KR20010004567A - Catalyst for production of acrolein - Google Patents

Abstract

PURPOSE: Provided is a catalyst used in a process for preparing acrolein and acrylic acid by means of reacting air or gas containing oxygen with propylene. CONSTITUTION: The catalyst is represented by the formula: MoaBibFecXdYeZfTigOh, wherein X is at least one atom selected from the group consisting of Co and Ni, Y is at least one atom selected from the group consisting of K and Rb, Z is at least one atom selected from the group consisting of W, Si, Ag, Sb, and a, b, c, d, e, f, g, h represent the atom ratio of each elements, wherein a : b : c : d : e : f : g ranges 12 : 0.5-2 : 0.5-2 : 3-8 : 0.005-0.2 : 0.5-10 : 1-20 and h is determined according to acidic condition of each components. The Ti is added in the state of anatase titanium oxide when the catalyst is prepared.

Description

Catalyst for Acrolein and Acrylic Acid Production {CATALYST FOR PRODUCTION OF ACROLEIN}

[Industrial use]

The present invention relates to a catalyst for producing acrolein and acrylic acid, and more particularly, to a catalyst used in a process for producing acrolein and acrylic acid by reacting propylene with a gas containing air or oxygen.

[Prior art]

When propylene is reacted with oxygen-containing gas or air in the presence of a catalyst, acrolein and acrylic acid are produced and CO, CO ₂ and other side reaction products are produced. The distribution of each component in these reaction products is determined by the catalyst and reaction conditions. Higher selectivity catalysts, such as acrolein or acrylic acid, and catalysts with high activity at low reaction temperatures are of greater commercial value. In order to increase the conversion of propylene using a low activity catalyst, the reaction temperature must be increased. Due to the nature of the oxidation reaction, complete oxidation reactions such as CO and CO ₂ production dominate at high temperatures, reducing the selectivity for acrolein. In addition, at a high reaction temperature, the catalyst deactivation is promoted due to volatilization of the active ingredient and a decrease in specific surface area, thereby decreasing the service life of the catalyst.

In response to these commercial demands, many catalysts having high activity and high selectivity to acrolein and acrylic acid have been proposed. US Pat. No. 2,941,007 discloses a catalyst consisting of bismuth molybdate and bismuth phosphomolybdate, while US Pat. No. 3,171,859 uses a catalyst consisting of Fe, Bi, P, Mo, and US Pat. 3,522,299 reported catalysts consisting of Ni, Co, Fe, Bi, Mo, P, As, B, K, Rb, Cs. U. S. Patent No. 3,089, 909 discloses a catalyst composed of W, Mo, and U. S. Patent 3,825, 600 discloses a catalyst composed of Mo, Co, Fe, Bi, W, Si alkali metal and the like. Some of these have not been sufficiently high in acrolein and acrylic acid yields for commercial application, but improved catalysts are constantly being proposed. For example, U.S. Patent 4,224,187, U.S. Patent 4,248,803, U.S. Patent 4,267,386, U.S. Patent 4,306,088, U.S. Patent 4,380,664, U.S. Patent 4,873,217, U.S. Patent 5,017,542 and the like And a catalyst and a preparation method for controlling the composition ratio to increase the propylene conversion and the acrolein and acrylic acid yield.

Although these various disclosed methods are known, satisfactory catalysts with high catalytic activity and high selectivity for acrolein and acrylic acid have not yet been developed.

It is therefore an object of the present invention to provide a catalyst that exhibits high activity in propylene conversion while maintaining high selectivity for acrolein and a process for its preparation.

[Means for solving the problem]

The present invention to achieve the above object

Provided is a catalyst having a composition represented by the following formula (1) used to react propylene with a gas containing air or oxygen to produce acrolein and acrylic acid.

[Formula 1]

Mo _a Bi _b Fe _c X _d Y _e Z _f Ti _g O _h

Where

Mo is molybdenum, Bi is bismuth, Fe is iron, X is at least one element selected from Co and Ni, Y is at least one element selected from K and Rb, and Z is from W, Si, Ag, Sb At least one element selected, Ti is titanium, a, b, c, d, e, f, g, h represent the atomic ratio of each element, and when a is 12 based on a, b is 0.5-2, c is 0.5-2, d is 3-8, e is 0.005-0.2, f is 0.5-10, g is 1-20, h is a numerical value determined according to the oxidation state of each said component.

