the obtained aqueous raw material liquid (I) to 70 ° C., 735.7 g of silica sol containing 34.0 wt% as SiO ₂ was added, and hydrogen peroxide solution 129 containing 30 wt% as H ₂ O ₂ was further added. .3 g was added and stirring was continued at 55 ° C. for 30 minutes. Next, an aqueous raw material liquid (II), 42.4 g of a 50 wt% ammonium metatungstate aqueous solution as WO ₃ and a dispersion in which 250 g of powdered silica is dispersed in 3375 g of water are sequentially added to obtain an aqueous mixed liquid (III). Obtained. The aqueous mixed liquid (III) was aged 2 hours and 30 minutes after addition of the aqueous raw material liquid (II) at 50 ° C. to obtain a slurry raw material preparation liquid.
The obtained raw material mixture was supplied to a centrifugal spray dryer and dried to obtain a microspherical catalyst precursor. The dryer inlet temperature was 210 ° C. and the outlet temperature was 120 ° C.
200 g of the obtained catalyst precursor was filled in a SUS firing tube having a diameter of 3 inches, and the composite oxide was calcined at 680 ° C. for 2 hours while rotating the tube under a nitrogen gas flow of 5.0 NL / min. A catalyst was obtained.

(Propane ammoxidation reaction)
A glass fluidized bed reactor having an inner diameter of 1B is charged with 40 g of the composite oxide catalyst obtained above, and propane: ammonia: oxygen: helium = 1: 1: 3: under a reaction temperature of 440 ° C. and a normal pressure of the reaction. A mixed gas having a molar ratio of 18 was supplied at a contact time of 2.9 (sec · g / cc) to carry out an ammoxidation reaction. On the 3rd and 6th day from the start of the reaction, 0.5 g of tungsten trioxide having an average particle size of 50 μm was added at a time and reacted for 10 days.
The reaction results on the 10th day are shown in Table 1.

[Example 4]
(Preparation of composite oxide catalyst)
A composite oxide having a composition formula of Mo ₁ V _0.21 Nb _0.10 Sb _0.22 W _0.03 O _n /50.0 wt% -SiO ₂ was produced as follows.
To 1776 g of water, 412.8 g of ammonium heptamolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O], 57.1 g of ammonium metavanadate [NH ₄ VO ₃ ], and antimony trioxide [Sb ₂ O ₃ ] was added and heated at 95 ° C. for 1 hour with stirring to obtain an aqueous raw material liquid (I).
66.3 g of hydrogen peroxide containing 30 wt% as H ₂ O ₂ is added to 405.9 g of niobium mixed liquid (B ₀ ), and stirred and mixed at room temperature for 10 minutes to prepare an aqueous raw material liquid (II) did.
After cooling the obtained aqueous raw material liquid (I) to 70 ° C., 735.7 g of silica sol containing 34.0 wt% as SiO ₂ was added, and hydrogen peroxide solution 129 containing 30 wt% as H ₂ O ₂ was further added. .3 g was added and stirring was continued at 55 ° C. for 30 minutes. Next, an aqueous raw material liquid (II), 32.2 g of a 50 wt% ammonium metatungstate aqueous solution as WO ₃ and a dispersion obtained by dispersing 250 g of powdered silica in 3375 g of water were sequentially added to obtain an aqueous mixed liquid (III). Obtained. The aqueous mixed liquid (III) was aged 2 hours and 30 minutes after addition of the aqueous raw material liquid (II) at 50 ° C. to obtain a slurry raw material preparation liquid.
The obtained raw material mixture was supplied to a centrifugal spray dryer and dried to obtain a microspherical catalyst precursor. The dryer inlet temperature was 210 ° C. and the outlet temperature was 120 ° C.
200 g of the obtained catalyst precursor was filled in a SUS firing tube having a diameter of 3 inches, and the composite oxide was calcined at 680 ° C. for 2 hours while rotating the tube under a nitrogen gas flow of 5.0 NL / min. A catalyst was obtained.

(Propane ammoxidation reaction)
A glass fluidized bed reactor having an inner diameter of 1B is charged with 40 g of the composite oxide catalyst obtained above, and propane: ammonia: oxygen: helium = 1: 1: 3: under a reaction temperature of 440 ° C. and a normal pressure of the reaction. A mixed gas having a molar ratio of 18 was supplied at a contact time of 2.9 (sec · g / cc) to carry out an ammoxidation reaction. On the 3rd and 6th days from the start of the reaction, 0.5 g of tungsten trioxide having an average particle size of 130 μm was added, and the reaction was carried out for 10 days.
The reaction results on the 10th day are shown in Table 1.

