JP2007204440A - Method for producing solid acid, and solid acid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a safe method for producing a solid acid, having a high ion-exchanging volume, catalytic performance and proton conductivity and excellent in heat resistance without using a special device, and also a proton conductive membrane, a solid acid catalyst, an ion-exchanging membrane, a membrane electrode assembly and fuel cells by using the same. <P>SOLUTION: This method for producing the solid acid is provided by heat-treating an aromatic compound having amino group and an aromatic compound having other than the amino group under a normal pressure in the presence of a polycondensation catalyst, and then sulfonating the obtained polycondensate with sulfonating agent. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a method for producing a solid acid and a solid acid. More specifically, the present invention relates to a proton conductive membrane, a solid acid catalyst, an ion exchange membrane, an ion exchange capacity, catalytic performance, high proton conductivity and excellent heat resistance. The present invention relates to a method for producing a solid acid and a solid acid produced by the production method of the present invention.

Solid acid catalysts do not require processes such as neutralization or salt removal for separation / recovery, and can produce target products with energy savings without producing unnecessary by-products. (For example, refer nonpatent literature 1).
As a result, solid acid catalysts such as zeolite, silica-alumina, and hydrous niobium have achieved great results in the chemical industry, bringing great benefits to society. In addition, Nafion described above is a very strong solid acid having hydrophilicity, and it is already known that it works as a super strong acid having an acid strength exceeding that of a liquid acid. However, Nafion is susceptible to heat and is too expensive for industrial use.
Thus, it is difficult to design an industrial process in which a solid acid catalyst is more advantageous than a liquid acid catalyst in terms of performance and cost, and it can be said that most chemical industries currently depend on a liquid acid catalyst. Under such circumstances, the appearance of a solid acid catalyst that surpasses liquid acid is desired.

  Commercially available ion exchange resins are also required to have low heat resistance and high heat resistance materials.

Under such circumstances, the solid acid in Patent Document 1 is obtained by subjecting polycyclic aromatic hydrocarbons to heat treatment in concentrated sulfuric acid or fuming sulfuric acid to simultaneously perform condensation and sulfonation to obtain an unnecessary solid acid as a polar solvent. ing.
However, in actuality, the reaction of this method first involves sulfonation when polycyclic aromatic hydrocarbons are heated in concentrated sulfuric acid or fuming sulfuric acid. Since the sulfonic acid derivative produced by this sulfonation is chemically reactive, no further condensation reaction occurs. For example, when naphthalene is used as a starting polycyclic aromatic hydrocarbon, heat treatment in concentrated sulfuric acid or fuming sulfuric acid results in 1,3,6-naphthalene trisulfonic acid or 1,3,5,7-naphthalene tetrasulfonic acid. Inevitably generated. Since these naphthalenesulfonic acid derivatives are chemically reactive, no further polycondensation reaction occurs. Generally, when the temperature exceeds 200 ° C, sulfuric acid in hot concentrated sulfuric acid or fuming sulfuric acid starts to decompose into water and sulfur trioxide, so the oxidizing power is very strong. For this reason, the bond is broken and decomposed to oxidize organic matter. Therefore, it is difficult to obtain the target solid acid. Excess concentrated sulfuric acid or fuming sulfuric acid is removed by distillation under reduced pressure at 250 ° C. or under atmospheric pressure at 300 ° C. However, it is difficult to obtain a solid acid because it is oxidized and decomposed for the above reasons. In addition, with the concentration of the reaction solution such as vacuum distillation, it is very dangerous for work due to foam expansion. However, polycyclic aromatic hydrocarbons need to be condensed in order to obtain a solid acid insoluble in the target polar solvent, but heat treatment in concentrated sulfuric acid or fuming sulfuric acid is not necessarily an efficient condensation reaction. . Further, this solid acid has a problem that it is difficult to introduce a sulfonic acid group. By elemental analysis, the ratio of sulfur atoms to carbon atoms is as low as less than 15 mol%, high performance with a lot of sulfur atoms, and high degree of freedom in molecular design, safety in work, high yield and reproducibility, There has been a need to provide materials that can be easily manufactured.

Ishihara, K; Hasegawa, A; Yamamoto, H; Angew. Chem. Int. Ed. 2001, 4077. Japanese Patent Laid-Open No. 2004-238111

The problem of the present invention is that a solid acid having high proton conductivity, excellent heat resistance, and excellent ion exchange capacity, catalyst performance, etc. has high work safety, yield, freedom of molecular design, and reproducibility. It is to submit a method that is good and easy to manufacture.

