JP2903317B2 - Preparation of molybdenum-containing ammoxidation catalyst - Google Patents

Description

The present invention relates to a method for producing a molybdenum-containing catalyst for use in the gas phase catalytic ammoxidation of organic compounds, and more particularly to at least one selected from the group consisting of iron, bismuth and tellurium. The present invention relates to a method for producing an ammoxidation catalyst for an organic compound containing a kind of element and molybdenum as essential components.

"Prior art" Many catalysts based on molybdenum are known as ammoxidation catalysts for organic compounds. For example,
No. 5870, P, Mo, Bi, catalyst, JP-B-38-17967, P, Mo, Fe, Bi catalyst, JP-B-37-11008, Mo, Te catalyst, JP-B-39-10111 No., Mo, B
i, Sb-based catalysts, Japanese Patent Publication No. Sho 42-7774 discloses Mo, Bi, Pb-based catalysts, and JP-A-50-64191 discloses Mo, Bi, Cr-based catalysts. Improvement studies have been conducted on these catalysts for the purpose of further improving the activity. However, in the reactions using these molybdenum-based catalysts, the desired ammoxidation product is usually obtained by adding water or an excess of ammonia to the reaction system. When the amount of is reduced, the yield of the target product decreases. For this improvement, JP-A-55-13187, JP-A-55-47144 and JP-B-60-29536 disclose a method in which various molybdates are formed in advance and then combined with other elements. Tokiko Sho 61-58
No. 462 discloses a method of adding a noble metal.

However, these methods are not preferable in that the production method is complicated, that expensive catalyst components must be used, or that industrial catalysts are produced.

"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 has an object to solve the problem of a supply gas when ammoxidizing an organic compound. It is an object of the present invention to provide a method capable of producing a molybdenum-containing catalyst having low ammonia flammability and capable of giving an ammoxidation product in a good yield without adding water or the like by a simple means.

"Means for Solving the Problems" In order to achieve the above object, the method for producing a molybdenum-containing ammoxidation catalyst according to the present invention comprises: (A) at least one element selected from the group consisting of iron, bismuth and tellurium; B) A method for producing an oxide catalyst containing molybdenum as an essential component, comprising the steps of: preparing a solution or slurry containing a raw material of the component (A) such as iron and a molybdenum compound;
Is adjusted to a range exceeding 7, and then the solution or slurry is dried and fired.

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

Mo _a C _c D _d E _e F _f O _g (where C is at least one element selected from the group consisting of Fe, Bi and Te; D is Ni, Co, Mg, Cr, Mn, Cu, Zn, Ga, Ge, Cd, In,
Sn, Sb, V, W, Re, Pb, Ru, Rh, Pd, Os, Ir, Pt, T
h, U, La, Ce, Pr, Nd, Sm, Eu, Gd, Al, Ti, Ta, Nb
At least one element selected from the group consisting of P and B; E is at least one element selected from the group consisting of P and B; F is Li, Na, K, Rb, Cs, Ca, Sr, Ba and Tl At least one element selected from the group consisting of: O is oxygen, and the subscripts a, b, c, d, e, f, and g represent atomic ratios, and when a = 8 to 12, c = 0.5 to 20 (preferably 0.5 to 15) d = 0 to 25 (preferably 0 to 23) e = 0 to 5 (preferably 0 to 3) f = 0 to 5 (preferably 0 to 3) and g = the above components The numbers corresponding to the oxides formed by bonding are shown. The optional components other than molybdenum and the C component can be appropriately selected and added for adjusting the selectivity of the reaction product, the reaction rate, the physical properties of the catalyst, and the like.

Starting materials for each component constituting the present catalyst can be selected from many types such as oxides, hydroxides, chlorides and nitrates of the respective elements.

For example, as a raw material of the molybdenum component, molybdenum oxide such as molybdenum trioxide, molybdic acid, ammonium paramolybdate, molybdic acid such as ammonium metamolybdate, or a salt thereof, phosphomolybdic acid, silicomolybdic acid A heteropoly acid containing molybdenum, a salt thereof, or the like is used.

Ferrous oxide, ferric oxide, ferric oxide, iron nitrate, iron chloride and iron hydroxide can be used as a raw material for the iron component. Good.

As a raw material of the bismuth component, bismuth salts such as bismuth nitrate and bismuth sulfate, bismuth trioxide, and nitric oxide of metal bismuth are used.