[Comparative Example 2]
(Preparation of composite oxide catalyst)
The composite oxide catalyst was prepared in the same manner as in Example 2.

(Propane ammoxidation reaction)
A glass fluidized bed reactor having an inner diameter of 1B is charged with 40 g of the composite oxide catalyst obtained above, and propane: ammonia: oxygen: helium = 1: 1: 3: under a reaction temperature of 440 ° C. and a normal pressure of the reaction. A mixed gas having a molar ratio of 18 was supplied at a contact time of 2.9 (sec · g / cc) to carry out an ammoxidation reaction. On the 3rd and 6th day from the start of the reaction, 0.5 g of tungsten trioxide having an average particle diameter of less than 1 μm was added, and the reaction was carried out for 10 days.
The reaction results on the 10th day are shown in Table 1.

[Comparative Example 3]
(Preparation of composite oxide catalyst)
The composite oxide catalyst was prepared in the same manner as in Example 2.

(Propane ammoxidation reaction)
A glass fluidized bed reactor having an inner diameter of 1B is charged with 40 g of the composite oxide catalyst obtained above, and propane: ammonia: oxygen: helium = 1: 1: 3: under a reaction temperature of 440 ° C. and a normal pressure of the reaction. A mixed gas having a molar ratio of 18 was supplied at a contact time of 2.9 (sec · g / cc) to carry out an ammoxidation reaction. On the 3rd and 6th day from the start of the reaction, 0.5 g of tungsten trioxide having an average particle size of 600 μm or more was added, and the reaction was carried out for 10 days.
The reaction results on the 10th day are shown in Table 1.

[Example 5]
(Preparation of composite oxide catalyst)
The composite oxide catalyst was prepared in the same manner as in Example 2.

(Preparation of ammonium metatungstate)
Commercially available ammonium metatungstate [(NH ₄ ) ₁₀ H ₂ W ₁₂ O ₄ ] was sieved to a predetermined particle size.

(Propane ammoxidation reaction)
A glass fluidized bed reactor having an inner diameter of 1B is charged with 40 g of the composite oxide catalyst obtained above, and propane: ammonia: oxygen: helium = 1: 1: 3: under a reaction temperature of 440 ° C. and a normal pressure of the reaction. A mixed gas having a molar ratio of 18 was supplied at a contact time of 2.9 (sec · g / cc) to carry out an ammoxidation reaction. On the 3rd and 6th day from the start of the reaction, 0.5 g of ammonium metatungstate having an average particle diameter of 100 μm was added and reacted for 10 days.
The reaction results on the 10th day are shown in Table 1.

[Example 6]
(Preparation of composite oxide catalyst)
Mixing composition formula was produced by the composite oxide catalyst represented by _{Mo 1 V 0.22 Nb 0.11 Te 0.2} O n as follows.
To 3806 g of water, 832.1 g of ammonium heptamolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O], 120.5 g of ammonium metavanadate [NH ₄ VO ₃ ], and telluric acid [H ₆ TeO ₆ ] Was heated to 60 ° C. with stirring and dissolved, and then cooled to 30 ° C. to obtain an aqueous raw material liquid (I).
Add 66.3g of hydrogen peroxide containing 30wt% as H ₂ O _{2 to} 900.0g of niobium mixed liquid (B ₀ ), and stir and mix at room temperature for 10 minutes to prepare aqueous raw material liquid (II) did.
The obtained aqueous raw material liquid (I) was sprayed onto a Teflon (registered trademark) coated iron plate heated to 140 ° C. to obtain a microspherical catalyst precursor.
200 g of the obtained catalyst precursor was filled in a SUS firing tube having a diameter of 3 inches, and the composite oxide was calcined at 680 ° C. for 2 hours while rotating the tube under a nitrogen gas flow of 5.0 NL / min. A catalyst was obtained.

(Propane ammoxidation reaction)
A glass fluidized bed reactor having an inner diameter of 1B is charged with 40 g of the composite oxide catalyst obtained above, and propane: ammonia: oxygen: helium = 1: 1: 3: under a reaction temperature of 440 ° C. and a normal pressure of the reaction. A mixed gas having a molar ratio of 18 was supplied at a contact time of 2.9 (sec · g / cc) to carry out an ammoxidation reaction. On the 3rd and 6th days from the start of the reaction, 0.5 g of tungsten trioxide having an average particle size of 100 μm was added at a time and reacted for 10 days.
The reaction results on the 10th day are shown in Table 1.

