KR100567106B1 - Synthesis of Cubic Mesoporous Molecular Sieve - Google Patents

Abstract

The present invention relates to a novel process for the preparation of mesoporous molecluar sieve materials having pore arrays of Ia3d structures. In the present invention, a cationic surfactant and a neutral surfactant are used as a structure-directing agent, and the silica source is a colloidal silica Ludox HS40 (trade name of DuPont) and sodium hydroxide. Sodium silicate aqueous solution prepared by using the present invention was developed, and it was easier and more reproducible than the existing method by developing a new preparation method that controls the reaction equilibrium by controlling the pH of the reactants during hydrothermal reaction. Yields could also be significantly increased. In addition, the method of the present invention can also prepare a molecular sieve material in which the other metal elements such as aluminum or titanium other than silicon in the skeleton of the mesoporous molecular sieve material can be prepared, and the molecular sieve material using various salt effects during the manufacturing process The thermal stability and hydrothermal stability of can be significantly improved.

Mesoporous molecular sieve, cationic surfactant, neutral surfactant, colloidal silica, hydrothermal reaction

Description

Method for producing cubic mesoporous molecular sieves {Synthesis of Cubic Mesoporous Molecular Sieve}

1 is MCM-48 material prepared in Example 1 of the present invention, that is, 5 SiO ₂ : 0.82 HTMABr: 0.18 C ₁₂ H ₂₅ O (C ₂ H ₄ O) ₄ H: 1.25 Na ₂ O: 400 H ₂ O Characteristic X-ray diffraction graph of MCM-48 material through steps (A)-(G) at 100 ° C. using a reaction mixture having a molar composition of.

FIG. 2 is an adsorption-desorption isotherm of nitrogen obtained at liquid nitrogen temperature for the MCM-48 material of FIG. 1.

FIG. 3 is a pore size distribution curve obtained by BJH ((Barrett-Joyner-Halenda) method from the adsorption-desorption isotherm of nitrogen shown in FIG. 2.

Figure 4 in the production method of the present invention, the step (E), that is, the first hydrothermal reaction after cooling the reaction mixture to room temperature after omission of the hydrothermal reaction by adjusting the pH of the mixture using an acid again and hydrothermal reaction at 100 ℃ X-ray diffraction graph of the materials prepared through. (a) is x = 0.05, (b) is 0.11, (c) is 0.18, and (d) is 0.25.

5 is a step by step while hydrothermally reacting a reaction mixture having a molar composition of 5 SiO ₂ : 0.82 HTMABr: 0.18 C ₁₂ H ₂₅ O (C ₂ H ₄ O) ₄ H: 1.25 Na ₂ O: 400 H ₂ O It is an X-ray diffraction graph obtained. (a) is a hydrothermal reaction at 100 ° C. for 2 days, (b) immediately after cooling (a) to room temperature and adjusting the pH to 10 with acetic acid, and (c) (b) again at 100 ° C. After the reaction for 2 days, (d) is the hydrothermal reaction of (b) for 30 days at 100 ℃, (e) is cooled to room temperature (c) again after adjusting the pH to 10 and again 2 days Hydrothermal reaction at 100 ℃.

6 is an X-ray diffraction graph of samples prepared by adding NaCl when synthesizing MCM-48 material. (a) is calcined, and (b) is each of which is placed in distilled water and treated for 12 hours under reflux conditions.

FIG. 7 is an X-ray diffraction graph and aluminum-27 obtained from samples having different amounts of aluminum, which were prepared by adding aluminum to the reaction mixture and then performing hydrothermal reaction until the MCM-48 material was prepared to (c) of FIG. 5. Solid phase NMR spectrum. (a) is Si / Al = 40, (b) is 20, (c) is 10, and (d) is 5.

The present invention relates to a method for producing a cubic mesoporous molecular sieve, and more particularly, it is not only easier and reproducible than the conventional method, but also significantly improves the yield of mesoporous molecular sieve material, and also mesoporous powder. Molecular sieve materials can be prepared by substituting other metal elements such as aluminum or titanium other than silicon in the backbone of its own material, and by using various salt effects during the manufacturing process, the thermal stability and hydrothermal stability of the molecular sieve material can be significantly improved. A method of making cubic mesoporous molecular sieves that can be enhanced.