Hereinafter, the present invention will be described in detail.

In the process of preparing the catalyst suspension from the metal salts of the catalyst component except titanium in the catalyst component represented by Chemical Formula 1 in the usual manner, powdered titanium oxide was added to make the catalyst suspension, dried and pulverized, and calcined under air flow. To prepare a catalyst. Alternatively, the catalyst suspension, except for titanium, is dried and pulverized, mixed well with titanium oxide powder, and calcined under air flow at a temperature of 450 ° C. to prepare a catalyst.

The titanium oxide is preferably anatase, particularly preferably having a particle size of 1 m or less and a specific surface area of 10 to 50 m 2 / g.

When used commercially, the catalyst is molded into a constant size and shape by conventional methods such as extrusion before firing.

There is no particular limitation in the gas phase oxidation of propylene by using the catalyst prepared by the method of the present invention, and it may be carried out according to a conventionally performed method.

Through the following examples, comparative examples and test examples will be described the present invention in more detail. However, the examples illustrate the present invention and do not limit the present invention.

EXAMPLE

Example 1

50 g of water was dissolved in ammonium molybdate 24 g while heating and stirring at a temperature of 40 ° C (solution A). To solution A, 2.75 g of anatase titanium oxide (hereinafter titanium oxide) having a particle size of 1 m or less and a specific surface area of 22 m 2 / g are added.

To 20 g of water, 5.5 g of bismuth nitrate, 13.2 g of cobalt nitrate, 4.6 g of iron nitrate, and 0.0673 g of rubidium nitrate were mixed, and 2.0 g of nitric acid was added to dissolve (solution B).

The catalyst suspension was prepared by dropping solution B with vigorous stirring of solution A to which the titanium oxide was added.

The prepared catalyst slurry was dried in an oven at 120 ° C. to obtain a dried product, and then ground to a powder having a diameter of 2 mm or less. The pulverized catalyst powder was calcined in an air atmosphere at 450 ° C., and then pulverized, and catalytic activity was verified using a catalyst powder having a particle size of 0.125 to 0.25 mm. The composition of the prepared catalyst is Mo ₁₂ Bi ₁ Fe ₁ Co ₄ Rb _0.04 Ti ₃ .

Example 2

A catalyst was prepared in the same manner as in Example 1 except that 5.5 g of titanium oxide was used to obtain a catalyst having a composition of Mo ₁₂ Bi ₁ Fe ₁ Co ₄ Rb _0.04 Ti ₆ .

Example 3

A catalyst was prepared in the same manner as in Example 1 except that 11 g of titanium oxide was used to obtain a catalyst having a composition of Mo ₁₂ Bi ₁ Fe ₁ Co ₄ Rb _0.04 Ti ₁₂ .

Example 4

A catalyst was prepared in the same manner as in Example 1 except that 22 g of titanium oxide was used to obtain a catalyst having a composition of Mo ₁₂ Bi ₁ Fe ₁ Co ₄ Rb _0.04 Ti ₂₄ .

Example 5

A catalyst suspension was prepared in the same manner as in Example 1 except that 33 g of titanium oxide was used to obtain a catalyst having a Mo ₁₂ Bi ₁ Fe ₁ Co ₄ Rb _0.04 Ti ₃₆ composition.

Comparative Example 1

50 g of water was dissolved in ammonium molybdate 24 g by heating and stirring at 40 ° C (solution A).

To 20 g of water, 5.5 g of bismuth nitrate, 13.2 g of cobalt nitrate, 4.6 g of iron nitrate, and 0.0673 g of rubidium nitrate were mixed and dissolved by adding 2.0 g of nitric acid (solution B).

Catalyst B was prepared by dropping Solution B with vigorous stirring of Solution A. The catalyst suspension was dried in a drying furnace maintained at 120 ° C. to recover dry matter, and then ground to powder of 2 mm or less in diameter. The pulverized catalyst powder is calcined at 450 ° C. under air atmosphere. Thus, a catalyst having a composition of Mo ₁₂ Bi ₁ Fe ₁ Co ₄ Rb _0.04 was obtained. The calcined catalyst was ground to a particle size of 0.125 to 0.25 mm to verify the catalytic activity.

