JP3498135B2 - Crystalline porous silica compound-strongly acidic cation exchange resin composite and preparation method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a composite of a crystalline porous silica compound and a strongly acidic cation exchange resin, a method for preparing the same, and a catalyst comprising the composite.

[0002]

2. Description of the Related Art Nafion (registered trademark, manufactured by DuPont), which is a strongly acidic cation exchange resin, is widely applied not only as an ion exchange resin or an ion exchange membrane, but also as a solid strong acid catalyst or the like. Nafion as a solid acid catalyst
(A commercially available NR-50 (registered trademark, manufactured by DuPont) is a typical example), which exhibits an excellent catalytic action in a reaction using an oxygen-containing compound such as alcohol or carboxylic acid. this is,
Since alcohol etc. swell the catalyst and the pores of the catalyst expand,
This is because the strongly acidic sulfonic acid group having a catalytic action can easily come into contact with the substrate.

However, in a reaction system in which the reaction substrate is a hydrocarbon, the reaction becomes extremely slow. This is because hydrocarbons cause little swelling of the catalyst and the pores of the catalyst remain small so that the diffusion of the reaction substrate into the catalyst is slow. The conversion reaction of hydrocarbons with a strongly acidic catalyst is industrially important, and it is necessary to overcome this drawback in order to improve the versatility of the Nafion catalyst.

Recently, the DuPont research group has investigated the composite of amorphous silica, which is an inorganic porous solid, and Nafion (S
AC-13 (registered trademark, manufactured by DuPont) was prepared, and when this complex was used for the reaction of hydrocarbons, it was reported that the substrate diffused rapidly in the catalyst and the reaction proceeded at a good rate ( M.
A. Harmer et al. Am. Chem. Soc., Vol.118, p. 7708, 1
996).

However, in the above composite, since silica is amorphous and the size of the pores varies, it is possible to simply promote the contact between the sulfonic acid group in the solid Nafion and the substrate. However, the catalytic properties of the sulfonic acid group have not been improved.

On the other hand, in recent years, research on crystalline porous silica having mesopores (mesoporous silica) has been actively conducted. As such crystalline porous silica, for example, MC
M-41 (JS Beck et al., J. Am. Chem. Soc., Vol. 114, 10)
834, 1992). This mesoporous silica is
It is a one-dimensional array of pores of a certain diameter, and its unique reaction field is expected to bring about new reactivity and selectivity.

With respect to the mesopore compound as well, it is desired to form a composite with an organic substance for the purpose of improving the catalytic properties.
So far, attempts have been made to introduce a simple organic group such as a methyl group on the surface of pores to lower the hydrophilicity of the solid surface and improve the hydrophobicity (for example, N. Igarashi et al., Chem. Let.
t., p. 1, 1999). However, since a high temperature of 130 ° C. or higher is usually required in the crystallization process for forming mesopores, it is difficult to introduce a complicated organic compound. In fact, such a compound has not been reported yet, and a composite of a crystalline porous silica compound and an organic polymer has not been known at all.

[0008]

The main object of the present invention is to provide a complex of a novel crystalline porous silica compound and an organic polymer, a method for preparing the same, and a catalyst comprising this complex. .

[0009]

As a result of intensive studies, the inventor has found that a complex of a crystalline porous silica compound and a strongly acidic cation exchange resin can be prepared, and completed the present invention. It was

That is, the present invention provides the following complex, its preparation method and its use. 1. A composite of a crystalline porous silica compound and a strongly acidic cation exchange resin. 2. 2. The composite according to 1 above, wherein the crystalline porous silica compound is mesoporous silica. 3. The complex according to the above 1, wherein the strongly acidic cation exchange resin is a strongly acidic cation exchange resin having a sulfonic acid group. 4. A method for preparing a complex of a crystalline porous silica compound and a strong acid cation exchange resin, which comprises heating a mixture of a silicon alkoxide, a cationic surfactant, a strong acid cation exchange resin and a solvent. 5. The cationic surfactant is a quaternary ammonium salt,
5. The method for preparing a complex as described in 4 above, which is at least one selected from the group consisting of an alkylamine salt and a quaternary ammonium hydroxide salt. 6. A catalyst for the dimerization reaction of styrene or a styrene derivative, which comprises a complex of a crystalline porous silica compound and a strongly acidic cation exchange resin.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The composite of the present invention is a composite of a crystalline porous silica compound and a strongly acidic cation exchange resin.

