KR100794461B1 - Method for preparation of partial oxidation catalyst of methylbenzene by dry milling - Google Patents

Abstract

The present invention relates to a novel method for preparing a methylbenzene partial oxidation catalyst, and more particularly, methylbenzene partial oxidation, characterized in that dry milling after mixing a tungsten oxide powder and a refractory inorganic powder. It relates to a method for producing a catalyst.

According to the present invention, the catalyst components can be uniformly mixed, the content of tungsten oxide as a main component can be easily controlled, and a catalyst having a high content of tungsten oxide can be prepared, and thus the selectivity to the aromatic aldehyde and the unit weight of the catalyst There is an effect of providing a catalyst for partial oxidation of methylbenzenes which can improve the yield of sugar aromatic aldehydes.

Methylbenzenes, partial oxidation catalysts, tungsten oxides, aromatic aldehydes, milling

Description

METHODS FOR PREPARATION OF PARTIAL OXIDATION CATALYST OF METHYLBENZENE BY DRY MILLING}

1 is a graph showing the TPAL yield according to the reaction temperature of the catalyst for partial oxidation of methylbenzenes of Examples 1 to 7 and Comparative Examples 1 to 2 according to the present invention.

The present invention relates to a method for preparing a methylbenzene partial oxidation catalyst, and more specifically, it is possible to uniformly mix the catalyst components, and to easily control the content of tungsten oxide as a main component, especially a catalyst having a high content of tungsten oxide. Production of a catalyst for partial oxidation of methylbenzene, which can improve the selectivity for the corresponding aromatic aldehyde and the yield of aromatic aldehyde generation per unit weight of the catalyst by gas phase oxidation of methylbenzene using molecular oxygen It is about a method.

Aromatic aldehydes have a highly reactive aldehyde group and can be used for a wide range of applications. In particular, terephthalaldehyde having two aldehyde groups in the para position has attracted attention as a basic raw material for pharmaceutical products, pesticides, pigments, liquid crystal polymers, electrically conductive polymers, heat-resistant plastics and the like.

Conventional methods for preparing terephthalaldehyde include a method of dehydrating an intermediate that has undergone chlorination of p-xylene, or a hydrogenation method of dimethyl terephthalate, which has a complicated manufacturing process, high pressure, and environmentally unfriendly methods. Conditions and the like were unsuitable for economically mass production of terephthalaldehyde.

To overcome this, efforts have been made to mass-produce terephthalaldehyde by gas phase oxidation of p-xylene using molecular oxygen. Japanese Patent Publication No. 47-002086 discloses a mixed oxide catalyst having a composition in which the ratio of W and Mo is 1: 1 to 20: 1, and Japanese Patent Application Publication No. 48-047830 includes a catalyst containing V, Rb, or Cs. Is disclosed. U.S. Patent No. 3,845,137 discloses a catalyst consisting of at least one component selected from the group consisting of Ca, Ba, Ti, Zr, Hf, Tl, Nb, Zn and Sn in two components of W and Mo. US Patent No. 4,017,547 discloses a catalyst consisting of Mo oxide, W oxide or silicotungstic acid and Bi oxide. However, in the case of using these catalysts, there is a problem that the selectivity and yield of the target terephthalaldehyde is low, so there is a limit to the practical use in industry.

U.S. Patent No. 5,324,702 is selected from the group consisting of Fe, Zn, Zr, Nb, In, Sn, Sb, Ce and Bi by chemical vapor deposition (CVD) on a deboronized borosilicate crystal molecular sieve. A catalyst carrying one component and one component selected from the group consisting of V, Mo and W is disclosed. This catalyst has a relatively higher p-xylene conversion and terephthalaldehyde yield than the conventional catalyst, but it has a limit in increasing selectivity due to various by-products, and thus it is difficult to separate and purify.