[Comparative Example 4]
(Preparation of composite oxide catalyst)
A composite oxide catalyst was prepared in the same manner as in Example 6.

(Propane ammoxidation reaction)
40 g of the composite oxide catalyst obtained by adjusting to a glass fluidized bed reactor having an inner diameter of 1B was charged, and propane: ammonia: oxygen: helium = 1: 1: 3: 18 at a reaction temperature of 440 ° C. and a normal pressure of the reaction. A gas mixture having a molar ratio of 2.9 was supplied at a contact time of 2.9 (sec · g / cc), and an ammoxidation reaction was carried out for 10 days.
The reaction results on the 10th day are shown in Table 1.

[Example 7]
(Preparation of composite oxide catalyst)
A composite oxide catalyst having a composition formula of Mo ₁ V _0.20 Nb _0.10 Sb _0.23 W _0.03 O _n /50.0 wt% -SiO ₂ was produced as follows.
To 1685 g of water, 411.8 g of ammonium heptamolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O], 54.2 g of ammonium metavanadate [NH ₄ VO ₃ ], and antimony trioxide [Sb ₂ O ₃ ] was added and heated at 95 ° C. for 1 hour with stirring to obtain an aqueous raw material liquid (I).
Aqueous raw material liquid (II) is prepared by adding 66.3 g of hydrogen peroxide containing 30 wt% as H ₂ O _{2 to} 404.9 g of niobium mixed liquid (B ₀ ) and stirring and mixing at room temperature for 10 minutes. did.
After cooling the obtained aqueous raw material liquid (I) to 70 ° C., 735.7 g of silica sol containing 34.0 wt% as SiO ₂ was added, and hydrogen peroxide solution 129 containing 30 wt% as H ₂ O ₂ was further added. .3 g was added and stirring was continued at 55 ° C. for 30 minutes. Next, aqueous raw material liquid (II), 32.1 g of a 50 wt% ammonium metatungstate aqueous solution as WO ₃ and a dispersion liquid in which 250 g of powdered silica are dispersed in 3375 g of water are sequentially added to obtain an aqueous mixed liquid (III). Obtained. The aqueous mixture (III) was 2 hours 30 minutes after addition of the aqueous raw material liquid (II) at 50 ° C.
The slurry was aged to obtain a slurry-like raw material mixture.
The obtained raw material mixture was supplied to a centrifugal spray dryer and dried to obtain a microspherical catalyst precursor. The dryer inlet temperature was 210 ° C. and the outlet temperature was 120 ° C.
200 g of the obtained catalyst precursor was filled in a SUS firing tube having a diameter of 3 inches, and the composite oxide was calcined at 680 ° C. for 2 hours while rotating the tube under a nitrogen gas flow of 5.0 NL / min. A catalyst was obtained.

(Propane ammoxidation reaction)
A glass fluidized bed reactor having an inner diameter of 1B is charged with 40 g of the composite oxide catalyst obtained above, and propane: ammonia: oxygen: helium = 1: 1: 3: under a reaction temperature of 440 ° C. and a normal pressure of the reaction. A mixed gas having a molar ratio of 18 was supplied at a contact time of 2.9 (sec · g / cc) to carry out an ammoxidation reaction. On the 3rd and 6th days from the start of the reaction, 0.5 g of tungsten trioxide having an average particle size of 100 μm was added at a time and reacted for 10 days.
The reaction results on the 10th day are shown in Table 1.

[Comparative Example 5]
(Preparation of composite oxide catalyst)
A composite oxide catalyst was prepared in the same manner as in Example 7.

(Propane ammoxidation reaction)
A glass fluidized bed reactor having an inner diameter of 1B was charged with 40 g of the composite oxide catalyst obtained above, and propane: ammonia: oxygen: helium = 1: 1: 3: 18 at a reaction temperature of 440 ° C. and a normal pressure of the reaction. A gas mixture having a molar ratio of 2.9 was supplied at a contact time of 2.9 (sec · g / cc), and an ammoxidation reaction was carried out for 10 days.
The reaction results on the 10th day are shown in Table 1.