The crystalline porous silica compound portion in the composite of the present invention is not particularly limited as long as it is a porous silica compound having a regular pore structure, and is substantially uniform constituted by one-dimensional pores. It preferably has a regular pore structure. The one-dimensional pore structure refers to a state in which tubular capillaries are aligned in the same direction and further stacked. Examples of such a compound include a mesoporous silica compound. Examples of such mesoporous silica compounds include MCM-41, MCM-48, MCM-
50, FSM-16, etc. Alternatively, for example, a mesoporous silica compound containing an oxide such as zirconium or titanium may be used.

The size of the pores (of the crystalline porous silica compound portion) in the composite of the present invention is not particularly limited as long as it is a mesopore. Most of the pores in the composite of the present invention
The diameter of (hereinafter referred to as "main pores") is not particularly limited as long as it is a mesopore, but is usually about 1 to 10 nm, preferably 1
It is about 5 nm, particularly preferably about 2-4 nm. The ratio of the main pores in the composite to the entire pores is not particularly limited, but is usually about 70% or more, preferably about 85 to 100%. A composite having a mesoporous silica compound portion in which the ratio of the main pores to all the pores is about 85% or more and the diameter of the main pores is about 2 to 4 nm is particularly preferable. The value of the pores of the composite and the ratio of the main pores to the entire pores are calculated from the adsorption isotherm of the nitrogen adsorption method by BJH (Barnett-Joyn
er-Halenda) method.

The specific surface area of the composite is not particularly limited, but is usually 200 to 1000 as the BET specific surface area by nitrogen adsorption.
m ² / g approximately, and preferably from 400 to 800 m ² / g approximately. The pore volume of the composite is not particularly limited, but is usually about 0.1 to 1 cm ³ / g, preferably about 0.4 to 0.8 cm ³ / g. The values of BET specific surface area and pore volume in the present invention are values calculated by the adsorption isotherm of nitrogen adsorption.

The strong acid cation exchange resin portion in the composite of the present invention is not particularly limited, but it is preferable that the ion exchange resin portion exhibits an acidity of about pKa ≦ 3. further,
Particularly preferred is a complex in which the strongly acidic cation exchange resin moiety does not decompose below about 130 ° C. Examples of the strongly acidic cation exchange resin moiety in the complex of the present invention include ion exchange resins having functional groups such as sulfonic acid groups. As the ion exchange resin having a sulfonic acid group, a perfluorocarbon sulfonic acid resin
(For example, Nafion (registered trademark, manufactured by DuPont) and the like) can be exemplified.

The shape of the composite is not particularly limited and may be a desired shape such as a granular shape or a film shape depending on the application. Alternatively, it is possible to add a known binder as required and mold.

The composite of the present invention can be prepared, for example, by heating a mixture of a silicon alkoxide, a cationic surfactant, a strongly acidic cation exchange resin and a solvent.

The order of mixing is not particularly limited. For example, (i) an alcoholic solution of a strongly acidic cation exchange resin and (ii) an aqueous solution containing a cationic surfactant are separately prepared, and after mixing these, , Silicon alkoxide may be mixed. Next, the obtained mixture is heated to obtain a composite. Precipitation occurs when the raw materials are mixed, but the solution and the precipitate are all heated.

The silicon alkoxide used is not particularly limited as long as it is a silicon compound having at least one C1 to C3 alkoxy group. For example, tetramethoxysilane and tetraethoxysilane can be exemplified.

The strong acid cation exchange resin to be used is not particularly limited and may be appropriately selected so that the strong acid cation exchange resin portion of the resulting complex is desired. pKa ≦ 3
Strongly acidic cation exchange resins that exhibit a degree of acidity are preferred. For example, a strongly acidic cation exchange resin having a sulfonic acid group or the like as a functional group can be exemplified. As a strongly acidic cation exchange resin having a sulfonic acid group, a perfluorocarbon sulfonic acid resin (for example, Nafion
(Registered trademark, manufactured by DuPont) and the like can be exemplified.

The strong acid cation exchange resin is preferably dissolved in a solvent such as alcohol. Alternatively, it may be used after it is once dissolved and then gelled by distilling off the solvent.

The amount of the strongly acidic cation exchange resin can be appropriately set depending on the type and the like, but is usually about 20% or less, preferably about 5 to 10% by weight with respect to silica.

The cationic surfactant used is not particularly limited, but those capable of forming micelles in an aqueous solution are preferable. For example, a quaternary ammonium salt, an alkylamine salt, a quaternary ammonium hydroxide salt, etc. can be illustrated.

