JP2003221219A - Silica gel carrying heteroelement - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a silica gel having not only a large pore volume and a large specific surface area but also a narrow pore size distribution as well as excellent heat resistance and waterproofness, capable of carrying a desired amount of useful elements and suppressing amounts of useless metal impurities. <P>SOLUTION: This silica gel is characterized in that (a) the pore volume is 0.3 to 1.6 ml/g, (b) the specific surface area is 200 to 900 m<SP>2</SP>/g, (c) the most frequent diameter (D<SB>max</SB>) of pores is <20 nm, (d) the total volume of pores having diameter in the range of D<SB>max</SB>±20% is ≥40% of the total volume of all pores, (e) the total content of elements belonging to the group comprising alkali metals and alkaline earth metals is ≤300 ppm, (f) the content of useful heteroelements belonging to the group comprising groups XIII, XIV and XV in the periodic table and transition metals is ≥0.1%, (g) simple substances and/or compounds of the useful heteroelements are carried or held on the surface of the silica gel in the form of particulates and (h) the diameter of the particulates is ≤D<SB>max</SB>×2.5. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel foreign element-supporting silica gel having excellent heat resistance and water resistance.

[0002]

2. Description of the Related Art Silica gel has been widely used as a desiccant for a long time, but recently its use has expanded to catalyst carriers, separating agents, adsorbents, and the like. Performance requirements are also diversifying. The performance of silica gel is determined by the physical properties such as surface area, pore size, pore volume, and pore size distribution of silica gel, and these physical properties are greatly affected by the silica gel production conditions.

As a method for producing silica gel, the most commonly used method is to hydrolyze an alkali silicate salt such as sodium silicate with a mineral acid and gelate the resulting silica hydrosol to dry it. In order to improve the performance of silica gel, many proposals have been made regarding the details of this manufacturing method.

For example, in Patent Document 1, silica hydrosol produced by the reaction of an aqueous alkali silicate solution and a mineral acid is gelated and treated with an acid solution having a pH of 2.5 or less,
After washing with water, a method has been proposed for producing silica gel having a narrow pore distribution by adjusting the pH to 4-9 in an aqueous solution having a buffer action and performing hydrothermal treatment. In addition, Patent Document 2
Proposes a method in which the silica hydrogel is dried by batch fluidized drying, followed by hydrothermal treatment.

According to these production methods, the performance of the obtained silica gel is certainly changed, and silica gel having a sharper pore distribution can be produced. But,
The pore volume, specific surface area and average pore diameter of the obtained silica gel cannot be sufficiently changed, and the heat resistance and water resistance are not sufficient, so that it is not sufficient as a method for obtaining silica gel in a desired physical property range. is there.

Further, silica gel obtained by the former method using an alkali silicate salt as a raw material usually contains a considerable amount of impurities such as sodium, calcium and magnesium derived from the raw material. The presence of impurities in silica gel
Even if the total content is a trace amount of several hundred ppm, it has a great influence on the performance of silica gel. For example, 1) the presence of these impurities promotes the crystallization of silica gel at high temperature, 2) the presence of these impurities promotes the hydrothermal reaction of silica gel in the presence of water, and This leads to volume expansion, specific surface area reduction, and pore size distribution expansion. 3) Since these impurities reduce the sintering temperature, heating silica gel containing these impurities promotes the reduction of the specific surface area. And the like. This effect is particularly strong in impurities containing an element belonging to an alkali metal or an alkaline earth metal.

On the other hand, as a method for producing high-purity silica gel containing very few impurities, there are known a method of purifying a gel obtained by neutralizing an alkali silicate salt and a method of hydrolyzing a silicon alkoxide. In particular, in the latter method, since the silicon alkoxide can be purified by distillation or the like, it is possible to obtain silica gel of high purity relatively easily. However, silica gel obtained from a silicon alkoxide by the sol-gel method generally has a small average pore diameter and a wide pore distribution. Moreover, even if hydrothermal treatment is applied to this silica gel, there is almost no report of noticeable improvement in performance.

On the other hand, Non-Patent Document 1 discloses that an electrically neutral
After forming a supramolecular structure consisting of hydrogen bonds between the gemini surfactant and the silica precursor, the gemini surfactant is removed to obtain heat resistance (1000 ° C) and water resistance (1
It is described that a mesoporous molecular sieve having a temperature of 00 ° C. for 150 hours or more) is produced. This is a kind of so-called micellar template silica that forms pores using an organic template, and it is possible to produce silica gel having a very sharp pore distribution compared to the above-mentioned respective conventional techniques. it can. However,
In this production method, there was a problem that the water resistance of the obtained silica gel was not sufficient, the production process was complicated, and the productivity was poor.

By the way, silica gel having various functions provided by supporting a specific foreign element as a simple substance and / or its compound is useful as various catalysts, antibacterial agents, high-performance adsorbents, separating agents and the like. There are some known conventional techniques for producing such a different element-supporting silica gel, but a technique for supporting various metals and catalytically active substances on conventional water glass silica gel (Patent Document 1 (antibacterial agent), Patent Document 2 ( (Olefin hydration catalyst), Patent Document 3 (olefin polymerization catalyst), etc., or a technique of post-supporting various elements on micellar template silica whose pores are controlled using templates (Patent Document 4, Patent) Reference 5)
Etc.