[Example 8]
(Preparation of composite oxide catalyst)
A composite oxide catalyst having a composition formula of Mo ₁ V _0.23 Nb _0.10 Sb _0.20 W _0.04 O _n /50.0 wt% -SiO ₂ was produced as follows.
In 1939 g of water, 410.5 g of ammonium heptamolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O], 62.1 g of ammonium metavanadate [NH ₄ VO ₃ ], and antimony trioxide [Sb ₂ O ₃ ] was added and heated at 95 ° C. for 1 hour with stirring to obtain an aqueous raw material liquid (I).
Aqueous raw material liquid (II) is prepared by adding 66.3 g of hydrogen peroxide containing 30 wt% as H ₂ O _{2 to} 403.6 g of niobium mixed liquid (B ₀ ), and stirring and mixing at room temperature for 10 minutes. did.
After cooling the obtained aqueous raw material liquid (I) to 70 ° C., 735.7 g of silica sol containing 34.0 wt% as SiO ₂ was added, and hydrogen peroxide solution 129 containing 30 wt% as H ₂ O ₂ was further added. .3 g was added and stirring was continued at 55 ° C. for 30 minutes. Next, an aqueous raw material liquid (II), a dispersion liquid in which 42.7 g of a 50 wt% ammonium metatungstate aqueous solution as WO _{3 and} 250 g of powdered silica are dispersed in 3375 g of water are sequentially added to obtain an aqueous mixed liquid (III). Obtained. The aqueous mixed liquid (III) was aged 2 hours and 30 minutes after addition of the aqueous raw material liquid (II) at 50 ° C. to obtain a slurry raw material preparation liquid.
The obtained raw material mixture was supplied to a centrifugal spray dryer and dried to obtain a microspherical catalyst precursor. The dryer inlet temperature was 210 ° C. and the outlet temperature was 120 ° C.
200 g of the obtained catalyst precursor was filled in a SUS firing tube having a diameter of 3 inches, and the composite oxide was calcined at 680 ° C. for 2 hours while rotating the tube under a nitrogen gas flow of 5.0 NL / min. A catalyst was obtained.

(Propane ammoxidation reaction)
A glass fluidized bed reactor having an inner diameter of 1B is charged with 40 g of the composite oxide catalyst obtained above, and propane: ammonia: oxygen: helium = 1: 1: 3: under a reaction temperature of 440 ° C. and a normal pressure of the reaction. A mixed gas having a molar ratio of 18 was supplied at a contact time of 2.9 (sec · g / cc) to carry out an ammoxidation reaction. On the 3rd and 6th days from the start of the reaction, 0.5 g of tungsten trioxide having an average particle size of 100 μm was added at a time and reacted for 10 days.
The reaction results on the 10th day are shown in Table 1.

[Comparative Example 6]
(Preparation of composite oxide catalyst)
The composite oxide catalyst was prepared in the same manner as in Example 8.

(Propane ammoxidation reaction)
A glass fluidized bed reactor having an inner diameter of 1B was charged with 40 g of the composite oxide catalyst obtained above, and propane: ammonia: oxygen: helium = 1: 1: 3: 18 at a reaction temperature of 440 ° C. and a normal pressure of the reaction. A gas mixture having a molar ratio of 2.9 was supplied at a contact time of 2.9 (sec · g / cc), and an ammoxidation reaction was carried out for 10 days.
The reaction results on the 10th day are shown in Table 1.

[Example 9]
(Preparation of composite oxide catalyst)
A composite oxide catalyst having a composition formula of Mo ₁ V _0.21 Nb _0.10 Sb _0.22 W _0.05 La _0.005 O _n /50.0 wt% -SiO ₂ was produced as follows.
In 1731 g of water, 402.6 g of ammonium heptamolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O], 55.7 g of ammonium metavanadate [NH ₄ VO ₃ ], and antimony trioxide [Sb ₂ O _3] ] And 5.0 g of lanthanum nitrate La (NO ₃ ) ₃ .6H ₂ O were added and heated at 95 ° C. for 1 hour with stirring to obtain an aqueous raw material liquid (I).
Aqueous raw material liquid (II) is prepared by adding 66.3 g of hydrogen peroxide containing 30 wt% as H ₂ O _{2 to} 402.9 g of niobium mixed liquid (B ₀ ) and stirring and mixing at room temperature for 10 minutes. did.
After cooling the obtained aqueous raw material liquid (I) to 70 ° C., 735.7 g of silica sol containing 34.0 wt% as SiO ₂ was added, and hydrogen peroxide solution 129 containing 30 wt% as H ₂ O ₂ was further added. .3 g was added and stirring was continued at 55 ° C. for 30 minutes. Next, an aqueous raw material liquid (II), a dispersion obtained by dispersing 52.3 g of a 50 wt% ammonium metatungstate aqueous solution as WO _{3 and} 250 g of powdered silica in 3375 g of water are sequentially added to obtain an aqueous mixed liquid (III). Obtained. The aqueous mixed liquid (III) was aged 2 hours and 30 minutes after addition of the aqueous raw material liquid (II) at 50 ° C. to obtain a slurry raw material preparation liquid.
The obtained raw material mixture was supplied to a centrifugal spray dryer and dried to obtain a microspherical catalyst precursor. The dryer inlet temperature was 210 ° C. and the outlet temperature was 120 ° C.
200 g of the obtained catalyst precursor was filled in a SUS firing tube having a diameter of 3 inches, and the composite oxide was calcined at 680 ° C. for 2 hours while rotating the tube under a nitrogen gas flow of 5.0 NL / min. A catalyst was obtained.

