JP7585689B2 - Novel silicon-containing cyclic tertiary amine, its production method, and its use - Google Patents

Description

The present invention relates to a silicon-containing cyclic tertiary amine having a cyclic tertiary amine in its molecular structure, a method for producing the same, and uses thereof.

Elemental iodine, hydrogen iodide, and organic iodine compounds (hereinafter collectively referred to as "iodine") are widely used in the industrial, agricultural, and medical fields. They are highly volatile and highly reactive, and if they leak or spill, they can cause various types of contamination. In addition, radioactive iodine produced by the nuclear fission of uranium at nuclear power plants poses serious radiation exposure effects on the human body, so particular care must be taken to prevent leaks or spills.

In light of this, in order to prevent contamination damage caused by leakage or outflow of elemental iodine, hydrogen iodide, or organic iodine compounds, these are adsorbed and removed using adsorbents. For this adsorption, highly basic adsorbents are used, and a specific example is a composition in which a cyclic tertiary amine is physically supported on a carrier (a typical example is activated carbon supported with triethylenediamine). It has been reported that activated carbon supported with triethylenediamine shows high selectivity and adsorption amount with respect to the adsorption of elemental iodine, hydrogen iodide, or organic iodine compounds (see, for example, Patent Document 1).

U.S. Pat. No. 4,111,833

Cyclic tertiary amines, such as triethylenediamine, are highly volatile substances, and when these are supported on a carrier, there is an issue that the cyclic tertiary amines, such as triethylenediamine, are released from the carrier during use. There is concern that the release of the cyclic tertiary amines may reduce the adsorption performance of iodine alone, hydrogen iodide, or organic iodine compounds, and that the volatilized cyclic tertiary amines may cause environmental pollution.

The present invention has been made in consideration of the above-mentioned background art, and its object is to provide a cyclic tertiary amine-containing carrier in which elimination of the cyclic tertiary amine from the carrier is suppressed.

The inventors conducted intensive research to solve the above problems and found that a silicon-containing cyclic tertiary amine having a cyclic tertiary amine in its molecular structure functions as a so-called silane coupling agent. Furthermore, they found that a carrier surface-treated with the silicon-containing cyclic tertiary amine, i.e., the cyclic tertiary amine-containing carrier of the present invention, can suppress the elimination of the cyclic tertiary amine from the carrier, which led to the completion of the present invention.

That is, the present invention relates to a silicon-containing cyclic tertiary amine as shown below, a production method thereof, and uses thereof.
[1]
General formula (1)

(In the formula, a and b each independently represent 0 or 1, and the relationship a+b=1 is satisfied; n represents 0, 1, or 2; m represents 1, 2, or 3, and the relationship n+m≦3 is satisfied; and each X independently represents an alkoxy group having 1 to 4 carbon atoms.)
The silicon-containing cyclic tertiary amine is represented by the formula:
[2]
The silicon-containing cyclic tertiary amine according to [1], wherein a is 0 (i.e., b is 1).
[3]
The silicon-containing cyclic tertiary amine according to [1] or [2], wherein each X is independently a methoxy group, an ethoxy group, or an isopropoxy group.
[4]
The silicon-containing cyclic tertiary amine according to any one of [1] to [3], wherein m is 1.
[5]
General formula (2)

(In the formula, each X independently represents an alkoxy group having 1 to 4 carbon atoms; and n represents 0, 1, or 2.)
and a silicon compound represented by the general formula (3)

(In the formula, a and b are each independently 0 or 1, and the relationship a+b=1 is satisfied.)
The method for producing the silicon-containing cyclic tertiary amine according to any one of [1] to [4], characterized by reacting a cyclic tertiary aminoalcohol represented by the formula:
[6]
The method for producing a silicon-containing cyclic tertiary amine according to [5], wherein a is 0.
[7]
A silane coupling agent comprising the silicon-containing cyclic tertiary amine according to any one of [1] to [4].
[8]
A method for producing an adsorbent, comprising mixing at least 100 parts by weight of a carrier with 1 to 80 parts by weight of the silicon-containing cyclic tertiary amine according to any one of [1] to [4] above, and then heating the mixture.
[9]
The method for producing an adsorbent according to [8], wherein the carrier is at least one selected from the group consisting of activated carbon, cellulose, silica, silica gel, alumina, aluminosilicate, zeolite, magnesia, titania, zirconia, ceria, diatomaceous earth, and hydroxyapatite.
[10]
The method for producing an adsorbent according to [8], wherein the carrier is at least one selected from activated carbon, silica gel, and cellulose.
[11]
An adsorbent comprising a carrier containing one or more selected from the group consisting of the silicon-containing cyclic tertiary amine according to any one of [1] to [4], its hydrolysis reaction product, and its condensation reaction product.