However, among the above-mentioned conventional techniques,
In this technique, although the manufacturing cost is low, the amount of impurities generally present in the obtained silica gel is large, and in addition, a high-purity silica gel carrier having a sufficiently controlled pore size of 20 nm or less is currently used. However, there is a problem that it does not exist. Further, in the technique, although the obtained silica gel has a narrow pore distribution, the production cost is high because the organic template is expensive, and unnecessary impurity metals are easily mixed due to the complicated production process. There are challenges. In addition, since the pore walls are very thin, structural strength is weak, physical properties change easily, and poor productivity is a problem.

[0011]

[Non-Patent Document 1] Kim et al., Ultrastable Mesostruct
ured Silica Vesicles Science, 282, p1302 (1998)

[Patent Document 1] Japanese Patent Laid-Open No. 62-113713

[Patent Document 2] Japanese Unexamined Patent Publication No. 9-30809

[Patent Document 3] Japanese Patent Laid-Open No. 5-155725

[Patent Document 4] JP-A-7-330642

[Patent Document 5] Japanese Patent Laid-Open No. 11-269213

[Patent Document 6] JP-A-5-254827

[Patent Document 7] Japanese Patent Laid-Open No. 10-296088

[0012]

From the above background, the amount of impurities is small, the purity of the target foreign element is high, the productivity is excellent, the pore size is controlled, and the sharp pore distribution is exhibited. Further, a different element-supporting silica gel having excellent physical property stability, that is, satisfying various characteristics in a well-balanced manner has been desired.

The present invention has been made in view of the above problems. That is, the object of the present invention is not only to have a large pore volume and specific surface area, but also to have a narrow pore distribution, which can contain a desired amount of a useful supporting element, and can suppress the amount of unnecessary metal impurities, and heat resistance. The purpose of the present invention is to provide a novel foreign-element-supporting silica gel having excellent properties, water resistance, physical property stability (thermal stability, etc.).

[0014]

Therefore, the present inventors have
As a result of intensive studies to solve the above problems, the different element-supporting silica gel manufactured by a specific method satisfies various characteristics in a well-balanced manner, and it was found that the above problems can be effectively solved, and the present invention was completed. Let

That is, the gist of the present invention is (a) pore volume.
Product is 0.3 to 1.6 ml / g, and (b) the specific surface area is
200-900m²/ G, and (c) modal diameter of pores
(D_{m ax}) Is less than 20 nm, and (d) the diameter is D_max±
The total volume of pores within the range of 20% is the total volume of all pores.
40% or more of (e) alkali metal and alkali
The total content of elements belonging to the group consisting of earth metals is 300p
pm or less, (f) Group 13, 14 and 1 of the periodic table
Of the elements belonging to the group consisting of Group 5 and transition metals,
At least the content of one kind of element is 0.1% or more,
(G) Group 13, 14 and 15 and transition metal
Of a simple substance and / or compound of an element belonging to the group consisting of
At least a part of it is supported on the surface of silica gel as particles or
Are retained, and (h) the particle size of the above-mentioned granules is
D_maxX2.5 or less, bearing different elements
Pertaining to silica gel.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. One feature of the foreign element-supporting silica gel of the present invention is that the pore volume and the specific surface area are in a range larger than usual. Specifically, the value of the pore volume is usually 0.3.
~ 1.6 ml / g range, preferably 0.4-1.5 m
1 / g range, more preferably 0.5-1.3 ml / g
And the value of the specific surface area is usually 200 to 900.
m ² / g range, preferably in the range of 200~800m ² / g, further preferably in the range of 200-700 ² / g. The values of these pore volume and specific surface area are measured by the BET method by nitrogen gas adsorption / desorption.

The different element-supporting silica gel of the present invention is
From the isothermal desorption curve measured by the nitrogen gas adsorption / desorption method, the EP
Barrett, LG Joyner, PH Haklenda, J. Amer. Ch
pore distribution curve calculated by the BJH method described in em.Soc., vol. 73, 373 (1951), that is, pore diameter d (nm)
With respect to the differential nitrogen gas adsorption amount (ΔV / Δ (logd);
V is the mode diameter (D _max ) on the plot of nitrogen gas adsorption volume) of less than 20 nm, and the lower limit is not particularly limited, but is preferably 2 nm or more. This means that the most frequent diameter (D _max ) of the pores of the different element-supporting silica gel of the present invention exists in a smaller range than that of ordinary silica gel.

Further, the different element-supporting silica gel of the present invention comprises
Most frequent diameter (D_max) Within ± 20% of the value
The total volume of pores is usually 40% or more of the total volume of all pores,
Characterized by the fact that it is more than 50%
It Also, the most frequent diameter (D _max) Around the value of
The total volume of pores in the range of ± 20% is the total volume of pores.
It is usually 90% or less. This is due to the foreign element loading of the present invention.
The diameter of the pores of silica gel is the most frequent diameter (D_max)
It means that the pores in the vicinity are aligned.

In relation to such characteristics, the different element-supporting silica gel of the present invention has a differential pore volume ΔV / Δ (log in the mode diameter (D _max ) calculated by the above BJH method.
d) is usually 2 to 20 ml / g, especially 3 to 12 ml / g
(In the above formula, d is the pore diameter (nm) and V is the nitrogen gas adsorption volume).
When the differential pore volume ΔV / Δ (logd) is included in the above range, it can be said that the absolute amount of pores aligned near the mode diameter (D _max ) is extremely large.