A new type of mesoporous molecular sieve material, named the M41S family, was produced by Mobil researchers in 1991 and has been published in US Pat. Nos. 5,057,296 and 5,102,643. Research into their own materials is currently active worldwide.

Mesoporous molecular sieve materials, unlike microporous molecular sieve materials with pore sizes of 1.5 nm or less, like conventional zeolite or AlPO-based materials, have mesopores in the range of mesopores (2 Molecular sieve material for adsorption and separation of molecules having a size larger than the pore size of the microporous molecular sieve material, catalytic conversion reaction, and the like, which have been limited in the application of molecular sieve material. Application of is now possible

In the M41S family announced by Mobil, MCM, in which one-dimensional mesoporous pores form a hexagonal array like a honeycomb, MCM-41 material and mesoporous pores are connected by an array of cubic structures of Ia3d. There are -48 substances. Among the mesoporous molecular sieve materials of the M41S group, the potential for application is the MCM-48 material whose pores are arranged in a cubic structure with cubic Ia3d. Deactivation due to pore blockage due to coke formation or sintering of the supported metal is expected to be low. However, the recent research shows that MCM-41 material with straight pore structure is the mainstream among the M41S group, and there are not many studies on MCM-48 material which is expected to be superior to this. to be.

The reason for the lack of research on MCM-48 materials is that the existing methods published by Mobil are not common and they are not reproducible. To date, many researchers have sympathized with this and have been conducting research to develop a method for easy synthesis and reproducibility. For example, in 1996, Huo et al. Reported in Chemistry of Materials, volume 8, page 1147, that MCM-48 materials were prepared using various silica sources and gemini surfactants, and Kim et al. 1998 MCM-48 material can be easily prepared by using Ludox HS40 (trade name of DuPont), a colloidal silica published in Chemical Communication, page 259-260, as a silica source, and adding ethanol to the reaction mixture to hydrothermally react. In particular, it has been reported that the particles of the obtained MCM-48 material are crystals. However, according to the results to date, the reason for the lack of reproducibility of the synthesis of MCM-48 is that the MCM-48 is not a thermodynamically stable phase, and hexagonal structure or irregular mesoporous molecular sieve material is formed at the beginning of the reaction in the synthesis solution. This is because the MCM-48 material is formed, and over time, the phase transition occurs to a thermodynamically stable lamellar structured material. That is, the lack of reproducibility is because the manufacturing methods for the existing MCM-48 are dynamically controlled. From this point of view, if a method for thermodynamically controlling the preparation of MCM-48 is developed, the synthesis method is expected to be easy and reproducible, and the process for improving the properties of MCM-48 material during the manufacturing process, namely, catalytic active point It is expected to be able to increase the stability of hydrothermal properties and increase hydrothermal stability.

Accordingly, an object of the present invention is to improve the shortcomings of the conventional manufacturing method in the mesoporous molecular sieve MCM-48 material to generalize the manufacturing method, and also to increase the yield by reducing the overall manufacturing cost of the three-dimensional array of pores The present invention provides a method for preparing an MCM-48 material, which is a mesoporous molecular sieve material having an Ia3d cubic array.

In addition, another object of the present invention is to adjust the molecular sieve pore size through the control of the production conditions and to improve the hydrothermal stability of the molecular sieve material and the method for producing a material in which various metal elements are substituted in the skeleton of the molecular sieve material. It is to provide a method for producing a cubic mesoporous molecular sieve.

The production method of the present invention for achieving the above object comprises the steps of (A) preparing an aqueous solution by mixing a halogenated alkyltrimethylammonium represented by the formula (1) and a neutral surfactant represented by the formula (2) or (3) as a surfactant; (B) preparing a sodium silicate solution; (C) mixing the aqueous sodium silicate solution of step (B) with the mixed solution of step (A); (D) first hydrothermal reaction of the reaction mixture of step (C); (E) cooling the reaction mixture of step (D) to room temperature, adjusting the pH with an acid, and then performing a second hydrothermal reaction to form a precipitate of the final desired molecular sieve material; (F) filtering, washing and drying the precipitate of the molecular sieve material formed in step (E); And (G) calcining the precipitate precipitated by filtration and washing in step (F).

