Nitrogen-doped carbon-coated noble metal liquid phase hydrogenation catalyst, and preparation method and application thereof

Abstract

The invention discloses a nitrogen-doped carbon-coated noble metal liquid phase hydrogenation catalyst, and a preparation method and application thereof. The preparation method is implemented according to the following steps: (1) carrying out acid pickling on an activated carbon material; (2) adding the activated carbon material into a pre-prepared noble metal precursor solution for dipping treatment; (3) performing hydrogen reduction to obtain a noble metal catalyst; (4) carrying out carbon coating on the noble metal catalyst obtained in the step (3); and (5) roasting in an inert atmosphere to obtain the nitrogen-doped carbon-coated noble metal liquid phase hydrogenation catalyst. The invention provides the application of the nitrogen-doped carbon-coated noble metal liquid phase hydrogenation catalyst in synthesis of aniline from nitrobenzene, synthesis of CLT acid from 2-nitro-4-methyl-5-chlorobenzenesulfonic acid through reduction and synthesis of p-aminobenzene sulfonic acid from p-nitrobenzenesulfonic acid through reduction, and the catalyst has high conversion rate, high selectivity and high stability.

Description

(1) Technical field [0001] The invention relates to the technical field of catalysts, in particular to a nitrogen-doped carbon-coated noble metal liquid-phase hydrogenation catalyst with good sulfur resistance performance and its preparation method and application. (2) Background technology [0002] Precious metal catalysts can realize hydrogenation in chemical reactions, and are widely used in fine chemical industry, energy chemical industry, environmental protection and other fields. However, precious metal catalysts have relatively high requirements on the reaction environment, and the existence of trace sulfur impurities in the raw materials will easily lead to poisoning of the precious metal catalyst, resulting in reduced activity or even deactivation of the catalyst, thus prolonging the reaction time or even making it impossible to proceed, causing irreparable damage to production. influences. Removing trace amounts of sulfur impurities from feedstocks requires a larg...

AI Technical Summary

Problems solved by technology

[0004] At present, in the production and application, the catalyst activity caused by sulfur impurities is low or even completely deactivated, and the catalytic activity is difficult to recover, which is a serious obstacle restricting the industrialization of many catalytic processes.

Because sulfur-containing compounds can be chemisorbed on the active metal and cover the active center (or dissociated adsorption occurs on the metal, and the reduced sulfur has a strong bond with the noble metal), resulting in catalyst deactivation; under harsher conditions, Sulfur atoms even gradually enter the active metal phase to form crystal phases such as sulfide salts. The formation of this sulfide crystal phase further reduces the activity of the catalyst to some extent.

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