JP2003048870A - Method for producing acrylonitrile and / or acrylic acid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas phase catalytic oxidation reaction of propane with ammonia and oxygen in the presence of a composite metal oxide catalyst containing molybdenum, vanadium, and tellurium using a fluidized bed reactor to react acrylonitrile and / or Alternatively, the present invention provides a method for producing acrylic acid stably at a high yield over a long period of time. SOLUTION: In a fluidized bed reactor, propane is subjected to a gas phase catalytic oxidation reaction with ammonia and oxygen in the presence of a composite metal oxide catalyst containing molybdenum, vanadium and tellurium to produce acrylonitrile and / or acrylic acid. At this time, a composite metal oxide containing molybdenum and tellurium is added as an activator to the reaction system.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing acrylonitrile and / or acrylic acid by subjecting propane to a gas phase catalytic oxidation reaction with ammonia and oxygen using a fluidized bed reactor. More specifically, it relates to a method for stably producing these by suppressing a decrease in reaction performance over time.

[0002]

Acrylonitrile is industrially important as an intermediate raw material for synthetic resins, synthetic fibers, synthetic rubbers, and acrylic acid is a raw material for synthetic resins, paints, adhesives, plasticizers and the like. These chemicals are currently manufactured by the vapor-phase catalytic oxidation reaction of propylene or the vapor-phase catalytic oxidation reaction (ammoxidation reaction) in which ammonia is present in the reaction system. There is growing interest in replacing propylene with propylene.
Since the oxidation reaction and the ammoxidation reaction are exothermic reactions, a fluidized bed reactor system is adopted in which the reaction heat can be easily removed and the temperature can be controlled over the entire catalyst layer. There are many reports on research on catalysts for propane vapor-phase catalytic oxidation reactions and ammoxidation reactions.
It is known that a composite metal oxide catalyst containing o), vanadium (V) and tellurium (Te) as essential components exhibits superior performance to other metal oxide catalysts. The inventor also
According to JP-A-2-257, JP-A-5-148212, JP-A-5-208136, etc., that a catalyst containing Mo, V, Te is effective for producing acrylonitrile by ammoxidation reaction of propane, Further, it is disclosed in JP-A-6-279351 that it is effective for the production of acrylic acid by the oxidation reaction of propane.

The performances of the composite metal oxide catalysts disclosed in these publications decrease with the progress of the gas phase catalytic oxidation reaction depending on the selection of reaction operating conditions, and the yield of acrylonitrile and / or acrylic acid decreases. It has been observed to do. Therefore, a method of activating a deteriorated catalyst by adding a substance having an activating effect has been proposed. For maintaining the performance of oxide catalysts containing molybdenum and tellurium, for example, in Japanese Patent Laid-Open No. 58-139745 and Japanese Patent Publication No. 41135/1984, an oxidation reaction, an ammoxidation reaction or a dehydrogenation reaction of an organic compound is described. Discloses a method of activating a catalyst having reduced performance by adding a tellurium compound or a tellurium compound and a molybdenum compound. However, these publications only disclose examples of methanol ammoxidation reaction, propylene ammoxidation reaction, toluene ammoxidation reaction, and butene oxidative dehydrogenation reaction.

Further, recently, in JP-A-11-124361, when acrylonitrile is produced by subjecting propane to a gas phase catalytic ammoxidation reaction in the presence of an oxide catalyst containing molybdenum, tellurium, vanadium and niobium, A method of adding a tellurium compound and optionally a molybdenum compound as an activator at the time of reaction has been proposed. It is reported that in this method, about 1% of the catalyst weight in the reactor is regularly added to carry out the reaction, and the reaction results are slightly improved immediately after the addition. However,
There is no description about the change with time in the reaction results after addition. Furthermore, the ratio of the added telluric acid incorporated into the catalyst is not described, and according to the research conducted by the present inventors, at least a part of the added telluric acid is reduced by tellurium oxide or a reaction gas. In response, the metal tellurium is produced, and these tellurium oxide and metal tellurium act on the material forming the reactor, the pipe connected to the reactor, etc., to close the pipe connected to the reactor. It may cause damage. Therefore, in the presence of an oxide catalyst containing molybdenum, tellurium, vanadium and niobium, when producing acrylonitrile by a gas phase catalytic ammoxidation reaction of propane, a tellurium compound and optionally a molybdenum compound are produced during the reaction. There was a problem in terms of practical use in the method of adding as an activator.

