JP5158586B2 - Black solid sulfonated substance, production method thereof, ion exchanger using the same, electrolyte membrane, catalyst, membrane electrode assembly, fuel cell - Google Patents

Description

The present invention relates to a black solid sulfonated substance, a method for producing the same, an ion exchanger using the same, an electrolyte membrane, a catalyst, a membrane electrode assembly, and a fuel cell, and more specifically, a proton conducting membrane, a catalyst, Ion exchanger, membrane electrode assembly, ion exchange capacity that can be used for fuel cells, catalytic performance, black solid sulfonated substance with high proton conductivity and excellent heat resistance, its production method and ion exchanger using the same, The present invention relates to an electrolyte membrane, a catalyst, a membrane electrode assembly, and a fuel cell.

  In recent years, fuel cells having high energy efficiency and low environmental impact have attracted attention. A fuel cell is one that converts chemical energy of fuel into electrical energy by electrochemically oxidizing fuel such as hydrogen or methanol using oxygen or air.

  Such fuel cells are classified into a solid polymer type, a phosphoric acid type, a molten carbonate type, a solid oxide type, an alkaline type, and the like depending on the type of electrolyte used. Among these, a polymer electrolyte fuel cell using a cation exchange membrane as an electrolyte can be operated at a high current because the internal resistance in the fuel cell can be reduced by thinning the electrolyte membrane to be used, and can be miniaturized. Because of these advantages, research on solid polymer types has become active.

The electrolyte membrane used in the polymer electrolyte fuel cell is required to have high proton conductivity with respect to protons involved in the electrode reaction of the fuel cell. As such proton conductive materials, sulfonic acid group-containing fluororesins such as trade name Nafion (manufactured by DuPont) are known. However, these polymer electrolyte materials have a problem that they are fluorine resins having a high environmental load, and the synthesis route is complicated and very expensive.
In addition, since the sulfonic acid group-containing fluororesin has a low glass transition temperature and low heat resistance, the operating temperature is lowered to about 80 ° C. to 100 ° C., resulting in poor efficiency. Currently, development of a new proton conductive material to replace the sulfonic acid group-containing fluororesin is underway, but it has not yet been put into practical use.

  In recent years, environmental problems have been highlighted, and high-efficiency catalyst development has attracted attention. It is expected that the environmental load can be reduced by reducing the energy used during the reaction. As an example of this, the sulfonic acid group-containing fluororesin described above may be used as a catalyst, but is not so often used because it is expensive.

  Furthermore, commercialized ion exchange resins are also demanded of materials having low heat resistance and high heat resistance.

  A sulfonated compound is optimal as a material used in applications such as fuel cells, catalysts, and ion exchange resins. This is because the sulfonic acid group exhibits proton conduction performance, catalyst performance, and ion exchange performance.

Among the sulfonated compounds, there are several examples in which an aromatic ring having an alkyl group is sulfonated. Backer et al. Reacted mesitylene with chlorosulfonic acid in 1935 to obtain 1,3,5-trimethylbenzene-2,4-disulfonyl chloride (Non-patent Document 1).
Kilpatrick et al. Investigated the reaction rate between mesitylene and sulfuric acid in 1961 (Non-patent Document 2).
There are few reports on the sulfonation of hexamethylbenzene. Certaintain et al. Reported in 1988 that the methyl group moved by reacting with sulfuric acid at room temperature (Non-patent Document 3).
As far as we know, there has been no report of the reaction of chlorosulfonic acid with hexamethylbenzene.

Next, the deterioration of the solid polymer electrolyte membrane due to OH radicals will be described.
As shown in FIG. 1 and FIG. 2, a single cell 11 of a conventional polymer electrolyte fuel cell (PEFC) has a solid polymer electrolyte membrane 1 (perfluorocarbon sulfonic acid membrane) as a carbon black particle and a catalytic substance [ An air electrode side catalyst layer 2 of a cell sandwiched between an air electrode side catalyst layer 2 supporting mainly platinum (Pt) or a platinum group metal (Ru, Rh, Pd, Os, Ir)] and a fuel electrode side catalyst layer 3; There is provided a membrane electrode assembly 12 in which the fuel electrode side catalyst layer 3 is sandwiched between the air electrode side gas diffusion layer 4 and the fuel electrode side gas diffusion layer 5 to form the air electrode 6 and the fuel electrode 7.
Then, a gas flow path 8 for reaction gas flow is provided facing the air electrode side gas diffusion layer 4 and the fuel electrode side gas diffusion layer 5, and a cooling water flow path 9 for cooling water flow is provided on the opposing main surface. A single cell 11 is formed by being sandwiched by a pair of separators 10 made of a gas-impermeable material.
An oxidant such as air is supplied to the air electrode 6, and a fuel gas containing hydrogen or an organic fuel is supplied to the fuel electrode 7 to generate electricity.