As the quaternary ammonium salt, for example,
R ₁ R ₂ R ₃ R ₄ NX [wherein, R _{1 to} R ₄ are the same or different and each represents a linear alkyl group, and X represents a halogen atom such as F, Cl, Br, or I]. It can be illustrated. The carbon number of the linear alkyl group represented by R _{1 to} R ₄ is usually about 1 to 25,
It is preferably about 1 to 20. Among these, R _{2 to} R ₄
Is preferably a quaternary ammonium salt in which at least one is a methyl group, and particularly preferably a quaternary trimethylammonium salt in which R _{2 to} R ₄ are methyl groups. Specific examples of the quaternary alkyl trimethyl ammonium salt include octyl trimethyl ammonium chloride, octyl trimethyl ammonium bromide, decyl trimethyl ammonium chloride, decyl trimethyl ammonium bromide,
Dodecyl trimethyl ammonium chloride, dodecyl trimethyl ammonium bromide, hexadecyl trimethyl ammonium chloride, hexadecyl trimethyl ammonium bromide, octadecyl trimethyl ammonium chloride, octadecyl trimethyl ammonium bromide, etc. are mentioned.

As the alkylamine salt, R ₁ R ₂ R ₃ NHX [in the formula, R _{1 to} R ₃ are the same or different and each represents a linear alkyl group, and X is F, Cl, Br or I. And the like, which represents a halogen atom, etc. The linear alkyl group represented by R _{1 to} R ₃ preferably has 8 to 25 carbon atoms, particularly 8 to 17 carbon atoms.
Is preferred. Specific examples of the alkylamine salt include trioctyl ammonium chloride, trioctyl ammonium bromide, tridecyl ammonium chloride,
Examples thereof include tridecyl ammonium bromide, tridodecyl ammonium chloride, tridodecyl ammonium bromide, trihexadecyl ammonium chloride, trihexadecyl ammonium bromide, trioctadecyl ammonium chloride and trioctadecyl ammonium bromide.

As the quaternary ammonium hydroxide salt, for example, R ₁ R ₂ R ₃ R ₄ NOH [wherein R _{1 to} R ₄ are the same or different,
Which represents a linear or molecular C ₁ -C ₃ alkyl] can be exemplified. Among these, a quaternary ammonium hydroxide salt in which at least one of R _{2 to} R ₄ is a methyl group is preferable, and a quaternary tetramethylammonium salt in which R _{1 to} R ₄ is a methyl group is particularly preferable. Specific examples of the quaternary ammonium hydroxide salt include tetramethylammonium hydroxide,
Examples thereof include trimethylethylammonium hydroxide, trimethylpropylammonium hydroxide, dimethyldiethylammonium hydroxide and the like.

These cationic surfactants may be used either individually or in combination of two or more. Two
When using in combination of two or more species, a combination of (i) at least one species selected from the group consisting of quaternary ammonium salts and alkylamine salts and (ii) at least one quaternary ammonium hydroxide salt is preferred. .

The amount of the cationic surfactant can be appropriately set depending on the kind of the surfactant used and the like.
The molar ratio to silicon alkoxide is usually about 5 to 50%, preferably about 10 to 30%. Alternatively, when it is made into a solution, it may have a critical micelle concentration or higher.

The solvent used is not particularly limited, but examples thereof include alcohols such as methanol, ethanol and propanol; water; mixed solutions of these.

The temperature for heating the mixture of the silicon alkoxide, the cationic surfactant, the strongly acidic cation exchange resin and the solvent is not particularly limited, but is usually about 110 to 150 ° C, preferably about 120 to 140 ° C. The heating time is not particularly limited, but is usually about 0.5 to 5 days, preferably 1 to 2
It is about a day. The reaction pressure is usually about 0.2 to 1 MPa, preferably about 0.4 to 0.6 MPa. The atmosphere for heating is not particularly limited, and may be an oxidizing atmosphere such as air or an inert gas atmosphere such as nitrogen or halogen.

After heating, the composite may be recovered by a known method such as filtration and dried if necessary. Further, if necessary, the obtained complex is H ₂ SO ₄ , a solution containing an acid such as HCl (solvent: alcohol such as methanol or ethanol,
It may be dispersed in water, a mixed solvent thereof, or the like) and stirred. At this time, heating / refluxing may be carried out, if necessary, and this operation may be repeated several times. Further, if necessary, the composite may be heated again at about 120 to 170 ° C. for about 10 to 20 hours.

The composite of the present invention can be suitably used as a solid acid catalyst or the like. INDUSTRIAL APPLICABILITY The complex of the present invention can be suitably used as a catalyst for a dimerization reaction of styrene, a styrene derivative or the like, particularly as a catalyst for a dimerization reaction of styrene or a styrene derivative without cyclization.

