JP3663687B2 - Method for supporting metal hydroxide and / or oxide on support - Google Patents

Description

Ｍｗは生成した重合物の重量平均分子量を、
Ｍｎは同じく数平均分子量を示す。
【００２６】
ベンゼンの部分水添
実施例２で調製した酸化ジルコニウム担持シリカ５ｇを１００ｍｌの脱塩水に加えた。次いでこれに塩化ルテニウム及び硝酸亜鉛を溶解し、６０℃で撹拌したのち、６０℃で水を減圧留去した。
得られた乾燥固体をパイレックスガラス管に充填し、水素気流中２００℃で２時間還元して、０．５％Ｒｕ−０．５％Ｚｎ／ＺｒＯ₂ −ＳｉＯ₂ 触媒を得た。
【００２７】
ガラス内筒をセットした５００ｍｌ容のオートクレーブに上記で得た触媒２．０ｇ、硫酸亜鉛・７水和物７．２ｇ、ベンゼン４０ｍｌ及び脱塩水６０ｍｌを仕込み、温度１５０℃、水素分圧５０ｋｇ／ｃｍ² で１時間反応させた。反応終了後、冷却して油相を採取し、ガスクロマトグラフィーで分析したところ、ベンゼン転化率６２％、シクロヘキセン選択率７８％であった。
なお、比較例１で調製した酸化ジルコニウム担持シリカを用いた以外は、上記と全く同様にして還元触媒を調製し、且つこれを用いて上記と全く同様にしてベンゼンの水素化を行なったところ、ベンゼン転化率５２％、シクロヘキセン選択率６４％であった。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for supporting a metal hydroxide and / or metal oxide on a support. In particular, the present invention relates to a method for supporting a metal hydroxide and / or oxide dispersed very finely on a support. The present invention also relates to a method for preparing a metal hydroxide or metal oxide which is useful as an acid-base catalyst and is supported in a very finely dispersed manner on a support.
[0002]
[Prior art]
It is known that a metal oxide functions as an acid-base catalyst depending on its own acid-base strength. It is also well known that when a plurality of metal oxides are combined to form a composite oxide, it is possible to obtain a stronger acid strength than that of a single metal oxide.
As a method for preparing a metal oxide used as an acid-base catalyst, particularly a composite oxide, there is a method in which a metal salt or metal alkoxide is hydrolyzed to form a hydroxide, and then this hydroxide is heated to convert it into an oxide. Commonly used.
[0003]
[Problems to be solved by the invention]
However, it is extremely difficult to support the metal oxide in a finely dispersed state on the support by this method. Moreover, even when a composite oxide is prepared by this method, the acid-base strength and the amount of acid-base are often much lower than theoretically predicted values. The cause is that even when a metal salt or a metal alkoxide is hydrolyzed in a liquid phase, it is difficult to form a hydroxide in which different metals are complexed at an atomic level, and a mixture of hydroxides of the respective metals is likely to be formed. It seems to be due to this. The oxides obtained by heating such hydroxides are naturally separated from the theoretical complex oxides, and are mainly composed of oxides of the respective metals. It seems to be in a state. In the hydrolysis, the reason why the different metals are not complexed at the atomic level is considered to be because the hydrolysis rates are different, but it is extremely difficult to control the hydrolysis rate in the liquid phase. Therefore, in the present invention, instead of performing hydrolysis in a liquid phase, that is, hydrolysis in a state in which the metal salt or metal alkoxide of the raw material and the generated hydroxide can freely move, these movements are constrained. It is intended to provide a method for performing hydrolysis. According to this method, a metal hydroxide or oxide dispersed more finely than the conventional method can be supported on the support, or a complex oxide more complex at the atomic level can be supported. it is conceivable that.