By using the silicon-containing cyclic tertiary amine of the present invention, it is possible to provide a cyclic tertiary amine-containing carrier in which the elimination of the cyclic tertiary amine from the carrier is suppressed. This makes it possible to suppress the adverse effects of environmental pollution caused by the elimination of the cyclic tertiary amine.

The present invention is described in detail below.

The present invention relates to the above-mentioned silicon-containing cyclic tertiary amine, a method for producing the silicon-containing cyclic tertiary amine, a silane coupling agent containing the above-mentioned silicon-containing cyclic tertiary amine, and an adsorbent prepared using the above-mentioned silicon-containing cyclic tertiary amine and a method for producing the same.

First, we will explain the silicon-containing cyclic tertiary amine of the present invention.

The silicon-containing cyclic tertiary amine of the present invention is represented by the above general formula (1).

In the above general formula (1), a and b are each independently 0 or 1, and the relationship a+b=1 is satisfied. In terms of ease of obtaining raw materials and excellent properties as a silane coupling agent, it is preferable that a is 0 (i.e., b is 1).

In the above general formula (1), n represents 0, 1, or 2, and m represents 1, 2, or 3, satisfying the relationship n+m≦3. In terms of ease of obtaining raw materials and excellent properties as a silane coupling agent, it is preferable that n is 0 (i.e., m is 1, 2, or 3).

In the above general formula (1), each X is independently an alkoxy group having 1 to 4 carbon atoms. Examples of the alkoxy group include, but are not limited to, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a cyclopropoxy group, a butoxy group, a 1-methylpropoxy group (s-butoxy group), a 2-methylpropoxy group (i-butoxy group), a 1,1-dimethylpropoxy group (t-butoxy group), a cyclobutoxy group, and a cyclopropylmethoxy group. Among these, in terms of the ease of availability of raw materials, each X is preferably independently a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a 2-methylpropoxy group, a 1-methylpropoxy group, or a 1,1-dimethylpropoxy group, and more preferably a methoxy group, an ethoxy group, or an isopropoxy group.

The silicon-containing cyclic tertiary amine (1) of the present invention has optical isomers, and the silicon-containing cyclic tertiary amine (1) of the present invention may be any of the optical isomers or may be a mixture of two or more optical isomers.

Specific examples of the silicon-containing cyclic tertiary amine represented by general formula (1) include the following compounds (exemplary compounds 1-1 to 2-30), but the present invention is not limited to these. In the formula, Me represents a methyl group, Et represents an ethyl group, Pr represents a propyl group, i-Pr represents an isopropyl group, and Bu represents a butyl group.

Among these, in terms of easy availability of raw materials, low production costs, and high iodine adsorption capacity, exemplary compounds 1-1, 1-2, 1-3, 1-16, 1-17, 1-18, 1-26, 1-27, 1-28, 2-1, 2-2, 2-3, 2-16, 2-17, 2-18, 2-26, 2-27, and 2-28 are preferred, 1-1, 1-2, 1-16, 1-17, 1-26, and 1-27 are more preferred, and 1-1, 1-16, and 1-26 are particularly preferred.

Next, we will explain the method for producing the silicon-containing cyclic tertiary amine represented by the above general formula (1) and its uses.

The silicon-containing cyclic tertiary amine represented by the above general formula (1) can be produced by reacting a cyclic tertiary amino alcohol represented by the following general formula (3) with an isocyanate compound represented by the following general formula (2) (hereinafter also referred to as "Step 1"). Furthermore, by treating a carrier with the silicon-containing cyclic tertiary amine produced above as a silane coupling agent, an adsorbent (cyclic tertiary amine-containing carrier) with excellent iodine adsorption performance can be produced (hereinafter also referred to as "Step 2").

