JPWO2007029496A1 - Fluorinated sulfonic acid group-introduced amorphous carbon, its production method and its use - Google Patents

Abstract

In X-ray photoelectron spectroscopy, at least one S2p photoelectron peak is detected at a binding energy of 165 eV to 175 eV, and at least one F1s photoelectron peak is detected at a binding energy of 675 eV to 695 eV. Fluorinated sulfonic acid group-introduced amorphous material characterized in that at least a diffraction peak on the carbon (002) plane having a half-value width (2θ) of 5 to 30 ° is detected in diffraction, and exhibits acid catalytic activity and proton conductivity Provide carbon. This substance can be used as a proton conductive material or a solid acid catalyst.

Description

  The present invention relates to amorphous carbon into which a fluorine atom and a sulfonic acid group are introduced (hereinafter sometimes referred to as “fluorinated sulfonic acid group-introduced amorphous carbon”). This fluorinated sulfonic acid group-introduced amorphous carbon can be used as a proton conductive material or a solid acid catalyst.

  A polymer electrolyte fuel cell is a type of fuel cell in which a proton conducting membrane is arranged between a fuel electrode and an air electrode, and is expected to be a vehicle-mounted fuel cell because it can be reduced in size and weight. ing.

  Nafion (registered trademark, DuPont) is used as a proton conductive membrane of a polymer electrolyte fuel cell. However, since Nafion has low thermal and chemical stability, the battery cannot be operated at a high temperature. In order to obtain a sufficient output even at a low temperature in a fuel cell using Nafion, it is necessary to use a large amount of platinum catalyst (equivalent to 40 to 60% by weight of the air electrode) in the air electrode, which increases the cost of the fuel cell. is doing. In addition, the cost of Nafion itself is high. Currently, development of a new proton conductive material to replace Nafion is in progress, but it has not yet been put into practical use (Non-patent Document 1, Patent Document 1, Patent Document 2).

  By the way, solid acid catalysts do not require processes such as neutralization and salt removal for separation / recovery, and can produce the desired product with energy savings without producing unnecessary by-products. Research has been carried out (Non-Patent Document 2). As a result, solid acid catalysts such as zeolite, silica-alumina, and hydrous niobium have achieved great results in the chemical industry and have brought great benefits to society. Nafion mentioned above is also a very strong solid acid (solid superacid) having hydrophilicity, and it is already known that it works as a superacid having an acid strength exceeding that of a liquid acid. However, polymeric solid acid catalysts such as Nafion are vulnerable to heat and are 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 in terms of performance and cost is desired.

HIGH TEMPETATURE MEMBRANES FOR SOLID POLYMER FUEL CELLS, ETSU F / 02/00189 / REP, Contractor Johnson Matthey Technology Centre, Prepared by Martin Hogarth Xavier Glipa, Crown Copyright, 2001, Pi-15, especially page 4, Table 11 Ishihara, K; Hasegawa, A; Yamamoto, H. Angew. Chem. .Int. Ed. 2001, 40, 4077. JP 2003-217341 A JP 2003-342241 A

  As described above, there is a great social demand for proton conductive materials and substances that can be used as solid acid catalysts. The present invention has been made under such a background, and an object thereof is to provide a novel substance that can be used as a proton conductive material and a solid acid catalyst.

As a result of intensive studies to solve the above problems, the present inventor treated amorphous hydrocarbons or amorphous carbon obtained by heat-treating amorphous carbon in concentrated sulfuric acid or fuming sulfuric acid with F ₂ . As a result, it was found that a material having proton conductivity and an acid catalyst function and having high thermal and chemical stability was obtained, and based on this finding, the present invention was completed.