  As a result of diligent research to solve the above-mentioned problems, the present invention heat-treats an aromatic compound having an amino group and an aromatic compound having other than an amino group in the presence of a polycondensation agent under normal pressure, By sulfonating the obtained polycondensation compound with a sulfonating agent, it is possible to manufacture easily at low cost with high work safety, good reproducibility, high yield, high degree of freedom in molecular design. The present inventors have found that the solid acid produced by such a method has low cost and high performance, and have completed the present invention.

  That is, the present invention is a method in which an aromatic compound having an amino group and an aromatic compound having other than an amino group are heat-treated in the presence of a polycondensation agent at normal pressure, and the resulting polycondensation compound is sulfonated. The present invention relates to a method for producing a solid acid characterized by sulfonating with an agent.

  Moreover, this invention relates to the manufacturing method of the said solid acid whose heat processing temperature is 50-220 degreeC.

  The present invention also relates to the above-mentioned method for producing a solid acid, wherein the aromatic compound having other than an amino group is in a liquid state at 50 ° C. to 220 ° C. under normal pressure.

  Moreover, this invention relates to the solid acid characterized by being manufactured with the said manufacturing method.

  The present invention also relates to the above solid acid, wherein the molar amount of sulfur relative to carbon is 15 mol% or more and 100 mol% or less in elemental analysis.

Moreover, this invention relates to the said solid acid characterized by the acid value of a solid acid being 1-20 meq / g.

  In the method for producing a solid acid of the present invention, an aromatic compound having an amino group and an aromatic compound having other than an amino group are heat-treated in the presence of a polycondensation agent under normal pressure, and the resulting polycondensation compound is treated with It is characterized by sulfonating with a sulfonating agent. At this time, the heat treatment under normal pressure can retain active components necessary for the polycondensation reaction generated from the polycondensation agent in the reaction system, such as hydrogen halide. The polycondensation reaction can be promoted. By reacting the obtained polycondensation compound with a sulfonating agent, the amount of sulfonation to be introduced can be easily designed. Furthermore, when the nitrogen atom derived from the aromatic compound having the amino group is present arbitrarily in the solid acid structure, the nitrogen atom and the sulfonic acid group are complexly interacted with each other to form a heterocyclic ring or a quaternary amine. Conceivable. For this reason, it is considered that the proton conductivity is high and the ion exchange capacity and the catalyst performance are excellent. In addition, there is a remarkable effect that the solid acid can be easily produced with high work safety, yield, freedom of molecular design, good reproducibility, and reproducibility.

  Further, the present invention is characterized in that, in the above-described solid acid production method, the heat treatment temperature is 50 ° C. to 220 ° C. There is a further remarkable effect that the reproducibility and the freedom of molecular design are high and it can be easily produced at low cost.

Further, the present invention is characterized in that, in the above-mentioned method for producing a solid acid, the aromatic compound having other than an amino group is in a liquid state at 50 ° C. to 220 ° C. under normal pressure, and is in a liquid state. Since the contact with the polycondensation agent is further improved, the cyclization condensation reaction is facilitated more easily, and the resulting polycondensation compound is sulfonated with a sulfonated agent, resulting in high proton conductivity, Further outstanding heat resistance, ion exchange capacity, catalyst performance, etc., high safety in operation, yield, high degree of freedom in molecular design, reproducibility and easy production There is an effect.

Hereinafter, the present invention will be described in more detail.
In the present invention, an aromatic compound having an amino group and an aromatic compound having other than an amino group are heat-treated in the presence of a polycondensation agent under normal pressure, and the resulting polycondensation compound is converted with a sulfonated agent. The present invention relates to a method for producing a solid acid obtained by sulfonating. Preferably, the heat treatment temperature is 50 ° C to 220 ° C. More preferably, the heat treatment temperature is 90 ° C to 150 ° C.
In addition, the aromatic compound having other than the amino group is preferably in a liquid state at 50 ° C. to 220 ° C. under normal pressure, and heat-treated in the presence of a polycondensation agent under normal pressure, and obtained polycondensation compound Can be easily produced at low cost with high work safety, yield, reproducibility, and freedom of molecular design.
More preferably, the aromatic compound is in a liquid state at 90 ° C. to 150 ° C. under normal pressure, and is heat-treated at 90 ° C. to 150 ° C. in the presence of a polycondensation agent under normal pressure. Is sulfonated with a sulfonating agent, and a higher performance solid acid can be easily produced at a low cost with a high work safety, a high yield, a high degree of freedom in molecular design.
The liquid state here means a state in which the reaction temperature is not lower than the melting point and not higher than the boiling point, or in a state where there is a liquid part dissolved in another liquid substance at the reaction temperature, for example, at a heat treatment temperature of 100 ° C. 80.2 ° C., boiling point 218 ° C.) means that coronene (melting point: 438 to 440 ° C.) exists.

