JPH0259046A - Preparation of molybdenum-containing ammoxidation catalyst - Google Patents

Abstract

PURPOSE:To prepare a catalyst imparting an ammoxidation product in good yield by adjusting the pH of a solution or slurry containing Fe, Bi or Te and an Mo compound to 7 or more before drying and baking said solution or slurry. CONSTITUTION:The pH of a solution or slurry containing at least one compound selected from Fe-, Bi- and Te-compounds and an Mo compound is adjusted to 7 or more and subsequently dried and baked to prepare a molybdenum- containing ammoxidation catalyst. The aforementioned solution or slurry containing catalytic components adjusted to pH7 or more is heat-treated at 50-120 deg.C and, thereafter, the pH thereof is pref. adjusted to 7 or less before drying and baking. The obtained catalyst reduces the combustibility of ammonia in supplied gas at the time of the ammoxidation of an org. compound and has capacity obtaining an ammoxidation product in good yield without adding water.

Description

Detailed Description of the Invention "Industrial Application Field" The present invention relates to a method for producing a molybdenum-containing catalyst used for gas-phase catalytic ammoxidation of organic compounds, and more particularly, it relates to a method for producing a molybdenum-containing catalyst used for gas-phase catalytic ammoxidation of organic compounds, and more particularly, it relates to a method for producing a molybdenum-containing catalyst for use in gas-phase catalytic ammoxidation of organic compounds. This invention relates to a method for producing an ammoxidation catalyst for an organic compound containing one type of element and molybdenum as essential components.

"Prior Art" Many molybdenum-based catalysts are known as ammoxidation catalysts for organic compounds. For example,
No. 5870 discloses P, Mo, Bi catalysts,
Publication No. 17967 includes P and Mo.

Fe, Bi catalyst, M
o, Te catalyst, M in Japanese Patent Publication No. 39-10111
o, Bi, Sb based catalyst, Japanese Patent Publication No. 42-7774, Mo, Bi, Pb based catalyst, JP 50-6419.
MO2Bi is listed in Publication No. 1.

Cr-based catalysts and the like are disclosed. Improvement studies are also being conducted on these catalysts with the aim of further improving their activity. However, in reactions using these molybdenum-based catalysts, the desired ammoxidation product is usually obtained by adding water or excess ammonia to the reaction system, but when water is not added or ammonia When the amount of is decreased, the yield of the desired product decreases. For this improvement, JP-A-55-13187, JP-A-55-
Japanese Patent Publication No. 47-47 and Japanese Patent Publication No. 60-29536 disclose a method of forming various types of warbodies in advance and then combining them with other elements, and Japanese Patent Publication No. 61-58462 discloses a method of adding precious metals. has been done.

However, these methods are unfavorable for producing industrial catalysts, as they require complicated manufacturing methods and require the use of expensive catalyst components.

"Problems to be Solved by the Present Invention" The present invention has been made in view of the above-mentioned problems of the prior art, and its purpose is to solve the problems in the feed gas when ammoxidizing organic compounds. It is an object of the present invention to provide a method for producing a molybdenum-containing catalyst by a simple means, which has low ammonia combustibility and has the ability to provide an ammoxidation product in good yield without the addition of water or the like.

"Another Means to Solve the Problem" In order to achieve the above object, the method for producing a molybdenum-containing ammoxidation catalyst according to the present invention includes (A) at least one element selected from the group consisting of iron, bismuth, and tellurium; B) In a method for producing an oxide catalyst containing molybdenum as an essential component, p of a solution or slurry containing a raw material for component (A) such as iron and a molybdenum compound.
The solution or slurry is then dried and fired.

The catalyst manufacturing technology of the present invention is applicable to many molybdenum-containing ammoxidation catalysts. The composition of the catalyst can be shown by the following empirical formula.