R ₁ R ₂ R ₃ R ₄ NX

Wherein R ₁ , R ₂ and R ₃ are the same as or different from each other and are CH ₃ or CH ₂ CH ₃ , R ₄ is an alkyl group having 12 to ₂₂ carbon atoms, and X is Cl or Br.

R (OCH ₂ CH ₂ ) nOH

In the formula, R is an alkyl group having 8 to 22 carbon atoms, n is an integer of 3 to 20.

RNH ₂

In the above formula, R is an alkyl group having 8 to 22 carbon atoms.

Hereinafter, the present invention will be described in more detail with reference to the following examples and accompanying drawings.

As described above, the MCM-48 material, which is a mesoporous molecular sieve, is a material having a three-dimensional Ia3d cubic structure, and is expected to have excellent applicability compared to an MCM-41 material having a one-dimensional pore connection structure. Mesoporous molecular sieve material is generally prepared through a liquid crystal template path using a surfactant as a structure-directing agent. In the present invention, the cationic surfactant and the following Chemical Formula 2 and Chemical Formula Neutral surfactants represented by 3 were used.

Formula 1

R ₁ R ₂ R ₃ R ₄ NX

Wherein R ₁ , R ₂ and R ₃ are the same as or different from each other and are CH ₃ or CH ₂ CH ₃ , R ₄ is an alkyl group having 12 to ₂₂ carbon atoms, and X is Cl or Br.

Formula 2

R (OCH ₂ CH ₂ ) nOH

In the formula, R is an alkyl group having 8 to 22 carbon atoms, n is an integer of 3 to 20.

Formula 3

RNH ₂

In the above formula, R is an alkyl group having 8 to 22 carbon atoms.

Examples of the cation-based surfactants include dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, hexadecyltrimethyl ammonium chloride, hexadecyltrimethylammonium bromide, and hexadecyltrimethylammonium bromide. ), Octadecyltrimethylammonium bromide, docosyltrimethylammonium bromide, icocosyltrimethylammonium chloride, or hexadecyltrimethylammonium bromide (HTEABr, hexadecyltrimethylammonium, etc.). As the surfactant of the series, dodecyl polyethylene ether (C ₁₂ H ₂₅ O (C ₂ H ₄ O) nH, n = 3 to 10), hexadecyl polyethylene ether (C ₁₆ H ₃₃ O (C ₂ H ₄ O) nH, n = 3-20), Tritox X-100 (CH ₃ C (CH ₃ ) ₂ CH ₂ C (CH ₃ ) ₂ C ₆ H ₄ O (C ₂ H ₄ O) ₁₀ H), dodecylamine, or hexadecylamine.

Steps (A) to (G) above are methods for preparing MCM-48 material consisting of pure silica backbone used in the context of the present invention.

The amount of the neutral surfactant represented by Formula 2 or 3 based on 1 mole of alkyltrimethylammonium halide represented by Formula 1 in step (A) is preferably 0.03 to 0.95 moles, and the amount of water used The amount is preferably 100 to 1000 moles based on 1 mole of the alkyltrimethylammonium halide represented by the formula (1).

The method for preparing the aqueous sodium silicate solution described in step (B) is Korean Patent Application Nos. 96-52841 and No. 8 pending on November 8, 1996 and February 26, 1997, respectively. Reference is made to 97-6051, which is prepared by mixing a colloidal silica, Ludox HS40 (40 wt% SiO ₂ , DuPont) or fummed silica, with an aqueous sodium hydroxide solution to provide a molar ratio of sodium hydroxide to silica. 0.5 to 0.6 is preferable, and the content of silica (SiO ₂ ) in the finally prepared aqueous sodium silicate solution is preferably about 10 to 20% by weight.