As the aromatic compound having an amino group used in the present invention, any compound containing one or more aromatic rings having an unsubstituted or substituted amino group can be used. Two or more of these can be used in combination.
Examples of the substituted amino group include dialkylamine groups such as dimethylamine group, diethylamine group, dipropylamine group, and dibutylamine group; diarylamino groups such as diphenylamine group, dinaphthylamine group, and dianthranyl group; and julolidine groups. Can be mentioned.
For example, N, N, N ′, N′-tetramethyl-1,4-phenylenediamine, N, N, N ′, N′-tetramethylbenzidine, N, N, N ′, N′-tetraethyl-1, N, N, N ', N'-tetraalkylpolyphenyldiamine derivatives such as 4-phenylenediamine, N, N, N', N'-tetraethylbenzidine, N, N, N ', N'-tetraphenylbenzidine N, N, N ', N'-tetraarylpolyphenyldiamine derivatives such as 2,3,6,7-tetrahydro-1H, 5H benzo [ij] quinolidine, polyphenyl derivatives having a julolidine group, arylene, aminonaphthalene N, N-dimethylaminonaphthalene, N, N-diethylaminonaphthalene, N, N, N ′, N′-tetraethyl-1,8-naphthalenediamine, etc., two or more having one or more amine groups or dialkylamino groups Non-limiting examples include polycyclic aromatic hydrocarbons having condensed aromatic nuclei.

  The aromatic compound having an amino group other than the amino group used in the present invention is a compound containing one or more aromatic rings, and any compound having an amino group other than the amino group can be used. Among these, it can also be used individually or in combination of 2 or more types.

  Among them, when an aromatic compound having an amino group other than an amino group that is in a liquid state at 50 ° C. to 220 ° C. under normal pressure is used as a raw material, it has higher protonic conductivity and excellent heat resistance, and has an ion exchange capacity and catalytic performance. It can be preferably used because it has excellent operational safety, yield, freedom of molecular design, reproducibility, and easy production.

  Specific examples of the aromatic compound having other than the amino group used in the present invention include benzene and substituent-containing benzene. Examples of the substituent include a halogen group, a phenyl group, an alkoxyl group, a hydroxyl group, an N-oxide group, a phenyl oxide group, a hydrazyl group, a ferdazyl group, a nitro group, a nitroso group, a hydroxyl group, a phosphoric acid group, a disulfide group, a mercaptan group, and an amide. Group, imide group, isocyanate group, vinyl group, (meth) acrylyl group, cyano group, carboxylic acid, aldehyde group, and hydrocarbon group. The hydrocarbon group may be linear or cyclic, and the cyclic hydrocarbon may be aliphatic or aromatic, and may be monocyclic or polycyclic. The hydrocarbon group may contain a substituent.

As the aromatic compound having an amino group other than the amino group used in the present invention, for example, there are many condensed aromatic rings such as naphthalene, pyrene, benzo (α) pyrene, benzoanthracene, anthracene, phenanthrene, coronene, and keklene. Examples thereof include cyclic aromatic hydrocarbons and substituent-containing polycyclic aromatic hydrocarbons.
Examples of the substituent include the above-described substituents.

Examples of the aromatic compound having an amino group other than the amino group used in the present invention include 2 aromatic rings such as biphenyl, terphenyl, quaterphenyl, kinkphenyl, sexualphenyl, septiphenyl, octiphenyl, nobiphenyl, deciphenyl, and hexaphenylbenzene. Examples thereof include polyphenyls that are aggregated at least, and polyphenyls having substituents.
Examples of the substituent include the above-described substituents.

Further, as the aromatic compound having an amino group other than the amino group used in the present invention, the above benzene, substituent-containing benzene, polycyclic aromatic hydrocarbon, substituent-containing polycyclic aromatic hydrocarbon, polyphenyl, substituent-containing poly One aromatic ring in which phenyl is bonded by an amide bond, ester bond, ether bond, sulfone bond, imide bond, urethane group, urea bond, ketone bond, carbon-carbon double bond, carbon-carbon triple bond, etc. Examples include the aromatic ring-containing compounds contained above, or aromatic ring-containing organic compounds formed by combining one or more of these bonds.
For example, polyaromatic sulfones, polystyrenes, polyphenols, polyimides, polyalkyds, polyamic acids, polymelamines, benzoguanamines, polybenzoguanamines, polybismaleimide-triazines, polyallyls, polyepoxies, polyamides , Polyamideimides, polyarylates, polyallyl sulfones, polybenzimidazoles, polycarbonates, polyether ether ketones, polyether imides, polyether ketones, polyether nitriles, polyether sulfones, poly Thioether sulfones, polyethylene terephthalates, polyamino bismaleimides, polyketones, polyphenyl ethers, polyphenyl sulfides, SAN resins, polyurethanes, polyxylates And the like can be mentioned synthetic polymers such as kind, but is not limited thereto.
More preferably, the aromatic compound having an amino group other than an amino group that is in a liquid state at 50 ° C. to 220 ° C. under normal pressure includes benzene, benzoic acid, toluene, xylene, naphthalene, 1-naphthalene carboxylic acid, and 2-naphthalene carboxylic acid. , 1-naphthol, 2-naphthol, biphenyl, pyrene, anthracene, benzoanthracene, and the like, but are not limited thereto.
The heat treatment temperature range of the present invention may be any temperature at which a polycondensation reaction occurs, and is preferably 50 ° C to 220 ° C, more preferably 90 ° C to 150 ° C.

