JP2014047301A - Polymer gel and production method thereof, and fluoride ion scavenger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polymer gel containing a 1,8-naphthalene diurea unit, a production method thereof and a fluoride ion scavenger.SOLUTION: The polymer gel containing a 1,8-naphthalene diurea unit is synthesized by a radical crosslinking polymerization using a monomer containing polymerizable functional groups at both terminals of a 1,8-naphthalene diurea unit, a hydrophilic monomer and a cross-linkable monomer as raw materials to obtain a scavenger specifically recognizing and absorbing fluoride ions and exhibiting luminous characteristics.

Description

  The present invention relates to a polymer gel containing 1,8-naphthalenediurea units, a method for producing the same, and a fluoride ion scavenger.

  Materials containing fluorine atoms are used in a wide range of fields due to their excellent performance. Fluorine resin, fluorine coating, and fluorine rubber are materials that represent fluorine-based materials, and have performances that surpass conventional materials by containing fluorine atoms. For example, the melting point of P (registered trademark) is 80 ° C. higher than that of PE, and heat resistance, chemical resistance, and ferroelectricity are properties that only P (registered trademark) has.

  In addition, fluororesins are classified as super engineering plastics because of their particularly high performance among engineering plastics. Excellent thermal properties, physical properties, mechanical properties, and electrical properties are characteristic of fluororesins, and PTFE (polytetrafluoroethylene) is well known. PTFE has chemical resistance, heat resistance, surface characteristics, and electrical insulation, and is widely used as pipes, bearings, frying pans, electronic jars, and the like. Moreover, the moldability which is the only fault of PTFE is solved by the development of a homopolymer such as polyvinylidene fluoride and the development of a copolymer such as a copolymer FEP with 6-fluoropropylene (HFP). Today, blended polymer, block copolymer, and polymer alloy technologies make it an indispensable material in fields such as semiconductors and electrical / electronic components.

  However, the current situation is that enormous funds are required for the development and production of fluorine-based materials. The first reason is that the fluorine source required for production is expensive. For example, (diethylamino) sulfur trifluoride (DAST) used when fluorinating alcohol is 12000 yen for 5 g, and a normal fluorinating agent is about 10,000 yen for 5 g. This is by no means related to the scarcity of fluorine. For this reason, since the fluorine-based material that has permeated society is a material that does not work as a substitute, immediate response is required.

  On the other hand, wastewater and hot spring water at glass factories and medical sites contain a large amount of fluoride ions, and many of them have been washed away into rivers. According to the Water Pollution Control Law amended in 2006, fluorine-containing solutions are also regarded as harmful substances, and fluorine 8 mg / L (15 mg / L for sea discharge) and a drainage upper limit are set. In response to these changes in the environment, companies have surpassed the urgent need by adding calcium ions. However, when it calculates from the solubility product value of the calcium fluoride to produce | generate, it becomes difficult to satisfy | fill a reference value.

  In any case, at present, fluoride ions, which are a useful resource, are treated just like garbage and are not reused. In addition, no measures have been taken regarding hot spring water. We must urgently consider solutions for the recycling of valuable resources and the reduction of harmful substances flowing into rivers.

  In general, with the rapid development of chemistry in recent years, there have been many reports on the synthesis of molecules that enable ion collection or ion recognition. Most of the research is aimed at collecting cations such as alkali metal ions and radioactive metal ions typified by crown ether.

  On the other hand, examples of research on the collection of anions include azacrown ethers and porphyrins having an NH functional part.

  What is common to these compounds is that N—H hydrogen has a δ + property (acidity) suitable for collecting anions. However, there are few reports on the collection of anions compared to the research examples on the collection of cations. This is because the properties of anions make it difficult to synthesize host molecules. The characteristic is that the electrostatic interaction with other chemical species is weak. This is because the ionic radius is larger than that of an isoelectronic cation, and the charge in the radius is smaller than that of the cation. Moreover, for the same reason, the polarity is higher than that of the cation, and it is difficult to construct a site having a binding force for recognizing the anion.

  From such a general situation, and because it has unique properties among halide ions, molecular design for collecting fluoride ions has not been easy. In fact, there have been few research examples so far. There are only a few examples of fluoride ion collection that have been reported so far.

  For example, one example is the recognition of fluoride ions based on boron atoms. It has been reported that phosphonioborin can efficiently recognize fluoride ions in water (Non-patent Document 1).