The different element-supporting silica gel of the present invention comprises
In addition to the above characteristics of the pore structure, it is preferable that the three-dimensional structure thereof is amorphous, that is, no crystalline structure is recognized. This means that when the foreign element-supporting silica gel of the present invention is analyzed by X-ray diffraction, no crystalline peak is substantially observed. In the present specification, silica gel which is not amorphous means 6 angstrom (Å Units d-spacing) in X-ray diffraction pattern.
It refers to one showing a peak of at least one crystal structure at a position beyond. Amorphous silica gel is much more productive than crystalline silica gel.

A further feature of the silica gel carrying different elements of the present invention is that the total content of elements (impurity elements) belonging to alkali metals or alkaline earth metals is usually 300 ppm or less, preferably 100 ppm or less, more preferably 50 ppm.
It is a very low purity of not more than ppm, most preferably not more than 30 ppm, and it has a very high purity. Such a small influence of impurities is one of the major factors by which the different element-supporting silica gel of the present invention can exhibit excellent properties such as high heat resistance and water resistance.

In addition to the above-mentioned various features, the foreign element-supporting silica gel of the present invention is a group of useful elements including groups 13, 14 and 15 of the periodic table and transition metals (useful foreign element group). Of the elements belonging to, the content of at least one element (target foreign element) is usually 0.1% or more, preferably 0.2% or more, more preferably 0.5% or more,
Particularly preferably, it is characterized by being 1% or more. Specifically, the target foreign element is, from the element species belonging to the useful foreign element group contained in the foreign element-supporting silica gel of the present invention, in order of increasing content, usually 4 types, preferably 3 types,
More preferably, it means 2 kinds, and particularly preferably 1 kind. Here, when two or more target foreign elements are contained, these elements may be contained in a total amount of 0.1% or more.
However, even if there are two or more target foreign elements, the content of at least one target foreign element is usually 0.2%.
It is preferably at least 0.5%, more preferably at least 1%.

The existence state of these target foreign elements is characterized in that they are basically carried or held as a simple substance and / or compound of the element on the surface of silica gel in the form of particles. Specifically, the particulate matter may be attached or adhered to the silica gel surface, or a part thereof may penetrate into the silica gel pore wall. In addition, at least a part of such a simple substance of the target foreign element and / or the granular material of the compound may be bonded to the silicon atom directly or through oxygen. Furthermore, the valence of these target foreign elements may take any value, and may exist in a form associated with other elements or compounds.

The manner in which the simple substance and / or the compound of these target foreign elements carried or held on the surface of silica gel have a granular shape can be observed by using a transmission electron microscope. The particle size of the granules is limited to a certain size or less because of being restricted by the silica gel pore size, but when loaded or held on the different element-supporting silica gel of the present invention, this upper limit is usually the most frequent diameter ( 2.5 times or less of D _max ). That is, the pore size of silica gel has a distribution width,
Since the maximum pore diameter that can be taken by the foreign element-supporting silica gel of the present invention is a value that is generally defined by D _max × 2.5, the maximum value of the particle diameter of the particulate matter supported or retained in the pores is also this value. It is less than or equal to the value. Further, the lower limit value takes various values depending on the type, amount, treatment method and the like of the supported element, but is generally 1 nm or more.

When the simple substance and / or compound of the target foreign element is present in a granular form in the pores, the simple substance and / or compound is atomized to nanoscale. Since nanoscale fine particles have various advantageous characteristics, they are preferable as a state of existence of the target foreign element. For example, as a generally known property, when a simple substance and / or a compound of a target foreign element is formed as fine particles, it has a large surface. Such properties are extremely preferable in applications where the physical properties of the target foreign element alone and / or the surface properties of the compound are utilized, because the utilization efficiency is extremely high. Also, as a generally known property, when the size of the particles of the target foreign element and / or the compound is reduced, a quantum effect may appear when a certain threshold is exceeded. By utilizing these properties, it becomes possible to give the material new physical properties such as a tunnel effect (Josephson effect) in which a current flows at a contact surface of a metal, a semiconductor, an insulator or the like. As described above, since the technique of utilizing nanoscale particles is very important industrially, the foreign element-supporting silica gel of the present invention in which nanoscale particles are formed in the pores is very preferable.

The foreign element-supporting silica gel of the present invention having the physical properties described above is substantially limited in its production method except that the silica hydrogel is not aged before the hydrothermal treatment for controlling the pores. Should not be.

The different element-supporting silica gel of the present invention comprises
It can be produced by a method of supporting a target foreign element on high-purity silica gel whose pores have been controlled. In this case, first, a simple substance of the target foreign element and / or its compound is introduced into the silica gel pores. Examples of the method include impregnation method <absorption method, pore-filling method, and “incipient wetness”, which are well known as catalyst preparation methods.
Method, evaporation to dryness method, spray method, etc.>, precipitation method <coprecipitation
Method, deposition method, kneading method, etc.>, ion exchange method, or any other known method may be used. Specifically, there is a method of immersing silica gel in an aqueous solution of a nitrate of a target foreign element, stirring, and then filtering and drying the silica gel. that time,
Hydrochloride, sulfate, acetate, alkoxides, etc. may be used in place of the nitrate of the target foreign element. Also, without filtration,
Water may be evaporated by heating. Besides this,
The target foreign element may be introduced by a method such as a mechanical mixing (mechanochemical) method or a vapor deposition method (chemical vapor deposition method, sputtering method).