[0005]

DISCLOSURE OF THE INVENTION The present invention is a method of using a fluidized bed reactor to carry out a gas phase catalytic oxidation reaction of propane with ammonia and oxygen in the presence of a mixed metal oxide catalyst containing molybdenum, vanadium and tellurium. It is an object of the present invention to provide a method for stably producing acrylonitrile and / or acrylic acid in a high yield over a long period of time.

[0006]

The present inventors have used a fluidized bed reactor in the presence of a mixed metal oxide catalyst containing molybdenum, vanadium and tellurium by a gas phase catalytic oxidation reaction of propane to produce acrylonitrile and / or Further, as a result of intensive research on a method for producing acrylic acid, the present invention has been completed.

That is, the gist of the present invention is to use a fluidized bed reactor in the presence of a mixed metal oxide catalyst containing molybdenum, vanadium and tellurium to cause propane to undergo a gas phase catalytic oxidation reaction with ammonia and oxygen to obtain acrylonitrile and And / or acrylonitrile and / or acrylonitrile, which is characterized in that a complex metal oxide containing molybdenum and tellurium is added to the reaction system as an activator when producing acrylic acid.
Or it exists in the manufacturing method of acrylic acid.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
In the present invention, a fluidized bed reactor is used to produce acrylonitrile and / or acrylic acid by gas phase catalytic oxidation reaction of propane with ammonia and oxygen in the presence of a mixed metal oxide catalyst containing molybdenum, vanadium and tellurium. In doing so, a composite metal oxide containing molybdenum and tellurium is added to the reaction system as an activator.

In the present invention, a fluidized bed reactor is used.
This is because the gas-phase catalytic ammoxidation reaction of propane is an exothermic reaction, so that the reaction temperature can be easily controlled, and, as proposed in the present invention, a specific substance is selected while continuing the reaction to maintain the catalytic performance. It depends on what can be added. As the catalyst of the present invention, a mixed metal oxide catalyst containing molybdenum, vanadium and tellurium is used, and molybdenum, vanadium, X, Y and oxygen (X is tellurium or tellurium and antimony, Y is niobium, tantalum, tungsten, titanium). , Antimony, aluminum, zirconium, chromium, manganese, iron, ruthenium, cobalt, rhodium, nickel, palladium, platinum, bismuth, boron, indium, phosphorus, germanium, rare earth element, alkali metal, alkaline earth metal A mixed metal oxide catalyst containing one or more of the following elements).

Then, the abundance ratios of molybdenum (Mo), vanadium (V), X and Y in the mixed metal oxide catalyst are as follows: 0.25 <rMo <0.98 0.003 <rV <0. 5 0.003 <rX <0.5 0 ≦ rY <0.5 (where rMo, rV, rX and rY represent the mole fractions of Mo, V, X and Y with respect to the total of the above components excluding oxygen). More preferable is a mixed metal oxide catalyst that simultaneously satisfies

The substance added as an activator in the present invention is
It is a mixed metal oxide containing molybdenum and tellurium.
Molybdenum, vanadium, X, Y and oxygen (X is tellurium or tellurium and antimony, Y is niobium, tantalum, tungsten, titanium, antimony, aluminum, zirconium, chromium, manganese, iron, ruthenium, cobalt, rhodium, nickel, palladium, A composite metal oxide containing one or more elements selected from the group consisting of platinum, bismuth, boron, indium, phosphorus, germanium, rare earth elements, alkali metals and alkaline earth metals) is preferable.

Then, the abundance ratios of molybdenum (Mo), vanadium (V), X and Y in the composite metal oxide catalyst are determined as follows: 0.25 <rMo <0.98 0.003 <rV <0. 5 0.003 <rX <0.5 0 ≦ rY <0.5 (where rMo, rV, rX and rY represent the mole fractions of Mo, V, X and Y with respect to the total of the above components excluding oxygen). ) Is more preferable at the same time.