  In addition, it has been clarified that 1,8-naphthalene diurea, a low molecular weight compound having a benzene ring at both ends, collects fluoride ions in acetonitrile / dimethyl sulfoxide solution and exhibits unique fluorescence behavior (non-patented). Reference 2). This compound is structurally considered to incorporate fluoride ions so as to be surrounded by four NH hydrogen atoms. By incorporating fluoride ions, the diurea structure becomes a structure close to a flat surface, and the expansion of the π-conjugated system occurs.

  Further, this compound does not exhibit such fluorescence characteristics at all for chloride ions, bromide ions, and iodide ions having the same ionic radius as the elements of the same group. From this, it can be said that selective recognition of fluoride ions has been achieved.

Chemistry Letters, 36, 976-977 (2007). Journal of American Chemical Society, 125, 12376-12377 (2003).

  However, the organic molecules reported in Non-Patent Documents 1 and 2 both recognize fluoride ions and both can visually recognize fluoride ions, that is, they can be used as chemical sensors. It is not actually used for collecting fluoride ions. Since these are small molecules, it is difficult to develop them for practical use from contaminated water.

  The present invention has an object to provide a new technical means that can practically collect fluoride ions from contaminated water or the like from the background described above.

  The present invention is derived from focusing on polymer gels by the inventors. That is, the polymer gel is a substance that does not dissolve because the polymer chain has a network structure, absorbs the solvent and swells to a certain volume. Polymer gels exist widely and are expected in recent years as water-retaining agents for konjac, tofu, water-absorbing diapers, and desert greening. It is also often used as a carrier in ion exchange resins and GPC (gel permeation chromatography). Then, the present inventor examined incorporating the 1,8-naphthalene diurea structure into the polymer gel based on the molecular design of Non-Patent Document 2. This is because the development of utilization as a scavenger for fluoride ions in organic solvents and further in water can be greatly expected. This is because, in particular, it can be sufficiently used for collecting fluoride ions from a dilute solution after most of the fluoride ions are removed by precipitation by the conventional calcium carbonate precipitation method. At the same time, it can be expected that the fluoride ion concentration of the waste liquid containing the fluorine source is lowered to a concentration that does not conflict with the water pollution prevention method.

  The present invention has been invented as a result of the above studies, and has remarkable features that cannot be expected or predicted from conventional knowledge.

  That is, the present invention provides a polymer gel having a 1,8-naphthalene diurea structure, a production method thereof, and a fluoride ion scavenger.

  First, the following formula (1)

(In the formula, A, B and C each represents a molecular unit bonded in a carbon chain by polymerization, A represents a molecular unit having a 1,8-naphthalene diurea structure, and B represents a crosslinkable molecular unit. C represents a hydrophilic molecular unit, and the order of arrangement of each molecular unit is not limited.)
It is a polymer gel characterized by having the repeating unit structure represented by these.

  The molecular unit A is represented by the following formula (2)

(Wherein R ¹ and R ² are the same or different and each represents a hydrogen atom or a hydrocarbon group, R ³ represents a hydrogen atom, a hydrocarbon group or an alkoxy group, and X ¹ and X ² are The same or different represents an oxygen atom or NH, and Y ¹ and Y ² represent the same or different alkylene or oligooxyalkylene group, and n represents an integer of 1 to 6.)
It preferably has a 1,8-naphthalene diurea structure represented by

  The molecular unit B is represented by the following formula (3)

(In the formula, R ⁴ represents a hydrogen atom or a hydrocarbon group, Z ¹ and Z ² represent the same or different oxygen atom or NH, and Y ³ represents an alkylene or oligooxyalkylene group)
It is preferable that it is a crosslinkable molecular unit represented by these.

  The molecular unit C is represented by the following formula (4)

(Wherein R ⁵ represents a hydrogen atom or a hydrocarbon group, and Q represents a hydrophilic group)
It is preferable that it is a hydrophilic molecular unit represented by these.

  Here, the hydrophilic group Q has the following formula (5a) (5b)

(W ¹ and W ² in the formula represent an oxygen atom or NH, R ⁶ represents an alkylene or oligooxyalkylene group, and R ⁷ represents a hydrocarbon group.)
It is preferably considered that any one of

  The present invention also provides a method for producing the polymer gel, wherein the monomer has a 1,8-naphthalene diurea structure with a polymerizable carbon chain, a crosslinkable monomer having a polymerizable carbon chain, and a hydrophilic polymer having a polymerizable carbon chain. Provided is a method for producing a polymer gel, which comprises radical crosslinking copolymerization of a functional monomer.