After the target foreign element is introduced into the pores by the above-mentioned operation, the cross-linking reaction between the target foreign element and silica gel can be promoted by firing at 200 to 400 ° C. if necessary. . If necessary, the chemical state of the target foreign element may be changed by carrying out a chemical treatment such as oxidation or reduction after supporting the target foreign element.

The target foreign element can be carried on the silica gel obtained by hydrolyzing the silicon alkoxide and hydrothermally treating it without aging by the above method.
The form, the type of compound, and the amount of the compound are not particularly limited as long as the target foreign element expresses functionality, and a simple substance, a water-soluble salt, a solvent-soluble salt, or a complex compound of these target foreign elements. , A hydrolyzable compound or the like. In addition, from the viewpoint of obtaining highly pure foreign element-supporting silica gel, it is preferable to use a highly pure compound of the target foreign element. Further, high-purity silica gel as a carrier may be pretreated. For example, when a carbon content derived from silicon alkoxide, which is a raw material of silica gel serving as a carrier, is contained, it is usually 400 if necessary.
You may bake and remove at -600 degreeC. Further, in order to control the surface condition, firing may be performed at a temperature of up to 900 ° C.

Specific examples of the elements belonging to the group of elements (useful foreign elements) consisting of groups 13, 14, and 15 of the periodic table and transition metals, which are the objects of selection of the foreign elements for the purpose of the present invention, are as follows. Group 13 is B, Al, Ga, In, T
1, 14 group is C, Si, Ge, Sn, Pb, 15 group is N, P, As, Sb, Bi, and transition metal is Sc, T
i, V, Cr, Mn, Fe, Co, Ni, Cu, Zn,
Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, A
g, Cd, lanthanoids, Hf, Ta, W, Re, O
s, Ir, Pt, Au, Hg, actinides, Rf,
DB, Sg, Bh, Hs, Mt, etc. are mentioned. Among them, B, Al, Ga, In, Tl, Ge, Sn, Pb,
P, As, Sb, Bi, Sc, Ti, V, Cr, Mn,
Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, M
o, Tc, Ru, Rh, Pd, Ag, Cd, lanthanoids, Hf, Ta, W, Re, Os, Ir, Pt, A
u, Hg, actinides and the like are preferable because they are highly active and useful in various applications, and it is particularly preferable to form a simple substance and / or compound of these elements in a granular form.

Among these elements, B, Al, Ga, In, Tl, and
Fe, Ti, P, W, Mo, Zn, etc. are used as W, Mo, Tc, Re, Ru, as hydrogenation catalysts / dehydrogenation catalysts.
Os, Rh, Ir, Pd, Pt, Ag, Au, Ni, C
u, etc. are used for redox catalysts such as Ti, Zr, Hf,
V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co,
Ni, Cu, Zn, Sn, Ge, Pb, etc., Ti, Zn, W, Sn, Cd etc. for photocatalyst use, and Ti, Zr, Cr, Fe, Ge, Sb, B for polymerization catalyst use.
i, V, Mo, W, Mn, Co, Cu, Sc, Nb and the like are preferable.

When using a different element-containing silica gel for the purpose of these catalysts (especially solid acid catalyst / solid base catalyst), those having a wide pore distribution without controlling the pore size and impurity elements (especially alkali metal and If a high alkaline earth metal content is used, the catalytic activity will be poor and the life will be short. On the other hand, the different element-containing silica gel of the present invention,
Since the pore size is controlled, the pore distribution is narrow, and the content of impurity elements is low, excellent catalytic activity can be obtained when used for these catalyst applications, and it has a long life. Can be used for

Of course, the use of the elements belonging to the groups 13, 14 and 15 and the transition metals is not limited to the above-mentioned ones, but other uses such as antibacterial agents (Ti, Ag,
(Cu, Zn, etc.), water resistance improvement (stability improvement) applications (Z
r, Ti, etc.), phosphor applications (rare earths, lanthanides)
Needless to say, various uses can be mentioned.

The silicon alkoxide used as a raw material for the different element-supporting silica gel of the present invention includes trimethoxysilane, tetramethoxysilane, triethoxysilane, tetraethoxysilane, tetrapropoxysilane,
Examples thereof include tri- or tetraalkoxysilanes having a lower alkyl group having 1 to 4 carbon atoms such as tetrabutoxysilane, and oligomers thereof, but tetramethoxysilane, tetraethoxysilane and oligomers thereof are preferable. Since the above silicon alkoxide can be easily purified by distillation, it is suitable as a raw material for high-purity foreign element-supporting silica gel. The total content of the impurity elements (metal impurities) belonging to the alkali metal or the alkaline earth metal in the silicon alkoxide is usually preferably 100 p.
pm or less, more preferably 50 ppm or less. The content of these metal impurities can be measured by the same method as the general method for measuring the content of impurities in silica gel.

The hydrolysis of silicon alkoxide is usually 2 to 50 mol per mol of silicon alkoxide.
It is preferably carried out with 3 to 20 mol, particularly preferably 4 to 10 mol of water. In the middle of this step, a simple substance or a compound of the target foreign element is added by an arbitrary method, whereby the silicon alkoxide is hydrolyzed to generate a hydrogel of silica doped with the target foreign element and an alcohol. This hydrolysis reaction is usually performed at room temperature to 1
Although it is about 00 ° C, by maintaining the liquid phase under pressure,
It is also possible to work at higher temperatures. Moreover, at the time of hydrolysis, a solvent such as an alcohol which is compatible with water may be added, if necessary. Specifically, the carbon number is 1 to 3.
Lower alcohols, dimethylformamide, dimethylsulfoxide, acetone, tetrahydrofuran, methylcerolbu, ethylcerolbu, methylethylketone, and other organic solvents that can be arbitrarily mixed with water, but those that do not show strong acidity or basicity Is preferable because it can form a uniform silica hydrogel.

