JP4612507B2 - Catalyst material - Google Patents

Description

  The present invention relates to a catalyst material mainly used for deodorization, and more particularly to a low-temperature deodorization catalyst material that exhibits a deodorization function at a lower temperature than in the past.

Catalytic materials, especially deodorizing catalytic materials, are widely used in household electrical equipment, and examples include air purifiers, hot water cleaning toilet seats, and garbage disposal machines. Examples of the gas to be deodorized include ammonia (NH ₃ ), methyl disulfide ((CH ₃ ) ₂ S ₂ ), methyl mercaptan (CH ₃ SH), hydrogen sulfide (H ₂ S), and the like.

As catalyst materials for deodorizing these gases, conventionally, porous silica (Si oxide) support, porous silica / titania composite (Si, Ti composite oxide) support, porous alumina support, Pt ( Platinum, Au (gold) and other precious metal catalysts are used. Such deodorizing catalyst materials have the effect of oxidizing the gas to be deodorized to odorless substances by the oxidation action of the precious metal catalysts. is doing. In addition, as a method for producing such a deodorizing catalyst material, for example, when platinum is used as a noble metal catalyst, platinum chloride or the like is made into an aqueous solution, and the carrier is immersed in the platinum chloride in the pores of the carrier. In general, a production method in which a platinum-supported catalyst is obtained by impregnating a complex ion and drying and then reducing the aqueous solution, that is, an impregnation method is used (see, for example, Patent Document 1). .)
Japanese Patent Laid-Open No. 10-296087

  However, in order to actually incorporate the deodorizing catalyst material produced as described above into an electric device to exhibit the deodorizing function, it is usually necessary to heat the catalyst material to about 250 ° C. Even if the temperature is lower than this temperature, the catalyst acts as a temporary catalyst, but since the activity is low, sufficient oxidation does not occur with respect to the supplied gas, and malodorous gas remains as it is. Therefore, in the past, the catalyst material was heated to increase its activity. However, if the temperature at which the catalyst function can be fully exerted can be lowered than before, the heater power for heating can be reduced. This can reduce the power consumption of the electric device. That is, in recent years, it is expected that a catalyst material having higher activity and capable of realizing an oxidation reaction at a low temperature (particularly near room temperature) is expected.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a catalyst material capable of obtaining high catalytic activity at a lower temperature than in the past.

  The catalyst material according to claim 1 of the present invention includes a silicon alkoxide, one or more metal compounds including at least one element selected from Group 5 to 11 of the periodic table, and 2, 4, 12, and 13 of the periodic table. After mixing one or more kinds of metal compounds containing at least one element selected from the group and a nonionic surfactant, the silicon alkoxide is polymerized and then heated in an oxidizing atmosphere, and then the silica component is removed. It is characterized by comprising.

  The invention of claim 2 is characterized in that, in claim 1, the silicon alkoxide is selected from the following formulas (1) and (2).

  A third aspect of the invention is characterized in that, in the first or second aspect, a block copolymer of ethylene oxide and propylene oxide is used as the nonionic surfactant.

  The invention of claim 4 is the metal compound containing at least one element selected from groups 5 to 11 of the periodic table according to any one of claims 1 to 3, wherein V, Cr, Mn, Fe, Co, Ni, Cu It is characterized by using an element containing an element selected from.

  The invention of claim 5 is the metal compound containing at least one element selected from groups 2, 4, 12, and 13 of the periodic table according to any one of claims 1 to 4, wherein Mg, Ti, Zr, Zn, Al It is characterized by using an element containing an element selected from.

  A sixth aspect of the invention is characterized in that, in any one of the first to fifth aspects, the removal of the silica component is performed by supplying an alkali.

  The invention of claim 7 uses any one of claims 1 to 6, wherein the metal compound containing Mn is used as the metal compound containing at least one element selected from groups 5 to 11 of the periodic table, As a metal compound containing at least one element selected from Group 4, 12, and 13, a compound containing Ti is used.