The addition amount of the aromatic compound having an amino group in the present invention is 1 to 90% by weight with respect to 100 parts by weight of the aromatic compound having other than the amino group. More preferably, it is 10 to 50% by weight.
If the amount is less than 1% by weight, the interaction between the nitrogen atom and the sulfonic acid group is difficult to obtain, and if it exceeds 90% by weight, the polycondensation reaction is hardly promoted.

A general method for synthesizing a solid acid is a heat treatment in concentrated sulfuric acid or fuming sulfuric acid, followed by sulfonation and condensation.
The problem with this method is that sulfonation occurs first when polycyclic aromatic hydrocarbons are heat-treated in concentrated sulfuric acid or fuming sulfuric acid. Since the sulfonic acid derivative produced by this sulfonation is chemically reactive, no further condensation reaction occurs.
Generally, when the temperature exceeds 200 ° C, sulfuric acid in hot concentrated sulfuric acid or fuming sulfuric acid starts to decompose into water and sulfur trioxide, so the oxidizing power is very strong. For this reason, the bond is broken and decomposed to oxidize organic matter. To do. Excess concentrated sulfuric acid or fuming sulfuric acid is removed by distillation under reduced pressure at 250 ° C. or at 300 ° C. under normal pressure, so that it is difficult to obtain a solid acid for the above reasons. Also, vacuum distillation is very dangerous for work due to foam expansion due to concentration. However, polycyclic aromatic hydrocarbons need to be condensed in order to obtain a solid acid insoluble in the target polar solvent, but heat treatment in concentrated sulfuric acid or fuming sulfuric acid is not necessarily an efficient condensation reaction. . In addition, this synthesis method has a problem that it is difficult to introduce a sulfonic acid group, and it is difficult to arbitrarily introduce a sulfonic acid, and the yield, reproducibility, and freedom of molecular design are low.

In the present invention, first, an aromatic compound having an amino group and an aromatic compound having other than an amino group are heat-treated in a polycondensation agent under normal pressure to obtain a polycondensation compound.
Since this polycondensation compound can be easily confirmed in structure and molecular weight by IR, NMR, GPC, etc., molecular design is easy.
Second, the resulting polycondensation compound is sulfonated with a sulfonated agent. This sulfonation reaction is carried out without destroying the structure of the polycondensation compound, so that the structure and molecular weight can be easily estimated and the introduction of a sulfonic acid group is easy, so the acid value can be controlled arbitrarily, and the molecular design This is a method for producing a solid acid having a high degree of freedom.
In the present invention, in a reaction vessel containing an aromatic compound having an amino group, an aromatic compound having other than an amino group, and a polycondensation agent, the polycondensation compound thus obtained is heated under normal pressure. Sulfonation with an oxidizing agent, operation before heating under normal pressure in a reaction vessel containing an aromatic compound having an amino group, an aromatic compound having a non-amino group, and a polycondensation agent are not allowed to occur. It is presumed that this is effective because the active gas is replaced in the reaction vessel, dissolved oxygen in the reaction vessel is removed, and the solid acid produced by heat treatment is easily prevented from oxidation and the polycondensation reaction is facilitated. It is. In addition, under normal pressure in a reaction vessel containing an aromatic compound having an amino group, an aromatic compound having a non-amino group, and a polycondensation agent, the operation during the heat treatment is performed by stopping the inert gas replacement. Is done. The replacement of the inert gas may be stopped before the heat treatment or during the heat treatment. This is because an aromatic component having an amino group can be retained by carrying out heat treatment under normal pressure, so that active components necessary for the polycondensation reaction generated from the polycondensation agent in the reaction system, such as hydrogen halide, can be retained. This is because the polycondensation reaction between the compound and an aromatic compound having other than an amino group can be promoted.
The temperature of this reaction should just be the temperature which a polycondensation reaction produces, Preferably it is 50 to 220 degreeC, and 90 to 150 degreeC is more preferable.

