Amorphous alloy catalysts are used in the study of hydrogenation of m-clonitrobenzene


Ni-M-P (M=Cu, Ca, Zn, Sn, Co) amorphous alloy catalysts were prepared by chemical reduction, and the composition, structure and morphology of the catalysts were characterized by X-ray spectroscopy (EDS), X-ray diffraction (xRD) and transmission electron microscopy (TEM), and the performance of the prepared catalysts was systematically evaluated by the liquid phase catalytic hydrogenation of m-chloronitrobenzene as the target reaction, so as to solve the problem of hydrogen dehalogenation in the process of catalytic hydrogenation of m-chloroaniline. The results show that in the prepared ternary amorphous alloy catalyst, under the reaction conditions of the reaction temperature ll0 °C and hydrogen pressure of 1.0 MPa, Ni-Co-P shows high hydrogenation performance and inhibition of dehalogen dehalogenation performance when Ni:Co=1:1 (molar ratio) is not added without dehalogen inhibitor. The conversion rate of m-clonitrobenzene can reach 99.0%, and the selectivity of chloraniline can also reach 99.3%, and its conversion and selectivity are greatly improved compared with other ternary catalysts and Ni-P catalysts. The effect of adding a third component metal on the catalytic performance of Ni-P amorphous alloy catalysts was discussed and explained from the aspects of microstructure and electron effect of the 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.