JPH1057813A - Method for producing composite metal oxide catalyst and method for producing acrylic acid using the catalyst - Google Patents

Abstract

(57) [Problem] To provide a method for producing a composite metal oxide catalyst capable of efficiently producing acrylic acid from propane, and a method for producing acrylic acid using the catalyst. SOLUTION: In a method for producing a composite metal oxide catalyst for producing acrylic acid by subjecting propane to a gas phase catalytic oxidation reaction, a solution or slurry containing molybdenum, vanadium, and tellurium and / or antimony is dried,
Next, after subjecting the obtained dried product to a heat treatment in the substantially absence of oxygen, a method for producing a composite metal oxide catalyst characterized by further performing a heat treatment in an oxygen-containing gas stream, and the method according to claim 1, A method for producing acrylic acid by subjecting propane to a gas phase catalytic oxidation reaction using a catalyst produced by the method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a composite metal oxide catalyst and a method for producing acrylic acid using the catalyst. More specifically, a method for producing a composite metal oxidation catalyst comprising treating a solution or slurry containing a catalyst component under specific conditions, and producing acrylic acid by subjecting propane to a gas phase catalytic oxidation reaction using the catalyst. About the method.
Acrylic acid is industrially important as a raw material for various synthetic resins, superabsorbent materials, paints and the like.

[0002]

2. Description of the Related Art Conventionally, the most common method for producing acrylic acid is a method in which propylene is used as a raw material to react in a gaseous phase with oxygen in the presence of a catalyst at a high temperature, followed by a two-stage production via acrolein. It is known as a typical method. On the other hand, due to the price difference between propane and propylene, interest has been growing in developing a method for producing acrylic acid by using gaseous catalytic oxidation reaction in the presence of a catalyst using inexpensive propane as a starting material.

An example of a catalyst for producing acrylic acid by subjecting propane to a gas phase catalytic oxidation reaction is Mo.
-Sb-PO-based catalysts (European Patent No. 0010902), VP-Te-O-based catalysts (Sai et al., Journa)
l of Catalysis, 1986, Vol.
101, p. 389), Bi-Mo-O catalyst (Japanese Unexamined Patent Application Publication No.
Molybdophosphoric acid catalyst treated with pyridine (Ueda et al., Chemistry Lett).
ers, 1995, p. 541), Fe-Cs-H-
PV-Mo-O based catalyst (Mizuno et al., Applied C
analysis A: General, 1995,
Vol. 128, p. L165) is known. The present inventors have also proposed a Mo-V-Te-XO-based catalyst (Japanese Patent Laid-Open No.
279351, JP-A-7-10801).

[0004]

However, these methods still do not satisfy the desired yield or selectivity of acrylic acid. An object of the present invention is to provide a method for producing a catalyst capable of efficiently producing acrylic acid in the production of acrylic acid by a gas phase catalytic oxidation reaction of propane, and a method for producing acrylic acid using the catalyst. It is in.

[0005]

Means for Solving the Problems The present inventors have made intensive studies to solve the above problems, and as a result, by treating a solution or slurry containing a catalyst component under specific conditions,
The inventors have found that a catalyst capable of efficiently producing acrylic acid can be obtained, and have completed the present invention.

That is, the present invention provides: In a method for producing a composite metal oxide catalyst for producing acrylic acid by reacting propane with a gas phase catalytic oxidation reaction,
After drying the solution or slurry containing molybdenum, vanadium, and tellurium and / or antimony, and then subjecting the resulting dried product to heat treatment substantially in the absence of oxygen,
Further, a method for producing a composite oxide catalyst characterized by performing a heat treatment in an oxygen-containing gas stream, and propane is subjected to a gas phase catalytic oxidation reaction using the catalyst produced by the method described in section 2.1 to produce acrylic acid. Method of manufacturing. Hereinafter, the present invention will be described in detail.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION

(1) Method for Producing Catalyst In the present invention, molybdenum, vanadium, tellurium and / or antimony, preferably molybdenum,
Vanadium, X, Y and O (X represents at least one element of tellurium and antimony, and Y represents niobium, tantalum, tungsten, titanium, aluminum,
At least one element selected from the group consisting of zirconium, chromium, manganese, iron, ruthenium, cobalt, rhodium, nickel, palladium, platinum, bismuth, boron, indium, phosphorus, rare earth elements, alkali metals and alkaline earth metals Is an essential component, and the ratio of each essential component to the total of the above essential components excluding oxygen is expressed by the following formula:

[0008]

[Number 2] _{0.25 <r Mo <0.98 0.003 <} r V <0.5 0.003 <r X <0.5 0.003 <r Y <0.5 ( where, r _Mo, r _V , r _X and r _Y represent the mole fractions of Mo, V, X and Y relative to the sum of the above essential components excluding oxygen), drying the solution or slurry containing the catalyst constituents, and then obtaining After heat-treating the dried product substantially in the absence of oxygen, it is further heat-treated in an oxygen-containing gas stream.