In addition, when the aromatic compound having other than an amino group is in a liquid state at 50 ° C. to 220 ° C. under normal pressure, the contact with the polycondensation agent is further improved. This is because it is presumed to be the target.
Examples of the polycondensation agent used in the present invention include AlCl ₃ , FeCl ₃ , SbCl ₅ , BF ₃ , ZnCl ₂ , TiCl ₄ , HF, H ₃ PO ₄ , P ₂ O ₅ , Lewis acid catalyst such as polyphosphoric acid, chloride chloride Various ferritic, potassium ferricyanide, manganese dioxide, hydrogen peroxide, persulfuric acid, iodine, selenium oxide, organic peracids, various oxidizing agents, condensing agents used in Scholl reaction, solid acids and general dehydrogenation catalysts It can be mentioned, but is not limited to these.
These addition methods may be added at once, or may be added separately.
In order to promote polycondensation, a Lewis acid catalyst and an oxidizing agent may be combined.
In order to promote polycondensation, a combination of alkali metal salts such as potassium chloride, sodium chloride, potassium iodide, sodium bromide, sodium iodide, potassium bromide, etc. that lowers the melting temperature of the polycondensation agent is combined. Is also effective.

The addition amount of the polycondensation agent of the present invention may be an amount that causes a polycondensation reaction, but is more preferably 50 to 2000 parts by weight with respect to 100 parts by weight of the aromatic compound. Preferably, it is 100-500 weight part.
In the present invention, the ratio by the combination of the Lewis acid catalyst and the oxidizing agent is 0.01 to 100 parts by weight of the oxidizing agent with respect to 100 parts by weight of the Lewis acid catalyst.
The addition amount of the alkali metal halide in the present invention is 1 to 100 parts by weight of the metal halide with respect to 100 parts by weight of the Lewis acid catalyst. More preferably, it is 5 to 60 parts by weight.

The polycondensation reaction can be performed in the absence of a solvent, but can also be performed in the presence of a solvent.
As this solvent, a solvent generally used for Friedel-Crafts reaction or cationic polymerization, such as nitromethane, nitropropane, nitrobenzene and carbon disulfide, can be used.
The polycondensation compound obtained by this polycondensation reaction can be obtained by hydrolysis with an acidic aqueous solution such as dilute hydrochloric acid or dilute sulfuric acid as a method for removing excess Lewis acid.
Hydrolysis can be performed by a method of adding the polycondensation reaction solution to an acidic aqueous solution, a method of adding an acidic aqueous solution to the polycondensation reaction solution in a reaction vessel, or the like. After hydrolysis, it can be obtained by a method of taking out by filtration, a method of adding a solvent that dissolves the polycondensation reaction product and taking out it as a solution, removing the solvent from this solution, a method of obtaining by a reprecipitation method, and the like.

In the present invention, an aromatic compound having an amino group and an aromatic compound having other than an amino group are subjected to heat condensation in the presence of a polycondensation agent under normal pressure, that is, two or more aromatic rings are formed. A new condensed ring is formed in which two or more atoms are shared. A polycondensed polycyclic aromatic hydrocarbon amorphous body, which has undergone condensation and is complexly polycondensed, is produced. In general, as the number of condensed aromatic rings increases, the property becomes closer to that of graphite, and this polycondensed nitrogen atom-containing polycyclic aromatic hydrocarbon which has undergone condensation has a structure or structure determined by IR, NMR, GPC, etc. Sulfonating a nitrogen atom-containing polycyclic aromatic hydrocarbon with a molecular design such as molecular weight with a sulfonating agent retains the previous properties without breaking the bond due to oxidation, and allows the sulfonic acid group to be arbitrarily It is a production method applying the knowledge that nitrogen atoms can be arbitrarily incorporated into solid acid structures.

