Regeneration method and application of chloronitro aromatic hydrocarbon selective hydrogenation catalyst

Abstract

The invention relates to the technical field of catalysts, and particularly discloses a regeneration method of a chloronitro aromatic hydrocarbon selective hydrogenation catalyst. The regeneration method comprises the following steps: impregnating a part of the deactivated catalyst by adopting a titanium oxide precursor and a stabilizing solution, carbonizing, mixing the carbonized catalyst and the deactivated catalyst, adding the mixture into a regeneration kettle filled with a treatment solution, and decomposing organic impurities under the action of ultraviolet irradiation and microwaves; and carrying out microwave washing on the treated catalyst under the interaction effect of the organic acid and the organic solvent, so as to realize dredging of pore channels and recovery of active metal sites. According to the treatment method, organic impurities adsorbed in the catalyst can be effectively removed, and the catalytic performance is recovered. The method has the advantages of being simple, efficient, environmentally friendly and the like, the structure of the catalyst and the active metal loading state can be kept while it is guaranteed that organic impurities are removed, the activity of the catalyst is effectively recovered, and the use cost of the catalyst is reduced.

Description

[0001] (1) Technical field [0002] The invention relates to the technical field of catalysts, in particular to a regeneration method and application of a chlorinated nitroaromatic selective hydrogenation catalyst. [0003] (2) Background technology [0004] The products produced by the selective hydrogenation reaction of chloronitroaromatics are widely used in the production process of organic dyes, pesticides, synthetic fibers, plasticizers and printing and dyeing auxiliaries. According to different reaction conditions, different products can be obtained after hydrogenation reduction of chloronitroaromatics, mainly including nitroso compounds, hydroxylamine, azobenzenes and primary aramides. The hydrogenation pathway is mainly divided into direct pathway (nitroaromatics-nitrosobenzene-hydroxylamine-aniline) and condensation pathway (nitrobenzene-nitrosobenzene-azobenzene oxide-hydroazobenzene-aniline). [0005] At present, the selective hydrogenation catalysts of chloronitro...

AI Technical Summary

Problems solved by technology

Due to the relatively high cost of noble metal catalysts, and the catalytic performance of noble metal catalysts gradually decreases with the increase in the number of times the catalyst is applied, so in the actual production process, the shortened service life of the catalyst will directly lead to an increase in the production cost of the product

[0006] According to a large number of previous research results of the inventors, the main reason for the performance degradation of carbon-supported noble metal catalysts in the selective hydrogenation reduction reaction of chlorinated nitroaromatics is that organic impurities block the pores of the catalyst and cover the hydrogenation active sites, resulting in hydrogenation activity. reduction of

A large number of studies done by the inventor in the early stage also found that the effect of single organic solvent washing on restoring the specific surface area and pore volume of the deactivated catalyst is extremely limited

However, non-mild regeneration methods such as strong acid cleaning will accelerate the destruction of the catalyst support structure and the loss of precious metal components, which will further cause irreversible performance damage to the catalyst.

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