In the production process of the present invention, the addition of the activator is extremely important in achieving the effects of the present invention. Specifically, it is possible to easily activate the catalyst deteriorated by the gas-phase catalytic ammoxidation reaction by adding an activator. Therefore, the production of acrylonitrile and / or acrylic acid can be carried out for a long time while maintaining a high yield. It can be carried out stably over a period of time. It is presumed that the addition of the activator causes a reaction between the catalyst particles in the fluidized bed reactor and the added activator to recover the performance of the catalyst particles.

The mole fraction of molybdenum and / or tellurium in the composite metal oxide added as an activator to the reaction system is
It is preferable that the molar ratio of each element of molybdenum and / or tellurium in the composite metal oxide catalyst present in the reaction system at the time of addition is equal to or more than the above. As a preferred embodiment, for example, the mixed metal oxide catalyst and the mixed metal oxide having the same molar fraction of molybdenum and / or tellurium at the start of the reaction, the molar fraction of molybdenum and / or tellurium relative to the mixed metal oxide catalyst are Examples thereof include an enhanced complex metal oxide. These complex metal oxides have good affinity with the catalyst in the reaction system, and it is speculated that the active components are reconstituted and the performance is maintained during the gas phase catalytic oxidation reaction. It

The activator proposed in the present invention is a composite metal oxide containing molybdenum and tellurium, and does not include a molybdenum compound or a tellurium compound which is not a composite metal oxide. When the tellurium compound or the molybdenum compound is added in addition to the tellurium compound when the catalyst performance is lowered, it may be seen that the catalyst performance is temporarily improved 1 to 10 hours after the addition. This is presumed to be due to the loss of catalytic performance due to the loss of molybdenum and tellurium in the mixed metal oxide catalyst. The loss of these elements is confirmed by a fluorescent X-ray analysis method, an ICP-emission method, etc., but it is considered that the addition of the compounds of these lost elements temporarily compensates the loss and restores the catalytic performance. However, in this case, the catalyst performance is temporarily improved and then rapidly lowered, and it is difficult to maintain the performance for a long period of time.

Then, for example, when telluric acid, which is a typical activator, is added, part of it is also incorporated into the composite metal oxide catalyst, but the telluric acid that is not incorporated is reduced in a gas phase catalytic oxidation reaction atmosphere. It may be converted into metal tellurium and deposited on the pipe or the like connected to the reactor to block the pipe or the like. Further, since tellurium has a high affinity with metals such as iron and chromium, there is a possibility that these materials may be damaged when attached to the reactor or peripheral pipes. If the molybdenum compound is not incorporated into the catalyst, it may be accumulated in the pipe connected to the reactor, which may hinder stable operation. For this reason, the addition of molybdenum compounds and tellurium compounds that are not complex metal oxides is not preferable for stable operation.

In the present invention, an activator is added to the reaction system, and the reaction system means a fluidized bed reactor which is substantially in operation. Further, the addition means to supply an activator to the fluidized bed reactor, and when the activator itself has a gas phase catalytic oxidation reaction activity of propane, the fluidized bed reactor is used in order to maintain a suitable reaction rate. If necessary, a part of the catalyst may be extracted. The activator can be added continuously or intermittently, and at the same time as the addition, the particles can be continuously or intermittently withdrawn from the fluidized bed reactor.

The method of adding the activator to the reaction system is not particularly limited, but, for example, a method in which a pipe for adding the activator is combined with the reactor and is added separately from the pipe for supplying the raw material gas for the ammoxidation reaction. Is simple. According to this method, powder particles similar to the fluidized bed catalyst can be pressure-fed into the reactor together with air streams such as air and nitrogen through a pipe, and the catalyst and the activator can be well mixed and contacted. You can

The frequency of addition of the activator proposed in the present invention is not particularly limited as long as the effect of the present invention can be obtained, but normally the conversion rate of propane is 95% with respect to the conversion rate of propane 24 hours after the start of the reaction. Add after the following.
From a practical point of view, the addition of activator is 1 to 30 days.
Once, preferably once every 1 to 7 days. The amount of the activator to be added is not particularly limited, but when the activator is added in a large amount and rapidly, the activator itself has propane vapor-phase catalytic ammoxidation reaction activity, and the fluidized state of the fluidized bed catalyst changes. Reaction conditions greatly change, which is not preferable. The amount of the activator is usually 0.01 to 30% by weight, preferably 0.1 to 20% by weight, based on the composite oxide catalyst in the fluidized bed reactor. Further, in order to prevent the fluidized state of the fluidized bed from changing and to smoothly operate the fluidized bed reactor, the weight of particles (catalyst component and activator, etc.) in the fluidized bed reactor should be 90-90 relative to the start of the reaction. It is preferably maintained at 110%. The weight of particles in the fluidized bed reactor is determined by an ordinary method by measuring the pressure difference between the upper and lower sides of the fluidized bed.

