WO2014083426A1

WO2014083426A1 - Method for demeshylating or demethoxylating aromatic compound having methoxy group and catalyst used in the method

Info

Publication number: WO2014083426A1
Application number: PCT/IB2013/002933
Authority: WO
Inventors: Nobutaka Honma; Kaya SUEYASU
Original assignee: Toyota Jidosha Kabushiki Kaisha
Priority date: 2012-11-30
Filing date: 2013-11-27
Publication date: 2014-06-05
Also published as: JP2014129331A; WO2014083426A8; MY177570A; JP5817794B2

Abstract

A method for demethylating or demethoxylating an aromatic compound having a methoxy group is performed under presence of a catalyst containing γ-alumina.

Description

METHOD FOR DEMETHYLATING OR DEMETHOXYLATING AROMATIC COMPOUND HAVING METHOXY GROUP AND CATALYST USED IN THE

METHOD BACKGROUND OF THE INVENTION

1. Field of the Invention

[0001] The present invention relates to a method for demethylating or demethoxylating an aromatic compound having a methoxy group and a catalyst used in the method.

2. Description of Related Art

[0002] Aromatic compounds that can be obtained by thermally decomposing or solubilizing substances contained in lignin or lignin-containing materials and by subjecting those to a demethylation or demethoxylation reaction contain many useful substances that can be used as chemicals, monomer raw materials, or the like.

[0003] J. Japan. Petro. Inst, 53(3), 178-183 (2010), Takao Masuda et al. discloses a technique for forming phenol or the like by reforming products that are obtained by solubilizing lignin and mainly contain guaiacol (methoxyphenol), in which a gas flow reactor having a Zr0₂-Al₂0₃-FeO_x catalyst fixed to a fixed bed is used to perform a reaction at 500°C. Further, Science Vol. 332 no. 6028 pp. 439-443 (2011), Alexey G. Sergeevand John F. Hartwig discloses a homogenous nickel-carbene catalyst as a catalyst that breaks the bond to an aromatic C-0 in an aryl ether.

[0004] However, the method uses the catalyst such as the Zr0₂-Al₂0₃-FeO_x catalyst or a nickel-carbene complex that requires much work for fabrication thereof and has a problem that production of the catalysts requires large cost.

[0005] Japanese Patent Application Publication No. 2011-127022 (JP 2011-127022 A) discloses a method for producing an aromatic compound characterized in that a zeolite that carries one or more kinds of metals selected from the group consisting of elements in the seventh to tenth groups on the periodic table is used to perform a heat treatment on lignin that is poorly reactive. Specifically, JP 2011-127022 A discloses that lignin is solubilized and thereafter vaporized to subject it to a gas phase reaction and benzene and toluene are thereby obtained. However, JP 2011-127022 A does not specifically discloses that catechol or phenol is obtained by the method.

[0006] Japanese Patent Application Publication No. 2012-102297 (JP

2012-102297 A) discloses a method for solubilizing lignin by subjecting lignin or lignin-containing materials to a decomposition reaction in a solvent of water and an alcohol and under presence of a solid acid catalyst. The embodiment describes that γ-alumina is used as the solid acid catalyst. However, JP 2012-102297 A does not specifically discloses that the solid acid catalyst has a demethylating or demethoxylating ability and further catechol or phenol is thereby obtained from lignin or the lignin-containing materials.

[0007] Accordingly, a technique is demanded that can produce the above-described industrially useful aromatic compounds in an industrial scale by use of a catalyst that can be easily prepared at low cost.

SUMMARY OF THE INVENTION

[0008] The present invention provides a production method of an aromatic compound demethylated or demethoxylated from an aromatic compound having a methoxy group, particularly a method for producing an aromatic compound demethylated or demethoxylated at a high yield by use of a catalyst that can easily be prepared at low cost, and a catalyst used in the production method.

[0009] The inventors found that γ-alumina has high demethylating and demethoxylating abilities and reached the present invention. Accordingly, a first aspect of the present invention relates to a production method. The production method includes demethylating or demethoxylating an aromatic compound having a methoxy group under presence of a catalyst containing γ-alumina. [0010] The catalyst may further include at least one kind of metal oxide selected from the group consisting of Ag, Zr, and Ni. The catalyst may further include an oxide of Fe. The catalyst may further include acidic silica. A surface of acidic silica may carry γ-alumina. The aromatic compound having a methoxy group may be guaiacol. The aromatic compound may be demethylated or demethoxylated in a liquid phase.

[0011] A second aspect of the present invention relates to a catalyst for demethylating or demethoxylating an aromatic compound having a methoxy group, the catalyst including γ-alumina.

[0012] The catalyst may further include at least one kind of metal oxide selected from the group consisting of Ag, Zr, and Ni. The catalyst may further include an oxide of Fe. The catalyst may further include acidic silica.