As the raw material of the tellurium component, telluric acid, tellurous acid, tellurium dioxide, tellurium trioxide, metal tellurium dissolved in nitric acid, and the like are used.

In the case where elements represented by the empirical formulas D, E, F and the like are included as optional components in the catalyst, the optional components may be used as starting materials for the catalyst in the form of oxides, hydroxides, chlorides, nitrates or other compounds. Used for raw materials.

According to the present invention, the pH of a solution or slurry containing the raw material of the component (A) such as iron and a molybdenum compound (hereinafter simply referred to as a slurry or the like) is adjusted to a range of more than 7. Thereafter, the catalyst is dried and then calcined to obtain the desired catalyst.

It is desirable that the slurry and the like are highly dispersed and homogenized. When the pH is 7 or less, the slurry or the like may have a high viscosity or become a gel, so that it is difficult to stir the slurry or the like, and not only is it not possible to obtain a uniform slurry, but also the final Since the performance of the resulting catalyst is high in ammonia / combustibility and the yield of the target product is low, it is preferable to adjust the pH of the slurry or the like to a range exceeding 7.

In the method of the present invention, the heat treatment of the slurry or the like is not always necessary, but after adjusting the pH of the slurry or the like to a region opposite to 7 or more, the heat treatment in the temperature range of 50 ° C to 120 ° C is not required. This is desirable for stabilizing the properties of the catalyst and for further improving the performance of the catalyst finally obtained. In this case, the heating time is preferably at least 10 minutes at the set temperature. When the pH of the slurry or the like is 7 or less, a catalyst produced by performing a heat treatment and thereafter adjusting the pH of the slurry or the like to a range exceeding 7 has low performance.

In the method of the present invention, the pH of the slurry or the like is adjusted to 7
After the heat treatment is performed at a temperature of 50 ° C. to 120 ° C., and then the pH of the slurry or the like is adjusted to 7 or less, the physical properties of the finally obtained catalyst are improved particularly in the strength. You.

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

The catalyst exhibits excellent activity without a carrier, but may also be combined with a suitable carrier. That is, the catalyst can be prepared to contain about 20% to 90% of the total active ingredients. As the carrier, silica, alumina, zirconia, silica-alumina, silicon carbide, alundum and inorganic silicate can be used.

The size and shape of the catalyst are not particularly limited, and the catalyst is formed into an arbitrary shape and size such as a pellet, a tablet, a sphere, a granule, and a powder according to a use state.

The catalyst produced by the method of the present invention can be used for an ammoxidation reaction of an organic compound. Examples of the organic compound include propylene, isobutene, methanol, ethanol, tertiary butanol, methyl tertiary butyl ether, and the like, and the corresponding nitriles can be obtained in high yield. Especially propylene, isobutene,
Favorable results are obtained by applying it to the ammoxidation reaction of tertiary butanol.

The catalyst of the present invention can be used in a fixed bed or a fluidized bed. The reaction is carried out by supplying the starting organic compound, ammonia and oxygen to a reactor filled with the catalyst of the present invention. Air is the preferred oxygen source for economic reasons. The air may be suitably enriched with oxygen.

Although the molar ratio of oxygen / raw organic compound in the raw material supplied to the reactor 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,
A relatively low molar ratio, about 1.
It may be in the range of 5 to about 2.5. The molar ratio of ammonia / raw organic compound in the raw material supplied to the reactor is about 0.8.
The catalyst produced by the process of the present invention has a relatively low molar ratio due to the low combustion rate of ammonia, and a sufficiently good target product in the range of about 0.9 to about 1.3. Is obtained. In addition, an inert gas such as air or water vapor may be supplied as needed.

The reaction temperature ranges from about 380 ° C to about 500 ° C, especially about 40 ° C.
A range from 0 ° C to about 480 ° C is preferred.

The reaction pressure is suitably in the range from about normal pressure to about 3 kg / cm ² G. The apparent contact time suitably ranges from about 1 to about 20 seconds.

Hereinafter, the configuration and effects of the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

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 equations.

Abrasion resistance test Test method for synthetic cracking, known as a test method for fluid catalytic cracking catalysts
Catariz, (Test Method For Synthetic Cracking
Catalysts), published by American Cyanamid Company, 6 / 31-4m-1 / 57. The wear loss (%) was determined by the following equation.