That is, when the reaction gas is supplied to each of the fuel electrode 7 and the air electrode 6, the following electrochemical reaction occurs and DC power is generated.
The fuel electrode side: 2H2 → 4H ^{+ +} 4e ^-
The air electrode ^{side: O2 + 4H + + 4e -} → 2H2 O
An oxidation reaction of hydrogen molecules (H2) occurs on the fuel electrode side, and a reduction reaction of oxygen molecules (O2) occurs on the air electrode side, so that H ⁺ ions generated on the fuel electrode 7 side are solid polymer electrolyte membrane 1. The inside moves toward the air electrode 6 side, and e ⁻ (electrons) moves to the air electrode 6 side through an external load.
On the other hand, on the air electrode 6 side, oxygen contained in the oxidant gas reacts with H ⁺ ions and e ⁻ that have moved from the fuel electrode 7 side to generate water. Thus, the polymer electrolyte fuel cell generates a direct current from hydrogen and oxygen to generate water.

However, the reduction reaction on the air electrode side (4-electron reduction of oxygen molecules (O2)) is difficult, and the following electrochemical reaction (2-electron reduction of oxygen molecules (O2)) occurs as a side reaction on the air electrode side. H2 O2 is generated. If Fe (II) or the like is present as an impurity, H2 O2 is decomposed by the catalytic action, and OH. (OH radical) and OH ^- are generated.

The air electrode ^{side: O2 + 2H + + 2e -} → H2 O2
H2 O2 + Fe (II) → OH · + OH ⁻ + Fe (III)
The generated OH · (OH radical) has a large oxidizing power and oxidizes and decomposes and degrades the solid polymer electrolyte membrane 1.
Receil des Travaux Chimiquest des Pays-Bas et de la Belgium (1935), 54 544-51 Journal of Physical Chemistry (1961), 65 530-2. Canadian Journal of chemistry, 66 (1), 162-7; 1988

The first object of the present invention is to provide a low-cost black solid sulfonated material having high proton conductivity, excellent heat resistance, and excellent ion exchange capacity, catalyst performance, and OH radical resistance. Yes,
The second object of the present invention is to provide a method for easily producing such a black solid sulfonated material at low cost,
Still another object of the present invention is to provide a proton conductive membrane, a catalyst, an ion exchanger, a membrane electrode assembly, and a fuel cell, which are excellent in OH radical resistance using such a black solid sulfonated substance. is there.

  The present invention is not the result of advancing research on an aromatic ring having an alkyl group in order to solve the above-mentioned problems. Hexamethylbenzene, which is considered to have low reactivity as a reaction solvent when happening to sulfonate another compound. As a result of diligent investigation as a starting point of research, the above problems were solved even with other aromatic rings having an alkyl group. It has been found that the present invention has excellent performance and can be easily manufactured at low cost, and the present invention has been completed.

That is, the invention of claim 1, wherein the present invention, for the aromatic hydrocarbon compound having an aromatic ring with an alkyl group consisting of mesitylene, or hexamethylbenzene, at a molar ratio of from 100-fold to 0.2-fold A black solid sulfone having an alkyl group and having a sulfonic acid group introduced, obtained by adding a sulfonating agent comprising chlorosulfonic acid and heating at 100 ° C. to 300 ° C. for polyaromatic cyclization It is a chemical substance.

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The invention of claim 2 of the present invention, in a black solid sulfonated material according to claim 1 Symbol placement, a solid ^{13 C-NMR, 125ppm~150ppm, 10ppmm~30ppm} , at least there are three signals 60ppm~90ppm It is characterized by doing.

According to a third aspect of the present invention, in the black solid sulfonated substance according to the first or second aspect , in the infrared spectrum, at least a signal derived from a sulfonic acid group and a signal derived from an alkyl group are present. Features.

According to a fourth aspect of the present invention, in the black solid sulfonated substance according to any one of the first to third aspects, S is present in the range of 2 to 30% by mass by elemental analysis. Features.