[0013] According to the present invention, the aromatic compound having a methoxy group can be demethylated or demethoxylated at a high yield by use of a catalyst that can easily be prepared at low cost.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Features, advantages, and technical and industrial significance of exemplary embodiments of the invention will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein:

FIG. 1 illustrates a device for performing a method according to an embodiment of the present invention by a gas phase reaction;

FIG. 2 illustrates a device for performing the method according to the embodiment of the present invention by a liquid phase reaction;

FIG. 3 indicates conditions of gas phase reactions of examples 1 to 21;

FIG. 4 is a graph representing phenol yields obtained by methods of the examples 1 to 7 and comparative examples 1 and 2;

FIG. 5 is a graph representing phenol yields obtained by methods of the examples 1 and 8 to 10; FIG. 6 is a graph representing the number of products (the number of kinds of products) obtained by the methods of the examples 1 and 8 to 10;

FIG. 7 is a graph representing phenol selectivity obtained by methods of the examples 8 and 11 to 13;

FIG. 8 is a graph representing phenol selectivity obtained by methods of the examples 9 and 14 to 16;

FIG. 9 is a graph representing phenol selectivity obtained by methods of the examples 10 and 17 to 19;

FIG. 10 is a graph representing phenol yields obtained by methods of the examples 20 and 21 ;

FIG. 1 1 is a graph representing yields of aromatic compounds obtained by the methods of the examples 20 and 21 ;

FIG. 12 indicates conditions of gas phase reactions of examples 22 to 28;

FIG. 13 is a graph representing phenol yields obtained by methods of the examples 8 to 10 and 22 to 26; and

FIG. 14 is a graph representing phenol yields obtained by methods of the example 22 and 26 to 28.

DETAILED DESCRIPTION OF EMBODIMENTS

[0015] The inventors found that γ-alumina had high demethylating and demethoxylating abilities, aromatic compounds having a methoxy group were subjected to a demethylation or demethoxylation reaction under presence of a catalyst containing γ-alumina, and demethylated or demethoxylated aromatic compounds were thereby obtained at high yields. Further, the inventors found that a catalyst containing an oxide of at least one kind of metal selected from the group consisting of Ag, Zr, and Ni and acidic silica could provide a catalyst having further higher demethylating and demethoxylation abilities. The catalyst used in an embodiment of the present invention can easily be prepared at low cost. 5

[0016] The aromatic compounds having a methoxy group that are used in a method of the embodiment of the present invention, although not particularly limited, include compounds obtained when lignin is decomposed or solubilized, for example. Specifically, examples of the compounds include guaiacol, anisole, syringol (2, 6-dimethoxyphenol), 2-methoxy-4-methylphenol, isoeugenol, and derivatives thereof. Guaiacol and anisole are preferable among those. Examples of the derivatives include guaiacylglycerol- -guaiacylether. Examples of materials containing lignin include trunk and empty fruit bunch of oil palm, bagasse, rice straw, wheat straw, corn residue (corn stover, corn cob, corn hull), seed coat and shell of Jatropha, and wood chip. Further, an example of a method of solubilizing lignin is a method disclosed in J. Japan. Petro. Inst, 53(3), 178-183 (2010) Takao Masuda et al. A mixture containing guaiacol as a main component can be obtained by the method disclosed in the document. Materials used in the method of the embodiment of the present invention may contain other compounds as long as the materials contain an aromatic compound having at least one kind of methoxy group as a main component.

[0017] Specifically, preferable examples of the aromatic compounds obtained by the method of the embodiment of the present invention include phenol, catechol, cresol, 2-methylcatechol, 4-methylcatechol, pyrogallol, and 3-methoxycatechol.

Although cresol may be any of o-, m-, and p-cresol, o-cresol is preferable.

j

[0018] A catalyst used in the method of the embodiment of the present invention contains γ-alumina. Use of γ-alumina improves the reforming rate of the aromatic compounds having a methoxy group (the reaction rate of the aromatic compounds having a methoxy group) and the selectivity of a target product (the ratio of the target product contained in reaction products). Consequently, the yield of the target product can be improved compared to a conventional catalyst (a Zr0₂-Al₂0₃-FeO_x catalyst or the like). In view of sufficiently obtaining such an effect, the content of γ-alumina to the catalyst is preferably 50 to 100 mass% and more preferably 90 to 100 mass%. As γ-alumina, commercially available active alumina such as active alumina KC-501 and KHS-46 from Sumitomo Chemical Co., Ltd may be used. Although the above content is calculated on „

6

the basis of catalyst raw materials, the content of the component in the obtained catalyst may decrease by 0% to 3% compared to the content calculated on the basis of the catalyst raw materials.

[0019] The catalyst used in the method of the embodiment of the present invention preferably further contains an oxide of at least one kind of metal selected from the group consisting of Ag, Zr, and Ni and more preferably contains an oxide of Ni. Examples of the oxides of Ag, Zr, and Ni may be Ag₂0₃, Zr0₂, and NiO, respectively. Accordingly, the yield of the target product can be improved. In view of sufficiently obtaining such an effect, the mole ratio of the Al atom amount of γ-alumina and the atom amount of the metal is preferably 99.9:0.1 to 98.0:2.0 and more preferably 99.85:0.15 to 99.0: 1.0. Although the mole ratio of the Al atom amount of γ-alumina and the atom amount of the metal is calculated on the basis of catalyst raw materials, in the obtained catalyst, the ratio may preferably be 99.9:0.1 to 98.2: 1.8 and more preferably 99.8:0.2 to 99.2:0.8.

