KR980009114A - Method for producing porous composite oxide - Google Patents

Abstract

The present invention relates to a method for producing a porous composite oxide. Preparing a solution containing a silicon oxide source and a solution containing an aluminum oxide source; slowly adding one solution of the solution to another solution while stirring; The porous composite oxide prepared through the steps of preparing a clear sol by adding hydrochloric acid to the mixed solution obtained in the above step and then forming a gel by administering sodium hydroxide and allowing the gel to be placed in a reaction vessel and reacting at a high temperature and a high pressure, It is well-suited for use as a carrier since the fine pores are formed abundantly and the pore size distribution is uniform.

Description

Method for producing porous composite oxide

FIG. 1 is a graph showing a distribution of volume according to a starter key of a composite oxide produced according to an embodiment of the present invention. FIG.

FIG. 2 is a graph showing the distribution of pore volume versus pore size of the composite oxide prepared according to the conventional method.

[TECHNICAL FIELD OF THE INVENTION AND RELATED ART OF THE SAME]

The present invention relates to a method for producing a porous composite oxide, and more particularly, to a method for producing a porous composite oxide, which is suitable for use as a support because of its large pore size and uniform distribution, .

Currently, the development of the chemical industry is accompanied by the development of various catalysts. Catalysts are an essential element in the synthesis, degradation, and modification of materials, and the importance thereof is clear.

As such a catalyst, fine particles of a metal or other component are generally used. The method of use is various, but usually it is generally carried on a carrier.

Such a carrier generally does not have reactivity per se, but in particular, it is required that the micropores are formed abundantly. This is because, in order to facilitate the catalytic reaction, the space in which the catalytic component, which is a particulate matter, and the catalytic component, which is a reactive substance, and the reactive substance can contact each other needs to be large.

Currently commonly used carriers include silica, alumina, alumino silicate silicate), zeolite, and activated carbon. Among them, aluminosilicate has properties of pores of various sizes and is widely used as a carrier.

The aluminosilicate is generally obtained by dissolving a water-soluble aluminum oxide source and a silicon oxide source in water, followed by heating. However, since the aluminosilicate produced according to the conventional method has a small pore size and the catalyst is carried on the surface thereof, the aluminosilicate prepared according to the catalyst method has a small pore size, and the catalyst is supported on the surface thereof, There is a shortcoming that there is not enough room to create. In order to achieve a smooth catalytic reaction, it is necessary to develop a carrier capable of further increasing the contact area between the reactant and the catalyst. The aluminosilicate produced by the conventional method does not satisfy such an increasing demand. On the other hand, the pores of the carrier are required to have pores having diameters of various sizes uniformly distributed as a space in which the catalyst microparticles can be carried. However, the aluminosilicate produced by the conventional method has a problem that the distribution of the pore size is uneven and it is difficult to support the catalyst microparticles of various sizes.

[Technical Problem]

SUMMARY OF THE INVENTION The present invention provides a method for producing a porous composite oxide in which fine pores are formed so as to be suitable for use as a carrier and the distribution of pore volume is uniform according to pore size.

[Structure and operation of the invention]

According to an aspect of the present invention, there is provided a method of preparing a solution containing a silicon oxide source and a solution containing an aluminum oxide source, comprising the steps of gradually adding one solution of the solution to another solution while stirring the mixture, Preparing a clear sol by adding hydrochloric acid to the solution, and then forming a gel by administering sodium hydroxide; and allowing the gel to react in a reaction vessel at a high temperature and a high pressure. Is provided

Hereinafter, the present invention will be described in more detail through a process for producing an aluminosilicate of a composite oxide.

First, the water-soluble silicon oxide source and the water-soluble aluminum oxide source are dissolved in water in a separate vessel.

In the present invention, as the silicon oxide source, a silicate salt is preferable, and a sodium silicate is more preferable. The aluminum oxide source is preferably an aluminate salt, more preferably a sodium dicumylate. If the reactants are slow in dissolving in water, they can be heated. Particularly, it is appropriate to heat and dissolve the silicon oxide source because the silicon oxide source and the water have insufficient solubility in water. The heating temperature varies depending on the solubility and properties of the reactants to be used, and is usually from 50 to 60 캜.

When each solution in which the silicon oxide source and the aluminum oxide source are dissolved is prepared, these solutions are mixed. The content ratio of the silicon oxide source to the aluminum oxide source is preferably such that the molar ratio of silicon to aluminum is 1 to 3.

On the other hand, one of the two solutions to be mixed should be slowly added to the other solution so that the silicon oxide source and the aluminum oxide source are uniformly mixed. It is also necessary to heat and stir the solution to be administered during the mixing of the solution.