In determining the addition conditions such as the frequency and amount of addition of the activator, for example, the activator is added little by little while measuring the results of the gas phase catalytic oxidation reaction, and the activator is most effective. Determine the frequency and amount of addition to work. The method for producing a composite metal oxide catalyst containing molybdenum, vanadium and tellurium used in the present invention, and a composite metal oxide containing molybdenum and tellurium that is an activator are not particularly limited, but water or a raw material of the composite oxide is used. Two methods are well known: a method of preparing from a solution or slurry of an organic solvent and a method of mixing raw materials of a composite oxide to prepare by a high temperature solid phase reaction. In order to obtain a catalyst having more excellent performance, the former method, in particular, a method of preparing an aqueous solution in the form of a solution or slurry containing each component, followed by drying and firing is preferable.
As raw materials for preparing the catalyst of the present invention, carboxylates, carboxylic acid ammonium salts, ammonium halide salts, oxides, hydrous oxides, oxyacids and salts thereof, halides, hydrogen acids, acetylacetonates, alkoxides. A compound such as a halide, or a metal can be solubilized or slurried with an appropriate reagent before use. There is no particular limitation on the method for preparing a solution or slurry containing a compound containing a catalyst-constituting element, but a method of sequentially adding a predetermined amount of a catalyst raw material to water while stirring the water is generally used, and as necessary. Set the temperature, the concentration of the solution or the slurry, and concentrate or age. In addition, 1 to 90% by weight of a known carrier component, such as silica, alumina, titania, zirconia, aluminosilicate, diatomaceous earth, etc., in the operation of preparing a solution or a slurry.
Add about. Such a carrier component may be added at the same time when preparing a solution of a catalyst raw material or a slurry,
Alternatively, it may be added after drying the solution or slurry.

The method for drying the obtained solution or slurry is not particularly limited, and depends on the amount and form of the catalyst to be produced,
A method of adding the above-mentioned solution or slurry to a vessel such as a continuous evaporation dish and evaporating to dryness on a heat source such as an electric heater, a method of evaporating a solvent in a hot air dryer, a spray drying method. Freeze drying method, vacuum drying method, etc. are adopted. Next, the obtained dried product is subjected to heat treatment, and the heat treatment method can be arbitrarily adopted depending on the property and scale of the dried product, but it is usually heat treatment on an evaporation dish, a rotary furnace, or a fluidized baking furnace. Etc. are heat-treated in a heating furnace. Moreover, you may combine these processes in multiple types. Although the firing conditions vary depending on the method used, the temperature is usually 200 to 700.
℃, preferably 250 ~ 650 ℃, the time is usually 5 minutes to 3
It is carried out for 0 hours, preferably for 1 to 10 hours. Further, the firing may be performed in an oxygen atmosphere, but a heat treatment in the absence of oxygen may be adopted, or a heat treatment in an oxygen atmosphere and a heat treatment in the absence of oxygen may be combined. It is possible. The heat treatment in the absence of oxygen is performed in an atmosphere of an inert gas such as nitrogen, argon or helium, or in vacuum.

According to the method proposed in the present invention, the production of acrylonitrile and / or acrylic acid can be advantageously carried out by the gas phase catalytic oxidation reaction of propane.
The reaction temperature is usually 2 as the conditions for the gas phase catalytic oxidation reaction.
0 to 500 ° C, preferably 300 to 490 ° C,
The gas space velocity SV in the gas phase reaction is usually 100 to 1
It is 0000 hr ^-1 , preferably 300 to 6000 hr ^-1 . The gas-phase catalytic oxidation reaction is usually carried out under atmospheric pressure, but may be carried out under low pressure or low pressure. In addition, as a diluent gas for adjusting the space velocity and the oxygen partial pressure, nitrogen,
An inert gas such as argon, helium or carbon dioxide can be used. Further, in order to increase the selectivity to the target product, the reaction is carried out with the conversion rate of hydrocarbons kept at about 70% or less, and unreacted hydrocarbons are separated and recovered and supplied again to the reactor. Can also be adopted.