[0020] The catalyst used in the method of the embodiment of the present invention preferably further contains an oxide of Fe. Examples of oxides of iron include FeO, Fe₃0₄, Fe₂0₃, FeOOH, and mixtures thereof. Accordingly, the yield of the target product can be improved. In view of sufficiently obtaining such an effect, the mole ratio of the Al atom amount of γ-alumina and the atom amount of the metal is preferably 99.9:0.1 to 98.0:2.0 and more preferably 99.85:0.15 to 99.0:1.5. Although the mole ratio of the Al atom amount of γ-alumina and the atom amount of the metal is calculated on the basis of the catalyst raw materials, in the obtained catalyst, the ratio may preferably be 99.9:0.1 to 98.2:1.8 and more preferably 99.8:0.2 to 99.2:0.8.

[0021] The catalyst used in the method of the embodiment of the present invention preferably further contains acidic silica. The number of kinds of reaction products that are resulted from reactions can thereby be reduced, and the target product can more efficiently be refined from the reaction products. Further, a solid acid such as acidic silica has H atoms on its surface and can thereby efficiently supply H atoms to a reaction system. It is considered that the reaction rate can thus be improved. In view of sufficiently obtaining such an effect, the mole ratio of the Al atom amount of γ-alumina and the Si atom amount from acidic silica is preferably 97:3 to 60:40 and more preferably 80:20 to 70:30. Further, because acidic silica has a large specific surface area, many reaction points can be secured. Therefore, acidic silica is preferably contained in a form where γ-alumina is carried on a surface of acidic silica. Although the mole ratio of the Al atom amount of γ-alumina and the Si atom amount from acidic silica is calculated on the basis of the catalyst raw materials, in the obtained catalyst, the ratio may preferably be 96:4 to 65:35 and more preferably 80:20 to 75:25.

[0022] The catalyst used in the method of the embodiment of the present invention preferably further contains both of acidic silica and the oxide of Ni in addition to γ-alumina in view of further improving the selectivity of the target product. The content of Ni with respect to the total mole amount 100 mole% of the Al atom amount of γ-alumina and the Si atom amount from acidic silica is preferably 0.1 to 2.0 mole% and more preferably 0.15 to 1.0 mole%. Although the above content is calculated on the basis of the catalyst raw materials, the content of the component in the obtained catalyst may decrease by 0% to 5% compared to the content calculated on the basis of the catalyst raw materials.

[0023] The catalyst used in the method of the embodiment of the present invention can be produced by an impregnation method, an ion-exchange method, or the like.

[0024] The catalyst used in the method of the embodiment of the present invention is preferably obtained by baking in the atmosphere, for example, preferably after the catalyst is dried and ground. The braking temperature is preferably 350°C to 800°C and more preferably 450°C to 600°C. The baking is preferably performed for 1 to 4.5 hours and more preferably performed for 1.5 to 2.5 hours. The baking is performed, and the yield of the target product can thereby be improved. It is preferable to adopt such a condition as above particularly in a case where the demethylation or demethoxylation reaction is performed in a gas phase. [0025] The demethylation and demethoxylation reactions in accordance with the embodiment of the present invention can be performed in a gas or liquid phase.

[0026] It is preferable to perform the demethylation and demethoxylation reactions in the gas phase in view of facilitating separation of the products resulted from the reactions. A gas phase reaction can be performed by use of a device shown in FIG. 1 , for example.

[0027] In a case where the demethylation and demethoxylation reactions are performed in the gas phase, it is preferable to use water or carbon dioxide (particularly supercritical carbon dioxide) and more preferably water as a solvent. Examples of water include normal water, ion-exchange water, and distilled water. Tap water, industrial water, or the like may also be used.

[0028] In the case where the demethylation and demethoxylation reactions are performed in the gas phase, the mass ratio of a raw material (the aromatic compound having a methoxy group) to the solvent is, although not particularly limited, normally 0.1. to 5 and preferably 0.3 to 1 in views of facilitating supply of the raw material to the catalyst by improving fluidity by using a sufficient amount of the solvent and of reducing calories consumed by the solvent from an economical aspect.

[0029] In the case where the demethylation and demethoxylation reactions are performed in the gas phase, the mass ratio of the catalyst to the raw material (the aromatic compound having a methoxy group) is, although not particularly limited, normally 1 to 10,000 and preferably 100 to 1000. It is preferable to replace the catalyst when it starts degrading. However, the catalyst may be replaced when its activity reaches 50% of an initial activity from the economical aspect. Further, the catalyst can be used while regeneration of the catalyst is repeated by use of a fluidized bed reactor.

[0030] In the case where the demethylation and demethoxylation reactions are performed in the gas phase, the reaction temperature is, although not particularly limited, normally 350°C to 550°C and preferably 400°C to 500°C.