MOaCc D a E * F r O9 (wherein C is at least one element selected from the group consisting of Fe, Bi and Te, D is Ni, Go, Mg, Cr, Mn, Cu, Zn, G
a, G e, Cd, I n, S n, s b, V, W
, Re, P b, Ru, Rh, Pd, os, Ir, P m, Th, U, La, Ce, P r, N d, S m, E
u, G d, A 1. At least one element selected from the group consisting of T i , T a , N b and Z, E is at least one element selected from the group consisting of P and B, F is Li, Na, Rh, At least one element selected from the group consisting of Cs, Ca, Sr, Ba and T1, 0 is oxygen, subscripts a, b, c, dXe, f and g indicate the atomic ratio, a = 8 ~ When 12, c=0.5~20 (preferably 0.5~15)
d・0~25 (preferably 0~23) e=o ~
5 (preferably O to 3) f = 0 to 5 (preferably 0 to 3) and C-indicates the number corresponding to the oxide formed by the combination of the above components) Optional components other than molybdenum and C component , can be appropriately selected and added in order to adjust the selectivity of the reaction product, the reaction rate, the physical properties of the catalyst, etc.

The starting materials for each component constituting the present catalyst can be selected from among many types such as oxides, hydroxides, chlorides, and nitrates of each element.

For example, as raw materials for the molybdenum component, molybdenum oxides such as molybdenum dioxide, molybdic acid, molybdic acid such as ammonium baramolybdate, ammonium metamolybdate, or its salts, molybdenum such as phosphomolybdic acid, and silicomolybdic acid are used. A heteropolyacid containing , or a salt thereof is used.

Ferrous oxide, ferric oxide, triferric tetroxide, iron nitrate, iron chloride, and iron hydroxide can be used as raw materials for the iron component, and metallic iron can also be used by dissolving it in heated nitric acid. good.

As raw materials for the bismuth component, bismuth salts such as bismuth nitrate and bismuth sulfate, bismuth dioxide, and nitric oxides of metal bismuth are used.

As raw materials for the tellurium component, telluric acid, tellurite acid, tellurium dioxide, tellurium trioxide, metallic tellurium dissolved in nitric acid, and the like are used.

When the elements represented by the above-mentioned empirical formulas, E, F, etc. are included as optional components in the catalyst, these optional components can be used as starting materials for the catalyst in the form of oxides, hydroxides, chlorides, nitrates, or other compounds. used for.

According to the present invention, the solution or slurry (hereinafter simply referred to as slurry, etc.) containing the raw material of component (8) such as iron and a molybdenum compound has its pl+ adjusted to a range exceeding 7, and After that, the desired catalyst can be obtained by drying and then calcination.

It is desirable that the slurry etc. be highly dispersed and homogenized. If the pH is lower than 7, the slurry etc. may have a high viscosity or become gel-like, making it difficult to stir the slurry etc., not only making it impossible to obtain a uniform slurry etc., but also making it difficult to obtain the final product. Since the performance of the catalyst is high in ammonia and combustibility, and the yield of the desired product is low, it is preferable to adjust the pH of the slurry, etc. before drying to a range exceeding 7.

In the method of the present invention, heat treatment of the slurry, etc. is not necessarily necessary, but after adjusting the pH of the slurry, etc. to a range exceeding 7, heat treatment in the temperature range of 50 ° C to 120 ° C. This is desirable in terms of stabilizing the properties and further improving the performance of the ultimately obtained catalyst.

In this case, the heating time is preferably at least 10 minutes at the set temperature. When the pH of the slurry, etc. is 7 or less, a catalyst produced without performing heat treatment and then adjusting the pH of the slurry, etc. to a range exceeding 7 has poor performance.

In addition, in the method of the present invention, the pH of the slurry etc. is adjusted to 7.
After adjusting the pH of the slurry to a range exceeding 120°C, heat treatment is performed at a temperature of 50°C to 120°C, and then the pH of the slurry, etc. is adjusted to 7 or less, which improves the physical properties of the final catalyst, especially the strength. Ru.

The slurry etc. thus obtained are then dried. Dry product is 400℃~800℃1 preferably 500℃~
The catalyst of the present invention can be obtained by calcining at a temperature of 750°C for 1 to 50 hours.

The catalyst exhibits excellent activity without a support, but may also be combined with a suitable support. That is, the catalyst can be prepared eight times so as to contain about 20% to 90% of the total active ingredient. As the solid material, silica, alumina, zirconia, silica-alumina, silicon carbide, alundum, and inorganic silicates can be used.

The size and shape of the catalyst are not particularly limited and may be formed into any shape and size such as pellets, tablets, spheres, granules, and powders depending on the usage conditions.