U. S. Patent No. 6,458, 737 B1 discloses W as a main component, Sb, Fe, Co, Ni, Mn, Re, Cr, V, Nb, Ti, Zr, Zn, Cd, Y, La, Ce, B, Al, Tl, A catalyst consisting of at least one component selected from the group consisting of Sn, Mg, Ca, Sr, Ba, Li, Na, K, Rb and Cs is disclosed. In the case of using this catalyst, the yield of terephthalaldehyde is high, which is close to the practical use in industry. However, the terephthalaldehyde selectivity is not so high compared to the high p-xylene conversion rate, which is also a limitation in terms of separation and purification, and includes a Sb component that loses sublimation at a high temperature, thereby causing problems in terms of thermal stability and catalyst life of the catalyst.

As a result, in the case of using conventional catalysts, even if the yield of the desired terephthalaldehyde is low or the yield is high, the selectivity of the target is difficult to separate and purify, and because it uses a multi-component complex oxide, the composition and performance are uniform. It was not easy to prepare a catalyst having. In addition, since there is a problem that the catalyst life is short because it contains components with low thermal stability, there was a limit to practical use in the industry.

Korean Patent Application No. 10-2004-0089376 filed by the present inventors discloses a single component catalyst composed of tungsten oxide and a tungsten oxide catalyst supported on a refractory inorganic material. Compared to the conventional multicomponent composite oxide catalyst, the catalyst has a uniform catalyst performance, high catalyst stability, and high selectivity and yield for terephthalaldehyde.

In order to solve the problems of the prior art as described above, the present invention can be uniformly mixed with the catalyst components, it is easy to control the content of tungsten oxide as a main component, in particular can be prepared a catalyst with a high content of tungsten oxide, methyl It is an object of the present invention to provide a method for preparing a methylbenzene partial oxidation catalyst which can improve the selectivity for a corresponding aromatic aldehyde and the yield of aromatic aldehyde per unit catalyst weight by gas phase oxidation of benzene using molecular oxygen. do.

The above and other objects of the present invention can be achieved by the present invention described below.

In order to achieve the above object, the present invention is a methylbenzene partial oxidation in the method of producing a catalyst for methylbenzene partial oxidation consisting of tungsten oxide powder and a refractory inorganic powder, characterized in that dry milling is used. It provides a method for producing a catalyst.

Hereinafter, the present invention will be described in detail.

Method for producing a methylbenzene partial oxidation catalyst of the present invention

(a) mixing a catalyst component consisting of a tungsten oxide powder and a refractory inorganic powder, and

(b) Dry milling the powder mixed in the step (a)

It is made, including.

The raw material used in the production of the tungsten oxide powder is not particularly limited, and oxides, carbides, chlorides, sulfides, silicides, organic acid salts or heteropolyacids and the like may be used in addition to tungsten ammonium salts, and ammonium metatungstate is more preferable.

The content of the tungsten oxide powder is defined as the weight% of the tungsten oxide powder with respect to 100 parts by weight of the total mixture of the tungsten oxide powder and the refractory inorganic powder, it is preferable that the content is included in 20 to 98% by weight.

As the refractory inorganic powder, α-alumina, silica, titania, zirconia, silicon carbide, calcium aluminate or magnesium aluminate may be used.

In the step (b) dry milling, a ball may be used, and the ball may be zirconia, alumina, silicon nitride, silicon carbide, silicon nitride, ruby, sapphire, engineering plastic, stainless steel, or cemented carbide. , Zirconia or alumina balls are preferred.

The ball is preferably 1 to 30 mm in diameter, it is possible to use a single diameter ball, or a combination of balls of various diameters.

The mixing ratio of the ball and the catalyst component mixture is preferably 1: 1 to 100: 1 by weight.

In the step (b) dry milling, the milling method is not particularly limited, and a disk mill, a stone mill, an attention mill, or a shaker mill may be used. .

The dry milling time depends on the type of catalyst component mixture and the weight ratio of the mixture and the balls, preferably in the range of 0.5 to 48 hours.