That is, the present invention provides the following (1) to (15).
(1) Amorphous carbon into which a fluorine atom and a sulfonic acid group are introduced.
(2) The amorphous carbon according to (1), wherein the sulfonic acid density is 0.1 to 8 mmol / g.
(3) The amorphous carbon according to (1) or (2), wherein the proton conductivity is 0.01 to 10 Scm ⁻¹ (according to an alternating current impedance method at a temperature of 80 ° C. and a humidity of 100%).
(4) The sulfur content is 0.3 wt% to 40 wt%, and the fluorine content is 0.1 wt% to 50 wt%, according to any one of (1) to (3) Amorphous carbon.
(5) The sulfur content on the surface is 0.01 to 0.2 in terms of the elemental ratio of sulfur to carbon (S / C), and the fluorine content on the surface is the elemental ratio of fluorine to carbon (F / C) in the range of 0.01 to 0.5. The amorphous carbon according to any one of (1) to (4).
(6) In X-ray photoelectron spectroscopy, at least one S2p photoelectron peak is detected at a binding energy of 165 eV to 175 eV, and at least one F1s photoelectron peak is detected at a binding energy of 675 eV to 695 eV. The amorphous carbon according to any one of (1) to (5).

(7) The amorphous carbon according to any one of (1) to (6), wherein at least a diffraction peak of a carbon (002) plane having a half width (2θ) of 5 to 30 ° in powder X-ray diffraction is detected.
(8) Amorphous carbon according to any one of (1) to (7), obtained by fluorinating amorphous carbon obtained by heat-treating a compound containing carbon in concentrated sulfuric acid or fuming sulfuric acid.
(9) The amorphous carbon according to (8), wherein the fluorination treatment of the amorphous carbon into which the sulfonic acid group has been introduced is contact with F _{2 at} −70 ° C. to 200 ° C.
(10) A solid acid catalyst containing the amorphous carbon according to any one of (1) to (9).
(11) A proton conductive material containing the amorphous carbon according to any one of (1) to (9).

(12) The method according to any one of (1) to (9), including a step of heat-treating a compound containing carbon in concentrated sulfuric acid or fuming sulfuric acid, and a step of fluorinating amorphous carbon obtained by the step. A process for producing amorphous carbon into which a fluorine atom and a sulfonic acid group are introduced.
(13) The step of fluorinating amorphous carbon into which sulfonic acid groups have been introduced is a step of bringing amorphous carbon into which sulfonic acid groups have been introduced into contact with F _{2 at} -70 ° C to 200 ° C. A method for producing amorphous carbon into which a fluorine atom and a sulfonic acid group are introduced.
(14) The heat-treated product is washed with water after the step of heat-treating the compound containing carbon in concentrated sulfuric acid or fuming sulfuric acid and before the step of fluorinating amorphous carbon ( A method for producing amorphous carbon into which a fluorine atom and a sulfonic acid group described in 12) or (13) are introduced.
(15) After the step of heat-treating the compound containing carbon in concentrated sulfuric acid or fuming sulfuric acid and before the step of fluorinating amorphous carbon, the heat-treated product is subjected to cation exchange in a basic aqueous solution. The method for producing amorphous carbon into which a fluorine atom and a sulfonic acid group are introduced according to (12) or (13), wherein the treatment is further performed, followed by proton exchange treatment in an acidic aqueous solution, followed by washing with water.

  The fluorinated sulfonic acid group-introduced amorphous carbon provided by the present invention is excellent in proton conductivity, acid catalyst function, thermal stability, chemical stability, and can be produced at low cost. It is very useful as a conductive material and a solid acid catalyst.

Photoelectron spectroscopic spectrum (A: S2p, B: F1s) of amorphous carbon (raw material: glucose) introduced with fluorinated sulfonic acid group. X-ray powder diffraction pattern of fluorinated sulfonic acid group-introduced amorphous carbon (raw material: glucose).

Hereinafter, the present invention will be described in detail.
[1] Fluorinated sulfonic acid group-introduced amorphous carbon The present invention relates to fluorinated sulfonic acid group-introduced amorphous carbon. The “amorphous carbon” in the present invention refers to a substance composed of carbon and does not have a clear crystal structure such as diamond or graphite, and more specifically, in powder X-ray diffraction, It means a substance in which no peak is detected or a broad peak is detected.