The invention according to claim 5 of the present invention is characterized in that, in the black solid sulfonated substance according to any one of claims 1 to 4 , the acid value is 0.1 to 8 meq / g. And

The invention according to claim 6 of the present invention is the method for producing a black solid sulfonated substance according to any one of claims 1 to 5 , wherein the aromatic ring has an alkyl group composed of mesitylene or hexamethylbenzene. for the aromatic hydrocarbon compound having a molar ratio, the sulfonating agent consisting of 100 times the chlorosulfonic acid 0.2 times in addition, the polyaromatic cyclized by heating at 100 ° C. or higher 300 ° C. or less And a method for producing a black solid sulfonated substance, wherein a sulfonic acid group is introduced.

The invention according to claim 7 of the present invention is an ion exchanger characterized in that the black solid sulfonated substance according to any one of claims 1 to 5 is used.

The invention according to claim 8 of the present invention is an electrolyte membrane using the black solid sulfonated substance according to any one of claims 1 to 5 .

The invention according to claim 9 of the present invention is an acid catalyst characterized in that the black solid sulfonated substance according to any one of claims 1 to 5 is used.

A tenth aspect of the present invention is a membrane electrode assembly using the electrolyte membrane according to the eighth aspect.

An eleventh aspect of the present invention is a fuel cell using the electrolyte membrane according to the eighth aspect.

Black solid sulfonated material according to claim 1 of the present invention, for the aromatic hydrocarbon compound having an aromatic ring with an alkyl group consisting of mesitylene, or hexamethylbenzene, at a molar ratio of from 0.2 times A black color having an alkyl group and a sulfonic acid group introduced, obtained by adding a sulfonating agent composed of 100 times chlorosulfonic acid and heating at 100 ° C. or more and 300 ° C. or less to effect polyaromatic cyclization A solid sulfonated substance,
There is a remarkable effect that proton conductivity is high, heat resistance is excellent, ion exchange capacity, catalyst performance, OH radical resistance is excellent, and the price is low.
There is a further remarkable effect that the sulfonation efficiency is high and the availability is easy.
If the aromatic ring has 3 to 6 alkyl groups, the target product can be obtained even if the reaction time is short, so that there is a further remarkable effect that energy saving and environmental load are small.
Since there is only one aromatic ring, it is possible to use a commercially available inexpensive material in large quantities, and the black solid sulfonated material obtained has a further remarkable effect of being excellent in each performance.
Mesitylene has a further remarkable effect of being inexpensive, having a high acid value and high sulfonation efficiency.
Hexamethylbenzene is slightly more expensive than mesitylene, but has a further remarkable effect that a black solid sulfonated substance can be obtained in a short reaction.

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According to the second aspect of the present invention, in the black solid sulfonated substance according to the first aspect, at least three signals of 125 ppm to 150 ppm, 10 ppmm to 30 ppm, and 60 ppm to 90 ppm exist in solid state ¹³ C-NMR. It is characterized by this. Such a thing has the further remarkable effect that high activity is high, it is insoluble also in a polar solvent, and it is easy to ensure high performance reliably as an acid catalyst.

According to a third aspect of the present invention, in the black solid sulfonated substance according to the first or second aspect , in the infrared spectrum, at least a signal derived from a sulfonic acid group and a signal derived from an alkyl group are present. It is a characteristic,
There is a further remarkable effect that the sulfonation is reliably performed without leaving the alkyl group, and that each performance is guaranteed to be surely good because the sulfonic acid group is surely present.

According to a fourth aspect of the present invention, in the black solid sulfonated substance according to any one of the first to third aspects, S is present in the range of 2 to 30% by mass by elemental analysis. It is a characteristic,
It can be seen that the higher the S ratio, the more sulfonic acid groups are present. Generally, the more sulfonic acid groups are present, the better the proton conductivity, but if it is too high, the affinity for water increases and the water resistance increases. Decreases, it becomes difficult to use as a fuel cell application. If it is in the range of 2 to 30% by mass, a further remarkable effect is obtained that the proton conductivity is high while maintaining the water resistance.

The invention according to claim 5 of the present invention is characterized in that, in the black solid sulfonated substance according to any one of claims 1 to 4 , the acid value is 0.1 to 8 meq / g. And
It becomes a substance having both water resistance and proton conductivity, and a further remarkable effect that it is easy to use is obtained.

The invention according to claim 6 of the present invention is the method for producing a black solid sulfonated substance according to any one of claims 1 to 5 , wherein the aromatic ring has an alkyl group composed of mesitylene or hexamethylbenzene. for the aromatic hydrocarbon compound having a molar ratio, the sulfonating agent consisting of 100 times the chlorosulfonic acid 0.2 times in addition, the polyaromatic cyclized by heating at 100 ° C. or higher 300 ° C. or less , A method for producing a black solid sulfonated substance characterized by introducing a sulfonic acid group,
The proton conductivity is high, the heat resistance is excellent, the ion exchange capacity, the catalyst performance and the OH radical resistance are excellent, and a black solid sulfonated substance can be easily produced at low cost.

