JPH11116231A - Production of porous silica - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a porous silica large in specific surface area by removing a thermosetting resin from a composite material made of the thermosetting resin obtained by hydrolyzing and polycondensating silicon alkoxide in the specified thermosetting resin or its soln. and the silica. SOLUTION: The composite material of 1-95 wt.%, preferably 40-70 wt.% silica and the thermosetting resin is obtained by adding the silicon alkoxide expressed by the formula Si(OR)4 (R is 1-8C alkyl) to the soln. in which the thermosetting resin consisting of a phenolic resin and/or an epoxy resin is dissolved in an org. solvent and subjecting the mixture to the hydrolyzation.polycondensation in the presence of an acid catalyst. After curing the thermosetting resin by heat treating the composite material at 100-300 deg.C, the thermosetting resin is removed by heating at 400-1500 deg.C to obtain the porous silica having 300-1200 m<2> /g specific surface area and 20-100 Å average fine pore diameter. The porous silica is washed in an aq. soln. of hydrochloric acid, acetic acid, ammonia, or the like at need.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a porous silica obtained by removing a thermosetting resin from a composite of silica and a thermosetting resin, and the obtained porous silica has an excellent ratio. It has a surface area and is useful for catalysts, supports, adsorbents, fillers, and the like.

[0002]

2. Description of the Related Art Porous silica has excellent chemical and physical properties such as chemical resistance, heat resistance and strength, and is widely used as a catalyst, carrier, adsorbent, filler and the like. Conventionally, the following various methods have been known as methods for producing porous silica.

[0003] For example, after a silicon alkoxide is used as a raw material, a reaction solution is gelled by hydrolysis and polycondensation in an organic solvent, and the resulting porous gel is dried and calcined. After melt molding using an alkali metal oxide as a main raw material, heat treatment is performed at a temperature of several hundred degrees to separate phases into a phase rich in silicon dioxide, a phase rich in boron oxide and other components, There is a method of obtaining porous silica by eluting the latter with an acid.

[0004] Usually, the specific surface area of the porous silica obtained by these processes is about 10 to 200 m ² / g, as the porous silica in the development specific surface area 10 to 500 m ²
/ G has been reported (Ceramic Engineering Handbook, p. 1189). Also, a method for producing porous silica gel by a reaction with a strong acid using an aqueous solution of sodium silicate as a raw material has been reported, and its specific surface area is 200 to 700 m ² / g depending on the preparation conditions.

On the other hand, there is also known a method of preparing a porous silica by removing an organic polymer from a composite obtained from a silicon alkoxide and an organic polymer (for example, T. Sag).
usa and Y. Chujo, J .; Macromo
l. Sci. Chem. , A27, 1603, 1
996). Among them, a special polymer called poly (N-acetylethyleneimine) polyoxazoline having a triethoxyl group at a terminal is used, and after removing the organic polymer, the specific surface area of silica calcined at 600 ° C. is 800
m ² / g have been reported.

[0006]

An object of the present invention is to provide a simple method for producing porous silica having a large specific surface area, which is useful in the use of catalysts, supports, adsorbents, fillers and the like. Is to do.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, have found that the hydrolysis / polycondensation reaction of silicon alkoxide in a specific thermosetting resin or a solution thereof is carried out. After preparing a composite of thermosetting resin and silica by performing the process, it was found that the silica obtained by removing the thermosetting resin by heating or solvent extraction became silica glass with a large specific surface area. The invention has been completed.

That is, the present invention relates to (1) a thermosetting resin obtained by subjecting a silicon alkoxide to hydrolysis and polycondensation in a thermosetting resin comprising a phenol resin and / or an epoxy resin or a solution thereof. A method for producing a porous silica for removing a thermosetting resin from a composite of a resin and silica, and (2) removal of a thermosetting resin from a composite of a thermosetting resin and silica are performed in the air. 400 ℃ -1
It is performed by heating at 500 ° C. (1)
The method for producing porous silica described in,

(3) The removal of the thermosetting resin from the composite of the thermosetting resin and the silica is carried out in an inert gas atmosphere by 50%.
After carbonizing the thermosetting resin by heating at 0 ° C to 2000 ° C,
Further, the method is carried out by removing the carbide by heating to 400 ° C. to 1500 ° C. in the air, or the method for producing porous silica according to (1), or (4) a thermosetting resin and silica. The removal of the thermosetting resin from the composite with the above is carried out by washing the thermosetting resin with a solvent and removing
The method for producing porous silica according to (1), wherein the porous silica is heated to 1500 to 1500 ° C.,

(5) The weight ratio of silica / (silica + thermosetting resin) of the composite of thermosetting resin and silica is 0.
(1) characterized in that it is in the range of 1 to 0.9.
(4) The method for producing porous silica according to any one of (4) and (6) above, wherein the specific surface area of the obtained porous silica is 300 to 1200 m ² / g. It includes the method for producing porous silica according to any one of (1) to (5).