The fluorinated sulfonic acid group-introduced amorphous carbon of the present invention includes those having the following properties (A) to (F).
(A) The sulfonic acid density is 0.1 to 8 mmol / g.
(B) The proton conductivity is 0.01 to 10 Scm ⁻¹ (according to the AC impedance method at a temperature of 80 ° C. and a humidity of 100%).
(C) The sulfur content is 0.3 wt% to 40 wt%, and the fluorine content is 0.1 wt% to 50 wt%. (D) The sulfur content on the surface is relative to carbon. The sulfur element ratio (S / C) is 0.01 to 0.2, and the fluorine content on the surface is fluorine to carbon element ratio (F / C) 0.01 to 0.5.
(E) In X-ray photoelectron spectroscopy, at least one S2p photoelectron peak is detected at a binding energy of 165 eV to 175 eV, and at least one F1s photoelectron peak is detected at a binding energy of 675 eV to 695 eV. .
(F) In powder X-ray diffraction, at least a diffraction peak on the carbon (002) plane having a half width (2θ) of 5 to 30 ° is detected.

Regarding the property (A), the sulfonic acid density may be 0.1 to 8 mmol / g, preferably 1 to 8 mmol / g, and more preferably 3 to 8 mmol / g.
Regard to the nature of the (B), proton conductivity may be a 0.01～10Scm ^-1 but is preferably 0.01～1.0Scm ^-1, further preferably 0.01~0.11Scm ^-1 (the proton The conductivity is a value measured by the AC impedance method under the conditions of a temperature of 80 ° C. and a humidity of 100%.)

Regarding the property (C), the sulfur content may be 0.3 wt% to 40 wt%, preferably 0.5 wt% to 40 wt%, and 1.0 wt% to 30 wt%. More preferably, it is% by weight. Further, the fluorine content may be 0.1 to 50% by weight, preferably 0.2% to 40% by weight, and more preferably 0.2% to 30% by weight. preferable.
Regarding the property (D), one or more S2p and F1s diffraction peaks may be detected.
Regarding the property (E), the detected diffraction peak may be other than the (002) plane, but it is preferable that only the (002) plane diffraction peak is detected.

[2] Method for Producing Fluorinated Sulfonic Acid Group-Introduced Amorphous Carbon The method for producing fluorinated sulfonic acid group-introduced amorphous carbon according to the present invention comprises a step of heat treating a compound containing carbon in concentrated sulfuric acid or fuming sulfuric acid And a step of fluorinating the amorphous carbon obtained by the above step.
When a compound containing carbon is heat-treated in concentrated sulfuric acid or fuming sulfuric acid, carbonization, sulfonation, and condensation between rings occur. As a result, amorphous carbon having a sulfonic acid group introduced is produced. In addition, by fluorinating this sulfonic acid group-introduced amorphous carbon, amorphous carbon having both fluorine atoms and sulfonic acid groups introduced therein is produced.

  Heat treatment of a compound containing carbon in concentrated sulfuric acid or fuming sulfuric acid is necessary to produce amorphous carbon with a high sulfonic acid density in an inert gas stream such as nitrogen or argon, or in a dry air stream. It is. A more preferable treatment is heating while blowing an inert gas such as nitrogen or argon or dry air into concentrated sulfuric acid or fuming sulfuric acid to which an organic compound or amorphous carbon is added. Aromatic sulfonic acid and water are produced by the reaction of concentrated sulfuric acid and an aromatic compound, and this reaction is an equilibrium reaction. Therefore, when the amount of water in the reaction system increases, the reverse reaction proceeds faster, so that the amount of sulfonic acid introduced into amorphous carbon is significantly reduced. Amorphous carbon with a high sulfonic acid density is synthesized by reacting in an inert gas or in a dry air stream, or reacting while blowing these gases into the reaction system, and actively removing water from the reaction system. can do.

