JPS6316169B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a solid catalyst used as a reaction accelerating additive for example in hydrogenation reactions,
More specifically, it relates to a solid catalyst with excellent performance. Conventionally, solid catalysts supported by graphite are known to have effective functions as a support due to the graphite itself being chemically stable and having a relatively large specific surface area. . However, due to its brittle nature, graphite easily pulverizes. Therefore, when used as a carrier for a fixed catalyst, there is a risk that it will be pulverized and mixed into reaction products such as hydrogenation reactions. They were subject to constraints such as having to manufacture them in shapes that were difficult to recreate. Therefore, the inventor focused on the excellent performance of graphite and discovered a solid catalyst equipped with a carrier that does not cause the graphite to become powder and is not subject to restrictions on the shape of the graphite. In other words, this invention provides the powder surface of expanded graphite with
Nickel, cobalt, palladium, iron, chromium,
This invention relates to a fixed catalyst formed by supporting a catalytic metal selected from molybdenum, tungsten, platinum, etc., or an alloy containing these catalytic metals as a main component, and press-molding these. The fixed catalyst obtained in this way has not only the chemically stable properties of graphite and a relatively large specific surface area, but also the support obtained by expanding graphite. In addition, the expansion treatment dramatically increases the specific surface area (approximately 10 times the specific surface area of normal graphite), and as the overall surface area of the catalyst increases, the reaction area also increases, increasing the amount of contact with the catalyst surface. Adsorption and desorption effects are effectively carried out, and chemical reactions are significantly promoted. Furthermore, the expansion treatment softens the graphite as a whole and eliminates its brittleness, and the mutual contact between these powders due to pressure molding eliminates the pulverization of the expanded graphite. Further, since expanded graphite exhibits softening, it can be used in any shape without any restrictions. Expanded graphite used as the above-mentioned carrier is produced by acid treatment of flaky natural graphite or pyrolyzed graphite with well-organized crystals with a mixed acid of nitric acid and sulfuric acid, etc., and then heated to produce graphite with a certain directionality.
It is expanded to about twice its size to obtain so-called expanded graphite. The degree of expansion can be adjusted to a desired size depending on the concentration of the interlayer substance such as a mixed acid with respect to the graphite, the heating state, and the like. The metal deposited on the surface of the expanded graphite described above is deposited on the surface to a thickness of about 1 μm or less by an appropriate deposition method such as vacuum deposition, plating, or impregnation. In this case, since the effect of the catalytic reaction does not change much even if 1μ or more is deposited, 1μ or less is appropriate. Note that the deposited metal is not limited to metals such as nickel, cobalt, palladium, iron, and platinum, but also various metals suitable for other uses or alloys containing these various metals as main components may be deposited. Then, the powder obtained after metal deposition is compressed into a solid form by pressure forming such as press molding to provide a fixed catalyst, which is then cut into appropriate sizes for addition and used. It is. Next, one experimental result of the present invention will be explained in comparison with a conventional example. The table below shows the solid catalyst A of the present invention example (using an alloy of Ni and Fe as the catalyst metal) in the hydrogenation reaction,
As a conventional example, the degree of influence on chemical reactions of solid catalysts represented by symbols B and C, which are typically used in hydrogenation reactions, is compared.In order to make the conditions the same for all three, the reactants are Hexene was used, the product was hexane, and the reaction conditions were 20°C liquid phase. As the catalytic metal for each of the solid catalyst supports designated by symbols B and C, nickel, which is particularly suitable for hydrogenation reactions, was used by vacuum deposition to a thickness of 0.5 μm or less. In addition, as the catalyst metal of the solid catalyst A of the present invention example, expanded graphite is used as a carrier, so it has an excellent adsorption and desorption effect on the catalyst surface, so Ni- This was used to prove that even when Fe alloys are used, excellent effects can still be achieved.

[Table] As is clear from the table above, according to the solid catalyst A of the example of the present invention, the time required for the reaction to reach equilibrium is The time has been significantly reduced. This indicates that the catalytic action of Example A of the present invention was extremely effective during the reaction. In addition, when the powdered state of the reaction product was investigated after reaction equilibrium, it was found that in conventional example B using graphite as a carrier,
Although a slight amount of contamination was detected, no abnormalities such as powdered contamination were observed in other conventional example C and inventive example A.

Claims (1)

[Claims] 1. A catalyst metal selected from nickel, cobalt, palladium, iron, platinum, chromium, molybdenum, and tungsten, or an alloy containing these catalyst metals as a main component, is supported on the surface of expanded graphite powder,
A fixed catalyst characterized by being pressure-molded.