(Propane ammoxidation reaction)
A glass fluidized bed reactor having an inner diameter of 1B is charged with 40 g of the composite oxide catalyst obtained above, and propane: ammonia: oxygen: helium = 1: 1: 3: under a reaction temperature of 440 ° C. and a normal pressure of the reaction. A mixed gas having a molar ratio of 18 was supplied at a contact time of 2.9 (sec · g / cc) to carry out an ammoxidation reaction. On the 3rd and 6th days from the start of the reaction, 0.5 g of tungsten trioxide having an average particle size of 100 μm was added at a time and reacted for 10 days.
The reaction results on the 10th day are shown in Table 1.

[Comparative Example 7]
(Preparation of composite oxide catalyst)
A composite oxide catalyst was prepared in the same manner as in Example 9.

(Propane ammoxidation reaction)
A glass fluidized bed reactor having an inner diameter of 1B was charged with 40 g of the composite oxide catalyst obtained above, and propane: ammonia: oxygen: helium = 1: 1: 3: 18 at a reaction temperature of 440 ° C. and a normal pressure of the reaction. A gas mixture having a molar ratio of 2.9 was supplied at a contact time of 2.9 (sec · g / cc), and an ammoxidation reaction was carried out for 10 days.
The reaction results on the 10th day are shown in Table 1.

[Example 10]
(Preparation of composite oxide catalyst)
Mixing composition formula was produced by the composite oxide catalyst represented by _{Mo 1 V 0.2 Nb 0.12 Sb 0.2} W 0.03 Ce 0.005 O n /25.0wt%-SiO 2 as follows.
In 2563 g of water, 620.2 g of ammonium heptamolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O], 81.7 g of ammonium metavanadate [NH ₄ VO ₃ ], antimony trioxide [Sb ₂ O ₃ 102.2 g and 7.7 g of cerium nitrate Ce (NO ₃ ) ₃ .6H ₂ O were added and heated at 95 ° C. for 1 hour with stirring to obtain an aqueous raw material liquid (I).
Add 66.3g of hydrogen peroxide containing 30wt% as H ₂ O _{2 to} 731.8g of niobium mixed liquid (B ₀ ) and stir and mix at room temperature for 10 minutes to prepare aqueous raw material liquid (II) did.
After cooling the obtained aqueous raw material liquid (I) to 70 ° C., 367.9 g of silica sol containing 34.0 wt% as SiO ₂ was added, and hydrogen peroxide solution 129 containing 30 wt% as H ₂ O ₂ was further added. .3 g was added and stirring was continued at 55 ° C. for 30 minutes. Next, an aqueous raw material liquid (II), a dispersion in which 48.3 g of a 50 wt% ammonium metatungstate aqueous solution as WO _{3 and} 125 g of powdered silica are dispersed in 1688 g of water are sequentially added to obtain an aqueous mixed liquid (III). Obtained. The aqueous mixed liquid (III) was aged 2 hours and 30 minutes after addition of the aqueous raw material liquid (II) at 50 ° C. to obtain a slurry raw material preparation liquid.
The obtained raw material mixture was supplied to a centrifugal spray dryer and dried to obtain a microspherical catalyst precursor. The dryer inlet temperature was 210 ° C. and the outlet temperature was 120 ° C.
200 g of the obtained catalyst precursor was filled in a SUS firing tube having a diameter of 3 inches, and the composite oxide was calcined at 680 ° C. for 2 hours while rotating the tube under a nitrogen gas flow of 5.0 NL / min. A catalyst was obtained.