In the heat treatment, partial carbonization, cyclization, condensation and the like of the compound containing carbon are allowed to proceed, and sulfonation is caused. Therefore, the heat treatment temperature is not particularly limited as long as the reaction is allowed to proceed, but industrially, it is 50 ° C to 350 ° C, preferably 100 ° C to 250 ° C. When the treatment temperature is less than 50 ° C, the condensation and carbonization of the organic compound may not be sufficient, and carbon formation may be insufficient. When the treatment temperature exceeds 350 ° C, thermal decomposition of the sulfonic acid group may occur. It may happen.
The heat treatment time can be appropriately selected depending on the compound containing carbon to be used, the treatment temperature and the like, but is usually 0.01 to 500 hours, preferably 0.1 to 100 hours, and more preferably 0.5 to 50 hours.

The amount of concentrated sulfuric acid or fuming sulfuric acid to be used is not particularly limited, but is usually 0.1 to 1000 mol, preferably 1.0 to 50.0 mol, more preferably 2.0 to 36.0 mol, with respect to 1 mol of the compound containing carbon. is there.
As the compound containing carbon, an organic compound or amorphous carbon can be used.
As the organic compound, aromatic hydrocarbons can be used, but other organic compounds such as glucose, sugar (sucrose), natural products such as cellulose, synthetic polymers such as polyethylene and polyacrylamide. A compound may be used. The aromatic hydrocarbons may be polycyclic aromatic hydrocarbons or monocyclic aromatic hydrocarbons, for example, benzene, naphthalene, anthracene, perylene, coronene, etc. can be used, preferably Naphthalene or the like can be used. Only one type of organic compound may be used, but two or more types may be used in combination. Further, it is not always necessary to use a purified organic compound, and for example, heavy oil containing aromatic hydrocarbons, pitch, tar, asphalt and the like may be used.

  When using natural products such as glucose and cellulose or synthetic polymer compounds as raw materials, these materials are heated in an inert gas stream and partially carbonized before heat treatment in concentrated sulfuric acid or fuming sulfuric acid. It is preferable to keep it. The heating temperature at this time is usually 100 to 400 ° C., and the treatment time is usually 0.1 to 100 hours. The state of partial carbonization is preferably such that a diffraction peak on the (002) plane having a half width (2θ) of 30 ° is detected in the powder X-ray diffraction pattern of the heat-treated product.

Fluorination of the sulfonic acid group-introduced amorphous carbon is carried out by contacting the sulfonic acid group-introduced amorphous carbon with F _{2 in} a batch-type reaction vessel or a flow-type reaction vessel. F ₂ to be contacted may be pure or diluted with an inert gas such as Ar or He. When contacting the F ₂ in the reaction vessel of a batch-type, 1 kPa~100 kPa of F ₂ is preferred. The contacting temperature is -70 ° C to 200 ° C, preferably -70 ° C to 25 ° C.
It is preferable to wash the heat-treated product after the heat treatment step and before the fluorination treatment step. For washing with water, distilled water at room temperature to 100 ° C., ion exchange water, and tap water may be used. Decantation, filtration, and centrifugation are preferred for separation of water and solids after washing. Industrially, the heat-treated product may be once washed in a basic aqueous solution (cation exchange treatment), then washed with an acidic aqueous solution (proton exchange treatment), and then washed with water.

[3] Use of fluorinated sulfonic acid group-introduced amorphous carbon The fluorinated sulfonic acid group-introduced amorphous carbon of the present invention has high proton conductivity and an excellent acid catalyst function, and also has heat resistance, chemical properties. Since it is excellent in stability and cost, it is very useful as a proton conductive material (for example, a proton conductive membrane for a fuel cell), a solid acid catalyst, an ion exchanger, an ion selective material, and the like.

  As in the present invention, by introducing both sulfonic acid and fluorine into amorphous carbon, it is estimated that the hydrophilic environment (solid acidic environment) due to the sulfonic acid group in amorphous carbon is formed more strongly. Is done. As a result, when used as a proton conducting material, a higher proton conductivity can be obtained by forming a proton conducting path with higher conductivity. Further, when used as a solid acid catalyst, it is particularly effective for the reaction of an organic compound having a hetero element such as an oxygen-containing organic compound. The hydrophilic field enhanced by the introduction of fluorine contributes to both effective adsorption of the reaction substrate to the active site and acid catalysis, thus making it a higher performance catalyst.