Invention of Claim 7 of this invention is an ion exchanger characterized by using the black solid-state sulfonated substance in any one of Claims 1-5 ,
It has a remarkable effect of high ion exchange performance, excellent heat resistance, and low price.

An invention according to claim 8 of the present invention is an electrolyte membrane using the black solid sulfonated substance according to any one of claims 1 to 5 ,
The proton conductivity is high, the heat resistance is excellent, the OH radical resistance is high, the price is low, and the environmental load is small.

The invention according to claim 9 of the present invention is an acid catalyst characterized by using the black solid sulfonated substance according to any one of claims 1 to 5 ,
It has a remarkable effect of acting as a strong acid, having high catalytic activity, excellent heat resistance, and low cost.

Invention of Claim 10 of this invention is a membrane electrode assembly using the electrolyte membrane of Claim 8 ,
The proton conductivity is high, the heat resistance is excellent, the OH radical resistance is high, the price is low, and the environmental load is small.

Invention of Claim 11 of this invention is a fuel cell using the electrolyte membrane of Claim 8 ,
Since it can operate at a high operating temperature, higher power generation efficiency can be expected, reliability is improved, and the cost is low, and the environmental load is small.

Hereinafter, the present invention will be described in more detail.
The present invention is a sulfonating agent in addition to the aromatic hydrocarbon compound having an aromatic ring with an alkyl group, obtained by heating, a black solid, characterized in that the sulfonic acid groups introduced and having a alkyl group Sulfonated material.

The aromatic hydrocarbon compound having an aromatic ring having an alkyl group used in the present invention refers to a substance in which an alkyl group is directly bonded to an aromatic ring among aromatic hydrocarbon compounds having an aromatic ring.
The aromatic hydrocarbon compound having an aromatic ring only needs to contain a benzene ring, and the benzene ring is one aromatic hydrocarbon or two or more polycyclic aromatic hydrocarbons.
Specific examples of the polycyclic aromatic hydrocarbon compound include aromatic hydrocarbon compounds in which at least two aromatic rings such as naphthalene, pyrene, anthracene, phenanthrene, perylene, and coronene are condensed.
Further, it may be a benzene ring or a heterocyclic ring containing two or more polycyclic aromatic hydrocarbon compounds. Examples of such compounds include compounds having nitrogen-containing heterocycles such as quinoline, phenanthroline, isoquinoline, benzodiazine, indole, indazole and carbazole, oxygen-containing heterocycles such as benzofuran, and sulfur-containing heterocycles such as benzothiophene.

  The number of carbons contained in the alkyl group may be one or more. The alkyl group may be linear or branched.

The larger the number of alkyl groups, the easier it is to obtain a black solid sulfonated material, which is desirable. For example, when toluene is used as a starting material, the reaction progresses slowly, and in the reaction at 150 ° C. for 20 hours, only a black oily substance can be obtained, whereas mesitylene and hexamethylbenzene are sulfonated under these conditions. A black solid sulfonated substance has already precipitated in the reaction system.
As described above, the larger the number of alkyl groups, the better. However, when it is derived from benzene, six of hexamethylbenzene is a logical upper limit. In addition, commercially, the cost is also important, and it is desirable that the selection be made in consideration of these.

Specific examples of the aromatic hydrocarbon compound having an aromatic ring having an alkyl group include, for example, toluene, xylene, mesitylene, tetramethylbenzene, pentamethylbenzene, hexamethylbenzene, methylnaphthalene, dimethylnaphthalene, and trimethyl. Examples include compounds having many aromatic rings such as naphthalene, octamethylnaphthalene, methylanthracene, dimethylanthracene, isopropylbenzene, isobutylbenzene and the like.
In addition, methylquinoline and ethylquinoline which are compounds having nitrogen-containing heterocycle, methylbenzofuran and ethylbenzofuran which are compounds having oxygen-containing heterocycle, methylbenzothiophene and ethyl which are compounds having sulfur-containing heterocycle Examples include benzothiophene.
Among these, mesitylene is inexpensive and the resulting black solid sulfonated material has a high acid value. Hexamethylbenzene is slightly more expensive than mesitylene, but has the effect of obtaining a black solid sulfonated substance in a short reaction, so these mesitylene and hexamethylbenzene are particularly preferably used in the present invention. It is done.

