JPH11169716A - Catalyst for producing unsaturated nitrile and / or unsaturated carboxylic acid - Google Patents

Abstract

(57) [abstract] (with correction) [PROBLEMS] High activity, little decrease in activity over time,
Provided is a catalyst for producing unsaturated nitrile and / or unsaturated carboxylic acid from alkane. A catalyst that satisfies the following conditions 1) to 4). 1) It contains a composite oxide containing molybdenum, vanadium, tellurium, niobium and oxygen as essential components. 2) X
In a line diffraction pattern, show diffraction peaks at nine diffraction angles 2θ (°). 3) In X-ray diffraction, diffraction angle 2θ
When the intensity of the diffraction peak at 22.1 ± 0.3 ° is 100, the intensity at 27.3 ± 0.3 ° is 5 to 100 or 28.2.
The strength at ± 0.3 ° is 20 to 150. 4) When the X-ray diffraction of the catalyst was measured by adding ZnO as an internal standard substance, (weight of added ZnO / weight of collected catalyst) × (2θ = intensity of diffraction peak at 22.1 ± 0.3 ° / 2θ)
= 34.4 ± 0.3 °).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a catalyst used for producing unsaturated nitriles and / or unsaturated carboxylic acids by gas phase catalytic oxidation of alkanes.

[0002]

2. Description of the Related Art Unsaturated nitriles such as acrylonitrile and methacrylonitrile are used as intermediate materials for synthetic resins, synthetic fibers and synthetic rubbers, while unsaturated carboxylic acids such as acrylic acid and methacrylic acid are used for synthetic resins, paints and adhesives. It is industrially important as a raw material for plasticizers and the like. Conventionally, these unsaturated nitriles and unsaturated carboxylic acids are produced by a gas-phase catalytic oxidation reaction of an alkene as a raw material. For example, it is economically advantageous to use inexpensive propane or isobutane with propylene or isobutene. Extensive research has been conducted on catalysts that make this possible, and as a result, many catalysts have been reported.

The present inventors have proposed molybdenum, vanadium,
It has already been proposed that a composite metal oxide catalyst containing tellurium as an essential component is useful, and that it has a specific crystal structure and thus has excellent catalytic activity. For example, in JP-A-5-208136 and JP-A-6-279351, in X-ray diffraction, 2θ = 22.1 °, 2θ
A catalyst having diffraction peaks at 8.2 °, 36.2 °, 45.2 °, and 50.0 ° produces unsaturated nitriles and unsaturated carboxylic acids from alkanes with good yield. In Japanese Patent No. 232071, 2θ = 9.0 °, 2θ
It has been proposed that a catalyst having diffraction peaks at 2.1, 27.3, 29.2, and 35.4 can produce unsaturated nitriles from alkanes in good yield.

[0004]

However, the former is still inadequate in terms of the alkane conversion activity, while the latter, although the initial performance of the gas-phase catalytic oxidation reaction reaches a prima facie level, is not satisfactory. There is a problem that the stability over time of the performance is not yet sufficient.

[0005]

Means for Solving the Problems The present inventors have made intensive studies in view of the above problems, and as a result, it has been found that a catalyst composed of a specific constituent element and having a specific crystal structure can be produced from an alkane in a high yield. The inventors have found that they produce unsaturated nitriles and / or unsaturated carboxylic acids and have excellent stability over time of the catalyst, and have reached the present invention. That is, the gist of the present invention is a catalyst for producing an unsaturated nitrile and / or an unsaturated carboxylic acid from an alkane satisfying the following conditions (1) to (4).

(1) Molybdenum, vanadium, X, Y and oxygen (X is at least one of tellurium and antimony, Y is niobium, tantalum, tungsten, titanium, aluminum, zirconium, chromium, manganese,
Iron, ruthenium, cobalt, rhodium, nickel, palladium, platinum, bismuth, boron, indium, phosphorus,
(Indicating one or more elements selected from the group consisting of rare earth elements, alkali metals, and alkaline earth metals).