  When preparing a proton conductive material or a solid acid catalyst from the fluorinated sulfonic acid group-introduced amorphous carbon of the present invention, these may consist only of the fluorinated sulfonic acid group-introduced amorphous carbon of the present invention. Other components may be included.

Hereinafter, the present invention will be described in more detail with reference to examples.
First, the measurement apparatus and measurement method used in this example will be described.
X-ray photoelectron spectroscopy spectrum: measured using ESCA3200 (manufactured by Shimadzu Corporation).
The element ratio on the surface of the sample was measured by X-ray photoelectron spectroscopy.
Elemental analysis (sulfur): A combustion elemental analyzer CHNS-932 (LECO, USA) was used.
Elemental analysis (fluorine): Combustion type elemental analyzer SX-Elements Micro Analyzer YS-10 (yanaco) was used.
X-ray analyzer: Geigerflex RAD-B, CuKα (manufactured by Rigaku Corporation) was used.

Gas chromatograph mass spectrometer GCMS-QP5050A (manufactured by Shimadzu Corporation) for product identification and quantification by catalytic reaction
Element analyzer using flash combustion: CHSN-932 (manufactured by LECO, USA) was used.
Measurement of proton conductivity: Measured by the AC impedance method. That is, a film-like sample with a diameter of 10 mm placed under 100% relative humidity is sandwiched between platinum electrodes, sealed in a sealed cell, and using an impedance analyzer (HYP4192A), frequency 5-13 MHz, applied voltage 12 mV, temperature 20 The absolute value and phase angle of the cell impedance were measured at ℃, 50 ℃ and 100 ℃. The obtained data was subjected to complex impedance measurement using a computer at an oscillation level of 12 mV, and proton conductivity was calculated.
Measurement of sulfonic acid density: It was determined by dispersing 1 g of the produced material in 100 mL of distilled water and titrating with 0.1 M aqueous sodium hydroxide. The neutralization point was determined using a pH meter.

[Example 1] Production of fluorinated sulfonic acid group-introduced amorphous carbon from glucose
When 10 g of D-glucose is heated in an inert gas stream at 400 ° C. for 15 hours, a brown organic powder [(002) plane diffraction peak having a half-value width (2θ) of 30 ° is observed. ] Was obtained. 10 g of this powder was added to 150 mL of 15% weight SO ₃ fuming sulfuric acid, and heated at 150 ° C. for 15 hours while blowing nitrogen gas at 30 ml / min to obtain a black solid. This black solid was washed with 300 mL of distilled water, and this operation was repeated until the sulfuric acid in the distilled water after washing was below the detection limit of elemental analysis to obtain amorphous carbon into which a sulfonic acid group was introduced. This material was placed in a 300 mL stainless steel vacuum vessel, evacuated at 150 ° C. for 1 hour (1 kPa or less), then cooled to room temperature, and 70 kPa of F ₂ was introduced into the vessel at room temperature. After 3 hours, evacuate the container, raise the temperature to 150 ° C, remove excess hydrogen fluoride, and then wash this black solid with 300 mL of distilled water. This operation was repeated until the detection limit was reached, thereby obtaining amorphous carbon into which a fluorinated sulfonic acid group was introduced. As a result of elemental analysis, this material had a sulfur content of 3% by weight and a fluorine content of 1% by weight. In the X-ray photoelectron spectrum of this material, an S2p peak due to a sulfonic acid group was detected at 165 to 170 eV (FIG. 1 left), and an F1s peak due to a fluorine atom was detected at 680 to 690 eV (FIG. 1 right). The elemental ratio of sulfur to carbon (S / C) on the surface of this material was 0.03, and the elemental ratio of fluorine to carbon (F / C) on the surface was 0.05. In the powder X-ray diffraction pattern of the obtained fluorinated sulfonic acid group-introduced amorphous carbon powder, a diffraction peak on the carbon (002) plane was confirmed (FIG. 2). The half-value width (2θ) of the (002) plane diffraction peak was 10 °. In addition, the sulfonic acid density of the amorphous carbon into which the sulfonic acid residue was introduced was 1.4 mmol / g.