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION As a phenol resin of a thermosetting resin comprising a phenol resin and / or an epoxy resin used in the present invention, a resol type or a novolak type phenol resin or a mixture of both is used. Preferable is a phenol resin that can be dissolved in an organic solvent such as methanol, acetone, and THF.

Examples of the epoxy resin include bisphenol-type such as bisphenol-A, bisphenol-F, and tetrabromobisphenol-A; alkylphenol-type such as tertiary-butylphenol, tertiary-mylphenol, and tertiary-hexylphenol; cresol novolak-type; Phenol novolak type and the like can be mentioned, and these may be used alone or in combination of two or more.

The silicon alkoxide used in the present invention includes a silicon alkoxide monomer represented by the general formula: Si (OR) ₄ (R is an alkyl group having 1 to 8 carbon atoms) and a low-condensation obtained by partially hydrolyzing and polycondensing them. Say things.
The partial hydrolysis condensate referred to herein has an average molecular weight of 2
A commercially available product up to about 000 may be used, or a product obtained by mixing water, a solvent and, if necessary, an acid catalyst with a silicon alkoxide monomer, and stirring and holding for a predetermined time before gelation is used. May be. The content of silica in the composite obtained by adding the silicon alkoxide to the thermosetting resin solution is 1 to 95% by weight, more preferably 40 to 70% by weight.

In the present invention, it is effective to prepare a homogeneous sol solution containing a thermosetting resin and a silicon alkoxide using an organic solvent. As a preferable organic solvent, a thermosetting resin and a silicon alkoxide are dissolved homogeneously. Various organic solvents are used, for example, methanol, ethanol,
Alcohols such as 2-propanol; ethers such as tetrahydrofuran and N-methylpyrrolidone; ketones such as acetone and 2-butanone; amides such as dimethylformamide and dimethylacetamide; hexane;
Hydrocarbons such as cyclohexane, toluene,
Organic solvents such as aromatic solvents such as xylene and m-cresol, and halogen solvents such as chloroform and dichloroethane are used. The amount of the organic solvent used is not particularly limited, but usually, the total amount of the organic solvent is 10 to 10 of the entire sol solution.
It is used in the range of 90% by weight.

The method for producing porous silica in the present invention includes the following method. First, a thermosetting resin is dissolved in an organic solvent, and if necessary, a predetermined amount of a silicon alkoxide solution containing water and / or a catalyst is added to prepare a homogeneous mixed sol solution. The homogeneous sol solution as it is,
Alternatively, after performing operations such as application and injection, ventilation, decompression,
Alternatively, the hydrolysis / polycondensation reaction of silicon alkoxides and the removal of the solvent are advanced by heating to obtain a composite of a thermosetting resin and silica.

The composite of the thermosetting resin and silica obtained in the present invention is preferably a homogeneous composite in which the thermosetting resin and silica are finely dispersed in each other. By removing the thermosetting resin from the composite of the thermosetting resin and silica by any of the following methods, porous silica having a specific surface area of 300 to 1200 m ² / g can be obtained. The average pore diameter is usually 20 to 100 Å.

As a method for removing the thermosetting resin, 100
After hardening the thermosetting resin in the composite by performing a heat treatment at ~ 300 ° C, this is cured in air at 400 ~ 1500.
Or a method of removing the thermosetting resin by heating at a temperature of 100 to 300 ° C. Alternatively, a composite of the thermosetting resin and the silica obtained by performing a heat treatment at a temperature of 100 to 300 ° C is heated to 500 to 2000 in an inert gas atmosphere. There is a method of heating at 400C to carbonize the thermosetting resin, followed by heating at 400 to 1500C in air to remove the carbide.

Furthermore, after removing the thermosetting resin from the uncured composite of the thermosetting resin and silica using an organic solvent for dissolving the thermosetting resin, for example, methanol, etc., the porous material is removed by solvent removal and heat treatment. There is a method for obtaining high quality silica gel. When removing the thermosetting resin with an organic solvent, acetic acid, ammonia or the like and / or water may be allowed to coexist in the organic solvent as necessary. Further, by heating the obtained porous silica gel at 100 to 1500 ° C., a porous silica glass having a large specific surface area can be obtained.

