JP2001046877A - Solid acid catalyst, gas removing member using the same and production of them - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a solid acid catalyst capable of efficiently removing a malodor and capable of keeping malodor removing capacity over a long period of time by making a compd. containing at least one structure selected from magnesium silicate and aluminum silicate carry fine particles of a transition metal oxide. SOLUTION: A solid acid catalyst is formed by making a compd. containing at least one structure selected from magnesium silicate (2MgO.6SiO2.xH2O) and aluminum silicate (Al3O3.9SiO2.xH2O) carry fine particles of transition metal oxide. The particle size of the fine particles is mainly set to 0.001-1 μm. Further, as a binder, colloidal silica is added. The solid acid catalyst is produced by dispersing particles comprising a compd. containing at least one structure selected from magnesium silicate and aluminum silicate in a solvent under an acidic condition and mixing them with fine particles of a transition metal oxide to prepare a synthetic suspension.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a solid acid catalyst, a gas removing member and a method for producing the same, and more particularly to a composition used for reducing odor.

[0002]

2. Description of the Related Art Conventionally, various methods have been sought for removing odors, such as ammonia,
Products are commercially available that remove methyl mercaptan, hydrogen sulfide, methyl sulfide, methyl disulfide, trimethylamine, acetaldehyde, styrene and the like. Techniques for removing these odors include adsorption, absorption, combustion, ozone oxidation, and masking. Activated carbon is most often used for the adsorption treatment. In addition, the absorption method is performed by utilizing the chemical reactivity of the substance to be treated.
Alkaline washing is effective for each acidic compound.

[0003]

However, in the above-mentioned various methods for removing bad odors, since adsorption and absorption of bad odors are used, when the amount of chemicals used for removal is limited, The effect of removing odors is not always sufficient,
There is a problem that the removal efficiency is reduced according to the degree of adsorption or absorption. In particular, in air purifiers that are frequently used in recent years, the installation space is limited and the installation method is also limited, so that the odor removal performance greatly changes over time. Is difficult. In addition, when using an absorption method (chemical reaction) having a high odor removal performance, it is necessary to use different absorbents for the basic compound and the acidic compound. Alternatively, it is necessary to use an absorbent compatible with a basic compound and an absorbent compatible with an acidic compound in combination, and there is a problem that it is difficult to use.

Accordingly, the present invention has been made to solve the above-mentioned problem, and an object of the present invention is to efficiently remove bad odors and to maintain the odor removing performance for a long time even with a limited amount. It is to provide a novel composition which can be used. Another object of the present invention is to provide a novel composition which is highly effective against both basic and acidic odors.

[0005]

[MEANS FOR SOLVING THE PROBLEMS]
The present invention relates to magnesium silicate (2MgO.6SiO). ₂
・ XH₂O) and aluminum silicate (Al₂O₃・ 9Si
O₂・ XH₂At least one structural part selected from O)
Particles of transition metal oxide for compounds containing
This is a solid acid catalyst.

According to the present invention, magnesium silicate and silica
At least one structural part selected from aluminum phosphate
Particles of transition metal oxide supported on compounds containing
To prevent any basic or acidic odor
Can be efficiently removed, and the removal
It is possible to obtain a composition that can maintain efficiency for a long time.
it can. This composition contains magnesium silicate or aluminum silicate
Due to the adsorption performance that minium originally has as an adsorbent,
To capture and adsorb odorous molecules,
Transition supported in the structure of nesium or aluminum silicate
The transfer metal oxide particles act as promoters
The catalyst function is activated by magnesium silicate or
Is the acid point on the surface of the aluminum silicate structure
(Solid acid) chemically displaces the odorous molecules,
It is considered to be understood. Therefore, just suck
Unlike absorption that involves dressing and chemical reactions,
The odor is decomposed and removed, so even a limited amount is effective.
The effect can be exhibited efficiently and for a long time.
In addition, due to the above structure, it also exhibits sufficient antibacterial power
Can be. In this case, the transition metal oxide is titanium oxide
(Titanium dioxide), especially
Fine particles formed by a synthetic method are preferred.
As the transition metal oxide, as a transition metal oxide
It is preferable that the substance is stable under normal environment.
For example, titanium oxide (TiO, Ti₂O₃, TiO₂),acid
Magnesium oxide, aluminum oxide, manganese oxide (M
nO, Mn₂O₃, MnO₂, Mn₃O₄, Mn
₂O₇), Iron oxide (FeO, Fe₂O₃, Fe₃O ₄)
Are typical. Also, other stable transitions
Sc, V, Cr, Co, Ni, C as metal oxides
u, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh,
Pd, Ag, Cd, Hf, Ta, W, Re, Os, I
There are oxides of r, Pt, Au and Hg. In addition,
The materials include the above magnesium silicate and aluminum silicate
And each exist independently, or
Structural parts of magnesium silicate and aluminum silicate
It may have a structure in which the parts are combined.
Of course, a compound that is magnesium silicate
Even if the compound that is minium just physically coexists
Good. All of the above various compounds are synthesized by chemical synthesis.
It is preferable that it is formed.