Abrasion loss (%): R = B x 100 / (CA) where A = weight of catalyst with abrasion loss from 0 to 5 hours B = weight of catalyst with abrasion loss from 5 to 20 hours C = subjected to test This test was conducted at C = 500 (g). The higher the wear resistance of the catalyst, the smaller the wear loss (%) R value.

Examples 1-1 to 1-3 The empirical formula is Mo ₁₀ Bi _1.0 Fe _2.0 Ni _6.5 Sb ₁₅ P _0.2 K _0.4 O
_A catalyst which was _71.7 (SiO ₂ ) ₆₀ was prepared by the following preparation method.

3.92 g of potassium nitrate were dissolved in 20 ml of water and added to 1745 g of 20% silica sol. To this solution, 171.0 g of ammonium paramolybdate dissolved in 510 ml of water was added with stirring. Subsequently, a solution of 225.6 g of antimony tetroxide powder and 186.8 g of nickel nitrate in 190 ml of water, a solution of 79.8 g of iron nitrate in 80 ml of water, a solution of 47.9 g of bismuth nitrate in 48 ml of 10% nitric acid, and a solution of 85% phosphorus 2.23 g of an aqueous acid solution was sequentially added. 15% aqueous ammonia was added to this slurry with stirring to adjust the pH to 8.

Inlet temperature of the slurry in a rotary disk type spray dryer is 320
℃, the outlet temperature was controlled at 160 ℃, spray-dried.
The fine particles thus obtained were heat-treated at 250 ° C., baked at 400 ° C. for 2.5 hours, and finally baked at 620 ° C. for 3 hours. The wear loss R value of this catalyst was 5.1%.

Example 2 A catalyst having the same composition was produced in the same manner as in Example 1 except that the slurry adjusted to pH 8 was subjected to heat treatment under reflux at 100 ° C. for 2 hours. The wear loss R value of this catalyst was 6.3%.

Example 3 A slurry having the same composition was produced in the same manner as in Example 1 except that the slurry adjusted to pH 8 was subjected to heat treatment under reflux at 100 ° C. for 2 hours, and then the pH of the slurry was adjusted to 4. The wear loss R value of this catalyst was 3.2%.

Example 4 The experimental formula is Mo ₁₀ Bi _2.5 Fe _2.0 Ni _5.5 Sb ₅ K _0.2 O _72.35 (Si
A catalyst of O ₂ ) ₆₀ was prepared by the following preparation method.

2.32 g of potassium nitrate was dissolved in 23 ml of water and added to 2067 g of 20% silica sol. Under stirring, 202.5 g of ammonium paramolybdate was dissolved in 610 ml of water and added to this solution. Subsequently, a solution in which 89.1 g of antimony tetroxide powder and 187.2 g of nickel nitrate were dissolved in 190 ml of water, a solution in which 94.6 g of iron nitrate was dissolved in 95 ml of water, and a solution in which 141.9 g of bismuth nitrate was dissolved in 140 ml of 10% nitric acid were sequentially added. . Next, agitate the slurry 28
% Ammonia water was added to adjust the pH to 10. Spray drying and firing were performed according to the method of Example 1 and fired at 600 ° C.

Example 5 The empirical formula was Mo ₁₀ Bi _1.5 Fe _1.5 Ni _6.0 P _1.0 K _0.2 O _43.1 (SiO 2
₂ ) A catalyst of ₆₀ was prepared by the following preparation method.

2.68 g of potassium nitrate were dissolved in 25 ml of water and added to 2387 g of 20% silica sol. Under stirring, 233.8 g of ammonium paramolybdate was dissolved in 700 ml of water and added to this solution. Subsequently, a solution in which 235.7 g of nickel nitrate was dissolved in 235 ml of water, a solution in which 81.9 of iron nitrate was dissolved in 80 ml of water, and 98.3 g of bismuth nitrate
Was dissolved in 100 ml of 10% nitric acid, and an 85% phosphoric acid aqueous solution 15.
3 g were added sequentially. The slurry was adjusted to pH 11 by adding 15% aqueous ammonia with stirring, spray-dried and fired according to the method of Example 1, and fired at 580 ° C.

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

Examples 9 to 11 Using chromium nitrate as a raw material for a chromium component, cobalt nitrate as a raw material for a cobalt component, and magnesium nitrate as a raw material for a magnesium component, adding each aqueous solution after ammonium paramolybdate to adjust the pH of the slurry
Except having changed to 9.5, the catalyst of the composition shown in Examples 9-11 of Table 1 was manufactured by the same preparation method as Example 2.