[0031] In the case where the demethylation and demethoxylation reactions are performed in the gas phase, the reaction time (the contacting time between the raw material and the catalyst) is, although not particularly limited, normally 0.01 to 1 second and preferably 0.1 to 1 second.

[0032] In the case where the demethylation and demethoxylation reactions are performed in the gas phase, the reactions are preferably performed in an atmosphere of an inactive gas such as nitrogen or argon.

[0033] In the case where the demethylation and demethoxylation reactions are performed in the gas phase, the reaction pressure (absolute pressure) is, although not particularly limited, preferably 0.1 (the atmospheric pressure) to 1 MPa. Because conditions are influenced by the solvents and the temperature, more preferable conditions are appropriately set.

[0034] The method of the embodiment of the present invention is preferably performed in the liquid phase because it does not require energy for vaporizing the raw material and is economical. A liquid phase reaction can be performed by use of a device shown in FIG. 2, for example.

[0035] In a case where the demethylation and demethoxylation reactions are performed in the liquid phase, it is preferable to use water, residual water remaining after useful substances are removed from the products resulted from the reactions, a molten salt, and an ionic fluid, and more preferable to use water. Examples of water include normal water, ion-exchange water, and distilled water. Tap water, industrial water, or the like may also be used.

[0036] In the case where the demethylation and demethoxylation reactions are performed in the liquid phase, the mass ratio of the raw material (the aromatic compound having a methoxy group) to the solvent is, although not particularly limited, normally 0.1 to 100 and preferably 1 to 20 in view of securing homogeneity of reactants. The liquid phase reaction can be performed in high concentration slurry.

[0037] In the case where the demethylation and demethoxylation reactions are performed in the liquid phase, the mass ratio of the catalyst to the raw material (the aromatic compound having a methoxy group) is, although not particularly limited, normally 1 to 100 and preferably 1 to 50. [0038] In the case where the demethylation and demethoxylation reactions are performed in the liquid phase, the reaction temperature is, although not particularly limited, normally 300°C to 400°C.

[0039] In the case where the demethylation and demethoxylation reactions are performed in the liquid phase, the reaction time is, although not particularly limited, normally 0.5 to 3 hours and preferably 1 to 2 hours.

[0040] In the case where the demethylation and demethoxylation reactions are performed in the liquid phase, the reactions are preferably performed in an atmosphere of an inactive gas such as nitrogen or argon or in an oxygen containing atmosphere such as the atmosphere.

[0041] In the case where the demethylation and demethoxylation reactions are performed in the liquid phase, the reaction pressure is, although not particularly limited, preferably 5 to 15 MPa. Because conditions are influenced by the solvents and the temperature, more preferable conditions are appropriately set.

[0042] The products obtained by the method of the embodiment of the present invention can be separated and refined from a reaction liquid by a normal method such as column chromatography, recrystallization, or solvent extraction. Further, various means such as elemental analysis, NMR spectrum, IR spectrum, and mass spectrometry are used for identification of the products.

[0043] The aromatic compounds such as catechol and phenol that can be obtained by the method of the embodiment of the present invention can be used as chemicals, monomer raw materials, and the like.

[0044] Hereinafter, the present invention will be described with examples. However, the present invention is not limited to the scope of the examples.

[0045] Examples 1 to 21 and comparative examples 1 and 2

Gas phase reaction

A procedure of the gas phase reaction will hereinafter be described with reference to FIG. 1. In the device shown in FIG. 1 , two bubble traps for trapping the products resulted from the reaction were provided on a downstream side of a reaction tube in which the catalyst was set. Acetone was poured into a bubble trap A, and the product was trapped at zero °C (ice-cooled). A solution of acetone/water = 6 mL/2 mL was poured into a bubble trap B on a further downstream side, whereby the products which could not be caught by the bubble trap A were trapped. Further, an opening through which guaiacol and nitrogen + water vapor were introduced was provided on an upstream side of the reaction tube made of quartz.

[0046] Approximately 0.5 g of the catalyst was set in a portion serving as a soaking area of a tube furnace of the device set as described above. Nitrogen and water vapor were allowed to flow from the upstream side for 30 minutes, and a gas atmosphere in the reaction tube was adjusted (nitrogen flow rate 100 cc/minute, saturated vapor amount 22.5 g/m ). The tube furnace was next set to 500°C, and it was confirmed that the temperature of the catalyst reached 500°C by a thermocouple (not shown).

[0047] In a state where nitrogen and water vapor were allowed to flow, guaiacol that was the raw material was brought into direct contact with the catalyst by a canaliculus to start the reaction.

[0048] The gas flow was stopped five minutes later, and the reaction products trapped in the two traps were analyzed by gas chromatography (FID-GC [Shimadzu Corporation, FID-GC 2010plus], DB-17MS column [Agilent Technologies, Inc.]).