(Propane ammoxidation reaction)
A glass fluidized bed reactor having an inner diameter of 1B is charged with 40 g of the composite oxide catalyst obtained above, and propane: ammonia: oxygen: helium = 1: 1: 3: under a reaction temperature of 440 ° C. and a normal pressure of the reaction. A mixed gas having a molar ratio of 18 was supplied at a contact time of 2.9 (sec · g / cc) to carry out an ammoxidation reaction. On the 3rd and 6th days from the start of the reaction, 0.5 g of tungsten trioxide having an average particle size of 100 μm was added at a time and reacted for 10 days.
The reaction results on the 10th day are shown in Table 1.

[Comparative Example 8]
(Preparation of composite oxide catalyst)
A composite oxide catalyst was prepared in the same manner as in Example 10.

(Propane ammoxidation reaction)
A glass fluidized bed reactor having an inner diameter of 1B was charged with 40 g of the composite oxide catalyst obtained above, and propane: ammonia: oxygen: helium = 1: 1: 3: 18 at a reaction temperature of 440 ° C. and a normal pressure of the reaction. A gas mixture having a molar ratio of 2.9 was supplied at a contact time of 2.9 (sec · g / cc), and an ammoxidation reaction was carried out for 10 days.
The reaction results on the 10th day are shown in Table 1.

[Example 11]
(Preparation of composite oxide catalyst)
A composite oxide catalyst having a charging composition formula of Mo ₁ V _0.2 Nb _0.10 Sb _0.2 W _0.04 O _n /65.0 wt% -SiO ₂ was produced as follows.
In 1176 g of water, 291.0 g of ammonium heptamolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O], 38.3 g of ammonium metavanadate [NH ₄ VO ₃ ], antimony trioxide [Sb ₂ O ₃ And was heated at 95 ° C. for 1 hour with stirring to obtain an aqueous raw material liquid (I).
Aqueous raw material liquid (II) is prepared by adding 66.3 g of hydrogen peroxide containing 30 wt% as H ₂ O _{2 to} 286.1 g of niobium mixed liquid (B ₀ ) and stirring and mixing at room temperature for 10 minutes. did.
After cooling the obtained aqueous raw material liquid (I) to 70 ° C., 956.4 g of silica sol containing 34.0 wt% as SiO ₂ was added, and hydrogen peroxide solution 129 containing 30 wt% as H ₂ O ₂ was further added. .3 g was added and stirring was continued at 55 ° C. for 30 minutes. Next, an aqueous raw material liquid (II), 30.2 g of a 50 wt% ammonium metatungstate aqueous solution as WO ₃ and a dispersion obtained by dispersing 325 g of powdered silica in 4388 g of water were sequentially added to obtain an aqueous mixed liquid (III). Obtained. The aqueous mixed liquid (III) was aged 2 hours and 30 minutes after addition of the aqueous raw material liquid (II) at 50 ° C. to obtain a slurry raw material preparation liquid.
The obtained raw material mixture was supplied to a centrifugal spray dryer and dried to obtain a microspherical catalyst precursor. The dryer inlet temperature was 210 ° C. and the outlet temperature was 120 ° C.
200 g of the obtained catalyst precursor was filled in a SUS firing tube having a diameter of 3 inches, and the composite oxide was calcined at 680 ° C. for 2 hours while rotating the tube under a nitrogen gas flow of 5.0 NL / min. A catalyst was obtained.

(Propane ammoxidation reaction)
A glass fluidized bed reactor having an inner diameter of 1B is charged with 40 g of the composite oxide catalyst obtained above, and propane: ammonia: oxygen: helium = 1: 1: 3: under a reaction temperature of 440 ° C. and a normal pressure of the reaction. A mixed gas having a molar ratio of 18 was supplied at a contact time of 2.9 (sec · g / cc) to carry out an ammoxidation reaction. On the 3rd and 6th day from the start of the reaction, 0.5 g of tungsten trioxide having an average particle diameter of 100 μm was added and reacted for 10 days.
The reaction results on the 10th day are shown in Table 1.

[Comparative Example 9]
(Preparation of composite oxide catalyst)
A composite oxide catalyst was prepared in the same manner as in Example 11.