[0004]
[Means for Solving the Problems]
According to the present invention, a metal salt and / or metal alkoxide is supported on a carrier, and then the metal salt and / or metal alkoxide supported in a solid phase is contacted with a basic substance, In addition, by converting the metal alkoxide into the corresponding metal hydroxide and / or metal oxide, the metal hydroxide and / or oxide can be supported on the carrier in a finely dispersed state.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, a basic substance is brought into contact with a metal salt or metal alkoxide supported on a carrier in a solid phase state. As a result, the metal salt or metal alkoxide reacts with water adsorbed on the carrier, coordinated water of the metal salt, water that is not in a liquid phase such as atmospheric moisture, and a basic substance in a solid phase state. Hydrolysis occurs and a metal hydroxide is produced. The produced metal hydroxide is further dehydrated into an oxide depending on the environmental conditions. Further, after the hydrolysis is completed, the hydroxide can be converted into an oxide by heating to a higher temperature. In the present invention, any commonly used carrier such as activated carbon or metal oxide can be used as the carrier. Preferably, a metal oxide is used as the support. For example, oxides such as silica, alumina, titania, zirconia, zinc oxide, magnesia, lanthanum oxide, cerium oxide, niobium oxide, tantalum oxide, composite oxides such as silica-alumina, silica-titania, silica-zirconia, aluminum silicate And metallosilicates in which aluminum of aluminum silicate is isomorphously substituted with iron, titanium, gallium or the like, and zeolites composed thereof (for example, mordenite, faujasite, ferrierite, zeolite Ω, ZSM-5, ZSM-11, zeolite β SSZ-26, SSZ-33, MCM-22, MCM-41, etc.) or clay minerals such as montmorillonite, saponite, sepiolite, mica, etc. are used. When a metal oxide is used as the support, the supported metal hydroxide or oxide is not physically placed on the support, but is chemically bonded to the support metal oxide. In some cases, it is considered that a composite oxide with the metal oxide of the carrier is formed.
[0006]
Metal salts and metal alkoxides to be supported on the carrier (in the following description, for the sake of simplicity unless otherwise specified, metal salts including both metal salts and metal alkoxides are referred to as metal salts) include Group II of the periodic table, III containing rare earths Group, IV, V, VIA, VIIA, VIII, and other metal salts are used. Examples of the salt include nitrate, acetate, oxynitrate, chloride, oxychloride, and examples of the alkoxide include, but are not limited to, methoxide, ethoxide, isopropoxide, butoxide and the like. It is not a thing. Examples of specific metal salts include aluminum nitrate, aluminum acetate, and aluminum isopropoxide for aluminum, gallium nitrate for gallium, zirconium oxynitrate (ZrO (NO ₃ ) ₂ ), zirconium oxychloride ( ZrOCl ₂ ), zirconium butoxide, etc., titanium includes titanium tetrachloride, titanium isopropoxide, titanium butoxide, etc., hafnium includes hafnium oxychloride (HfOCl ₂ ), noble metals include ruthenium chloride, H ₂ PtCl ₅ , palladium acetate, palladium nitrate, etc. can give.
[0007]
The metal salt is preferably uniformly supported on the support. Therefore, usually, a method is used in which the metal salt is dissolved in a solvent to form a solution, the solution is impregnated into the support, and then the solvent is removed.
In the case of a metal salt, it is usually sufficient to impregnate it as an aqueous solution. However, in the case of a metal alkoxide, since hydrolysis occurs, water cannot often be used as a solvent. In such a case, the carrier may be impregnated by dissolving in an alcohol such as methanol or ethanol, or a polar organic solvent such as acetone or dimethylformamide. Further, when a metal salt is hardly soluble in water, it may be dissolved in these organic solvents. When a metal salt or metal alkoxide that is very easily hydrolyzed is supported, the solvent is preferably dehydrated or operated in a dry atmosphere.
[0008]
The amount of the metal salt supported on the carrier is arbitrary, but is usually 0.01 to 50% by weight based on the carrier. According to the present invention, since extremely fine metal hydroxide or metal oxide is finally uniformly dispersed on the carrier, a small amount is often sufficient as compared with the conventional method. Therefore, the present invention is particularly advantageous when supporting an expensive metal.