[0009] The method for producing the composite oxide catalyst is as follows.
The element X is Te and the element Y is Nb, ie, Mo _a V _b Te _c
For Nb _x O _n, process for the preparation of the precursor is as follows. To 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 sequentially added in an amount ratio such that the atomic ratio of each metal element becomes a predetermined ratio. Then, the dried product is dried by an evaporation to dryness method, a spray drying method, a freeze drying method, a vacuum drying method or the like to obtain a dried product, and then the obtained dried product is subjected to heat treatment. The method of the heat treatment can be arbitrarily adopted depending on the properties and scale of the dried product,
A method using a heating furnace such as a fluidized sintering furnace is generally used.
The reaction is performed at 0 to 650 ° C. for several minutes to 30 hours.

The raw materials of the catalyst precursor are not limited to those described above. For example, MoO ₃ , V ₂
Oxides such as O ₅ , V ₂ O ₃ , TeO ₂ , Nb ₂ O ₅ , M
oCl ₅ , VCl ₄ , VOCl ₃ , NbCl _{5 and} other halides, or oxyhalides, Mo (OC
_{2 H 5) 5, Nb (} OC 2 H 5) 5, VO (OC
₂ H _{5) 3,} alkoxides such as molybdenum acetylacetonate, can be used such as widely organometallic compound.

Also, when the element X is Sb, the element X is Te.
It is possible to prepare a catalyst precursor in the same manner as in the case of the above, and as the Sb raw material, Sb ₂ O ₃ , Sb ₂ O ₄ , Sb
OCl, SbCl _{3 and the} like can be used. In this case, by using a solution containing an oxoanion containing pentavalent V as the V raw material and using an antimony compound containing Sb having a trivalent valence as the Sb raw material, at least a part of V is reduced. It is preferable to use a catalyst precursor containing vanadium and antimony in which at least a part of Sb is oxidized to a pentavalent state.

The catalyst precursor thus obtained has sufficient activity as a solid catalyst as it is, but in the present invention, the catalyst precursor is further subjected to a heat treatment in an oxygen-containing gas stream. This makes it possible to further increase the catalyst performance, particularly the acrylic acid yield. The heating method in an oxygen-containing gas stream is generally performed by a heating furnace such as a rotary furnace or a fluidized-bed firing furnace.
The reaction is carried out at a temperature of 250 to 500 ° C., preferably 300 to 450 ° C., for about several seconds to 30 hours, preferably for 5 minutes to 10 hours.

The oxygen concentration in the oxygen-containing gas is not particularly limited, but if the concentration is too low, the treatment time will be prolonged. If the oxygen concentration is too high or the oxygen concentration is too high, the catalyst may be oxidative depending on the catalyst composition and the treatment time. Because it may be subject to
Usually, it is 0.1 to 40% by volume, preferably 0.5 to 25% by volume. Although the chemical explanation of this effect is still insufficient, it is presumed that the surface of the composite oxide catalyst is formed in a state effective for acrylic acid production by heat treatment in an oxygen-containing gas stream. . Although the catalyst proposed in the present invention may be used alone, a substance substantially inert to the present reaction, for example, silica, silicon carbide, diatomaceous earth,
Alumina, titania, zirconia and the like can be added as a carrier or a diluent. Further, it is molded into an appropriate shape and particle size depending on the scale and system of the reaction.