  According to the catalyst material according to claim 1 of the present invention, it is possible to obtain high catalytic activity at a lower temperature than in the past. In addition, a metal compound containing at least one element selected from Group 5 to 11 of the periodic table is used as a catalyst active component, and at least 1 selected from Groups 2, 4, 12, and 13 of the periodic table is used as a catalyst carrier. Since a metal compound containing two elements is used, there is no need to use a noble metal as in the prior art, and the catalyst material can be manufactured at low cost from the viewpoint of raw material costs.

  According to the invention of claim 2, a porous silica skeleton can be easily formed by incorporating an alkyl group into a surfactant micelle rather than using tetraethoxysilane, tetramethoxysilane or the like. is there.

  According to invention of Claim 3, the alkyl group of a silicon alkoxide becomes easy to be taken in in a surfactant micelle, As a result, a porous silica frame | skeleton can be formed easily.

  According to the invention of claim 4, higher catalytic activity can be obtained.

  According to the invention of claim 5, the catalytically active component can be supported more firmly.

  According to the invention of claim 6, since the catalytically active component maintains a high surface area and is supported on the catalyst carrier at a high concentration in this state, higher catalytic activity can be obtained.

  According to the seventh aspect of the invention, the catalytic activity can be increased and the catalytically active component can be more firmly supported.

  Embodiments of the present invention will be described below.

  In the present invention, the silicon alkoxide is not particularly limited, but is preferably selected from the following formulas (1) and (2).

  Specific examples of the silicon alkoxide represented by the above formula (1) include octadecyltrimethoxysilane, octadecyltriethoxysilane, hexadecyltrimethoxysilane, hexadecyltriethoxysilane, and the like. Specific examples of the silicon alkoxide represented by) include diisobutyldimethoxysilane and diethoxymethyloctadecylsilane. Thus, when using a silicon alkoxide having a long-chain alkyl group (R1, R3, R4), a surfactant micelle described later is used rather than using tetraethoxysilane or tetramethoxysilane having a short-chain alkyl group. By incorporating an alkyl group therein, a porous silica skeleton can be easily formed.

Further, the nonionic surfactant is not particularly limited, but a block copolymer of ethylene oxide and propylene oxide is preferably used. Specific examples thereof include “P123” manufactured by BASF [(HO (CH ₂ CH ₂ O) ₂₀ (CH ₂ CH (CH ₃ ) O) ₇₀ (CH ₂ CH ₂ O) ₂₀ ) H], Asahi Denka Kogyo ( Ltd.) "P85" _{[(HO (CH 2 CH 2 O} ) 26 (CH 2 CH (CH 3) O) 39 (CH 2 CH 2 O) 26) H ], manufactured by Asahi Denka Co., Ltd. "P103" may be mentioned _{[(HO (CH 2 CH 2 O} ) 17 (CH 2 CH (CH 3) O) 55 (CH 2 CH 2 O) 17) H ] and the like. When such a block copolymer is used, the alkyl group of silicon alkoxide is easily incorporated into the surfactant micelle, and as a result, a porous silica skeleton can be easily formed.

  Further, a metal compound containing at least one element selected from Group 5 to 11 of the periodic table (hereinafter also referred to as “metal compound containing Group 5 to 11 element of the periodic table”) is a material used as a catalytically active component. Such metal compounds are not particularly limited, but those containing an element selected from V, Cr, Mn, Fe, Co, Ni, and Cu are preferably used. Specifically, as a metal compound containing V, vanadium (III) chloride and the like, and as a metal compound containing Cr, chromium (II) chloride, chromium (III) hexahydrate, chromium nitrate (III), chromium acetate As a metal compound containing Mn, such as (III), manganese chloride (II), manganese nitrate (II) hexahydrate, manganese acetate (II) tetrahydrate, etc., as a metal compound containing Fe, iron chloride (II ) As a metal compound containing Co, such as tetrahydrate, iron chloride (III), iron nitrate (III) nonahydrate, iron hydroxide (III), iron phosphate (III), cobalt (II) chloride, As metal compounds containing Ni, such as cobalt nitrate (II) hexahydrate, nickel (II) chloride, nickel (II) chloride hexahydrate, nickel (II) nitrate hexahydrate, nickel acetate (II) tetra As metal compounds containing Cu, such as hydrates, copper chloride (II), copper nitrate (II And copper (II) acetate monohydrate, may be exemplified. When such a metal compound is used, higher catalytic activity can be obtained. In addition, at least one kind of metal compound containing an element of Group 5 to 11 in the periodic table is used.