  In this production method, it is preferable to carry out radical crosslinking copolymerization in an organic solvent in the presence of a radical initiator.

  And this invention provides the fluoride ion scavenger characterized by containing the said polymer gel as an active ingredient.

  With this scavenger, the polymer gel is dispersed in the liquid, and fluoride ions can be collected with a selectivity 10 times higher than that of chloride ions, bromide ions, and iodide ions. Furthermore, it is preferably considered that the fluorescent property is exhibited only at the time of collecting fluoride ions.

  The present invention also provides a method for collecting fluoride ions, characterized in that fluoride ions are collected using the fluoride ion collector.

Furthermore, in the present invention, useful as a monomer for the synthesis of the polymer gel,
Formula (6)

(Wherein R ¹ and R ² are the same or different and each represents a hydrogen atom or a hydrocarbon group, R ³ represents a hydrogen atom, a hydrocarbon group or an alkoxy group, and X ¹ and X ² are The same or different represents an oxygen atom or NH, and Y ¹ and Y ² represent the same or different alkylene or oligooxyalkylene group, and n represents an integer of 1 to 6.)
A novel 1,8-naphthalenediurea compound is also provided.

  Also provided are a chemical sensor for detecting fluoride ions using this compound and a method for detecting fluoride ions.

  According to the present invention, a polymer gel excellent in the ability to collect fluoride ions is provided. In this polymer gel, for example, the collection ability can be controlled and improved by introducing hydrophilic molecular units at an appropriate ratio. There have been no examples of efficient fluoride ion scavengers from dilute solutions so far, but the fluorine source can be efficiently recovered by using the polymer gel of the present invention and the existing calcium precipitation method together. If possible, it is possible to reduce both the manufacturing cost of the fluorine-based material by reusing the recovered fluorine source and the reduction of environmental pollution due to the fluorine source.

(A) No ion addition, (b) Fluoride ion addition, (c) Chloride ion addition, (d) Bromide ion addition in 1,8-naphthalene diurea monomer compound in acetonitrile-dimethyl sulfoxide (DMSO) solution FIG. 5 shows each fluorescence spectrum in (b), and it can be seen that a long wavelength shift of the maximum fluorescence wavelength is observed due to the coordination of fluoride ions, and blue fluorescence is generated. FIG. 2 is a diagram showing fluorescence spectra before and after the formation of fluoride complexes of two types of polymer gels having different monomer mixing ratios of the present invention, both of (b) and (d) after addition of a fluorine source having a long maximum fluorescence wavelength. A wavelength shift is observed, and it can be seen that blue fluorescence occurs.

  The present invention is described in detail below.

  The polymer gel of the present invention has a structure generally represented by the formula (1). It consists of a molecular unit A having a 1,8-naphthalene diurea structure, a crosslinkable molecular unit B, and a hydrophilic molecular unit C.

These molecular units (A), (B), and (C) are bonded in a carbon chain by polymerization regardless of the order of arrangement. Among these, it can be said that the molecular unit (A) having a 1,8-naphthalene diurea structure has a naphthalene diurea unit as a side chain portion with respect to a so-called main chain structure bonded in a carbon chain shape. Needless to say, the naphthalene diurea unit as the side chain moiety may have various molecular structures.
The crosslinkable molecular unit (B) and the hydrophobic molecular unit (C) may be various as long as the main chain structure bonded in a carbon chain is formed as described above.
Conventionally, no polymer gel in which such molecular units (A), (B), and (C) are bonded in a carbon chain by polymerization is known, and this polymer gel has an excellent ability to collect fluoride ions. It is not known that they are doing.

  The molecular unit A is represented by the formula (2), the crosslinkable molecular unit B is represented by the formula (3), the hydrophilic molecular unit C is represented by the formula (4), and Is preferably represented by the formulas (5a) and (5b).

  In these formulas, those having 1 to 10 carbon atoms are preferably considered for hydrocarbon groups and alkoxy groups, and those having about 2 to 30 carbon atoms are preferred for alkylene and oligooxyalkylene groups. The oligooxyalkylene group means a group in which a plurality of units of-(alkylene chain -O)-are repeated.