(2) Method for Producing Acrylic Acid In the present invention, the composition of the feed gas is not particularly limited, but the molar ratio of oxygen / propane is usually 0.1 to 10, preferably 0.1. ~ 5. Although the details of the mechanism of the oxidation reaction in the present invention are not clear, the oxidation reaction is carried out by oxygen atoms present in the above oxide or molecular oxygen present in the supply gas. When molecular oxygen is present in the feed gas, the molecular oxygen may be pure oxygen gas, but since purity is not particularly required, it is generally economical to use an oxygen-containing gas such as air. Further, nitrogen, argon, helium, carbon dioxide, water vapor, and the like can be supplied as a diluting gas for adjusting the space velocity and the partial pressures of the alkane and oxygen. The role of water vapor in this is not clear, but its supply is effective in improving the yield of acrylic acid. Further, by controlling the composition of the raw material gas supplied to the reactor and the conversion of propane, it is possible to suppress the sequential decomposition of the intended acrylic acid and to increase the selectivity of acrylic acid. . When such a method is adopted, the concentration of propane in the raw material gas supplied to the reactor is increased, the amount of acrylic acid generated in a single stream is increased, and acrylic acid is separated from the effluent from the reactor. After that, it is advantageous to employ the re-feeding of the gaseous substance containing unreacted propane to the reactor, since the substantial amount of propane converted to acrylic acid is increased.

The reactor system can employ any of a fixed bed, a fluidized bed and the like. However, since the reaction is an exothermic reaction, the fluidized bed system makes it easier to control the reaction temperature. The reaction is usually carried out at atmospheric pressure, but can also be carried out under low pressure or reduced pressure. The reaction can be carried out at a temperature of 270 to 450 ° C, and particularly preferably 280 to 400 ° C.
It is about. The gas hourly space velocity SV in the gas phase reaction is generally 100 to 10000 h ^-1 , preferably 300 to 600 h ^-1 .
0h ^-1 . When the gas phase catalytic oxidation reaction of propane is carried out by the method of the present invention, carbon monoxide, carbon dioxide, acetic acid, acrolein and the like are produced as by-products in addition to acrylic acid, but the amount of the produced is extremely small.

[0016]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples unless it exceeds the gist. The conversion (%), selectivity (%) and yield (%) in the following examples
Are represented by the following equations.

[0017]

## EQU3 ## Alkane conversion (%) = (moles of alkane consumed / moles of supplied alkane) × 100 Selectivity of acrylic acid (%) = (moles of acrylic acid produced / moles of alkane consumed) ) × 100 Yield (%) of acrylic acid = (moles of acrylic acid generated / moles of supplied alkane) × 100

[0018] Preparation empirical formula Mo ₁ of Reference Example 1 composite oxide catalyst _{V 0.3 Te 0.23 Nb 0.12 O n} / SiO 2 1
A composite metal oxide having 0% by weight was prepared as follows. 78.9 g of ammonium paramolybdate, 15.7 g of ammonium metavanadate, and 23.6 g of telluric acid were dissolved in 325 ml of warm water to prepare a uniform aqueous solution. Further, 117.5 g of an aqueous niobium ammonium oxalate solution having a niobium concentration of 0.456 mol / kg and 55.6 g of a silica sol having a silica concentration of 20% by weight were mixed to prepare a slurry. The slurry was dried to remove water. Then, the dried product is heated at about 300 ° C. until the smell of ammonia disappears.
Calcination was performed at 2 ° C for 2 hours.

Example 1 A catalyst prepared as in Reference Example 1 (Mo ₁ V _0.3 T
_{e 0.23 Nb 0.12 O n / SiO} 2 10 % by weight) was filled with 2g in a fixed bed flow type calciner, 380 while supplying air
Heat treatment was performed at 21 ° C. for 21 hours. 100 mg of the catalyst thus prepared was charged into a fixed bed flow reactor, and a reaction gas of propane: air = 1: 4 (volume) at a reaction temperature of 410 ° C. was 1.37 g-propane / g-catalyst. Table 1 shows the results of the gas-phase catalytic oxidation reaction performed at a time rate.

Examples 2 and 3 Using the catalyst prepared as in Example 1, under the same reaction gas composition and propane feed rate as in Example 1, propane was reacted at a reaction temperature of 400 ° C. and 420 ° C. A gas phase catalytic oxidation reaction was performed. The results are shown in Table 1.

[0021]

[Table 1]

Comparative Examples 1 and 2 Catalysts prepared as in Reference Example 1 (Mo ₁ V _0.3 T
using _{e 0.23 Nb 0.12 O n / SiO} 2 10 wt%),
400 ° C. under the same reaction gas composition and propane supply rate as in Example 1 without the heat treatment under the air flow.
Table 4 shows the results of the gas phase catalytic oxidation reaction at
It is shown in FIG.