The catalyst powder prepared by the step (b) of dry milling may be used in the catalytic reaction as it is in a powder state without a separate drying and firing process, or may be prepared by using a pellet. When preparing a pallet requiring strength, a binder and a solvent may be further used in addition to the catalyst powder prepared above, in which case a drying and firing process may be required.

In the present invention, methylbenzene refers to a compound in which at least one methyl group is directly bonded to the benzene ring, and representative examples thereof include p-xylene, o-xylene, m-xylene, psidodocumen, and mesh. And methylbenzenes having 8 to 10 carbon atoms such as styrene and durene.

The use of the catalyst for partial oxidation prepared by the production method of the present invention is to prepare a corresponding aromatic aldehyde by gas phase oxidation of methylbenzene using molecular oxygen. For example, terephthalaldehyde and p-tolualdehyde from p-xylene, phthalaldehyde and o-tolualdehyde from o-xylene, isophthalaldehyde and m-tolualdehyde from m-xylene, 2 from psoidocumen -Methyl terephthalaldehyde, 2,4-dimethylbenzaldehyde, 2,5-dimethylbenzaldehyde and 3,4-dimethylbenzaldehyde, 3,5-dimethylbenzaldehyde, 5-methylisophthalaldehyde and 1,3,5- from mesitylene Triformylbenzene, 2,5-dimethylterephthalaldehyde from duren, 4,5-dimethylphthalaldehyde, 2,4,5-trimethylbenzaldehyde, 2,4,5-triformyltoluene and 1,2,4,5 And-producing tetraformylbenzene, respectively. Among them, the catalyst for methylbenzene partial oxidation prepared by the production method of the present invention is particularly suitably used for producing terephthalaldehyde from p-xylene.

Hereinafter, preferred examples are provided to help understanding of the present invention, but the following examples are merely to illustrate the present invention, and the scope of the present invention is not limited to the following examples.

EXAMPLE

Example 1

Ammonium metatungstate was used as the tungsten oxide precursor. The aqueous ammonium metatungstate solution was dried in vacuo, further dried in an oven at 120 ° C. for 18 hours, and then calcined at 650 ° C. for 2 hours in an air atmosphere to obtain a tungsten oxide powder. As the refractory inorganic powder, α-alumina SA5205 (Saint-Gobain Norpro) was ground and used. 2 g of tungsten oxide powder is placed in a container, and 8 g of α-alumina powder is mixed into a container, and about 50 g of zirconia ball having a diameter of 5 mm and about 50 g of a ball having a diameter of 10 mm are mixed with each other. Zirconia ball was added to the mixture in a ratio of 10: 1, and dry milling with a shaker mill for 2 hours to prepare a catalyst of fine powder composed of tungsten oxide and α-alumina. The tungsten oxide content of the catalyst thus obtained accounted for 20% of the total weight of the catalyst. The catalyst powder was pressed to make a pellet, and then crushed again to filter the mesh to perform a catalyst performance experiment with a catalyst having a size of 200 μm.

Catalyst performance evaluation experiments used a continuous flow reactor made of quartz. 1 g of a catalyst having a size of 200 μm having a tungsten oxide content of 20% was charged to a quartz reactor, and p-xylene, oxygen, and nitrogen were flowed as reactants, and gas phase oxidation was performed under the conditions shown below. The results of the catalyst performance evaluation experiments are shown in Table 1 and FIG. 1.

Reaction pressure: normal pressure

Reactor body composition (volume ratio): p-xylene / oxygen / nitrogen = 0.5 / 12.5 / 87

                      (Oxygen / p-xylene = 25)

Total reaction gas flow rate: 100 cc / min

Reaction temperature: 520, 550, 580 ℃

Example 2

In Example 1, a catalyst having a tungsten oxide content of 40% based on the total weight of the catalyst was prepared using 4 g of tungsten oxide powder and 6 g of α-alumina powder, and the catalyst performance evaluation experiment was performed with 0.5 g of the prepared catalyst. Except that was carried out in the same manner as in Example 1.