  As the sulfonating agent, generally known ones can be used, including fuming sulfuric acid, sulfuric acid, fluorosulfuric acid, methanesulfonic acid, chlorosulfonic acid, SO2, SO3, NaHSO3, propane sultone, butane sultone, and other sulfonated products. Etc. can be illustrated. Among these, chlorosulfonic acid is easy to purify the obtained organic compound having a sulfonated nitrogen-containing heterocyclic ring.

  The reaction of an aromatic hydrocarbon compound having an aromatic ring having an alkyl group and, for example, chlorosulfonic acid as a sulfonating agent is carried out in a normal reaction vessel. At this time, an air atmosphere, a nitrogen atmosphere, or an argon atmosphere may be used. However, since chlorosulfonic acid reacts with water, it is preferable to prevent water from entering.

  The amount of the aromatic hydrocarbon compound having an aromatic ring having an alkyl group and chlorosulfonic acid is, in terms of molar ratio, 0.2 to 100 times that of chlorosulfonic acid with respect to the aromatic ring having an alkyl group. Double is good. If it is less than 0.2 times, the yield may be significantly reduced. If it exceeds 100 times, a large amount of unreacted chlorosulfonic acid is present, so that neutralization after removal may be difficult.

In the reaction of an aromatic hydrocarbon compound having an aromatic ring having an alkyl group and chlorosulfonic acid as a sulfonating agent, since chlorosulfonic acid itself is a solvent, there is no need for a solvent. When the aromatic hydrocarbon compound having an aromatic ring is difficult to dissolve, the desired product can be obtained satisfactorily if a solvent is present.
As a solvent used for such a purpose, a solvent which dissolves both an aromatic hydrocarbon compound having an aromatic ring having an alkyl group and chlorosulfonic acid as a sulfonating agent and which does not change during the reaction is desirable. As such a thing, a halogenated solvent can be used conveniently. Among them, tetrachloroethane having a high boiling point is particularly good.

The reaction temperature is usually 100 ° C. or higher and 300 ° C. or lower. When the temperature is lower than 100 ° C., the reaction for blackening does not proceed, and what is obtained is a non-black substance, which is easily dissolved in a solvent and cannot be used as a fuel cell or a catalyst.
For example, as described in Non-Patent Document 2, in the case of mesitylene, 1,3,5-trimethylbenzene-2,4-disulfonyl chloride is obtained. If it is 300 ° C. or higher, the boiling point of chlorosulfonic acid will be greatly exceeded, making it difficult to react.

Properties that characterize the black solid sulfonated material thus obtained include the following properties.
(1) It is black visually.
(2) has an acid value,
(3) Three points that are solid at room temperature.
The “black” in the present invention includes all of various blacks such as light black, dark black, light black, dark black, brownish black, brownish black, and reddish black. It doesn't mean a special black color.
Among these, the acid value of (2) can be determined by neutralization titration with an alkaline aqueous solution. The black solid sulfonated material having the above three characteristics has good OH radical resistance essential for fuel cells.
The OH radical resistance can be measured by the Fenton test. The Fenton test is a test in which Fe is used as a catalyst to generate radicals from hydrogen peroxide and the resistance to the radicals is measured.

  The acid value is preferably 0.1 to 8 meq / g. If it is less than 0.1 meq / g, for example, the fuel cell may be inferior in proton conductivity. Moreover, when it exceeds 8 milliequivalent / g, it becomes easy to become water-soluble, for example, there exists a possibility that it may become difficult to use as a fuel cell use.

The black solid sulfonated substance has good performance if signals derived from sulfonic acid groups and alkyl groups are reliably present in the infrared spectrum. Usually, the signal from a sulfonic acid group, can be found in the signal 900cm ^-1 ~1300cm ^-1, whereas signal derived from the alkyl groups can be confirmed by appearing at 2700cm ^-1 ~3100cm ^-1.

The performance of the black solid sulfonated substance is further improved when S is present in the range of 2 to 30% (mass% ) by elemental analysis. Examples of the elemental analyzer include CHNS-932 manufactured by LECO, MT-5 manufactured by YANACO, YS-10 manufactured by YANACO, and VTF-900 manufactured by LECO.

The presence of at least three signals of 125 ppm to 150 ppm derived from an aromatic ring, 10 ppmm to 30 ppm derived from an alkyl group, and 60 ppm to 90 ppm in solid ¹³ C-NMR in a solid black sulfonated material, further increases OH radical resistance and water resistance. Performance such as gender is improved.

The black solid sulfonated material of the present invention can be used, for example, in proton conducting membranes, catalysts, ion exchangers, membrane electrode assemblies, and fuel cells.

