JP2001139537A - Method of manufacturing acrylonitrile and/or acrylic acid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture acrylonitrile and/or acrylic acid in a stabilized reaction for a long time by suppressing deterioration of a catalyst in the manufacture of the acrylonitrile and/or acrylic acid by a vapor phase catalytic oxidation of propane. SOLUTION: The concentration of each nickel, copper, zinc and mercury in a gas supplied for the reaction, is set <=0.2 wt.ppm based on element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing acrylonitrile and / or acrylic acid by a gas phase catalytic oxidation reaction of propane. In particular, the present invention relates to a method for performing this reaction with stable results while suppressing catalyst deterioration over a long period of time.

[0002]

2. Description of the Related Art Acrylonitrile and acrylic acid are both important chemicals, and are currently produced exclusively by gas phase catalytic oxidation of propylene. However, since propylene is also in great demand as a raw material such as polypropylene, production of acrylonitrile and acrylic acid from propane, which is cheaper than propylene, has been studied recently. Since propane is less reactive than propylene, research has primarily focused on catalyst development.
At present, catalysts that give acrylonitrile and acrylic acid with quite good performance have been developed.

[0003]

However, in order to industrially produce acrylonitrile or acrylic acid from propane, it is necessary to stably exert its ability for a long time without deteriorating the catalyst. Accordingly, an object of the present invention is to provide a method for producing acrylonitrile or acrylic acid which satisfies such requirements.

[0004]

According to the present invention, at least propane and oxygen are supplied in a gaseous state to a reactor containing a solid catalyst, and acrylonitrile and / or acrylonitrile and / or oxygen are reacted by a gas phase catalytic oxidation reaction of propane. In the production of acrylic acid, nickel in the total gas supplied to the reactor,
Simple substance or compound of copper, zinc, and mercury (however, aperture 5
By limiting the total amount of the catalyst (passed through a 0 μm filter) to 0.2 (weight) ppm or less in terms of element, the catalyst can be prevented from deteriorating with time and the reaction can be performed with a stable performance over a long period of time. Can be made.

[0005]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail. In the present invention, a metal oxide, particularly a composite metal oxide containing a plurality of metals, is used as a catalyst in a gas phase catalytic oxidation reaction of propane. However, it is based on the finding that metals such as nickel, copper, zinc, iron, and mercury and compounds containing these metals in the gas supplied to the reactor poison the catalyst. Although the mechanism of poisoning is unknown, the metal constituting the catalyst and the above-mentioned metal elements in the gas have a chemical affinity, so that the effective active sites of the catalyst are reduced or altered. It is thought to be. Among these metals, copper and mercury have the strongest poisoning effects, and iron has a relatively low poisoning effect. In the supply gas, these metal elements are considered to exist in various forms such as an organometallic compound, a carbonyl compound, a halide, a sulfide, a cyanide, an oxide, and a simple substance. And when it exists in gaseous form such as a carbonyl compound, the poisoning action is considered to be the strongest. However, when it exists in fine particle form, it reacts with the catalyst metal and poisons the catalyst. However, when the particle shape is large, the reactivity with the catalytic metal is reduced, so that the poisoning action is reduced. Therefore, when the above-mentioned metal components are present as a solid in the supply gas, those which cannot pass through a filter having an aperture of 50 μm can be ignored.