(2) To show a diffraction peak at the following diffraction angle 2θ (°) in an X-ray diffraction pattern. Diffraction angle 2θ (°) ------------------------- 9.0 ± 0.3 22.1 ± 0.3 27.3 ± 0 0.3 28.2 ± 0.3 29.2 ± 0.3 35.4 ± 0.3 36.2 ± 0.3 45.2 ± 0.3 50.0 ± 0.3

(3) In the X-ray diffraction pattern, the diffraction angle 2θ
When the intensity of the diffraction peak at 22.1 ± 0.3 ° is 100, the intensity of the diffraction peak at 2θ = 27.3 ± 0.3 ° is 5
-100, the intensity of the diffraction peak at a diffraction angle 2θ = 28.2 ± 0.3 ° is 20-150. Exists.

(4) When the X-ray diffraction of the catalyst was measured by adding ZnO as an internal standard substance, the diffraction peak of (2θ = 22.1 ± 0.3 °) was obtained by (weight of added ZnO / weight of collected catalyst). Intensity / 2θ = intensity of diffraction peak at 34.4 ± 0.3 °) is 0.05 or more.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The catalyst used in the present invention is molybdenum, vanadium,
X, Y and oxygen (X is at least one of tellurium and antimony, Y is niobium, tantalum, tungsten, titanium, aluminum, zirconium, chromium, manganese, iron, ruthenium, cobalt, rhodium, nickel, palladium, platinum, Bismuth, boron, indium, phosphorus, a rare earth element, an alkali metal, and at least one element selected from the group consisting of alkaline earth metals). Except for the proportion of each of the above essential components, the following formula: 0.25 <rMo <0.98 0.003 <rV <0.5 0.003 <rX <0.50 ≦ rY <0.5 (where rMo , RV, rX, rY represent the mole fractions of Mo, V, X, and Y with respect to the sum of the above essential components excluding oxygen). Catalyst is used. As the Y component, niobium, tantalum, tungsten, and titanium are preferable, and niobium is particularly preferable. The ratio of the essential components is particularly preferably in the range of the following formula. 0.4 <rMo <0.8 0.05 <rV <0.4 0.03 <rX <0.25 0.02 <rY <0.25

The catalyst of the present invention has the following diffraction angle 2 in the X-ray diffraction pattern measured using Cu-Kα ray.
The diffraction peak is shown at θ (°). Diffraction angle 2θ (°) Relative intensity ----------------------- ------------------- --- 9.0 ± 0.3 0.5 to 30 22.1 ± 0.3 100 27.3 ± 0.3 5 to 100 28.2 ± 0.3 20 to 150 29.2 ± 0.3 2-40 35.4 ± 0.3 2-40 36.2 ± 0.3 5-60 45.2 ± 0.3 2-40 50.0 ± 0.3 2-40

The catalyst of the present invention may have a diffraction peak derived from a binder, a carrier, a diluent and the like contained in the catalyst, in addition to the diffraction peak derived from the above-mentioned composite oxide. One of the features of the catalyst of the present invention is that two types of conventionally known crystal systems are mixed at a specific ratio. That is, the catalyst of the present invention shows that the intensity of the diffraction peak at a diffraction angle 2θ = 22.1 ± 0.3 ° is 1 in the X-ray diffraction pattern.
The intensity (relative intensity) of the diffraction peak at a diffraction angle 2θ = 27.3 ± 0.3 ° when the angle is set to 00 is 5 to 100, preferably 10
And the intensity (relative intensity) of the diffraction peak at a diffraction angle of 28.2 ± 0.3 ° is 20 to 150, preferably 25 to 120.
It is. If the intensity (relative intensity) of the diffraction peak at a diffraction angle 2θ = 27.3 ± 0.3 ° is smaller than 5, the conversion of the alkane becomes insufficient, while if it exceeds 100, the stability of the catalyst over time becomes insufficient. is there. Also, the diffraction angle 2θ = 28.2
If the intensity (relative intensity) of the diffraction peak at ± 0.3 ° is less than 20, the selectivity of the nitrile or the stability over time is insufficient, while if it exceeds 150, the alkane conversion is insufficient. Is often observed.