In order to control the reaction rate in the catalyst bed of the fluidized bed and the height of the fluidized bed, particles substantially inert to the reaction, for example, metal oxides such as silica, alumina, titania, zirconia and aluminosilicate, Alternatively, a composite metal oxide, silicon nitride, carbon, etc. may coexist with the catalyst. At this time, it is preferable that the particles substantially inactive in the reaction have the same shape, particle size, and particle size distribution range as the catalyst particles.

In the present invention, the composition of the gas supplied to the reactor is such that the molar ratio of ammonia / propane is usually 0.1 to 0.1.
5, preferably 0.1 to 4, and the oxygen / ammonia molar ratio is usually 1 to 10, preferably 2 to 8. Within this range, the total selectivity of acrylonitrile and acrylic acid is excellent.

[0025]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples as long as the gist thereof is not exceeded. The propane conversion (%), target product selectivity (%), and target product yield (%) in the following Examples and Comparative Examples are calculated by the following formulas. Propane conversion rate (%) = (mol number of propane consumed / mol number of propane fed) × 100 Selectivity of target product (%) = (mol number of target product produced / mol number of consumed propane) × 100 Yield of target product (%) = (mol number of target product produced / mol number of propane fed) × 100 Reference Example 1 Preparation of Mo—V—Te—Nb composite oxide catalyst Mo containing SiO ₂ , A mixed metal oxide catalyst consisting of V, Te, and Nb was prepared as follows. Hot water 5.
1.68 kg of ammonium paramolybdate, 0.275 kg of ammonium metavanadate and 0.413 kg of telluric acid were dissolved in 68 liters to prepare a uniform aqueous solution. Further, 0.658 kg of silica sol having a silica content of 20 wt% and an aqueous solution containing niobium prepared by dissolving niobium oxide hydrate in an oxalic acid aqueous solution heated to 70 ° C. (niobium concentration 0.4 mol / kg)
A slurry was prepared by mixing 1.02 kg. This slurry was dried to remove water. Next, after heat-treating the dried product at about 300 ° C. until the smell of ammonia disappears,
Firing was performed at 600 ° C. for 2 hours in a nitrogen stream. The compositional analysis of the constituent elements of the obtained composite metal oxide was 90
_{t% -Mo 1 V 0.3 Te 0.17} Nb 0.12 O n + 10wt%
It was -SiO _2. Reference Example 2 Preparation of Mo-V-Te-Nb mixed metal oxide activator Preparation was performed in the same manner as in Reference Example 1 except that the amount of telluric acid used was 0.485 kg, and the constituent element composition was 90 w.
_{t% -Mo 1 V 0.3 Te 0.21} Nb 0.12 O n + 10wt
% To obtain a composite metal oxide having -SiO _2. Comparative Example 1 680 g of the composite metal oxide catalyst prepared in Reference Example 1 was loaded into a stainless steel fluidized bed reactor having an inner diameter of 50 mm. Nitrogen gas was introduced from the bottom of the reactor at a flow rate of 1218 NL / hr, the pressure at the reactor outlet was maintained at 90 kPa (gauge), and the temperature of the catalyst layer was raised to 390 ° C. in the electric furnace. Then, the supply of oxygen, ammonia and propane was started as follows. That is, the oxygen concentration in the gas at the reactor outlet is about 2% when all the components are vaporized while keeping the supply gas amount and the reactor outlet pressure almost constant.
Therefore, the supply amounts of oxygen, ammonia, and propane gas were increased and the supply amount of nitrogen was decreased. By repeating this operation, the composition of the gas finally supplied was adjusted to be propane / ammonia / oxygen / nitrogen = 1 / 1.2 / 3/12 on a molar ratio basis. During the operation of supplying gas with this composition, the temperature of the catalyst layer rises due to heat generation due to the gas phase catalytic oxidation reaction of propane and ammonia, but the target reaction temperature is 445 ° C.
The temperature was raised up to 445 ° C. by controlling the temperature of the electric furnace at any time until the temperature reached (1). In addition, at the reaction execution temperature, SV = 1790 hr ⁻¹ . When the reaction was started in this way and the reaction results were obtained about 2 hours later, the propane conversion was 88.0%, the acrylonitrile selectivity was 52.3%, and the acrylic acid selectivity was 3.3%. The reaction results were further continued, and the reaction results after 370 hours and 722 hours are shown in Table-1.