(In the formula, a and b each independently represent 0 or 1, and the relationship a+b=1 is satisfied; n represents 0, 1, or 2; m represents 1, 2, or 3, and the relationship n+m≦3 is satisfied; and each X independently represents an alkoxy group having 1 to 4 carbon atoms.)
First, step 1 will be described. The silicon-containing cyclic tertiary amine represented by the above general formula (1) can be prepared by reacting a silicon-containing cyclic tertiary amine represented by the following general formula (2):

(In the formula, each X independently represents an alkoxy group having 1 to 4 carbon atoms; and n represents 0, 1, or 2.)
and a silicon compound represented by the following general formula (3):

(In the formula, a and b are each independently 0 or 1, and the relationship a+b=1 is satisfied.)
It can be prepared by reacting with a cyclic tertiary amino alcohol represented by the formula:

The definitions and preferred ranges of X, a, b, n, and m shown in the general formulas (2) and (3) are the same as those in the general formula (1).

Examples of the cyclic tertiary amino alcohol (3) that can be used in step 1 include 2-(hydroxymethyl)-1,4-diazabicyclo[2.2.2]octane and 1,5-diazabicyclo[3.2.2]nonan-3-ol.

The cyclic tertiary amino alcohol (3) may be a commercially available product or may be synthesized by a known method, and is not particularly limited. In the case of synthesis, it can be produced by the method described in, for example, Khimiya Geterotsiklicheskikh Soedinenil, Vol. 10, p. 1404 (1980) or WO 95/18104. It can also be produced by intramolecular cyclization of an ethylene oxide adduct of hydroxyalkyl piperazines derived by the method described in Journal of Medicinal Chemistry (1993), Vol. 36, p. 2075-2083 or the method described in JP-A 2010-120887. Furthermore, it can be produced by, for example, the method described in JP-A 2010-37325, i.e., by a cyclization reaction of dihydroxyalkyl piperazines.

In the production of the silicon-containing cyclic tertiary amine (1) of the present invention, if necessary, other amines may be mixed and used in combination with the above-mentioned cyclic tertiary amino alcohol (3). Examples of other amines include aliphatic amines, aromatic amines, and/or cyclic tertiary amines other than those mentioned above.

The silicon compound represented by the above general formula (2) may be a commercially available product, or may be synthesized by a known method.

There are no particular limitations on the purity of the raw materials (2) and (3) used in step 1 above, but considering the ease of purification in the purification step, a purity of 95% or more is preferred, and 98% or more is particularly preferred.

In the above step 1, a catalyst may be used if necessary. There are no particular limitations on the catalyst, so long as it accelerates the reaction between the silicate ester and the cyclic tertiary amino alcohol. Examples of the catalyst include titanium alkoxides such as titanium tetra n-butoxide, acidic catalysts such as heteropolyacids, hydrochloric acid, p-toluenesulfonic acid, trichloroacetic acid, trifluoroacetic acid, trifluoromethanesulfonic acid, and acidic ion exchange resins, basic catalysts such as piperidine, alkali metal alkoxides, alkali metal hydroxides, alkaline earth oxides, quaternary ammonium salt compounds, quaternary phosphonium salt compounds, and basic ion exchange resins, halogen compounds such as iodine and iodine bromide, and metallic sodium.

These catalysts can be used alone or in a mixture of two or more kinds. The form of the catalyst is not particularly limited, but may be, for example, liquid, powder, or granular. The method of preparation of the catalyst is also not particularly limited, and may be a commercially available catalyst or one synthesized by a known method, and is not particularly limited.

In the above-mentioned step 1, a solvent may be used when carrying out the reaction. The solvent is not particularly limited, but for example, tetrahydrofuran, dioxane, acetonitrile, dimethoxyethane, dimethylformamide, dimethylsulfoxide, dichloromethane, chloroform, benzene, toluene, xylene, etc. can be used. In addition, these solvents can be used alone or in combination of two or more kinds as necessary.

In step 1 above, the reaction temperature is not particularly limited, but is usually in the range of 10°C to 200°C. The preferred reaction temperature is 20°C to 80°C. A reaction temperature within the above range is preferred in that the reaction rate is practical and there is little deterioration of the equipment due to decomposition or corrosion of the product, etc.

In step 1, the reaction pressure is not particularly limited, but is usually in the range of normal pressure to 1 MPa. If it is within the above range, it is preferable in that the reaction rate is practical and there is little deterioration of the equipment due to decomposition of the product, corrosion, etc.

In the above step 1, the raw material concentration is not particularly limited, but in order to increase production efficiency, it is preferable to set the concentration of cyclic tertiary amino alcohol (3) to 10% by weight or more.