The catalytic ability of this material was investigated by pinacol transfer reaction. After putting 0.2g of the above material into 42.3mL of pinacol and reacting at 130 ° C for 2 hours, the product (target product: pinacolone, byproduct: 2,3-dimethyl-1,3butadiene) is gas chromatograph mass spectrometer. Analyzed with As a result, it showed higher acid catalyst activity (conversion 92.5%) than any conventional solid acid (Table 1).
By forming this fluorinated sulfonic acid group-introduced amorphous carbon powder by pressure molding (manufactured by JASCO Corporation, 10 mmΦ tablet molding machine, molding conditions: 400 kg / cm ² , room temperature, 1 minute), a thickness of 0.7 mm, A disk having a diameter of 10 mm was prepared, platinum was vapor-deposited on one side of the disk, and proton conductivity was measured by the AC impedance method described above. The proton conductivity was confirmed to be 1.1 × 10 ⁻¹ Scm ⁻¹ . This result indicates that the sulfonic acid group-introduced amorphous carbon has proton conductivity comparable to that of Nafion.

[Example 2] Production of amorphous fluorinated sulfonic acid group-introduced amorphous carbon from heavy oil
A black solid was obtained by adding 150 g of 15% wt SO ₃ fuming sulfuric acid to 10 g of heavy oil and heating at 100 ° C. for 1 hour while blowing nitrogen gas at 30 ml / min. This black solid was washed with 300 mL of distilled water, and this operation was repeated until the sulfuric acid in the distilled water after washing was below the detection limit of elemental analysis to obtain amorphous carbon into which a sulfonic acid group was introduced. This material was placed in a 300 mL stainless steel vacuum vessel, evacuated at 150 ° C. for 1 hour (1 kPa or less), then cooled to room temperature, and 70 KPa of F ₂ was introduced into the vessel at room temperature. After 3 hours, evacuate the container, raise the temperature to 150 ° C, remove excess hydrogen fluoride, and then wash this black solid with 300 mL of distilled water. This operation was repeated until the detection limit was reached, thereby obtaining amorphous carbon into which a fluorinated sulfonic acid group was introduced. As a result of elemental analysis, the sulfur content of this material was 11% by weight, and the fluorine content was 1% by weight. In the X-ray photoelectron spectrum of this material, an S2p peak due to a sulfonic acid group was detected at 165 to 170 eV, and a peak due to F1s was detected at 680 to 690 eV. The elemental ratio of sulfur to carbon (S / C) on the surface of this material was 0.1, and the elemental ratio of fluorine to carbon (F / C) on the surface was 0.06. In the powder X-ray diffraction pattern of the obtained fluorinated sulfonic acid group-introduced amorphous carbon powder, a diffraction peak on the carbon (002) plane was confirmed. The half width (2θ) of the diffraction peak on the (002) plane was 20 °. In addition, the sulfonic acid density of the sulfonic acid residue-introduced amorphous carbon was 4.5 mmol / g.

The catalytic ability of this material was investigated by pinacol transfer reaction. After putting 0.2g of the above material into 42.3mL of pinacol and reacting at 130 ° C for 2 hours, the product (target product: pinacolone, byproduct: 2,3-dimethyl-1,3butadiene) is gas chromatograph mass spectrometer. Analyzed with As a result, it showed higher catalytic activity (conversion 98.5%, selectivity of target pinacolone 90.0%) and selectivity than the material of Example 1 having higher acid catalytic activity than any conventional solid acid (Table). 1).
By forming this sulfonic acid group-introduced amorphous carbon powder by pressure molding (manufactured by JASCO Corporation, 10 mmΦ tablet molding machine, molding conditions: 400 kg / cm ² , room temperature, 1 minute), the thickness is 0.7 mm and the diameter is 10 mm. After producing a disk and depositing platinum on one side of the disk, proton conductivity was measured by the AC impedance method described above. The proton conductivity was confirmed to be 2.1 × 10 ⁻¹ Scm ⁻¹ . This result shows that the sulfonic acid group-introduced amorphous carbon has proton conductivity higher than that of Nafion.