The porous silica obtained by the production method of the present invention can be made into porous silica having different average pore diameters by changing the raw materials, composition, preparation conditions of the composite, removal conditions of the thermosetting resin, and the like. Besides, the pore diameter can be controlled by washing the porous silica in an aqueous solution of hydrochloric acid, acetic acid, ammonia or the like.

[0020]

The present invention will be described in more detail with reference to the following examples and comparative examples, but the present invention is not limited to the following examples.

Example 1 Phenol resin (Plyofen J-325, manufactured by Dainippon Ink and Chemicals, Inc.)
Resol type, methanol solvent, solid content = 60%) 100
A homogenous mixture consisting of 50 parts by weight of methanol, 180 parts by weight of tetramethoxysilane (hereinafter abbreviated as TMOS: special grade reagent manufactured by Tokyo Chemical Industry Co., Ltd.) and 85 parts by weight of water with respect to parts by weight (60 parts by weight as resin content). The solution was dropped and mixed with stirring to prepare a homogeneous mixed solution. Thereafter, the mixture was cast into a clean polystyrene container, and then the solvent was slowly cast at 25 ° C. for about 1 day, and then cast in a hot air drier at 80 ° C. for 10 hours.
The mixture was kept at 50 ° C. for 1 hour to obtain a composite of a phenol resin and silica. The content of silica in the composite was 51% by weight.

The resulting composite of phenolic resin and silica was heated in air at 600 ° C. for 3 hours to remove the phenolic resin and obtain a porous silica glass. The specific surface area and the average pore diameter were measured using a fully automatic gas adsorption amount measuring apparatus, Autosorb-1-C, manufactured by Yuasa Ionics Co., Ltd. The specific surface area was 863 m ² / g, and the average pore diameter was 31 Å.

Example 2 10 g of a 10% aqueous ammonia solution was added to 1 g of the porous silica glass obtained in Example 1, washed in the same solution for 18 hours, then in water for 1 day, and dried at 120 ° C. did. The specific surface area of the obtained porous silica glass was 386 m ² / g, and the average pore diameter was 65 Å.

Example 3 The composite of phenolic resin and silica obtained in Example 1 was heated in air at 800 ° C. for 3 hours to obtain a porous silica glass. Its specific surface area is 55
It was 8 m ² / g.

Example 4 The composite of phenolic resin and silica obtained in Example 1 was heated at 1050 ° C. for 1 hour in an infrared image furnace under a nitrogen stream to carbonize the phenolic resin. The composite of the carbonized phenolic resin and silica was heated in air at 600 ° C. for 15 hours to remove carbides and obtain porous silica glass. The specific surface area of the obtained porous silica glass was 585 m ² / g.

The specific surface area of the porous silica glass obtained by removing the carbide by heating the composite of the carbonized phenolic resin and silica at 1000 ° C. for 3 hours in the air was 313 m ² / g. . This means that a complex of phenolic resin and silica is directly passed through air without passing through carbide.
The specific surface area of the porous silica glass obtained by removing the phenolic resin by heating at 3 ° C. for 3 hours is 129 m ² / g.
It was bigger.

(Examples 5 and 6) Example 1 was repeated except that the content of silica in the composite of phenolic resin and silica was 1% by weight in Example 5 and 75% by weight in Example 6.
A porous silica glass was obtained in the same manner as described above. The specific surface area of the obtained porous silica glass was 529 in Example 5.
m ² / g, and in Example 6, it was 681 m ² / g.

(Example 7) Phenol resin (Plyofen J-325, manufactured by Dainippon Ink and Chemicals, Inc.)
Resol type, methanol solvent, solid content = 60%) 100
A homogeneous solution consisting of 50 parts by weight of methanol, 180 parts by weight of tetramethoxysilane (special grade reagent manufactured by Tokyo Kasei Kogyo Co., Ltd.) and 85 parts by weight of water is mixed dropwise with stirring with respect to parts by weight (60 parts by weight as a resin component). , To prepare a homogeneous mixed solution. Thereafter, the mixture was kept at 25 ° C. to gel the homogeneous solution to obtain a composite of phenol resin and silica. The content of silica in the composite was 55% by weight. The phenolic resin in the complex was removed by washing in a large amount of methanol solution.
Heated at 50 ° C. The specific surface area of the obtained porous silica glass was 1000 m ² / g, and the average pore diameter was 27 Å.