Further, when the intensity of the diffraction peak at the diffraction angle 2θ = 22.1 ± 0.3 ° is defined as 100, it is preferable that the other diffraction peaks show the above relative intensities. The catalyst of the present invention is used as an internal standard substance in the National Institute of St.
In the X-ray diffraction pattern measured by Cu-Kα ray using ZnO of standard reagent No. 674a provided by andards and Technology, 2θ = 34.4 ± 0.
The intensity of the diffraction peak of 3 ° and the intensity of the diffraction peak of 2θ = 22.1 ± 0.3 ° derived from the composite oxide constituting the catalyst are (weight of added ZnO / weight of collected catalyst).
× (2θ = 22.1 ± 0.3 ° diffraction peak intensity / 2θ = 3
(The intensity of the diffraction peak at 4.4 ± 0.3 °) is 0.
05 or more, preferably 0.2 or more. This value indicates the concentration of the composite oxide constituting the catalyst. If the value is less than 0.05, the generation of crystals is insufficient, and the conversion of alkanes and the generation of nitrile are insufficient. It is to be noted that ZnO is added to the catalyst sample in a weight ratio of about 1/100 to about an equal amount and mixed well before being used for measurement.

The method for preparing the catalyst of the present invention is not particularly limited, and includes a method of preparing a solution or a slurry of the raw material of the composite oxide in water or an organic solvent, and a method of mixing the raw materials of the composite oxide and conducting a high-temperature solid-state reaction Are well known. In order to obtain a catalyst having better performance, the former method, particularly a method of preparing a solution or a slurry-like aqueous liquid containing each component, followed by drying and calcining, is preferred.

The raw materials for preparing the catalyst of the present invention include carboxylate, ammonium carboxylate, ammonium halide, oxide, oxyacid and salts thereof, halide, hydroacid, acetylacetonate, alkoxide, Compounds such as halides or metals can be used after being solubilized with an appropriate reagent. For example,
As a method for producing a catalyst comprising a composite oxide containing molybdenum, vanadium, tellurium and niobium, an aqueous solution of ammonium metavanadate, an aqueous solution of telluric acid, an aqueous solution of niobium ammonium oxalate and an aqueous solution of ammonium paramolybdate are used. It is sequentially added in a quantitative ratio such that the atomic ratio of each metal element becomes a predetermined ratio, and dried by an evaporation to dryness method, a spray drying method, a freeze drying method, a vacuum drying method, etc. to obtain a dried product, and then It can be obtained by baking the obtained dried product.

The firing can be arbitrarily adopted depending on the properties and scale of the dried product, but heat treatment on an evaporating dish or heat treatment in a heating furnace such as a rotary furnace or a fluidized firing furnace is generally used. . Further, a plurality of these processes may be combined. These firing conditions also vary depending on the firing method, but the temperature is usually 200 to 700 ° C, preferably 250 to 650.
C, time is usually 0.5 to 30 hours, preferably 1 to 1 hour.
Performed for 0 hours. The calcination may be performed in an oxygen atmosphere, but is preferably performed in the absence of oxygen in order to obtain the catalyst of the present invention. Specifically, nitrogen, argon,
This is performed in an atmosphere of an inert gas such as helium or in a vacuum.

The catalyst comprising the composite oxide thus produced may be used alone, but may be any of well-known carrier components,
For example, it may be used as a mixture containing about 1 to 90% by weight of silica, alumina, titania, zirconia, aluminosilicate, diatomaceous earth and the like. Such a carrier component may be added at the same time as preparing the solution or slurry of the catalyst raw material, or may be added after the solution or slurry is dried. Alternatively, the catalyst particles after calcination and these carrier component particles may be physically mixed and used.

Further, the composite oxide catalyst produced as described above is treated at 200 to 600 ° C. in an atmosphere containing oxygen.
By performing the heat treatment again for several seconds to 10 hours, the yield or selectivity of the unsaturated carboxylic acid can be improved. The catalyst of the present invention is particularly effective for producing an unsaturated nitrile and / or an unsaturated carboxylic acid by subjecting an alkane having 2 to 8 carbon atoms to a gas phase catalytic oxidation reaction. Furthermore, considering the industrial importance of the product, it is suitably used for the production of acrylonitrile and / or acrylic acid from propane and the production of methacrylonitrile and / or methacrylic acid from isobutane. Depending on the selection of reaction operation conditions, it is possible to simultaneously produce acrylonitrile and acrylic acid from propane, for example, in the presence of ammonia. There is an advantage that it can be manufactured simultaneously with equipment.

