JPH0938494A - Catalyst compacting method using alumina as binder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To compact oxide catalyst powder treated with sulfuric acid and useful as a solid acid catalyst used in various acidic catalytic reactions without reducing the activity of the catalyst. SOLUTION: When an oxide catalyst compact treated with sulfuric acid radicals is produced, a metal hydroxide and boehmite are compacted and the resultant compact is fired at 300-500 deg.C, treated with sulfuric acid radicals and fired at 400-700 deg.C. By this firing, the resultant catalyst is activated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst molding method using alumina as a binder, and more particularly to a molding method for industrial use of a sulfate group-treated metal oxide used as a solid acid catalyst.

[0002]

2. Description of the Related Art Generally, in industrial use, a powdery catalyst is often used by filling it into an actual apparatus after forming a columnar, spherical, granular, or the like molded body with an appropriate binder. The molding is relatively inert so as not to affect the original catalytic activity, and dehydrates and condenses by heating to form a strong bond, and is porous and has a large surface area so that the contact efficiency with the reactant is high. Materials having characteristics such as large size have been used as a binder. Typical binders having such characteristics include alumina and silica. Examples of the molding method include an extrusion molding method, a tumbling granulation method, and an oil dropping method, which have been used for a long time and are well known to those skilled in the art.

[0003]

It has been found that a sulfate treatment catalyst for metal hydroxide can be applied to various acidic catalytic reactions as a solid acid catalyst, and the reaction is being actively studied. However, conventionally, these reactions have been studied in the powder state. When the catalyst is used by filling it in a usual industrial actual equipment, for example, a fixed bed flow type reactor, the powder causes problems of fluidization and differential pressure, and therefore it is necessary to mold the catalyst into an appropriate size.

However, it has been found that when the powdered metal hydroxide sulfate group catalyst is molded using alumina as a binder according to a conventional method well known to those skilled in the art, the activity is extremely low. It was considered that the sulfate-treated catalyst of metal hydroxide was very unstable and the active structure was destroyed during the molding operation.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the problem that the sulfate-treated catalyst of metal hydroxide loses its activity during the molding operation, and as a result, In the molding using alumina as a binder, after molding using a boehmite powder and a metal hydroxide powder as raw materials and pre-baking the molded body at a temperature of 300 ° C to 500 ° C,
The inventors have found that a good molded catalyst can be obtained without loss of activity by performing the sulfuric acid radical treatment. Hereinafter, the present invention will be described in detail.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION A sulfate group-treated metal oxide catalyst obtained by firing a sulfate group-treated metal hydroxide was first prepared by Arata and Hino et al. In terms of titanium hydroxide, zirconium hydroxide, hafnium hydroxide, tin hydroxide and water. It was discovered from the fact that strong acid points are developed by treating various metal hydroxides such as lead oxide and iron hydroxide with sulfuric acid (Japanese Patent Publication Nos. 59-6181 and 59-40056). . If necessary, a metal may be supported to improve the stability of catalytic activity (Japanese Patent Laid-Open Nos. 61-68137 and 61-68138).
No.).

Thereafter, these sulfate-treated metal oxide catalysts can be applied as solid acid catalysts to various acidic catalytic reactions such as isomerization reaction, alkylation reaction, disproportionation reaction, decomposition reaction, polymerization reaction and esterification reaction. And its applications are being actively studied.

The outline of the prior art of the method for treating a metal hydroxide with a sulfate group is as follows. A water-soluble metal salt is used as a raw material to obtain a metal hydroxide by hydrolysis, and the metal hydroxide is treated with sulfuric acid to obtain a sulfate group. After being supported, it is finally calcined at an appropriate temperature to obtain an active sulfate group-treated metal oxide catalyst. This will be described in more detail below.

The preparation of the metal hydroxide is as follows. When an alkaline aqueous solution is added to an aqueous solution in which a target metal salt is dissolved to raise the pH, insoluble metal hydroxide is produced and precipitation occurs. The precipitate formed is filtered, washed thoroughly with distilled water until free of anions, and dried.

The alkaline aqueous solution is preferably one that does not finally remain on the catalyst after being dried and calcined, and an aqueous solution of an alkali metal or alkaline earth metal hydroxide is not preferred. Most preferred is an aqueous ammonia solution that decomposes by drying and / or calcination and does not remain on the catalyst. It is also possible to use an aqueous solution containing an ammonia precursor such as urea or hexamethylenetetramine, which decomposes by heating to produce ammonia.

As the metal salt, any water-soluble metal salt can be used. For example, in the case of titanium hydroxide, the titanium salt includes titanium chloride, titanium nitrate, tetraisopropoxytitanium and the like.
In the case of zirconium hydroxide, zirconium oxychloride,
Examples include zirconium oxysulfate, zirconium oxynitrate, zirconium chloride, zirconium nitrate and the like. In the case of hafnium hydroxide, there are hafnium chloride, hafnium nitrate and the like. In the case of tin hydroxide, there are tin chloride, tin nitrate and the like.