In the step (C) while slowly stirring the surfactant solution of step (A) at room temperature using a magnetic stirring device, the aqueous sodium silicate solution prepared in step (B) is slowly added. In this case, the amount of the aqueous sodium silicate solution added is preferably such that the silica is 3 to 6 mol based on 1 mol of the alkyltrimethylammonium halide represented by the formula (1), and the reaction mixture is added at room temperature after the aqueous sodium silicate solution is added. Stir for 2 hours.

In the step (D), the first hydrothermal reaction temperature is preferably 50 to 120 ° C., and the reaction time is preferably 1 to 6 days.

The acid used in step (E) is preferably acetic acid, hydrochloric acid or sulfuric acid, and the concentration is preferably 1 to 3 M solution. In this step, it is appropriate to adjust the pH of the reaction mixture to 10 to 11, the second hydrothermal reaction temperature is the same as in step (D), and the hydrothermal reaction time is 1 to 10 days. Step (E) may be omitted or performed two or more times as necessary. The precipitate prepared in step (F) is filtered through a filtration device, and then washed 2 to 3 times using distilled water, and dried at about 100 ℃ for 5 to 20 hours.

Finally, step (G) removes the surfactant present in the prepared MCM-48 and calcinates for 1 to 10 hours at a temperature condition between 500 and 900 ° C. under nitrogen, oxygen, or air atmosphere. It is preferable.

1 is a MCM-48 material prepared in Example 1, that is, 5 SiO ₂ : 0.82 HTMABr: 0.18 C ₁₂ H ₂₅ O (C ₂ H ₄ O) ₄ H: 1.25 Na ₂ O: mole of 400 H ₂ O Characteristic X-ray diffraction graph of MCM-48 material through steps (A)-(G) at 100 ° C. using a reaction mixture having a composition. (A) of FIG. 1 is before baking processing, (b) is a case after baking processing. As can be seen in Figure 1, there is only about 5% contraction of the structure before and after the firing treatment, and the X-ray diffraction graphs (211) and (220), (which can be represented by the cubic structure of Ia3d) ( Peaks such as 321, 400, 420, 322, 422, 431, 521, 440, 611, 541, 631, and 543. Shown in the low angle region. As described above, the MCM-48 material prepared by the manufacturing method of the present invention has very excellent structural uniformity in the X-ray diffraction graph of FIG. 1.

FIG. 2 is an adsorption-desorption isotherm of nitrogen obtained at liquid nitrogen temperature for the MCM-48 material of FIG. 1, showing a sudden transition of the adsorption amount of nitrogen near P / P0 of 0.3. The adsorption-desorption isotherm of nitrogen as shown in FIG. 2 is characteristic of mesoporous molecular sieve material as the isotherm of Form IV according to the IUPAC definition. Difference slightly in accordance with the respect to the MCM-48 material prepared in invention such a BET (Brunauer-Emmett-Teller) surface area determined from nitrogen adsorption results (surface area) is a production method, but 1000 ± 100 m ² g ^{- It} has a value of ¹ .

Figure 3 is a pore size distribution curve obtained by the BJH ((Barrett-Joyner-Halenda) method from the adsorption-desorption isotherm of nitrogen shown in Figure 2. According to Figure 3 prepared in Example 1 of the present invention The pore size of one MCM-48 material is 2.4 nm and shows a very narrow pore size distribution curve (line width less than 1 nm at medium height), indicating that the pore structure of the mesoporous molecular sieve material is very uniform.