When the mixing of the two solutions is complete, hydrochloric acid is added until a clear transparent sol is obtained. Subsequently, sodium hydroxide is administered, and the sol is converted into a gel. Here, sodium hydroxide acts to smoothly and uniformly react the silicon oxide source dissolved in water and the aluminum oxide source. Hydrochloric acid and sodium hydroxide are preferably administered in the form of diluted solutions, respectively, and the pH of the reaction solution is preferably 3 to 12.

Finally, when the gel is heated and reacted, aluminosilicate having fine pores is produced. The reaction is completed after 1 to 10 hours at a pressure of 100 to 1200 psi and a temperature of 100 to 300 캜. Preferably, the pressure is 100 to 200 psi and the temperature is 100 to 150 deg.

Hereinafter, the present invention will be specifically described with reference to examples and comparative examples, but the present invention is not necessarily limited thereto.

[Example 1]

98.4 g of sodium di-silicate (Na2SiO3) was added to 150 ml of distilled water, and the solution was completely dissolved by keeping it at a temperature of 55 캜. In a separate container, 152.5 g of sodium di-aluminate (NaALO2) was dissolved in 700 ml of distilled water. Sodium di-aluminate solution was slowly administered to the sodium silicate solution. At this time, the mixed solution was stirred and simultaneously heated to maintain the temperature at around 55 ° C. After mixing was complete, 6N HCl was administered until the reaction mixture was clear. To the clear solution, 6N NaOH was added until the pH reached 10, and then the gel was allowed to stand for 60 minutes. The gel was placed in a reactor and reacted at 100 ° C for 24 hours. The reaction product was filtered using a vacuum pressure-reducing apparatus, and then dried at 100 ° C for 24 hours to prepare powdered aluminosilicate. The surface area and pore size distribution of the prepared powder were measured. The BET surface area was 135 (m² / g) and the distribution of the pore volume according to the pore size was uniform throughout. .

[Example 2]

Powdered aluminosilicate was prepared in the same manner as in Example 1 except that 6N NaOH was added to adjust the pH to 7 and the reaction conditions were 150 캜 and 150 psi.

The surface area and the pore distribution of the prepared powders were measured. The BET area was 135 (m² / g) and the distribution of the pore volume according to the pore size was uniform as a whole (FIG.

[Example 3]

Powdered aluminosilicate was prepared in the same manner as in Example 1, except that 6N NaOH was added to adjust the pH to 3 and the reaction conditions were set at 265 DEG C and 1100 psi.

The surface area and pore distribution of the prepared powders were measured. The BET surface area was 205 (m² / g) and the distribution of pore volume according to pore size was uniform throughout (Fig. 1, c).

[Comparative Example]

Powdered aluminosilicate was prepared in the same manner as in Example 1 except that HC1 and NaOH were not added, and the BET surface area and pore distribution were measured.

As can be seen from the results of the examples and the comparative examples, the aluminosilicate prepared according to the present invention has a BET surface area much larger than 100 (m² / g), whereas the aluminosilicate prepared according to the conventional method has a BET The surface area was not good as 3.3 (m² / g). From the viewpoint of the pore distribution, the aluminosilicate of the present invention has a uniform pore volume change depending on the pore size (FIG. 1), whereas the conventional aluminosilicate has a very uneven distribution of the pore volume according to the pore size (FIG. 2).

[Effects of the Invention]

As can be seen from the above, the porous composite oxide produced according to the present invention has an abundance of micropores, and the distribution of the pore size is well-defined and suitable for use as a carrier.

Claims (9)

Preparing a solution containing a silicon oxide source and a solution containing an aluminum oxide source; Stirring one solution of the solution while another solution is being administered in another solution; Preparing a clear sol by adding hydrochloric acid to the mixed solution obtained in the above step, and then adding sodium hydroxide to form a gel; And introducing the gel into a reaction vessel and reacting at a high temperature and a high pressure. The method of claim 1, wherein the silicon oxide source and the aluminum oxide source are administered such that the molar ratio of aluminum to silicon is 1 to 3. The method of claim 1, wherein the silicon oxide source is a silicate salt. 4. The method of claim 3, wherein the silicate salt is a sodium di-silicate. The method for producing a porous composite oxide according to claim 1, wherein the aluminum oxide source is an aluminate salt. The method of claim 5, wherein the aluminum salt is sodium dibutylaluminate. The method of claim 1, wherein the sodium hydroxide is administered so that the pH of the sol is from 3 to 12. The method of claim 1, wherein the reaction is performed at a temperature of 100 to 300 ° C and a pressure of 100 to 1200 psi. The process for producing a porous composite oxide according to claim 8, wherein the temperature is 100 to 150 ° C and the pressure is 100 to 200 psi. ※ Note: It is disclosed by the contents of the first application.