The proton conducting membrane referred to in the present invention means a membrane having the ability to conduct protons. The black solid sulfonated substance of the present invention is used as a film by forming it alone or by using a binder resin or the like.
The binder resin to be used may be a resin that does not exhibit proton conductivity, but is more preferably a resin that exhibits proton conductivity by introducing a sulfonic acid group. These resins can be used alone or in admixture of two or more, and the following modified resins (for example, introduction of sulfonic acid groups) and copolymers may be used.
As the resin, epoxy resin, urea resin, silicone resin, propylene resin, phenol resin, xylene resin, melamine resin, polyester resin, alkyd resin, vinylidene resin, furan resin, urethane resin, phenylene ether resin, polycarbonate resin, acrylic resin, Examples include, but are not limited to, amide resins, imide resins, vinyl resins, carboxylic acid resins, fluororesins, nylon resins, styrene resins, and engineering plastics.
Moreover, not only organic resin as mentioned above but organic-inorganic hybrid resin, silicate resin, water glass, various inorganic polymers, etc. can be used.

Since the black solid sulfonated material of the present invention has many strong acid groups and can have a high acid catalyst function, it can be used well as a catalyst.
Although the black solid sulfonated substance of the present invention may be used alone, it can also be used by supporting it on a binder resin or alumina.

The ion exchanger referred to in the present invention is a membrane that selectively transmits ions. Other usable black solid sulfonated material of the present invention alone, the black solid sulfonated material of the present invention is used by担時like the binder resin or alumina.

As an example of a method for producing a membrane electrode assembly using the black solid sulfonated substance of the present invention, the following method can be shown.
First, the black solid sulfonated substance of the present invention is used alone or mixed with the binder resin or the like, then laminated on a support, dried, etc. to form a proton conducting membrane (electrolyte membrane). Further, if necessary, a protective film is laminated thereon and stored. In use, after peeling the support and the protective film, an electrode layer containing a catalyst layer and a gas diffusion layer is formed on both sides of the proton conducting membrane. Thereby, a membrane electrode assembly is obtained.

  A fuel cell can be manufactured by assembling a separator or an auxiliary device (a gas supply device or a cooling device) in a single or stacked manner.

FIG. 1 is a cross-sectional explanatory view of one embodiment of a membrane electrode assembly in which electrode catalyst layers are formed on both surfaces of the proton conducting membrane.
A membrane electrode assembly 12 is formed by joining and laminating the electrode catalyst layers 2 and 3 on both sides of the proton conducting membrane (electrolyte membrane) 1 by a conventional method.

  FIG. 2 is an exploded cross-sectional view showing the configuration of an embodiment of a single cell of a polymer electrolyte fuel cell equipped with the membrane electrode assembly 12. The air electrode side gas diffusion layer 4 having a structure in which a mixture of carbon black and polytetrafluoroethylene (PTFE) is applied to carbon paper, facing the electrode catalyst layer 2 and the electrode catalyst layer 3 of the membrane electrode assembly 12, and The fuel electrode side gas diffusion layer 5 is disposed. Thereby, the air electrode 6 and the fuel electrode 7 are comprised, respectively. A set of conductive and gas-impermeable materials having a gas flow path 8 for reaction gas flow facing a single cell and a cooling water flow path 9 for cooling water flow on the opposing main surface. A single cell 11 is formed by being sandwiched by the separator 10.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not interpreted limitedly by this illustration.
Example 1
0.98 g of hexamethylbenzene was dissolved in 10 ml of tetrachloroethane. Next, 2.0 ml (5 equivalents) of chlorosulfonic acid was added and heated at 150 ° C. for 20 hours, and then the deposited black substance was filtered. Next, after washing with chloroform, the mixture was washed in water with stirring for 2 days. This chloroform and water washing was performed three times in total to obtain 930 mg of a black solid sulfonated substance.

(Example 2)
0.72 g of mesitylene (trimethylbenzene) was dissolved in 10 ml of tetrachloroethane. Next, 2.0 ml (5 equivalents) of chlorosulfonic acid was added and heated at 150 ° C. for 20 hours, and then the deposited black substance was filtered. Next, after washing with chloroform, it was washed in water for 2 days. This chloroform and water washing was performed three times in total to obtain 607 mg of a black solid sulfonated substance.

(Comparative Example 1)
0.77 g of naphthalene was dissolved in 10 ml of tetrachloroethane. Next, 2.0 ml (5 equivalents) of chlorosulfonic acid was added and heated at 150 ° C. for 20 hours, but no black solid sulfonated substance was precipitated.

