JPH067921B2 - Method for producing supported catalyst - Google Patents

Description

The present invention relates to a method for supporting a white metal element on a porous carrier (hereinafter referred to as "carrier"). For more details,
The present invention relates to a method for producing a supported catalyst in which all or most of the white metal element is supported on the surface layer of a carrier.

(Prior Art) A supported catalyst in which a white metal element is supported on a carrier is widely used for hydrogenation reaction of various organic compounds, hydrocracking reaction, catalytic conversion reaction of automobile exhaust gas, etc. Because of its high speed, it advances on the outer surface of the catalyst particles and the metal inside the catalyst particles is not effectively used. Therefore, when an expensive white metal element is used as a catalyst substance, it is necessary to support the white metal element at a high density on the surface layer of the carrier for effective use.

Conventionally, as a method of supporting a white metal element on the surface layer of a carrier, a basic solid oxide carrier or a pretreated basic carrier is added with an aqueous solution of a white metal element compound and hydrolyzed by a base on the carrier surface. There is known a method of causing the white metal element to deposit on the surface layer portion. However, according to this method, the carrier is limited, and depending on the type of the carrier, the white metal element may permeate into the inside of the carrier and the purpose may not be achieved.

For that purpose, a method of adjusting the pH of an aqueous solution of a white metal element compound (Japanese Patent Publication No. 47-35670), a method of using an acetone solution of a white metal element compound as an impregnating liquid (Japanese Patent Publication No. 48-53980), polyethylene glycol Alternatively, a method of adding a nonionic surfactant to the impregnating solution (JP-A-49-111886 and JP-A-49-114588), and a method of pre-impregnating a catalyst carrier with a citric acid solution (JP-A-54) -149391 gazette) etc. are proposed. However, in any of the methods, the white metal element may penetrate not only into the surface layer portion of the carrier but also into the inside thereof, and the purpose cannot always be achieved. In addition, the catalytic activity may decrease depending on the method.

(Problems to be Solved by the Invention) A problem to be solved by the present invention, that is, an object of the present invention is to eliminate the drawbacks of the conventional methods as described above, and to make the surface layer of the carrier white in a very simple and inexpensive manner. It is intended to provide a method for supporting a metal element. That is, by immersing the carrier in advance in a hydrocarbon compound having 5 to 12 carbon atoms and then impregnating the carrier with an aqueous solution of a white metal element, all or most of the white metal element is supported on the surface layer portion of the carrier. It has been found.

(Means for Solving Problems) Examples of the hydrocarbon compound having 5 to 12 carbon atoms used in the present invention include aliphatic hydrocarbons such as pentane, hexane, octane, pentene and hexene, cyclopentane,
There are alicyclic hydrocarbons such as cyclohexane and methylcyclopentane, and aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene, preferably having 6 carbon atoms.
To 10 hydrocarbon compounds are used. These hydrocarbon compounds may be used alone or in combination of two or more.

The conditions for immersing the carrier in the hydrocarbon compound are not particularly limited, but usually the carrier is immersed in the hydrocarbon compound for 10 minutes to 10 hours at room temperature.

The carrier used in the method of the present invention has a surface area of 1 to 1000 m ^2.
/ g of porous carrier. Specifically, alumina, silica,
Silica-alumina, magnesia, titania, zirconia,
There are niobium oxide and the like. The method of the present invention is not particularly limited as long as it is a porous carrier, but the effect is remarkably exhibited in an acidic carrier as compared with the conventional method.

The white metal elements used in the method of the present invention include palladium, ruthenium, rhodium, platinum, osmium, and iridium, and as the platinum group element compounds, chlorides, nitrates, and metal salts of these white metal elements are usually used. To be Specifically, palladium chloride, palladium nitrate, ruthenium chloride, chloroplatinic acid, etc. are used.

As a method for supporting the white metal element on the carrier, the carrier may be immersed in an aqueous solution of the white metal element compound, but a method of spraying the aqueous solution of the white metal element compound onto the carrier by a spray or the like is preferably used.

The amount of the white metal element carried is usually 0.01 to 10 g, preferably 0.1 to 5 g per liter of the carrier.

(Example) Example 1. Silica-alumina pellets (N-631HN manufactured by JGC Chemical Co., Ltd.) were used as the porous carrier.

Take 100 ml of silica-alumina pellets and add 500
Immersion in ml of benzene at room temperature for 1 hour. After 1 hour, the silica-alumina pellets were taken out, and a liquid prepared by diluting 2.7 ml of an aqueous palladium chloride solution (palladium concentration: 37 g / 1) with 11 ml of pure water was spray-impregnated into this carrier. After that, palladium was reduced with hydrazine and dried at 150 ° C. for 10 hours to obtain a supported catalyst.

The palladium-supported state of the catalyst thus obtained was determined as X.
When measured by a line microanalyzer, 97% or more of palladium was supported within 0.2 mm of the surface layer of the carrier. Examples 2 to 6 and Comparative Examples 1 to 4 After immersing in the compounds shown in Table 1 for 1 hour instead of benzene used in Example 1, palladium loading operation was carried out to obtain palladium as a supported catalyst. The supported state was measured with an X-ray microanalyzer to obtain the results shown in Table 1. The same procedure as in Example 1 was carried out except that another compound was used as the immersion liquid instead of benzene.

Examples 7 to 10 Instead of the silica-alumina used in Example 1, 100 ml of the carrier described in Table 2 was used to carry out the palladium loading operation. The palladium-supported state of the resulting supported catalyst was measured by an X-ray microanalyzer, and the results shown in Table 2 were obtained. The procedure was the same as that described in Example 1 except that the carrier was different.

Examples 11 to 14 Third Example Instead of Palladium Chloride Aqueous Solution Used in Example 1
A white metal element was loaded using the solutions listed in the table. The supported state of the white metal element of the obtained supported catalyst was measured by an X-ray microanalyzer, and the results shown in Table 3 were obtained. As the impregnating solution, 14 ml of a solution prepared so that the amount of supported metal was 0.1 g / 1 was used. Further, the same method as described in Example 1 was used except that the impregnating liquid was different.

Example 15 Gamma Alumina Pellets 1 Same as Used in Example 7
00 ml was immersed in 500 ml of benzene at room temperature for 1 hour. Take out the gamma-alumina pellet after 1 hour,
Next, aqueous palladium chloride solution (palladium concentration 37g / 1)
This carrier was immersed in a solution diluted with 2.7 ml of pure water for 30 minutes. Then, reduce the palladium with hydrazine,
Drying was carried out at 0 ° C. for 10 hours to obtain a supported catalyst. When the palladium-supported state of the resulting supported catalyst was measured by an X-ray microanalyzer, it was confirmed that 96% or more of the palladium was supported within 0.2 mm of the surface layer of the carrier. (Effects of the Invention) As described above, according to the present invention, the white metal element can be easily supported on the surface layer of the carrier in a high ratio, and the catalyst supporting the white metal element is a reducing liquid such as hydrazine or formalin or hydrogen. After reduction with gas and washing with water and drying, the catalyst can exhibit good performance as a hydrogenation catalyst.

Claims (1)

[Claims] 1. A method of supporting a white metal element on a porous carrier, wherein the porous carrier is preliminarily prepared with a carbon number of 5 to 12.
The method for producing a supported catalyst, which comprises immersing in an aqueous solution of a white metal element compound after being dipped in the hydrocarbon compound of.