Example 8 A large amount of methanol / water / ammonia (weight ratio = 20/3/1) was prepared by mixing the phenol resin in the composite of phenol resin and silica obtained in Example 7 with a large amount.
It was washed and removed in the mixed solution and heated at 150 ° C. The specific surface area of the obtained porous silica glass is 624 m ² /
g, the average pore size was 66 Å.

(Examples 9 to 11) 100 parts by weight of an epoxy resin (bisphenol type epoxy resin (manufactured by Dainippon Ink and Chemicals, Inc., Epicron 850)) and an aliphatic amine curing agent (manufactured by Dainippon Ink and Chemicals, Inc.) B05
3) and 20 parts by weight were previously added in 50 parts by weight of THF.
After reacting for hours, in Example 9, THF 80 parts by weight, methanol 20 parts by weight, TMOS 210 parts by weight, water 100 parts by weight.
A homogeneous solution consisting of parts by weight was mixed with THF 80 in Example 10.
Parts by weight, 20 parts by weight of methanol, low condensate of TMOS (MS51, molecular weight 500, manufactured by Mitsubishi Chemical Corporation) 16
Example 1 A homogeneous solution consisting of 0 parts by weight and 23 parts by weight of water was prepared in Example 1.
In No. 1, 500 parts by weight of THF, 140 parts by weight of methanol,
Low condensate of TEOS (ES40 manufactured by Colcoat Co., Ltd.)
A homogenous solution consisting of 900 parts by weight (molecular weight: 745) and 85 parts by weight of water was dropped and mixed to prepare a homogeneous mixed solution.

Thereafter, the mixture was kept at 25 ° C. to gel the homogeneous solution to obtain a composite of an epoxy resin and silica gel. The content of silica in the composite was 39% by weight in Example 9, 36% by weight in Example 10, and 62% by weight in Example 11. The specific surface area and the average pore diameter of the porous silica glass obtained by removing the epoxy resin by heating the composite of the obtained epoxy resin and silica in air at 600 ° C. for 3 hours are as follows. 964 m ² / g, 41 Å, Example 10 at 956 m ² / g, 45 Å, Example 11 at 772 m ² / g, 42
Angstrom.

Comparative Example 1 100 parts by weight of methanol, T
A homogeneous solution consisting of 100 parts by weight of MOS and 43 parts by weight of water was prepared, and then cast into an aluminum cup.
The solvent was slowly cast for about 1 day, then in an 80 ° C. hot air drier for 10 hours, kept at 150 ° C. for 1 hour, and finally heated in air at 600 ° C. for 3 hours. The specific surface area of the obtained porous silica glass is 147 m.
² / g.

[0033]

The present invention can provide a simple method for producing porous silica having a large specific surface area, which is useful in the use of catalysts, supports, adsorbents, fillers and the like.

Claims (6)

[Claims] 1. A composite of a thermosetting resin and silica obtained by subjecting a silicon alkoxide to hydrolysis and polycondensation in a thermosetting resin comprising a phenol resin and / or an epoxy resin or a solution thereof. For producing a porous silica, wherein a thermosetting resin is removed from the product. 2. The method according to claim 1, wherein the removal of the thermosetting resin from the composite of the thermosetting resin and silica is performed at 400 ° C. to 1500 ° C. in air.
The method for producing porous silica according to claim 1, wherein the method is performed by heating at a temperature of ° C. 3. Removal of the thermosetting resin from the composite of the thermosetting resin and silica is performed at 500 ° C. in an inert gas atmosphere.
The porous silica according to claim 1, wherein the carbonization is performed by heating the thermosetting resin to a temperature of from 2000 to 2000C, and then removing the carbide by heating to 400C to 1500C in the air. Manufacturing method. 4. The method of removing a thermosetting resin from a composite of a thermosetting resin and silica, wherein the thermosetting resin is washed and removed with a solvent, and further heated to 100 ° C. to 1500 ° C. The method for producing porous silica according to claim 1. 5. A weight ratio of silica / (silica + thermosetting resin) of the composite of thermosetting resin and silica of 0.1 to 0.1.
The method for producing porous silica according to any one of claims 1 to 4, wherein the range is 0.9. 6. The obtained porous silica has a specific surface area of 3
Method for producing a porous silica according to any one of claims 1 to 5, characterized in that 00~1200m is ² / g.