Then, 734.5 hours later, molybdenum trioxide was added.
(MoO₃) 8 g was added to the reactor. In addition, 89
After 1.5 hours, tellurium trioxide (TeO)₃) 2g reactor
Was added to. The reaction results immediately after these are shown in Table 1.
Repeat the addition of tellurium trioxide as shown in Table 1.
It was Furthermore, after 1027.5 hours, molybdic acid (H ₂
MoO_Four) Add 4 g to the reactor and repeat this procedure
It was The results are summarized in Table-1. Example 1 The whole amount of the catalyst extracted after stopping in Comparative Example 1 was fluidized again.
The reactor was filled and the reaction was started in the same manner as in Comparative Example 1.
(In addition, the time to restart the reaction is displayed as from 1190 hours.
It ) 2 hours after the restart of the reaction, the propane conversion was 84.5.
%, Acrylonitrile selectivity 48.3%, acrylic acid selection
The selection rate was 3.2%. Continue the reaction for 130
The reaction results after 0 hours are shown in Table-2. After 1303 hours
In addition, withdraw 30g of catalyst from the reactor, and immediately after that
Composition formula 90 wt% -M prepared as described in Consideration 2
o₁ V_0.3 Te_0.21 Nb_0.12O_n+ 10wt% -Si
O₂30 g of the composite metal oxide represented by Addition
The subsequent reaction results are shown in Table-2. Same operation at 1405
I went there a while later. Table 2 shows the changes in reaction results.

[0027]

[Table 1]

[0028]

[Table 2]

The following can be seen from Table-1 and Table-2. Immediately after the addition of TeO ₃ and H ₂ MoO ₄ which are not complex metal oxides, the acrylonitrile (AN) and acrylic acid (AN) selectivity is slightly improved (T).
735 (h) and 892 before and after the addition of eO _3.
The AN selectivity of (h) is 47.6% and 49.1%, A
Selectivities of A are 2.9% and 3.0%, 1026 (h) and 1028 (h) before and after adding H ₂ MoO _4.
Has AN selectivity of 48.4% and 49.2%, AA selectivity of 3.0% and 3.2%), but TeO ₃ and H ₂
Even if MoO ₄ is continuously added, the AN selectivity is gradually decreased (the TeO ₃ addition is the first and last 892.
AN selectivity of (h) and 1026 (h) is 49.1%.
And 48.4%, the AN selectivities of 1028 (h) and 1148 (h) at the beginning and end of the addition of H ₂ MoO ₄ are 49.2% and 48.4%).

Further, the propane (PPA) conversion rate decreased (892 (h), 1026 (h), 1028 (h) and 1148 (h), the PPA conversion rate was 84.5%, 83.
5%, 84.1% and 84.1%)
It can be seen that the yields of AA and AA hardly improve.
Then, since the pressure inside the fluidized bed reactor increased, the reaction was stopped at 1190 hours after the start of the reaction and the inside was observed. As a result, a large amount of silver-white substance was attached to the upper part of the reactor. Was observed. When elemental analysis and powder X-ray diffraction measurement of this deposit were performed, an alloy-like thin piece containing tellurium metal and molybdenum trioxide (MoO ₃ ) and Te, Fe, Cr was detected.

Immediately after the addition of the mixed metal oxide of the present invention, the selectivity of AN and AA was improved (the AN of 1300 (h) and 1304 (h) before and after the addition of the mixed metal oxide of the present invention). Selectivities are 46.5% and 47.
2%, AA selectivity is 3.0% and 3.2%), and continued to be improved by subsequent addition (1 added at the second time).
406 (h) and 1470 64 hours later
The AN selectivity of (h) is 48.7% and 49.7%, A
A selectivity 3.3% and 3.3%).