  Further, a metal compound containing at least one element selected from Groups 2, 4, 12, and 13 of the periodic table (hereinafter also referred to as “metal compound containing elements of Groups 2, 4, 12, and 13 of the periodic table”). , A material used as a catalyst carrier carrying the catalytically active component, and exists as an oxide in the catalyst material. Such a metal compound is not particularly limited, but a metal compound containing an element selected from Mg, Ti, Zr, Zn, and Al is preferably used. Specifically, as a metal compound containing Mg, magnesium ethoxide, magnesium methoxide, magnesium propoxide, magnesium chloride, magnesium nitrate hexahydrate, magnesium acetate tetrahydrate, etc., as a metal compound containing Ti, titanium Metallic compounds containing Zr such as methoxide, titanium ethoxide, titanium isopropoxide, titanium tetrabutoxide, titanium tetrachloride, titanium nitrate, zirconium butoxide, zirconium ethoxide, zirconium isopropoxide, zirconium chloride, zirconium hydroxide, etc. As a metal compound containing Al, such as zinc propoxide, zinc chloride, zinc nitrate hexahydrate, zinc acetate dihydrate, etc., as a metal compound containing Al, aluminum butoxide, aluminum ethoxide, aluminum iso Ropokishido, aluminum chloride hexahydrate, aluminum nitrate nonahydrate, and aluminum acetate, can be exemplified. When such a metal compound is used, the catalytically active component can be more firmly supported. In addition, at least one kind of metal compound containing elements of Groups 2, 4, 12, and 13 of the periodic table is used.

  Here, the combination of the metal compound containing the Group 5-11 element of the periodic table and the metal compound containing the Group 2, 4, 12, 13 element of the periodic table is not particularly limited, As a metal compound containing a group 5-11 element of the periodic table, a compound containing Mn is used, and as a metal compound containing a group 2, 4, 12, 13 element of the periodic table, a compound containing Ti is used. Is preferred. With such a combination, it is possible to obtain a higher catalytic activity and to support the catalytically active component more firmly.

  And in this invention, a catalyst material can be manufactured as follows.

  First, silicon alkoxide, one or more metal compounds including at least one element selected from Groups 5 to 11 of the periodic table, and at least one element selected from Groups 2, 4, 12, and 13 of the periodic table are included. A dispersion liquid is prepared by mixing one or more kinds of metal compounds and a nonionic surfactant. The process of preparing this dispersion will be described in more detail. First, a nonionic surfactant and an organic solvent such as isopropanol are mixed and stirred. At this time, the molar ratio of the surfactant to the organic solvent can be set to 0.01: 45 to 0.1: 45. Next, silicon alkoxide is added to the mixed solution and mixed. At this time, the molar ratio of the surfactant to the silicon alkoxide in the mixed solution can be set to 0.01: 1 to 0.1: 1. Next, one or more types of metal compounds containing at least one element selected from Group 5 to 11 of the periodic table are added to and mixed with this mixed solution. At this time, the molar ratio between the silicon alkoxide and the metal compound containing a group 5-11 element in the periodic table can be set to 1: 0.2 to 1: 5. Furthermore, one or more kinds of metal compounds containing at least one element selected from Groups 2, 4, 12, and 13 of the periodic table and an acid such as hydrochloric acid are added to the mixed solution and mixed. At this time, the molar ratio between the silicon alkoxide and the metal compound containing the elements of Groups 2, 4, 12, and 13 of the periodic table can be set to 1: 1 to 1:15. The molar ratio of the organic solvent to the acid can be set to 45: 1 to 45:10. Thus, the molar ratio of Si, Group 5 to 11 elements of the periodic table, and Group 2, 4, 12, and 13 elements of the periodic table is 1: 0.2: 1 to 1: 5: 15. It can be set and blended.