The catalyst produced by the method of the present invention can be used in the ammoxidation reaction of organic compounds. Examples of organic compounds include propylene, isobutyne, methanol, ethanol, tert-butanol, methyl tert-butyl ether, and the corresponding nitriles can be obtained in high yields. In particular, favorable results can be obtained by applying the method to ammoxidation reactions of propylene, isobutyne, and tertiary-butanol.

The catalyst of the present invention can be used in fixed or fluidized beds. The reaction is carried out by supplying a raw material organic compound, ammonia and oxygen to a reactor filled with the catalyst of the present invention. Air is preferably used as the oxygen source for economical reasons. The air may be suitably enriched with oxygen.

Although the molar ratio of oxygen in the raw material fed to the reactor/raw organic compound is in the range of about 1 to about 4, the catalyst produced by the method of the present invention has a high selectivity for ammoxidation products, and has a high selectivity for ammonia oxidation products. Since the utilization rate is high, the molar ratio is relatively low, about 1.
5, to about 2.5. Furthermore, although the molar ratio of ammonia/raw material organic compound in the raw material fed to the reactor can be increased or decreased within the range of about 0.8 to about 3, the catalyst produced by the method of the present invention has a high combustion rate of ammonia. Because of the low molar ratio, sufficiently good yields of the desired product can be obtained at relatively low molar ratios, in the range of about 0.9 to about 1.3.

Further, it is possible to supply an inert gas such as air or water vapor as necessary.

The reaction temperature ranges from about 380"C1 to about 500°C,
Particularly preferred is a temperature range of about 400°C to about 480°C.

The reaction pressure ranges from around normal pressure to approximately 3 Kg/cm G
A range of is appropriate. Appropriate apparent contact times range from about 1 to about 20 seconds.

Hereinafter, the structure and effects of the present invention will be specifically illustrated by examples, but the present invention is not limited only to these examples.

In addition, in this specification, the ammoxidation product yield, the conversion rate of the raw material organic compound, and the ammonia combustion rate are defined by the following formula.

Ammoxidation product yield (χ) Carbon weight of supplied raw material organic compound Conversion rate of raw material organic compound (χ) Carbon weight of supplied raw material organic compound Ammonia combustion rate (χ) Nitrogen weight resistance of supplied ammonia Abrasion test A test known as a test method for fluid catalytic cracking catalysts.
Test Method ForSyn Cracking Catalysts, (Test Method ForSyn
thetic cracking catalysts
) Published by American Cyanamid Company 6/
It was carried out according to the method described in 31-4m-1157. Wear loss (X) was determined by the following formula.

Wear loss (%): R=BX100/ (C-A)
However, A = O ~ Weight of catalyst lost by abrasion in 5 hours B = 5
The weight of the catalyst that lost one member due to abrasion in ~20 hours C-weight of the catalyst used in the test This test was conducted with C-C-50. The R value becomes small.

Examples 1-4 to 1-3 Experimental formula is MO16B++, oFez, oNi*, 5Sb
lsPo, iKo, 40v+, t(SiO□),. A catalyst was prepared using the following method.

Dissolve 3.92g of potassium nitrate in 20In1 of water,
Added to 45g of 20% silica sol. Add 171.0 g of ammonium paramolybdate to this solution while stirring.
d was dissolved in water and added. Next, antimony tetroxide powder 2
25.6g, 186.8g of nickel nitrate in 190dl of water
A solution of 79.8 g of iron nitrate dissolved in 80 m2 of water, 47.9 g of bismuth nitrate dissolved in lO% nitric acid 48
A solution dissolved in d and 2.23 g of an 85% phosphoric acid aqueous solution were sequentially added. 15% ammonia water was added to this slurry while stirring to adjust the pH to 8.

The slurry was heated to an inlet temperature of 320 in a rotating disk type spray dryer.
The temperature was controlled at 160°C for spray drying. The fine particles thus obtained were heat-treated at 250°C, further calcined at 400°C for 2.5 hours, and finally
It was baked at 20°C for 3 hours.

The abrasion loss R value of this catalyst was 5.1%.

Example 2 A catalyst having the same composition as in Example 1 was produced in the same manner as in Example 1, except that the slurry adjusted to pH 8 was heated under reflux at 100° C. for 2 hours. The abrasion loss R value of this catalyst is 6.
It was 3%.

