JPS58131136A - Catalyst composition - Google Patents

Abstract

PURPOSE:To obtain a catalyst having high activity, high selectivity and long life, by constituting a catalyst forming acrylonitrile from C3H6, NH3 and O2 from a catalyst containing Mo, Bi, Pb, Sb, Cr, O or, further, W, Fe in a specific ratio. CONSTITUTION:A catalyst composition is shown by formula (wherein a-h show atomic numbers of each components, when a+b+c is equal to 12, (b) is 0-7, (c) is 0.4-7, (d) is 2-12, e/a is 0.1/22-25/22, (f) is 0-3/22, g/a is above 0-3/22, (h) is an atomic number required in satisfying the valency of each component). This catalyst shows excellent catalytic effect in reaction for forming acrylonitrile by contacting C3H6, NH3 and O2 or an O2-containing gas in a gas phase. That is, even under a condition of high C3H6 reaction efficiency, acrylonitrile can be prepared at high yield and the life of the catalyst is also long.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to catalyst compositions. For details, refer to the reaction of bringing olefins, ammonia, and oxygen or oxygen-containing gas into contact in the gas phase to produce IJ, especially by bringing propylene, ammonia, and oxygen or oxygen-containing gas into contact in the gas phase. The present invention relates to a composition that exhibits an excellent catalytic effect in the reaction of producing acrylonitrile. Various catalyst systems have been proposed as catalysts for so-called ammoxidation, in which acrylonitrile is produced by contacting propylene, ammonia, and oxygen or an oxygen-containing gas in the gas phase, but none have been used in industrial practice. There are very few catalysts.

Among these, noteworthy catalysts include oxide catalysts whose basic composition is molybdenum and bismuth, and which further includes iron and phosphorus. Since then, various improvement methods have been proposed for this type of catalyst, and a representative example is a rubbing oxide catalyst. However, these catalysts still do not sufficiently suppress side reactions, and when the reaction rate of propylene is increased, the selectivity decreases, making it difficult to obtain a sufficiently high yield of acrylonitrile. For industrial use, it is important that the catalyst has a long life. Therefore, the present inventors conducted research to develop a catalyst with high activity and high selectivity, that is, a catalyst that can produce acrylonitrile with high selectivity even when reacting propylene at high reaction rate, and has a long life. As a result, if you use a catalyst containing molybdenum, bismuth, lead, antimony, chromium and oxygen in a specific composition range, or a catalyst in which a specific amount of tungsten and/or iron is added to the above elements, you can replace the conventional molybdenum-bismuth catalyst. The present invention was achieved by discovering that acrylonitrile can be produced in high yield even under conditions of high propylene reaction rate, and that the life of the catalyst can be extended.

The catalyst composition of the present invention has the composition formula (Mo)a (W)b (
Bi)c(pb)a(Sb)e(Fe)f(Or)g(
0)h (However, a, b, c, d.

θ, f, g, h are molybdenum, tungsten,
When the number of atoms of bismuth, lead, antimony, iron, chromium, and oxygen is expressed as a 10b −/λ, O≦b≦7, 0.
4t≦C≦7, 2≦d≦72, '-'//2.2≦θ/
a≦2V-1θ≦f/, ≦3/2, 0<g/a≦
3h, where h represents the number of oxygen atoms necessary to satisfy the valences of each of the above components. ).

In the catalyst composition of the present invention, the number of atoms of each component element particularly suitable for improving the IJ yield is a+
'b-/, when 2, 0≦b≦evening, evening, 0.6<:C
≦B, ko, ni≦d≦//,'/xa≦e/a≦/shi discussion,
θ≦f/a≦−7//2.2 and θ, 0! /22≦g
/a≦=2/22 and Al. γ? t-4tkt-! ALi
t7, θ, θ woman ≦ almost ≦ 1 to 9 seconds.

The catalyst composition of the present invention may be molded in an IT manner without using a carrier, or a molded product may be obtained using a carrier such as silica, alumina, titania, silicon carbide, or the like. The size and shape of the catalyst particles are not particularly limited, and may be in the form of pellets, tablets, or
It can be molded into any shape and size, such as spherical or granular.