4 is a step (E) in the manufacturing method of the present invention as shown in Example 2 below, that is, the first hydrothermal reaction of the reaction mixture was cooled to room temperature, the step of hydrothermal reaction again by adjusting the pH of the mixture using an acid X-ray diffraction graphs of materials prepared through hydrothermal reaction at about 100 ° C. are omitted. The reaction mixture has an initial molar composition of 5 SiO ₂ : (1-x) HTMABr: x C ₁₂ H ₂₅ O (C ₂ H ₄ O) ₄ H: 1.25 Na ₂ O: 400 H ₂ O (x is 0 to 0.25) It was prepared to have, and X-ray diffraction graph of the precipitate produced according to the hydrothermal reaction time as shown in FIG. 4 shows that the structure of the mesoporous material obtained by increasing the amount of the neutral surfactant C ₁₂ H ₂₅ O (C ₂ H ₄ O) ₄ H until the initial reaction, that is, until 4 days at 100 ℃ elongated the hexagonal arrangement It can be seen that MCM-41 having a cubic structure according to the present invention in MCM-41 having a structure of lamellar material having a layered structure at x = 0.25. For this reason, as described above, the structure of the mesoporous molecular sieve material is changed by the liquid crystal structure of the surfactant, wherein the degree of interaction between the silicate anion and the head of the surfactant plays a very important role. . When neutral surfactants are added as compared to the case of using only cationic surfactants, the degree of interaction between the silicate anions and the heads of the entire surfactants is weakened, resulting in a transition of the structure shown in FIG. 4. will be. However, as shown in FIG. 4, even when the MCM-48 material according to the present invention is obtained by controlling the amount of the neutral surfactant, the transition to the layered structure occurs as the hydrothermal reaction time elapses. This phenomenon generally occurs in the conventional method of manufacturing MCM-48. Therefore, when manufacturing MCM-48, the reaction must be stopped exactly in the middle of the reaction, thus making MCM-48 difficult to manufacture. The transition phenomenon of this structure occurs as the pH of the reaction mixture is increased due to the sodium hydroxide produced as a by-product during the hydrothermal reaction. Therefore, in the present invention, in order to overcome such disadvantages, the pH of the reaction mixture was lowered using an acid in the middle of the reaction as in step (E) of the preparation method to prevent the transition to the layered structure.

FIG. 5 shows these results: a reaction mixture having a molar composition of 5 SiO ₂ : 0.82 HTMABr: 0.18 C ₁₂ H ₂₅ O (C ₂ H ₄ O) ₄ H: 1.25 Na ₂ O: 400 H ₂ O at 100 ° C. The X-ray diffraction graph was obtained step by step while undergoing hydrothermal reaction. (a) is the reaction for 2 days at 100 ℃, (b) immediately after cooling it to room temperature to adjust the pH to 10, (c) is further reacted for 2 days at 100 ℃, (d) Is after the reaction for 30 days at 100 ℃, (e) is the case of repeating step (E) of the production method once more in (c). In Figure 5 it can be seen that the intensity of the main peak is reduced when the pH is adjusted compared to the initially formed MCM-48 structure. This is because the silicate anions in the reaction solution precipitate to amorphous silica due to the lower pH. Hydrothermal reaction at 100 ℃ again showed that the resolution and intensity of the peak were significantly improved compared to the initial X-ray diffraction graph, which means that the amorphous silicas formed as the pH was lowered were formed into the MCM-48 structure again. do. Thus, adjusting the pH does not simply stop the reaction to prevent the transition of the structure, but rather to control the equilibrium of the reaction by creating the optimal conditions under which the MCM-48 structure can be formed. The X-ray diffraction graph in (d) shows that the structure is stable even if reacted at 100 ° C. for one month. In addition, even if the pH control and hydrothermal reaction were repeated once more, MCM-48 material having excellent structural uniformity could be prepared as shown in (e). Another important fact here is that by adjusting the pH, the yield of the product can be enhanced. The yield of MCM-48 material initially obtained was only 49% based on the amount of silica used, and the yield was increased to 78% after pH adjustment and re-reaction, and to 83% when repeated once more. Compared to the conventional method, about 0.8 mole of silica is made of MCM-48 material based on 1 mole of surfactant, in the present invention, it is possible to convert more than 4 moles of silica to MCM-48 material, thereby further reducing manufacturing costs. In addition, the reaction equilibrium can be controlled thermodynamically to facilitate the preparation of the MCM-48 material as compared to conventional methods. In the present invention, similar results were obtained by combining the amounts and types of various kinds of cationic surfactants and neutral surfactants using these principles, and the results are summarized in Table 1 below. .