[0049] Liquid phase reaction

The liquid phase reaction was performed by use of an autoclave made of stainless used steel (SUS) as shown in FIG. 2 in the following process. Prescribed amounts of guaiacol, water, and the catalyst were put in the autoclave in this order, and the temperature was raised while they were stirred at 200 rpm. After a prescribed temperature was maintained for two hours, stirring was stopped, and rapid cooling was performed. During the reaction, the pressure was measured by a pressure gauge attached to the autoclave. The products resulted from the liquid phase reaction were analyzed as follows.

[0050] After the liquid remaining in the autoclave was centrifuged, the supernatant dissolved in acetone was analyzed by gas chromatography (FID-GC [Shimadzu Corporation, FID-GC 2010plus], DB-17MS column [Agilent Technologies, Inc.]). Further, after the autoclave was cooled to an ordinary temperature, a gas in the autoclave was collected by a syringe, and the formed gas was analyzed by gas chromatography (TCD-GC [Shimadzu Corporation, TCD-GC 2010plus], FID-GC [Shimadzu Corporation, FID-GC 2010plus]).

[0051] [Example 1] A catalyst obtained by baking active alumina KC-501 from Sumitomo Chemical Co., Ltd. (obtained from SUMIKA ALCHEM CO., LTD.) at 400°C for two hours was used to perform the gas phase reaction in a condition indicated in FIG. 3.

[0052] [Example 2] Active alumina KC-501 from Sumitomo Chemical Co.,

Ltd. (obtained from SUMIKA ALCHEM CO., LTD.) was made carry silver in a method described below.

[0053] Active alumina KC-501 (approximately ten grams) was added to 150 to 200 cc of ion-exchange water poured in a 500 cc beaker. The obtained solution was stirred at 200 rpm at a room temperature for approximately ten minutes.

[0054] Silver nitrate (NACALAI TESQUE, INC.) in an amount that provided a ratio of Al atom amount of active alumina KC-501 : Ag atom amount = 99:1 (mol) was added to the obtained solution, and the solution was stirred at 200 rpm at the room temperature for approximately ten minutes.

[0055] Thereafter, a hot stirrer set to 80°C was used to stir the solution until water was vaporized, and drying was then performed by a 120°C dryer (air atmosphere) for a day.

[0056] The obtained powder was ground by an agate mortar for approximately five minutes, and the ground powder was baked by a 400°C electric furnace (air atmosphere) for two hours. Further, the obtained powder was ground by the agate mortar for approximately five minutes to obtain the catalyst. The obtained catalyst was used to perform the gas phase reaction in a condition indicated in FIG. 3.

[0057] [Example 3] A catalyst was obtained in the same manner as the example 2 except that copper (II) oxide (NACALAI TESQUE, INC.) in an amount that provided a ratio of Al atom amount of active alumina KC-501 : Cu atom amount = 99:1 (mol) was used instead of silver nitrate. The obtained catalyst was used to perform the gas phase reaction in a condition indicated in FIG. 3.

[0058] [Example 4] A catalyst was obtained in the same manner as the example 2 except that zirconium oxychloride (NACALAI TESQUE, INC.) in an amount that provided a ratio of Al atom amount of active alumina KC-501 : Zr atom amount = 99:1 (mol) was used instead of silver nitrate. The obtained catalyst was used to perform the gas phase reaction in a condition indicated in FIG. 3.

[0059] [Example 5] A catalyst was obtained in the same manner as the example 2 except that nickel nitrate (NACALAI TESQUE, INC.) in an amount that provided a ratio of Al atom amount of active alumina KC-501 : Ni atom amount = 99.85:0.15 (mol) was used instead of silver nitrate. The obtained catalyst was used to perform the gas phase reaction in a condition indicated in FIG. 3.

[0060] [Example 6] A catalyst was obtained in the same manner as the example 2 except that nickel nitrate (NACALAI TESQUE, INC.) in an amount that provided a ratio of Al atom amount of active alumina KC-501 : Ni atom amount = 99.30:0.70 (mol) was used instead of silver nitrate. The obtained catalyst was used to perform the gas phase reaction in a condition indicated in FIG. 3.

[0061] [Example 7] A catalyst was obtained in the same manner as the example 2 except that nickel nitrate (NACALAI TESQUE, INC.) in an amount that provided a ratio of Al atom amount of active alumina KC-501 : Ni atom amount = 99:1 (mol) was used instead of silver nitrate. The obtained catalyst was used to perform the gas phase reaction in a condition indicated in FIG. 3.

[0062] [Example 8] Acidic silica [Rhodia Japan Ltd.] (approximately 0.5 g) was added to 150 to 200 cc of ion-exchange water poured in the 500 cc beaker, and stirring was performed at 200 rpm at the room temperature for approximately ten minutes.

[0063] Further, aluminum nitrate nonahydrate (NACALAI TESQUE, INC.) in an amount that provided a ratio of Al atom amount of aluminum nitrate : Si atom amount = 95:5 (mol) was added, and stirring was performed at 200 rpm at the room temperature for approximately ten minutes.

[0064] Thereafter, the hot stirrer set to 60°C was used to stir a solution by a low speed rotation until water was vaporized, and drying was then performed by the 120°C dryer (air atmosphere) for a day.