Example 3

In Example 1, using 6 g of tungsten oxide powder and 4 g of α-alumina powder, a catalyst having a tungsten oxide content of 60% based on the total weight of the catalyst was prepared, and a catalyst performance evaluation experiment was performed using 0.333 g of the prepared catalyst. Except that was carried out in the same manner as in Example 1.

Example 4

In Example 1, a catalyst having a tungsten oxide content of 80% based on the total weight of the catalyst was prepared using 8 g of tungsten oxide powder and 2 g of α-alumina powder, and the catalyst performance evaluation experiment was performed using 0.25 g of the prepared catalyst. Except that was carried out in the same manner as in Example 1.

Example 5

In Example 1, using 8.5 g of tungsten oxide powder and 1.5 g of α-alumina powder, a catalyst having a tungsten oxide content of 85% based on the total weight of the catalyst was prepared, and catalyst performance evaluation experiment was performed using 0.235 g of the prepared catalyst. Except that was carried out in the same manner as in Example 1.

Example 6

In Example 1, using 9 g of tungsten oxide powder and 1 g of α-alumina powder, a catalyst having a tungsten oxide content of 90% based on the total weight of the catalyst was prepared, and a catalyst performance evaluation experiment was performed using 0.222 g of the prepared catalyst. Except that was carried out in the same manner as in Example 1.

Example 7

In Example 1, a catalyst having a tungsten oxide content of 95% based on the total weight of the catalyst using 9.5 g of tungsten oxide powder and 0.5 g of α-alumina powder was prepared, and a catalyst performance evaluation experiment was performed using 0.211 g of the prepared catalyst. The same procedure as in Example 1 was conducted except for the one.

Comparative Example 1

An ammonium metatungstate aqueous solution was prepared from a tungsten raw material at a concentration of 2 mmol / g. As the refractory inorganic material, α-alumina SA5205 (Saint-Gobain Norpro) was pulverized and filtered into a mesh to be used in a size of 200 μm. 10 g of aqueous ammonium metatungstate solution was added to 10 g of α-alumina, followed by evaporation to dryness by heating and stirring on a water bath. It was dried at 120 ° C. for 18 hours, and then calcined at 650 ° C. for 2 hours in an air atmosphere. The tungsten oxide content of the catalyst thus obtained accounted for 20.21% of the total weight of the catalyst. 0.99 g of the prepared catalyst was charged, and a catalyst performance evaluation experiment was performed in the same manner as in Example 1.

Comparative Example 2

In Comparative Example 1, 10 g of ammonium metatungstate aqueous solution was added to 15 g of α-alumina to prepare a catalyst having a tungsten oxide content of 23.45% based on the total weight of the catalyst, and a catalyst performance evaluation experiment was performed using 0.85 g of the prepared catalyst. It carried out similarly to the said Comparative Example 1 except having done one.

Conversion rate, selectivity, and one-pass yield of the catalysts prepared in Examples and Comparative Examples were determined by the following equation in consideration of by-products and are shown in Table 1 below.

Conversion (mol%) = (moles of reacted raw materials / moles of supplied raw materials) × 100

Selectivity (mol%) = (moles of each product / moles of reacted raw materials) × (number of carbon atoms of each product / number of carbon atoms of supplied raw materials) × 100

One-pass yield (mol%) = (moles of each product / moles of feedstock) x (number of carbon atoms of each product / carbon atoms of feedstock) × 100