[0009]
In a preferred embodiment of the present invention, a basic substance precursor that generates a basic substance by pyrolysis is supported on a carrier together with a metal salt. Examples of such a basic substance precursor include urea, alkyl-substituted urea, thiourea, alkyl-substituted thiourea, and organic compounds having both an amino group and a carboxyl group, such as various amino acids. These basic substances are easily decomposed by heating to produce ammonia and amines, and the produced ammonia and amines together with water hydrolyze the metal salt into the corresponding hydroxide. Preferably, by thermal decomposition, ammonia or lower amines, that is, the general formula NR ₁ R ₂ R ₃ (wherein R ₁ , R ₂ and R ₃ each independently represents hydrogen or an alkyl group having 1 to 3 carbon atoms). The basic substance precursor which produces | generates the basic substance represented by this is used. The supported amount of these basic substance precursors is 10 mol of basic substance theoretically generated from the basic substance precursor with respect to 1 mol of hydroxyl group of the metal hydroxide that can theoretically be generated from the metal salt. Range. Of course, it is possible to carry it in a larger amount than 10 moles, but there is no special advantage by using a larger amount. In general, the precursor may be supported so that the basic substance to be generated is 0.1 to 5 mol with respect to 1 mol of the hydroxyl group of the metal hydroxide to be generated. Since the hydrolysis reaction is a catalytic reaction, the hydrolysis reaction proceeds even if the amount of the basic substance to be produced is 1 mol or less per 1 mol of the hydroxyl group of the metal hydroxide to be produced. However, if the amount is too small, the hydrolysis will occur. Unless a basic substance is replenished from the outside, hydrolysis is not sufficiently performed, and it becomes difficult to finally make a fine metal oxide uniformly dispersed on the support.
[0010]
In order to support the metal salt and the basic substance precursor on the carrier, the carrier may be impregnated with a solution containing the metal salt and the basic substance precursor. Care should be taken not to cause hydrolysis when preparing the solution. Alternatively, the support may be impregnated with the metal salt and the basic substance precursor as separate solutions. For example, the carrier is impregnated with an aqueous solution of a metal salt, dried to remove moisture, and then the carrier is impregnated with a solution in which a basic substance precursor is dissolved in an organic solvent that does not dissolve the metal salt. The basic substance precursor can be uniformly supported on the carrier.
[0011]
The metal salt supported on the carrier is then hydrolyzed in the solid phase to the corresponding hydroxide. Here, the solid phase state means that the liquid phase is not substantially present, that is, the metal salt is not in a dissolved state, and does not mean that water is not present at all. Rather, a small amount of water is necessary for the hydrolysis reaction, and a trace amount of water in a non-liquid phase state present in the system, such as adsorbed water of the carrier, coordinated water of the metal salt or water vapor in the atmosphere, is involved. The hydrolysis reaction proceeds. Ammonia or other basic substances that have been sufficiently dehumidified in a substantially completely anhydrous state, for example, those that have been dried in a vacuum or dry inert gas atmosphere for a long time at a temperature of 100 ° C. or higher. Hydrolysis does not occur even when in contact with the substrate, and therefore, metal oxide fine particles are not finally formed. Therefore, it is preferable that the adsorbed water is retained in the carrier or the coordinated water is retained in the supported metal salt. When an oxide is used as a support, 5 to 6 water can be adsorbed per surface hydroxyl group. The metal salt can usually hold 2 to 12 coordination water. Further, 5% or less of water may be present in the atmosphere.
[0012]
Hydrolysis is performed by bringing a basic substance gas into contact with the metal salt supported on the carrier. As the basic substance, ammonia or lower alkyl represented by the general formula NR ₁ R ₂ R ₃ (wherein R ₁ , R ₂ and R ₃ each independently represents hydrogen or an alkyl group having 1 to 3 carbon atoms) Amines are used. When the basic substance is contacted at the lowest possible temperature, the hydroxide or oxide generated on the support tends to be finer and more dispersible. The reason for this is not clear, but it is considered that the mobility of the metal salt in the solid phase becomes higher as the temperature becomes higher.
[0013]
The basic substance is preferably diluted with an inert gas and gradually brought into contact. When the reaction proceeds rapidly, significant heat generation occurs, and the generated hydroxides and oxides tend not to be uniformly dispersed. For example, when ammonia is used as a basic substance, if it is not sufficiently diluted and brought into contact, intense heat generation may be observed even when contacting at room temperature or lower. Therefore, when ammonia is used, it is sufficiently diluted with an inert gas and contacted at 200 ° C. or lower, preferably 100 ° C. or lower. The usage-amount of a basic substance is 0.1-5 mol normally with respect to 1 mol of hydroxyl groups of the hydroxide produced | generated from the metal salt used as the object of hydrolysis.
[0014]
When a basic substance precursor is supported together with a metal salt, the basic substance precursor is thermally decomposed by heating without supplying the basic substance from the outside, and by the generated ammonia or other basic substance, A hydrolysis reaction can be performed. Of course, if desired, a basic substance may be used together from the outside. Thermal decomposition of the basic substance precursor generally occurs at a lower temperature, for example, 10 to 100 ° C. lower than when the basic substance is present alone. The reason for this is not clear, but it is presumed that hydroxides and oxides produced by the support and hydrolysis may act as a thermal decomposition catalyst. In any case, as described above, it is preferable that the hydrolysis reaction is performed at a low temperature. Therefore, it is advantageous for the present invention that the thermal decomposition reaction occurs at a low temperature. For example, when urea is used as the basic substance precursor, it may be heated to 90 to 200 ° C., preferably 90 to 150 ° C., and thermally decomposed.
[0015]
By the hydrolysis reaction, salts of basic substances such as ammonium salts such as ammonium nitrate, ammonium acetate and ammonium chloride and amine salts are formed on the carrier. These salts are converted from the following hydroxides to oxides. When it is fired, it disappears due to thermal decomposition or volatilization. However, if desired, these salts can be removed by washing with water prior to calcination. Since the metal hydroxide and oxide on the support are not changed even by such washing, the metal hydroxide and oxide generated during the hydrolysis reaction are separated from the support by the interaction with the support. It appears to be chemically bound. This is presumed to be the cause of the formation of extremely fine metal oxides.
[0016]
The metal hydroxide or metal oxide formed on the support by hydrolysis is usually subsequently calcined and converted into a metal oxide, and various catalytic reactions such as isomerization reaction, polymerization reaction, hydration as acid-base catalyst. Used for reaction, dehydration reaction, condensation reaction and the like. In particular, the supported catalyst in which the fine metal oxide obtained by the method of the present invention is highly dispersed on the support is particularly effective for the polymerization reaction of lower olefins and the ring-opening polymerization reaction of cyclic ethers. In addition, a metal-supported catalyst obtained by further reducing the metal oxide on the support, when used in a hydrogenation reaction, an oxidation reaction, an isomerization reaction, a disproportionation reaction, etc., compared to a catalyst by a conventional method, The activity per unit weight of the catalyst is remarkably high and the selectivity of the target product is also high. Thus, by the method of the present invention, the excellent performance of the supported catalyst obtained through the hydrolysis reaction in the solid phase state is that very fine particles highly dispersed are generated during the hydrolysis, and this is the metal oxide of the support. It is thought that it is due to combining with and complexing.
[0017]
【Example】
EXAMPLES The present invention will be described more specifically with reference to the following examples, but the present invention is not limited to these examples.
Example 1
Silica (product of Fuji Silysia Co., Ltd., Caractect Q-15, average pore size 150 mm, particle size 300 mesh or less) 5.0 g, zirconium oxynitrate dihydrate (ZrO (NO ₃ ) ₂ .2H ₂ O) It was added to 10 ml of an aqueous solution containing 17 g and 0.57 g of urea. Water was distilled off under reduced pressure at 60 ° C. to obtain an apparently dried solid. Under a stream of air, the solid was heated to 120 ° C. over 1 hour at a constant heating rate, and subsequently heated to 800 ° C. over 2 hours 30 minutes. The mixture was kept at 800 ° C. for 3 hours and then allowed to cool. The hydrolysis reaction is thought to have occurred around 95 ° C. When the average crystallite diameter of zirconium oxide (ZrO ₂ ) was measured by powder X-ray diffraction, it was 28 mm. It should be noted that as a silica, Carriert Q-30 (average pore diameter 300 mm, particle size 300 mesh or less) or Carriert Q-50 (average pore diameter 300 mm, particle size 300 mesh or less) is used instead of Carriert Q-15. The average crystallite diameter of zirconium oxide was 28 mm, although it was prepared in exactly the same manner except for the above.