Mesoporous material formed according to the type and mixing ratio of the cationic surfactant and the neutral surfactant Neutral surfactant x rescue Neutral surfactant x rescue C ₁₂ H ₂₅ O (C ₂ H ₄ O) ₃ H 0.05 Hexagon (CH ₃ C (CH ₃ ) ₂ CH ₂ C (CH ₃ ) ₂ C ₆ H ₄ O (C ₂ H ₄ O) ₁₀ H 0.05 Hexagon 0.11 cube 0.11 cube 0.18 cube 0.20 cube 0.25 Stratified 0.25 Stratified C ₁₂ H ₂₅ O (C ₂ H ₄ O) ₁₀ H 0.11 Hexagon C ₁₂ H ₂₅ NH ₂ 0.11 Hexagon 0.20 cube 0.20 cube 0.25 Stratified 0.25 Stratified 5 SiO ₂ : (1-x) HTMABr: x C ₁₂ H ₂₅ O (C ₂ H ₄ O) ₄ H: 1.25 Na ₂ O: Prepared by reacting at 100 ° C. for 2 days from molar composition of 400 H ₂ O

In addition, Table 2 summarizes the results of synthesis by changing the length of the carbon chain of the cationic surfactant, it can be seen that the lattice constant, that is, the pore size of the MCM-48 material formed as the length of the chain is improved there was.

MCM-48 Manufacturing Conditions with Different Grid Constants Cationic Surfactants Neutral surfactant x Lattice constant (nm) C ₁₂ H ₂₅ N (CH ₃ ) ₃ Br C ₁₂ H ₂₅ O (C ₂ H ₄ O) ₃ H 0.25 9.28 C ₁₄ H ₂₉ N (CH ₃ ) ₃ Br C ₁₂ H ₂₅ O (C ₂ H ₄ O) ₄ H 0.20 9.77 C ₁₆ H ₃₃ N (CH ₃ ) ₃ Br C ₁₂ H ₂₅ O (C ₂ H ₄ O) ₄ H 0.18 10.24 C ₁₈ H ₃₇ N (CH ₃ ) ₃ Br (CH ₃ C (CH ₃ ) ₂ CH ₂ C (CH ₃ ) ₂ C ₆ H ₄ O (C ₂ H ₄ O) ₁₀ H 0.08 10.66 C ₂₂ H ₄₅ N (CH ₂ CH ₃ ) ₃ Br (CH ₃ C (CH ₃ ) ₂ CH ₂ C (CH ₃ ) ₂ C ₆ H ₄ O (C ₂ H ₄ O) ₁₀ H 0.08 11.31 MCM-48 material is 5 SiO ₂ : (1-x) HTMABr: x C ₁₂ H ₂₅ O (C ₂ H ₄ O) ₄ H: 1.25 Na ₂ O: 400 H ₂ O from a molar composition of 2 days at 100 ℃ Prepared by reaction.

6 shows the effect of salt on the hydrothermal stability of MCM-48 materials as in Example 3. FIG. This process uses the salt effect to enhance the hydrothermal stability of the MCM-48 material, similar to the method described in Applicant's Patent Application No. 97-6051. In the case of the MCM-48 material prepared without addition of salts, as shown in FIG. 6, after 12 hours of treatment in boiling water at 100 ° C., the silicate in the skeleton is hydrolyzed by water to completely disintegrate its structure. When salt is added to the hydrothermal reaction mixture, the structure does not change much after 12 hours in boiling water, indicating that the hydrothermal stability of MCM-48 material is greatly increased by the addition of salt. At this time, the amount of salt added was suitably 2-3 mol per mol of surfactant.

FIG. 7 is an X-ray diffraction graph obtained from samples having different amounts of aluminum, which are prepared by adding aluminum to the reaction mixture and then hydrothermally reacting the MCM-48 material to (c) of FIG. And aluminum-27 solid-state NMR spectra. The source of aluminum was sodium aluminate or aluminum chloride (AlCl ₃ ). As can be seen in FIG. 7, the structure of the MCM-48 material was maintained even when a metal was substituted in the skeleton structure. The amount of substituted aluminum was able to enhance the aluminum content with the Si / Al ratio up to 5 compared to the conventional method 15, and as shown in the aluminum-27 solid-state NMR spectrum, the tetrahedral coordination, ie, most of the aluminum skeleton It was found that it was added in. In a similar manner, metal-substituted MCM-48 materials with excellent uniformity of structure can be obtained, with up to 15 Si / Ti ratios for titanium, up to 20 Si / Sn ratios for tin, and up to 20 Si / Cu ratios for copper. Could be manufactured.