Examples 12 to 14 Zinc nitrate as a raw material of the zinc component, manganese nitrate as a raw material of the manganese component, using lanthanum nitrate as a raw material of the lanthanum component, each aqueous solution was added after ammonium paramolybdate, and the pH of the slurry was adjusted to 8.5. Example 12 to 14 of Table 2 were prepared in the same manner as in Example 2 except that
Was produced.

Examples 15-17 Cerium nitrate as a raw material of the cerium component, ammonium paratungstate as a raw material of the tungsten component,
The same preparation method as in Example 1 was repeated except that ammonium metavanadate was used as a raw material for the vanadium component, and ammonium paramolybdate was added to each of them and the pH of the slurry was adjusted to 8.5. A catalyst of the indicated composition was produced.

Examples 18-22 Cesium nitrate as a raw material of cesium component, calcium nitrate as a raw material of calcium component, orthoboric acid as a raw material of boron component, nitric acid suspension of tin metal powder as a raw material of tin component, palladium nitrate as a raw material of palladium component , And the pH of the slurry was adjusted to 9.5 before the heat treatment and to 2 after the heat treatment, respectively, except that the pH of the slurry was adjusted to 2 after the heat treatment. Catalysts having the compositions shown in Examples 18 to 22 were produced.

Comparative Examples 1-1 to 1-3 A catalyst having the same composition was produced in the same manner as in Example 1-1, except that the pH of the slurry obtained by mixing the catalyst raw materials was adjusted to 2 with 15% aqueous ammonia.

Comparative Example 2 A catalyst having the same composition was produced by the same preparation method as in Example 1 except that the pH of the slurry containing the catalyst raw materials was adjusted to 5 by adding 15% aqueous ammonia.

Comparative Example 3 The pH of the slurry before the heat treatment was adjusted to 2.0 with 15% aqueous ammonia.
A catalyst having the same composition was produced by the same preparation method as in Example 2 except that the catalyst was prepared as follows.

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

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

Comparative Examples 8 to 10 The pH of the slurry before and after the heat treatment was adjusted to 15%.
Example 10, except that ammonia water was added to prepare 3,
Catalysts having compositions corresponding to 11 and 14 were produced.

Comparative Examples 11 to 12 The pH of the slurry before and after the heat treatment was adjusted to 15%.
Catalysts having compositions corresponding to Examples 16 and 20 were prepared except that aqueous ammonia was adjusted to 2.

For the catalysts of Examples 1 to 22, and Comparative Examples 1 to 12,
The following activity tests were performed.

Activity test (Ammoxidation of propylene)
Packed into a fluidized bed reactor so as to have a predetermined contact time,
The temperature was maintained at a predetermined reaction temperature. In this reactor, the molar ratio of propylene: ammonia: oxygen is 1: 1.1 to 1.3:
A mixed gas of propylene, ammonia, and air, which was 1.95, was supplied at 6.51 (NTP conversion) per hour. The reaction pressure is normal pressure.

However, the activity tests of Example 1 and Comparative Example 1 were carried out while changing the propylene: ammonia ratio to 1:13, 1: 1.2, and 1: 1.1, and were respectively 1-1, 1-2, and 1-3. As shown. In other examples, the activity test was performed with the propylene: ammonia ratio fixed at 1: 1.2.

 Reaction conditions and activity test results are shown in Tables 1 to 3.

Example 23 The empirical formula was Mo ₁₀ Bi _8.5 Ni _1.5 Sb _3.5 P _0.75 K _1.0 O _51.9 (Si
A catalyst of O ₂ ) ₆₀ was prepared by the following preparation method.

Dissolve 10.4 g of potassium nitrate in 100 ml of water and add 1855 g of 20%
Added to silica sol. To this solution, 181.6 g of ammonium paramolybdate dissolved in 545 ml of water was added with stirring. Then, a solution of 55.9 g of antimony tetroxide powder and 45.8 g of nickel nitrate in 45 ml of water, 432.9 g of bismuth nitrate in 10% nitric acid
A solution dissolved in 430 ml and 8.9 g of an 85% phosphoric acid aqueous solution were sequentially added. Add 15% aqueous ammonia under stirring to this slurry
The pH was adjusted to 9.5.