Silica gel having a crystal structure tends to have poor thermal stability in water, and when the silicon alkoxide is hydrolyzed in the presence of a template such as a surfactant used to form pores in the gel, The gel easily contains a crystalline structure. Therefore, in the present invention, it is preferable to hydrolyze in the absence of a template such as a surfactant, that is, under the condition that they do not exist in an amount sufficient to exert the function as a template.

The reaction time depends on the composition of the reaction solution (the kind of silicon alkoxide and the molar ratio with water) and the reaction temperature, and since the time until gelation differs, it is not generally specified. As a catalyst in the reaction system, acid, alkali,
Hydrolysis can be promoted by adding salts and the like. However, the use of such an additive causes aging of the produced hydrogel, as will be described later, and is not so preferable in the production of the foreign element-supporting silica gel of the present invention.

In the above hydrolysis reaction of the silicon alkoxide, the silicon alkoxide is hydrolyzed to form a silicate, and subsequently, the condensation reaction of the silicate occurs, the viscosity of the reaction solution increases, and finally gelation occurs. It becomes silica hydrogel. In order to produce the foreign element-supporting silica gel of the present invention, hydrothermal treatment is performed immediately without substantially aging the silica hydrogel so that the hardness of the hydrogel of silica produced by the above hydrolysis does not increase. is important. Hydrolysis of silicon alkoxide produces a soft silica hydrogel. Stable aging or drying of this hydrogel is followed by hydrothermal treatment to finally obtain silica gel with controlled pore characteristics. According to the above method, it is not possible to produce silica gel having physical properties defined in the present invention.

Immediately performing hydrothermal treatment on the hydrogel of silica produced by hydrolysis without substantially aging means that the soft state immediately after the hydrogel of silica is maintained is maintained. , Which means to be subjected to the following hydrothermal treatment. It is not preferable to add an acid, an alkali, a salt or the like to the hydrolysis reaction system of the silicon alkoxide, or to make the temperature of the hydrolysis reaction too strict, because the aging of the hydrogel proceeds. Further, in the post-treatment after the hydrolysis, washing, drying, leaving and the like should not take more temperature and time than necessary.

As a means for specifically confirming the aged state of the hydrogel, the hardness of the hydrogel measured by the method as described in the below-mentioned examples can be referred to. That is,
By subjecting a hydrogel in a soft state having a fracture stress of usually 6 MPa or less, preferably 3 MPa or less, more preferably 2 MPa or less to hydrothermal treatment, silica gel having physical properties defined by the present invention can be obtained.

As the condition of this hydrothermal treatment, the state of water may be liquid or gas, and may be diluted with a solvent or another gas, but liquid water is preferably used. The silica hydrogel is usually 0.1 to 10 times by weight, preferably 0.5 to 5 times by weight, particularly preferably 1 times.
~ 3 times by weight of water is added to form a slurry, usually 40 ~ 2
At a temperature of 50 ° C., preferably 50 to 200 ° C., usually 0.
It is carried out for 1 to 100 hours, preferably 1 to 10 hours.
Water used for hydrothermal treatment includes lower alcohols, methanol, ethanol, propanol, dimethylformamide (DMF), dimethylsulfoxide (DMSO),
Other organic solvents and the like may be included. Further, this hydrothermal treatment method is also applied to a material in which silica gel is formed in a film or layer form on a substrate such as particles, a substrate, or a tube for the purpose of producing a membrane reactor or the like. It is also possible to perform hydrothermal treatment by changing the temperature conditions using a reactor for hydrolysis reaction, but the optimum conditions are usually different between the hydrolysis reaction and the subsequent hydrothermal treatment. It is generally difficult to obtain the foreign element-supporting silica gel of the present invention.

When the temperature is increased under the above hydrothermal treatment conditions, the resulting silica gel tends to have a large pore size and a large pore volume. The hydrothermal treatment temperature is 100 to 20
It is preferably in the range of 0 ° C. Further, with the treatment time, the specific surface area of the obtained silica gel tends to gradually decrease after reaching the maximum once. Based on the above tendency, it is necessary to appropriately select the conditions according to the desired physical property values, but since hydrothermal treatment is for the purpose of changing the physical properties of silica gel, it is usually higher temperature conditions than the above hydrolysis reaction conditions. Preferably.

If the hydrothermal treatment temperature and time are set outside the above ranges, it will be difficult to obtain the different element-supporting silica gel of the present invention. For example, if the temperature of the hydrothermal treatment is too high, the pore size and pore volume of silica gel become too large, and the pore distribution also widens. Conversely, if the temperature of hydrothermal treatment is too low,
The silica gel thus produced has a low degree of crosslinking, is poor in thermal stability, and tends to have no peak in the pore distribution.