Hereinafter, the production method of the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the following examples.

Example 1

Solution A was prepared by dissolving 3.5 g of hexadecyltrimethylammonium bromide and 0.84 g of C ₁₂ H ₂₅ O (C ₂ H ₄ O) ₃ H in 40.4 g of distilled water. Solution B was prepared by mixing 31 g of 1.0 M aqueous sodium hydroxide solution with 9.4 g of Ludox HS40 (colloidal silica, manufactured by DuPont) and heating at 80 ° C. for 2 hours. The solution A was placed in a polypropylene bottle and the two solutions were mixed at room temperature for 1 hour while dropping the solution B dropwise while stirring vigorously using a magnetic stirrer. The reaction mixture was reacted at 100 ° C. for 2 days and then cooled to room temperature. The reaction mixture was neutralized to a pH of 10 using 30 wt% aqueous acetic acid and then reacted at 100 ° C. for 2 days. This cooling-neutralization-hydrothermal reaction process was carried out one more time. Thus obtained material is X-ray diffraction graph is shown in FIG. 1 and the X-ray diffraction graph obtained in each step is shown in FIG. The yield of the obtained MCM-48 material was 83% based on the amount of silica used, and the BET surface area obtained after calcining was 989 m ² / g.

Example 2

In Example 1, step (E), that is, the reaction mixture of the first hydrothermal reaction was cooled to room temperature, and then the step of adjusting the pH of the mixture again using an acid to omit the hydrothermal reaction and performing hydrothermal reaction at 100 ° C. The X-ray diffraction values of the materials prepared according to the above were measured. The reaction mixture has an initial molar composition of 5 SiO ₂ : (1-x) HTMABr: x C ₁₂ H ₂₅ O (C ₂ H ₄ O) ₄ H: 1.25 Na ₂ O: 400 H ₂ O (x is 0 to 0.25) Was prepared, and the amount of reactants is shown in Table 3 below. An X-ray diffraction graph of the samples thus obtained is shown in FIG. 4.

Amount of reactants used in Example 2 x Sodium silicate solution (g) (Na / Si = 0.5, 9% SiO ₂ ) HTMABr (g) C ₁₂ H ₂₅ O (C ₂ H ₄ O) ₄ H (g) H ₂ O (g) 0 7.12 0.78 0 9.04 0.05 7.12 0.74 0.04 9.04 0.11 7.12 0.69 0.08 9.04 0.18 7.12 0.62 0.16 9.04 0.25 7.12 0.58 0.20 9.04

Example 3

Steps (A)-(E) of the present invention were performed in the same manner as in Example 1. That is, the solution A was put in a polypropylene bottle and the two solutions were mixed at room temperature for 1 hour while dropping the solution B dropwise while stirring vigorously using a magnetic stirrer. The reaction mixture was reacted at 100 ° C. for 2 days and then cooled to room temperature. The reaction mixture was neutralized to a pH of 10 using 30 wt% aqueous acetic acid and then reacted at 100 ° C. for 2 days. After cooling the reaction, NaCl was added at 0.5, 1.0, 2.0, 4.0, and 7.0 moles per mole of total surfactant, respectively, followed by hydrothermal reaction at 100 ° C for 10 days. The remaining manufacturing method is the same as in Example 1. The obtained materials were calcined and then treated in boiling water under reflux conditions for 12 hours to determine hydrothermal stability. The results are shown in FIG.

Example 4

The manufacturing process (A)-(E) step was performed in the same manner as in Example 1. That is, the solution A was put in a polypropylene bottle and the two solutions were mixed at room temperature for 1 hour while dropping the solution B dropwise while stirring vigorously using a magnetic stirrer. The reaction mixture was reacted at 100 ° C. for 2 days and then cooled to room temperature. The reaction mixture was neutralized to have a pH of 10 using 30 wt% aqueous acetic acid, and then reacted at 100 ° C. for 2 days. After the reaction was cooled, aluminum was added in an amount of 0.025, 0.05, 0.1, and 0.2 mol per mol of the total silica using 10 wt% aqueous sodium aluminate solution, followed by hydrothermal reaction at 100 ° C. for 7 days. The remaining manufacturing method is the same as in Example 1. The X-ray diffraction graph and the aluminum-27 solid-state NMR spectrum after the calcination process for the MCM-48 material in which the aluminum thus manufactured was substituted in the skeleton are shown in FIG. 7.