Comparative Example 2

In order to compare the catalytic performance of TiO ₂ , it was tested with titanium oxide having a specific surface area of 22 m 2 / g and a particle size of 0.125 to 0.25 mm.

Example 6

Titanium oxide (5.5 g) was added to 20 g of the unfired catalyst powder prepared in Comparative Example 1, and the mixture was uniformly mixed in a mortar and then fired in an air atmosphere at 450 ° C. The calcined powder was again pulverized to obtain a catalyst powder having a catalyst particle size of 0.125 to 0.25 mm. The composition of the prepared catalyst is Mo ₁₂ Bi ₁ Fe ₁ Co ₄ Rb _0.04 Ti ₁₂ .

Example 7

Titanium oxide 11 g was added to 20 g of the unfired catalyst powder prepared in Comparative Example 1, uniformly mixed in a mortar and then fired in an air atmosphere at 450 ° C. The calcined powder was pulverized again to obtain a catalyst powder having a catalyst particle size of 0.125 to 0.25 mm. The composition of the prepared catalyst is Mo ₁₂ Bi ₁ Fe ₁ Co ₄ Rb _0.04 Ti ₂₄ .

Comparative Example 3

50 g of water was dissolved in ammonium molybdate 24 g by heating and stirring at 40 ° C (solution A). 0.87 g of Sb ₂ O ₄ having particles of 1 μm or less was added to this solution A.

To 20 g of water, 5.5 g of bismuth nitrate, 13.2 g of cobalt nitrate, 4.6 g of iron nitrate, and 0.0673 g of rubidium nitrate were mixed and dissolved by adding 2.0 g of nitric acid (solution B).

A solution suspension was prepared by dropping Solution B while vigorously stirring Solution A to which the antimony oxide was added.

The prepared catalyst slurry was dried in an oven at 120 ° C. to obtain a dried product, and then ground to a powder having a diameter of 2 mm or less. The pulverized catalyst powder was calcined in an air atmosphere at 450 ° C., and then pulverized, and catalytic activity was verified using a catalyst powder having a particle size of 0.125 to 0.25 mm. The composition of the prepared catalyst is Mo ₁₂ Bi ₁ Fe ₁ Co ₄ Rb _0.04 Sb _0.5 .

Example 8

Titanium oxide (1.38 g) was added to 20 g of the unfired catalyst powder prepared in Comparative Example 3, and the mixture was uniformly mixed in a mortar and then fired in an air atmosphere at 450 ° C. The calcined powder was pulverized again to obtain a catalyst powder having a catalyst particle size of 0.125 to 0.25 mm. The composition of the prepared catalyst is Mo ₁₂ Bi ₁ Fe ₁ Co ₄ Rb _0.04 Sb _0.5 Ti ₃ .

Comparative Example 4

50 g of water was dissolved in ammonium molybdate 24 g by heating and stirring at 40 ° C (solution A).

To 20 g of water, 5.5 g of bismuth nitrate, 13.2 g of cobalt nitrate, 4.6 g of iron nitrate, 0.0673 g of rubidium nitrate, and 0.096 g of silver nitrate were mixed and dissolved by adding 2.0 g of nitric acid (solution B).

Catalyst B was prepared by dropping Solution B with vigorous stirring of Solution A.

The catalyst suspension was dried in a drying furnace maintained at 120 ° C. to recover dry matter, and then ground to powder of 2 mm or less in diameter. The pulverized catalyst powder was calcined at 450 ° C. under air atmosphere. Thus, a catalyst having a catalyst composition of Mo ₁₂ Bi ₁ Fe ₁ Co ₄ Rb _0.04 Ag _0.05 was obtained. The calcined catalyst was ground to a particle size of 0.125 to 0.25 mm to verify the catalytic activity.

Example 9

Titanium oxide (1.38 g) was added to 20 g of the unfired catalyst powder prepared in Comparative Example 4, and the mixture was uniformly mixed in a mortar and then fired in an air atmosphere at 450 ° C. The calcined powder was pulverized again to obtain a catalyst powder having a catalyst particle size of 0.125 to 0.25 mm. The composition of the prepared catalyst is Mo ₁₂ Bi ₁ Fe ₁ Co ₄ Rb _0.04 Ag _0.05 Ti ₃ .

