Difference in activity between amorphous alloy catalysts and ordinary Raeney nickel


X-ray diffraction (XRD) analysis of the catalyst showed that the amorphous alloy catalyst was significantly different from the Raney Ni catalyst in crystal phase structure. The XRD spectra of Raney Ni catalyst were consistent with those of typical crystalline Ni, and diffraction peaks appeared at 2θ of 45°, 52°, and 76°, indicating that Ni in Raney Ni catalyst existed in a complete crystalline form. The amorphous catalyst has only one diffuse peak at 2θ to 45°, which indicates that Ni in the ZL series catalyst exists in amorphous form.
   
By conversion of particle size, specific surface area, pore volume and cyclohexanone hydrogenation probe reaction of amorphous catalysts and Raney Ni catalysts in industrial production. It can be seen that the specific surface area and pore volume of SRNA-4 catalyst are greater than those of Raney Ni catalyst when the particle size is the same, and the hydrogenation activity of cyclohexanone is more than twice that of conventional Raney Ni catalyst.

 

 

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Reni nickel catalyst science knowledge(1)

Physical and chemical properties: Reni nickel catalyst before activation is silver-gray amorphous powder (nickel-aluminum alloy powder), with a moderate degree of flammability, partial activation in the presence of water and the production of hydrogen easy agglomeration, long-term exposure to air is easy to weather. Nickel-aluminum alloy powder is activated into gray-black particles, accompanied by active hydrogen, extremely unstable, oxidative combustion in the air, must be immersed in water or ethanol for preservation. It was first used by American engineer Murray Rainey as a catalyst in the hydrogenation of vegetable oils. The preparation process is to treat nickel-aluminum alloy with concentrated sodium hydroxide solution, in this process, most of the aluminum will react with sodium hydroxide and dissolve, leaving a lot of micropores of different sizes. In this way, the surface of Raininickel is a fine gray powder, but from a microscopic point of view, each tiny particle in the powder is a three-dimensional porous structure, this porous structure greatly increases its surface area, and the large surface area brings high catalytic activity, which makes Raininickel widely used as a heterogeneous catalyst in organic synthesis and industrial hydrogenation reactions. Since "Rainey" is a registered trademark of Grace Chemicals, strictly speaking, only products manufactured by the company's Davidson Chemical Division can be called "Lanny Nickel". The term "metal backbone catalyst" or "sponge-metal catalyst" is used to refer to catalysts with a microporous structure and physical and chemical properties similar to Raney nickel.