  Thereafter, the silicon alkoxide in the dispersion is polymerized by aging, and then the dispersion is heated in an oxidizing atmosphere. Here, the oxidizing atmosphere refers to an atmosphere in which oxygen or air exists, and heating in such an atmosphere is performed using an electric furnace capable of entering and exiting oxygen or air, or oxygen or air. It can be performed by heating while actively circulating air. This heating includes pre-baking and baking, and it is considered that the silicon alkoxide is polymerized during this heating.

  Specifically, the dispersion is aged at room temperature to 80 ° C. for 1 day to 8 weeks, and then pre-baked at 80 to 600 ° C. for 2 to 10 hours, and then 600 to Firing is performed at 1000 ° C. for 2 to 10 hours. In this step, a part of the metal compound becomes a metal oxide.

In the process of polymerizing the silicon alkoxide in the dispersion in this way, the surfactant molecules form micelles, and the crosslinking of the crosslinkable substance, that is, the skeleton formation, proceeds using the micelles as templates. Here, the crosslinkable substance means the above-mentioned silicon alkoxide, a metal compound containing a group 5-11 element of the periodic table, and a metal compound containing a group 2, 4, 12, 13 element of the periodic table, In particular, in the case of a metal compound containing elements of Groups 2, 4, 12, and 13 of the periodic table, the metal in the metal compound forms a hydroxide, and the hydroxide is crosslinked by a surfactant. Conceivable. The micelles are regularly arranged, and after drying, a porous structure that is a composite oxide can be obtained. The metal species and metal oxide species of the metal compound are supported in a highly dispersed state on the surface of the porous structure and inside the skeleton. Note that not all metal compounds are cross-linked, but silicon alkoxide is taken into the cross-linked SiO ₂ and removed together when silica is removed in a later step.

  And the catalyst material 1 as shown in FIG. 1 can be obtained by removing the silica component in complex oxide. Here, the silica component is removed for the following reason. That is, with the polymerization of silicon alkoxide, a porous structure is formed by a metal oxide containing elements of Groups 2, 4, 12, and 13 of the periodic table, and the periodic table is formed in the pores of the porous structure. The metal oxide containing the elements of Group 5 to 11 is fixed as a catalytic active component over a wide area, but since this fixed catalytic active component is covered with a silica component, the original catalytic activity is obtained. I can't. Therefore, it is necessary to remove the silica component to expose the catalytically active component fixed in the pores of the porous structure.

  Here, it is preferable to remove the silica component by supplying an alkali. Specifically, an alkali (pH = 10-14) such as an aqueous sodium hydroxide solution is supplied to the composite oxide, and the silica component in the composite oxide is changed under the conditions of 60 to 150 ° C. and 20 to 80 minutes. The silica component can be removed by dissolving in an alkali. In this way, when the silica component is removed by supplying an alkali, the catalytically active component 2 maintains a high surface area and is supported on the catalyst carrier 3 at a high concentration in this state. It can be obtained higher.

  In the catalyst material 1 obtained in this manner, a very dense porous structure is formed by the metal compound containing the elements of Groups 2, 4, 12, and 13 of the periodic table. Since a metal compound containing a group 5-11 element of the periodic table is fixed as a catalytically active component with a large exposed area in the pores of the body, the catalytic activity can be obtained at a lower temperature than before. .