[0023]

[Table 2]

[0024] was prepared in Reference Example 2 composite metal oxide having a prepared empirical formula _{Mo 1 V 0.3 Te 0.23 Nb 0.12} O n of the composite oxide catalyst as follows. 7 in 325 ml of hot water
8.9 g ammonium paramolybdate, 15.7
g of ammonium metavanadate and 23.6 g of telluric acid were dissolved to prepare a uniform aqueous solution. Further, 117.5 g of an aqueous solution of ammonium niobium oxalate having a niobium concentration of 0.456 mol / kg was mixed to prepare a slurry. The slurry was dried to remove water. Next, the dried product was heated at about 300 ° C. until the smell of ammonia disappeared, and then calcined at 600 ° C. for 2 hours in a nitrogen stream.
30 g of the composite metal oxide thus obtained was pulverized in a mortar, and the powder was dispersed in 100 ml of water to obtain a water-soluble slurry. This slurry was subjected to a heat treatment to obtain a powder solid. This solid is compressed to 5 mmφ using a tableting machine.
After molding into × 3 mmL, it was crushed, sieved to 16 to 28 mesh, and fired at 600 ° C. for 2 hours in a nitrogen stream.

Examples 4 and 5 Catalysts prepared as in Reference Example 2 (Mo ₁ V _0.3 T
was performed e _0.23 Nb _0.12 O _n) 2 hours of heat treatment under 2g was packed in a fixed bed flow type calciner 380 ° C. while feeding air. 550 mg of the catalyst thus prepared
Was charged into a fixed bed flow type reactor at a reaction temperature of 380 ° C. and 400 ° C., and propane: air: steam = 1: 15: 14.
Table 3 shows the results obtained by supplying a (volume) reaction gas at a rate of 0.10 g-propane / g-catalyst / hour and performing a gas phase catalytic oxidation reaction.

[0026]

[Table 3]

Comparative Examples 3 and 4 Catalysts prepared as in Reference Example 2 (Mo ₁ V _0.3 T
e _0.23 Nb _0.12 O _n ), without heat treatment under flowing air, at the same reaction gas composition and propane feed rate as in Example 4, gas phase catalytic oxidation at 380 ° C. and 400 ° C. The results of the reaction are shown in Table-4.

[0028]

[Table 4]

[0029]

According to the present invention, acrylic acid can be efficiently produced from propane.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical indication location C07C 57/05 C07B 61/00 300 // C07B 61/00 300 B01J 23/64 103Z

Claims (4)

[Claims] In a method for producing a composite metal oxide catalyst for producing acrylic acid by subjecting propane to a gas phase catalytic oxidation reaction, a solution or slurry containing molybdenum, vanadium, tellurium and / or antimony is dried. ,
Next, a method for producing a composite oxide catalyst, comprising subjecting the obtained dried product to a heat treatment substantially in the absence of oxygen, and further performing a heat treatment in an oxygen-containing gas stream. 2. The catalyst component contained in the solution or slurry contains molybdenum, vanadium, X, Y and O (X
Represents at least one element of tellurium and antimony, and Y represents niobium, tantalum, tungsten, titanium, aluminum, zirconium, chromium, manganese, iron, ruthenium, cobalt, rhodium, nickel,
Represents at least one element selected from the group consisting of palladium, platinum, bismuth, boron, indium, phosphorus, rare earth elements, alkali metals and alkaline earth metals)
Was an essential component of proportions of each essential component to the sum of the essential components except the oxygen, the following equation ## EQU1 ## _{0.25 <r Mo <0.98 0.003 <} r V <0.5 0. 003 <r _X <0.5 0.003 <r _Y <0.5 (where r _Mo , r _V , r _X and r _Y are the values of Mo, V, X and Y with respect to the sum of the above essential components excluding oxygen) 2. The method according to claim 1, wherein the method satisfies the following formula: 3. A heat treatment substantially in the absence of oxygen is performed for 3 hours.
The method according to claim 1, wherein the heat treatment is performed at 50 to 700 ° C., and then the heat treatment in an oxygen-containing gas stream is performed at 250 to 500 ° C. 4. 4. A method for producing acrylic acid by subjecting propane to a gas-phase catalytic oxidation reaction using the catalyst produced by the method according to claim 1. Description: