JPH02290258A - Manufacture of porous high dispersing metal catalyst using multi-component metal oxide as carrier - Google Patents

Abstract

PURPOSE:To manufacture a porous high dispersing metal catalyst of high performance by mixing an oxygen contained organic metal compound and easily reducing metal salt in the liquid of a polar compound having multidentate or crosslinking coordination power and then gelatinizing and heat treating said gel at low temperature. CONSTITUTION:Alcoxide such as gel aluminum and titanium, an oxygen contained organic metal compound such as a diketone compound and easily reducing metal salt such as copper, silver, iron or the like are mixed in polar compound contained solution having multidentate or crosslinking coordination power such as bivalent alcohol or amino at 10-200 deg.C. Then, the hydrolysis is carried out for the same and the whole of sol is gelatinized from uniform sol. Then, said gel is heat treated in reduced atmosphere after low temperature drying at 30-200 deg.C, to scatter a polar compound and reduce the reducing metal salt into metal. Thus, a metal catalyst highly dispersed in a multi-component non-crystalline metal oxide is manufactured, which forms the catalyst of high performance.

Description

Detailed Description of the Invention The present invention provides a homogeneous solution by mixing an oxygen-containing organometallic compound and an easily reducible metal salt serving as a catalytic metal species in a solution containing a polar compound having polydentate or bridging coordination ability. The composite metal oxide carrier is then subjected to a gelation process in which the entire sol is gelled from a uniform sol by hydrolysis, and a process of drying the gel at a low temperature and then heat treating it in a reducing atmosphere. The present invention relates to a method for producing a porous highly dispersed metal catalyst.

Non-quality composite metal oxides have many uses, including commonly used glass, catalysts, adsorbents, sensor optical semiconductors, and magnetic materials. If points are excluded, the synthesis methods can be summarized into the following two methods. In other words, there are methods in which metal oxides or metal hydroxides are precipitated by adding acid or alkali to an aqueous solution of inorganic metal salts, and methods in which metal alkoxides are dissolved in ethanol, propanol, etc. and water is added to the solution for hydrolysis. This is a method for obtaining metal oxides or gold hydroxides.

The former method is easy, but it has the disadvantage that it is difficult to eliminate impurities contained in the raw materials, and the salts used to generate the precipitation are easily incorporated as impurities. There is also a drawback that homogeneity is not necessarily maintained during the growth of the precipitate because it is often produced with extremely minute precipitates F;9 as nuclei. On the other hand, in the latter method, the metal alkoxide is distilled or processed into ff! It is relatively easy to eliminate impurities because U-east can be used, but maintaining homogeneity is not necessarily easy, as in the former case. This is because during hydrolysis, gelation does not proceed smoothly depending on the conditions, and a precipitate often precipitates as in the former case.

In particular, in mixed systems of different metals, the susceptibility to hydrolysis differs depending on the metal type, so precipitation is likely to occur and uniform gelation is difficult, making it difficult to obtain sufficiently homogeneous gel for high-performance materials such as catalysts. be.

When using composite metal oxides as catalysts, adsorbents, sensors, etc., the surface area and pores of the composite metal oxide are always important considerations. Methods for controlling the surface area and pore structure include adding polyethylene glycol, polyvinyl alcohol, polyacrylamide, and cellulose ether to the gel immediately after hydrolysis or drying, washing the gel with monohydric alcohol, acid treatment, and hydrothermal treatment. There are various methods, such as oxidation and sintering, and each has its own characteristics and advantages, but it is limited to special materials such as alumina, and it is difficult to control over a wide range using each individual method alone. In addition, these treatments may introduce impurities or change the properties of the metal oxide. Other controlled porosity methods include methods for producing porous glass. With this method, the pore size can be changed from a few pores to several thousand pores by heat treatment and acid treatment, but at present it is possible to change the pore size from a few pores to several thousand pores. The scope of application is extremely narrow, as it is limited to the production of a few composite metal oxides including cerium dioxide and cerium dioxide.

Methods of preparing catalysts using metal alkoxides are also known, including Ru-SiO, Rh-Sin2, Ni-Si
Various catalysts such as n2 have been announced. however,
These metal supported catalysts are almost limited to Si island supported catalysts.
A titania-supported catalyst [Catalyst Vol. 24, p. 58 (1982)] has also been announced, but perhaps because only ethylene glycol is used in the preparation of the catalyst, no high-performance catalyst has been obtained except for the SjO■-supported catalyst. do not have. This is because alkoxides of titanium and aluminum form insoluble precipitates with ethylene glycol, and it is natural that such a combination cannot produce the desired uniform porous oxide.

The present inventors kept this point in mind and conducted various studies to produce a metal catalyst using a homogeneous and non-quality composite metal compound with a controlled surface and pores as a carrier. The present invention was achieved by discovering a method for producing a highly dispersed metal catalyst using a composite oxide as a carrier by conveniently using bulky diols.

The present invention combines two or more oxygen-containing organometallic compounds and an easily reducible metal salt serving as a catalytic metal species at a temperature of 10°C to 200°C with one type of polar compound having polydentate or crosslinking coordination ability, or at least 2MI. Mix in a solution containing to make a homogeneous solution,
A porous structure using a composite hydronide as a carrier, which is characterized in that the homogeneous sol is then subjected to a gelling step in which the entire sol is gelled by hydrolysis, and the gel is dried at low temperature and then heat treated in a reducing atmosphere. The present invention provides a method for producing a highly dispersed metal catalyst.

In the present invention, the first step to prepare a homogeneous composite metal oxide is to prepare a homogeneous solution. ．．
It is important to keep in mind that a number of oxygen-containing organometallic compounds, easily reducible metal salts, and polar compounds having polydentate or bridging coordination ability form a homogeneous solution without forming precipitates. For this purpose, the combination of the oxygen-containing organometallic compound and the polar compound having polydentate or bridging coordination ability, and the mixing temperature are often important issues. For example, oxygen-containing organometallic compounds such as aluminum, titanium, and zirconium, especially alkoxides, form insoluble precipitates with ethylene glycol and propanediol. It is necessary to select oxygen-containing compounds with a high degree of branching (dihydric alcohols, keto alcohols, carboxylic acids),
The effects of these additions are surprising. On the other hand, oxygen-containing organometallic compounds of silicon and boron, especially their alkoxides, do not have this problem, and almost all dihydric alcohols, amino alcohols, keto alcohols, ketocarboxylic acids, oxycarboxylic acids, dicarboxylic acids, etc. Because it can be used. When preparing a complex oxide mainly composed of Sin2, an inexpensive solvent mainly composed of ethylene glycol may be used, and a small amount of amino alcohol or keto alcohol may be added to maintain the uniformity of the prepared solution.

If the mixing temperature is too high, an abnormal reaction may occur between the polar compound and the oxygen-containing organometallic compound, resulting in the formation of an insoluble precipitate, so it is necessary to avoid excessive heating.
The heating temperature is 10 to 200°C, preferably 20 to 8°C.
0℃ is good. High mixing temperatures often etherify hydroxyl groups and esterify carboxyl groups. In such a case, the polydentate and crosslinking coordination abilities of the polar compound are significantly reduced, and therefore, in order to prevent such etherification and esterification, the mixing temperature is preferably 20 to 80°C.

Next, the amount of polar compounds to be used is an important issue in order to compensate for the decrease in polar compounds due to unavoidable etherification and esterification, and to ensure smooth solization and gelation. The amount of the polar compound with polydentate or cross-coordination ability is important for the pore and surface design of the final composite metal oxide, but if it is too small, gelation will not proceed smoothly and hydration will be difficult. Decomposition often results in precipitation or takes too long. On the other hand, if too much is used, gelation will not be uniform and the gel will float in the solution, and also in this case gelation will take too long. Therefore, the amount of the compound having cross-linking coordination ability should be 0.01 to 15 in molar ratio to the amount of the oxygen-containing organometallic compound used, preferably 0.1. 5 is appropriate.

Another important issue in gelling is the amount of water used. If the amount of water added is too small, it will take several days or more for gelation, and if it is too much, uniform gelation will be difficult. Therefore, the amount of water used during hydrolysis is from 0.5 to 20 molar ratio to the oxygen-containing organometallic compound.
, preferably 1 or 610.

The oxygen-containing organometallic compounds used in the present invention are sometimes difficult to hydrolyze depending on the metal intercalant and the ligand. In such a case, if a hydrolysis accelerator such as an acid or an alkali is used, hydrolysis can proceed quickly and gelation can be smoothly performed. The hydrolysis accelerator can be any ordinary inorganic acid, organic acid, inorganic alkali, or organic alkali, as long as it is soluble, but it is preferable that the hydrolysis accelerator remains in the final metal oxide. If so, organic acids (carboxylic acids, ketocarboxylic acids,
Oxycarboxylic acids, etc.) or organic alkalis (amines, amino alcohols, etc.) such as formic acid, oxalic acid, tartaric acid, malonic acid, succinic acid, ethanolamine, propanolamine, etc. are preferably used.

Metal oxides are mixed with various additives. What is done is to change its properties. For example, boria, silica,
Alumina, titania, and zirconia are often mixed with each other, and alkali metal or alkaline earth metal oxides or transition gold gX@ oxides are mixed therein. This is also possible in the present invention, and includes alkali metal elements, zinc group elements, first transition series elements, second transition series elements, third transition series elements, lanthanide elements,
Actinide elements, scandium, yttrium, gallium, indium, thallium, germanium, tin, lead, phosphorus, arsenic, antimony, bismuth, sulfur, selenium,
A compound selected from tellurium, boronium, and astatine can be incorporated as a soluble compound during chemical mixing.

By the methods and operations described above, a homogeneous gel can generally be smoothly produced within several hours. Next, the jelly-like or agar-like gel is ground to an appropriate size and dried at a temperature of 30°C to 200°C, preferably 80°C to 110°C, under reduced pressure for several hours to 30 hours. After drying, heat treatment is performed in a reducing atmosphere to scatter the remaining polar compounds with polydentate or bridging coordination ability, and to reduce the reducing metal salts to metals, resulting in highly dispersed compounds in the composite non-quality metal oxide. A metal catalyst is obtained.

The composite metal oxide formed by the method described above has been confirmed to be non-quality and homogeneous by powder X-ray diffraction and electron microscopy, and it has been confirmed by surface area measurement by the 1'3ET method and by measurements of methylbentane, n- The surface area and pore distribution were determined by measuring the pores using a pulse adsorption method using adsorption such as hexane, and it was confirmed that the surface area and pores were controlled by the formulation method during manufacturing. That is, in Silica Al + (11111 Notena, the surface area is 50
-1000 mr/g, the pore diameter is distributed in 50 mr/g or less, and it is extremely difficult to control the pore volume and pores over a wide range, especially in complex metal oxides containing silica alumina, using general manufacturing methods. This was made possible for the first time by the present invention.

The catalyst of the present invention obtained in this way has high homogeneity,
It can be effectively used for oxidation, isomerization, cracking, hydration, and hydrogenation. The ratio of the easily reducible metal salt used as the catalytic metal species is 0.01 to 1% of the oxygen-containing organometallic compound.
It is 0 mol%, preferably 0.1 to 5 mol%. The heat treatment in a reducing atmosphere can be performed by firing at a temperature of 200 to 1000°C, thereby obtaining a porous highly decomposed metal catalyst using a composite oxide as a carrier. Since this catalyst is a multifunctional catalyst with regular pores, it is particularly effective as a catalyst for petroleum refining such as isomerization, hydrogenation, and cyclization.

In this case, the easily reducible metal salts include copper, silver, gold, iron, cobalt, nickel, rhodium, palladium, ruthenium, platinum, iridium, osmium (I+), chromium, tungsten, molybdenum, manganese, rhenium. Salts of metals selected from zinc and zinc are used, and these salts may be added in the form of alkoxides or acetylacetonates, but they may also be added in the form of chlorides or other forms that convert into alkoxides within the system. The firing atmosphere may be determined as appropriate depending on the type of salt. Hydrogen is preferable as the firing atmosphere, and hydrogen or a hydrogen-containing gas is generally used.

Next, the present invention will be explained in more detail with reference to Examples and Reference Examples.

Reference example 1 300-40. 1 g of hexylene glycol was added, and 23.7 g of aluminum see-butoxide and 50.50 g of tetraethoxysilane were dissolved therein. After heating at 85°C with stirring for 1 hour,
Cool to ℃. A solution consisting of 20 g of ethylene glycol and 20 g of hexylene glycol containing 0.2 g of α-hydroxyisobutyric acid was added to this solution, and
Warm up time. Next, add 50 parts of ethanol to this solution and stir it at the same temperature to form an agar-like gel.After standing overnight at 25°C, cut the gel into an appropriate size. It was crushed into pieces, placed in a 300 mQ eggplant-shaped flask, and dried under reduced pressure at 100°C using a rotary evaporator for 24 hours. Yield: 59.8 g.

The dried gel was pulverized, spread in a quartz tube, and incubated in air for 500 min.
Heat treatment was performed at ℃ for 6 hours. Surface area 567rrr/g.
More than 35 pulse adsorptions of n-hexane.

Reference Example 2 Put 50ml2 of tart-butanol in a 300+nl2 beaker, add 50g of 1,2-cyclohexanediol, 48.54g of tetraethoxysilane and 10ml of tart-butanol.
Dissolve 4.2 g of methanol containing % hydrogen chloride and warm at 80°C for 2 hours with stirring. Next 35.6g
After adding ethylaluminum dibutoxyacetoacetate and heating at the same temperature for 1 hour, 12 g of water was added and the mixture solidified into agar-like form while stirring. All subsequent operations were performed in the same manner as in Reference Example 1. 13 pulse adsorptions of 3-methylpentane with a surface area of 500 m/g.

Reference Example 3 Put 10.0g of ethanol in a 200-beaker, dissolve 10g of cerium ammonium nitrate therein, add 50g of hexylene glycol and 19.6g of tetraethoxysilane, and heat at 75°C for 4 hours. Stir. Next, 30ml of ethanol solution containing 3.7g of water
After adding Q and stirring while heating at the same temperature for 1 hour, 7.4 g of water was further added and the mixture solidified into a jelly while stirring at the same temperature. All subsequent operations were performed in the same manner as in Reference Example 1. Surface area 430rrr/g.

Seven pulse adsorptions of n-hexane.

Reference example 4 Put 50g of ethanol in a 300+nl2 beaker,
25.2 g of triethyl borate, 48.6 g of tetraethoxysilane and 50.1 g of 1,2-cyclohexanediol were dissolved in this, 10 ml of methanol containing 2 g of tartaric acid was added to this solution, and 3. Warm with stirring for 5 hours. Next, 13.5 g of water was added and the mixture gelled while stirring at the same temperature. All subsequent operations were performed in the same manner as in Reference Example 1. Surface area 673nl'/g.
2. Pulse adsorption of 2-dimethylbutane 3 times and 3-methylpentachloride 8 times.

Reference Example 5 Put 50% of ethanol in a 200% beaker, dissolve 0.6g of titanium ethoxide in it, and add 50g of 2,3-butanediol, 69.0g of tetraethoxysilane and 10% of ethanol to this solution. Methanol containing hydrogen chloride 5
Add 0- and stir while warming at 80°C for 3 hours.

Next, 30 g of ethanol containing 12 g of water was added, and after stirring at the same temperature for 2.5 hours, 6 g of water was further added and solidified into agar while stirring. All subsequent operations were performed in the same manner as in Reference Example 1. Surface area 534rrf/g. 3
- Seven pulse adsorptions of methylpentane.

Reference Example 6 50 d of tert-butanol is placed in a 300 mQ beaker, and 21.4 g of titanium iso-propoxide is dissolved therein. 50 g of hexylene glycol and 67.8 g of aluminum sec-butoxide are added to this solution, and the mixture is heated at 65° C. for 2 hours with stirring. Next, tert-butanol containing 12 g of water is added to this solution, and the mixture turns into a gel while stirring at the same temperature. All subsequent operations were performed in the same manner as in Reference Example 1. Surface area 230 i/
g. Pulse adsorption of n-hexane 13 times.

Reference Example 7 A 300-liter beaker was charged with 50-liter ethanol, and 16.0 g of zirconium n-proboxoxide and 50 g of 1,2-cyclohexanediol were dissolved therein. Next, 48.7 g of tetraethoxysilane and 5 mil of methanol containing 10% hydrogen chloride were added to this solution, and
After warming with stirring for an hour, lo. 5 g of water was added dropwise and the mixture solidified while stirring at the same temperature. All subsequent operations were performed in the same manner as in Reference Example 1. Surface area 308r
r? /g. 9 pulse adsorptions of n-hexane.

Reference Example 8 50+m2 of tert-butanol is placed in a 300-m beaker, and 8.4 g of triethyl borate is dissolved in this solution. 73.5 g of 2,3-butanediol and 53.7 g of titanium ethoxide were added to this solution, and the mixture was heated at 75°C.
After heating with stirring for 3 hours, tert-butanol 60 g containing 10 g of water was added, and as the mixture was continued to stir at the same temperature, it solidified. Are all subsequent operations for reference? I did the same thing as Ding. Surface area 45m/g.

Example 1 80 g of ethylene glycol is placed in a 300 ml beaker, and 3 g of ruthenium trichloride is dissolved therein. To this i6M, add 910g of tetraethoxysilane and 23.6
g of triethyl borate was added, and the mixture was heated at 70°C for 3 hours with stirring. Next, 12 g of water was added, and after stirring at the same temperature for 1 hour, another 12 g of water was added, and while stirring at the same temperature, the mixture solidified into agar-like form. After standing at 25°C overnight, crush it into pieces of appropriate size, put it in a 300-inch eggplant-shaped flask, and use a rotary evaporator under reduced pressure.
Dry at 100°C for 24 hours.

The dried gel was pulverized, spread in a quartz tube, and incubated in a hydrogen stream for 4 hours.
Heat treatment was performed at 00°C for 8 hours, and 3.5wt%Ru-B2
0,-SiO2 is obtained. This substance did not show any diffraction lines in powder X-ray diffraction, and no metal particles were observed in electron microscopy, but elemental analysis confirmed ruthenium. It was confirmed that it was highly dispersed, homogeneous, and of poor quality.

Example 1 Example 2 59.5 g of tetraethoxysilane and 10.3 g of aluminum see-butoxide are placed in a 300° beaker and heated at 75° C. for 1 hour. Add 50g of hexylene glycol to this solution. Add 25 ml of ethanol in which 1.5 g of nickel chloride was dissolved. Heat at 70℃ for 3 hours. Next, ethanol containing 8 g of water is added and the mixture is stirred at the same temperature to form an agar-like gel. The subsequent operations were the same as in Example 1 except that the heat treatment was performed at 500°C. In this case as well, the results of X-ray diffraction and electron microscopy were the same as in Example 1, so it was confirmed that the material was homogeneous and of poor quality, and that nickel was highly dispersed in less than 20 particles.

Claims (11)

[Claims] (1) At a temperature of 10°C to 200°C, two or more oxygen-containing organometallic compounds and an easily reducible metal salt serving as a catalytic metal species are combined with one or two polar compounds having polydentate or bridging coordination ability. mixing in a solution containing at least one species to form a homogeneous solution, and then passing through a gelation step in which the entire sol is gelled from a homogeneous sol by hydrolysis in the above temperature range;
A method for producing a porous highly dispersed metal catalyst using a composite metal oxide as a carrier, which comprises drying the gel at a low temperature of 30°C to 200°C and then heat-treating it in a reducing atmosphere. (2) The oxygen-containing organometallic compound is one or a mixture of two or more selected from alkoxides, ketoalcohol compounds, diketone compounds, ketocarboxylic acid compounds, and oxycarboxylic acid compounds, or in the mixed solution of item 1. 2. The method of claim 1, wherein the metal salts forming these oxygen-containing organometallic compounds. (3) The metal species of one of the oxygen-containing organometallic compounds used is boron, aluminum, silicon, titanium, or zirconium, and in the final metal oxide, boria, alumina, silica, titania, etc. , the weight content of one type of zirconia or the total weight content of two or more types is 25% or more, and furthermore, the total amount of the oxygen-containing organometallic compound in the solution is 10% to 90% of the total solution
The method of claim 1 or 2 within the scope of. (4) A polar compound having polydentate or crosslinking coordination ability is
dihydric alcohol, amino alcohol, keto alcohol,
The method according to any one of claims 1 to 3, wherein the method is one or a mixture of two or more selected from diketones, ketocarboxylic acids, oxycarboxylic acids, and dicarboxylic acids. (5) Diol whose dihydric alcohol has 14 or less carbon atoms
5. The method of claim 4, which is a species or a mixture of two or more species. (6) The mixing ratio of the polar compound having polydentate or crosslinking coordination ability and the oxygen-containing organometallic compound is from 0.01 to 15 in molar ratio (polar compound/organometallic compound) Any method in Section 5. (7) Chemical mixing and hydrolysis temperature from 20℃ to 150℃
7. The method according to any one of claims 1 to 6, wherein the temperature is .degree. (8) The amount of water used during hydrolysis is 0 in molar ratio (water/oxygen-containing organometallic compound) to the oxygen-containing organometallic compound.
．． 5 to 20. The method according to any one of claims 1 to 7. (9) Easily reducible metal salts serving as catalytic metal species are contained in copper, silver, iron, cobalt, nickel, rhodium, palladium, ruthenium, platinum, iridium, osmium, chromium, tungsten, molybdenum, manganese, rhenium, and zinc. The method according to any one of claims 1 to 8, which is at least one selected from. (10) The method according to any one of claims 1 to 9, wherein the amount of the easily reducible metal salt added is 0.01 to 10 mol% of the total amount of oxygen-containing organometallic compound serving as a carrier. (11) Heat treatment temperature under reducing atmosphere ranges from 200℃ to 10℃
11. The method according to any one of claims 1 to 10, wherein the temperature is 00°C.