In step 1, the mixing ratio of the silicon compound represented by general formula (2) and the cyclic tertiary amino alcohol represented by general formula (3) is not particularly limited, but in order to increase production efficiency, a ratio of 0.25 to 4 times by mole of the cyclic tertiary amino alcohol represented by general formula (3) per mole of the silicon compound represented by general formula (2) is preferred, a ratio of 0.5 to 2 times by mole of the cyclic tertiary amino alcohol represented by general formula (3) per mole of the silicon compound represented by general formula (2) is more preferred, and a ratio of 0.75 to 1.5 times by mole of the cyclic tertiary amino alcohol represented by general formula (3) per mole of the silicon compound represented by general formula (2) is more preferred.

The reaction method in step 1 can be any of a flow reaction, batch reaction, and semi-batch reaction, and is not particularly limited. However, a flow reaction is preferred from the viewpoint of productivity.

In the above step 1, the reaction atmosphere is not particularly limited, and may be, for example, in air or in an inert atmosphere. In order to minimize decomposition of the raw materials or the silicon-containing cyclic tertiary amine due to moisture in the air, it is preferable to carry out the reaction in an inert atmosphere.

The silicon-containing cyclic tertiary amine of the present invention produced by the above step 1 can be used as a silane coupling agent based on the reactivity of its silanol residues. That is, the silanol group portion of the silicon-containing cyclic tertiary amine of the present invention can undergo a hydrolysis reaction and react with a separate reactive group such as a hydroxyl group or a sulfide group (e.g., a reactive group possessed by a carrier) to form a new covalent bond. In addition, the silanol groups of the silicon-containing cyclic tertiary amine of the present invention can undergo a condensation reaction with each other to form a polycondensate of the silicon-containing cyclic tertiary amine.

Next, we will explain step 2, which is a method for producing a cyclic tertiary amine-containing carrier of the present invention. Step 2 is characterized in that at least 100 parts by weight of the carrier and 1 to 80 parts by weight of a silicon-containing cyclic tertiary amine represented by the above general formula (1) are mixed, and then heated.

The carrier used in the above manufacturing method is not particularly limited, but may be at least one selected from the group consisting of activated carbon, cellulose, silica, silica gel, alumina, aluminosilicate, zeolite, magnesia, titania, zirconia, ceria, diatomaceous earth, and hydroxyapatite. Of these, at least one selected from the group consisting of activated carbon, silica, and cellulose is preferred. When two or more types are used, the types and ratios can be changed as desired.

The carrier may be one that is publicly known or one that is synthesized by a method publicly known in the art. The raw materials, synthesis method, surface area, pore size, etc. of the carrier are not particularly limited. The shape of the carrier is not particularly limited, but examples include spherical (spherical particles, etc.), granular, fibrous, granular, monolithic column, hollow fiber, membrane (flat membrane, etc.). Of these, spherical, membrane, granular, or fibrous shapes are preferred in terms of ease of availability, ease of handling, and processability.

When using particulate carriers, the particle size is usually in the range of 1 μm to 10 mm, but from the viewpoints of appropriate pressure loss as an adsorbent and ease of manufacture, the range of 5 μm to 1 mm is preferable, and the average pore size is usually in the range of 1 nm to 100 μm, with the range of 1 nm to 100 nm being preferable from the viewpoint of adsorption performance.

The cyclic tertiary amine-containing carrier of the present invention is characterized by the fact that the amount of material released from the carrier is minimal. For example, when 1 g of the cyclic tertiary amine-containing carrier is immersed in 10 g of water for 1 hour, the amount of elution is preferably 5% by weight or less, more preferably 3% by weight or less, relative to the cyclic tertiary amine-containing carrier. In addition, the amount of volatile organic matter after 1 hour at 60°C is preferably 5 μg/g or less, more preferably 3 μg/g or less.

By carrying out the operation of step 2 above, the silicon-containing cyclic tertiary amine represented by general formula (1) undergoes polycondensation through the silanol group or forms a covalent bond with the above-mentioned carrier. This produces a carrier containing a cyclic tertiary amine, i.e., an adsorbent in which a modified product of the silicon-containing cyclic tertiary amine represented by general formula (1) is immobilized on the carrier.

When performing the operation of mixing the carrier and the amine, and the operation of heating the resulting mixture, the operations can be performed in the presence of water or a solvent. Note that it is preferable to have water present in the above operations, since it can promote the hydrolysis reaction and condensation reaction of the silicon-containing cyclic tertiary amine. In this case, the amount of water used is preferably 1 to 1000 times by mole, and more preferably 2 to 100 times by mole, per mole of the silicon-containing cyclic tertiary amine, from the viewpoint of promoting the reaction.