When the hydrothermal treatment is performed in ammonia water, the same effect can be obtained at a lower temperature than that in pure water. Further, when hydrothermal treatment is carried out in ammonia water, the silica gel finally obtained generally becomes hydrophobic as compared with the case of treatment in pure water, but it is usually 30 to 250 ° C., preferably 40 to 200 ° C. Hydrothermal treatment at high temperature makes it particularly hydrophobic. The ammonia concentration in the ammonia water here is preferably 0.001 to 10
%, Particularly preferably 0.005 to 5%.

The hydrothermally treated silica hydrogel is usually dried at 40 to 200 ° C, preferably 60 to 180 ° C. The drying method is not particularly limited and may be a batch type or a continuous type, and can be dried under normal pressure or reduced pressure. Further, after pulverizing and classifying as necessary, the above-mentioned method is carried out to introduce the target foreign element into the pores, thereby finally obtaining the target foreign element-supporting silica gel of the present invention. In addition, as described above, post-treatments such as calcination for promoting the crosslinking reaction and chemical treatments such as redox may be performed, if necessary.

The foreign element-supporting silica gel of the present invention can be used for any purpose other than the conventional use of silica gel. Among them, the conventional uses include the following.

For example, in the field of application used for manufacturing and treating products in industrial facilities, various catalysts and catalyst carriers (acid-base catalysts, photocatalysts carrying titanium oxide etc., noble metal catalysts, etc.), wastewater / waste oil treatment agents , Odor treating agents, gas separating agents, industrial desiccants, bioreactors, bioseparators, membrane reactors and the like.
Examples of building materials include humidity control agents, soundproofing / sound absorbing materials, refractories, and heat insulating materials. Further, in the application of the air conditioning field, a desiccant air conditioner humidity control agent, a heat pump heat storage agent and the like can be mentioned. In the application field of paints / inks, examples include matting agents, viscosity adjusting agents, chromaticity adjusting agents, anti-settling agents, antifoaming agents, ink strike-through preventing agents, stamping foils, and wallpaper. In the field of application of additives for resins,
Anti-blocking agent for films (polyolefin film, etc.), plate-out prevention agent, silicone resin reinforcing agent, rubber reinforcing agent (for tires / general rubber, etc.), fluidity improver, powder resin anti-caking agent, Examples thereof include printability improving agents, matting agents for synthetic leather and coating films, adhesive / adhesive tape fillers, translucency adjusting agents, antiglare adjusting agents, and fillers for porous polymer sheets. In the field of papermaking applications, thermal paper fillers (such as dust adhesion preventives), ink jet paper image improving fillers (ink absorbing agents, etc.), diazo photosensitive paper fillers (photosensitive density improving agents, etc.), tracing papers. Writability improver, coated paper filler (writability, ink absorption,
The anti-blocking property improving agent), the electrostatic recording filler, etc. In the field of food applications, filter aids for beer, hanging agents for fermented products such as soy sauce, sake, and wine, stabilizers for various fermented beverages (removal of turbidity factor protein and yeast, etc.), food additives, powdered food products, etc. Applications include anti-caking agents. In the field of medicines and agricultural chemicals, tableting aids for medicines, grinding aids, dispersion / medical carriers (dispersion / sustained release / improvement of delivery property, etc.), pesticide carriers (oil pesticide carrier /
Improvement of hydration dispersibility, sustained release / improvement of delivery, etc., pharmaceutical additives (anti-caking agent / granularity improving agent, etc.), agricultural chemical additives (anti-caking agent, anti-settling agent, etc.), etc. Can be mentioned. In the field of separation materials, packing materials for chromatography, separation agents, fullerene separation agents, adsorbents (proteins, pigments, odors, etc.),
Applications include dehumidifying agents. In the field of agriculture, feed additives and fertilizer additives can be mentioned. As other uses, in the field of daily life, humidity control agents, desiccants, cosmetic additives, antibacterial agents, deodorant / deodorant / fragrance agents, detergent additives (surfactant powdering, etc.), abrasives (toothpaste) Etc.), powder fire extinguishing agents (powder graininess improving agents, anti-caking agents, etc.), antifoaming agents, battery separators and the like.

Among these, particularly controlled pore characteristics are required, and it is required that there is little change in physical properties over a long period of time, and it is possible to impart a function by supporting a specific useful foreign element alone and / or a compound. In the required fields, specifically, the foreign element-supporting silica gel of the present invention can be suitably used as, for example, various catalysts, antibacterial agents, high-performance adsorbents, separating agents, fillers, and the like.

[0049]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

(1) Hardness measurement of silica hydrogel: 5
After the silicon alkoxide was reacted with 6 moles of water in an L separable flask and the temperature of the reaction solution reached the boiling point of the alcohol produced by the reaction, the reaction solution was withdrawn from the flask and the withdrawn reaction solution with a glass of 50 cc. A certain amount (about 20 mm in liquid depth) was transferred to a screw tube made of a liquid, sealed and kept in a water bath controlled at a substantially constant temperature, and the rupture strength was measured with a digital force gauge (A &. Made by Dee, model: A
D-4935). A probe (a round bar made of stainless steel and having a diameter of 5 mm) is attached to the measuring instrument,
The hydrogel retained in the container is crushed by being pushed slowly into the hydrogel. The breaking stress was defined as the maximum stress value shown until the hydrogel was compressed and broken.

The measurement results are shown in FIG. FIG. 1 is a plot of the common logarithm of the aging time of silica hydrogel on the horizontal axis and the fracture stress on the vertical axis. From FIG. 1, it can be seen that the fracture stress increases with the aging time and that the aging rate depends on the temperature.