In the present invention, it is preferable that the fine particles have a particle diameter mainly in the range of 0.001 to 1 μm. According to the present invention, the use of the fine particles having a particle size in the range of 0.001 to 1 μm makes it possible to particularly effectively decompose and remove the bad odor. By using fine particles having a fine particle size as described above, it is easy to enter the structure of magnesium silicate or aluminum silicate,
Since many transition metal oxides are supported in the structure, it is considered that the catalytic action against the malodor can be further activated.

In the present invention, it is preferable that colloidal silica is contained as a binder. According to the invention,
By using colloidal silica as a binder, it is easy to hold the catalyst on various objects without hindering the above-mentioned catalytic action, and it is possible to easily adhere to a gas-permeable substrate such as a nonwoven fabric.

The gas removing member of the present invention is obtained by holding the solid acid catalyst described in each of the above inventions on a gas-permeable base material. Even if the solid acid catalyst is used in a small amount, it exerts a sufficient odor-decomposing action, so that a strong gas removing member can be easily formed simply by holding it on a substrate. In addition, it is desirable that the substrate is a gas-permeable substrate such as a nonwoven fabric, paper, cloth, or a net.

Next, the method for producing a solid acid catalyst of the present invention comprises:
Particles comprising a compound containing at least one structural portion selected from magnesium silicate and aluminum silicate are dispersed in a solvent under acidic conditions and mixed with fine particles of transition metal oxide to form a synthetic suspension. Features.

According to the present invention, magnesium silicate or aluminum silicate can be used as an adsorbent by itself, and its liquidity is 7 to 10 at pH and is on the alkaline side. Even if it is put into a solvent, it is easy to aggregate and may precipitate, which makes handling difficult.On the other hand, by putting particles of magnesium silicate or aluminum silicate in a solvent under acidic conditions, Are easily dispersed, and a synthetic suspension having excellent stability can be obtained. Therefore, the handling becomes easy, and a solid acid catalyst having stable quality can be formed. Here, the average particle size of the particles is 3 to 50.
The average particle diameter of the transition metal oxide fine particles is preferably 0.001 to 1 μm.

In the present invention, it is preferable that the synthetic suspension is dried and solidified. According to the present invention, the solidification facilitates installation at various installation locations, and also allows the solidification to be performed on various base materials, so that a wide range of installation modes can be realized.

In the present invention, it is preferable to form the synthetic suspension by mixing particles comprising the compound with an acidic suspension containing the fine particles. According to the present invention, a synthetic suspension can be obtained extremely easily and stably by mixing particles comprising the above compound into an acidic suspension containing titanium oxide particles.

In the present invention, the synthetic suspension preferably contains colloidal silica as a binder. According to the present invention, by containing colloidal silica as a binder, various substances can be easily and strongly applied only by coating and drying the synthetic suspension without lowering the catalytic ability of the solid acid catalyst. Can be fixed.

In the present invention, the particles of the compound are dispersed in a solvent under an acidic condition, and the particles are diluted with a liquid mainly composed of at least one selected from water and alcohols. Preferably, it is formed. According to the present invention, the solid acid catalyst is formed by dispersing particles of the compound in a solvent under an acidic condition and then diluting with a liquid mainly composed of at least one selected from water and alcohols. It is considered that the composition of the solid acid catalyst can be changed, and the solid state of the solid acid catalyst and the surface state can be changed, thereby optimizing the catalytic ability. Further, the transparency and hardness of the solid acid catalyst, the pH and volatility of the synthetic suspension, and the like can be adjusted by the dilution ratio. In this case, it is particularly preferable to disperse the particles made of the compound in a solvent under an acidic condition and to perform dilution after mixing the fine particles from the viewpoint of ensuring the stability of the suspension.