Test Example

(Activity Test of Catalyst)

In the known methods, the conversion of propylene is typically 90% or more, and the selectivity for acrolein and acrylic acid is about 85 to 98%, and the yield of acrolein and acrylic acid is reported to be 77 to 98%. However, the performance test conditions of the catalysts differ from method to method, and it is not significant to compare the values given in each prior art document as they are. In addition, the catalytic activity of the catalyst pellets is known to appear a lot of difference depending on the method of treating the catalyst powder. Although the inherent activity of the catalyst is the same, the apparent activity of the catalyst is also greatly changed depending on the difference in physical properties that occur when the catalyst is formed. US Patent 4,298,763, US Patent 4,438,217, US Patent 4,442,308, US Patent 4,511,671, U.S. Patent No. 5,017,542 and the like reported that the apparent activity varies greatly even when the physical properties such as pellet shape, pore size and pore size distribution of the catalyst are varied.

Therefore, the present invention confirmed the improvement of the catalytic performance by measuring the intrinsic activity of the catalyst in the state of the catalyst powder. That is, the effect of the diffusion rate of the reactants and products was removed by minimizing the particle size of the catalyst, and the performance was tested in the region where the conversion rate was approximately 30% or less by sufficiently increasing the space velocity.

Therefore, the activity test for the catalysts prepared in Examples and Comparative Examples was performed as follows.

The particle size is charged to the catalyst powder 0.125~0.25 mm to 0.2 g iron reaction tube, and propylene 7.0 vol%, O ₂ 12.6% by volume, H ₂ O 8.0% by volume, N ₂ 72.4% by volume of the mixed gas of about 30,000 hr ^{- It} was introduced at a space velocity of ¹ furnace. The temperature outside the reactor was maintained at 350 ° C or 370 ° C. The results of the reaction experiments of the Examples and Comparative Examples are shown in Table 1.

Conversion rate, selectivity, and yield used in the present invention was defined by the following equations (1), (2), (3).

[Equation 1]

[Equation 2]

[Equation 3]

division Catalyst composition Reaction temperature (℃) Propylene Conversion Rate (%) Acrolein selectivity (%) Acrolein yield (%) Example 1 Mo ₁₂ Bi ₁ Fe ₁ Co ₄ Rb _0.04 Ti ₃ 350 29.1 94.5 27.5 Example 2 Mo ₁₂ Bi ₁ Fe ₁ Co ₄ Rb _0.04 Ti ₆ 350 29.9 94.0 28.1 Example 3 Mo ₁₂ Bi ₁ Fe ₁ Co ₄ Rb _0.04 Ti ₁₂ 350 31.4 93.5 29.4 Example 4 Mo ₁₂ Bi ₁ Fe ₁ Co ₄ Rb _0.04 Ti ₂₄ 350 24.8 90.0 22.3 Example 5 Mo ₁₂ Bi ₁ Fe ₁ Co ₄ Rb _0.04 Ti ₃₆ 350 19.5 87.0 17.0 Comparative Example 1 Mo ₁₂ Bi ₁ Fe ₁ Co ₄ Rb _0.04 350 25.7 94.8 24.4 Comparative Example 2 TiO ₂ 350 15.9 0 0 Example 6 Mo ₁₂ Bi ₁ Fe ₁ Co ₄ Rb _0.04 Ti ₁₂ 350 30.4 92.1 28.0 Example 7 Mo ₁₂ Bi ₁ Fe ₁ Co ₄ Rb _0.04 Ti ₂₄ 350 22.6 88.5 20.0 Comparative Example 3 Mo ₁₂ Bi ₁ Fe ₁ Co ₄ Rb _0.04 Sb _0.5 370 15.5 96.2 14.9 Example 8 Mo ₁₂ Bi ₁ Fe ₁ Co ₄ Rb _0.04 Sb _0.5 Ti ₃ 370 18.2 96.1 17.5 Comparative Example 4 Mo ₁₂ Bi ₁ Fe ₁ Co ₄ Rb _0.04 Ag _0.05 370 25.7 97.0 24.9 Example 9 Mo ₁₂ Bi ₁ Fe ₁ Co ₄ Rb _0.04 Ag _0.05 Ti ₃ 370 27.3 96.5 26.3

As described above, in the present invention, it can be seen that by adding a predetermined amount of titanium in the form of titanium oxide as the catalyst composition, the intrinsic activity of the catalyst can be improved while maintaining high selectivity for acrolein.