The conditions for the gas-phase catalytic oxidation reaction of the alkane are as follows.
And the gas hourly space velocity SV in the gas phase reaction is usually 100 to 10,000 hr ^-1 , preferably 3 to 100 hr.
The range is from 00 to 6000 hr ^-1 . The gas phase contact reaction is
Usually, the reaction is carried out under atmospheric pressure, but may be carried out under low pressure or low pressure. As a diluent gas for adjusting the space velocity and the oxygen partial pressure, an inert gas such as nitrogen, argon, helium, or carbon dioxide can be used. The reaction system may be a fixed bed, a fluidized bed, or the like. However, since the reaction is an exothermic reaction, the fluidized bed system is easier to control the reaction temperature.

Specifically, when acrylonitrile is produced from propane, the proportion of oxygen supplied to the reaction system has a large effect on the selectivity of acrylonitrile to be produced, and the proportion of oxygen is 0.2 to 4 mol based on propane. The range of double amount is preferred. Within this range, a high acrylonitrile selectivity can be exhibited. The ratio of ammonia supplied to the reaction system is 0.1 to 3 with respect to propane.
A molar range is preferred.

When acrylic acid is produced from propane, the proportion of oxygen supplied to the reaction system is preferably in the range of 0.1 to 5 times the molar amount of propane. Furthermore,
By supplying water vapor to the reaction system, the selectivity of acrylic acid may be improved, and the ratio of the water vapor is 40 mol times or less with respect to propane. Furthermore, when trying to produce unsaturated nitrile and unsaturated carboxylic acid, for example, acrylonitrile and acrylic acid at the same time, the composition of the gas supplied to the reactor is such that the molar ratio of ammonia / propane is:
Usually 0.1-5, preferably 0.1-4, oxygen /
The molar ratio of ammonia is usually 2 to 10, preferably 3 to
8 Within this range, the total selectivity of the unsaturated nitrile and the unsaturated carboxylic acid is excellent.

[0022]

EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples unless it exceeds the gist. The alkane conversion (%), target product selectivity (%), and target product yield (%) in the following Examples and Comparative Examples are each calculated by the following formulas.

Conversion of alkane (%) = (moles of alkane consumed / moles of supplied alkane) × 100 Selectivity (%) of target product = (moles of target product formed / moles of alkane consumed) ) × 100 Yield (%) of target product = (moles of target product / moles of supplied alkane) × 100

<Catalyst Production Example 1> Experimental formula Mo ₁ V _0.3 Te
_0.23 Nb _0.12 O _n catalyst composite oxide was supported on the SiO ₂ of (SiO ₂ 10% by weight of the total catalyst) was prepared as follows. 1.38 kg of ammonium paramolybdate, 0.275 kg of ammonium metavanadate, and 0.413 kg of telluric acid were dissolved in 5.68 liters of warm water to prepare a uniform aqueous solution. Further, 0.972 kg of a silica sol having a silica content of 20 wt% and 1.422 kg of an aqueous niobium ammonium oxalate solution having a niobium concentration of 0.659 mol / kg were mixed to prepare a slurry. The slurry was dried to remove water. Next, the dried product is removed for about 300 until the smell of ammonia disappears.
After the heat treatment at ℃, it was baked at 600 ℃ for 2 hours in a nitrogen stream.

When the obtained catalyst was subjected to X-ray diffraction measurement using Cu-Kα ray as an X-ray source, diffraction peaks were observed at the following positions and intensities. Also, 0.1672g of this catalyst
After mixing 0.0518 g of ZnO of standard reagent No. 674a provided by National Institute of Standards and Technology, X-ray diffraction measurement was carried out, and it was found that (weight of added ZnO / weight of collected catalyst) × (2θ = 22.1 ± 2. 0.3 ° diffraction peak intensity / 2θ = 34.4 ± 0.3 ° diffraction peak intensity) = 0.79.