Further, in the method for producing the gas removing member, the above-mentioned synthetic suspension is formed by using each of the above-mentioned production methods, and the above-mentioned synthetic suspension is applied to a substrate and dried. In addition, it is desirable that the substrate is a gas-permeable substrate such as a nonwoven fabric, paper, cloth, or a net.

The weight ratio of magnesium silicate or aluminum silicate to the above fine particles can achieve the odor gas removal performance in a relatively wide range. : 1, preferably in the range of 0.5: 10 to 5: 1 in order to obtain high removal performance and sustained removal.

[0018]

DETAILED DESCRIPTION OF THE INVENTION Magnesium silicate (2MgO.6)
SiO ₂ xH ₂ O) and aluminum silicate (Al ₂ O ₃₎
· 9SiO ₂ · xH 2 _O) has a relatively large specific surface area, since they share the acidic sites and basic sites on the surface, chemisorption (reactive adsorption) and physical adsorption and occurs at the same time I do. This is different from the SiO ₂ —Al ₂ O ₃ catalyst conventionally used in petroleum refining and the like, in which the surface in the crystal structure has a structure similar to SiO ₂ , but SiO ₄ ( It is considered to have a structure similar to zeolite (a network structure in which the vertices of tetrahedrons are bonded to each other), and also exhibits properties similar to zeolite. Although SiO ₂ is basic in nature, the above-mentioned magnesium silicate and aluminum silicate contain a solid portion showing acidity in the crystal, that is, a large amount of solid acid.
This can be confirmed by showing an acidic color when methylene blue is dropped on these.

The above magnesium silicate and aluminum silicate can be obtained, for example, as Kyoward 600 (magnesium silicate) and Kyoward 700 (aluminum silicate) (both manufactured by Kyowa Chemical Industry Co., Ltd.). These are all particles formed by a chemical synthesis method, and have a minimum particle size of 3 to 5 μm and a maximum particle size of 40 to
It has a particle size distribution in the range of 400 μm. In addition,
Magnesium silicate and aluminum silicate may be eutectic (the magnesium oxide and aluminum oxide are partially replaced).
Further, particles obtained by simply mixing particles of magnesium silicate and particles of aluminum silicate may be used. These are usually considered to have an amorphous crystalline structure (amorphous structure), but the detailed structure is unknown. The average particle size is 3 to 500 μm for convenience of constituting a suspension.
m is preferable.

[0020] In this embodiment, the magnesium silicate _{(2MgO · 6SiO 2 · xH 2} O), or particles of aluminum silicate _{(Al 2 O 3 · 9SiO 2} · xH 2 O) are dispersed in a solvent, the By mixing the transition metal oxide particles in the state, the transition metal oxide particles are supported in the crystal structure of the magnesium silicate or aluminum silicate particles, and the synthesized suspension thus formed is dried. And solidify.

Here, an ordinary environment as a transition metal oxide is used.
It is preferably a substance that is stable under
Tan (TiO, Ti₂O₃, TiO₂), Magnesium oxide
, Aluminum oxide, manganese oxide (MnO, Mn
₂O₃, MnO₂, Mn₃O ₄, Mn₂O₇),iron oxide
(FeO, Fe₂O₃, Fe₃O₄) Are typical
It is. Other stable transition metal oxides
And Sc, V, Cr, Co, Ni, Cu, Zn, Y, Z
r, Nb, Mo, Tc, Ru, Rh, Pd, Ag, C
d, Hf, Ta, W, Re, Os, Ir, Pt, Au,
Hg oxide is present. The most preferred of these
Is titanium oxide (titanium dioxide), a specific example of which is
This is described in the following examples. Such transition metal acids
At least magnesium silicate or
Small enough to be supported in the structure of aluminum silicate
It is preferred to have a particle size, usually the average particle size
Is preferably 1 μm or less, more preferably 0.001 μm or less.
It is desirable to have an average particle size in the range of
However, it has a particle size distribution that mainly spreads within this range.
Just do it. The particle size of less than 0.001 μm is the main particle size distribution
Is difficult to obtain.
Bonding with the structure of magnesium silicate or aluminum silicate
And act as a co-catalyst to be described later.
Because it becomes hard. However, in the present invention, 0.0
That fine particles having a particle size outside the range of 01 to 1 μm exist.
It is not excluded.