In general, for the repetition coefficients a, b, and c of the molecular units A, B, and C in the formula (1), an integer of 1 to 100 is a standard,
b / a = 5-100
c / a = 5-50
Can be taken into account.

  The polymer gel of the present invention has a 1,8-naphthalene diurea unit corresponding to the molecular unit A as a core, a monomer having a polymerizable reactive group introduced at both ends thereof, and a crosslinkable monomer corresponding to the molecular unit B, And it can manufacture by mixing the hydrophilic monomer corresponding to the molecular unit C, for example, performing radical crosslinking polymerization in presence of a radical initiator. In particular, for example, a monomer having a 1,8-naphthalene diurea unit as a core and a methacrylic acid ester moiety introduced at both ends is used as a crosslinking agent such as ethylene dimethacrylate (EDMA), and hydrophilic such as hydroxyethyl methacrylate (HEMA) having hydrophilicity. By using a functional monomer, the adsorption ability of fluoride ions can be further improved. When the constituent components are changed, the adsorption ability of fluoride ions can be changed. This is based on the high hydration characteristic peculiar to fluoride ions, and can be said to be a novel collection behavior.

  A monomer having a 1,8-naphthalene diurea unit used as a raw material in the present invention as a core and a polymerizable reactive group introduced at both ends thereof is not particularly limited, but the monomer represented by the above (6) is preferably used. it can.

In particular, R ¹ and R ² are preferably a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and R ³ is independently a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a C 1 to 10 carbon atom. X ¹ and X ² are each an oxygen atom or NH, and Y ¹ and Y ² are a divalent hydrocarbon group having 2 to 30 carbon atoms or an oligooxyethylene group (CH ₂ CH ₂ It is preferable that several O ⁻ are connected.

  Examples of the hydrocarbon group include linear alkyl groups such as a methyl group and an ethyl group, and cyclic alkyl groups such as cyclohexyl.

Among these, R ¹ and R ² are most preferable from the viewpoint of supplying methacrylic acid whose methyl group is a raw material, and hydrogen atoms can also be preferably used from the viewpoint of supplying acrylic acid which is also a raw material.

X ¹ and X ² are preferably oxygen atoms, that is, methacrylic acid esters or acrylic acid esters.

Y ¹ and Y ² may be different divalent groups, but are preferably the same. Y ¹ and Y ² linking the polymerizable reactive group and the 1,8-naphthalene diurea unit that is the collection site are preferably groups having 2 to 30 carbon atoms, but the hydrophilic polymer has a partial structure of polyethylene glycol. Certain oligo (oxyethylene) groups are more preferred.

  A monomer having a 1,8-naphthalene diurea unit used as a raw material in the present invention and having a polymerizable reactive group introduced at both ends thereof contains a urea structure at the 1,8-position of the naphthalene ring. Fluoride ions can be efficiently introduced into the center of a square having apexes of hydrogen atoms having moderate acidity (δ +) on the four NH groups contained in the 1,8-naphthalene diurea structure. Moreover, since the molecular structure is changed by the introduction, the 1,8-naphthalene diurea unit containing fluoride ions becomes more planar and the conjugate length is extended, so that its optical properties are greatly changed and absorbed. Long wavelength shifts in wavelength and fluorescence wavelength are seen. Therefore, the presence or absence of fluoride ion adsorption can be confirmed by visual and spectroscopic techniques.

  A feature of the present invention is that adsorption is hardly caused by chloride ions, bromide ions, and iodide ions that are group element ions other than fluoride ions, and only fluoride ions can be selectively collected. This is considered to be due to the fact that the ion adsorption site matches the size of the fluoride ion having a small ionic radius and the electronegativity of the fluorine atom is large.

  The hydrophilic monomer is preferably a monomer corresponding to the formulas (5a) and (5b) in the above formula (4). More specifically, for example, the following formula (7)

Any of those represented by can be preferably used. In order to improve the adsorption ability of fluoride ions having hydration properties, a hydrophilic monomer is used, but is not limited thereto.

  As the crosslinkable monomer, the molecular unit B, preferably corresponding to the formula (3), is represented by the following formula (8):

Can be used.

  In addition, the coefficients m, p, q, s, and r in the above formulas each independently represent an integer of 2 to 100.