Example 3 A catalyst with the same composition was produced in the same manner as in Example 1, except that a slurry adjusted to pl (8) was heat treated at 100°C under reflux for 2 hours, and then the pH of the slurry was adjusted to 4. The abrasion loss R value of this catalyst was 3.2%.

Example 4 The experimental formula is Mo+ oBiz, slew, o old s, 5
A catalyst having SbsKo, xoq*, 5s(SiO□) 66 was produced by the following preparation method.

Dissolve 2.32g of potassium nitrate in water 23-
g of 20% silica sol. To this liquid, 202.5 g of ammonium paramolybdate dissolved in 610 d of water was added under stirring. Next, antimony tetroxide powder 89.1
g, a solution of 187.2 g of nickel nitrate dissolved in 190 d of water, a solution of 94.6 g of iron nitrate dissolved in 95 m2 of water, a solution of 141.9 g of bismuth nitrate dissolved in 10% nitric acid 14 (ltl)
! The solution dissolved in the solution was added sequentially. Next, 10% nitric acid was added to this slurry while stirring to adjust the pH to 10. Spray drying and calcination were performed according to the method of Example 1, and the calcination was performed at 600°C.

Example 5 Experimental force 'Mo1Ji+, 5Fe+, sNi*,
@P1.6K11. tOax, +(SiOz) 6
A catalyst having a particle size of 0 was produced by the following preparation method.

Dissolve 2.68 g of potassium nitrate in 25% of water,
Added to 7 g of 20% silica sol. Add 233.8 g of ammonium paramolybdate to this solution while stirring and add 700 g of ammonium paramolybdate.
d was dissolved in water and added. Next, nickel nitrate 235.
A solution of 7 g dissolved in 235 d of water, 81.9 g of iron nitrate
solution of Bismuth nitrate in 80 d of water, 98.3 g of bismuth nitrate
10% nitric acid 100mj! and 15.3 g of an 85% phosphoric acid aqueous solution were sequentially added thereto. 15% ammonia water was added to this slurry while stirring to adjust the pH to 12.

Spray drying and calcination were carried out according to the method of Example 1, and 58
It was fired at 0°C.

Examples 6 to 8 Table 1 was prepared in the same manner as in Example 1 except that lead nitrate was used as the raw material for the lead component, telluric acid was used as the raw material for the tellurium component, and the respective aqueous solutions were added after ammonium paramolybdate. Catalysts having the compositions shown in Examples 6 to 8 were produced.

Examples 9 to 11 Using chromium nitrate as the raw material for the chromium component, cobalt nitrate as the raw material for the cobalt component, and magnesium nitrate as raw material #4 for the magnesium component, each aqueous solution was added next to ammonium paramolybdate, and the pH of the slurry was adjusted.
Catalysts having the compositions shown in Examples 9 to 11 in Table 1 were produced in the same manner as in Example 2, except that 9.5 was used.

Examples 12 to 14 Using zinc nitrate as a raw material for the zinc component, manganese nitrate as a raw material for the manganese component, and lanthanum nitrate as a raw material for the lanthanum component, each aqueous solution was added next to ammonium paramolybdate, and the pH of the slurry was adjusted to 8. Example 12 in Table 2 was prepared in the same manner as in Example 2 except that .5 was used.
Catalysts having the compositions shown in ~14 were produced.

Examples 15 to 17 Cerium nitrate was used as a raw material for the cerium component, parathane, ammonium gestate, and
Example 15 in Table 2 was prepared in the same manner as in Example 1 except that ammonium metavanadate was used as a raw material for the vanadium component and added next to ammonium paramolybdate, and the pl of the slurry was adjusted to 8.5. Catalysts having the compositions shown in ~17 were produced.

Examples 18-22 Cesium nitrate as the raw material for the cesium component, calcium nitrate as the raw material for the calcium component, orthoboric acid as the raw material for the boron component, nitric acid of a tin metal as raw material 4 for the tin component, Q7fl liquid, as the raw material for the palladium component Using palladium nitrate, each was added next to ammonium paramolybdate, and the pH of the slurry was adjusted to 9.5 before heat treatment.
Catalysts having the compositions shown in Examples 18 to 22 in Table 2 were produced in the same manner as in Example 3, except that the catalysts were adjusted to 2 and 2 after the heat treatment.