As the supply source of the titanium oxide particles, those prepared as a slurry (suspension) liquid can be used in order to assist the dispersion of magnesium silicate or aluminum silicate particles under acidity described later. Such a device includes, for example, ST-K01 and ST-K03 (manufactured by Ishihara Sangyo, product number). In this case, the particle size distribution of fine particles of titanium oxide (which is titanium dioxide) is mainly 0.001 to 0.5 μm, and is formed by a chemical synthesis method. In addition, ST-K01 and ST
-K03 contains colloidal silica as an inorganic binder and exhibits strong acidity. Specifically, the solid content concentration is 10%,
The weight ratio of titanium oxide to the inorganic binder (colloidal silica) is 50:50, the pH is 1.5 due to the inclusion of nitric acid, the alcohol and water are used as the solvent, and the viscosity is 1 to 3 cps. In addition, as an inorganic binder shown below,
Colloidal silica in the above slurry liquid can be used.

With respect to the weight ratio of magnesium silicate or aluminum silicate to titanium oxide, the odor gas removing performance can be obtained in a relatively wide range, but the weight ratio is 0.001: 1 to 10: 1. It is preferably within the range, and particularly preferably within the range of 0.5: 10 to 5: 1 in order to obtain a high and continuous removal performance.

In the present embodiment, it is preferable that the above-mentioned synthetic suspension contains a binder (binder). By incorporating a binder, a sufficient adhesion to various substrates can be obtained when the synthetic suspension is dried and solidified. As the binder, an inorganic binder such as silica (silicic acid) and an organic binder such as an acrylic resin can be used. In particular, by using colloidal silica, it is easily bonded to the structure of magnesium silicate or aluminum silicate, and is stable for a long time. A suspension can be obtained. A primer containing colloidal silica as the most preferable inorganic binder includes Primer A (trade name, manufactured by Colcoat Co., Ltd.). The primer A is a silica dispersion containing colloidal silica and mainly containing isopropyl alcohol as a solvent.

When the above-mentioned particles of magnesium silicate or aluminum silicate are dispersed in a solvent, they may be aggregated or precipitated, and if the particles are aggregated or precipitated, the handling becomes difficult. Preferably, the aluminum particles are dispersed in the solvent. To control the acidity, an acidic liquid containing a binder may be used, or an acid may be separately added during mixing to maintain the acidity. It is particularly desirable that the acidity be 3 or less at pH.

As the solvent, water, alcohols,
Alternatively, a mixed solution of water and alcohol (alcohol-containing water) can be used. After the particles of magnesium silicate or aluminum silicate are dispersed in a solvent as described above, the particles can be further diluted with water, alcohols, or a mixture thereof. The synthetic suspension in which the particles of magnesium silicate or aluminum silicate and the fine particles of titanium oxide are mixed and dispersed in a solvent may be further diluted with water, alcohols, or a mixture thereof. In addition, since it takes time to dry when only water is used as the diluting solvent, in order to enhance the stability and the drying property of the coating liquid, alcohol is selected from various alcohols such as methanol, ethanol and isopropyl alcohol. It is preferable to use one or more of them.

Example 1 Next, a specific example of the above embodiment will be described. With respect to 100 parts by weight of the above titanium oxide slurry solution (ST-K03), KYOWARD 600 (specifically, KYOWARD 600
In addition, 600S and 600BUP-S may be used. ) Is added and stirred. At this time, since the titanium oxide slurry liquid is strongly acidic, the particles of magnesium silicate or aluminum silicate do not aggregate, and the synthetic suspension A in a good dispersion state is formed.

Next, the synthetic suspension A is diluted with water to form a synthetic suspension B. At this time, it may be diluted with alcohols. The dilution ratio was 6 types shown in Table 1 below.

[0029]

[Table 1]

Next, a non-woven fabric (7
(0 mm × 70 mm, weight: about 1 g) was immersed, pulled up, and dried at room temperature for 20 hours.