In the present invention, the total concentration of nickel, copper, zinc and mercury in the gas supplied to the reactor is set to 0.2 (weight) ppm or less in terms of element. More preferably, the total concentration of these metal components is 0.1 (weight) ppm or less, particularly 0.05 (weight) ppm or less in terms of element.
In a further preferred embodiment of the present invention, the above nickel, copper,
The sum of zinc and mercury plus iron should be within the ranges specified above. Since these metal components in the gas are mainly derived from the raw material propane, if the concentration of these metal components in the gas exceeds the range specified above, propane is purified to reduce its metal content. What is necessary is just to reduce it. For example, depending on the form of the presence of these metal components, by adsorbing propane with an adsorbent capable of adsorbing these metal components, or by extracting propane with a solvent having a high affinity for these metal components, The metal content can be reduced. It is preferable to use propane having a nickel, copper, zinc and mercury concentration of 0.5 ppm by weight or less, especially 0.2 ppm by weight or less, in terms of element. More preferably, those having nickel, copper, zinc, mercury and iron concentrations within the above ranges are used. Quantification of these metal elements in the gas can be performed by any known method such as an atomic absorption method, an absorptiometry, and a fluorescent X-ray method. For example, in the case of the absorption spectrophotometric method, dimethylglyoxime for nickel, dithizone for zinc and mercury, and thiocyanate or 1,10-phenanthroline for iron may be used as a coloring agent. Copper can be quantified with ammonia as an animine complex. The gas to be analyzed is
It is preferable that the metal component is condensed by passing through an adsorption tower filled with an adsorbent or a washing tower containing a solvent to adsorb and absorb a metal element, and then subjected to analysis.

The catalyst used in the gas phase catalytic oxidation reaction of propane in the present invention contains a metal oxide as an active ingredient as described above. Numerous studies have been published on this type of catalyst. For example, as a catalyst for producing acrylonitrile from propane, ammonia and oxygen, a V-Sb-based oxide catalyst (Japanese Patent Application Laid-Open No. 47-33783, Japanese Patent Publication No.
0-23016), V-Sb-W-based oxide catalyst (JP-A-2-261544), V-Sb-Sn-
Cu-Bi-based catalyst and V-Sb-Sn-Cu-Te-based oxide catalyst (JP-A-4-275266), Sb-S
n-based, As-Sn-based, Mo-Sn-based and V-Cr-based oxide catalysts (JP-B-50-28940), Mo-Bi
-Fe-Al-based oxide catalyst (JP-A-3-157356), Mo-Cr-Te-based oxide catalyst (US Pat. No. 5,171,876), Mo-Bi-Cr-based oxide catalyst (JP-A-7-215925), Cr-S
b-W-based oxide catalyst (JP-A-7-157461), Mo-Sb-W-based oxide catalyst (JP-A-7-157)
462), Mo-Bi-Cr-Nb-based oxide catalyst (JP-A-6-116225), Mo-V-Te-based oxide catalyst (JP-A-2-257, JP-A-5-14)
No. 8212 and JP-A-5-208136),
Mo-V-Sb-based oxide catalyst (JP-A-9-157241)
No.). Among them, Mo-V-Te
Based or Mo-V-Sb based oxide catalysts have excellent performance and are preferred catalysts for use in the present invention. Further, as a catalyst for producing acrylic acid from propane and oxygen, Mo-V-Te-based oxides (JP-A-6-279351) are used.
Publication) and Mo-V-Sb-based oxide catalysts
-45664), which are also preferred catalysts for use in the present invention.

A preferred catalyst for use in the present invention is Mo-VX (X = Te, S) containing molybdenum and vanadium and / or at least one of tellurium and antimony.
b) A system oxide catalyst. The catalyst further comprises niobium,
Tantalum, tungsten, titanium, aluminum, zirconium, chromium, manganese, iron, ruthenium, cobalt, rhodium, nickel, palladium, platinum, bismuth, boron, indium, phosphorus, germanium, rare earth elements, alkali metals and alkaline earth metals It may be contained. This catalyst has its atomic composition, ie, M
The atomic ratio R _Mo of molybdenum, vanadium, X and Y to the sum of o, V, X and Y (where X represents tellurium and antimony, and Y represents the above-mentioned element of niobium and below),
R _V , R _X and R _Y are respectively 0.25 <R _MO <0.98 0.003 <R _v <0.5 0.003 <R _x <0.50 ≦ R _Y <0.5 Demonstrates even better catalytic performance at certain times. This catalyst can be prepared by preparing a solution or slurry containing a compound of each element by a conventional method, removing a solvent from the solution or slurry by spray drying or other methods to obtain a solid, and calcining the solid. Further, in a solution or slurry before being subjected to solvent removal, silica, alumina, titania, zirconia, aluminosilicate, which are commonly used in catalyst preparation,
By containing a carrier component such as diatomaceous earth and a binder component such as silica sol and alumina sol, a catalyst containing a carrier and a binder can be obtained. These inert components are usually contained in the final catalyst at a concentration of 1%.
It is preferred that the content be contained so as to be about 90% by weight.