The precipitate formed is left to stand for about 1 day to be aged and then filtered. The filtered precipitate is washed with distilled water until anions such as chloride ion and nitrate ion of the salt used in the filtrate do not flow out.

After washing, at a temperature of 100 to 150 ° C. for 1 to 2
A metal hydroxide is obtained after drying for 0 hours.

After drying, if necessary, metal loading can be carried out. The supported metal is preferably a Group VIII metal having high hydrogen activation ability. Fe, Co, Ni, Ru, Rh, Pd, Ir, Pt as the Group VIII metal
And the like. The metal plays a role of spillover in which hydrogen molecules are activated on the metal surface and dissociated into hydrogen atoms to supply active hydrogen atoms to the catalyst surface. It is said that the spillover hydrogen has a function of suppressing the decomposition reaction and removing the coke precursor on the catalyst in relation to the isomerization reaction at the acidic point.

Among the Group VIII metals, Pd and Pt have the highest spillover ability. Since other metals have a slightly low activity, they require a large supported amount, and a large supported amount has an adverse effect such as a decrease in acidic activity. The amount of supported metal is 0.01 to 5%, more preferably 0.05 to 3%.

The method of supporting the metal is typically a method known to those skilled in the art such as an impregnation method in an aqueous solution and an ion exchange method, but any method can be used as long as it can be highly dispersed and uniformly supported on the catalyst. .

The metal compound used for supporting may be any of various water-soluble salts such as chloride, bromide, iodide, sulfate, nitrate and ammine complex salt. The metal hydride supported may be subjected to the following sulfate group treatment. That is, the activity is almost the same no matter which of the order of the sulfate radical treatment and the metal hydride loading is performed first.

Next, a sulfate group treatment is performed. The sulfate group treatment is carried out by adding a sulfate salt dissolved in water to the powder obtained by the above operation, allowing to stand, and filtering or evaporating to dryness. Depending on the required activity, the concentration of the sulfate solution used is in the range of 0.1 to 10N. The concentration of the sulfate solution also depends on the type of metal hydroxide used. For example, zirconium hydroxide is said to have the highest acidity of about 1N, and hafnium hydroxide is said to have the highest acidity of about 2N. The olefin isomerization preferably has a low acidity, and the paraffin isomerization requires a high acidity. Since the preferable acidity varies depending on the type of reaction, an appropriate sulfate group concentration range is selected according to the reaction.

As the compound having a sulfate group, various water-soluble sulfates such as sulfuric acid, ammonium sulfate, sodium sulfate and potassium sulfate can be used. Particularly preferred are sulfuric acid and ammonium sulfate, which leave no metal on the catalyst after the calcination treatment.

After standing for a while, the mixture is filtered or evaporated to dryness. When filtered, the unadsorbed sulfate radicals are washed away,
Sulfate content is slightly reduced. Evaporation to dryness is from room temperature to 9
It evaporates water at a temperature of about 0 ° C, and most of the sulfate radicals in the solution are carried by the molded body. After filtration or evaporation to dryness, it is dried. For example, the drying is 110 ° C. for 1 to 20
Do time.

Finally, the catalyst is activated through a calcination process. Although the firing temperature varies depending on the metal hydroxide, 400
The temperature range is up to 700 ° C. During the process of dehydration condensation of the metal hydroxide to form the metal oxide by firing, the sulfate radicals are incorporated into the metal oxide, exhibiting strong electron-withdrawing property and removing the hydroxyl group pront on the metal oxide. It is presumed that it is activated and its acid strength is increased.

The powdery catalyst thus prepared was molded by a conventional extrusion molding method well known to those skilled in the art. That is, a sulfuric acid-treated zirconia catalyst powder, which is a typical sulfate group-treated metal oxide catalyst, is mixed with boehmite powder and made to have fluidity so as to have fluidity, and extruded from a hole of about 1 mm to form a columnar shape. After drying at a temperature for 2 hours, it was baked at a temperature of 600 ° C. for 3 hours to obtain a columnar molded catalyst. When the activity of the isomerization reaction of this catalyst was measured as shown in Comparative Examples below, the activity was about 20% of that of the original catalyst powder.
It showed only a fraction of the activity. It is considered that, in the sulfate group treatment catalyst of metal hydroxide, the special structure containing sulfate group plays an important role in the expression of the catalytic activity, but the water used during the molding operation destroys the structure. I presume.