In addition, a metal compound containing a group 5-11 element of the periodic table is used as the catalytic active component 2, and a metal compound containing a group 2, 4, 12, 13 element of the periodic table is used as the catalyst carrier 3. Therefore, there is no need to use a noble metal as in the prior art, and even if noble metal is used, the catalytic activity can be obtained in a smaller amount than in the prior art. It can be manufactured. The average diameter of the pores 4 of the catalyst material 1 is preferably 1 to 40 nm, and the porosity is preferably 30 to 75%. The specific surface area in this case is determined by the BET method (specific surface area measurement method) by nitrogen adsorption, and is 300 to 1300 m ² / g. However, the specific surface area changes if the metal compound used for the production of the catalyst material 1 is different.

  Hereinafter, the present invention will be specifically described by way of examples.

Example 1
1 g of surfactant “P123” (manufactured by BASF) and 10 g of isopropanol (manufactured by Kanto Chemical Co., Inc., for organic synthesis reagents) were mixed and stirred. To this mixed liquid, 1.499 g of octadecyltrimethoxysilane (manufactured by ACROS ORGANICS) was mixed and stirred. To this mixed solution, 0.503 g of manganese (II) chloride (manufactured by Nippon Kojun Chemical Co., Ltd., special grade) was mixed and stirred. Further, 3.41 g of titanium isopropoxide (manufactured by Kanto Chemical Co., Ltd., for organic synthesis reagents) and 0.976 g of hydrochloric acid (manufactured by Kanto Chemical Co., Ltd., special grade) are mixed with this mixed solution and stirred. A dispersion was obtained. At this time, preparation was performed so that Si: Mn: Ti (molar ratio) = 1: 1: 3.

  Thereafter, the dispersion is aged at 40 ° C. for 2 weeks, and then the aged dispersion is heated from room temperature to 450 ° C. at a rate of 10 ° C./min, followed by pre-baking at 450 ° C. for 5 hours. After heating up to 800 ° C. at 1 ° C./min, baking was performed at 800 ° C. for 5 hours.

  The silica component in the composite oxide thus obtained is dissolved in an aqueous sodium hydroxide solution (pH = 13.5) at 100 ° C. for 40 minutes to obtain a catalyst material (catalyst 1). Obtained.

(Example 2)
A catalyst material (catalyst 2) was obtained in the same manner as in Example 1 except that titanium tetrachloride (manufactured by Wako Pure Chemical Industries, Ltd., special grade) was used instead of titanium isopropoxide in Example 1.

(Example 3)
A catalyst material (catalyst 3) was obtained in the same manner as in Example 1 except that copper chloride (II) (manufactured by Nacalai Tesque Co., Ltd., special grade) was used instead of manganese chloride (II) in Example 1. .

Example 4
A catalyst material (catalyst 4) was used in the same manner as in Example 1, except that nickel chloride (II) hexahydrate (manufactured by Nacalai Tesque Co., Ltd., special grade) was used instead of manganese chloride (II) in Example 1. )

(Example 5)
In the same manner as in Example 1 except that “P85” (manufactured by Asahi Denka Kogyo Co., Ltd.) was used instead of the surfactant “P123” (manufactured by BASF) in Example 1, a catalyst material (catalyst 5) Got.

(Example 6)
A catalyst material (catalyst 6) was obtained in the same manner as in Example 1 except that diisobutyldimethoxysilane (manufactured by Degussa) was used instead of octadecyltrimethoxysilane in Example 1.

(Comparative Example 1)
4.85 g of silica (catalyst society reference catalyst “JRC-SIO-8”), 40 g of distilled water, and 3.30 g of dinitrodiamine platinum nitric acid solution (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) (weight of the total catalyst material finally obtained) The amount of the dinitrodiamine platinum nitric acid solution was adjusted so that the weight of platinum was 3 wt%), and the mixture was stirred for 2 hours and allowed to stand for 12 hours. Next, the solution was evaporated to dryness at 40 ° C. and 40 Torr (5.33 kPa). The powder thus obtained was dried for 12 hours at 110 ° C. in an air atmosphere. Then, it is calcined at 400 ° C. for 3 hours in a flow of 150 ml / min of air (10 ° C./min), cooled to 350 ° C. in a flow of 100 ml / min of nitrogen, reduced at 350 ° C. in a flow of 15 ml / min of hydrogen, and 100 ml of nitrogen. The catalyst material (catalyst 7) was obtained by lowering the temperature to room temperature during circulation / min.