[0026]

Example 1 Catalyst obtained in Catalyst Production Example 1
0.25 g was charged into a fixed bed flow type reactor, and the reaction temperature was 430
C. and the space velocity SV were fixed at about 2000 h ^-1 , and a gas was supplied at a molar ratio of propane: ammonia: air = 1: 1.2: 15 to perform a gas phase catalytic oxidation reaction. Table 1 shows the results 5 hours and 1300 hours after the start of the reaction.

Example 2 Catalyst obtained in Catalyst Production Example 1
0.55 g was charged into a fixed bed flow type reactor, and the reaction temperature was 400
C. and the space velocity SV were fixed at about 1870 h ^-1 , and a gas was supplied at a molar ratio of propane: air: steam = 1: 15: 14 to perform a gas phase catalytic oxidation reaction. The results after 5 hours are shown in Table-2.

Example 3 Catalyst obtained in Catalyst Production Example 1
0.1 g was charged into a fixed bed flow type reactor, and the reaction temperature was 435.
° C, propane: ammonia: air = 1: 0.3: 5.4
, The mass-based space velocity of propane WHSV = 2.
A gas was supplied at 5 / h to perform a gas phase catalytic oxidation reaction. 5
Table 3 shows the results after the lapse of time.

<Catalyst Production Example 2> 2 at 600 ° C. in a nitrogen stream
The procedure was the same as in Catalyst Production Example 1, except that the firing was carried out at 350 ° C. for 4 hours in an air stream instead of firing for an hour. X-ray diffraction measurement of the obtained catalyst was performed in the same manner as in Catalyst Production Example 1.
Diffraction peaks were observed at the following positions and intensities. Also,
After mixing 0.1755 g of this catalyst and 0.0630 g of ZnO, an X-ray diffraction measurement was carried out to find that (weight of added ZnO / weight of collected catalyst) × (2θ = intensity of diffraction peak at 22.1 ± 0.3 ° / 2θ) = Intensity of diffraction peak at 34.4 ± 0.3 °) =
0.045.

[0031]

<Catalyst Production Example 3> Experimental formula Mo ₁ V _0.3 Te
_0.2 Nb _0.12 O _n catalyst composite oxide supported on SiO ₂ of (SiO ₂ 10% by weight of the total catalyst) was prepared as follows. 1.38 kg of ammonium paramolybdate, 0.275 kg of ammonium metavanadate, and 0.359 kg of telluric acid were dissolved in 5.68 liters of warm water to prepare a uniform aqueous solution. Further, 0.950 kg of silica sol having a silica content of 20 wt% and 1.422 kg of an aqueous niobium ammonium oxalate solution having a niobium concentration of 0.659 mol / kg were mixed to prepare a slurry. The slurry was dried to remove water. Next, the dried product is removed for about 300 until the smell of ammonia disappears.
After the heat treatment at ℃, it was baked at 600 ℃ for 2 hours in a nitrogen stream.

When the obtained catalyst was subjected to X-ray diffraction measurement in the same manner as in Catalyst Production Example 1, diffraction peaks were observed at the following positions and intensities. In addition, 0.1548 g of this catalyst and ZnO
After mixing 0598g, X-ray diffraction measurement was performed.
(Weight of added ZnO / weight of collected catalyst) × (2
θ = 22.1 ± 0.3 ° diffraction peak intensity / 2θ = 34.4 ± 0.
The intensity of the diffraction peak at 3 °) was 0.75.

[0034]

<Catalyst Production Example 4> Experimental formula Mo ₁ V _0.3 Te
_0.3 Nb _0.1 O _n catalyst composite oxide supported on SiO ₂ of (SiO ₂ 10% by weight of the total catalyst) was prepared as follows. 1.38 kg of ammonium paramolybdate, 0.275 kg of ammonium metavanadate, and 0.538 kg of telluric acid were dissolved in 5.68 liters of warm water to prepare a uniform aqueous solution. Further, 1.009 kg of a silica sol having a silica content of 20 wt% and 1.185 kg of an aqueous niobium ammonium oxalate solution having a niobium concentration of 0.659 mol / kg were mixed to prepare a slurry. The slurry was dried to remove water. Next, the dried product is removed for about 300 until the smell of ammonia disappears.
After the heat treatment at ℃, it was baked at 600 ℃ for 2 hours in a nitrogen stream.