When the present inventors heat-treat at 50 ° C. to 220 ° C. in the presence of a polycondensation agent under normal pressure, and sulfonated the resulting polycondensation compound with a sulfonated agent, carbonization proceeds greatly. A developed hydrophobic heterocycle-containing polycyclic aromatic hydrocarbon is produced, and it is sulfonated with a sulfonating agent to produce a solid acid insoluble in water. As a result, the objective was achieved.
Examples of the sulfonating agent used in the present invention include, but are not limited to, sulfur trioxide, concentrated sulfuric acid, fuming sulfuric acid, chlorosulfuric acid, amidosulfuric acid and the like.
The addition amount of the sulfonating agent of the present invention varies depending on the kind of sulfonating agent and the amount of introduction of sulfonation, but any amount that causes sulfonation to the polycondensation compound may be used, and preferably 100 wt. 0.1 to 2000 parts by weight with respect to parts.
The reaction temperature at this time is suitably -20 ° C to 250 ° C, although the reaction temperature varies appropriately depending on the type of the sulfonating agent and the amount of sulfone group introduced.
The sulfonation reaction can be performed in the absence of a solvent, but can also be performed in the presence of a solvent. Examples of the solvent include hydrocarbon solvents such as pentane, hexane, benzene, toluene and xylene; dichloromethane, chloroform, carbon tetrachloride, dichloroethane, tetrachloroethane, trichlorofluoromethane, 1,1,2-trichloro-1,2, Halogenated hydrocarbon solvents such as 2-trifluoroethane; nitrogen-containing solvents such as nitromethane, nitroethane, nitropropane, and nitrobenzene. In addition, a solvent generally used for Friedel-Crafts reaction, cationic polymerization and the like can be appropriately selected and used suitably. These solvents may be used alone or in combination of two or more.
In configuring this polycondensation reaction system, there are no particular restrictions on the order and method of blending an aromatic compound having an amino group, an aromatic compound having other than an amino group, and a polycondensation agent, and each of them can be used simultaneously or in various ways. It is also possible to blend stepwise in the order and manner.
In addition, there are no particular restrictions on the order and method of blending the polycondensation compound and the sulphonating agent, etc. in configuring this sulphonation reaction system, and they may be blended simultaneously or stepwise in various orders and manners. Is possible.
The solid acid obtained by sulfonating with the sulfonating agent of the present invention is obtained by diluting the reaction solution with ion-exchanged water, and decanting or performing general filtration, microfiltration, ultrafiltration, reverse osmosis filtration, etc. Wash until is neutralized.

As a drying method, natural drying, hot air drying, external heating drying, spray drying, drying using microwaves, infrared rays, far infrared rays, freeze drying, or the like can be performed.

In the solid acid of the present invention, a nitrogen atom derived from an aromatic compound having an amino group is arbitrarily present in the solid acid structure, and it is assumed that the nitrogen atom and the sulfonic acid group interact in a complicated manner. Therefore, high activity is obtained, proton conductivity is high, heat resistance is high, and high ion exchange capacity, high catalyst performance, and the like are exhibited.
In the solid acid of the present invention, the molar amount of sulfur with respect to carbon is preferably 15 mol% or more and 100 mol% or less in elemental analysis. If it is less than 15 mol%, the sulfonation rate is low, it is difficult to obtain a strong acid, and the ion exchange amount, catalyst performance, and proton conductivity may be lowered.
The solid acid of the present invention preferably has an acid value of 1 to 20 meq / g. If the acid value is less than 1 meq / g, the activity is low and the function of the solid acid tends to be low, and if it exceeds 20 meq / g, the function as the solid acid tends to be impaired by dissolving in a polar solvent.

  The solid acid of the present invention can be used for proton conducting membranes, solid acid catalysts, and ion exchange membranes.

  The proton conducting membrane referred to in the present invention means a membrane having the ability to conduct protons. The solid acid of the present invention is used as a film by forming it alone or by using a binder resin or the like.

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

  The ion exchange membrane referred to in the present invention refers to a membrane that selectively transmits ions. It is used by using the solid acid of the present invention alone or carrying it on a binder resin, alumina, silica or the like.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not interpreted limitedly by this illustration.