As the styrene derivative which is a reaction raw material,
Examples thereof include styrene having a vinyl group moiety and / or a benzene ring moiety substituted.

Examples of the substituent of the vinyl group portion of the styrene derivative include linear / branched alkyl groups having about C1 to C5. Specific examples include a methyl group, an ethyl group, an isopropyl group, a t-butyl group, and an n-pentyl group. Examples of the styrene derivative in which the vinyl group moiety is substituted include α-methylstyrene and β-methylstyrene.

Examples of the substituent at the benzene ring portion of the styrene derivative include a C1-C4 linear / branched alkyl group and the like. Specifically, a methyl group, an ethyl group, an isopropyl group, a t-butyl group and the like can be exemplified. The substitution site on the benzene ring is not particularly limited,
Any of o-position, p-position and m-position may be used. The number of substituents in the styrene derivative is usually about 1 to 3 and preferably 1. Examples of the styrene derivative in which the benzene ring moiety is substituted include o-methylstyrene, p-methylstyrene, p-ethylstyrene, p-isopropylstyrene, pt-butylstyrene and the like.

The amount of the composite of the present invention to be used is not particularly limited as long as a predetermined effect can be obtained, but it is usually 1 to 20% by weight with respect to styrene or a styrene derivative as a raw material.
It is about 5 to 10%, preferably about 5 to 10%.

The reaction time is usually about 2 to 10 hours, preferably about 4 to 6 hours. Reaction temperature is usually 30-100 ℃
It is about 50 to 70 ° C. When carrying out the dimerization reaction, styrene as a raw material, a styrene derivative or the like may be dissolved in a solvent such as toluene, hexane, dichloromethane or chloroform, if necessary.

When the catalyst of the present invention is used, a pretreatment for increasing the activity can be carried out before use.
For example, heat treatment can be performed under vacuum before using the composite. Alternatively, the strongly acidic cation exchange resin portion of the complex may be in the H ⁺ type by using a known method such as ion exchange. Even when such pretreatment is not performed, the catalyst of the present invention can exhibit a certain catalytic activity.

After being used once, the catalyst of the present invention can be regenerated by a method such as stirring in a strongly acidic solution, if necessary.

[0040]

According to the present invention, a composite of an inorganic solid having regular pores and an organic polymer can be obtained.

By using the catalyst of the present invention, the dimerization reaction of styrene and a styrene derivative can be carried out with high selectivity. According to the catalyst of the present invention, in the dimerization reaction of α-methylstyrene, 2,4-diphenyl-4-methyl-
1-Penten can be obtained.

[0042]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Example 1: Preparation of MCM-41 type crystalline porous silica compound-Nafion complex 2 ml of a 5% propanol solution of Nafion was distilled under reduced pressure,
The solvent was distilled off sufficiently to obtain a gel. To the obtained gel-like material (about 0.1 g), 1.5 ml of ethanol was added, and sufficiently stirred to dissolve. This solution prepared by dissolving tetramethylammonium hydroxide (1.44g) and hexadecyltrimethylammonium bromide (1.64g) in 15ml of distilled water (the former is easily soluble in water, the latter is insoluble in water and is a surfactant). Therefore, micelles were formed.) And well stirred at room temperature. Then
Add tetraethoxysilane to this solution with vigorous stirring.
(6.44g) was added slowly. A white precipitate formed at this stage. Then, all of the precipitate and the solution were transferred to a Teflon beaker, and the beaker was placed in a stainless autoclave. The autoclave was closed and heated at 130 ° C. for 24 hours in an air atmosphere. The pressure was automatically raised by heating. After the reaction was completed, the white precipitate formed in the beaker was filtered off, washed with a large amount of distilled water, and then dried in air at 60 ° C for 12 hours.
Dried for hours. Next, this precipitate was added to a mixed solution of 300 ml of ethanol and 3 ml of concentrated sulfuric acid, and the mixture was refluxed for 18 hours. After refluxing, the precipitate was filtered off, washed well with a large amount of ethanol, and dried in air at 150 ° C. for 14 hours to obtain a crystalline porous silica compound-strong acidic cation exchange resin complex.

When the crystallinity of the produced solid was analyzed by powder X-ray diffraction, the same diffraction pattern as that of MCM-41 which is a crystalline porous silica compound having mesopores was obtained. The BET specific surface area was 609 m ² / g based on the nitrogen adsorption data. The diameter of the main pores of the obtained composite was 2.9 nm, the ratio of the main pores to the entire pores was about 88%, and the pore volume was 0.641 cm ^3.
/ g, which was almost the same as that of MCM-41. In the infrared absorption spectrum, in addition to the absorption attributed to MCM-41, the absorptions of 1150 and 1250 cm ^-1 attributed to Nafion were also observed,
All results supported complex formation.