(2) Analytical method for silica gel supporting different elements: 2-1) Pore volume, specific surface area: AS manufactured by Kantachrome
The BET nitrogen adsorption isotherm was measured at -1, and the pore volume and specific surface area were determined. Specifically, the pore volume is the relative pressure P / P _0.
= 0.98, the specific surface area is P / P ₀ =
BET from the nitrogen adsorption amount of 0.1, 0.2, 0.3
It was calculated using the multipoint method. In addition, the BJH method was used to determine the pore distribution curve and the differential pore volume at the mode diameter (D _max ). The distance between the measured relative pressure points was 0.025.

2-2) Powder X-ray diffraction: RA manufactured by Rigaku Denki Co., Ltd.
The measurement was performed using a D-RB device and CuKα as a radiation source. Divergence slit 1deg, scattering slit 1deg,
The light receiving slit was 0.15 mm.

2-3) Content of target foreign element and metallic impurities: Hydrofluoric acid was added to 2.5 g of the sample to heat it to dry it, and then water was added to make 50 ml. ICP emission spectrometry was performed using this aqueous solution. In addition, sodium and potassium were analyzed by the flame flame method.

2-4) Transmission electron microscope (Transmission
Observation by Electron Microscope (TEM): The sample was lightly crushed in a mortar for 1 minute, ultrasonically dispersed in ethanol, dropped on a microgrid, and naturally dried. Using a Hitachi H-9000UHR transmission electron microscope,
A TEM photograph was taken under the conditions of 300 kV and a diaphragm of 4,800,000 times. On the obtained photograph, the average value of the major axis of the carried granular material was determined, and this was taken as the particle diameter of the granular material.

(3) Production and evaluation of foreign-element-supporting silica gel: Example 1: (Preparation of carrier silica gel) In a 5 L separable flask (with a jacket) made of glass and equipped with a water-cooled condenser open to the atmosphere. Then, 1000 g of pure water was charged. While stirring at 80 rpm, 1400 g of tetramethoxysilane was charged into this over 3 minutes. The water / tetramethoxysilane molar ratio is about 6. Hot water at 50 ° C was passed through the jacket of the separable flask. The stirring was continued, and when the contents reached the boiling point, the stirring was stopped. 50 hours on the jacket for about 0.5 hours
The sol produced by passing warm water at ℃ was gelled. Then, the gel was immediately taken out, and the gel was crushed through a nylon net having an opening of 600 microns to obtain a powdery wet gel (silica hydrogel). This hydrogel 45
0 g and 450 g of pure water were charged into a 1 L glass autoclave, and hydrothermal treatment was carried out at 150 ° C. for 3 hours. After hydrothermal treatment for a predetermined time, No. It was filtered with a 5A filter paper, and the filter cake was dried under reduced pressure at 100 ° C. to a constant weight without washing with water. The physical properties of the resulting silica gel (support silica gel of Example 1) are shown in Table 1 below.

(Preparation of catalyst precursor) 1.67 g of palladium chloride was weighed in a 100 ml Erlenmeyer flask and 25%
After heating and dissolving with 27 ml of ammonia water, return to room temperature,
This was made up to 60 ml with aqueous ammonia used.
This is a palladium chloride aqueous solution. 50 g of the above carrier silica gel is placed on a rotating drum, and 60 ml of the above palladium chloride aqueous solution (this is an amount such that the amount of palladium metal with respect to the carrier is 2.0% by weight) is rotated. Sprayed onto the upper carrier. continue,
This powder was taken out of the drum and dried at 80 ° C.

(Alkali treatment of catalyst precursor) This catalyst precursor was placed on a rotating drum, and 2% ammonia water 60 was added.
ml was sprayed in the same way. The volume of the alkaline aqueous solution is the same as the pore volume of the carrier. Further, the catalyst was washed with pure water to remove chlorine ions on the catalyst. When the catalyst was dispersed with pure water, the supernatant liquid when left to stand was transparent and palladium was not eluted.

(Reduction Treatment) 20 g of the catalyst obtained by the above method was treated under a hydrogen stream at 200 ° C. under a hydrogen flow rate of 57 l / Hr for 5 hours. The obtained catalyst was washed with water and then vacuum dried at 80 ° C. As a result, 2.0
A catalyst (silica gel supporting different elements) in which palladium was supported on silica by weight% was obtained. The physical properties of the resulting foreign element-supporting silica gel (silient element-supporting silica gel of Example 1) are shown in Table 2 below.

According to the powder X-ray diffraction pattern, 2θ ≦ 5 deg
In the range of, no peak due to the periodic structure was observed. When the metal content was analyzed, palladium as the target foreign element was 2.0% by weight, while sodium as the impurity element was 0.2 ppm and potassium was 0.1%.
ppm and calcium were 0.1 ppm, and other metal elements were not detected. Moreover, the particle size of the supported particles was uniform, and all were D _max × 2.5 or less, and there were no coarse particles. Therefore, the different element-supporting silica gel of Example 1 supports palladium in a highly dispersed state and can be used as a hydrogenation catalyst having high reaction activity.