Example 1
While flowing 60 ml / min of nitrogen into a 300 ml four-necked flask, 50 parts by weight of anhydrous aluminum chloride, 10 parts by weight of sodium chloride, 20 parts by weight of naphthalene and N, N, N ′, N′-tetramethylbenzidine (Compound 1) 10 A part by weight was charged and gently stirred for 30 minutes. Nitrogen was turned off as soon as heating was started, heated to 90 ° C., held at 90 ° C. for 30 minutes, and then heated to 100 ° C. The reaction was carried out at 100 ° C. to 105 ° C. for 4 hours. In order to cool to room temperature and deactivate excess aluminum chloride, 150 ml of dilute hydrochloric acid was added.
The supernatant was discarded and 200 ml of toluene was added to dissolve the precipitate. The resulting solution was filtered through filter paper and gradually added to 1000 ml of heptane. The obtained precipitate was filtered, and the obtained precipitate was dried at 80 ° C. overnight to obtain 27.7 g of a polycondensation reaction compound.
300 ml of a four-necked flask was charged with 27.7 parts by weight of a polycondensation reaction compound and 277 ml of 97% sulfuric acid, heated to 180 ° C. while allowing nitrogen to flow at 80 ml / min, and reacted for 5 hours. This solution was poured into 554 ml of ion-exchanged water with stirring and stirred for 1 hour. This was subjected to suction filtration and further washed with 300 ml of ion-exchanged water. Again, the precipitate was dispersed in 300 ml of ion-exchanged water, stirred for 1 hour, suction filtered, washed with ion-exchanged water until the filtrate became neutral, and then dried at 80 ° C. overnight to obtain solid acid 1. 28.1 parts by weight were obtained.
(Example 2)
Into a four-necked flask (300 ml), 50 g of anhydrous aluminum chloride, 20 g of naphthalene, and 2 parts by weight of 2,3,6,7-tetrahydro-1H, 5H benzo [ij] quinolidine (compound 2) were charged while flowing nitrogen at 60 ml / min. Gently stirred for 30 minutes. Nitrogen was turned off as soon as heating was started, heated to 90 ° C., held at 90 ° C. for 30 minutes, and then heated to 100 ° C. The reaction was carried out at 100 ° C. to 105 ° C. for 4 hours. Dilute hydrochloric acid was added to cool to room temperature and deactivate excess aluminum chloride.
This was filtered to obtain a precipitate. This was dried at 80 ° C. overnight to obtain 20 parts by weight of a polycondensation reaction compound.
A 300 ml four-necked flask was charged with 20 parts by weight of a polycondensation reaction compound and 200 ml of 97% sulfuric acid, heated to 180 ° C. with nitrogen flowing at 80 ml / min, and reacted for 5 hours. This solution was poured into 300 ml of ion-exchanged water with stirring, and stirred for 1 hour. This was suction filtered and washed with 300 ml of ion-exchanged water. The precipitate was again dispersed in 300 ml of ion-exchanged water, stirred for 1 hour, filtered by suction, washed with ion-exchanged water until the filtrate became neutral, and then dried at 80 ° C. overnight. 18.1 parts by weight were obtained.
(Example 3)
While flowing 60 ml / min of nitrogen into a 300 ml four-necked flask, 50 parts by weight of anhydrous aluminum chloride, 10 parts by weight of sodium chloride, 20 parts by weight of naphthalene and N, N, N ′, N′-tetraphenylbenzidine (Compound 3) 4 A part by weight was charged and gently stirred for 30 minutes. Nitrogen was stopped at the same time as heating was started, and the mixture was heated to 110 ° C and reacted at 110 ° C to 115 ° C for 4 hours. Dilute hydrochloric acid was added to cool to room temperature and deactivate excess aluminum chloride.
This was filtered to obtain a precipitate. This was dried at 80 ° C. overnight to obtain 21 g of a polycondensation reaction compound.
A 300 ml four-necked flask was charged with 21 g of a polycondensation reaction compound and 210 ml of 97% sulfuric acid, heated to 180 ° C. with nitrogen flowing at 80 ml / min, and reacted for 5 hours. This solution was poured into 200 ml of ion-exchanged water with stirring and stirred for 1 hour. This was suction filtered and washed with 300 ml of ion-exchanged water. The precipitate was again dispersed in 300 ml of ion-exchanged water, stirred for 1 hour, suction filtered, washed with ion-exchanged water until the filtrate became neutral, and then dried overnight at 80 ° C. 19.9 parts by weight were obtained.

次に、実施例１〜３で得られた固体酸１〜３および比較例１で得られた固体酸４の酸価の測定を下記の方法で行った。 (Comparative Example 1)
20 g of naphthalene was added to 200 ml of concentrated sulfuric acid (97% by mass) and heated at 200 ° C. for 15 hours for sulfonation. Next, excess concentrated sulfuric acid was removed by distillation under reduced pressure at 250 ° C. to obtain a black solid powder. Add 600 ml of ion-exchanged water, stir for 1 hour, let stand overnight, then decant, add 600 ml of ion-exchanged water to the precipitate, stir for 1 hour, and let stand overnight. This was subjected to suction filtration and washed with ion-exchanged water until the filtrate became neutral to obtain 9.2 g of a comparative solid acid 4.

(Yield comparison)
Next, Table 1 shows the yields of the solid acids 1 to 3 obtained in Examples 1 to 3 and the solid acid 4 obtained in Comparative Example 1 with respect to the charged raw material amounts in Examples 1 to 3 and Comparative Example 1. .
As a result, the yield of about 1.8 to 2.0 times could be obtained in any of Examples 1 to 3 as compared with the conventional method. Thereby, it turned out that a solid acid can be obtained more efficiently.


[Calculation formula for solid acid yield (%)]

Yield (%) = Yield of solid acid obtained (g) / Total amount of raw materials charged (g) × 100

Next, the acid values of the solid acids 1 to 3 obtained in Examples 1 to 3 and the solid acid 4 obtained in Comparative Example 1 were measured by the following method.