division Reaction temperature (℃) Conversion rate (mol%) Selectivity (mol%) One pass yield (mol%) TPAL PTAL TPAL PTAL Example 1 520 32.5 49.4 7.0 16.1 2.3 550 55.6 46.4 5.4 25.8 3.0 580 80.9 41.1 4.5 33.2 3.7 Example 2 520 30.0 62.0 6.6 18.6 2.0 550 56.1 61.0 5.3 34.2 3.0 580 82.3 52.4 4.3 43.1 3.6 Example 3 520 27.6 70.6 6.1 19.5 1.7 550 49.8 71.1 5.2 35.4 2.6 580 78.1 61.2 4.4 47.9 3.4 Example 4 520 39.5 70.1 4.7 27.6 1.9 550 52.6 76.2 3.8 40.1 2.0 580 72.5 70.1 3.7 50.8 2.7 Example 5 520 46.5 62.2 4.3 28.9 2.0 550 63.6 70.8 3.9 45.0 2.5 580 81.5 62.1 3.4 50.6 2.7 Example 6 520 60.8 46.7 3.9 28.4 2.4 550 72.8 68.5 3.7 49.9 2.7 580 87.0 61.7 3.1 53.7 2.7 Example 7 520 87.3 42.4 3.1 37.2 2.7 550 93.0 54.0 2.9 50.2 2.7 580 97.7 50.4 2.1 49.2 2.1 Comparative Example 1 520 19.9 59.1 6.1 11.8 1.2 550 31.3 66.0 5.7 20.7 1.8 580 48.2 65.1 5.4 31.3 2.6 Comparative Example 2 520 12.1 51.6 8.4 6.2 1.0 550 20.0 57.2 7.5 11.4 1.5 580 32.3 58.9 6.7 19.0 2.2  TPAL: terephthalaldehyde, PTAL: p-tolualdehyde

Through the Table 1 and Figure 1, the content of the catalyst active ingredient tungsten oxide per weight of the catalyst as compared to the catalyst of Example 1 prepared according to the present invention and the catalyst of Comparative Examples 1 to 2 prepared by the general impregnation method Despite the similarity, the conversion was increased, and the catalysts of Examples 2 to 7 prepared by increasing the content of tungsten oxide as an active ingredient in the total catalyst by milling showed that the conversion and TPAL selectivity were increased. Therefore, the catalyst prepared according to the preparation method of the present invention was found to be advantageous in obtaining a high yield of terephthalaldehyde as the conversion rate increases as the content of the active ingredient for the entire catalyst increases despite the same amount of the active ingredient.

As described above, according to the present invention, it is possible to uniformly mix the catalyst components, to easily control the content of tungsten oxide as a main component, and to prepare a catalyst having a high content of tungsten oxide, in particular, to select an aromatic aldehyde. It is possible to provide a catalyst for partial oxidation of methylbenzenes, which can improve the yield of aromatic aldehydes per unit weight of the catalyst and the catalyst, which has the effect of ultimately reducing the volume of the reactor.

Although described in detail above with reference to the specific embodiments of the present invention, it will be apparent to those skilled in the art that various changes and modifications can be made within the scope and spirit of the present invention, and such variations and modifications belong to the appended claims. It is also natural.

Claims (5)

In the method for producing a methylbenzene partial oxidation catalyst consisting of a tungsten oxide powder and a refractory inorganic powder, characterized in that dry milling is used, The refractory inorganic powder is characterized in that the α-alumina, silica, titania, zirconia, silicon carbide, calcium aluminate or magnesium aluminate  Method for producing a catalyst for partial oxidation of methylbenzenes. The method of claim 1, The method for producing the methylbenzene partial oxidation catalyst (a) mixing a catalyst component consisting of a tungsten oxide powder and a refractory inorganic powder, and (b) Dry milling the powder mixed in the step (a) Method for producing a methylbenzene partial oxidation catalyst comprising a. The method of claim 1, The tungsten oxide powder is a method for producing a methylbenzene partial oxidation catalyst, characterized in that 20 to 98% by weight based on the total catalyst component mixture consisting of tungsten oxide powder and refractory inorganic powder. The method of claim 2, The dry milling step (b) is a method for producing a methylbenzene partial oxidation catalyst, characterized in that the milling time is 0.5 to 48 hours. It consists of tungsten oxide powder and refractory inorganic powder, The refractory inorganic powder is characterized in that the α-alumina, silica, titania, zirconia, silicon carbide, calcium aluminate or magnesium aluminate Catalyst for partial oxidation of methylbenzenes.

Images