[Evaluation method]
(Confirmation of sulfonic acid group and alkyl group by infrared spectrum):
The compounds obtained in Examples 1 and 2 were confirmed by measuring the infrared spectrum (KBr tablet method) with FT / IR-460plus manufactured by JASCO. The infrared spectrum of the compound of Example 1 is shown in FIG. 3, and the infrared spectrum of the compound of Example 2 is shown in FIG. The results are shown in Table 1.

(S amount analysis by elemental analysis):
The black solid sulfonated materials obtained in Examples 1 and 2 were measured with YS-10 manufactured by YANACO, and the contents (mass%) of S (sulfur) and Cl (chlorine) were obtained.
In addition, other elements were analyzed. C (carbon) and H (hydrogen) were measured with MT-5 manufactured by YANACO. Further, O (oxygen) was measured with a VTF-900 manufactured by LECO. The results are shown in Table 1.
Since the mass% of each element is measured by three types of apparatuses, it is difficult to reach 100 mass% even if the mass% of each element is summed due to measurement errors.

(Acid value):
The black solid sulfonated material was reacted for 2 days in a 5N aqueous sodium nitrate solution, and the black solid sulfonated material was filtered through a filter. A sodium hydroxide solution was dropped into the acidic solution from which the black solid sulfonated material was removed, and the neutralization point was measured. The acid value was calculated from the amount dropped. The results are shown in Table 1.

(Analysis by solid state ¹³ C-NMR):
Measuring instrument: Nuclear magnetic resonance apparatus (JEOL-ECA-400)
Measurement conditions: Measured at a rotational speed of 5300 Hz.
The nuclear magnetic resonance spectrum of the black solid sulfonated material obtained in Example 1 is shown in FIG. 5, and the nuclear magnetic resonance spectrum of the black solid sulfonated material obtained in Example 2 is shown in FIG. The results are shown in Table 1.

(OH radical resistance):
<Fenton test>
The black solid sulfonated substance obtained in Example 1 was put in Fenton reagent (80 ° C., 3% H 2 O 2, 2 ppm Fe ²⁺ ), and the time until the color changed visually was measured at 80 ° C. for 3 hours. did.
When the measured time was long, the OH radical resistance was excellent, and when the measured time was short, the OH radical resistance was inferior. The results are shown in Table 1.

The following can be seen from FIGS.
In Comparative Example 1, measurement was not possible because a black solid sulfonated substance was not obtained.
From confirmation of presence of sulfonic acid group and alkyl group by infrared spectrum and analysis by solid state ¹³ C-NMR, mesitylene (Example 2) is used as a starting material, and hexamethylbenzene (Example 1) is used as a starting material. The signal of the resulting black solid sulfonated material is almost unchanged, suggesting that it is the same kind of material of the present invention.
In addition, from FIG. 3 and FIG. 4, in addition to the sulfonic acid group signal, a large OH signal appeared in the infrared spectrum. Further, since S was detected by elemental analysis, the black solid sulfonated material is supported to have a sulfonic acid group.
Furthermore, a signal is observed at 2976 cm ⁻¹ in the infrared spectrum, and a signal is observed at 10 to 30 ppm also in solid ¹³ C-NMR, suggesting that the black solid sulfonated substance has an alkyl group. Is done.

In addition, aromatic solid-state signals are present in the vicinity of 130 ppm in solid ¹³ C-NMR, and since they are insoluble in halogenated solvents and water, polyaromatic cyclization is performed without breaking the aromatic ring during the reaction. Is suggested.
It was found that the acid value was higher and the number of sulfonic acid groups was larger when mesitylene (Example 2) was used as a starting material than when hexamethylbenzene (Example 1) was used as a starting material.

The OH radical resistance can be said to be an essential condition for a fuel cell in which OH radicals are generated. Under the conditions of Fe ²⁺ 2 ppm, 3% hydrogen peroxide and 80 ° C. for 3 hours, no change in color was observed for the substance of the present invention of Example 1. Therefore, OH radical resistance of 1 hour or more was exhibited even when conducted under conditions of Fe ²⁺ 10 ppm, 3% hydrogen peroxide, and 80 ° C. for 15 hours, which is 25 times stronger by simple calculation.
Therefore, as a comparative experiment, polyphenylene having a structure in which a benzene ring having no alkyl group was connected was conducted under the same conditions (Fe ²⁺ 2 ppm, 3% hydrogen peroxide, 80 ° C. for 3 hours). There was no resistance to OH radicals, and even under these conditions, 30% decomposition occurred.
As described above, it was found that the black solid sulfonated material of the present invention has extremely high OH radical resistance.