R ⁴ is preferably a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and examples of such a hydrocarbon group include a saturated aliphatic hydrocarbon group and an alicyclic hydrocarbon group. Among these, a methyl group is most preferable from the viewpoint of supply of methacrylic acid as a raw material, and a hydrogen atom can also be preferably used from the viewpoint of supply of acrylic acid as a raw material.

Z ¹ and Z ² are preferably oxygen atoms, that is, methacrylic acid esters or acrylic acid esters.

Y ³ connects the polymerizable reactive groups to each other, but is not particularly limited, but an ethylene group having 2 carbon atoms is preferably used.

  In the present invention, the charging ratio of the monomer having 1,8-naphthalene diurea unit, the hydrophilic monomer and the crosslinkable monomer is not particularly limited, but is preferably in the range of 1: 1 to 200: 1 to 20.

  The radical initiator may be a general-purpose reagent, and examples thereof include azo compounds such as azobisisobutylnitrile (AIBN), peroxides such as benzoyl peroxide (BPO), and the like. % By weight. If the amount is too little or too much, the degree of polymerization is difficult to increase.

  For example, an aprotic organic solvent can be used as the polymerization solvent. Since it is desirable to completely dissolve the monomer having a 1,8-naphthalenediurea unit at the time of polymerization, an organic solvent having excellent solubility is preferable. Among them, N, N-dimethylformamide (DMF) and N-methylpyrrolidinone are preferable. (NMP) is more preferred. Moreover, you may use 2 or more types together, not single. In addition, since oxygen may inhibit polymerization, it is preferable to perform a deaeration operation such as nitrogen bubbling before use.

  Although the compounding quantity of an organic solvent is not specifically limited, 10-100 mass parts is preferable with respect to 1 mass part of monomer which has a 1,8- naphthalene diurea unit of a raw material.

  In the production of a polymer gel, a raw material monomer having an 1,8-naphthalene diurea unit and an organic solvent are placed in a container and dissolved under heating, and then a hydrophilic monomer, a crosslinkable monomer, and a radical initiator are further added. After nitrogen substitution, the reaction can be carried out with stirring under heating. The preferable reaction temperature for gel preparation varies depending on the monomers used, particularly monomers having 1,8-naphthalene diurea units, but if the reaction temperature is too low, the reaction rate may decrease and polymerization may stop. On the other hand, if the reaction temperature is too high, impurities are contained in the polymer gel due to side reactions such as chain transfer reaction and decomposition of the organic solvent. In general, the polymerization reaction is preferably performed at 50 to 120 ° C., and particularly when N, N-dimethylformamide (DMF) is used as the organic solvent, it is preferably performed at 90 ° C. or less. Although reaction time is not specifically limited, For example, it is 5 minutes-5 hours. The reaction may be stopped when an insoluble component is generated in the container by visual observation.

  After completion of the reaction, the solid is taken out from the container, finely ground in a mortar, collected by suction, washed successively with chloroform and distilled water, and dried to obtain the intended polymer gel.

This polymer gel can efficiently collect fluoride ions in an organic solvent containing a trace amount of fluoride ions (10 ⁻² to 10 ⁻⁵ mol / L) or from water. The fact that fluoride ions are collected is manifested as fluorescence characteristics. The collection performance of fluoride ions is at least 10 times that of chloride ions, bromide ions, and iodide ions.

  Thus, it is a polymer gel that has sufficient selectivity and is not visible because it is visible. By combining the calcium carbonate precipitation method and the hydroxyapatite method conventionally used for fluoride ion recovery, it is possible to collect fluoride ions in a wide range of concentrations from high to low. In the case of high-concentration solution, first add calcium carbonate, precipitate and separate as calcium fluoride (fluorite), and then add this polymer gel to the solution with reduced concentration to make the fluoride ion contained in a trace amount more efficient. Can be collected.

  The collection efficiency tends to be improved by increasing the mixing ratio of the hydrophilic monomer.

  In addition, the monomer having 1,8-naphthalene diurea unit used in the present invention is useful as a chemical sensor using a novel low molecular weight compound, that is, a chemical sensor for detecting fluoride ions, as the formula (6). It is.

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

In the following examples, JHOL JNM-ECX400 (400 MHz) was used for ¹ H-NMR measurement. Me ₄ Si (δ = 0.00) was used as an internal standard.

¹³ C-NMR measurement was performed using JNM-JNM-ECX400 (100 MHz). DMSO-d ₆ (δ = 39.5) was used as an internal standard.