(Measurement method of acid value)
The black powders (solid acids 1 to 3 obtained in Examples 1 to 3 and solid acid 4 obtained in Comparative Example 1) were washed with pure water. Next, it was reacted with black powder in a 2N aqueous sodium nitrate solution for 48 hours, and the black powder was filtered with a filter. A sodium hydroxide solution was dropped into the acidic solution from which the black powder was removed, and the neutralization point was measured in a nitrogen stream. The acid value was calculated from the amount dropped. Conventionally, the neutralization point has been obtained by dropping sodium hydroxide directly on the black powder, but the acid value may be measured more accurately by using this method. The results are shown in Table 2.
As a result, an acid value of about 4.3 to about 4.8 times that of any of Examples 1 to 3 was obtained as compared with the conventional method. As a result, it was found that more acid groups were introduced.

  Next, the measurement of the sulfur content (mol%) of the solid acids 1 to 4 obtained in Examples 1 to 4 and the solid acid obtained in Comparative Example 1 was performed by the following method.

(Elemental analysis)
The solid acids 1 to 3 obtained in Examples 1 to 3 and the solid acid 4 (both black powder) obtained in Comparative Example 1 were burned under an oxygen stream, and CHSN-932 (manufactured by LECO, USA) was used. Then, the sulfur content (mol%) relative to 1 mol of carbon was measured. The results are shown in Table 3.

  The sulfur content was 1.7 or more times higher in any of Examples 1 to 3 than in the past, and it was found that sulfonic acid groups were introduced as compared with the prior art.

Next, the solid acid catalyst performance of the solid acids 1 to 3 obtained in Examples 1 to 3 and the solid acid 4 obtained in Comparative Example 1 was evaluated by the following method.

(Solid acid catalyst performance evaluation method)
0.2 g of each of solid acids 1 to 3 obtained in Examples 1 to 3 and solid acid 4 obtained in Comparative Example 1 was added as a catalyst to a mixed solution of 0.1 mol of acetic acid and 1 mol of ethyl alcohol under an argon atmosphere. Then, the mixture was stirred at 70 ° C. for 6 hours, and the amount (mol) of ethyl acetate produced by the acid-catalyzed reaction during the reaction after 1 hour was examined by gas chromatography. The results are shown in Table 5.

  A polycondensation compound obtained by heat-treating an aromatic compound having an amino group and an aromatic compound having other than an amino group with a polycondensation agent under normal pressure, such as the solid acids 1 to 3 obtained in Examples 1 to 3 Is synthesized by sulfonating with a sulfonating agent to produce a solid acid having a high yield, a high acid value (4.2 meq / g to 4.8 meq / g) and a high sulfur content (19 mol%) based on the raw materials. Can be provided. Compared with Comparative Example 1, the yield is about 1.8 to 2.0 times higher, the efficiency is higher, the acid value is about 4 times, and the sulfur content is about 1.7 times. The exchange capacity is high.

  Furthermore, when the solid acid catalyst performance of the solid acids 1 to 3 obtained in Examples 1 to 3 was investigated, the catalyst performance was 1.7 times maximum compared to the conventional one, and a high performance solid acid catalyst could be provided. understood.

  In this way, heat treatment with a polycondensation agent under normal pressure, and by synthesizing the resulting polycondensation compound by sulfonation with a sulfonating agent, compared to conventional heat treatment in concentrated sulfuric acid or fuming sulfuric acid, It is possible to provide a solid acid having high operational safety, yield and reproducibility, high catalyst performance, proton conductivity and ion exchange capacity.

In the method for producing a solid acid of the present invention, an aromatic compound having an amino group and an aromatic compound having a non-amino group are heat-treated in the presence of a polycondensation agent under normal pressure, and sulfonated with a sulfonated agent. Is characterized by high proton conductivity, excellent heat resistance, high ion exchange capacity, high catalyst performance, etc. Since it has a remarkable effect that it can be easily manufactured with good reproducibility, the industrial utility value is high.

Claims (6)

  An aromatic compound having an amino group and an aromatic compound having other than the amino group are heat-treated in the presence of a polycondensation agent under normal pressure, and the resulting polycondensation compound is sulfonated with a sulfonated agent. A method for producing a solid acid.   The method for producing a solid acid according to claim 1, wherein the heat treatment temperature is 50 to 220 ° C.   The method for producing a solid acid according to claim 1 or 2, wherein the aromatic compound having other than an amino group is in a liquid state at 50 ° C to 220 ° C under normal pressure.   A solid acid produced by the production method according to claim 1.   The solid acid according to claim 4, wherein the molar amount of sulfur with respect to carbon is 15 mol% or more and 100 mol% or less by elemental analysis. 6. The solid acid according to claim 4, wherein the acid value of the solid acid is 1 to 20 meq / g.