[0018]
Comparative Example 1
In Example 1, zirconium oxide supported on silica was prepared in exactly the same manner as in Example 1 except that 10 ml of an aqueous solution containing only 1.17 g of zirconium oxynitrate was used. The average crystallite diameter of zirconium oxide obtained by powder X-ray diffraction was 200 mm.
[0019]
Example 2
In Example 1, zirconium oxide supported on silica was used in exactly the same manner as in Example 1 except that a spherical molded product (particle diameter 2 mmφ) of Carriert Q-15 was used instead of Carriert Q-15. Prepared. The average crystallite diameter of zirconium oxide obtained by powder X-ray diffraction was 28 mm.
[0020]
Example 3
Caractect Q-15 (5.0 g) was added to 10 ml of an aqueous solution containing 1.17 g of zirconium oxynitrate and dihydrate, and water was distilled off under reduced pressure at 60 ° C. The obtained solid in a dry state was filled into a quartz glass tube, and nitrogen at room temperature was passed through a 28% aqueous ammonia solution at a flow rate of 300 ml / min, and then supplied to the quartz glass tube. Immediate fever occurred. After 20 minutes, the temperature was raised to 800 ° C. over 2 hours and 30 minutes. The mixture was kept at 800 ° C. for 3 hours and then allowed to cool. When the average crystallite diameter of zirconium oxide was measured by powder X-ray diffraction, it was 28 mm. The obtained solid had a Zr / Si ratio (atomic ratio) of 1/19, which was the same as the Zr / Si ratio of the raw material used for the preparation.
[0021]
Example 4
In Example 3, nitrogen gas containing ammonia and water vapor was supplied to the quartz glass tube for 20 minutes, and then the solid was taken out from the quartz glass tube and washed with demineralized water. Next, the quartz glass tube was filled again, and the temperature was raised to 800 ° C. over 2 hours 30 minutes. The mixture was kept at 800 ° C. for 3 hours and then allowed to cool. When the average crystallite diameter of zirconium oxide was measured by powder X-ray diffraction, it was 28 mm. Further, the Zr / Si ratio (atomic ratio) of the obtained solid was 1/19. Therefore, it was confirmed that zirconium was fixed to silica as a carrier at the stage of treatment with nitrogen gas containing ammonia and water vapor.
[0022]
Example 5
Caractect Q-15 5.0 g was added to 35 ml of 40% aqueous methanol solution containing 1.17 g of zirconium nitrate dihydrate, 0.91 g of tetraethyl silicate and 1.14 g of urea, and water and methanol were added at 60 ° C. under reduced pressure. Distilled off. The resulting dried solid was heated to 120 ° C. over 1 hour under air flow, then heated to 800 ° C. over 2 hours and 30 minutes, held at 800 ° C. for 3 hours, and then allowed to cool. . The average crystallite diameter of zirconium oxide by a powder X-ray diffraction method was 28 mm.
[0023]
Example 6
Caractect Q-15 (5.0 g) was added to 10 ml of an aqueous solution in which 1.64 g of aluminum nitrate / 9-hydrate and 0.86 g of urea were dissolved. After distilling off water at 60 ° C. under reduced pressure, the obtained solid was heated to 120 ° C. over 1 hour under air flow, and then heated to 600 ° C. over 2 hours 30 minutes. The mixture was kept at 600 ° C. for 3 hours and then allowed to cool. When the crystallite diameter of alumina was measured by the powder X-ray diffraction method, it was below the detection limit.
[0024]
Comparative Example 2
39.5 g of tetraethyl silicate and 7.5 g of aluminum nitrate / 9-hydrate were dissolved in 600 ml of 70% ethanol water. 17% aqueous ammonia was added dropwise to this solution to cause hydrolysis. The formed precipitate was collected by filtration, washed with water, dried, and then calcined at 600 ° C. to prepare a silica-alumina composite oxide.
Tetrahydrofuran ring-opening polymerization A 100 ml flask was charged with 30 g of tetrahydrofuran, 1.53 g of acetic anhydride and 1.05 g of the oxide catalyst prepared in the above Examples and Comparative Examples, and reacted at 40 ° C. for 5 hours with stirring. After completion of the reaction, the catalyst was removed by filtration, and the reaction solution was analyzed by gas chromatography. The results are shown in Table 1.