[0065] The obtained powder was ground by the agate mortar for approximately five minutes, and the ground powder was baked by the 700°C electric furnace (air atmosphere) for four hours. Further, the obtained powder was ground by the agate mortar for approximately five minutes to obtain the catalyst.

[0066] A temperature-programmed desorption (TPD) measurement device was used to allow ammonia serving as basic probe molecules to be adsorbed on an acidic silica carrier (Si0₂), the temperature of the catalyst was raised to 100°C to 550°C, and acidic silica having an acidic property such that 0.65 mmol/g of ammonia was desorbed per the weight of the acidic silica carrier in the temperature range was used as acidic silica. The obtained catalyst was used to perform the gas phase reaction in a condition indicated in FIG. 3.

[0067] [Example 9] A catalyst was obtained in the same manner as the example 8 except that acidic silica and aluminum nitrate nonahydrate in amounts that provided a ratio of Al atom amount of aluminum nitrate : Si atom amount = 90:10 (mol) were used. The obtained catalyst was used to perform the gas phase reaction in a condition indicated in FIG. 3.

[0068] [Example 10] A catalyst was obtained in the same manner as the example 8 except that acidic silica and aluminum nitrate nonahydrate in amounts that provided a ratio of Al atom amount of aluminum nitrate : Si atom amount = 80:20 (mol) were used. The obtained catalyst was used to perform the gas phase reaction in a condition indicated in FIG. 3.

[0069] [Example 11] One gram of the catalyst obtained in the example 8 was put in 150 to 200 cc of ion-exchange water, and stirring was performed at 200 rpm at the room temperature for approximately ten minutes. [0070] Further, nickel (II) nitrate hexahydrate (NACALAI TESQUE, INC.) in an amount that provided a ratio of Al atom amount of aluminum nitrate : Si atom amount : Ni atom amount = 95:5:0.15 (mol) was added, and stirring was performed at 200 rpm at the room temperature for approximately ten minutes.

[0071] Thereafter, the hot stirrer set to 80°C was used to stir the solution until water was vaporized, and drying was then performed by the 120°C dryer (air atmosphere) for a day.

[0072] The obtained powder was ground by the agate mortar for approximately five minutes, and the ground powder was baked by the 400°C electric furnace (air atmosphere) for two hours. Further, the obtained powder was cooled to the room temperature, and the obtained powder was thereafter ground by the agate mortar for approximately five minutes to obtain the catalyst. The obtained catalyst was used to perform the gas phase reaction in a condition indicated in FIG. 3.

[0073] [Example 12] A catalyst was obtained in the same manner as the example 1 1 except that nickel nitrate in an amount that provided a ratio of Al atom amount of aluminum nitrate : Si atom amount : Ni atom amount = 95:5:0.7 (mol) was used. The obtained catalyst was used to perform the gas phase reaction in a condition indicated in FIG. 3.

[0074] [Example 13] A catalyst was obtained in the same manner as the example 1 1 except that nickel nitrate in an amount that provided a ratio of Al atom amount of aluminum nitrate : Si atom amount : Ni atom amount = 95:5:1.0 (mol) was used. The obtained catalyst was used to perform the gas phase reaction in a condition indicated in FIG. 3.

[0075] [Example 14] A catalyst was obtained in the same manner as the example 11 except that nickel nitrate in an amount that provided a ratio of Al atom amount of aluminum nitrate : Si atom amount : Ni atom amount = 90: 10:0.15 (mol) was used. The obtained catalyst was used to perform the gas phase reaction in a condition indicated in FIG. 3. [0076] [Example 15] A catalyst was obtained in the same manner as the example 1 1 except that nickel nitrate in an amount that provided a ratio of Al atom amount of aluminum nitrate : Si atom amount : Ni atom amount = 90:10:0.7 (mol) was used. The obtained catalyst was used to perform the gas phase reaction in a condition indicated in FIG. 3.

[0077] [Example 16] A catalyst was obtained in the same manner as the example 11 except that nickel nitrate in an amount that provided a ratio of Al atom amount of aluminum nitrate : Si atom amount : Ni atom amount = 90:10:1.0 (mol) was used. The obtained catalyst was used to perform the gas phase reaction in a condition indicated in FIG. 3.

[0078] [Example 17] A catalyst was obtained in the same manner as the example 1 1 except that nickel nitrate in an amount that provided a ratio of Al atom amount of aluminum nitrate : Si atom amount : Ni atom amount = 80:20:0.15 (mol) was used. The obtained catalyst was used to perform the gas phase reaction in a condition indicated in FIG. 3.

[0079] [Example 18] A catalyst was obtained in the same manner as the example 1 1 except that nickel nitrate in an amount that provided a ratio of Al atom amount of aluminum nitrate : Si atom amount : Ni atom amount = 80:20:0.7 (mol) was used. The obtained catalyst was used to perform the gas phase reaction in a condition indicated in FIG. 3.