[Embodiment 2] As in Embodiment 1 described above,
100 of the above titanium oxide slurry liquid (ST-K03)
For weight parts, KYOWORD 700 (specific product names other than KYOWORD 700, 700PL, 70PL
It may be 0PH, 700PEL, 700SL, or 700SN. ) Is added and stirred. At this time, since the titanium oxide slurry liquid is strongly acidic, the particles of magnesium silicate or aluminum silicate do not aggregate, and the synthetic suspension A in a good dispersion state is formed. In addition, this synthetic suspension A was prepared using the six types of dilution ratios shown in Table 1 above.
To prepare a synthetic suspension B. Also in this example, as in Example 1, the nonwoven fabric was immersed in the synthetic suspension B, pulled up, and dried at room temperature for 20 hours.

The amount of the non-woven fabric immersed in the synthetic suspension B prepared in Examples 1 and 2 described above and adhered in a solidified state (hereinafter, referred to as a supported amount) is as shown in Table 2 below. became. Here, “〜” in Table 2 corresponds to the case where a nonwoven fabric immersed in the synthetic suspension B shown in “〜” of Table 1 and dried is used.

[0033]

[Table 2]

The non-woven fabric formed as described above was
Put it in a freezer bag with a sleeve with a cock of mm × 203 mm, completely close it, and introduce a sulfur-based or nitrogen-based odor gas (hydrogen sulfide, trimethylamine) from the above-mentioned sleeve to an initial concentration of 200 ppm. The odor concentration was decayed by a gas detector every time. Table 3 (Example 1) and Table 4 (Example 2)
Shown in

[0035]

[Table 3]

[0036]

[Table 4]

Here, the judgment results shown in Tables 3 and 4 indicate that the double circle indicates that both hydrogen sulfide and trimethylamine are 1 ppm or less, and the circle indicates that both hydrogen sulfide and trimethylamine indicate that the human nose The triangle indicates that one of hydrogen sulfide and trimethylamine is 1 ppm or less, and the cross indicates that the odor can be recognized by the human nose.

As shown in Tables 3 and 4, the odor of any of the nonwoven fabrics formed as described above sharply decreased within a single hour. In particular, in Example 1, 50 to 91 wt% was obtained as compared with the case where the synthetic suspension A was not diluted.
The odor gas removal performance is higher when the dilution rate is about the same, and in Example 2, the dilution rate is 0 to 95.5.
It can be seen that very good odor gas removal performance is shown over a wide range of wt%.

[Embodiment 3] Next, the above Kyoward 6
The particles (powder, Comparative Example) of Example 00 and the powder (Example 3) obtained by increasing the pH of the synthetic suspension A of Example 1 to agglomerate solids and then drying. Each weight was placed in the above freezer bag, and odor gas (odor gas) was similarly introduced, and the gas removal effect was measured using a gas detector tube. Table 5 shows the results.

[0040]

[Table 5]

As described above, the performance of removing odorous gas is low only with KYOWARD 600 (magnesium silicate), and the performance of removing odorous gas decreases after a certain period of time. The odor gas is rapidly removed with the passage of time, and the removal performance hardly decreases even with the passage of time.

Finally, in order to confirm the duration of the performance of the non-woven fabric having good odor gas removal performance in Examples 1 and 2 (marked with double circles in Tables 3 and 4). A new odor gas was introduced into the freezer bag every hour, and the odor removal performance was repeatedly measured by a gas detector tube until the sixth hour. The results are shown in Table 6 (trimethylamine) and Table 7 (hydrogen sulfide).

[0043]

[Table 6]

[0044]

[Table 7]

As shown in Tables 6 and 7, it can be seen that even if the odor gas is repeatedly removed, the removal performance does not decrease at all, and a removal performance that is almost unchanged from the initial performance can be obtained. When the odor gas was removed six times as described above and the odor gas was removed again for 48 hours, the odor gas removal performance was confirmed to be almost unchanged in this case. .

Furthermore, the synthetic suspension shown in Example 1
B on the surface of an aluminum plate, and
After drying at 0 ° C for 30 minutes, a film with a thickness of 5 to 10 µm
Was formed. Then, the film adhesion method (inorganic antibacterial agent such as silver)
The study group "Self-planning and antibacterial test of silver and other inorganic antibacterial agents
Method)). Yellow as a bacterial species
Using staphylococci in a thermostat at 37 ° C for 24 hours
After culturing, the number of sterilized cells was measured. As a result, the inoculum
2.2 × 10⁶2.6 × 10 ⁴Up to
Reduced, sterilization rate is 99%, with sufficient antibacterial activity
This has been proven.