Thus, the black solid sulfonated material of the present invention obtained by adding chlorosulfonic acid as a sulfonating agent to an aromatic ring having an alkyl group and heating is high in OH radical resistance and has a sulfonic acid group. For this reason, it turns out that a proton conductive membrane, a solid acid catalyst, an ion exchanger, a membrane electrode assembly, and a fuel cell having higher performance than conventional ones can be provided by using the black solid sulfonated material of the present invention.

Black solid sulfonated material of the present invention, for the aromatic hydrocarbon compound having an aromatic ring with an alkyl group consisting of mesitylene, or hexamethylbenzene, at a molar ratio of 100 times 0.2 times chlorosulfonic It is characterized by adding a sulfonating agent comprising an acid and heating at 100 ° C. or more and 300 ° C. or less and polyaromatic cyclization , having an alkyl group and a sulfonic acid group introduced,
High proton conductivity, excellent heat resistance, excellent ion exchange capacity, catalytic performance, OH radical resistance, and low price.
According to the production method of the present invention, such a black solid sulfonated material can be easily produced at low cost, and a proton excellent in OH radical resistance using such a black solid sulfonated material. Since a conductive membrane, a catalyst, an ion exchanger, a membrane electrode assembly, and a fuel cell can be provided, the industrial utility value is high.

It is a section explanatory view of one embodiment of the membrane electrode assembly of the present invention which formed the electrode catalyst layer on both sides of the electrolyte membrane of the present invention. FIG. 2 is an exploded cross-sectional view showing a configuration of a single cell of a fuel cell equipped with the membrane electrode assembly shown in FIG. 1. 2 is an infrared spectrum of the black solid sulfonated material of the present invention obtained in Example 1. 2 is an infrared spectrum of the black solid sulfonated substance of the present invention obtained in Example 2. 2 is a graph showing the analysis result by solid state ¹³ C-NMR of the black solid sulfonated substance of the present invention obtained in Example 1. FIG. 3 is a graph showing the analysis result by solid state ¹³ C-NMR of the black solid sulfonated substance of the present invention obtained in Example 2. FIG.

DESCRIPTION OF SYMBOLS 1 Electrolyte membrane 2 Air electrode side electrode catalyst layer 3 Fuel electrode side electrode catalyst layer 4 Air electrode side gas diffusion layer 5 Fuel electrode side gas diffusion layer 6 Air electrode 7 Fuel electrode 8 Gas flow path 9 Cooling water flow path 10 Separator 11 Single cell 12 Membrane electrode assembly

Claims (11)

For the aromatic hydrocarbon compound having an aromatic ring with an alkyl group consisting of mesitylene, or hexamethylbenzene, at a molar ratio, the sulfonating agent consisting of 100 times the chlorosulfonic acid 0.2 fold addition, 100 ° C. A black solid sulfonated substance having an alkyl group and having a sulfonic acid group introduced, obtained by polyaromatic cyclization by heating at 300 ° C. or lower . The black solid sulfonated substance according to claim 1 , wherein at least three signals of 125 ppm to 150 ppm, 10 ppmm to 30 ppm, and 60 ppm to 90 ppm are present in solid state ¹³ C-NMR. The black solid sulfonated substance according to claim 1 or 2, wherein at least a signal derived from a sulfonic acid group and a signal derived from an alkyl group are present in an infrared spectrum. The black solid sulfonated substance according to any one of claims 1 to 3 , wherein S is present in the range of 2 to 30% by mass in elemental analysis. The black solid sulfonated material according to any one of claims 1 to 4 , wherein the acid value is 0.1 to 8 meq / g. A method of manufacturing a black solid sulfonated material as claimed in any one of claims 5, for the aromatic hydrocarbon compound having an aromatic ring with an alkyl group consisting of mesitylene, or hexamethylbenzene Characterized by adding a sulfonating agent comprising chlorosulfonic acid in a molar ratio of 0.2 to 100 times, and heating at 100 ° C. or more and 300 ° C. or less for polyaromatic cyclization to introduce a sulfonic acid group. A method for producing a black solid sulfonated material. An ion exchanger using the black solid sulfonated substance according to any one of claims 1 to 5 . Electrolyte membrane characterized by using a black solid sulfonated material according to any one of claims 1 to claim 5. An acid catalyst using the black solid sulfonated substance according to any one of claims 1 to 5 . A membrane / electrode assembly comprising the electrolyte membrane according to claim 8 . A fuel cell using the electrolyte membrane according to claim 8 .

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