[0080] [Example 19] A catalyst was obtained in the same manner as the example 11 except that nickel nitrate in an amount that provided a ratio of Al atom amount of aluminum nitrate : Si atom amount : Ni atom amount = 80:20:1.0 (mol) was used. The obtained catalyst was used to perform the gas phase reaction in a condition indicated in FIG. 3.

[0081] [Example 20] A catalyst obtained by baking active alumina KC-501 from Sumitomo Chemical Co., Ltd. (obtained from SUMIKA ALCHEM CO., LTD.) at 400°C for two hours was used to perform the liquid phase reaction in a condition indicated in FIG. 3. The capacity of an autoclave was 40 mL. [0082] [Example 21] A catalyst obtained by baking active alumina KC-501 from Sumitomo Chemical Co., Ltd. (obtained from SUMI A ALCHEM CO., LTD.) at 400°C for two hours was used to perform the liquid phase reaction in a condition indicated in FIG. 3. The capacity of an autoclave was 200 mL.

[0083] [Comparative example 1] The gas phase reaction was performed in a condition indicated in FIG. 3without using the catalyst.

[0084] [Comparative example 2] An iron-aluminum-zirconia-based catalyst was synthesized as described below with reference to a method disclosed in J. Japan. Petro. Inst, 53(3), 1.78-183 (2010).

[0085] Fe(N0₃)₃-9H₂0 (226.2 g), A1(N0₃)₃-9H₂0 (52.5 g), and ZrOCl₂-8H₂0

(1 1.3 g) were all added in this order and dissolved in 1.5 L of distilled water that was being stirred in a Teflon beaker, and the solution was stirred for approximately two hours. While the obtained solution was stirred, 48,7% NaOH solution (300 g) was dropped thereto at 320 μΐνιηίηυίε, and the solutions were coprecipitated. After the dropping was completed, stirring was continued for a day.

[0086] Rinsing with hot water at 70°C to 80°C was performed until the pH became 7 to 8, solid-liquid separation was thereafter performed, and the obtained cake-like solid was dried at 120°C for a day. The dried solid was ground by the agate mortar and then baked at 700°C for four hours.

[0087] The obtained catalyst was used to perform the gas phase reaction in a condition indicated in FIG. 3. The reaction conditions and results of the examples 1 to 21 and the comparative examples 1 and 2 are indicated in FIG. 3.

[0088] According to FIG. 4, it can be understood that a phenol yield was improved in a case where γ-alumina was used (example 1) compared to cases where no catalyst was used (comparative example 1) and a conventional Fe-based catalyst was used (comparative example 2). Further, in cases where the catalysts containing the oxides of Ag, Zr, Ni were used (examples 2 and 4 to 7), the phenol yield was remarkably improved compared to the case where γ-alumina was used alone (example 1). [0089] According to FIGs. 5 and 6, it can be understood that the phenol yield was improved in cases where acidic silica was carried by γ-alumina (examples 8 to 10) compared to the case where γ-alumina was used alone (example 1). In addition, it can be understood that the number of kinds of products (the number of products that can be detected as peaks of 0.002% or larger that is a detection limit of gas chromatography) decreased.

[0090] According to FIGs. 7 and 8, it can be understood that phenol selectivity was improved in cases where the catalysts containing γ-alumina, acidic silica, and further the oxide of Ni were used (examples 11 to 13, 14 to 16) compared to cases where the catalysts did not contain the oxides of Ni (examples 8 and 9). Activity was most improved when Ni was 1.0% in cases where 5% or 10% acidic silica was carried. Meanwhile, as shown in FIG. 9, activity on phenol selectivity was most improved when Ni was 0.15% in cases where 20% acidic silica was carried. It is considered because catalytic activity excessively increased when much Ni was present and formed phenol further changed to other compounds.

[0091] In cases where γ-alumina was used to perform the liquid phase reaction, the phenol yield was remarkably improved (FIG. 10) at a reaction temperature of 350°C (example 20), and yields of aromatic compounds containing catechol as a main component was remarkably improved (FIG. 1 1) at a reaction temperature of 300°C (example 21).

[0092] Examples 22 to 28

Gas phase reaction

[Example 22] Acidic silica [Rhodia Japan Ltd.] (approximately 0.5 g) was added to 150 to 200 cc of ion-exchange water poured in the 500 cc beaker, and stirring was performed at 200 rpm at the room temperature for approximately ten minutes.

[0093] Aluminum nitrate nonahydrate (NACALAI TESQUE, INC.) in an amount that provided a ratio of Al atom amount of aluminum nitrate : Si atom amount = 70:30 (mol) was added to the^obtained solution, and the solution was stirred at 200 rpm at the room temperature for approximately ten minutes. [0094] Thereafter, the hot stirrer set to 60°C was used to stir the solution by a low speed rotation until water was vaporized, and drying was then performed by the 120°C dryer (air atmosphere) for a day.

[0095] The obtained powder was ground by the agate mortar for approximately five minutes, and the ground powder was baked by the 400°C electric furnace (air atmosphere) for four hours. Further, the obtained powder was ground by the agate mortar for approximately five minutes to obtain the catalyst.