(Ammonia conversion)
Using a known fixed bed flow apparatus, 36 mg to 1.2 g of the catalyst material (catalysts 1 to 7) obtained as described above was placed in a glass reaction tube of the apparatus, and air containing 300 ppm of ammonia in the catalyst material. Was aerated at a flow rate of 200 mL / min to measure the ammonia conversion. At this time, the amount of the catalyst material was adjusted so that the space velocity was SV = 330,000 mL · h ⁻¹ · g ⁻¹ (cat). In addition, as a space velocity, the thing per weight of a catalyst active component was used. Specifically, for catalysts 1, 2, 5, and 6, manganese (II) chloride is assumed to be MnO ₂ , for catalyst 3, copper (II) chloride is assumed to be CuO, and for catalyst 4 Assuming that nickel chloride (II) was changed to NiO, the weight of the catalytically active component was calculated for catalyst 7 as Pt. The temperature of the catalyst material was set to 50 ° C. The conversion rate was determined from the ammonia decrease rate, and the ammonia concentration was determined using a gas detector tube. The ammonia conversion rates of the catalysts 1 to 7 are shown in the following [Table 1].

  As seen in the above [Table 1], the ammonia conversion rate of Comparative Example 1 is 2.2%, whereas the ammonia conversion rates of Examples 1 to 6 are all 43.2% or more. According to the present invention, it is confirmed that the catalyst activity can be sufficiently high at a temperature close to room temperature of 50 ° C.

  In addition, Example 3 using a combination of metal compounds containing Mn and Ti rather than Example 3 using a combination of metal compounds containing Cu and Ti and Example 4 using a combination of metal compounds containing Ni and Ti. It is confirmed that 1, 2, 5 and 6 can obtain higher catalytic activity.

  Thus, the catalysts 1 to 6 are particularly promising as ammonia deodorizing catalysts.

It is a perspective view of the catalyst material which shows an example of embodiment of this invention.

Explanation of symbols

1 catalyst material 2 catalyst active component 3 catalyst support 4 pore

Claims (7)

  Silicon alkoxide, one or more metal compounds including at least one element selected from Groups 5 to 11 of the periodic table, and one type including at least one element selected from Groups 2, 4, 12, and 13 of the periodic table A catalyst material obtained by mixing the above metal compound and a nonionic surfactant, polymerizing silicon alkoxide, heating in an oxidizing atmosphere, and then removing the silica component. The catalyst material according to claim 1, wherein the silicon alkoxide is selected from the following formulas (1) and (2).

  The catalyst material according to claim 1 or 2, comprising a block copolymer of ethylene oxide and propylene oxide as the nonionic surfactant.   A metal compound containing at least one element selected from Group 5 to 11 of the periodic table is used which contains an element selected from V, Cr, Mn, Fe, Co, Ni and Cu. Item 4. The catalyst material according to any one of Items 1 to 3.   A metal compound containing at least one element selected from Groups 2, 4, 12, and 13 of the periodic table is used which contains an element selected from Mg, Ti, Zr, Zn, and Al. Item 5. The catalyst material according to any one of Items 1 to 4.   The catalyst material according to any one of claims 1 to 5, wherein the silica component is removed by supplying an alkali. A metal compound containing Mn as a metal compound containing at least one element selected from Groups 5 to 11 of the periodic table and containing at least one element selected from Groups 2, 4, 12, and 13 of the periodic table The catalyst material according to any one of claims 1 to 6, wherein a catalyst material containing Ti is used.

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