  IR measurement used FTIR-4100 made from JEOL.

The UV-vis measurement was performed in water, and a two-sided transparent cell (10 × 10 mm) was used. A JASCO V-630 spectrophotometer was used as a measuring instrument. For the fluorescence measurement, a transparent transparent cell (10 × 10 mm) was used in a mixed solvent of acetonitrile and dimethyl sulfoxide (volume ratio 9: 1). A JASCO FP-6500 spectrophotometer was used as a measuring instrument.
<Example 1>
According to the following reaction formula, a monomer having 1,8-diaminonaphthalene diurea unit was obtained by the reaction of 1,8-diaminonaphthalene and 2-isocyanatoethyl methacrylate.

That is, first, a three-way cock and a septum were attached to a 30 mL two-necked flask and dried under reduced pressure. DMF (5 mL) was added to 1,8-naphthalenediamine (0.238 g, 1.5 mmol) and heated to dissolve completely. Next, 2-isocyanatoethyl methacrylate (0.424 mL, 3 mmol) was slowly added under ice cooling. A nitrogen balloon was attached and the reaction was carried out at 80 ° C. for 5 hours after nitrogen substitution. After completion of the reaction, the reaction solution was dropped into a beaker containing ethanol. The solid was collected, washed with ethanol, and vacuum dried to obtain the desired product in a yield of 78% (0.547 g). The structural analysis was performed by ¹ H-NMR spectrum, ¹³ C-NMR spectrum and IR spectrum.

  The results are shown in Table 1.

  For the obtained 1,8-naphthalene diurea compound, a THF solution of tetrabutylammonium halide (TBAX) was added to an acetonitrile-DMSO (v / v = 9/1) solution in order to verify the coordination properties of fluoride ions. Coordination for each of fluoride ion (F), chloride ion (Cl), and bromide ion (Br) was confirmed.

FIG. 1 shows the result. It was confirmed that only when TBAF, that is, fluoride ions were added, the maximum fluorescence wavelength was shifted by a long wavelength with respect to the excitation light of 310 nm, and blue fluorescence was emitted. It can be seen that the coordinated ^- selectively F.
<Example 2>
According to the following formula, a monomer having 1,8-diaminonaphthalene diurea unit was obtained by reaction of 1,8-diaminonaphthalene and 2-isocyanatoethoxyethyl methacrylate.

That is, first, a three-way cock and a septum were attached to a 30 mL two-necked flask and dried under reduced pressure. DMF (10 mL) was added to 1,8-naphthalenediamine (0.474 g, 3 mmol) and completely dissolved. Next, 2-isocyanatoethoxyethyl methacrylate (1.194 g, 6 mmol) was slowly added under ice cooling. A nitrogen balloon was attached and the reaction was carried out at 80 ° C. for 30 minutes after nitrogen substitution. After completion of the reaction, the reaction solution was dropped into a beaker containing ethanol. The solid was collected by filtration, washed with ethanol, and vacuum dried to obtain the desired product in 92% yield (1.529 g). The structural analysis was performed by ¹ H-NMR spectrum, ¹³ C-NMR spectrum and IR spectrum.

  The results are shown in Table 2.

<Example 3>
By performing radical crosslinking polymerization according to the following formula using the monomer having 1,8-diaminonaphthalene diurea unit synthesized in Example 1, 2-hydroxyethyl methacrylate (HEMA) and ethylene dimethacrylate (EDMA) as a crosslinking agent as raw materials. A polymer gel was prepared.

  That is, first, a reflux tube, a three-way cock and a septum were attached to a 30 mL two-necked flask and dried under reduced pressure. DMF (2 mL) was then added and nitrogen bubbling was performed for 15 minutes. The monomer (93.6 mg, 0.2 mmol) having 1,8-diaminonaphthalene diurea units synthesized in Example 1 was added and completely dissolved. Next, HEMA (0.048 mL, 0.4 mmol), EDMA (0.8 mmol or 1.2 mmol), and azobisisobutyronitrile (AIBN) as a radical initiator were added at 10 wt% of the total amount of monomers. A nitrogen balloon was attached and the reaction was carried out at 80 ° C. for 30 minutes after nitrogen substitution. After completion of the reaction, the obtained solid was pulverized in a mortar and washed with chloroform at the time of suction filtration to obtain a gel (GelA) in the case of EDMA 0.8 mmol and a gel (GelB) in the case of 1.2 mmol. Each was obtained quantitatively. For purification, the polymer gel was pulverized in a mortar and washed with distilled water.