[Comparative Example] Sulfonic acid group-introduced amorphous carbon synthesized from glucose In the X-ray photoelectron spectrum of the sulfonic acid group-introduced amorphous carbon synthesized by the method of Example 1, an S2p peak due to the sulfonic acid group was detected at 165 to 170 eV. However, no peak due to F1s was detected between 680 and 690 eV. As a result of elemental analysis, the sulfur content in this material was 3% by weight. The elemental ratio of sulfur to carbon (S / C) on the surface of this material was 0.03. In the powder X-ray diffraction pattern of the obtained sulfonic acid group-introduced amorphous carbon powder, a diffraction peak on the carbon (002) plane was confirmed. The half-value width (2θ) of the (002) plane diffraction peak was 10 °. In addition, the sulfonic acid density of the amorphous carbon into which the sulfonic acid residue was introduced was 1.4 mmol / g.

The catalytic ability of this material was investigated by pinacol transfer reaction. After 0.2g of the above material was put into 42.3mL of pinacol and reacted at 130 ° C for 2 hours, the product (target product: pinacolone, byproduct: 2,3-dimethyl-1,3butadiene) was gas chromatograph mass spectrometer. Analyzed with As a result, the acid catalyst activity (conversion rate: 35.0%) was much lower than that of the materials of Examples 1 and 2 (Table 1).
By forming this sulfonic acid group-introduced amorphous carbon powder by pressure molding (manufactured by JASCO Corporation, 10 mmΦ tablet molding machine, molding conditions: 400 kg / cm ² , room temperature, 1 minute), the thickness is 0.7 mm and the diameter is 10 mm. After producing a disk and depositing platinum on one side of the disk, proton conductivity was measured by the AC impedance method described above. As a result, it was confirmed that the proton conductivity of this material was 5 × 10 ⁻² cm −1 which is lower than the proton conductivity of the materials of Examples 1 and ² .

[Reference Example] Production of sulfonic acid group-introduced amorphous carbon including washing step (1) Production of sulfonic acid group-introduced amorphous carbon from glucose
When 10 g of D-glucose is heated in an inert gas stream at 400 ° C. for 15 hours, a brown organic powder [(002) plane diffraction peak having a half-value width (2θ) of 30 ° is observed. ] Was obtained. 5 g of this powder was added to 200 mL of 15 wt% SO ₃ fuming sulfuric acid and heated at 150 ° C. for 15 hours while flowing nitrogen gas at 30 ml / min to obtain a black solid. This black solid was washed with 300 mL of distilled water, and this operation was repeated until the sulfuric acid in the distilled water after washing was below the detection limit of elemental analysis to obtain amorphous carbon into which a sulfonic acid group was introduced. A chemical shift due to a condensed aromatic carbon 6-membered ring appears near 130 ppm in the ¹³ C nuclear magnetic resonance spectrum of the resulting amorphous carbon powder with sulfonic acid group introduced. The X-ray photoelectron spectroscopy shows that the sulfonic acid group has a binding energy of 168 eV. S2p photoelectron peak derived from sulfur was detected. In the powder X-ray diffraction pattern of the resulting sulfonic acid group-introduced amorphous carbon powder, a diffraction peak on the carbon (002) plane was confirmed. The half width (2θ) of the diffraction peak on the (002) plane was 20 °. As a result of elemental analysis, the sulfur content in this material was 3% by weight. The sulfonic acid residue-introduced amorphous carbon had a sulfonic acid density of 3.5 mmol / g, and an elemental ratio H / C of hydrogen to carbon of 0.29.
This sulfonic acid residue-introduced amorphous carbon powder was pressure-molded under the same conditions as in Examples 1 and 2, to prepare a disk having a thickness of 0.7 mm and a diameter of 10 mm, and depositing platinum on one surface of the disk. Thereafter, proton conductivity was measured by the AC impedance method described above. The proton conductivity was confirmed to be 7 × 10 ⁻² cm ⁻¹ . This result indicates that the sulfonic acid residue-introduced amorphous carbon has proton conductivity comparable to that of Nafion.