According to the molding method of the present invention, boehmite powder as a raw material and a metal hydroxide are used for molding, and a molded body is molded into 300
It is characterized in that the sulfate group treatment is carried out after pre-baking at a temperature of from ℃ to 500 ℃. In this method, the sulfate group treatment is carried out at the end of the molding operation to avoid the destruction of the special structure containing the sulfate group, so that it is considered that a good molded catalyst can be obtained without losing the activity.

Alumina raw materials are usually in the form of powder and are commercially available as alumina powder or solution in the form of alumina sol, and the structure thereof is AlO (OH) ₂ (AlOOH) _n Al.
It has a structure called boehmite in which aluminum hydroxide represented by a chemical formula of (OH) ₂ (n is 1 to 100) is low-polymerized. Boehmite is stabilized with acids such as acetic acid and hydrochloric acid,
It is marketed in a state in which it is prevented from polymerizing and polymerizing further.

A method of molding using metal hydroxide powder and boehmite as a binder is well known to those skilled in the art, and for example, Granulation Handbook (Ohm Co., 1991) 657.
~ Page 671. Examples of the method include an extrusion molding method, a tumbling granulation method, an oil dropping method, and the like, and a columnar, spherical, granular, or other molded body can be manufactured by these methods.

The shaped body is dried and then fired to maintain its strength. Boehmite is dehydrated and condensed by heating,
As it crystallizes, its crystal form changes. At the conventional calcination temperature of 300 ° C. to 700 ° C., γ-alumina or η-alumina having a high surface area is obtained, which has a high surface area and is porous, has high strength, and shows good performance as a binder. 70
At a temperature higher than 0 ° C., it becomes inactive as low surface area α-alumina. In this respect, in the temperature range of 300 to 500 ° C., it partially dehydrates and condenses and crystallizes, so that the strength increases and it becomes insoluble in water, but it still has a hydroxyl group,
It is considered that it is not completely alumina. 300
At a temperature of lower than 0 ° C, dehydration condensation does not occur only by drying water, and it is considered that addition of water causes powdering and breakage.

On the other hand, the metal hydroxide, like boehmite, is dehydrated and condensed by heating and crystallized, and its crystal form is changed. The metal hydroxide becomes an oxide at a temperature higher than 500 ° C, and is not highly activated because the sulfuric acid radical does not enter between the bonds in the subsequent sulfuric acid treatment, and the metal hydroxide is often present at a low temperature of 500 ° C or lower. Remainingly, it is considered that the effect of high activation by the treatment with sulfate group is large. From the above, the firing temperature of the molded body in the present invention is preferably 300 ° C or higher and 500 ° C or lower. The main firing operation is referred to as pre-firing in this specification.

Regarding the firing time, the longer the time, the higher the strength. However, if the firing time is too long, a part of the metal hydroxide becomes an oxide and the activity is lowered. If it is too short, it does not have sufficient strength, so it will be pulverized in the next operation. Therefore, a firing time of 1 to 10 hours is appropriate.

After pre-firing, a molded body having an appropriate strength that does not powder even when water is added is subjected to sulfate treatment. The method of treating the sulfate radical is exactly the same as the procedure for the powder. Further, the drying and firing steps after the treatment with sulfuric acid radical are exactly the same as those for the powder. Incidentally, the metal loading operation, even if using the metal hydroxide powder before molding, or using the molded body before sulfate radical treatment, almost similar activity can be obtained,
It is more preferable to perform the treatment on the molded body before the treatment with sulfuric acid radical, since the activity is slightly higher.

[0030]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples without departing from the gist of the present invention.

Example (1) Preparation of catalyst A Zirconium hydroxide was synthesized as follows. Dissolve 100 g of zirconium oxychloride in 760 ml of ion-exchanged water, add 28% ammonia water while stirring,
Adjust to pH 10. The precipitate formed is filtered off, and the filtrate is washed with ion-exchanged water until no chloride ion is detected.
After washing, it is dried at 110 ° C. for 20 hours to obtain zirconium hydroxide.

26.4 g of zirconium hydroxide and 20 g of vermite were mixed, kneaded well with 40 g of water, extruded through a hole having a diameter of 1 mm, and dried at 120 ° C. for 2 hours to obtain a columnar molded body. This is referred to as a molded body a. Next, the molded body a was baked at 400 ° C. for 3 hours. This is referred to as a molded body A. 30 g of the molded product A was placed in a beaker, and 75 ml of an aqueous hexachloroplatinic acid solution containing 0.2% of platinum was added to the beaker.
Is added. Molded product A maintained a solid state and did not change. After evaporating to dryness, it is dried at 110 ° C for 20 hours, and 0.5%
A platinum-supported molded catalyst was obtained.

Next, sulfate radical treatment was performed. 25 ml of IN sulfuric acid was added to 10 g of 0.5% platinum-supported molded catalyst,
Dry at room temperature.