[0096] The temperature-programmed desorption (TPD) measurement device was used to allow ammonia serving as basic probe molecules to be adsorbed on the acidic silica carrier (Si0₂), the temperature of the catalyst was raised to 100°C to 550°C, and acidic silica having an acidic property such that 0.65 mmol/g of ammonia was desorbed per the weight of the acidic silica carrier in the temperature range was used as acidic silica. The obtained catalyst was used to perform the gas phase reaction in a condition indicated in FIG. 12.

[0097] [Example 23] One gram of the catalyst obtained in the example 8 was put in 150 to 200 cc of ion-exchange water, and stirring was performed at 200 rpm at the room temperature for approximately ten minutes.

[0098] Iron (III) nitrate nonahydrate (NACALAI TESQUE, INC.) in an amount that provided a ratio of Al atom amount of aluminum nitrate : Si atom amount : Fe atom amount = 95:5:1 (mol) was added to the obtained solution, and the solution was stirred at

200 rpm at the room temperature for approximately ten minutes.

[0099] Thereafter, the hot stirrer set to 80°C was used to stir the solution until water was vaporized, and drying was then performed by the 120°C dryer (air atmosphere) for a day.

[0100] The obtained powder was ground by the agate mortar for five minutes, and the ground powder was baked by the 400°C electric furnace (air atmosphere) for two hours. Further, the obtained powder was cooled to the room temperature, and the obtained powder was thereafter ground by the agate mortar for approximately five minutes to obtain the catalyst. The obtained catalyst was used to perform the gas phase reaction in a condition indicated in FIG. 12.

[0101] [Example 24] A catalyst was obtained in the same manner as the example 23 except a ratio of Al atom amount of aluminum nitrate : Si atom amount : Fe atom amount = 90:10:1 (mol). The obtained catalyst was used to perform the gas phase reaction in a condition indicated in FIG. 12.

[0102] [Example 25] A catalyst was obtained in the same manner as the example 23 except a ratio of Al atom amount of aluminum nitrate : Si atom amount : Fe atom amount = 80:20:1 (mol). The obtained catalyst was used to perform the gas phase reaction in a condition indicated in FIG. 12.

[0103] [Example 26] A catalyst was obtained in the same manner as the example 23 except a ratio of Al atom amount of aluminum nitrate : Si atom amount : Fe atom amount = 70:30:1 (mol). The obtained catalyst was used to perform the gas phase reaction in a condition indicated in FIG. 12.

[0104] [Example 27] A catalyst was obtained in the same manner as the example 23 except a ratio of Al atom amount of aluminum nitrate : Si atom amount : Fe atom amount = 70:30:1 (mol) and baking at 700°C. The obtained catalyst was used to perform the gas phase reaction in a condition indicated in FIG. 12.

[0105] [Example 28] A catalyst was obtained in the same manner as the example 23 except a ratio of Al atom amount of aluminum nitrate : Si atom amount : Fe atom amount = 70:30:1 (mol) and baking at 400°C .

[0106] The obtained catalyst was used to perform the gas phase reaction in a condition indicated in FIG. 12.

[0107] The reaction conditions and results are indicated in FIG. 12.

[0108] According to FIG. 13, it can be understood that the phenol yield was improved in cases where the catalysts containing γ-alumina, acidic silica, and further the oxide of Fe were used (examples 23 to 26) compared to the corresponding catalysts that did not contain the oxide of Fe (examples 8 to 10 and 22). [0109] According to FIG. 14, the phenol yield was most improved in cases where 30% acidic silica was carried (examples 26 to 28) and baking was performed at 500°C. It is considered because the iron oxide was sufficiently activated and reduction in the activity due to crushed pores on surfaces of γ-alumina and acidic silica did not occur when baking was performed at 500°C.

[0110] The method of the embodiment of the present invention can easily be performed at low cost and can thus preferably be applied to production of the aromatic compounds such as catechol and phenol that are useful chemical substances from lignin in an industrial scale.

Claims

1. A method for demethylating or demethoxylating an aromatic compound having a methoxy group, comprising:

demethylating or demethoxylating the aromatic compound having the methoxy group under presence of a catalyst containing γ-alumina.

2. The method according to claim 1,

wherein the catalyst further includes at least one kind of metal oxide selected from the group consisting of Ag, Zr, and Ni.

3. The method according to claim 1 or 2,

wherein the catalyst further includes an oxide of Fe.

4. The method according to any one of claims 1 to 3,

wherein the catalyst further includes acidic silica.

5. The method according to claim 4,

wherein γ-alumina is carried on a surface of acidic silica.

6. The method according to any one of claims 1 to 5,

wherein the aromatic compound having the methoxy group is guaiacol.

7. The method according to any one of claims 1 to 6,

wherein the aromatic compound is demethylated or demethoxylated in a liquid phase.

8. A catalyst for demethylating or demethoxylating an aromatic compound having a methoxy group, comprising γ-alumina.

9. The catalyst according to claim 8,

10. The catalyst according to claim 8 or 9, further comprising

an oxide of Fe.

1 1. The catalyst according to any one of claims 8 to 10, further comprising

acidic silica.