About the obtained GelA and GelB, it carried out similarly to the case of Example 1, and evaluated the complex formation of the fluoride. FIG. 2 shows the result. Blue fluorescence emission due to the long wavelength shift of the maximum fluorescence wavelength was clearly confirmed with respect to the excitation light of 310 nm. This confirmed the complex formation with F ⁻ .
<Example 4>
A radical having a 1,8-diaminonaphthalene diurea unit containing a lot of oxyethylene chains synthesized in Example 2, 2-hydroxyethyl methacrylate (HEMA) and ethylene dimethacrylate (EDMA) as a crosslinking agent as raw materials according to the following formula A polymer gel was prepared by cross-linking polymerization.

That is, first, a reflux tube, a three-way cock and a septum were attached to a 30 mL two-necked flask and dried under reduced pressure. DMF (2 mL) was then added and nitrogen bubbling was performed for 15 minutes. The monomer (112 mg, 0.2 mmol) having 1,8-diaminonaphthalene diurea unit synthesized in Example 2 was added and heated to be completely dissolved. Next, HEMA (0.145 to 0.581 mL, 1.2 to 4.8 mmol), EDMA (0.225 mL, 1.2 mmol), and azobisisobutyronitrile (AIBN) which is a radical initiator are used as monomers. 10 wt% of the total amount was added. A nitrogen balloon was attached and the reaction was carried out at 80 ° C. for 30 minutes after nitrogen substitution. After completion of the reaction, the obtained solid was pulverized in a mortar and washed with chloroform at the time of suction filtration to obtain a polymer gel quantitatively. For purification, the polymer gel was pulverized in a mortar and washed with distilled water.
<Example 5>
The fluoride ion adsorption experiment in a polymer gel acetonitrile-dimethyl sulfoxide (MeCN-DMSO, v / v = 9/1) solution was performed as follows.

  First, 40 mg of polymer gel finely pulverized using a mortar was added to the sample bottle. Next, 0.164 mL of a THF solution of 1 mol / L tetrabutylammonium fluoride (TBAF) was added to a 100 mL volumetric flask, and then a MeCN-DMSO mixed solution was added to make the total volume 100 mL. 10 mL was taken out from this solution, added to the sample bottle containing the polymer gel, and stirred at room temperature for 3 hours to adsorb fluoride ions to the polymer gel. Only acetonitrile was distilled off from the filtrate after removing the polymer gel from the dispersion by an evaporator and vacuum drying (20 mmHg). 100 mL of distilled water was added to the subsequent dimethyl sulfoxide solution. This solution was weighed with a 1 mL syringe and added to an empty 10 mL volumetric flask. To this volumetric flask, 1 mL of 5% Alfusson aqueous solution, 4 mL of acetone and distilled water were added to make a total volume of 10 mL, and left for 3 hours. After the obtained solution was transferred to a quartz cell, UV-visible absorption spectrum measurement was performed, and the absorbance at 620 nm was measured. The concentration of TBAF solution prepared separately, that is, the molar concentration (x) and absorbance (y The concentration of fluoride ions contained in the solution was determined from a calibration curve representing the relationship of (1)) = 186.5x + 0.5166. Finally, the amount of fluoride ion adsorbed by the polymer gel was estimated from the difference and volume from the fluoride ion concentration before adsorption.

  The amount of monomer and EDMA synthesized in Example 2 was fixed at 0.2 mmol and 1.2 mmol, respectively, and the amount of HEMA was changed to 1.2, 2.4, 3.6, and 4.8 mmol. The above operation was performed using a polymer gel. Table 3 shows the measurement results.

It can be seen that the amount of fluoride ion adsorbed depends on the content of HEMA used as the hydrophilic comonomer, and increases as the proportion of HEMA increases (Run 5>4>3> 2). As shown in Table 3, such a tendency is observed for the polymer gel having the same weight. Since the weight is the same, the amount of adsorption of the fluoride ion adsorption site is large even though Run5 has the smallest ratio. This is thought to be due to the fact that the introduction ratio of HEMA increases, so that a more hydrophilic environment is built in the polymer gel, and fluoride ions having extremely large interaction with water are more likely to approach the adsorption site. . In Run 5, which had the highest fluoride ion adsorption ability, the fluoride ions equivalent to 8.06 × 10 ⁻³ mol / L were adsorbed from a solution of 1.80 × 10 ⁻³ mol / L. It can be seen that 45% is adsorbed to the stock solution.