The solvent is not particularly limited, but examples thereof include methanol, ethanol, propanol, isopropanol, butanol, ethylene glycol, diethylene glycol, glycerin, tetrahydrofuran, dioxane, acetonitrile, methoxyethanol, dimethoxyethane, dimethylformamide, dimethylsulfoxide, benzene, toluene, and xylene. These solvents may be used alone or in combination of two or more types as required. Among these, inexpensive methanol or ethanol are preferred.

The method for mixing the carrier and the amine is not particularly limited, but examples thereof include a method in which the amine is simply dropped, sprayed, suspended, or circulated directly onto the carrier, or a method in which the amine is dissolved and diluted in the solvent beforehand, and then dropped, sprayed, suspended, or circulated onto the carrier. The mixture obtained by mixing in this manner can also be further physically mixed using a mortar, a stirring device, a grinding device, or the like.

In the manufacturing method of the present invention, the heating temperature is preferably 50°C to 200°C, and more preferably 60°C to 150°C, in order to promote the reaction of the amine.

The reaction pressure during heating is preferably in the range of normal pressure to 1 MPa in order to promote the reaction of the amine.

The atmosphere during the heating is not particularly limited, and examples include air or an inert atmosphere.

The manufacturing method of the present invention is characterized in that 1 to 80 parts by weight of the silicon-containing cyclic tertiary amine represented by the above general formula (1) is mixed with 100 parts by weight of the carrier. From the viewpoint of the performance and cost of the adsorbent, however, it is preferable to mix the amount of the amine in the range of 10 to 50 parts by weight, and it is more preferable to mix the amount of the amine in the range of 10 to 30 parts by weight.

In the manufacturing method of the present invention, it is preferable that the carrier used is not surface-treated to prevent a decrease in the processing efficiency, but there is no problem if the carrier is surface-treated in advance as long as the reactive active sites remain. Conversely, there is no problem if the carrier is activated in advance to increase the processing density.

The adsorbent (cyclic tertiary amine-containing carrier) of the present invention produced in this manner has the effect of suppressing the adverse effects of environmental pollution caused by the elimination of cyclic tertiary amines from the carrier, since the elimination of cyclic tertiary amines is very small. In addition, the adsorbent of the present invention has the effect of efficiently adsorbing and removing iodine (including organic iodine compounds), but can also be suitably used for adsorbing and removing chemical substances such as elemental halogens, hydrohalic acids, and acidic substances.

The adsorbent obtained by the above manufacturing method is an adsorbent consisting of a carrier containing a product produced by the hydrolysis reaction and/or condensation reaction of the silicon-containing cyclic tertiary amine. The adsorbent of the present invention thus obtained can be used as an adsorbent for various chemical substances. For example, if the cyclic tertiary amine-containing carrier of the present invention is filled in a filter, it can be used as a chemical substance adsorption filter. Specifically, it can be suitably used as an adsorption filter for volatile iodine.

The adsorbent of the present invention obtained in this manner is characterized by suppressing the detachment of cyclic tertiary amines from the carrier, and can therefore also be used as a filter for gas masks or a tap water purification filter.

The present invention will be described in more detail with reference to the following examples, but the present invention should not be construed as being limited to these.

The synthesized compounds were analyzed using a Hitachi High-Tech Science high-performance liquid chromatograph Chromaster 5610 mass detector.

The content of cyclic tertiary amine contained in the cyclic tertiary amine-containing carrier was calculated assuming that the weight increase from the carrier was due to the hydrolysis of the silicon-containing cyclic tertiary amine resulting in the production of silsesquioxane (a polymer in which all alkoxy groups have been eliminated and which has a 1.5 molar ratio of oxygen to silicon atoms).

Synthesis Example 1 (Preparation of triethylenediamine-supported material) 3.5 g (31.2 mmol) of triethylenediamine (manufactured by Tosoh Corporation), 10.0 g of silica gel (Wakogel (registered trademark) C-300, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and 30 g of methanol were added to a 50 mL eggplant flask and stirred at room temperature for 10 minutes. Stirring was then stopped, and the solvent was removed using a rotary evaporator while heating to 40°C. In this way, 13.5 g of white powder of triethylenediamine-supported silica (triethylenediamine content 2311 mmol/kg, 25.9% by weight) was obtained.

