Preparation method of high-dispersibility m-dinitrobenzene hydrogenation structuring catalyst

Abstract

The invention discloses a preparation method of a high-dispersibility m-dinitrobenzene hydrogenation structuring catalyst, which comprises the following steps: (1) impregnating a cordierite honeycomb ceramic matrix coated with gamma-Al2O3 in a nickel nitrate impregnation liquid; (2) performing vacuum suction; (3) drying, and performing constant-temperature roasting to obtain a Ni / gamma-Al2O3 / cordierite structuring catalyst precursor; (4) repeatedly loading until the load mass percent of the active component Ni is 12-14%; and (5) reducing the catalyst precursor with H2 to obtain the high-dispersibility m-dinitrobenzene hydrogenation structuring catalyst. By changing the concentration of the impregnation liquid, controlling the impregnation time and introducing the vacuum suction action, the metal dispersion degree is increased from 9.3% (in the traditional method) to 38.4%; and a nickel-based structuring catalyst having excellent dispersibility, namely the high-dispersibility m-dinitrobenzene hydrogenation structuring catalyst, can be prepared.

Description

technical field [0001] The invention belongs to the field of chemical industry, and in particular relates to a preparation method of a highly dispersed m-dinitrobenzene hydrogenation structured catalyst. Background technique [0002] Structured catalysts are increasingly used in petrochemical processes. In terms of catalytic hydrogenation, the production of hydrogen peroxide from anthraquinone is the earliest application of structured catalysts to achieve industrialized heterogeneous reactions. The monolithic structure of structured catalysts makes the operation simple Easy to implement and realize large-scale production. Nijhuis et al. Ni / Al 2 o 3 / cordierite structured catalysts are applied to the hydrogenation reaction of α-methylstyrene and benzyl alcohol, and the reactivity in the structured reactor and the traditional trickle bed reactor are compared respectively, and the results show that the former has a higher selectivity and yield. Grezee et al. preliminarily d...

AI Technical Summary

Problems solved by technology

However, the cordierite honeycomb ceramic structured matrix cannot meet the needs of structured catalysts due to its low specific surface area. gamma -Al 2 o 3 to coat

Nevertheless, the specific surface area of ​​the coated structured catalyst is still low, generally no more than 40m 2 / g, when the impregnation method is used to load the active components, the main problem is that the dispersion of the active components is low when the active components are loaded, and the metal particles are large, which affects the catalyst activity.

[0004] In the invention patent CN200510083037.6, a vacuum impregnation method is disclosed to prepare a powder catalyst with high dispersion, amorphous state and high desulfurization activity, and the modified γ-Al 2 o 3 As a carrier, the molybdenum salt solution added with surfactant was slowly added to the vacuumed carrier, dried on a water bath shaker after full contact, and finally calcined step by step in a muffle furnace to prepare a granular catalyst with good performance , but this method is not suitable for the preparation of structured catalysts

[0005] In the invention patent CN200710011729.9, a palladium-ruthenium bimetallic powder catalyst prepared by the traditional impregnation method is disclosed in the production of m-phenylenediamine, and a higher yield is obtained, but there is a shortcoming that the product and the catalyst are not easy to separate

[0006] The impregnation method is used to load the active components. Although the operation is simple, the active components are not easy to disperse uniformly. The structured catalyst is prepared by loading the active components by excessive impregnation and vacuum suction, and is used for the catalytic hydrogenation of m-dinitrobenzene to prepare m-dinitrobenzene. Among phenylenediamines, there has been no report so far

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