As described above, the present invention generalizes the preparation of MCM-48, which was not easy by the conventional method, by developing a manufacturing method of MCM-48 in a thermodynamic equilibrium state, and by significantly increasing the yield per mole of the surfactant compared to the conventional method. The manufacturing cost was also greatly reduced. In addition, the method of the present invention is a novel synthesis method that is easy to add salt effect and metal addition during hydrothermal reaction because it is in equilibrium.

Claims (11)

In the method for producing a cubic mesoporous molecular sieve, (A) preparing an aqueous solution by mixing an alkyltrimethylammonium halide represented by Formula 1 with a neutral surfactant represented by Formula 2 or Formula 3 below; (B) preparing an aqueous sodium silicate solution; (C) mixing the aqueous sodium silicate solution of step (B) with the mixed solution of step (A); (D) first hydrothermal reaction of the reaction mixture of step (C); (E) The reaction mixture of step (D) is cooled to room temperature, and the pH of the reaction solution is lowered using an acid to prevent the transition of the layer structure and the reaction equilibrium, and then the precipitate of the final desired molecular sieve material. Secondary hydrothermal reaction to form a; (F) filtering, washing and drying the precipitate of the molecular sieve material formed in step (E); And (G) Method of producing a cubic mesoporous molecular sieve, characterized in that consisting of the step of filtration and washing in step (F), the dried precipitate is calcined. Formula 1 R ₁ R ₂ R ₃ R ₄ NX Wherein R ₁ , R ₂ and R ₃ are the same as or different from each other and are CH ₃ or CH ₂ CH ₃ , R ₄ is an alkyl group having 12 to ₂₂ carbon atoms, and X is Cl or Br. Formula 2 R (OCH ₂ CH ₂ ) nOH In the formula, R is an alkyl group having 8 to 22 carbon atoms, n is an integer of 3 to 20. Formula 3 RNH ₂ In the above formula, R is an alkyl group having 8 to 22 carbon atoms. The halogenated alkyltrimethylammonium represented by the formula (1) is a dodecyl trimethylammonium bromide, tetradecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, octadecyltrimethylammonium bromide, docosyl bromide Trimethylammonium, icosyl trimethylammonium chloride, or hexadecyltriethylammonium bromide. The method of claim 1, wherein the neutral surfactant is dodecyl polyethylene ether, hexadecyl polyethylene ether, Tritox X-100, dodecylamine, or hexadecylamine. The method of claim 1, wherein the amount of the neutral surfactant represented by Formula 2 or 3 is 0.03 to 0.95 mole based on 1 mole of alkyltrimethylammonium halide represented by Formula 1. The method of claim 1, wherein the amount of water in preparing the aqueous solution of step (A) is 100 to 1000 moles based on 1 mole of alkyltrimethylammonium halide represented by Chemical Formula 1. The method of claim 1, wherein the content of silica in the aqueous sodium silicate solution is 10 to 20% by weight. The method of claim 1, wherein the amount of the aqueous sodium silicate solution added in step (C) is 3 to 6 moles of silica based on 1 mole of alkyltrimethylammonium halide represented by Chemical Formula 1. The method of claim 1, wherein the first hydrothermal reaction temperature in the step (D) is 50 to 120 ℃, the reaction time is 1 to 6 days. The method of claim 1, wherein the acid used in step (E) is 1 to 3 M acetic acid, hydrochloric acid or sulfuric acid. The method of claim 1, wherein in step (E), the pH of the reaction mixture is 10-11, the second hydrothermal reaction temperature is 50-120 ° C, and the hydrothermal reaction time is 1-10 days. The method according to claim 1, wherein the firing conditions of step (G) are performed for 1 to 10 hours in a temperature range of 500 to 900 ° C under nitrogen and oxygen, or an air atmosphere.

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