Example 1 (Preparation of Example Compound 1-2)

A stirrer, 44.0 g (211.4 mmol) of tetraethoxysilane (Tokyo Chemical Industry Co., Ltd.), and 30.1 g (211.4 mmol) of 1,4-diazabicyclo[2.2.2]octane-2-methanol were placed in a 200 mL three-neck flask, and the reaction atmosphere was replaced with nitrogen by passing nitrogen gas through it for 10 minutes. A reflux tube and a 90° bent connecting tube were connected to the flask, so that ethanol generated in the reaction could be collected outside the system through the bent connecting tube. The flask was heated at 100°C for two days, and the reaction was stopped when it was confirmed that no ethanol was generated from the reaction solution, and 53.6 g of a brown liquid was obtained. Mass spectrometry (PCI-MS) confirmed that the obtained brown liquid was the target exemplary compound 1-2.

Mass spectrometry (PCI-MS): 305 (M+1)
Example 2 (Preparation of a cyclic tertiary amine-containing carrier)
In a 50 mL eggplant flask, 2.4 g (7.9 mmol) of the exemplary compound 1-2 prepared in Example 1 and 5.0 g of silica gel (Wakogel C-300, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were added, and the mixture was stirred at room temperature for 3 h. The mixture was stirred for 10 days. Then, the solvent was removed by a rotary evaporator, and the mixture was heated at 140° C. for 10 hours in a nitrogen atmosphere using a muffle furnace. This operation resulted in the reaction of Exemplified Compound 1-2 on the silica gel. The resulting white powder was filtered on a Buchner funnel lined with filter paper, washed with methanol, and then heated in a muffle furnace under a nitrogen atmosphere. and dried overnight at 120° C. In this manner, 6.0 g of a white powder of cyclic tertiary amine-containing silica 1 (content of silicon-containing cyclic tertiary amine: 1,303 mmol/kg, 28.7% by weight) was obtained. .

Example 3 (Preparation of Example Compound 1-1)

In Example 1, 32.2 g (211.4 mmol) of tetramethoxysilane (Tokyo Chemical Industry Co., Ltd.) was used instead of 44.0 g (211.4 mmol) of tetraethoxysilane, and methanol was collected as a by-product liquid. The same procedure as in Example 1 was carried out to obtain 52.7 g of exemplary compound 1-1 as a brown liquid. Mass spectrometry (PCI-MS) confirmed that the obtained brown liquid was the desired exemplary compound 1-1.

Mass spectrometry (PCI-MS): 263 (M+1)
Example 4 (Preparation of cyclic tertiary amine-containing carrier)
The same procedure as in Example 2 was repeated except that 2.0 g (7.6 mmol) of the exemplary compound 1-1 prepared in Example 3 was used instead of 2.4 g (7.9 mmol) of the exemplary compound 1-2. The same procedure as in Example 2 was carried out to obtain 5.9 g of a white powder of cyclic tertiary amine-containing silica 2 (cyclic tertiary amine content: 1,303 mmol/kg, 28.7 wt %).

Example 5 (Evaluation of the release properties of cyclic tertiary amine from the support)
15 mg of the cyclic tertiary amine-containing silica 1 obtained in Example 2 was placed in a glass tube and heated at 30°C for 1 hour, and the volatilized components were adsorbed with a TENAX (registered trademark) adsorbent. The adsorbed components were then heated to be desorbed again, and analyzed by GC-MS to quantify the amount of volatilized cyclic tertiary amine. As a result of the measurement, the cyclic tertiary amine was not detected (<1 μg/g-sample, equivalent to <1 mmol/kg-sample in terms of triethylenediamine). The results are shown in Table 1.

Example 6 (Evaluation of the release properties of cyclic tertiary amine from the support)
15 mg of the cyclic tertiary amine-containing silica 1 obtained in Example 2 was placed in a glass tube and heated at 60°C for 1 hour, and the volatilized components were adsorbed with a TENAX (registered trademark) adsorbent. The adsorbed components were then heated to be desorbed again, and analyzed by GC-MS to quantify the amount of volatilized cyclic tertiary amine. As a result of the measurement, the cyclic tertiary amine was not detected (<1 μg/g-sample, equivalent to <1 mmol/kg-sample in terms of triethylenediamine). The results are shown in Table 1.

Example 7 (Evaluation of the release properties of cyclic tertiary amine from the support)
15 mg of the cyclic tertiary amine-containing silica 1 obtained in Example 2 was placed in a glass tube and heated at 90°C for 1 hour, and the volatilized components were adsorbed with a TENAX (registered trademark) adsorbent. The adsorbed components were then heated to be desorbed again, and analyzed by GC-MS to quantify the amount of volatilized cyclic tertiary amine. As a result of the measurement, the cyclic tertiary amine was not detected (<1 μg/g-sample, equivalent to <1 mmol/kg-sample in terms of triethylenediamine). The results are shown in Table 1.