Comparative Examples 1-1 to 1-3 Catalysts with the same composition were produced in the same manner as in Example 11, except that the pH of the slurry containing the catalyst raw materials was adjusted to 2 with 15% aqueous ammonia.

Comparative Example 2 A catalyst with the same composition was produced in the same manner as in Example 1, except that the pH of the slurry containing the catalyst raw materials was adjusted to 5 by adding 15% ammonia water.

Comparative Example 3 The pH of the slurry before and after heat treatment was 10%
A catalyst with the same composition was produced in the same manner as in Example 2, except that the concentration was adjusted to 2.0 with nitric acid.

Comparative Example 4 The pH of the slurry was 2 before heat treatment and 5 after heat treatment.
A catalyst having the same composition as that of Example 3 was produced by the same method as in Example 3, except that each catalyst was prepared with 15% ammonia water.

Comparative Examples 5 to 7 Same as Example 1 except that the pH of the slurry containing the catalyst raw materials was adjusted to 2 by adding 15% aqueous ammonia.
Catalysts having compositions corresponding to Examples 6 to 8 were produced using the iI production method.

Comparative Example 8 ~ IO The pH of the slurry before and after heat treatment was set to 15
Example 1 except that % ammonia water was added to prepare 3.
Catalysts with compositions corresponding to 0.11 and 14 were produced.

Comparative Examples 11-12 The pH of the slurry before and after heat treatment was 15
Example 1 except that % ammonia water was added and adjusted to 2.
Catalysts with compositions corresponding to Nos. 6 and 20 were produced.

The following activity tests were conducted on the catalysts of Examples 1 to 22 and Comparative Examples 1 to 12.

Activity test (propylene ammoxidation) The spray-dried and finally calcined catalyst was placed in a tube with an inner diameter of 25 mmφ and a height of 4
A 0C11 fluidized bed reactor was filled with the mixture for a predetermined contact time and maintained at a predetermined reaction temperature. In this reactor, the molar ratio of propylene:ammonia:oxygen is 1.
: ], I ~ 1.3 : 6 per hour of a mixture of propylene, ammonia, and air with a ratio of 1.95
．． 51 (NTP exchange'!:f,) was supplied. The reaction pressure is normal pressure.

However, the activity tests in Example 1 and Comparative Example 1 were conducted with the propylene:ammonia ratio changed to 1:1.3, 1:1.2, and 1: ], 1, respectively.
-2, and 1-3. In other examples, activity tests were conducted with the propylene:ammonia ratio fixed at 1:1.2.

The reaction conditions and activity test results are shown in Tables 1-3.

Example 23 Experimental force 'MO+oB! e, 5Ni1.5Sb3.5
Po, tsK+, o05+, 9(SiOz)b.

A catalyst was prepared using the following method.

Dissolve 10.4 g of potassium nitrate in 100 m of water,
Added to 55g of 20% silica sol. Add 181.6 g of ammonium paramolybdate to this solution while stirring and add 545 m of ammonium paramolybdate.
It was dissolved in fl water and added. Next, 55.9 g of antimony tetroxide powder and 45.8 g of nickel nitrate were added to 45 d of water.
A solution of 432.9g of bismuth nitrate dissolved in 430m2 of 10% nitric acid? After the mixture was dissolved, 8.9 g of an 85% aqueous phosphoric acid solution was sequentially added. Stir this slurry for 15 minutes.
% ammonia water was added to adjust the pH to 9.5.

The slurry was heated to an inlet temperature of 320 in a rotating disk type spray dryer.
The temperature was controlled at 160°C for spray drying. The dried catalyst was heat treated at 250"C and further heated at 40"C.
The catalyst was calcined at 0°C for 2.5 hours, and then the catalyst was neutralized using a crusher.
It was molded into a cylindrical shape of 2 trm x 2 anφ. This catalyst was finally calcined at 600°C.

Example 24 A catalyst having the composition shown in Example 24 in Table 4 was produced using the same preparation method as in Example 23.

Examples 25 to 26 Catalysts having the compositions shown in Examples 25 to 26 in Table 4 were produced using the same preparation method as in Example 23. However, the pH of the slurry
After adjustment, heat treatment was performed. .