(Propane ammoxidation reaction)
A glass fluidized bed reactor having an inner diameter of 1B was charged with 40 g of the composite oxide catalyst obtained above, and propane: ammonia: oxygen: helium = 1: 1: 3: 18 at a reaction temperature of 440 ° C. and a normal pressure of the reaction. A gas mixture having a molar ratio of 2.9 was supplied at a contact time of 2.9 (sec · g / cc), and an ammoxidation reaction was carried out for 10 days.
The reaction results on the 10th day are shown in Table 1.

[Example 12]
(Preparation of composite oxide catalyst)
Mixing composition formula was produced by the composite oxide catalyst represented by _{Mo 1 V 0.22 Nb 0.11 Sb 0.2} O n /50.0wt%-SiO 2 as follows.
In 1933 g of water, 428.0 g of ammonium heptamolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O], 62.0 g of ammonium metavanadate [NH ₄ VO ₃ ], antimony trioxide [Sb ₂ O ₃ And was heated at 95 ° C. for 1 hour with stirring to obtain an aqueous raw material liquid (I).
66.3 g of hydrogen peroxide containing 30 wt% as H ₂ O ₂ was added to 462.9 g of the niobium mixed solution (B ₀ ), and the mixture was stirred and mixed at room temperature for 10 minutes to prepare an aqueous raw material liquid (II) did.
After cooling the obtained aqueous raw material liquid (I) to 70 ° C., 735.7 g of silica sol containing 34.0 wt% as SiO ₂ was added, and hydrogen peroxide solution 129 containing 30 wt% as H ₂ O ₂ was further added. .3 g was added and stirring was continued at 55 ° C. for 30 minutes. Next, an aqueous raw material liquid (II) and a dispersion obtained by dispersing 250 g of powdered silica in 3375 g of water were sequentially added to obtain an aqueous mixed liquid (III). The aqueous mixed liquid (III) was aged 2 hours and 30 minutes after addition of the aqueous raw material liquid (II) at 50 ° C. to obtain a slurry raw material preparation liquid.
The obtained raw material mixture was supplied to a centrifugal spray dryer and dried to obtain a microspherical catalyst precursor. The dryer inlet temperature was 210 ° C. and the outlet temperature was 120 ° C.
200 g of the obtained catalyst precursor was filled in a SUS firing tube having a diameter of 3 inches, and the composite oxide was calcined at 680 ° C. for 2 hours while rotating the tube under a nitrogen gas flow of 5.0 NL / min. A catalyst was obtained.

(Propane ammoxidation reaction)
A glass fluidized bed reactor having an inner diameter of 1B is charged with 40 g of the composite oxide catalyst obtained above, and propane: ammonia: oxygen: helium = 1: 1: 3: under a reaction temperature of 440 ° C. and a normal pressure of the reaction. A mixed gas having a molar ratio of 18 was supplied at a contact time of 2.9 (sec · g / cc) to carry out an ammoxidation reaction. On the 3rd and 6th days from the start of the reaction, 0.5 g of tungsten trioxide having an average particle size of 100 μm was added at a time and reacted for 10 days.
The reaction results on the 10th day are shown in Table 1.

[Comparative Example 10]
(Preparation of composite oxide catalyst)
A composite oxide catalyst was prepared in the same manner as in Example 12.

(Propane ammoxidation reaction)
A glass fluidized bed reactor having an inner diameter of 1B was charged with 40 g of the composite oxide catalyst obtained above, and propane: ammonia: oxygen: helium = 1: 1: 3: 18 at a reaction temperature of 440 ° C. and a normal pressure of the reaction. A gas mixture having a molar ratio of 2.9 was supplied at a contact time of 2.9 (sec · g / cc), and an ammoxidation reaction was carried out for 10 days.
The reaction results on the 10th day are shown in Table 1.

