JPS6214943A - Preparation of supported catalyst - Google Patents

Abstract

PURPOSE:To enhance catalytic activity by supporting a platinum group element at a high ratio, by immersing a porous carrier in a 5-12C hydrocarbon compound and subsequently impregnating the same with an aqueous solution of a platinum group compound to form a supported catalyst. CONSTITUTION:A porous carrier with surface area of 1-1,000m<2>/g formed of alumina, silica, silica-alumina, magnesia or titania is immersed in a 5-12C hydrocarbon compound and subsequently impregnated with an aqueous solution of a platinum group compound to prepare a supported catalyst. As the aforementioned 5-12C hydrocarbon compound, aliphatic hydrocarbon such as pentane, hexane or octane and alicyclic hydrocarbon such as cyclopentane are used. As the platinum group compound, there are palladium chloride, palladium nitrate, ruthenium chloride and platinic chloride, etc.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for supporting a platinum metal element on a porous carrier (hereinafter referred to as "carrier").
This relates to a method for manufacturing a supported catalyst in which all or most of a platinum metal element is supported on the surface layer of a support. (Prior art) A supported catalyst in which a platinum metal element is supported on a support is used for hydrogenation reactions of various organic compounds. It is widely used in catalytic conversion reactions, hydrocracking reactions, and catalytic conversion reactions of automobile exhaust gas, but these reactions are generally very fast and proceed on the outer surface of the catalyst, so that the metal inside the catalyst particles is not used effectively. Therefore, when using an expensive platinum metal element as a catalytic material, it is necessary to support the white metal element in a high density on the surface layer of the support for effective use. The method for supporting the metal element is to add an aqueous solution of the platinum element compound to a basic solid oxide carrier or a carrier that has been pretreated to make it basic, and cause hydrolysis by the base on the surface of the carrier to cause the platinum element to be deposited on the surface layer. However, this method has limitations on the carrier, and depending on the type of carrier, the platinum metal base may penetrate into the interior of the carrier, making it impossible to achieve the purpose. A method for adjusting the pH of an aqueous solution of a platinum metal element compound (Japanese Patent Publication No. 47-85670), a method using an acetone solution of a platinum metal element compound as an impregnating liquid (Japanese Patent Application Laid-open No. 48-58980), polyethylene glycol/ L
/l or a method of adding a nonionic surfactant to the impregnating liquid (JP-A-49-111886, JP-A-49-11)
4588) and a method of pre-impregnating a catalyst carrier with a citric acid solution (Japanese Unexamined Patent Publication No. 149891/1989). However, in any of these methods, the platinum metal element may penetrate not only into the surface layer of the carrier but also into the interior thereof, so that the purpose cannot necessarily be achieved. In addition, depending on the method, the catalyst activity may be reduced. The present invention provides a method for supporting a platinum metal element on the surface layer of a carrier very simply and at low cost. That is, all or most of the platinum metal element is supported on the surface layer of the support by first immersing the support in a hydrocarbon compound having 5 to 12 carbon atoms and then impregnating the support with an aqueous solution of the platinum metal element compound Q. (Means for solving the problem) Hydrocarbon compounds having 5 to 12 carbon atoms used in the present invention include aliphatic hydrocarbons such as pentane, hexane, octane, pentene, and hexene. , cyclopentane,
Alicyclic hydrocarbons such as cyclohexane and methylcyclopentane, and aromatic hydrocarbons such as benzene, toluene, xylene and ethylbenzene, preferably 6 carbon atoms.
From 1 to 10 hydrocarbon compounds are used.

These hydrocarbon compounds may be used alone or in combination of two or more.

Although the conditions for immersing the carrier in the hydrocarbon compound are not particularly limited, the carrier is usually 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 100.
It is a porous carrier of 0 m'/f. Specifically, there are alumina, silica, silica alumina, magnesia, titania, zirconia, 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 more pronounced when using an acidic carrier than in the conventional method.

The platinum metal elements used in the method of the present invention include palladium, ruthenium, rhodium, platinum, onumium, and iridium, and the compounds of these platinum group elements usually include chlorides, nitrates, metal salts, etc. of these platinum metal elements. Specifically, palladium chloride, palladium nitrate, ruthenium chloride, chloroplatinic acid, etc. are used.As a method for supporting a platinum metal element on a carrier, the carrier may be immersed in an aqueous solution of a platinum element compound. , a method of spraying an aqueous solution of a platinum metal element compound onto the carrier using a spray or the like is preferably used.

The amount of platinum metal element supported is usually 0.01 to 10 f per 1 liter of carrier, preferably a silica alumina pellet (N-681HN manufactured by 8 Kiku Kagaku Co., Ltd.) as a porous carrier.
Take 100 mj of 0 silica alumina beret using
This was immersed in 500 mj of benzene at room temperature for 1 hour. After 1 hour, take out the silica alumina pellet and add palladium chloride aqueous solution (palladium concentration 87 f/1) 2.
This carrier was impregnated by spraying with a solution obtained by diluting 7 mJ with 11 mJ of pure water. Thereafter, palladium was reduced with hydrazino and dried at 150° C. for 10 hours to obtain a supported catalyst.

The palladium supported state of the catalyst obtained in this way is
When measured using a wire microanalyzer, more than 97% of the palladium was supported within 0.2 cm of the surface layer of the carrier.

Examples 2 to 6 and Comparative Examples 1 to 8 The benzene wash used in Example 1 was immersed in the compounds listed in Table 1 for 1 hour, and palladium was then supported. The supported state of palladium was measured using an X-ray microanalyzer and the results listed in Table 1 were obtained. 1
Table A: Ratio of palladium supported within 0.2cm of the surface layer Examples 7 to 10 Palladium was supported on the silica alumina glue used in Example 1 using carrier 1001117 listed in Table 2. The state of palladium supported on the obtained supported catalyst was measured using an X-ray microanalyzer, and the results shown in Table 2 were obtained. Table 2 Table A: Table #0 was carried out in the same manner as described in Example 1 except that the carrier was different. Ratio of palladium supported within gfi Examples 11-14 5j! The platinum metal element was supported using the solution listed in Table 8 instead of the palladium chloride aqueous solution used in Example 1. The supported state of the platinum metal element on the obtained supported catalyst was
It was measured with a line microanalyzer and the results listed in the table were obtained. All were performed in the same manner as described in Example 1. Example 15 The same gamma-alumina pellet i used in Example 7.
o OmJ was immersed in 50 OmJ of benzene for 1 hour at room temperature.
F/1) The carrier was immersed in a solution diluted with 2.7 mj of pure water for 80 minutes, and then the palladium was reduced with dofusin and dried at 160°C for 10 hours to obtain a supported catalyst.
When the palladium supported state of the obtained supported catalyst was measured using an X-ray microanalyzer, it was found that 96% or more of palladium was supported within 0.2 m of the surface layer of the support. A high proportion of platinum metal elements can be easily supported on the surface layer of the carrier, and catalysts supported with platinum metal elements in this way can be reduced with hydrogen gas or a reducing liquid such as hydrazine or formalin, and then washed with water and dried to release hydrogen. It becomes a catalyst that exhibits good performance as a chemical catalyst.

Claims (1)

[Claims] A method for supporting a platinum metal element on a porous carrier, the supported catalyst being characterized by immersing the porous carrier in advance in a hydrocarbon compound having 5 to 12 carbon atoms, and then impregnating it with an aqueous solution of the platinum metal element compound. manufacturing method.