Example 27 A catalyst having the composition shown in Example 27 in Table 4 was produced in the same manner as in Example 23. However, slurry p) II! After adjustment, heat treatment and pHtm adjustment were performed again.

Comparative Example 13 A catalyst with the same composition was produced in the same manner as in Example 23, except that the pH of the slurry containing the catalyst raw materials was adjusted to 3 by adding 15% aqueous ammonia.

Comparative Example 14 A catalyst with the same composition was produced in the same manner as in Example 24, except that the pH of the slurry containing the catalyst raw materials was adjusted to 2 by adding 15% aqueous ammonia.

Comparative Example 15 A catalyst with the same composition was produced in the same manner as in Example 25, except that the pH of the slurry before heat treatment was adjusted to 0.8 with 10% nitric acid.

Comparative Example 16 A catalyst with the same composition was produced in the same manner as in Example 27, except that the pH of the slurry before heat treatment was adjusted to 2 by adding 15% aqueous ammonia.

Activity tests were conducted on the catalysts of Examples 23 to 27 and Comparative Examples 13 to 16 as follows.

Activity test (ammo-oxidation of isobutyne) The catalyst was dried, wetted, molded into a cylindrical shape of 2ffll, 11 x 2 plates, φ, and finally calcined at 600°C. The mold reactor was filled. This was heated in a molten salt bath consisting of an isochemical compound of sodium nitrite and potassium nitrate until the reaction temperature reached 390°C.
It was maintained at ℃. Isobutine in this reactor:
The ammonia:oxygen ratio is 1: ], 2:2.3
A mixed gas of isobutyne, ammonia, and air was supplied per hour (in terms of NTP). The reaction pressure is normal pressure.

The reaction conditions and activity test results are shown in Tables 4 and 5.

"Effects of the Invention According to the present invention, a molybdenum-containing ammoxidation catalyst can be produced by slow means without the need for complicated operations to form various types of molybdate in advance, and this catalyst Due to its low flammability, it provides the desired ammoxidation product in high yield even at a low ammonia/raw material battering compound molar ratio when ammoxidizing organic compounds.

Claims (1)

[Claims] 1) At least one element selected from the group consisting of (A) iron, bismuth and tellurium used for ammoxidation and (B)
) In a method for producing an oxide catalyst containing molybdenum as an essential component, the pH of a solution or slurry containing a raw material for component (A) such as iron and a molybdenum compound is set to 7.
1. A method for producing a molybdenum-containing ammoxidation catalyst, which comprises adjusting the molybdenum-containing ammoxidation catalyst to a range exceeding the above range, and then drying and calcining this solution or slurry. 2) A molybdenum-containing solution or slurry containing a catalyst component whose pH is adjusted to a range of more than 7 according to claim 1, which is heat-treated at a temperature in the range of 50°C to 120°C, and then dried and calcined. Production method of ammoxidation catalyst. 3) A solution or slurry containing the catalyst component whose pH has been adjusted to a pH higher than 7 according to claim 1 is heat treated at a temperature of 50°C to 120°C, the pH is adjusted to 7 or less, and the solution or slurry is dried and calcined. A method for producing a molybdenum-containing ammoxidation catalyst. 4) The composition of the oxide catalyst is expressed by the following empirical formula Mo_aC_cD_dE_eF_fO_g (wherein C is at least one element selected from the group consisting of Fe, Bi, and Te, and D is Ni, Co, Mg, Cr, Mn, Cu, and Zr. , Ga
, Ge, Cd, In, Sn, Sb, V, W, Re, Pb
, Ru, Rh, Pd, Os, Ir, Pt, Th, U, L
a, Ce, Pr, Nd, Sm, Eu, Gd, Al, Ti
, at least one element selected from the group consisting of Ta, Nb and Zr, E is at least one element selected from the group consisting of P and B, F is Li, Na, K, Rb, Cs, Ca, Sr , at least one element selected from the group consisting of Ba and Ti, O is oxygen, subscripts a, b, c, d, e, f and g represent atomic ratios, a=8-12 c=0 .5 to 20 d = 0 to 25 e = 0 to 5 f = 0 to 5 and g = a number corresponding to the oxide formed by combining the above components. 3. The method for producing a molybdenum-containing ammoxidation catalyst according to 3.