The PPA conversion rate also continued to improve (1
The PPA conversion rates of 304 (h), 1394 (h), 1406 (h) and 1470 (h) are 83.4%,
84.4%, 85.2% and 86.1%)
The yield and the AA yield were also improved compared to before the addition of the complex metal oxide (1300 (h) before addition and 1 after addition).
The AN yields of 470 (h) are 38.4% and 42.8.
%, AA yields 2.5% and 2.8%).

Then, substantially no pressure rise in the fluidized bed reactor was confirmed.

[0034]

INDUSTRIAL APPLICABILITY According to the present invention, acrylonitrile and / or acrylic acid, which is useful as an industrial raw material, can be produced for a long period of time by a gas phase catalytic oxidation reaction of propane in the presence of a complex metal oxide catalyst containing molybdenum, vanadium and tellurium. Since it can be stably produced in a high yield over a long period of time, it is very useful industrially.

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Claims (8)

[Claims] 1. A fluidized bed reactor is used to produce acrylonitrile and / or acrylic acid by subjecting propane to a gas phase catalytic oxidation reaction with ammonia and oxygen in the presence of a mixed metal oxide catalyst containing molybdenum, vanadium and tellurium. In this case, a method for producing acrylonitrile and / or acrylic acid is characterized in that a complex metal oxide containing molybdenum and tellurium is added to the reaction system as an activator. 2. The complex metal oxide catalyst comprises molybdenum, vanadium, X, Y and oxygen (X is tellurium or tellurium and antimony, Y is niobium, tantalum, tungsten, titanium, antimony, aluminum, zirconium, chromium, manganese, (Including one or more elements selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, palladium, platinum, bismuth, boron, indium, phosphorus, germanium, rare earth elements, alkali metals, and alkaline earth metals) The method for producing acrylonitrile and / or acrylic acid according to claim 1, which is a complex metal oxide. 3. The composite metal oxide catalyst is molybdenum (M
o), vanadium (V), the existence ratios of X and Y are as follows: 0.25 <rMo <0.98 0.003 <rV <0.5 0.003 <rX <0.5 0 ≦ rY <0 .5 (provided that rMo, rV, rX and rY represent the mole fractions of Mo, V, X and Y with respect to the total of the above components excluding oxygen).
The method for producing acrylonitrile and / or acrylic acid according to 1. 4. A complex metal oxide containing molybdenum and tellurium is molybdenum, vanadium, X, Y and oxygen (X is tellurium or tellurium and antimony, Y is niobium, tantalum, tungsten, titanium, antimony,
Aluminum, zirconium, chromium, manganese, iron,
Composite metal containing one or more elements selected from the group consisting of ruthenium, cobalt, rhodium, nickel, palladium, platinum, bismuth, boron, indium, phosphorus, germanium, rare earth elements, alkali metals, alkaline earth metals) The method for producing acrylonitrile and / or acrylic acid according to any one of claims 1 to 3, which is an oxide. 5. A composite metal oxide containing molybdenum and tellurium is molybdenum (Mo), vanadium (V), X.
And the abundance ratio of Y is 0.25 <rMo <0.98 0.003 <rV <0.5 0.003 <rX <0.5 0 ≦ rY <0.5 (provided that rMo, rV , RX and rY represent the mole fractions of Mo, V, X and Y with respect to the total of the above components excluding oxygen).
The method for producing acrylonitrile and / or acrylic acid according to 1. 6. The molybdenum and / or tellurium mole fraction of the composite metal oxide containing molybdenum and tellurium added as an activator to the reaction system is such that the molybdenum and / or tellurium of the composite metal oxide catalyst present in the reaction system at the time of addition are Alternatively, the method for producing acrylonitrile and / or acrylic acid according to any one of claims 1 to 5, which has a molar fraction of tellurium or more. 7. The composite metal oxide containing molybdenum and tellurium, which is added as an activator to the reaction system, has a propane conversion rate of 9% with respect to the propane conversion rate 24 hours after the start of the reaction.
The method for producing acrylonitrile and / or acrylic acid according to any one of claims 1 to 6, which is added after the content becomes 5% or less. 8. The weight of the particles in the reactor after adding the composite metal oxide containing molybdenum and tellurium to be added to the reaction system as an activator is 90% to 90% of the weight of the particles in the reactor at the start of the reaction. Addition so as to be 110%.
The method for producing acrylonitrile and / or acrylic acid according to any one of 1.