[0025]
[Table 1]

Mw is the weight average molecular weight of the produced polymer,
Mn similarly represents a number average molecular weight.
[0026]
Partial hydrogenation of benzene 5 g of the zirconium oxide-supporting silica prepared in Example 2 was added to 100 ml of demineralized water. Next, ruthenium chloride and zinc nitrate were dissolved in this, stirred at 60 ° C., and then water was distilled off under reduced pressure at 60 ° C.
The obtained dry solid was filled in a Pyrex glass tube and reduced in a hydrogen stream at 200 ° C. for 2 hours to obtain a 0.5% Ru-0.5% Zn / ZrO ₂ —SiO ₂ catalyst.
[0027]
A 500 ml autoclave with a glass inner cylinder set was charged with 2.0 g of the catalyst obtained above, 7.2 g of zinc sulfate heptahydrate, 40 ml of benzene and 60 ml of demineralized water, temperature 150 ° C., hydrogen partial pressure 50 kg / cm. ^The reaction was performed at ² for 1 hour. After completion of the reaction, the mixture was cooled and the oil phase was collected and analyzed by gas chromatography. As a result, the benzene conversion was 62% and the cyclohexene selectivity was 78%.
In addition, except that the zirconium oxide-supported silica prepared in Comparative Example 1 was used, a reduction catalyst was prepared in the same manner as described above, and benzene was hydrogenated in the same manner as described above. The benzene conversion was 52% and the cyclohexene selectivity was 64%.

Claims (11)

After supporting a metal salt and / or metal alkoxide on a support and then bringing the metal salt and / or metal alkoxide into contact with a basic substance in a solid phase, the metal salt and / or metal alkoxide is converted into a corresponding metal. A method for supporting a metal hydroxide and / or an oxide on a support, which is converted to a hydroxide and / or an oxide. A method for supporting a metal oxide on a support, comprising supporting a metal salt and / or metal alkoxide on a support, bringing the basic substance into contact therewith in a solid phase and then heating to a high temperature. Carrying the metal salt and / or a metal alkoxide onto a carrier, a solution containing a metal salt and / or metal alkoxide is brought into contact with the carrier, then divided the liquid phase from the carrier, the metal salts and / or metal alkoxide 3. The supporting method according to claim 1, wherein the loading is carried out by bringing the material into a solid phase state . The basic substance is ammonia or amine represented by NR ₁ R ₂ R ₃ (R ₁ , R ₂ , R ₃ each independently represents hydrogen or an alkyl group having 1 to 3 carbon atoms). The supporting method according to any one of claims 1 to 3. A metal salt and / or a metal alkoxide and a basic substance precursor that generates a basic substance by thermal decomposition are supported on a carrier, and then the metal salt and A method for supporting a metal hydroxide and / or oxide on a support, wherein the metal alkoxide is converted into a corresponding metal hydroxide and / or oxide. After a metal salt and / or metal alkoxide and a basic substance precursor that generates a basic substance by pyrolysis are supported on a support, the precursor is thermally decomposed by heating in a solid phase, and then further heated to a higher temperature. A method for supporting a metal oxide on a support, which is characterized by heating the substrate. Carrying the metal salt and / or metal alkoxide and basic material precursor onto the support is a solution containing these into contact with the carrier, then divided the liquid phase from the carrier, the metal salts and / or metal alkoxide 7. The supporting method according to claim 5, wherein the supporting method is carried out by bringing the material into a solid phase state .   The basic substance precursor is selected from urea, alkyl-substituted urea, thiourea, alkyl-substituted thiourea, and an organic compound having both a carboxyl group and an amino group. The loading method according to claim 1.   9. The supporting method according to claim 1, wherein the carrier is a metal oxide. 9. The support according to claim 1, wherein the support is at least one metal oxide selected from Group II of the Periodic Table, Group III, Group IV, Group V and Group VIA containing rare earths. The supporting method described in 1. The metal salt or metal alkoxide is a metal salt or alkoxide selected from Group II, Group III, Group IV, Group V, Group VIA, Group VIA and Group VIII of the periodic table. The supporting method according to claim 1.