(2) Utilization of sulfonic acid group-introduced amorphous carbon produced from glucose as a solid acid After evacuating the above sulfonic acid residue-introduced amorphous carbon powder at 150 ° C. for 1 hour, 0.2 g of argon was used as a catalyst. The mixture was added to a mixed solution of 0.1 mol of acetic acid and 1.0 mol of ethyl alcohol in an atmosphere and stirred at 70 ° C. for 6 hours. As a result, the production rate of ethyl acetate was about 1.3 mmol min ⁻¹ , indicating that this substance functions as a strong solid acid catalyst.
This specification includes the contents described in the specification and / or drawings of the Japanese patent application (Japanese Patent Application No. 2005-259334) which is the basis of the priority of the present application. In addition, all publications, patents and patent applications cited in the present invention are incorporated herein by reference as they are.

Claims (15)

  Amorphous carbon with fluorine atoms and sulfonic acid groups introduced.   The amorphous carbon according to claim 1, wherein the sulfonic acid density is 0.1 to 8 mmol / g. The amorphous carbon according to claim 1 or 2, having a proton conductivity of 0.01 to 10 Scm ^-1 (according to an alternating current impedance method at a temperature of 80 ° C and a humidity of 100%).   The amorphous carbon according to any one of claims 1 to 3, wherein the sulfur content is from 0.3 wt% to 40 wt%, and the fluorine content is from 0.1 wt% to 50 wt%. .   The sulfur content on the surface is 0.01 to 0.2 in terms of the elemental ratio of sulfur to carbon (S / C), and the fluorine content in the surface is the elemental ratio of fluorine to carbon (F / C) in the range of 0.01 to 0.5. Item 5. The amorphous carbon according to any one of Items 1 to 4.   In X-ray photoelectron spectroscopy, at least one S2p photoelectron peak is detected at a binding energy of 165 eV to 175 eV, and at least one F1s photoelectron peak is detected at a binding energy of 675 eV to 695 eV. The amorphous carbon according to any one of 1 to 5.   Amorphous carbon according to any one of claims 1 to 6, wherein at least a diffraction peak of a carbon (002) plane having a half-value width (2θ) of 5 to 30 ° in powder X-ray diffraction is detected.   Amorphous carbon according to any one of claims 1 to 7, obtained by fluorinating amorphous carbon obtained by heat-treating a compound containing carbon in concentrated sulfuric acid or fuming sulfuric acid. The amorphous carbon according to claim 8, wherein the fluorination treatment of the amorphous carbon into which the sulfonic acid group is introduced is to contact F _{2 at} −70 ° C. to 200 ° C. 9.   A solid acid catalyst containing the amorphous carbon according to any one of claims 1 to 9.   A proton conductive material containing the amorphous carbon according to claim 1.   A fluorine atom and a sulfonic acid group are introduced, comprising a step of heat-treating a compound containing carbon in concentrated sulfuric acid or fuming sulfuric acid, and a step of fluorinating amorphous carbon obtained by the step. The method for producing amorphous carbon according to claim 9. The step of fluorinating amorphous carbon having a sulfonic acid group introduced therein is a step of bringing amorphous carbon into which a sulfonic acid group has been introduced into contact with F _{2 at} -70 ° C to 200 ° C. A process for producing amorphous carbon into which a fluorine atom and a sulfonic acid group are introduced.   13. The heat-treated product is washed with water after the step of heat-treating the compound containing carbon in concentrated sulfuric acid or fuming sulfuric acid and before the step of fluorinating amorphous carbon. 14. A process for producing amorphous carbon into which a fluorine atom and a sulfonic acid group are introduced.   After the step of heat-treating the compound containing carbon in concentrated sulfuric acid or fuming sulfuric acid, and before the step of fluorinating amorphous carbon, the heat-treated product is subjected to cation exchange treatment in a basic aqueous solution. The method for producing amorphous carbon into which fluorine atoms and sulfonic acid groups are introduced according to claim 12 or 13, wherein proton exchange treatment is further performed in an acidic aqueous solution, followed by washing with water.

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