As the molybdenum compound used for catalyst preparation, molybdenum oxides such as molybdenum trioxide, molybdic acid or its salts, and phosphomolybdic acid or its equivalent are used, but molybdic acid such as ammonium paramolybdate is preferably used. Salt is used.

As the tungsten compound, tungsten oxide such as tungsten trioxide, tungstic acid or condensed acid thereof, or a salt thereof, phosphotungstic acid or a salt thereof, etc. are used.

As the bismuth compound, bismuth salts such as bismuth nitrate and bismuth sulfate, and various oxides or hydroxides of bismuth are used.

As lead compounds, lead salts such as lead nitrate and lead sulfate, and various lead oxides or hydroxides are used.

As the antimony compound, oxides such as antimony trioxide, chlorides such as antimony trioxide, antimony metal, etc. are used.

As the iron compound, iron salts such as iron nitrate and iron sulfate, and various iron oxides or hydroxides are used.

As the chromium compound, chromium salts such as chromium nitrate, chromium sulfate, and ammonium dichromate, and various chromium oxides or hydroxides are used.

To produce a catalyst using these raw materials, a compound of each component element is dissolved or suspended in water, and depending on the case, a sol of a carrier component such as silica sol or alumina sol or a carrier powder such as titania powder is added. After suspending it to make a uniform slurry or aqueous solution, it may be fired.

When shaping a catalyst by spray drying, a catalyst with excellent impact resistance can be obtained by adjusting the pH of the spray raw material slurry to /-4 and then performing spray drying.

When ammonium paramolybdate and ammonium paratungstate are used as the dimolybdenum compound and tungsten compound, respectively, in the production of the catalyst, ammonia or the like is added to the aqueous solution containing these salts in order to increase the solubility of Mrfe in water. Preferably, a solubility promoter is added. When bismuth nitrate or bismuth sulfate is used as the bismuth compound, it is preferable to use an acidic nitric acid aqueous solution or a sulfuric acid acidic aqueous solution, respectively. When using antimony trioxide as the ground antimony compound, it may be used by dissolving it in an organic aqueous solution such as tartaric acid, but when using antimony trioxide powder, the slurry containing each catalyst component must be uniformly stirred. It is preferable to adjust the pH to 7 or less and heat-treat to θC or higher for 7 to 2 hours.

In this case, an iron compound can be added to the slurry in the heat-treated layer, if desired.

The firing temperature and firing time of the catalyst forming layer are not particularly limited, but the firing temperature is usually between tioo and θθC1.
Preferably, the temperature is selected within the range of θθ to θC, and the firing is performed for a period of time between evening and evening.

The reaction in which the catalyst composition of the present invention is used is acrylonitrile)
To explain the case of producing IJL, acrylonitrile is produced by contacting propylene, ammonia, and oxygen or an oxygen-containing gas in the gas phase in the presence of a queen's catalyst.

The raw material gas propylene does not necessarily have to be of high purity, and may contain a gas substantially inert to the reaction, for example, a saturated hydrocarbon such as propane.

Air is used industrially as the oxygen-containing gas. The molar ratio of oxygen to propylene to be supplied is preferably 1 - 1 times, preferably in the range of 8 to 1,000 molar. The ratio of ammonia to propylene is the molar ratio θ,! The range is preferably from 9 to i, s, preferably θ, 9 to i, s. The reaction is usually carried out under normal pressure, but may be carried out under reduced pressure or increased pressure if necessary. The reaction temperature is usually 3≦0~
The angle is OC, preferably 0θ to 5θθC. In addition, the space velocity of the raw material gas is in the range of /θO~3θθθhr”,
Preferably, it can be appropriately selected from the range of 200 to 2θ00 hr-''.

The catalyst composition of the present invention can be used in a fixed bed or fluidized bed. Either method can be used.

As explained in detail above, according to the ammoxidation of propylene using the catalyst composition of the present invention, acrylonitrile is produced with a high selectivity even when the reaction rate of the raw material gas is increased. can be manufactured.

Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. In this specification, the reaction rate, selectivity, and acrylonitrile yield are defined by the following formula.

Example/ Ammonium paratungstate (NH4) I. W, 2
O.

・RiH, OC, θ3q, 2y wo/34-t 91% ammonia water d To a solution dissolved in d, -〇 weight ratio silica sol/6. /li2, followed by lead nitrate"b (NO
3) A solution of 23.0309 dissolved in 1 nl of water, anthonium paramolybdate (NH4) 6MO70
24 KH20, 2, 2-2 evening 1! Weight% ammonia water/solution dissolved in ml and bismuth nitrate/
, / to 70% weight ratio nitric acid aqueous solution 1. and ml of the solution was added. Next, commercially available antimony trioxide 81
)20. Powder 3.9 t 3 S' water t g, +2 m
l, , 2 r heavy fJ % ammonia water λ, ♂θm
, l and tartaric acid! , 3 F and heated to dissolve it, measure the ///θ of the obtained liquid, add it to the above slurry, and then add ferric nitrate Fe(No, ) 369H2
Add a solution of 0θ, //jr't dissolved in water 3- and a solution of chromium nitrate 0r(No,)3・wama○ θ, /371 dissolved in 3ml of water, and add a 70% by weight aqueous solution. The mixture was adjusted to pH J. 2, and heated on a hot plate with stirring to avoid generation of No. 2 to dryness.

The obtained solid material was formed into a tablet with a diameter of 6M and a thickness of 3 mm, calcined for 2 hours at 7θθC under air circulation, and then crushed to obtain a granular catalyst with a mesh size of /2 to 2'. The composition of the catalyst thus obtained was λ'O1+, 86 WO
, 14Bi2. +16”bll, 61 Sb2.21
Fe (147Cro, 320fi2.2, ratio of silica as a carrier and catalyst component θ: 60 (overtone ratio)
Met.

This catalyst/ml was filled into a heated glass reactor with a molar ratio of propylene:ammonia:air-/:Ha2:/θ, and a mixed gas with a space velocity of 50θhr” was supplied to the reaction tube. The reaction was carried out at 96.theta.C. As a result, the propylene reaction rate was 9, and the acrylonitrile selectivity was J'7!;, 2% (acrylonitrile yield was ! evening, θ).

Examples 2 to 6 Catalysts having the compositions shown in Table 1 were prepared in the same manner as in Example 1, and the reactions were carried out in the same manner as in Example 1 at the reaction temperatures shown in the table. The results are also shown in Table 7.

Comparison 1 Comparative Example/Example/Ferric Nitrate Fe (No3), -? Omitting the addition of H20, chromium nitrate 0r (No3), 9H70
The same experiment as in Example 1 was repeated except that the amount added was increased.

The catalyst composition and reaction results are shown in Table 2.

Comparative Example The same experiment as in Example 3 was repeated except that antimony was not used in Example 3.

The catalyst composition and reaction results are shown in the table.

Example 7 Same experiment as Example/ except that the addition of ferric nitrate Fe(No3)3.9H20 was omitted and the amount of chromium nitrate 0r(No3)3.9H20 was increased. repeated.

The catalyst composition and reaction results are shown in Table-/.

A fluidized catalyst having the same composition as that of the example and the actual axis was prepared as follows. Ammonium paratungstate (N
H4), oW,,04+-! A solution of IF (207FAt f dissolved in 1 wt% ammonia water/lK) was added to 20 weight width silica sol 3.2.37 ky under stirring. Then, commercially available antimony trioxide 5b203 powder 7/θ, 7
f to 2.9 t of water, -25 weight of ammonia water and omi.