Materials containing fluorine atoms are used in a wide range of fields due to their excellent performance. Fluorine resin, fluorine coating, and fluorine rubber are materials that represent fluorine-based materials, and have performances that surpass conventional materials by containing fluorine atoms. For example, the melting point of P VDF (registered trademark) is 80 ° C. higher than that of PE, and heat resistance, chemical resistance, and ferroelectricity are properties that only P VDF (registered trademark) has.

Claims (15)

The following formula (1)
(In the formula, A, B and C each represents a molecular unit bonded in a carbon chain by polymerization, A represents a molecular unit having a 1,8-naphthalene diurea structure, and B represents a crosslinkable molecular unit. C represents a hydrophilic molecular unit, and the order of arrangement of each molecular unit is not limited.)
A polymer gel having a repeating unit structure represented by: The molecular unit A is represented by the following formula (2)
(Wherein R ¹ and R ² are the same or different and each represents a hydrogen atom or a hydrocarbon group, R ³ represents a hydrogen atom, a hydrocarbon group or an alkoxy group, and X ¹ and X ² are The same or different represents an oxygen atom or NH, and Y ¹ and Y ² represent the same or different alkylene or oligooxyalkylene group, and n represents an integer of 1 to 6.)
The polymer gel according to claim 1, which has a 1,8-naphthalene diurea structure represented by: The molecular unit B is represented by the following formula (3)
(In the formula, R ⁴ represents a hydrogen atom or a hydrocarbon group, Z ¹ and Z ² represent the same or different oxygen atom or NH, and Y ³ represents an alkylene or oligooxyalkylene group)
The polymer gel according to claim 1, wherein the polymer gel is a crosslinkable molecular unit represented by the formula: The molecular unit C is represented by the following formula (4)
(Wherein R ⁵ represents a hydrogen atom or a hydrocarbon group, and Q represents a hydrophilic group)
The polymer gel according to claim 1, wherein the polymer gel is a hydrophilic molecular unit represented by the formula: The hydrophilic group Q has the following formulas (5a) (5b)
(W ¹ and W ² in the formula represent an oxygen atom or NH, R ⁶ represents an alkylene or oligooxyalkylene group, and R ⁷ represents a hydrocarbon group.)
The polymer gel according to claim 4, wherein the polymer gel is any one of the following:   A method for producing a polymer gel according to any one of claims 1 to 5, wherein the monomer has a 1,8-naphthalene diurea structure together with a polymerizable carbon chain, a crosslinkable monomer having a polymerizable carbon chain, and polymerization. A method for producing a polymer gel, comprising subjecting a hydrophilic monomer having a functional carbon chain to radical crosslinking copolymerization.   The method for producing a polymer gel according to claim 6, wherein radical crosslinking copolymerization is performed in an organic solvent in the presence of a radical initiator.   A fluoride ion scavenger comprising the polymer gel according to any one of claims 1 to 5 as an active ingredient.   The fluoride ion scavenger according to claim 8, wherein the polymer gel is dispersed in a liquid.   The fluoride ion scavenger according to claim 8 or 9, which can collect fluoride ions with a selectivity 10 times or more than chloride ions, bromide ions, and iodide ions.   The fluoride ion scavenger according to any one of claims 8 to 10, which exhibits a fluorescence characteristic only at the time of fluoride ion trapping.   The fluoride ion collection method characterized by collecting fluoride ion using the fluoride ion collection agent as described in any one of Claims 8-11. Formula (6)
(Wherein R ¹ and R ² are the same or different and each represents a hydrogen atom or a hydrocarbon group, R ³ represents a hydrogen atom, a hydrocarbon group or an alkoxy group, and X ¹ and X ² are The same or different represents an oxygen atom or NH, and Y ¹ and Y ² represent the same or different alkylene or oligooxyalkylene group, and n represents an integer of 1 to 6.)
A 1,8-naphthalene diurea compound represented by the formula:   A chemical sensor comprising the 1,8-naphthalene diurea compound according to claim 13 as a fluoride ion detection component.   A method for detecting fluoride ions, comprising detecting fluoride ions by using the chemical sensor according to claim 14.