As described above, in the present embodiment, the catalytic action is activated by carrying the titanium oxide fine particles on magnesium silicate or aluminum silicate, whereby the odor gas removing performance is improved and the odor gas removing performance is improved. The sustainability of the performance is very significantly enhanced. Also,
Since it also has a sufficient antibacterial activity as described above, the solid acid catalyst to which this embodiment is applied is a smoke separation device, an air purifier,
It can be very suitably used as a filter for an air conditioner or the like, or as a purifying agent used with the filter. Further, in the above embodiment, the measurement was performed using trimethylamine as a basic odor gas and hydrogen sulfide as an acidic odor gas, but it was confirmed that both were extremely effective. Thus, it is considered that the solid acid catalyst of the present embodiment can be treated irrespective of the type of odor gas, and it is necessary to change the drug according to the type of odor gas or to use different types of drugs in combination. Because it's gone
It has a very remarkable effect in various uses.

In each of the above embodiments, the synthesis suspension is dried and used in a solid state. However, the solid content in the synthesis suspension is the solid acid catalyst itself, and It is also possible to use it as it is. For example,
It is also possible to use it as a mist spray liquid.

[0049]

As described above, according to the present invention, the base containing transition metal oxide particles is supported on a compound containing at least one structural portion selected from magnesium silicate and aluminum silicate. It is possible to obtain a composition capable of efficiently removing any offensive odors, whether acidic or acidic, and maintaining the removal efficiency for a long period of time. This composition captures and adsorbs malodorous molecules by the adsorption performance that magnesium silicate or aluminum silicate originally has as an adsorbent, and fine particles of transition metal oxide supported in the structure of magnesium silicate or aluminum silicate Acts as a cocatalyst to activate the function as a catalyst,
It is considered that malodorous molecules are chemically substituted by acid points (solid acid) existing on the surface of magnesium silicate or aluminum silicate and decomposed. Therefore, unlike mere absorption involving absorption or chemical reaction, the odor is decomposed and removed by the catalytic action, so that the action can be exhibited efficiently and for a long time even with a limited amount. In addition, a sufficient antibacterial effect can be exhibited by the above structure.

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Claims (10)

[Claims] 1. Magnesium silicate (2MgO.6SiO)
₂ · _{xH 2} O) and aluminum silicate _{(Al 2} O 3 · 9S
A solid acid catalyst comprising a compound containing at least one structural portion selected from iO ₂ .xH ₂ O) and supporting fine particles of a transition metal oxide. 2. The solid acid catalyst according to claim 1, wherein the fine particles have a particle diameter mainly in a range of 0.001 to 1 μm. 3. The solid acid catalyst according to claim 1, further comprising colloidal silica as a binder. 4. One of claims 1 to 3
A gas removing member, wherein the solid acid catalyst described in the above item is held on a substrate. 5. Magnesium silicate (2MgO.6SiO)
₂ · _{xH 2} O) and aluminum silicate _{(Al 2} O 3 · 9S
The iO 2 _· xH 2 _O) a compound containing at least one structural part selected from particles are dispersed in a solvent under acidic under mixed with fine particles of transition metal oxide and the synthetic suspension A method for producing a solid acid catalyst, comprising: 6. The method for producing a solid acid catalyst according to claim 5, wherein the synthetic suspension is dried and solidified. 7. The solid acid catalyst according to claim 5, wherein the synthetic suspension is formed by mixing particles made of the compound into an acidic suspension containing the fine particles. Manufacturing method. 8. One of claims 5 to 7
3. The method for producing a solid acid catalyst according to item 1, wherein the synthetic suspension contains colloidal silica as a binder. 9. Any one of claims 5 to 8
In the item, after dispersing particles comprising the compound in a solvent under acidic conditions, the mixture is diluted with a liquid composed of at least one selected from water and alcohols to form the synthetic suspension. A method for producing a solid acid catalyst. 10. A method for producing a solid acid catalyst according to any one of claims 5 to 9, wherein the synthesis suspension is constituted, and the synthesis suspension is applied to a substrate. And producing the gas removing member.