and tartaric acid/θ 92 and dissolved by heating, the resulting solution was added to the above slurry under stirring, and then lead nitrate Pb (NOx) 2t and o tky were dissolved in water //, 3t. solution, ammonium paramolybdate (NH4
)6MO□02. *LiH2O, a solution of Kuta Oky dissolved in 5-fold aqueous ammonium nitrate and 1, bismuth nitrate Bi (NO3)3S H2O2, 32 and 1 in lθ weight ratio nitric acid aqueous solution Ω, 70 t. solution, ferric nitrate Fe (No3), -! A solution of PH20, 2F, 2f' dissolved in 2.2 liters of water and chromium nitrate 0r (
nos)s・? Add a solution of H, 0274t, 3f dissolved in water, 2.5m and add 67wt nitric acid.I)
H2, adjustment-]4-. The slurry thus obtained was homogenized using a homogenizer, and spray-dried using a conventional method using a spray device having a rotating disk to form fine particles.Then, the slurry was placed in a rotary firing furnace at a temperature of 670 C1 residence time/min. Continuous firing was carried out to obtain grains with an average particle size of 10 μm.

Next, this catalyst/container θV was packed into a fluidized bed reactor with an inner diameter of 2.5 inches, and a mixed gas of propylene:ammonia:air=/:ha/:/, t, 7 was added to the catalyst at a molar ratio of propylene:ammonia:air=/:ha/:/. The load per unit time is 0.0gJ'
hr-'' (supplied propylene r/hr/Y cat ), and the reaction was carried out at a temperature, lf'o C1 pressure o, and z ky / crl G. Until a steady state was reached. Then, it took about /θθ time.The results are shown in Table 3.

Comparative Example 3 Ammonium paratungstate (NH,). W18
O49! H2O2t/? / Binitrate ammonia water 3.
Commercially available antimony trioxide 81) and 03 powder 35θ2 were added to the solution dissolved in No. 3, while stirring. While stirring vigorously,
Add 20 g to 32.6 g of silica sol, followed by lead nitrate (PI) (No. 3), 6. 29 to 1 water//
, a solution dissolved in 7t, ammonium paramolybdate (NH4), MO? 0.4- <(H, OK, evening O
kp! A solution of binitrate ammonia water dissolved in 1.5't and a solution of bismuthco nitrate, 3-3-2f dissolved in 70% by weight nitric acid aqueous solution 2.7θt were added, and 67
The pH of the slurry was adjusted to λ using M nitric acid.

Next, phosphotungstic acid P20. - Koku Wo, - Guhezata H, 02/Yu, 92 dissolved in water/l and potassium carbonate with 2Co8/3. A solution prepared by dissolving Z. 7 in θOml of water was added to the above slurry, charged into a Mitsuro flask, and heated under reflux at 100°C for 3 hours. Due to the heat treatment, the pH of the slurry increased from 9.2 to θ in the evening, so it was adjusted again to 0.2, then homogenized using a homogenizer, and then mixed using a conventional method using a spraying device with a rotating disk. Spray dried. The obtained microparticles were placed in a rotary firing furnace, heated to a temperature, and continuously fired under the conditions of C1 residence time/minute to obtain spherules with an average particle size of 50 μm. The composition of the thin skin thus obtained is MO+1.2 WO,
8B1.2j Pb8,4 S”1.07 KO,09
"(1,.3049.28), and the ratio of silica as a carrier and the catalyst component was 0:≦θ (gravitational ratio). This catalyst/15θ2 was packed into the same reactor as in the example. The reaction was carried out under the same reaction conditions as in the example.

The results are shown in the table.

Table-3 table Sender: Mitsubishi Chemical Industries, Ltd. Representative Patent Attorney Hase-yo - 7 others 18-

Claims (1)

[Claims] (1) Composition formula % formula % (0) (However, a, b, c, 6., e, f, g, h represent the number of atoms of molybdenum, tungsten, bismuth, lead, antimony, iron, chromium, and oxygen, respectively. Indicate, a + b =
7.2, θ≦b≦7, θ, 4t≦C≦7, ko≦d≦/, 2, θ-'/, 2.2≦Q/a≦2V-1θ
≦f/a≦n, θ<g/a≦'/, 2a, and h indicates the number of atoms necessary to satisfy the valence of each component. ) Propylene, ammonia and oxygen =!
Catalytic composition suitable for producing acrylonitrile from or oxygen-containing gas