The obtained catalyst was subjected to X-ray diffraction measurement in the same manner as in Catalyst Production Example 1. As a result, diffraction peaks were observed at the following positions and intensities. In addition, 0.1548 g of this catalyst and ZnO
After mixing 0598g, X-ray diffraction measurement was performed.
(Weight of added ZnO / weight of collected catalyst) × (2
θ = 22.1 ± 0.3 ° diffraction peak intensity / 2θ = 34.4 ± 0.
The intensity of the diffraction peak at 3 °) was 0.75.

[0037]

<Comparative Examples 1 to 3> Catalysts obtained in Catalyst Production Examples 2 (Comparative Example 1), 3 (Comparative Example 2), and 4 (Comparative Example 3)
The procedure was performed in the same manner as in Example 1 except that 0.25 g was used. The results are shown in Table 1.

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

[Table 3]

[0042]

According to the present invention, acrylonitrile which is useful as an industrial raw material by a gas phase catalytic oxidation reaction of alkane,
Unsaturated nitriles such as acrylic acid and unsaturated carboxylic acids can be produced with high yield and selectivity over a long period of time.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI B01J 27/18 C07C 51/00 C07C 51/00 57/05 57/05 253/24 253/24 255/08 255/08 C07B 61 / 00 300 // C07B 61/00 300 B01J 23/64 103Z

Claims (5)

[Claims] 1. A catalyst for producing an unsaturated nitrile and / or an unsaturated carboxylic acid from an alkane satisfying the following conditions (1) to (4). (1) Molybdenum, vanadium, X, Y and oxygen (X
Is at least one of tellurium and antimony, Y
From niobium, tantalum, tungsten, titanium, aluminum, zirconium, chromium, manganese, iron, ruthenium, cobalt, rhodium, nickel, palladium, platinum, bismuth, boron, indium, phosphorus, rare earth elements, alkali metals, alkaline earth metals (Indicating one or more elements selected from the group consisting of). (2) In the X-ray diffraction pattern, the following diffraction angle 2θ
Show the diffraction peak in (°). Diffraction angle 2θ (°) ------------------------- 9.0 ± 0.3 22.1 ± 0.3 27.3 ± 0.3 28.2 ± 0.3 29.2 ± 0.3 35.4 ± 0.3 36.2 ± 0.3 45.2 ± 0.3 50.0 ± 0.3 (3) In X-ray diffraction, diffraction angle 2θ = 22.1 ± 0.3
The diffraction angle 2 when the intensity of the diffraction peak of ° is 100.
The intensity of the diffraction peak at θ = 27.3 ± 0.3 ° is 5 to 10
0, the intensity of the diffraction peak at a diffraction angle 2θ = 28.2 ± 0.3 ° is 20 to 150. (4) When X-ray diffraction of the catalyst was measured by adding ZnO as an internal standard substance, (weight of added ZnO / weight of collected catalyst) × (2θ = intensity of diffraction peak at 22.1 ± 0.3 ° / 2θ) = 34.4 ± 0.3 °). 2. The existence ratio of an essential component excluding oxygen in the composite oxide is represented by the following formula: 0.25 <rMo <0.98 0.003 <rV <0.5 0.003 <rX <0.50 ≦ rY <0.5 (where rMo, rV, rX, rY represent the molar fraction of Mo, V, X and Y with respect to the sum of the above essential components excluding oxygen). 2. The catalyst according to 1. 3. The method according to claim 1, wherein niobium is an essential component.
The catalyst according to the above. 4. A method for producing an unsaturated carboxylic acid, wherein the gas phase catalytic oxidation reaction of an alkane is carried out in the absence of ammonia in the presence of the catalyst according to any one of claims 1 to 3. 5. An unsaturated nitrile and / or unsaturated carboxylic acid, wherein a gas phase catalytic oxidation reaction of propane and / or isobutane is carried out in the presence of the catalyst according to any one of claims 1 to 3. Manufacturing method.