In the production of acrylonitrile or acrylic acid by the gas phase catalytic oxidation reaction of propane according to the present invention, a raw material gas such as propane, oxygen or ammonia is continuously supplied to a reactor containing a catalyst according to a conventional method. And react. As the reaction system, any system such as a fixed bed, a fluidized bed and a moving bed can be used, but a fluidized bed system in which the reaction heat can be easily controlled is preferable. Regardless of whether acrylonitrile or acrylic acid is produced, the reaction temperature is 300 to 490 ° C and the reaction pressure is 0.01 to 1M.
The reaction is preferably performed at Pa and a gas space velocity of about 100 to 10,000 hr ^-1 . Further, the supply ratio of oxygen to propane is preferably about 0.2 to 4 mol times in both acrylonitrile and acrylic acid. In the case of acrylonitrile, 0.1
Ammonia is supplied at about 3 mole times. In both cases of acrylonitrile and acrylic acid, generally, when the reaction rate of propane increases, the selectivity of acrylonitrile and / or acrylic acid decreases. Therefore, when it is desired to produce acrylonitrile or acrylic acid with high selectivity to propane, the reaction is performed so that the reaction rate of propane becomes about 10 to 70%, and unreacted propane is recovered from the reaction product gas. It can be supplied again to the reactor. Further, it is preferable to supply nitrogen, argon, water vapor, carbon dioxide and the like to the reactor in order to facilitate the control of the reaction.

[0010]

The present invention will be described more specifically with reference to the following examples. Preparation of Mo-V-Te-Nb mixed metal oxide catalyst; 5.68 liters of warm water, 1.38 kg of ammonium paramolybdate, 0.275 of ammonium metapanadate
kg and 0.413 kg of telluric acid were added and dissolved. 0.658 kg of a silica sol having a silica content of 20% by weight was added to this aqueous solution, and further, a niobium oxalate aqueous solution (niobium concentration 0.4 Mol / l)
1.02 kg was added. Water was evaporated and removed from the resulting slurry by a conventional method to obtain a solid. This 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 to obtain a catalyst. The metal atom composition of the composite metal oxide which is the active component of this catalyst is Mo ₁ V _0.3 Te _0.16 Nb _0.12 , and the catalyst contains 90% by weight of this composite metal oxide and 10% by weight of silica.
Consists of

Example 1 A fixed bed flow reactor was charged with a mixture of 0.1 g of the catalyst obtained above and 0.4 g of spherical silica particles, and a mixed gas comprising propane, ammonia, oxygen and nitrogen was added thereto. (Molar composition 1: 0.3: 1.5: 1.2) for about 800 h
Supply at a space velocity of r ^-1 , pressure 0.11 MPa, temperature 4
The reaction was carried out at 35 ° C. to produce acrylonitrile. The concentration of the metal component of propane used was 0.023 ppm of nickel (weight ppm, the same applies hereinafter) and 0.0% of copper in terms of elements.
16 ppm, zinc 0.018 ppm, mercury 0.007p
pm, and the iron concentration was 0.001 ppm or less. The concentration in the gas introduced into the reactor was 0.006 ppm for nickel, 0.004 ppm for copper, and 0.0% for zinc.
At 0.05 ppm and 0.002 ppm of mercury, the concentration of iron is 0.1 ppm.
001 ppm or less. The measurement of the metal concentration was performed by the absorption spectrophotometry. Table 1 shows the reaction results at 20 hours and 300 hours after the start of the reaction.