Example 2 5 ml of a 5% solution of Nafion in propanol was distilled under reduced pressure,
The solvent was distilled off sufficiently to obtain a gel. To the obtained gel-like material (about 0.25 g), 1.5 ml of ethanol was added, and sufficiently stirred to dissolve. Using this solution, a crystalline porous silica compound-strongly acidic cation exchange resin composite was obtained in the same manner as in Example 1.

The powder X-ray diffraction of the obtained composite was found to be MCM-41.
Was similar to. From the nitrogen adsorption data, the BET specific surface area was 569 m ² / g, the diameter of the main pores was 2.9 nm, the ratio of the main pores to the entire pores was about 85%, and the pore volume was 0.621 cm ³ / g. It was

Example 3: Synthesis of 2,4-diphenyl-4-methyl-1-pentene by dimerization reaction of α-methylstyrene 0.591 g (5 mmol) of α-methylstyrene was dissolved in 5 ml of toluene. MCM-41 prepared in this solution in the same manner as in Example 1
Type crystalline porous silica compound-Nafion complex (50 mg) was added, and the reaction was carried out at 60 ° C under an argon atmosphere with vigorous stirring. The reaction solution was collected at any time, and the product was analyzed by gas chromatography.

As a comparison, instead of the MCM-41 type crystalline porous silica compound-Nafion complex, a strongly acidic cation exchange resin, Nafion NR-50, Amberlyst-15 or an amorphous silica-Nafion complex. The same reaction was carried out using SAC-13 (which is a commercial product) as a catalyst. The results are shown in Fig. 1. MCM-41 instead of uncatalyzed or MCM-41 type crystalline porous silica compound-Nafion composite
When was used as a catalyst, the reaction did not proceed at all.

As is apparent from FIG. 1, the MCM-41 of the present invention.
When the type crystalline porous silica compound-Nafion composite was used, 2,4-diphenyl-4-methyl-1-pentene was produced highly selectively. In addition, when this composite was used, a high yield was obtained in a short time as compared with other catalysts.

Example 4: 1,3 by dimerization reaction of styrene
-Synthesis of diphenylbutane To a solution prepared by dissolving 0.52 g (5 mmol) of styrene in 10 ml of toluene was added 50 mg of MCM-41 type crystalline porous silica compound-Nafion complex prepared in the same manner as in Example 1, and the mixture was placed under an argon atmosphere. The reaction was carried out at 70 ° C for 24 hours with vigorous stirring. The reaction solution was collected and the product was analyzed by gas chromatography. Styrene dimer 1,3-diphenylbutane was obtained with a yield of 10%.

When an amorphous silica-Nafion composite SAC-13 (commercially available product) was used as a catalyst instead of the MCM-41 type crystalline porous silica compound-Nafion composite, 1,3 -The yield of diphenylbutane was 6%. When MCM-41 was used as a catalyst instead of the non-catalyst or MCM-41 type crystalline porous silica compound-Nafion composite, the reaction did not proceed at all.

[Brief description of drawings]

FIG. 1 shows the time-dependent changes in the yield (%) of 2,4-diphenyl-4-methyl-1-pentene in the dimerization reaction of α-methylstyrene described in Example 3.

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Claims (7)

(57) [Claims] 1. An alcohol of (i) a strongly acidic cation exchange resin.
Solution and (ii) an aqueous solution containing a cationic surfactant.
Prepared separately and after mixing them, silicon alkoxy
And mixing the mixture and heating the resulting mixture.
Crystalline mesoporous silica and strongly acidic cation exchange resin
A method for preparing a complex with. 2. The strongly acidic cation exchange resin is sulfonic acid.
The strong acid cation exchange resin having a group, according to claim 1.
Preparation method of loading. 3. A cation type surfactant is a quaternary ammone.
Aluminum salts, alkylamine salts and quaternary ammonium hydroxide
At least one selected from the group consisting of um salts
The preparation method according to claim 2, wherein 4. The preparation method according to claim 1.
Crystalline mesoporous silica and strong acidity
Complex with cation exchange resin. 5. A styre formed from the composite according to claim 4.
Of benzene or styrene derivative. 6. (i) Alcoh, a strongly acidic cation exchange resin
Solution and (ii) an aqueous solution containing a cationic surfactant.
Prepared separately and after mixing them, silicon alkoxy
A catalyst obtained by mixing the catalyst and heating the resulting mixture. 7. Dimerization of styrene or a styrene derivative
The catalyst according to claim 6, which is a reaction catalyst.