[Example 13]
(Preparation of composite oxide catalyst and tungsten trioxide)
A composite oxide catalyst having a charging composition formula of Mo ₁ V _0.41 Nb _0.2 Sb _0.34 O _n /40.0 wt% -SiO ₂ was produced as follows.
To 3530 g of water, 414.5 g of ammonium heptamolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O], 111.9 g of ammonium metavanadate [NH ₄ VO ₃ ], antimony trioxide [Sb ₂ O ₃ And was heated at 95 ° C. for 1 hour with stirring to obtain an aqueous raw material liquid (I).
Aqueous raw material liquid (II) is prepared by adding 66.3 g of hydrogen peroxide containing 30 wt% as H ₂ O _{2 to} 815.2 g of niobium mixed liquid (B ₀ ) and stirring and mixing at room temperature for 10 minutes. did.
After cooling the obtained aqueous raw material liquid (I) to 70 ° C., 589 g of silica sol containing 34.0 wt% as SiO ₂ was added, and further 129.3 g of hydrogen peroxide containing 30 wt% as H ₂ O _2. Was added and stirring was continued at 55 ° C. for 30 minutes. Next, an aqueous raw material liquid (II) and a dispersion obtained by dispersing 200 g of powdered silica in 2700 g of water were sequentially added to obtain an aqueous mixed liquid (III). The aqueous mixed liquid (III) was aged 2 hours and 30 minutes after addition of the aqueous raw material liquid (II) at 50 ° C. to obtain a slurry raw material preparation liquid.
The obtained raw material mixture was supplied to a centrifugal spray dryer and dried to obtain a microspherical catalyst precursor. The dryer inlet temperature was 210 ° C. and the outlet temperature was 120 ° C.
200 g of the obtained catalyst precursor was filled in a SUS firing tube having a diameter of 3 inches, and the composite oxide was calcined at 680 ° C. for 2 hours while rotating the tube under a nitrogen gas flow of 5.0 NL / min. A catalyst was obtained.

(Propane oxidation reaction)
A glass fluidized bed reactor having an inner diameter of 1B is filled with 40 g of the composite oxide catalyst obtained above, and propane: oxygen: water vapor: helium = 1: 3: 14 under a reaction temperature of 400 ° C. and a normal pressure of reaction. A mixed gas having a molar ratio of 10 was supplied at a contact time of 1.2 (sec · g / cc) to carry out an oxidation reaction. Immediately after the start of the reaction, tungsten trioxide having an average particle diameter of 100 μm was continuously added to the catalyst concentrated layer in the reactor in an amount of 0.2 g / day via a valve for 5 days, and the reaction was carried out for 10 days.
The reaction results on the 10th day are shown in Table 2.

[Comparative Example 11]
(Preparation of composite oxide catalyst)
A composite oxide catalyst was prepared in the same manner as in Example 13.

(Propane oxidation reaction)
A glass fluidized bed reactor having an inner diameter of 1B is filled with 40 g of the composite oxide catalyst obtained above, and propane: oxygen: water vapor: helium = 1: 3: 14 under a reaction temperature of 400 ° C. and a normal pressure of reaction. A mixed gas having a molar ratio of 10 was supplied at a contact time of 1.2 (sec · g / cc) to carry out an oxidation reaction.
The reaction results on the 10th day are shown in Table 2.

Claims (3)

By subjecting propane or isobutane to a gas phase catalytic oxidation reaction or a gas phase catalytic ammoxidation reaction using a fluidized bed reactor in the presence of a complex oxide catalyst containing Mo, V and Nb, the corresponding unsaturated acid or non-oxidizing catalyst is obtained. A method for producing a saturated nitrile, comprising:
The step of contacting with said complex oxide catalyst tungsten compound having an average particle diameter 1~500μm in the fluidized bed reactor seen including,
The tungsten compound is an ammonium salt, carboxylate, nitrate, carboxylate ammonium salt, peroxocarboxylate salt, ammonium peroxocarboxylate salt, ammonium halide salt, halide, acetylacetonate, alkoxide, triphenylate, and A method for producing an unsaturated acid or an unsaturated nitrile, which is at least one selected from the group consisting of polyoxometalates and tungsten dioxide, tungstic acid, ammonium metatungstate, ammonium paratungstate and tungsten trioxide . The method for producing an unsaturated acid or unsaturated nitrile according to claim 1, wherein the composite oxide catalyst contains a composite oxide represented by the following composition formula (1).
_{Mo 1 V a Nb b A c} X d Z e O n (1)
(In Formula (1), Component A represents at least one element selected from Te and Sb, Component X represents at least one element selected from W, Bi, and Mn, and Component Z represents La, At least one element selected from Ce, Pr, Yb, Y, Sc, Sr, and Ba; a, b, c, d, e, and n represent atomic ratios of each element per Mo atom; Is 0.01 ≦ a ≦ 1, b is 0.01 ≦ b ≦ 1, c is 0.01 ≦ c ≦ 1, d is 0 ≦ d ≦ 1, e is 0 ≦ e ≦ 1, and n is a configuration (The number is determined by the valence of the element.) The composite oxide catalyst comprises a composite oxide with respect to the total catalyst is supported on 20 to 70% by weight of silica in terms of SiO _2, the unsaturated acid or unsaturated nitrile according to claim 1 or 2, wherein preparation Method.