Compared with Comparative Examples 1 to 3 below, it became clear that the cyclic tertiary amine-containing carrier of the present invention effectively fixes the cyclic tertiary amine to the carrier, suppressing the volatilization of the cyclic tertiary amine.

Example 8 (Evaluation of the release properties of cyclic tertiary amine from the support)
15 mg of the cyclic tertiary amine-containing silica 2 obtained in Example 4 was placed in a glass tube and heated at 30°C for 1 hour, and the volatilized components were adsorbed with a TENAX (registered trademark) adsorbent. The adsorbed components were then heated to be desorbed again, and analyzed by GC-MS to quantify the amount of volatilized cyclic tertiary amine. As a result of the measurement, the cyclic tertiary amine was not detected (<1 μg/g-sample, equivalent to <1 mmol/kg-sample in terms of triethylenediamine). The results are shown in Table 1.

Example 9 (Evaluation of the release of cyclic tertiary amine from the support)
15 mg of the cyclic tertiary amine-containing silica 2 obtained in Example 4 was placed in a glass tube and heated at 60°C for 1 hour, and the volatilized components were adsorbed with a TENAX (registered trademark) adsorbent. The adsorbed components were then heated to be desorbed again, and analyzed by GC-MS to quantify the amount of volatilized cyclic tertiary amine. As a result of the measurement, the cyclic tertiary amine was not detected (<1 μg/g-sample, equivalent to <1 mmol/kg-sample in terms of triethylenediamine). The results are shown in Table 1.

Example 10 (Evaluation of the release of cyclic tertiary amine from the support)
15 mg of the cyclic tertiary amine-containing silica 2 obtained in Example 4 was placed in a glass tube and heated at 90°C for 1 hour, and the volatilized components were adsorbed with a TENAX (registered trademark) adsorbent. The adsorbed components were then heated to be desorbed again, and analyzed by GC-MS to quantify the amount of volatilized cyclic tertiary amine. As a result of the measurement, the cyclic tertiary amine was not detected (<1 μg/g-sample, equivalent to <1 mmol/kg-sample in terms of triethylenediamine). The results are shown in Table 1.

Comparative Example 1 (Evaluation of Removal Property of Cyclic Tertiary Amine from Carrier)
15 mg of triethylenediamine-supported silica obtained in Synthesis Example 1 (amount of triethylenediamine supported: 2311 mmol/kg) was placed in a glass tube and heated at 30° C. for 1 hour, and the volatilized components were adsorbed with a TENAX (registered trademark) adsorbent. The adsorbed components were then heated to be desorbed again, and analyzed by GC-MS to quantify the amount of triethylenediamine. As a result of the measurement, an amount of 449 μg/g-sample (equivalent to 4 mmol/kg-sample) was detected as triethylenediamine. The results are shown in Table 1.

Comparative Example 2 (Evaluation of Removal Property of Cyclic Tertiary Amine from Carrier)
15 mg of triethylenediamine-supported silica obtained in Synthesis Example 1 (amount of triethylenediamine supported: 2311 mmol/kg) was placed in a glass tube and heated at 60° C. for 1 hour, and the volatilized components were adsorbed with a TENAX (registered trademark) adsorbent. The adsorbed components were then heated to be desorbed again, and analyzed by GC-MS to quantify the amount of triethylenediamine. As a result of the measurement, an amount of 188,409 μg/g-sample (equivalent to 1,680 mmol/kg-sample) was detected as triethylenediamine. The results are shown in Table 1.

Comparative Example 3 (Evaluation of Removal Property of Cyclic Tertiary Amine from Carrier)
15 mg of triethylenediamine-supported silica obtained in Synthesis Example 1 (amount of triethylenediamine supported: 2311 mmol/kg) was placed in a glass tube and heated at 60° C. for 1 hour, and the volatilized components were adsorbed with a TENAX (registered trademark) adsorbent. The adsorbed components were then heated to be desorbed again, and analyzed by GC-MS to quantify the amount of triethylenediamine. As a result of the measurement, an amount of 253679 μg/g-sample (equivalent to 2262 mmol/kg-sample) was detected as triethylenediamine. The results are shown in Table 1.