Claims (6)

Catalysts for preparing acrolein and acrylic acid represented by Formula 1 below: [Formula 1] Mo _a Bi _b Fe _c X _d Y _e Z _f Ti _g O _h Where Mo is molybdenum, Bi is bismuth, Fe is iron, X is at least one element selected from Co and Ni, Y is at least one element selected from K and Rb, Z is at least one element selected from W, Si, Ag, Sb, Ti is titanium, a, b, c, d, e, f, g, h represent the atomic ratio of each element, When a is 12 based on a, b is 0.5 to 2, c is 0.5 to 2, d is 3 to 8, e is 0.005 to 0.2, f is 0.5 to 10, g is 1 to 20, and h is oxidation of each component. This value is determined by the state. In preparing a catalyst for producing acrolein and acrylic acid, a) catalyst excluding titanium in the catalyst component represented by the following formula (1) Powder state during the preparation of the catalyst suspension from the metal salt of the component To prepare a suspension by adding an anatase titanium oxide step; And b) drying, grinding and calcining the suspension in an air atmosphere A method for preparing a catalyst for producing acrolein and acrylic acid represented by the following Chemical Formula 1 comprising: [Formula 1] Mo _a Bi _b Fe _c X _d Y _e Z _f Ti _g O _h Where Mo is molybdenum, Bi is bismuth, Fe is iron, X is at least one element selected from Co and Ni, Y is at least one element selected from K and Rb, Z is at least one element selected from W, Si, Ag, Sb, Ti is titanium, a, b, c, d, e, f, g, h represent the atomic ratio of each element, When a is 12 based on a, b is 0.5 to 2, c is 0.5 to 2, d is 3 to 8, e is 0.005 to 0.2, f is 0.5 to 10, g is 1 to 20, and h is oxidation of each component. This value is determined by the state. The method of claim 2, a) adding anatase titanium oxide to the molybdenum salt solution; b) excluding molybdenum and anatase titanium oxide in Chemical Formula 1 Preparing a metal solution; c) a molybdenum salt solution added with titanium oxide in step a) and b) Preparing a catalyst suspension in which the solution of step is mixed; And d) drying the catalyst suspension of step c) under crushing and air atmosphere Firing step Catalyst production method for producing acrolein and acrylic acid comprising a. The method of claim 2 or 3, The anatase titanium oxide has a particle size of 1 μm or less and a specific surface area of 10 to 50 m 2 / g Acrolein and acrylic acid production catalyst production method. In preparing a catalyst for producing acrolein and acrylic acid, a) catalyst excluding titanium in the catalyst component represented by the following formula (1) Preparing a catalyst suspension with a metal salt of the component; b) drying and grinding the catalyst suspension of step a); c) mixing the pulverized catalyst powder of step b) with anatase titanium oxide Doing; And d) calcining the mixed powder of step c) in an air atmosphere A method for preparing a catalyst for producing acrolein and acrylic acid represented by the following Chemical Formula 1 comprising: [Formula 1] Mo _a Bi _b Fe _c X _d Y _e Z _f Ti _g O _h Where Mo is molybdenum, Bi is bismuth, Fe is iron, X is at least one element selected from Co and Ni, Y is at least one element selected from K and Rb, Z is at least one element selected from W, Si, Ag, Sb, Ti is titanium, a, b, c, d, e, f, g, h represent the atomic ratio of each element, When a is 12 based on a, b is 0.5 to 2, c is 0.5 to 2, d is 3 to 8, e is 0.005 to 0.2, f is 0.5 to 10, g is 1 to 20, and h is oxidation of each component. This value is determined by the state. The method of claim 5, The anatase titanium oxide has a particle size of 1 μm or less and a specific surface area of 10 to 50 m 2 / g Acrolein and acrylic acid production catalyst production method.