Comparative Example 1 Nickel 0.053 ppm, copper 0.053 ppm, zinc 0.018 ppm, mercury 0.695 ppm, iron 0.00
Acrylonitrile was produced in exactly the same manner as in Example 1 except that propane containing 1 ppm or less was used. The metal concentration in the gas introduced into the reactor is 0.01 ppm nickel, 0.014 ppm copper, 0.005 zinc.
ppm, mercury 0.174 ppm, and iron 0.001 ppm or less. Table 1 shows the reaction results at 20 hours and 300 hours after the start of the reaction.

[0013]

[Table 1]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) // C07B 61/00 300 C07B 61/00 300 F term (reference) 4G069 AA02 AA03 BA02B BB06A BB06B BC01A BC08A BC16A BC18A BC23A BC25A BC26A BC38A BC50A BC51A BC54A BC54B BC55A BC55B BC56A BC58A BC59A BC59B BC60A BC62A BC66A BC67A BC68A BC70A BC71A BC72A BC75A BD03A BD07A BD10A BD10B CB07 CB17 CB76 DA05 BA02 BA07 BA08 BA08 BA08 BA08 BA26 BA30 BA31 BC10 BC11 BC31 BC40 BE30 4H039 CA65 CA70 CL50

Claims (8)

[Claims] 1. Acrylonitrile and / or acryl for producing acrylonitrile and / or acrylic acid by gas phase catalytic oxidation of propane by supplying at least gaseous propane and oxygen to a reactor containing a solid catalyst. In the method for producing an acid, the total amount of nickel, copper, zinc, and mercury simple substance or compound (limited to those that have passed through a filter having an aperture of 50 μm) in all gases supplied to the reactor is calculated as an element. 0.2 (weight) ppm
A method characterized by the following. 2. An acrylonitrile and / or an acryl for producing acrylonitrile and / or acrylic acid by a gas-phase catalytic oxidation reaction of propane by supplying at least gaseous propane and oxygen to a reactor containing a solid catalyst. In the method for producing an acid, the total amount of nickel, copper, zinc, mercury and iron simple substance or compound (limited to those passed through a 50 μm filter) in the total gas supplied to the reactor is determined by 0.2 (weight) pp in conversion
m or less. 3. The method according to claim 1, wherein the solid catalyst is a composite metal oxide containing molybdenum, vanadium and X. X represents at least one element selected from the group consisting of tellurium and antimony. 4. A solid catalyst comprising: molybdenum, vanadium,
3. The method according to claim 1, wherein the composite metal oxide contains X and Y. Here, X is at least one element selected from the group consisting of tellurium and antimony, and Y is niobium, tantalum, tungsten, titanium, aluminum, zirconium, chromium, manganese,
Iron, ruthenium, cobalt, rhodium, nickel, palladium, platinum, bismuth, boron, indium, phosphorus,
It is at least one element selected from the group consisting of germanium, rare earth elements, alkali metals and alkaline earth metals. 5. An atomic ratio R _Mo , R _V , and R _X to the total of molybdenum, vanadium, and _X is 0.25 <R _MO <0.98 0.003 <R _v <0.5 0.003. 4. The method according to claim 3, wherein <R _x <0.5. 6. The respective atomic ratios R _Mo , R _V , R _X and R to the sum of molybdenum, vanadium, X and Y.
5. The method according to claim 4, wherein _Y is 0.25 < _RMO <0.98 0.03 < _Rv <0.5 0.03 < _Rx <0.50 < _RY <0.5. The described method. 7. The reactor is charged with 0.
2 to 4 moles of ammonia, 0.1 to 3 moles of ammonia are supplied,
The reaction is performed at a temperature of 300 to 490 ° C. and a pressure of 0.01 to 1 M.
7. The method according to claim 1, wherein the method is carried out at Pa to produce mainly acrylonitrile. 8. The reactor is charged with 0.2 oxygen to propane.
４4 mole times and the reaction was carried out at a temperature of 300-490 ° C.
The method according to any one of claims 1 to 6, wherein the reaction is performed at a pressure of 0.01 to 1 MPa to generate acrylic acid.