After further drying at 110 ° C. for 2 to 3 hours, it is baked at 600 ° C. for 3 hours. This is designated as catalyst A. (2) Preparation of catalyst B In the preparation of catalyst A, the order of operations of platinum loading and sulfate radical treatment is exchanged, the sulfate radical treatment is carried out before platinum loading, and other operations are performed in exactly the same manner. This is designated as catalyst B. (3) Preparation of catalyst C In the preparation of catalyst A, only IN ammonium sulfate was used instead of IN sulfuric acid, and other operations were performed in exactly the same manner. This is designated as catalyst C. (4) Preparation of catalyst D 10 g of zirconium hydroxide obtained in the preparation of catalyst A is placed in a beaker, and 25 ml of hexachloroplatinic acid aqueous solution containing 0.2% of platinum is added thereto. After evaporation to dryness,
After drying at 110 ° C. for 20 hours, 0.5% platinum-supported zirconium hydroxide was obtained. 5.3 g of 0.5% zirconium hydroxide supporting platinum and 4 g of vermite were mixed, kneaded well with 8 g of water, extruded through a hole having a diameter of 1 mm, and dried at 120 ° C. for 2 hours to obtain a columnar molded body. Then, it was baked at 400 ° C. for 3 hours. This is referred to as a molded body b.

12.5 ml of IN sulfuric acid is added to 5 g of the molded body b and dried at room temperature. After further drying at 110 ° C. for 2 hours, baking is performed at 600 ° C. for 3 hours. This is designated as catalyst D.

Comparative Example (1) Preparation of Catalyst E 10 ml of IN sulfuric acid was added to 4 g of 0.5% platinum-supported zirconium hydroxide obtained in the section of preparation of catalyst D, and the mixture was dried at room temperature. After drying, it is baked at 600 ° C. for 3 hours. This is designated as (powder) catalyst e. (Powder) 2.64 g of catalyst e and 2 g of vermite were mixed, kneaded well with 4 g of water, extruded through a hole having a diameter of 1 mm, and dried at 120 ° C. for 2 hours,
A columnar molded body was obtained. This is referred to as a molded body e. After drying 6
Bake at 00 ° C for 3 hours. This is designated as catalyst E. (2) Preparation of catalyst F 10 ml of IN sulfuric acid was added to 4 g of 0.5% platinum-supported zirconium hydroxide obtained in the preparation of catalyst D, and the mixture was dried at room temperature. This is designated as catalyst f. 2.64 g of catalyst f and 2 g of boehmite were mixed, 4 g of water was added and kneaded well,
It was extruded from a hole having a diameter of 1 mm and dried at 120 ° C. for 2 hours to obtain a columnar molded body. After drying, it is baked at 600 ° C. for 3 hours. This is designated as catalyst F. (3) Preparation of catalyst G In preparation of catalyst A, pre-baking of the molded body a is performed at 550 ° C. instead of 400 ° C., and other operations are performed in exactly the same manner. This is designated as catalyst G. (4) Preparation of catalyst H In preparation of the catalyst A, pre-baking of the molded body a was performed at 250 ° C instead of 400 ° C. This was powdered when water was added, and the next operation could not be performed.

Experimental Example Table 1 shows the results of the isomerization reaction using catalysts A, B, C and D using pure n-hexane as a raw material. The reaction conditions are a temperature of 200 ° C., a pressure of 10 Kg / cm ² , a liquid space velocity of 10 g / h · g-cat (excluding alumina), and a hydrogen ratio of 5
It is mol / mol.

[0038]

[Table 1]

Comparative Example Table 2 shows the results of the isomerization reaction using catalysts E, F and G using n-hexane as a feed oil. For reference, the results of (powder) catalyst e are also shown in Table 2. The reaction condition is a temperature of 20.
0 ° C., pressure 10 kg / cm ² , liquid space velocity 10 g / h.
g-cat, hydrogen ratio 5 mol / mol.

[0040]

[Table 2]

[0041]

EFFECTS OF THE INVENTION According to the method for molding a catalyst using alumina as a binder of the present invention, the sulfuric acid-treated oxide catalyst, which has been conventionally used in powder form, can be used as a molded body by filling it in an industrial apparatus. It was

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Fumio Kumada 3-21-19 Okubo, Konan-ku, Yokohama-shi, Kanagawa

Claims (2)

[Claims] 1. A method for producing a sulfate group-treated metal oxide catalyst molded body, which comprises molding using a metal hydroxide and boehmite, pre-baking the molded body at a temperature of 300 ° C. to 500 ° C., and then sulfuric acid. Catalyst molding method using alumina as a binder characterized by performing root treatment 2. The catalyst molding method according to claim 1, wherein the raw material of sulfate is sulfuric acid or ammonium sulfate.