Comparative Example 1: Silica gel for catalyst carrier manufactured by Fuji Silysia Chemical Co., Ltd. CARIACT G-6 was used as a carrier, an experiment was conducted under the same conditions as in Example 1, and silica gel supporting palladium as the target foreign element was carried out. Got The physical properties of the above-mentioned carrier silica gel (support silica gel of Comparative Example 1) used are shown in Table 1 below, and the physical properties of the obtained different element-supporting silica gel (Comparative Example 1-supporting silica gel) are shown in Table 2 below. Shown in. According to the powder X-ray diffraction pattern, 2θ
In the range of ≦ 5 deg, no peak due to the periodic structure was observed. Analysis of the metal content revealed that the target foreign element, palladium, was 2.0% by weight, whereas the impurity element aluminum was 14 ppm, sodium 165 ppm, potassium 20 ppm, calcium 162 ppm, and magnesium 33 ppm. , Titanium 259ppm, iron 25ppm, chromium 4ppm
And, it contained a large amount of impurity elements other than the target foreign element. In addition, the size of the supported particles varies slightly, and D _max
Coarse particles exceeding 2.5 were observed.

Thermal stability test of silica gel in water: 20 g of each of the different element-supporting silica gel samples of Example 1 and Comparative Example 1
Pure water was added to each to prepare 40 wt% slurries. Approximately 40 ml of the slurry prepared above was placed in a stainless steel micro bomb having a volume of 60 ml, sealed, and immersed in an oil bath at 200 ± 1 ° C. for 3 hours. A part of the slurry was extracted from the micro bomb and the powder was collected by filtration. The filter cake was vacuum dried at 100 ° C. for 5 hours. The results of measuring the specific surface area of this sample are shown in Table 2 below. Compared with the foreign element-supporting silica gel of Comparative Example 1, the foreign element-supporting silica gel of Example 1 was judged to be more stable because the specific surface area was less reduced.

[0063]

[Table 1]

[0064]

[Table 2]

[0065]

INDUSTRIAL APPLICABILITY The novel foreign element-supporting silica gel of the present invention has a narrow pore distribution as compared with the conventional foreign element-supporting silica gel and can carry a desired amount of a useful element, and an unnecessary metal. The amount of impurities can be suppressed,
Moreover, it is also excellent in heat resistance, water resistance, physical property stability (heat stability, etc.). Further, due to the sharp pore distribution of the carrier silica, the supported particles are uniformly and highly dispersed and retained on the surface of the pores, and exhibit higher activity than conventional silica gel.

[Brief description of drawings]

1 shows silica hydrogels at 35 ° C., 45 ° C. and 55 ° C.
It is a figure which shows the relationship between each aging time at the time of aging each temperature of ° C, and the fracture stress of hydrogel at that time.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4G072 AA35 AA38 CC10 GG02 HH30                       JJ09 MM01 QQ06 QQ09 RR05                       SS14 TT01 TT09 TT19 TT20                       UU15

Claims (14)

[Claims] 1. (a) Pore volume of 0.3-1.6 ml /
g, (b) specific surface area is 200 to 900 m ² / g, (c) pore mode diameter (D _max ) is less than 20 nm, and (d) diameter is within D _max ± 20%. The total volume of pores within is 40% or more of the total volume of all pores,
(E) The total content of elements belonging to the group consisting of alkali metals and alkaline earth metals is 300 ppm or less,
(F) The content of at least one kind of the elements belonging to the group consisting of Groups 13, 14 and 15 of the periodic table and transition metals is 0.1% or more, and (g) the above 13
At least a part of a simple substance and / or a compound of an element belonging to the group consisting of Group 14, Groups 14 and 15 and transition metals is supported or retained as a granular material on the surface of silica gel, and (h) the granular material Has a particle size of D _max × 2.
A different element-supporting silica gel, which is 5 or less. 2. The foreign element-supporting silica gel according to claim 1, wherein the particle size of the granular material is 1 nm or more. 3. The foreign element-supporting silica gel according to claim 1 or 2, wherein at least a part of the granular material is bonded to a silicon atom directly or through oxygen. 4. The foreign-element-supporting silica gel according to claim 1, which is amorphous. 5. The total content of elements belonging to the group consisting of the alkali metal and alkaline earth metal is 100 ppm.
The foreign element-supporting silica gel according to any one of claims 1 to 4, characterized in that: 6. The content rate of at least one element of the elements belonging to the group consisting of the groups 13, 14 and 15 and the transition metals is 0.2% or more. Item 6. The different element-supporting silica gel according to any one of items 1 to 5. 7. The foreign element-supporting silica gel according to claim 1, which has a pore volume of 0.4 to 1.5 ml / g. 8. The foreign-element-supporting silica gel according to claim 1, which has a specific surface area of 200 to 800 m ² / g. 9. The foreign element-supporting silica gel according to claim 1, wherein the mode diameter (D _max ) of the pores is 2 nm or more. 10. The total volume of pores having a diameter of D _max ± 20% or less is 50% or more of the total volume of all pores, and the total volume thereof is any one of claims 1 to 9. The different element-supporting silica gel described. 11. The foreign element according to claim 1, wherein the content of the element belonging to the group consisting of the alkali metal and the alkaline earth metal is 50 ppm or less. Supported silica gel. 12. The foreign element according to claim 1, wherein the content of the element belonging to the group consisting of the alkali metal and the alkaline earth metal is 30 ppm or less. Supported silica gel. 13. The foreign element-supporting silica gel according to claim 1, wherein the differential pore volume at the mode diameter (D _max ) is 2 to 20 ml / g. 14. The method according to claim 1, wherein the silicon alkoxide is produced through a step of hydrolyzing a silicon alkoxide.
The different element-supporting silica gel according to any one of 3 above.