This demonstrated that when cyclic tertiary amines are physically adsorbed onto a carrier, they easily volatilize.

The results in Table 1 reveal that the cyclic tertiary amine-containing carrier of the present invention effectively fixes the cyclic tertiary amine to the carrier, suppressing the volatilization of the cyclic tertiary amine.

Example 11 (Evaluation of methyl iodide adsorption performance)
A 10 L Tedlar bag A was filled with 5 L of nitrogen gas and 100 μL of methyl iodide (iodomethane, manufactured by Tokyo Chemical Industry Co., Ltd.) and heated at 60° C. for 3 minutes to completely vaporize the methyl iodide (7,160 ppm of methyl iodide gas). 5 L of the above methyl iodide gas was passed through a Teflon (registered trademark) tube filled with 0.50 g of cyclic tertiary amine-containing silica 1 (described in Example 2) at a flow rate of 0.1 L/min, and the exhaust gas was collected in another Tedlar bag B. The methyl iodide concentrations of the sample gas before and after the passage were analyzed by gas chromatography, and the methyl iodide adsorption rate (%) was evaluated from the change in methyl iodide concentration. The results are shown in Table 2.

Example 12 (Evaluation of methyl iodide adsorption performance)
The same procedure as in Example 11 was carried out, except that 0.50 g of cyclic tertiary amine-containing silica 2 (described in Example 4) was used instead of 0.50 g of cyclic tertiary amine-containing silica 1 in Example 11, to evaluate the methyl iodide adsorption performance. The results are shown in Table 2.

Comparative Example 4
The same procedure as in Example 11 was carried out, except that 0.50 g of silica gel (Wakogel (registered trademark) C-300, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) was used instead of 0.50 g of the cyclic tertiary amine-containing silica 1 in Example 11, to evaluate the methyl iodide adsorption performance. The results are shown in Table 2.

The results in Table 2 make it clear that the tertiary amine-containing carrier of the present invention is useful for adsorbing and removing methyl iodide.

The cyclic tertiary amine-containing carrier of the present invention is useful in adsorbing and removing chemical substances such as iodine, cyanogen chloride, and nitrogen dioxide, similar to conventional carriers that physically support cyclic tertiary amines (e.g., activated carbon containing triethylenediamine).

Claims (11)

General formula (1)
(In the formula, a and b each independently represent 0 or 1, and the relationship a+b=1 is satisfied; n represents 0, 1, or 2; m represents 1, 2, or 3, and the relationship n+m≦3 is satisfied; and each X independently represents an alkoxy group having 1 to 4 carbon atoms.)
The silicon-containing cyclic tertiary amine is represented by the formula: The silicon-containing cyclic tertiary amine according to claim 1, in which a is 0 (i.e., b is 1). The silicon-containing cyclic tertiary amine according to claim 1 or 2, wherein each X is independently a methoxy group, an ethoxy group, or an isopropoxy group. The silicon-containing cyclic tertiary amine according to any one of claims 1 to 3, wherein m is 1. General formula (2)
(In the formula, each X independently represents an alkoxy group having 1 to 4 carbon atoms; and n represents 0, 1, or 2.)
and a silicon compound represented by the general formula (3)
(In the formula, a and b are each independently 0 or 1, and the relationship of a+b=1 is satisfied.)
5. The method for producing the silicon-containing cyclic tertiary amine according to claim 1, comprising reacting a cyclic tertiary aminoalcohol represented by the formula: The method for producing a silicon-containing cyclic tertiary amine according to claim 5, wherein a is 0. A silane coupling agent comprising the silicon-containing cyclic tertiary amine according to any one of claims 1 to 4. A method for producing an adsorbent, comprising mixing at least 100 parts by weight of a carrier with 1 to 80 parts by weight of a silicon-containing cyclic tertiary amine according to any one of claims 1 to 4, and then heating the mixture. The method for producing an adsorbent according to claim 8, characterized in that the carrier is at least one selected from the group consisting of activated carbon, cellulose, silica, silica gel, alumina, aluminosilicate, zeolite, magnesia, titania, zirconia, ceria, diatomaceous earth, and hydroxyapatite. The method for producing an adsorbent according to claim 8, characterized in that the carrier is at least one selected from activated carbon, silica gel, and cellulose. An adsorbent comprising a carrier containing one or more selected from the group consisting of the silicon-containing cyclic tertiary amine according to any one of claims 1 to 4, its hydrolysis reaction product, and its condensation reaction product.