Inlet temperature of the slurry in a rotary disk type spray dryer is 320
℃, the outlet temperature was controlled at 160 ℃, spray-dried.
The dried catalyst was heat-treated at 250 ° C., and calcined at 440 ° C. for 2.5 hours. The catalyst was wetted with a crusher and formed into a 2 mm × 2 mm φ column. The catalyst was finally calcined at 600 ° C.

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

Examples 25 to 26 By the same preparation method as in Example 9, catalysts having the compositions shown in Examples 25 to 26 in Table 4 were produced. However, the slurry was subjected to heat treatment after pH adjustment.

Example 27 A catalyst having the composition shown in Example 18 of Table 4 was produced in the same manner as in Example 23. However, the slurry was subjected to heat treatment and pH adjustment again after pH adjustment.

Comparative Example 13 A catalyst having the same composition was produced by the same preparation method as in Example 23 except that the pH of the slurry mixed with the catalyst raw material was adjusted to 3 by adding 15% aqueous ammonia.

Comparative Example 14 A catalyst having the same composition was produced by the same preparation method 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 having the same composition was produced by the same preparation method as in Example 25 except that the pH of the slurry before the heat treatment was adjusted to 0.8 with 10% nitric acid.

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

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

Activity test (Ammoxidation of insobutene) Dry, wet, mold into 2mm x 2mmφ column, 600
The catalyst finally calcined at ℃ was filled into a U-shaped reactor having an inner diameter of 16 mmφ so that the contact time was 2 seconds. This was heated by a molten salt bath composed of an equal mixture of sodium nitrite and potassium nitrate, and maintained at a reaction temperature of 390 ° C. Into this reactor, a mixed gas of isobutene, ammonia and air having a ratio of isobutene: ammonia: oxygen of 1: 1.2: 2.3 was supplied at a rate of 71 (in NTP) per hour.
The reaction pressure is normal pressure.

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

According to the present invention, a molybdenum-containing ammoxidation catalyst can be produced by simple means without the need for complicated operations for forming various molybdates in advance, and this catalyst has an ammonia flammability. When the ammoxidation of an organic compound is carried out because of its small value, the desired ammoxidation product is obtained in high yield even at a low ammonia / raw organic compound molar ratio.

Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI // C07B 61/00 300 C07B 61/00 300 C07C 255/08 C07C 255/08 255/24 255/24 (58) Field surveyed (Int. Cl. ⁶ , DB name) B01J 21/00-37/36

Claims (3)

(57) [Claims] 1. A method for producing an oxide catalyst represented by the following empirical formula for use in ammoxidation, comprising: a solution containing a raw material of the following component C such as iron; and a component when d ≠ 0 in the following empirical formula. A solution containing D, a solution containing component E, a solution containing component F, and a solution containing a molybdenum compound when e ≠ 0 are mixed, and the pH of the solution or slurry is adjusted to a range of more than 7. And then drying and baking the solution or slurry to produce a molybdenum-containing ammoxidation catalyst. MoaCcDdEeFfOg (where C is at least one element selected from the group consisting of Fe, Bi and Te, D is Ni, Co, Mg, Cr, Mn, Cu, Zn, Ga, Ge, Cd, In, S
n, Sb, V, W, Re, Pb, Ru, Rh, Pd, Os, Ir, Pt, T
h, U, La, Ce, Pr, Nd, Sm, Eu, Gd, Al, Ti, Ta, Nb
And at least one element selected from the group consisting of P and B, provided that at least one element selected from the group consisting of P and B is not contained simultaneously with each of W and Ce, and Ni and Co. , F is at least one element selected from the group consisting of Li, Na, K, Rb, Cs, Ca, Sr, Ba and Tl, O is oxygen, and subscripts a, b, c, d, e, f And g represent an atomic ratio, a = 8 to 12 c = 0.5 to 20 d = 0 to 25 e = 0 to 5 f = 0.05 to 1 and g = a number corresponding to an oxide formed by combining the above components Is shown. ) 2. A solution or slurry containing a catalyst component whose pH has been adjusted to a range of more than 7 according to claim 1,
A method for producing a molybdenum-containing ammoxidation catalyst, which comprises subjecting the composition to a heat treatment at a temperature in the range of 120 ° C to 120 ° C, followed by drying and firing. 3. A solution or slurry containing the catalyst component whose pH has been adjusted to a range exceeding 7 according to claim 1,
A method for producing a molybdenum-containing ammoxidation catalyst, which comprises heating at a temperature in the range of 120 ° C to 120 ° C, adjusting the pH to 7 or less, drying and calcining.